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Biomedical subjects

T Minami

Publications and source records attributed to T Minami.

At least 253 records · Page 14Linked to original sources
PubMed1993

Influence of ramp slope on intracellular pH threshold during progressive exercise.

The purpose of this study was to examine the effect of ramp slope during progressive exercise test on the intracellular pH threshold (pHT) of working muscle. To attain the purpose, we measured intracellular pH of wrist flexor by 31P-MRS during four kinds of ramp wrist flexion. Five Japanese males participated as subjects. They performed wrist flexion in a bore of MRS system, with ramp increments of 0.14, 0.20, 0.26 and 0.31 W/min till exhaustion. Intracellular pH of wrist flexor muscle was estimated from a chemical shift between inorganic phosphate (Pi) and phosphocreatine (PCr) on a 31P-MR spectra. Pi-to-PCr ratio (Pi/PCr) as an index of oxidative phosphorylation potential was also calculated. pH and Pi/PCr were obtained as minute-by-minute data throughout the exercise. pHT was determined as a work rate (W) just before that at which the intracellular acidosis (acidemia) occurred. Although work endurance was shortened significantly, achieved maximal work rate (WRmax) was increased with an increase in ramp slope. pHT both in the unit of W and %WRmax was not affected significantly by the ramp slope. On the other hand, Pi/PCr at pHT decreased with an increase in ramp slope, significantly. These results suggested that intracellular homeostasis with reference to acid-base equilibrium was not dependent on oxidative phosphorylation status, but a work output of the muscle.

Exercise↗
PubMed1993

Effect of restricted blood flow on intracellular pH threshold of working muscle.

Threshold of decline in intracellular pH of muscle (pHT) during incremental wrist flexion was studied by 31P-MRS, under two levels of occlusions in which the cuff of the upper arm was inflated to systolic (ES) and diastolic blood pressure (ED), and no occlusion (E). To observe the effect of occlusion per se, intracellular pH at rest under the same two levels of occlusion was measured. Additionally, NIRS was applied to monitor the oxygenation and blood volume of the tissue during the same experimental protocol as the 31P-MRS study. Ten healthy Japanese males participated as subjects in the 31P-MRS study, and three of them in the NIRS study. They performed wrist flexion in incremental loads of 0.14 W/min ramp until voluntary exhaustion. 31P-MRS and NIRS were obtained from wrist flexor muscles. Change in intracellular pH (pH) during wrist flexion showed a threshold behavior even in ischemic conditions, although pH did not decrease at rest under the same two levels of occlusion. This finding indicated that decrease in pH under occlusion is also resulted from exercise induced lactic acidosis. Obtained pHT in ES was smaller than in ED and E significantly, and there was no significant difference between pHT in ED and that in E. From the results of NIRS study, it was confirmed that only venous outflow but not arterial inflow was restricted under an occlusion at a pressure of diastolic blood pressure, but both under an occlusion at a pressure of systolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1993

Regional blood flow volume in the eustachian tube.

Measurements of regional blood flow around the pharyngeal orifice of the Eustachian tube were carried out after topical administration of various inflammatory mediators in 14 mongrel dogs by the hydrogen clearance method. Histamine and platelet-activating factor (PAF) resulted in a significant alteration of blood flow volume. Histamine was found to induce a dose-response related increase, whereas blood flow volume tended to decrease in each concentration range in the series of PAF administration. There was no significant difference in blood flow between topical application of leukotriene C4 and leukotriene D4. It is likely that in upper respiratory tract inflammation, such as in otitis media and in nasal allergy, activated histamine and PAF affect the microcirculation of the tubal orifice. These results suggest that disturbance of the microcirculatory system in the Eustachian tube mucosa could be involved in the pathogenesis of chronic otitis media with effusion.

Animals↗
PubMed1993

Head and neck reconstruction with microvascular tissue transfer and its surgical indications: our experiences. A review.

Microvascular tissue transfer has facilitated the primary closure of various complex defects after radical ablation of head and neck cancers. Recently, we have begun to use the forearm flap, osteocutaneous scapular flap, rectus abdominis myocutaneous flap, latissimus dorsi myocutaneous flap and jejunal autografts for reconstruction of the head and neck region following cancer ablation and have recognized further evidence of the versatility of free grafts. In this paper, we describe the results of 69 cases between 1987 and 1991 and the operative indication for microvascular tissue transfer in the head and neck region.

Adult↗
PubMed1993

[A case of sudden death of a patient with glycogen storage disease type 1--delayed aftereffect of a traffic accident].

A case of sudden death of a 22-year-old man with glycogen storage disease type 1 is reported. Autopsy revealed striking hepatomegaly with round edges. The liver was yellowish and weighed 2840 g. Histologic findings showed excessive deposition of PAS-positive material in the hepatocytes and in the proximal renal tubular epithelium cells, which means the accumulation of glycogen. A mass surrounding splenic artery was seen in the hilus of the spleen. There was about 2000 ml of fresh blood and clots in the abdominal cavity due to bleeding from a ruptured mass. The mass was composed of a hematoma with connective tissue surrounding it and was a pseudoaneurysm. The mass was considered to have been formed from bleeding due to injury to a branch of a splenic artery. Consideration of these findings led to the conclusion that death was caused by loss of blood from rupture of the mass and that the mass was formed due to injury of the branch of the splenic artery in a traffic accident 2 years earlier but not the pathogenesis of glycogen storage disease.

Accidents, Traffic↗
PubMed1993

[Effect of Ca-antagonists on pulmonary blood flow during single-lung ventilation in the dog].

Experiments were conducted in 21 adult mongrel dogs to clarify the effects of Ca-antagonist (nifedipine sublingual administration 2.5 mg or 5 mg, or nicardipine intravenous administration 30 micrograms/kg or 60 micrograms/kg) on pulmonary blood flow under the condition of collapsed lung on the side of thoracotomy. Under anesthesia, an endotracheal tube with a movable blocker was used to intubate the trachea and the thoracotomized lung was collapsed. Subsequently, a Ca-antagonist was given and the ratio of the left main pulmonary artery/ascending thoracic aorta blood flow was used as an index of hypoxic pulmonary vasoconstriction (HPV). The following results were obtained. 1. Ca-antagonist administration under lung-collapse on the thoracotomy side resulted in inhibition of HPV of the collapsed lung, whereas, arterial blood oxygen tension (PaO2) remained in the acceptable range. 2. The maintenance of the lowered PaO2 within the acceptable range may have been due to the increase in cardiac output and the elevation of mixed venous blood oxygen tension resulting from Ca-antagonist administration, as well as the residual HPV even after administration of the Ca-antagonist.

Animals↗
PubMed1993

[An experimental study on the relation between lung volume and pulmonary blood flow].

The purpose of this study was to elucidate whether or not the reduction of lung volume is related to the mechanism of blood flow reduction in the atelectatic lung. In adult mongrel dogs, whose main stem bronchus in the thoracotomized lung was obstructed, the change of blood flow in the lung containing N2 was compared with that in the collapsed lung. 1) Under a low partial pressure of O2 in the broncho-alveolar system by obstruction of the main stem bronchus, the blood flow did not change, even when the N2 volume in the lung was varied. Therefore, the change of blood flow in the collapsed lung is not attributable to the reduction of lung volume. 2) The lung blood flow increased when the partial pressure of O2 in the broncho-alveolar system was elevated by infusion of O2 into the collapsed lung, and it decreased with the subsequent O2 absorption leading to lung collapse. Therefore, the change of lung blood flow is due to the change of intraalveolar partial pressure of O2. 3) The reduction of blood flow in the atelectatic lung is caused by hypoxic pulmonary vasoconstriction, and is not influenced by the reduction of lung volume due to the lung collapse.

Animals↗
PubMed1993

Elevation of phospholipase A2 protein in sera of patients with Crohn's disease and ulcerative colitis.

The protein mass of group II phospholipase A2 (PLA2) levels were immunochemically measured in sera of 43 patients with Crohn's disease (CD), 43 patients with ulcerative colitis (UC), and 35 healthy volunteers, and compared with PLA2 enzymatic activity. Serum immunoreactive group II PLA2 (IR-PLA2 II) levels of active CD patients were significantly higher than those of the controls and inactive CD patients. Serum IR-PLA2 II levels were also significantly greater in patients with severe UC and moderate UC than in the controls and patients with mild UC. Serum IR-PLA2 II levels were found to be closely correlated with serum PLA2 activity in patients with CD and UC. Serum IR-PLA2 II levels and PLA2 activity decreased by antiinflammatory treatment in six patients with CD and two with UC. These results suggest that serum IR-PLA2 II levels can be a useful parameter in the evaluation of disease activity of CD and UC, and that elevated PLA2 enzymatic activity in sera of patients with CD and UC is attributable to increased protein concentration of group II PLA2, in agreement with our previous results.

Adolescent↗
PubMed1993

[Hepatic arterial infusion chemotherapy combined with calcium antagonist for liver metastases].

We noticed inactivation of calcium antagonists in liver and investigated treatment with combined intraarterial chemotherapy. Both verapamil (VER) and adriamycin were infused into the hepatic artery of patients with liver metastases. The serum concentration of VER in the hepatic vein was 0.325 +/- 0.203 g/ml at maximum in 11 cases receiving bolus infusion. Blood pressures, heart rates and electrocardiograms were stable. The concentration in the peripheral vein was lower (0.089 +/- 0.027 g/ml) in 4 cases receiving 3-hour continuous infusion. Five patients received more than 10 infusions, and a partial response was observed in 2 cases. A more appropriate dose and the corresponding prognosis should be studied in the future.

Adult↗
PubMed1992

Malignant anterior uveal melanoma with diffuse metastasis in a dog.

Enucleation was performed in 10-year-old sexually intact female mixed-breed German Shepherd Dog. Histologic examination revealed that the dog had an uveal amelanotic melanoma of the eye. The tumor consisted of anaplastic cells with a high mitotic index, indicating malignancy. On examination 3 months after enucleation, the dog had difficulty breathing and nasal discharge. Radiography revealed pulmonary metastasis. The dog was euthanatized. Necropsy revealed diffuse metastasis involving various organs.

Animals↗
PubMed1992

Chloride-37 nuclear magnetic resonance spectroscopic study of binding of salicylic acid and other hydroxybenzoic acids to the band 3 anion transport protein of human erythrocytes.

Chloride-37 nuclear magnetic resonance spectroscopy was used to investigate the displacement of chloride (Cl-) from binding sites on band 3 anion transport protein in human erythrocytes by salicylic acid and five other hydroxybenzoic acids (HAs). All the HAs studied displaced Cl- from these binding sites. The association constants for binding of the HAs to band 3 anion transport protein were larger than that for Cl- and dependent on the specific structural features of the molecule, rather than general physicochemical characteristics.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1992

A kinetic study of the role of band 3 anion transport protein in the transport of salicylic acid and other hydroxybenzoic acids across the human erythrocyte membrane.

The mechanism of transport of salicylic acid and five other hydroxybenzoic acids across the human erythrocyte membrane was investigated. The specific anion transport inhibitor, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, reduced but did not totally abolish transport of these acids. This observation suggests that these acids are transported by two parallel processes, one involving the band 3 anion transport protein channel and the other probably involving passive diffusion of the un-ionized molecule. The activation energies for membrane transport were large (99-127 kJ.mol-1), an observation that is consistent with the rate-limiting step for anion transport being the conformational change of the band 3 anion transport protein.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1992

Babesia ovata: isolation from erythrocytes and development of an enzyme-linked immunosorbent assay for detection of antibodies.

A method of isolating Babesia ovata merozoites from infected erythrocytes and an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-B. ovata antibodies were developed. After B. ovata-infected erythrocytes had been lysed using the nitrogen cavitation method, the merozoites were separated from erythrocyte components by differential centrifugation and density-gradient centrifugation. The light microscopic examination showed that the purified merozoites were morphologically intact and contained few contaminants. Sodium dodecyl sulfate-polyacrylamide electrophoretic (SDS-PAGE) analysis revealed that the merozoite fraction contained very little contamination with erythrocyte components. The merozoites thus obtained were sonicated and treated with Triton X-100 and then used as an antigen to measure anti-B. ovata antibodies in ELISA. The ELISA was more sensitive in detecting anti-B. ovata antibodies than was either the indirect fluorescent antibody test or the complement fixation test on sera from cattle infected with B. ovata.

Animals↗
PubMed1992

Raised serum activity of phospholipase A2 immunochemically related to group II enzyme in inflammatory bowel disease: its correlation with disease activity of Crohn's disease and ulcerative colitis.

Calcium dependent phospholipase A2 activity in the mixed micelles of 1-palmitoyl-2-oleoyl-phosphatidylglycerol and cholate was measured in sera of 39 patients with Crohn's disease, 40 patients with ulcerative colitis, and 40 healthy controls. The phospholipase A2 activity was significantly raised in those sera of the patients with active Crohn's disease and those with moderate and severe ulcerative colitis. The major phospholipase A2 activity derived from the sera was separated into two peaks by reverse phase high performance liquid chromatography. The phospholipase A2 active fractions were immunochemically characterised using specific antibody directed against human group II phospholipase A2 purified from rheumatoid synovial fluid. The results suggest that raised serum phospholipase A2 activity in patients with Crohn's disease and ulcerative colitis was mainly attributed to the two forms of phospholipase A2 immunochemically related to group II enzyme. In patients with Crohn's disease, serum phospholipase A2 activity decreased in parallel with clinical improvement, and correlated with serum C-reactive protein and erythrocyte sedimentation rate. The results suggest that serum phospholipase A2 activity may serve as an additional indicator of disease activity. Serum phospholipase A2 activity in patients with ulcerative colitis tends to increase in relation with endoscopic severity, and may be a more sensitive laboratory index than serum C-reactive protein and erythrocyte sedimentation rate to evaluate disease activity.

Acute Disease↗
PubMed1992

Noncariogenicity of maltitol in specific pathogen-free rats infected with mutans streptococci.

The effect of maltitol on caries development was examined in an experimental caries system employing specific pathogen-free (SPF) Sprague-Dawley rats. Fourteen strains of oral streptococci, including mutans streptococci, did not utilize the maltitol nor produce sufficient acid to demineralize tooth enamel. Furthermore, maltitol did not serve as a substrate for glucosyltransferases of either Streptococcus mutans MT8148R or Streptococcus sobrinus 6715 to synthesize water-insoluble glucan. Maltitol induced no significant dental caries in SPF rats infected with these mutans streptococci, and replacement of the dietary sucrose content with maltitol resulted in a trend towards caries reduction in SPF rats.

Animals↗
PubMed1992

The effects of adenine and dimethyl sulfoxide on the mouse pancreas.

The authors have studied the effects of dimethyl sulfoxide (DMSO) on the plasma alpha-amylase activity in mice that sustained a pancreatic injury induced by an oral administration of adenine. In mice given a 5% solution of DMSO as drinking water for 3 d prior to the administration of adenine (175 mg/kg), and also drank this DMSO solution until the end of the experiment, hyperemia of the pancreas was observed and the level of plasma alpha-amylase activity became significantly higher than the level seen in the control mice. A pathological examination also revealed vacuolation and zymogenic degranulation. Further, the plasma alpha-amylase activity level increased only in mice given this 5% DMSO solution, and no increase was noted in mice given a 3% or a 1% DMSO solution for drinking water. Further, the pancreatic lipid peroxide level of mice given this 5% DMSO solution was significantly higher than the level seen in the control group. Based on the above results and associated data, it is thought that an oral administration of adenine can induce a pancreatic injury in the mouse, and that this injury is sustained with the assistance of DMSO.

Adenine↗
PubMed1992

[Changes in intracellular pH of working muscle during constant and stepwise incremental load exercise].

In this study, subjects performed wrist flexion in isokinetic manner by using CYBEX dynamometer while their right forearm was attached in a MR magnet. 31P-MR spectra were obtained from wrist flexor muscles before and throughout the exercise. Intracellular pH of muscle was calculated from the chemical shift between phosphocreatine (PCr) and inorganic phosphate (Pi). Fifteen Japanese males volunteered as subjects. They performed two experimental protocols, i. e. constant load test (CT) and stepwise incremental load test (IT). In CT, 10 of the subjects were participated. After 2 minutes rest, wrist flexion of 10, 20, 30, 40 or 50% of maximal voluntary contraction force (MVC) was performed at 2 seconds intervals for 15 minutes. In IT, 14 including 9 of CT were participated. They performed wrist flexion in incremental contraction force of 5 steps from 10% to 50% of MVC for 3 minutes in each step. Changes in intracellular pH of muscle against contraction level show non-linear relationships both in CT and IT. From this relationship we calculated the contraction level at which pH was 6.9 (%MVC6.9). Mean values of obtained %MVC6.9 by CT and by IT were 29.3 and 30.0% of MVC, respectively. And, significant correlation was found between %MVC6.9 by CT and by IT. This result shows that %MVC6.9 was a reproducible index independent of the type of exercise test, i. e. constant or incremental load test, and might reflect the physiological characteristics of the muscle.

Exercise↗