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Biomedical subjects

I Watanabe

Publications and source records attributed to I Watanabe.

At least 289 records · Page 16Linked to original sources
PubMed1989

Selective decrease in lysis of old thrombi after rapid administration of tissue-type plasminogen activator.

The safety of thrombolytic therapy of acute myocardial infarction could be improved if a method were developed to dissolve fresh occlusive coronary thrombus without simultaneously dissolving hemostatic thrombi outside the coronary arteries. This study is based on the assumption that, in a patient with evolving acute myocardial infarction, hemostatic thrombi are likely to be older than the thrombus responsible for occlusion of the coronary artery. It explored whether the relative rates of lysis of fresh and old thrombi could be influenced by the rapidity of recombinant tissue-type plasminogen activator (rt-PA) administration. In each of 17 dogs, two 1 h and two 24 h old thrombi were produced by inserting copper coils into both jugular and both femoral veins. After 24 h and 1 h, respectively, the coils with the thrombi were removed, weighed and inserted into the adjacent carotid and femoral arteries. A 1 mg/kg body weight dose of rt-PA was given either over 180 or over 30 min. The coils were removed and weights of the residual thrombi determined at the end of the 180 min infusion (Group I), at the end of the 30 min infusion (Group IIA) and 45 min after the 30 min infusion (Group IIB). The 24 h old thrombi were lysed significantly less than the 1 h old thrombi in all three experimental groups: 53.9 +/- 4.8% (mean +/- SE) versus 86.1 +/- 2.5% in Group I (p less than 0.001), 16.6 +/- 3.5% versus 65.2 +/- 6.0% in Group IIA (p less than 0.001) and 21.6 +/- 5.4% versus 91.7 +/- 1.7% in Group IIB (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Simultaneous measurement of cytosolic free calcium concentration and cell circumference during contraction, both in a single rat cardiomuscular cell, by digital imaging microscopy with indo-1.

We have developed a novel system using digital imaging microscopy with indo-1 to measure the cytosolic free calcium concentration [( Ca2+]i). The method is particularly suitable for measuring the rapid change in [Ca2+]i in relation to the cell motion. With this system, we made the first successful simultaneous measurement of [Ca2+]i and cell circumference during contraction in an electrically stimulated single rat ventricular myocyte. It was found that the level of [Ca2+]i was elevated during contraction, and that the onset and peak time of the calcium transient preceded that of the decrease in circumference.

Animals↗
PubMed1989

Nitrile hydratase of Rhodococcus sp. N-774. Purification and amino acid sequences.

The nitrile hydratase of Rhodococcus sp. N-774 was purified and crystallized. The enzyme is composed of two different subunits (molecular masses: subunit alpha, 28,500 Da; subunit beta, 29,000 Da). The amino-terminal amino acid sequence of each subunit was determined. There is no sequence homology between the two subunits, suggesting that the peptides originate from different cistrons. The activity of the purified enzyme did not decrease during incubation in the dark, whereas it gradually decreased in intact cells.

Amino Acid Sequence↗
PubMed1989

Survival of Azorhizobium caulinodans in the Soil and Rhizosphere of Wetland Rice under Sesbania rostrata-Rice Rotation.

The survival of indigenous and introduced strains of Azorhizobium caulinodans in flooded soil and in the rice rhizosphere, where in situ Sesbania rostrata was incorporated before the rice crop, is reported. The azorhizobia studied were both root and stem nodulating. In a pot experiment, two crop cycles each of inoculated and noninoculated Sesbania-rice were compared with two crop cycles of flooded fallow-rice. In a field experiment, the effect of repeated incorporation of in situ S. rostrata in the Sesbania-rice sequence was studied. Soils in which inoculated S. rostrata was incorporated contained about 3,000 times more azorhizobia than did soils in the flooded fallow treatment and about 50 times more azorhizobia than did soils in the noninoculated Sesbania treatment. Azorhizobial numbers in the inoculated Sesbania treatment declined toward rice harvest but remained much higher than in the flooded fallow-rice treatment. Repeated incorporation of S. rostrata increased the population density of indigenous soil azorhizobia, whereas the population of inoculated strain ORS571 (Str Spc) declined to an undetectable level; this finding suggested low competitiveness by the introduced strain. In the incorporated Sesbania treatment, the rice rhizosphere harbored significantly more A. caulinodans and supported higher nitrogenase activity per plant than did the rhizosphere of the flooded fallow-rice treatment. Sterile rice seedlings inoculated with A. caulinodans showed nitrogenase activity comparable to that of seedlings inoculated with Azospirillum lipoferum 34H, a rice root isolate. Rhizobia from Sesbania aculeata, Sesbania sesban, a Trifolium sp., and Vigna unguiculata did not support appreciable nitrogenase activity.

Journal Article↗
PubMed1989

Effect of polyethylene glycol-electrolyte lavage solution on intestinal microflora.

The bacterial flora of colonic aspirates taken after oral administration of a polyethylene glycol-electrolyte lavage solution to patients undergoing colonoscopy was analyzed by standard bacteriological methods and DNA hybridization techniques. The data were compared with those for normal feces collected from the same patients the day before treatment. The results indicate that the bacterial composition of feces differs from individual to individual but is not altered by the oral intake of a polyethylene glycol-electrolyte lavage solution. This pilot study demonstrates that routine colonoscopy aspirates taken after standard colonoscopy preparation accurately reflect the microflora of feces and therefore may be used in large-scale epidemiological studies.

Bacteria↗
PubMed1989

Epiphytic Occurrence of Azorhizobium caulinodans and Other Rhizobia on Host and Nonhost Legumes.

A large population of Azorhizobium caulinodans was present on Sesbania rostrata; up to 5 x 10 cm were found on leaves and fewer were found on flowers. Although A. caulinodans was also present on the leaves of Sesbania aculeata (nonhost), the populations were much smaller than that observed on S. rostrata. The population of S. aculeata rhizobia on host leaves was less than 30 cm, and their presence on host flowers was sporadic. Aeschynomene afraspera and Aeschynomene aspera rhizobia, which are profusely stem nodulating, were found on the leaves of host and nonhost plants and on the flowers of host plants, but, Aeschynomene pratensis and Aeschynomene sensitiva rhizobia were not found on the leaves and flowers of host plants.

Journal Article↗
PubMed1989

Oligonucleotide probe for detection and identification of Campylobacter pylori.

We have developed a novel and practical DNA-RNA hybridization assay for the detection and identification of Campylobacter pylori in the gastric mucosa. This technique utilizes a [32P]ddATP-labeled synthetic oligonucleotide probe complementary to a nucleotide sequence present in C. pylori 16S rRNA. This probe is very sensitive and reacted with all 23 strains of C. pylori tested. It is also highly specific, since there was no cross-reactivity with the heterologous organisms Campylobacter coli, C. fetus subsp. fetus, C. jejuni, and C. laridis or with Escherichia coli. Hybridization of the oligonucleotide probe with C. pylori RNA was completely inhibited by treatment of the membrane filters with RNase but not DNase. Although a gastric mucosa tissue homogenate slightly inhibited the hybridization, as few as 10(4) C. pylori cells could be detected even in the presence of 5 mg of gastric mucosa. Gastric biopsy specimens obtained from patients referred for upper gastrointestinal tract endoscopy were tested for C. pylori infection by direct oligonucleotide hybridization, and the results were compared with those of bacteriological cultures, the urease test, and histological observations. A comparison of the urease test and the oligonucleotide hybridization results showed an excellent correlation between the two methods. The clinical usefulness of this oligonucleotide-RNA hybridization method is discussed.

Campylobacter↗
PubMed1989

The pattern electroretinogram in glaucoma: an evaluation by relative amplitude from the Bjerrum area.

A new concept for evaluating the pattern electroretinogram (PERG) in glaucoma and its clinical application are described. The PERG was elicited by two different stimulus fields, namely, the whole central retinal area with a radius of 18 degrees and the paracentral ring area between the radius of 10 degrees and 18 degrees. The amplitude of the PERG for each stimulus field and the ratio of them were analysed for 30 patients with glaucoma or ocular hypertension. Among these only a small number of eyes were detected as abnormal when we evaluated the amplitude itself either with the central stimulus or the paracentral ring stimulus, whereas the ratio of the two values was below normal in some cases of advanced glaucoma. We conclude that the ratio of the paracentral to central PERG is useful for detecting glaucoma.

Adolescent↗
PubMed1989

Effects of verapamil and propranolol on changes in extracellular K+, pH, and local activation during graded coronary flow in the pig.

The beta-adrenergic and calcium channel blocking agents are known to reduce heart rate and alter myocardial contractility. More recent evidence suggests that both agents affect the metabolic consequences of ischemia, independent of their effects on heart rate and contractility. We used a low-flow model of ischemia in swine with heart rate held constant by atrial pacing. Blood was shunted from the carotid artery to the left anterior descending coronary artery through a controlled-flow roller pump to assess the threshold flow for the rise in extracellular potassium ([K+]e) and fall in extracellular pH (pHe) associated with ischemia during control situations and after the administration of either propranolol or verapamil. We also measured the changes in activation delay and contractility associated with graded flow reductions in the presence and absence of these drugs. We found that when heart rate is held constant, 1) verapamil shifts the threshold flow for [K+]e and pHe to lower levels, but propranolol does not; 2) verapamil lessens activation delay, while propranolol aggravates the delay; and 3) verapamil reduces afterload and selectively depresses contractility in the reperfused ischemic zone. We conclude that the calcium channel blockers and the beta-adrenergic-blocking agents have different effects and possibly different modes of action and should not be considered interchangeable when evaluating therapeutic options for patients with ischemic heart disease.

Adrenergic beta-Antagonists↗
PubMed1989

Evaluation of mitochondrial function by measuring the heat production in state 3 and state 4 respiration.

Using a microcalorimetric method, we have measured the heat production in states 3 and 4 respiration of a mitochondrial preparation from rat heart ventricle. Adenosine triphosphate production in state 3 respiration was also determined for the same preparation after heat production was measured. In Tris-buffered solution with pyruvate and malate used as substrates, the total heat production in states 3 and 4 respiration for a 10-min reaction period were about 709 and 207 mJ/mg of mitochondrial protein, respectively. 2,4-Dinitrophenol, an uncoupler of mitochondrial oxidative phosphorylation, increased the heat production in both states 3 and 4 respiration. On the other hand, antimycin A1, an inhibitor of the electron transport system, decreased the heat production in both states. When ventricle mitochondrial dysfunction was induced by the in vivo administration of a high dose of isoproterenol, heat production was increased in state 4 respiration. These results indicate that the calorimetric method can be used to evaluate the mitochondrial function.

Animals↗
PubMed1989

Differential vasodilator effect of nitroglycerin on systemic capacitance and resistance vessels in anesthetized dogs, and the mechanism of its action--a study by measuring mean circulatory pressure and total peripheral resistance.

The aim of our studies was to examine if the baroreceptor reflex induced by intravenous injection of nitroglycerin (NG) nearly nullifies the vasodilator action of NG on the systemic capacitance vessels in dogs anesthetized with pentobarbital. We performed total spinal anesthesia (TSA) in open-chest dogs to eliminate the baroreceptor reflex. Dogs in which mean blood pressure (MBP) was maintained at about 100 mmHg by continuous intravenous infusion of epinephrine formed the TSA 100 group, and those in which MBP was maintained at about 70 mmHg formed the TSA 70 group. Dose-response curves relating 5-6 different doses (0.8 to 200 micrograms/kg) of intravenous NG, to changes in mean circulatory pressure (% delta MCP) and to changes in total peripheral resistance (% delta TPR), were constructed. These data were compared with those from untreated dogs. In addition, we also studied plasma catecholamine (CA) concentrations before and after the intravenous injection of NG. (1) There was no significant difference in the dose-response curves of NG for % delta TPR between the 3 groups. (2) There was no significant difference in the dose-response curves for % delta MCP between the 2 TSA groups. However, there was significant difference in the dose-response curves for % delta MCP between the TSA groups and the untreated dogs. The dose-response curves for % delta MCP in the TSA groups shifted upwards as compared with that of the untreated dogs. (3) In the TSA 100 group, there was no significant increase in the plasma CA concentrations with 100 micrograms/kg of NG. In the untreated group, intravenous injection of 12.5 micrograms/kg and 100 micrograms/kg of NG caused a dose-related fall in MBP and a dose-related rise in the plasma norepinephrine and epinephrine concentrations. Our results suggest that the vasodilator action of NG on the systemic capacitance vessels in the untreated dogs was counterbalanced partly by the vasoconstriction produced by the baroreceptor reflex, with its direct vasodilator effect masked when the hypotensive doses of NG were given acutely.

Anesthesia, Spinal↗
PubMed1989

[Effect of different kinds of toothbrushes on toothbrushing pressure and plaque removal in the scrubbing method of toothbrushing (5). Toothbrushes with nylon bristles arranged in different lengths along the toothbrush shank and with different types of toothbrush bristle tip].

The purpose of this study (Report 5) was to investigate the effect of difference in the length of toothbrush shank and type of tip of toothbrush bristle on toothbrushing pressure and plaque removal in the scrubbing method. Four kinds of toothbrushes which were different in length of shank (30 mm, 40 mm) and type of bristle tip (round type, tapered type respectively) were used in this study. Referring to the results of our previous reports (1-4), the dimension of new toothbrushes were determined as follows, nylon bristles: 40 mm long and 0.20 mm in diameter, brushing surface: 30 mm long, bristles: 3 rows with 26 tufts, and a straight handle. Twelve subjects participated in this experiment. Plaque scores were measured before and after toothbrushing. Then plaque removal rates were calculated. Toothbrushing pressure was determined using Watanabe's method. The average toothbrushing pressure of the toothbrush with a 40 mm long shank (301.6 +/- 84.1 g/cm2) was higher than that with a 30 mm long shank (294.7 +/- 74.8 g/cm2), and that with a tapered bristle type (316.7 +/- 90.4 g/cm2) was higher than that with a round type bristle (279.6 +/- 61.7 g/cm2). However statistically significant differences were not found among the four toothbrushes in brushing pressure and in plaque removal on total teeth surfaces and on distal surfaces of the most posterior teeth (P less than 0.05; two-way ANOVA).

Dental Plaque↗
PubMed1989

Intradiploic arachnoid cysts. Report of two cases.

Two patients are presented in whom cranial arachnoid cysts developed as diverticuli of the arachnoid membrane through small defects in the dura mater, eroded through the inner table, expanded within the diploe, and eroded the outer table of the skull. Based on observations at the time of surgery and the histological examination of these lesions, it is proposed that they are congenital in origin. Previously reported cases of "traumatic arachnoid cyst without fracture," "intradiploic cerebrospinal fluid fistula," and "middle fossa pitholes" appear to represent the same pathological process as the lesions reported in this paper. It is proposed that "intradiploic arachnoid cyst" is the most appropriate term by which these lesions should be described.

Aged↗
PubMed1989

[Inputs to cerebellar dentate nucleus from the pontine nucleus in the cat].

We have reported before that there are excitatory inputs to the cerebellar dentate nucleus (DN) from the cerebral cortex. This study was performed to examine whether the pontine nucleus (PN) and the nucleus reticularis tegmenti pontis (NRTP), which are among the precerebellar nuclei that relay inputs to the cerebellar cortex, also play a role as the relay nucleus of the excitatory input to the DN. In anesthetized cats, we stimulated the PN and the NRTP, and recorded intracellular potentials from DN neurons. Short-latency EPSPs were evoked from these nuclei and their latencies ranged from 1.1 to 3.6 msec, which are compatible with monosynaptic latencies. Systematic stimulation of the PN and the NRTP with weak stimulus intensities revealed that low-threshold foci for monosynaptic EPSPs in each cell were localized in the PN or the NRTP or both. We could not find monosynaptic inputs from the red nucleus and by recurrent collaterals of the dentate output neurons. Accordingly, the possibility was excluded that the monosynaptic EPSPs evoked from the PN and the NRTP were evoked by inadvertent current spread to the descending axons of DN neurons in the brain stem. The conditioning-testing stimuli of the cerebral peduncle and the PN or the NRTP yielded spatial facilitation. This result showed that the input from the cerebral cortex to the DN was relayed by way of the PN or the NRTP.

Animals↗
PubMed1989

[Effects of size of letters on selective identification of letters].

An experiment was performed to examine the effects of the size of target and noise letters on selective identification of a target letter. Twelve undergraduate students were required to identify a target letter on a visual display which presents a target letter alone or a target letter flanked by two noise letters. The reaction time of pressing buttons to the target letter was measured under combined conditions of size of target and noise letters. The large target letter was identified faster than the small one whether it was accompanied by noise letters or not. The large noise letters exerted stronger effects on the identification of a target letter than the small one. The results agreed with the prediction based on the assertion by Eriksen and Schultz (1979). Further, it was found that the effects of size of letters varied according to the relation between target letters and noise letters and to the similarity of a target letter to noise letters.

Attention↗