Browsing by Author "Kimaro, Wahabu Hamisi"

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An immunohistochemical and ultrastructural study of the ovary of the immature ostrich (struthio camelus)
(University of Pretoria, 2005) Kimaro, Wahabu Hamisi
The aim of this study was to investigate the components of the ovary in the sexually immature ostrich by using immunohistochemistry, light microscopy and electron microscopy. The light and electron microscopic studies carried out, revealed that the oocyte in the sexually immature ostrich is surrounded by seven layers which included the zona radiata, lamina perivitellina, stratum granulosum, basal lamina, thecal layers (theca interna and theca externa), connective tissue layer and superficial epithelium (see details in Chapter Two and Three). Several morphological and immunohistochemical changes occurred as the follicles developed and regressed, suggesting that ovarian follicles in the sexually immature ostrich undergo a cycle of growth and degeneration as reported in other avian species. In the present study, thecal gland cells in the ovary of the sexually immature ostrich were common. In addition, interstitial gland cells were a notable feature in atretic follicles as described in the ovary of the crow, common myna and dove (Guraya and Chalana, 1976). Further investigations on the interstitial gland cells will provide an insight into the process of steroidogenesis in the sexually immature ostrich. As discussed in Chapter five, various cells in the ovary showed immunoreactivity to oestrogen, progesterone and androgen receptors. These observations indicated that the ovarian tissue in the sexually immature ostrich is a potential target for gonadal hormones. Thus, it can be assumed that steroid hormones regulate ovarian functions in the ostrich. The use of immunohistochemical procedures proved to be an excellent method to investigate the distribution of nerves in the ovary. The results of this study have shown that the ovary in the sexually immature ostrich is well- innervated. However, further studies are required to differentiate between cholinergic and adrenergic nerve fibres.
The emerging roles of the calcineurin-nuclear factor of activated t-lymphocytes pathway in nervous system functions and diseases
(Hindawi, 2016) Kipanyula, Maulilio John; Kimaro, Wahabu Hamisi; Seke Etet, Paul F
The ongoing epidemics of metabolic diseases and increase in the older population have increased the incidences of neurodegen- erative diseases. Evidence from murine and cell line models has implicated calcineurin-nuclear factor of activated T-lymphocytes (NFAT) signaling pathway, a Ca 2+ /calmodulin-dependent major proinflammatory pathway, in the pathogenesis of these diseases. Neurotoxins such as amyloid-β, tau protein, and α-synuclein trigger abnormal calcineurin/NFAT signaling activities. Additionally increased activities of endogenous regulators of calcineurin like plasma membrane Ca 2+ -ATPase (PMCA) and regulator of calcineurin 1 (RCAN1) also cause neuronal and glial loss and related functional alterations, in neurodegenerative diseases, psychotic disorders, epilepsy, and traumatic brain and spinal cord injuries. Treatment with calcineurin/NFAT inhibitors induces some degree of neuroprotection and decreased reactive gliosis in the central and peripheral nervous system. In this paper, we summarize and discuss the current understanding of the roles of calcineurin/NFAT signaling in physiology and pathologies of the adult and developing nervous system, with an emphasis on recent reports and cutting-edge findings. Calcineurin/NFAT signaling is known for its critical roles in the developing and adult nervous system. Its role in physiological and pathological processes is still controversial. However, available data suggest that its beneficial and detrimental effects are context-dependent. In view of recent reports calcineurin/NFAT signaling is likely to serve as a potential therapeutic target for neurodegenerative diseases and conditions. This review further highlights the need to characterize better all factors determining the outcome of calcineurin/NFAT signaling in diseases and the downstream targets mediating the beneficial and detrimental effects.
Morphological study of the effect of the cytoskeletal disruptingagent carbendazim on the oviduct of the japanese quail (coturnix coturnix japonica)
(University of Pretoria, 2012) Kimaro, Wahabu Hamisi
Carbendazim (methyl-2-benzimidazole carbamate), a derivative of N-substituted esters of carbamic acid, is widely used as a fungicide on field crops. Carbendazim is of major concern to human and animal health due to the presence of its metabolites and residues in the environment. Several studies have shown the effect of carbendazim on the reproductive systems of male mammals and birds. Relatively little is known of the effect of carbendazim on the female reproductive tract. Therefore, this study was undertaken to establish the effect of carbendazim on the morphological, histochemical and immunohistochemical features of selected regions of the oviduct in the Japanese quail. The functional implication for each region was also considered.