Biomedical subjects

S Ishiguro

Publications and source records attributed to S Ishiguro.

At least 127 records · Page 7Linked to original sources

PubMed1997

Quantitative scintigraphic analysis of 123I-MIBG by polar map in patients with dilated cardiomyopathy.

To evaluate sympathetic dysfunction of the heart, one of the factors responsible for heart failure in patients with dilated cardiomyopathy (DCM), we performed 123I-metaiodobenzylguanidine (123I-MIBG) myocardial single photon emission tomography (SPET) in 22 cases of DCM. There were significant relationships between severity scores and defect scores for the early and delayed images. When the data acquired by 123I-MIBG myocardial SPET were compared with left ventricular function, the extent score (r = -0.754, P < 0.01) and severity score (r = 0.693, P < 0.01) for the early images were both significantly correlated with left ventricular ejection fraction (LVEF). For the delayed images also, a good correlation was obtained between LVEF and extent score (r = -0.704, P < 0.01) and between LVEF and severity score (r = -0.801, P < 0.01). the washout rate for the entire left ventricle, calculated from the early and delayed images, also correlated with LVEF (r = -0.643, P < 0.01). Since the 123I-MIBG defect on the early images was shown to be significantly related to left ventricular function, a decrease in neuronal uptake at sympathetic nerve endings appears in the main to account for the 123I-MIBG defect on the early images. The regional washout rate was increased compared to that in the control group (P < 0.01). It was particularly high in the inferior wall, suggesting that acceleration of turnover and poor retention in the area of the 123I-MIBG defect on the early images and then the entire left ventricle was strongly associated with the 123I-MIBG defect on the delayed images. Our results suggest that 123I-MIBG myocardial SPET may be useful in determining the severity of DCM.

3-Iodobenzylguanidine↗

PubMed1997

Expression of carbohydrate antigen sialyl Le(a): a new functional prognostic factor in gastric cancer.

PURPOSE: The prognostic value of the altered expression of carbohydrate antigens sialyl Le(a) (sLe(a)) and sialyl Le(x) (sLe(x)), which have been implicated as functional ligands in heterotypic-cell-adhesion systems in the multistep process of tumor metastasis, were evaluated. PATIENTS AND METHODS: The level of expression of sLe(a) and sLe(x) antigens was examined immunohistochemically in paraffin-embedded tumor samples from 137 patients who underwent resection for gastric cancer. Correlation between the antigens' expression, various established clinicopathologic factors, and prognosis were studied by univariate and multivariate analysis. RESULTS: Tumors that were positive for the sLe(a) antigen were significantly more likely to be large (P = .035), to be localized at the proximal third of the stomach (P = .018), to have an infiltrate appearance (P = .013), to have an invasive mode both in depth of invasion (P = .028) and in lymphatic invasion (P = .002), and to be classified as late stage (P = .011) than those that were negative for sLe(a), whereas the sLe(x) antigen status was not correlated with any clinicopathologic factors. The overall survival of patients with an sLe(a)-antigen-positive tumor was significantly poorer than that of those with an sLe(a)-antigen-negative tumor (P = .0001). Survival within each pathologic stage differed also (stage I, P = .030; stage II, P = .046; stage III, P = .026, respectively). A Cox regression analysis with multiple covariates showed that positive sLe(a) antigen status was an independent prognostic factor for a worse outcome in patients with gastric cancer. According to the mode of recurrence, increased sLe(a) antigen expression significantly affected both peritoneal dissemination and liver metastasis. CONCLUSION: Increased expression of the sLe(a) antigen may serve as a potent prognostic indicator for recurrence in patients with gastric cancer. Careful follow-up and intensive therapy are required for patients with an sLe(a)-antigen-positive gastric cancer.

Adenocarcinoma↗

PubMed1997

Identification of canine calicivirus capsid protein and its immunoreactivity in western blotting.

A canine calicivirus (CaCV) isolated in Japan, designated as CaCV No. 48 strain, was propagated in MDCK cells and purified by CsCl equilibrium gradient centrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the purified samples revealed the presence of only one major species of viral protein of about 60 kilodaltons after Coomassie staining. The same band, presumably that of the capsid protein, was detected by western blotting using a mouse hyperimmune serum. This capsid protein was synthesized in MDCK cells as early as 2 hr post-inoculation. Experimental infection of dogs resulted in the production of anti-CaCV antibodies which were detected by microneutralization test and western blotting. Likewise, serosurvey revealed not only the presence of neutralizing antibodies but also reactivity of the field sera against the capsid protein of the purified virus. These results indicate that the capsid protein of CaCV No. 48 strain is immunogenic and could be detected by antibodies in western blotting.

Animals↗

PubMed1997

[Surgical treatment of aortic valve regurgitation due to nonpenetrating trauma of the chest--a case report and review of the literature in Japan].

A case report and a literature review of the patients in Japan who underwent surgical treatment of an aortic valve regurgitation due to nonpenetrating chest trauma are presented. A 70-year-old man was admitted to our hospital with multiple trauma, including fracture of sternum, caused by traffic accident. After treatment of respiratory and circulatory failure, he was found to have aortic regurgitation and subsequent congestive heart failure. The aortic valve replacement was performed and his postoperative course was good. The tear of aortic valve was detected in the noncoronary cusp, and the size of the tear was 4 mm. The aortic valve was not recognized the findings of inflammatory or rheumatic changes. Before this case, 15 cases were operated in Japan with the diagnosis of traumatic aortic regurgitation. We reviewed them in the table.

Accidents, Traffic↗

PubMed1997

Ex vivo study of the effects of dietary magnesium deficiency on the formation and release of NO from endothelial cells and the sensitivity to NO of smooth muscle cells of thoracic aortas isolated from rats.

We found that the contractile responses to phenylephrine (PE) of isolated endothelium-intact thoracic aortas were enhanced by a nitric oxide (NO) synthase inhibitor, nitro-L-arginine (LNAG). and the magnitude of this enhancement was significantly greater in Mg-deficient than control rats. In this study, we used a sandwich method to evaluate the effects of dietary Mg deficiency on the ability of vascular endothelial cells to form and/or release NO and on the sensitivity to NO of vascular smooth muscle cells. Male Wistar rats were fed a Mg-deficient (10 mg Mg/kg diet) or control (700 mg Mg/kg diet) diet for 30 days. With the sandwich method, when endothelium-denuded thoracic aortas from chow fed rats were used as the assay vessels, and endothelium-intact aortas from control or Mg-deficient rats were used as the NO-donor vessels, neither the aortic contractile responses to PE nor the enhancement by LNAG of these responses in control and Mg-deficient rats differed significantly. When endothelium-denuded thoracic aortas from control or Mg deficient rats were used as the assay vessels and endothelium-intact aortas from chow fed rats were used as NO-donor vessels, LNAG enhanced PE-induced contractions to a significantly greater extent in Mg-deficient than control rats. Furthermore, sodium nitroprusside (a NO donor) had a greater relaxant effect on endothelium-denuded thoracic aortas isolated from Mg-deficient than control rats. These ex vivo results suggest that dietary Mg deficiency in rats has little effect on the formation and/or release of NO by aortic endothelial cells. but it does appear to increase the sensitivity to NO of aortic smooth muscle cells.

Animals↗

PubMed1997

Ex vivo study of the increased sensitivity to NO of endothelium-denuded thoracic aortas isolated from dietary magnesium-deficient rats.

The mechanisms underlying the enhanced relaxant responses to sodium nitroprusside (SNP) associated with magnesium (Mg) deficiency were examined using endothelium-denuded thoracic aortas isolated from rats with dietary Mg deficiency. This enhancement of SNP-induced relaxation was abolished or depressed in the presence of methylene blue (a guanylate cyclase inhibitor). The relaxant responses to 8-bromo cyclic GMP (8-Br cGMP; a membrane-permeable cGMP) of thoracic aortas isolated from Mg-deficient rats were enhanced like those to SNP. These enhanced relaxant responses were depressed by tetraethylammonium (a non-specific K+ channel blocker). Charybdotoxin, a large conductance Ca2+-activated K+ (K[Ca]) channel blocker, inhibited 8-Br cGMP-induced relaxations of aortas from Mg-deficient and control rats. Apamin, a small conductance K(Ca) channel blocker, inhibited 8-Br cGMP-induced relaxations of aortas from Mg-deficient, but not control rats. The relaxant responses to cromakalim (an ATP-sensitive K+ channel opener) of the two groups were not significantly different. These ex vivo results show that dietary Mg deficiency in rats leads to increased sensitivity to NO of endothelium-denuded thoracic aortas in vitro and K(Ca) channel activation via cGMP may be involved in this enhancement.

Animals↗

PubMed1996

Annual changes in colorectal carcinoma incidence in Japan. Analysis of survey data on incidence in Aomori Prefecture.

BACKGROUND: In recent years, the mortality rate for colorectal carcinoma in Japan has rapidly been increasing, and there are indications that it may surpass that of gastric carcinoma, with colorectal carcinoma fast becoming one of the main targets of cancer treatment in Japan. METHODS: Eight thousand three hundred and eighty-six case records of colorectal carcinoma (4479 males and 3907 females; 4691 colon carcinoma cases and 3695 rectal carcinoma cases), diagnosed over 18 years from 1974 to 1991 in Aomori Prefecture, were analyzed. RESULTS: Age-adjusted incidence for colorectal carcinoma per 100,000 population were 12.6 and 8.7 for males and females, respectively, in 1974. The corresponding rates were 20 and 13.6, respectively, in 1980, and 42.5 and 25.6, respectively, in 1991. Among patients with colon carcinoma, a higher proportion have sigmoid colon carcinoma. The degree of increase in the incidence of sigmoid colon carcinoma was almost the same as that of right-sided colon carcinoma. By birth cohort analysis, among those born in 1934 or earlier, the incidence at the same age was higher in the younger population. CONCLUSION: It is possible that the age-adjusted incidence of colorectal carcinoma in Japan will soon resemble that of the white population in the United States, in a manner similar to that of Japanese-Americans.

Adult↗

PubMed1996

Prognostic significance of Ki67 (MIB1) proliferation index and p53 over-expression in chondrosarcomas.

To investigate the prognostic significance of the Ki67 (MIBI)-proliferation index and p53 over-expression in chondrosarcomas, we retrospectively analyzed a cohort of 29 patients with chondrosarcomas using immunohistochemical assays with MIBI and p53 monoclonal antibodies on formalin-fixed, paraffinembedded tissue samples with microwave preparation. We also assessed 19 patients with benign cartilaginous tumors as a control group. There was a significant positive correlation between MIBI index and tumor grade in chondrosarcomas, while there was no significant difference in the MIBI index between the grade-1 chondrosarcomas and the benign cartilaginous tumors. Patients categorized in the high-MIBI-index group had a significantly lower survival rate than those in the low-index group. Moreover, in analyzing the sub-set of the patients with grade-II chondrosarcomas, it was found that they could be prognostically sub-divided according to MIBI index. The p53 index also significantly correlated with patient survival, and there was significant correlation between the MIBI index and the p53 index. However, in multivariate analysis, only the MIBI index and tumor grade proved to be independent prognostic indicators of chondrosarcomas. These results demonstrate that the MIBI index can be a useful procedure for assessing tumor grade in chondrosarcomas, especially for determining the prognosis of patients with grade-II chondrosarcoma.

Adolescent↗

PubMed1996

Amelioration by Kupffer cell blockade in hepatic damage induced by cold preservation with subsequent plasma-supplemented perfusion.

The effects of Kupffer cell blockade with gadolinium chloride (GdCl3) on hepatic injury in the cold preservation with subsequent perfusion was investigated. The condition of the liver grafts which were cold-preserved in University of Wisconsin solution was evaluated by measuring the uptake rates of indocyanine green and hyaluronic acid (IUR and HUR), two indices of liver damage. Perfusion injuries after cold storage occurred in 24-hr-preserved liver and progressed further in 36-hr-preserved liver. GdCl3 prevented the decrease in IUR and ameliorated perfusion injuries in the 36-hr-preserved liver, although GdCl3 did not inhibit the decrease in HUR. The HURs were remarkably decreased in the livers stored even for 6 hr, for which the cold-preserved livers were quite viable, whereas IURs were significantly decreased in livers stored for 24 hr or more when perfusion injury was apparently developed. These results suggest that the IUR is an indicator of hepatic perfusion injury in preserved livers and that Kupffer cell blockade may be a promising strategy for the prevention of hepatic injury after cold preservation with subsequent perfusion.

Animals↗

PubMed1996

Effects of calcium in continuous cardioplegia on myocardial protection.

The effects of calcium (Ca) on a hyperkalemic cardioplegic solution for continuous cardioplegia were examined in an isolated perfused working rat heart model. The coronary arteries were perfused with a modified Krebs-Henseleit bicarbonate buffer (K-H) solution, containing various concentrations of Ca (0.1, 0.6, 1.2, and 2.5 mmol/l) and a high concentration of potassium (20 mmol/l), for 180 min, after which cardiac arrest was induced at 37 degrees C for 180 min. Cardiac function and creatine kinase (CK) were measured. In the control group, K-H solution was infused in place of the cardioplegic solution, and cardiac arrest was not induced. No significant differences were observed between the groups infused with the K-H solution containing Ca concentrations of 0.6, 1.2, and 2.5 mmol/l in the percent recovery of aortic flow (82.1 +/- 2.9%, 80.6 +/- 2.0%, and 71.5 +/- 3.7% (mean +/- SEM) respectively) or in the recovery of other indices of cardiac function, or in CK leakage. There were also no significant differences in the recovery of cardiac function and CK leakage between these groups and the control group. In the Ca 0.1 mmol/l group, however, the characteristic Ca paradox was observed. These findings suggest that if the Ca concentration in a cardioplegic solution is higher than 0.6 mmol/l during continuous cardioplegia, excellent cardioprotective effects will be achieved.

Animals↗

PubMed1996

The preventive effects of OK432 on endotoxin-induced liver injury: liver protection by the modulation of hepatic macrophage function.

The present study was conducted to clarify whether endotoxin-induced liver injury could be improved by modulating the function of hepatic macrophages using OK432, an immunostimulant derived from Streptococcus. OK432 elevated the capacity of hepatic macrophages to produce superoxide and tumor necrosis factor (TNF), and enhanced the mRNA expression of interleukin-1-alpha, -beta, and TNF-alpha in liver nonparenchymal cells (NPC). However, intravenous (iv) preadministration of OK432 reduced the mRNA expression of TNF-alpha in liver NPC enhanced by the endotoxin injection, decreased the serum level of GOT and lactic dehydrogenase (LDH), and improved the survival rate of endotoxin-injected rats. Histological examination revealed a significant reduction in cell vacuolization and focal necrosis in the livers of the endotoxin-injected rats pretreated with OK432. These results indicate that hepatic macrophages play a crucial role in endotoxin-induced liver injury, and that TNF-alpha is one of the factors most likely to be implicated in the development of endotoxin-induced liver injury. Thus, it is suggested that the administration of OK432 provides liver protection by modulating the responsiveness of hepatic macrophages against endotoxin.

Animals↗

PubMed1996

Pathogenicity and vaccine efficacy of a thymidine kinase-deficient mutant of feline herpesvirus type 1 in cats.

We constructed a recombinant feline herpesvirus type 1 (FHV-1) which was deleted in a defined region (450 bp) within the thymidine kinase (TK) gene (C7301dlTK) [Yokoyama et al. (1995) J Vet Med Sci 57: 709-714]. In this report, we carried out two experiments to assess the pathogenicity and vaccine efficacy of the recombinant C7301dlTK in cats. The first experiment showed that, following multiple inoculation of the recombinant C7301dlTK by intraocular, intranasal and oral routes, the virus was sufficiently attenuated in cats, although a high titer of the virus was recovered from target organs (eye, nose, and mouth). In the second experiment, two intramuscular vaccinations with the recombinant C7301dlTK protected cats to a significant degree against subsequent challenge with the parent FHV-1 strain C7301 at 4 weeks after the last vaccination. These results demonstrate that the recombinant C7301dlTK is effective as a live attenuated vaccine with a clear genetic marker.

Alphaherpesvirinae↗

PubMed1996

Vaccine efficacy of recombinant feline herpesvirus type 1 expressing immunogenic proteins of feline calicivirus in cats.

We previously constructed a recombinant feline herpesvirus type 1 (FHV1), C7301dlTK-Cap, which contains an entire open reading frame encoding the capsid protein of feline calicivirus (FCV) F4 strain in the deleted locus of the thymidine kinase (TK) deficient mutant (C7301dlTK) of FHV1. In this report, we carried out in vivo experiments to assess the vaccine efficacy of the recombinant C7301dlTK-Cap against FCV and FHV1 infections in cats. As a result, two vaccinations with the C7301dlTK-Cap by intraocular, intranasal and oral routes protected cats to a significant degree against subsequent virulent challenges with both parent FCV F4 and FHV1 C7301 strains. The results are applicable for the further development of a new genetically engineered polyvalent vaccine for cats.

Administration, Intranasal↗

PubMed1996

More effective endoscopic resection with a two-channel colonoscope for carcinoid tumors of the rectum.

PURPOSE: Complete resection of small carcinoid tumors of the rectum is difficult with conventional polypectomy, because these tumors are most often located in the submucosal layer of the rectal wall. To completely remove these tumors, we used a two-channel videocolonoscope with which both a grasping forceps and a polypectomy snare could be used simultaneously. We evaluated its clinical usefulness in comparison with one-channel colonoscopic polypectomy. METHODS: At Osaka Medical Center for Cancer and Cardiovascular Diseases, seven carcinoid tumors in seven patients were removed with a one-channel videocolonoscope from 1985 to 1992. In 1993 and 1994, ten tumors in nine patients were removed with a two-channel colonoscope. RESULTS: The rate of complete removal of carcinoid tumors with a two-channel videocolonoscope (9 of 10 tumors, 90 percent) was significantly higher (P < 0.05) than with a one-channel videocolonoscope (2 of 7 tumors, 29 percent). No complications occurred during or after endoscopic resection with a two-channel colonoscope. CONCLUSIONS: Endoscopic resection with a two-channel colonoscope is a useful and safe method for resection of small carcinoid tumors of the rectum.

Carcinoid Tumor↗

PubMed1996

Clinical application of three-dimensional myocardial imaging: evaluation of efficacy of medical treatment on myocardial perfusion.

To investigate the clinical applicability of the three-dimensional (3D) myocardial imaging using a newly developed system (the Application Visualization System-Medical Viewer), thallium-201 myocardial single photon emission computed tomography was performed in 19 patients with previous myocardial infarction before and after treatment with nisoldipine. We have developed a new method for automatically reconstructing 3D imaging for the stereoscopic evaluation of myocardial perfusion. The left ventricular myocardial volume with a radioisotope count > or = 50% of maximum was calculated by using the conventional surface rendering method. With these images, the effect of nisoldipine on myocardial perfusion was assessed and the myocardial volume with a radioisotope count > or = 50% of maximum was compared. In fifteen (88%) of 19 patients, myocardial perfusion increased in the infarct areas after nisoldipine treatment. Nisoldipine significantly increased the myocardial volume with a radioisotope count > or = 50% of maximum from 141 +/- 17 to 153 +/- 18 ml on the stress 3D imagings. These findings indicate that nisoldipine improved myocardial perfusion during exercise. 3D imaging provided stereoscopic assessment of the changes in myocardial perfusion following treatment with nisoldipine and also detected transient enlargement of the left ventricular lumen induced by exercise.

Aged↗

PubMed1996

Clinical features of small hepatocellular carcinomas as assessed by histologic grades.

BACKGROUND: Ninety-seven patients with small hepatocellular carcinomas (HCCs) measuring 3 cm or less in size and three patients with adenomatous hyperplasia who underwent radical hepatic resection were examined in this study. METHODS: The lesions were classified into four groups according to the following histologic grading criteria: group A, adenomatous hyperplasia (n = 3); group B, early HCC (n = 6); group C, well-differentiated HCC (wHCC) (n = 32); and group D, moderately or poorly differentiated HCC (n = 59). The involvement factors that seemed to be important or to characterize the progression of HCC and the survival rates were compared among the four histologic groups. RESULTS: The frequency of patients with tumors larger than 2.0 cm in size and that of patients with 200 or more ng/ml serum alpha-fetoprotein increased with the progression of histologic malignancy. Tumor staining on the angiogram, capsular formation, and extranodular invasion were never seen in groups A and B, but they began to appear in group C and increased remarkably in group D. The 5-year survival rates of the patients in groups B, C, and D were 100%, 60%, and 27%, respectively, and statistically significant differences were seen among them. In comparative evaluation of the group C patients the lesions that showed no tumor staining had no capsule, and those that had no capsule had no extranodular invasion. The 5-year survival rate of patients with wHCC without extranodular invasion (81%) was significantly higher than that of patients with extranodular invasion (35%) (p < 0.05). CONCLUSIONS: It may be recommended to provide the category of wHCC without extranodular invasion for pathologic classification of clinically early HCC (i.e., HCC of high curability).

Aged↗

PubMed1996

Characterization and mapping of Ds-GUS-T-DNA lines for targeted insertional mutagenesis.

The transposition patterns of the Ds-GUS transposon T-DNA in 23 independent single-copy lines have been characterized and the map positions of 10 of them on three of the five Arabidopsis chromosomes are reported. Using overexpressed Activator (Ac) elements as a transposase source, it was found that the primary determinant of transposition frequency is the insertion site of the Ac-T-DNA. Neither the structure of the transposon T-DNA nor, in most cases, its insertion site have a significant effect on transposition frequency. Both the frequency and timing of transposition are influenced by the parent through which the transposon and transposase T-DNAs are transmitted. Overall, nearly 75% of plants in which excision has occurred bear a reinserted element and very short-range transpositions predominate, underlining the advantage of using mapped transposons for insertional mutagenesis.

Arabidopsis↗

PubMed1996

A retinal pigment epithelium-derived cell line from transgenic mouse harboring temperature-sensitive simian virus 40 large T-antigen gene.

We established a retinal pigment epithelium-derived cell line from transgenic mouse harboring temperature-sensitive simian virus 40 T-antigen gene (tsSV40T) and examined its characteristics. We enucleated both eyes from a 2-month-old transgenic mouse and removed the retinal pigment epithelial (RPE) cells and neuroretinal cells. After cloning the RPE cells, we obtained a cell line (RPET). RPET cells grew well at 33 degrees C but not at 37 degrees C, expressing on the temperature-sensitive character of tsSV40T, and maintained characters of RPE cells such as T1-tyrosinase production, phagocytosis of rod outer segments, and presence of cytokeratin, microvilli on the cell surface and lysosome-like granules around the Golgi apparatus in the cytoplasm. Conditioned medium (CM) from a culture of neuroretinal cells harboring tsSV40T was essentially required for growth. The factor(s) in CM was heat-and acid labile, but was resistant to trypsin digestion. In the presence of 3% CM, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) and strong effects on RPET cells, whereas insulin, insulin-like growth factor I (IGF-I), and IGF-II had moderate growth effects. Interestingly, none of these growth factors stimulated the RPET cells in the absence of CM. EHS-Matrix had growth effect, whereas laminin, collagen types I and IV, and fibronectin had no marked growth effects on RPET cells. RPET cells were morphologically changed on a laminin-coated dish. They could not spread on the coated dish, and the majority of the cells floated. But when the floating cells were transferred to non-coated dishes, they immediately attached themselves. These results suggest that RPET cells are a good model for for finding novel growth factor(s) and for investigating the mechanism of cell-laminin attachment.

Animals↗