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Biomedical subjects

H Kondo

Publications and source records attributed to H Kondo.

At least 19 recordsLinked to original sources
PubMed1992

Identification of the fatty acid binding site on glutathione S-transferase P.

Glutathione S-transferase P (GST-P) bound a series of endogenous fatty acids (C12-C18). To clarify the function and the binding site of the fatty acids, interaction between fatty acids and GST-P was investigated by using 12-(9-anthroyloxy) stearic acid conjugated with Woodward's reagent K. The fluorescence-conjugated fatty acid noncompetitively inhibited GST activity. After GST-P was covalently labeled with the fatty acid, the enzyme was digested with Lysyl Endopeptidase. From the peptide mapping, a single fluorescence-labeled peptide was obtained. By the sequence analysis, the peptide binding fatty acid was determined as the residues of 141-188 from the amino terminus.

Affinity Labels↗
PubMed1992

Thrombin accumulation in brains of patients with Alzheimer's disease.

Thrombin was detected immunohistochemically in brain tissue of Alzheimer's disease (AD) patients and age-matched controls. Positive staining was restricted to vessels and residual plasma in controls but was also present in senile plaques, some diffuse amyloid deposits and neurofibrillary tangles in AD. Positive staining was abolished by absorption of antibody with purified human thrombin but not by absorption with prothrombin. The data suggest that thrombin formation from prothrombin probably takes place in AD brain.

Aged↗
PubMed1992

Localization of mRNA for beta-adrenergic receptor kinase in the brain of adult rats.

A cDNA encoding rat beta-adrenergic receptor kinase (beta-ARK) was cloned and sequenced. By in situ hybridization histochemistry of adult brain, beta-ARK mRNA was expressed intensely in the cerebellar granule cell layer and moderately in the hippocampal pyramidal cells and dentate granule cells. The neocortex and piriform cortex expressed it moderately to weakly, whereas the thalamus and hypothalamus expressed it weakly to faintly. No significant expression of the mRNA was detected in the caudate-putamen. Weak expression of beta-ARK mRNA was detected in several nuclei of the brainstem and in the spinal gray matter.

Animals↗
PubMed1992

Doxorubicin: an antagonist of muscarinic receptors in guinea pig heart.

While studying the mechanisms of doxorubicin-induced cardiotoxicity, we observed that doxorubicin inhibited the negative inotropic effect of acetylcholine in isolated heart muscle preparations. We therefore examined the effects of doxorubicin on muscarinic acetylcholine receptors. In left atrial muscle preparations isolated from guinea pig heart and stimulated at 2 Hz at 30 degrees C, doxorubicin caused a parallel right-ward shift of the dose-response curves for the negative inotropic effects of acetylcholine. The inhibitory action was reversed by an additional incubation in the absence of doxorubicin. Doxorubicin reversed the carbachol-induced inhibition of developed tension: a high concentration of doxorubicin brought the force back to its original strength. Doxorubicin inhibited specific [3H]quinuclidinyl benzilate (QNB) binding to membrane preparations obtained from ventricular muscle of guinea pig hearts. The pA2 value for doxorubicin obtained in the inotropic study corresponded to the IC50 value for doxorubicin observed in the [3H]QNB binding assay. These results indicate that doxorubicin acts as a weak competitive antagonist on muscarinic acetylcholine receptors.

Animals↗
PubMed1992

Expression of necdin, an embryonal carcinoma-derived nuclear protein, in developing mouse brain.

Necdin is a polypeptide sequence encoded by neural differentiation-specific mRNA derived from embryonal carcinoma cells. We have examined the expression of necdin and its mRNA in cultured cells and mouse brain by Northern blot analysis and immunohistochemistry. Among various established cell lines including neuroblastoma and glioma cells, only differentiated embryonal carcinoma cells (P19 and F9) expressed necdin mRNA. Necdin immunoreactivity was localized in the nuclei of differentiated neurons derived from P19 cells. Necdin mRNA was detected throughout brain regions of adult mouse; the relative abundances in the hypothalamus and midbrain were the highest, whereas those in the olfactory bulb and cerebellum were the lowest. In developing mouse brain, necdin mRNA was expressed during early periods of neuronal generation and differentiation, and the peak levels were attained during postnatal days 1-4. Necdin immunoreactivity was not detected in the neural stem cells on embryonic day 10, but was concentrated in the nuclei of brain cells, mostly neurons, at advanced stages of differentiation. The majority of differentiated neurons in the brain had necdin-immunoreactive nuclei on postnatal day 33. Thus, necdin may represent a valuable molecular marker for differentiated neurons both in vitro and in vivo.

Amino Acid Sequence↗
PubMed1992

Push-pull modulation of ganglion cell responses of carp retina by amacrine cells.

The responses of a ganglion and an amacrine cell were recorded simultaneously in the carp retina. Sinusoidal current injected into amacrine cells modulated ganglion cell discharges either in phase (excitation) or in opposite phase (inhibition). ON-center ganglion cells received excitatory inputs and OFF-center ganglion cells received inhibitory inputs from ON-center amacrine cells. They received inputs of opposite polarity from OFF-center amacrine cells. Namely, inputs from ON-center and OFF-center amacrine cells augment the responses of ON-center and OFF-center ganglion cells in a push-pull manner.

Animals↗
PubMed1992

Assay of gamma-glutamyltransferase with amino acid dehydrogenases from Bacillus stearothermophilus as auxiliary enzymes.

A spectrophotometric assay for serum gamma-glutamyltransferase (gamma-GT, EC 2.3.2.2) based on the increasing absorbance at 340 nm due to NADH formation is described. Using gamma-glutamyl dipeptides as the donor substrate, amino acids formed by the gamma-glutamyl transfer from the donor substrate to the acceptor substrate glycylglycine are stoichiometrically converted by the corresponding amino acid dehydrogenases from Bacillus stearothermophilus to produce their keto acids and NADH. gamma-Glutamylalanine was found to be the most specific and sensitive donor substrate. The method can be mechanized, is free of interference and correlates well with conventional methods.

Amino Acid Oxidoreductases↗
PubMed1992

Localization of gene expression of calbindin in the brain of adult rats.

Localization of gene expression of calbindin, a cytosolic calcium-binding protein, was examined throughout the adult rat brain by in situ hybridization with cDNA probes. The gene was expressed most intensely in the Purkinje cells in the cerebellum, intensely in the granule cells of the dentate gyrus, and moderately in the inferior olivary nucleus, in the nuclei of the trapezoid body, in the medial part of the lateral habenular nuclei, entorhinal cortex and in the mammillary nuclei. In addition, weak expression of the gene was widespread in the forebrain and brainstem gray matter, and also in small cells in the spinal posterior horn as well as the ependymal cells. The widespread and heterogeneous expression of the gene in the brain suggests that calbindin is differentially involved in calcium-regulated phenomena in different neurons.

Animals↗
PubMed1992

Inhibitory effect of oryzacystatins and a truncation mutant on the replication of poliovirus in infected Vero cells.

Poliovirus, a picornavirus family member, requires the processing of its poly-protein by its own cysteine proteinase for replication. Oryzacystatin-I and oryzacystatin-II, proteinaceous cysteine proteinase inhibitors (cystatins) of rice seed origin, were found to inhibit the replication of poliovirus effectively in infected Vero cells in vitro. Truncated oryzacystatin-I, which lacks the NH2-terminal 25 amino acid residues of the intact protein, is an even more effective inhibitor, eliciting its effect at concentrations of less than 0.25 nmol/ml. The low molecular weight cysteine proteinase inhibitors, E-64, E-64C and loxistatin, showed no anti-viral effect at any concentration investigated.

Animals↗
PubMed1992

Species-specific differences in the mitogenic activity of heparin-binding growth factors in the sera of various mammals.

Sera from different mammalian species displayed great differences in mitogenic activity, as measured by stimulation of DNA synthesis in BALB/c 3T3 cells (3T3 cells). Among the sera examined, fetal bovine serum was least active, and increasing activity was detected in calf serum, human serum, rat serum and mouse serum, in that order. Rat and mouse sera exhibited extremely high mitogenic activity with 3T3 cells, but when TIG-1 human fetal lung fibroblasts were used for the DNA assay instead, the activity levels of all of the sera were lower, and the differences between them were smaller. To determine the reasons for these differences, the heparin-binding growth factors in each serum were separated on a heparin affinity column. Five peaks of DNA-stimulating activity were obtained. Three of these were found in all sera examined, with both 3T3 cells and TIG-1 cells. Two other peaks were found only with 3T3 cells; one was peculiar to rat and mouse sera, with extremely high activity in the rat, and the other was specific to fetal serum. The dependence of the activity of these peaks on the cells used for the test was confirmed using normal rat lung fibroblasts and immortalized rat kidney cells. These findings adequately explain the species-specific differences in mitogenic activity of whole sera, and the variation in activity depending on the cells used for assay of DNA synthesis.

3T3 Cells↗
PubMed1992

Nerve growth factor receptor (NGFR)-like immunoreactivity in the perineurial cell in normal and sectioned peripheral nerves of rats.

The occurrence of nerve growth factor receptor (NGFR)-like immunoreactivity in the perineurial cells of sympathetic and sensory nerves was analyzed in normal controls and after surgical severance. In the normal nerve trunk, no cellular elements exhibited NGFR-like immunoreactivity. Immunoreactivity was induced in the innermost perineurial cells and in all Schwann cells distal to a severed nerve. The acquisition of immunoreactivity in perineurial cells was also seen in deafferented sympathetic ganglia. On the other hand, the perineurial cells as well as axonal endings showed NGFR-like immunoreactivity consistently in the terminal region of normal nerves, and this immunoreactivity was enhanced by nerve section. The present study clearly showed that different types of nerve terminals are ensheathed to different extents by perineurial cells which were first clearly identified by their NGFR-like immunoreactivity: 1) nerve terminals were free of the perineurium far away from targets in the iris, 2) they were free of the perineurium at sites close to targets in the lingual epithelium, and 3) the perineurium ensheathed nerve terminals together with targets in Meissner's sensory corpuscle. The functional significance of the three different patterns of perineurial enclosure requires further examination.

Animals↗
PubMed1992

Production of interleukin 8 by cultured synovial cells in response to interleukin 1 and tumor necrosis factor.

Both interleukin 1 alpha (IL-1 alpha) and tumor necrosis factor alpha (TNF alpha) stimulated the production of interleukin 8 (IL-8) by synovial cells in time and dose dependent manners. Enhanced chemotactic activity of polymorphonuclear cells (PMN) in culture supernatants of synovial cells was neutralized with anti-IL-8 antibody, thus showing synovial cells to be capable of secreting IL-8 which may contribute to PMN accumulation in rheumatoid inflamed joints.

Cells, Cultured↗
PubMed1992

Transient appearance of Ca-binding protein (spot 35-calbindin) in bronchial epithelial cells, thyroid parafollicular cells and thymic epithelial cells during the development of rats.

Tracheobronchial epithelium, thyroid organ, thymus, of the developing rats were examined by immunohistochemistry using anti-spot 35 calbindin-antiserum. At E 14, weak to moderate immunoreactivity for spot 35-calbindin was detected in the airway epithelia of the distal half of the trachea and the extrapulmonary bronchus. The immunoreactive cells increased in intensity at E 16-E 21, but decreased markedly after birth. These cells were non-ciliated cells and comprised a majority of the epithelial cells especially in the ventral/cartilaginous portion of the airway. They were characterized by microvilli, vacuoles, granular and agranular endoplasmic reticulum. Typical ciliated cells, which were much less numerous than the immunopositive non-ciliated cells, were immunonegative. In thyroid gland, calbindin-immunoreactive cells first appeared at E 18. They increased in number at E 20-P 1 and decreased gradually after P 7. These cells were the parafollicular cells characterized by numerous secretory granules and situated in close proximity to the basal surface of the follicular cells. In the thymus, immunoreactive cells appeared in the thymic medulla at E 20. They increased in number at P 1, but decreased gradually after P 7. They were stellate in shape and had vesicles, vacuoles, intermediate filaments and represented a subpopulation of thymic reticular epithelial cells. Such a transient appearance of spot 35-calbindin in these cells suggests that this protein may be involved in the regulation of differentiation or may be involved in the process of secretion during the limited developmental period.

Animals↗
PubMed1992

Localization of gastrin-releasing peptide (GRP)-like immunoreactivity in the lysosomal compartment of the trigeminal ganglion cells of the rat.

Cellular and subcellular localizations of gastrin-releasing peptide-like immunoreactivity (GRP-LI) were examined in the perikarya of trigeminal ganglion cells. By immunolight microscopy using semi-thin sections, GRP-LI was observed in almost all the neuronal somata with various intensity as granular profiles distributing widely in the cytoplasm. By immunoelectron microscopy using ultrathin frozen sections and protein A-gold, GRP-LI was found predominantly in rounded or oval membrane-bound structures which were 300-800 nm in diameter and displayed various electron-density and heterogenous contents. Double-labeling immunoelectron microscopy using antibodies for GRP and cathepsin L, a well-characterized lysosomal proteinase, clearly demonstrated that these GRP-immunoreactive intracytoplasmic structures were lysosomes. In contrast, GRP-LI was detected only occasionally in the large granular vesicles (100-200 nm in diameter). These findings strongly suggest that considerable amount of GRP or GRP-like peptide is subject to intracellular degradation in the lysosome rather than to the regulatory secretion pathway, and this is the reason why no fibers immunoreactive for GRP have been detected in the peripheral sensory field.

Animals↗
PubMed1992

Selective loss of nigral neurons in Alzheimer's disease: a morphometric study.

Loss of neurons from the substantia nigra (SN), which is sometimes observed in Alzheimer's disease (AD), was quantitatively analyzed in 10 cases of presenile AD and 19 age-matched controls. On sections from the upper and lower portions of the SN, the pigmented zone (zona compacta) and the non-pigmented zone (zona reticulata) were delineated, and these zones were partitioned into quarters: medial, mid-medial, mid-lateral and lateral. This approach clarified topographical preference of neuronal depletion in the SN of AD; namely (1) pigmented neurons were more severely affected than non-pigmented neurons, (2) neuronal depletion was more marked in the lower SN (-38%, P less than 0.001), where the pigmented neurons in the medial quarter were most severely affected (-51%, P less than 0.001), (3) in the upper SN (neuronal loss: -21%, P less than 0.01), the pigmented neurons in the mid-medial quarter were most severely affected (-43%, P less than 0.01). These findings suggest that some groups of nigral neurons are primarily involved in presenile AD. Gallyas staining after bleaching of melanin pigments uncovered a large number of neurofibrillary tangles (NFTs) mainly in the pigmented zone, especially in the medial quarter. A large number of NFTs, scarse senile plaques, and substantial depletion of neurons form an unique combination of Alzheimer pathology in the SN not well recognized so far.

Aged↗
PubMed1992

Role of iron in oxidative stress in skeletal muscle atrophied by immobilization.

To clarify the role of iron in oxidative stress in skeletal muscle atrophied by immobilization, we investigated the effect of deferoxamine--an iron-chelating agent. Deferoxamine, iron-saturated deferoxamine and double-distilled water (control) were administered subcutaneously from the 4th day after immobilization via osmotic pumps to male Wistar rats (14 weeks old), one ankle joint of which was immobilized in the extended position. After 12 days' immobilization, soleus--typical slow red muscles were collected from both hind limbs and their levels of thiobarbituric acid-reactive substance (TBARS) and glutathione were measured. Deferoxamine suppressed the increase of TBARS and glutathione disulfide in atrophied muscle while iron-saturated deferoxamine did not, which strongly suggests that the iron-chelating action of deferoxamine suppressed the increased oxidative stress. This means that iron plays a very important role in increasing oxidative stress in atrophied muscle. In addition, deferoxamine decreased the degree of atrophy, an effect thought to be mediated by the suppression of oxidative stress.

Animals↗
PubMed1992

Multiple endocrine neoplasia type 2 with malignant pheochromocytoma--long term follow-up of a case by 131I-meta-iodobenzylguanidine scintigraphy.

The case of a 33-year-old Japanese man, who has Multiple Endocrine Neoplasia Type 2 (MEN IIa) (Sipple's syndrome) with malignant pheochromocytoma, is reported. He had survived for twelve years since the initial diagnosis of malignant pheochromocytoma. Within this period, he had undergone 131I-meta-iodobenzylguanidine scintigraphy twice, in 1983 and 1990. This is the first case in Japan of a longterm surviving patient with malignant pheochromocytoma followed up by 131I-MIBG scintigraphy. Although he had no exacerbation of clinical symptoms or urinary catecholamine levels, second scintigraphy clearly showed an increase in the tumor size, new metastasis of the malignant pheochromocytoma and exacerbation of the medullary thyroid carcinoma. Compared with any other roentgenological device and hormonal data, 131I-MIBG scintigraphy was seen to be a good tool for evaluating the localization and the progression of tumors. 131I-MIBG scintigraphy is a useful procedure not only for initial diagnosis but also for judging progression in a case of advanced malignant pheochromocytoma.

3-Iodobenzylguanidine↗