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Biomedical subjects

E Okamoto

Publications and source records attributed to E Okamoto.

At least 91 records · Page 5Linked to original sources
PubMed1997

Topical cooling-assisted hepatic segmentectomy for cirrhotic liver with hepatocellular carcinoma.

BACKGROUND: A safe limit for normothermic consecutive portal triad occlusion in hepatectomy for the cirrhotic liver was believed to be around 30 minutes. Possibly, the occlusion time can be prolonged by cooling the ischemic liver in vivo. We describe the technique of segmentectomy assisted by topical cooling and its usefulness in prolonging the hepatic inflow occlusion time for cirrhotic livers without causing further ischemic injury. STUDY DESIGN: Fifty patients with hepatocellular carcinoma and chronic hepatic disease who underwent right-sided segmentectomy under hemihepatic inflow occlusion were divided into two groups: normothermic (n = 27), and hypothermic with hemihepatic topical cooling using ice slush (n = 23). Segmentectomies were carried out in the same way in both groups, guided by initial enbloc ligation of the corresponding portal pedicles. RESULTS: The mean right hepatic inflow occlusion time was significantly longer in the hypothermic group than in the normothermic group (53 +/- 22 minutes compared with 17 +/- 9.3 minutes). Despite the significant difference in occlusion time, no differences were found in the recovery of hepatic functions and the incidence of postoperative complications between the groups. Intraoperative blood loss was significantly less in the hypothermic group. CONCLUSIONS: The hepatic right-sided partial inflow occlusion time can safely be prolonged to 60 to 90 minutes in the presence of cirrhosis without causing another injury from ischemia and intermittent reperfusion.

Aged↗
PubMed1997

[Survey of sensitivities of clinical isolates to antibacterial agents (annual report)].

Research groups were formed in 20 institutions nationwide to investigate carbapenem resistance of clinical isolates. Activities of various antibacterial agents, principally carbapenems, were tested against clinical isolates collected from these institutions. The broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of 17 antibacterial agents for 1,326 strains of 11 bacterial species isolated at the institutions between October and December 1994. The results are as follows: 1. Carbapenems exhibited strong antibacterial activities against MSSA and Streptococcus pneumoniae. Their activities against Enterococcus faecalis were comparable to that of ABPC. Carbapenems showed low activities against MRSA. 2. OFLX exhibited the greatest antibacterial activity against Haemophilus influenzae, followed by MEPM. Antibacterial activities of the other carbapenems were comparable to those of FMOX, CTM, and ABPC. 3. The carbapenems showed high activities against Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Bacteroides fragilis group. Their activities were greater than those exhibited by other beta-lactam antibacterial agents. The carbapenems also exhibited stronger antibacterial activities against Serratia marcescens than the other beta-lactam antibacterial agents, but some resistant strains were detected. 4. The antibacterial activities of carbapenems against Pseudomonas aeruginosa were comparable to those of CAZ, AZT, AMK.

4-Quinolones↗
PubMed1996

Detection of chromosomal abnormalities in uterine leiomyoma using conventional cytogenetic method and interphase fluorescence in situ hybridization.

Seventy-nine uterine leiomyomas were examined using a conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Nine (17.6%) of 51 tumor samples examined showed chromosomal abnormalities by conventional cytogenetic analysis. Rearrangements of chromosome 12 were detected in two tumors. Other tumors showed abnormalities affecting chromosomes 1, 4, 6, 7, 10, 13, 14, and 22. For FISH, the whole-chromosome painting probe and the D12Z3 probe specific for the centromeric region were used to detect structural and numerical abnormalities of chromosome 12. Of forty-one tumor samples, six showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the tumors with structural aberrations identified by FISH, two had normal karyotypes, two showed structural rearrangements of chromosome 12 cytogenetically, and two could not be analyzed because of an insufficient number of metaphases. There were no correlations between the cytogenetic data and clinical parameters. The results indicate that chromosomal abnormalities are important in the biology of at least some types of uterine leiomyomas, and that FISH is a useful complement to conventional cytogenetic analysis in the study of solid tumors.

Adult↗
PubMed1996

Intrahepatic metastases in hepatocellular carcinoma: the role of the portal vein as an efferent vessel.

The mechanism and pathogenesis of the high frequency of intrahepatic metastasis in hepatocellular carcinoma (HCC) has not yet been elucidated. Two hundred and thirty one tumors (< or = 5 cm in diameter) of resected specimens of HCC were examined for the relationship between mode of tumor spread and tumor size. Efferent vessels in HCC were identified by direct injection of radiopaque material into the tumor in 23 resected liver specimens selected at random from the 231 tumors. The most frequent site for tumor spread in HCC was capsular invasion followed by extracapsular invasion, vascular invasion, and finally intrahepatic metastasis. There was a strong statistical correlation between the presence of intrahepatic metastasis and the frequency of vascular invasion (correlation coefficient = 0.998). Radiopaque material injected directly into 23 resected tumors entered only the portal vein in 17 tumors and into both the portal and hepatic veins in six tumors. In all eight patients with unresectable lesions, radiopaque media injected percutaneously into tumor nodules flowed only into the portal vein. These findings suggest that tumor spread in HCC progresses from capsular invasion to intrahepatic invasion and that the portal vein may act as an efferent tumor vessel.

Adult↗
PubMed1996

Detection of aneuploidy in human spermatozoa using fluorescence in situ hybridization (FISH).

Fluorescence in situ hybridization (FISH) with chromosome specific alpha-satellite DNA probes was used to estimate the rates of aneuploidy of chromosomes 1, 17, 18, X and Y in human ejaculated sperm. Sperm samples were collected from six donors, and biotinylated DNA probes, D1Z5, D17Z1, D18Z1, DXZ1 and DYZ3 were hybridized to interphase sperm which had been pretreated with dithiothreitol to expand their nuclei. A minimum of 3,000 sperm per donor were analyzed. The hybridization efficiency was 99.68% for all the five probes. The frequencies of aneuploidy for chromosomes 1, 17 and 18 were 0.65%, 0.66%, and 0.61%, respectively. For XX- and YY-sperm the frequencies were 0.28% and 0.27%, respectively. To estimate the diploidy and disomy rates, a mixture of D17Z1 and D18Z1 were used as probes, and the frequency of diploid sperm was calculated to be 0.27%. After subtraction of the diploidy rate, the disomy rates for chromosomes 1, 17, and 18 were estimated to be 0.38%, 0.39% and 0.33%, respectively. The proportion of X- and Y-bearing sperm were 49.90% and 49.66%, consistent with an expected 1:1 ratio.

Aneuploidy↗
PubMed1996

Detection of chromosomal abnormalities of chromosome 12 in uterine leiomyoma using fluorescence in situ hybridization.

Fifty uterine leiomyomas were examined using conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Of the 50 tumors, nine were examined using FISH on the non-cultured samples. Two (4.0%) of 50 tumor samples examined showed chromosomal abnormalities of chromosome 12 by the conventional cytogenetic analysis. For FISH, the whole-chromosome painting probe and D12Z3 probe specific for the centromeric region were used. Of the 50 cultured samples, 10 showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the nine non-cultured samples, four showed structural abnormalities of chromosome 12, all of which also showed structural abnormalities of chromosome 12 on the cultured samples. These results indicate that chromosomal abnormalities of chromosome 12 are important in the biology of at least some types of uterine leiomyoma, and that FISH is a useful complement to the conventional cytogenetic analysis in the study of solid tumors.

Chromosome Aberrations↗
PubMed1996

Extrinsic nervous control of retrograde giant contraction during vomiting in conscious dogs.

Neural mechanisms controlling retrograde giant contraction during vomiting were studied in six conscious dogs with implanted strain gauge force transducers. The small intestine was divided into proximal (P), middle (M), and distal (D) segments. These segments were transplanted on intact mesenteric neurovascular pedicles. In three dogs, M and D segments were interchanged (group A). In three dogs, P and M segments were interchanged (group B). Before transplantation, apomorphine-induced vomiting caused retrograde giant contractions, starting from the M segment and rapidly migrating to the stomach. However, in group A, even after recovery of interdigestive migrating contractions migration, retrograde giant contractions during vomiting always originated in the distally interchanged M segment and jumped to the P segment without migration to the D segment. In group B, the retrograde giant contraction always originated in the proximally interchanged M segment and successively occurred in the distally interchanged P segment. We conclude that origination and migration of retrograde giant contractions are extrinsically controlled. These motor events during vomiting are thought to be a specific motor function that does not exist in the lower small intestine, and retrograde giant contraction during vomiting may originate in the mid-small intestine.

Animals↗
PubMed1996

Microwave coagulonecrotic therapy for hepatocellular carcinoma.

The present study reports on the usefulness of microwave coagulonecrotic therapy (MCT) as a treatment option for hepatocellular carcinoma (HCC) with poor hepatic reserve. From June 1992 to March 1995, MCT using a microwave electrode was employed on 8 patients using laparoscopic control and 19 with the open method, and wedge resection (Hx) was applied to the 23 patients. All patients had HCC with poor hepatic reserve. Radiation output was 100 watts with a mean radiation duration of about 30 minutes. The severity of liver dysfunction and the regional characteristics of the tumor (tumor size, multiplicity, portal invasion, tumor depth) were comparable between the MCT and Hx groups. The operative time was significantly shorter for the MCT group than the Hx group. The mean blood loss was 1570 ml in the Hx group but negligible in the MCT group. There was no operative mortality in the MCT group in contrast to 4.3% (1 of 23) in the Hx group. Complications were observed in 11.1% (3 of 27) and 34.8% (8 of 23), respectively, for the MCT and Hx groups. The postoperative total bilirubin had lower values and the start of diet was earlier in the MCT group than the Hx group. The 3-year crude and disease-free survival rates were 86% and 44%, respectively, for patients who underwent MCT, which were comparable to 75% and 14% for those with Hx. MCT can achieve long-term results equivalent to those obtained by wedge resections, but it is less invasive and technically easier. Therefore it can be an alternative option in place of limited resection for HCC with poor hepatic reserve.

Angiography↗
PubMed1996

A prospective randomized trial of the preventive effect of pre-operative transcatheter arterial embolization against recurrence of hepatocellular carcinoma.

To clarify whether pre-operative transcatheter arterial embolization (TAE) improves survival after hepatectomy, a prospective randomized comparative study was done. Of a total of 115 registered patients having solitary hepatocellular carcinoma (HCC) 2 to 5 cm in diameter, 18 (15.7%) were excluded after randomization. As a result, 97 patients were chosen as subjects and divided into two groups: hepatectomy with (group A: n=50) and without (group B: n=47) pre-operative TAE. The period of observation of the patients who survived the surgery was between 4.0 and 6.6 years. The randomization appeared to have provided well-balanced groups of patients and the clinico-pathological characteristics of the two groups were quite similar. The necrotic part of the cancerous lesions, as confirmed by operative specimens, amounted to 74.8+/-33.4% (mean +/-SD) in group A and 6.8+/-7.2% in group B (P<0.01). However, the cancer-free survival rates after hepatectomy in both groups showed little difference (39.1+/-7.0 (%+/-SE) and 31.1+/-0.1, respectively). We speculate that TAE is not effective against such HCC accessory lesions as minute intrahepatic metastasis and tumor thrombus and that pre-operative TAE does not improve post-operative survival.

Adult↗
PubMed1996

Pathologic and radiographic studies of intrahepatic metastasis in hepatocellular carcinoma; the role of efferent vessels.

The efferent vessel of hepatocellular carcinoma (HCC) and the mechanism and pathogenesis of the high frequency of intrahepatic metastasis in HCC has not yet been clarified. Three hundred ninety-three resected specimens of HCC were examined for tumor thrombosis in the portal vein and the hepatic vein: 231 tumors < or = 5 cm in diameter were examined for the relationship between mode of tumor spread and tumor size. Efferent vessels in HCC were identified by direct injection of radiopaque material into the tumor in 23 resected liver specimens and by percutaneous infusion of radiopaque media into tumor nodules in 8 patients. The mode of tumor spread in HCC progressed from capsular invasion to extracapsular invasion, then to vascular invasion, and finally to intrahepatic metastasis. There was a strong statistical correlation between the presence of intrahepatic metastasis and portal vein thrombosis (p < 0.05, R = 0.998). Radiopaque material injected directly into 23 resected tumors entered only the portal vein in 17 tumors and into both the portal and hepatic veins in 6 tumors. In all 8 patients with unresectable lesions, radiopaque media injected percutaneously into tumor nodules flowed only into the portal vein. These findings suggest that intrahepatic invasion by HCC may occur through the portal vein as an efferent tumor vessel.

Aged↗
PubMed1996

Cytotoxicity of 7-ketocholesterol toward cultured rat hepatocytes and the effect of vitamin E.

The effects of 7-ketocholesterol on rat hepatocytes prepared by collagenase perfusion were examined. The viability of cells incubated with 100 microM 7-ketocholesterol was significantly lower than those with cholesterol, although the LDH activity in the cultured medium remained unchanged during the incubation. Hepatocytes treated with 7-ketocholesterol produced large amounts of .NO and O2- in the early stage of incubation. Treatment of the hepatocytes with Carboxy-PTIO, which selectively scavenged .NO, or with L-NMMA, an inhibitor of .NO synthase, increased the cell viability. The addition of 7-ketocholesterol to the culture medium tended to increase the ratio of total sterol to phospholipid of the hepatocytes in a time-dependent manner without changing the content of phospholipid. No lipid peroxidation or oxidation of the cellular SH groups, protein SH and glutathione, was apparent. Vitamin E added 1 h before the addition of 7-ketocholesterol prevented the hepatocytes from cell death by suppressing the incorporation of 7-ketocholesterol into the hepatocytes and by scavenging O2-.

Animals↗
PubMed1996

Evaluation of cardiac sympathetic nervous function by 123I-metaiodobenzylguanidine scintigraphy in insulin-treated non-insulin dependent diabetics with hypoglycemia unawareness.

The association between the lack of adrenergic symptoms during hypoglycemia and myocardial 123I-metaiodobenzylguanidine (MIBG) accumulation was investigated in 12 insulin-treated non-insulin-dependent diabetes mellitus (NIDDM) patients who had no evidence of heart disease. These patients were divided into 2 groups according to the presence (group A) or absence (group B) of adrenergic symptoms during hypoglycemia. Autonomic function tests revealed significantly severe autonomic dysfunction in group B compared to that in group A. Insulin infusion test indicated no significant difference in the catecholamine response between the two groups. 123I-MIBG scintigraphy showed that the heart/mediastinum ratio of MIBG uptake was significantly lower, and scintigraphic defect was greater in group B than in group A. There were no significant differences in the washout rate between the two groups. These results suggested that the lack of adrenergic symptoms during hypoglycemia may be associated with cardiac sympathetic nervous dysfunction in insulin-treated NIDDM patients, and this dysfunction is mainly due to cardiac sympathetic denervation.

3-Iodobenzylguanidine↗
PubMed1996

Diversity of the synthetic-state smooth-muscle cells proliferating in mechanically and hemodynamically injured rabbit arteries.

Vascular smooth muscles contain at least three types of developmentally regulated myosin heavy-chain (MHC) isoforms; SM1, SM2, and SMemb. By investigating the expression of the three MHC isoforms, we previously demonstrated in rabbits that smooth muscles proliferating in the neointima of arterio- and atherosclerotic lesions regain an "embryonic" phenotype. In the present study, we examined if neointimal cells are morphologically similar to embryonal smooth muscles and if dedifferentiation of neointimal smooth muscles is a reversible process. Vascular injury was produced in rabbits either by endothelial cell denudation of the aorta or by poststenotic dilation of the carotid artery. We have demonstrated in this study that the proliferating neointimal cells expressed SM1 and SMemb, but not SM2, indicating smooth muscles of an "embryonic" phenotype. The dedifferentiation of neointimal smooth muscles was found to be reversible; at 4 to 8 weeks after injury, a majority of the cells reexpressed both SM1 and SM2, but not SMemb. By electron microscopy, we have revealed smooth-muscle phenotypes determined by MHC isoforms to correspond to the morphologic phenotypes as an increase in membranous organelles, and a decrease in myofilaments was associated with the reexpression of SMemb. Interestingly, we also found that in the medial wall at 4 to 8 weeks after ballooning injury, a number of SM1-negative cells proliferated rapidly, replacing normal smooth muscles. These cells were negative against SM1 and SM2 but positive for SMemb. These SM1-negative cells contained abundant membranous organelles and few myofilaments. These cells did not express SM1 or SM2 even after 8 weeks postinjury. We conclude from these results that the proliferating synthetic-type smooth muscles after vascular injury are composed of SM1-positive cells that are morphologically similar to embryonal smooth muscle and that maintain ability to redifferentiate, and SM1-negative cells that contain few myofilaments and remain dedifferentiated.

Age Factors↗
PubMed1996

Intrahepatic metastases in hepatocellular carcinoma: evidence for spread via the portal vein as an efferent vessel.

BACKGROUND: The mechanism and pathogenesis of the high frequency of intrahepatic metastasis in hepatocellular carcinoma (HCC) has not yet been elucidated. METHODS: Two hundred thirty-one tumors ( < or = 5 cm in diameter) of resected specimens of HCC were examined for the relationship between mode of tumor spread and tumor size. Efferent vessels in HCC were identified by direct injection of radiopaque material into the tumor in 23 resected liver specimens selected from the 231 tumors. RESULTS: The most frequent site for tumor spread in HCC was capsular invasion followed by extracapsular invasion, vascular invasion, and finally intrahepatic metastasis. Radiopaque material injected directly into 23 resected tumors entered the portal vein in only 17 tumors and entered into both the portal and hepatic veins in six tumors. CONCLUSIONS: These findings suggest that tumor spread in HCC progresses from capsular invasion to intrahepatic invasion and that the portal vein may act as an efferent tumor vessel.

Adult↗