Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human fetal mesencephalic tissue obtained from elective first-trimester abortions was grafted to 6-hydroxydopamine-denervated striatum of athymic (nude) rats. After 3-6 months, the transplants were evaluated by light and electron microscopy using antibodies against tryosine hydroxylase (TH), human specific Thy-1 (Thy-1), 5-hydroxytryptamine (5-HT), and laminin. In vivo chronoamperometric studies of K+-induced release of electroactive species were done prior to the histochemical evaluations. At the light microscopical level, Thy-1-immunoreactivity was evenly distributed throughout the entire transplants. Thy-1-immunoreactive nerve fibers were observed radiating from the graft into the host striatum. In sections that were double-stained with antibodies against Thy-1 and TH, such nerve fibers contained both markers. Also 5-HT-immunoreactive cells were found in the grafts with processes both in the grafts and radiating into host neuropil. Laminin immunohistochemistry showed an even distribution of capillaries in the graft with less density than in host brain, suggesting immaturity of graft tissue. At the ultrastructural level, TH-immunoreactive axons made symmetric contacts with unlabeled dendritic shafts and dendritic spines within the host brain. A few asymmetric contacts with TH-immunoreactive axons were seen. 5-HT-immunoreactive terminals made both symmetric and asymmetric contacts with unlabeled dendritic shafts and spines. In vivo chronoamperometry using local application of K+ revealed average signals that were lower on the transplanted side than in control striatum. However, close to the grafts significant amounts of the K+-evoked signal amplitudes were as large as 1.3 microM, and the ratio of the reduction to oxidation currents suggested release of a mixture of dopamine and 5-HT. Taken together, this study shows that human fetal mesencephalic tissue pieces survive grafting into nude rats, develop normal vascularization, and express coexistence of TH- and Thy-1-immunoreactivity. Human TH- and 5-HT-immunoreactive nerve fibers form synapses in host striatum and release monoamine neurotransmitters.
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PMID:Human fetal mesencephalic tissue grafted to dopamine-denervated striatum of athymic rats: light- and electron-microscopical histochemistry and in vivo chronoamperometric studies. 256 65

The purpose of the present study is to examine the blood-brain barrier in brain of congenital hydrocephalus HTX rats. We investigated the rat brain from postnatal day 1 to 44 using light and electron microscopy and immunohistochemical methods with monoclonal anti-blood-brain barrier (BBB) antibody. HTX rats developed hydrocephalus at 1-2 days after birth. Most rats succumbed to brain changes within 4-5 weeks. Among 136 HTX rats examined, 45 rats succumbed within 1 week after birth, 29 rats between 1-2 weeks, and 4 rats 27-44 days after birth. Out of 88 hydrocephalic rats 54 showed a marked ventricular dilatation, and 34 showed a mild dilatation. Dilatation of lateral ventricles was mild in the rats at 1-2 days after birth, but 3-14-day-old rats showed moderate or marked dilatation. 15-30 days after birth the rats developed mostly marked dilatation of lateral ventricles and third ventricle. Lateral ventricles and third ventricle showed a symmetric dilatation, but ependymal cell layers were well preserved. Aqueduct exhibited no dilatation in any rat. There were spongy appearances and cystic cavities in the white matter around the lateral ventricles. There were glial fibers and capillaries across the cystic cavities. Cystic lesions were also found in the deep subcortical white matter, consisting of spongy changes with extended extracellular spaces and microcysts in the white matter. Immunohistochemically, the anti-BBB reactivity in the normal control rats was at first weak at 2 weeks after birth and increased with the course of development, prominently 4 weeks after birth. Three- and four-week-old HTX rats with hydrocephalus showed moderate positive anti-BBB reaction in the cerebral cortex, the basal ganglia, and around the aqueduct but only a very weak reaction in the deep subcortical white matter and in the subependymal area of lateral ventricles. Laminin immunoreactivity was not different in the capillaries of hydrocephalic brain as compared with normal brain. Electron microscopically, tight junctions were well formed between endothelial cells of capillaries in the subcortical white matter. Occasionally capillaries with partial defect of basal membrane could be found, where the cytoplasm of endothelial cell was protruding between pericytic cytoplasm. Swelling of astrocytic end-feet were found around the microvessels. The results suggest that at the site of the lesion there is underdevelopment or immaturity of the blood-brain barrier.
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PMID:Immunohistochemical study on blood-brain barrier in congenitally hydrocephalic HTX rat brain. 782 77