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Biomedical subjects

E Okamoto

Publications and source records attributed to E Okamoto.

At least 109 records · Page 6Linked to original sources
PubMed1996

Interferons modify in vitro proliferation of human bladder transitional cell carcinoma in the presence of doxorubicin and mitomycin C.

PURPOSE: The aim of the present study was to investigate whether interferons with their known antitumor activity modify the response of human bladder carcinoma cells to antitumor drugs. MATERIALS AND METHODS: We investigated the in vitro effect of doxorubicin, mitomycin C and the interferons alpha and gamma on cell proliferation in human bladder carcinoma cell lines as measured by 5-bromo-2'-deoxy-uridine (BrdU) incorporation. RESULTS: Exposure of RT 112 (but not EJ 28) cells for 2 hours to doxorubicin (500 ng./ml.) and mitomycin C (200 ng./ml.) reduced the proliferation rate to 85.9 +/- 3.3% (n = 4) and 89.3 +/- 4.0% (n = 4) of control. Treatment for 2 days with interferon alpha and gamma up to the highest concentration (200 U/ml.) showed no effect. The combination of 100 U/ml. interferon alpha and doxorubicin decreased proliferation significantly. At 50 ng./ml. the proliferation rate was decreased to 88.0 +/- 5.7% of control and at 500 ng./ml. to 67.7 +/- 3.1%. Thus interferon alpha seems to increase the sensitivity of the cells to doxorubicin. Cells treated with 20 ng./ml. mitomycin C after pretreatment with interferon alpha showed a dramatic decrease in cell proliferation (from 98.8 +/- 2.1% to 80.2 +/- 4.0% of control). This decrease was similar in the presence of 200 ng./ml. mitomycin C. Thus mitomycin C seems to render cells more sensitive to the antiproliferative action of interferon alpha. Interferon gamma had only minor effects on the response of the cells to doxorubicin or mitomycin C. CONCLUSIONS: These studies suggest that exposure to interferon alpha increases the efficacy of anticancer drugs in vitro, probably by several mechanisms. Potential consequences of this finding for the therapeutic regime employed for treatment of bladder carcinoma are discussed.

Antineoplastic Agents↗
PubMed1996

A ferrofluidic seal specially designed for rotary blood pumps.

One of the key technologies required for rotary blood pumps is sealing of the motor shaft. A ferrofluidic seal was developed for an axial flow pump. The seal body was composed of a plastic magnet and two pole pieces. This seal was formed by injecting ferrofluid into the gap between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was provided on the pole piece. Sealing pressure of the seal was measured. The sealing pressure was maintained at more than 23.3 kPa (175 mm Hg) for a motor speed up to 11,000 rpm. The specially designed ferrofluidic seal for sealing out liquids is useful for axial flow blood pumps.

Blood Flow Velocity↗
PubMed1996

[Differentiation of hypertrophic cardiomyopathy and hypertensive cardiac hypertrophy using the patterns of interventricular septum hypertrophy].

The patterns of interventricular septal hypertrophy were analyzed on two-dimensional echocardiograms to differentiate hypertrophic cardiomyopathy (HCM) from hypertensive cardiac hypertrophy. The control group comprised 110 patients without cardiovascular disease who were matched for age and gender with the hypertension group. The hypertension group comprised 110 patients with uncomplicated essential hypertension, and the HCM group comprised 32 patients in whom the wall thickness of the interventricular septum was 12 mm or more at the mid-portion and no underlying heart disease responsible for cardiac hypertrophy was detected. The interventricular septal thickness was measured both at the thickest portion within 15 mm distal to the aortoseptal junction (basal portion: B) and at the mid-portion (M) in the end-diastolic image on the left parasternal long-axis tomograms, and the B/M ratio was calculated in each patient. The B/M ratio was 1.07 +/- 0.16 in the control group, 1.19 +/- 0.18 in the hypertension group, and 0.83 +/- 0.12 in the HCM group. Compared with the control group, the B/M ratio was significantly high in the hypertension group (p < 0.05) and significantly low in the HCM group (p < 0.01). These results indicate that hypertrophy of the interventricular septum is dominant at the basal portion in hypertensive patients but at the mid-portion in patients with HCM.

Aged↗
PubMed1995

Clinicopathologic spectrum of resected extraductal mass-forming intrahepatic cholangiocarcinoma.

BACKGROUND: The mode of tumor growth of intrahepatic cholangiocarcinoma (CC) varies considerably from patient to patient. This study describes the clinicopathologic variety of the extraductal mass-forming type of CC. METHODS: Patients with CC characterized by an extraductal mass (n = 26) who underwent hepatectomy from 1976 through 1992 were clinicopathologically classified into three types: Type I (n = 7), no biliary stricture; Type II (n = 13), biliary stricture without jaundice; and Type III (n = 6), biliary stricture with jaundice. RESULTS: Type I included three patients with microductular-trabecular arrangement and behavior reminiscent of hepatocellular carcinoma (high association with chronic liver disease, mild positivity for alpha-fetoprotein [AFP], no lymph node metastasis, but frequent intrahepatic metastasis), in contrast to the other typical cholangiocarcinoma. Hepatolithiasis was associated only with Type II CC: The serum positivity for AFP and carcinoembryonic antigen was much higher in Type I CC, whereas positivity of CA 19-9 was highest in Type III. Involvement of the portal vein, hepatic artery, or hepatic duct was most frequent in Type III CC, which necessitated resection of the extrahepatic bile duct and hepatectomy. CONCLUSION: The clinicopathologic behavior of intrahepatic CC differs considerably according to the presence or absence of stricture of the biliary tree. Thus, CC without biliary stricture behaves more like hepatocellular carcinoma, whereas CC with biliary stricture is more like hilar or extrahepatic bile duct carcinoma.

Adult↗
PubMed1995

Sporadic visceral neuropathy.

We encountered three cases of chronic functional colonic obstruction caused by intramural ganglion cell death. Morphologic and pharmacological studies were performed using resected specimens. The patients included a 59-year-old man, a 72-year-old woman, and a 28-year-old man. Barium enema studies revealed segmental stenosis in their left colon. A mecholyl test was positive in all three cases and was useful in diagnosing this disorder. Histopathologic and cytometric examinations disclosed both degeneration and the disappearance of intramural ganglion cells. The number of muscarinic acetylcholine receptors was observed to increase in the muscle layers of the stenotic portion. In addition, the muscle of the affected region showed hypersensitivity to the muscarinic agonist (oxotremorine). These results seem to suggest that this disease is caused by a noncongenital injury to the intramural ganglion cells while the resulting stenosis is considered to reflect the degeneration of the ganglion cells. The etiology of ganglion cell death still remains to be clarified; however, we propose that patients with this disorder may represent a subset of patients with sporadic visceral neuropathy.

Adult↗
PubMed1995

Are human herpes viruses or measles virus associated with esophageal achalasia?

In order to test the hypothesis that esophageal achalasia may be due to neurotropic viral damage to the esophageal myenteric plexus, esophageal tissue with or without achalasia was analyzed by polymerase chain reaction for the presence of human herpes virus DNA or measles virus RNA. The DNA and RNA were extracted from the esophageal muscle of 12 patients with achalasia and six patients with upper esophageal carcinoma. Peripheral blood mononuclear cells from eight adult volunteers and two samples of umbilical blood mononuclear cells were also used as controls. PCR amplification with a pair of primers specific for herpes simplex type 1 and 2 viruses identified 92-bp fragments in nearly all specimens, including those without achalasia. Each 92-bp fragment was confirmed to be identical to a single herpes simplex virus sequence by automated DNA sequence analysis. No amplification for five other herpes viruses or measles virus was detected. Therefore, a specific viral etiology for achalasia was not identified in this study.

Adult↗
PubMed1995

Effect on muscarinic acetylcholine receptors after experimental neuronal ablation in rat colon.

The etiology of denervation hypersensitivity was studied using a rat model. Degeneration of the myenteric plexus was produced by direct application of 0.1% benzalkonium chloride to the serosal surface of the distal colon. Thirty days later, the treated group was compared with a control group undergoing a sham operation. The treated group showed that the decreased number of ganglion cells of the myenteric plexus on routine stain and acetylcholinesterase staining demonstrated the myenteric plexus in the treated group diminished acetylcholinesterase activity. Methacholine (1%), a muscarinic agonist, increased intraluminal pressure in treated but not control rats. The dose-response curve of colonic muscle strips to oxotremorine showed a shift to the left, indicating greater sensitivity, in the treated bowel, with a 50% effective dose (ED50) of 2.5 x 10(-8) in treated muscle and 2.2 x 10(-7) in controls. Binding studies using [3H]quinuclidinyl benzilate ([3H]QNB) showed that the specific maximal binding (Bmax) for [3H]QNB was greater in treated than in untreated animals (228 +/- 26.1 and 135 +/- 42.9 fmol/mg protein, respectively; P < 0.01), even though the dissociation constants (Kd) were the same (0.398 +/- 0.083 and 0.406 +/- 0.065). These findings show that acquired denervation hypersensitivity in this model is due to an increase in the number of muscarinic acetylcholine receptors.

Animals↗
PubMed1995

Purification of a chitooligosaccharidolytic beta-N-acetylglucosaminidase from Bombyx mori larvae during metamorphosis and the nucleotide sequence of its cDNA.

Three beta-N-acetylglucosaminidase (catalyzing hydrolysis of p-nitrophenyl-beta-D-GlcNAc) were purified from the integument tissue of Bombyx mori larvae during metamorphosis into pupae. The largest enzyme (66 kDa by SDS-PAGE, 126 kDa by gel-filtration chromatography) reacted with chitooligosaccharides to produce GlcNAc. A full-length cDNA encoding this chitooligosaccharidolytic beta-GlcNAcase was isolated. Based on the amino acid sequence deduced from the nucleotide sequence, the pre-beta-GlcNAcase was found to consist of 596 amino acid residues including a characteristic signal peptide of 23 residues and have an M(r) of 68,212. Homoloyg search and limited proteolytic digestion showed that the enzyme has a C-terminal 58-kDa catalytic domain very similar to that of human lysosomal beta-hexosaminidase that is responsible for hydrolyzing gangliosides. Two other enzymes (composed of 58-kDa and 48-kDa polypeptides, respectively) did not hydrolyze chitooligosaccharides, and were not proteolytic fragments from the largest enzyme judged by amino acid sequencing analyses. Natural substrates for the beta-GlcNAcases are unknown.

Acetylglucosamine↗
PubMed1995

Prediction of early development of chronic nonrheumatic atrial fibrillation.

The purpose of this study was to identify predictors of development of chronic nonrheumatic atrial fibrillation within one year of onset, thereby minimizing the risk of embolic complications and death. We retrospectively studied 137 patients with new-onset nonrheumatic atrial fibrillation. Chronic atrial fibrillation developed in 30 patients at the end of one year (chronic group). Atrial fibrillation remained paroxysmal in 107 patients (paroxysmal group). Clinical characteristics, electrocardiograms, and echocardiograms at the time of the onset of atrial fibrillation were compared in the two groups. Patients in the chronic group were significantly older than patients in the paroxysmal group (70.1 +/- 8.2 vs. 62.4 +/- 11.0 years, p < 0.01) and had a significantly higher incidence of congestive heart failure (13% vs. 3%, p < 0.05) and diabetes mellitus (37% vs. 19%, p < 0.05). The chronic group also exhibited higher cardiothoracic ratio (52.0 +/- 5.7% vs. 47.6 +/- 5.0%, p < 0.01), greater f-wave amplitude in lead V1 (1.48 +/- 0.91 vs. 1.06 +/- 0.45 mm, p < 0.05), larger left atrial dimension (41.0 +/- 6.4 vs. 34.2 +/- 7.6 mm, p < 0.01), and lower left ventricular ejection fraction (71.4 +/- 5.6% vs. 75.5 +/- 8.2%, p < 0.05). The presence of four or more of the following seven factors strongly predicted the development of chronic nonrheumatic atrial fibrillation within one year (88% to 100%): age > or = 65 years, congestive heart failure, diabetes mellitus, cardiothoracic ratio > or = 50%, f-wave amplitude > or = 2.0 mm, left atrial dimension > or = 38 mm, and ejection fraction < or = 76%.

Adult↗
PubMed1995

Bilateral arachnoid cysts of the sylvian region in female siblings with glutaric aciduria type I. Report of two cases.

Two sisters, aged 6 and 2 1/2 years, presented with macrocephaly and delayed motor development and were found on computerized tomography to have bilateral arachnoid cysts of the sylvian region. Cystoperitoneal shunting of the larger cysts resulted in considerable neurological improvement in both children. Subsequent screening of the patients' urine for organic acids showed that the two sisters were suffering from glutaric aciduria type I (GA-I). To the best of the authors' knowledge, this is the first report to provide clear radiological and surgical evidence of the association between GA-I and bilateral arachnoid cysts of the sylvian region. The role of the shunting procedure used in these cases is discussed.

Arachnoid Cysts↗
PubMed1995

Response of plasma and tissue endothelin-1 to liver ischemia and its implication in ischemia-reperfusion injury.

This study was designed to investigate the changes in plasma and tissue endothelin-1/endothelin-2 (ET) after liver ischemia and to assess the protective effect of anti-ET 1/ET 2 monoclonal antibody (ET antibody) against ischemia-reperfusion injury. The ET levels in the liver tissue, hepatic venous blood of the ischemic and non-ischemic sides, and in the portal venous blood were measured before and after partial liver ischemia for 1 hour in the adult dog. The ET levels in the liver tissue and hepatic venous blood on the ischemic side increased slightly during ischemia and markedly after reperfusion, whereas those on the nonischemic side showed no significant increases. The ET levels in the portal venous blood peaked at 1 to 3 hours after ischemia, which was significantly higher than the levels in the hepatic venous blood on the ischemic side and which correlated with the portal venous pressure elevated because of the partial liver clamping. The administration of antibody (2 mg/kg, intravenous) before reperfusion resulted in a significant inhibition of the postreperfusion elevations of serum-glutamic-oxaloacetic transaminase (GOT), S-glutamic pyruvic transaminase (GPT), and the indocyanine green (ICG) dye retention rate. In conclusion, ET was produced both in the liver tissue exposed to ischemia and in the vascular endothelium of the portal bed exposed to portal congestion. The ET released from the vascular endothelium, including the liver and the portal bed, was found to be a possible factor of ischemia-reperfusion injury.

Animals↗
PubMed1995

Hepatic resection under in situ hemihepatic hypothermic perfusion with hepatoprotective agents.

Hepatectomy was performed under in situ right lobar hypothermic perfusion combined with hepatoprotective agents in six patients who had hepatocellular carcinoma and coexisting liver disease. Following occlusion of the right hepatic vein and the right portal pedicle, in situ cold perfusion was initiated using chilled Ringer's lactate infused through a cannula placed in the right main portal vein. The right superior segments were resected in a bloodless field. The liver was cooled to 22-26 degrees C for 40 to 80 minutes with no significant changes in systemic hemodynamics or body temperature. Postoperative liver functions showed no marked derangement; the mean peak GPT was 221 U and the mean peak total bilirubin 2.3 mg d/l. Local cooling minimizes the risk of ischemia/reperfusion injury in this very vulnerable population, yet gives the surgeon adequate time to perform a challenging resection in a bloodless field.

Aged↗
PubMed1995

[Legal aspects of health insurance claims and their potential use as a data source for epidemiological research].

Health insurance claims are legal documents for the purpose of billing health care cost and not intended for medical certification. They contain valuable public health data as well as sensitive personal information which must be kept confidential. Conflicts arise between the public interest and the privacy protection when public health researchers attempt to perform studies using health insurance claims. This article examines the legal aspects of health insurance claims and proposes legitimate procedures and forms for using claims data in public health research: researchers should act as "contractors" to perform survey under the auspices of insurers instead of requesting the "disclosure" of the personal information.

Confidentiality↗
PubMed1995

Laparoscopic microwave coagulonecrotic therapy for hepatocellular carcinoma.

The present study reports on the usefulness of laparoscopic microwave coagulonecrotic therapy as a new option in the treatment of hepatocellular carcinoma. Five patients with liver tumors associated with cirrhosis were treated from July 1993 to March 1994 with a microwave electrode (output 100 W, 3 to 4 cm long) devised for laparoscopic use. The tumors, all with diameters less than 3 cm and superficially located, were coagulated for a total radiation period of 20 to 30 min under laparoscopic, intraoperative ultrasonographic control. Postoperative complications were negligible, and laboratory values (glutamate-pyruvate transaminase, bilirubin, prothrombin time, platelet count) returned to preoperative levels within 7 days. Complete necrosis, including the surrounding liver tissue, was confirmed by a follow-up dynamic computed tomography scan during the follow-up period of 6 to 17 months (mean, 13 months). Laparoscopic microwave coagulonecrotic therapy can exert an effect on tumor equivalent to that obtained from a wedge resection but is noninvasive and may represent a new option for unresectable liver cancers.

Aged↗