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Biomedical subjects

M Higuchi

Publications and source records attributed to M Higuchi.

At least 235 records · Page 13Linked to original sources
PubMed1992

A case of IgA nephritis showing diffuse podocytic detachment from the glomerular basement membrane.

We report the case of a 15-year-old Japanese female with severe mesangial proliferative IgA glomerulonephritis who showed a dramatic response to cocktail therapy for nephrotic syndrome. She had suddenly developed massive proteinuria and microscopic hematuria. The first renal biopsy at one month after onset revealed severe mesangial hypercellularity and podocytic detachment from the glomerular basement membrane (GBM). The cocktail therapy resulted in a decrease of proteinuria clinically, and a second biopsy demonstrated repair of the podocytic detachment. We suggest that the massive proteinuria in this case was due to destruction of the size barrier by detachment of podocytes from the GBM, and the repair of the podocytic covering on the GBM was accelerated by the cocktail therapy.

Adolescent↗
PubMed1991

Molecular characterization of mild-to-moderate hemophilia A: detection of the mutation in 25 of 29 patients by denaturing gradient gel electrophoresis.

To date it has been difficult to characterize completely a genetic disorder, such as hemophilia A, in which the involved gene is large and unrelated affected individuals have different mutations, most of which are point mutations. Toward this end, we analyzed the DNA of 29 patients with mild-to-moderate hemophilia A in which the causative mutation is likely to be a missense mutation. Using computer analysis, we determined the melting properties of factor VIII gene sequences to design primer sets for PCR amplification and subsequent denaturing gradient gel electrophoresis (DGGE). A total of 45 primer sets was chosen to amplify 99% of the coding region of the gene and 41 of 50 splice junctions. To facilitate detection of point mutations, we mixed DNA from two male patients, and both homoduplexes and heteroduplexes were analyzed. With these 45 primer sets, 26 DNAs containing previously identified point mutations in the factor VIII gene were studied, and all 26 mutations were easily distinguishable from normal. After analyzing the 29 patients with unknown mutations, we identified the disease-producing mutation in 25 (86%). Two polymorphisms and two rare normal variants were also found. Therefore, DGGE after computer analysis is a powerful method for nearly complete characterization of disease-producing mutations and polymorphisms in large genes such as that for factor VIII.

Base Sequence↗
PubMed1991

Haemophilia A: database of nucleotide substitutions, deletions, insertions and rearrangements of the factor VIII gene.

Mutations at the factor VIII gene locus causing Haemophilia A have now been identified in many patients from many ethnic groups. Earlier studies used biased methods which detected repetitive mutations at a few CG dinucleotides. More recently rapid gene scanning methods have uncovered an extreme diversity of mutations. Over 80 different point mutations, 6 insertions, 7 small deletions, and 60 large deletions have been characterised. Repetitive mutation has been proved for at least 16 CpG sites. All nonsense mutations cause severe disease. Most missense mutations appear to cause instability of the protein, but some are associated with production of dysfunctional factor VIII molecules, thereby localising functionally critical regions of the cofactor. Variable phenotype has been observed in association with three of the latter class of genotype. This catalogue of gene lesions in Haemophilia A will be updated annually.

Base Sequence↗
PubMed1991

Molecular characterization of severe hemophilia A suggests that about half the mutations are not within the coding regions and splice junctions of the factor VIII gene.

Hemophilia A is an X chromosome-linked disorder resulting from deficiency of factor VIII, an important protein in blood coagulation. A large number of disease-producing mutations have been reported in the factor VIII gene. However, a comprehensive analysis of the mutations has been difficult because of the large gene size, its many scattered exons, and the high frequency of de novo mutations. Recently, we have shown that nearly all mutations resulting in mild-to-moderate hemophilia A can be detected by PCR and denaturing gradient gel electrophoresis (DGGE). In this study, we attempted to discover the mutations causing severe hemophilia A by analyzing 47 unselected patients, 30 of whom had severe hemophilia and 17 of whom had mild-to-moderate disease. Using DGGE as a screening method, we analyzed 99% of the coding region, 94% of the splice junctions, the promoter region, and the polyadenylylation site of the gene. We found the mutation in 16 of 17 (94%) patients with mild-to-moderate disease but in only 16 of 30 (53%) patients with severe hemophilia A. Since DGGE after computer analysis appears to detect all mutations in a given fragment, the lower-than-expected yield of mutations in patients with severe disease is likely not due to failure of the detection method; it is probably due to the presence of mutations in DNA sequences outside the regions studied. Such sequences may include locus-controlling regions, other sequences within introns or outside the gene that are important for its expression, or another gene involved in factor VIII expression that is very closely linked to the factor VIII gene.

Amino Acid Sequence↗
PubMed1991

Effects of norepinephrine on hypoperfusion-reperfusion injuries in hearts isolated from normal and diabetic rats.

Contractile and energy-metabolic functions were investigated in paced hearts isolated from normal (Normal) and streptozotocin-diabetic rats (DM) during hypoperfusion at 1 ml/min with or without 10(-6) M norepinephrine (NE) and during reperfusion at the pre-hypoperfusion flow. Left ventricular pressure (LVP) and contractile force (CF) were monitored, respectively, through a water-filled balloon in LV and through a hook attached to the apex. A 1-h hypoperfusion without NE caused significant elevations in resting LVP and resting CF only in DM hearts, smaller transmural lactate accumulations in DM hearts, and similar ATP decreases in both groups. Significant decreases in developed LVP and developed CF were observed in both groups. NE during hypoperfusion caused deterioration of these cardiac dysfunctions in both groups, particularly in DM hearts. A 1-h reperfusion caused elevations in resting LVP and resting CF with no recovery in developed CF in Normal hearts, while it caused partial recovery in resting and developed CF in DM hearts. Both groups showed similar partial recovery of ATP. NE during hypoperfusion improved the mechanical dysfunction during reperfusion in DM hearts, but there was a smaller recovery in ATP than in hearts without NE. In vivo insulin treatment in DM restored the cardiac functions to Normal levels. Thus, DM hearts were more vulnerable to hypoperfusion, while Normal hearts were more vulnerable to reperfusion injury.

Animals↗
PubMed1991

TNF-mediated cytotoxicity. Importance of intracellular cGMP level for determining TNF-sensitivity.

Previous work on the cytolytic action of activated macrophages indicated that tumor necrosis factor (TNF) showed synergistic cytolytic activity with NO, which has been shown to act as a cyclic GMP (cGMP) generator [Higuchi et al., J. Immun. 144, 1425-1431, (1990)]. In this study, we investigated the relationship between the accumulation of intracellular cGMP and the cytotoxic action of TNF. It was demonstrated that TNF-mediated cell lysis was closely related to the background level of intracellular cGMP, and that the accumulation of cGMP within TNF resistant cells induced TNF sensitivity. We reached these conclusions on the basis of the following results; (1) agents (sodium nitroprusside and isobutylmethylxantine) that cause the accumulation of cGMP intracellularly increased the TNF-sensitivity of TNF-resistant cells; (2) the addition of dibutyryl cGMP to TNF-resistant cells increased the TNF-sensitivity; and (3) treatment at 40 degrees C or agents such as interferon gamma and actinomycin D, that synergistically kill tumor cells together with TNF, potentially increased the cGMP level. Therefore, intracellular cGMP may be one of the key molecules that lead to cell death caused by TNF.

Animals↗
PubMed1991

An analysis of positive inotropic effects of nitroglycerin in the canine hearts.

1. Nitroglycerin caused dose-dependent increases in regional myocardial contractile force (MCF) in open-chest dogs, along with dose-dependent decreases in left ventricular end-diastolic (LVEDP) and arterial pressures and an increase in plasma catecholamines level. 2. The increase in MCF could not be completely prevented by propranolol along with a slight decrease in LVEDP and no increase in heart rate, although a nifedipine-produced increase in MCF without a significant decrease in LVEDP disappeared with propranolol despite the same decrease in arterial pressure.

Animals↗
PubMed1991

Combined anti-interleukin-2 receptor and low-dose cyclosporine therapy in experimental autoimmune uveoretinitis.

The effect of combination treatment with anti-interleukin-2 (IL-2)-receptor monoclonal antibody (ART18) and cyclosporine A (CsA) on the effector stage of experimental autoimmune uveoretinitis (EAU) was examined. Efferent-stage EAU was induced in Lewis rats by adoptive transfer of a T-helper cell line specific to retinal soluble antigen (SAg). Rats were treated with ART18 (0.5 mg/kg/day), low dose CsA (1.5 mg/kg/day), or a combination of both. The results were compared to groups treated with high dose CsA (10 mg/kg/day) and to sham-treated animals, with respect to clinical and histological EAU, lymphocyte proliferative responses to SAg, and the ability to transfer EAU to secondary recipients. Ten-day combination therapy with ART18 and low-dose CsA was more effective than high-dose CsA and almost completely suppressed EAU development. ART18 as sole therapy was partially effective, and was better than low dose CsA as sole therapy. Splenocytes of protected animals did not transfer EAU to secondary recipients, while splenocytes of sham-treated controls did, suggesting that the number of uveitogenic lymphocytes in the treated host was reduced by the therapy. In contrast, this therapy was completely ineffective against EAU induced by active immunization. The possible reasons for this discrepancy between the two respective models of EAU are discussed.

Animals↗
PubMed1991

Human monocytes in a long-term culture with interleukin-2 show high tumoricidal activity against various tumor cells.

We compared the tumoricidal activity of human monocytes cultured with interleukin-2 (IL-2) or human recombinant interferon-gamma (IFN-gamma) alone, or IFN-gamma in combination with a small amount of lipopolysaccharides (LPS). Human monocytes cultured with IL-2 for 7 days or longer, termed lymphokine-activated macrophages (LAMs), showed higher tumoricidal activity than those cultured for 1 day. In contrast, monocytes cultured with IFN-gamma alone or in combination with LPS for 7 days or longer showed lower tumoricidal activity. LAMs were identified as macrophages by nonspecific esterase staining and immunofluorescence staining with anti-CD14 antibody. LAMs were not induced in fetal calf serum-containing medium, but they were induced when colony-stimulating factor-1 was added to the medium. LAMs showed high tumoricidal activity against all human and murine tumor cell lines tested, although they showed no cytotoxic activity against human normal cells. During incubation with IL-2, tumoricidal activity of LAMs was maximal at days 8-16 and was sustained until day 28. The difference in tumoricidal mechanism between LAMs and lymphokine-activated killer (LAK) cells was also shown by using two kinds of cytotoxic assay systems. LAMs require a long incubation time to kill tumor cells, but LAK cells can kill them immediately. Furthermore, LAMs kill tumor cells with complete DNA degradation, whereas LAK cells can induce significant but not complete DNA degradation. These results indicate that LAMs and LAK cells have different tumoricidal mechanisms for killing target cells, although they were induced by incubation with the same lymphokine, IL-2.

Animals↗
PubMed1991

Macrophage migration inhibitory factor (MIF) produced by a human T cell hybridoma clone.

A human T cell hybridoma clone, F5, producing high levels of macrophage migration inhibitory factor (MIF) was established by the emetine-actinomycin D selection method. This clone produced two species of MIF which were separated on a Phenyl Sepharose column. We purified MIF-2 (the more hydrophobic species of the two) to homogeneity from the conditioned medium of stimulated F5 cells by a series of steps that included hydrophobic chromatography, ion-exchange chromatography. Ricinus communis lectin affinity chromatography, and high-performance liquid chromatography on anion exchange and reverse-phase columns. Purified MIF was digested with endoproteinase Lys-C and Asp-N. The amino acid sequences of the generated peptides were determined. No sequence similarity with any other protein was found. The molecular weight of MIF-2 was estimated to be 45 kDa from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of immunoprecipitates with anti-peptide antibodies. These results show that F5MIF-2 is a novel cytokine.

Amino Acid Sequence↗
PubMed1991

Plasma lipid and lipoprotein profile in elderly female runners.

Plasma lipid and lipoprotein profiles were compared in elderly female runners (RU: n = 15, aged 66 +/- 5 years, body fat 20 +/- 4%, training distance 35 +/- 15 km week-1, VO2max 36 +/- 4 ml kg-1 min-1, mean +/- SD) and age-matched untrained women (UT: n = 28, 66 +/- 4 years, body fat 26 +/- 6%, VO2max 26 +/- 3 ml kg-1 min-1). There were insignificant differences in total cholesterol (RU: 5.04 +/- 0.60 vs. UT: 5.48 +/- 0.85 mmol l-1), HDL-cholesterol (RU: 1.97 +/- 0.41 vs. UT: 1.91 +/- 0.36 mmol l-1) and LDL-cholesterol (RU: 2.72 +/- 0.59 vs. UT: 3.03 +/- 0.80 mmol l-1) between the two groups. Plasma triglyceride concentration of the runners was significantly lower than that of the untrained women (RU: 0.80 +/- 0.27 vs UT: 1.14 +/- 0.36 mmol l-1, P less than 0.01). No difference was observed in the LDL-cholesterol/HDL-cholesterol ratio between the two groups (RU: 1.45 +/- 0.51 vs UT: 1.64 +/- 0.53 units). These results suggest that regularly performed running of 35 km week-1 in elderly women does not further elevate their HDL-cholesterol level which is already high compared to the levels found in elderly men. However, elderly female runners appear to be protected against age-related increases in the levels of triglyceride and LDL-cholesterol.

Aged↗
PubMed1991

Relationship between the duration of fetal breathing movements and gestational age and the development of the central nervous system at 25-32 weeks of gestation in normal pregnancy.

In 15 pregnant women with normal pregnancy at 25-32 weeks of gestation, fetal breathing movements (FBM), fetal body movements and fetal heart rate were continuously and simultaneously recorded over a total period of 180 min. The frequency of successive FBM with a duration less than 10 s (apnea period greater than 3 s) showed a significant decrease (p less than 0.01), while the frequency of successive FBM with a duration greater than or equal to 30 s showed a significant increase from 25 to 32 weeks of gestation (p less than 0.001). Strong positive correlations were also demonstrated between the frequency of FBM with a duration of greater than or equal to 30 s and the number of fetal heart rate accelerations per hour, acceleration/fetal body movement ratio, and the value of fetal heart rate long-term variability. These results suggest that the length of the duration of successive FBM represents a useful parameter for the analysis of fetal respiratory patterns, and that a prolongation of the duration of successive FBM of an individual fetus is related to the functional development of the central nervous system.

Central Nervous System↗
PubMed1991

Relationship of fetal breathing movement pattern to surfactant phospholipid levels in amniotic fluid and postnatal respiratory complications.

Fetal breathing patterns in 102 patients delivering before 37 weeks of gestation were divided into three types by the duration of successive respiratory activity using an ultrasonic scanner. Approximately 80% of the fetuses with fetal breathing absent or less than 9 s developed neonatal respiratory complications, including 11 cases of severe RDS and 8 cases of apnea of prematurity. However, no infant showing breathing activity of 30 s or more in utero experienced severe respiratory complications after birth. Furthermore, the surfactant phospholipid concentration in amniotic fluid was significantly increased with prolongation of successive fetal breathing activity. These results suggest that the duration of successive fetal breathing movements closely relates with fetal lung development including biochemical and neuromuscular systems in the humans, i.e. functional maturation of the fetal respiratory system, and also that prenatal analysis of breathing patterns may permit evaluation of pulmonary functional capacity after birth.

Amniotic Fluid↗
PubMed1991

Ouabain-like Na+,K(+)-ATPase inhibitory activity of a plasma extract in normal pregnancy and pregnancy induced hypertension.

To estimate the participation of a Na+,K(+)-ATPase-inhibiting plasma factor in pregnancy induced hypertension (PIH), the inhibitory activity and the characteristics of plasma extract eluted with ethanol through a C8 column were examined in normotensive non-pregnant women (N) and women with normal pregnancy (NP) and PIH. There were no differences among the 3 groups in the Na+,K(+)-ATPase activity of erythrocyte ghosts. The heat- and acid-stable plasma extract dose-dependently inhibited Na+,K(+)-ATPase activity with a pattern similar to that of ouabain, but different from that of vanadate. The inhibitory activity of plasma extract was not influenced by polyclonal digoxin antibody which almost completely prevented digoxin-induced inhibition and slightly but significantly reduced the ouabain-induced one. The results indicate that the plasma extract has ouabain-like inhibitory activity on Na+,K(+)-ATPase and that it is not endogenously synthesized digoxin itself, but a substance differing in structure from digoxin. Furthermore, the ouabain-like Na+,K(+)-ATPase inhibitory activity in NP plasma was significantly lower than that in PIH plasma, which was similar to that in N plasma. There were significant relationships between the ouabain-like Na+,K(+)-ATPase inhibitory activities in plasma and the diastolic and systolic blood pressures in NP and PIH groups. The results suggest that the lower ouabain-like Na+,K(+)-ATPase inhibitory activity in plasma probably participates in maintaining the blood pressure within the normal range during pregnancy and its failure may be involved in the genesis of PIH.

Adult↗
PubMed1991

The influence of experimentally produced oligohydramnios on lung growth and pulmonary surfactant content in fetal rabbits.

To study the effect of oligohydramnios on lung growth and biochemical lung development in fetal rabbits, amniotic fluid was drained through a tube inserted into the maternal peritoneal cavity on the 23 day of gestation. Littermate fetuses without an amniotic shunt were used as controls. The fetuses were delivered abdominally on the 28 day of gestation. In a total of 8 pregnant does, 17 fetuses underwent amniotic shunting and 22 fetuses were used as controls. The amniotic shunt produced a significant reduction in the amniotic fluid volume. There were no differences in the wet weights of the fetal body, liver or brain between the two groups. However, the amniotic shunt significantly decreased the wet weight of the fetal lung, fetal lung wet weight/body weight ratio, and protein concentration per lung as compared to the control fetuses. In the fetal liver and brain tissues, no changes were found in the concentrations of total phospholipids, phosphatidylcholine (PC) or disaturated phosphatidylcholine (DSPC, the main component of lung surfactant) per g of wet tissue and per mg of protein. However, the lungs of the fetuses with amniotic shunts contained significantly more PC and DSPC, and the L/S ratio was higher than in the control fetuses. These results suggest that the oligohydramnios produced by an amniotic shunt causes pulmonary hypoplasia, but raises the pulmonary surfactant content of fetal rabbit lung.

Animals↗
PubMed1991

[Immunohistochemical localization of fibronectin, laminin and fibronectin-receptor in human malignant gliomas--in relation to tumor invasion].

In order to examine a role of extracellular matrix (ECM) components in the process of glioma cell invasion, we investigated the immunohistochemical localization of fibronectin (FN), laminin(LN) and FN-receptor (FN-R) in human malignant gliomas. The surgical specimens were obtained from 15 patients with malignant gliomas. Tumor tissue and adjacent brain tissue including tumor infiltration were frozen at -80 degree C immediately after the resection. Ten microns thick frozen tissue was cut out on a cryostat and divided into three different parts on the histology stained with HE, ie, the tumor region(T), brain tissues with tumor infiltration(I), and the border region between these two parts(B). These sections were air-dried, and fixed with cold acetone (-4 degrees C) for 5min. Adjacent sections were immunohistochemically stained by ABC method, using monoclonal antibody for FN-R and polyclonal antibodies for FN and LN. FN, LN and FN-R were all stained at the vascular and pial-glial basement membranes intensely in all gliomas. In immunostain for FN, fine networks of FN were observed in the extracellular space in all three parts. Some tumor cells were clustered around such networks of FN in brain tissues with tumor infiltration. Immunostain for LN demonstrated that the vascularity in the border between the tumor and the brain with tumor infiltration was much higher than that in other parts. LN was not stained in the extracellular space in all these gliomas. FN-R was expressed in some tumor cells, especially in the clustered tumor cells in the brain with tumor infiltration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Macrophage migration inhibitory factor (MIF) produced by a human T cell hybridoma clone.

A macrophage migration inhibitory factor (MIF) was purified to homogeneity from the serum-free culture supernatant of a human T cell hybridoma clone called F5. This clone was established by means of somatic fusion, using the emetine-actinomycin D selection method, and produced a large amount of MIF. The MIF activity in the culture supernatant of F5 cells was not due to contaminating interferon-gamma (IFN-gamma), which is known to possess MIF activity. Furthermore, other known cytokines, such as tumor necrosis factor (TNF), interleukin-1 (IL-1), and granulocyte-macrophage colony-stimulating factor (GM-CSF), were also revealed to have MIF activity, but our MIF was different from these known factors. F5 cells produced two species of MIF that could be separated on a phenyl-Sepharose column. MIF-1 (the more hydrophilic species of the two) was purified to homogeneity by sequential hydrophobic chromatography, ion-exchange chromatography, dye ligand affinity chromatography, and high-performance liquid chromatography (HPLC) on ion-exchange and reverse-phase columns. Finally, 4600-fold enrichment, as to specific activity, of MIF-1 was achieved. The purified MIF-1 was digested with endoproteinase Lys-C into some peptide fragments and the amino acid sequences of the peptides obtained were determined. No sequence identity between our MIF-1 and other proteins was observed. Then, antibodies were raised against a peptide synthesized according to the determined amino acid sequence. They specifically reacted with MIF-1 and reduced its migration inhibitory activity. Based on these results, we conclude that the determined amino acid sequence was certainly that of MIF-1.

Amino Acid Sequence↗