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Minute, pale tan macules of the esophageal mucosa observed at autopsy proved, on microscopical study, to be sebaceous glands unaccompanied by hair follicles. Metaplasia of pluripotent cells is postulated as their origin in this purely endodermal tissue, rather than derivation from islands of misplaced epidermis.
The effects of immobilization-induced stress on plasma testosterone levels and lipogenesis in the sebaceous gland were examined in male Syrian hamsters. To induce immobilization stress, the animals were placed in the prone position and wrapped with flexible steel wire gauze at room temperature. Plasma testosterone levels were determined by radioimmunoassay (RIA) of blood samples and sebaceous lipogenesis was determined by measurement of the incorporation of a lipid precursor, 14C-acetate, in ear skin biopsy samples. Both specimens were obtained immediately after the hamsters were decapitated. Immobilization stress for 4 consecutive days produced a marked fall in plasma testosterone levels and sebaceous lipogenesis. These reductions were reversible, the decreased plasma testosterone levels and decreased sebaceous lipogenesis recovering to the nonstressed or prestimulus levels after approximately 1 week. In 4-day stressed animals in occurrence with a decrease in plasma testosterone, sebaceous lipogenesis in ear with topical application of a small dose of testosterone, which have no effect on plasma testosterone level, was equivalent to that in nonstressed animals. These findings indicated that immobilization-induced stress lowered testosterone secretion, and consequently the testosterone levels in the skin, resulting in decreased lipogenesis in the skin. These results thus suggest that psychological or physiological stress can influence cutaneous function by inducing changes in the neuroendocrine system.
Most common scalp flaking disorders show a strong correlation with sebaceous gland (SG) activity. Early SG activity in the neonate results in microfloral colonization and cradle cap. After maternal hormonal control subsides, there is little SG activity until puberty, when the SG turns on under sex hormone control. When the SG activity increases, the present but low Malassezia population has a new food source and proliferates, resulting in the scalp itching and flaking common to greater than 50% of adults. Dry scalp flaking, dandruff, and seborrheic dermatitis are chronic scalp manifestations of similar etiology differing only in severity. The common etiology is a convergence of three factors: (1) SG secretions, (2) microfloral metabolism, and (3) individual susceptibility. Dandruff and seborrheic dermatitis (D/SD) are more than superficial stratum corneum disorders, including alteration of the epidermis with hyperproliferation, excess lipids, interdigitation of the corneal envelope, and parakeratosis. The pathogenic role of Malassezia in D/SD has recently been elucidated, and is focused on their lipid metabolism. Malassezia restricta and M. globosa require lipids. They degrade sebum, free fatty acids from triglycerides, consume specific saturated fatty acids, and leave behind the unsaturates. Penetration of the modified sebaceous secretions results in inflammation, irritation, and scalp flaking.
PURPOSE: To study the sebaceous tumors of eyelid/conjunctiva associated with Muir-Torre syndrome (MTS) and to determine the role of immunohistochemical markers (MSH2, mismatch repair gene) in the diagnosis of patients with MTS. METHODS: A retrospective, noncomparative case series of 5 patients diagnosed with MTS from our laboratory. We also reviewed all previously reported cases of sebaceous eyelid tumors with a visceral malignancy. RESULTS: Four of the 5 patients were men, with a mean age of 55 years (range, 41 to 76 years). Four of the 5 patients had gastrointestinal carcinoma. On histopathological examination, 4 of the 5 tumors were classified as sebaceous adenomas that exhibited a distinct lobular pattern with prominent basaloid cells at the periphery of the lobules. One tumor was classified as a well-differentiated sebaceous gland adenocarcinoma. The diagnosis of MTS in all 5 patients was made after the diagnosis of the eyelid lesions. Immunohistochemical stains showed a lack of MSH2 expression in two tumors, which is highly consistent with MTS. CONCLUSIONS: Muir-Torre syndrome should be considered in patients who develop sebaceous tumors of the ocular adnexa. Immunohistochemistry for MSH2 is a practical initial approach for screening MTS in patients with sebaceous tumors.
We report a case of ectopic ectodermal structures in the ectocervix of a 51-year-old female. Sebaceous glands and numerous abnormal hair follicles were present in the stroma of an otherwise normal cervix.
The expression of enzymes involved in leukotriene and prostaglandin signalling pathways, of interleukins 6 and 8 and of peroxisome proliferator-activated receptors in sebaceous glands of acne-involved facial skin was compared with those of non-involved skin of acne patients and of healthy individuals. Moreover, 5-lipoxygenase and leukotriene A(4) hydrolase were expressed at mRNA and protein levels in vivo and in SZ95 sebocytes in vitro (leukotriene A(4) hydrolase > 5-lipoxygenase), while 15-lipoxygenase-1 was only detected in cultured sebocytes. Cyclooxygenase-1 and cyclooxygenase-2 were also present. Peroxisome proliferator-activated receptors were constitutively expressed. Enhanced 5-lipoxygenase, cyclooxygenase 2 and interleukin 6 expression was detected in acne-involved facial skin. Arachidonic acid stimulated leukotriene B(4) and interleukin 6 release as well as prostaglandin E(2) biosynthesis in SZ95 sebocytes, induced abundant increase in neutral lipids and down-regulated peroxisome proliferator-activated receptor-alpha, but not receptor-gamma1 mRNA levels, which were the predominant peroxisome proliferator-activated receptor isotypes in SZ95 sebocytes. In conclusion, human sebocytes possess the enzyme machinery for functional leukotriene and prostaglandin pathways. A comprehensive link between inflammation and sebaceous lipid synthesis is provided.
Electron microscopic examination using tannic acid fixation strongly supported the view that lipid droplets in the normal human sebaceous gland originate from smooth-surfaced endoplasmic reticulum. A true limiting membrane was clearly detected around the lipid droplets in the incipient stages but was undetectable in mature droplets.
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Electron microscopic observations revealed for the first time a small number of active melanocytes synthesizing distinctive melanin-containing organelles (melanin granules)in the ducts and acini of human sebaceous glands.
Gerbils (Meriones unguiculatus), given N-methyl-N-nitrosourea iv once weekly for 15 weeks at doses related to the mean lethal dose, developed tumors of the species-specific midventral sebaceous gland. These neoplasms were more frequent in males than females and were histologically classified as sebaceous adenomas or carcinomas of varying differentiation.
Radiolabelled fatty acids, when injected intradermally into cattle skin, were largely incorporated into the triglyceride and phospholipid fractions of the sebaceous gland lipids. Linoleic acid was incorporated into the triglycerides to a greater extent than oleic or palmitic acids, whereas the phospholipids had a greater affinity for palmitic acid. The peak uptake of linoleic acid into the glandular triglyceride fraction was at about 61 hours compared with 52 hours and three hours for oleic and palmitic acids. Radioactively 14C labelled triglycerides appeared on the skin surface within one day of intradermal injection of 14C linoleic acid. At an ambient temperature of 20 degrees C, a single output-peak occurred at nine days while at 35 degrees C two peaks at four and eight to nine days were observed. From the data an estimate of 6.5 days for the mean storage time of sebum triglycerides in the hair follicle canal at 20 degrees C has been made.
PURPOSE: To highlight the recognition and diagnosis of Muir-Torre syndrome (MTS) in patients with sebaceous tumors of the eyelid/conjunctiva and to determine the role of immunohistochemical markers as a screening test in patients with Muir-Torre syndrome. DESIGN: Single interventional case report. METHODS: The clinical and family history was reviewed from the records of a 41-year-old man who had a sebaceous gland adenoma of the tarsal conjunctiva of the left upper eyelid. The lesion was completely excised and submitted for histopathologic examination. Immunohistochemical stains using an antibody to MSH2 were performed on the paraffin-embedded sections of the tumor. RESULTS: Histopathologic examination of the tumor showed a lobular pattern with basaloid cells at the periphery of the lobules with central areas of sebaceous differentiation. Immunohistochemical stains showed a lack of MSH2 expression in the tumor, which is highly consistent with MTS. CONCLUSIONS: Muir-Torre syndrome should be considered in patients initially seen with sebaceous tumors of the eyelid. Immunohistochemistry for MSH2 is a practical initial approach to screen for MTS in patients with sebaceous tumors.
Liquid scintillation counting and autoradiography were used to measure DNA synthesis (3H-TdR uptake and incorporation) by the epidermis and the sebaceous glands in mouse pinna skin. Using this approach it has been possible to show that a chalone-like inhibitor of DNA synthesis acts rapidly to restrict the flow of epidermal G1 cells into S-phase. The point of action within the cell cycle is probably at the G1-S phase 'boundary'. The technique described is sufficiently sensitive to be used for measuring small alterations in DNA synthesis in short-term experiments and for long-term experiments in which the size of the progenitor cell population is altered by systemic or topical administration of compounds influencing DNA synthesis.
The authors describe a 12-year-old boy with a peculiar presentation of preputial papular lesions similar to molluscum contagiosum. Histopathologic investigation revealed the presence of a sebaceous gland opening directly onto the surface and hyperplasia of the epithelium.
Topical application of the testosterone derivative 17alpha-propylandrost-4-en-17beta-ol-3-one (Win 17665) caused a dose-related regression of the hamster flank organ and guinea pig supracaudal gland in mature male animals. Histological examination confirmed that this action of Win 17665 was on the size of the hamster sebaceous glands and was reversible on cessation of treatment. Topical application of Win 17665 also counteracted flank organ stimulation by directly applied 5-alpha-dihydrotestosterone and 4-androstene-3,17-dione. Seminal vesicle weight was reduced after the repeated subcutaneous administration of 100 mg/kg of Win 17665 but not after repeated oral administration of 320 mg/kg or topical administration of 1 gm/kg of Win 17665.
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Explore the source record for details and available documents.