Five percent, 7.5% or 10% hypertonic saline prevents delayed neuronal death in gerbils

PURPOSE: To clarify the appropriate concentration and dose of hypertonic saline solution (HSS) for preventing delayed neuronal death in the hippocampal CA1 subfield after transient forebrain ischemia in gerbils. METHODS: Thirty gerbils were randomly assigned to five groups: physiological saline solution (PSS) group, ischemia/reperfusion treated with PSS 2 mL x kg(-1); 5% HSS group, treated with 5% HSS 2 mL x kg(-1); 7.5% HSS group, treated with 7.5% HSS 2 mL x kg(-1); 10% HSS group, treated with 10% HSS 2 mL x kg(-1); 20% HSS group, treated with 20% HSS 2 mL x kg(-1). Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes. Five days later, histopathological changes in the hippocampal area were examined, and the degenerative ratio of the pyramidal cells were measured according to the following formula: (number of degenerative pyramidal cells/total number of pyramidal cells per 1 mm of hippocampal CA1 subfield) x 100. RESULTS: In PSS and 20% groups, neuronal cell damage was observed five days after ischemia. In the other three groups, these changes were not observed. The degenerative ratios of pyramidal cells were as follows; PSS group: 91.6 +/- 5.6%, 5% HSS group: 7.2 +/- 1.6%, 7.5% group: 8.3 +/- 1.4%, 10% HSS group: 6.2 +/- 1.1%, 20% HSS group: 85.8 +/- 8.7% (P < 0.05; PSS and 20% HSS vs three other groups). CONCLUSION: This study demonstrates that 5, 7.5 or 10% HSS 2 mL x kg(-1) may prevent delayed neuronal death in the hippocampal CA1 subfield after cerebral ischemia/reperfusion in gerbils.     

Kindling of the visual cortex in cats: comparison with amygdaloid kindling

Kindling of the primary visual cortex (VC) was compared with that of the amygdala in cats. VC kindling was basically similar to kindling of the amygdala in that daily electrical stimulation can lead to the development of a generalized convulsion in most subjects, a growth of afterdischarges in their configuration and duration, and a reduction of the afterdischarge threshold. The kindling response of the VC differed from that of the amygdala in a number of respects, i.e., a high afterdischarge threshold, a different pattern of behavioral seizure development, an abrupt growth of electroclinical seizures coincident with the onset of a generalized convulsion, an intersubject variability in seizure susceptibility, and a marked seizure instability. In VC kindling the afterdischarge propagation into the amygdala was not observed until the generalized convulsion developed, and the early involvement of afterdischarge was seen in the pulvinar, lateral geniculate body, and superior colliculus. These data suggest that a neural mechanism different from amygdaloid kindling may participate in VC kindling, and that the subcortical structures of the visual system are involved in the preferential pathway for a seizure generalization from the VC.     

Biological and immunological studies on human tumor-associated cellular proteins detected by two-dimensional gel electrophoresis

Two tumor-associated cellular proteins, 82k/6.3 (MW/pI) and 61k/7.5, which were detected by two-dimensional gel electrophoresis, were studied by biochemical and immunological methods. In two-dimensional gel electrophoresis, 82k/6.3 and 61k/7.5 were rich in colon cancer tissue compared with normal colon mucosa, and they were also detected in fetal intestines. This shows that both proteins might be involved in category of oncofetal proteins. The localization of 82k/6.3 and 61k/7.5 was investigated by subcellular fractionation. They were rich in microsomal fraction, but not found in both nuclear and mitochondrial fractions. In binding reaction with seven kinds of lectins, 82k/6.3 reacted with RCAI, DBA and WGA, where 61k/7.5 reacted with RCAI, DBA, WGA, UEAI and SBA. Transferrin reacted with only RCAI. Each hybrid producing monoclonal antibody against 82k/6.3 or 61k/7.5 was generated by fusing spleen cells of BALB/c mice immunized by the two proteins and mouse myeloma cells. Each monoclonal antibody was specified in enzyme-linked immunoassay. In indirect immuno-fluorescent studies, monoclonal antibodies against 82k/6.3 and 61k/7.5 reacted with cytoplasma and membrane of human cancer cells. This result strongly suggests the localization of the two proteins demonstrated by subcellular fractionation.     

Morphological Analysis of the Early Development of the Chick Neural Tube Separated from the Floor Plate and Notochord

When the neural tube of avian embryos is separated from the notochord and floor plate, motoneurons in the spinal cord fail to develop. In order to investigate the factors involved in this phenomenon, cell proliferation activity and cell death were observed following paramedian incision of the neural tube at the level of the segmental plate using colchicine, BrdU, and TUNEL methods. If the notochord and/or floor plate produces a substance(s) that promotes cell division in the basal plate neuroepithelium or that supports the survival of the motoneuron's neuroblasts, mitotic figures should not be present in the neuroepithelium nor should substantial cell death be observed in the ventral aspect of the notochord- and floor plate-deprived neural tube. Surprisingly, however, neither result was observed in the present experiments, with the exception of a considerable amount of homogeneously distributed cell death. Neuroepithelial cells continued to proliferate and gave rise to neuroblasts. Nevertheless, motoneurons failed to develop, and the neural tube was enveloped by only the basement membrane of the alar plate (S. Hirano and H. Tanaka, 1994,Dev. Growth Differ.36, 481–488). These morphological results revealed that the cause of the development of the anterior horn lacking a neural tube in the notochord- and neural tube-eliminated embryos is not the elimination of the source of the surviving factor(s) of the motoneuron's neuroblasts, but rather the elimination of the signals to induce the motoneurons, derived from the notochord and/or floor plate. The larger amount of cell death in the neural tube on the experimental side suggests that a nonspecific survival factor(s), necessary for the survival of a variety of types of neuroblasts, is also produced by the notochord and/or floor plate.