Astrocyte morphology, heterogeneity, and density in the developing African giant rat (Cricetomys gambianus)

Astrocyte morphologies and heterogeneity were described in male African giant rats (AGR; Cricetomys gambianus, Waterhouse) across three age groups (five neonates, five juveniles, and five adults) using Silver impregnation method and immunohistochemistry against glial fibrillary acidic protein. Immunopositive cell signaling, cell size and population were least in neonates, followed by adults and juveniles, respectively. In neonates, astrocyte processes were mostly detected within the glia limitans of the mid and hind brain; their cell bodies measuring 32 ± 4.8 μm in diameter against 91 ± 5.4 μm and 75 ± 1.9 μm in juveniles and adults, respectively. Astrocyte heterogeneity in juvenile and adult groups revealed eight subtypes to include fibrous astrocytes chiefly in the corpus callosum and brain stem, protoplasmic astrocytes in the cortex and dentate gyrus (DG); radial glia were found along the olfactory bulb (OB) and subventricular zone (SVZ); velate astrocytes were mainly found in the cerebellum and hippocampus; marginal astrocytes close to the pia mater; Bergmann glia in the molecular layer of the cerebellum; perivascular and periventricular astrocytes in the cortex and third ventricle, respectively. Cell counts from twelve anatomical regions of the brain were significantly higher in juveniles than in adults (p ≤ 0.01) using unpaired student t-test in the cerebral cortex, pia, corpus callosum, rostral migratory stream, DG, and cerebellum. Highest astrocyte count was found in the DG, while the least count was in the brain stem and sub cortex. Astrocytes along the periventricular layer of the OB are believed to be part of the radial glia system that transport newly formed cells towards the hippocampus and play roles in neurogenesis migration and homeostasis in the AGR. Therefore, astrocyte heterogeneity was examined across age groups in the AGR to determine whether age influences astrocytes population in different regions of the AGR brain and discuss possible functional roles

Ultrastructural studies of acrosomal formation in the testis of male greater cane rat (Thryonomys swinderianus)

Purpose: In furthering the understanding of the process of spermatogenesis in the greater cane rat, this study describes the ultrastructural spermiogenic transformation and acrosomal formation in the testes of this hystricomorphic rodent that is currently undergoing domestication in parts of West Africa. Materials and Methods: Testicular samples were obtained from ten sexually mature cane rats that were perfused-fixed using Karnovsky\u27s fixative (phosphate buffered 2% paraformaldehyde – 2.5% glutaraldehyde fixative at pH 7.4). The samples were processed for ultrastructural analysis and examined under the transmission electron microscope. Results: The testes of the cane rat showed uniqueness in its cellular associations and the ultrastructure of the spermatogenic cells especially in the formation of the acrosome. The spermatid differentiation and acrosomal formation occurred in 12 steps with the first three steps being the Golgi phase and the next three steps making up the cap phase. While the three steps that follow constitute the acrosomal phase, the last 3 steps make up the maturation phase. At the cap and acrosomal phases, the entire acrosomal system comprising the vesicle and granule covers the head of the spermatids with no clear indentation of the nuclear surface by the formed acrosome. Furthermore, elongated spermatids at the maturation phase contained abundance of nuclear vacuoles. Conclusion: This work has not only provided information that will further the understanding of spermatogenesis but also aid the understanding of acrosomal reaction in the reproduction of the greater cane rat

Anatomical variations and morphometric properties of the circulus arteriosus cerebri in a cadaveric Malawian population

Background: Knowledge of the anatomy of the circulus arteriosus cerebri (CAC) is important in understanding its role as an arterial anastomotic structure involved in collateral perfusion and equalization of pressure, and may explain observed variations in neurovascular disease prevalences across populations. This study was aimed at understanding the anatomical configuration and morphometric properties of the CAC in Malawian population. Materials and methods: Brains were collected from 24 recently-deceased black Malawian human cadavers during medico-legal autopsies. Photographs of the CACs were taken using a camera placed at a 30 cm height from the base of the brain. Whole-circle properties and segmental vessel parameters were analyzed using the OSIRIS computer program, paying attention to completeness, typicality, symmetry, and segmental vessel diameters and lengths. Results: 69.57 % of the CACs exhibited the complete-circle configuration. Of these, 37.5 % were typical, representing an overall typicality prevalence of 26.09 %. Vessel asymmetry was observed in 30.43 % of cases. There were 7 cases of vessel aplasia and 12 cases of vessel hypoplasia. The posterior communicating artery (PcoA) was the most variable (with 12 variations), widest (7.67 mm) and longest (27.7 mm) vessel while the anterior communicating artery (AcoA) was the shortest (0.78mm). Both the AcoA and the PcoA were the narrowest vessels (0.67 mm) in this study. CAC variations in Malawian populations appeared to be similar to those observed in diverse populations. Conclusions: Anatomical variations of the circulus arteriosus cerebri exist in Malawian population and should be taken into consideration in clinical practice

Connective tissue, glial and neuronal expressions in testis of the African giant rat (Cricetomys gambianus)

Introduction: This study was carried out to investigate the expression of connective tissue (Collagens I and III), glia and neuronal markers in the testis of the African giant rat using histology and immunohistochemistry techniques. Materials and Methods: Eight (8) apparently healthy wild male African giant rats were used for this experiment, divided into 2 groups (juvenile and adult) of 4 animals each. The testes were harvested following intracardial perfusion of the rats and histology was performed using Haematoxylin-Eosin stain and Mallory-Heideinhain rapid one- step staining for connective tissue. Immunohistochemical identification was achieved using the following antibodies: anti-collagen type I, anti-collagen type III, anti-glial fibrillary acidic protein and anti-p75 nerve growth factor for the expression of collagen type I, collagen type III, astrocyte-like cell and neuronal cells respectively. Photomicrography was achieved using Axioskop® microscope and quantitative data were analyzed using student t-test. Results: The cyto-architecture of the testis was typical in the African giant rat. The connective tissue expressed in the juvenile and adult group, signaling of glial-like cells were seen in the perivascular region across the experimental groups. Immuno-localization of neuronal cells were seen in the interstitial spaces across all the groups, but with more expressions in the juvenile. Conclusion: This work has provided a clear description of the expression of connective tissue, neuronal and glial cells in the testis of the African giant rat and their possible relationships across juvenile and adult groups

Regular Khat (Catha edulis) chewing is associated with elevated diastolic blood pressure among adults in Butajira, Ethiopia: A comparative study

<p>Abstract</p> <p>Background</p> <p>Fresh leaves and buds of the Khat plant (<it>Catha edulis</it>) contain Cathinone, an amphetamine like alkaloid responsible for its pharmacological action. Chewing of Khat has been associated with a transient rise in blood pressure and heart rate in experimental studies. Few studies examined the effect of regular or frequent Khat chewing on blood pressure at the population level. This study was conducted to examine the association of regular Khat chewing with blood pressure among adults.</p> <p>Methods</p> <p>We compared systolic and diastolic blood pressure of adults 35-65 years of age who reported regular chewing of Khat during the preceding five years to those who never chewed Khat during the same period. Study participants were recruited from purposively selected urban and rural villages of Butajira District in Ethiopia. The comparative groups, chewers (334) and non-chewers (330), were identified from among the general population through a house-to-house visit using a screening questionnaire. They were frequency-matched for sex and age within a five-year range. Data were collected through structured interviews and physical measurements including blood pressure, weight and height.</p> <p>Results</p> <p>The prevalence of hypertension was significantly higher among Khat chewers (13.4%) than non-chewers (10.7%), odds ratio (OR) = 1.66 (95% confidence interval (CI) 1.05, 3.13). A considerably high proportion of chewers (29.9%) than non-chewers (20.6%) had sub-optimal diastolic blood pressure (> 80 mmHg). The mean (sd) diastolic blood pressure was significantly higher among Khat chewers [75.0 (11.6)] than non-chewers [72.9 (11.7)], P < 0.05. Similarly, Khat chewers had significantly higher mean (sd) heart rate [76.3 (11.5)] than non-chewers [73.9 (12.6)], P < 0.05. There was no significant difference in mean systolic blood pressure between the two groups.</p> <p>Conclusion</p> <p>Regular chewing of Khat is associated with elevated mean diastolic blood pressure, which is consistent with the peripheral vasoconstrictor effect of Cathinone. Regular Khat chewing may have sustained effects on the cardiovascular system that can contribute to elevated blood pressure at the population level.</p

What is next in African neuroscience?

Working in Africa provides neuroscientists with opportunities that are not available in other continents. Populations in this region exhibit the greatest genetic diversity; they live in ecosystems with diverse flora and fauna; and they face unique stresses to brain health, including child brain health and development, due to high levels of traumatic brain injury and diseases endemic to the region. However, the neuroscience community in Africa has yet to reach its full potential. In this article we report the outcomes from a series of meetings at which the African neuroscience community came together to identify barriers and opportunities, and to discuss ways forward. This exercise resulted in the identification of six domains of distinction in African neuroscience: the diverse DNA of African populations; diverse flora, fauna and ecosystems for comparative research; child brain health and development; the impact of climate change on mental and neurological health; access to clinical populations with important conditions less prevalent in the global North; and resourcefulness in the reuse and adaption of existing technologies and resources to answer new questions. The article also outlines plans to advance the field of neuroscience in Africa in order to unlock the potential of African neuroscientists to address regional and global mental health and neurological problems

The coagulating gland in the male greater cane rat (Thryonomys swinderianus): morphological and immunohistochemical features

This study reveals the structure, ultrastructure and immunoexpression of oestrogen alpha and beta receptors (ERα and ERβ) in the coagulating glands of the greater cane rat. Gland samples from 15 adult male cane rats were processed for histological and ultrastructural studies while immunohistochemistry was also carried out. Coagulating gland in the cane rat is a paired, triangularly shaped, transparent gland weighing about 1 ± 0.48 g. Histologically, each secretory acinus is composed of folded mucosa surrounded by fibromuscular stroma. The simple columnar epithelium consists of principal cells at different stages of secretion evidenced by their apical blebs of various heights and occasional basal cells. Fine structure of the principal cells revealed the presence of apical blebs that contained secretory granules of varying electron-density, secretory vesicles and vacuoles on both their luminal surfaces and the lumen. While supranuclear cytoplasm contained Golgi apparatus with different cisternal arrangements, the infranuclear part is covered with dilated rough endoplasmic reticulum cisternae. Nuclei, apical bleb and stroma of secretory epithelium all showed positive immunostaining for ERα and ERβ. These findings revealed the prominence of apocrine secretion with no structural evidence of merocrine secretion and the uncommon ERα and ERβ distribution pattern in the coagulating gland of the cane rat

Hypertrophic cardiomyopathy: Case report

A case report of a 19 year old young adult male who died suddenly without any apparent clinical cause is presented. Autopsy examination revealed hypertrophied interventricular septum and left ventricle suggestive of a hypertrophic cardiomyopathy (HCM). About 50% of hypertrophic cardiomyopathies are inherited as autosomal dominant disorder, sometimes associated with neuroectodermal syndromes, such as neurofibromatosis and pheochromocytoma. HCM is one of the common causes of severe arrhythmias and sudden death

Distribution of median nerve to muscles of the anterior compartment of the arm.

Distribution of the median nerve in the arm is not normally subjected to variation. This report represents a case of complete absence of the musculocutaneous nerve from the lateral cord of the brachial plexus. The innervation of the muscles of the anterior (flexor) compartment of the arm was by direct branches from the median nerve. This variation was present in both the right and left limbs