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.

Background: Diabetes mellitus is a major risk factor of cardiovascular disease. There is evidence that vitamin D decreases type 1 diabetes mellitus risk during early adulthood and improves insulin secretion and resistance in diabetic patients. Low vitamin D level was observed to increase the cardiovascular disease.Objectives: This study aimed to assess the protective effect of vitamin D on diabetic vascular damages in aorta.Materials and Methods: 40 adult male rats were randomly divided into: group I(control), group II (vitamin D), group III (diabetic) and group VI(diabetic plus Vitamin D)(n = 10 rats /each group). Injection of streptozotocin (60 mg/kg) as a single dose intraperitoneal to induce diabetes. Vitamin D was administered orally every other day in a dose of 12.5 mg/kg. After 12weeksof treatment period, aortic samples were collected for histological examination.Results: Morphological changes of aortic tissue in diabetic untreated group in the form of reduction of tunica media thickness and areas of tunica intima detachment. The elastic lamellae became irregular, fragmented or branched. Shrunken dark or lysed nuclei of smooth muscle fibers were seen in tunica media of diabetic group. The diabetic treated group with vitamin D showed more or less normal structure of the layers of aortic tissuewith comparable thickness to the control group. Conclusion:Vitamin D may reduce the vascular complications and tissue injuries induced by diabetes in aorta. This effect has a positive influence on the function of the cardiovascular system.

Aim of the Work: This study was carried out to show the effect of lead acetate on the developing metanephros in rabbit. Material and Methods:A total number of 60 rabbit embryos and newborn rabbits were divided into 2 groups, control (n=30) and experimental (n=30). The pregnant mothers of the experimental group received 15 mg / kg BW lead acetate by intragastric intubation on the 10th day of pregnancy until birth. The control group received sodium acetate on the same regimen. For light microscopic study, the specimens were processed on gestational days 16, 20, and 24 and the age of newborn and stained with haematoxylin and eosin and periodic acid Schiff reagent. In two age groups, 24 days prenatal and newborn (control and treated), morphometric measurements were performed to study the diameter and the number of glomeruli and tubules. Also, the glomerular space was measured. Kidney specimens from fetuses on gestational day 26 and from newborns were processed for transmission and scanning electron microscopic study. Results:The control animals showed that the metanephros appeared as a circumscribed mass behind the caudal part of the mesonephros at the age of 16 days prenatal. At the age of 20 days prenatal beneath the renal capsule, the metanephros showed a developed nephrogenic zone containing different stages of nephron development. In the succeeding ages, this nephrogenic zone increased in thickness until birth where it was still persistent. In the experimental group, there were dispersion and disorganization of the metanephric cells and the nephrogenic zone at early ages. In the succeeding ages, cavitations, dilated vascular spaces, increased interstitial tissues with degenerative changes in the glomeruli and tubules of the kidney were observed. At 26-day-old embryo, semithin sections showed degeneration of the cells of the proximal convoluted tubules with irregular vacuolations, clumped intracytoplasmic dark granules and severely damaged brush borders. Cells of the distal convoluted tubules were degenerated. The glomeruli showed dilated congested capillaries with some glomeruli showing dilated glomerular space. These manifestations became more apparent in leaded newborns. Ultrathin sections showed injured epithelial cells of the proximal convoluted tubules with damaged microvilli, vacuolated cytoplasm, swollen mitochondria and degeneration of their cristae. Inclusion bodies and metal deposits were observed in the cytoplasm. In leaded newborns, massive degeneration was observed. Scanning electron microscopy showed marked degeneration of the glomeruli and tubules as compared with the control. Morphometric measurements showed significant reduction in the glomerular diameter, the tubular diameter and the number of glomeruli and tubules per mm with significantly widened glomerular space in lead-treated animals in comparison with the control animals.