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Biomedical subjects

S Nitta

Publications and source records attributed to S Nitta.

At least 199 records · Page 11Linked to original sources
PubMed1983

Metabolism of afloqualone, a new centrally acting muscle relaxant, in monkeys and dogs.

The disposition and metabolism of afloqualone [6-amino-2-fluoromethyl-3-(o-tolyl)-4(3H)-quinazolinone, AFQ] were studied in monkeys and dogs after oral administration of 14C-AFQ. In both species the blood radioactivity reached a maximum 1 to 2 h after the administration, and decreased with apparent half-lives of 3.2 h in the monkey and 7.2 h in the dog. A total of about 90% of the administered radioactivity was recovered from the urine (monkey, 72.3%; dog, 51.8%) and feces (monkey, 19.4%; dog, 36.7%) within 4 or 5 d. AFQ was extensively metabolized in both species. There were species differences in the composition of the urinary metabolites. In the dog, AFQ was monohydroxylated at the 2-, 2'-, 3'- and principally 4'-position and each metabolite was further conjugated with glucuronic acid. N-Acetylated metabolites were not detected. In the monkey, N-acetylation was the main initial step of metabolism followed by hydroxylation at the acetyl-methyl, 2'-methyl and 2-fluoromethyl groups. Phenolic metabolites such as 3'- and 4'-hydroxylated AFQ were not detected. Both animals excreted sulfur-containing metabolites such as the 2-methylthio, 2-methylsulfinyl and 2-methylsulfonyl derivatives of AFQ.

Animals↗
PubMed1982

Reconstruction of the right ventricle with diaphragm driven right ventricular wall device.

For the treatment of congenital cardiac anomalies associated with hypoplastic right ventricle such as tricuspid atresia, various methods have been used in clinical and experimental studies. Though these methods were effective, there remained still some problems such as postoperative right heart failure or restriction of indications for the cases associated with high pulmonary vascular resistance. In order to solve these problems, diaphragm driven right ventricular wall device (RVWD) was newly developed. The device is composed of hard outer housing and soft diaphragm made of polyurethane and actuated pneumatically triggered to R wave of ECG or left ventricular pressure. Characteristics of RVWD were checked using a mock circulation to find optimal driving condition for animal experiments. Acute experiments were carried out using 15 mongrel dogs. Right ventricular free wall was excised as wide as possible under hypothermic inflow occlusion and RVWD was sutured to the edges of right ventriculotomy. Hemodynamics were investigated with and without driving of RVWD for 6 to 24 hr. RVWD was able to maintain hemodynamics efficiently during immediate postoperative period. After body temperature and cardiac function returned to normal, systemic circulation could be maintained without driving of RVWD. From the results of this study, possibly of surgical correction of hypoplastic right ventricle using RVWD was presumed.

Animals↗
PubMed1982

Quantitative assessment of water content of human lung: a study on open lung biopsy specimen.

Quantitative assessments of human lung water are necessary to evaluate lung water changes, but little knowledge is available about a human "normal" lung. To determine a "normal" lung water content, pieces of lung tissue were obtained from lungs which should be resected for solitary nodular lung diseases, and the water content was assessed in terms of the ratio of extravascular lung water to blood free dry lung weight (Qw1), using the gravimetric methods. Among 152 patients who underwent open thorax surgeries for their solitary nodular lung diseases, 35 lung specimens were obtained from lungs which were free from any abnormal lesions. Since the postoperative histological examination did not reveal any pathological findings except for the solitary nodules in the resected lobes of 35 patients, the 35 pieces were also considered to be "normal". The value of Qw1 was 3.66 +/- 0.29 (mean +/- S.D.) g/g blood free dry lung. This value would serve as a reference of Qw1 in human "normal" lung.

Adult↗
PubMed1982

Effects of irradiation on the pulmonary vascular fluid and protein exchange.

In anesthetized sheep, ventilated by positive pressure, pulmonary arterial and left atrial pressures, cardiac output, and lung lymph flow (Qlym) were measured and lymph-to-plasma protein concentration ratio (L/P) was determined. For sheep were irradiated with 60Co on the bilateral lower lobes, avoiding irradiation on the heart and the caudal mediastinal lymph node. Qlym increased during and after irradiation, and reached a new steady state (160% increase), while pulmonary arterial or left atrial pressure did not change. In 4 control experiments, pulmonary hemodynamics, Qlym or L/P did not change. Therefore the increased fluid or protein flux after irradiation cannot be ascribed only to abnormal pulmonary hemodynamics. Endothelial damages seem to play a role in the increase of fluid filtration and protein permeability.

Animals↗
PubMed1982

[Transthoracic catheterization under monitoring by ultrasono-cardiotomography and its clinical usefulness].

When serious postoperative complications such as mechanical malfunction of the implanted valve occur in patients with multiple valvular replacements, it is very urgent to evaluate the function of the valve and heart and to establish an accurate diagnosis as to the damaged prosthetic valve, while giving intensive life-saving bed-side care. Under such circumstances, transvascular heart catheterization necessary for obtaining hemodynamic data or for angiocardiography can not be applied because it is almost impossible for a catheter to pass through a prosthetic valve without potential danger. Then, the present authors have introduced a method of cardiac catheterization by a direct transthoracic route during which cardiac structures are monitored by ultrasono-cardiotomography. This method is called "transthoracic catheterization monitored by ultrasono-cardiotomography," and was applied to cases of double (aortic and mitral) valve replacements. The immobile adhesive area in the vicinity the right ventricular wall is detected from the longitudinal or horizontal cross-section pictures, through which a polyethylene catheter with stylet was introduced from the subxiphoid region and was advanced toward the left ventricle. After introduction of the catheter into the right ventricle, the catheter tip was advanced to the midportion of the ventricular septum, which was selected to avoid the penetration of the tricuspid valve and coronary arteries. Then, the catheter was passed into the left ventricle on the ultrasonic scanning plane along the direction of the short axis of the heart. After placing the catheter into the left ventricle, a small amount of contrast material was injected to confirm the precise positioning of the catheter tip in the left ventricle. Thus, the hemodynamic measurement and angiocardiograpy were performed easily. By utilizing contrast cardiotomography, valvular function was evaluated easily without any side effects as in case of angiocardiography. Furthermore, ultrasono-cardiotomography was sensitive in detecting cardiac tamponade if appeared during direct heart catheterization, making immediate treatment possible. Thus, transthoracic catheterization monitored by ultrasono-cardiotomography was useful for the evaluation of the function of the prosthetic valve, especially in cases with double valve prostheses.

Adult↗
PubMed1981

[Canine parvovirus infection in a group of beagles (author's transl)].

An outbreak of canine parvovirus infection in a group of 26 beagles was described. The disease characterized by acute intestinal involvement was highly contagious but fatality was low (1/26). Transient leukopenia was recorded in some animals. All the convalescent sera were positive in agar gel diffusion test using feline panleukopenia virus antigen. Histopathological examination on fetal dog revealed regressive change associated with formation of amphophilic intranuclear inclusion bodies in the enterocytes of the Lieberkühn's crypt and regressive change in the lymphoid tissues. Pathologic picture exhibited strikingly resemblance with that of feline panleukopenia.

Animals↗