Topographic and Structural Anatomy of the Suspensory Ligament of the Penis: Implications for Phalloplasty.

BACKGROUND: The suspensory ligamentous system of the penis supports the penis when erect and plays a key role during coitus. These ligaments, which are prone to injury during coitus, are clinically important in penile reconstruction procedures. OBJECTIVES: The current study investigated the macro- and microanatomy of the suspensory ligamentous system of the penis to determine the origin, course, insertion, dimensions, and tissue composition of these ligaments, knowledge of which is vital for successful penile reconstruction procedures. METHODS: The study utilized a total of 49 cadavers. Gross anatomy dissection, MRI, and histological staining were performed to elucidate the topography, dimensions, and tissue composition of the suspensory ligaments of the penis. RESULTS: Three ligaments were observed to form the suspensory ligamentous system of the penis. The most superficial is the fundiform ligament, which consists of superficial bundles and deep median bundles, with the former arising from the Scarpa's fascia and the latter arising from the linea alba of the anterior abdominal wall; both inserted into the superficial fascia of the penis. The suspensory ligament of the penis arose from the pubic symphysis and inserted into the deep fascia (Buck's fascia) of the penis. The arcuate ligament arose from the body of the pubis and pubic symphysis and inserted into the Buck's fascia. The ligaments were determined to consist of adipose tissue, collagen fibers, elastic fibers and reticular fibers, in varying proportions. CONCLUSIONS: The suspensory ligaments of the penis exhibit a fan-like structure on the penis that allows the forward movement of the penis as a result of engorgement of the erectile bodies while simultaneously offering support.

Neurogenesis and Viral Infection.

Neural stem cells (NSCs) are multipotent stem cells that reside in the fetal and adult mammalian brain, which can self-renew and differentiate into neurons and supporting cells. Intrinsic and extrinsic cues, from cells in the local niche and from distant sites, stringently orchestrates the self-renewal and differentiation competence of NSCs. Ample evidence supports the important role of NSCs in neuroplasticity, aging, disease, and repair of the nervous system. Indeed, activation of NSCs or their transplantation into injured areas of the central nervous system can lead to regeneration in animal models. Viral invasion of NSCs can negatively affect neurogenesis and synaptogenesis, with consequent cell death, impairment of cell cycle progression, early differentiation, which cause neural progenitors depletion in the cortical layer of the brain. Herein, we will review the current understanding of Zika virus (ZIKV) infection of the fetal brain and the NSCs, which are the preferential population targeted by ZIKV. Furthermore, the potential neurotropic properties of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may cause direct neurological damage, will be discussed.

Distribution of variations in anatomy of the circle of Willis: results of a cadaveric study of the Malawian population and review of literature.

INTRODUCTION: the circle of Willis is an anatomical structure of clinical importance particularly in the evaluation of neurovascular diseases. Individuals show considerable variations in the anatomical configuration of the circle of Willis. A cross-sectional study was conducted to determine the distribution of morphological variations of the circle of Willis in Malawians and compare with other ethnic groups. METHODS: brains were collected from twenty-four recently deceased black Malawians during autopsy at Queen Elizabeth Central Hospital, a referral teaching hospital in Blantyre, Malawi and fixed in 10% buffered formalin. Digital images of the interpeduncular region (exposing the circle of Willis) were taken with an 18.4 megapixels camera from the base of the brain. Whole-circle and segmental parameters of the circle of Willis were assessed using the Osiris computer programme and classified based on a 22-type classification scheme. RESULTS: the following morphological variations were observed: hypoplasia, aplasia, asymmetry and accessory vessels. Typical circle of Willis was seen in 26% of the cases. Only six of the original twenty-two types were observed. Consistent with most previous studies, types 1, 3, 4, 6, 8 and 9 were common while types 10-22 were rare. Three variants not previously described in the original scheme (unilateral PcoA aplasia, AcoA duplication, and PcoA aplasia with contralateral PcoA hypoplasia) were observed in this study. CONCLUSION: anatomical variations of the circle of Willis in Malawians seem to be distributed in similar frequencies and patterns as in other more-diverse populations. Circle of Willis variants with potential predilection for atherogenesis and aneurysm formation exist in the Malawian population. These should be considered in clinical practice.

Coadministration of ARV (Atripla) and Topiramate disrupts quail cardiac neural crest cell migration.

INTRODUCTION: Congenital anomalies such as ventricular septal defects and truncus communis have been reported with the prenatal use of antiretroviral therapy. The mechanism of antiretroviral therapy teratogenicity is unclear and is therefore the focus of this study. Some human immunodeficiency virus patients on antiretrovirals are placed on antiepileptic drugs which are also teratogenic. The interactive effects arising from this therapeutic combination may affect their teratogenic propensity through their effects on neural crest cell migration. METHODS: Appropriately cultured neural crest cells from dissected neural tubes of 32-hr old quail embryos exposed to culture media containing peak plasma levels of Atripla, Topiramate and the combination of both were studied. Distance of migration of neural crest cells was measured using the migration assay and the cells were stained with rhodamine phalloidin to evaluate the cell actin. Also quail neural crest cells were brought into suspension and microinjected into chick hosts to determine the migration of the cells to the interventricular septum. RESULTS: Migration of cultured neural crest cells was extensive in the control cultures, but inhibited in the treated groups. The experimental cultures showed a disarray of actin cytoskeleton contrary to normal distribution of actin filaments in controls. Significantly, few quail neural crest cells migrated to the interventricular septum of chick host embryos compared to the control cultures. The coadministration of topiramate with antiretroviral therapy does not seem to affect the activity of the antiretroviral drug. CONCLUSION: These results indicate that Atripla and Topiramate cause ventricular septal defects by inhibiting the migration of cardiac neural crest cells.

Adult neurogenesis in the African giant rat (Cricetomysgambianus, waterhouse).

African giant rats (AGR) are large nocturnal rodents with well-developed olfactory abilities uniquely linked to cognition. The post natal proliferation of neurons (adult neurogenesis), is thought to play an important role in spatial memory and learning. Eighteen brains of the African giant rats (Cricetomys gambianus, Waterhouse) belonging to three age groups (neonates n = 6, juveniles n = 6 and adults n = 6) were examined by immunohistochemistry, using antibodies for proliferating cells (Ki-67), and immature neurons (Doublecortin, DCX). Mean brain weights were 0.40 ± 0.00 g; 4.48 ± 0.43 g and 5.48 ± 0.56 g for neonate, juvenile and adult brains respectively. Our results show positive cell proliferation in the subventricular (SVZ) zone of the lateral ventricle and in the dentate gyrus (DG) of the hippocampus but at low levels in adults compared to juveniles. Estimate of the mean total proliferative Ki-67 positive cells in the SVZ and DG in the neonates was 21145 ± 8395, and 11800 ± 1230; brains from juvenile AGRs, 45530 ± 13950 and 12480 ± 7860 and from adult brains, (6880 ± 340 and 1130 ± 150) respectively. Juvenile AGR in particular, stained positively in potential sites such as the piriform and somatosensory cortices, striatum and cerebellum. This intensity of the proliferating cells within the dentate gyrus in the juvenile and adult brains could be associated with a role in the cognitive functions of landmine detection and tuberculosis diagnosis after olfactory training of the African giant rat. The juvenile rats are proposed as the most suited for experimental research and olfactory training.

Histology and ultrastructure of transitional changes in skin morphology in the juvenile and adult four-striped mouse (Rhabdomys pumilio).

The four-striped mouse has a grey to brown coloured coat with four characteristic dark stripes interspersed with three lighter stripes running along its back. The histological differences in the skin of the juvenile and adult mouse were investigated by Haematoxylin and Eosin and Masson Trichrome staining, while melanocytes in the skin were studied through melanin-specific Ferro-ferricyanide staining. The ultrastructure of the juvenile skin, hair follicles, and melanocytes was also explored. In both the juvenile and adult four-striped mouse, pigment-containing cells were observed in the dermis and were homogeneously dispersed throughout this layer. Apart from these cells, the histology of the skin of the adult four-striped mouse was similar to normal mammalian skin. In the juvenile four-striped mouse, abundant hair follicles of varying sizes were observed in the dermis and hypodermis, while hair follicles of similar size were only present in the dermis of adult four-striped mouse. Ultrastructural analysis of juvenile hair follicles revealed that the arrangement and differentiation of cellular layers were typical of a mammal. This study therefore provides unique transition pattern in the four-striped mouse skin morphology different from the textbook description of the normal mammalian skin.