Academic literature on the topic 'Non-hairy skin'

Purpose: Azelaic acid is a natural keratolytic, comedolytic, and antibacterial drug that is used to treat acne. The topical application of azelaic acid is associated with problems such as irritation and low permeability. For dissolving, the problem is that microemulsion (ME) is used as a drug carrier. The aim of this study was to increase the azelaic acid affinity in the follicular pathway through ME. Methods: Azelaic acid-loaded MEs were prepared by the water titration method. The properties of the MEs included formulation stability, particle size, drug release profile, thermal behavior of MEs, the diffusion coefficient of the MEs and skin permeability in the non-hairy ear skin and hairy abdominal skin of guinea pig were studied in situ. Results: The MEs demonstrated a mean droplet size between 5 to 150 nm. In the higher ratios of surfactant/co-surfactant, a more extensive ME zone was found. All MEs increased the azelaic acid flux through both hairy and non-hairy skin compared with an aqueous solution of azelaic acid as a control. This effect of the ME was mainly dependent on the droplet diffusion coefficient and hydrodynamic radius. MEs with a higher diffusion coefficient demonstrated higher azelaic acid flux through hairy and non-hairy skin. Drug flux through both skins was affected by the surfactant/co-surfactant ratio in that the higher ratio increased the azelaic acid affinity into the follicular pathway. Conclusion: Finally, the ME with the highest droplet diffusion coefficient and the lowest surfactant/co-surfactant ratio was the best ME for azelaic acid delivery into the follicular pathway.

AbstractObjectiveThe objective of this study was to test if offset analgesia could be evoked using a noncontact thermal stimulator. Offset analgesia [J. Neurophysiol. 87:2205–2208, 2002] is defined as an unproportionally large decrease in pain intensity following a slight decrease in stimulation intensity. The importance of differences in thermal properties between human hairy and glabrous skin was investigated.MethodsA 20W diode laser (970 nm) was used for the thermal stimulation. A fast (50 images/s) infrared camera measured the skin temperature and a temperature controlled feedback control loop adjusted the laser power. 8 subjects participated in this study. Stimulations were applied on the dorsum side and in the palm of the hand. Subjects were instructed to continuously rate the pain intensity. First the subject was stimulated using both a rising 35–45 °C staircase and a decreasing 45–35 °C staircase in both skin types; each staircase step was 1 °C and lasted for 15 s. Offset analgesia was tested by stimulating the hairy skin on the dorsum of the hand using two sequential temperature plateaus (48–48 °C, 48–49 °C, 49–48 °C and 49–49 °C). Each plateau was held for 5 s.ResultsFor the staircase stimulations identical surface temperatures were perceived significantly higher in glabrous than in hairy skin (p < 0.001). The offset analgesia test showed that a decrease in temperature from 49 to 48 °C evoked a drop in the pain rating which was significantly lower than observed during a 48–48 °C stimulation (p < 0.001) indicating offset analgesia.ConclusionA non-contact thermal stimulator is able to evoke offset analgesia. Furthermore, it was noted that a high penetration laser causes higher pain ratings in glabrous skin than in hairy skin—a relationship which is opposite to low penetration lasers (CO2 laser) and contact heat stimulation.

We contrasted the physiology and peripheral targets of subclassified nociceptive and nonnociceptive afferents that express acid-sensing ion channel (ASIC)–like currents. The threshold for current activation was similar in eight distinct cell subclasses regardless of functional modality (pH 6.8). When potency was determined from concentration–response curves, nonnociceptors exhibited currents with significantly greater potency than that of all but one class of nociceptors (pH50 = 6.54 and 6.75 vs. 6.20–6.34). In nonnociceptive cells, acid transduction was also confined to a very narrow range (0.1–0.3 vs. 0.8–1.4 pH units for nociceptors). Simultaneous whole cell recording and ratiometric imaging of three peptidergic nociceptive classes were consistent with the expression of Ca2+-permeable ASICs. Sensitivity to psalmotoxin and flurbiprofen indicated the presence of Ca2+-permeable ASIC1a. Immunocytochemistry on these subclassified populations revealed a differential distribution of five ASIC proteins consistent with Ca2+ permeability and differential kinetics of proton-gated currents (type 5: ASIC1a, 1b, 2a, 2b, 3; type 8a: ASIC1a, 1b, 3; type 8b: ASIC1a, 1b, 2a, 2b, 3). Using DiI tracing, we found that nociceptive classes had discrete peripheral targets. ASIC-expressing types 8a and 9 projected to hairy skin, but only types 8a and 13 projected to glabrous skin. Non-ASIC–expressing types 2 and 4 were present only in hairy skin. We conclude that ASIC-expressing nociceptors differ from ASIC-expressing nonnociceptors mainly by range of proton reactivity. ASIC- as well as non-ASIC–expressing nociceptors have highly distinct cutaneous targets, and only one class was consistent with the existence of a generic C polymodal nociceptor (type 8a).

Vibrotactile interfaces are an inexpensive and non-invasive way to provide performance feedback to body-machine interface users. Interfaces for the upper extremity have utilized a multi-channel approach using an array of vibration motors placed on the upper extremity. However, for successful perception of multi-channel vibrotactile feedback on the arm, we need to account for vibration propagation across the skin. If two stimuli are delivered within a small distance, mechanical propagation of vibration can lead to inaccurate perception of the distinct vibrotactile stimuli. This study sought to characterize vibration propagation across the hairy skin of the forearm. We characterized vibration propagation by measuring accelerations at various distances from a source vibration of variable intensities (100–240 Hz). Our results showed that acceleration from the source vibration was present at a distance of 4 cm at intensities >150 Hz. At distances greater than 8 cm from the source, accelerations were reduced to values substantially below vibrotactile discrimination thresholds for all vibration intensities. We conclude that in future applications of vibrotactile interfaces, stimulation sites should be separated by a distance of at least 8 cm to avoid potential interference in vibration perception caused by propagating vibrations.

Abstract Chronic lymphocytic leukemia and other B-cell malignancies have been associated with melanoma and non-melanoma skin cancers (NMSC). However, an analysis of Surveillance, Epidemiology and End Results (SEER) data from 1973-2007 found that hairy cell leukemia (HCL), while associated with an increased second cancer risk overall, was not associated with melanoma. In addition, the incidence of NMSC in HCL patients has not been described to our knowledge. Per recent SEER data, the median age at melanoma diagnosis in the general population was 61 years with an age-adjusted incidence rate of 0.02%/year. Methods We identified 372 patients seen at Memorial Sloan-Kettering Cancer Center (MSKCC) over the past 30 years (1983-2013) with a morphologic diagnosis of HCL. Of these, we found 267 patients with ≥2 months of follow-up. We examined the medical records of these 267 patients for demographic data, treatment with purine analogs (PA), and co-occurring skin cancers, including melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC). Skin cancers were considered to be “co-occurring” if they were diagnosed up to 1 year before or any time after the diagnosis of HCL. Results In this 267 patient cohort, the median age at HCL diagnosis was 52.1 years (range 19.6-86.1), and the vast majority of patients were white, non-Hispanic males [Table 1]. 225 patients (84%) were treated with a PA, either cladribine or pentostatin. Of 267 patients, 34 (12.7%) developed skin cancer: 11 (4.1%) melanoma and 25 (9.4%) NMSC [Table 2]. Twelve patients had SCC and 22 BCC. Eleven of 34 patients (32%) had >1 type of skin cancer: 9 BCC and SCC, 1 BCC and melanoma, and 1 SCC and melanoma.For the 34 patients with skin cancer, median follow-up from HCL diagnosis was 10 years (0.7-33.6), median age at HCL diagnosis was 57.5 years, and almost all patients were white, non-Hispanic males. Twenty-nine of the 34 patients (85%) received a PA. Nine patients (27%) either did not receive or were diagnosed with skin cancer before PA therapy. Eighteen patients (53%) were diagnosed with skin cancer between 1 year before and 5 years after HCL; 16 patients (47%) were diagnosed >5 years after HCL. Conclusions In 267 HCL patients with very long follow-up, we found a high incidence of all skin cancers (12.7%), melanoma (4.1%), and NMSC (9.4%). Furthermore, the risk of melanoma appears to be considerably higher in the HCL cohort than the general population (0.02%/year). Although these groups were not age, sex, or race-matched, both HCL and melanoma typically occur in white individuals, and one might expect the risk of melanoma to be lower in HCL patients if there was no association given that HCL usually presents at a younger age. Although a previous analysis of SEER data did not show an association between HCL and melanoma, many of these data were collected before PA therapy was introduced. Moreover, almost all melanoma patients in our cohort were previously treated with a PA, possibly explaining the increased risk. The pathogenesis of this apparent association is elusive, but immunosuppression induced by PA therapy in addition to inherent immunosuppression from HCL itself may be responsible. There also appears to be an increased risk of NMSC in our cohort; however, the precise incidence of NMSC in the general population is not available for comparison to our knowledge. Our findings reinforce that HCL patients should be screened aggressively for skin cancer, particularly given the risk of synchronous melanoma. Disclosures: No relevant conflicts of interest to declare.

Background: It is not unusual for oral manifestations to occur in dermatological diseases. The aim of this study was to observe and evaluate oral manifestations in patients diagnosed with dermatological diseases. Methods: A cross-sectional study based on a convenient sampling technique was conducted among patients with dermatological conditions who visited the polyclinic of King Faisal University Polyclinic of Al-Ahsa, Saudi Arabia from Sep-Nov 2021. Results: Sixty-one percent were females, 50% were aged >30 years, 77% had higher education, 61% were unemployed, 82% were non-smokers, and 20% had some medical conditions. 14.5% suffered from immune-mediated skin disease, 25.3% had eczema, 21.7% showed dermatitis infections, 3.6% had Genodermatosis, 9.6% were with psoriasis and other keratinizing disorders, and 25.3% had miscellaneous skin conditions. 85.5% of skin patients did not have any oral manifestations; oral lesions were of perioral dermatitis (1.2%), melanotic macule (1.2%), fissured tongue (2.4%), oral lichen planus (2.4%), mucocele (2.4%), and one case of each with geographic tongue, herpes labialis, and hairy tongue. Practical ImplicationsThis study highlights the importance of integration of oral health into general health for management of oral diseases associated with other body diseases. Conclusion: The majority of the patients in this study sample with skin diseases did not show any oral manifestations. More females and aged patients had more skin conditions. Keywords: Prevalence, Oral manifestations, Dermatological conditions, Cross-sectional study

Background. Trichotillomania is one of the topical problems in dermatovenerology. Annually the number of people who visit dermatologists with hair loss problem is increasing and makes up to 8–10% in structure of dermatologic illnesses.Clinical Case Description. There are patients with primary psychiatric disorders in practice of dermatologist. This disorders are accompanied by self-injurious behavior and secondary skin changes and/or its appendages. We are performing clinical survey of trichotillomania of hairy part of the head, onychophagy, trichophagy with following developing of trichobezoar in teenage girl. To treat this girl we have carried out surgical operation. Later we have performed complex drug and non-drug treatment under control of pediatric psychiatrist, psychotherapist and dermatologist. The prognosis and perspectives of pathologic process development have been estimated. Possible etiology, clinical signs and dermatological aspects of diagnosis and treatment of disease were discussed.Conclusion. This clinical case has to draw attention of dermatovenerologists, paediatricians, psychiatrists to the problem of factitial dermatitis.

1. Localized cortical cooling was employed in anesthetized cats for the rapid reversible inactivation of the distal forelimb region within the primary somatosensory cortex (SI). The aim was to examine the responsiveness of individual neurons in the second somatosensory area (SII) in association with SI inactivation to evaluate the relative importance for tactile processing of the direct thalamocortical projection to SII and the indirect projection from the thalamus to SII via an intracortical path through SI. 2. Response features were examined quantitatively before, during, and after SI inactivation for 29 SII neurons, the tactile receptive fields of which were on the glabrous or hairy skin of the distal forelimb. Controlled mechanical stimuli that consisted of l-s trains of either sinusoidal vibration or rectangular pulses were delivered to the skin by means of small circular probes (4- to 8-mm diam). 3. Twenty-three of the 29 SII neurons (80%) showed no change in response level (in impulses per second) as a result of SI inactivation. These included seven neurons activated exclusively or predominantly by Pacinian corpuscle (PC) receptors, six that received hair follicle input, four activated by convergent input from hairy and glabrous skin, and six driven by dynamically sensitive but non-PC inputs from the glabrous skin. 4. Six SII neurons (20%), also made up of different functional classes, displayed a reduction in response to cutaneous stimuli when SI was inactivated. 5. Stimulus-response relations, constructed by plotting response level in impulses per second against the amplitude of the mechanical stimulus, showed that the effect of SI inactivation on individual neurons was consistent over the whole response range. 6. The reduced response level seen in 20% of SII neurons in association with SI inactivation cannot be attributed to direct spread of cooling from SI to the forelimb area of SII, as there was no evidence for a cooling-induced prolongation in SII spike waveforms, an effect that is known to precede any cooling-induced reduction in responsiveness. 7. As SI inactivation produced a fall in spontaneous activity in the affected SII neurons, we suggest that the inactivation removes a source of background facilitatory influence that arises in SI and affects a small proportion of SII neurons. 8. Phase-locking and therefore the precision of impulse patterning were unchanged in the responses of SII neurons to vibration during SI inactivation. This was the case whether response levels of neurons were reduced or unchanged by SI inactivation.(ABSTRACT TRUNCATED AT 400 WORDS)