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Biomedical subjects

K Numata

Publications and source records attributed to K Numata.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Clinical evaluation of controlled hypotensive anesthesia with MR7S1].

Efficacy, safety and the optimal dose of MR7S1, an injectable preparation of sodium nitroprusside, were studied in 37 patients (ASA class I and II) under nitrous oxide-oxygen-enflurane anesthesia. MR7S1 was administered by intravenous infusion. The dose of MR7S1 was increased gradually starting from 0.25 micrograms.kg-1.min-1 to the dose which could achieve the target value of systolic blood pressure (80-100 mmHg). Thereafter this dose level was maintained. During the period in which the dose was increased, the blood pressure was reduced in proportion to the rate of administration. With the rate of administration of 1.0 to 3.0 micrograms.kg-1.min-1, a significant decrease in systolic blood pressure (SBP) was observed compared with the pretreatment level of SBP. During the maintenance period, the SBP was maintained around 80 to 100 mmHg at a rate of administration of 0.25 to 3.5 micrograms.kg-1.min-1. Two out of 37 patients showed a slight decrease in PaO2, but these values returned to normal without any treatment. These findings suggest that MR7S1 is a useful agent to control blood pressure for the hypotensive anesthesia.

Adult↗
PubMed1994

[The effects of hyperventilation upon the spinal pain modulating system (second report)].

The purpose of this study is to investigate the effect of hyperventilation on the spinal pain modulating system by using naloxone. Under enflurane anaesthesia, cats were prepared with midcollicular decerebration and lumbar laminectomy. The spinal cord was transected at T12-L1. WDR cells, responding primarily to noxious peripheral stimuli, were sampled with a microelectrode at the depth of 2,000 microns from the cord dorsum. Following the control period, ventilation was adjusted to produce hypocapnia of PCO2 20-25 mmHg. After activities of WDR cells were well suppressed, naloxone 0.1 mg.kg-1 was given intravenously. Changes of firings of WDR cells were investigated. Returning to normocapnia, recovery of firings was followed. Hypocapnia of PCO2 20-25 mmHg significantly suppressed the activities of WDR cells. Naloxone significantly antagonized the suppressive effects of hyperventilation upon the activity of WDR cell. Our results suggest that the hyperventilation has suppressive effects on single-unit activity of WDR cell and the mechanisms of those suppressive effects are related to pain modulating system by endogenous opiates.

Action Potentials↗
PubMed1993

Comparison of DNA synthesis in white and brown adipose tissue in rats with ventromedial hypothalamic lesions.

Ventromedial hypothalamic (VMH) lesions cause excessive fat accumulation in white adipose tissue (WAT), and brown adipose tissue (BAT); however, little information is available on whether or not cell proliferation occurs in WAT and BAT after VMH lesioning. In this study, we determined the DNA content and thymidine incorporation in unilateral parametrial WAT and interscapular BAT 0, 1, 3, and 7 days after VMH lesioning, and examined the mechanism of increased DNA content in WAT. In rats with VMH lesions, the weight of WAT and BAT had increased significantly at 7 days, and the DNA content and thymidine incorporation of WAT had increased significantly at 3 days and continued to increase for up to 7 days, while those of BAT did not increase for as long as 7 days after VMH lesioning. Restricted food intake according to the pair-feeding method partially inhibited the increased DNA content in WAT. The increased DNA content in WAT was mostly restored but not completely by the administration of anti-insulin antibody, and by administration of propranolol, a beta-adrenergic blocker. The results demonstrated that VMH lesions induced DNA synthesis in WAT early after VMH lesioning, but did not induce DNA synthesis in BAT, and suggested that either hyperinsulinemia or a beta-adrenergic receptor mechanism or both may be responsible for the increased DNA content in WAT.

Adipose Tissue↗
PubMed1993

Pulmonary capillary pressure measured with a pulmonary arterial double port catheter in surgical patients.

We developed a pulmonary artery (PA) double port catheter technique for reliable clinical measurements of pulmonary capillary pressure (Ppc). In seven elective surgical patients, the PA double port catheter with the second PA port 1 cm proximal to the balloon was inserted. The two PA ports, connected to identical pressure measuring systems, provided the pulmonary arterial pressures (Ppa) distal and proximal to the balloon. After general anesthesia was stabilized, the two Ppas were measured simultaneously during a PA occlusion maneuver during 10 s of apnea. The instant of occlusion was determined precisely as the time when the two Ppa traces sharply diverged. A single exponential equation was fitted to the segment of distal Ppa tracing starting 0.3 s after the instant of occlusion. Ppc was determined as the value of the exponential fit extrapolated to time 0. In six of seven patients, PA occlusion occurred consistently in the early systolic phase regardless of the timing of balloon inflation. Mean Ppa, Ppc, and pulmonary arterial wedge pressure were 16.6, 11.8, and 7.6 torr. The ratio of venous to total resistance ranged from 0.37 to 0.54 (mean:0.46). We conclude that this technique is clinically feasible and valuable in precise definition of the instant of PA occlusion. By defining PA occlusion consistently, this technique can provide reliable Ppc estimation in the clinical settings.

Catheterization, Swan-Ganz↗
PubMed1993

Flow characteristics of hepatic tumors at color Doppler sonography: correlation with arteriographic findings.

OBJECTIVE: We studied benign and malignant hepatic tumors with color Doppler sonography and arteriography in order to correlate color Doppler flow characteristics with tumor hemodynamics (vascularity, arteriovenous shunting, and portal vein involvement) shown by arteriography. We also evaluated the usefulness of color Doppler flow characteristics in discriminating between tumor types. SUBJECTS AND METHODS: We performed color Doppler sonography and hepatic arteriography in 58 patients with 72 hepatic lesions larger than 2.0 cm in diameter. Differences in pulsatile flow (peritumoral or intratumoral) and the highest systolic peak flow velocities reached were evaluated on color Doppler sonograms and compared with arteriographic findings. RESULTS: Color flow sonograms were obtained in 43 of 45 hepatocellular carcinomas, 15 of 16 cholangiocellular carcinomas or hepatic metastases, and six of 11 hemangiomas. Mixed peritumoral and intratumoral pulsatile flow was shown by arteriography in highly vascular tumors. The mean peak systolic flow velocity seen in hepatocellular carcinomas (0.52 m/sec) significantly exceeded the velocity seen in hemangiomas (0.16 m/sec), but not the velocity seen in other malignant hepatic tumors (0.51 m/sec). Six hepatocellular carcinomas, one cholangiocellular carcinoma, and two hepatic metastases with peak systolic flow velocities greater than 0.80 m/sec were each proved arteriographically to have arteriovenous shunting or portal vein involvement. CONCLUSION: Color Doppler sonography was useful for evaluating hepatic tumor hemodynamics as seen at arteriography, and peak systolic velocity may be useful in differentiating malignant hepatic tumors from hemangiomas.

Adult↗
PubMed1993

Diagnosis of portal vein thrombosis in patients with hepatocellular carcinoma: efficacy of color Doppler sonography compared with angiography.

OBJECTIVE: The aim of this study was to determine the efficacy of color Doppler sonography in the diagnosis of portal vein thrombosis in patients with primary hepatocellular carcinoma. The findings on angiography were used as the gold standard for diagnosis. SUBJECTS AND METHODS: We compared the findings on color Doppler sonograms and hepatic angiograms in 18 patients with hepatocellular carcinoma and portal vein thrombosis and in 22 patients with hepatocellular carcinoma without portal vein thrombosis. In most patients, tumor-related thrombus of the portal vein was confirmed by autopsy or surgery. The sonographic criteria for diagnosing portal vein thrombosis included nonvisualization of portal vein flow, pulsatile flow in the thrombus, arterioportal shunts, and cavernous transformation of the portal vein. RESULTS: Nonvisualization of portal vein flow was the predominant color Doppler finding in all patients with portal vein thrombosis. Other flow abnormalities overlapped the finding of nonvisualization of portal vein flow in 10 of 18 patients with portal vein thrombosis. The sensitivity of color Doppler sonography was 100% for nonvisualization of portal vein flow, 89% for detection of pulsatile flow in the thrombus, 60% for detection of arterioportal shunts, and 100% for detection of cavernous transformation. Among these findings, pulsatile flow in the thrombus was diagnostic for pathologically proved neoplastic thrombi in the main portal vein; sensitivity and specificity were 89% and 100%, respectively, and accuracy was 96%. No portal vein that appeared normal on color Doppler sonograms was thrombosed on arteriograms. CONCLUSION: We conclude that color Doppler sonography is a useful means of imaging the vascular extension of a tumor-based thrombus and an accurate means of screening for portal vein thrombosis.

Angiography↗
PubMed1993

[Hemodynamic changes in patients with myocardial infarction while walking up and down stairs].

Hemodynamic changes while walking up and down stairs were studied in 53 myocardial infarction (MI) patients in the chronic phase and 31 adults of normal health. Electrocardiograms were recorded by a holter monitor and analyzed for arrhythmias and ST segment changes. Heart rate, systolic and dyastolic pressure, and pressure-rate product (PRP) were also measured by auto sphygmomanometer. These were measured at one minute intervals during the following period: resting in bed for 3 minutes in a supine position; walking to a stairway (1 minute); walking up and down 2 flights of stairs taking 30 seconds for each flight (total of 2 minutes) and returning to their bed (1 minute). All subjects then rested until they reached their starting PRP level. After walking up and down the stairs, the PRP increased significantly over that measured while the subjects were in a supine position for both the MI patients and those of normal health. However, the rate of increase for the MI patients was lower than that of the normal adults. Also, for MI patients older than 60, increases of the PRP were lower than the increases of the younger patients. This phenomenon may be due to low cardiac function, low cardiac reserve, vascular sclerosis, and the hemodynamical instability of the weak vasomoter reflex. In addition, the average recovery time after walking up and down the stairs was 1.9 minutes for MI patients, compared to 1.2 minutes for normal adults. 17% of the patients spent more than 3 minutes recovering, while the recovery times for all normal adults were within 2 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Studies on the mode of antifungal action of pradimicin antibiotics. I. Lectin-mimic binding of BMY-28864 to yeast mannan in the presence of calcium.

BMY-28864 (BMS-181184), a water-soluble pradimicin derivative, specifically bound on the yeast cell surface in the presence of calcium, which was considered to be the initial step that triggered chain reactions leading to the fungicidal action. Close cause-effect relationships of the cell wall binding of BMY-28864 with its antifungal activity and potassium leakage induction were observed by Candida albicans and Saccharomyces cerevisiae in the presence and absence of calcium. Using mannan and methyl alpha-D-mannopyranoside as specific sugars, the mode of binding of BMY-28864 to sugar was examined in vitro in the presence of calcium. Quantitative component analysis revealed that the precipitate of BMY-28864 with methyl alpha-D-mannopyranoside and calcium was a ternary complex possessing a molar component ratio of 2.1:4.3:1.0. These findings altogether proved that BMY-28864, although not protein, recognized specific sugars such as mannose in the same manner as lectin, and that the ternary complex formation of BMY-28864 with specific sugar and calcium was the first step for expression of the selective antifungal action of the pradimicin.

Adsorption↗
PubMed1993

Studies on the mode of antifungal action of pradimicin antibiotics. II. D-mannopyranoside-binding site and calcium-binding site.

Based on the structure-activity relationship data of BMY-28864 and related pradimicin derivatives, the calcium salt-forming ability and the D-mannopyranoside-specific visible absorption maximum shift of BMY-28864 were analysed in the ternary complex formation of BMY-28864 with D-mannopyranoside and calcium. The free C-18 carboxyl group of BMY-28864 was proved to be the sole site for binding to calcium, while no hydroxyl groups of the aglycone were involved in calcium salt formation. The stereospecific D-mannopyranoside-recognizing ability of BMY-28864 was completely abolished by removal of the C-5 disaccharide moiety, and, more particularly, of the C-5 thomosamine moiety. Close relationship of these findings with the antifungal action was also supported by the in vitro antifungal assay and the potassium leakage induction test.

Anthracyclines↗
PubMed1993

Increased hepatic arterial blood flow in acute viral hepatitis: assessment by color Doppler sonography.

To evaluate the effect of acute viral hepatitis on hepatic arterial blood flow, we performed color Doppler sonography with point-spectral analysis in 15 patients with acute viral hepatitis and compared the results with those in 15 normal volunteers. During the acute phase of hepatitis, the peak-systolic and end-diastolic velocity of the hepatic artery were significantly larger than those in normal arteries (p < 0.01). During the recovery phase, these indexes of the hepatic artery decreased significantly to the control levels (p < 0.01). The resistive indexes related to vascular resistance in the hepatic artery during the acute phase were significantly less than those in normal arteries (p < 0.01), and they increased significantly to the control levels during the recovery phase (p < 0.01). No significant correlation was found between these indexes of the hepatic artery and conventional liver function parameters. However, the interval between the acute phase and the recovery phase did correlate negatively with the peak-systolic velocity of the hepatic artery in the acute phase (r = -0.630, p < 0.05) and with the end-diastolic velocity (r = -0.514, p < 0.05). We conclude that color Doppler sonography is useful for imaging increased hepatic arterial blood flow in patients with acute viral hepatitis. We believe that increased hepatic arterial blood flow during the acute phase may provide a marker for earlier recovery from hepatitis-induced damage.

Acute Disease↗
PubMed1993

Morphological changes of Candida albicans induced by BMY-28864, a highly water-soluble pradimicin derivative.

The time course of BMY-28864-dependent morphological changes in Candida albicans A9540 was studied by electron microscopy. Scanning electron microscopy revealed that BMY-28864 often induced cell surface deformations such as abnormal swelling and bulging around budding sites and bud scars. The cell membrane damage was visualized by freeze-fracturing technique as deep pit-like invaginations. Transmission electron microscopy with thin-sectioned specimens also demonstrated that BMY-28864 induced cell membrane invaginations together with cell membrane detachment from the cell wall, nuclear membrane fragmentation and mitochondrial aberration. Statistical sequence analysis of the prominent BMY-28864-dependent morphological changes of the yeast cells led to the conclusion that BMY-28864 first attacked the cell membrane and then caused disintegration of other intracytoplasmic organelles, resulting in the lethal effect.

Anthracyclines↗
PubMed1993

Very low calorie diet-induced weight loss reverses exaggerated insulin secretion in response to glucose, arginine and glucagon in obesity.

To examine the cause of hyperinsulinemia in obesity, we determined plasma glucose, insulin, and C peptide responses to glucose (75g), arginine (0.5 g/kg body weight), and glucagon (1mg) in seven normal subjects and 20 obese subjects before and after weight loss by very low calorie diet therapy (Optifast, 240 kcal/day for 8 to 12 weeks). Integrated insulin and C peptide secretion in response to three different stimuli were markedly increased before weight loss and were significantly decreased following weight loss in response to glucose (mean +/- s.e. 36.6 +/- 6.4 vs. 18.4 +/- 2.6; 148.2 +/- 12.0 vs. 113.1 +/- 8.7 pmol/ml/h; P < 0.01), arginine (13.8 +/- 2.2 vs. 8.2 +/- 2.1; 94.8 +/- 11.2 vs. 66.0 +/- 6.1 pmol/ml/h; P < 0.01), and glucagon (16.5 +/- 2.7 vs. 10.7 +/- 1.5; 89.0 +/- 6.0 vs. 68.7 +/- 4.8 pmol/m/h; P < 0.01). The molar ratio of integrated C peptide to integrated insulin in response to all three stimuli was markedly decreased before, and this ratio significantly increased following weight loss (mean +/- s.e., 5.01 +/- 0.41 vs. 7.45 +/- 0.65; P < 0.01), and to arginine (7.78 +/- 0.61 vs. 10.97 +/- 1.28; P < 0.05), but not to glucagon (6.72 +/- 0.60 vs. 7.47 +/- 0.66). These findings suggest that both increased insulin secretion and decreased insulin clearance contribute to hyperinsulinemia in obese subjects. Improvement in these abnormalities to all three stimuli after weight loss also suggests that hyperinsulinemia in obesity is a consequence of the obesity itself rather than a pre-existing disorder.

Adolescent↗
PubMed1992

Electrophysiologic findings in optic nerve dysfunction associated with multiple evanescent white-dot syndrome.

Electrophysiologic findings in a case of multiple evanescent white-dot syndrome were studied. A 37-year-old woman presented with multiple white dots, granularity of the macula, and optic disc swelling in her left fundus. The electroretinogram and electro-oculogram revealed abnormal findings indicative of changes in the retinal pigment epithelium and photoreceptors. In addition, relative afferent pupillary defect, enlargement of the blind spot, a decrease in the critical fusion frequency, staining of the optic disc on fluorescein angiography and prolonged latency of the P100 component with decreased amplitude in pattern-reversal visual evoked cortical potential strongly suggested dysfunction of the optic nerve in this patient.

Adult↗
PubMed1992

Serial measurement of urinary VMA and HVA levels from one infant: a study for neuroblastoma mass screening.

Urinary vanillylmandelic acid (VMA), homovanillic acid (HVA), and creatinine in 188 samples from one infant during the ages of 1 to 12 months were measured serially by high-performance liquid chromatography (HPLC). The mean VMA and HVA levels of the total 188 samples in this study were 11.9 +/- 1.39 and 22.9 +/- 2.92 micrograms/mg creatinine with coefficients of variation (CVs) 11.7% and 12.8%, respectively; and of 76 samples from 5 to 12 months of age, 12.3 +/- 0.84 and 23.1 +/- 2.03 micrograms/mg creatinine with CVs 6.8% and 8.8%. The CVs of VMA and HVA levels expressed in microgram per milligram of creatinine had decreased after 6 months of age (VMA, 5.0% to 8.3%, HVA, 5.3% to 8.4%). Chromatograms demonstrated the similar pattern from 1 to 12 months of age, although the infant had been fed foods typical in Japan, which included breast milk, seasonal fruits, vegetables, fish, chicken, and meat. Diurnal fluctuations of VMA and HVA levels in urine were not significant. When HPLC is used for measurement of VMA, HVA, and creatinine, it is not necessary to restrict foods that cause false-positive results in the qualitative VMA test from the infant's diet. Furthermore, random urine samples obtained throughout the 12 months could be effectively used for the measurement of these substances.

Chromatography, High Pressure Liquid↗
PubMed1992

Crystallization and preliminary X-ray studies of a Bacillus subtilis and Thermus thermophilus HB8 chimeric 3-isopropylmalate dehydrogenase and thermostable mutants of it.

A new type of chimeric 3-isopropylmalate dehydrogenase (2T2M6T) was produced by expressing the fused gene of Bacillus subtilis and Thermus thermophilus. The enzyme shows heat stability intermediate between those of the parents. The crystal of the enzyme belongs to the space group of P3(2)21, with cell dimensions of a = b = 78.9 A and c = 158.9 A. Two thermostable mutants of the chimeric enzyme were prepared by site-directed mutagenesis and then crystallized.

3-Isopropylmalate Dehydrogenase↗
PubMed1992

Hepatocellular carcinoma: treatment with percutaneous ethanol injection and transcatheter arterial embolization.

The therapeutic effectiveness of a new combination therapy--pretreatment with transcatheter arterial embolization (TAE) and subsequent percutaneous ethanol injection (PEI)--for solitary large (> 3.0 cm in diameter) primary hepatocellular carcinoma lesions was compared with that of TAE alone. With TAE alone, a partial response of the tumor was seen in only 10% of the patients, and the 1-, 2-, and 3-year survival rates were calculated to be 68%, 37%, and 0%, respectively. Histologic examination of specimens obtained at hepatectomy showed that TAE alone caused complete necrosis in only 20% of the tumors. In contrast, PEI combined with TAE significantly (P < .05) increased the partial response rate (45%) and significantly (P < .01) prolonged the 1-, 2-, and 3-year survival rates (100%, 85%, and 85%, respectively). Combination therapy caused complete histologic necrosis in 83% of the tumors. It also was significantly (P < .05) better than TAE alone in terms of rate of primary tumor recurrence during follow-up.

Aged↗