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Biomedical subjects

H Takeda

Publications and source records attributed to H Takeda.

At least 667 records · Page 37Linked to original sources
PubMed1979

Rapid ATP assays in perfused mouse liver by 31P NMR.

31P NMR was used to continuously monitor ATP and inorganic phosphate levels in perfused mouse liver. Under "optimal" conditions, the time resolution of the technique was approximately 1 min. In the absence of any metabolic perturbations the ATP level remained constant for at least 2 hr and decreased by only approximately 20% in 18 hr. Both ATP and inorganic phosphate levels responded to alterations in the oxygen supply to the liver. The half-time for this response was approximately 1 min, and the response to short periods of hypoxia or ischemia was partially reversible. The addition of insulin caused only a minor decrease in the ATP level but significantly decreased the rate of response of ATP and phosphate levels to hypoxia and ischemia.

Adenine Nucleotides↗
PubMed1979

Correlation between the physical properties of dietary fibers and their protective activity against amaranth toxicity in rats.

The mechanism(s) by which dietary fiber (DF) exerts beneficial effects on the growth of weanling rats fed toxic doses of amaranth (Food & C Red No. 2) was investigated. When crude DF (GDF) prepared from the roots of edible burdock (Arctium lappa L.) were added at graded levels to a purified basal diet supplemented with amaranth (control), growth was improved with increaseing GDF level up to and above that of the basal diet-fed group. The correlation equation obtained between the dietary percentage level of GDF (X) and the protective activity (Y) expressed as (difference in body weight gains between rats fed test and control diets) X 100/(difference in body weight gains between rats fed basal and control diets) was Y = 32.6 + 86.9 logX (r = 0.98). The comparative activities at the 5% level of various DF prepared from GDF decreased in the order of holocellulose, neutral-detergent fiber, GDF, crude fiber and acid-detergent fiber. Cellulose from cotton fiber had no activity. The activity was intimately related to their water-holding capacity (WHC) and settling volume in water (SV) (f = 0.90 and 0.96, respectively), but not to the capacity to bind amaranth. The correlation showed a saturation phenomenon quite similar to the equation described above in respect of GDF level. At the 10% level, even cellulose which has a low SV, showed protective activity similar to that of 3% GDF. From these and other results, it was concluded that the protective activity of various DF mainly depends on their physical properties such as SV or WHC.

Amaranth Dye↗
PubMed1979

Noninvasive recording of His-Purkinje activity in patients with complete atrioventricular block. Clinical application of an "automated discrimination circuit".

In seven patients with complete atrioventricular (AV) block, His bundle electrograms (HBEs), standard ECG recordings, bipolar esophageal ECGs and highly amplified, filtered, bipolar chest lead ECGs were simultaneously recorded. The filtered chest lead ECG was averaged to determine His-Purkinje activity (HPA). A simplified device, the "automated discrimination circuit," was used to selectively eliminate the superimposed atrial and ventricular potentials that are characteristic of complete AV block and unsuitable for signal averaging. The processed chest lead ECG was amenable to conventional techniques of signal averaging. In four patients with block proximal to the AV node diagnosed by HBE, there was no activity after the P wave in the surface-averaged ECGs. HPA was consistently recorded before the QRS in the surface-averaged ECG. The measurements of the HV and HPA-V intervals were very close, with a difference of less than 2 msec. Three patients with block distal to the His bundle by HBE showed a loss of electrical potential before the QRS in the surface-averaged ECG, but had a consistent HPA after the P waves. The P-HPA intervals coincided well with PH intervals, with a maximal difference of 5 msec.

Action Potentials↗
PubMed1979

[Pharmacological effects of dobutamine and several catecholamines on various smooth muscles (author's transl)].

Pharmacological effects of dobutamine (DOB), a positive inotropic drug, on smooth muscles were compared with those of catecholamines such as norepinephrine (NE), epinephrine (E), isoproterenol (ISO) and dopamine (DA). DOB acted as a partial agonist and simultaneously as an antagonist on alpha-adrenergic receptors in the thoracic artery. Large doses of DOB induced uterine contraction in rabbits, but antagonised the contraction of the vas deferens of guinea pigs, as was induced by electrical stimulation. However, DOB showed a potent activity, similar to that seen with NE or E as an alpha-adrenergic agonist, on the portal vein. Doses of DOB required to produce a relaxation in the trachea of guinea pigs both in vitro and in vivo were 1/250 and 1/600 of ISO, respectively, and were considerably less regarding inhibition of uterine motility in rats. Inhibiting activity of DOB on the transport rate of intestinal contents in mice and gastro-intestinal motility of rabbits was much less than the activity seen with ISO, E and NE. Spasmolytic activity of DOB was also less than that of ISO, NE and E, but was more than that of DA. It is concluded that DOB is a more selective beta 1-agonist than ISO because of its weaker activity on alpha- and beta 2-receptors. The alpha-agonist activity of DOB in the portal vein was however, potent.

Animals↗
PubMed1978

Clinical study on gastric secretion with special reference to pepsin secretion.

The stimulating effect of AOC-tetragastrin, caerulein, Histalog and secretin on human gastric acid and pepsin secretion was studied in gastric ulcer patients. The pattern of gastric acid and pepsin secretion after the administration of caerulein was closely resembled to that of gastrin. Slight increase of pepsin secretion after gastrin or caerulein could be based on "wash-out" action caused by the increase of acid secretion after the stimulants. Stimulating effect on gastric pepsin secretion of histalog and secretin would be independent of gastric acid secretion.

Ceruletide↗
PubMed1978

Association of virus specific replicative ribonucleic acid with nuclear membrane in chick embryo cells infected with japanese encephalitis virus.

Using high resolution electron microscopic autoradiography and velocity sedimentation, RNA synthesis was examined in chick embryo cells infected with Japanese encephalitis virus (JEV). RNA was labelled with 3H-uridine for 5 min or 10 min at 15 h after infection in the presence of actinomycin D and D-glucosamine. Microautoradiography showed significantly numbers of silver grains on the nuclear membranes of 5 min pulse-labelled thin cell sections. The RNA species in membrane fractions obtained from the nucleus and cytoplasm of the infected cells were analysed by sucrose density gradient sedimentation. Radioactive 23S replicative form RNA and 8-12S RNA were obtained from the outer membrane fractions of the nuclear envelope. Labelled 42S virus RNA was obtained from the fractions containing large vesicle membranes and plasma membranes. These results suggest that JEV-RNA synthesis is initiated in the perinuclear region in close association with the outer membranes of the nuclear envelope.

Animals↗
PubMed1978

Heterogeneity of oxygen delivery in normoxic and hypoxic states: a fluorometer study.

An on-line, real-time histogram display of heterogeneity of oxygen delivery to perfused and in situ organs is afforded by a flying-spot fluorometer that provides excitation for either oxidized flavoprotein of the mitochondrial space or reduced pyridine nucleotide of mitochondrial and cytosolic spaces. Emission from the two fluorochromes is acquired at 10(4) to 10(5) data points/s and histograms of the fluorescence intensity versus the number of occurrences of that intensity are displayed at 1--10 times per second. The histograms show alterations of the intensity and of the degree of heterogeneity of the redox states of perfused heart with model coronary occlusion, of perfused and in situ rat liver, and of rat and gerbil models of stroke. The percentage change of oxygen delivery to the intracellular space can be calculated from the areas under the histogram.

Brain↗
PubMed1978

The metabolism of digitoxin in hepatic cirrhosis of human subjects.

Digitoxin, 1 mg, was orally administered to 12 cirrhotic patients (the 6 in a clinically compensated and the 6 in a decompensated state) and their serum concentrations were measured at 6 hours and everyday through 7 days by radioimmunoassay. The serum half-life of digitoxin in these groups and normal subjects, determined from the serum concentrations, was as follows: 4.7 +/- 0.55 days for controls, 4.9 +/- 0.45 days for the compensated group and 5.3 +/- 0.35 days for the decompensated group. No statistically significant difference could be found in half-life among these groups. (P less than 0.2). The same dose of digitoxin was orally administered to 6 cirrhotic patients and 6 control subjects and their left ventricular systolic time intervals, LVET and QS2, were determined at 6 hours and every morning for 7 days. Cardiac responses, exhibited by decrease in the systolic time intervals, in both control subjects and cirrhotic patients dissipated in fair parallel during the ensuing 4 days and returned to base line level by 5 days. From these both biological half-life and physiological effect, it may be concluded that overall metabolism of digitoxin in cirrhotic patients is not disturbed.

Administration, Oral↗
PubMed1978

Adrenergic innervation and contractile activity of the mesotubarium superius of the rabbit oviduct.

Various patterns of spontaneous contractile activity were observed in the mesotubarium in vitro, but generally the frequency was lower and the amplitude was higher in the contractions than in those of the spontaneously motile oviduct. Contractile responses to norepinephrine occurred at concentrations higher than 10(-8) M. Twitch-like contractile responses were produced by field stimulation of 1 msec, 1-30 HZ and 100 V for 10sec. Responses to norepinephrine and electrical stimulation were inhibited by phentolamine or phenoxybenzamine, but were not affected by propranolol. Spontaneous contractile activity of the mesotubarium was diminished but the tonus was not affected by isoproterenol. These results suggest that the responses of the mesotubarium to norepinephrine and electrical stimulation are mainly related to the alpha-receptor rather than to the beta-receptor component.

Adrenergic Fibers↗
PubMed1978

Ultrasono-cardiographic diagnosis of the prolapsed mitral valve.

The characteristic ultrasono-cardiographic (UCG) findings of prolapsed mitral valve were studied in 9 cases by means of ultrasonocardiotomography (UCT). The changes in degree and shape of the prolapsed valve were examined and the leaflet involved was identified. Of the 9 cases, 5 had prolapse of anterior, 3 had that of posterior leaflet and 1 had both. In all cases with midsystolic click and late systolic murmur or pansystolic murmur with late systolic accentuation, the prolapse of anterior leaflet was observed on UCT, and though UCG disclosed midsystolic buckling it was difficult to determine the exact timing of the prolapse by UCG alone. In the cases with rheumatic mitral regurgitation, the prolapse of posterior leaflet and the ballooning of anterior leaflet could easily be found on UCT, but the detection of the above-mentioned 2 findings was difficult by UCG alone. Three of the 9 cases were found to have prolapse of posterior leaflet by left ventriculography, whereas these 3 had prolapse of anterior leaflet on UCT. Hence, the diagnosis of prolapsed mitral valve based on the cineangiography may require re-evaluation.

Adolescent↗