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Biomedical subjects

Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 397 records · Page 22Linked to original sources
PubMed1990

An epidemiological study of the influence of sweets intake and toothbrushing on dental caries among children in Japan.

The study was designed to determine the influence of confectionery and beverages intake and of toothbrushing on infant dental caries. The participants were 700 three year old Japanese children from an urban area near Tokyo. The prevalence of caries in those who frequently consumed confectionery and beverages was higher than the prevalence in those who did not take them. However, the prevalence in children with a habit of toothbrushing did not differ from that of those without the habit. This study shows that restricting consumption of confectionery and beverages may be effective in preventing dental caries; however, encouragement of toothbrushing may not be effective in limiting dental caries progression.

Beverages↗
PubMed1990

Studies on the development of an ELISA kit for microbiological monitoring. 1. Evaluation of the reliability of the prototype kit by field tests.

The prototype of an ELISA kit using protein A as the second reaction reagent for mice and anti-rat IgG for rats was prepared for seromonitoring of the Sendai virus and mouse hepatitis virus (MHV)/sialodacryoadenitis virus (SDAV)/Parker's rat coronavirus (PCV) infections. The respective antigen strains and protein concentrations were Sendai virus MN strain, 2 micrograms/ml and MHV Nu-67 strain, 5 micrograms/ml. The reliability of this prototype kit was investigated in two field tests performed on a total of 10,094 mouse and rat sera from 147 institutions. The results indicated that the two types of kits for the two species of animals were highly specific, but it is necessary to increase the detection sensitivity of the MHV antigen for the MHV antibody of mice and SDAV/PCV antibodies of rats.

Animals↗
PubMed1990

Studies on the development of an ELISA kit for microbiological monitoring. 2. Improvement of the prototype ELISA kit with special references to mouse hepatitis virus antigen.

Improvement of the mouse hepatitis virus (MHV) antigen in a prototype ELISA kit was performed. Equivalent divalent antigens of MHV Nu-67 and S strains with a protein concentration of 10 micrograms/ml showed the best sensitivity and specificity for the detection of MHV and sialodacryoadenitis/Parker's rat coronavirus antibodies in mice and rats, respectively. An increase in the reliability of macroscopic evaluation of both antibody tests is expected by using the newly manufactured kit with the improved antigen.

Animals↗
PubMed1990

Determination of an antigen suitable for enzyme-linked immunosorbent assay of the antibody to Bordetella bronchiseptica in guinea pigs.

To establish an enzyme-linked immunosorbent assay (ELISA) technique for the serological diagnosis of infections caused by Bordetella bronchiseptica (B. bronchiseptica) in guinea pigs, the authors recently assessed the usefulness of three antigen preparations derived from the bacterial cell components: sonication antigen (S-Ag), cell surface antigen (C-Ag) and lipopolysaccharide antigen (L-Ag). The use of S-Ag for ELISA resulted in the most sensitive detection of the antibody to B. bronchiseptica from guinea pig sera immunized with killed bacteria and sera derived from naturally infected guinea pigs. Like C-Ag, S-Ag was highly specific, showing no cross-reactivity with Pasteurella multocida. Assessment of antibody formations in animals with experimentally induced infection using the three antigen preparations revealed that the antibody to S-Ag was formed earlier than antibodies to the other two antigen preparations following growth of the bacterium in the lungs. These results indicate that ELISA with S-Ag as an antigen is a useful tool for the serological diagnosis of infection by B. bronchiseptica.

Animals↗
PubMed1990

Vascular anomalies associated with aneurysms of the anterior communicating artery: microsurgical observations.

Direct operations were performed on 206 patients with aneurysms of the anterior communicating artery (ACoA) using a bifrontal craniotomy and an interhemispheric approach. A total of 44 (21.4%) of these patients had vascular anomalies in the vicinity of the ACoA; these included a median artery of the corpus callosum (MACC) in 27 cases (13.1%), duplication of the ACoA in 20 (9.7%), and duplication of the A1 segment of the anterior cerebral artery in one (0.5%). A retrospective study of the angiograms indicated that diagnosis of the A1 or ACoA duplication was not possible; only 11 (41%) of the 27 MACC's were easily identified, while eight (30%) could not be diagnosed. The majority of the cases of ACoA aneurysms with MACC (81.5%) showed trifurcation of the ACoA, A2, and MACC. The operative results in the patients with MACC did not differ significantly from the results of the entire ACoA aneurysm series. From the above study it is concluded that, regardless of whether a vascular anomaly has been identified preoperatively, ACoA aneurysm surgery should be undertaken with that possibility in mind. A bifrontal craniotomy and an interhemispheric approach has the advantage of allowing for a wide operative field and the attainment of a good understanding of the vascular structures near the ACoA. It is particularly useful in cases of vascular anomaly in this region.

Cerebral Angiography↗
PubMed1990

Characteristics of aztreonam as a substrate, inhibitor and inducer for beta-lactamases.

Aztreonam was investigated as to its characteristics as a substrate, inhibitor and inducer for the well-defined beta-lactamases of Gram-negative bacteria, and its antibacterial efficacy as to bacterial cells producing eight types of beta-lactamases was also evaluated. Aztreonam was hydrolyzed at measurable rates by class A beta-lactamases, a TEM-2 type penicillinase and the Proteus vulgaris cephalosporinase with a broad substrate range. However, the affinity of aztreonam for the class A enzymes was low, this property being well reflected by its high antibacterial activity toward producers of class A beta-lactamases. Aztreonam was extremely stable as to the typical class C cephalosporinase of Citrobacter freundii, and acted as a competitive and progressive inhibitor for the beta-lactamase. While the MICs of aztreonam in the cases of the constitutive producers of class C beta-lactamases were evidently affected by enzyme production. An experiment involving aztreonam as a inhibitor in combination with a hydrolyzable beta-lactam gave ambiguous results, however, a strong synergistic effect was found in combination with mecillinam. Using Pseudomonas aeruginosa, aztreonam was confirmed to be a poor inducer of beta-lactamases.

Amdinocillin↗
PubMed1990

[A case of recurrence of a metastatic brain tumor which disappeared due to chemotherapy only].

A rare case of recurrence of a metastatic brain tumor which disappeared due to chemotherapy only is reported. A 52-year-old male was noticed to have an abnormal shadow in his chest X-P at a routine medical examination, so a close examination was made. He was diagnosed as having right renal cell carcinoma which had metastasized to the lung. He was treated by intra-arterial infusion of anti-cancer drugs and embolization of the right renal artery. No renal symptom was seen, growth of the primary tumor stopped, and the abnormal shadow in his chest diminished. However, weakness in the left hand appeared 19 months after the first examination and he was admitted to our clinic. He was alert, but slight left hand weakness was observed. CT scan revealed a diffusely enhanced mass in the right parietal lobe. Total removal of the brain tumor was performed and the histology was metastasis of renal cell carcinoma. He was discharged and was able to walk but he had slight left hemiparesis. UFT 6 capsules a day were administrated in our out-patient clinic. However, CT scan revealed recurrence of the tumor 2 weeks after discharge, we followed up with conservative treatment, and no growth of the tumor was seen. It disappeared 5 months after discharge after being treated with UFT only. We regard UFT as having been effective in this case.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

[Influence of superior cervical ganglion on cerebral hemodynamics--measurements of cerebral blood flow and metabolism during superior cervical ganglionectomy in patients with moyamoya disease].

The effect of superior cervical ganglionectomy (SCG) on cerebral blood flow and metabolism was investigated in moyamoya disease. Measurement of cerebral blood flow and metabolism was performed in 12 cases (15 operations) of moyamoya disease during SCG. Mean age was 65.2 years (from 3 to 38). 4 were male and eight were female. Ischemic cases were 8 and hemorrhagic cases were 4. At encephalo-duro-anterio-synangiosis, a Laser Doppler flow meter and probes for measuring cortical tissue oxygen and carbon dioxide were set out to allow measurement from identical sites on the surface of the brain over the cortex. Moreover, an electromagnetic flow meter was placed on the common carotid artery. And the mean arterial blood pressure was also measured from femoral artery. After the electrode had been stabilized, continuous recordings were made of cerebral blood flow and metabolism during SCG. The mean arterial blood pressure fell slightly post operatively, but the changes in blood pressure were considered not to be significant enough to affect blood flow. Cortical CBF did not change immediately after SCG. However it increased gradually to 118.8% of preoperation level 30 minutes later respectively, and the difference was observed significant. The carotid blood flow and the tissue oxygen developed a tendency to increase after 30 minutes, but the tissue carbon dioxide did not changed. The present study indicates that superior cervical ganglionectomy is the useful procedure to increase in cerebral blood flow immediately after the operation on patients with moyamoya disease.

Adolescent↗
PubMed1990

[Encapsulated chronic intracerebral hematoma caused by venous angioma of the basal ganglia: a case report].

A case is reported of venous angioma at the right basal ganglia simulating the encapsulated chronic intracerebral hematoma. A 29-year-old man was admitted to our hospital on July 14, 1988 with a two-month history of headache. Neurological examination revealed left homonymous lower quadrantic anopsia. CT scans showed a mosaic high density lesion at the right basal ganglia with extensive adjacent edema. MRI revealed that the high density lesion on CT scans was the combination of a reticulated core of mixed signal intensity with a surrounding rim of decreased signal intensity. The lesion was accompanied with extensive edema. Followed up CT scans showed the transformation of the lesion and ring-shaped enhancement. A right frontotemporal craniotomy was performed on August 9, 1988. After thorough dissection of the sylvian fissure and small corticotomy to the insula, a tough capsule was seen. There was blood in various stages of organization in the capsule. A histological examination gave a diagnosis of venous angioma in the membrane similar to the outer membrane of chronic subdural hematomas. Postoperatively, the patient showed slight left motor weakness, but it gradually improved and he was discharged on foot, on October 19, 1988. There have been a lot of reports about angiographically occult intracranial vascular malformation (AOIVM). But AOIVM at the basal ganglia is rare, and to our knowledge, only 8 cases have been reported. In our case, the presence of adjacent extensive edema, and ring-shaped enhancement on CT scans confused the preoperative diagnosis. Those findings might have been caused by encapsulation. By using CT scans and MRI, a complete and accurate diagnosis was impossible.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Exercise-induced acute renal failure in 3 patients with renal hypouricemia.

Three cases of exercise-induced non-oliguric acute renal failure in patients with renal hypouricemia, an isolated defect of the renal urate transport system, are described. During acute renal failure, the serum uric acid levels were 5.6, 2.7 and 5.8 mg/dl, respectively, and were within normal limits. The values representing the fractional excretion of uric acid (FEUA) were 28.7, 60.0 and 12.7%, with accompanying serum creatinine levels of 8.1, 3.9 and 3.3 mg/dl, respectively. After recovery, the serum uric acid fell to 0.6, 0.7 and 1.0 mg/dl and the FEUA increased to 79.3, 52.8 and 43.2%, respectively. Two of the patients examined exhibited decreased reabsorption of filtered urate. These 3 examples of renal hypouricemia represented 23% of 13 cases of mild exercise-induced acute renal failure encountered within our experience.

Acute Kidney Injury↗
PubMed1990

[Improvement of heart failure after intracardiac operation for tetralogy of Fallot by transcatheter embolization of major aortopulmonary collateral arteries].

A two-year-and-ten-month-old female with tetralogy of Fallot with major aortopulmonary collateral arteries (MAPCAs) developed a persistent heart failure after an intracardiac repair. Angiograms revealed four MAPCAs originating from the upper portion of the descending thoracic aorta and draining into the left pulmonary artery, one MAPCA from the inferior phrenic artery into bilateral pulmonary arteries, and remaining one from the left subclavian artery into left pulmonary artery. Three of these MAPCAs were occluded by transcatheter embolization by the use of the steal coil. The heart failure was improved dramatically by this treatment.

Aorta↗
PubMed1990

[Pentatrichomonas hominis from beagle dogs--detection method, characteristics and route of infection].

Pentatrichomonas sp. from the feces of beagles was cultured axenically, and identified as P. hominis. The culture medium used was slightly modified Diamond's medium supplemented with chicken liver extract and rifampicin. Based upon good proliferation after inoculating only a few organisms in this medium, a fecal examination method employing cultivation was developed. Resistance of the trichomonad against disinfectants and metronidazole was tested, and it was found that the protozoan was rather susceptible. After oral administration of the organism to mice and rats, all the treated animals were infected. Since two types of the trichomonad, moving and non-moving, were detected, the presence of any type resistant to standing or drying was ruled out. A possible route of trichomonad infection to beagles is discussed.

Animals↗
PubMed1990

[Homocystinuria accompanied with cerebral deep venous thrombosis--a case report].

Homocystinuria is an inborn error of methionine metabolism, of which cause is mainly deficiency of cystathionine synthetase. The major clinical manifestations of homocystinuria are mental retardation, seizures, ectopia lentis, skeletal deformities and occlusive vascular disease. A case of homocystinuria accompanied with deep cerebral venous thrombosis was reported. A 29-year-old woman was admitted to our hospital with unconsciousness and tetraparesis on December 7, 1984. She was diagnosed as homocystinuria due to cystathionine synthetase deficiency at 13-year-old. Amino acid analysis of serum revealed homocystinaemia (1.37 mg/dl, normal 0), hypermethioninaemia (1.27 mg/dl, normal 0.2-0.48) and low cystathionine content. CT scan revealed intraventricular hemorrhage and diffuse low density in basal ganglia and white matter. Cerebral angiograms showed that deep cerebral veins and superior sagittal sinus can not be recognized clearly in any phase, and Sylvian veins are opacified markedly. It is suggested that intraventricular hemorrhage, and low density area in basal ganglia and white matter is due to hemorrhagic infarction by venous thrombosis of internal cerebral vein. The major clinical manifestations of homocystinuria result from the elevated plasma homocysteine level. The excitotoxic effect of homocysteic acid accounts for mental retardation and seizures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Clinical analysis of etiology of spontaneous subarachnoid hemorrhage diagnosed by computed tomography].

In 575 cases with subarachnoid hemorrhage (SAH) diagnosed by computed tomography (CT) scan, four vessel cerebral angiography was performed several times at more than two-week intervals to investigate a source of the hemorrhage. The first four-vessel study on admission revealed 530 cases (92.2%) of ruptured cerebral aneurysms, four (0.7%) of ruptured arteriovenous malformation, 25 (4.3%) of unknown etiology. Repeated four vessel study showed eight (32.0%) aneurysms among 25 cases whose first studies were negative. Six of the eight cases had aneurysms in the vertebro-basilar system. In 11 cases, repeated four-vessel study failed to detect the hemorrhagic source; and no generalized diseases were noted. One of them had recurrence of SAH 19 months after the onset of the initial one. The patient was underwent operation, which showed thrombosed ruptured aneurysm. Our present investigation demonstrated that ruptured aneurysm was responsible for 94.8% of all 575 cases of SAH detected by CT scans and 10 cases (1.7%) were diagnosed as cases of SAH of unknown etiology.

Cerebral Angiography↗
PubMed1989

Stabilization of disulfide linkage in drug-polymer-immunoglobulin conjugate by microenvironmental control.

The stability of disulfide linkage in the conjugate composed of the anti-cancer agent adriamycin, poly(ethylene glycol)-poly(aspartic acid) block copolymer, and immunoglobulin G was studied. The disulfide linkage between the block copolymer and immunoglobulin G was found to be resistant to reduction with dithiothreitol (DTT). This extraordinary resistance is considered to be brought about by steric hindrance of the poly(aspartic acid) chain binding adriamycin.

Aspartic Acid↗
PubMed1989

Evaluation of antitumor activity in a human breast tumor/nude mouse model with a special emphasis on treatment dose.

Eight lines of human breast tumors implanted in nude mice were treated with various antitumor agents at two different doses, maximum tolerated doses (MTD) and rational doses (RD) that were pharmacokinetically equivalent to the clinical doses; the response rates to both doses were compared. With MTD, the response rates to mitomycin C and vinblastine were 100%, and those to other agents including cyclophosphamide, nimustine (a water-soluble nitrosourea), vincristine, Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), 5-fluorouracil (5-FU), and methotrexate were 30%-50%, indicating high responsiveness to the former two agents. In contrast, when the RD were used, the response rates to the majority of these agents were 25%-40%, and those to vincristine and nimustine were 13% and 0%, respectively. These results agree with the reported clinical results compared with those with MTD, suggesting the importance of the use of clinically equivalent doses in the evaluation of antitumor efficacy in a human tumor/nude mouse system.

Animals↗