Biomedical subjects

M Nishimura

Publications and source records attributed to M Nishimura.

At least 19 recordsLinked to original sources

PubMed1992

C33 antigen recognized by monoclonal antibodies inhibitory to human T cell leukemia virus type 1-induced syncytium formation is a member of a new family of transmembrane proteins including CD9, CD37, CD53, and CD63.

C33 Ag was originally identified by mAb inhibitory to syncytium formation induced by human T cell leukemia virus type 1. The Ag was shown to be a highly heterogeneous glycoprotein consisting of a 28-kDa protein and N-linked oligosaccharides ranging from 10 to 50 kDa. In the present study, cDNA clones were isolated from a human T cell cDNA expression library in Escherichia coli by using mAb C33. The identity of cDNA was verified by immunostaining and immunoprecipitation of transfected NIH3T3 cells with mAb. The cDNA contained an open reading frame of a 267-amino acid sequence which was a type III integral membrane protein of 29.6 kDa with four putative transmembrane domains and three putative N-glycosylation sites. The C33 gene was found to belong to a newly defined family of genes for membrane proteins, such as CD9, CD37, CD53, CD63, and TAPA-1, and was identical to R2, a cDNA recently isolated because of its strong up-regulation after T cell activation. Availability of mAb for C33 Ag enabled us to define its distribution in human leukocytes. C33 Ag was expressed in CD4+ T cells, CD19+ B cells, CD14+ monocytes, and CD16+ granulocytes. Its expression was low in CD8+ T cells and mostly negative in CD16+ NK cells. PHA stimulation enhanced the expression of C33 Ag in CD4+ T cells by about 5-fold and in CD8+ T cells by about 20-fold. PHA stimulation also induced the dramatic size changes in the N-linked sugars previously shown to accompany human T cell leukemia virus type 1-induced transformation of CD4+ T cells.

Amino Acid Sequence↗

PubMed1992

Purification, cDNA cloning and Northern-blot analysis of mitochondrial chaperonin 60 from pumpkin cotyledons.

Two different cDNA clones, pMCPN60-1 and pMCPN60-2, encoding the mitochondrial homologues of chaperonin 60 (Cpn60) were isolated from a cDNA library of germinating pumpkin cotyledons by use of mixtures of synthetic oligonucleotides based on the N-terminal amino acid sequence of the protein. Determination of the complete nucleotide sequences of the two cDNA revealed that pMCPN60-1 and pMCPN60-2 each contain one open reading frame that encodes a protein of 575 amino acids with molecular masses of 61052 Da and 61127 Da, respectively. The deduced amino acid sequences of the two polypeptides include a 32-residue N-terminal putative mitochondrial presequence attached to the mature polypeptides, and they are 95.3% identical. From a comparison of deduced amino acid sequences with other Cpn60, it appears that the mature polypeptides of pumpkin mitochondrial Cpn60 are 44-59% identical to the other Cpn60, namely, GroEL of Escherichia coli, the 60-kDa heat-shock protein (Hsp60) of mitochondria in the yeast Saccharomyces cerevisiae, P1 protein of mammalian mitochondria and the Ribulose-1,5-bisphosphate carboxylase/oxygenase subunit-binding proteins alpha and beta of plastids in higher plants. Genomic Southern-blot analysis identified at least two copies of the gene for mitochondrial Cpn60 in the pumpkin genome. The levels of mRNA for mitochondrial Cpn60 in cotyledons, hooks and hypocotyls of pumpkin seedlings increased in response to heat stress, as deduced from Northern-blot analysis, indicating that pumpkin mitochondrial Cpn60 is a heat-induced stress protein.

Amino Acid Sequence↗

PubMed1992

Glial fibrillary tangles with straight tubules in the brains of patients with progressive supranuclear palsy.

A recent report has described the appearance of silver positive, tau-immunoreactive astrocytes in the brains of patients with progressive supranuclear palsy (PSP) (Neurosci. Lett., 135 (1992) 99-102). In this study we confirmed this finding in two cases of PSP by using Bodian silver staining and immunohistochemistry with antibody to human tau protein. By electron microscopy we demonstrated that fibrillary masses present in these unique astrocytes were made up of straight tubules that were indistinguishable from those of neurofibrillary tangles of PSP. The term 'glial fibrillary tangle' was proposed for these structures.

Aged↗

PubMed1992

Stimulation of phosphoinositol turnover and protein kinase C activation by granulocyte-macrophage colony-stimulating factor in HL-60 cells.

Phosphoinositol turnover, diacylglycerol generation, protein kinase C (PK-C) activity, and intracellular cyclic nucleotides were studied in an established human leukemia cell line, HL-60, in response to one of the hematopoietic cytokines, granulocyte-macrophage colony-stimulating factor (GM-CSF). Continuous exposure of HL-60 cells to GM-CSF induced the cell differentiation that was evaluated by the nitroblue tetrazolium (NBT) reducing activity. GM-CSF also exhibited a proliferative effect on HL-60 cells. GM-CSF at 1 nmol/L, an optimal concentration for cell growth and cell differentiation, induced significant changes in the intracellular inositoltriphosphate (IP3). Diacylglycerol generation was also stimulated by GM-CSF treatment. GM-CSF increased the membrane PK-C activity by 10-fold of the control, whereas no measurable change in cyclic nucleotides was observed. These data indicated that phosphoinositol turnover and the activation of PK-C were included in the GM-CSF signal transducing pathway in HL-60 cell. Phosphoinositol response leading to PK-C activation may act as a trigger signal of cell differentiation by GM-CSF.

Cell Differentiation↗

PubMed1992

Diversity among mouse motor nerve terminals with respect to release transmitter quanta.

1. The aim of this work was to reexamine whether a positive correlation exists between the frequency (F, sec-1) of miniature endplate potentials (m.e.p.ps) and the quantal content (m) of endplate potentials (e.p.ps) or between quantal content, frequency and twin-pulse facilitation of transmitter release at a large number of neuromuscular junctions in the mouse. 2. The values of F and m were both measured intracellularly at endplates of mouse diaphragm in a high Mg2+/low Ca2+ bathing solution. 3. Values of both F and m varied from junction to junction. Smaller values of F were correlated with smaller values of m, and vice versa, resulting in a linear relationships. Histograms of F and m were skewed towards smaller values. 4. E.p.ps evoked by twin pulses gave the quantal contents of the first (m1) and second (m2) responses. 5. The ratio of m2 to m1 varied from junction to junction. A histogram of this ratio was skewed towards smaller values. 6. The ratio of m2 to m1 showed larger fluctuations at junctions with smaller values of F or m1 but was focused around 1 at junctions with larger values of F or m1. 7. The skewed parts of the histograms of F, m and m2/m1 accounted for the major population of junctions. 8. These results support the hypothesis that an intrinsic ability to release transmitter plays a role in regulation of the evoked output of transmitter at neuromuscular junctions in the mouse. 9. Such an ability is not correlated with the twin-pulse facilitation of transmitter release.

Animals↗

PubMed1992

Anti-idiotypic antibody to T-cell receptor in multiply transfused patients may play a role in resistance to graft-versus-host disease.

Most patients who receive multiple blood or platelet transfusions do not develop graft-versus-host disease (GVHD) in spite of the transfusion of donor white cells--cells that are capable of engraftment and subsequent GVHD. The object of this study was to search for the factors responsible for resistance to GVHD in such patients. Some sera from patients who have received multiple platelet transfusions inhibit the proliferation of alloreactive T-cell clones that function as an in vitro model of donor-derived proliferating T cells recognizing recipient alloantigens. The humoral factor in such sera was capable of binding to the T-cell clones, but not to stimulator cells. Further analysis revealed that the humoral factor in such sera was IgG, which specifically bound to membrane molecules of the T-cell clones. The antibody competed with WT31, a monoclonal antibody (MoAb) to T-cell receptor (TCR), in binding to TCR of the T-cell clones. It did not compete with CD3 or CD2 MoAb. These observations strongly favor the view that the antibody against TCR exists in the sera of multiple transfusion recipients. It is suggested that the TCR antibody binds to TCR of the T-cell clones, thus blocking the interaction of the T-cell clone with alloantigens of stimulator cells and resulting in inhibition of the proliferation of T-cell clones. Furthermore, in view of T-cell clone-specific binding of the antibody in sera, it might be concluded that the antibody is anti-idiotypic.

Antibodies, Anti-Idiotypic↗

PubMed1992

Effects of interleukin-1 beta on blood pressure, sympathetic nerve activity, and pituitary endocrine functions in anesthetized rats.

The effects of interleukin-1 beta (IL-1), an endogenous pyrogen, on both the central and peripheral endocrine, sympathetic, and cardiovascular systems were investigated by injecting it intracisternally (IC) and intravenously (IV). Intracisternal injections of IL-1 caused dose-dependent vasopressor responses, which were accompanied by corresponding increases in the abdominal sympathetic discharge. Blood pressure increased gradually, and attained a peak response at 20 to 30 min. Heart rate also increased dose-dependently. Intracerebroventricular pretreatments with indomethacin abolished both the pressor responses and tachycardia. The IV injections similarly elicited vasopressor responses with gradual onset, which were also accompanied by corresponding increases in the abdominal sympathetic firings. However, IL-1 did not constrict the peripheral vasculature in the perfused hindlimb preparation. Both IC and IV injections of IL-1 increased plasma vasopressin and corticotropin dose-dependently after 30 min. These results indicate that IL-1 of both central and peripheral origin may cause vasopressor responses. These may be partly mediated by the release of vasopressor pituitary hormones. The site of action could be a similar region in the central nervous system.

Adrenocorticotropic Hormone↗

PubMed1992

Effects of endothelin-1 and inhibition of nitric oxide production with NG-monomethyl-L-arginine on arterial pressure and regional blood flow in anesthetized rats.

Regional hemodynamic responses to NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthase, were compared with those to endothelin (ET) using tracer microspheres with a reference sample method in anesthetized rats. Intravenous injections of these agents (16 and 160 mmol/kg of L-NMMA and 0.1 or 0.5 nmol/kg of ET-1) dose-dependently increased the blood pressure to the similar level. The cardiac index markedly decreased with ET-1, but was not greatly influenced by L-NMMA. Coronary and cerebral blood flow were not affected by these agents. ET-1 increased the bronchial arterial flow, and markedly decreased the flow in the other organs and tissues examined. L-NMMA almost homogeneously increased the regional vascular resistance to the lesser extent compared to ET-1. Although both ET-1 and nitric oxide are produced in the same cells and exhibit interrelationships, the present results indicate that the regional vascular effects of these agents are different: (a) ET-1 preferentially constricts arteries in all organs and tissues except the lung (where it increases flow) and the heart and brain where it has no wasted effects, leading to reduction in cardiac output, and (b) nitric oxide dilates arteries predominantly in the kidneys, muscle, and white adipose tissues.

Amino Acid Oxidoreductases↗

PubMed1992

Measurements of serum levels of nitrate ions in men and women: implications of endothelium-derived relaxing factor in blood pressure regulation and atherosclerosis.

As endothelium-derived nitric oxide (NO) is a potent vasodilator and degraded into nitric ions, we measured serum levels of nitrate (NO3-) concentrations as an index of endothelium-derived NO, to assess its role in blood pressure regulation. Because serum NO3- levels in men were significantly elevated compared to those in women, data from these two groups were analyzed separately. In men, multiple regression analysis revealed that NO3- significantly correlated with age, systolic blood pressure, body mass index (BMI), and total cholesterol. Blood pressure correlated with age, BMI, and NO3- with multivariate analysis. In women, NO3- significantly correlated with age, systolic blood pressure, and total cholesterol with a simple correlation. With multiple regression analysis, serum NO3- highly correlated with serum levels of triglyceride and total cholesterol and age. The blood pressure correlated with four parameters, i.e., total cholesterol, age, BMI, and NO3-. In summary, serum NO3- levels seem to relate to serum lipids and glucose levels and blood pressure, which strongly suggests that production of endothelium-derived NO is increased in the atherosclerotic process.

Adult↗

PubMed1992

A leptomycin B resistance gene of Schizosaccharomyces pombe encodes a protein similar to the mammalian P-glycoproteins.

Screening for leptomycin B (LMB)-resistant transformants in a gene library constructed in Schizosaccharomyces pombe with the chromosomal DNA of an LMB-resistant mutant of S. pombe and with multicopy plasmid pDB248' as the vector led to the isolation of a gene, named pmd1+, encoding a 1362-amino-acid protein. This protein showed great similarity in amino acid sequence to the mammalian P-glycoprotein encoded by the multidrug resistance gene, mdr, and the Saccharomyces cerevisiae a-factor transporter encoded by STE6. In addition, computer analyses predicted that the protein encoded by pmd1+ formed an intramolecular duplicated structure and each of the halves contained six transmembrane regions as well as two ATP-binding domains, as observed with the P-glycoproteins and the STE6 product. Consistent with this was that S. pombe cells containing the pmd1+ gene on a multicopy plasmid showed resistance not only to LMB but also to several cytotoxic agents. The pmd1 null mutants derived by gene disruption were viable and hypersensitive to these agents. All these data suggest that the pmd1+ gene encodes a protein that is a structural and functional counterpart of mammalian mdr proteins.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Blockade of Na+ current by promethazine in guinea-pig ventricular myocytes.

1. To elucidate the antiarrhythmic mechanism of promethazine, its effects on the fast Na+ current (INa) were examined in single guinea-pig ventricular myocytes by whole-cell voltage clamp methods. 2. Promethazine blocked INa with a KD of 42.6 microM and Hill's coefficient of 1.1 at a holding potential of -140 mV. 3. The INa blockade was enhanced at a less negative holding potential of -80 mV with a change of KD to 4.4 microM. Although 10 microM promethazine did not change the inactivation time constants of INa, it shifted the steady-state inactivation curve (h infinity curve) toward more negative potentials by 19.5 mV with the slope factor unaffected. 4. Double pulse experiments revealed that the development of blockade followed two-exponential functions having time constants of 7 and 220 ms at -20 mV. 5. Promethazine slowed the repriming of INa. This was associated with the development of slow phase having a time constant of 1160 +/- 59 ms. 6. Promethazine produced a profound use-dependent block when the cell was repeatedly stimulated with interpulse intervals shorter than 1 s. However, short pulses of 2 ms duration hardly produced such a use-dependent block. Hence, open channel blockade is considered to play a minor role in the promethazine action on INa. 7. These results suggest that promethazine blocks cardiac INa in a manner similar to class I antiarrhythmic drugs and that this effect may account for its antiarrhythmic action.

Algorithms↗

PubMed1992

[A clinical study on postantibiotic effect (PAE) and its application to chemotherapy for complicated cystitis with an automatic simulator of urinary drug concentration].

In an in vitro complicated cystitis model, the concentrations of the urinary antimicrobial agents were determined using a computer-controlled automatic urine concentration simulator. The effects on the bacterial count curves showing the presence or absence of PAE in antimicrobial agents were studied by comparing the times required for regrowth to the concentration at the initial inoculation, i.e., effective regrowth time (ERT). The following results were obtained. 1. When beta-lactam antimicrobial agents (such as AMPC and CFIX) with no PAE against the gram-negative rods were tested, the ERT of the gram-negative rods were about two hours shorter than that of the gram-positive coccus. 2. When new quinolone antimicrobial agents (such as OFLX) and aminoglycosides (such as ISP) that possess PAE against both the gram-positive and negative organisms were used there was no difference between ERT of the gram-negative rods and gram-positive coccus. Therefore, it was demonstrated that the presence or absence of PAE is also reflected in the cell number curve in the case of this in vitro model, more closely related to clinical cases, when the antibiotics is simulated in urinary concentration shifting.

Amoxicillin↗

PubMed1992

[Clinical efficacy of levofloxacin (LVFX) single-dose therapy in female acute uncomplicated cystitis].

Treatment of infections by the use of antimicrobial agents should be made essentially in a dose close to the minimally required dose. Acute uncomplicated cystitis in female fits as the subject for a single-dose therapy since it is an infection reactive relatively easily to antimicrobial agents. Accordingly, an assessment has been made regarding the therapeutic results of the single-dose therapy in 76 female cases of acute uncomplicated cystitis by the use of LVFX 200 mg which is a new quinolone. The urinary concentration more than MIC90 to Escherichia coli is sustained for about 3 days by this single-dose therapy. As a result of judging the therapeutic results from the reactions of the three clinical findings of pain on micturition, pyuria and bacteriuria, excellent therapeutic results were obtained with effective rates being 100% (76/76) on the day 3, 93.9% (46/49) on the day 7 and 94.4% (34/36) on the day 14. The rate of cystitic symptoms which recurred posed no problem, being 12.5% (5/40) up to three months, as investigated by a questionnaire. As a result of performing close urological examinations such as cystoscopy on six cases with insufficient results or recurrence, we could detect mild underlying conditions which are considered to be intractable factors in the bladder in three cases. From the above results, the single-dose therapy of acute uncomplicated cystitis in the female by LVFX which is a new quinolone was considered to be an excellent therapeutic drug from its characteristics such as its therapeutic results being the same as the conventional therapy by daily administration, excellent drug compliance, low cost, hard selectiveness of resistant strains, less side effects and furthermore it gives the opportunity of detecting a latent and mild underlying condition.

Acute Disease↗

PubMed1992

[Significance of the combined treatment with isepamicin and piperacillin in an in vitro model for complicated cystitis operated by automatic simulator apparatus for urinary concentration].

Isepamicin (ISP) and piperacillin (PIPC) were shifted to the urinary concentration by employing an in vitro complicated cystitis model operated by a computer-controlled automatic simulator for urinary concentration, and administrated to bacteria in the urinary bladder model (Pseudomonas aeruginosa: P. aeruginosa, initial cell concentration: 10(7) cfu/ml). In this case, effects by single treatment with ISP or PIPC on cell number curves were examined. Further, significance of the combined treatment with ISP and PIPC were investigated by changing the order of each treatment. And following the results were obtained. 1. In a single treatment with PIPC the cell concentration was minimum (10(4) cfu/ml) at 9th hour after its treatment and thereafter, regrowth to the same level as the initial concentration was observed at 16th hour. 2. In the case of single treatment with ISP, the cell concentration became minimum (10(2) cfu/ml) at 13th hour after the treatment and raised to the same concentration as the initial one at 25th hour. 3. In the combined treatment, the cell concentration was minimum (less than 10(1) cfu/ml) at 26th hour in the case of prior treatment with ISP. Thereafter, regrowth was observed and the cell concentration at 42nd hour reached to the initial cell concentration. 4. In simultaneous treatment with ISP and PIPC, the cell concentration at 24th hour was minimum (10(1) cfu/ml) and reached to the same level as the initial one after regrowth. From these results, it was found that the combined treatment with ISP and PIPC caused more reduction of the cell concentration than either single treatment. Further, regrowth of the cells was suppressed for longer duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Simulation↗

PubMed1992

[Epidemiological and bacteriological study on gonococcal infections].

Epidemiological and bacteriological studies on Neisseria gonorrhoeae isolated in Sapporo, Japan, in 1980 and 1991 performed and the following results were obtained. 1. The range of age in the patients infected with Neisseria gonorrhoeae tended to be younger than those in the whole country. 2. Male patients in the early 20s or younger with gonococcal urethritis were often infected by bon-professional females but those in their late 20s or older were often infected from professional females, for example prostitutes and hostesses. 3. The rate of professional females who were positive to gonococci reached 17.4% and young females in their teens with cervicitis had the highest morbidity rate of gonococci than those in the older females. 4. The latent period in gonococcal infections tended to become longer gradually. 5. The isolation rate of penicillinase producing Neisseria gonorrhoeae (PPNG) showed a peak of 23.9% (61/255) in 1985, but gradually declined thereafter and it was 3.7% (1/27) in 1991. 6. An investigation on auxotype showed a decline of proto and Pro-strains and an increase of AHU-strains in non-PPNG. And most of the PPNG belonged to proto or Pro-strains. 7. With the relationship between auxotype and sensitivity to AMPC, AHU-strains were more sensitive than proto or Pro-strains.

Adolescent↗

PubMed1992

Beta-3 adrenergic agonist, BRL-26830A, and alpha/beta blocker, arotinolol, markedly increase regional blood flow in the brown adipose tissue in anesthetized rats.

Regional vascular effects of some adrenergic agents, focussing on brown adipose tissue (BAT), were investigated using tracer microspheres with a reference sample method in the anesthetized rat. Intravenous injections of 0.5 mg/kg BRL-26830A, a beta 3-adrenergic agonist, increased heart rate, but changes in blood pressure and cardiac output were not significant. The drug decreased blood flow in the brain, the spleen and the kidneys, but markedly increased it in BAT. At 2 mg/kg, arotinolol, an alpha/beta-adrenergic blocker, decreased blood pressure by 20 mmHg and increased cardiac output by 95 ml/min/kg. It slightly but significantly decreased blood flow in the liver and the spleen, but markedly increased the flow in BAT. Acebutolol, a beta 1-adrenergic blocker, decreased blood flow in the liver, the spleen, the pancreas, the kidneys, the adrenals, the skeletal muscle and the skin. Bunazosin, an alpha 1-adrenergic blocker, decreased it in all organs and tissue expect the brain and BAT. The pattern of redistribution of blood flow by arotinolol was very similar to that caused by BRL-26830A. Acebutolol and bunazosin rather decreased the blood flow in the BAT. These results indicate that stimulation of beta 3-adrenergic receptors, in BAT results in vasodilation, and that arotinolol may bind to those beta 3-adrenergic receptors.

Adipose Tissue, Brown↗

PubMed1992

Compensatory changes in silver-stainability of nucleolar organizer regions in mice.

Silver-stainability of nucleolar organizer regions (NORs) that contain genes for ribosomal RNA (rDNA) was investigated using two mouse strains, BALB/cCrSlc and MOA, and their hybrid progeny. The patterns of segregation of the rDNA clusters were analyzed in terms of chromosomal C-banding and by use of a polymorphic probe for the variable region in backcrossed N2 and N3 individuals. The results indicate that the intensity of Ag-NOR staining is stably inherited in most of the rDNA clusters, irrespective of different genetic backgrounds. In some clusters, such as those on chromosome 12 of BALB/cCrSlc, a modulation of the intensity is observed. This modulation seems to be due to compensatory activation via a change in the number of actively transcribed genes. The change from silver-negative to silver-positive staining of the NOR of chromosome 12 of BALB/cCrSlc was correlated with demethylation of the genes.

Animals↗

PubMed1992

Paradoxical bradycardia during exercise and hypoxic exposure. The possible direct effect of hypoxia on sinoatrial node activity in humans.

We describe a patient with pulmonary emphysema who developed paradoxical cardiodeceleration not only during incremental exercise associated with hypoxemia but also during progressive hypoxic challenge. Since coronary angiogram revealed no abnormality, this unique phenomenon seemed to be due to the direct effect of hypoxia on the sinus node activity.

Bradycardia↗