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Biomedical subjects

A Shinohara

Publications and source records attributed to A Shinohara.

At least 109 records · Page 6Linked to original sources
PubMed1992

Rad51 protein involved in repair and recombination in S. cerevisiae is a RecA-like protein.

The RAD51 gene of S. cerevisiae is involved in mitotic recombination and repair of DNA damage and also in meiosis. We show that the rad51 null mutant accumulates meiosis-specific double-strand breaks (DSBs) at a recombination hotspot and reduces the formation of physical recombinants. Rad51 protein shows structural similarity to RecA protein, the bacterial strand exchange protein. Furthermore, we have found that Rad51 protein is similar to RecA in its DNA binding properties and binds directly to Rad52 protein, which also plays a crucial role in recombination. These results suggest that the Rad51 protein, probably together with Rad52 protein, is involved in a step to convert DSBs to the next intermediate in recombination. Rad51 protein is also homologous to a meiosis-specific Dmc1 protein of S. cerevisiae.

Amino Acid Sequence↗
PubMed1992

Sex-linked recessive lethal test of Drosophila melanogaster after exposure to 50-Hz magnetic fields.

To determine whether a 50-Hz magnetic field will induce mutations, a sex-linked recessive lethal test of Drosophila melanogaster was performed. Adult flies were exposed at an rms flux density of 500 mu T or 5 mT to the homogeneous field of a Helmholtz coil. The ambient field to which controls were exposed was less than 1 mu T. Exposures took place continuously for 13 to 14 days, which correspond to the life cycle of Drosophila at 25 degrees C. About 10,000 X-chromosomes were tested at each flux density. Recessive lethal mutation rates of 0.13, 0.21, and 0.18 percent were observed, respectively, for control, 500-mu T, and 5-mT conditions. By the Kastenbaum-Bowman significance test, the recessive lethal mutation rates in the 500-mu T and 5-mT conditions did not differ from the mutation rate of controls.

Animals↗
PubMed1992

Inhibition of erythrocyte 5-aminolaevulinate hydrolase activity by tin and its prevention by selenite.

Mice were injected with either SnCl2 (intraperitoneal) or Na2SeO3 (subcutaneous) alone or together at doses of 50 mumol/kg body weight. After 20 hours blood was collected and the concentrations of tin (Sn) and Selenium (Se) and the activity of 5-aminolaevulinate hydrolyase (ALA dehydratase, EC 4.2.1.24) in blood were determined. The concentrations of Sn in whole blood were 4.9 (SD 1.5) nmol/ml (n = 4) and ALA dehydratase activity was 10% of the control in Sn treated animals. Concentrations of Sn were 2.6 (SD 0.6) nmol/ml and ALA dehydratase activity was 92% of that in control animals when Sn and Se were simultaneously injected. The supernatant from lysed erythrocytes from Sn treated mice were applied to a Sephacryl S-300 column. The predominant peak containing Sn was eluted at the position of haemoglobin; a second peak was eluted at the position of ALA dehydratase. When the supernatant of lysed erythrocytes from mice injected with Sn and Se was chromatographed, a negligible amount of Sn was detected in the ALA dehydratase fraction. It thus appears that Sn binds to ALA dehydratase molecules and inhibits enzyme activity, and that simultaneous injection of Se prevents Sn binding to ALA dehydratase, thereby preventing the inhibition of ALA dehydratase activity by Sn.

Animals↗
PubMed1992

[Determination of protoporphyrins in blood using HPLC. Standardization of protoporphyrins and interlaboratory comparison of analyses].

1) In order to compare the results of determination of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZP) using HPLC, the preparation procedures for standard solutions of PP and ZP were studied at four laboratories. According to the methods mutually agreeable to the four laboratories, the absorption values using UV-Vis spectrometer from the 4 laboratories were found to be identical. 2) The total of 28 whole blood samples obtained from the same workers whose Pb-B levels ranged from 2.9 to 87.9 micrograms/dl were sent to the 4 laboratories for determination of PP and ZP. The laboratories were allowed to use their own HPLC apparatus, column, mobile phase and fluorometric detectors, although the same procedures were used to prepare the standard solutions of PP and ZP. The results showed that significant biases in ZP and PP levels were found between two out of the 4 laboratories, but the ZP values corrected by the recovery rate showed no statistical difference among the laboratories. 3) Blood levels of ZP, total protoporphyrin (TP, calculated by PP+ZP/1.1), and PP determined by HPLC method correlated well with free erythrocyte protoporphyrin (FEP) determined by the method of extraction into the acidic solvent. The correlation coefficients between Pb-B and log TP, ZP, FEP or PP were 0.82-0.84, 0.80-0.83, 0.786, or 0.70-0.73, respectively. 4) The coincident ratios of PP/TP obtained at 4 laboratories ranged from 12.1 to 19.0%. These values were within a relatively narrow range, although two different kinds of organic solvents (DMF: N',N'-dimethylformamide or Methanol/triton-X 100) were used in the extraction steps.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1992

Two sudden death cases of idiopathic ventricular tachycardia.

It is said that the prognosis of idiopathic ventricular tachycardia (IVT) without organic heart disease is good in general. In this paper, two sudden death cases of IVT are reported. The first case was a 44-year-old male, who was referred to our hospital for further examination and treatment of ventricular tachycardia. Echocardiography did not show obvious organic heart disease. After the patient was diagnosed with IVT, he was given drug therapy at the outpatient clinic. However, about six months later, he died suddenly while playing mahjong late at night. The second case was a 17-year-old male. He was also referred to our hospital by another hospital after being diagnosed with ventricular tachycardia. A diagnosis of IVT was made, for which he was given drug therapy at outpatient clinic. However, the patient discontinued receiving the drug therapy. The patient died suddenly about 3 months after discontinuation of the therapy. Some idiopathic ventricular tachycardia cases have poor prognosis like the present ones. It was considered necessary to thoroughly control and guide patients with their daily life and monitor them carefully about the ingestion of anti-arrhythmic agents.

Adolescent↗
PubMed1992

A case of concealed WPW syndrome with three different reciprocal tachycardias due to triple AV nodal pathways.

Triple atrioventricular nodal pathways (TAVNP) occur occasionally, but it is rare for them to produce more than two different tachycardias. Here we report a case of concealed WPW syndrome with three different tachycardias. During electrophysiologic studies, three different reciprocal tachycardias were induced. Tachycardia #1 was characterized by a cycle length of 230 msec and an A'-H interval of 70 msec. For tachycardia #2, these parameters were 300 msec and 140 msec, while they were 370 msec and 200 msec for tachycardia #3. During all three tachycardias, the earliest atrial activity was observed in the left atrium. Ventriculoatrial conduction occurred following ventricular stimulation, and the earliest atrial activity was observed in the left atrium, indicating the existence of left-sided accessory pathway. Persistence of tachycardia for 15-30 min caused marked pulmonary congestion. The heart rate was very high (260 beats/min) during tachycardia #1, and the pulmonary arterial pressure rose to 40/30 mmHg, with the pulmonary arterial diastolic pressure remaining at about 30 mmHg throughout the tachycardia. It seems that the pulmonary venous pressure rises abnormally during paroxysmal supraventricular tachycardia with a very high heart rate and that pulmonary congestion can easily occur during a short period of tachycardia.

Electrocardiography↗
PubMed1992

[A case with hepatocellular carcinoma effectively treated by continuous hepatic arterial infusion of etoposide, epirubicin and CDDP].

A 53-year-old man who suffered from advanced hepatocellular carcinoma (HCC) was treated with hepatic arterial infusion (HAI) of Etoposide, Epirubicin and CDDP. Treatment consisted of a continuous HAI of Epirubicin (50 mg/body, day 1.7), CDDP (75 mg/body, day 2.8) and Etoposide (80 mg/body, day 4-6). He had two series of infusions and was treated by transarterial embolization using CDDP powder (100 mg) added to lipiodol and aluminum stearate as suspension following HAI. The tumor regression rate was about 60% after HAI, but the remaining tumor seemed to be almost necrotic. AFP and PIVKA-II reached the normal range after TAE. We could not find lipiodol accumulated in tumor on CT carried out eight weeks after TAE. No recurrence has been noticed in the following 8 months. Toxicity was not so severe and was well tolerated.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Distribution of terbium and increase in calcium concentrations in organs of mice administered with terbium chloride.

To investigate the biological effects of terbium (Tb), male mice were intraperitoneally administered with TbCl3 at doses of 10, 50, or 250 mg Tb/kg. The Tb distribution in organs was determined after 18-20 h of injection by using a spectrofluorometer. The concentrations of Ca, Mg, Fe, and Zn in various organs were determined by atomic absorption spectrometer. Tb administered was mainly found in pancreas, seminal vesicles, spleen, liver, and testes. In each organ. Tb concentration increased according to the dosage of Tb. Contrary to our expectation, the increase of Ca concentration was obvious in organs in which high Tb concentrations were found. The correlation coefficients between Tb and Ca concentrations were from 0.863 in spleen to 0.986 in liver. In heart, lung, and blood. Tb was scarcely detected and insignificant change of Ca concentrations was observed. This result suggests that Tb induces increased Ca concentrations in organs.

Animals↗
PubMed1991

[A case of metastatic rib tumor from thyroid cancer confirmed by the presence of thyroglobulin].

A 63-year-old female, with a chief complaint of right chest pain was referred to our hospital because of an abnormal right chest wall shadow on chest X-ray. A rib tumor was suspected based on her chest CT scan. Percutaneous needle biopsy yielded a diagnosis of well-differentiated adenocarcinoma. As metastatic rib tumor was suspected, the primary tumor was sought for. A thyroid gland nodule was recognized by ultrasonography, and the cytological diagnosis was class V. Immunohistological demonstration of the thyroglobulin studies of the rib tumor tissue revealed papillary and trabecular patterns of cell arrangement and the presence of thyroglobulin existence. Definitive diagnosis of metastatic rib tumor from thyroid cancer was established. Immunohistological examination is useful to confirm the diagnosis of metastatic cancer of thyroid origin.

Adenocarcinoma↗
PubMed1991

Right atrial myxoma with hypervascularity demonstrated by selective coronary angiography.

Cardiac myxoma is the commonest primary cardiac tumor, however, the incidence of right atrial myxoma is very rare. We reported a 71-year-old man with a right atrial myxoma, whose main complaint was fever of unknown origin. Definite diagnosis was confirmed by echocardiography and cineangiocardiography. Venacavogram revealed huge mass which occupied greater part of right atrial cavity. Coronary angiogram revealed the feeding artery arising from left coronary circumflex artery and the sign of hypervascularity. Open heart surgery was performed, and a 4.9 x 4.0 x 3.8 cm tumor was found in the right atrial cavity. Pathological examination showed the findings of myxoma. Postoperative clinical course was uneventful.

Aged↗
PubMed1991

The efficacy of isoproterenol on quinidine induced torsade de pointes.

The efficacy of isoproterenol for torsade de pointes (TdP) was evaluated in 60 dogs. TdP was induced in 34 of 60 dogs (56.7%) after the administration of quinidine sulfate (30 mg/kg). The electrophysiologic effect of isoproterenol (0.5 micrograms/min) was studied in 9 dogs with quinidine induced TdP. Isoproterenol significantly shortened basic cycle length, corrected QT interval, effective refractory period (ERP) and dispersion of ERP and increased ERP/QT. Isoproterenol prevented the occurrence of TdP in all dogs. These findings suggest that isoproterenol decreases the dispersion of ventricular refractoriness and may be useful in the treatment of drug induced TdP.

Animals↗
PubMed1991

[Efficacy of isoproterenol, magnesium sulfate and verapamil for torsade de pointes].

The efficacy of isoproterenol, MgSO4 and verapamil for torsade de pointes was evaluated in 60 dogs. Torsade de pointes was induced in 28 out of 60 dogs (46.7%) by ventricular stimulation after administration of quinidine sulfate (30 mg/kg). The electrophysiologic effect of isoproterenol (0.5 micrograms/min drip infusion) was studied in 9 dogs with torsade de pointes, in 9 dogs with MgSO4 (30 mg/kg), and in 10 dogs with verapamil (0.1 mg/kg bolus injection followed by 0.01 mg/kg/min drip infusion). If the first dose of these drugs was ineffective, ventricular stimulation was performed after the additional administration of the same dose. Isoproterenol significantly decreased QTc, ERP and dispersion of ERP but increased ERP/QT. MgSO4 significantly increased ERP and ERP/QT, however dispersion of ERP did not change. Verapamil induced no electrophysiologic changes in ventricular refractions . Isoproterenol prevented the occurrence of torsade de pointes in all dogs (100%), MgSO4 in 7 of 9 dogs (77.8%, 30 mg/kg in three and 60 mg/kg in four) and verapamil in 4 of 10 dogs (40%, 0.1 mg/kg in two and 0.2 mg/kg in two). These findings suggest that isoproterenol and MgSO4 increased ERP/QT, showing one of their antiarrhythmic effects. It also shows that isoproterenol and MgSO4 may be useful in the treatment of torsade de pointes.

Animals↗
PubMed1991

[A case of left atrial myxoma in the elderly (77-year-old)].

We reported a case of a 77-year-old female, whose left atrial myxoma with a cyst, which had been identified by 2D echocardiography, was successfully resected. Apart from echocardiogram-revealed tumor hemorrhages in atrial myxomas, reports of echo-lucency within cardiac tumors are considerably rare. She was successfully operated on, and the section through the tumor specimen showed a cyst with a diameter of 10 mm, that corresponded to the echo-lucencies noted on the 2D echocardiogram. Even in an elderly patient, surgical treatment of left atrial myxoma offers excellent results with low morbidity and low mortality.

Aged↗
PubMed1990

Effect of magnesium sulfate on ventricular refractoriness and its efficacy for torsade de pointes.

The effect of magnesium sulfate on ventricular refractoriness and its efficacy for torsade de pointes (TdP) were studied in nineteen dogs. After the administration of quinidine sulfate (30 mg/kg), TdP was induced by ventricular pacing in ten of 19 dogs (52.6%), polymorphic ventricular tachycardia in seven (36.8%), ventricular fibrillation in two (10.5%). Quinidine sulfate caused significant increases in QTc interval, ventricular effective refractory period (ERP) and dispersion of ERP(dERP), and decrease in ERP/QT. Magnesium sulfate significantly increased ERP (p less than 0.01), but it did not change QT interval, resulting in significant increasing of ERP/QT (0.41 +/- 0.05 to 0.61 +/- 0.05, p less than 0.01). It decreased dERP but not significantly. Magnesium sulfate prevented the induction of TdP in eight of 10 dogs (80.0%) (30 mg/kg in four and 60 mg/kg in four). In conclusion, magnesium sulfate has value as first aid therapy for drug-induced TdP. If patients have ischemic heart disease or hypertension, we recommend infusion of magnesium for the initial therapy of TdP.

Animals↗
PubMed1990

[Non-ketotic hyperosmolar diabetic coma in neurosurgical cases; review of 7 cases].

Neurosurgical patients with non-ketotic hyperosmolar diabetic coma (NHC) in our institution were analysed retrospectively. Seven cases were diagnosed as NHC being 0.47% of the number of inpatients in the last 5 years. The age ranged from 60 to 72 years old (mean 65) and there were 6 males and 1 female. Only 2 patients (29%) had a clear past history of diabetes mellitus. Prior to the NHC, systemic infection was present in 2 cases. Intravenous hyperalimentation (IVH) was performed in 5 cases, glycerol osmotherapy in 3 cases, diphenylhydantion therapy in 3 cases and tube feeding in 2 cases. The overall mortality rate in our series was 71% (5 cases), of which 2 cases died within 2 days due to cardiopulmonary failure, and 3 cases in the chronic stage died due to disseminated intravascular coagulopathy (DIC), or due to renal failure. The prognosis of NHC in neurosurgical patients is generally bad because of the presence of consciousness disturbance prior to the onset of NHC, which may mask the symptoms occurring from the NHC. Other predisposing factors could be systemic infection, IVH or tube feeding, and osmotic agents which are frequently used in neurosurgical patients. There was a tendency for NHC to occur predominantly in the chronic stage after the blood sugar had returned to normal range from the hyperglycemic state in the acute stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗