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Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 631 records · Page 35Linked to original sources
PubMed1991

Urate oxidase activity and copper content in the liver of macular mutant mouse, a model animal for human congenital copper deficiency, Menkes' kinky hair disease.

The macular mouse is an X-linked recessive inherited mutant and is considered to be a model for human congenital copper deficiency, Menkes' kinky hair disease. The activity of urate oxidase, which has been believed to be a copper enzyme, and copper content in the liver of the mutant mouse were determined. The oxidase activity was maintained at normal level even though there was very low level of copper present in the liver through days 7 to 14. Copper administration increased the copper content in the liver to the normal level, but did not affect the oxidase activity.

Animals↗
PubMed1991

Problems of protocol practice in Japan.

With progress in medical knowledge and in the technology of medical care, the contents of medical practice have become increasingly complicated year by year. The protocol practice (clinical algorithms or scheduled care) has been experimentally employed as one of medical-practice systems aimed at providing better medical care and maintaining its high standards. In the protocol practice the criteria for decision-making, which are clinically employed, are precisely made up in advance so that practice will be performed systematically. The WHO has recommended this protocol practice as a medical-care system appropriate for realizing clinical experiments. In recent years a number of clinical studies have been born from the protocol practice and, thus, it has been considered to be a formula for conducting clinical experiments tolerant of scientific criticism. The protocol practice, however, since it is difficult to conduct smoothly, has not yet been settled. This study aims at considering what we should do to make the protocol practice system settled through the observation of pitfalls in the course of its application.

Clinical Medicine↗
PubMed1991

A 24-hour ordering system for clinical examinations.

We have developed a 24-hour ordering system for clinical examinations, making use of the features of multi-function workstation (IBM5550) which performs two functions both in an on-line terminal and in a personal computer. It is used as an on-line terminal for the host computer (IBM4381) in day time. At night or on holiday, it is used as a stand-alone type personal computer to order clinical examinations. For this purpose, basic information of the inpatients (patient number, name, sex, date of birth, clinic, ward) are transferred from the host computer to the disket in the workstation in the evening when host computer finished on-line service. A physician can input the patient number followed by examination items using the touch panel according to the dialogue type guides written in Chinese character. Then, specimen label, list of ordered tests and an order form are printed out instantly. The date (patient number, examination items, identification number of the specimen, etc.) stored in the disket in the workstation at night are transferred from workstation to the host computer next morning. The host computer merges the information ordered in day time and at night and supplies working documents for examination (worksheets, master log, etc.) to technicians. Thus physicians can order examinations all day long using workstation, which make it possible to spare the time.

Clinical Laboratory Information Systems↗
PubMed1991

[Analysis of human papillomavirus type 16 E6/E7 mRNA in cervical cancers and precancerous lesions by means of the polymerase chain reaction with reverse transcriptase reaction].

We analyzed HPV-16 E6/E7 mRNA in human uterine cervical carcinomas and cervical intraepithelial neoplasias (CINs) by polymerase chain reaction (PCR) with reverse transcription (RT-PCR). Simultaneously total RNA and DNA were extracted from 6 cervical carcinomas, 14 CINs and 2 normal cervical tissues by the guanidium isothiocyanate/CsCl method. HPV-16 DNA was detected in 3 cervical carcinomas and 6 CINs. HPV-16 E6/E7 transcripts were detected in all HPV-16 DNA positive cervical carcinomas and CINs. In 2 cervical carcinomas and 5 CINs, 2 spliced E6 mRNA (E6*I and E6*II) and full length E6 mRNA were detected. In one cervical carcinoma and in one CIN, only full length E6-E7 mRNA was detected. Sequence analysis of cloned PCR products showed that both transcripts were generated by splicing out an intron in E6, from nucleotides (nt) 226 to 409 in E6*I and from nt 226 to 526 in E6*II. There was no significance difference in HPV-16 E6/E7 mRNA patterns between cervical carcinomas and CINs. This sensitive RT-PCR technique was available for analysis of HPV-16 mRNA in the small specimens.

Carcinoma, Squamous Cell↗
PubMed1991

[Postoperative brain metastasis from esophageal carcinomas: report of 4 cases].

Out of 83 cases received resection of primary esophageal lesion, 4 patients were affected by metastatic brain tumor which was reported to rarely occur. All 4 patients had symptoms of central nervous system. Three of them were diagnosed by CT and the other one at autopsy. All of the primary esophageal tumors were advanced and of histological stage III or IV. They located in the middle or lower thoracic esophagus. Brain tumor of one case was removed and this case was of progression free at the last presentation. The other 3 cases were not received resection of metastatic brain tumors and died. All of 3 were autopsied and two of them had no metastasis in the lung. Therefore, it was considered that these hematogenic metastases were not through lung filtrations but through other routes, which Batson O. V. experimentally proved and designated as vertebral vein system in 1940. It is concluded that aggressive surgical intervention to metastatic brain tumors was beneficial with regard to prognosis for cases without other metastatic lesions.

Aged↗
PubMed1991

Detection of hepatitis B virus DNA in paraffin-embedded liver tissues in chronic hepatitis B or non-A, non-B, hepatitis using the polymerase chain reaction.

We developed a polymerase chain reaction assay for the direct detection of hepatitis B virus in paraffin-embedded liver tissue and applied this assay to determine whether hepatitis B virus DNA exists in livers with chronic hepatitis non-A, non-B. Fifty five liver biopsy samples were studied: 11 from patients with HBeAg-positive chronic hepatitis (paraffin-embedded) and 44 from patients with chronic hepatitis non-A, non-B (21 paraffin-embedded; 25 fresh frozen). Thirty three (75%) of the non-A, non-B cases were positive for hepatitis C virus antibodies. Approximately 1 to 10 ng of DNA was extracted from the paraffin-embedded tissue and amplified using oligonucleotide (23-mer) primers specific for the S gene (positions 261 to 692). The beta-globin gene was used as an internal control for sensitivity because this is a single copy gene and allows for relative quantification. In each of the chronic hepatitis B livers, the expected 432-base-pair amplification product for hepatitis B virus DNA and beta-globin gene product were both detected. On the other hand, in the 21 paraffin-embedded chronic hepatitis non-A, non-B livers, no hepatitis B virus DNA was detected, although beta-globin gene was observed in all. Furthermore, in all 25 frozen non-A, non-B livers, beta-globin gene was observed, but no hepatitis B virus band was seen. The limit of detection of hepatitis B virus DNA by this method was estimated to be one genomic copy of hepatitis B virus DNA per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Neural plasticity after neonatal hypoxic and ischemic insult in rats].

Rats with huge porencephaly occupying the left cerebral hemisphere were used for this study. Porencephaly was caused experimentally by the ligation of the left common carotid artery and subsequent hypoxic exposure at the age of 7 days. A large band of horseradish peroxidase (HRP) positive fibers was found crossing at the pyramidal decussation to reach the contra-lateral corticospinal tract and the deeper part of the funiculus, in the cervical cord. However, a small band of HRP positive fibers was noticed to reach the ipsilateral corticospinal tract without crossing at the pyramidal decussation. This result indicates that the developing pyramidal neurons in the right hemisphere carry the plasticity even after suffering from considerable hypoxia.

Animals↗
PubMed1991

[Early diagnosis of neonatal neurological disorders].

Main diagnostic points on the clinical signs and symptoms of various neurological disorders during the neonatal period and early infancy are briefly mentioned. Application, diagnostic values and limitation of various diagnostic measures including US, CT and MRI are then discussed.

Electrophysiology↗
PubMed1991

[The development of an antimony electrode with a built-in thermocouple and a temperature-compensated pH meter for the determination of intramyocardial pH during open-heart surgery].

Myocardial acidosis as reflected in pH measured by a glass (G) electrode during ischemic arrest may adversely affect postoperative cardiac function. However, (G) is slow in response and fragile. We report the development of an antimony electrode (Sb) and a pH meter based on our investigation and the results of their clinical application. As a biological material, CPD blood was chosen and subjected to a series of experiments determine its pH by (Sb) and (G). There was a small (within 0.1), but statistically significant difference in pH between (Sb) and (G). To simulate myocardial cooling during operation, CPD blood was cooled and its pH measured by (Sb) and (G). (Sb) showed significantly different behaviour from (G), i,e, the pH tended to fall with the falling temperature, whereas with (G) it tended to rise as had been previously known. The thermodynamic property of (Sb) was checked in appropriate buffer solutions by varying their temperatures. There was an almost linear correlation between EMF by (Sb) and the temperature of the buffer solutions (1 mV/1 degree C, or 0.017 pH/1 degree C). Accordingly, a pH meter incorporating an electronic circuit compensating for the temperature-depending EMF and a (Sb) with a built-in-thermocouple were constructed. Utilizing the new apparatus, CPD blood was again tested and it was proved that the new electrode and the pH meter worked in similar manner to (G). The new apparatus was applied to a series of measurement of intramyocardial pH during open-heart surgery and the results compared with that previously obtained by (G). There were no significant differences either between control pH or rate of its fall in the initial 10 minutes. following aortic cross-clamping and the administration of the cardioplegic solution. It is concluded that although (Sb) is not as accurate as (G), it is a reasonable alternative for the determination of the intramyocardial pH during open-heart surgery.

Cardiac Surgical Procedures↗
PubMed1991

[A successful surgical treatment of cor triatriatum with VSD, PDA and CoA].

A successful repair of cor triatriatum with VSD, PDA and CoA is reported. A two-month-old boy was admitted for evaluation of growth failure and cyanosis. Physical examination on admission revealed systolic murmurs at left sternal border. Chest X-ray showed increased pulmonary vascularities without cardiomegaly. Echocardiography showed abnormal wall in left atrium with VSD, PDA and CoA. An emergency operation consisting of patch closure of VSD, ligation of PDA and resection of the anomalous left atrial membrane were performed. At postoperative course, an episode of pulmonary hypertension crisis happened. But the patient tolerated this episode and survived.

Aortic Coarctation↗
PubMed1991

Difference in the susceptibility of two phenobarbital-inducible forms, P450IIB1 and P450IIB2, to thyroid hormone- and growth hormone-induced suppression in rat liver: phenobarbital-inducible P450IIB2 suppression by thyroid hormone acting directly, but not through the pituitary system.

Suppression of two major phenobarbital-inducible cytochrome P-450s, P450IIB1 and P450IIB2, by thyroid hormone was studied and compared with growth hormone (GH)-induced suppression in rats in vivo and hepatocytes in primary culture in vitro. Treatment of adult male rats with 50 micrograms/kg triiodothyronine (T3) reduced the constitutively expressed amounts of P450IIB1 (up to 1 pmol/mg of protein) and P450IIB2 (2-5 pmol/mg of protein) to 42% and 3% of their levels in nontreated controls. Thyroidectomy increased the hepatic contents of P450IIB2 (to levels of 50-80 pmol/mg of protein) and, to a lesser extent, P450IIB1 (1-5 pmol/mg of protein) in male and female rats. Supplement of T3 to thyroidectomized rats reversed the increased contents to levels similar to those observed in normal rats. Hypophysectomy also increased both P450IIB1 and P450IIB2 protein, and their levels in both sexes were similar to that of P450IIB2 in thyroidectomized rats. Treatment of hypophysectomized rats with T3 as well as human GH suppressed hepatic contents of P450IIB1 and P450IIB2. In a hepatocyte culture including 2 mM phenobarbital, T3 and GH suppressed both P450IIB1 and P450IIB2. Other thyroid hormone derivatives, including thyroxine, D-T3, and reversed T3, also showed suppressive effects, in parallel with the potencies for their stimulatory action that have been reported. These results indicate that thyroid hormone may suppress both P450IIB1 and P450IIB2 by a direct effect on the liver, but not by an indirect effect through the modulation of pituitary GH synthesis. The high susceptibility of hepatic P450IIB2 to thyroid hormone-induced suppression also indicates that constitutive and phenobarbital-induced levels of P450IIB2 are suppressively regulated preferentially by thyroid hormone, in contrast to the high susceptibility to GH of P450IIB1 in rat liver. In addition, a difference in the suppressive mechanisms of thyroid hormone and GH was suggested by the difference in susceptibility to cycloheximide.

Animals↗
PubMed1990

A novel enzymatic decarboxylation of oxalic acid by the lignin peroxidase system of white-rot fungus Phanerochaete chrysosporium.

Oxidation of veratryl alcohol by lignin peroxidase (LiP) was potently inhibited by oxalic acid. The inhibition analysis with Lineweaver-Burk plots clearly showed that the type of inhibition is non-competitive. The enzymatic oxidation of veratryl alcohol in the presence of 14C-oxalic acid yielded radioactive carbon dioxide. The results indicate that the apparent inhibition of LiP is caused by reduction of the veratryl alcohol cation radical intermediate back to the substrate level by oxalate, which is concomitantly oxidized to carbon dioxide.

Benzyl Alcohols↗
PubMed1990

Role of sugar chains in the in vitro biological activity of human erythropoietin produced in recombinant Chinese hamster ovary cells.

Human erythropoietin contains three Asn-type and one mucin-type sugar chains. That the branching structure of the outer portion of Asn-type sugar chains is correlated to its biological activity in vivo has been reported recently (Takeuchi, M., Inoue, N., Strickland, T. W., Kubota, M., Wada, M., Shimizu, R., Hoshi, S., Kozutsumi, H., Takasaki, S., and Kobata, A. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 7819-7822). In this study, the effect of trimming of sugar chains on the biological activity in vitro of this hormone was examined by using several glycosidases. Human erythropoietin produced by recombinant Chinese hamster ovary cells showed three times higher activity after desialylation. The activity was not changed significantly by further removal of the mucin-type sugar chain from the hormone, indicating no contribution of this type of sugar chain to the activity of erythropoietin in vitro. Sequential removal of galactose and N-acetylglucosamine from the outer chain moieties of the desialylated Asn-type sugar chains raised the activity of the hormone up to four and five times the intact erythropoietin, respectively. The activation effect was diminished slightly by further removing alpha-mannosyl residues and to a great extent by removing beta-mannosyl residues from the core portions of the Asn-type sugar chains. N-Glycanase digestion of intact erythropoietin resulted in almost complete loss of the activity in vitro. These results indicate that the core portion of the Asn-type sugar chains is necessary for erythropoietin to express its full biological activity in vitro and suggest that removal of the core portion of the sugar chains destroys the active conformation of erythropoietin.

Animals↗
PubMed1990

Hypoxia prevents seizures and neuronal damages of the hippocampus induced by kainic acid in rats.

The effects of hypoxia on the epileptic seizures and neuronal damages induced by kainic acid were studied in rats using hypoxic chamber equipment. Rats treated with kainic acid and placed in atmospheric pressure showed typical limbic seizures and regressive neuronal changes in CA3 and CA4 of the hippocampus, while those kept in a hypoxic chamber with 8.5% O2 and 91.5% N2 showed moderate hypoxia and a slight decline of mean arterial blood pressure. In these hypoxic rats, seizures were completely prevented and there was remarkably less regressive neuronal injury of the hippocampus. Thus hypoxia has a rather ameliorative effect on the occurrence of seizures and excitotoxic neuronal injuries induced by kainic acid. The contribution of oxygen radicals and endogenous adenosine to preventing excitotoxic neuronal damages by kainic acid was discussed.

Animals↗
PubMed1990

Diethylcarbamazine, antifilarial drug, inhibits microtubule polymerization and disrupts preformed microtubules.

The effect of diethylcarbamazine (DEC) on microtubules was studied by using microtubule protein prepared from porcine brain. DEC inhibited assembly of microtubules and disassembled preformed microtubules in vitro. When the reassembled or disassembled products were examined in the presence of DEC by electron microscopy, ribbon-microtubules were frequently observed. Subsequently, the effect of DEC on the cytoplasmic microtubules complex was studied. The cells used in our study were LLC-MK2. DEC inhibited proliferation of these cells, and cells grown in the presence of DEC were likely to separate from each other and became round in shape. Immunofluorescence microscopy revealed that the cells exposed to DEC were devoid of the delicate pattern of the cytoplasmic microtubule complex.

Animals↗