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Biomedical subjects

Y Goto

Publications and source records attributed to Y Goto.

At least 361 records · Page 20Linked to original sources
PubMed1998

Doppler estimation of portal blood flow after percutaneous transhepatic portal vein embolization.

OBJECTIVE: To elucidate changes in portal blood flow (PBF) after percutaneous transhepatic portal vein embolization and their possible association with hypertrophy of the nonembolized hepatic segments. SUMMARY BACKGROUND DATA: The increase in PBF of the nonembolized hepatic segments after embolization is presumed to trigger hypertrophy of these segments. However, changes in PBF after embolization have not been investigated, and their extent remains unknown. METHODS: The authors prospectively measured PBF velocity, using color Doppler ultrasound, in 21 patients without cirrhosis who underwent embolization of the right portal vein or the right portal vein plus the left medial portal branch. Liver hypertrophy was assessed with a volumetric study using computed tomography. RESULTS: The PBF velocity significantly increased, from 11.1+/-3.6 cm/sec before embolization to 20.1+/-7 cm/sec 1 day after embolization. Subsequently, the velocity gradually decreased, but it remained significantly elevated until postembolization day 14. The volume of the nonembolized segments significantly increased from 370+/-141 cm3 to 488+/- 145 cm3. The hypertrophy rate (cm3/day) of the nonembolized segments after embolization correlated closely with the extent of increase in the PBF velocity, expressed as the velocity on day 1 divided by the velocity before embolization. The hypertrophy rate had a significant correlation with the absolute value of the PBF velocity on day 1, but its correlation coefficient was low. No significant correlations were observed between the hypertrophy rate and other clinical variables. CONCLUSIONS: The hypertrophy rate of nonembolized hepatic segments after embolization is predictable from the extent of the increase in the PBF velocity. This can be estimated easily and noninvasively with Doppler ultrasound 1 day after embolization.

Adult↗
PubMed1998

Childhood bacterial meningitis in Japan.

Haemophilus influenzae type b (Hib) vaccines currently are not used in Japan, but interest in preventing H. influenzae disease by immunization has grown. We performed a retrospective survey for bacterial meningitis in 6 prefectures of Japan. Questionnaires requested the age, sex, clinical outcome and identity of the etiologic organism, if known, of all patients with meningitis younger than 16 years of age who were admitted during calendar year 1994. Of 876 hospitals within the 6 study prefectures, 363 (41.4%) returned a completed questionnaire. There were 1769 cases of meningitis reported, of which 160 (9%) were considered bacterial in origin. H. influenzae was the most common cause of bacterial meningitis, accounting for 68 cases (43%). Sixty-six cases (97%) of H. influenzae meningitis occurred in children 4 years of age or younger, and 27 (40%) occurred in children <1 year of age. Calculated incidence rates based on the population of children 4 years of age or less for each prefecture ranged from 3.4 to 9.9 cases per 100000 (mean, 4.7 cases/100000). H. influenzae is the most common cause of meningitis in Japan, and the estimated incidence rates from this study are very similar to those previously reported from Japan. More comprehensive, prospective surveillance studies will be needed to define better the incidence of Hib meningitis and to aid in making rational decisions regarding the use of Hib vaccination in Japan.

Adolescent↗
PubMed1998

Relationship between glutathione and polyamine metabolism after partial hepatectomy in alcohol-treated rats.

In a liver regeneration inhibiting model after partial hepatectomy in rats, we determined hepatic glutathione concentration and studied its relation with polyamine, an indicator of liver regeneration. Experiment 1: Male ODS rats and Wistar rats as control were maintained with vitamin C-deficient diets for 2 weeks. In the alcohol group, 3 g/kg of ethanol was administered orally 1 hr before partial hepatectomy. Experiment 2: Wistar rats were divided into four groups, according to the presence or absence of alcohol and vitamin E (VE), and a 6-week pair-feeding was done. As for partial hepatectomy, about 70% of the total liver was excised. As a result, in experiment 1, hepatic glutathione levels were significantly decreased by acute alcohol administration in both ODS and Wistar rats, and its level of alcohol administration group of ODS rats was the lowest. Hepatic ornithine decarboxylase activity and putrescine level 4 hr after partial hepatectomy showed almost a similar behavior, being the lowest in the alcohol administration group of ODS rats. In experiment 2, hepatic glutathione level showed no influence by chronic alcohol administration, but was the lowest in the VE-deficient alcohol administration group. Hepatic ODC activity and putrescine level 4 hr after partial hepatectomy showed no influence by chronic alcohol administration, but was the lowest in the VE-deficient alcohol administration group. These results clarified that intrahepatic glutathione levels before partial hepatectomy were decreased in the models in which hepatic ODC activities after surgery were suppressed.

Animals↗
PubMed1998

Succinylcholine-induced fasciculations in denervated rat muscles as measured using 31P-NMR spectroscopy: the effect of pretreatment with dantrolene or vecuronium.

BACKGROUND: We have previously demonstrated by 31P nuclear magnetic resonance (NMR) that succinylcholine (SCh) induces metabolic changes in denervated muscle. To specify those changes, we attempted to inhibit them using two different kinds of drugs, dantrolene and vecuronium. METHODS: Three weeks after unilateral sciatic nerve section, 75 male Wistar rats were randomly assigned to one of the following 5 groups: (1) non-pretreated normal muscle group; (2) non-pretreated denervated muscle group; (3) denervated muscle group pretreated with a low dose of vecuronium (0.02 mg.kg(-1)); (4) denervated muscle group pretreated with a high dose of vecuronium (0.2 mg.kg(-1)); (5) denervated muscle group pretreated with dantrolene (2 mg.kg(-1)). The change of the inorganic phosphate/phosphocreatine (Pi/PCr) ratio of each muscle was measured by 31P-NMR before and after SCh (1 mg.kg(-1)) administration and the corresponding peak amplitude of the electromyograms (EMG) was determined. RESULTS: The high dose of vecuronium totally inhibited SCh-induced fasciculation on EMG (100%-->2%). In this group, though the Pi/PCr ratio significantly increased 10 min after SCh, the peak after 5 min disappeared. The inhibition with dantrolene was about the same order of magnitude as with the low dose of vecuronium (35%:21%). However, the increase in the Pi/PCr only lasted about 10 min, in contrast to the other drugs. CONCLUSION: Our findings indicate that the Pi/PCr increases 5 and 10 min after SCh, respectively, as a result of two different processes. The first peak is caused by an excessive energy consumption in response to excessive muscle contraction. This in turn triggers the second peak, caused by breakdown of glycogen, initiated by an increased Ca2+ concentration.

Animals↗
PubMed1998

Use of systematic biopsy results to predict pathologic stage in patients with clinically localized prostate cancer: a preliminary report.

BACKGROUND: The purpose of this study was to determine the ability of clinical tests to predict advanced pathologic stage (seminal vesicle invasion, pT3c, or pelvic lymph node metastases, pN+). METHODS: T stage, PSA, PSA density, and pathologic features in systematic biopsy specimens were correlated with pathologic stage in 190 consecutive patients with clinically localized (T1-3) prostate cancer detected by systematic needle biopsies and treated with radical prostatectomies. RESULTS: Thirty-three patients (17%) had an advanced pathologic stage cancer (pT3c or pN+). In logistic regression analysis, the total length of cancer in all biopsy cores (P < 0.0005), the percent of poorly-differentiated cancer in each specimen (P< 0.021), and serum PSA (P< 0.028) were the only significant predictors of advanced stage. A model was constructed to predict advanced stage: if the PSA was > or = 6 ng/mL and 4 or more biopsy cores were positive and the total length of cancer in all cores was > or = 20 mm and at least 10% of the cancer was poorly-differentiated, then 14 (93%) of 15 patients had an advanced pathologic stage cancer compared to 11% of the remaining 175 patients (P < 0.0005). CONCLUSION: The pathologic features of cancer in systematic needle biopsy specimens more accurately predicts which patients have advanced stage cancer than standard clinical tests alone.

Aged↗
PubMed1998

Long-term thrombosis after transvenous permanent pacemaker implantation.

To assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis after long-term transvenous permanent pacemaker implantation, venograms were performed in 100 consecutive patients at the elective replacement of the pacemaker. Mean follow-up period after initial transvenous permanent pacemaker implantation was 6.0 years. The venograms demonstrated normal in 77 patients. The remaining 23 venograms showed venous stenosis in 11 patients and total obstruction in 12 patients. Twenty-one of these 23 patients had venous collateral circulation. No difference was found in the incidence of venous abnormalities according to the route of entry, the lead insulation, the total number of the implanted leads, and anticoagulant and antiaggregant drugs. All these patients have remained asymptomatic. In conclusion, the incidence of venous thrombosis after long-term transvenous pacing is 23% and the causes of venous thrombosis may be endothelial trauma and underlying venous stenosis. As this article describes a retrospective limited study, we cannot find the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis formation after transvenous permanent pacemaker implantation. Further prospective study will be needed to assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs.

Aged↗
PubMed1998

Increased plasma adrenomedullin levels in patients with acute myocardial infarction in proportion to the clinical severity.

OBJECTIVES: To investigate the pathophysiological role of adrenomedullin in myocardial infarction. PATIENTS AND DESIGN: Plasma concentrations of adrenomedullin, atrial natriuretic factor, and brain natriuretic peptide were measured by radioimmunoassay in 31 patients with acute myocardial infarction over four weeks, and in 44 normal subjects. RESULTS: In patients with acute myocardial infarction, plasma adrenomedullin reached a peak of (mean (SD) 14.0 (9.0) pmol/l at 24 hours after the onset of symptoms and remained increased at all sampling points except the four week point compared with the value in normal subjects (5.0 (2.0) pmol/l). Adrenomedullin concentrations on admission were higher in patients from Killip class II, III, and IV than class I, and correlated positively with peak plasma creatine kinase and left ventricular end diastolic volume index, and negatively with left ventricular ejection fraction. The values from 12 to 48 hours were negatively correlated with systemic vascular resistance index. During the time course studied, adrenomedullin concentrations were positively correlated with atrial natriuretic factor (r = 0.40, p < 0.001) and brain natriuretic peptide (r = 0.53, p < 0.001). CONCLUSIONS: Plasma adrenomedullin concentrations increased in the acute phase of myocardial infarction in proportion with clinical severity suggesting that adrenomedullin may play an important role in the pathophysiology of myocardial infarction.

Adrenomedullin↗
PubMed1998

Surgical treatment of the coronary artery to pulmonary artery fistulas in adults.

Coronary artery to pulmonary artery fistula (CA-PAF) is a rare congenital anomaly. The purpose of this retrospective study was to analyze 11 adult patients with CA-PAFs treated surgically, and to evaluate the surgical management and long-term results. There were no surgical deaths and all patients survived the follow-up periods (mean 7.2 years). All symptomatic patients improved their New York Heart Association functional class. As surgical correction is safe and effective, with good long-term results, all the patients with CA-PAF in adults can be candidates for surgery to prevent life-threatening complications.

Adult↗
PubMed1998

20-Hz flicker stimulus can isolate the cone function in rat retina.

Cone electroretinograms (ERGs) are typically isolated in humans by flicker stimuli against rod-desensitizing adapting fields. To investigate the manner in which adapting-field luminance affects the cone ERGs, we recorded ERGs in normal albino Sprague-Dawley rats with flicker stimuli presented against adapting fields that ranged in luminance from to 1.75 log cd/m2. A flicker rate of 20 Hz was used to isolate the cone ERGs under all adaptation conditions. We found the amplitudes of cone ERGs to increase with increasing adapting-field luminance. These response characteristics are similar to human ERGs using 30-Hz flicker stimuli, which suggests that flicker stimuli are a useful technique to isolate the cone function in rats.

Adaptation, Ocular↗
PubMed1998

Tetraploid embryos rescue embryonic lethality caused by an additional maternally inherited X chromosome in the mouse.

Mouse embryos with an additional maternally inherited X chromosome, i.e., disomic for XM (DsXM), cease to grow early in development and have a deficient extraembryonic region. We hypothesized that the underdeveloped extraembryonic region is attributed to two copies of XM that escape inactivation due to maternal imprinting. To examine the validity of this hypothesis and throw more light on the significance of X chromosome dosage on cell differentiation, we generated DsXM(XMXMXP and XMXMY) embryos at a high frequency taking advantage of the elevated incidence of X chromosome nondisjunction in female mice heterozygous for two Robertsonian X-autosome translocations, Rb(X.2)2Ad and Rb(X.9)6H. Although two XM chromosomes seem to remain active in both trophectoderm and primitive endoderm, detailed histological examination showed that the polar trophectoderm derivatives (ectoplacental cone and extraembryonic ectoderm) are severely affected, but the primitive endoderm derivatives (visceral and parietal endoderm) are relatively unaffected. Successful rescue of DsXM embryos by aggregation with tetraploid embryos show that X chromosome inactivation occurred normally leaving one X active in epiblast derivatives. Thus, two copies of active XM chromosome in cells of the polar trophectoderm cell lineage seem to be the main cause of early lethality shown by DsXM embryos as a result of failure in formation of ectoplacental cone and extraembryonic ectoderm.

Aneuploidy↗
PubMed1998

Cardioprotective effect of intravenous nicorandil in patients with successful reperfusion for acute myocardial infarction.

This study was designed to assess the cardioprotective effect of intravenous nicorandil, a potassium channel opener, in preventing reperfusion injury in acute myocardial infarction. Seventy patients were treated with placebo or nicorandil concomitant with reperfusion therapy in a prospective, randomized, double-blind fashion within 6 h after the onset of acute myocardial infarction. Nicorandil was administered before reperfusion as a 2-mg bolus iv injection followed by continuous infusion of 2-6 mg/h for the next 3 h. Thirty-six patients (17 in the placebo group, 19 in the nicorandil group) who demonstrated both complete occlusion of an infarct-related vessel before treatment and successful reperfusion were included in the final analysis. No significant changes in left ventricular ejection fraction were observed between the immediate and chronic phases in each group. In the analysis of regional ventricular function, the placebo group did not show any significant change in regional chord shortening (26.8+/-8.2 vs 24.3+/-7.3%, NS) or hypocontractile perimeter (36.4+/-28.2% vs 28.3+/-24.8%, NS) between immediate and chronic phase left ventriculograms. In contrast, in the nicorandil group, a significant increase in regional chord shortening (21.5+/-11.0% vs 25.8+/-11.3%, p<0.05) and a significant decrease in hypocontractile perimeter (33.3+/-19.6% vs 25.6+/-24.3%, p<0.05) were observed in the chronic phase left ventriculogram. Thus, nicorandil may be a useful adjunctive therapy for preserving myocardial contractile function in patients with acute myocardial infarction undergoing reperfusion therapy.

Acute Disease↗
PubMed1998

Efficacy and limitation of F-18-fluorodeoxyglucose positron emission tomography during fasting to assess myocardial viability in the acute phase of myocardial infarction.

OBJECTIVE: The present study was designed to determine the ability of positron emission tomography (PET) to assess myocardial viability and ischemia in acute myocardial infarction (MI) after reperfusion therapy (thrombolysis and/or coronary angioplasty). METHODS: PET with fluorine-18-labeled fluorodeoxyglucose (FDG) under fasting conditions and thallium-201 single-photon emission computed tomography (TL) were analyzed in 21 patients one week following MI. Myocardial viability was also assessed by regional wall motion using serial analysis of 2-D echocardiography or left ventriculography. RESULTS: Marked uptake of FDG together with a residual perfusion defect were observed in the infarct region in all patients one week post MI. However, in 9 of the 21 patients, the infarct-related coronary artery had no significant stenosis after reperfusion therapy and remained patent in one month post MI suggesting no myocardial ischemia. In contrast, in 4 of the 21 patients the regional wall motion was akinetic and there was a complete defect observed with TL imaging at one month post MI, indicating no viability in the infarct region. CONCLUSIONS: PET using fasting FDG at one week post MI had a limitation to predict myocardial viability or ischemia.

Acute Disease↗
PubMed1998

Carboxyflavins, novel inhibitors of Taq DNA polymerase.

Carboxyflavins were found to be potent selective inhibitors of Taq DNA polymerase in a polymerase chain reaction. The inhibitions were dose-dependent, and complete inhibitions were observed at the concentration of 3.0 microM. Carboxyflavins were much less, or not sensitive to the DNA polymerases tested such as calf thymus DNA polymerase alpha, rat DNA polymerase beta, human immunodeficiency virus type 1 reverse transcriptase, the Klenow Fragment of E. coli DNA polymerase I and T4 DNA polymerase. To our knowledge, there is no other report of an agent that selectively inhibits only a thermophilic polymerase. Interestingly, the carboxyflavins were able to prevent DNA synthesis in the murine lymphoid leukemia cell line L1210 in vitro; almost complete inhibitory levels were achieved in the range of less than 10 microM.

Animals↗
PubMed1998

Cisplatin neurotoxicity presenting as reversible posterior leukoencephalopathy syndrome.

Visual disturbance, hypertension, convulsions, and unconsciousness developed in a 70-year-old man after cisplatin chemotherapy and upper-limb amputation for osteosarcoma. MR imaging revealed bilateral reversible abnormalities in the occipital, parietal, and frontal white matter. Clinical and neuroradiologic features corresponded to reversible posterior leukoencephalopathy syndrome (RPLS), which some immunosuppressive and chemotherapeutic drugs have been reported to trigger. Cisplatin may be among these drugs. Our patient also had hypomagnesemia, which may have figured in the pathophysiology.

Aged↗
PubMed1998

[Molecular diagnosis of mitochondrial disorders].

Mitochondrial disorders are caused by either nuclear or mitochondrial DNA abnormalities. The latter but not the former can be examined as a means of diagnosis at present. The peculiarities and problems of the mtDNA test depend strongly on the characteristics of mtDNA itself, such as the multiplicity in number, vulnerability to mutation, and maternal transmission. The mtDNA abnormalities observed in patients with mitochondrial disorders indicate heteroplasmy, tissue/cell specificity, and threshold effects. It should be stressed that the presence of mutant mtDNA in an individual does not mean that he or she is ill. The problems of the mtDNA test could be solved if the genotype-phenotype relationship is farther elucidated in the future study.

DNA, Mitochondrial↗
PubMed1998

[Placing two parallel catheters by Seldinger's approach through the femoral artery for CT angiography and CT during arterioportography: evaluation of efficacy and safety].

The purpose of this study was to evaluate the efficacy and safety of placing two parallel catheters by Seldinger's approach through the femoral artery for CT angiography (CTA) and CT during arterioportography (CTAP). We performed an analysis of 30 patients. Two introducers were successfully placed in all cases. Only one minor complication was observed, a localized inguinal hematoma. The CTA/CTAP procedures were successful in all patients except six who had anatomical variations of the hepatic arterial supply. Our methods proved to be useful and safe for patients with standard hepatic arterial supply.

Angiography↗