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Biomedical subjects

K Takase

Publications and source records attributed to K Takase.

At least 199 records · Page 11Linked to original sources
PubMed1992

Site-directed mutagenesis of active site residues in Bacillus subtilis alpha-amylase.

Site-directed mutagenesis of Bacillus subtilis N7 alpha-amylase has been performed to evaluate the roles of the active site residues in catalysis and to prepare an inactive catalytic-site mutant that can form a stable complex with natural substrates. Mutation of Asp-176, Glu-208, and Asp-269 to their amide forms resulted in over a 15,000-fold reduction of its specific activity, but all the mutants retained considerable substrate-binding abilities as estimated by gel electrophoresis in the presence of soluble starch. Conversion of His-180 to Asn resulted in a 20-fold reduction of kcat with a 5-fold increase in Km for a maltopentaose derivative. The relative affinities for acarbose vs. maltopentaose were also compared between the mutants and wild-type enzyme. The results are consistent with the roles previously proposed in Taka-amylase A and porcine pancreatic alpha-amylase based on their X-ray crystallographic analyses, although different pairs had been assigned as catalytic residues for each enzyme. Analysis of the residual activity of the catalytic-site mutants by gel electrophoresis has suggested that it derived from the wild-type enzyme contaminating the mutant preparations, which could be removed by use of an acarbose affinity column; thus, these mutants are completely devoid of activity. The affinity-purified mutant proteins should be useful for elucidating the complete picture of the interaction of this enzyme with starch.

Acarbose↗
PubMed1992

Single- and multiple-dose pharmacokinetics of intravenous cefpirome (HR810) to healthy volunteers.

The safety and pharmacokinetics of single and multiple administrations of cefpirome (HR810), a new cephalosporin antibiotic agent with a broad antibacterial spectrum, were studied in healthy male volunteers. The single administration protocols included a 3-minute intravenous injection of 0.5 g or 1 g, and a 1-hour intravenous drip infusion of 0.5 g, 1 g, or 2 g. The multiple administration protocols included nine intravenous injections and 1-hour intravenous drip infusions of 1 g of cefpirome twice a day at intervals of 12 hours. Cefpirome was tolerated, and only a few mild, subjective and hepatic-function side effects were observed. There were no severe abnormalities. The drug concentrations in the plasma and the urine were determined by means of HPLC and bioassay, and the results correlated well (r = 0.99). The pharmacokinetic parameters were calculated using a two-compartment model. The elimination half-life (t1/2 beta) was about 1.7 hours for both intravenous injection and intravenous drip infusion and was not dose-dependent. AUC and Cmax were dose-dependent in this study, although an accumulation due to multiple administrations was not observed, and there were no changes in the pharmacokinetic parameters after the initial and the final administrations. The recovery rate of the unchanged compound in the urine was more than 80% in the 24 hours after a single administration and was the same after multiple administrations. Bioautography did not show any active metabolites in the plasma or the urine. The results, for safety and pharmacokinetics, show that cefpirome can be expected to have excellent clinical efficacy for bacterial infections.

Adult↗
PubMed1992

Studies on gross footpad lesions of chickens infected with avian reoviruses via the footpad route.

Avian reoviruses grew well in the footpad of chickens inoculated with the viruses via the footpad route, resulting in gross footpad lesions of swelling. The gross footpad lesions induced under some different conditions were investigated for 14 days by two methods. In method A, the lesions were observed grossly and graded as lesion scores 0 to 4. In method B, they were expressed as a swelling index assessed by relative thickness of an inoculated footpad to uninoculated. Both methods are successful, and similar results were obtained. Gross footpad lesions were produced in all chickens aged 9 to 310 days, and the younger were the birds at infection, the earlier and severer were the lesions observed. The lesions began to appear late when the virus titer inoculated was low. It has been elucidated that severity of the lesions depends on virus strains, not on the sexes of chickens.

Age Factors↗
PubMed1992

Peroxidase-negative and myelomonocytic antigen-positive acute leukemia.

Between 1983-1988 bone marrow samples obtained from 195 peroxidase-negative leukemia patients were analyzed for their surface antigens. Thirteen of these patients (6.7%) had myelomonocytic-positive and lymphoid-negative antigens. These leukemic cells reacted with CD13 in eight patients, CD33 in seven, CD11 in six and CDw41 in two. In none of these patients did the leukemic cells react with CD1, CD2, CD3, CD4, CD5, CD8, CD10, CD19 or CD20. Leukemic cells from two patients were reactive with CD7. These leukemic cells demonstrated L2 morphology in 11 patients and L1 morphology in one patient. The leukemic cells from the final patient were diagnosed as those of leukemic transformation of myelodysplastic syndrome. Chromosomal abnormality was observed in approximately half of the patients examined (6/10). Cytochemical analysis revealed that the leukemic cells were negative for periodic acid Schiff stain but positive for acid phosphatase. The prognosis of these patients was markedly poor as compared to acute lymphocytic leukemia or typical peroxidase-positive nonlymphocytic leukemia. Complete remission was induced in only 30% of patients and duration of survival was short (4.7 months). This suggests that myelomonocytic antigen-positive peroxidase-negative acute leukemia is a distinct type of leukemia and may require more aggressive therapy to improve survival.

Acid Phosphatase↗
PubMed1992

Efficacy of a herbal medicine "sho-saiko-to" on the improvement of impaired cytokine production of peripheral blood mononuclear cells in patients with chronic viral hepatitis.

Peripheral blood samples were collected from normal subjects and chronic viral hepatitis patients, and the in vitro capability of the peripheral blood mononuclear cells to produce various cytokine (interleukin-1 beta, interleukin-6, interferon-gamma, and granulocyte-macrophage colony-stimulating factor) were analyzed by adding pokeweed mitogen. We then investigated the effects of a herbal medicine "Sho-saiko-to" on the levels of cytokine production. The production levels of the 4 cytokines were significantly lower in the peripheral blood mononuclear cells of the patients (Patient Group) than in those of normal subjects (Control Group). The addition of Sho-saiko-to to the Patient Group resulted in improved productions of those cytokines, as well as an remarkable improvement of interleukin-1 beta production. The results demonstrated that Sho-saiko-to acts to improve such immunological abnormalities as decreased cytokine productions. Administration of Sho-saiko-to to chronic viral hepatitis patients is also expected to have immunological benefits.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Effects of the streptococcal preparation OK-432 on in vitro cytokine production of peripheral blood mononuclear cells in patients with chronic viral hepatitis.

We obtained peripheral blood mononuclear cells from 12 chronic hepatitis Type B patients, 12 Type C patients, and 15 healthy volunteers, and investigated the effects of OK-432, a streptococcal preparation, on in vitro production of 3 types of cytokines. Mononuclear cells in a concentration of 1 x 10(6) cell/ml were prepared in the culture medium. OK-432 (Chugai Pharmaceutical Co., Ltd., Tokyo) was added to this preparation and incubated for one to 4 days. Thereafter interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) levels in the culture supernatant were measured using enzyme-linked immunoassay kits. Cytokine production levels in cultures with OK-432 were significantly increased in the mononuclear cells of both patients and healthy volunteers. The largest increase was observed with IFN-gamma (p < 0.01), and then with IL-1 beta (p < 0.05). Responses of the cells from chronic hepatitis Type C patients to OK-432 were relatively good. When interferon (alpha and beta) treatment was first introduced, there were high hopes for a high efficacy. However, we now know 50-70% of patients with chronic hepatitis Type C do not respond satisfactorily to interferon. Some physicians suggest the necessity of using biological response modifier (BRM) as an adjuvant treatment for these patients. From our findings, OK-432 could be a useful BRM in patients with chronic hepatitis Type C.

Cells, Cultured↗
PubMed1992

Alpha adrenoceptor subtypes involved in the emetic action in dogs.

In order to assess the involvement of alpha-1 and alpha-2 adrenoceptors in emesis, the emetic effect of eight alpha agonists was studied in dogs. The i.m. administration of each agonist elicited dose-dependent emesis. The order of potency in inducing emesis was: clonidine greater than oxymetazoline greater than tramazoline greater than naphazoline greater than xylazine greater than epinephrine greater than methoxamine = phenylephrine. The clonidine-induced emesis was antagonized by adrenoceptor antagonists showing alpha-2 blocking activity, yohimbine, tolazoline and phentolamine. Among these antagonists, yohimbine was the most effective. The alpha-1 and beta adrenergic, cholinergic, dopaminergic, histaminergic, serotonergic and opioid receptor antagonists did not prevent the clonidine-induced emesis. The emesis induced by oxymetazoline, tramazoline, xylazine, naphazoline and epinephrine was also antagonized by a selective alpha-2 adrenoceptor antagonist, yohimbine, but not by a selective alpha-1 adrenoceptor antagonist, prazosin. In contrast, methoxamine and phenylephrine-induced emesis was antagonized by prazosin, but not by yohimbine. Neither yohimbine nor prazosin prevented the morphine- and histamine-induced emesis. These results indicate that alpha-2 adrenoceptors are involved in the mediation of emetic action, and that the alpha adrenoceptor-mediated emesis does not involve beta adrenergic, cholinergic, dopaminergic, histaminergic, serotonergic and opioid receptors in the emetic pathway. This study further suggests that alpha adrenoceptors involved in the emesis are mainly of the alpha-2 type, although the involvement of alpha-1 adrenoceptors cannot be ruled out.

Adrenergic alpha-Agonists↗
PubMed1992

Reversible G1 arrest induced by dimethyl sulfoxide in human lymphoid cell lines: kinetics of the arrest and expression of the cell cycle marker proliferating cell nuclear antigen in Raji cells.

In order to elucidate further the mechanism of reversible cell cycle arrest induced by treatment of Raji cells with 1.5% dimethyl sulfoxide (DMSO), we have performed a detailed analysis of the kinetics of arrest and of reentry into the cell cycle after removal of DMSO and have correlated cell cycle progression with expression of proliferating cell nuclear antigen (PCNA). No significant effect of DMSO on cell cycle patterns, assessed by flow cytometric analysis of bromodeoxyuridine-prelabeled cells, was seen for the first 19 h of treatment. A clear reduction of entry into S phase was detected by about 25 h of treatment; essentially all cells were arrested with a G1 content of DNA after 96 h of treatment. When DMSO-arrested cells were released from the block, entry into S phase began at 12 h after release and continued in a fairly asynchronous manner for a further 12-14 h. In arrested cells, the content of PCNA was reduced to about 25% of the amount present in logarithmically growing G1 phase cells. Six h after release from DMSO, PCNA RNA transcripts were first detected by Northern blotting. The increase of PCNA protein, detected by Western blotting, was seen by 9 h after release. The kinetics of entry into the cell cycle and restoration of PCNA protein are similar to that seen in serum stimulation of quiescent cells. These results suggest that DMSO reversibly arrests proliferation of Raji cells at G0 or at an early point in G1 phase and that progression through late G1 phase and entry into S phase are correlated with synthesis of the PCNA gene product.

Antigens, Neoplasm↗
PubMed1992

Correlation of carotid B-mode scanning with endarterectomy findings in Japanese patients.

In this study, 13 Japanese patients who underwent carotid endarterectomy with en bloc method were prospectively evaluated by high-resolution B-mode scanning. B-mode imaging was carried out 1-2 days before operation. The most suitable consecutive longitudinal planes of the carotid bifurcation were photographed (5-8 planes). The echogain was gradually changed from a lower to a higher intensity during B-mode scanning to identify the echogenicity of the atheromatous plaques. Three-dimensional reconstructions were made of the carotid plaques before performing carotid endarterectomy, and the author investigated the correlations between the echo characteristics and the histology of the resected plaques. The echogenicity of all atheromatous plaques, except for those with calcification, was lower than that of the normal medial layer of the vessel wall. The consecutive B-mode image data correlated well with the histological findings of the resected plaques in this study. In 2 out of 13 cases, it was found to be very difficult to distinguish an ulcerated plaque from a region of fresh intraplaque hemorrhage. High-resolution B-mode scanning was found to be a very useful and reliable method for identifying the detailed structure of atheromatous plaques in the cervical carotid artery.

Aged↗
PubMed1991

A case of acute intermittent porphyria with acute pancreatitis.

A case of acute pancreatitis in a 29-year-old female associated with an attack of acute intermittent porphyria (AIP) is reported. Following the attack of AIP, serum pancreatic amylase originating from the pancreas increased transiently, and mild swelling of the pancreas was detected by ultrasonography. On this basis acute pancreatitis was diagnosed. Additionally, this patient had mild hepatic dysfunction. Laparoscopy disclosed diffuse slightly dark bluish pigmentation on the irregular surface of the liver. Mild fibrous dilatation of the portal area with lymphocytic infiltration was seen histologically. Acute pancreatitis and hepatic damage with AIP is extremely rare, however it is possible that these findings are etiologically connected in this patient.

Acute Disease↗
PubMed1991

Expression of c-fos and c-myc in Raji Burkitt's lymphoma cells during the progression of DMSO-induced G1 cells into S phase.

Using flow cytometry, we have recently found that dimethyl sulfoxide (DMSO) reversibly induces G1-arrest in the cell cycle of human lymphoid cell lines such as Raji, Akata, and Molt-4. Here we investigated c-fos and c-myc expression in Raji Burkitt's lymphoma cells at DMSO-induced G1 arrest and after release from DMSO. A small but significant accumulation of c-fos mRNA was observed in G1-arrested Raji cells after treatment with 1.5% DMSO for 96 h. When G1-arrested Raji cells were transferred to DMSO-free medium, a transient increase in c-fos transcripts was detected 30-60 min after the release. The steady state level of c-myc transcripts in G1-arrested Raji cells was found to be one-third that in the log-phase cells. After removal of DMSO, the level of c-myc mRNA was restored and reached a maximum at 4.5-6 h. Immunoblot analysis with a monoclonal antibody against human c-myc protein indicated that c-myc protein in the G1-arrested cells was decreased less than one-tenth that in the log-phase cells. The level of c-myc protein gradually increased after the release from DMSO and reached a maximum at 6-9 h.

Blotting, Northern↗
PubMed1991

Fulminant hepatitis B: induction by hepatitis B virus mutants defective in the precore region and incapable of encoding e antigen.

Clones of hepatitis B virus were propagated from 10 cases of fulminant hepatitis B after amplification by polymerase chain reaction and their nucleotide sequences of the precore region were determined. All 113 clones from 9 cases had a point mutation from guanine to adenine at nucleotide 83 in the precore region, which converted codon 28 for tryptophan (TGG) to a stop codon (TAG) and prohibited the synthesis and secretion of hepatitis B e antigen. Precore-region defects were not detected in any of 23 clones from the remaining 1 case. By contrast, precore-region defects were not found in any of 180 clones from 8 cases of acute hepatitis B without hepatic failure serving as controls. The source of infection was traceable in 3 cases. The same precore-region defect, along with the sequence identity of 435 nucleotides, was observed in clones from the case of a baby and his grandmother, who carried the virus and was implicated in the transmission, and also in clones from two pediatricians and the carrier patients they attended. These findings support the hypothesis that precore-defective mutants have stronger activity to induce fulminant hepatitis than nondefective viruses.

Adolescent↗
PubMed1991

The protective effects of SA3443, a novel cyclic disulfide, on chronic liver injuries in rats.

The effects of (4R)-hexahydro-7,7-dimethyl-6-oxo-1,2,5-dithiazocine-4- carboxylic acid (SA3443), a novel cyclic disulfide compound, on the development of chronic liver injury were studied in rats, using two types of models, carbon tetrachloride (CCl4)-induced chronic liver injury and heterologous serum (swine serum)-induced liver fibrosis. SA3443 (30-100 mg/kg, p.o.) significantly suppressed increases in serum transaminase and alkaline phosphatase activity induced by CCl4-treatment for 10 weeks. This compound also inhibited increases in hepatic lipids and hydroxyproline content in CCl4-treated rats. In the histopathological studies, treatment with SA3443 resulted in a decrease in the degree of hepatic necrosis, fibrosis and steatosis. On the other hand, 8-weeks treatment with swine serum revealed hepatic fibrosis without appearance of necrosis or fatty accumulation. In this model, SA3443 (30 mg/kg, p.o.) reduced the hepatic hydroxyproline level, and diminished the formation of connective tissue in the liver. These findings indicate that SA3443 protects the liver against chronic liver injuries induced by CCl4 and heterogeneous serum.

Animals↗
PubMed1991

[The protective effect of (4R)-hexahydro-7, 7-dimethyl-6-oxo-1, 2, 5-dithiazocine-4-carboxylic acid (SA3443), a novel cyclic disulfide, on acetaminophen-induced liver injury].

Effects of (4R)-hexahydro-7, 7-dimethyl-6-oxo-1, 2, 5-dithiazocine-4-carboxylic acid (SA3443) on acetaminophen-induced liver injury were investigated in BALB/c mice. SA3443 (30-300 mg/kg, p.o.) dose-dependently suppressed the elevation of serum transaminase activities and the histological changes of liver induced by acetaminophen (150 mg/kg, p.o.). The compound at the same doses also reduced the mortality due to the lethal acute hepatic failure induced by acetaminophen (350 mg/kg, p.o.). Other hepatoprotective agents, cianidanol (500 mg/kg, p.o.), malotilate (100 mg/kg, p.o.), grycyrrhizine (10 mg/kg, i.p.) and cysteine (300 mg/kg, p.o.) similarly reduced it. SA3443 had no effect on glutathione (GSH) contents in the liver of normal mice, but it dose-dependently suppressed the decrease of GSH contents in the liver of BALB/c mice treated with acetaminophen. These results suggest that SA3443, a novel cyclic disulfide, provides considerable protection against acetaminophen-induced liver injury and that one of the modes of the hepatoprotective action of this compound is suppression of the decrease of GSH contents in the liver.

Acetaminophen↗
PubMed1991

The protective effects of (4R)-hexahydro-7,7-dimethyl-6-oxo-1,2,5-dithiazocine-4-carboxylic acid (SA3443), a novel cyclic disulfide, on chemically-induced acute liver injury.

The effects of SA3443, a novel cyclic disulfide compound, on acute liver injuries induced by carbon tetrachloride (CCl4), D-galactosamine and DL-ethionine were studied in rats or mice. SA3443 (100-300 mg/kg, p.o.) significantly suppressed the increases of serum transaminase activity and liver triglyceride content in the CCl4 or DL-ethionine-induced model. Furthermore, SA3443 (300 mg/kg, p.o.) clearly reduced the formation of hepatic lipid peroxide in CCl4-treated rats. These results indicate that SA3443 protects the liver against acute liver injury.

Alanine Transaminase↗
PubMed1991

[A transcranial Doppler method in the early diagnosis of cerebrovascular vasospasm; comparison with angiographical findings].

Cerebral angiography (CAG) and transcranial Doppler (TCD) were performed at the same time in 18 patients with ruptured aneurysms within 1-3 days after onset, and the results were compared. Delayed ischemic neurological deficits (DIND) accompanying vascular spasm were detected in 8 patients, but three of the 8 patients recovered from the DIND within about 2 weeks. The CAG findings were classified into the following 3 types: (1) diffuse type showing generalized spasm of intracranial arteries (8 patients), (2) proximal type with spasm in the distal part of the internal carotid arteries and/or proximal middle cerebral arteries (5 patients) and (3) peripheral type showing spasm in the peripheral part of the middle cerebral arteries (5 patients). The TCD findings could be classified into (a) high pattern type, in which the blood flow velocity had increased (13 cases), (b) paradoxical pattern type, in which the blood flow velocity was faster in the more peripheral regions (2 cases), and (c) normal pattern type (3 cases). All 13 patients classified as diffuse type (8 patients) or proximal type (5 patients) in terms of the CAG findings showed a high pattern in TCD, indicating that TCD is also capable of diagnosing vasospasm. On the other hand, two of the 5 patients with peripheral type also showed the paradoxical pattern while the remaining 3 showed the normal pattern in TCD. DIND was detected in 6 of the 15 patients with a high or paradoxical pattern in TCD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗