Biomedical subjects
Publications and source records attributed to Mohamed A Adly.
Melatonin is a free-radical scavenger and antioxidant. Roentgen irradiation of testis (animal model formed of albino rats) was associated with destruction and depletion of the germinal epithelial cells. In roentgen-irradiated, melatonin-pretreated animals, these changes were markedly ameliorated. Thus administration of melatonin before irradiation can protect testis from some of the destructive effects of roentgen irradiation.
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BACKGROUND: Heat shock protein (HSP) is a molecular chaperone involved in protein folding, assembly, and transport and in the regulation of cell growth and differentiation. HSP27 protein is expressed in murine hair follicle (HF) and in human skin during fetal development. In this investigation we hypothesized that HSP27 protein is expressed in the human scalp skin and its expression in HF changes with the transitions form anagen --> catagen --> telogen stages. METHODS: To test this hypothesis, the immunoreactivity of HSP27 protein was examined in human scalp skin by immunofluorescent method. A total of 50 normal human scalp skin biopsy specimens were examined (healthy women, age 53-57 years). In each case, 50 HF were analyzed (35, 10, and 5 follicles in anagen, catagen, and telogen, respectively). RESULTS: HSP27 protein expression was prominent in human scalp anagen, and weak in both catagen and telogen HFs. Within HF, HSP27 protein immunoreactivity was prominent in the outer root sheath, inner root sheath, precorteocytes, and corteocytes of the hair shaft. In addition, HSP27 protein expression was prominent in the epidermis, sebaceous glands, sweat glands, and arrector pili muscles. LIMITATIONS: Only some types of heat shock proteins are known to date. Also, our knowledge about the exact molecular mechanisms involved in the interactions among these protein and other molecular chaperones is still incomplete. CONCLUSIONS: Our investigation reports, for the first time, the expression patterns of HSP27 in human scalp skin and HF. The differential expression of HSP27 during HF cycling suggests its possible roles in human HF biology.
Irradiation has profound effects on the reproductive function. Our knowledge about radioprotective effects of melatonin against X-ray-induced testis damage is rudimentary. In this investigation, we hypothesized that melatonin can minimize germ-cell depletion and morphological features of cell damage in testis following X-ray irradiation (XRI). To examine these effects, and to test our hypothesis, an animal model comprised of 60 Albino rats was established. The animals were divided into five groups: Group 1, non-irradiated; Group 2, X-ray irradiated (XRI, 8 Grays); Group 3, XRI pretreated with solvent (ethanol and phosphate-buffered saline); Group 4, non-irradiated group treated with melatonin and Group 5, XRI pretreated with melatonin. The testes were evaluated for both histological (light microscopy) and ultrastructural changes (transmission electron microscopy). Histologically, there were marked depletions (66%) of the germinal epithelial cells, in XRI group (Groups 2 and 3), whereas these changes were almost absent in XRI testis of animals pretreated with melatonin (Group 5). The number of spermatogenic cells in XRI testis of animals pretreated with melatonin (Group 5) was comparable (95%) to that of non-irradiated group (Groups 1 and 4) but significantly (P < 0.05) higher than those in XRI testis (34%, Groups 2 and 3). Ultrastructurally, XRI testis (Groups 2 and 3) showed features of apoptosis (condensation of the nuclei, vacuolization of the cytoplasm, increased cytoplasmic density and apoptotic bodies). These features were absent in XRI testis of animals pretreated with melatonin (Group 5). Also, this Group showed features of an increased metabolic activity (large acrosomal vesicle, prominent Golgi, increased mitotic activity, increased complement of cytoplasmic organelles and appearance of nucleoli-like bodies). There was a minimal depletion of the Sertoli and Leydig cells following XRI. Also, morphological features of apoptosis were infrequent in these cells. Administration of melatonin (MEL) prior to irradiation can protect testis against its destructive effects. The protective effects include amelioration of germ-cell depletion and apoptotic changes. The clinical ramifications of these observations mandate further studies.
BACKGROUND: Nerve growth factor (NGF) and its high-affinity receptor, tyrosine kinase A (TrkA), are members of the neurotrophin family. NGF-TrkA are involved in murine hair morphogenesis and cycling. To date, their expression in human hair follicle (HF) is unknown. In this investigation, we hypothesize that NGF-TrkA proteins are expressed in the human scalp skin. Moreover, NGF-TrkA expression in HF changes with the transitions from anagen-->>catagen-->>telogen stages. MATERIALS AND METHODS: To test our hypothesis and to fill this existing gap in literature, the immunostaining values (semiquantitative evaluation of protein expression: SI, staining intensity; PP, percentage of positive cells; and IR score, immunoreactivity score) of NGF and TrkA proteins were examined in human scalp skin by immunofluorescent and immunoperoxidase staining methods. Fifty normal human scalp skin biopsy specimens were examined (healthy females, 53-57 years). In each case, 50 HFs were analyzed (35, 10, and five follicles in anagen, catagen, and telogen, respectively). RESULTS: The IR scores were statistically significantly higher (p < 0.001) in anagen as compared with either catagen or telogen HF (9.61 +/- 0.12 vs. 1.4 +/- 0.10 vs. 0.6 +/- 0.10 for NGF and 3.31 +/- 0.02 vs. 0.5 +/- 0.10 vs. 0.2 +/- 0.10 for TrkA). In the anagen HF, high expression values were seen in the distal region, followed by upper distal, lower distal, and bulb regions for both NGF (10.6 +/- 0.21 vs. 10.3 +/- 0.21 vs. 9.2 +/- 0.40 vs. 8.1 +/- 0.30) and TrkA (3.54 +/- 0.07 vs. 3.45 +/- 0.07 vs. 3.31 +/- 0.06 vs. 3.13 +/- 0.04). Both NGF and TrkA proteins showed prominent expression in the melanocytes (7.6 +/- 0.15 vs. 2.50 +/- 0.07), keratinocytes (10.2 +/- 0.40 vs. 2.71 +/- 0.06), sebaceous glands (10.2 +/- 0.40 vs. 2.72 +/- 0.06), and sweat glands (10.4 +/- 0.40 vs. 2.84 +/- 0.05). CONCLUSIONS: Our findings report, for the first time, the expression pattern of NGF and TrkA proteins in human scalp skin and HF. The differential expression of these proteins during HF cycling suggests their possible roles in human HF biology. The clinical ramifications of these observations mandate further investigations.
BACKGROUND: Glial cell line-derived neurotrophic factor (GDNF) and a related family member, neurturin (NTN), as well as their cognate receptors (GDNF receptors, GFRalpha-1 and GFRalpha-2, respectively) are involved in nervous system development and murine hair cycle control. To date, their expression in human scalp skin is still unknown. MATERIALS AND METHODS: The expression pattern of these proteins was examined in human scalp skin by immunofluorescence and immunoalkaline phosphatase staining methods as well as RT-PCR (GDNF). A total of 50 normal human scalp skin biopsy specimens were examined (healthy females, 53-57 years). RESULTS: The expression of GDNF protein was strong in the epidermis and sebaceous and sweat glands. In the epidermis, GDNF protein expression was seen in all layers except the stratum corneum. It was strong in the basal layer and decreased gradually towards the granular layer. The results of RT-PCR analysis revealed that GDNF protein is synthesised in the epidermis. The expression of NTN, GFRalpha-1, and GFRalpha-2 proteins was strong in the papillary dermis and sebaceous and sweat glands. In the epidermis, NTN protein expression was absent. The expression of GFRalpha-1 and GFRalpha-2 proteins was moderate in the epidermis. The expression of c-Ret protein was consistently strong in the epidermis and sebaceous and sweat glands. These proteins were strongly expressed in both epithelial and mesenchymal compartments of human anagen VI scalp hair follicles. CONCLUSIONS: Our investigation reports, for the first time, the expression patterns of GDNF, NTN, GFRalpha-1, GFRalpha-2, and c-Ret proteins in human scalp skin. The expression of these proteins in the skin suggests their possible roles in skin homeostasis. The clinical ramifications of these observations mandate further investigations. Adly MA, Assaf HA, Hussein MR, Paus R. Analysis of the expression pattern of glial cell line-derived neurotrophic factor, neurturin, their cognate receptors GFRalpha-1 and GFRalpha-2, and a common signal transduction element c-Ret in the human scalp skin.