Histopathological patterns and topographical distribution of Kaposi Sarcoma at Muhimbili National Hospital, Tanzania

Background: Kaposi sarcoma (KS) is derived from endothelial cell lineage; it is caused by Human Herpes Virus-8 (HHV-8) facilitated by immune suppression. KS remains one of the commonest sarcoma seen in Tanzania. The paucity of recent data makes monitoring the disease a challenge. This study describes the Histopathological Patterns and Topographical distribution of Kaposi Sarcoma at Muhimbili National Hospital, a tertiary care hospital in Tanzania. Methods: A hospital-based retrospective cross-sectional study was done to review biopsies sent to the Central Pathology Laboratory (CPL), Muhimbili National Hospital from 2010 to 2014. Results: A total of 818 cases representing 1.8 % of all malignancies during the study period were enrolled in the study. The age of patients at diagnosis ranged from 6 months to 94 years old, with the median age being 37 years. Male to female ratiowas 1.4:1.0. Females were younger than males (p < 0.001). The majority of the lesions were in the lower limbs, 352 (64.1%). Nodular KS accounted for 74.5% of all cases. Conclusion: Kaposi’s sarcoma remains a common malignancy. The patients present late at diagnosis. Early diagnosis and improved treatment protocols remain to be key steps towards reducing the burden of KS. Keywords: Kaposi's Sarcoma; Histopathological Patterns; Topographical distribution.

Anatomical and Topographical Variations in the Distribution of Brain Metastases Based on Primary Cancer Origin and Molecular Subtypes: A Systematic Review

Background While it has been suspected that different primary cancers have varying predilections for metastasis in certain brain regions, recent advances in neuro-imaging and spatial modeling analytics have facilitated further exploration into this field. Methods A systematic electronic database search for studies analyzing the distribution of brain metastases (BM) from any primary systematic cancer published January 1990-July 2020 was conducted using PRISMA guidelines. Results Two authors independently reviewed 1,957 abstracts, 46 of which underwent full-text analysis. A third author arbitrated both lists; 13 studies met inclusion/exclusion criteria. All were retrospective single- or multi-institution database reviews analyzing over 8,227 BMs from 2,599 patients with breast (8 studies), lung (7 studies), melanoma (5 studies), gastrointestinal (4 studies), renal (3 studies), and prostate (1 study) cancers. Breast, lung, and colorectal tended to metastasize to more posterior/caudal topographic and vascular neuroanatomical regions, particularly the cerebellum, with notable differences based on subtype and receptor expression. HER-2 positive breast cancers were less likely to arise in the frontal lobes or subcortical region, while ER-positive and PR-positive breast metastases were less likely to arise in the occipital lobe or cerebellum. BM from lung adenocarcinoma tended to arise in the frontal lobes, and squamous cell carcinoma in the cerebellum. Melanoma metastasized more to the frontal and temporal lobes. Conclusion The observed topographical distribution of BM likely develops based on primary cancer type, molecular subtype, and genetic profile. Further studies analyzing this association and relationships to vascular distribution are merited to potentially improve patient treatment and outcomes.

Quantification and Topographical Distribution of Terminal and Linked Fucose Residues in Human Spermatozoa by Using Field Emission Scanning Electron Microscopy (FE-SEM)

The modification of sperm glycocalyx is an essential process during sperm capacitation. The presence and redistribution of terminal and linked fucose have been described during in vitro capacitation in humans. However, the influence of the capacitation time on the quantification and localization of terminal and linked fucose is still unknown. In this study, the quantitative and qualitative changes in fucosyl residues during different in vitro capacitation times (1 and 4 h), are simultaneously characterized by using Aleuria aurantia (AAA) lectin–gold labelling and high-resolution field emission scanning electron microscopy (FE-SEM) in human sperm. A significant decrease was found in the number of terminal fucose registered in the whole sperm head during the in vitro capacitation. Nevertheless, the quantification of fucose residues after 1 h of in vitro capacitation was very similar to those found after 4 h. Therefore, the changes observed in terminal and linked fucose during capacitation were not time-dependent. Furthermore, the comprehensive analysis of the topographic distribution showed the preferential fucosyl location in the acrosomal region and the presence of distinct clusters distributed over the head in all the studied conditions. Overall, these findings corroborate the validity of FE-SEM combined with gold labelling to register changes in surface molecules during in vitro sperm capacitation.

Morphology and Distribution of Cutaneous Sensory Organs on the Digits of Anolis carolinensis and A. sagrei (Squamata: Dactyloidae) in Relation to the Adhesive Toepads and Their Deployment

Cutaneous sensory organs are characteristic of many squamate lineages. Such organs may occur on the surface of scales as button-like, circular protuberances set off from their surroundings by a noticeable boundary, often taking the form of a moat or furrow. They may be relatively unadorned, clad with the surface micro-ornamentation of the scales on which they are carried, or they may carry one or more bristles of varying length and surface ornamentation. Such bristles may extend away from the body of the organ to interface with the surrounding environment or to contact adjacent scales. Cutaneous sensory organs have been physiologically demonstrated to have a mechanoreceptive function but have also been posited to potentially be involved with additional sensory modalities. Their distribution and structure across the body surface has been shown to be unequal, with some regions being much more extensively endowed than others, indicative of regional differential sensitivity. The digits of Anolis (Iguania: Dactyloidae) carry adhesive toepads that are convergent with those of geckos (Gekkota). Geckos exhibit a high density of cutaneous sensory organs on their toepads and their form and distribution has been associated with the operation and control of the toepads during locomotion. Investigation of the form and topographical distribution of cutaneous sensory organs on the toepads of Anolis shows them to be convergent in these attributes with those of geckos and quite distinct from those of the ancestrally padless Iguana (Iguania: Iguanidae). Their location at scale margins and the direction of their bristles towards adjacent scales indicates that the cutaneous sensory organs play an important role in proprioception during toepad deployment in Anolis.

Topographic connectivity and cellular profiling reveal detailed input pathways and functionally distinct cell types in the subthalamic nucleus

SummaryThe subthalamic nucleus (STN) controls psychomotor activity and is an efficient therapeutic deep brain stimulation target in Parkinson’s disease patients. Despite evidence indicating position-dependent therapeutic effects and distinct functions within the STN, input circuit and cellular profile in the STN remain largely unclear. Using advanced neuroanatomical techniques, we constructed a comprehensive connectivity map of the indirect and hyperdirect pathways in both the mouse and human STN. Our detailed circuit- and cellular-level connectivity revealed a topographically graded organization with three convergent types of indirect and hyperdirect-pathways. Furthermore, we identified two functional types of glutamatergic STN neurons (parvalbumin, PV +/- neurons) segregated with a topographical distribution. Glutamatergic PV+ STN neurons contribute to burst firing. We confirmed synaptic connectivity from indirect and hyperdirect pathways to both PV+ and PV-. These data suggest a complex interplay of information integration within the basal ganglia underlying coordinated movement control and therapeutic effects.

Regional Variation of Gap Junctional Connections in the Mammalian Inner Retina

The retinas of many species show regional specialisations that are evident in the differences in the processing of visual input from different parts of the visual field. Regional specialisation is thought to reflect an adaptation to the natural visual environment, optical constraints, and lifestyle of the species. Yet, little is known about regional differences in synaptic circuitry. Here, we were interested in the topographical distribution of connexin-36 (Cx36), the major constituent of electrical synapses in the retina. We compared the retinas of mice, rats, and cats to include species with different patterns of regional specialisations in the analysis. First, we used the density of Prox1-immunoreactive amacrine cells as a marker of any regional specialisation, with higher cell density signifying more central regions. Double-labelling experiments showed that Prox1 is expressed in AII amacrine cells in all three species. Interestingly, large Cx36 plaques were attached to about 8–10% of Prox1-positive amacrine cell somata, suggesting the strong electrical coupling of pairs or small clusters of cell bodies. When analysing the regional changes in the volumetric density of Cx36-immunoreactive plaques, we found a tight correlation with the density of Prox1-expressing amacrine cells in the ON, but not in the OFF sublamina in all three species. The results suggest that the relative contribution of electrical synapses to the ON- and OFF-pathways of the retina changes with retinal location, which may contribute to functional ON/OFF asymmetries across the visual field.

Acute Onset Flaccid Paralysis as Presentation of Combined Central and Peripheral Demyelination in a Child: A Case Report

Introduction: Inflammatory demyelinating disease like combined central and peripheral demyelination (CCPD) could have varied clinical presentation depending upon the topographical distribution of neural involvement. Case presentation: A seven-year-old child had presented with fever followed by acute onset flaccid paralysis and urinary retention. Weakness in the lower limbs as reported was ascending and symmetric in nature, while no history of trauma, band-like sensation or altered sensorium were documented. Superficial and deep tendon reflexes of both the lower limbs were absent. Routine blood investigations had revealed neutrophilic leucocytosis only. Serum IgM antibody for scrub typhus was found positive. CSF study didn’t show cyto-protein dissociation. NCV had demonstrated absence of F wave and H reflex in the peripheral nerves of lower limbs. Anti-ganglioside antibody profiles were negative. Subsequent investigations including MRI brain and spinal cord had revealed acute onset CCPD. Conclusion: Acute onset combined central and peripheral demyelination in a child had presented as acute flaccid paralysis of the lower limbs and the condition was temporally association with scrub typhus.