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Biomedical subjects

S Okuda

Publications and source records attributed to S Okuda.

At least 217 records · Page 12Linked to original sources
PubMed1988

Topographic electroencephalographic studies in a hyperbaric environment--specific reference to high pressure nervous syndrome.

Hyperbaric chamber dives at various equivalent depths below sea level, i.e. 7, 14, 19 and 31 atmosphere absolute (ATA) with helium-oxygen or helium-nitrogen-oxygen have been performed at the Japan Marine Science and Technology Center. A two-dimensional (topographic) display of the scalp EEG was used during simulated underwater experiments to determine; 1) Whether there are any characteristic EEG patterns in high pressure nervous syndrome (HPNS), 2) the relationship between the EEG changes and the compression rate, and 3) the relationship between the EEG changes and the characteristic signs and symptoms of HPNS. A two-way analysis of variance and a distribution analysis technique revealed that the topographic brain patterns depended on the diving depth and indicated the most affected brain areas during compression and decompression. Significant correlations between the diving depth and the EEG potentials were observed at different brain locations. Alpha waves showed a diffuse cortical distribution. Theta wave activity was more localized in the frontal midline region. These waves developed paroxysmally in relatively brief bursts supplanting or intermixing with normal background EEG rhythms. In our subjects, frontal midline theta activity was associated mostly with some of the characteristic features of HPNS, such as a transient episode of laughter or euphoria at depths greater than 21 ATA. An intimate correlation between frontal midline theta wave and laughter was observed. Frontal midline theta waves may be related to emotional activities induced by helium under high pressure. There were significant individual variations in susceptibility and subjective signs and symptoms. The EEG is of great value in studying man's physiological reactions in an undersea environment and also very important in selecting divers who are relatively more tolerant of a severe hyperbaric environment.

Adult↗
PubMed1988

A new method of inhibiting glycolysis in blood samples.

The maintenance of hydrogen ion concentration in blood samples at pH 5.3-5.9 immediately inhibits glycolysis. This effect is due to the inhibition of all glycolytic enzymes, as shown by measurement of various glycolytic intermediates. At the inhibitory pH at 25 degrees C, the glucose content did not decrease over a period of 8 h, but it did decrease by 1.3 +/- 1.1 mg/dl over 24 h.

Adenosine Triphosphate↗
PubMed1988

Effect of cigarette smoking on extent of acid-secreting area and intestinal metaplasia in the stomach.

The association of cigarette smoking and other variables with the extent of the acid-secreting area and intestinal metaplasia were investigated by multivariate analysis. Studies were made by the endoscopic Congo red-methylene blue test developed in our hospital. In this test, acid-secreting areas and areas of intestinal metaplasia could be identified as discolored areas and areas staining blue with methylene blue, respectively. In multivariate analysis, the following variables were associated with a reduction in the size of the acid-secreting area in decreasing order of importance: the smoking index and age. The following factors had little or no influence on the size of the acid-secreting area: sex, and the consumption of aspirin and nonsteroidal, nonsalicylate, antiinflammatory drugs (NSNSAIDs). In general, in patients with a high smoking index, the acid-secreting area was small. Smoking had an influence in both younger and older patients and had more influence in females than in males. Multivariate analysis also shows that the following factors were associated with an increase in the area of intestinal metaplasia in decreasing order of importance: the extent of the acid-secreting area, age, and the smoking index. The following factors had little or no influence on the area of intestinal metaplasia: the consumption of aspirin and NSNSAIDs and sex. In general, in patients with little or no acid-secreting area, the area of intestinal metaplasia was extensive. These findings indicate that smoking is associated with reduction in the size of the acid-secreting area and so in development of intestinal metaplasia.

Adult↗
PubMed1988

Pharmacokinetics of a new angiotensin I converting enzyme inhibitor (delapril) in patients with deteriorated kidney function and in normal control subjects.

Pharmacokinetic properties of a new angiotensin-converting enzyme inhibitor, delapril (CV-3317), which converts to two active metabolites (M-1 and M-2) and one inactive metabolite (M-3) after oral administration, were investigated in six subjects with normal, 10 subjects with slight (SRF), and six subjects with markedly (MRF) deteriorated kidney function. The elimination half-life of M-1 was prolonged significantly in subjects with MRF and that of M-3 was also prolonged in subjects with SRF or MRF. The peak plasma drug concentration, time to reach peak concentration (tmax), and AUC were significantly larger in subjects with SRF and MRF than in normal subjects, except for Tmax in subjects with SRF. In M-2 and unchanged delapril, no difference was observed. The 24-hour cumulative urinary excretion of those metabolites was significantly lower in subjects with MRF than in normal subjects. Plasma angiotensin-converting enzyme activity, suppressed at 4 hours in all subjects, remained significantly low in patients with MRF at 24 hours. Blood pressure was reduced more in subjects with chronic renal failure. It was concluded that delapril is excreted mainly through the kidney and its pharmacodynamics and biologic effects are affected by the renal dysfunction.

Administration, Oral↗
PubMed1988

Diagnosis of simultaneous multiple gastric cancers by the endoscopic Congo red--methylene blue test.

The clinicopathological features of simultaneous multiple gastric cancers, and the accuracy of their diagnosis by routine endoscopic examination were analyzed. In addition, the accuracies of diagnosis of coexisting early gastric cancers by routine endoscopic examination and by the endoscopic Congo red--methylene blue test developed in our hospital were compared. The results showed that multiple cancers occurred frequently in elderly male patients, in patients with early gastric cancer of the flat and elevated types and the depressed type without converging folds, and in patients with advanced cancer of Borrmann type I. These patients frequently have early cancers of the flat or depressed types without converging folds, and advanced cancers of Borrmann type I. The coexisting lesions are very difficult to diagnose by routine endoscopic examination: a correct diagnosis of coexisting early cancers was made in only 28.3% of the cases by routine endoscopic examination. But with the Congo red--methylene blue test, the diagnostic rate was raised significantly to 88.9%. In this test, Congo red and methylene blue are sprayed on the surface of the stomach and are bleached within 2 to 5 minutes on the surface of a tumor, but not on the surface of unaffected mucosa.

Aged↗
PubMed1988

Importance of early initiation of dietary protein restriction for the prevention of experimental progressive renal disease.

The effect of dietary protein restriction on the progress of renal dysfunction was investigated in rats with adriamycin (ADR)-induced progressive glomerular disease. Dietary protein was reduced from 20% (normal diet) to 5% (low protein) immediately after (ADR-0w), 8 weeks (ADR-8w) or 16 weeks (ADR-16w) after the repeated injection of ADR. In the unrestricted (ADR-UR) group rats were fed 20% of protein throughout the 24-week experiment. Massive urinary protein developed immediately after ADR injection and significantly decreased by reducing dietary protein in all the groups (ADR-0w, ADR-8w, ADR-16w). However, plasma protein and serum albumin were low irrespective of the improvement of urinary protein. BUN and serum creatinine were unchanged in ADR-0w and ADR-8w groups, while they were increased in ADR-16w and ADR-UR groups. Glomerular sclerosis and tubular atrophy were much less severe in ADR-0w and ADR-8w than in ADR-16w and ADR-UR groups. The results indicate that dietary protein restriction checks the further progress of renal dysfunction. The importance of the time when protein intake should be reduced is discussed.

Animals↗
PubMed1988

High incidence of glomerular sclerosis in rats subjected to uninephrectomy at young age.

To examine the effect of age on a compensatory renal growth, adaptive renal hemodynamics and renal histology in solitary kidney, unilateral nephrectomy was performed in young rats at 4 weeks of age (group 4-UN) or in adult rats at 10 weeks of age (group 10-UN). Urinary protein was measured every 4 weeks until the 48th week. Serial changes in kidney weight, glomerular filtration rate (GFR), renal plasma flow (RPF) and renal histology were investigated at weeks 4, 8, 24 and 48 after the uninephrectomy. Increase in proteinuria was significantly greater in group 4-Un than in group 10-UN from weeks 32-48 after uninephrectomy. The remnant kidney showed a compensatory enlargement which was more marked in group 4-UN than in group 10-UN at weeks 24 and 48. GFR or RPF in group 4-UN was significantly greater than that in group 10-UN at weeks 4, 8, and 24. Focal and segmental glomerular sclerosis was evident at week 24 or later in the uninephrectomized rats, being more severe in group 4-UN than in group 10-UN at week 48. We conclude that uninephrectomy in young rats leads to augmented compensatory renal growth and glomerular hyperperfusion, resulting in extensive glomerular sclerosis compared to that in adult rats.

Age Factors↗
PubMed1988

Beneficial effect of aluminum hydroxide on progress of adriamycin-induced nephropathy in rats.

To investigate the effect of phosphate binder on adriamycin (ADR)-induced nephropathy, serial changes in renal histology and renal hemodynamics were compared between ADR rats treated with aluminum hydroxide (ADR-AH group) and those without AH (ADR group) for 24 weeks. Urinary protein excretion was less marked in the ADR-AH group than in the ADR group. Serum creatinine in the ADR group increased progressively from week 20, while in the ADR-AH group the increase was less. There were no significant differences in glomerular filtration rate or renal plasma flow between the both groups until week 12 but these parameters decreased to the significantly lower levels at week 24 in the ADR group. Vacuolative degeneration in glomerular epithelium, which was determined as an initial renal lesion, was more marked in the ADR group compared to the ADR-AH group. Glomerular sclerosis and tubulointerstitial changes developed progressively in the ADR group at the later stages. These changes were lessened in the ADR-AH group. In conclusion, AH prevents the progress in ADR-induced nephropathy. The beneficial effects appeared as the preservation of glomerular epithelial cells.

Aluminum Hydroxide↗
PubMed1988

Value of gastric juice carcinoembryonic antigen in identifying high-risk patients for gastric cancer.

The relationship of the level of carcinoembryonic antigen (CEA) in the gastric juice to the extent of intestinal metaplasia and gastric cancer, and clinical values of gastric CEA for identifying high-risk patients for gastric cancer were examined. A significant correlation was found between the levels of gastric CEA and the distribution of intestinal metaplasia. Studies were made by the endoscopic Congo red-methylene blue test developed at our hospital. Gastric CEA levels were significantly higher in patients with localized and diffuse intestinal metaplasia than in those with no intestinal metaplasia. The mean levels of gastric CEA in patients with well-differentiated adenocarcinomas were significantly higher than in those with diffuse intestinal metaplasia. They were also significantly higher in patients with poorly differentiated adenocarcinomas than in patients with no intestinal metaplasia, but not significantly higher than in those with diffuse intestinal metaplasia. Endoscopic follow-up examinations show that gastric cancer was detected in only 1 patient with a gastric CEA level of 10 ng/ml or more, but in none of those with gastric CEA of less than 10 ng/ml, during the average observation period of 4.3 years. These results indicate that gastric CEA is produced both by intestinal metaplasia and well- and poorly differentiated adenocarcinomas, and that gastric CEA is useful in identifying high-risk patients for gastric cancer.

Carcinoembryonic Antigen↗
PubMed1988

Comparison of photodynamic inactivation of experimental stomach tumors sensitized by acridine orange or hematoporphyrin derivatives.

The photodynamic inactivations of Walker carcinosarcoma 256 stomach tumors by the concomitant use of acridine orange (AO) and argon laser, and by the combined use of hematoporphyrin derivatives (HPD) and dye laser were compared. Wistar rats bearing stomach tumors of 4-6 mm in diameter 5-10 days after their implantation were injected intraperitoneally with 40 mg/kg body weight of AO or HPD, and 24 h later their stomach tumors were exposed to argon laser at 488 nm or dye laser at 630 nm, respectively, at an intensity of 15 mW/cm2 for 20 min. Temperature rise was less than 3 degrees C during irradiation. Seven days after irradiation, complete or partial necrosis with sparing of the surrounding mucosa was seen histologically in all rats treated by the two therapy methods. Phase contrast and electron microscopy showed nuclear pyknosis and damage to the inner layer of the nuclear envelope in tumor cells treated with AO and argon laser, while cytotoxicity involved damage to the outer layer of the nuclear envelope and intracytoplasmic organelles in tumor cells treated with HPD and dye laser. This difference between AO and HPD is considered to be a difference in their intracellular localization in tumor cells.

Acridine Orange↗
PubMed1988

Aluminium hydroxide prevents progression in experimental focal glomerular sclerosis.

To investigate the effect of phosphate binding on the progress of chronic renal disease, aluminium hydroxide was administered to rats with focal glomerular sclerosis experimentally induced by adriamycin over a period of 28 weeks (group ADR-AH). The clinical data were examined every 4 weeks and the renal histology at week 28 were compared to those in adriamycin-injected rats without aluminium hydroxide treatment (group ADR). Urinary protein excretion was less marked in group ADR-AH than in group ADR at weeks 8 and 12. Serum creatinine in group ADR started to increase at week 20 and continued to rise until week 28, while in group ADR-AH it increased less, the difference being significant. Serum phosphate was lower in group ADR-AH than in group ADR at weeks 8, 12, 24, and 28. Focal glomerular sclerosis and tubulointerstitial changes were observed in both adriamycin-injected groups regardless of aluminium hydroxide treatment at week 28, although these changes were much less severe in group ADR-AH. There were no differences in body weight and serum albumin between the two groups. We conclude that aluminium hydroxide could prevent the renal deterioration in focal glomerular sclerosis induced by adriamycin without affecting the nutritional state.

Aluminum Hydroxide↗