Morphological Characterization of the African Giant Rat (Cricetomys gambianus, Waterhouse) Brain Across Age Groups: Gross Features of Cortices

This experiment was designed to investigate the morphological characterization of the brain cortices of African giant rats, AGR (Cricetomys gambianus, Waterhouse) across age groups as related to function. A total of 15 male AGR were used for this study comprising of 5 neonates, 5 juveniles and 5 adults. Brains were described as having typical rodent features; the falx cerebri, the dura modification of interest, was partly inserted between the lobes of the olfactory bulb and extended towards the corpus callosum. Gross parameters extrapolated include cerebral and cerebellar cortical dimensions using a one-way ANOVA (p≤0.05). Most values showed highest significant value bias for juveniles over adults and neonates. The average brain weight was 5.60±0.06g, 4.64±0.17g and 0.62±0.08g; cortex volume: 2.84±0.04cm3, 3.16±0.10cm3 and 0.23±0.02cm3 and antero-posterior dimensions: 11.93±0.26mm, 14.54±0.22mm and 6.00±0.16mm for adult, juvenile and neonates respectively. There was however adult bias in the cerebellum weight (0.83±0.02g, 0.76±0.02g and 0.04±0.02g); vermis length (13.23±0.32mm, 11.27±0.014mm and 0.24±0.02mm) and the antero-posterior length values (8.79±0.19mm, 6.97±0.03mm and 0.29±0.01mm) for adults, juveniles and neonates AGR respectively. Cortical parameters were related as a function of the brain development and plasticity, while age was described to play functional roles in intelligence determination of the AGR. The result of this study will be useful as baseline information for post mortem studies, medical imaging and useful as diagnostic tool for future research work on the AGR brain.Keywords: African giant rats, Brain, Morphology, Cerebrum, Cerebellum, Olfactory bul

Anatomical studies on the spinal cord of the greater cane rat (Thryonomys swinderianus, Temminck) II: histomorphology and spinal tracings

The field of neuroanatomy and the knowledge of spinal cord, in particular, requires an accurate base on which data can be mapped. Lately, researchers have taken into consideration studies on Greater cane rat (GCR) because of its large body size and African origin. This study was designed to elucidate the histomorphologic features of the GCR spinal cord. A total of 10 adult GCR (five males and five females) raised in captivity were used for this study. Twenty-seven spinal segments (Cervical-8, Thoracic-13, Lumbar-5 and Sacral-1) were identified. Each segment was transected, processed histologically into Nissl-stained sections and observed features of the spinal cord were described. The GCR spinal segments possess the typical Hshaped inner gray matter core surrounded by an outer white matter. Variations in the shape of the central canals were observed across the spinal segments. A total of sixty-four features were delineated: twelve observed in the white matter, forty-nine in the gray matter and the remaining three were attached to the spinal cord. Laminar organisations, tracts, nuclei and motor neuron groups of the spinal cord identified were also traced and possible functions adduced in this rodent. No sexual dimorphism was observed in this study. This work has provided valuable and qualitative baseline information for understanding the laminar characteristics relevant to pathophysiologic conditions of the spinal cord. It has also contributed to the knowledge of neuroanatomy of this rodent and will be valuable for spinal cord research especially in this species.Keywords: Spinal cord, Greater cane rat, Histology, Laminar organisation, Spinal tracing

Processing rodent brain tissues: review of basic anatomical techniques for scientists with minimal knowledge of neuroanatomy

An understanding of brain structure, how to harvest rodent brain samples and the various histological procedures to follow is imperative in conducting researches in neuroscience especially for beginners. The general brain aversion bias and complexity of studying the brain, poses a real challenge in identifying and understanding its anatomy either grossly or microscopically. Therefore, this review attempts to provide a basic explanation for researchers with little knowledge of neuroanatomy but are interested in processing brain tissues ranging from opening the skull of the rodents, harvesting freshly perfused or unperfused brain, weighing of the brain and identifying various landmarks on the brainstem, cerebellum, and cerebrum. This review further provides a clue to the various anatomical landmarks in the brain and the functional role each structure identified in such landmarks play. Since most of the brain cytoarchitecture is viewed microscopically, knowing the appropriate staining techniques that clearly show the desired brain cell or region in question is important in determining various neuropathologies as well as in conducting various pilot studies on the brain. This review therefore provides a solid foundation for researchers who are not too familiar with the brain but need to conduct various studies on it.Keywords: brain, histological procedures, anatomical landmarks, staining techniques, cytoarchitecture, fixatio

An anatomical perspective: does the male greater cane rat (Thryonomys swinderianus) have a scrotum?

We evaluated the anatomy of the “scrotal” skin pouch in an attempt to answer the question of whether (or not) there exist true scrotum in the greater cane rat (Thryonomys swinderianus). The “scrotal” skin folds from ten (10) matured male cane rats were morphologically and morphometrically studied with samples routinely processed for histology. Grossly, the pouch has features like fine hair on thin skin and longitudinal raphae typical of scrotum in other species. The histoarchitecture of the “scrotal” skin in the cane rat follows the normal scrotal pattern and the arrangements of the cutaneous strata, hair follicles and glands were similar in animals with perineal staining and those without perineal stain. The cane rat scrotal skin, though different in conformation from the scrotum of other mammalian species, has all the properties of a true scrotum thereby establishing the presence of scrotum in the greater cane rat.Keywords: Scrotum, Greater cane rat, Skin Pouch, Perineal stainin

Use of stool culture as a non invasive method for the diagnosis of Helicobacter pylori from stool of diarrhoeic children in western Nigeria

Background: Helicobacter pylori has been associated with chronic diarrhoea, iron deficiency anaemia, growth retardation, gastric malignancies, peptic ulcer disease, and gastritis among children. Diagnosis of this infection has been invasive using biopsies while stool culture is not common or routinely practiced. This study was designed to detect and isolate H.pylori from stool of diarrhoeic children and highlight possible use of such for routine laboratory diagnosis of H.pylori infections.Material and methods: Two hundred and sixty faecal samples obtained from diarrhoeic children were screened for H. pylori antigen, using H. pylori stool antigen test kit (HpSA) and cultured on modified DENTS medium. Cholestyramine and nitrobluetetrazolium salt were added to the stool and the medium respectively to aid isolation of H. pylori. Correlation of BMI and H. pylori infection of the children was also evaluated.Results: Twenty-six (10%) samples showed growth on culture while 91 (35%) tested positive for H. pylori antigen. Of the 26 children with positive culture, 16 had a low BMI. HpSA has sensitivity and specificity of 11.5% and 62.4%. There was a significant association (χ2 = 12.86, df=2, P-value = 0.004) between age group of participants and use of HpSA kit.Conclusion: Stool culture for recovery of H. pylori is feasible in our environment and diarrhoeic children should be screened for H. pylori using both HpSA and culture. H. pylori is suggested to be screened routinely especially among children having diarrhoea and are underweight. Albeit, other causes should be eliminated before concluding on the reason for the underweight.Keywords:  Helicobacter pylori, stool culture, HpSA, BMI, Cholestyramine, Nitrobluetetrazolium sal

Lattice gas model in random medium and open boundaries: hydrodynamic and relaxation to the steady state

We consider a lattice gas interacting by the exclusion rule in the presence of a random field given by i.i.d. bounded random variables in a bounded domain in contact with particles reservoir at different densities. We show, in dimensions $d \ge 3$, that the rescaled empirical density field almost surely, with respect to the random field, converges to the unique weak solution of a non linear parabolic equation having the diffusion matrix determined by the statistical properties of the external random field and boundary conditions determined by the density of the reservoir. Further we show that the rescaled empirical density field, in the stationary regime, almost surely with respect to the random field, converges to the solution of the associated stationary transport equation

PATHOMORPHOLOGICAL CHANGES AND BACTERIAL PATHOGENS ASSOCIATED WITH SWINE PNEUMONIAS IN SOUTHWEST NIGERIA

Pneumonia is a major economic threat to swine industry worldwide, however, there is still dearth of information on the pathology and associated pathogens in Nigeria, and these were therefore investigated. Lungs from 408 slaughtered pigs were randomly collected from abattoirs in Abeokuta, Ibadan and Lagos. The lung samples were cultured for bacterial pathogens using standard techniques, while formalin-fixed tissues were processed for histopathological examination. Grossly, the most consistent lesion was bronchopneumonia (35.3%). The main histopathological findings were lymphoid hyperplasia of bronchus-associated lymphoid tissue (BALT) (88.2%), suppurative bronchopneumonia (63.6%), suppurative bronchitis and bronchiolitis with concurrent epithelial hyperplasia (57.1%), as well as thickened alveolar septa due to cellular infiltration consisting predominantly of neutrophils (54.1%). Ten different species of bacteria were isolated from the lung samples in which two or more pathogens were isolated from each sample (82.7%). Pasteurella multocida was the most frequently isolated bacterium (54.8%). Among the bacteria isolated, there were significant (P < 0.05) differences in the frequencies of isolation of β-haemolytic Streptococci, P. multocida, Haemophilus species and Escherichia coli between the pneumonic lungs and apparently normal lungs. The results of bacterial culture, gross and histopathological changes recorded in this study are consistent with bacterial pneumonia possibly caused by most of the bacteria identified in the present study.   &nbsp

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Cytoarchitecture of the hippocampal formation in the African giant rat (Cricetomys gambianus, Waterhouse)

Summary: The African Giant Rat, AGR is an indigenous nocturnal rodent noted for its unique olfactory and cognitive abilities. They have been deployed more recently in the detection of landmines and diagnosis of tuberculosis – two scourges that have had a tremendous negative impact on the African landscape. This olfactory-aided cognition has been linked to the hippocampus. While the anatomical infrastructure of the olfactory bulb of the AGR has been elucidated, little is known about the adaptive cytoarchitecture of the AGR hippocampal formation. This study describes the histological features, including subfields and stratifications of the AGR hippocampus using Nissl and Golgi stains. The basic cytoarchitecture of the AGR hippocampus observed in this study, with respect to stratification, subfields and cell types, is similar to those reported in the laboratory rats. Cell types identified in the AGR hippocampus include pyramidal cells, granule cells and mossy cells with mossy fibers and Schaffer collaterals also delineated. Hippocampal proper subfields CA1 to CA4 were identified. CA3 pyramidal neurons formed a well-defined cell layer starting in between the upper and lower ends of the dentate gyrus and had larger, more distinct pyramidal cells and higher cell layer thickness (240.0±6.0 μm) relative to subfields CA1 (87.0±2.0 μm) and CA2 (109.0±4.20 μm) with significant statistical differences at p<0.001. The detailed, delicate arrangement of various cell types and subfields, intricate wiring with synapses and laminar organization of the hippocampal formation noticed in the AGR strongly supports the canonical trisynaptic circuitry of the hippocampus. It will however be necessary to carry out densitometric studies and detailed neurochemical profiling of the AGR hippocampus to fully elucidate the functional leverage of this unique rodent. We, therefore, suggest the suitability of this rodent as a model for olfaction-linked memory studies.Keywords: African giant rat, brain, cornu ammonis, dentate gyrus, hippocampus, histolog

Influence of the areas of specialization of Traditional Medicine Practitioners (TMPS) on the types of formulation prescribed in the management of memory loss

Traditional Medicine Practitioners (TMPs) make use of plants in alleviation of many illnesses including memory loss. Their specialization categories could include traditional healers, herbalists, herb sellers, etc. Most of them learnt the trade as apprentices from their trainers or their parents. This study was designed to investigate if there was an association between the areas of specialization of the TMP and the choice of formulation (mono- or multicomponent herbal) in the management of memory loss. A hundred TMPs consisting of 18 traditional healers and 82 herb sellers in Lagos State were randomly interviewed using a structured questionnaire. Various data on age, sex, areas of specialization of the TMPs, plants used, mode of administration, life forms of plants used and the types of herbal formulation prescribed for memory loss were obtained. The two variables involved (areas of specialization of the TMPs and formulation type) were compared using Chi square statistical tool to measure their association and inferences were drawn from the results. About 88% of all respondents have used multi-component herbal formulations while only 12% have used mono-component herbal formulations. About 82% of all the respondents were herb sellers and 18% of them were traditional healers. About 89% of literate respondents have used multi-component herbal formulations while 11% of them have used mono-component herbal formulations. Similarly, about 89% of herb sellers have used multi-component herbal formulations while about 11% of them have used mono-component herbal formulations. About 83% of traditional healers have used multi-component herbal formulations while about 17% of them have used mono-component herbal formulations. There was no significant association between the types of occupation of the TMPs interviewed and the types of formulation used (p< 0.05). This study shows that the occupations (trades) of TMPs did not influence their choice of type of formulations.Keywords: Mono-component herbal, multi-component herbal, traditional medicine practitioners, occupatio