Background: Aging has many effects on a person’s skin, from wrinkles and sags to increased risk of certain skin conditions, such as skin cancer. As people age, their skin begins to change due to environmental, genetic, nutrition and other factors.Objectives: Understand some of the changes that occur in aging skin including changes in the general morphological, histological and architectural arrangement, epidermal thickness, basement membrane and histochemical changes in melanocytes.Methods: Skin specimens were taken from the anterior abdominal wall of 30 human males at different ages. General histological preparation for paraffin blocks was performed and the blocks were sectioned at (5-6µ) and stained with H&E. S100 protein was used to demonstrate immunohistochemistry labeled melanocytes changes with age. Histometric measurement of epidermal thickness and basement membrane thickness, using eyepiece graticule was performed on these groups.Results: The young age group showed a uniform arrangement of cells in all stratums of the epidermis while the old age group showed diminished thickness of the epidermis. A significant difference between young- adult age group (A and B groups) and the old age group (C group) was recorded. The epithelial basement membrane thickness was increased with age significantly (P value ≤ 0.001). Melanocytes demonstration using S100 showed that these cells tend to be situated at the tips of rete pages, there number are generally low and didn't varied a lot between young and adult age groups. There was yet marked decline in the number of melanocytes in old age group.Conclusion: Aging as a process have a marked influences on skin morphology, thickness, cellularity and basement membrane.Key Words: Aging, skin, S100, morphometry and basement membrane

Aging --- skin --- S100 --- morphometry and basement membrane

Abstract: The objective of the current study was to determine the immunohistochemical distribution and density of prolactin secreting cells and Anti-S100 cells of the pituitary gland in rabbit, Oryctolagus cuniculus and guinea pig, Cavia porcellus. The Immunohistochemical study indicated that prolactin-secreting cells were arranged in single, double or triple groups in the rabbit pituitary gland while they were mostly single cells in guinea pig. In both animals PRL-secreting cells were polymorphic in shape with centric or acentric nucleus. The Anti S-100 cells were scattered in pairs distalis. The S-100 positive cells sometimes had cytoplasmic processes between endocrine cells. Although PRL-secreting cells represent high percentage (44%) in the rabbit. There was no significant increase with t-value 1.11 and the probability was more than 0.05. Anti S-100 cells significally increased (54%) in guinea pig with t-value 2.46 as compared with the rabbit and the probability less than 0.05.

الخلاصة:هدفت الدراسة الحالية لاحتساب توزيع وكثافة الخلايا الفارزة للبرولاكتين و الموجبة لبروتين oryctolagus cuniculus في الغدة النخامية لكل من الارنب وخنزير غينا. لقد اشارت الدراسة الى ان الخلايا الفارزة للبرولاكتين تنتظم على شكل تجمعات احادية وثنائية وثلاثية في الغدة النخامية للارنب بينما تنتظم على شكل تجمعات احادية غالبا في الغدة النخامية لخنزير غينيا. وكانت الخلايا الفارزة للبرولاكتين في كلا الحيوانين متعددة الشكل مع نواة مركزية او غير مركزية و كانت الخلايا الموجبة لبروتين S-100 لكلا الحيوانين منتشرة في الجزء القاصي والحدبي ولقد لوحظ ان الخلايا الموجبة لبروتين S-100 تمتلك احيانا بروزات سايتوبلازمية تمتد بين الخلايا الافرازية على الرغم من ان الخلايا الفارزة للبرولاكتين شكلت النسبة الاعلى في الارنب الا ان الخلايا الموجبة لبروتين S-100 قد ارتفعت معنويا في خنزير غينيا عند مقارنتها بالارنب.

: pituitary gland --- Immunohistochemical stains --- rabbit --- guinea pig --- PRL cells --- Anti-S100 cells