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Biomedical subjects

Y Masaoka

Publications and source records attributed to Y Masaoka.

33 records · Page 2Linked to original sources
PubMed1993

Use of the conjugate of disulphated ursodeoxycholic acid with p-aminobenzoic acid for the detection of intestinal bacteria.

The disulphate ester of ursodeoxycholyl-p-aminobenzoic acid (PABA-UCDA) was synthesised and compared with PABA-UDCA for its use in detection of intestinal bacteria. This compound, PABA-UDCA disulphate, had characters in common with PABA-UDCA in that it was deconjugated by cholylglycine hydrolase to release free PABA and bacteria that split glycocholic acid deconjugated PABA-UDCA disulphate. Further, in rat experiments urinary excretions of PABA were measured for six hours after oral administration of 15 mg PABA-UDCA disulphate. Ten control rats excreted (mean (SE) 188.2 (13.6) micrograms of PABA; 10 rats with an intestinal stagnant loop excreted more (530.1 (30.1) micrograms; p < 0.001): whereas 10 rats in each of three groups pretreated by oral administration of various antibiotics excreted less (polymixin B+tinidazole, 4.9 (1.6) micrograms; kanamycin, 31.0 (4.7) micrograms; clindamycin 40.9 (5.5) micrograms; p < 0.001). By contrast with PABA-UDCA, PABA-UDCA disulphate was not actively absorbed from any part of the small intestine in everted gut sac experiments, and showed poor recovery from bile after its intraileal instillation in rats. This indicated that PABA-UDCA disulphate is a single pass type substance in the gut and its oral administration test reflects the sum of the activities of bacteria in the small intestine and colon. The disulphate was easily soluble in water and this allowed its application in an in vitro test involving PABA-UDCA disulphate incubation with intraperitoneal pus (PABA-UDCA disulphate incubation test) from patients with peritonitis. This test was carried out on six patients with peritonitis, and the severity of bacterial peritonitis was expressed quantitatively. From the results obtained PABA-UDCA disulphate was considered a good material to detect intestinal bacteria.

4-Aminobenzoic Acid↗
PubMed1993

[A study on normal coronary arteriogram by provocation and spontaneous anginal attack: 4 cases of ST elevated angina with normal coronary arteries by provoked and spontaneous attacks].

During 3 years and 5 months, we experienced 3 of 172 cases of provocations on normal coronary arteries which presented ST elevated angina by ergonovine provocations. The incidence was 2.5% and 4% for all ergonovine provocations and intracoronary ergonovine provocations respectively. One case presented spontaneous attack in coronary arteriography, indicating similar state to occur not only with provocation but also in spontaneous attack. Examination of literature revealed no apparent report on such cases as this. For pathogenesis, the possibility of changes of small vessels was suggested in view of various literature and its specificity to the coronary arterial region.

Aged↗
PubMed1992

[Ocular hypotensive effect of alpha-adrenoceptor agonist and antagonist in the conscious pigmented rabbit].

It has been reported that some of the topically-used antiglaucomatics have a central ocular hypotensive effect. In this study, the influence of topical and intracerebroventricular (i.c.v.) administration of phenylephrine, clonidine, guanfacine, prazosin, yohimbine on the intraocular pressure (IOP) was investigated in the rabbit. Male pigmented rabbits were used throughout the experiments. For measurement of IOP, an applanation pneumatonograph was used. By unilateral topical administration of phenylephrine, an increase in IOP in the eye in which instillation was performed was observed. On the other hand, a slight decrease in IOP was observed by similar treatment of prazosin and yohimbine. No significant change of IOP in the contralateral eye was observed with these drugs. On the contrary, unilateral topical administration of clonidine or guanfacine decreased the IOP of both eyes. Furthermore, the decrease of IOP was more remarkable in the contralateral eye compared to the eye which received instillation. The IOP of both eyes was decreased in a dose-related fashion by i.c.v. administration of clonidine or guanfacine. The ocular hypotensive effects of clonidine were diminished by the pretreatment by i.c.v. administration with yohimbine. These results suggest that the ocular hypotensive effect of clonidine and guanfacine is due to their alpha 2-adrenoceptor stimulation in the central nervous system.

Administration, Topical↗
PubMed1991

Basic studies on ursodeoxycholyl-para-aminobenzoic acid for evaluation of intestinal microflora.

A newly synthesized conjugate of ursodeoxycholic acid with para-aminobenzoic acid (PABA) was investigated to determine its suitability for evaluation of enteric bacteria. This compound, PABA-UDCA, was deconjugated by cholylglycine hydrolase to release free PABA, whereas it was completely resistant to deconjugation by pancreatic and intestinal mucosal enzymes. In bacteriologic experiments almost all the microorganisms that split glycocholic acid deconjugated PABA-UDCA. In rat experiments urinary excretions of PABA were measured during 6 h after oral administration of 10 mg PABA-UDCA (PABA-UDCA administration test). Ten control rats excreted 338.5 +/- 13.8 micrograms (mean +/- SE) of PABA; 10 rats with intestinal stagnant loop excreted more (673.6 +/- 70.2 micrograms; P less than 0.01); whereas 10 rats in each of 7 groups pretreated with oral administration of various antibiotics excreted less (P less than 0.001; polymixin B + tinidazole, 14.0 +/- 2.5 micrograms; polymixin B, 224.9 +/- 23.5 micrograms; tinidazole, 42.7 +/- 8.6 micrograms; kanamycin, 50.3 +/- 5.8 micrograms; clindamycin, 57.4 +/- 7.4 micrograms; vancomycin, 70.4 +/- 8.5 micrograms; and paromomycin, 160.4 +/- 16.4 micrograms). This result was reflected by the bacterial mean count of feces. In the PABA-UDCA administration test, after 2 months of feeding with different diets, rats with high-fiber diet (n = 10) excreted less PABA in urine (70.9 +/- 15.9 micrograms; P less than 0.001) than rats on a control diet (n = 10) and a high-protein-high-fat diet (n = 10) (288.9 +/- 34.5 micrograms and 386.7 +/- 61.2 micrograms, respectively). Fecal bacteriologic status was consistently altered. In human volunteers 250 mg PABA-UDCA was tested. Amounts of PABA excreted in urine during 6 h after dosing were 21.11 +/- 2.02 mg in controls (n = 5) and 12.20 +/- 1.01 mg in the group treated with polymixin B plus tinidazole (n = 5; P less than 0.01). No adverse effect was observed. These basic studies indicate that this compound is likely to offer a simple and rapid method for evaluation of the intestinal microorganisms without use of radioisotopes or expensive, special equipment.

4-Aminobenzoic Acid↗
PubMed1985

[Transient appearance of asynergy on the echocardiogram and electrocardiographic changes simulating acute myocardial infarction following non-cardiac surgery].

Two-dimensional echocardiography (2-D echo) was performed for six postoperative patients who had acute myocardial infarction (AMI)-like electrocardiographic (ECG) changes. All but one, who had coronary T waves, demonstrated abnormal Q waves in V1-V4, decreased amplitude of R waves, and low voltage in limb leads. ST elevation was also observed. Abnormal Q waves in V1-V4 began to resolve in a few days and the QRS complex reverted to normal within one month; however, coronary T waves were observed for at least three months. In the remainder one, persistent Q waves were present from the onset. 2-D echo, performed simultaneously with ECG, showed akinesis or dyskinesis accompanied by ventricular dilatation, not only at the anterior septum, anterior wall and around the apex, but in more extensive areas in four of five cases with abnormal Q waves in V1-V4. In two other cases, which showed abnormal Q or coronary T waves alone, akinesis was limited to the anterior septum and to the septal site and anterior wall of the apex. All abnormal findings on 2-D echo completely resolved within one month, as the ECG findings returned to normal. Compared with typical AMI showing abnormal Q waves in V1-V4, asynergy was recognized in more extensive areas and abnormal wall motion indices significantly improved in the postoperative cases. In the postoperative cases with AMI-like ECG, the CPK-MB fraction increased; however, the peak level of CPK was lower than that in typical AMI. On the basis of these results, transient AMI-like ECG findings in postoperative cases are due to extensive myocardial damage, which is probably derived from focal myocytolysis.

Aged↗
PubMedDate not supplied

The early phase of colon tumorigenesis induced by dimethylhydrazine in ICR mice.

In order to study the influence of fiber supplements on dimethylhydrazine induction of colon tumorigenesis six-week-old CD1 (ICR): Crj mice were injected i.m. at a dimethylhydrazine (DMH) dose 10 mg/kg body weight once weekly for 10 weeks with or without dietary supplementation with 3% polydextrose, lactosucrose or cellulose, or 3% polydextrose and 3% cellulose in combination. There were no significant differences in colon tumor induction among the groups. However, microadenomas were observed 10 weeks after the first treatment of DMH so that this protocol may be useful for studies of the early phase of colon carcinogenesis in mice.

Adenocarcinoma↗
PubMedDate not supplied

Effects of azoxymethane on X-ray induced intestinal metaplasia in Donryu rats.

The present study was undertaken to determine the effect of azoxymethane (AOM) administration on intestinal metaplasia induced by X-irradiation in male Donryu rats. Five-week-old animals were X-irradiated with two doses of 10 Gy each at a 3-day interval or three X-ray doses of 10 Gy at a 2-day interval and then received AOM injections i.m. at a dose of 15 mg/kg body weight once weekly for 3 weeks, 6 months after irradiation. Alkaline phosphatase positive foci were decreased after AOM treatments, but aberrant crypt like-foci appeared within areas of intestinal metaplasia. In contrast no induction was observed in normal-appearing gastric mucosa.

Alkaline Phosphatase↗
PubMedDate not supplied

Tumorigenesis in F1 offspring mice following paternal 12.5 cGy 252Cf fission neutron irradiation.

Experiments were conducted to determine whether following genetic damage at germ cell stages induced by paternal exposure to 252Cf fission neutron could lead to tumorigenesis in the offspring. Seven-week-old C3H/HeNCrj male mice were irradiated with 252Cf fission neutrons, at doses of 0 and 12.5 cGy and were mated with nine-week-old C57BL/6NCrj females two weeks after the exposure. Three weeks later, it was found that the proportion of abnormal sperm in the 12.5 cGy-irradiated males was higher than that of 0 cGy-irradiated group. Embryo lethality among the F1 offspring was also found to be higher in the 12.5 cGy group than in the 0 cGy group, while the incidence of liver tumors among the F1 offspring increased in males only. These results suggest that the paternal 12. 5 cGy radiation exposure may have caused genetic transmission of liver tumor-associated traits, which is in line with findings that show steep increase in incidence of tumorigenesis in B6C3F1.

Animals↗