Background: Cyclophosphamide is the most widely used alkylating agent in the treatment of haematological malignancies. On the other hand, cyclophosphamide has adverse effects on the fertility of both sexes. Aim of the work: The present work was done to study the histological and stereological changes in the developing ovary of the albino rat after a period of treatment with cyclophosphamide and the effect of rehabilitation after stopping the drug. Materials and Methods: Thirty-six immature female rats (newborn, one week, two weeks, oneand-half month and two-and-half month) were used in this study. They were subdivided into two groups. The control group (n=24) was injected intraperitoneally with dextrose 5%. The experimental group (n= 12) at the age of two weeks, received 100mg/ kg body weight cyclophosphamide intraperitoneally once weekly for four successive weeks. At the end of the treatment period this group was subdivided into two subgroups: subgroup A (treated group) including the rats at the age of one-andhalf month and subgroup B (rehabilitated group) including the rats at the age of two-and-half month which received the same drug regimen, but sacrificed after another four weeks without treatment. The specimens of all age groups were processed and stained with Heamatoxylin and Eosin. Other specimens at the age of one-and-half month were processed for semi-thin and ultra-thin examination. In the two age groups (control and treated) morphometeric measurements were performed. Results: The study showed shrinkage with decrease in the number and the size of the antral follicles, apoptosis and disorganization in the granulosa cell layers. Ultrastucturally, the most important feature observed was the fragmentation and leakage of the cellular nuclear materials of the granulosa cells and their clumping in the antrum. Morphometeric measurements showed a very highly significant reduction in the average follicular and oocytic diameter of the antral follicles and in the number of the healthy antral follicles while there was high significant reduction in the number of atretic antral follicles. In the rehabilitated group the follicles were less affected. Oocytes were affected in both groups; they were either vacuolated or totally absent. Morphometeric measurements showed highly significant reduction of the average oocytic diameter and in the average number of the granulosa cell layers.

Background: Excess fluorides intake produces histopathological changes of many organs. Methionine is a potential natural antioxidant against oxidative radicals. Aim of the Work: To evaluate the possible protective role of methionine against sodium fluoride (NaF)-induced pancreatic toxicity. Material and Methods: Thirty 3-months (200-250gm) adult male albino rats were divided into three equal groups: group I (control), group II (Fluoride group) and group III (Fluoride+methionine group). Control group; was given 1ml distilled water. Fluoride group; was given 10 mg NaF/kg b.w. Fluoride+methionine group; was given 10 mg NaF/kg b.w. and 2 mg methionine/rat. All the treatment was given orally by gastric tube once daily for 35 days. After anesthesia, all groups were sacrificed. The pancreatic specimens were prepared for light and electron microscopic studies and anti-insulin antibody immunohistochemical staining. The mean numbers of zymogen granules and insulin positive β-cells of all groups were counted. Results: The mean numbers of zymogen granules and insulin positive β-cells of the fluoride group were significantly decreased when compared to control. The pancreatic specimens of the fluoride group revealed congested blood vessels, extravasated blood cells, vacuolated pancreatic acini, loss of the acinar cell architecture, dilated rough endoplasmic reticulum and degenerated mitochondria. By anti-insulin antibodies immunohistochemistry, there was a weak positive reactivity in the fluoride treated group when compared to control. The concomitant administration of NaF and methionine improved these changes. Conclusion: The concurrent administration of NaF and methionine ameliorates the structural alterations developed in the pancreas following excess NaF intake.

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INTRODUCTIONCigarette smoking is considered the most prevalent type of substance dependence, causing serious public health-related problems worldwide. Nicotine is the main chemical substance in cigarettes with cognitive-enhancing effects that make it hard to quit smoking (Valentine and Sofuoglu, 2018; Fowler et al., 2020). Many brain imaging reports have shown activation of the brain centers responsible for attention and working memory performance after nicotine exposure (Rose et al., 2003). Nicotine also acts as an agonist in presynaptic nicotinic acetylcholine receptors, thus facilitating the synaptic release of several neurotransmitters (Singer et al., 2004).

TCs are suggested to play roles in tissue structural support, homeostasis maintenance, intercellular signaling, cell differentiation, immune surveillance, stem/progenitor cell guiding and nursing, and to participate in different tissue AbstractBackground:Many researches on telocytes (TCs) have proved its existence, structure and specific immune markers expression in many normal organs and in different species. Multiple physiologic functions have been suggested for these cells.Objectives: This study is designed to evaluate age-related changes ofTCs in different age groups in the renal tissue.Materials and Methods: 18 male Sprague-Dawley rats were used in this study and divided equally into 3 groups (each consists of 6 rats); Group I (rats aged 3 weeks), Group II (rats aged 3 months, adult) and Group III (rats aged one year). All rats of group I, II and III were sacrificed and each group was divided into two subgroups. The first subgroup was processed for light microscopic and immunohistochemical staining. The second subgroup was processed for electron microscopy. Morphometric and statistical studies were conducted.Results: TCs with their characteristic long and thin cytoplasmic projections (telopodes, Tps) are detected in each of H&E stained and CD34 immunostained sections. In group III, there is a significant reduction of the TCs count. TEM examination of the ultrathin sections revealed shrinkage of TCs with disintegration and fragmentation of the Tps with a significant reduction of the number of Tps arising from each TC in group III. In all groups of the study, homocellular and heterocellular junctions are observed. Conclusion:On comparison of the age groups in the study, it is proved that TCs decrease in number with degenerative changes observed with aging.