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Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 1,153 records · Page 64Linked to original sources
PubMed1980

Microbial sensors for volatile compounds.

A microbial sensor consisting of immobilized microorganisms, a gas permeable membrane, and an oxygen electrode was prepared for the continuous determination of methyl alcohol. Immobilized methyl alcohol utilizing bacteria was employed for the sensor. The response time of the sensor was within 10 min by the steady-state method. A linear relationship was observed between the current decrease and the concentration of methyl alcohol below 22.5 mg l-1. The selectivity of the microbial sensor for methyl alcohol was satisfactory. Microbial sensors using Trichosporon brassicae for ethyl alcohol and acetic acid are also described. A microbial sensor consisting of immobilized nitrifying bacteria (isolated from activated sludges), a gas-permeable Teflon membrane and an oxygen electrode was prepared for the amperometric determination of ammonia. When the sensor was inserted in a solution containing ammonia, the current decreased to a steady-state with a response time of 4 min. The relationship between the current decrease and the ammonia concentration was linear up to 42 mg l-1. The minimum concentration for the determination was 3.5 mg l-1. The current decrease was reproducible within 4 per cent of relative error. The current output of the sensor was almost constant for over 10 days and 200 assays.

Acetates↗
PubMed1980

Studies on the synthesis of chemotherapeutics. 10. Synthesis and antitumor activity of N-acyl- and N-(alkoxycarbonyl)-5-fluorouracil derivatives.

A number of N-acyl and N-(alkoxycarbonyl)-5-fluorouracil derivatives possessing, for example, benzoyl, o-toluyl, acetyl, propionyl, heptanoyl, ethoxycarbonyl, phenoxycarbonyl, and benzyloxycarbonyl groups as N1 and/or N3 substituents were synthesized, and their antitumor activities were evaluated. The synthesis was achieved by a direct and two-step acylation of 5-fluorouracil and by selective N1-deacetylation of N1-acetyl-N3-substituted-5-fluorouracil under appropriate reaction conditions. Several N3-benzoyl- and N3-o-toluyl-5-fluorouracil derivates and showed significant activity against experimental tumor, and N1-acetyl-N3-o-toluyl-5-fluorouracil was found to be most promising among them. Further investigation revealed 12 to retain higher activity toward various tumors, with lower toxicity and good blood level, than either 1 or FT-207, even for oral administration.

Animals↗
PubMed1980

A clinicopathological study of minute polypoid lesions of the colon based on magnifying fiber-colonoscopy and dissecting microscopy.

Magnifying fiber-colonoscopy reveals that adenoma, minute carcinomatous lesion in an adenoma (which is termed focal carcinoma), and mucosal carcinoma of the colon, each has its own characteristic pit pattern. Inspection by dissecting microscope of resected specimens obtained from subjects whose colonic mucosa had been considered normal, often reveals an abnormal pit pattern of less than 1 mm, and subsequent histologic examination confirms the frequent presence of incipient adenoma. Clinical magnification inspection of areas of colonic mucosa considered normal on the basis of ordinary observation, reveals pit patterns identical to those seen in resected specimens.

Adenoma↗
PubMed1980

Individual differences in blood and breath acetaldehyde levels and urinary excretion of catecholamines after alcohol intake.

Sixty three male Japanese, aged 20-40 yr were evaluated as to the degree of facial flushing following a controlled dose of ethanol either as Japanese rice wine or ethanol 0.4 g kg body weight. Thirty four subjects responded with overt facial flushing. The acetaldehyde levels in blood and expired air were significantly higher in the flushing group without a change in ethanol elimination rate. Urinary excretion of Vanilmandelic acid (VMA) and 3 methyoxy-4-Hydroxyphenylglycol (MHPG) are reported.

Acetaldehyde↗
PubMed1980

24-hour rhythm of human plasma noradrenaline and the effect of fusaric acid, a dopamine-beta-hydroxylase inhibitor.

A 24-hour of basal noradrenaline (NA) levels in normal human plasma in the supine position was observed; higher NA levels during daytime and lower NA levels at night, especially early in the morning. This pattern of the 24-hour rhythm of plasma NA levels was similar to that of serum dopamine-beta-hydroxylase (DBH) levels. After oral administration of fusaric acid, a DBH inhibitor, the rhythm changed, and plasma NA levels increased at 3 h and returned to the initial level at 23 h. In contrast, plasma DBH activity was markedly inhibited during 23 h after fusaric acid administration.

Adult↗
PubMed1980

Differential effects of alpha-methyldopa, clonidine and hydralazine on norepinephrine and epinephrine synthesizing enzymes in the brainstem nuclei of spontaneously hypertensive rats.

Repeated administrations of clonidine to spontaneously hypertensive rats (SHR) markedly lowered dopamine beta-hydroxylase (DBH) activity in the locus coeruleus (LC) and increased it in the spinal intermediolateral cell column (IML), while alpha-methyldopa tended to lower the enzyme activity in the medullary nucleus tractus solitarii (NTS) and A1 cell areas. Clonidine-induced inhibition of 3H-norepinephrine binding to crude cerebral membranes of SHR or Kyoto Wistar rats (KWR) as a measure of alpha-receptor agonist activity was 7 times greater than that of (+/-)alpha-methyl-(+/-)-norepinephrine. Clonidine and hydralazine significantly lowered phenylethanolamine N-methyltransferase (PNMT) activity elevated in the nucleus hypothalamicus posterior (NHP) of SHR to the level of KWR, and both drugs or alpha-methyldopa consistently increased PNMT in the nucleus paraventricularis (NPA). Peripherally active hydralazine also increased PNMT activity in the NTS, and antagonized the activity elevated in the A1 cell area of SHR to the level of KWR. In conclusion, clonidine selectively lowers DBH activity in the LC, while alpha-methyldopa appears to decrease the enzyme activity in the medullary NTS and A1 cell areas, suggesting different sites of action of both drugs. The decreased DBH activity in these nuclei may be related to stimulation of respective alpha-noradrenergic receptors. Elevating effects of all three drugs on PNMT activity in the NPA may be due to decreased baroreceptor afferent impulses to the nucleus after a fall in blood pressure.

Animals↗
PubMed1980

Synthesis and structure-activity relationships of 7 beta-[2-(2-aminothiazol-4-yl)acetamido]-cephalosporin derivatives. III. Synthesis and antibacterial activity of 7 beta-[2-amino-2-(2-aminothiazol-4-yl)acetamido]cephalosporins.

New derivatives of 7 beta-[2-(2-aminothiazol-4-yl)acetamido]cephalosporins having amino group at the 2-position of the 7-acyl moiety were synthesized in the hope that they would show improved antibacterial activity. Some of these compounds (XXa, XXd, XVb) showed improved activity against Enterobacter cloacae. Replacement of the annular amino group by a methyl group caused loss of activity.

Bacteria↗
PubMed1980

[Results of application of cefoperazone to pediatric infections (author's transl)].

Cefoperazone (CPZ) was studied clinically and the following results were obtained. The drug was administered to 21 cases of bacterial infections; respiratory tract infection (17), lymphadenitis (1), urinary tract infection (1), enterocolitis (1) and purulent meningitis (1). The daily dose was 50 approximately 125 mg/kg. The drug was given by one-shot intravenous injection, 3 approximately 4 times a day and the duration of administration was from 3 approximately 18 days. The overall efficacy rate was 81.0%, i.e., excellent in 11 cases, good in 6 cases, moderate in 2 cases and poor in 2 cases. CPZ was potent in the treatment of ampicillin-resistant Haemophilus influenzae meningitis. One patient developed exanthema. No other serious side effects were observed.

Adolescent↗
PubMed1980

Follow-up ten years after corticosteroid therapy for chronic active hepatitis type B.

Follow-up studies were conducted on chronic liver disease patients treated 10 years previously with corticosteroid (CS), Hbs antigen (HbsAg) was measured in previously collected paraffin embedded liver sections by enzyme-labelled antibody technique. Of 57 cases examined, 38 cases were treated with CS or immunosuppressive agents and 19 cases were not treated with CS (control group). -- Two deaths occurred in the CS-treated group and 4 in the non-CS treated group. These patients were diagnosed as either the 2B type (severe activity) of chronic aggressive hepatitis (CAH) or as having liver cirrhosis. One death was found in the 10th year due to hepatocellular carcinoma in a chronic persistent hepatitis (CPH) patient with HBsAg diffusely distributed in liver tissue. No significant difference was found in the rehabilitation rate in HBsAg negative cases of the CS group versus the control group. In positive cases, the rehabilitation rate was found to be 66.7% in the CS group compared with 0% in the non-CS group.

Adrenal Cortex Hormones↗
PubMed1980

[Double-blind comparison of L-keflex and cephalexin (Keflex) in dental infections (author's transl)].

In order to evaluate efficacy and safety of L-Keflex (granule form of sustained release cephalexin), a double blind study comparing it with Keflex (capsule of regular cephalexin) was conducted in dental infections. Evaluable cases in adults for efficacy of the drugs were 196 consisting of 97 for L-Keflex and 99 for Keflex. Those in children were 19 (8 for L-Keflex and 11 for Keflex). There were no significant differences in background of the patients and severity of the diseases between both groups (L-Keflex and Keflex groups). The daily doses used in both groups were 1,000 mg in adults and 500 mg in children, respectively. The dose was given in two divided doses for L-Keflex group and in four divided doses for Keflex group. Following are evaluation by the committee members for the study: Adults 1. Clinical response rate at final therapy day was 93.8% in L-Keflex group and 92.9% in Keflex group, showing no significant difference between both groups. 2. No significant difference in severity of subjective and objective symptoms between both groups was observed at each therapy day. 3. Side effects were found in 6.7% of 105 patients receiving L-Keflex and in 5.6% of 107 patients with Keflex, and there was no significant difference between both groups. As the side effects, gastrointestinal symptoms, rash and itching were observed, but no any other side effects were found in both groups. Children 1. As shown in the above, number of the cases enough to evaluate statistically was not obtained, but all of both groups clinically responded to the drugs. 2. As for side effects diarrhea was observed in only one patient of Keflex group consisting of 12 patients. In the patient, however, discontinuation of the drug was not required and the side effect disappeared during the therapy. From the above results, L-Keflex (granule) is judged to have more convenience than Keflex (capsule) in that (1) it can be administered with b.i.d. regimen and (2) it can be easily taken in dental patients such as patients having difficulty in opening mouth of swallowing pain.

Adolescent↗