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Biomedical subjects

I Watanabe

Publications and source records attributed to I Watanabe.

At least 487 records · Page 27Linked to original sources

Population of aerobic heterotrophic nitrogen-fixing bacteria associated with wetland and dryland rice.

Nitrogen-fixing activity and populations of nitrogen-fixing bacteria associated with two varieties of rice grown in dryland and wetland conditions were measured at various growth stages during the dry season. Acetylene reduction activities were measured both in the field and for the hydroponically grown rice, which was transferred from the field to water culture 1 day before assay. The activities measured by both methods were higher in wetland than in dryland rice. The population of nitrogen-fixing heterotrophic bacteria associated with rhizosphere soil, root, and basal shoots was determined by the most probable number method with semisolid glucose-yeast extract and semisolid malate-yeast extract media. The number of nitrogen-fixing bacteria was higher in wetland conditions than in dryland conditions. The difference between two conditions was most pronounced in the population associated with the basal shoot. The glucose medium gave higher counts than did the malate medium. Colonies were picked from tryptic soy agar plates, and their nitrogen-fixing activity was tested on a semisolid glucose-yeast extract medium. The incidence of nitrogen-fixing bacteria among aerobic heterotrophic bacteria in association with rhizosphere soil, root, and basal shoots was much lower in dryland rice than in wetland rice.

Journal Article↗

Immunological techniques to identify Azospirillum associated with wetland rice.

Azospirilla associated with wetland rice were isolated and characterized by employing immunodiffusion and immunofluorescence techniques. Antisera against two strains belonging to Azospirillum lipoferum produced at least one heat-labile precipitation band with most isolates of A. lipoferum and A. brasilense. Antisera against two strains belonging to A. lipoferum and one strain belonging to A. brasilense produced one band only with strains of their respective species. Fluorescent antibody reactions with Azospirillum were species specific. Specificity of these antisera and fluorescent antibodies was further demonstrated with bacteria other than Azospirillum.

Agglutination Tests↗

Response of upper airway resistance to rebreathing in the rabbit. The interrupting effect of alpha-adrenergic blockers.

The response of upper airway resistance to rebreathing was studied in 20 rabbits. The upper airway decreased after rebreathing for 60 s, which induced hypercapnia and hypoxia. In the group injected with phentolamine mesylate, 2 mg/kg i.v., the decrease of the upper airway resistance was smaller than before administration. On the other hand, in the group injected with droperidol, 2 mg/kg i.v., this respiratory reflex was completely interrupted. The alpha-adrenergic function of this respiratory reflex is discussed.

Airway Resistance↗

[Laboratory and clinical investigations of cefotiam in surgical biliary tract infections].

Laboratory and clinical comparative investigations with cefotiam (CTM) and cefazolin (CEZ) were performed to confirm efficacy and safety in surgical, biliary tract infections. The following results were obtained. 1) The MICs of CTM against organisms, 20 strains, which were isolated from bile of patients with cholecystitis, were studied, especially those of CTM against E. coli and Klebsiella were 0.2 - greater than or equal to 100 micrograms/ml and 0.1--12.5 micrograms/ml, respectively, considerably lower than those of CEZ. And moreover against CEZ-resistant Proteus morganii and Serratia marcescens, CTM showed potent activities, that is, MIC values, 12.5--50 micrograms/ml and 0.78 microgram/ml, respectively. 2) In cholecystectomized patients, 2 grams of CTM was injected intravenously, followed by determination of bile concentration in gallbladder, common bile duct and concentration of gallbladder and liver tissue about 2 hours after administration. The mean bile concentrations of CTM in gallbladder and common bile duct were 1,213.2 micrograms/ml and 1,287.8 micrograms/ml, respectively. The peak concentration of CTM was 2,919.0 micrograms/ml. The mean concentrations of CTM in gallbladder and liver tissue were 28.5 micrograms/g and 45.7 micrograms/g, respectively. On the other hand, the mean bile concentrations of CEZ in gallbladder and common bile duct were 138.7 micrograms/ml and 128.8 micrograms/ml, respectively. 3) Bile concentrations of CTM was compared with those of CEZ by crossover method. The concentration of CTM was 37.7 micrograms/ml even at 5 or 6 hours after 2 grams intravenously administration. CTM showed extremely higher concentration than CEZ in bile. 4) The clinical effect was studied in 6 cases of surgical, biliary tract infections. The results were excellent in 2 cases, good in 3 cases and poor in 1 case, and the clinical efficacy was 83%. 5) CTM was administered to 6 patients who showed negative to intracutaneous reaction test. Nausea, itching, and eruption were observed in each 1 case after intravenously administration of CTM 2 g, however these adverse reactions disappeared within several hours. Throughout the course of treatment, any unusual laboratory findings related to CTM were not observed.

Adult↗

Structural changes in human pituitary tumor after bromocriptine therapy.

The histological appearance of a prolactin-producing tumor and of a growth hormone-producing tumor after short term bromocriptine therapy was studied in detail using light microscopy with conventional and immunocytochemical methods and using transmission electron microscopy. The findings were correlated with clinical, radiological, and biochemical data. Histological changes consisting of clumping of nuclear chromatin and a marked reduction in cytoplasmic volume due to loss of ribosomes, rough endoplasmic reticulum, and Golgi complexes were observed only in the prolactin-producing tumor. Normalization of elevated serum prolactin levels and reduction in size of the tumor observed in serial computed tomograms correlated with striking histological changes found in the tumor. These changes were interpreted to represent a reversible inhibition of the protein-synthetic machinery of the neoplastic cell. Comparable clinical, biochemical, radiological, or structural changes were not observed in the growth hormone-secreting tumor.

Bromocriptine↗

Enhanced radiation lethality in partially synchronized solid mouse tumors.

We studied the combined effects of local irradiation on in vivo partially synchronized solid mouse tumors. Syngeneic fibrosarcoma cells were transplanted s.c. into the thighs of C3H/He mice. When the tumors grew to 179 cu mm in volume, 1-beta-D-arabinofuranosylcytosine (ara-C) was repeatedly injected i.p. followed by a single injection of vinblastine sulfate at 5 hr after the end of the ara-C treatment. The mitotic indexes increased from 4% in control to 22 to 23% at 5 hr after the ara-C treatment, and the level continued for another 5 hr. Further treatment with vinblastine sulfate after the ara-C injections resulted in more effective accumulation of mitotic cells, i.e., 30% at the sixth hr. The tumor was locally irradiated with a single dose of 3000 rads of gamma-rays at the maximum level of mitotic index. The results indicated a synergistic inhibition of tumor growth and an 84% prolongation of the 50% survival day beyond that of the nontreated control mice.

Animals↗

[General pharmacology of T-1982, a new cephamycin antibiotic].

General pharmacological studies on T-1982 produced the following results. On central nervous system, subcutaneous injection of T-1982 at dose of 2,000 mg/kg hastened the onset of pentetrazole-induced tonic extensor in mice. T-1982 had no effect on spontaneous motor activity, pentobarbital hypnosis, body temperature or EEG in mice or rabbits, and also did not show motor incoordinate, anticonvulsive or analgesic activity in mice at intravenous doses of 250--1,000 mg/kg or subcutaneous doses of 500--2,000 mg/kg. On motor and sensory nervous systems, no effect of T-1982 was noted on spinal reflex, neuromuscular junction, conduction anesthesia or surface anesthesia in rats or rabbits. On respiratory, cardiovascular and autonomic nervous systems, T-1982 caused transient increase of respiratory rate, slight hypotension and transient increase of femoral blood flow in dogs at intravenous doses of 250--1,000 mg/kg. However, it caused a slight hypertensive tendency in rabbits. Heart rate and ECG in dogs or rabbits, blood pressure response to epinephrine, isoproterenol, acetylcholine or histamine in dogs, nictitating membrane in cats and pupil size in mice were not affected after intravenous injection of T-1982. No effect was found on isolated guinea pig atrium or rabbit descending aorta following T-1982 application. On renal function in rats, T-1982 caused an increase of PSP excretion but had no effect on urine volume or electrolytes excretion at intravenous doses of 250--1,000 mg/kg. T-1982 prolonged bleeding time in mice at intravenous doses of 500--1,000 mg/kg, but did not show hemolytic property and inhibitory activity on blood coagulation or platelet aggregation in vitro experiments. Spontaneous movement and tone of isolated stomach, ileum, colon, uterus, vas deferens or trachea and acetylcholine-, histamine-, nicotine- or barium chloride-induced contraction of ileum were not affected following T-1982 application. Intestinal propulsion of barium meal in mice, gastric secretion and carrageenin-induced edema in rats were not affected after intravenous injection of T-1982. T-1982 increased bile secretion in rats dose-dependently at intravenous doses of 31.3--125 mg/kg. The local irritative activity of T-1982 in rats was slightly milder than cefoxitin and moderately milder than cefmetazole after intradermal injection. In conclusion, these results suggest that T-1982 would not cause any adverse effects at its estimated clinical doses of 10--20 mg/kg (500--1,000 mg/man).

Animals↗

[The effects of cue upon selective memorization].

The subjects listened to a list of 21 words read aloud and memorized eight words among them indicated by the cue. In VC (voice-cue) condition, where the change of voice between male and female cued the difference between the to-be-memorized and not-to-be-memorized items, the percentage of correct recall was higher and the number of intrusion-errors was fewer than in NVC (non-voice-cue) condition, where the cue was the sound of chime given immediately before the to-be-memorized item. The results suggest that the physical characteristics of cue facilitate the selective memorization, but do not necessarily support the early-selection theory of attention. Next, in order to confirm Watanabe's (1976) assertion that the transformation of to-be-memorized items into long-term memory and the exclusion of not-to-be-memorized items take place in parallel, the subjects were required to rehearse aloud every word as it was presented. However, it was found that the method of voiced rehearsal was inadequate to test the assertion.

Adolescent↗

Simultaneous Streptococcus and picornavirus infection. Muscle involvement in acute rhabdomyolysis.

Streptococci seldom invade muscle in healthy people with intact integument. However, infection with another agent simultaneously may change this general observation. In a two-week period we encountered dual infections with group A, beta-hemolytic streptococci and a picornavirus in each of two hospitalized patients. Both were acutely ill; one died. Renal failure developed in the patient who survived and rhabdomyolysis was demonstrated in the patient who died. Picornavirus titer increases were demonstrated in the patient who survived, and viral inclusions in muscle cells were demonstrated by light microscopy in necropsy specimens and confirmed by electron microscopy in the second patient. We believe that streptococcal invasion of muscle may be facilitated during an outbreak of certain picornavirus infections.

Acute Disease↗