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Biomedical subjects

S Ohkawa

Publications and source records attributed to S Ohkawa.

At least 127 records · Page 7Linked to original sources
PubMed1992

[A clinicopathologic study of atrial infarction complicating left ventricular posterior myocardial infarction].

Among a series of 400 consecutive autopsy cases we performed a clinicopathologic study of atrial infarction in 46 autopsy-proven cases, which had acute or old left ventricular (LV) myocardial infarction. We used blocks taken from both atrial appendages, the region of the sinus-node, the lateral wall of the right atrium, the posterior wall of the right atrium, and the posterolateral wall of the left atrium. Atrial infarction was identified in 13 (28%) of 46 cases with LV posterior infarction which was caused by lesions of the right coronary artery; 10 cases were right atrial infarction and 3 were both right and left atrial infarction. Among 13 cases in which the acute phase of ventricular infarction could be followed, 3 cases exhibited transient atrial fibrillation. Of these 3 cases, 2 had atrial infarction. The mean stenotic index of the proximal right coronary artery was 4.3/5 in the 13 cases of atrial infarction, 3.2/5 in 17 cases of acute necrosis or scar and 3.1/5 in 16 cases without ischemic atrial lesions. Most of the atrial infarction was found in the right atrium; 10 in the right atrial appendage, 8 in the right atrial lateral wall, 3 in the region of the sinus node and the left atrial posterolateral wall, 2 in the right atrial posterior wall, and one in the left atrial appendage. In conclusion, the incidence of atrial infarction was unexpectedly high (28%) in LV posterior infarction caused by lesions of the proximal right coronary artery, particularly in severe stenosis or obstruction.

Aged↗
PubMed1992

[A clinicopathologic study of morphologic tricuspid valve prolapse in the aged: comparison with color Doppler evaluation].

Similar morphologic abnormalities have often been observed in the leaflets of tricuspid valve in patients with mitral valve prolapse. In the present study, morphologic tricuspid valve prolapse was analyzed in 500 consecutive autopsies of the aged over 60 years (mean 78.5 yrs, 266 men, 234 women). Additionally, the sensitivity and specificity of the color Doppler technique applied before death were assessed in 61 autopsy cases. The results were as follows: 1. The incidence of morphologic tricuspid valve prolapse was 22.2% at autopsy in 500 cases of the aged, however, tricuspid regurgitation had not clinically been detected in any of them. 2. The prolapse of 2- or 3-leaflets was common (78.5%). Among the 3 leaflets, the prolapse was more frequently observed in the anterior or posterior leaflet than in the septal leaflet. Combined tricuspid and mitral valve prolapses were observed in 22 cases (19.8%). 3. Among 61 cases examined by color Doppler echocardiography, autopsy showed that 16 cases had tricuspid valve prolapse and 14 cases tricuspid regurgitant flow signals (87.5%). 4. Regurgitant flow signals were also detected in 4 of 12 morphologically normal cases (33.3%). 5. In autopsy cases of the aged, generally, the incidence of morphologic tricuspid valve prolapse and tricuspid regurgitant flow signal were high, however, hemodynamically significant regurgitation due to prolapse was very rare.

Aged↗
PubMed1991

In vitro uptake of bromodeoxyuridine by human hepatocellular carcinoma and its relation to histopathologic findings and biologic behavior.

The in vitro uptake of bromodeoxyuridine (BrdU) by hepatocellular carcinoma (HCC) cells was studied in 30 hepatectomized patients. Labeling of the nuclei by BrdU expressed as labeling index (LI) was 5.6 +/- 3.2% (mean +/- standard deviation), with a considerable variation from case to case. The mean LI in Grade III to IV cancers (less differentiated, by Edmondson and Steiner's classification, 11.1 +/- 2.1%) was significantly larger (P less than 0.001) than that in Grade I to II cancers (more differentiated, 4.5 +/- 2.0%). Capsule formation was found in all 17 patients except one (94%) with a low DNA synthetic HCC (LI less than 6.0%) compared with seven of 13 (54%) with a high DNA synthetic HCC (LI greater than or equal to 6.0%, P less than 0.02). The 2-year survival rate after surgery was significantly higher (P less than 0.02), and intrahepatic metastasis was significantly less (P less than 0.05) in the former group than in the latter. The BrdU LI of HCC tumors showed a strong correlation with histopathologic findings and the biologic behavior of HCC.

Adult↗
PubMed1991

Calmodulin-independent nitric oxide synthase from rat polymorphonuclear neutrophils.

Recently, the purification of nitric oxide synthase (EC 1.14.23) from rat cerebellum has been reported, and the enzyme is a calmodulin-requiring enzyme (Bredt, D. S., and Snyder, S. H. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 682-685). In this paper, nitric oxide synthase has been purified to near homogeneity from the cytosol fraction of rat polymorphonuclear neutrophils. The purification procedure involves affinity chromatography with adenosine 2',5'-diphosphate-agarose and an anion exchange column, DEAE-Bio-Gel A. On polyacrylamide gel electrophoresis in sodium dodecyl sulfate, the enzyme migrated as a single protein band with Mr = 150,000. The molecular weight was estimated to be 150,000 by gel filtration on a Superose 12 HR 10/30. The purified enzyme was unstable with a half-life of 3 h at pH 7.4 and 4 degrees C. The enzyme activity required the presence of Ca2+, NADPH, FAD, and (6R)-5,6,7,8-tetrahydro-L-biopterin. Calmodulin antagonists (W5, W7, W13, and trifluoperazine dihydrochloride) did not inhibit the enzyme activity, and the addition of calmodulin was also ineffective for the increase in the enzyme activity. The neutrophil enzyme appears to be a calmodulin-independent type of nitric oxide synthase.

Amino Acid Oxidoreductases↗
PubMed1991

Increased uptake of bromodeoxyuridine by hepatocytes from early stage of primary biliary cirrhosis.

The relationship between DNA synthesis activities of hepatocytes in biopsied specimens and liver volume was studied in various stages of primary biliary cirrhosis using an in vitro bromodeoxyuridine (a thymidine analogue)-anti-bromodeoxyuridine reaction and computed tomography. The mean bromodeoxyuridine (+/- SE) labeling index for 10 patients in an early histological stage (stage I, 4, and stage II, 6, 3.4% +/- 0.4%) of primary biliary cirrhosis was 17 times that for 6 control subjects (0.2% +/- 0.1%, P less than 0.001), and was significantly higher than that for 19 female patients with chronic aggressive hepatitis (0.9% +/- 0.2%, P less than 0.001), 14 compensated cirrhotic patients of viral origin (all female, 1.1% +/- 0.3%, P less than 0.01), and 5 patients with stage III primary biliary cirrhosis (0.5% +/- 0.1%, P less than 0.001). The mean (+/- SE) liver volume in the early stage of primary biliary cirrhosis (1225 +/- 40 cm3) was about 1.5 times that in control subjects (835 +/- 42 cm3, P less than 0.001). These results suggest that liver volume has already become large in the early stage of primary biliary cirrhosis perhaps because of markedly increased DNA synthesis in hepatocytes.

Adult↗
PubMed1991

Dual inhibitors of thromboxane A2 synthase and 5-lipoxygenase with scavenging activity of active oxygen species. Synthesis of a novel series of (3-pyridylmethyl)benzoquinone derivatives.

A novel series of (3-pyridylmethyl)benzoquinone derivatives was molecular designed and synthesized for the dual purpose of inhibiting thromboxane A2 and leukotriene biosynthesis enzymes and scavenging active oxygen species (AOS). They were evaluated for inhibition of TXA2 synthase, inhibition of 5-lipoxygenase, and for their scavenging activity of AOS using the thiobarbituric acid method. 2,3,5-Trimethyl-6-(3-pyridylmethyl)-1,4-benzoquinone (24, CV-6504) was the most promising derivative since it showed efficient AOS scavenging activity (inhibition of lipid peroxidation in rat brain homogenates: IC50 = 1.8 x 10(-6) M) as well as potent, specific, and well-balanced inhibitory effects on both enzymes (inhibitory effect on TXA2 synthase in human blood, IC50 = 3.3 x 10(-7) M; inhibitory effect on 5-lipoxygenase in human blood, IC50 = 3.6 x 10(-7) M). In adriamycin-induced proteinuria in a rat model, compound 24 at 10 mg/kg per day (po) suppressed proteinuria by more than 50%. The proteinuria, however, could not be reduced by single administration of an inhibitor specific for thromboxane A2 synthase [(E)-7-phenyl-7-(3-pyridyl)-6-heptenoic acid (2, CV-4151)] or for 5-lipoxygenase [2-(12-hydroxy-5,10-dodecadiynyl)-3,5,6-trimethyl-1,4-benzoquinone (1, AA-861)]. The proteinuria was also not reduced by administration of an AOS scavenger, 2-O-octadecylascorbic acid (4, CV-3611). Triple function compounds such as compound 24 that specifically inhibit both enzymes as well as scavenge AOS possess a variety of pharmacologically beneficial effects.

Animals↗
PubMed1991

Involvement of thromboxane A2, leukotrienes and free radicals in puromycin nephrosis in rats.

Thromboxane A2 (TXA2), leukotrienes (LTs) and free radicals are considered to be possible mediators in the induction of glomerular injury and proteinuria. In this study, we examined the involvement of these three mediators and the protective effect of simultaneous inhibition of all three in puromycin aminonucleoside (PAN) nephrosis in rats. A single intraperitoneal injection of PAN (100 mg/kg) induced massive proteinuria and enhanced production of TXA2 and LTs from arachidonic acid in renal cortical slices and renal glomeruli, and increased malondialdehyde levels in plasma, urine and renal cortex. Oral administration of CV-6504(HCl) (3 to 20 mg/kg/day, for 1 to 2 weeks), a novel treble inhibitor of TXA2 synthetase, 5-lipoxygenase and lipid peroxidation, dose-dependently attenuated PAN-induced proteinuria and the increases in these three mediators. Any single specific inhibitor (CV-4151, a TXA2 synthetase inhibitor; AA-861, a 5-lipoxygenase inhibitor; or CV-3611, a radical scavenger) or a combination of two inhibitors showed no or only a slight antiproteinuric effect, but the combination of all three inhibitors significantly reduced PAN-induced proteinuria. These results suggest that, these three mediators may be involved in the pathogenesis of PAN nephrosis and that CV-6504(HCl), which can simultaneously inhibit all three, may be a useful therapeutic agent for nephrosis.

Animals↗
PubMed1991

Efficacy of SIV/deltaB670 glycoprotein-enriched and glycoprotein-depleted subunit vaccines in protecting against infection and disease in rhesus monkeys.

Immunization with an inactivated whole-virus vaccine is highly effective in preventing lentivirus infection. The viral protein(s) essential to the induction of protective responses, however, have not been identified. To define the role of virion components in the induction of protective immunity, we evaluated the efficacy of glycoprotein-enriched and glycoprotein-depleted simian immunodeficiency virus (SIV) subunit vaccines prepared by lentil-lectin affinity chromatography of gradient-purified virions using the immunization and challenge regimen previously found successful with an inactivated whole-virus vaccine. Infection was determined by successful recovery of virus, the induction of SIV-specific antibody responses, and infection of naive recipients by inoculation with lymph-node-derived lymphocytes from the vaccinates. Immunization with the glycoprotein-enriched preparation prevented infection in two out of four monkeys, whereas the glycoprotein-depleted vaccine failed to prevent infection in all four vaccinates tested. However, the glycoprotein-depleted vaccine appeared to moderate the progression of SIV-induced disease compared with non-immunized infected control monkeys inoculated with the same challenge dose. These data suggest that subunit vaccines containing sufficient quantities of viral glycoproteins can protect against SIV infection, whereas subunit vaccines composed predominantly of viral core proteins cannot. The development of effective vaccines against HIV infection should include studies on the optimum presentation of the viral envelope glycoproteins to produce long-term broadly protective immune responses.

Animals↗
PubMed1991

Evidence of sex difference in DNA synthesis in hepatocellular carcinoma.

To clarify sex differences in DNA synthesis in hepatocellular carcinoma (HCC), bromodeoxyuridine labeling indices (BrdU LI) of HCC cells included in tumor biopsy specimens from 12 consecutive male patients and from 5 consecutive female patients all with liver cirrhosis and HCC were examined using an in vitro labeling technique. The mean BrdU LI +/- SE of HCC from male patients (7.7 +/- 0.8%) was significantly (P less than 0.05) higher than that from female patients (4.4 +/- 1.0%). While 7 of the 12 male HCC patients belonged to the high DNA synthesis group (BrdU LI greater than or equal to 7.0%), none of the 5 female HCC patients showed high DNA synthesis (P less than 0.05). We conclude that DNA synthesis in HCC was higher in males than in females.

Aged↗
PubMed1991

Lack of correlation between P pulmonale and right atrial overload in chronic obstructive airways disease.

The correlation between P pulmonale and right atrial overload in chronic lung disease was studied. Right atrial pressure, pulmonary artery pressure, and cardiac output were measured with a Swan-Ganz catheter in nine patients with chronic lung disease and P pulmonale on the electrocardiogram (P wave amplitude of greater than or equal to 2.5 mm (0.25 mV) in leads II, III, and a VF. The results were compared with those in six patients with an atrial septal defect (left to right shunt greater than or equal to 50%) and six patients with pulmonary hypertension (mean pressure greater than or equal to 30 mm Hg without left sided heart disease). Right atrial volume and wall thickness were measured in 10 cases of P pulmonale among 1000 necropsy cases and compared with 141 normal hearts from the same series. The patients with P pulmonale did not show a significant increase in right atrial or pulmonary artery pressures. None of the patients with an atrial septal defect or pulmonary hypertension had P pulmonale on the electrocardiogram. In the necropsy cases of P pulmonale mean (1 SD) in right atrial volume (32 (12) ml) and wall thickness (1.5 (0.7) mm) were not significantly increased (40 (14) ml and 1.4 (0.5) mm in the normal hearts). There was a significant inverse relation between the presence of P pulmonale and the cardiothoracic ratio. In all the patients with P pulmonale chest x ray showed a low cardiothoracic ratio, a considerably depressed diaphragm, and a pendulous heart. This study showed no correlation between P pulmonale and right atrial overload in chronic lung disease. A more vertical anatomical position of the heart, particularly of the right atrium, seems to be the major factor responsible for generation of P pulmonale in chronic airways disease.

Aged↗
PubMed1991

Reduction of 2,3,5-trimethyl-6-(3-pyridylmethyl)-1,4-benzoquinone by PB-3c cells and biological activity of its hydroquinone.

2,3,5-Trimethyl-6-(3-pyridylmethyl)-1,4-benzoquinone (CV-6504) has inhibitory activities on both thromboxane A2 synthase and 5-lipoxygenase as well as scavenging activity against active oxygen species. The latter two activities are closely related to the quinone moiety, which is reduced to a hydroquinone in the living body. Comparison of these two activities for both the quinone and hydroquinone showed that the hydroquinone form had superior activities. Concerning the reduction mechanism by PB-3c cells we can see that superoxide dismutase (SOD) has no influence on the rate of reduction, but dicumarol almost completely inhibits the reduction at a concentration greater than 1 x 10(-6) M. Therefore, it can be concluded that CV-6504 is reduced mainly by two electron donating enzymes without the intermediary of a semiquinone radical and that the resulting hydroquinone inhibits lipid peroxidation as well as 5-lipoxygenase activity.

Animals↗
PubMed1991

[Systolic anterior motion of the anterior mitral leaflet and/or the chordae tendinae in the elderly].

Systolic anterior motion of the anterior mitral leaflet and asymmetric septal hypertrophy (ASH) are characteristic features of hypertrophic obstructive cardiomyopathy (HOCM) on an echocardiogram. Among 9,670 patients over 60 years old examined by echocardiography from January, 1984 to October, 1990, 55 patients showed systolic anterior motion of the anterior mitral leaflet and/or the chordae tendinae (SAM). We investigated clinical features and morphological features of the left ventricle on an echocardiogram in the 55 patients with SAM. They were classified into three groups according to the degree of SAM. Thirty eight cases (group I) had no mitral and/or chordal-septal contact, 10 (group II) had brief contact (less than 30% on the echocardiographic systole) and 7 (group III) had prolonged contact (greater than or equal to 30%). Ages ranged from 60 to 99 with a mean age of 78.2 years. There were 19 males and 36 females and there was a predominance of females in each group. Thirty five cases had hypertension and 34 left ventricular hypertrophy on electrocardiograms. One case of group I, 3 of group II and 7 of group III had a clinical diagnosis of HOCM. In comparison with each group, the incidence of LVH (SV1 + RV5 greater than or equal to 35 mm) was 52% in group I, 90% in group II and 83% in group III and that of LVH (SV1 + RV5 greater than or equal to 70 mm) was 29%, 20% and 67%, respectively. On echocardiographic examination, the diastolic descent rate of the anterior mitral leaflet in the 3 groups was 36.1 +/- 13.1 mm/sec, 19.4 +/- 13.1 mm/sec and 10.7 +/- 11.8 mm/sec (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Morphological observation of the mitral annulus fibrosus (II)].

In 1986, Hutchins observed a high incidence of the disjunction of the mitral annulus fibrosus in mitral valve prolapse syndrome. However, we could not prove his view in our previous study using one section in each case. In this study, the types of mitral annulus fibrosus were analyzed in plural sections. Autopsy hearts of nine aged cases were used for examination of the mitral annulus fibrosus in five to eight longitudinal sections from the posterolateral wall. The types of the mitral annulus fibrosus were classified as; Type A (the mitral valve attaches to the left ventricle), Type B (the valve attaches to the left atrium), Type C (the atrialis layer of the valve continues to the left atrium, while the fibrosa layer continues to the left ventricle), and type D (mitral annulus calcification). A1-3 and B1-3 are subtypes. In the nine cases there were no consistent patterns in type distributions. All sections showed Type A1 (Case 2), Type A1 to A3 (Case 5), and Type B1 to B3 (Case 8). In other cases, a combination of Type A and B (Case 4, 6, 7, 9), and inclusion of Type C (Case 1) and Type D (Case 3) were found. The location of the middle scallop of the posterior mitral leaflet corresponded to the section of the previous study. Among three cases of Type A in the middle scallop, two showed Type A in every section. Among five cases of Type B in the middle scallop, only one case showed Type B in every section. Other four cases showed various combinations with the other types. A case of Type D in the middle scallop showed also Type B and Type C. The conclusion of this study was that in 1/3 of the cases, the type of the mitral annulus fibrosus was consistent, but in the other 2/3 they were not consistent. In other words, one section is not necessarily representative of the morphology of the mitral annulus fibrosus in each case.

Aged↗
PubMed1990

Changes in retention of various telescope crown assemblies over long-term use.

An investigation was done on the effect of crown height, angle (one-half taper) and number of removals on the retention of telescope crowns. Assemblies of inner and outer crowns were constructed on master dies. Crown heights of 4 mm, 5 mm, and 6 mm were used. Cone angles of 0, 2, 4, and 6 degrees were used for each of the three heights. The inner crowns were fixed to the dies with an adhesive agent. the outer crowns were set over them and placed in a clamp. Separation forces were tested with an Instron machine (Instron Corp., Canton, Mass.). They were measured initially and after numerous 100 insertion/separation cycles up to 1000 cycles and numerous 500 insertion/separation cycles up to 10,000 cycles. The results demonstrated that the cone angle of the inner crown was more important than its height for maximum retention. Retention is rapidly lost after the cone angle exceeds 2 degrees. It was also shown that an accessory device is necessary to maintain retention capabilities after long-term use.

Analysis of Variance↗
PubMed1990

Restricted accumulation of globotriaosylceramide in the hearts of atypical cases of Fabry's disease.

Immunohistochemical and biochemical analyses of several tissues were performed in two unusual cases of Fabry's disease which showed accumulation of globotriaosylceramide (Gal alpha 1-4Gal beta 1-4 Glc-Cer, Gb3Cer) only in the hearts, but no clinical signs of the disease. Immunohistochemical study revealed that the hearts from our cases (cases no. 1 and 2) contained large amounts of anti-Gb3Cer antibody-positive granules in cytoplasms as in typical Fabry's disease. The contents of accumulated Gb3Cer in the hearts from case no. 1, case no. 2, and a typical Fabry's disease case were approximately 100, 340, and 100 times higher than those from normal controls, respectively. While typical Fabry's diseased kidney and liver contained approximately 40 and 50 times higher amounts of Gb3Cer than did controls, no accumulation of Gb3Cer was observed in kidney and liver of our cases. The only exception was a slight increase of Gb3Cer in kidney of case no. 2 (about two times higher than controls), in which epithelial cells of the glomeruli but not of other types of cells were positively stained by anti-Gb3Cer antibody. Case no. 1 kidney and liver were not stained by the antibody. The glomerular endothelium and epithelium, tubular epithelium, smooth muscle of renal arteries, and several hepatocytes were Gb3Cer-positive in the typical Fabry's disease case. The involvements of our cases differed distinctly from the typical Fabry's disease case.

Aged↗