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H Koide

Publications and source records attributed to H Koide.

At least 19 recordsLinked to original sources
PubMed1992

Recognition of an antiparallel beta-sheet structure of human epidermal growth factor by its receptor. Site-directed mutagenesis studies of Ala-30 and Asn-32.

The Ala-30 and Asn-32 residues involved in the major antiparallel beta-sheet structure of human epidermal growth factor (hEGF) were substituted with various amino acid residues, and the receptor-binding affinities of the nine variant hEGFs were determined by the use of human KB cells. The Ala-30----Arg, Ala-30----His and Ala-30----Phe substitutions drastically reduced the binding affinity, suggesting that the side chain in position 30 of Ala-30 of hEGF is required to be small for the receptor binding. The Asn-32----Asp substitution significantly reduced the binding affinity, while the Asn-32----His variant could bind to the receptor as well as to the wild-type hEGF. Therefore, it seems to be important for receptor binding that the side chain in position 32 does not have a negative charge but does have an NH group. Thus, we propose that, in the ligand-receptor complex, the receptor recognizes, on one side of the antiparallel beta-sheet structure of hEGF, a wider contact area than previously suggested.

Alanine↗
PubMed1992

A site-directed mutagenesis study on the role of isoleucine-23 of human epidermal growth factor in the receptor binding.

The isoleucine-23 residue of human epidermal growth factor (hEGF) was substituted by a variety of amino acid residues and the receptor-binding activities of variant hEGFs were determined by the use of human KB cell. Tight receptor binding was found of variants with hydrophobic amino acid residues in position 23. The size of the isoleucine residue was nearly optimum for the receptor binding as compared with other hydrophobic residues. The structure analysis by two-dimensional nuclear magnetic resonance spectroscopy showed that the substitution at position 23 only slightly affected the tertiary structure of hEGF. These indicate that the side chain of isoleucine residue in position 23, which is exposed on the protein surface, directly binds to a hydrophobic pocket of the receptor.

Amino Acid Sequence↗
PubMed1992

Isolation and characterization of delta-subspecies of protein kinase C from rat brain.

The delta-subspecies of protein kinase C (delta PKC) was purified to near homogeneity from the Triton X-100 extract of the rat brain particulate fraction by successive chromatographies on S-Sepharose fast flow, phenyl 5PW, heparin 5PW, hydroxyapatite, and Mono Q columns. The purified enzyme was a doublet with molecular masses of 78 and 76 kDa on SDS/PAGE. The doublet proteins were separated partially by Mono Q column chromatography; both were recognized by the antibodies raised against synthetic oligopeptides, parts of the deduced amino acid sequence of the rat delta PKC. Protein phosphatase 2A treatment suggested that the 78-kDa protein was a phosphorylated form of the 76-kDa protein. To confirm the structural and genetic identity of the doublet proteins, delta PKC was expressed in COS 7 cells by transfecting its cDNA-constructed plasmid and was purified for comparison. This recombinant enzyme was also a doublet. The enzymes isolated from the brain and COS 7 cells showed identical reactivities with delta PKC-specific antibodies, chromatographic behaviors, and V8 protease peptide mappings. In addition, these two enzyme preparations were indistinguishable from each other in their responses to phosphatidylserine, diacylglycerol, phorbol esters, free fatty acids, Ca2+, and enzyme inhibitors. Comparison was also made between the enzymologic properties of delta PKC and alpha PKC, which were distinctly different from each other.

Animals↗
PubMed1992

Isolation and characterization of the epsilon subspecies of protein kinase C from rat brain.

The epsilon subspecies of protein kinase C (epsilon PKC) was purified to near homogeneity from the soluble fraction of rat brain by successive chromatographies on DEAE-cellulose, threonine-Sepharose, phenyl-5PW, Mono Q, heparin-5PW, and hydroxyapatite columns. The enzyme from COS-7 cells that were transfected with an epsilon PKC cDNA expression plasmid showed the same elution profile. The purified enzyme from the brain was a double (96 and 93 kDa) on SDS/PAGE. Both the doublet proteins were recognized by antibodies raised against several oligopeptides that were parts of the deduced amino acid sequence of the rat brain epsilon PKC. When treated with potato acid phosphatase, both doublet proteins disappeared with the concomitant appearance of a single protein at 90 kDa, suggesting that epsilon PKC exists in the tissue as phosphorylated forms. The physiological significance of this phosphorylation is unknown. The enzymes from the rat brain and COS-7 cells were indistinguishable from each other in their kinetic and catalytic properties. Unlike alpha-, beta I-, beta II-, and gamma PKC, epsilon PKC was independent of Ca2+ but absolutely required phosphatidylserine and diacylglycerol for its activation; a tumor-promoting phorbol ester could replace diacylglycerol. epsilon PKC showed enzymological properties similar to those of delta PKC, except that epsilon PKC but not delta PKC was greatly activated by free arachidonic acid. Immunoblot analysis revealed that, in marked contrast to delta PKC, epsilon PKC is expressed predominantly in the brain tissue and only in trace amounts in heart, lung, spleen, thymus, and testis.

Alkaloids↗
PubMed1992

Characterization of protein kinase C in Xenopus oocytes.

Protein kinase C (PKC) was partially purified from Xenopus laevis oocytes by ammonium sulfate fractionation followed by DEAE-cellulose and hydroxyapatite column chromatography. In the latter chromatography, two distinct PKC activities were identified. Both PKC fractions contained an 80 kDa protein which was recognized by three antisera raised against the conserved regions of mammalian PKC. However, specific antisera against alpha, beta I, beta II, and gamma-subspecies of rat PKC did not recognize the protein. Kinetic properties of the Xenopus PKCs were very similar to those of the rat alpha PKC, and only a subtle difference was found in the mode of activation by arachidonic acid. When oocytes were treated with the tumor promoter, phorbol 12-myristate 13-acetate, one of the Xenopus PKCs was found to disappear very rapidly, while the other remained unchanged up to 2 hr.

Animals↗
PubMed1992

Oxidative metabolism of polymorphonuclear leukocytes (PMN) in patients with IgA nephropathy.

The production of hydrogen peroxide (H2O2) by neutrophilic polymorphonuclear leukocytes (PMN) after stimulation and the infiltration of PMN in glomeruli were determined in 20 patients with primary IgA nephropathy. The H2O2 production of PMN after the stimulation was measured with a spectrophotometer using horseradish peroxidase as substrate. The results were as follows: 1) when PMN were pretreated with cytochalasin B, H2O2 production after stimulation with heat-aggregated IgG (IgG) or serum-treated zymosan (STZ) was significantly higher in patients with IgA nephropathy than in controls, and 2) there was an increased amount of PMN localized in glomeruli in patients with IgA nephropathy using immunofluorescence of monoclonal anti-PMN antibody. It appeared that the increased renal infiltration of PMN which have a high potential for production of reactive oxygen species might induce the glomerular injuries in patients with IgA nephropathy.

Adult↗
PubMed1992

Purification of brush border membrane vesicles from rat renal cortex by size-exclusion chromatography.

Size-exclusion chromatography with controlled pore glass (CPG) was used in the further purification of renal brush border membrane vesicles (BBMV) isolated by the Ca precipitation method. The BBMV obtained had an almost spherical shape and their average diameter was about 95 nm in isotonic solution. The specific activities of alkaline phosphate and leucine aminopeptidase in the BBMV preparation were increased 18- and 17-fold, respectively, over those in the crude homogenate. The uptake of D-glucose by the purified BBMV in the presence of a sodium gradient reached 8.53 nmol/mg protein at 20 s. These results indicate that CPG chromatography is suitable procedure by which to obtain purified renal BBMV of homogenous size and with high specific marker enzyme activity for use in the study of membrane transport.

Animals↗
PubMed1992

Acute effects of angiotensin-converting enzyme inhibitor on erythrocyte sodium ion transport in essential hypertension.

The acute effects of angiotensin-converting enzyme inhibitor, captopril, on sodium ion transport systems were investigated in essential hypertensive and normotensive subjects. The passive sodium efflux through the erythrocyte membrane was significantly higher and erythrocyte sodium-potassium cotransport was lower in patients with essential hypertension when compared with normal subjects. However, sodium-potassium pump activity and sodium-lithium countertransport did not differ significantly between the hypertensive patients and the normal subjects. Immediately after captopril administration, erythrocyte passive sodium efflux and sodium-potassium cotransport returned to normal levels in the hypertensive subjects. Although the plasma renin activity and plasma aldosterone concentration were altered by captopril, they did not correlate with changes in any sodium transport system. These results suggest that the changes in sodium transport systems which occur immediately after captopril administration may contribute, at least in part, to its antihypertensive action.

Adult↗
PubMed1992

Renal platelet-derived growth factor gene expression in NZB/W F1 mice with lupus and ddY mice with IgA nephropathy.

The present study was carried out to determine how platelet-derived growth factor (PDGF)-A and -B chain mRNA expression correlate with disease activity in the renal cortex of NZB/W F1 mice, a model of systemic lupus erythematosus, and ddY mice, a model of IgA nephropathy. The PDGF-A and -B chain mRNA levels increased significantly as nephritis progressed in NZB/W F1 mice. In the renal cortex of ddY mice, however, the PDGF mRNA levels increased slightly with age. The PDGF mRNA levels in ddY mice were lower than those in NZB/W F1 mice. In the NZW control kidneys, the PDGF mRNA levels changed minimally throughout the experiments. A positive correlation was noted between PDGF mRNA levels and histopathological changes in renal tissues. At the onset of nephritis, NZB/W F1 mice were divided into two groups that received either methylprednisolone (MPSL) or saline injections for 5 months. The development of histopathological lesions and the increased PDGF mRNA levels were suppressed by MPSL treatment. These data suggest that PDGF plays a role in the progression of nephritis and that the beneficial effect of MPSL correlates with its ability to decrease the abnormally high PDGF mRNA levels seen in lupus nephritis.

Animals↗
PubMed1992

Possible mechanism of impaired calcium and vitamin D metabolism in nephrotic rats.

Patients who have nephrotic syndrome and normal renal function are hypocalcemic in spite of the elevated levels of serum parathyroid hormone (PTH) caused by a low serum concentration of 1,25-dihydroxyvitamin D[1,25(OH)2D], presumably because of its loss in urine. However, it has not been established whether the conversion of 25-hydroxyvitamin D[25(OH)D] into 1,25(OH)2D is impaired in the kidney. In this study, we examined the serum levels of vitamin D metabolites, and kinetics of renal 25(OH)D-1-hydroxylase activity in vitro, and nephrogenous cyclic AMP excretion in response to exogenous PTH administration in puromycin aminonucleoside-induced nephrosis in rats. Plasma ionized calcium and the serum levels of vitamin D metabolites were lower, and conversely, the serum PTH level was higher, in nephrotic rats than in controls. Serum 1,25(OH)2D levels were higher in 25(OH)D3-treated nephrotic rats than in untreated nephrotic rats, indicating that the low 1,25(OH)2D level in nephrotic rats is partially due to the low concentration of 25(OH)D. Although PTH levels were higher in nephrotic rats than in control rats, the Vmax of renal 25(OH)D-1-hydroxylase and nephrogenous adenosine 3',5'-monophosphate (cyclic AMP) excretion in response to exogenous PTH were significantly lower in nephrotic animals than in controls. These results suggest that abnormalities in calcium and vitamin D metabolism in nephrotic rats are partially attributable to impaired proximal tubular function.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1992

Perforin gene expression in T lymphocytes correlates with disease activity in immunoglobulin A nephropathy.

1. We studied perforin gene expression in T lymphocytes obtained from 26 patients with IgA nephropathy and from 15 healthy age-matched control subjects. 2. The majority of patients with IgA nephropathy (96%) had elevated perforin mRNA expression, whereas no perforin mRNA expression was detected in the T lymphocytes of normal control subjects. 3. A positive correlation was noted between perforin mRNA expression and urinary protein excretion. 4. Perforin mRNA expression correlated also with the histopathology in the renal tissue of patients with IgA nephropathy. 5. Sixty per cent of patients with grade III or IV histopathology had high perforin mRNA expression in T lymphocytes [more than (++)]. 6. These studies suggest that disregulation of perforin gene expression in T lymphocytes may be associated with the progression of IgA nephropathy and could be used as an indicator of disease activity.

Adolescent↗
PubMed1992

Glucocorticoid ameliorates altered gene expression of extracellular matrix components in kidneys of New Zealand black/white F1 mice.

1. We examined the effects of methylprednisolone on the levels of messenger RNA encoding for extracellular matrix components, including alpha 1(IV) collagen chain, laminin B1 and B2 chains, heparan sulphate proteoglycan and alpha 1(I) and alpha 1(III) collagen chains, and on the accumulation of these proteins in the renal cortex of New Zealand Black/White F1 mice. 2. At the onset of nephritis, at about 5 months of age, New Zealand Black/White F1 mice were divided in two groups that received either methylprednisolone or saline injections for 5 months. 3. The development of histological lesions and the glomerular deposition of IgG, IgM and C3 were suppressed by methylprednisolone treatment from 5 to 10 months of age. 4. The distribution and intensity of type IV collagen, laminin, heparan sulphate proteoglycan, type I collagen and type III collagen in renal cortex were decreased by the administration of methylprednisolone. 5. Levels of messenger RNA encoding for alpha 1(IV) collagen chain, laminin B1 and B2 chains, heparan sulphate proteoglycan and alpha 1(I) and alpha 1(III) collagen chains in the renal cortex of New Zealand Black/White F1 mice were significantly ameliorated at 8-10 months of age by methylprednisolone administration. 6. These results indicate that methylprednisolone treatment can serve as an effective therapeutic approach to abnormal extracellular matrix regulation in murine lupus nephritis.

Animals↗
PubMed1992

Cultural variations in premorbid personality of endogenous depression: a transcultural study.

The triplet Typus Melancholicus proposed by Tellenbach (1961), endogenous depression, a good response to antidepressants, seems to give a form of clearly defined entity. In this study comparing Typus Melancholicus in Japan and in France, we have tried to differentiate the essential elements which vary according to culture. Thirty-eight patients corresponding to major depression (DSM-III-R) hospitalized in our clinics in Japan and in France and their families have been questioned during and after the pathological episodes using a method of our own devising. In Japan, Typus Melancholicus is generally respected and socially well integrated because of its first characteristic, or "orderliness with consideration to others." For that reason in the premorbid life, it is usually free from manifest conflict, and its personality is remarkably homogeneous. In France the opposite is true with the range of variations being wide with a high frequency of neurotic aspects. This may be due to the malfunction of "the orderliness with consideration to others" in France, where individualism is dominant. We have found two general types of variants, named "hypercommon" and "hypernormative." These two directions correspond to the elements that compose Typus Melancholicus: patients of the first group have a tendency to adapt to other's point of view; patients of the second group have a tendency to be under the pressure of a sense of obligation toward norms.

Adult↗
PubMed1992

Some nosological considerations on "borderline case".

The so-called "borderline cases" are classified nowadays into Borderline Personality Disorder (BPD) or Schizotypal Personality Disorder (SPD) according to DSM-III-R. We discussed them as follows: The common pathology to them is their imaginary relationship to the object of identification. The difference between them is the distance from patients to their object. After presenting a case who is situated midway between the borderline case and neurosis, the pathology of borderline case can be described as a failure of repression. After classifying borderline cases in Japan into hysterical borderline or obsessional borderline, their relationship to hysterical neurosis and to obsessional neurosis are respectively discussed.

Adult↗
PubMed1992

Pseudodementia and delirium in depression: a contribution to psychosomatic medicine.

Presenting cases of depressional pseudodementia and delirium, we wish to point out the following points in this report. The patient in depression displays a state of pseudodementia when he is regarded as having senile dementia by the people around him. The depressed patient falls into delirium when he is embarrassed by an unexpected situation. In other words, the patient shows pseudodementia when he is continuously out of the world of daily meaning; he would fall into a disturbance of consciousness when he is suddenly put out of the world of meanings. This principle is applicable not only to depression but also to all mental diseases. In mental diseases, the symptoms themselves have some meaning for the patient. However, when the patient is put out of the world of ordinary meaning, mental disease presents the aspect of a somatic disease such as dementia or disturbance of consciousness.

Aged↗
PubMed1992

Gene expression of growth-related proteins and ECM constituents in response to unilateral nephrectomy.

To identify the specific regulatory mechanism associated with the events following unilateral nephrectomy, we measured the levels of mRNA encoding for extracellular matrix (ECM) constituents, for protooncogenes, and for proliferating cell nuclear antigen (PCNA) in renal cortex and glomeruli. One hour after left nephrectomy, c-jun and c-fos mRNA levels in renal cortex increased rapidly and then decreased rapidly to the control level, whereas c-myc and PCNA mRNA levels showed a slower and more sustained increase, with a peak at 6 h after nephrectomy, and then decreased to the control level after 7 days. mRNA levels for basement membrane components including alpha 1-chain of type IV collagen, laminin B1 and B2 chains, and heparan sulfate proteoglycan core protein were significantly increased in renal cortex at 12 h after nephrectomy, whereas those for interstitial collagens including alpha 1-chains of type I and type III collagen were unchanged following nephrectomy. On the other hand, the glomerular expression of all genes examined in this study showed little change during the experimental period. These results suggest that the time course of mRNA expression of ECM constituents is different from that of growth-related proteins in renal cortex and that glomerular mRNA levels for these components may not be associated with renal hypertrophy in the early stages following unilateral nephrectomy.

Animals↗
PubMed1992

Abnormal regulation of insulin-like growth factor gene expression in peripheral blood mononuclear cells from patients with IgA nephropathy.

We investigated insulin-like growth factor (IGF)-I and -II mRNA expression in peripheral blood mononuclear cells (PBMC) and T cells obtained from 31 patients with IgA nephropathy (IgAN), 43 patients with other types of glomerulonephritis and 16 health age-matched controls. The majority of patients with IgAN showed elevated IGF-I and -II mRNA expression in PBMC, while no IGF-I and -II mRNA expression was detected in PBMC obtained from patients with other types of glomerulonephritis or normal controls. In T cells obtained from IgAN, other types of glomerulonephritis and normal controls, however, IGF-I and -II mRNA expression was not detected. A positive correlation was noted between IGF-I and -II mRNA levels and urinary protein excretion. IGF-I and -II mRNA expression also correlated with the histopathological findings in the renal tissue of patients with IgAN. Sixty-nine percent of patients with more than 1.0 g/day proteinuria showed strong [more than (++)] IGF-I and -II mRNA expression in their PBMC. Eighty-one and 76% of patients with grade III and IV histopathological findings, respectively, showed strong IGF-I and -II gene expression in their PBMC. We also studied the clinical course of 11 patients with IgAN during hospitalization. The IGF-I and -II mRNA levels in these patients decreased gradually, as did proteinuria, after treatment. These studies suggest that abnormal regulation of IGF-I and -II gene expression in PBMC may be associated with the progression of IgAN and may be useful as an indicator of disease activity.

Adolescent↗