Behavior of human neural progenitor cells transplanted to rat brain

Human neural stem/progenitor cells provide a useful tool for studies of neural development and differentiation, as well as a potential means for neuroreplacement therapeutic needs in the human CNS. Stem cells isolated from developing human central nervous system of 8-12-week fetuses were transplanted to the forebrain and cerebellum of young and adult rats after 14 days of in vitro expansion. Cells were labeled by bisbenzimide prior to transplantation without immunosuppression. Recipient brains were examined 10 and 20 days after transplantation. Labeled stem cells were found in the neocortex, lateral ventricle and caudate nucleus in the forebrain, and in the molecular layer, Purkinje cell layer, and granular layer of the cerebellum. Mitotically dividing stem cells were observed in graft core, confirming their proliferative potential in new microenvironment. Engrafted cells migrate through the parenchyme of striatum, along the ventricular ependymal layer and callosal fibers, some of them reaching the opposite hemisphere. Some cells migrating along the capillaries express glial acid fibrillary protein, demonstrating their differentiation into astrocytes. Grafted cells expressing calbindin were found in the Purkinje cell layer, suggesting their differentiation into the Purkinje cells. At the same time, some grafted cells were undifferentiated and expressed vimentin. Our results demonstrate that cultured human neural stem/progenitor cells migrate and differentiate into both neurons and astrocytes after transplantation to the rat forebrain or cerebellum of young and adult rats.     

Distant cortical locations of the upper and lower quadrants of the visual field represented by neurons with elongated and radially oriented receptive fields

In our previous study of the cytoarchitectonic field 7 of cat cortex we had described neurons with extremely elongated receptive fields (RFs). The long axes of these RFs were oriented radially, towards the centre of the retina. These neurons represented only the lower contralateral part of visual field. They were surrounded from all sides by neurons with clearly different RF properties. We proposed that neurons with a similar radial organization and with RFs in the upper visual field also exist in the cortex but are localized in the area that was distant from the representation of the corresponding lower visual field. We expected to find these neurons in front of the representation of the upper visual field in areas V1, V2 and V3 (fields 17, 18 and 19), behind the central representation in area 21a. This cortical region was studied in five behaving cats. In all animals, neurons with radial RFs in the upper visual field were found in the expected location. As in the lower visual field, their RFs always spared the central visual field. Other RF properties of these neurons were also very similar to those found previously in the lower visual field. It became obvious that neurons with radial RFs are included into the fourth extrastriate crescent with complete contralateral representation. However, in the fourth crescent, RF properties in the central visual field differed significantly from those on the periphery. As a result, neurons with similar radial RFs in the upper and lower visual fields were located in the distant cortical regions, and were separated by the representation of the central visual field presented by the non-radial neurons of the cytoarchitectonic area 21a.     

Transplantation of Cultured Human Neural Progenitor Cells into Rat Brain: Migration and Differentiation

We studied the fate in vitro cultured human stem/progenitor cells after transplantation into rat brain. The cells from human fetuses at 8-12 weeks' gestation were cultured in vitro for 14 days and transplanted into the brain of 10-day-old and adult rats. Microscopic examination showed that human stem/progenitor cells migrated into various regions of rat brain. Immunohistochemical assay demonstrated that some cells differentiated into astrocytes and neurons, while others retained the embryonic phenotype.     

Headache in lacunar stroke

The presence of headache within a 72-h interval of stroke onset was investigated in a cohort of 145 lacunar infarcts. Fourteen (10%) experienced diffuse or bilateral headache. Hypertension was less frequent (43 vs 76%; 95% CI: 6 to 60%) and of shorter duration (2.4 vs 7.8 years; t = 2.29; p = 0.02) among patients with headache. Leukoaraiosis was less frequent (40% vs 71%; 95% CI: −57 to −7%) and severe (7 vs 24%; 95% CI: −33 to −2%) in patients with headache. Age, sex, stroke risk factors, type of lacunar stroke, mode of onset, stroke severity, ultrasound and other CT findings were similar in patients with and without headache. No differences in the sixth month neurological or functional outcome were detected between lacunar patients with and without headache. Headache in lacunar stroke cannot be predicted by the clinical characteristics of the stroke and is not due to coexisting cardiembolism, intra or extracranial disease. Hypertensive small-vessel disease is less common and severe in lacunar strokes with associated headache.     

Cyclosporin nephrotoxicity in heart and lung transplant patients

Twenty-two patients with heart, lung or heart and lung transplants maintained on cyclosporin for periods ranging from 3 months to 10 years developed renal insufficiency which was investigated by renal biopsy. The histopathological changes were: (i) severe vascular and glomerular damage due to thrombotic microangiopathy (TM); (ii) a form of focal segmental glomerulosclerosis (FSGS); (iii) glomerular ischaemia. Rather than being separate entities, these changes appeared to represent a spectrum of pathology, some biopsies showing all three forms of glomerular injury. In all cases the glomerular changes were accompanied by arteriolar and arterial pathology, and we identified novel ultrastructural changes in the arteriolar endothelial basal lamina. Tubular atrophy was a consistent feature, the severity of which reflected the severity of the glomerular sclerosis, and which appeared to be a consequence of glomerular loss. Our findings are consistent with the nephrotoxic effects of cyclosporin being mediated chiefly via damage to preglomerular vessels and glomerular capillary endothelium. From an analysis of the clinical aspects of these cases, the effects of cyclosporin appear to be to some extent idiosyncratic, and therefore not entirely preventable, but strict monitoring of blood cyclosporin levels is essential to minimize the risk of permanent renal damage. Monitoring urinary protein in addition to plasma creatinine may detect the onset of FSGS, as proteinuria precedes creatinine elevation.      

Blood transfusion practices in military medicine

Background: This observational study was conducted in a small, 45 bed border static hospital, located in a field area, where no blood bank facilities were available. The present study was conducted to elucidate the blood transfusion practices of this hospital.