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Biomedical subjects

T Tsuchiya

Publications and source records attributed to T Tsuchiya.

At least 559 records · Page 31Linked to original sources
PubMed1989

[Observation on calcification of necrotic tissue in pressure side of periodontal membrane incident to experimental tooth movement].

In an orthodontic point of view, it is said that necrotic tissues cause a standstill of tooth movement until they disappear and that term of the standstill is related to the size of the necrotic tissues. Although remodeling processes of a periodontal membrane in compressed area were reported as series of phenomena like degeneration, coagulative necrosis, calcification and histiolysis, there is no direct evidence that the necrotic tissue is really calcified. The purpose of this study is to clarify histologically whether the necrotic tissues in the periodontal membrane are calcified or not and to know when appearance and disappearance of the calcification occur during an experimental tooth movement. Twenty eight rats were used for this study. For the experimental tooth movement, the orthodontic elastics were inserted into the interproximal space between the maxillary right 1st and 2nd molars during 1, 2, 3, 5, 7 and 14 days respectively (Waldo's method). The periodontal tissues were observed on undecalcified sections by vital staining in which oxytetracycline (3 mg/kg), alizarin red (8 mg/kg) and calcein (0.8 mg/kg) were applied as well as by contact micro radiography (CMR). Findings were as follows: 1) After 2 days of tooth movement, a part of the periodontal membrane in compressed area showed fluorescence by vital staining and was radiopaque by CMR. This means that the necrotic tissues are really calcified at least after 2 days of experimental tooth movement. 2) After 7-14 days no calcified tissue could be found in the periodontal membrane. The calcified tissues may disappear under processes of resorption in this area.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Study on supernumerary teeth in the maxillary anterior area in children. 1. Clinical analysis.

This is a study of supernumerary teeth in the maxillary anterior area in children. More than 60,000 child patients were examined. The 842 supernumerary teeth in the maxillary anterior area, found in a total of 682 children, were analyzed clinically. The incidence of supernumerary teeth was 1.12%. The male-female ratio was 3 to 1. Supernumerary teeth found were single and multiple types, with a ratio of 3 to 1. The eruption direction was normal (51.2%), inverted (36.2%) or horizontal (7.6%). Approximately 65% were found impacted in the maxilla.

Adolescent↗
PubMed1989

Electron microscopic studies on the stretch-induced disordering of the myofilament lattice in tetanized frog skeletal muscle fibers.

To study the effect of stretch on the hexagonal myofilament lattice in frog skeletal muscle fibers, the fibers were fixed at rest and during the isometric tetanus with or without stretch, and their cross sections were examined electron microscopically. The degree of disorder of the myofilament lattice as estimated by the Fourier transform and rotation methods in the digital image analysis was found to be largest during the isometeric tetanus with stretch and smallest during the isometeric tetanus without stretch, supporting the view that the stretch-induced force enhancement results from the disordering of the myofilament lattice.

Actin Cytoskeleton↗
PubMed1989

Arterial-venous plasma concentration differences of 6-chloro-2-pyridylmethyl nitrate in humans after sublingual administration.

The plasma concentrations of 6-chloro-2-pyridylmethyl nitrate after sublingual administration were determined in six healthy male volunteers (venous plasma) and eleven patients (arterial plasma) with ischemic heart failure. The pharmacokinetics of the compound was investigated in volunteers. Plasma concentration-time data in each volunteer were found to fit a two-compartment open model with zero-order absorption. The pharmacokinetic parameters estimated from curve-fitting the plasma concentration-time data were as follow: Tmax 10 +/- 2.8 min, Cmax 8.16 +/- 2.48 ng/mL and CLP 6.16 +/- 1.79 L/min (means +/- S.D.). The arterial plasma concentrations (11.9 +/- 5.14 ng/mL) 7 min after sublingual administration were significantly higher (p less than 0.05) than those in venous samples (6.86 +/- 2.80 ng/mL). These results support that the arterial-venous gradient exists after administration of 6-chloro-2-pyridylmethyl nitrate in humans.

Administration, Sublingual↗
PubMed1989

[A study of left ventricular rupture associated with acute myocardial infarction].

A report is presented on 9 cases of left ventricular rupture associated with acute myocardial infarction experienced at Tsuchiya Hospital from January 1983 to August 1987. These cases accounted for 2.6% of the 384 cases of acute myocardial infarction admitted during the same period. Cases of cardiac rupture were classified according to clinical symptoms and hemodynamic findings obtained into three types, blow out type, subacute type, and our newly added intermediate type. In the intermediate type, there is depression of blood pressure to the level of losing consciousness but improvement of blood pressure and consciousness through medical treatment and time is available to permit surgical treatment in comparison with the blow out type. The therapeutic results were studied by the types. Among the four cases of blow out type, closure of the ventricular rupture was made under the extracorporeal circulation in one case, release of tamponade only under thoracotomy in the CCU in one case, and medical treatment only in two case, but none of the cases survived. Surgical closure of the ventricular rupture was made in all the three cases of the subacute type and all the cases are surviving. Of the two cases of the intermediate type who underwent surgical closure of the ventricular rupture, only one case could be salvaged. In examining the risk factors of cardiac rupture, a high rate of cardiac rupture was observed in initial cases of myocardial infarction without a past history of angina attack and in cases of coronary occlusion without evidence of peripheral collateral flow by emergency coronary angiography.

Aged↗
PubMed1989

[Anesthesia in patients undergoing valvular replacement and coronary artery bypass grafting].

We investigated the intraoperative hemodynamic changes in patients who underwent combined valvular replacement (VR) and coronary artery bypass grafting (CABG). The data of 8 patients who under went VR + CABG were compared with those of 50 patients who underwent VR during the same period (1986). Heart rate before the institution of cardiopulmonary bypass (CPB) was not different between these two group, but blood pressure of VR + CABG cases was significantly higher than that of VR cases. This required a higher dosage of fentanyl in VR + CABG cases.

Aged↗
PubMed1989

[Intraoperative management of emergency coronary artery bypass grafting].

Intraoperative hemodynamics during emergency coronary artery bypass grafting (CABG) for acute evolving myocardial infarction (26 cases) were measured and compared with those during elective CABG (39 cases). Before cardiopulmonary bypass period, it was strongly suggested that the cardiac function of emergency cases was worse than that of elective cases because of the following 5 factors; (1) hypotension, (2) tachycardia, (3) low stroke volume index, (4) pulmonary congestion and (5) metabolic acidosis. Proper usage of inotropic supports, vasodilators, anesthetic agents, and control of acidosis and hypoxemia seemed to be more important in emergency CABG. These prudent intraoperative hemodynamic managements have played important roles in the progress of the operative outcome of emergency CABG.

Adult↗
PubMed1989

[Anesthesia for patients receiving hemodialysis--a report of 122 cases].

A hundred and twenty-two cases of anesthesia for patients receiving hemo-dialysis were reported and peri-operative management of them was analyzed, retrospectively. For the past ten years, most of the patients were anesthetized with neurolept-anesthesia and post-operative mechanical ventilation was continued until the patients regained stable hemodynamics and complete awareness. The procedures of pre-operative hemo-dialysis and intraoperative management were almost compatible with previous reports. In the cases of emergency operation, pre-operative control was not enough and intra-operative water intake was larger than that of scheduled cases. The detailed analysis of peri-operative management of water which affects the pathophysiological state of each patient will be the problem in future.

Adolescent↗
PubMed1988

[Estimation of absorbed dose of beta radiation into the critical tissues by a single injection of tritiated water].

The biological effects of tritium in humans need to be clarified, because the chances of humans becoming exposed to tritium beta radiation may increase with the development of the nuclear fusion reactor. To evaluate the biological effects of tritium, it is necessary to estimate exactly the absorbed dose from the tritium beta rays in the tissue. In many reports, the absorbed dose of HTO in the tissues is estimated from the tritium content in body fluid and dose calculations are customarily based upon the water content of soft tissues, which is taken to be 0.7 to 0.8. However, these methods may not show the exact absorbed dose in the organs. In the present study, the radioactivity of the critical tissues was measured directly using a sample oxidizer and the absorbed dose was calculated from the radioactivity of tritium in the tissues. Details on the method for calculation of the absorbed dose in tissues of the mouse is shown in this report. The results suggest that the absorbed dose should be obtained from the radioactivity in the tissues.

Absorption↗
PubMed1988

A novel enhancement of SV40 enhancer activity by treatment of mouse neuroblastoma N18TG2 with protein kinase inhibitor H-7.

To determine the role of protein phosphorylation in transcription regulation, we have treated mouse neuroblastoma N18TG2 cells with the protein kinase inhibitor H-7 and tested its effect on transcription. After the preculture and transfection in the presence of H-7, the cell preparation was divided in half and cultured with and without H-7. The level of CAT expression of pSV2-CAT was found to be higher in the cells cultured in the absence of H-7 than in those cultured in the presence of H-7. This difference was observed only after pretreatment of the cells with H-7, suggesting that withdrawal of H-7 from the culture medium after preculture with H-7 gave an enhancing effect on CAT expression. This phenomenon was also observed with transformants that expressed the CAT gene of pSV2-CAT stably. The 72 base-pair (bp) repeat of SV40 DNA was responsible for this difference in CAT expression. A similar effect of H-7 on the SV40 enhancer activity was observed in mouse neuroblastoma x rat glioma hybrid NG108-15 cells, but not in rat glioma C6-BU-1 cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Amino acid substitutions and alteration in cation specificity in the melibiose carrier of Escherichia coli.

We isolated mutants of Escherichia coli which showed Li+-resistant growth on melibiose. The melibiose carrier of the mutants lost the ability to couple to H+, whereas it retained the ability to couple to Na+. The mutated gene, melB, of the mutants was cloned, and the nucleotide sequence was determined. The nucleotide replacements caused the following substitutions of amino acid residues in the melibiose carrier: Pro-142 with Ser, Leu-232 with Phe, or Ala-236 with Thr or Val. These amino acid residues are located in slightly hydrophobic regions of the melibiose carrier. The results provide strong support for the idea that such regions or their vicinities which contain those amino acid residues play an important role in H+ (or Li+) recognition or H+ (or Li+) transport by the melibiose carrier.

Base Sequence↗
PubMed1988

Entrainment of idiopathic ventricular tachycardia of left ventricular origin with evidence for reentry with an area of slow conduction and effect of verapamil.

Recurrent sustained ventricular tachycardia (VT) with QRS morphology of the right bundle branch block and left axis deviation was studied in 4 patients without any underlying heart diseases. The mean VT rate was 155 beats/min and the endocardial catheter mapping during VT showed the earliest activation site at the left ventricular lateral wall near the apex. In all patients, rapid pacing from the right ventricular outflow tract during VT resulted in constant fusion beats except for the last entrained beat (thus VT was entrained), while pacing from the right ventricular apex and from the earliest activation site failed to demonstrate entrainment. During entrainment from the right ventricular outflow tract (mean pacing rate 168 beats/min), conduction intervals from the pacing site to the earliest activation site (St-A interval) and to the right ventricular apex (St-B interval) were measured in 3 patients. The St-A intervals were 400, 410 and 440 ms and the St-B intervals were 80, 70 and 90 ms, respectively. A small dose of verapamil (1.0 mg) was administered during VT, which resulted in a decrease of VT rate by a mean of 23 beats/min. During entrainment from the right ventricular outflow tract the St-A interval was prolonged in all 3 patients while the St-B interval remained the same. In conclusion, the mechanism of this VT was best explained by reentry with an area of slow conduction. Verapamil slowed the rate of VT by prolonging conduction within the area of slow conduction. Tachycardia entrainment makes possible a selective examination of antiarrhythmic drug effect on the area of slow conduction within the reentry circuit of VT.

Adolescent↗