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Biomedical subjects

M Kishi

Publications and source records attributed to M Kishi.

At least 19 recordsLinked to original sources
PubMed1992

Association of functional alteration in intracellular signal transduction systems with the occurrence of up-regulation of muscarinic receptors in primary cultured neurons.

1. Alterations in intracellular biosignaling systems associated with the up-regulated muscarinic receptor were investigated using primary cultured neurons exposured to 10 nM atropine for 5 days. 2. In neurons treated with atropine, the response of PI turnover to muscarinic stimulation decreased in comparison with that in non-treated neurons. 3. The GTP gamma S-stimulated PI turnover also reduced in neurons possessing up-regulated muscarinic receptor, although phospholipase C activity was not different in these two types of neurons. 4. In addition, the long-term exposure (5 days) to atropine induced the increase in GTPase activity and [3H]GppNHp binding. 5. These results suggest that the decreased response of PI turnover to muscarinic stimulation may be attributed to the functional deterioration of G-protein itself and/or coupling between G-protein and phospholipase C. 6. The present results also strongly suggest that the accentuation of the function of G protein may occur in association with the up-regulation of muscarinic receptor.

Animals↗
PubMed1992

Cells surviving infection by human immunodeficiency virus type 1: vif or vpu mutants produce non-infectious or markedly less cytopathic viruses.

Under conditions in which a clonal cell line (M10) isolated from a human T cell lymphotrophic virus type I-transformed MT-4 cell line was completely killed by infection with wild-type human immunodeficiency virus type 1 (HIV-1), equivalent M10 cells survived infection with HIV-1 vif, vpr or vpu mutant virus after transient cytopathic effects. Several cell clones, which were isolated from the proliferating M10 cells after infection with vif and vpu mutant viruses (M10/vif- and M10/vpu-), had heterogeneous HIV-1 phenotypes in terms of HIV-1 antigen expression, their syncytium forming capacity, reverse transcriptase activity and the infectivity of HIV-1 particles produced. When the replication kinetics of the HIV-1 particles produced were assayed in M10 cells, the clones could be classified into three types, i.e. type I producing non-infectious HIV-1, type II producing infectious HIV-1 with low replicative ability and type III producing infectious HIV-1 with a replicative ability similar to that of wild-type HIV-1. HIV-1 major viral cell proteins and virus particle fractions were almost typical in types II and III but not in type I. Electron microscopic examination of particles released by I, II and III clones revealed rare defective, predominantly defective and essentially normal virions, respectively. Northern and Southern blot analyses revealed no apparent deletion in the proviral DNA and mRNA prepared from these clones, except in the case of type I and II clones isolated from M10/vpu- which contained large deletions in the mRNAs for gag and gag-pol proteins. Thus, M10 cells surviving infection with HIV-1 vif or vpu mutants are heterogeneous, persistently expressing HIV-1 antigens and producing non-infectious or less cytopathic virus.

Blotting, Northern↗
PubMed1992

Human immunodeficiency virus type 1 (HIV-1) superinfection of a cell clone converting it from production of defective to infectious HIV-1 is mediated predominantly by CD4 regions other than the major binding site for HIV-1 glycoproteins.

A cell clone, L-2, which produces non-infectious doughnut-shaped human immunodeficiency virus type 1 (HIV-1) particles, was permissive for HIV-1 superinfection, which resulted in the production of infectious particles. The superinfection showed slow kinetics compared with primary HIV-1 infection of M10 cells, the parent of the L-2 cell clone. Inhibition studies on the superinfection of L-2 cells using several CD4-related reagents showed that the CD4 molecule was an essential component of the receptor for superinfection. Strong inhibitory effects were obtained using CD4 peptides such as CD4(68-130), which includes a portion homologous to the immunoglobulin third complementarity-determining region (CDR3), as well as recombinant soluble CD4. In contrast, a CD4(45-60) peptide, which includes most of the CDR2-related region, was not effective, although the Leu-3a monoclonal antibody (MAb), which recognizes a site near the CDR2-related region, did slightly, but significantly, delay the superinfection kinetics. Comparative flow cytometry of L-2 and M10 cells revealed that the cell surface of L-2 cells despite expressing HIV-1 env protein, reacted slightly with OKT4 or anti-CD4(68-130) MAb, but not with Leu-3a or OKT4A MAb. In contrast, no reaction was detected with any of these anti-CD4 MAbs on the surface of another HIV-1 superinfection-resistant cell clone, MOLT-#8IIIB-14, which expresses HIV-1 env proteins but does not produce infectious HIV-1 particles. These results strongly suggest that expression of the CD4 major receptor site for primary HIV-1 infection is preferentially decreased on the surface of L-2 cells, but that the OKT4 epitope and the nearby region corresponding to immunoglobulin CDR3 remain exposed on the cell surface. Consequently, the CD4 CDR3-related region could play a major role as the receptor for the superinfection reported here.

Binding Sites↗
PubMed1992

[Experimental urinary tract infection caused by Escherichia coli in diabetic mouse--uroepithelial colonization and polymorphonuclear leukocyte function].

Relationship between polymorphonuclear leukocyte (PMN) function and susceptibility to infections in diabetic mice was studied. In the experimental urinary tract infections, 6 strains of Escherichia coli with different fimbrial expression and hemolysin production were used. In contrast with non-fimbriated strains, fimbriated strains were more susceptible to phagocytosis by PMN. MS+.MR+ strains, however, showed resistance to intracellular killing by PMN. OEC-709, OEC-716 (MS+.MR+ strains), and OEC-734 (MS+.MR- strains), also showed resistance to the bactericidal activity of the serum. The killing activities of PMN derived from diabetic mice against these 3 strains were significantly lower than those of PMN from normal mice. In normal mice, MS+.MR+ strains showed the strongest colonization ability to the bladder and kidney, whereas MS-.MR- strains showed the weakest ability among the strains. In diabetic mice, the number of bacteria colonizing to the bladder and kidney was higher than that in normal mice, except for one MS-.MR- strain. Significant differences were observed in the strains (OEC-709, 716, 734), in which PMN was concerned strongly in the bacterial killing. Finally, these findings suggest that deterioration of the bactericidal activity of PMN in a diabetic state is involved in increased susceptibility of diabetic mice.

Animals↗
PubMed1991

Human immunodeficiency virus type 1 vif, vpr, and vpu mutants can produce persistently infected cells.

A series of human immunodeficiency virus type 1 (HIV-1) mutants in vif, vpr, vpu, and nef were constructed from an infectious plasmid (pNL 432) containing the full-length HIV-1 DNA by frameshift mutations. The capacities for replication and cell killing of these mutant viruses were examined in a clonal cell line (M 10) isolated from HTLV-I-transformed MT-4 cells. In all cases, the mutant viruses replicated, expressed HIV-1 antigens, and induced drastic cytopathic effects. However, some M 10 cells survived infection with vif, vpr, and vpu mutant viruses and became persistently HIV-1-infected, whereas no cells survived infection with the nef mutant as well as the wild-type virus. The HIV-1 particles produced from the surviving cells after infection with the vif, vpr, or vpu mutant viruses were fully replicative in M 10 cells without apparent cytopathic effects.

Cell Death↗
PubMed1991

Ontogeny of beta-adrenergic receptor-mediated cyclic AMP generating system in primary cultured neurons.

The developmental changes in the beta-adrenergic receptor/cyclic AMP generating system were examined using mouse cerebral cortical neurons in primary culture. During neuronal growth in vitro, the number of binding sites for [3H]dihydroalprenolol (DHA) showed a tendency to increase (Bmax), while the affinity (Kd) for [3H]DHA did not show any noticeable changes. Basal and isoproterenol-stimulated adenylate cyclase activities as well as the activation of adenylate cyclase by 5'-guanylylimidodiphosphate (GppNHp), NaF and forskolin showed progressive and parallel increases during neuronal growth on a polylysine-coated surface. The treatment of primary cultured neurons with islet-activating protein (IAP), one of the pertussis toxins, attenuated the inhibitory effect of carbachol, a muscarinic agonist, on isoproterenol-induced activation of adenylate cyclase activity. These results indicate that primary cultured neurons possess a cyclic AMP generating system coupled with beta-adrenergic and muscarinic receptors, which is regulated via stimulatory and inhibitory GTP-binding proteins, respectively. The results described above also suggest that the beta-adrenergic receptor, stimulatory and inhibitory types of GTP-binding proteins and adenylate cyclase may develop in a parallel fashion during neuronal growth on a polylysine-coated surface.

Adenylate Cyclase Toxin↗
PubMed1991

Inverted repeat regions of Marek's disease virus DNA possess a structure similar to that of the a sequence of herpes simplex virus DNA and contain host cell telomere sequences.

The genomic structure of Marek's disease virus (MDV) is similar to those of the alphaherpesviruses herpes simplex virus (HSV) types 1 and 2. Sequence analysis of the junction region between the long component (L) and the short component (S) revealed the existence of an a-like sequence, similar in structure to the a sequence of HSV-1. Further study revealed that the MDV genome contains five copies of the a-like sequence within the long terminal repeat region as well as in the short terminal repeat region. The junction between the L and S components was found to contain 10 copies of the a-like sequence. Within the a-like sequence, a structure homologous to the DR2 of HSV was found to contain 17 copies of the telomeric sequence, GGGGTTA. There appears to be little to no sequence homology between the HSV a sequence and the MDV a-like sequence; however, the strong physical homology to its counterpart in HSV-1 suggests that the MDV a-like sequence may have the same functional homology (the domain for cleavage/packaging of the DNA into the viral capsids and for genomic inversion) as well.

Animals↗
PubMed1991

Pharmacological characteristics of choline transport system in mouse cerebral cortical neurons in primary culture.

The characteristics of [3H]choline transport with high affinity were investigated using primary cultured neurons obtained from the mouse cerebral cortex. [3H]Choline uptake was saturable as a function of extracellular [3H]choline concentration. Analysis by Lineweaver-Burk plot revealed that [3H]choline was transported into neurons by a high affinity transport system with a Km value of 19.8 +/- 0.8 microM and Vmax value of 0.334 +/- 0.022 nmol/mg protein/min. This high affinity transport of [3H]choline was significantly inhibited by the withdrawal of sodium from the incubation medium, incubation at low temperature (4 degrees C) and addition of metabolic inhibitors such as monoiodoacetate. These results indicate that the high affinity [3H]choline uptake in primary cultured neurons is sodium- and energy-dependent. Hemicholinium-3 also showed a competitive inhibition on the [3H]choline transport. Depolarization by high K+ induced an enhancement of the [3H]choline uptake in the presence of Ca2+. The crude synaptosomal fraction obtained from primary cultured neurons possessed approximately forty-fold higher synthesizing activity of [3H]acetylcholine from [3H]choline than that found in the homogenate preparation of cultured neurons. The present results strongly suggest that the primary cultured neurons used in this study possess a sodium- and energy-dependent high-affinity choline uptake system as well as a synthesizing system for acetylcholine. Possible usefulness of these neurons for investigating neuronal uptake of choline and its functional role in the biosynthesis of acetylcholine are also suggested.

Acetylcholine↗
PubMed1991

[Effect of careful tooth-brushing instruction by teachers on incipient gingivitis in school children].

At the Hiraizumi Primary School in Iwate Prefecture, 84 children with incipient gingivitis were selected at the annual dental examination in May. And the teachers instructed these children individually how to remove the remaining dental plaque. Moreover, the children were checked for the cleanliness of the teeth and inflammation of the gingiva by the teacher or their parents three times a day during the one week just before the second examination. In July the second examination was held and it was revealed that in sixty-three of eighty-four selected children the incipient inflammation of gingiva had improved.

Age Factors↗
PubMed1991

[A five-year follow-up study on blood pressure and serum cholesterol in junior high school children].

Blood pressure and serum cholesterol changes over a five-year period were studied in 299 junior high school children (127 males and 172 females) examined during 1980-1984 in Akita Prefecture, Japan. The six factors studied were height, weight, body mass index (by Minowa's method), systolic blood pressure, diastolic blood pressure and serum cholesterol. Mean values for systolic and diastolic blood pressure increased more than 10 mmHg during the five years in both sexes. Significant positive correlations between initial and follow-up blood pressure ('tracking') were observed. The correlation coefficients for systolic blood pressure in males and in females were 0.33 and 0.28 respectively, and those for diastolic blood pressure were 0.36 in males and 0.19 in females. While there were no significant differences in serum cholesterol levels between the two periods in either sex, the correlation coefficients, which were higher than those for blood pressure, were 0.55 in males and 0.45 in females. Among the six factors at each period, significant positive correlations were observed between height and systolic blood pressure at the initial period, and between obesity and systolic blood pressure at both periods in males and females. A significant positive relationship between obesity and serum cholesterol was seen at the follow-up period in both sexes. These data suggest that a moderate degree of 'tracking' occurs in blood pressure and serum cholesterol during childhood, and that obesity is an important factor related to blood pressure and serum cholesterol.

Adolescent↗
PubMed1990

Alterations in receptor-coupled second messenger systems at up-regulated muscarinic receptors: analysis using primary cultured neurons.

The effect of a long-term exposure (5 days) to atropine on muscarinic acetylcholine receptors and receptor-coupled second messenger systems was investigated using mouse cerebral cortical neurons in primary culture. The long-term exposure of neurons to atropine (10 nM) induced increases in both the Bmax and Kd values of [3H]quinuclidinyl benzilate (QNB) binding to muscarinic acetylcholine receptors. Alterations in muscarinic receptor-coupled second messenger systems, such as phosphoinositide (PI) hydrolysis and cyclic GMP (cGMP) formation following a long-term exposure to atropine, were also examined. Carbachol-stimulated PI hydrolysis was found to be decreased by the exposure to atropine in spite of the increase of muscarinic receptors. In addition, a long-term exposure to atropine had no effect on carbachol-stimulated cGMP formation as well as on the rightward shift of the carbachol competition curve of [3H]QNB binding in the presence of GTP. These results suggest that the up-regulation in muscarinic cholinergic receptors induced by long-term exposure to atropine may involve not only the increase in number of muscarinic receptors but also the decreased responsiveness in muscarinic receptor-coupled second messenger systems.

Animals↗
PubMed1990

Phorbol ester-induced expression of the common, low-affinity binding site for primary prostanoids in vascular smooth muscle cells.

We showed in an earlier study (Hanasaki, K., and Arita, H. (1989) Biochim. Biophys. Acta 1013, 28-35) that there is a common, low-affinity binding site for primary prostanoids in cultured vascular smooth muscle cells (VSMC). This site, called the "primary prostaglandin (PG) site," can be evaluated by radioreceptor assay using [3H]PGF2 alpha and [3H]PGE1. Comparison of the capacity of several PGF2 alpha analogs to displace both radioligand bindings indicated strict requirements of the 15-hydroxy group as well as the 13,14-double bond in the omega-side chain of prostaglandins for recognition of this site. Treatment of VSMC with phorbol 12-myristate 13-acetate (PMA), a known protein kinase C activator, led to concentration- and time-dependent increases in the binding activities of [3H] PGF2 alpha as well as [3H]PGE1, which could be completely suppressed by the addition of protein kinase C inhibitor, H-7. The PMA effects could be mimicked by phorbol 12,13-dibutylate, but not by inactive phorbol ester. Scatchard analyses revealed an approximately 8-fold increase in the binding density with unaltered binding affinity after PMA treatment. This expression of the primary PG site was blocked by the addition of cycloheximide and actinomycin D. In contrast, PMA did not affect the binding activity for the thromboxane A2/prostaglandin H2 receptor in VSMC. These results suggest that the expression of the primary PG site is regulated by a protein kinase C-dependent mechanism in VSMC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Electrical myotonia and cataract in X-linked muscular dystrophy (mdx) mouse.

An X chromosome-linked mouse mutant (mdx) has been investigated as an animal model of Duchenne's muscular dystrophy, and has been found to have the same defect of dystrophin in the muscle surface membrane. Intracellular recordings from the mdx mouse hemidiaphragm preparations revealed low resting membrane potentials and electrical myotonia which occurred at the time of microelectrode insertion and withdrawal. Electrical myotonia of the mdx mouse was observed in 30-50% of the impaled muscle fibers at low temperature, which decreased to only 7.8% at 37 degrees C. Electrical myotonia of mdx mice was not abolished by (+)-tubocurarine. Though there was no behavioral myotonia in mdx mice, repetitive bursts of action potentials in mdx mice were based on the abnormalities of the muscle membrane since neuromuscular blockade did not abolish the repetitive bursts. Also close observation of the lenses of mdx mice revealed cataracts from the newborn stage to the adult age. Slit lamp examination of the lenses of the mdx mice revealed nuclear cataracts followed by anterior subcapsular cataract as they grew. The cataract of mdx mice is different from that of myotonic dystrophy which is usually posterior subcapsular.

Animals↗
PubMed1990

A case of bilateral ptosis associated with cerebral hemispheric lesions.

Ptosis occurs in a variety of disorders including myasthenia gravis, oculomotor palsy, Horner's syndrome and brain stem disorders. There are also supranuclear lesions causing blepharoptosis. The latter disorders are reflex blepharospasm, apraxia of eyelid opening and Meige's syndrome. Since the total number of bilateral ptosis associated with cerebral hemispheric lesions is very few, whether the responsible lesions are located in the nondominant hemisphere or bilateral hemispheres are still controversial. We report here a case of bilateral cerebral ptosis that occurred in association with cerebral infarction of the nondominant hemisphere.

Aged↗
PubMed1990

The stabilizing effect of bestatin on the resting membrane potentials of X-linked muscular dystrophy mice.

The resting membrane potentials of X-linked muscular dystrophy (mdx) mice are about 10 mV lower than those of control (C57BL/10Sc) mice. Also repetitive action potentials which resemble insertion myotonia are frequently recorded intracellularly from the mdx mice of various ages. When the mdx mice are treated with bestatin intraperitoneally for 7 days, the RMP's improvement almost attained its normal levels. Repetitive action potential bursts (electrical myotonia) recorded at the time of microelectrode insertion had decreased or abolished after bestatin therapy. Another set of in vitro experiments to see direct action of bestatin to the hemidiaphragm preparations of the mdx mice reveal improvement in RMP's and a reduction in electrical myotonia within a 30-minute exposure to Tyrode's solution with bestatin. Bestatin has a favorable direct effect on the muscle fiber membrane to stabilize RMP's and suppress muscle membrane irritability.

Animals↗
PubMed1990

Prognosis and disability of stroke patients after 5 years in Akita, Japan.

The system of registering stroke patients was begun in 1963 in Ikawa Town, Akita Prefecture, Japan. The town is located in the northeastern part of the country and in 1975 had a population of 6,427. From 1975 to 1981, 109 patients who suffered their first stroke were registered and were monitored for 5 years. The average annual incidence rates of stroke were 2.8 and 2.0 per 1,000 population in males and females, respectively. Mean age at stroke onset was 63.3 and 71.4 years in males and females, respectively (p less than 0.01). According to the clinical classification of stroke, 76 patients suffered cerebral infarction, 21 cerebral bleeding, and six subarachnoid hemorrhage; six strokes were unclassified. The survival rates were compared by sex, age, and clinical stroke type using Cox's proportional hazards model. The survival rate of female stroke patients was lower than that of males, but not significantly so. The survival rate of stroke patients greater than or equal to 65 years old was significantly lower (p less than 0.01) than that of younger patients. Moreover, the survival rate of patients with cerebral bleeding was significantly lower (p less than 0.01) than that of patients with cerebral infarction. In the analysis of self-care among the survivors, performance of the activities of daily living in older patients indicated significantly less independence (p less than 0.01) in younger patients. Follow-up of new stroke cases showed that age and clinical stroke type were significantly associated with survival and that age was also related to disability of the survivors.

Activities of Daily Living↗
PubMed1990

Inhibitory effect of di- and tripeptidyl aldehydes on calpains and cathepsins.

Eight different di- and tripeptidyl aldehyde derivatives, each having at its C-terminus an aldehyde analog of L-norleucine, L-methionine, or L-phenylalanine with a preceding L-leucine residue, were synthesized and tested for their inhibitory effects on several serine and cysteine endopeptidases. These compounds showed almost no inhibition of trypsin, and only weak inhibition of alpha-chymotrypsin and cathepsin H, while they exhibited marked inhibition of cathepsin B less than calpain II congruent to calpain I less than cathepsin L, being stronger in this order. The mode of inhibition of these cysteine proteinases was competitive for the peptide substrate used and inhibitor constants (Ki) were calculated from the Dixon plot. The best inhibitors found were: 4-phenyl-butyryl-Leu-Met-H for calpain I (Ki, 36 nM) and calpain II (Ki, 50 nM); acetyl-Leu-Leu-nLeu-H for cathepsin L (Ki, 0.5 nM); acetyl-Leu-Leu-Met-H for cathepsin B (Ki, 100 nM).

Aldehydes↗