Search PubMed⌕ Search

Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 595 records · Page 33Linked to original sources
PubMed1989

Idiopathic esophageal varices with longitudinal erosion.

A 60-year-old man with idiopathic esophageal varices is presented. Endoscopy and endoscopic ultrasonography clearly demonstrated a longitudinal erosion on one of two straight varices. There was no evidence of portal hypertension, and no abnormality in the superior vena cava system. Peritoneoscopy and liver biopsy were normal. These varices with longitudinal erosion represent unique endoscopic findings as compared with previously reported cases. There has been no variceal bleeding during a 6-year follow-up.

Esophageal and Gastric Varices↗
PubMed1989

Effect of bicarbonate on the growth of Actinobacillus actinomycetemcomitans in anaerobic fructose-limited chemostat culture.

The effect of bicarbonate on the growth and product formation by a periodontopathic bacterium, Actinobacillus actinomycetemcomitans, was examined in an anaerobic chemostat culture with fructose as the limiting nutrient. The chemostat cultures were run at dilution rates between 0.04 and 0.25 h-1 and the maximum growth yield (Ymax fructose) was estimated to be 40.3 and 61.7 g dry wt (mol fructose)-1 in the absence and presence of bicarbonate, respectively. The major fermentation products in the absence of bicarbonate were formate, acetate, ethanol and succinate, with small amounts of lactate. The addition of bicarbonate to the medium resulted in a marked decrease in ethanol production and in a significant increase in succinate production. Washed cells possessed activity for the cleavage of formate to CO2 and H2, which seemed to play a role in supplying CO2 for the synthesis of succinate in the absence of bicarbonate. The study of enzyme activities in cell-free extracts suggested that fructose was fermented by the Embden-Meyerhof-Parnas pathway. The values of Ymax ATP and the efficiency of ATP generation (ATP-Eff) during fructose catabolism were estimated and higher values were obtained for the culture in the presence of bicarbonate: 20.2 g dry wt (mol ATP)-1 and 3.0 mol ATP (mol fructose)-1, respectively, versus Ymax ATP = 15.1 and ATP-Eff = 2.7 in the absence of bicarbonate.

Actinobacillus↗
PubMed1989

Characterization of a cell-surface protein antigen of hydrophilic Streptococcus mutans strain GS-5.

Fourteen strains of Streptococcus mutans serotype c were examined for their cell-surface protein antigens in terms of hydrophobicity, Mr and immunochemical specificities. Thirteen strains were hydrophobic, while strain GS-5 was markedly hydrophilic as compared to the other strains tested. Cell-surface protein antigens were then analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western immunoblotting. A protein antigen of Mr 190,000 (PAc) was found in cell extracts and culture supernatants of all the hydrophobic strains. Neither culture supernatant nor cell extract of strain GS-5 contained PAc. Strain GS-5, however, produced extracellularly a large amount of a protein of Mr 155,000 (PAGS-5) which reacted with rabbit anti-PAc serum. Immunodiffusion analysis showed that PAGS-5 lacked a part of the antigenic moieties in the PAc molecule. SDS-PAGE and radioimmunoassay showed a small amount of PAGS-5 on the cell surface of strain GS-5. These findings suggest that PAGS-5 may correspond to PAc which lacks a region participating in binding of PAc to the streptococcal cell.

Antigens, Bacterial↗
PubMed1989

Sensitivity of arterial baroreflex changes during daily activity.

1. Continuous ambulatory arterial pressure monitoring was performed by telemetry in 34 hypertensive and four normotensive subjects and arterial baroreflex sensitivity was evaluated by computer analysis of pulse wave. Three consecutive pulses were selected, on two criteria, from the 24 h recording: (i) progressive and linear increase or decrease in systolic arterial pressure and heart period, (ii) change of systolic arterial pressure in three pulses exceeds a threshold value. The systolic arterial pressure and heart period of three pulses were averaged and the slopes of systolic arterial pressure and heart period were calculated as baroreflex sensitivity. 2. When the threshold value was set to 5 mmHg, baroreflex sensitivity measured by the present method correlated with baroreflex sensitivity as measured by the phenylephrine method (r = 0.667, P less than 0.001). 3. The baroreflex sensitivity from the pressor-bradycardia and the depressor-tachycardia reflex decreased as threshold value was increased from 3 to 4 mmHg to over 20 mmHg. With the pressor-bradycardia reflex, the initial systolic arterial pressure of three pulses did not change, but the initial heart period shortened progressively as the threshold increased. With the depressor-tachycardia reflex, the initial systolic arterial pressure increased and the initial heart period shortened progressively. This suggests that the sensitivity of arterial baroreflex changes dynamically according to input of reflex are during daily activity.

Adult↗
PubMed1989

Cardiovascular effects of the N-methyl-D-aspartate receptor antagonist MK-801 in conscious rats.

Evidence from microinjection studies in anesthetized rats suggests that central excitatory amino acid pathways using N-methyl-D-aspartate receptors are involved in the regulation of the cardiovascular system. To test the hypothesis that these pathways are tonically involved in the maintenance of or the baroreceptor reflex regulation of cardiovascular function, we have examined the effects of intravenous injection of the centrally acting, noncompetitive N-methyl-D-aspartate receptor antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801), on the mean arterial pressure, heart rate, renal sympathetic nerve activity, and behavior of conscious, freely moving sham-operated and sinoaortic baroreceptor-denervated rats. Administration of MK-801 produced, within 5 minutes, dose-dependent elevations in mean arterial pressure, heart rate, and renal sympathetic nerve activity that were sustained for 0.5 to 2.5 hours. For an equivalent dose, MK-801 produced approximately twice the peak changes in mean arterial pressure and heart rate in the sinoaortic baroreceptor-denervated rats than in the sham-operated rats. Pretreatment results were as follows: 1) The ganglion blocker chlorisondamine markedly attenuated the hypertension and tachycardia in the sham-operated and sinoaortic baroreceptor-denervated rats, 2) pretreatment with the alpha 1-adrenergic receptor antagonist prazosin virtually abolished the hypertension, and 3) the beta 1-adrenergic receptor antagonist atenolol markedly reduced the tachycardia. MK-801 also produced stereotypic behaviors and ataxia in the sham-operated and sinoaortic baroreceptor-denervated rats; however, qualitatively and quantitatively similar changes in behavior were induced in the latter by doses approximately five time lower than required in sham operated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Developmental change in subjective probability during adolescence.

The developmental change in subjective probability during adolescence, an important period for establishing the probability concept, was investigated. 75 Japanese adolescents, from 12 to 23 yr. of age, were asked to make probability judgments for a lottery under 15 conditions. Analysis showed that with increase in age their subjective probability came closer to the objective probability. Discussion of these results took into consideration recent studies on the development of the concept of probability.

Adolescent↗
PubMed1989

Attempts at estimating mixed venous carbon dioxide tension by the single-breath method.

The single-breath method was originally proposed by Kim et al. [1] for estimating the blood carbon dioxide tension and cardiac output. Its reliability has not been proven. The present study was undertaken, using dogs, to compare the mixed venous carbon dioxide tension (PVCO2) calculated by the single-breath method with the PVCO2 measured in mixed venous blood, and to evaluate the influence of variations in the exhalation duration and the volume of expired air usually discarded from computations as the deadspace. Among the exhalation durations of 15, 30 and 45 s tested, the 15 s duration was found to be too short to obtain an analyzable O2-CO2 curve, but at either 30 or 45 s, the calculated values of PVCO2 were comparable to the measured PVCO2. A significant agreement between calculated and measured PVCO2 was obtained when the expired gas with PCO2 less than 22 Torr was considered as deadspace gas.

Animals↗
PubMed1989

Technetium-99m (V) DMSA uptake in amyloidosis.

Technetium-99m(V) DMSA scintigraphy was performed in two patients with pathologically confirmed amyloidosis associated with plasmacytoma. Significant uptake of the tracer was found in the deposition of amyloid. Technetium-99m(V) DMSA scintigraphy could be useful in determining the appropriate region of biopsy and in forecasting the prognosis of patient with plasmacytoma.

Aged↗
PubMed1989

[Clinical evaluation of serum sialyl SSEA-1 (SLX) in diagnosis of cancers].

In order to evaluate the usefulness of sialyl SSEA-1 (SLX) as a tumor marker of digestive cancers, serum levels of the antigen were determined in 334 patients with malignancies and 196 patients with benign diseases. The results indicated that positivity of the antigen in sera from malignant patients was highest in pancreatic cancer (58%) and biliary tract cancer (56%). False positive incidence of SLX in sera from benign diseases was as low as 6%, revealing low false positivity. Comparison with other tumor markers such as CA19-9, CA-50, CEA and ST-439 showed that positivity of SLX was as high as that of CEA, whereas it was lower than that of CA19-9 or CA-50. On the other hand, false positivity of SLX as well as ST-439 was lowest, and accuracy of SLX was no less high than that of CA19-9 or CA-50. In sera of pancreatic and biliary tract cancer, positive incidences of CA19-9, CEA and ST-439 were 80%, 64% and 53%, respectively, and the diagnostic efficiency increased by combined assay of SLX with CA19-9 (88%), CEA (81%) and ST-439 (71%). SLX appears to be no less useful than the other recently developed carbohydrate antigens or CEA as serum tumor marker for pancreatico-biliary cancer.

Biliary Tract Neoplasms↗
PubMed1989

Partial agonist activity of celiprolol as assessed in conscious unrestrained dogs in comparison with those of pindolol and labetalol.

The effects of celiprolol on the heart rate (HR) and the total peripheral resistance (TPR) were studied in chronically instrumented conscious dogs in comparison with those of pindolol, propranolol and labetalol. Intravenous injection of pindolol, celiprolol and labetalol increased the HR and decreased the TPR dose-dependently, whereas propranolol did not. The ratios of doses that elicited 12% changes in both parameters (HR12/TPR12) were 4.85 +/- 2.63, 0.61 +/- 0.03 and 0.42 +/- 0.11 for celiprolol, pindolol and labetalol, respectively, indicating the preferential reduction of TPR by celiprolol. Changes in HR and TPR produced by these three agents were antagonized by propranolol dose-dependently. However, inhibition by 3 mg/kg of propranolol was incomplete in the cases of labetalol-induced decrease in the TPR at the dose of TPR12 (51%) and celiprolol-induced increase in the HR at the dose of HR12 (89%). These results suggest that changes produced by celiprolol as well as pindolol and labetalol were mostly explainable by partial agonist activity via beta-adrenoceptors. However, the contribution of the alpha-blocking activity must also be taken into consideration in the case of the reduction of the TPR by labetalol. In addition, there is a possibility that celiprolol may increase HR via its direct action.

Adrenergic alpha-Agonists↗
PubMed1989

[Changes in bone mineral content and bone metabolism related to menopause].

Although the phenomenon of postmenopausal osteoporosis has attracted attention, there have been no parameter-matched studies of pre- and postmenopausal difference in metacarpal bone mineral status and bone metabolism. Therefore the authors compared metacarpal bone loss in a group of 41 postmenopausal volunteers (average postmenopausal duration: 39.3 months) and 28 age- and body size-matched controls (age 50-54), using the MD method. Perimenopausal changes in bone metabolism were also examined in these groups. The result revealed that the reduction in the metacarpal bone mineral status due to menopause occurs mainly in the bone mineral density such as GSmin and sigma GS/D. The reduction rate was the highest for the index of GSmin, corresponding to 5.1% per year. Serum levels of Alp and osteocalcin were significantly higher and the U-Ca/cr ratio tended to be higher in the postmenopausal subjects than in controls. The serum levels of calcium regulating hormones such as PTH and calcitonin in these two groups did not differ significantly. However the estrone and the estradiol levels, were significantly lower in postmenopausal subjects. Significant correlations were found between Alp and the postmenopausal period (r = 0.4684), and between the U-Hpr/cr ratio and postmenopausal period (r = -0.5332). It therefore appeared that estradiol is mainly related to postmenopausal bone metabolism causing insufficient suppression of bone resorption. However, calcium regulating hormones appeared to be not directly related to the postmenopausal bone loss mechanism. Bone turnover decreased with the postmenopausal period.

Alkaline Phosphatase↗
PubMed1989

[Assessment of osteopenia following oophorectomy by quantitative computed tomography and its relation with Ca-regulating hormones].

In order to determine the pathogenesis of post-oophorectomy osteopenia, we investigated the bone mineral status and biochemical parameters, and identified high-turnover bone metabolism. The present study was undertaken to determine whether there is a decrease in bone mineral content of peripheral bone or axial bone and cortical bone or trabecular bone using the microdensitometry method and a modified quantitative computed tomography method in 40 [24 premenopausal females (controls) and 16 premenopausal females who underwent oophorectomy]. We also investigated what biochemical and endocrinological parameters are changed, for example, Ca-regulating hormones and sex steroids, etc. As a result, it found that the reduction in bone mineral content due to oophorectomy occurs mainly in the axial bone, especially in the trabecular bone. It was considered that oophorectomy causes high-turnover osteopenia, in which bone formation is promoted but is outweighed by bone resorption, resulting in an overall decrease in bone mineral content. It also seemed that E2 is significantly related to bone metabolism, causing insufficient suppression of bone resorption. However, Ca-regulating hormones appeared not to be directly related to bone metabolism during the period (average: 39.6 months) after oophorectomy.

Absorptiometry, Photon↗
PubMed1989

[Hyperthermia in malignant tumors of the extremities--experimental heating by a radiofrequency applicator and its clinical significance].

We studied hyperthermia for malignant tumors of the extremities, and obtained the following findings. In osteosarcoma cultured cells from OST (Human) and Dunn (Mouse), proliferation was clearly inhibited on being heated to 42 approximately 43 degrees C. On heat-treating the femurs of pigs, a rise in temperature to 42.5 degrees C or above was observed so that an antitumor effect could be anticipated. Moreover, no abnormal rise in temperature in the tissues surrounding the bone and light microscopy revealed no particular abnormalities. Clinically, a rise in temperature above 42.5 degrees C was observed in the majority of the malignant bone tumors (4 cases of osteosarcoma and 1 case of chordoma) and soft tissue tumors (1 case of epithelioid sarcoma, malignant fibrous histiocytoma, rhabdomyosarcoma, malignant melanoma and osteosarcoma) of which 2 cases were metastatic tumors. Before administration, 7 patients complained of pain, 4 of whom (57%) experienced an alleviation following treatment. Also in 5 (50%) out of 10 cases a shrinking of the tumor was observed and especially, in the case of soft tissue tumors a tendency towards a softening of tumor texture was seen.

Animals↗
PubMed1989

[Effects of alfacalcidol (1 alpha-OH-D3) on post oophorectomy osteopenia as measured by microdensitometry].

The present study included 24 relatively young patients (48.4 years on average) who had decreased bone mineral levels after oophorectomy (severity scores of 4 or above as judged by the MD method), and the efficacy of active vitamin D3 (D3) was assessed according to the mean percentage of change in MD indices. The patients were randomly divided into two groups of 12 cases each, the D3-treated group and the non-treated group. The D3 treatment was given in the form of 1 microgram/day alfacalcidol for 9.67 months on average. Before and after treatment, the MD indices and serum Al-p, calcium and potassium were measured. The non-treated group was observed for 9.92 months on average, and the same parameters were measured before and after the observation period. There were no significant intergroup differences with regard to age, height, body weight, duration after oophorectomy, severity of decreased bone mineral levels and other background factors. In the treated group, MCI and d tended to increase and to decrease, respectively, GSmin and sigma GS/D also tended to increase and GSmax tended to increase (p less than 0.10). In the non-treated group, MCI decreased and d tended to increase, GSmin and GSmax tended to decrease, and sigma GS/D decreased (p less than 0.05). In the intergroup comparison, GSmax increased in the treated group (p less than 0.05) and sigma GS/D also tended to increase more in the treated group (p less than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗