Search PubMed⌕ Search

Biomedical subjects

H Okabe

Publications and source records attributed to H Okabe.

At least 235 records · Page 13Linked to original sources
PubMed1994

Primary structure of bovine Hageman factor (blood coagulation factor XII): comparison with human and guinea pig molecules.

A bovine Hageman factor cDNA was cloned from a liver cDNA library. The nucleotide sequence was analyzed and the amino-acid sequence was deduced. The sequence deduced was consistent with the partial amino-acid sequences of bovine Hageman factor protein. The sequences for three portions including the amino terminal had been previously reported (Fujikawa et al. (1977) Biochemistry 16, 2270-2278). In comparison with the primary structures of human and guinea pig Hageman factors, the putative domain structures were totally conserved. Each domain possessed high sequence homology with the human molecule (66-88%) and the guinea pig one (63-81%) except for the proline-rich region (less than 10%) which connects the amino-terminal five domains with a serine proteinase portion. Significant heterogeneities were observed among the three species around the essential cleavage sites for the conversion to the activated Hageman factors. Bovine Hageman factor has no suitable amino-acid sequence as the substrate for the trypsin-type proteinases at the proline-rich region in difference from the human and guinea pig molecules. Probably this is the reason why the beta-form activated Hageman factor (the proteinase moiety) is not liberated in the activation of the bovine molecule with trypsin or plasma kallikrein.

Amino Acid Sequence↗
PubMed1994

Effect of nafamostat mesilate, a synthetic protease inhibitor, on tissue factor-factor VIIa complex activity.

Nafamostat mesilate (NM), a synthetic protease inhibitor, is frequently used for the treatment of disseminated intravascular coagulation (DIC) in Japan. NM inhibits several proteases which may be importantly involved in the pathophysiology of DIC. Since tissue factor (TF) plays a critical role in DIC associated with septicemia, inhibition of the extrinsic pathway of coagulation by coagulation inhibitors may be useful for the treatment of DIC. NM inhibited extrinsic pathway activity (TF-F.VIIa mediated-F.Xa generation) in a concentration dependent manner; the IC50 was 1.0 x 10(-7) M. F.Xa was not inhibited by NM at the concentrations used in the experiment, suggesting that NM might inhibit TF-F.VIIa complex activity. When incubated with TF-F.VIIa complex, NM inhibited the complex activity with an IC50 of 1.5 x 10(-7) M, the same value that found for inhibition of extrinsic pathway activity. A Lineweaver-Bulk's plot of the inhibition demonstrated that NM inhibited TF-F.VIIa complex in a competitive fashion, with an inhibition constant (Ki) of 2.0 x 10(-7) M. These findings suggested that NM may be a potent inhibitor of TF-F.VIIa complex and the therapeutic effect of NM in DIC patients could be partly explained by inhibition of the extrinsic pathway of the coagulation system.

Amino Acid Sequence↗
PubMed1994

Carbon tetrachloride increases sinusoidal efflux of reduced and oxidized glutathione in rats.

To elucidate the significance of the changes in plasma glutathione concentrations associated with carbon tetrachloride (CCl4)-induced liver damage, the changes in the concentrations of reduced (GSH) and oxidized glutathione (GSSG) in plasma as well as in the liver were investigated in rats. In the liver, the concentration of GSH decreased, and that of GSSG increased 24 hr after the intraperitoneal administration of CCl4. In the right atrial plasma, the concentration of both GSH and GSSG increased. The GSH/GSSG ratio in the plasma decreased as did that in the liver. The net sinusoidal efflux of GSH and GSSG from the liver was calculated by subtracting their concentrations in plasma of the infrahepatic inferior vena cava from those of the suprahepatic inferior vena cava. The net efflux of GSH and GSSG started to increase as early as 3-6 hr after CCl4 administration, and reached a plateau 6 and 24 hr after CCl4 administration, respectively. On the other hand, an elongation of prothrombin time and leakage of alanine aminotransferase reached a maximum 24 and 48 hr after CCl4 administration, respectively. Vacuolization in the centri-lobular region and inflammatory infiltration started 3 and 6 hr after CCl4 administration, respectively, and progressed for 48 hr. These results suggest that CCl4 induced an increase in plasma concentrations of GSH as well as GSSG by increasing their efflux from the liver, and that the changes in plasma glutathione status might be a useful and sensitive marker for CCl4-induced liver damage.

Animals↗
PubMed1994

Direct evidence for systemic fibrinogenolysis in patients with acquired alpha 2-plasmin inhibitor deficiency.

To examine whether or not acquired alpha 2-plasmin inhibitor deficiency is associated with systemic fibrinogenolysis, we analyzed the fibrin and fibrinogen degradation products in eight patients with this condition in various disease states. The underlying disease was gastric cancer in three patients, metastatic prostatic cancer in two, acute promyelocytic leukemia in two, and abdominal aortic aneurysm in one patient. In all eight patients, the alpha 2-plasmin inhibitor level was reduced to less than 50% of normal, and plasmin-alpha 2-plasmin inhibitor complex levels were increased. Immunoblotting of serum using an antifibrinogen antibody detected a 250 kDa protein (corresponding to fragments X or DY) in all eight patients. Fragment Y and D monomer were detected in seven of the eight patients, indicating the occurrence of systemic fibrinogenolysis. However, they were not detected in one patient with metastatic prostatic cancer. To determine whether or not fibrinogen degradation was also occurring in the patient without fragment Y, we characterized the 250 kDa protein in all eight patients. The protein was found to be fragment X in the metastatic prostatic cancer patient without fragment Y, while it was fragment DY in the other seven patients. Thus, systemic fibrinogenolysis was present in all eight patients. In the two patients with metastatic prostatic cancer, the level of alpha 2-plasmin inhibitor gradually increased with the reduction of tumor size by treatment. Fragment X, fragment Y, and D monomer were not detected when the alpha 2-plasmin inhibitor level exceeded 60% of normal in both patients. In the other six patients fragment Y and D monomer also disappeared when the alpha 2-plasmin inhibitor level exceeded 60% of normal. These findings suggest that systemic fibrinogenolysis only occurs when the plasma levels of alpha 2-plasmin inhibitor falls below 60% of normal due to activation of the fibrinolytic system by various pathological conditions.

Adult↗
PubMed1994

Plasma levels of granulocyte elastase-alpha 1-proteinase inhibitor complex in patients with disseminated intravascular coagulation: pathophysiologic implications.

To investigate the role of neutrophil activation in the pathophysiology and sequelae of disseminated intravascular coagulation (DIC), we measured plasma levels of granulocyte elastase-alpha 1-proteinase inhibitor complex (GEPIC) in 41 patients with DIC and 27 patients with similar underlying conditions but without DIC. Mean GEPIC levels were significantly higher in patients with DIC (421.0 +/- 45.6 ng/ml) than in patients without DIC (246.1 +/- 41.9 ng/ml, P < 0.01). Significant differences were also noted in DIC patients with or without infection (474.7 +/- 61.2 ng/ml vs. 302.4 +/- 48.9 ng/ml, P < 0.04), with or without organ dysfunction (546.6 +/- 72.7 ng/ml vs. 305.6 +/- 42 ng/ml, P < 0.01), and with or without respiratory failure (640.0 +/- 91.2 ng/ml vs. 328.1 +/- 55.1 ng/ml, P < 0.01). No significant difference was found in mean GEPIC levels in DIC patients with or without renal failure, heart failure, hepatic failure, or gastrointestinal bleeding. The frequency of respiratory failure correlated with rising plasma levels of GEPIC. Mortality was higher in patients with GEPIC levels > 500 ng/ml (53.8%) than in patients with GEPIC levels < 500 ng/ml (28.6%). This correlation was particularly strong in patients with DIC, infection, and respiratory failure. Based on these data, we suggest that neutrophil activation, triggered by the coagulation cascade and perhaps augmented by endotoxin or cytokine release with infection, significantly contributes to respiratory failure and mortality in patients with DIC.

Cardiac Output, Low↗
PubMed1994

Measurement of free and total hydroxyproline by automated flow injection of serum or urine samples from maintenance hemodialysis patients with renal osteodystrophy.

An automated measurement of total and free hydroxyproline in serum or urine is presented that uses flow injection analysis. After exclusion of nonspecific substances, hydroxyproline was oxidized by chloramine-T and L-cysteine with Ehrlich's reagent. The linearity obtained was from 3.8 mumole/L to 1.22 mmole/L with good precision (CV < 3%). Comparison of the proposed method with HPLC yielded r = 0.939 as the correlation coefficient. Reference intervals of free and total hydroxyproline are 1.4-9.7 mumole/L, 3.8-27.2 mumole/L for serum, and 10.0-72.5 mumole/L, 25.2-303.6 mumole/L for urine, respectively. Serum free and total hydroxyproline levels in renal osteodystrophy patients on maintenance hemodialysis (N = 71) were significantly higher than in controls (P < 0.0001). This method is superior to the use of HPLC with regard to stability of the color reaction. The measurement of serum free and total hydroxyproline is a useful marker for therapeutic observation of renal osteodystrophy patients.

Chronic Kidney Disease-Mineral and Bone Disorder↗
PubMed1994

Simultaneous automated measurement of serum total CK and CK-MM isoform ratio in serum.

We automated a two-step kinetic procedure for determining serum CK-MM isoform ratio using an immunoinhibition method. By measuring the total CK activity and the residual CK activity (serum CK-MM isoform) remaining after the inhibition by tissue CK-MM isoform specific monoclonal antibody reagent (CK-M01) the CKMM isoform ratio is calculated using the difference between total CK and residual CK activities divided by the residual CK activity. Linearities of total CK and residual CK assays were < or = 7750 U/L and 2,500 U/L, respectively; within-run CVs of isoform ratio (N = 10) were 2.8 and 7.0% (mean 0.14 and 0.60), respectively. The MM3/MM1 isoform ratio obtained with the proposed method (X) correlated well with the results of electrophoretic method (Y) according to the equation: Y = 0.98X-0.3, r = 0.988. The normal reference range of isoform ratios obtained by assaying 1,222 serum samples from healthy subjects was 0.09-0.75. The isoform ratio increased after onset of chest pain, peaking at 2-6 hr thereafter. A mean isoform ratio of 1.86 was obtained with serum sample from 86 patients diagnosed as having an acute myocardial infarction (AMI). This method is accurate and highly sensitive, as the detection and early diagnosis of AMI can be completed in 10 min.

Adolescent↗
PubMed1994

The limiting effect of dichloroacetate on endotoxin-induced liver damage in starved rats.

Dichloroacetate has been shown to have therapeutic effects on sepsis and endotoxin shock and to reduce liver damage in rats intoxicated with ethanol or carbon tetrachloride. In this study, the effect of dichloroacetate on endotoxin hepatitis was investigated. Endotoxin hepatitis was induced by an intraperitoneal coadministration of 50 micrograms/kg lipopolysaccharide from Escherichia coli, and 200 mg/kg D-galactosamine in starved, male Wistar rats. This treatment induced the following changes within 24 hr: an increase in the serum aminotransferase activity, histological alterations of the liver including focal necrosis of liver cells and inflammatory infiltrates, an increase in blood pyruvate and alanine concentrations, and inhibition of starvation ketosis. The intraperitoneal administration of 250 mg/kg dichloroacetate 30 min after the administration of the toxins partially counteracted all of these changes. The administration of dichloroacetate might be useful in coping with hepatic damage as well as lacticemia and cardiovascular depression induced by endotoxins.

Alanine Transaminase↗
PubMed1994

Endotoxin causes early changes in glutathione concentrations in rabbit plasma and liver.

The effects of endotoxin on glutathione concentrations in rabbit plasma and liver were investigated. Lipopolysaccharide (2 mg/kg) from Escherichia coli was administered intravenously to seven male Japanese rabbits. In the liver, the concentrations of reduced glutathione (GSH) started to decrease, and those of oxidized glutathione (GSSG) started to increase 1 hr after the endotoxin administration, resulting in a progressive decline in the hepatic GSH/GSSG ratio. In the arterial plasma, the concentrations of both GSH and GSSG started to increase 1 hr after the endotoxin administration. Because the increase in the concentrations of GSSG was greater than that in the concentrations of GSH, the GSH/GSSG ratio in the plasma decreased as did that in the liver. These changes in glutathione concentrations occurred simultaneously with the increase in serum osmolality, but earlier than the decrease in the arterial ketone body ratio, both of which are thought to be useful markers for liver damage. It was concluded that endotoxin induced an increase in the plasma concentrations of GSH as well as GSSG, and that the changes in plasma glutathione status might be useful markers of endotoxin-induced damage in organs, including the liver.

Animals↗
PubMed1994

Imaging features of maxillary osteoblastoma and its malignant transformation.

We report two cases of osteoblastoma, one of them an unusual case in a 32-year-old woman in whom a maxillary tumor was confidently diagnosed as an osteoblastoma at the time of primary excision and subsequently transformed into an osteosarcoma 7 years after the onset of clinical symptoms. The other patient developed osteosarcoma arising in the maxilla, which was diagnosed 3 years after the primary excision and is very suggestive of malignant transformation in osteoblastoma. We present the radiological features, including computed tomographic and magnetic resonance imaging studies, of this unusual event of transformed tumor and compare imaging features of benign and dedifferentiated counterparts of this rare tumor complex.

Adult↗
PubMed1994

Marked clinical improvement in patients with hepatocellular carcinoma by surgical removal of extended tumor mass in right atrium and pulmonary arteries.

Two patients with advanced hepatocellular carcinoma presented severe exertional dyspnea because of extension of a tumor into the right side of the heart. Removable of the tumor thrombus by open-heart surgery ameliorated the symptoms in each case, but their subsequent courses differed considerably. One patient survived for as long as 8 months thanks to successive multi-disciplinary treatments, whereas the other patient died suddenly 1 month after the surgery. The first patient's hepatocellular carcinoma was more differentiated, and the dyspnea was caused by a low cardiac output due to the intracardiac tumor mass, not by pulmonary embolism as in the second patient's case. We conclude that successive multidisciplinary treatments to control the growth of hepatocellular carcinoma is the most important approach and is indispensable for improving the prognosis.

Adult↗
PubMed1994

Desensitization for sulfasalazine-induced skin rash in a patient with ulcerative colitis.

A patient with ulcerative colitis developed a sulfasalazine-induced skin allergy manifested by a urticaria rash. The patient underwent drug desensitization. The first desensitization, done according to Holdsworth's protocol, resulted in eruption with itching at a dose of 800 mg. The second desensitization, with Das's protocol, failed to reintroduce the drug because of urticarial eruptions. The third challenge, with a more gradual increase in sulfasalazine dose than that used in Holdsworth's protocol, successfully desensitized the patient. The relationship between the drug and various adverse reactions is reviewed and the desensitization to sulfasalazine is discussed.

Aged↗
PubMed1994

Posterior mediastinal endodermal sinus (yolk sac) tumor in a female patient.

Primary endodermal sinus tumor (yolk sac tumor) of the mediastinum is uncommon. Most patients are young and male, and the great majority of tumors are found in the anterior mediastinum. We report a case of primary posterior mediastinal endodermal sinus tumor occurring in a female patient. Surgical excision was performed and three courses of combination chemotherapy were subsequently given. The serum alpha-fetoprotein level returned to normal.

Adolescent↗
PubMed1994

Auditory and colored visual P300 in patients with sequelae of subacute myelo-optico-neuropathy.

To study the cognitive function in 13 patients with sequelae of subacute myelo-optico-neuropathy (SMON), event-related potentials (ERPs) were elicited with tones, clicks, and colored visual stimuli in different tasks. P300 latency was delayed, and P300 amplitude reduced or absent in 5 patients (38%), although neuropsychological assessment for dementia did not differ between patients and 21 age-matched normal controls. P300 and N200 latencies with the tone/tone auditory stimuli and N200 latency with the visual stimuli were significantly delayed, but the latencies of early components (N100 and P200) were not delayed. These findings suggest that SMON patients may have cognitive dysfunction to a slight degree.

Aged↗
PubMed1994

Cognitive event-related potentials and brain magnetic resonance imaging in HTLV-1 associated myelopathy (HAM).

Auditory and visual cognitive event-related potentials (ERPs) were investigated in 14 patients with HTLV-1 associated myelopathy (HAM) and in 36 normal controls. In the HAM patients, the latencies of P300 and N200 by the auditory tone method were significantly delayed, and N100 by the auditory click method was significantly delayed in latency. No abnormal ERP components were observed with visual methods. While these auditory abnormal ERPs were present in the HAM patients, there was no evidence of visual abnormal ERPs. Abnormal lesions on the white matter were evident at magnetic resonance imaging (MRI) in 6 (75%) of 8 patients. There was no correlation between MRI lesions and the abnormalities of ERPs, but there was a significant correlation between bifrontal index on MRI and P300 amplitudes at Cz and Pz sites by auditory tone method. In one patient, atrophy of bilateral parietal lobes was seen on MRI and P300 latencies delayed using various methods. Therefore, the possibility that electrophysiological cognitive impairment in patients with HAM is related to brain atrophy rather than to white matter lesions requires attention.

Adult↗
PubMed1994

Direct inhibitory effect of atrial natriuretic peptide on isolated caecal circular smooth muscle cells via soluble guanylate cyclase.

Atrial natriuretic peptide (ANP) relaxes the vascular smooth muscle via particulate guanylate cyclase. Smooth muscle cells isolated from the caecal circular muscle layer of the guinea pig were used to examine the direct inhibitory effect of ANP on those cells. The role of adenylate cyclase, particulate guanylate cyclase, and soluble guanylate cyclase in the direct inhibitory effect of ANP on contraction of this muscle cell induced by carbachol was investigated. ANP inhibited the contractile response produced by 10(6)M carbachol in a concentration-dependent manner, with an IC50 value of 8nM. An inhibitor of adenylate cyclase (2',5'-dideoxyadenosine) and two inhibitors of particulate guanylate cyclase (HS-142-1, and PMA) had no significant effect on the relaxation produced by ANP. In contrast, an inhibitor of soluble guanylate cyclase (LY83583) significantly and completely inhibited the relaxation produced by ANP. This is the first report demonstrating the direct inhibitory action of ANP on the isolated caecal smooth muscle cells via soluble guanylate cyclase, which differs from the intracellular mechanism responsible for the relaxation of vascular smooth muscle produced by ANP.

Aminoquinolines↗
PubMed1994

Combined high-performance liquid chromatography and radioimmunoassay for ceruletide and its metabolites in dog plasma and urine.

A combined high-performance liquid chromatographic (HPLC) and competitive radioimmunoassay (RIA) method for ceruletide (CLT), an analogue of cholecystokinin-8, was developed to investigate the behaviour of CLT in dogs. Dog plasma samples after administration of CLT were deproteinized and separated by reversed-phase HPLC. Fractions for the HPLC eluate were measured by a RIA and two immunoreactive components were found in dog plasma. One fraction was assumed to be unchanged CLT and the other was the (1-6) fragment peptide of CLT [CLT(1-6)] in accordance with the retention times. For the simultaneous determination by the combined method in dog plasma, the assay recoveries of both compounds were 100% and the values for assay precision (RSD intra-assay) were 8-19% for the CLT assay and 2-17% for the CLT(1-6) peptide assay. The lower limit of quantitation in dog plasma was estimated as 18 pg ml-1 for CLT and 14-20 pg ml-1 for the CLT(1-6) peptide. Diluted urine samples from dogs were directly injected into the HPLC and the immunoreactivities of the fractions were measured. More than 98% immunoreactivity was found at the retention time of CLT(1-6) peptide. Thus only the CLT(1-6) peptide was measured in dog urine by the RIA without HPLC separation. Urine samples could be assayed directly only after dilution 1:20. The assay recovery for urine was 100% and the precision (RSD) was estimated to be < 10%. The lower limit of quantitation for dog urine was 70 pg ml-1. The combined method of HPLC and immunoassay is extremely useful for peptide analyses.

Animals↗