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Biomedical subjects

T Teshima

Publications and source records attributed to T Teshima.

At least 271 records · Page 15Linked to original sources
PubMed1981

Radioaerosol inhalation lung cine-scintigraphy: a preliminary report.

"Radioaerosol inhalation lung cine-scintigraphy", a cinematographic display of the lungs following radioaerosol inhalation has been found to be extremely helpful not only to the visual assessment of mucociliary clearance in the lungs but also to the setting of regions of interest and to the interpretation and analysis of clearance curves over the regions of interest in the lungs. It is expected that this procedure offers an important means to the study of mucociliary clearance in health and disease in man.

Adult↗
PubMed1981

Effect of isoproterenol on regional pulmonary perfusion and its blockade by propranolol.

Effects of isoproterenol and propranolol on regional pulmonary perfusion were assessed in the dog. In each experiment the right upper lobe was isolated in vivo by a balloon catheter and artificially ventilated with nitrogen, air or 60% oxygen in nitrogen before and after administration of the medicaments listed above. The rest of the lungs kept breathing air spontaneously. Following administration of isoproterenol regional pulmonary perfusion increased in the hypoxic right upper lobe induced by artificial ventilation with nitrogen, but the increase was not observed when isoproterenol was administered following pretreatment with propranolol. Administration of propranolol alone did not induce any change in regional pulmonary perfusion distribution. When artificial ventilation was done in the right upper lobe either with air or 60% oxygen in nitrogen, thus inducing regional less hypoxia or hyperoxia, no change in regional perfusion was observed with any of the medication. Thus isoproterenol reversed regional hypoxic pulmonary vasoconstriction, but its action was blocked by pretreatment with propranolol. Propranolol per se, however, showed no effect on pulmonary vascular responses to the different alveolar oxygen tensions.

Animals↗
PubMed1981

Effect of dopamine on regional pulmonary perfusion.

Dopamine effect on regional pulmonary perfusion in the right upper lobe was studied in 6 dogs in which the lobe was isolated by a balloon catheter and artificially ventilated with nitrogen, air or 60% oxygen in nitrogen, while the rest of the lungs was allowed spontaneous air respiration. Dopamine was administered at the rate of 20 micrograms/kg/min. Each dog served as its own control. There was no change in the regional vascular responses to the different alveolar oxygen tensions in the right upper lobe before and after dopamine administration.

Animals↗
PubMed1980

The translocation inhibitor tuberactinomycin binds to nucleic acids and blocks the in vitro assembly of 50S subunits.

Binding studies were performed with a [14C]-labelled derivative of viomycin, tuberactinomycin 0 (TUM O). TUM O bound to 30S and 50S subunits. The binding component was the RNA, since ribosomal proteins did not bind the drug. Other RNAs such as tRNA, phage RNA (MS2), and homopolynucleotides also bound the drug. Striking differences in the binding capacity of the various homopolynucleotides were found. Poly(U) bound strongly, poly(G) and poly(C) bound intermediately, whereas poly(A) showed a very low binding. DNA also bound TUM O, although with native DNA the binding was only weak. Finally the effects of viomycin on the assembly in vitro of the 50S subunit from E. coli were tested. A very strong inhibition was found: when the reconstitution was performed at 0.5 x 10(-6) M viomycin the particles formed sedimented at about 50S, but showed a residual activity of less than 10%. The inhibitory power of viomycin with respect to the in vitro assembly is more pronounced than that found in in vitro systems for protein synthesis.

Binding Sites↗
PubMed1980

Effect of non-filtered and filtered cigarette smoke on mucociliary clearance mechanism.

Acute effect of a short-term exposure to cigarette smoke on mucociliary clearance mechanism was studied in 69 anesthetized dogs. A tracer material, 99mTc-MAA (macroaggregated albumin), was placed in the right main bronchus near the carina 2 min after completion of exposure and its migration distance on the tracheal mucosa with time was assessed by a scintillation camera, and the mean migrating velocity (MMV) was calculated. The average MMV values were 12.0 +/- 1.0 (mean +/- S.E.) mm/min in the control dogs, while the values were 11.6 +/- 1.5, 8.3 +/- 2.2, 3.3 +/- 0.8, and 4.2 +/- 2.3 mm/min in the dogs which smoked 1, 3, 5 and 8 cigarettes, indicating that there was an inverse correlationship between the number of cigarettes smoked and the MMV values. When cigarette smoke was filtered through a glass fiber filter, the average MMV values were 7.0 +/- 0.5 and 1.3 +/- 0.9 mm/min in the dogs which smoked 5 and 8 cigarettes respectively, suggesting that once the number of cigarettes amounted to eight, even cigarette smoke filtered through a glass fiber filter was as detrimental to the mucociliary clearance mechanism as the non-filtered cigarette smoke.

Animals↗
PubMed1980

Effect of alveolar hypercapnia on regional pulmonary perfusion.

The effect of alveolar hypercapnia under a wide range of alveolar oxygen tensions was assessed in the right upper lobe of the normal dogs and the dogs with the reimplanted right lung. To induce alveolar hypercapnia by artificial ventilation of the right upper lobe, gas mixtures of differing oxygen fractions containing 10% or 20% CO2 were used as exchange gases for the right upper lobe. The concurrent alveolar hypercapnia had little superimposed effect on the regional vascular responses to a wide range of alveolar oxygen tensions in the normal and the reimplanted denervated lung lobe. Under an extreme alveolar hyperoxia, however, the concurrent alveolar hypercapnia somewhat suppressed regional hyperoxic vasodilation and/or recruitment of the pulmonary vascular beds, whereas in the reimplanted lung lobe it potentiated the hyperoxic pulmonary vascular response. The alveolar oxygen tension seems to be the main factor in the regulation of regional perfusion in the lungs.

Animals↗
PubMed1979

Effect of aminophylline on regional perfusion distribution in the lungs.

Using ten normal dogs, the right upper lobe of the lung was isolated in vivo by a balloon catheter and was artificially ventilated with nitrogen, air, 60% oxygen in nitrogen, and 60% oxygen and 20% carbon dioxide in nitrogen, while the rest of the lungs maintained a spontaneous breathing of ambient air. Aminophylline did not show a vasodilating action under severe alveolar hypoxia (PAO2: ca. 40 mmHg); on the contrary, it seemed to potentiate hypoxic pulmonary vasoconstriction. When the regional alveolar oxygen tension became less hypoxic (PAO2: ca. 70 mmHg) or higher than that in the rest of the lungs which spontaneously breathed ambient air, aminophylline showed a definite vasodilating action. Aminophylline also showed a vasodilating action in alveolar hypercapnia in the presence of alveolar hyperoxia.

Aminophylline↗
PubMed1978

Regulation of regional perfusion distribution in the lungs. Experimental model and effect of alveolar pressure.

An experimental model for studying changes in regional perfusion distribution in the lungs of a dog was described. The right upper lobe was separated in vivo from the rest of the lungs by a balloon catheter and gas exchange of the lobe was artificially done asynchronously with the rest of the lungs by using a gas of interest at a prescheduled aveolar pressure. 99mTc-albumin microsphere was the agent of choice for multiple sequential studies in one dog. Alveolar gas composition reached a plateau after the 4th inflation of the right upper lobe. Effect of alveolar pressure on regional perfusion distribution was studied by using nitrogen and air as exchange gases. Perfusion distribution in the right upper lobe was the least at the maximal alveolar pressure of 14 to 19 cm H2O, while it was the greatest at the tidal maximal alveolar pressure of 1 to-1cm H2O with either gas. Alveolar hyperinflation in a localized lung region due to the increase in regional alveolar pressure reduced regional perfusion distribution.

Air↗
PubMed1977

Chemical studies on tuberactinomycin. XV. Total synthesis of tuberactinomycin O.

Tuberactinomycin O, one of the four congeners of the antituberculous peptide tuberactinomycin, was totally synthesized. The beta-ureidodehydroalanine moiety was constructed from beta,beta-diethoxyalanine with excess urea in acidic medium after a cyclization reaction of a pentapeptide was finished. Cyclization was carried out by means of the 1-succinimidyl ester method. To the cyclic pentapeptide, beta-lysine was introduced as the branched moiety and then deprotected to afford tuberactinomycin O which was completely identified with the natural form of the antibiotic.

Antibiotics, Antitubercular↗
PubMed1977

The revised structure of capreomycin.

The total structures of capreomycins IA and IB were determined mainly from the results of the comparative study on the NMR spectra of capreomycins and tuberactinomycins, resulting in a revision of the formerly proposed structure. The beta-lysine residue as a branched part was revealed to be linked with the beta-amino group of the alpha, beta-diaminopropionic acid residue in the cyclic pentapeptide moiety in a different manner than in tuberactinomycins.

Amino Acid Sequence↗