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Biomedical subjects

K Asai

Publications and source records attributed to K Asai.

At least 163 records · Page 9Linked to original sources
PubMed1995

Expression of kinA and accumulation of sigma H at the onset of sporulation in Bacillus subtilis.

Induction of the Bacillus subtilis kinA gene, which codes for a major kinase of the phosphorelay pathway, required the spo0H gene, coding for the sigma H protein, but not the genes spo0A, spo0B, and spo0F at the onset of sporulation. Also, the levels of sigma H in spo0A, spo0B, and spo0F mutants were increased at the onset of sporulation, though induction of spo0H transcription in all of these mutants was appreciably inhibited. In addition, kinA expression was almost completely eliminated in a medium supplemented with excess glucose and glutamine, even though the usual stationary-phase-associated increase in sigma H was observed under these conditions.

Bacillus subtilis↗
PubMed1995

Corticotropin releasing hormone in colonic mucosa in patients with ulcerative colitis.

Corticotropin releasing hormone (CRH) is a key hormone in integrated response to stress, acting as the major regulator of the hypothalamic-pituitary-adrenal axis. Recently, local production of CRH has been detected in normal human colonic enterochromaffin cells. CRH is locally secreted in granulomatous and arthritic tissues in rats and humans, where it seems to act as a local proinflammatory agent. To find out if CRH is present in colonic tissues of patients with ulcerative colitis, this study examined the expression of this peptide in the large bowel of patients with ulcerative colitis. Colonic tissues of patients with ulcerative colitis obtained by endoscopic biopsy were immunostained with anti-CRH antibody. CRH messenger (m) RNA was also examined in biopsy specimens of ulcerative colitis by the reverse transcribed polymerase chain reaction method and by in situ hybridisation. Considerably enhanced expression of immunoreactive CRH was found in mucosal inflammatory cells. Intense staining with anti-CRH antibody was also shown in mucosal macrophages. CRH mRNA was expressed in mucosal epithelial cells. The expression of immunoreactive CRH in colonic mucosal epithelial cells of ulcerative colitis slightly increased, but not significantly, compared with normal colonic mucosal epithelial cells. These results suggest that CRH may play a part in the modulation of intestinal immune and inflammatory system, and as a modulator in the pathogenesis of ulcerative colitis.

Adult↗
PubMed1995

[Improvement of olfactory disturbance by endoscopic endonasal surgery for chronic sinusitis].

Olfactory disturbance is the one of the most important symptoms of chronic sinusitis. In the present study, we followed up the postoperative clinical course of olfactory disturbance in patients who underwent surgery for chronic sinusitis. Ninety patients with severe olfactory disturbance or anosmia who underwent endoscopic endonasal surgery for chronic sinusitis with severe olfactory disturbance or anosmia in the preceding three-year period were enrolled in this study. We obtained a high postoperative improvement rate of 78.8%. We compared and examined our cases' postoperative clinical course concerning their olfactory disturbance and various factors in other patients before and after surgery, and obtained the following results: a) Young patients, 30 years old or under at the time of surgery, showed significantly higher rates of improvement than patients who were 50 years old or more at the time of surgery. b) Even though revision surgery was performed, the improvement rates were almost the same as after the initial surgery. c) Although the Alinamin intravenous olfaction test is regarded as an olfaction threshold test, we have seen quite a few cases in which improvement was achieved despite the absence of a preoperative response to the Alinamin intravenous olfaction test. d) There was no clear correlation between the presence of preoperative lesions of the ethmoid sinus and the olfactory cleft and the improvement rates. e) The cases with unsatisfactory results concerning the paranasal sinuses and nasal cavity--those accompanied by postoperative adhesions of the olfactory cleft, recurrence of polyps, etc.,--showed significantly lower improvement rates than cases with satisfactory postoperative results. During surgery in patients with severe olfactory disturbance, we conclude that it is particularly important to adequately clean the lesions of the olfactory cleft and the anterior and posterior ethmoid sinus endoscopically. This ensures leaving clear the olfactory cleft.

Adult↗
PubMed1995

[Peripheral blood stem cell transplantation for rapidly spreading myeloma].

We report a case of rapidly spreading myeloma of immature cell morphology treated by peripheral blood stem cell transplantation (PBSCT). A 54-year-old man had a right orbital tumor, which subsequently was removed and proved to be plasmacytoma. Three years later a mass lesion appeared in his left lung and bilateral kidneys. The specimen obtained at lung biopsy confirmed the diagnosis of plasmacytoma. Serum M-protein, IgG lambda was increased, but there was no increase in plasma cells in the bone marrow. Since chemotherapy with VAD did not show any improvement, a high dose etoposide (500 mg/day, 4 days) was administered. When bone marrow suppression recovered, PBSCs were harvested (3.3 x 10(6)/kg). After conditioning therapy with cyclophosphamide (2.0 g/day, 2 days), etoposide (200 mg/day, 3 days) and ranimustine (200 mg/day, 2 days), the stored PBSCs were injected. Minor response was obtained and he was discharged. 2 months thereafter, it was found that plasma cells increased in the bone marrow. He died of pulmonary bleeding soon. Autopsy revealed immature plasma cell infiltration in multiple organs including the heart, liver, spleen, kidneys, intestine, bone and bone marrow.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

[Indications for endoscopic sinus surgery. A clinical study on patients with a poor post-operative course].

One hundred and fifty-three patients with chronic sinusitis underwent endoscopic endonasal sinus surgery. They were preoperatively evaluated on the basis of their complaints, the severity of nasal polyps, X-ray findings, and axial and/or coronal CT scans. Postoperative degree of improvement in their complaints and endoscopic findings in the nasal cavity and sinus cavities were assessed. Most patients, including those with severe maxillary sinusitis, had a good postoperative course. The percentage of improvement in their complaints was 99.3%. Even in the case of olfactory disturbance, which is the most difficult symptom to treat, the percentage of improvement was 81.0%. There were only 8 patients with complaints and pathological findings in their nose or sinuses after the operation, 4 with allergic rhinitis and/or asthma, 1 with severe inflammation of the olfactory cleft, 1 with thickening of the bone in the sinuses after a 25-year history of sinusitis without treatment, and 2 with narrowing of the antrostoma at the middle meatus after the operation.

Adolescent↗
PubMed1994

Astrocytic contribution to functioning synapse formation estimated by spontaneous neuronal intracellular Ca2+ oscillations.

Glial contribution to in vitro synaptic function was investigated in a neuron-glia co-culture system by monitoring spontaneous oscillations of intracellular Ca2+ in neurons. Rat cortical neurons, grown stably on a cortical astrocyte monolayer, extended neurites resulting in marked functional synapse formation. Little synapse formation was observed in neuronal co-culture with meningeal fibroblasts or endothelial cells. Aged astrocytes in vitro (C35) were found to attenuate synaptic development, while young astrocytes (C5) markedly promoted synaptic function. C5 and C35 astrocyte media conditioned yielded no significant synaptogenic effect, indicating diffusible factor(s) are not responsible for our observation. Modulation of astrocytic proliferation and differentiation by gliostatin, a glial growth inhibitor, or dibutyryl cAMP affected neuronal synaptic function on the co-cultures. Site-specific analysis in homologous and heterologous neuron-astrocyte co-cultures among cortex, hippocampus, septum, and striatum revealed that homologous combinations of neurons and astrocytes derived from identical brain regions elicited the largest number of synchronizing neurons. These results suggest that in vivo neuronal synaptic function essentially requires the participation of adjacent astrocytes, which is site-specific and age-dependent.

Animals↗
PubMed1994

The identification of Escherichia coli ispB (cel) gene encoding the octaprenyl diphosphate synthase.

The gene located upstream of the nlp gene at min 69 on the chromosome of Escherichia coli was cloned from the plasmid pLC7-42 constructed by Clarke and Carbon. The extract of the strain harboring the plasmid containing this gene showed increased activity of the prenyltransferase. The product of the enzyme reaction was analyzed by two systems of the thin-layer chromatography and shown to be the phosphate ester of all-E-octaprenol. These results suggested that the gene was the structural gene for the octaprenyl diphosphate synthase which supplied the precursor of the side chain of the isoprenoid quinones.

Alkyl and Aryl Transferases↗
PubMed1994

Expression of a heterodimeric (placental-intestinal) hybrid alkaline phosphatase in KB cells.

A hybrid heterodimeric alkaline phosphatase expressed in KB cells, consisting of placental and intestinal (fetal) subunits, was purified by use of two different immunoaffinity columns using the monoclonal antibodies 2HIMS-1 and HPMS-1. The closely related subunits were found to yield a dimeric active enzyme glycosylated as the mature heterodimeric forms. This enzyme displays intermediate properties to the placental and intestinal (fetal) isozymes with regard to heat stability, inhibition patterns with amino acids and amino acid derivatives, as well as reactivity with monoclonal antibodies specific for human alkaline phosphatase isozymes. Peptide fragments obtained from the hybrid enzyme after cyanogen bromide cleavage belong to either the placental or intestinal (meconial) isozyme as evaluated by SDS polyacrylamid gel electrophoresis, and the N-terminal amino acid sequences, corresponding to the placental and intestinal subunits, can be identified in the peptide fragments. By N-glycanase digestion or tunicamycin treatment, the molecular mass of the subunits was reduced to 62 kDa compared to 69 kDa for the native ones. The results confirm that some cell lines can synthesize hybrid alkaline phosphatases.

Alkaline Phosphatase↗
PubMed1994

Human neuroblastoma growth inhibitory factor (h-NGIF), derived from human astrocytoma conditioned medium, has neurotrophic properties.

Investigations on the general characteristics of human astrocytoma cell line NAC-1 revealed neuroblastoma growth inhibitory activity in conditioned medium. Neuroblastoma growth inhibitory factor (NGIF) was partially purified by Econo Q, Econo CM, and Superose 12 column chromatography. The protein is weakly basic with an estimated M(r) of 120,000, possibly having an M(r) 60,000 dimeric structure. NGIF inhibits the growth of human neuroblastoma cell lines but has no effect on morphology nor does it produce any change in the growth of human glioblastoma cell lines. Interestingly, NGIF appears to promote survival and neurite outgrowth of embryonal rat cortical neurons. These neurotrophic properties suggest a role for NGIF in the development of the nervous system.

Animals↗
PubMed1994

Anti-idiotypic monoclonal antibody recognizes a consensus recognition site for phosphatidylserine in phosphatidylserine-specific monoclonal antibody and protein kinase C.

In order to elucidate the molecular mechanisms responsible for the specific lipid-protein interactions, we have undertaken structural and idiotypic analyses of a monoclonal antibody, PS4A7, which binds specifically to phosphatidylserine (PS). Here we showed that one of the anti-idiotypic monoclonal antibodies raised against PS4A7 cross-reacted extensively with protein kinase C (PKC) and inhibited the activation of the enzymatic activity. The binding of the anti-idiotypic antibody to PKC was inhibited specifically by PS, but not by other phospholipids including 1,2-diacyl-sn-glycero-3-phospho-D-serine or 1,2-diacyl-sn-glycero-3-phospho-L-homoserine. In contrast, the binding of the anti-idiotypic mAb to the enzyme was significantly enhanced in the presence of either diacylglycerol or sphingosine. These findings indicate that the PS-specific monoclonal antibody and PKC share a consensus structure which is responsible for the specific interaction with PS and both diacylglycerol and sphingosine may induce a similar conformational change which exposes the PS-specific binding site of the enzyme.

Amino Acid Sequence↗
PubMed1994

Aberrant production of gliostatin/platelet-derived endothelial cell growth factor in rheumatoid synovium.

OBJECTIVE: To purify a protein inhibitor from rheumatoid arthritis (RA) synovial fluids which suppresses the apparent incorporation of 3H-thymidine into fibroblasts and synovial cells, and to define its biochemical features that have clinical relevance to the pathogenesis of RA. METHODS: Several standard chromatographic techniques were employed for the purification of the protein. Immunochemical methods with monoclonal antibody were used to quantify and visualize the protein in sera, synovial fluids, and tissues from RA patients. RESULTS: The chemical properties of purified inhibitor from RA synovial fluids confirmed its identity as gliostatin/platelet-derived endothelial cell growth factor (PD-ECGF), a potent angiogenic factor. The gliostatin/PD-ECGF level in synovial fluid and serum was higher in RA patients than in osteoarthritis controls. CONCLUSION: These findings strongly suggest that gliostatin/PD-ECGF might play an important role in the aberrant neovascularization of rheumatoid synovium.

3T3 Cells↗
PubMed1994

Chelation of copper reduces inhibition by oxidized lipoproteins of endothelium-dependent relaxation in porcine coronary arteries.

We examined the effect of dialyzing oxidized low-density lipoprotein (oLDL) against Krebs-Ringer solution, in the absence (yielding d-oLDL) or presence (yielding EDTA-oLDL) of ethylenediamine tetraacetic acid (EDTA), to investigate the mechanism that underlies the inhibition of endothelium-dependent relaxation (EDR) by o-LDL. Oxidation of LDL by exposure to Cu2+ resulted in the formation of a thiobarbituric acid-reacting substance (TBARS) and lipid hydroperoxide (LPO). At a concentration of 5 mg/dl, d-oLDL markedly attenuated EDR in the porcine coronary artery. Analysis of d-oLDL by gel filtration revealed that TBARS was ditributed in both the lipoprotein and the aqueous phases, whereas LPO was present only in the lipoprotein particles. Lysophosphatidylcholine (LPC), which has been suggested to be responsible for the impairment of EDR by oLDL, was present not only in the lipoprotein but also in the aqueous phase. However, EDR inhibitory activity was observed only in the oLDL particles, not in the aqueous phase. Almost all Cu2+ associated with the oLDL particles was removed by dialysis of oLDL against Krebs-Ringer solution containing EDTA. EDTA-oLDL or native LDL, at concentrations as high as 75 mg/dl, exerted only a moderate inhibitory action on EDR, Both TBARS and LPO in EDTA-oLDL were distributed only in the lipoprotein particles, not in the aqueous phase. These results demonstrate that the impairment of EDR by oLDL is related both to LPO and to transition metal ions such as Cu2+ associated with the lipoprotein particles, not to the amount of the TBARS or negative charge, and that factors other than LPC may affect EDR.

Animals↗
PubMed1994

Comparative toxicity of oxidatively modified low-density lipoprotein and lysophosphatidylcholine in cultured vascular endothelial cells.

Oxidative modification of low-density lipoprotein (LDL) may play an important role in the initiation and progression of atherosclerosis. We previously showed that the cytotoxicity of oxidized LDL (oxLDL) depended on the level of lipid hydroperoxides. Meanwhile, it has been shown that during LDL oxidation, a significant part of the LDL phosphatidylcholine (PC) is degraded to lysophosphatidylcholine (LPC) by an intrinsic phospholipase A2-like activity, and that LPC is toxic to various cells. In the present study, we compared the toxicity of oxLDL with that of LPC in cultured bovine aortic endothelial cells. Cytotoxicity induced by LPC, assessed by the release of lactate dehydrogenase (LDH), reached a plateau within 1 h. LDH release induced by oxLDL occurred much later, at about 3 h, and increased linearly until nearly all the LDH was released at 10 h. The addition of deferoxamine, a Fe3+ chelator, to the reaction medium prevented the toxic effects of oxLDL, but not of LPC. Native LDL and oxLDL inhibited the toxicity of LPC, while native LDL promoted the toxicity of oxLDL. Albumin inhibited the toxicity of LPC but not of oxLDL. Preincubation of endothelial cells with an antioxidant, probucol, protected against oxLDL toxicity, but not against LPC toxicity. These results suggest that lipid hydroperoxides associated with the oxLDL particle, not LPC, constitute the toxic moiety of oxLDL. These substances may generate lipid peroxyl and alkoxyl radicals in the presence of ionic iron, probably from intracellular iron stores in endothelial cells, and produce cytotoxicity.

Animals↗
PubMed1994

Platelet 3H-paroxetine binding in control subjects and depressed patients: relationship to serotonin uptake and age.

3H-paroxetine is regarded as a better ligand for the serotonin (5-hydroxytryptamine; 5-HT) uptake site than 3H-imipramine. In the present study, platelet 14C-5-HT uptake and 3H-paroxetine binding were simultaneously measured in 12 control subjects. There was a significant positive correlation between the individual Bmax value for 3H-paroxetine binding and the Vmax value for 14C-5-HT uptake. Platelet 3H-paroxetine binding was also determined in 21 drug-free patients who satisfied DSM-III-R criteria for major depression and 21 control subjects. A negative correlation was found between the Bmax values for 3H-paroxetine binding with age in control subjects. There was no change in 3H-paroxetine binding in depressed patients compared with control subjects. Our results indicated that 3H-paroxetine was a good ligand for evaluating 5-HT uptake sites, and the influence of age ought to be taken into consideration in the study of 3H-paroxetine binding. The present study indicated that there was no change in 5-HT uptake sites in platelets from depressed patients.

Adult↗
PubMed1994

Recombinant human granulocyte colony-stimulating factor augments cytotoxicity of OK-432-induced polymorphonuclear leukocytes.

Polymorphonuclear leukocytes (PMNs) recovered from the peritoneal cavity of mice treated with the streptococcal preparation OK-432, exhibited strong cytotoxicity after the in vitro addition of Nocardia rubra cell wall skeleton (N-CWS). In this study, we investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) could augment the cytotoxicity of OK-432-induced PMNs after the addition of N-CWS in vitro. PMNs recovered from the peritoneal cavity of 8- to 10-week-old, male C3H/He mice induced by intraperitoneal (i.p.) injection of 50 KE/kg (1 KE = 0.1 mg) of OK-432 were used in a 51Cr release assay against MM46 mammary carcinoma cells. While addition of rhG-CSF in vitro did not augment the cytotoxicity of OK-432-induced PMNs, marked augmentation of the cytotoxicity of OK-432-induced PMNs was observed following a single subcutaneous (s.c.) or i.p. injection of 125 micrograms/kg of rhG-CSF. The effect of in vivo administered rhG-CSF was dependent on the timing of the injection with respect to OK-432 administration and differed from s.c. or i.p. injections. Interestingly, the cytotoxicity of OK-432-induced PMNs was rather weak following consecutive s.c. or i.p. administration of rhG-CSF for 7-14 days. H2O2 is likely involved in mediating the cytotoxicity of OK-432-induced PMNs since activity was significantly reduced by the in vitro addition of low concentration of catalase. Generation of H2O2 by the PMNs correlated with cytotoxicity. These results suggest that in vivo administration of rhG-CSF augments the cytotoxicity of OK-432-induced PMNs in a time dependent fashion and that H2O2 plays an important role in mediating their cytotoxicity.

Animals↗
PubMed1994

An early-onset case of multiple sclerosis with thalamic lesions on MRI.

We present here an early-onset case of multiple sclerosis (MS) with thalamic lesions. The patient first experienced an episode of ataxic gait at 2 years 3 months of age, with spontaneous remission within 1 month. At 5 years 4 months, she was admitted because of cerebellar ataxia, oculomotor restriction and feeding difficulty. Magnetic resonance imaging (MRI) showed multiple well-defined lesions in the white matter of the cerebellum, mid-brain, periventricle and right frontal lobe. Cerebrospinal fluid (CSF) showed a mild elevation of both immunoglobulin G (IgG) and myelin basic protein (MBP). Serum anti-myelin antibody was also positive, although leukocytosis and elevation of C-reactive protein were not found. Methylprednisolone pulse therapy relieved symptoms within 2 weeks and the abnormal MRI and CSF findings gradually improved. At 6 years 6 months of age, she incurred a third episode of cerebellar ataxia and disturbance of consciousness. Magnetic resonance imaging revealed recurrence and extension of the previous lesions as well as new lesions in the thalamus and internal capsule. CSF IgG and MBP level showed a higher elevation than in the second episode. The combination of the cerebellar, brain-stem, cerebral and thalamic lesions with remission and exacerbation, supported by MRI and CSF findings, allowed the diagnosis of clinically definite MS to be made. This is one of the youngest cases of MS yet described, with the first attack occurring at 27 months of age. In addition, this case is unique for the involvement of the gray matter in the thalamus.

Age Factors↗