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Biomedical subjects

M Kawakami

Publications and source records attributed to M Kawakami.

At least 361 records · Page 20Linked to original sources
PubMed1990

Microtubule-associated-protein (MAP) kinase activated by nerve growth factor and epidermal growth factor in PC12 cells. Identity with the mitogen-activated MAP kinase of fibroblastic cells.

Treatment of PC12 cells with either nerve growth factor (NGF), a differentiating factor, or epidermal growth factor (EGF), a mitogen, resulted in 7-15-fold activation of a protein kinase activity in cell extracts that phosphorylated microtubule-associated protein (MAP) 2 on serine and threonine residues in vitro. Both the NGF-activated kinase and the EGF-activated kinase could be partially purified by sequential chromatography on DEAE-cellulose, phenyl-Sepharose and hydroxylapatite, and were identical with each other in their chromatographic behavior, apparent molecular mass (approximately 40 kDa) on gel filtration, substrate specificity, and phosphopeptide-mapping pattern of MAP2 phosphorylated by each kinase. Moreover, both kinases were found to be indistinguishable from a mitogen-activated MAP kinase previously described in growth-factor-stimulated or phorbol-ester-stimulated fibroblastic cells, based on the same criteria. Kinase assays in gels after SDS/polyacrylamide gel electrophoresis revealed further that the NGF- or EGF-activated MAP kinase in PC12 cells, as well as the EGF-activated MAP kinase in fibroblastic 3Y1 cells resided in two closely spaced polypeptides with an apparent molecular mass of approximately 40 kDa. In addition, these MAP kinases were inactivated by either acid phosphatase treatment or protein phosphatase 2A treatment. These results indicate that MAP kinase may be activated through phosphorylation by a differentiating factor as well as by a mitogen. MAP kinase activation by EGF was protein kinase C independent; it reached an almost maximal level 1 min after EGF treatment and subsided rapidly within 30-60 min. On the other hand, NGF-induced activation of MAP kinase was partly protein kinase C dependent and continued for at least 2-3 h.

Adrenal Gland Neoplasms↗
PubMed1990

Apolipoprotein E and lipoprotein lipase secreted from human monocyte-derived macrophages modulate very low density lipoprotein uptake.

We investigated the roles of lipoprotein lipase and apolipoprotein E (apoE) secreted from human monocyte-derived macrophages in the uptake of very low density lipoproteins (VLDL). ApoCII-deficient VLDL were isolated from a patient with apoCII deficiency. The lipolytic conversion to higher density and the degradation of the apoCII-deficient VLDL by macrophages were very slight, whereas the addition of apoCII enhanced both their conversion and degradation. This suggests that the lipolysis and subsequent conversion of VLDL to lipoproteins of higher density are essential for the VLDL uptake by macrophages. VLDL incubated with macrophages obtained from subjects with E3/3 phenotype (E3/3-macrophages) showed a 17-fold greater affinity in inhibiting the binding of 2 micrograms/ml 125I-low density lipoprotein (LDL) to fibroblasts than native VLDL, whereas the incubation of VLDL with macrophages obtained from a subject with E2/2 phenotype (E2/2-macrophages) did not cause any increase in their affinity. Furthermore, 3 micrograms/ml 125I-VLDL obtained from a subject with E3/3 phenotype were degraded by E3/3-macrophages to a greater extent than by E2/2-macrophages (2-fold), indicating that VLDL uptake is influenced by the phenotype of apoE secreted by macrophages. From these results, we conclude that both lipolysis by lipoprotein lipase and incorporation of apoE secreted from macrophages alter the affinity of VLDL for the LDL receptors on the cells, resulting in facilitation of their receptor-mediated endocytosis.

Apolipoprotein C-II↗
PubMed1990

Augmentation of LDL receptor activities on lymphocytes by interleukin-2 and anti-CD3 antibody: a flow cytometric analysis.

Dormant lymphocytes are known to show little LDL receptor (LDL-R) activities. The present study was designed to determine whether or not LDL-R activities of lymphocytes from normal subjects were high enough to be measured by flow cytometry after the cells had been stimulated with recombinant interleukin-2 (IL-2) and anti-CD3 monoclonal antibody (mAb). IL-2 or anti-CD3 mAb individually provokes proliferation of lymphocytes in a serum-free medium. Proliferation rate was accelerated when the two reagents were used in combination. Stimulated cells cultured for 5 days expressed more than 85% CD3 positive, less than 0.5% CD14 positive, and less than 1.5% CD20 positive. The LDL-R activities of the cells were examined by the uptake of a fluorescence probe, DiI-labeled LDL (DiI-LDL) and analyzed by flow cytometry. Stimulated cells showed increased uptake of DiI-LDL and 84 +/- 9% were positive, whereas only 3.0 +/- 2.5% of the cells without stimulation were positive (P less than 0.001). Under the same conditions stimulated lymphocytes from a homozygous familial hypercholesterolemia (FH) patient showed little LDL-R activities; 14% of the cells were positive. Displacement assays reveal that the uptake of LDL by these cells is occurring by way of its specific pathway. These data imply the lymphocytes stimulated with the reagents used in the study might be used for detecting defects in LDL-R, perhaps defects in other genomic systems as well.

Antibodies, Monoclonal↗
PubMed1990

Influence of electrical stimulation of the hypothalamus on ovarian steroidogenesis in hypophysectomized and adrenalectomized rats.

The effects of electrical stimulation of the lateral hypothalamic area (LHA), periventricular arcuate nucleus (ARC) and ventromedial hypothalamic nucleus (VMH) on the rates of 14C transfer from 14C-1 acetate into ovarian steroids in ovarian slices of hypophysectomized and adrenalectomized (H-A) rats were investigated. The 14C transfer rates into estrogen and 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P) were decreased by LHA stimulation. The stimulation of the ARC and VMH increased the rates of 14C transfer into estrogen, progesterone and 20 alpha-OH-P. From these results, it might be suggested that these hypothalamic structures were involved in the regulation of ovarian steroidogenesis without participation of the pituitary and adrenal.

20-alpha-Dihydroprogesterone↗
PubMed1990

Influence of dorsal hippocampal stimulation and dorsal fornix lesions on hepatic glucose metabolism in rabbits.

We examined the effects of stimulation of the dorsal hippocampus and lesions of the dorsal fornix on glucose metabolism in liver slices of rabbits. Hippocampal stimulation decreased the 14C transfer rates from 14C-glucose into CO2, ketone bodies, cholesterol ester and free fatty acids, but increased the rates into triglyceride, phospholipids and glycogen. Fornix lesions had various effects on glucose metabolism, and the effects of hippocampal stimulation on glucose metabolism were abolished by fornix lesions. These observations support the hypothesis that the hippocampus is an integral part of the brain regulator system in the hepatic glucose metabolism.

Animals↗
PubMed1990

Influence of microinjection of insulin into the ventromedial hypothalamus on acetate metabolism in rumen epithelium of sheep.

Injections of 50 microU insulin into the ventromedial hypothalamic nuclei (VMH) in intact sheep decreased the rates of 14C transfer from 14C-1-acetate into CO2, glucose, ketone bodies, and increased the rates into triglyceride and phospholipids in rumen epithelium of sheep. Insulin injections into the parietal cortex of intact sheep or into the VMH of sheep with VMH lesions had no effect on the acetate metabolism in rumen epithelium as compared with the control groups which received saline injections into the same brain regions. These results support the view that the VMH serves as an integral part of an insulin-sensitive brain regulatory system in the acetate metabolism of rumen epithelium.

Acetates↗
PubMed1990

Cholesterol-free diet with a high ratio of polyunsaturated to saturated fatty acids in heterozygous familial hypercholesterolemia: significant lowering effect on plasma cholesterol.

We have studied the effect of diet therapy on plasma lipoprotein metabolism in heterozygous familial hypercholesterolemia. Seven patients with a mean plasma cholesterol concentration of 323 +/- 67 mg/dl were hospitalized and kept on a cholesterol-free diet for as long as 11 days without any medication. The content of dietary cholesterol was approximately 1.4 mg a day, and dietary fat, carbohydrate and protein comprised 18.0, 69.2 and 12.8% of calories, respectively. The ratio of polyunsaturated to saturated fatty acids (P/S) was 3.1. At the end of the study period, plasma cholesterol was lowered by 14.2%, from 323 to 277 mg/dl, and low density lipoprotein (LDL) cholesterol by 17.5% from 229 to 189 mg/dl. Using density gradient ultracentrifugation, the major change in LDL cholesterol was found to be in those fractions with a mean density between 1.034 and 1.042, where cholesterol concentrations decreased from 132 to 87 mg/dl (34%). These results indicate that diet therapy with free-cholesterol and a high ratio of P/S is highly effective in controlling plasma cholesterol levels in heterozygous familial hypercholesterolemia.

Adult↗
PubMed1990

Chronic ethanol exposure before injury produces greater immune dysfunction after thermal injury in rats.

Chronic alcoholics constitute a small but significant subgroup of burned patients. The effects of chronic alcohol exposure on immune function in burned patients has not to our knowledge been studied. This study was designed to determine the effect of chronic alcohol exposure before burn injury on immune function after injury in rats. Immune function assessed by in vivo chemotaxis and responsiveness of non-adherent splenocytes to both a T-cell mitogen, concanavalin A, and a B-cell mitogen, lipopolysaccharide, was measured at 4 days after a 20% BSA full-thickness burn injury and/or gavage of 2.4 gm/kg/day of ethanol for 14 days. Chronic ethanol ingestion before burn injury produced significant suppression in chemotaxis and response to lipopolysaccharide but not in response to concanavalin A. These results suggest that chronic alcohol exposure before injury can contribute to further impaired immune function after injury, and may lead to increased susceptibility to infection and increased mortality.

Alcoholism↗
PubMed1990

Antibodies to Borrelia burgdorferi in dogs in Hokkaido.

During 1985 to 1990, serum samples were obtained from 229 healthy dogs. The dogs lived in Hokkaido, known to be infested with ticks. An enzyme-linked immunosorbent assay (ELISA) was used to detect IgG and IgM antibodies against Borrelia burgdorferi HO14 and HP3, which were isolated from Ixodes ovatus and I. persulcatus in the area. IgG antibody to B. burgdorferi HO14 was detected in 8.8% (1985), 16.4% (1987) and 18.5% (1990). IgM antibody to the bacteria was detected in 1.8% (1987) and 2.5% (1990). Antibodies to the strain HP3 of B. burgdorferi were also detected in the serum samples of dogs, but the percentage of seropositive sample to the strain HP3 was lower than that to the strain HO14. Statistical differences were not noticed between pet and street dogs. No antibody to B. burgdorferi was observed in 13 beagle dogs as experimental animal.

Age Factors↗
PubMed1990

Cloning and nucleotide sequence of the Enterobacter aerogenes signal peptidase II (lsp) gene.

In Escherichia coli, prolipoprotein signal peptidase is encoded by the lsp gene, which is organized into an operon consisting of ileS, lsp, and three open reading frames, designated genes x, orf-149, and orf-316. The Enterobacter aerogenes lsp gene was cloned and expressed in E. coli. The nucleotide sequence of the Enterobacter aerogenes lsp gene and a part of its flanking sequences were determined. A high degree of homology was found between the E. coli ileS-lsp operon and the corresponding genes in Enterobacter aerogenes. Furthermore, the same five genes which constitute an operon in E. coli were found in Enterobacter aerogenes in the same order.

Amino Acid Sequence↗
PubMed1990

[Studies on the synthesis of condensed pyridazine derivatives. I. Synthesis and benzodiazepine receptor binding studies of 2-substituted-4,4a,5,6-tetrahydrobenzo[h]cinnolin-3(2H)-ones and related compounds].

A series of 2-substituted-4,4a,5,6-tetrahydrobenzo[h]cinnolin-3(2H)-ones and related compounds were synthesized and tested for their ability to displace [3H]diazepam from rat brain membranes. Among them, compounds bearing 4-methoxyphenyl, 4-chlorophenyl, or 4-methylphenyl group at the position-2 were found to have high affinity to the benzodiazepine receptor. 2-(4-Methoxyphenyl)-9-methyl- and 2-(4-methoxyphenyl)-9-methoxy-4,4a,5,6-tetrahydrobenzo[h]cinnolin- 3(2H)-ones (8b-14 and 8b-15, respectively) showed a potent affinity comparable to that of diazepam. These results suggest that a topographical planarity or pseudoplanarity of these molecules is essential for high affinity to the benzodiazepine receptor. The structure-activity relationships are discussed.

Animals↗
PubMed1990

[Studies on the synthesis of condensed pyridazine derivatives. II. Synthesis and anxiolytic activities of 2-aryl-4,4a,5,6-tetrahydropyridazino[4,3-c]quinolin-3(2H)-ones, 2-aryl-4a,5-dihydro-2H-(1)benzothiopyrano[4,3-c]pyridazin-3(4H)-ones, and related compounds].

A series of 2-aryl-4,4a,5,6-tetrahydropyridazino[4,3-c]quinolin-3(2H)- ones, 2-aryl-4a,5-dihydro-2H-(1)benzothiopyrano[4,3-c]pyridazin-3( 4H)-ones, and related compounds were synthesized and tested for their ability to displace [3H]diazepam from rat brain membranes in vitro, and to prevent bicuculline-induced convulsions in mice in vivo. Among them, 2-(4-chlorophenyl)-4a,5-dihydro-2H-(1)benzothiopyrano[4,3-c]pyr idazin-3(4H)- one (16b) showed remarkable activities both in vitro (Ki 48 nM) and in vivo (ED50 12.4 mg/kg, p.o.). The trans sulfoxide (19a) of 16b exhibited anxioselective pharmacological activities. Compound 19a was equipotent with diazepam in the anticonflict assay (Vogel type, rat, MED 10 mg/kg, p.o.) while exhibiting reduced muscle relaxation (rotarod test) and narcotic potentiation. The structure-activity relationships are discussed.

Animals↗
PubMed1990

Heartworm migration toward right atrium following artificial pulmonary arterial embolism or injection of heartworm body fluid.

Heartworms harboring in the pulmonary arteries migrated toward the right atrium following insertion of dead heartworms or heartworm-like silicone tubes, or intravenous injection of body fluid extract of a female heartworm. The migration occurred within 3 hr (early group) or 1 to 7 days (late group) after insertion of dead worms, 1 to 11 days after insertion of silicone tubes, and immediately after infusion of heartworm-body fluid. The cardiac output decreased to an unmeasurably low level, and the pulmonary arterial pressure was also reduced in the early group. Although the output decreased, the pulmonary arterial pressure and the total pulmonary resistance increased gradually in the late group. In dogs with heartworm migration, in which silicone tubes had been inserted, the changes in cardiopulmonary values were the same as those in dogs of the late group. In dogs to which the body fluid had been administered intravenously, the changes in cardiopulmonary values were well accord with those in the early group. The systemic blood pressure also fell immediately after the administration with the shock-like state. These results suggest that the death of a part of the heartworms may be closely associated with the migration of heartworms toward the right atrium through the pulmonary arterial embolism and/or shock-like reaction by heartworm body fluid.

Animals↗
PubMed1990

Pretreatment of human vascular smooth muscle cells with interleukin-1 enhances interleukin-6 production and cell proliferation (action of IL-1 on vascular smooth muscle cells).

Systemic vasculitis is an inflammatory disorder of blood vessels characterized by a perivascular mononuclear cell infiltration around the vessel and fibrinoid necrosis within vessel walls. Interleukin-1 (IL-1) is a multipotent inflammatory mediator and affects several properties of vascular cells. To determine whether IL-1 could contribute to the pathogenesis of vascular diseases, we examined the effect of IL-1 on B cell stimulatory factor-2/interleukin-6 (IL-6) production by cultured human vascular smooth muscle cells (SMC) and the proliferation of these cells. Supernatants of SMC stimulated IgM synthesis of human B cell line. SKW6-CL4 cells. This activity was increased (1.7 to 2.6-fold) when SMC were pretreated with IL-1 or calcium ionophore A23187 for 48 h, and was completely blocked by rabbit anti-human IL-6 antibodies. These IL-6 activities of the SMC supernatants were also assessed by using an IL-6 dependent murine hybridoma cell line. MH-60. BSF-2. In addition, we observed that pretreatment of SMC with IL-1 for 48 h stimulated growth of SMC during the 96 h incubations, as assessed by cell number (p less than 0.05). These results suggest that IL-1 may contribute to the pathogenesis of inflammatory and immunological vasculitis by the augmentation of IL-6 release and growth of SMC.

Calcimycin↗
PubMed1990

[Heterogeneity of restriction enzyme cleavage pattern of molluscum contagiosum virus DNA].

The total NDAs obtained from a clinically atypical molluscum contagiosum (MC) found in a 47-year-old, male immunosuppressed renal allograft recipient and from seven MC of usual infantile cases were digested with BamHI restriction enzyme and analyzed by agarose gel electrophoresis. Three different cleavage patterns were observed and tentatively named MCV-a, -b and -c. All the infantile cases were infected by either MCV-a or MCV-b, both of which showed similar cleavage patterns. In contrast, the immunosuppressed patient was infected by MCV-c, whose cleavage pattern was quite different from those of MCV-a and -b. These results clarified the heterogeneity of MCV in Japanese patients with MC and implied the correlation between MCV types and clinical features of MC.

Child↗
PubMed1990

[A case of systemic lupus erythematosus complicated with multifocal posterior pigment epitheliopathy].

Multifocal posterior pigment epitheliopathy (MPPE) is a rare complication of systemic lupus erythematosus (SLE) and resistant to treatment. We here report a case of SLE with MPPE, successfully treated with prednisolone (PSL) and laser photocoagulation therapy. A 38-year-old woman, who had suffered from SLE for four years, was admitted to our hospital with the complaints of left hemiparesis, right homonymous hemianopsia, and dysarthria. The findings of MRI suggested her symptoms were caused by cerebrovascular involvement of SLE. The treatment with prednisolone was started at a dose of 100 mg per day. While the dose of PSL was reduced, she began to complain of paresthesia in left face and myodesopsia of left eye. Based upon the result of fluorescein angiogram, the diagnosis of MPPE was made. Since MPPE accompanied exacerbation of neurological manifestation, we considered that MPPE was a symptom of vascular involvement of SLE. MPPE was treated with laser photocoagulation therapy and an increased dosage of PSL, with favorable results. It has not been reported, as far as we concern, that laser photocoagulation therapy is effective for MPPE caused by SLE. This case is important for the pathogenesis and therapy of MPPE with SLE.

Adult↗
PubMed1990

Assignments of the iminoproton resonances of Bombyx mori tRNA(UCCGly) and the comparison of its structure and stability with those of tRNA(GCCGly).

Most of the iminoproton resonances in the 1H-NMR spectrum of Bombyx mori tRNA(UCCGly) have been assigned by the sequential NOEs. Any peak which indicates the presence of the tertiary GC base pair between the D and T loops could not be detected. The effects of temperature and the addition of magnesium ions and spermine on the 1H-NMR spectrum of this tRNA were examined. From the temperature change, it was found that the acceptor stem and the D stem in Bombyx mori tRNA(UCCGly) are equally stable even in the absence of magnesium, which is different from tRNA(GCCGly) where the D stem is not so stable.

Animals↗