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Biomedical subjects

A Kondo

Publications and source records attributed to A Kondo.

At least 577 records · Page 32Linked to original sources
PubMed1968

Immunotyping of different strains of Japanese encephalitis virus by antibody-absorption, haemagglutination-inhibition and complement-fixation tests.

The immunological characteristics of 26 strains of Japanese encephalitis virus (JEV) isolated in Japan and Malaya between 1935 and 1966 have been investigated mainly by the antibody-absorption variant of the haemagglutination-inhibition test, and to a certain extent also by conventional haemagglutination-inhibition and complement-fixation tests. The antibody-absorption technique shows promise as a routine method for the immunotyping of JEV.At present, two immunotypes can be distinguished. One comprises 2 strains, Nakayama-NIH and I-58, and is designated as the I-58 immunotype. The other immunotype, JaGAr 01, comprises 17 strains which share the characteristics of the JaGAr 01 strain, including one subline of the Nakayama strain, Nakayama-Yakken. The Nakayama-RFVL strain was found to have the characteristics of both immunotypes. The I-58 immunotype differs more markedly from related arboviruses, such as the Murray Valley encephalitis virus and the West Nile Eg101 strain, than does the JaGAr 01 immunotype.Evidence is presented which suggests that a given JEV strain can change immunotype on repeated passage through mice.

Animals↗
PubMedDate not supplied

Overproduction and purification of SulA fusion protein in Escherichia coli and its degradation by Lon protease in vitro.

To overproduce extremely unstable SulA protein, which is the cell-division inhibitor of Escherichia coli, we fused the sulA gene to the maltose-binding protein (MBP) fusion vectors with or without the signal sequence (plasmids pMAL-p-SulA and pMAL-c-SulA respectively). The amount of the full-length fusion protein expressed from the plasmid pMAL-p-SulA (pre-MBP-SulA) in E. coli was much larger than that expressed from the plasmid pMAL-c-SulA (MBP-SulA). A major amount of the pre-MBP-SulA fusion protein was expressed in a soluble form and affinity-purified by amylose resin. Since site-specific cleavage of the fusion protein with factor Xa resulted in the precipitation of SulA protein, the pre-MBP-SulA fusion protein was used to study the degradation of SulA protein by E. coli Lon protease in vitro. It was found that only the SulA portion of the fusion protein was degraded by Lon protease in an ATP-dependent manner. This result provides direct evidence that Lon protease plays an important role in the rapid degradation of SulA protein in cells.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

Affinity purification of fusion chaperonin Cpn60-(His)(6) from thermophilic bacterium Bacillus strain MS and its use in facilitating protein refolding and preventing heat denaturation.

The cpn60 gene from Bacillus strain MS, which is highly homologous to Bacillus stearothermophilus, was cloned. Cpn60 with a hexahistidine affinity tag (His)(6) fused to its C-terminus (cpn60-(His)(6)) was overproduced in Escherichia coli. Cpn60-(His)(6) was expressed in a soluble form in E. coli. and purified to homogeneity in a single step by nickel chelate affinity chromatography. Cpn60-(His)(6) formed a tetradecamer and had ATPase activity. Cpn60-(His)(6) mediated refolding of guanidine hydrochloride unfolded pig heart malic dehydrogenase (MDH) and Thermus flavus MDH at 25 and 70 degrees C, respectively, in an ATP-dependent manner. In addition, cpn60-(His)(6) prevented heat denaturation of pig heart MDH and T. flavus MDH at 30 and 80 degrees C, respectively, in an ATP-dependent manner. Therefore, cpn60-(His)(6) facilitates protein refolding and prevents heat denaturation of proteins across a wide temperature range.

Bacillus↗
PubMedDate not supplied

Development of a novel artificial matrix with cell adhesion peptides for cell culture and artificial and hybrid organs.

The authors present a novel artificial matrix with high cell adhesion and growth rate that was produced by chemical fixation of an RGD-containing peptide (Arg-Gly-Asp) on a polyvinyl alcohol (PVA) surface. The logical sequence behind the molecular design of an artificial matrix that mimics natural adhesive proteins, such as fibronectin, is based on the fact that an RGD tripeptidyl amino sequence is the minimal common adhesion site of adhesive proteins. Activation of surface hydroxyl groups by carbonyl diimidazole successfully incorporated GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro) onto PVA films. The resultant film surface was found to be bioactive, molecularly recognizing the adhesive receptor of bovine endothelial cells. Thus, the artificial matrix mimics active adhesion sites and serves as a novel artificial matrix that may be useful for cell culture, tissue-compatible implants, and hybrid artificial organs.

Animals↗
PubMedDate not supplied

Neurotoxicity in primary sensory neurons of adriamycin administered through retrograde axoplasmic transport in rats.

Neurotoxic effects of adriamycin (ADM) were examined in rats. The drug was administered through retrograde axoplasmic transport from the transected sciatic nerve in very small amounts (0.05 mg of adriamycin). Using the autofluorescence specific to adriamycin as a histological tracer, alterations in primary sensory neurons in dorsal root ganglia (DRG) and in motor neurons in the spinal cord were observed chronologically by light and electron microscopy. In the DRG at the fifth and sixth lumbar levels, small neurons initially showed alterations in mitochondria, wavy nuclear membranes and enlarged cisternae of rough endoplasmic reticulum, and disappeared early in the experiments. Large neurons, which showed accumulation of neurofilaments, dense bodies and vacuoles in the perikarya in addition to nucleolar and nuclear chromatin alterations, degenerated slowly. In contrast, motor neurons in the anterior horn at the sixth lumbar level survived throughout the administration of adriamycin despite the presence of transient weak adriamycin autofluorescence and vacuoles in the cytoplasm. Thus, the susceptibility and vulnerability of motor neurons in spinal cord to adriamycin differed from that of primary sensory neurons; small neurons in the DRG were more susceptible than large sensory neurons. Administration through retrograde axoplasmic transport proved to be a useful technique for the evaluation of the neurotoxicity of adriamycin without the complications of systemic effects.

Animals↗
PubMedDate not supplied

Selective expression of Ser 199/202 phosphorylated tau in a case of frontotemporal dementia.

We examined a 65-year-old patient with clinicopathological features that met the criteria of frontotemporal dementia (FTD), particularly frontal lobe degeneration (FLD). He came from a family with concentrated occurrence of dementia symptoms in the presenium. Neuropathological examination disclosed brain atrophy locally pronounced on the frontotemporal lobes with characteristic neuronal loss, microvacuolation and astrocytic gliosis. There were no pathological hallmarks such as senile plaques, Pick bodies (PBs), achromatic cells and neurofibrillary tangles. Precise separation of FTD from Pick disease (PD) and motor neuron disease with dementia (MNDD) has not yet been established, and they are included in one spectrum. Antibodies against paired helical filament tau protein demonstrated immunopositive cytoskeletal structures within the neurons as well as the glial cells in the brain of the present case. They were selectively stained with tau 199/202 but not tau 396, which were provided newly to recognize phosphorylation at Ser 199/202 or Ser 396 in tau, respectively. We investigated tau pathology in the present case in comparison to 8 cases with PD that were clinicopathologically confirmed. Neither tau 199/202 nor tau 396 stained the CNS structures in PD cases with few PBs, while both stained evidently those as well as PBs in PD cases associated with many PBs; so that the present case could be distinguished from PD on the basis of the immunoreactivity to site-specific phosphorylated tau. Our result suggests that FTD, especially familial FLD type might involve unique tau pathology, no matter whether FLD is a distinct entity from PD, or a variant form in the wide FTD spectrum including PD and MNDD and other related disorders.

Adult↗
PubMedDate not supplied

Subpial amyloid plaques in the cerebellum in a case of Alzheimer's disease.

We studied the morphological and immunohistochemical characteristics of subpial amyloid plaques (SAPs), which were found particularly in the cerebellum of an Alzheimer's disease (AD) patient, and compared them to the senile plaques (SPs) and amyloid angiopathy in AD cerebrum. The case presented herein exhibited a variety of amyloid deposition including SAPs and amyloid angiopathy. SAPs were visualized most intensely with antibodies to amyloid-beta protein (A beta), compared with the conventional staining methods including silver impregnation techniques. The most unique feature of the SAPs consisted in their morphology and location, which was between the pia mater and brain parenchyma, occasionally bulging outside the brain surface. Immunostaining with monoclonal antibodies against the carboxyl termini of A beta showed that SAPs were invariably positive for A beta 42/43, two-thirds of which were associated with A beta 40. Ultrastructurally SAPs appeared either fibrillar or amorphous and were separated originally from the brain parenchyma by sheets of glia limitans. The chronological relationships in the evolution of the SAPs are discussed with relevance to their morphology and location.

Aged↗
PubMedDate not supplied

Sequential changes of tau-site-specific phosphorylation during development of paired helical filaments.

It has been reported that many tau sites in neurofibrillary tangles (NFT) are abnormally phosphorylated. We investigated the phosphorylation of tau in the hippocampus of nondemented patients and Alzheimer's disease patients by immunostaining with five site-specific antibodies against phosphorylated tau. In the pretangle stage, tau in neuropil threads was phosphorylated at serines 199, 202 and 409, numbered according to the longest human tau isoform, whereas tau in some neuronal soma was phosphorylated at serines 199, 202, 409 and 422. Tau at the stage of NFT was phosphorylated at serine 396 and threonine 231 in addition to serines 199, 202, 409 and 422. In the advanced stage, tau in ghost tangles was phosphorylated mainly at serine 396. These results suggest that the phosphorylation of each site in tau differs among the maturing stages of neurofibrillary change and that abnormal phosphorylation of tau in the neuronal soma occurs at 199, 202, 409 and 422 earlier than at threonine 231 and serine 396.

Adult↗
PubMedDate not supplied

Nuclear accumulation of p53 protein in gastric cancer strongly correlates with enlargement of nuclear area of cancer cells.

The nuclear area (NA) of cancer cells have been reported to be a useful prognostic indicator in various tumors. However, this image analysis of cancer nucleus has only rarely been applied to gastric adenocarcinoma. Moreover, it remains to be shown what types of biological factors influence this nuclear feature. In this study, we analyzed the area of cancer nuclei in tumors from 97 patients with advanced gastric cancer (t3, n0, stage II) by using hematoxylin and eosin stained slides with a computer-assisted image-analysis system. The morphometric data were compared with clinicopathological and biological status of the tumors. The mean NA of 50 tumors with venous invasion (50 microm2) was significantly larger than that of 47 tumors without venous invasion (38 microm2, p<0.0001). There was a significant correlation between the NAs of cancer cells and the p53 labeling indices of tumors (p=0.0012) and Ki-67 labeling indices of tumors (p=0.0324). However, no significant correlation was detected between the NAs of cancer cells and other factors, such as, tumor size, DNA ploidy pattern, expression of vascular endothelial growth factor (VEGF), or microvessel density of tumors. The five-year survival rate of 49 patients with large nuclear area (NA > or =41 microm2, 63%) was significantly lower than that of 48 patients with small nuclear area (NA <41 microm2, 78%, p=0.043). Data from computerized morphometry are objective and can be obtained rapidly by conventional microscopic analysis. The NA of cancer cells in advanced gastric cancer appears to predict the ability to invade the microvessels in the gastric wall. This nuclear morphological feature strongly correlated with p53 accumulation in the nuclei of gastric adenocarcinoma.

Cell Nucleus↗