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Biomedical subjects

H Oka

Publications and source records attributed to H Oka.

At least 235 records · Page 13Linked to original sources
PubMed1992

Streptococcal-related antigens stimulate production of IL6 and interferon-gamma by T cells from patients with Behcet's disease.

Greater attention has been recently paid to the role of certain strains of streptococcus as an etiologic agent of Behçet's disease, in which T cell abnormalities are considered to be involved. We therefore examined whether T cells from patients with Behçet's disease might to be stimulated by Streptococcus sanguis-related antigen (RRE KTH-1 antigens). T cells from 17 patients with Behcet's disease, but not those from 13 healthy individuals or from 13 patients with other rheumatic diseases, were stimulated to produce greater amounts of interleukin 6 (IL6) by addition of RRE KTH-1 antigens [stimulation index: 3.96 +/- 0.56 and 1.35 +/- 0.28 or 1.83 +/- 0.43 (mean +/- SEM), respectively]. The IL6 production by T cells required the presence of either fresh or paraformaldehyde-fixed monocytes. The enhancement of T cell IL6 production was not related to the presence of HLA-B51, which has been shown to be frequently associated with Behçet's disease. These results indicate that T cells from patients with Behçet's disease are stimulated by streptococcal antigens to produce IL6 through T cell-monocyte interactions in which binding of the antigens to monocytes, but not necessarily processing of the antigens by monocytes, is involved. Moreover, RRE KTH-1 antigens as well as Escherichia coli-derived antigens also enhanced the production of interferon-gamma by T cells from patients with Behçet's disease. The data thus suggest that T cell hypersensitivity to several bacterial antigens may play a central role in the pathogenesis of Behçet's disease.

Adult↗
PubMed1992

Separation and identification of microcystins in cyanobacteria by frit-fast atom bombardment liquid chromatography/mass spectrometry.

In order to separate and identify microcystins, a new analytical method was developed using a frit probe as an interface for fast atom bombardment mass spectral analysis of high performance liquid chromatographic (HPLC) effluents. Two types of HPLC conditions were designed for separation of standard microcystins RR, YR and LR. The HPLC conditions, for example, methanol:0.01% trifluoroacetic acid = 61:39 (containing 0.8% glycerol) as a mobile phase and 0.5 ml/min as a flow rate, provided a base line separation of standard microcystins RR, YR and LR. The HPLC conditions were also effective for separation of the non-toxic geometrical isomers of microcystins RR and LR. The total ion chromatogram of a mixture of standard microcystins showed excellent correlation with the HPLC separation using a u.v. detector. The method was subsequently applied to analysis of microcystins contained in both a culture strain and a field sample, and the procedure from toxin extraction to identification of microcystins was performed within 1 day. The mass chromatogram monitored at m/z 135 that is always observed with abundance in the FAB mass spectra of the purified microcystins, differentiated between microcystins and other types of compounds. This technique allowed the rapid identification of unknown microcystins without standard samples. Additionally, compounds other than microcystins were also found, which would not be seen by u.v. detection at 238 nm.

Chromatography, High Pressure Liquid↗
PubMed1992

Morphological features of cat thalamo-parietal projection fibers investigated by PHA-L immunohistochemistry and electron microscopy.

Thalamo-parietal fibers originating from the ventroanterior-ventrolateral (VA-VL) complex in the cat were labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) and examined by light and electron microscopy. PHA-L (2.5% aqueous solution) was injected iontophoretically through micropipets with anodal current pulses into the VA-VL complex. PHA-L-labeled terminals were distributed in the lateral and the suprasylvian gyri in the superficial and deep cortical layers. In layer I, horizontal varicose fibers and terminals were conspicuous in the upper one-third and were widely distributed. In the deeper cortical layers (layers III-V), varicose fibers and terminals were detected in moderate numbers. Electron microscopic examination revealed that the labeled terminals formed asymmetrical synapses on the dendritic spines of spiny neurons. These morphological findings appeared to be consistent with our previous intracellular recordings in this cortex.

Animals↗
PubMed1992

Changes of superoxide dismutase activity and ascorbic acid in focal cerebral ischaemia in rats.

Free radical reactions are supposed to cause ischaemic brain damage, and active oxygens can initiate these chains reaction. If active oxygens play important roles in ischaemic brain damage, the activity of superoxide dismutase, scavenger of superoxide anion, is supposed to decrease in ischaemic brain. The reduced form of ascorbic acid also scavenges superoxide anion. In rat middle cerebral artery focal ischaemia, we investigated the changes in superoxide dismutase activity and the concentration of reduced ascorbate up to 48 hours. Middle cerebral artery territory of each cerebral hemisphere was homogenized. The supernatant was divided into two aliquots; one was dialysed to remove ascorbate and the other was not. The enzyme activity of the dialysed specimen from the ischaemic hemisphere did not decrease within 4 h after the arterial occlusion. The activity of the dialysed specimen from the nonischaemic side remained unchanged during the examination. Reduced ascorbate levels in nondialysed samples showed similar changes to the superoxide dismutase activities in the dialysed samples. Our data suggest that ascorbic acid may exert the enzyme activity and that the enzyme activity remains at the normal level in the early phase of ischaemia despite the irreversible ischaemic changes that take place within 4 h after the onset of ischaemia.

Animals↗
PubMed1992

Change of xanthine dehydrogenase and xanthine oxidase activities in rat brain following complete ischaemia.

We studied the activities of xanthine dehydrogenase and xanthine oxidase in rat forebrain after complete ischaemia. Complete ischaemia was induced by decapitation after transcardiac infusion with saline. The activities of xanthine dehydrogenase and xanthine oxidase immediately after ischaemia were 93.3 +/- 38.7 and 18.8 +/- 7.7 microU/mg protein, respectively, and at 24 h after ischaemia were 183.5 +/- 75.1 and 60.8 +/- 15.2 microU/mg protein, respectively. The ratios of xanthine dehydrogenase/xanthine oxidase immediately and 24 h after ischaemia were 5.04 +/- 1.03 and 3.04 +/- 0.99, respectively. These data indicate that xanthine dehydrogenase and xanthine oxidase activities were maintained even 24 h after complete ischaemia. Conversion of xanthine dehydrogenase to xanthine oxidase proceeds slowly during complete ischaemia.

Animals↗
PubMed1992

Development of diabetic complications in a new diabetic strain of rat (WBN/Kob).

The development of ocular, renal, and neural lesions was examined in male diabetic WBN/Kob rats with endoexocrine pancreatic insufficiency. As for the ocular lesions, around 15 months of age, opacity of the lens began to appear. Opacity was first observed in the periphery of the lens, and then increased rapidly in severity, extending concentrically and centripetally, until total cataracts developed. The incidence of cataracts in male rats was gradually increased and reached almost 100% at 24 months of age. As for renal lesions, the 24-h urinary total protein began to increase at about 13 months of age and reached 50-300 mg/24 h at 13-28 month of age, which was significantly higher than in age-matched male Wistar rats (15-25 mg/24 h). Electrophoretic analysis revealed that the urinary protein was almost all albumin. Morphologically, an increased GBM thickness and glomeruli with segmental or global enlargement of mesangial areas were observed. As for neural lesions, a reduction in motor nerve conduction velocity was demonstrated electrophysiologically, and a marked decrease in density and diameter of myelinated fibers in the sciatic nerves were observed morphometrically. In conclusion, the WBN/Kob rat strain with slowly developing but severe lesions associated with pancreatopathy presents a suitable model for human diabetic complications.

Albuminuria↗
PubMed1992

Increase of migration of cultured endothelial cells by angiotensin-converting enzyme inhibitor derived from tuna muscle.

The influence of angiotensin-converting enzyme (ACE) inhibitory octapeptide derived from tuna muscle (tuna AI) on the bovine aorta endothelial cell (BAEC) migration was investigated, as compared with captopril. BAEC migration was quantitated 6 d after release from contact inhibition by a teflon fence assay. The culture grown in the presence of tuna AI (1 and 10 microM) clearly exhibited an increase in migration, compared with the control. The media collected from tuna AI (1 and 10 microM)-stimulated BAECs significantly exhibited the interleukin (IL) -1 activity that was detected by the thymocyte costimulation assay with phytohemagglutinin. Although tuna AI was a weaker ACE inhibitor than captopril, the increasing effect of tuna AI on the migration and the IL-1 generation in BAECs was slightly greater than that of captopril. In quiescent BAECs, tuna AI (1 microM) apparently induced c-myc and platelet derived growth factor (PDGF) A-chain messenger ribonucleic acid (mRNA) expressions within 30 min, which persisted for 6 h. In contrast, captopril induced a very low expression of c-myc mRNA, and had no relation to PDGF A-chain mRNA expression. These results suggest that the increase of BAEC migration by tuna AI, unlike captopril, is likely related to the induction or activation of IL-1, and c-myc and PDGF mRNAs, in addition to the inhibition of the conversion of endogenous angiotensin I to angiotensin II.

Amino Acid Sequence↗
PubMed1992

Preparation of biologically active and site specifically radioiodinated recombinant human insulin-like growth factor-I.

Recombinant human insulin-like growth factor-I (rhIGF-I) was iodinated using a lactoperoxidase-catalyzed labeling method. The labeled products were separated into more than five fractions by ion-paired reverse-phase high performance liquid chromatography (HPLC). A fraction (peak 1), which showed the highest yield and radioactivity, was found to be biologically active in the BALB/c 3T3 cell proliferating system. The site of the iodination was investigated by S-pyridylethylation followed by trypsinization and separation with HPLC using reverse phase columns. From the amino acid analysis of the peaks which were radioactive, the iodination site of peak 1 was revealed to be Tyr-24 and Tyr-60. This is the first report of the biological activity of radioactive peptide hormone with a defined labeled site.

3T3 Cells↗
PubMed1992

Structural characterization of bacitracin components by Frit-fast atom bombardment (FAB) liquid chromatography/mass spectrometry (LC/MS).

The structural characterization of minor components of bacitracin (BC) complex was carried out using a technique of liquid chromatography/mass spectrometry (LC/MS). Satisfactory total ion current chromatogram of BC complex and excellent mass spectra of many components were given by Frit-fast atom bombardment (FAB) LC/MS analytical system, and the structures of 13 minor components could be proposed. The 13 minor components were classified into two groups, bacitracin A (BC-A) related components and bacitracin F (BC-F) related components depending on their common N-terminal moieties. The structures of BC-A related components and BC-F related components were the same as those of BC-A and BC-F, respectively, except that one to three of isoleucine and leucine residues are replaced by valines. The BC-F related components were degradation products of BC-A related components through the same degradation process as that of BC-A.

Amino Acid Sequence↗
PubMed1992

[Prognostic significance of echogenic lesion within small hepatocellular carcinoma].

To evaluate prognostic significance of echogenic lesion within small hepatocellular carcinoma (SHCC, less than or equal to 2 cm in diameter), clinical and pathological findings of 32 cases with SHCC containing echogenic lesion (echogenic SHCC) were compared with those of 55 cases with non-echogenic SHCC. Compared with the non-echogenic SHCC group, the frequency of clinical stage I was significantly higher, and there were significantly more cases with solitary tumor relative to cases with multiple tumors in the echogenic SHCC group. Histologically, the incidence of the HCC composed of well-differentiated tumor cells corresponding to Edmondson's grade I was significantly higher in the echogenic SHCC group than in the non-echogenic SHCC group. Although HCCs tended to become progressively less differentiated with increasing tumor sizes in the both groups, the process of cellular change appeared to proceed more slowly in the echogenic SHCC group. Survival rate after tumor detection was 73% at three years, 56% at five years and 48% at seven years and nine years in the echogenic SHCC group, while it was 46% at three years, 42% at five years and 0% at seven years in the non-echogenic SHCC group. The present results showed that the presence of echogenic lesion within SHCC could be useful prognostic indicator.

Aged↗
PubMed1992

[Motility and mucosal hemodynamics of the lower esophagus after transabdominal esophageal transection for esophageal varices].

Lower esophageal motility and mucosal hemodynamics were investigated in 20 patients who underwent transabdominal esophageal transection for esophageal varices (ET), to evaluate their association with reflux esophagitis and variceal recurrence. In the manometric study with microtransducer catheter, maximum swallowing pressure in the lower esophagus of the patients was significantly lower than that of the healthy controls (20 cases) (26.1 +/- 20.5mmHg vs. 80.0 +/- 10.0mmHg: p < 0.01), while high pressure zone pressure did not differ between the two groups. In comparison between patients with and without esophagitis (E(+) and E(-)), maximum swallowing pressure of E(+) was statistically lower than that of E(-) (12.4 +/- 18.7mmHg vs. 31.0 +/- 19.1mmHg: p < 0.05). In the hemodynamic study by reflectance spectrophotometry, the index of esophageal mucosal blood volume (IHb) and the index of oxygen saturation of hemoglobin (ISo2) of E(+) and E(-) were no different from those in the patients with non-operated esophageal varices (10 cases). Although there was no correlation between the recurrence of RC-sign and mucosal microcirculation, the patients with larger varices tended to have a higher IHb and a patients with F1-varices had significantly lower ISo2 than the patients without varices. This study indicated that the poor clearance ability after ET may lead to reflux esophagitis and the patients with variceal recurrence had the congested mucosal microcirculation, compared to those without variceal recurrence.

Adult↗
PubMed1992

[A case of adult onset hypophosphatemic vitamin D resistant osteomalacia].

A case of adult onset hypophosphatemic vitamin D resistant osteomalacia is described. A 40-year-old female who complained of thorax and lumbar pain and gait disturbance was admitted to our hospital on 7 November, 1988. The patient had hypophosphatemia with normal plasma calcium, parathyroid hormone and 25-hydroxy vitamin D3 concentrations, but had decreased tubular reabsorption of phosphate and decreased plasma 1, 25-dihydroxy vitamin D3 concentrations. The iliac crest bone biopsy showed osteomalacic changes. The 99mTc-MDP bone scintigram showed evidence of increased bone turnover with raised plasma alkaline phosphatase concentrations. After treatment with oral 1 alpha-hydroxy vitamin D3 (3-6 micrograms/day) and intravenous or oral phosphate supplement (0.47-1.74g/day), the subjective and clinical findings improved.

Adult↗
PubMed1992

[Establishment of EGF, EGF-R and FN-R positive human adenocarcinoma cell line (GAC-1)].

A human adenocarcinoma cell line designated as GAC-1, was established from ascites of the 56-year old male patient with rapidly progressive gastric cancer. The doubling time was about 18.5 hours in vitro, and cell cycle analysis using flow cytometry showed marked increase of S phase (46.1%). Immunohistochemical demonstration of GAC-1 cells revealed positive staining of TGF-alpha, EGF, EGF-R, FN-R, laminin and negative staining of fibronectin. Histogram of them indicated aneuploidy with modal number 57 and they formed tumors in nude mice.

Adenocarcinoma↗
PubMed1992

Therapeutic efficacy of latoconazole in formulations of clinical use on experimental dermatophytosis in guinea pigs.

Therapeutic efficacy of clinical dosage forms of latoconazole (NND-318, CAS 101530-10-3), related compound of ketene dithioacetals with an imidazole ring, was examined on two experimental tinea models: a recently developed tinea pedis model and a conventional tinea corporis model in guinea pigs. The efficacy of the dosage forms was estimated on the basis of the rate of fungus-positive skin cultures and/or the score of skin lesions, and was compared to the other antifungal agents, bifonazole, clotrimazole and tolnaftate. While these reference agents exhibited curative effect on the tinea corporis model, the tinea pedis model was considerably resistant to the therapeutic treatment of the agents. The cream preparation and solution of lactoconazole at concentrations of more than 0.25% were highly effective in either tinea models, and at concentrations of more than 1%, lactoconazole achieved complete mycological cure. These results suggest that 1% of lactonazole is an optimal concentration for clinical use.

Animals↗
PubMed1992

[Diagnostic accuracy of coronary artery lesion by 99mTc-MIBI exercise myocardial scintigraphy--containing the utility of simultaneous assessment of left ventricular function].

To determine whether technetium-99m hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) myocardial scintigraphy is a superior method in the detection of coronary artery disease, exercise and rest 99mTc-MIBI planar and SPECT scintigraphy were performed on 27 patients with coronary artery disease. When 99mTc-MIBI (555 MBq (15 mCi)) was injected, first-pass radionuclide angiography (FPRNA) was simultaneously performed by a new mobile multicrystal gamma camera (SIM-400), and LV function (LVEF) was evaluated quantitatively. Visual semiquantitative detection of coronary lesions using 99mTc-MIBI images showed superior accuracy to that obtained using 201TlCl images. 99mTc-MIBI SPECT images were particularly useful in diagnosing LCX and RCA lesions. Moreover, the simultaneous assessment of perfusion and left ventricular function by 99mTc-MIBI FPRNA proved to be useful in the diagnosis of multi-vessel disease. In summary, 99mTc-MIBI SPECT scintigraphy with simultaneous assessment of left ventricular function showed better diagnostic accuracy than 201TlCl myocardial scintigraphy.

Aged↗
PubMed1992

[Diagnostic utility of myocardial imaging using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid in ischemic heart disease].

We evaluated the myocardial metabolism in the acute and subacute phases of myocardial infarction or unstable angina using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid (BMIPP). We then compared those findings with (1) myocardial perfusion images obtained with 201TlCl and (2) the regional and global left ventricular function determined by left ventriculography. Thirty-one patients were examined, consisting of 16 with acute myocardial infarction (6.8 +/- 2.6 days after onset), 8 with subacute myocardial infarction (35 +/- 3.0 days after onset) and 7 with unstable angina. The BMIPP images showed a larger uptake-defect than 201TlCl images in the patients in the acute or subacute phase of myocardial infarction. This finding was especially remarkable in the acute phase after successful coronary revascularization therapy. Moreover, in such cases, the myocardial BMIPP uptake improved to the same degree as 201TlCl one month later. The decrease in myocardial uptake of BMIPP agreed well with the decrease in regional wall motion in the acute and subacute phases of myocardial infarction. In contrast, the myocardial perfusion of 201TlCl did not always agree with the regional wall motion in stunned or hibernating myocardium, where BMIPP showed an uptake-defect in the acute phase but improved in the subacute phase. Thus, BMIPP is surmised to be able to depict fatty acid metabolism in in vivo myocardial imaging.

Adult↗
PubMed1992

[Intramedullary neurofibroma in the cervical spinal cord; a case report].

A 62-year-old woman was admitted complaining of clumsiness in both hands. On neurological examination, bilateral hand muscles were weak, both legs were spastic and hyperreflexic, all the extremities were hypoesthetic. Urological examination revealed detruser sphincter dyssynergia. Spinal CT scan demonstrated an iso density mass lesion in the cervical spinal cord, and it was markedly enhanced. On MRI, it was also markedly enhanced by Gd-DTPA. The operative finding was that an oval shaped tumor was buried in the spinal cord and was totally removed. Its histological diagnosis was neurofibroma. Intramedullary neurofibroma is rare and only 18 cases have been reported. In this case the tumor seemed to have arisen at the root entry zone and to have grown sub-pially.

Female↗