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Biomedical subjects

S Ohkawa

Publications and source records attributed to S Ohkawa.

At least 73 records · Page 4Linked to original sources
PubMed1995

Patients with ultrasonic coarse-nodular cirrhosis who are anti-hepatitis C virus-positive are at high risk for hepatocellular carcinoma.

BACKGROUND: The relationship between echosonographic patterns of patients with cirrhosis who are antihepatitis C virus (HCV)-positive, the DNA synthesis of hepatocytes, and the risk for HCC were studied. METHODS: Thirty-eight patients with anti-C-100 antibody-positive and Child's grade A posthepatitic cirrhosis were studied. DNA synthesis activity was measured by a bromodeoxyuridine (BrdU, a thymidine analogue)-labeling index (LI), using the BrdU-anti-BrdU in vitro method, and the patients were followed prospectively by frequent liver ultrasonography for 3 years. The ultrasound patterns were classified into fine, coarse, and coarse-nodular (CN) patterns, and the reproducibility of the classification in practical use also was confirmed. RESULTS: Of the 21 patients with high DNA synthesizing cirrhosis (BrdU LI > or = 1.5%), 10 (48%) showed coarse-nodular, 5 (24%) coarse, and 6 (29%) fine pattern in ultrasonography. Conversely, of the 17 patients with low DNA synthesizing LC (BrdU LI < 1.5%), only 1 (6%) showed coarse-nodular, 2 (12%) coarse, and 14 (82%) fine pattern. A significant relationship was found between the two groups of BrdU LI and ultrasound imaging patterns (P < 0.05). The incidence of CN pattern was significantly higher (P < 0.01) in the high DNA synthesizing group than in low DNA synthesizing group. Of the 11 patients with CN pattern by ultrasound imaging, 10 (91%) were in the high DNA synthesizing group, and 9 (82%) developed HCC during the follow-up period, compared with 3 of 7 (43%) with coarse, and only one of 20 (5%) with fine pattern developed HCC. The incidence of HCC was significantly higher (P < 0.01) in patients with a CN cirrhosis pattern than in those with a fine pattern. CONCLUSIONS: In patients with cirrhosis who are anti-HCV-positive, the CN pattern by ultrasound imaging indicates increased DNA synthesis of hepatocytes and a high risk for developing HCC.

Adult↗
PubMed1995

Clinicopathologic characteristics of elderly patients with persistent ST segment elevation and inverted T waves: evidence of insidious or healed myocarditis?

OBJECTIVES: We sought to clarify the clinicopathologic characteristics of insidious or healed myocarditis in the elderly. BACKGROUND: Myocarditis is the cause of unexplained congestive heart failure and dilated cardiomyopathy. However, acute myocarditis of the Fiedler type is rare, and the incidence and implication of insidious or healed myocarditis in the elderly are not yet known. METHODS: In an autopsy study of 3,000 patients aged > or = 60 years, there were 12 (0.4%) with insidious or healed myocarditis, showing extensive and circumferential fibrosis and scattered lymphocytic infiltration of both ventricular walls without acute necrosis of the myocardial fibers. RESULTS: Unexplained congestive heart failure was found in seven cases. In all cases, electrocardiography had demonstrated upward elevation of the ST segment and inverted T waves for durations ranging from 1 month to 12.7 years (mean 5.7 years). Mean (+/- SD) heart weight was 338 +/- 81 g (range 220 to 470). In nine cases, fibrous lesions, which were scattered but extensive and circumferential, were located in the subepicardial and middle layers of the left ventricle. In the remaining three cases, the fibrous lesions were located predominantly in the subepicardial and middle layers, but the subendocardial layer was also locally involved. Fibrous lesions of the right ventricle were predominant in the subepicardial layer and involved the subendocardial layer in four cases. Scattered lymphocytic infiltration was found in the fibrous lesions. CONCLUSIONS: In more than half of the aged cases with insidious or healed myocarditis, unexplained congestive heart failure was also present. Fibrous lesions due to myocarditis were located predominantly in the subepicardial and middle layers and led to persistent upward elevation of the ST segment and inverted T waves.

Aged↗
PubMed1995

Analysis of envelope glycoprotein-specific antibodies from SIV-infected and gp110-immunized monkeys in ACC and ADCC assays.

Sera collected from SIV-infected or recombinant glycoprotein-immunized monkeys were characterized for antibodies participating in antibody-complement-mediated cytolysis (ACC) and antibody-dependent cellular cytolysis (ADCC) in terms of their IgG subclass and epitope specificity. In a competitive inhibition ELISA, gp110-specific antibody reactivity with nondenatured rgp110 was blocked completely by soluble homologous rgp110 and partially inhibited by heterologous rgp110, suggesting cross-reactivity between viral strains. However, only partial inhibition was observed with denatured recombinant gp140 (rgp140) in selected monkeys, indicating that the majority of gp110-specific antibodies recognized conformational epitopes. ACC activity against recombinant vaccinia-infected, envelope-expressing targets was found in sera from both infected and immunized monkeys, whereas ADCC activity was observed only in sera from infected monkeys. ACC was blocked with denatured rgp140 as well as nondenatured rgp110, indicating that ACC-mediating antibodies recognized mainly linear epitopes. In contrast, rgp140 did not compete as effectively as rgp110 in the ADCC assay, indicating that the majority of ADCC antibodies recognized conformational epitopes. Competitive inhibition using three peptide fragments of gp110 indicated that epitopes recognized by ACC antibodies lie within amino acid residues 214-471, a region that spans V3, whereas ADCC-reactive epitopes lie between amino acid residues 52 and 214 at the N-terminal end of gp110. Column chromatography of rhesus IgG resulted in three subclass-enriched fractions, designated IgG-I, IgG-II, and IgG-III. IgG-I, but not IgG-II or IgG-III, from both infected and immunized monkeys mediated ACC, whereas IgG-I and IgG-II from infected monkeys mediated ADCC.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

An autopsy case of incomplete left atrial rupture following left atrial infarction associated with left ventricular myocardial infarction.

We report a 78-year-old woman with incomplete left atrial rupture following left atrial infarction associated with left ventricular myocardial infarction. An autopsy revealed a hemopericardium. A large hematoma was observed in the posterior wall of the left atrium and a few small tears were found on the same wall. Near its origin, the left circumflex artery was severely sclerotic and completely occluded by fresh thrombus. Histologic examination revealed that large intramural hematoma longitudinally dissected the inner third of the posterior wall of the left atrium, and transversely dissected through the necrotic tissue to the pericardial sac to result in rupture. Coagulation necrosis and intramyocardial hemorrhage were also observed throughout the entire left atrium and the postseptolateral wall of the left ventricle.

Aged↗
PubMed1995

[Endoscopic mucosal resection of the stomach using a ligating device (EMRL)--experimental study for the purpose of establishing reliable and safe technique].

We confirmed a new reliable and safe technique for endoscopic mucosal resection of the stomach using a ligating device (EMRL), which was used for endoscopic ligation of esophageal varices. We resected the gastric mucosa by this procedure in 6 mongrel dogs, and examined resected specimens histopathologically. It is concluded that EMRL can take a mucosal specimen 15 x 12mm in size on the average, be performed almost all the site which was previously difficult to resect endoscopically, and the submucosal local injection of physiological saline solution is necessary to perform EMRL. Based on these conclusion, we experimented to establish the safe and reliable technique of the divided mucosal resection, too. EMRL procedure is an easy and valuable treatment modality.

Adenoma↗
PubMed1995

Marked bilateral atrial dilation of unknown cause.

Four elderly women with marked bilateral atrial dilation but no evidence of significant structural or functional cardiac abnormalities other than atrial fibrillation are described. All patients demonstrated severe cardiomegaly on chest radiographs. Three patients have remained in good condition during the follow-up of 6 to 16 years except for occasional edema or pleural effusion, which was easily treated with diuretics and/or digitalis. The other patient had had only one episode of pleural effusion and leg edema at age 90 years before she died of colon cancer at age 100 years.

Aged↗
PubMed1995

[Sequential neuroimaging in a patient with delayed post-hypoxic leukoencephalopathy].

We described a patient with delayed cerebral demyelination following a post-operatively hypoxic encephalopathy. A 65-year-old man, with a history of exposure to the atomic bomb at Hiroshima in 1945, suffered from hypoxia, hypotension and respiratory acidosis and became unresponsive 10 hours after a laminectomy for lumbar disc herniation, in December 1993. Following an emergent resuscitation, the patient had gradually recovered and could walk 2 weeks later. Three weeks after the insult, however, the patient developed an apallic state with frontal lobe signs. Except an increased level of myelin basic protein in the CSF, there were no other abnormal laboratory findings. Brain CTs showed a leukoaraiosis. MRI one month post-operation, demonstrated extensive high signal intensity areas in the cerebral white matter on T2-weighted image, and a gadolinium-enhanced spotty lesion in the right globus pallidus on T1-weighted image. Three months after the operation, the high signal intensity on T2-weighted image became more intensive and extensive, while the enhanced spotty lesion in the globus pallidus disappeared. The corpus callosum and cerebellar white matter were spared throughout the observation. The SPECT using 123I-IMP showed a hypoperfusion in the frontal lobe at 1 month. Three months later, the hypoperfusion areas extended to the whole cerebral and cerebellar cortices, relatively less affected in the motor area and basal ganglia. The patient had improved slightly over the next few months. We speculate that subclinical vulnerability in the white matter secondary to exposure to the atomic bomb, in addition to the incomplete prolonged hypoxia, hypotension and acidosis, caused selective cerebral demyelination in this patient.

Aged↗
PubMed1995

[3D-MR cholangio-angiography].

This report introduces a new 3D-MR cholangioangiography technique using 3D Fast SE MR cholangiography and 3D phase contrast MR angiography for obstructive jaundice. In all eight cases, dilated biliary tracts as well as portal veins were clearly visualized on the same image. This new technique helped to determine the operability and surgical strategy for cases with obstructive jaundice. It also provided anatomical guidance for surgical procedures. This study suggests that this technique may replace the currently used modalities for obstructive jaundice.

Aged↗
PubMed1995

[MR venography using 3D-fast STIR sequence for lower extremities].

Venography of the lower extremities performed by injecting iodinated contrast material requires a complicated technique. Veins of lower-flow-speed such as varices are scarcely outlined by using the time-of-flight MR angiography technique. On the other hand, the 2D fast SE technique has proven itself unsuccessful when used with medium magnetic field MRI equipment in which a very long TR is unavailable. We obtained images of lower extremity veins by using the 3D fast STIR technique and medium magnetic field MRI equipment of 0.5 Tesla. The results were crisp angiographic images of lower-flow-speed veins including varices.

Humans↗
PubMed1995

[Warfarin therapy and chlorella].

Warfarin potassium (warfarin) is one of anticoagulants. Its anticoagulant effect is induced by inhibiting vitamin K in a complex manner. It is used effectively and safely in preventing cerebral embolism of cardiac origin, provided that thrombotest (TT) values is maintained from 10 to 20%. A 75-year-old man with atrial fibrillation and cardiomyopathy had cerebral embolism in the territory of the right middle cerebral artery. Warfarin therapy was started to prevent the recurrence of embolic stroke. TT values had been well controlled until intake of chlorella, but they rose above the therapeutic limit after its intake. There was no evidence of discontinuing warfarin, or taking drugs containing vitamin K or Natto. Chlorella is one of vitamin K-rich foods. Thus, it may inhibit the anticoagulant effect of warfarin.

Aged↗
PubMed1994

Synthesis and delta-opioid receptor antagonist activity of a naltrindole analogue with a regioisomeric indole moiety.

Indolomorphinans 2 and 3, in which the indole moiety is fused to the 7,8-position of the morphinan system, have been synthesized from dihydropseudocodeinone 4 and evaluated for antagonist activity on the mouse vas deferens (MVD) and guinea pig ileum (GPI) preparations. Indolomorphinan 2 was found to be approximately 1/60th as potent as naltrindole 1 in the MVD and an agonist in the GPI preparation. A comparable difference in affinity between 1 and 2 was observed. The methyl analogue 3 was inactive in both preparations. The results of this study support the idea that the regio orientation of the indolic benzene moiety of 1 is optimal for delta-opioid receptor antagonist activity. It is proposed that the proper alignment of the benzene moiety with an address subsite on the delta receptor is critical for potent delta antagonist activity.

Animals↗
PubMed1994

Significance of hepatocellular proliferation in the development of hepatocellular carcinoma from anti-hepatitis C virus-positive cirrhotic patients.

BACKGROUND: There is a hypothesis explaining the pathogenesis of carcinoma that increased proliferation of tissue cells correlates with the development of carcinoma, presumably by increased rate of random mutations and by promotion. In this study, the significance of hepatocellular proliferation in the development of human hepatocellular carcinoma (HCC) from anti-hepatitis C virus (HCV)-positive cirrhotic patients was studied. METHODS: Twenty-eight Child A cirrhotic patients who were anti-HCV (C-100 antibody) positive were studied. At the beginning of the study, the in vitro uptake of bromodeoxyuridine (BrdU, a thymidine analogue) by hepatocytes in biopsied liver specimens was investigated as labeling indices (LIs), and they were divided into high-DNA synthetic (BrdU LI > or = 1.5%) and low-DNA synthetic (BrdU LI < 1.5%) groups. The patients were then surveyed prospectively with frequent ultrasonography (every 3 months) for the development of HCC for 3 years. RESULTS: The mean BrdU LI plus or minus standard deviation for 14 cirrhotic patients with high-DNA synthesis activity (BrdU LI > or = 1.5%) was 2.7 +/- 0.8%, and this was significantly (P < 0.001) higher than that for 14 cirrhotic patients with low-DNA synthesis activity (BrdU LI < 1.5%, 0.5 +/- 0.3%). Nine of 14 (64.3%) of the cirrhotic patients with high-DNA synthesis activity developed HCC in the 3-year period, in contrast to only 2 of 14 (14.3%) of the cirrhotic patients with low-DNA synthesis activity P < 0.05).

Aged↗
PubMed1994

Portal vein aneurysm in the liver associated with multiple vascular malformations.

Portal vein aneurysm (PVA) includes focal dilatation of the portal vein, and was formerly thought to be a rare disease. We report a 46-year-old man with chronic aggressive hepatitis and intrahepatic portal vein aneurysm communicating with the hepatic vein. Hemangiomas in the liver and intracranial arteriovenous malformation (AVM) were also found. To our knowledge, this is the first report of a case of PVA in a patient with congenital intracranial AVM. As the PVA in this patient communicated with the hepatic vein, and as hemangiomas in the liver and intracranial AVM were also present, the pathogenesis in this patient seems to have been congenital anomaly of the vasculature.

Aneurysm↗
PubMed1994

Slow abnormal conduction in the low right atrium: its anatomic basis and relevance to atrial reentry.

To characterize slow abnormal conduction in the low right atrium, which is known to be responsible for atrial flutter, electrophysiologic findings were correlated with anatomic features in a canine model of atrial flutter with ligation of the crista terminalis in the midright atrium. Activation in the low right atrium was mapped with a patch electrode containing 52 bipolar electrodes and a multiplexing system. A particular region in the low right atrium showed atrioventricular node-like electrophysiologic properties, a rate-dependent conduction delay, and Wenckebach periodicity. This area coincided with an area responsible for slow conduction during atrial flutter and unidirectional block at its initiation. Both pilsicainide and E-4031 preferentially blocked conduction in the specific area, leading to the termination of atrial flutter. Although refractoriness could not explain the abnormal conduction, anatomic studies consistently found the specific region to be in or around a thick muscle bundle, that is, the crista terminalis, or a thick pectinate muscle branching from the crista, located perpendicular to the wavefront of the pacing impulse and atrial flutter. These electrophysiologic and anatomic findings suggest that slow abnormal and atrioventricular node-like conduction over a thick muscle bundle, which is a normal anatomic feature of the low right atrium, plays a role in the initiation, maintenance, and termination of atrial reentry.

Animals↗
PubMed1994

Immune responses induced by prototype vaccines for AIDS in rhesus monkeys.

A battery of assay systems was used to profile both humoral and cell-mediated immune responses induced by immunization with candidate vaccines consisting of recombinant simian immunodeficiency virus (SIV) glycoproteins rgp110 (nondenatured) with SAF-M adjuvant (gp110 + SAF-M) or rgp140 (denatured) with Freund's adjuvant (gp140 + FA). All of the monkeys became infected after intravenous challenge. However, 16 days following infection, viral antigenemia was reduced in both groups of vaccinates compared to controls. After 23 days antigenemia in the gp110 + SAF-M group remained at the same level as on day 16, whereas antigenemia in the gp140 + FA group was significantly reduced further than the level observed on day 16. Both vaccines induced blastogenic responses in PBMC cultures stimulated with rgp140, which decreased after repeated immunizations. Both vaccines induced high ELISA titers of IgG antibody against rgp140 that were equivalent to the titers in asymptomatic long-term survivors (LTSs). gp110 +/- SAF-M induced high titers of neutralizing antibody. In contrast, gp140 + FA failed to induce neutralizing antibody, suggesting that the natural conformation of the antigen may be essential for the induction of neutralizing antibody. High titers of antibodies capable of complement-mediated cytolysis (ACC) were induced by gp110 + SAF-M, whereas minimal ACC antibodies were induced by gp140 + FA. In spite of high titers of antibodies by ELISA, neither gp110 + SAF-M nor gp140 + FA vaccines induced detectable levels of antibody capable of antibody dependent cell-mediated cytolysis (ADCC). Detectable amounts of MHC class I-restricted, CD8+ cytotoxic T lymphocytes (CTLs) were not induced in immunized monkeys before challenge. After challenge and infection, antibody responses to glycoprotein (detected by ELISA and ACC) as well as glycoprotein-specific CTLs were induced in gp140 + FA vaccinates at levels higher than in nonimmunized control animals, indicating a priming effect by gp140 + FA immunization. No priming effect for ADCC antibody induction was observed in monkeys vaccinated with either gp110 + SAF-M or gp140 + FA. Rhesus monkey groups immunized with two different SIV envelope vaccines differed regarding potentially protective humoral and cell-mediated immune responses. The physical state of the immunogens, the type of adjuvant used, and/or the immunization protocol apparently affected these responses in both a qualitative and quantitative manner.

AIDS Vaccines↗
PubMed1994

Role of increased DNA synthesis activity of hepatocytes in multicentric hepatocarcinogenesis in residual liver of hepatectomized cirrhotic patients with hepatocellular carcinoma.

To examine whether the marked increase in DNA synthesis of hepatocytes in cirrhotic liver might elicit multicentric hepatocarcinogenesis, we examined the relationship between new development of hepatocellular carcinoma (HCC) and the bromodeoxyuridine (BrdU) labeling index (LI) of hepatocytes in the residual liver of hepatectomized patients with liver cirrhosis (LC) and HCC. Eighteen hepatectomized patients with LC and HCC, whose resected liver revealed neither portal nor hepatic vein invasion by histologic examination, were studied (to exclude cases with intrahepatic metastasis). DNA synthesis activity of hepatocytes from the residual cirrhotic liver was measured by a BrdU/anti-BrdU in vitro method. The incidence of HCC recurrence was studied during a 3-year follow-up period. Among 18 patients, 9 patients had recurrence and 9 did not. The average BrdU LI in the recurrent patients was 2.6 +/- 1.3% and was significantly higher than that in patients without recurrence (1.4 +/- 0.5%, P < 0.05). All five patients who had a BrdU LI of 2.4% or above showed recurrence within 3 years, as compared with 4 of 13 (30.8%) patients with BrdU LI of less than 2.4% (P < 0.05). Our data indicate that abnormally high DNA synthesis in hepatocytes in the background cirrhosis might lead to the development of multicentric carcinogenesis in human cirrhotic liver, and in the residual cirrhotic liver of hepatectomized patients with HCC and LC, it may be a predictor of new development of HCC.

Adult↗