Journal articles on the topic 'Mammary glands'
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1
Biswas, Swarajit Kumar, Saswati Banerjee, Ginger Wendolyn Baker, Chieh-Yin Kuo, and Indrajit Chowdhury. "The Mammary Gland: Basic Structure and Molecular Signaling during Development." International Journal of Molecular Sciences 23, no. 7 (March 31, 2022): 3883. http://dx.doi.org/10.3390/ijms23073883.
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The mammary gland is a compound, branched tubuloalveolar structure and a major characteristic of mammals. The mammary gland has evolved from epidermal apocrine glands, the skin glands as an accessory reproductive organ to support postnatal survival of offspring by producing milk as a source of nutrition. The mammary gland development begins during embryogenesis as a rudimentary structure that grows into an elementary branched ductal tree and is embedded in one end of a larger mammary fat pad at birth. At the onset of ovarian function at puberty, the rudimentary ductal system undergoes dramatic morphogenetic change with ductal elongation and branching. During pregnancy, the alveolar differentiation and tertiary branching are completed, and during lactation, the mature milk-producing glands eventually develop. The early stages of mammary development are hormonal independent, whereas during puberty and pregnancy, mammary gland development is hormonal dependent. We highlight the current understanding of molecular regulators involved during different stages of mammary gland development.
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Hambarova, G. H., H. E. Askerova, and M. S. Panakhova. "Normal decoding of the structure of the chest in the light of possibilities a new generation of high-frequency ultrasonographic sensors." HEALTH OF WOMAN, no. 3(129) (April 30, 2018): 123–27. http://dx.doi.org/10.15574/hw.2018.129.123.
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Over the years of the existence of echography in Japan and the English-speaking countries, a large number of atlases and a manual textbookы where the authors describe the echo anatomy of the mammary glands have been published. The rapid technological growth has led to the fact that the echo anatomy of the mammary glands described on the basis of equipment from the 80s-90s does not correspond to the capabilities of modern ultrasonic devices. There was a need to clarify and detail the echographic image of the mammary glands, taking into account the possibilities of a new generation of 10–12 MHz high-frequency, and also upon the use of the new Doppler techniques. The anatomical structures of the mammary glands are clearly differentiated using modern ultrasound equipment. The breast tissue is normally varied widely and depends on the ratio of fat, connective and glandular tissue. The USM allows visualizing the tomographic section of the image of a fragment of the mammary gland from the skin cover to the chest wall. Key words: breast glande, ultrasonography, dopрlerography, US-sensor.
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Tian, Lei, Shancheng Guo, Zhiye Zhao, Yuxu Chen, Chunmei Wang, Qingzhang Li, and Ye Li. "miR-30a-3p Regulates Autophagy in the Involution of Mice Mammary Glands." International Journal of Molecular Sciences 24, no. 18 (September 20, 2023): 14352. http://dx.doi.org/10.3390/ijms241814352.
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The mammary gland undergoes intensive remodeling during the lactation cycle, and the involution process of mammary gland contains extensive epithelial cells involved in the process of autophagy. Our studies of mice mammary glands suggest that miR-30a-3p expression was low during involution compared with its high expression in the mammary glands of lactating mice. Then, we revealed that miR-30a-3p negatively regulated autophagy by autophagy related 12 (Atg12) in mouse mammary gland epithelial cells (MMECs). Restoring ATG12, knocking down autophagy related 5 (Atg5), starvation, and Rapamycin were used to further confirm this conclusion. Overexpression of miR-30a-3p inhibited autophagy and altered mammary structure in the involution of the mammary glands of mice, which was indicative of alteration in mammary remodeling. Taken together, these results elucidated the molecular mechanisms of miR-30a-3p as a key induction mediator of autophagy by targeting Atg12 within the transition period between lactation and involution in mammary glands.
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Meador, Vincent P., and Billy L. Deyoe. "Effect of milk stasis on Brucella abortus infection of the mammary gland in goats." American Journal of Veterinary Research 52, no. 6 (June 1, 1991): 886–90. http://dx.doi.org/10.2460/ajvr.1991.52.06.886.
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SUMMARY To compare the effects of milk stasis and milk flow on Brucella abortus infection of the mammary gland under the same systemic conditions, primiparous goats (n = 5) were inoculated iv with B abortus on the day of parturition, and suckling by their neonates was restricted to one mammary gland. Goats were euthanatized and necropsied at 3 weeks after inoculation, and milk, mammary glands, and supramammary lymph nodes were evaluated by bacteriologic, histologic, and immunoenzymatic staining techniques. Nonnursed mammary glands had high titers of brucellae in milk, moderate interstitial mastitis, and brucellar antigen in macrophages located primarily in alveolar and ductal lumina. Brucellae often filled the macrophage cytoplasm. In contrast, nursed mammary glands had fewer brucellae in milk, minimal inflammatory changes, and no detectable brucellar antigen in histologic sections. Hyperplastic changes were only seen in supramammary lymph nodes draining nonnursed mammary glands; these contained more brucellae than lymph nodes draining nursed mammary glands. These studies show that milk stasis may be the sole cause of increased susceptibility of nonnursed mammary glands to B abortus infection.
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Payan-Carreira, Rita, and Ana C. Martins-Bessa. "Ultrasonographic assessment of the feline mammary gland." Journal of Feline Medicine and Surgery 10, no. 5 (October 2008): 466–71. http://dx.doi.org/10.1016/j.jfms.2008.03.006.
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The aim of this study is to characterise the feline mammary echotexture using B-mode ultrasonography, which is not routinely used to examine the feline mammary gland. Using a 5–9 MHz linear transducer the ultrasonographic appearance of non-stimulated and stimulated mammary glands was determined in 35 mature intact non-pregnant, pregnant and lactating queens aged from 16 months to 8 years. In intact non-pregnant queens, mammary glands are fairly underdeveloped and on the ultrasonograms they appear with a regular hypoechoic texture and generally show a thickness of less than 2.0 mm. The stimulated mammary tissue typically presents a more hyperechoic appearance compared to the non-stimulated gland and a fine granular echotexture. Maximum echogenicity of the mammary gland is reached during lactation. In late pregnancy, the mammary glands reach 6–9 mm in thickness. During lactation, the size of the glands depends on the existence of a suckling stimulus, with the suckled glands reaching about 11 mm in thickness. Ductal structures can only be imaged during late pregnancy and lactation. Ultrasonographic evaluation of the feline mammary gland can become a valuable diagnostic tool to characterise physiological changes and may further contribute to a better characterisation of diseased mammary tissue.
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Fang, Rendong, Jingchun Cui, Tengteng Cui, Haiyong Guo, Hisaya Ono, Chun-Ho Park, Masashi Okamura, Akio Nakane, and Dong-Liang Hu. "Staphylococcal Enterotoxin C Is an Important Virulence Factor for Mastitis." Toxins 11, no. 3 (March 2, 2019): 141. http://dx.doi.org/10.3390/toxins11030141.
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Staphylococcus aureus is an important bacterial pathogen causing bovine mastitis, but little is known about the virulence factor and the inflammatory responses in the mammary infection. Staphylococcal enterotoxin C (SEC) is the most frequent toxin produced by S. aureus, isolated from bovine mastitis. To investigate the pathogenic activity of SEC in the inflammation of the mammary gland and the immune responses in an animal model, mouse mammary glands were injected with SEC, and the clinical signs, inflammatory cell infiltration, and proinflammatory cytokine production in the mammary glands were assessed. SEC induced significant inflammatory reactions in the mammary gland, in a dose-dependent manner. SEC-injected mammary glands showed a severe inflammation with inflammatory cell infiltration and tissue damage. In addition, interleukin (IL)-1β and IL-6 production in the SEC-injected mammary glands were significantly higher than those in the PBS control glands. Furthermore, the SEC-induced inflammation and tissue damage in the mammary gland were specifically inhibited by anti-SEC antibody. These results indicated, for the first time, that SEC can directly cause inflammation, proinflammatory cytokine production, and tissue damage in mammary glands, suggesting that SEC might play an important role in the development of mastitis associated with S. aureus infection. This finding offers an opportunity to develop novel treatment strategies for reduction of mammary tissue damage in mastitis.
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Vitásek, R., and H. Dendisová. "Treatment of Feline Mammary Fibroepithelial Hyperplasia Following a Single Injection of Proligestone." Acta Veterinaria Brno 75, no. 2 (2006): 295–97. http://dx.doi.org/10.2754/avb200675020295.
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A case of fibroepithelial hyperplasia of the mammary gland in the cat is reported. A seven-monthold female cat was presented for diffuse enlargement of all of the mammary glands. The cat was treated with proligestone (Covinan®) for the suppression of estrus. Four weeks later all 8 mammary glands were asymmetrically enlarged. There was ulceration of one gland. Sonographic imaging of the affected mammary glands showed homogeneous and granular structures. The patient was treated with subcutaneous injections of 10 mg/kg aglépristone (Alizine®) on days 1, 2, 7, 14 and 21. Within six weeks the mammary glands had completely regressed. No side effects were observed. It is the first case of fully documented feline mammary fibroepithelial hyperplasia and its treatment in the Czech Republic.
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Palin, M. F., D. Beaudry, C. Roberge, and C. Farmer. "Expression levels of STAT5A and STAT5B in mammary parenchymal tissue from Upton-Meishan and Large White gilts." Canadian Journal of Animal Science 82, no. 4 (December 1, 2002): 507–18. http://dx.doi.org/10.4141/a01-091.
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The implication of STAT5A and STAT5B in mammary gland development and maintenance of lactation is well documented in rodents and humans. However, little is known regarding their roles in mammary gland development during gestation in pigs. We identified and analyzed the complete coding sequences of swine STAT5A and STAT5B and evaluated their mRNA levels in mammary glands of gestating gilts (day 110) in two different breeds, Upton-Meishan and Large White. Sequence analysis revealed a new APASA insertion in the STAT5A amino acid sequence that is in close proximity to residue Tyr 699 and whose phosporylation leads to the activation of target genes’ transcription. STAT5A mRNA levels were higher in Upton-Meishan than in Large White. In both breeds, STAT5B mRNA levels were higher than those of STAT5A , which is contrary to what was found in other mammals. A correlation between circulating IGF-I levels and STAT5B mRNA levels in the mammary gland was noticed in the Upton-Meishan breed only. STAT5B mRNA levels in mammary tissue of Large White gilts were highly correlated with extra-parenchymal tissue weight, parenchymal tissue weight, total parenchymal DNA, RNA and RNA/DNA ratio. In Upton-Meishan gilts, correlations were observed only between extra-parenchymal weight and STAT5A and STAT5B mRNA levels. These results indicate that there are significant differences in mRNA levels of STAT5A and STAT5B in the mammary glands of pregnant gilts when compared to other mammals, and between swine breeds. Key words: Mammary glands, signal transducers, pregnancy, kinases, pig, expression
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Conn, David Bruce, Cary A. Hefty, and Sarah Cross Owen. "Infection of Mammary Glands of Small Mammals in Eastern North America by Helminths." Animals 11, no. 11 (November 10, 2021): 3207. http://dx.doi.org/10.3390/ani11113207.
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To determine whether small mammals living in natural settings harbor helminth infections in their mammary glands, we conducted a survey of helminths infecting rodents and soricimorphs in three widespread locations in the eastern United States: states of New York, Tennessee, and Georgia. We examined all the primary organs in all hosts, and identified all helminths. We also excised the complete mammary glands within their subcutaneous fat pads, then stained and mounted each whole mammary gland set for microscopical examination. A total of 53 individual hosts were examined, including 32 Peromyscus spp., 11 Mus musculus, 5 Sigmodon hispidus, 4 Clethrionomys gapperi, and 1 Blarina carolinensis. Helminths collected included Heligmosomoides sp., Hymenolepisdiminuta, Hymenolepis nana, Pterygodermatites peromysci, Schistosomatium douthitti, Syphacia obvelata, Syphacia sigmodontis, and Trichostrongylus sigmodontis. Four S. hispidus were infected by T. sigmodontis in the small intestine; in all four, we also found nematode larvae in lactiferous duct lumen and lactogenic tissue of the mammary glands. We were unable to identify the species of nematode larvae, but the co-occurrence with T. sigmodontis in all cases may suggest an association. Future studies should seek to identify such larvae using molecular and other methods, and to determine the role of these mammary nematode larvae in the life cycle of the identified species. No other host species harbored helminths in the mammary glands. Overall, our results suggest that mammary infections in wild small mammals are not common, but warrant inclusion in future surveys.
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Kruk, O. Yu. "Clinic-anamnestic factors of the risk of hyperplastic diseases an endometrium, mammary glands and their combination at women of perimenopause age." HEALTH OF WOMAN, no. 6(142) (July 29, 2019): 71–73. http://dx.doi.org/10.15574/hw.2019.142.71.
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The objective: to improve well-timed diagnostics of hyperplastic diseases the endometrium and mammary glands at women of perimenopause age on the basis of studying of the main clinical risk factors. Materials and methods. Were surveyed 145 patients of perimenopause age, 15 from which (group of control) the women who didn’t have hyperplastic diseases of organs of genesial system (made of the contingent gynecological and mammology healthy). Results. Clinical-anamnestic risk factors of the isolated hyperplastic process an endometrium are: early menarche, long and plentiful menses, inflammatory diseases of genitalias and use of endometrial methods of contraception. Probability of development of the isolated hyperplasia of mammary glands define: the burdened family anamnesis on a cancer of a mammary gland, the menarche, lack of a lactemia or its duration less than 6 months, pyoinflammatory diseases of mammary glands is later. By risk factors of the combined hyperplastic process in mammary glands and an endometrium are defined: the burdened family anamnesis on a cancer of a mammary gland, the menarche, a long becoming of a menstrual cycle (over a year) is later, than a disease of a thyroid gland and cardiac vascular system, numerous abortions. All taped clinical-anamnestic data indicate disturbance of endocrine balance at patients, both with isolated, and with the combined hyperplastic diseases an endometrium and mammary glands. Conclusion. The received results needs to be considered when developing tactics of forecasting and early diagnostics of the combined pathology of uterus and mammary glands at women of perimenopause age. Key words: hyperplastic processes of uterus and mammary glands, risk factors, perimenopause age.
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Salisbury, S., and M. S. Bauer. "Reconstruction of Distal Hind Limb Injuries in Cats Using the Caudal Superficial Epigastric Skin Flap." Veterinary and Comparative Orthopaedics and Traumatology 08, no. 02 (1995): 98–101. http://dx.doi.org/10.1055/s-0038-1632436.
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SummaryFour cats were admitted for treatment of traumatic wounds distal to the tarsus. The caudal superficial epigastric skin flap was used to reconstruct each wound. In two cats, an initial flap that included all four mammary glands was attempted, but the segment of the flap that incorporated the first mammary gland underwent necrosis. Caudal superficial epigastric flaps that included mammary glands ## 2, 3 and 4 survived completely in three cats. In one cat the distal 3.0 cm, including the second mammary gland, underwent necrosis after a seroma formed. These flaps covered defects that extended beyond the tarsus in all cats and to the digits in two cats.Four cats with traumatic wounds distal to the tarsus underwent reconstructive surgery. Caudal superficial epigastric flaps that included mammary glands ## 2, 3 and 4 were used to reconstruct the wounds. In two cats, all four mammary glands were initially included with the flap. In these two cats, the distal portions of the flaps including the first mammary gland underwent necrosis. The necrotic areas were debrided and the flaps were repositioned to cover the defects. The remainder of these flaps and one flap that included mammary glands ## 2–4 survived completely. All flaps covered defects that extended beyond the tarsus in all cats and to the digits in two cats.
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Lund, L. R., S. F. Bjorn, M. D. Sternlicht, B. S. Nielsen, H. Solberg, P. A. Usher, R. Osterby, et al. "Lactational competence and involution of the mouse mammary gland require plasminogen." Development 127, no. 20 (October 15, 2000): 4481–92. http://dx.doi.org/10.1242/dev.127.20.4481.
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Urokinase-type plasminogen activator expression is induced in the mouse mammary gland during development and post-lactational involution. We now show that primiparous plasminogen-deficient (Plg(−/−)) mice have seriously compromised mammary gland development and involution. All mammary glands were underdeveloped and one-quarter of the mice failed to lactate. Although the glands from lactating Plg(−/−) mice were initially smaller, they failed to involute after weaning, and in most cases they failed to support a second litter. Alveolar regression was markedly reduced and a fibrotic stroma accumulated in Plg(−/−) mice. Nevertheless, urokinase and matrix metalloproteinases (MMPs) were upregulated normally in involuting glands of Plg(−/−) mice, and fibrin did not accumulate in the glands. Heterozygous Plg(+/−) mice exhibited haploinsufficiency, with a definite, but less severe mammary phenotype. These data demonstrate a critical, dose-dependent requirement for Plg in lactational differentiation and mammary gland remodeling during involution.
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Golovkina, Tatyana V., Jaquelin P. Dudley, and Susan R. Ross. "B and T Cells Are Required for Mouse Mammary Tumor Virus Spread Within the Mammary Gland." Journal of Immunology 161, no. 5 (September 1, 1998): 2375–82. http://dx.doi.org/10.4049/jimmunol.161.5.2375.
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Abstract Mouse mammary tumor virus (MMTV) is an infectious retrovirus transmitted through milk from mother to newborns. MMTV encodes a superantigen (SAg) whose activity is indispensable for the virus life cycle, since a genetically engineered virus with a mutation in the sag gene neither amplified in cells of the immune system of suckling pups nor infected their mammary glands. When wild-type MMTV was injected directly into the mammary glands of uninfected pubescent mice, their lymphoid as well as mammary gland cells became virus infected. To test whether this infection of lymphoid cells was dependent on SAg activity and required for virus spread within the mammary gland, we performed mammary gland injections of wild-type MMTV(C3H) into two strains of transgenic mice that lacked SAg-cognate, Vβ14+ T cells. Neither the MTV-ORF or LEL strains showed infection of their mammary glands. Moreover, no MMTV infection of their peripheral lymphocytes was detected. Similar experiments with mice lacking B cells (μ-chain knockouts) showed no detectable virus spread in the mammary glands or lymphoid tissues. These data suggest that SAg activity and MMTV-infected lymphocytes are required, not only for initial steps of viral infection, but also for virus spread within the mammary gland. Virus spread at late times in infection determines whether MMTV induces mammary tumors.
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Imbert, Alexandra, Rachel Eelkema, Sara Jordan, Helen Feiner, and Pamela Cowin. "Δn89β-Catenin Induces Precocious Development, Differentiation, and Neoplasia in Mammary Gland." Journal of Cell Biology 153, no. 3 (April 30, 2001): 555–68. http://dx.doi.org/10.1083/jcb.153.3.555.
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To investigate the role of β-catenin in mammary gland development and neoplasia, we expressed a stabilized, transcriptionally active form of β-catenin lacking the NH2-terminal 89 amino acids (ΔN89β-catenin) under the control of the mouse mammary tumor virus long terminal repeat. Our results show that ΔN89β-catenin induces precocious lobuloalveolar development and differentiation in the mammary glands of both male and female mice. Virgin ΔN89β-catenin mammary glands resemble those found in wild-type (wt) pregnant mice and inappropriately express cyclin D1 mRNA. In contrast to wt mammary glands, which resume a virgin appearance after cessation of lactation, transgenic mammary glands involute to a midpregnant status. All transgenic females develop multiple aggressive adenocarcinomas early in life. Surprisingly, the ΔN89β-catenin phenotype differs from those elicited by overexpression of Wnt genes in this gland. In particular, ΔN89β-catenin has no effect on ductal side branching. This suggests that Wnt induction of ductal branching involves additional downstream effectors or modulators.
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Muraoka, Rebecca S., Anne E. G. Lenferink, Jean Simpson, Dana M. Brantley, L. Renee Roebuck, F. Michael Yakes, and Carlos L. Arteaga. "Cyclin-Dependent Kinase Inhibitor P27Kip1 Is Required for Mouse Mammary Gland Morphogenesis and Function." Journal of Cell Biology 153, no. 5 (May 21, 2001): 917–32. http://dx.doi.org/10.1083/jcb.153.5.917.
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We have studied the role of the cyclin-dependent kinase (Cdk) inhibitor p27Kip1 in postnatal mammary gland morphogenesis. Based on its ability to negatively regulate cyclin/Cdk function, loss of p27 may result in unrestrained cellular proliferation. However, recent evidence about the stabilizing effect of p27 on cyclin D1–Cdk4 complexes suggests that p27 deficiency might recapitulate the hypoplastic mammary phenotype of cyclin D1–deficient animals. These hypotheses were investigated in postnatal p27-deficient (p27−/−), hemizygous (p27+/−), or wild-type (p27+/+) mammary glands. Mammary glands from p27+/− mice displayed increased ductal branching and proliferation with delayed postlactational involution. In contrast, p27−/− mammary glands or wild-type mammary fat pads reconstituted with p27−/− epithelium produced the opposite phenotype: hypoplasia, low proliferation, decreased ductal branching, impaired lobuloalveolar differentiation, and inability to lactate. The association of cyclin D1 with Cdk4, the kinase activity of Cdk4 against pRb in vitro, the nuclear localization of cyclin D1, and the stability of cyclin D1 were all severely impaired in p27−/− mammary epithelial cells compared with p27+/+ and p27+/− mammary epithelial cells. Therefore, p27 is required for mammary gland development in a dose-dependent fashion and positively regulates cyclin D–Cdk4 function in the mammary gland.
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Mustafi, Devkumar, Abby Leinroth, Xiaobing Fan, Erica Markiewicz, Marta Zamora, Jeffrey Mueller, Suzanne D. Conzen, and Gregory S. Karczmar. "Magnetic Resonance Angiography Shows Increased Arterial Blood Supply Associated with Murine Mammary Cancer." International Journal of Biomedical Imaging 2019 (January 17, 2019): 1–6. http://dx.doi.org/10.1155/2019/5987425.
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Breast cancer is a major cause of morbidity and mortality in Western women. Tumor neoangiogenesis, the formation of new blood vessels from pre-existing ones, may be used as a prognostic marker for cancer progression. Clinical practice uses dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) to detect cancers based on increased blood flow and capillary permeability. However, DCE-MRI requires repeated injections of contrast media. Therefore we explored the use of noninvasive time-of-flight (TOF) MR angiography for serial studies of mouse mammary glands to measure the number and size of arteries feeding mammary glands with and without cancer. Virgin female C3(1) SV40 TAg mice (n=9), aged 18-20 weeks, were imaged on a 9.4 Tesla small animal scanner. Multislice T2-weighted (T2W) images and TOF-MRI angiograms were acquired over inguinal mouse mammary glands. The data were analyzed to determine tumor burden in each mammary gland and the volume of arteries feeding each mammary gland. After in vivo MRI, inguinal mammary glands were excised and fixed in formalin for histology. TOF angiography detected arteries with a diameter as small as 0.1 mm feeding the mammary glands. A significant correlation (r=0.79; p< 0.0001) was found between tumor volume and the arterial blood volume measured in mammary glands. Mammary arterial blood volumes ranging from 0.08 mm3 to 3.81 mm3 were measured. Tumors and blood vessels found on in vivo T2W and TOF images, respectively, were confirmed with ex vivo histological images. These results demonstrate increased recruitment of arteries to mammary glands with cancer, likely associated with neoangiogenesis. Neoangiogenesis may be detected by TOF angiography without injection of contrast agents. This would be very useful in mouse models where repeat placement of I.V. lines is challenging. In addition, analogous methods could be tested in humans to evaluate the vasculature of suspicious lesions without using contrast agents.
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Golovkina, Tatyana V. "A Novel Mechanism of Resistance to Mouse Mammary Tumor Virus Infection." Journal of Virology 74, no. 6 (March 15, 2000): 2752–59. http://dx.doi.org/10.1128/jvi.74.6.2752-2759.2000.
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ABSTRACT Exogenous mouse mammary tumor virus (MMTV) is carried from the gut of suckling pups to the mammary glands by lymphocytes and induces mammary gland tumors. MMTV-induced tumor incidence in inbred mice of different strains ranges from 0 to as high as 100%. For example, mice of the C3H/HeN strain are highly susceptible, whereas mice of the I/LnJ strain are highly resistant. Of the different factors that together determine the susceptibility of mice to development of MMTV-induced mammary tumors, genetic elements play a major role, although very few genes that determine a susceptibility-resistance phenotype have been identified so far. Our data indicate that MMTV fails to infect mammary glands in I/LnJ mice foster nursed on viremic C3H/HeN females, even though the I/LnJ mammary tissue is not refractory to MMTV infection. Lymphocytes from fostered I/LnJ mice contained integrated MMTV proviruses and shed virus but failed to establish infection in the mammary glands of susceptible syngeneic (I × C3H.JK)F1 females. Based on the susceptible-resistant phenotype distribution in N2 females, both MMTV mammary gland infection and mammary gland tumor development in I/LnJ mice are controlled by a single locus.
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Santos, Sarah J., Sandra Z. Haslam, and Susan E. Conrad. "Signal Transducer and Activator of Transcription 5a Mediates Mammary Ductal Branching and Proliferation in the Nulliparous Mouse." Endocrinology 151, no. 6 (April 14, 2010): 2876–85. http://dx.doi.org/10.1210/en.2009-1282.
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Signal transducer and activator of transcription (Stat)5a is a critical regulator of mammary gland development. Previous studies have focused on Stat5a’s role in the late pregnant and lactating gland, and although active Stat5a is detectable in mammary epithelial cells in virgin mice, little is known about its role during early mammary gland development. In this report, we compare mammary gland morphology in pubertal and adult nulliparous wild-type and Stat5a−/− mice. The Stat5a-null mammary glands exhibited defects in secondary and side branching, providing evidence that Stat5a regulates these processes. In addition, Stat5a−/− mammary glands displayed an attenuated proliferative response to pregnancy levels of estrogen plus progesterone (E+P), suggesting that it plays an important role in early pregnancy. Finally, we examined one potential mediator of Stat5a’s effects, receptor activator of nuclear factor-κB ligand (RANKL). Stat5a−/− mammary glands were defective in inducing RANKL in response to E+P treatment. In addition, regulation of several reported RANKL targets, including inhibitor of DNA binding 2 (Id2), cyclin D1, and the cyclin-dependent kinase inhibitor p21Waf1/Cip1, was altered in Stat5a−/− mammary cells, suggesting that one or more of these proteins mediate the effects of Stat5a in E+P-treated mammary epithelial cells.
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Moraes, Nayara S., and Naida C. Borges. "Sonographic Assessment of the Normal and Abnormal Feline Mammary Glands and Axillary and Inguinal Lymph Nodes." Veterinary Medicine International 2021 (July 2, 2021): 1–7. http://dx.doi.org/10.1155/2021/9998025.
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Ultrasound has been used as a diagnostic tool in normal mammary glands and mammary tumors of several species. This study aims to describe the B-mode and Doppler ultrasound features of the mammary glands and draining lymph nodes in 32 adult female cats. Group 1 (G1) consisted of 22 cats without changes in the mammary glands. The average age was 45 ± 25.09 months, where 63.6% (n = 14) were neutered and 31.8% (n = 7) had received progestin at some point for reproductive control. Mammary gland structure was predominantly hypoechoic and homogeneous, with well-defined margins. The average thickness was 1.52 ± 1.59 mm, although it may be affected by estrus, pregnancy, and lactation. In G1, 100% of lymph nodes were homogeneous, 98% were hypoechoic, and 100% were with well-defined margins and hilar vascularization. Group 2 (G2) consisted of 10 cats with mammary nodules. The average age was 88.8 ± 40.5 months, and 70% were intact and all had already received progestin. Ultrasound demonstrated enlarged mammary glands, with nodules of different textures clinically, mainly affecting the abdominal mammary glands (61%). In 33.33%, there were visible mammary ducts. Only 54.17% were homogeneous, 95.83% were hypoechoic, and the margins were regular in 52.08%. Lymph nodes in abnormal mammary chains may present changes in size, shape, echotexture, and echogenicity. Ultrasound examination of the mammary glands and lymph nodes are possible to evaluate the entire mammary chain as well the superficial inguinal and axillary lymph nodes for abnormalities in the feline.
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Musina, E. V., and I. Y. Kogan. "The effect of Metformin on fibrocystic breast disease in women with insulin resistance." Tumors of female reproductive system 14, no. 3 (October 16, 2018): 19–24. http://dx.doi.org/10.17650/1994-4098-2018-14-3-19-24.
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A little studied question is the development mechanism, timely diagnostics, treatment and prevention of the fibrocystic breast disease at patients with insulin resistance. One of the possible perspective directions of pathogenetic impact on tissues of a mammary gland at the mastopathy associated with a giperinsulinemiya and insulin resistance is use of metformin. Now clinical trials on use of metformin at cancer of mammary glands continue. Data on use of medicines of this group at patients with fibrocystic breast disease in domestic and foreign literature are absent.Objective:assessment of influence of metformin on clinical displays of fibrocystic breast disease and ultrasonic characteristics of a parenchyma of mammary glands at patients with insulin resistance.Materials and methods.As therapy of fibrocystic breast disease patients received metformin in a dose of 1500 mg a day. Dynamic control of a clinical picture of a disease and ultrasonic indicators of a parenchyma of a mammary gland carried out in 3 and 6 months from the beginning of therapy.Results and conclusion.In 6 months of therapy there was a reliable decrease in frequency of a mastalgiya, change of an ultorasound picture of mammary glands: echogenicity of a parenchyma of mammary glands – became sredeny in 95,9% of cases, there was a reliable reduction of thickness of a parenchyma of mammary glands (from 15.5 mm to 10. 5 mm) and diameter of lacteal channels (from 1.7 mm to 0.9 mm). The obtained data on positive influence of metformin on the clinical course of mastopathy and structural changes of a parenchyma of mammary glands at patients with fibrocystic breast disease and insulin resistance allow to consider similar approach as the perspective direction of pathogenetic influence at such pathological association.
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Li, Xiangdong, Anni Wärri, Sari Mäkelä, Tommi Ahonen, Tomi Streng, Risto Santti, and Matti Poutanen. "Mammary Gland Development in Transgenic Male Mice Expressing Human P450 Aromatase." Endocrinology 143, no. 10 (October 1, 2002): 4074–83. http://dx.doi.org/10.1210/en.2002-220181.
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Abstract We recently generated a transgenic mouse strain that expresses the human aromatase gene under the ubiquitin C promoter (AROM+). We have previously shown that in these mice the serum estradiol concentration is highly elevated, whereas the testosterone concentration is decreased. In the present study we examined mammary gland development in AROM+ male mice at different ages and found that the mammary glands of AROM+ males undergo ductal and alveolar development morphologically resembling that of terminally differentiated female mammary glands, expressing mRNA for a milk protein gene (β-casein). The male mammary glands also express multiple hormone receptors typical for female mammary gland: estrogen receptor α and β, progesterone receptor, and PRL receptor. Furthermore, data showed activation of the Stat5 (signal transducer and activator of transcription 5) signaling pathway in the AROM+ male mammary gland. Interestingly, the phenotype observed is in part reversible. Treatment with finrozole, a specific aromatase inhibitor, caused an involution of the differentiated phenotype of the mammary gland, marked by the disappearance of alveolar structures and the majority of the tertiary side branches of the ducts. The present animal model is a valuable tool for better understanding the cellular and molecular mechanisms involved in the development of gynecomastia.
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Wang, Wenjing, Xupeng Zang, Yonglun Liu, Yunyi Liang, Gengyuan Cai, Zhenfang Wu, and Zicong Li. "Dynamic miRNA Landscape Links Mammary Gland Development to the Regulation of Milk Protein Expression in Mice." Animals 12, no. 6 (March 14, 2022): 727. http://dx.doi.org/10.3390/ani12060727.
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Mammary gland morphology varies considerably between pregnancy and lactation status, e.g., virgin to pregnant and lactation to weaning. Throughout these critical developmental phases, the mammary glands undergo remodeling to accommodate changes in milk production capacity, which is positively correlated with milk protein expression. The purpose of this study was to investigate the microRNA (miRNA) expression profiles in female ICR mice’s mammary glands at the virgin stage (V), day 16 of pregnancy (P16d), day 12 of lactation (L12d), day 1 of forced weaning (FW1d), and day 3 of forced weaning (FW3d), and to identify the miRNAs regulating milk protein gene expression. During the five stages of testing, 852 known miRNAs and 179 novel miRNAs were identified in the mammary glands. Based on their expression patterns, the identified miRNAs were grouped into 12 clusters. The expression pattern of cluster 1 miRNAs was opposite to that of milk protein genes in mammary glands in all five different stages. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the predicted target genes of cluster 1 miRNAs were related to murine mammary gland development and lactation. Furthermore, fluorescence in situ hybridization (FISH) analysis revealed that the novel-mmu-miR424-5p, which belongs to the cluster 1 miRNAs, was expressed in murine mammary epithelial cells. The dual-luciferase reporter assay revealed that an important milk protein gene—β-casein (CSN2)—was regarded as one of the likely targets for the novel-mmu-miR424-5p. This study analyzed the expression patterns of miRNAs in murine mammary glands throughout five critical developmental stages, and discovered a novel miRNA involved in regulating the expression of CSN2. These findings contribute to an enhanced understanding of the developmental biology of mammary glands, providing guidelines for increasing lactation efficiency and milk quality.
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Ilkbahar, YN, G. Thordarson, IG Camarillo, and F. Talamantes. "Differential expression of the growth hormone receptor and growth hormone-binding protein in epithelia and stroma of the mouse mammary gland at various physiological stages." Journal of Endocrinology 161, no. 1 (April 1, 1999): 77–87. http://dx.doi.org/10.1677/joe.0.1610077.
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Increasing evidence suggests that GH is important in normal mammary gland development. To investigate this further, we studied the distribution and levels of growth hormone receptor (GHR) and GH-binding protein (GHBP) in the mouse mammary gland. At three weeks of age, the epithelial component of the right fourth inguinal mammary gland of female mice was removed. These animals were then either maintained as virgins until they were killed or they were mated. One group of the mated mice was killed on day 18 of pregnancy and the remaining mated animals were allowed to carry their pups until term and were killed on day 6 of lactation. At the time of death, both the intact left and the de-epithelialized right mammary glands were collected from all three groups. Some of the intact glands served as a source of epithelial cells, free of stroma. The mRNA levels for GHR and GHBP were measured in intact glands, epithelia-cleared fat pads, and isolated mammary epithelial cells. GHR and GHBP mRNAs were expressed in both the mammary epithelium and stroma. However, the levels of both GHR and GHBP mRNAs were significantly higher in the stroma as compared with the epithelium component. This increase for both mRNAs was from 3- to 12-fold at each physiological state examined. In the intact gland, both GHR and GHBP transcripts were highest in virgins, declined during late pregnancy, and the lowest levels were found in the lactating gland. GHBP and GHR protein concentrations were also assessed in intact glands and epithelia-free fat pads. Similar to the mRNAs, GHR and GHBP protein levels (means+/-s.e.m.) in intact glands were highest in virgin mice (0.891+/-0.15 pmoles/mg protein and 0.136+/-0.26 pmoles/mg protein respectively), declined during late pregnancy (0. 354+/-0.111 pmoles/mg protein and 0.178+/-0.039 pmoles/mg protein respectively), and were lowest during lactation (0.096+0.037 pmoles/mg protein and 0.017+0.006 pmoles/mg protein respectively). Immunocytochemistry utilizing specific antisera against mouse (m) GHR and mGHBP revealed that the two proteins are localized to both the stroma and parenchyma of mouse mammary glands, with similar patterns of immunostaining throughout the different physiological stages analyzed. GHR immunolocalized to the plasma membrane and cytosol of mammary epithelial cells and adipocytes, whereas the GHBP immunostaining was nuclear and cytosolic. In conclusion, we report here that GHR and GHBP mRNAs and proteins are expressed in both the epithelium and the stroma of mammary glands of virgin, pregnant, and lactating mice. In intact glands, GHR and GHBP proteins, as well as their transcripts are higher in abundance in virgin relative to lactating mice. At all physiological stages, GHR and GHBP mRNA levels are higher in the stroma compared with the parenchyma. These findings indicate that the actions of GH in the mammary gland are both direct through its binding to the epithelia, and indirect by binding to the stroma and stimulation of IGF-I production which, in turn, affects mammary epithelial development.
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Lee, Sungin, Seulji Lee, Aeri Lee, Hun Ju Sim, Geon A. Kim, Byung-Jae Kang, and Wan Hee Kim. "The Presence and Distribution of TRPM7 in the Canine Mammary Glands." Animals 10, no. 3 (March 11, 2020): 466. http://dx.doi.org/10.3390/ani10030466.
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The transient receptor potential melastatin-subfamily member 7 (TRPM7) cation channel is a bifunctional ion channel with intrinsic kinase activity and is ubiquitously expressed in the animal/human body. Accumulated knowledge of TRPM7 suggests that it plays an essential role in normal physiological processes, including the development, survival, proliferation, differentiation, and migration of cells. The aim of this study was to demonstrate the presence and expression patterns of TRPM7 in normal canine mammary glands using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry. Normal mammary gland tissue samples were obtained from five female beagle dogs. RT-PCR and sequencing of the amplified PCR products demonstrated the presence of TRPM7 mRNA in normal mammary glands, and the presence of TRPM7 protein was confirmed by Western blotting. Immunohistochemical investigations demonstrated the expression of TRPM7 in the apical membrane of acinar and ductal epithelial cells in the canine mammary glands. These results provide the first evidence of the presence and distribution of TRPM7 in the canine mammary gland and could help explain the physiological and pathological roles of TRPM7 in the canine mammary gland; however, additional studies are required to elucidate these roles.
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Golchin, Diba, Farhang Sasani, Mir Sepehr Pedram, and Zohreh Khaki. "Clinicopathological Diversity and Epidemiological Aspects of Canine and Feline Mammary Gland Tumors in Tehran: A Survey (2020-2022)." Iranian Journal of Veterinary Medicine 17, no. 3 (July 1, 2023): 231–42. http://dx.doi.org/10.32598/ijvm.17.3.1005291.
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Background: Mammary tumors are common in dogs and cats. They are models for investigating carcinogenesis and designing treatment protocols that benefit human beings. Senescence, sex, and reproductive status affect the development of such neoplasms. Objectives: In Iran’s absence of a national animal tumor registry, the present study determined clinicopathological and epidemiological aspects of canine and feline mammary tumors in referral cases of four veterinary practices across Tehran from 2020 to 2022. Here, the incidence and types of canine and feline mammary tumors are described, in addition to sex, reproductive status, age, breed, the affected mammary gland(s), grades, lymphatic invasion, and lymph node metastases. Methods: All canine and feline patients with masses in the mammary gland region were considered in this study. The resected tumors and occasional lymph nodes were macroscopically scrutinized. Hematoxylin-Eosin slides were reviewed by light microscopy and immunohistochemistry was utilized when necessary. Results: Of the 76 dogs and eight cats, 100% were females, and the majority were intact. Most patients were 10-11 years old. Purebreds were the most frequent referrals. In some patients, more than one mammary gland had developed neoplasm, i.e. 141 affected glands in 76 bitches and nine affected glands in eight queens. Tumors were presented in both chains and even on the ventral midline, with an increased preponderance of caudally located glands. Thus, the caudal-most glands, i.e. inguinal and caudal abdominal glands, constituted 31.2% and 66.7% of the affected glands in bitches and queens, respectively. Intraductal papillary carcinoma (17%) and complex carcinoma (16.3%) had the highest incidence in dogs. The most commonly observed lesions in cats were lobular hyperplasia with atypia, and duct ectasia, each encompassing 22.3% of the affected glands. Most canine neoplasms were grade I (90.3%), while grade II neoplasms had the highest incidence in cats (50%). Lymphatic invasion and lymph node metastases were seen in canine anaplastic carcinoma, solid carcinoma, and complex carcinoma, as well as feline comedocarcinoma and tubular carcinoma. Conclusion: The risk of developing malignant tumors increases as the individual ages, and generally, caudally located mammary glands in intact purebred females are at increased risk. Moreover, anaplastic carcinomas must be precisely examined, both clinically and histopathologically, for lymph node metastases.
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Gladenko, Svitlana. "Ultrasound examination of mammary glands in patients with infertility on background violations of menstrual function." Perinatology and reproductology: from research to practice 3, no. 3 (September 25, 2023): 44–51. http://dx.doi.org/10.52705/2788-6190-2023-03-6.
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The objective. Іs to investigate the state of the mammary glands in patients with infertility of endocrine genesis. Materials and methods. The study was conducted in 110 patients with endocrine infertility who underwent an ultrasound examination of the mammary glands. The first group (n=52) consisted of patients with a regular menstrual cycle against the background of luteal phase insufficiency, the second group (n=58) consisted of patients with a menstrual cycle disorder with anovulation. Statistical processing of the research results was carried out using the standard programs "Microsoft Excel 5.0" and "Statistica 8.0". Results and their discussion. Changes in the mammary glands according to the type of PCH in the studied group were found in 44 out of 110 patients (40.0%), underdevelopment of the structural elements of the mammary glands - in 19 out of 110 (17.3%), early involutional changes - in 6 out of 110 (65, 4%), focal formations – in 4 out of 110 (3.6%). The frequency of fibrocystic disease in patients of the II group was 1.3 times higher compared to the I group - 24 (41.3%) versus 20 (38.4%), respectively, p<0.01. At the same time, focal mammary gland formations of the fibroadenoma type were diagnosed 3.5 times more often in patients of the I group - 3 (5.8%) versus 1 (1.7%) in the II group, p<0,01. Conclusions. In infertility of endocrine genesis, the first place in the structure of mammary gland pathology is diffuse fibrocystic disease - 40.0%. The frequency of underdevelopment of mammary glands is 17.3%, early involutional changes 10.3%, and focal formations like fibroadenoma are 3.6% of cases.
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Mehta, R. G., T. A. Hultin, and R. C. Moon. "Metabolism of the chemopreventive retinoid N-(4-hydroxyphenyl)retinamide by mammary gland in organ culture." Biochemical Journal 256, no. 2 (December 1, 1988): 579–84. http://dx.doi.org/10.1042/bj2560579.
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N-(4-Hydroxyphenyl)retinamide (4-HPR) is considered to be the most effective chemopreventive retinoid for chemically induced mammary carcinogenesis in rats. However, the mechanism of 4-HPR action in mammary cells is poorly understood. In the present study we examined the metabolism of 4-HPR in the mouse mammary gland in organ culture. Mammary glands excised from BALB/c mice were incubated with 4-HPR in the presence of insulin, prolactin and steroid hormones for 6 days. The glands were extracted with chloroform/methanol (2:1, v/v), and the metabolites were separated on a reversed-phase h.p.l.c. column. Three metabolites were separated in addition to 4-HPR; one of the metabolites, M2, was co-eluted with 13-cis-4-HPR, M3 was co-eluted with N-(4-methoxyphenyl)retinamide (4-MPR) and M1 remains unidentified. There appeared to be some hormonal regulation in the distribution of metabolites in the glands. Increased levels of 4-MPR and M1 were observed in insulin-plus-prolactin-treated glands as compared with the glands incubated with steroid hormones. Furthermore, it was observed that M1 isolated from the livers of 4-HPR-treated rats competed for the cellular retinoic acid-binding protein (CRABP) sites; however, 4-HPR did not bind to CRABP. These results indicate that mouse mammary gland can metabolize 4-HPR and that the metabolites which compete for CRABP sites may have physiological significance in the retinoid inhibition of mammary carcinogenesis.
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Akter, Mst, and Md Alam. "Regional mastectomy for mammary gland tumor in a bitch: A case report." Veterinary Research Notes 2, no. 12 (2022): 86. http://dx.doi.org/10.5455/vrn.2022.b19.
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Objective: Mammary gland tumors are the most prevalent neoplasm in bitches. This study focuses on the diagnosis and surgical treatment of gland tumors in a bitch that has not been spayed. Materials and Methods: A 4-year-old female dog weighing 8 kg with a history of big, firm swelling around the left third and fourth mammary glands was presented. This tumor grew quickly and doubled in size in just a few weeks. After a thorough clinical evaluation, it became obvious that this was a case of a tumor of the mammary gland. The tumor mass wassurgically excised from the mammary glands (mastectomy) after the appropriate restraint, aseptic procedure, and anesthetic protocol. A histological examination of the tumor tissue was carried out to confirm the diagnosis. Results: The dog healed up satisfactorily after surgery, and there was no sign of complications or recurrence during a 2-year observation. Following surgical manipulation, a positive clinical result was achieved. After 2 years, there was no evidence of tumor recurrence. Conclusion: Although most canine glandular tumors develop in the mammary glands, early detection and proper surgery may be the most effective solution.
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Nikolenko, D. E. "HISTOGENESIS AND MOLECULAR PECULIARITIES OF TERMINAL DUCT IN THE WOMAN'S MAMMARY GLANDS." Актуальні проблеми сучасної медицини: Вісник Української медичної стоматологічної академії 21, no. 3 (November 16, 2021): 201–7. http://dx.doi.org/10.31718/2077-1096.21.3.201.
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The development of a woman's mammary glands occurs during the fertile age. It is during this period that the glands are subject to morpho-functional changes in the form of proliferation and differentiation of the epithelium in the parenchyma and elements of the stroma as response to the action of many stimulating physiological factors of the body. There changes have a tendency to be repeated several times during the woman's reproductive age. There is enough in-depth knowledge about the object of the cyclic effect of sex hormones in the woman's mammary glands. This study will expand knowledge about the important morphological state of the terminal ducts of the mammary glands before pregnancy and childbirth that can be of great importance in determining the histogenesis of possible pathomorphological changes in the gland of a dyshormonal and neoplastic nature. The aim of the study was to investigate the molecular characteristics of the parenchyma of the terminal ducts of the mammary glands of a non-pregnant woman of reproductive age. The study was carried out on autopsy material of 192 micro-incisions of breast tissue samples from 8 women who died of infectious diseases. Karyometry with the definition of the logarithm of the volume of the nuclei of the parenchymal elements in the structures of the terminal ducts was performed; histological, histochemical and immunohistochemical research methods were applied. The study identified histogenetic series of the epithelial lining in the parenchyma of the terminal ducts of the mammary gland; applying immunohistochemical markers enabled cytotyping of the epithelial elements of these ducts, as well revealing certain functions of the terminal ducts of the mammary glands before pregnancy and childbirth.
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Mogus, Joshua Philip. "Exposure to the Endocrine Disruptor, Propylparaben, During Pregnancy and Lactation, Alters Typical Parity-Induced Reorganization of the Mouse Mammary Gland." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A487—A488. http://dx.doi.org/10.1210/jendso/bvab048.997.
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Abstract The mammary gland is a hormone sensitive organ that is susceptible to endocrine disrupting chemicals (EDCs) during several vulnerable periods, including pregnancy and lactation. Mammary gland reorganization during pregnancy and lactation is hormone driven and provides long-term protection against breast cancer risk. It is unknown if EDC exposures during these sensitive windows can alter mammary reorganization to either enhance or offset parity-induced protection against breast cancer. Here, we examined effects of propylparaben (PP), a common preservative used in personal care products and foods with estrogen receptor (ER) agonist properties, on the parous mouse mammary gland. Pregnant BALB/c mice were treated with 0, 20, 100, or 10,000 µg/kg/day PP throughout pregnancy and lactation. These doses were selected for their relevance to human exposures. We also included an unexposed nulliparous female group to evaluate the typical changes associated with parity. Five weeks post-involution (and five weeks after the last PP exposure), mammary glands were collected and assessed for changes in histomorphology, hormone receptor expression, immune cell number, and gene expression. We found that PP reduced many of the typical morphological effects of parity on the mammary gland, resulting in intermediate phenotypes for ductal density and total epithelial structures. Notably, we found increased proliferation in PP-treated mammary glands, despite decreased ductal epithelial volume relative to parous controls. Mammary glands from PP-treated females also had alterations in the expression of ERα-mediated genes, including PgR (the gene that encodes progesterone receptor) and Igf1, with expression levels that were intermediate to both nulliparous and parous control mice. Finally, PP reduced the effect of parity on several immune cell types in the mammary gland including B cells, T-cells, and M2 macrophages. These results suggest that PP, at levels relevant to human exposure, can disrupt the normal response to parity in the mouse mammary gland, including persistent alterations to mammary gland structures. Future studies should address whether PP exposures disturb the protective effects of pregnancy on mammary cancer risk.
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STELWAGEN, K., B. W. McBRIDE, D. G. GRIEVE, and R. A. TOWNER. "NUCLEAR MAGNETIC RESONANCE IMAGING AND PROTON SPECTROSCOPY USED AS A TECHNIQUE TO ASSESS MAMMARY GLAND COMPOSITION IN HOLSTEIN HEIFERS." Canadian Journal of Animal Science 70, no. 4 (December 1, 1990): 1151–54. http://dx.doi.org/10.4141/cjas90-141.
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Mammary glands of eight nonpregnant, nulliparous Holstein heifers (416 ± 11 d) were used to study the potential for nuclear magnetic resonance (NMR) imaging and proton spectroscopy as a technique to assess mammary gland composition. It was concluded that the NMR technique has the potential to quantitate mammary gland composition in heifers. Key words: Nuclear magnetic resonance imaging and spectroscopy, mammary composition, Holstein heifers
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Zinser, Glendon, Kathryn Packman, and JoEllen Welsh. "Vitamin D3 receptor ablation alters mammary gland morphogenesis." Development 129, no. 13 (July 1, 2002): 3067–76. http://dx.doi.org/10.1242/dev.129.13.3067.
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Postnatal mammary gland morphogenesis is achieved through coordination of signaling networks in both the epithelial and stromal cells of the developing gland. While the major proliferative hormones driving pubertal mammary gland development are estrogen and progesterone, studies in transgenic and knockout mice have successfully identified other steroid and peptide hormones that impact on mammary gland development. The vitamin D3 receptor (VDR), whose ligand 1,25-dihydroxyvitamin D3 is the biologically active form of vitamin D3, has been implicated in control of differentiation, cell cycle and apoptosis of mammary cells in culture, but little is known about the physiological relevance of the vitamin D3 endocrine system in the developing gland. In these studies, we report the expression of the VDR in epithelial cells of the terminal end bud and subtending ducts, in stromal cells and in a subset of lymphocytes within the lymph node. In the terminal end bud, a distinct gradient of VDR expression is observed, with weak VDR staining in proliferative populations and strong VDR staining in differentiated populations. The role of the VDR in ductal morphogenesis was examined in Vdr knockout mice fed high dietary Ca2+ which normalizes fertility, serum estrogen and neonatal growth. Our results indicate that mammary glands from virgin Vdr knockout mice are heavier and exhibit enhanced growth, as evidenced by higher numbers of terminal end buds, greater ductal outgrowth and enhanced secondary branch points, compared with glands from age- and weight-matched wild-type mice. In addition, glands from Vdr knockout mice exhibit enhanced growth in response to exogenous estrogen and progesterone, both in vivo and in organ culture, compared with glands from wild-type mice. Our data provide the first in vivo evidence that 1,25-dihydroxyvitamin D3 and the VDR impact on ductal elongation and branching morphogenesis during pubertal development of the mammary gland. Collectively, these results suggest that the vitamin D3 signaling pathway participates in negative growth regulation of the mammary gland.
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Fowler, Paul A., Christopher H. Knight, and Margaret A. Foster. "Omitting the dry period between lactations does not reduce subsequent milk production in goats." Journal of Dairy Research 58, no. 1 (February 1991): 13–19. http://dx.doi.org/10.1017/s002202990003346x.
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SummaryFour goats were studied from the end of their second lactation. One mammary gland of each goat was dried off just prior to the start of the third gestation, whilst the other gland was milked throughout gestation, with no dry period. At the end of gestation the continuously milked gland was significantly smaller than the gland that had been allowed a dry period. However, this difference did not persist beyond parturition and there was no significant difference between the milk yields of the two glands in the next lactation, although the continuously milked gland tended to have the higher yield. At 18 weeks of lactation, mammary parenchyma weight and secretory cell number were significantly greater in the continuously milked gland, but mammary enzyme activities did not differ between the two glands.
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Lang, Limin, Jisong Zheng, Shuyi Liang, Fenglin Zhang, Yiming Fu, Kaixin Deng, Fan Li, et al. "Browning of Mammary Fat Suppresses Pubertal Mammary Gland Development of Mice via Elevation of Serum Phosphatidylcholine and Inhibition of PI3K/Akt Pathway." International Journal of Molecular Sciences 24, no. 22 (November 10, 2023): 16171. http://dx.doi.org/10.3390/ijms242216171.
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Mammary fat plays a profound role in the postnatal development of mammary glands. However, the specific types (white, brown, or beige) of adipocytes in mammary fat and their potential regulatory effects on modulating mammary gland development remain poorly understood. This study aimed to investigate the role of the browning of mammary fat on pubertal mammary gland development and explore the underlying mechanisms. Thus, the mammary gland development and the serum lipid profile were evaluated in mice treated with CL316243, a β3-adrenoceptor agonist, to induce mammary fat browning. In addition, the proliferation of HC11 cells co-cultured with brown adipocytes or treated with the altered serum lipid metabolite was determined. Our results showed that the browning of mammary fat by injection of CL316243 suppressed the pubertal development of mice mammary glands, accompanied by the significant elevation of serum dioleoylphosphocholine (DOPC). In addition, the proliferation of HC11 was repressed when co-cultured with brown adipocytes or treated with DOPC. Furthermore, DOPC suppressed the activation of the PI3K/Akt pathway, while the DOPC-inhibited HC11 proliferation was reversed by SC79, an Akt activator, suggesting the involvement of the PI3K/Akt pathway in the DOPC-inhibited proliferation of HC11. Together, the browning of mammary fat suppressed the development of the pubertal mammary gland, which was associated with the elevated serum DOPC and the inhibition of the PI3K/Akt pathway.
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Eivani, D., and P. Mortazavi. "The relationship between basal and luminal cytokeratins with histopathologic characteristics of canine mammary gland cancer." Polish Journal of Veterinary Sciences 19, no. 2 (June 1, 2016): 261–69. http://dx.doi.org/10.1515/pjvs-2016-0033.
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Abstract Neoplasia occurs mostly in mammary glands in female dogs and mammary gland cancer is one of the causes of death in these animals cytokeratins are one of the most important of tumor markers for identification of tumor prognosis. In this study, 120 canine malignant tumor samples of mammary glands were studied. From each sample, a section was taken for hematoxylin-eosin staining and two sections for immunohistochemical staining of markers CK5/6 and CK7. Histopathology slides was evaluated by light microscope. The results show that the presence of markers CK7 and CK5/6 had no significant relationship with tumor grade and type (p<0.05). However, it seems that unlike humans, CK5/6 and CK7 is not an independent prognostic factor in canine mammary gland tumors.
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Zhao, Yan, Carina Johansson, Thai Tran, Ryan Bettencourt, Yoko Itahana, Pierre-Yves Desprez, and Stephen F. Konieczny. "Identification of a Basic Helix-Loop-Helix Transcription Factor Expressed in Mammary Gland Alveolar Cells and Required for Maintenance of the Differentiated State." Molecular Endocrinology 20, no. 9 (September 1, 2006): 2187–98. http://dx.doi.org/10.1210/me.2005-0214.
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Abstract The development of mammary glands relies on complicated signaling pathways that control cell proliferation, differentiation, and apoptotic events through transcriptional regulatory circuits. A key family of transcription factors used in mammary gland development is the helix-loop-helix/basic helix-loop-helix (HLH/bHLH) protein family. In this study, we identify Mist1 as a tissue-restricted Class II bHLH transcription factor expressed in lactating mammary glands. Mouse and human mammary glands accumulated Mist1 protein exclusively in secretory alveolar cells, and Mist1 transcripts were differentially expressed in mouse SCp2 cells induced to differentiate by addition of lactogenic hormones. Mist1 null (Mist1KO) lactating mammary glands were defective in normal lobuloalveolar organization, exhibiting shedding of cells into the alveolus lumen and premature activation of the signal transducer and activator of transcription 3 signaling pathway. These cells also failed to maintain expression of the gap junction proteins connexin26 and connexin32, leading to the loss of gap junctions. Our findings suggest that loss of Mist1 impairs the maintenance of the fully differentiated alveolar state and, for the first time, places Mist1 within the hierarchy of known HLH/bHLH proteins that control mammary epithelial cell development.
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Choudhary, Ratan K., Shanti Choudhary, Devendra Pathak, Rahul Udehiya, Ramneek Verma, Sandeep Kaswan, Arpan Sharma, Dhiraj Gupta, Mrigank Honparkhe, and Anthony V. Capuco. "Evaluation of xanthosine treatment on gene expression of mammary glands in early lactating goats." Journal of Dairy Research 85, no. 3 (August 2018): 288–94. http://dx.doi.org/10.1017/s0022029918000493.
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This study examined the hypothesis that xanthosine (XS) treatment would promote mammary-specific gene expression and stem cell transcripts and have a positive influence on milk yield of dairy goats. Seven primiparous Beetal goats were assigned to the study. Five days after kidding, one gland (either left or right) was infused with XS (TRT) twice daily for 3 d and the other gland with no XS infusion served as a control (CON). Mammary biopsies were collected at 10 d and RNA was isolated. Gene expression analysis of milk synthesis genes, mammary stem/progenitor cell markers, cell proliferation and differentiation markers were performed using real time quantitative PCR (RT-qPCR). Results showed that the transcripts of milk synthesis genes (BLG4, CSN2, LALBA, FABP3, CD36) and mammary stem/progenitor cell markers (ALDH1 and NR5A2) were increased in as a result of XS treatment. Average milk yield in TRT glands was increased marginally (approximately ~2% P = 0·05, paired t-test) per gland relative to CON gland until 7 wk. After 7 wk, milk yield of TRT and CON glands did not differ. Analysis of milk composition revealed that protein, lactose, fat and solids-not-fat percentages remained the same in TRT and CON glands. These results suggest that XS increases expression of milk synthesis genes, mammary stem/progenitor cells and has a small effect on milk yield.
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CHOUDHARY, RATAN KUMAR, DEVENDRA PATHAK, SHANTI CHOUDHARY, and RAMNEEK VERMA. "Immunolocalization of estrogen alpha and progesterone beta receptors in goat mammary gland." Indian Journal of Animal Sciences 88, no. 4 (April 17, 2018): 420–27. http://dx.doi.org/10.56093/ijans.v88i4.78803.
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Steroid receptors particularly estrogen receptor alpha and progesterone receptor beta are essential for mammary gland development. Objective of this study was to explore transcript and protein expression profile of steroid receptors in goat mammary glands. A varied expression of ER-alpha and PR-B was observed during lactation, nonlactating/ dry, mastitic and mammary pre-cancer/cancer in goats. During lactation, immunopositivity of ER-alpha was observed only in the nuclei of mammary epithelial cells (MEC) and stromal cells. However, in non-lactating stage, ER-alpha immunopositivity was observed both in nucleus and cytoplasm of MEC. In mammary pre-cancer (based on aberrant expression of CD10, FNDC3B and MUC1) immunoreactivity of ER-alpha (38±12.5%) varied from non-lactating (14.8±3.1%) and lactating (7.9±2.6%) glands. During naturally infected mastitis, a reduction in the expression of ER-alpha and PR-B was observed.We observed similar expression patterns of ER-alpha and PR-B as that of their protein expression. Transcripts of these receptors were highest in mammary precancer. In comparison to lactating glands, expressions of ER-alpha and PR-B was upregulated in mammary precancers by 17- folds and 9.2-folds, respectively. These results showed a reduction in expression of steroid receptors in mastitic glands and upregulation in mammary precancer indicating role of these receptors in cell proliferation.
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Kim, Globinna, Jong Geol Lee, Seung-A. Cheong, Jung-Min Yon, Myeong Sup Lee, Eui-Ju Hong, and In-Jeoung Baek. "Progesterone receptor membrane component 1 is required for mammary gland development†." Biology of Reproduction 103, no. 6 (September 11, 2020): 1249–59. http://dx.doi.org/10.1093/biolre/ioaa164.
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Abstract The physiological functions of progesterone (P4) in female reproductive organs including the mammary glands are mediated via the progesterone receptor (PR), but not all P4 functions can be explained by PR-mediated signaling. Progesterone receptor membrane component 1 (PGRMC1), a potential mediator of P4 actions, plays an important role in the ovary and uterus in maintaining female fertility and pregnancy, but its function in mammary glands has not been elucidated. This study investigated the role of PGRMC1 in mouse mammary gland development. Unlike in the uterus, exogenous estrogen (E2) and/or P4 did not alter PGRMC1 expression in the mammary gland, and Pgrmc1-knockout (KO) mice displayed reduced ductal elongation and side branching in response to hormone treatment. During pregnancy, PGRMC1 was expressed within both the luminal and basal epithelium and gradually increased with gestation and decreased rapidly after parturition. Moreover, although lactogenic capacity was normal after parturition, Pgrmc1 KO resulted in defective mammary gland development from puberty until midpregnancy, while the expression of PR and its target genes was not significantly different between wild-type and Pgrmc1-KO mammary gland. These data suggest that PGRMC1 is essential for mammary gland development during puberty and pregnancy in a PR-independent manner.
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Warmadewi, I. Gusti Ayu Intan, Ni Made Rai Suarni, and Ni Wayan Sudatri. "HISTOLOGICAL OF MICE MAMMAL GLANDS THAT SUPPLEMENTATION WITH INFUSE WATER OF MANIHOT ESCULENTA LEAVES." SIMBIOSIS 11, no. 2 (September 25, 2023): 197. http://dx.doi.org/10.24843/jsimbiosis.2023.v11.i02.p07.
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Phytoestrogens are plant compounds whose structure and properties are similar to estrogens. Flavonoids are one of the phytoestrogen compounds and cassava leaves are known to contain flavonoid compounds. This study was conducted to determine the effect of steeping cassava leaves on the histology of the mammary glands of female mice. This study used a completely randomized design (CRD) which consisted of 4 treatments and 6 replications. The treatment consisted of K0 as a control given 0.5 mL/bb/day of distilled water, P1 given 0.5 mL of cassava leaves steeped with a concentration of 7%, P2 given 0.5 mL of cassava leaves steeped at a concentration of 9%, P3 which was given a decoction of cassava leaves 0.5 mL with a concentration of 11% for 21 days. On the 22nd day, surgery was performed, then the mammary glands of the mice were taken to make histological incisions. Histological incisions of the mice's mammary glands were made using the paraffin method and hematoxylyn-eosin staining and observed under a microscope with 100x magnification with the help of optilab and the image raster program. Parameters observed included the number of mammary gland alveoli, the number of mammary gland ducts, and the diameter of the mammary gland ducts. The data obtained was analyzed statistically with the SPSS series 23 for Windows program. If the results of the analysis show a significant difference, then continue with the Duncan test. The results showed that steeping cassava leaves significantly increased the average number of alveoli, number of ducts and duct diameter of the mammary glands of female mice. The most influential dose of steeped cassava leaves was the dose of 9 g/Kg BW of female mice.
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Wang, Rui-An, Ratna K. Vadlamudi, Rozita Bagheri-Yarmand, Iwan Beuvink, Nancy E. Hynes, and Rakesh Kumar. "Essential functions of p21-activated kinase 1 in morphogenesis and differentiation of mammary glands." Journal of Cell Biology 161, no. 3 (May 5, 2003): 583–92. http://dx.doi.org/10.1083/jcb.200212066.
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Although growth factors have been shown to influence mammary gland development, the nature of downstream effectors remains elusive. In this study, we show that the expression of p21-activated kinase (Pak)1, a serine/threonine protein kinase, is activated in mammary glands during pregnancy and lactation. By targeting an ectopic expression of a kinase-dead Pak1 mutant under the control of ovine β-lactoglobulin promoter, we found that the mammary glands of female mice expressing kinase-dead Pak1 transgene revealed incomplete lobuloalveolar development and impaired functional differentiation. The expression of whey acidic protein and β-casein and the amount of activated Stat5 in the nuclei of epithelial cells in transgenic mice were drastically reduced. Further analysis of the underlying mechanisms revealed that Pak1 stimulated β-casein promoter activity in normal mouse mammary epithelial cells and also cooperated with Stat5a. Pak1 directly interacted with and phosphorylated Stat5a at Ser 779, and both COOH-terminal deletion containing Ser 779 of Stat5a and the Ser 779 to Ala mutation completely prevented the ability of Pak1 to stimulate β-casein promoter. Mammary glands expressing inactive Pak1 exhibited a reduction of Stat5a Ser 779 phosphorylation. These findings suggest that Pak1 is required for alveolar morphogenesis and lactation function, and thus, identify novel functions of Pak1 in the mammary gland development.
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Marettová, E., and M. Maretta. "Immunohistochemical Study of the Stromal Cells in the Lactating Bovine Mammary Gland." Folia Veterinaria 62, no. 3 (September 1, 2018): 29–35. http://dx.doi.org/10.2478/fv-2018-0024.
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Abstract The bovine mammary gland is a special gland characterized by high secretory activity. During lactation the cellular and fibrous components of the interstitial tissue septa are exposed to store accumulated secretory products. The aim of this study was to find and study the cells in the stroma of the bovine lactating mammary gland. For this purpose, the immunohistochemical methods and antibodies against the smooth muscle actin, vimentin, and desmin were used. The myoepithelial cells (MEC) which stained with smooth muscle actin (SMA), were found supporting the secretory units and the intralobular ducts. Coexpression of the SMA and desmin were found in the smooth muscle cells of the blood vessels. The fibroblasts (myofibroblasts) and free cells positive to vimentin were located in the connective tissue septa. The results of this study on the mammary glands indicated that smooth muscle cells (SMC) were altered in the lactating mammary gland, with additional cells such as fibroblasts (myofibroblasts) participated in the storage and after milk let-down they allowed the mammary glands to return to their original state.
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Pedchenko, VK, and W. Imagawa. "Estrogen treatment in vivo increases keratinocyte growth factor expression in the mammary gland." Journal of Endocrinology 165, no. 1 (April 1, 2000): 39–49. http://dx.doi.org/10.1677/joe.0.1650039.
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Proliferation and differentiation of mammary epithelia are regulated by the combined action of systemic hormones and locally derived paracrine growth factors. Keratinocyte growth factor (KGF) is a potential candidate stromal factor that may participate in the hormonal control of stromal/epithelial interactions. In this study, we have examined the in vivo effect of 17beta-estradiol (E) treatment on KGF expression in mammary glands of peripubertal (5-week-old) and mature (11-week-old) mice. Mice received subcutaneous injections of hormone after which KGF mRNA levels were assayed by ribonuclease protection analysis of mammary gland RNA. E treatment caused a dose- and time-dependent increase in KGF mRNA levels in intact mice from both age groups. Neither 17alpha-estradiol nor progesterone injection affected KGF mRNA levels. Comparison of the relative expression of KGF in parenchyma-free fat pads and in intact glands demonstrated that the basal and E-dependent KGF mRNA levels did not require the presence of mammary epithelium. ELISA assay of KGF tissue content demonstrated that concomitantly with an up-regulation of mRNA, E treatment also increased KGF protein in mammary glands from peripubertal and mature mice. These data show that E treatment stimulates both KGF mRNA and protein expression in mammary stroma in vivo and raises the possibility that KGF has a role in E-regulated mammary gland development.
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Berryhill, Grace E., Julia M. Gloviczki, Josephine F. Trott, Jana Kraft, Adam L. Lock, and Russell C. Hovey. "In Utero Exposure to trans-10, cis-12 Conjugated Linoleic Acid Modifies Postnatal Development of the Mammary Gland and its Hormone Responsiveness." Journal of Mammary Gland Biology and Neoplasia 26, no. 3 (September 2021): 263–76. http://dx.doi.org/10.1007/s10911-021-09499-y.
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AbstractWe previously showed that dietary trans-10, cis-12 conjugated linoleic acid (10,12 CLA) stimulates estrogen-independent mammary growth in young ovariectomized mice. Here we investigated the effects of in utero or postnatal exposure to cis-9, trans-11 (9,11 CLA) and 10,12 CLA on postnatal development of the mammary gland and its responsiveness to ovarian steroids. In the first experiment we fed dams different CLA prior to and during gestation, then cross fostered female pups onto control fed dams prior to assessing the histomorphology of their mammary glands. Pregnant dams in the second experiment were similarly exposed to CLA, after which their female pups were ovariectomized then treated with 17β-estradiol (E), progesterone (P) or E + P for 5 days. In a third experiment, mature female mice were fed different CLA for 28 days prior to ovariectomy, then treated with E, P or E + P. Our data indicate that 10,12 CLA modifies the responsiveness of the mammary glands to E or E + P when exposure occurs either in utero, or postnatally. These findings underline the sensitivity of the mammary glands to dietary fatty acids and reinforce the potential for maternal nutrition to impact postnatal development of the mammary glands and their risk for developing cancer.
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Maunsell, Fiona P., Dawn E. Morin, Peter D. Constable, Walter L. Hurley, and Gene C. McCoy. "Use of mammary gland and colostral characteristics for prediction of colostral IgG1 concentration and intramammary infection in Holstein cows." Journal of the American Veterinary Medical Association 214, no. 12 (June 15, 1999): 1817–23. http://dx.doi.org/10.2460/javma.1999.214.12.1817.
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Objective To determine whether mammary gland or colostral characteristics at calving could be used to predict colostral immunoglobulin G1 (IgG1) concentration or intramammary infection (IMI) and whether leakage of colostrum affects IgG1 concentration. Design Prospective study. Animals 113 multiparous Holstein cows. Procedure Cows were examined within 3 hours of calving, and mammary gland and colostral characteristics, colostral volume, somatic cell count, and concentrations of IgG1, fat, and protein were determined. Bacteriologic culture of mammary secretions was performed approximately 14 and 7 days before calving and at calving. Associations of gland and colostral characteristics with colostral IgG1 concentration, colostral volume, and IMI were examined. Results Thick or thin colostrum had higher IgG1 concentration than colostrum of intermediate viscosity. Colostrum from mammary glands that were firm had low IgG1 concentration. Colostral IgG1 concentration was weakly correlated with volume. Intramammary infection was likely to be detected if colostrum contained clots or blood or if the California Mastitis Test (CMT) score was ≥ 2. Somatic cell count was higher for glands with IMI than for uninfected glands, and CMT score was correlated with cell count. Clinical Implications Mammary gland and colostral characteristics were of little value in predicting IgG1 concentration. Our findings do not support recommendations that first milking colostrum that is thin (watery) or that is from cows producing large volumes not be fed to dairy calves. Colostral characteristics, particularly CMT score, were of value for predicting IMI. (J Am Vet Med Assoc 1999;214:1817-1823)
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Miller, James L., Alexandra Reddy, Rebecca M. Harman, and Gerlinde R. Van de Walle. "A xenotransplantation mouse model to study physiology of the mammary gland from large mammals." PLOS ONE 19, no. 2 (February 28, 2024): e0298390. http://dx.doi.org/10.1371/journal.pone.0298390.
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Although highly conserved in structure and function, many (patho)physiological processes of the mammary gland vary drastically between mammals, with mechanisms regulating these differences not well understood. Large mammals display variable lactation strategies and mammary cancer incidence, however, research into these variations is often limited to in vitro analysis due to logistical limitations. Validating a model with functional mammary xenografts from cryopreserved tissue fragments would allow for in vivo comparative analysis of mammary glands from large and/or rare mammals and would improve our understanding of postnatal development, lactation, and premalignancy across mammals. To this end, we generated functional mammary xenografts using mammary tissue fragments containing mammary stroma and parenchyma isolated via an antibody-independent approach from healthy, nulliparous equine and canine donor tissues to study these species in vivo. Cryopreserved mammary tissue fragments were xenotransplanted into de-epithelialized fat pads of immunodeficient mice and resulting xenografts were structurally and functionally assessed. Preimplantation of mammary stromal fibroblasts was performed to promote ductal morphogenesis. Xenografts recapitulated mammary lobule architecture and contained donor-derived stromal components. Mammatropic hormone stimulation resulted in (i) upregulation of lactation-associated genes, (ii) altered proliferation index, and (iii) morphological changes, indicating functionality. Preimplantation of mammary stromal fibroblasts did not promote ductal morphogenesis. This model presents the opportunity to study novel mechanisms regulating unique lactation strategies and mammary cancer induction in vivo. Due to the universal applicability of this approach, this model serves as proof-of-concept for developing mammary xenografts for in vivo analysis of virtually any mammals, including large and rare mammals.
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Cinti, Saverio. "Reversible physiological transdifferentiation in the adipose organ." Proceedings of the Nutrition Society 68, no. 4 (August 24, 2009): 340–49. http://dx.doi.org/10.1017/s0029665109990140.
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All mammals are provided with two distinct adipose cells, white and brown adipocytes. White adipocytes store lipids to provide fuel to the organism, allowing intervals between meals. Brown adipocytes use lipids to produce heat. Previous descriptions have implied their localization in distinct sites of the body; however, it has been demonstrated that they are present together in many depots, which has led to the new concept of the adipose organ. In order to explain their coexistence the hypothesis of reversible physiological transdifferentiation has been developed, i.e. they are contained together because they are able to convert, one into the other. In effect, if needed the brown component of the organ could increase at the expense of the white component and vice versa. This plasticity is important because the brown phenotype of the organ is associated with resistance to obesity and its related disorders. A new example of reversible physiological transdifferentiation of adipocytes is offered by the mammary gland during pregnancy, lactation and post-lactation stages. The gravidic hormonal stimulus seems to trigger a transdifferentiation of adipocytes into milk-producing and secreting epithelial glands. In the post-lactation period some of the epithelial cells of the mammary gland seem to transdifferentiate into adipocytes. Recent unpublished results suggest that explanted adipose tissue, as well as explanted isolated mature adipocytes, is able to transdifferentiate into glands with epithelial markers of milk-secreting mammary glands. These findings, if confirmed, seem to suggest new windows into the cell biology frontiers of adipocytes.
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Ormerod, E. Jane, and Philip S. Rudland. "Regeneration of mammary glands in vivo from isolated mammary ducts." Development 96, no. 1 (July 1, 1986): 229–43. http://dx.doi.org/10.1242/dev.96.1.229.
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Rat mammary ducts, free of buds, can alone regenerate complete mammary trees when transplanted into the interscapular fat pads of syngeneic host rats. All the main mammary cell types are identified within such outgrowths. Epithelial cells, which show the presence of milk fat globule membrane antigens and microvilli on their luminal surfaces, line the ducts. Basal cells surrounding the ducts show characteristic features of myoepithelial cells: immunoreactive actin and keratin within the cytoplasm, myofilaments, pinocytotic vesicles and hemidesmosomal attachments to the basement membrane. Cells within the end buds and lateral buds, however, show few if any cytoplasmic myofilaments and are relatively undifferentiated in appearance. Intermediate morphologies between these cells and myoepithelial cells are seen nearer the ducts. In this respect they exactly resemble the cap cells found in terminal end buds (TEBs) of normal mammary glands. Occasional epithelial cells within alveolar buds show the presence of immunoreactive casein, which is a product of secretory alveolar cells in the normal rat mammary gland. Dissected terminal end buds can regenerate similar ductal outgrowths. Thus, ductal tissue alone can generate all the major mammary cell types seen in the normal gland, including the cap cells.
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Davis, Felicity M., Agnes Janoshazi, Kyathanahalli S. Janardhan, Natacha Steinckwich, Diane M. D’Agostin, John G. Petranka, Pooja N. Desai, et al. "Essential role of Orai1 store-operated calcium channels in lactation." Proceedings of the National Academy of Sciences 112, no. 18 (April 20, 2015): 5827–32. http://dx.doi.org/10.1073/pnas.1502264112.
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The nourishment of neonates by nursing is the defining characteristic of mammals. However, despite considerable research into the neural control of lactation, an understanding of the signaling mechanisms underlying the production and expulsion of milk by mammary epithelial cells during lactation remains largely unknown. Here we demonstrate that a store-operated Ca2+ channel subunit, Orai1, is required for both optimal Ca2+ transport into milk and for milk ejection. Using a novel, 3D imaging strategy, we visualized live oxytocin-induced alveolar unit contractions in the mammary gland, and we demonstrated that in this model milk is ejected by way of pulsatile contractions of these alveolar units. In mammary glands of Orai1 knockout mice, these contractions are infrequent and poorly coordinated. We reveal that oxytocin also induces a large transient release of stored Ca2+ in mammary myoepithelial cells followed by slow, irregular Ca2+ oscillations. These oscillations, and not the initial Ca2+ transient, are mediated exclusively by Orai1 and are absolutely required for milk ejection and pup survival, an observation that redefines the signaling processes responsible for milk ejection. These findings clearly demonstrate that Ca2+ is not just a substrate for nutritional enrichment in mammals but is also a master regulator of the spatiotemporal signaling events underpinning mammary alveolar unit contraction. Orai1-dependent Ca2+ oscillations may represent a conserved language in myoepithelial cells of other secretory epithelia, such as sweat glands, potentially shedding light on other Orai1 channelopathies, including anhidrosis (an inability to sweat).
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Hillerton, J. Eric, Christopher H. Knight, Alan Turvey, Stephen D. Wheatley, and Colin J. Wilde. "Milk yield and mammary function in dairy cows milked four times daily." Journal of Dairy Research 57, no. 3 (August 1990): 285–94. http://dx.doi.org/10.1017/s0022029900026935.
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SummaryGroups of lactating cows and heifers were milked four times daily in two diagonally opposed glands for 4 weeks, and the effects on milk yield studied relative to twice-daily milked glands as controls. Mammary enzyme activities, in vitro synthesis rates of milk constituents and histological scoring were determined in mammary biopsy samples obtained at the end of this period. These were used for assessment of mammary function. Frequent milking increased milk yield only in the treated glands, the contralateral control glands continuing to decline in yield at ~ 2%/week. There was no significant difference in response between cows and heifers; the mean increase in yield was 10·4%. The rate of decline in milk yield tended to decrease with frequent milking, to ~ 1%/week. Consequently the yield of the treated glands continued to be elevated above that of the controls for some time after reversion to overall twice daily milking. Milk protein content was increased slightly by frequent milking. Mammary enzyme activities were ~ 18% higher in the treated glands than in the controls. Synthesis rates of lactose, casein and total protein were unaffected by milking frequency, but were all lower in the gland selected for the second biopsy, reflecting the reduction in milk yield caused by the first biopsy. DNA synthesis was increased by milking frequency, as were the size and number of epithelial cells in histological sections.