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Biomedical subjects

H Takano

Publications and source records attributed to H Takano.

At least 415 records · Page 23Linked to original sources
PubMed1990

Newly developed myocardial imaging by using single photon emission computed tomography (SPECT).

Thallium myocardial imaging is a useful technique to evaluate myocardial perfusion and myocardial viability in ischemic heart disease. However, myocardial imaging using single photon emission computed tomography (SPECT) and gamma-emitting radiopharmaceuticals has been recently developed for more precise evaluation of myocardial infarction and ischemia. The present study evaluates animal experiments and the clinical applications of these new myocardial imaging techniques. Areas considered on 1) myocardial necrosis assessed using 111In-antimyosin, 2) myocardial fatty acid metabolism assessed using 123I-beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and 3) myocardial sympathetic neural activity assessed using 123I-metaiodobenzyl guanidine (MIBG). Dual energy SPECT using these new agents and thallium gives precise characterization of the myocardial tissue in the infarcted and ischemic area.

3-Iodobenzylguanidine↗
PubMed1990

Seasonal distribution of bovine coccidia in beef cattle herd in the university farm.

Fecal samples (2,019) from cattle in the university farm, Tohoku University, were examined for coccidian oocysts from April 1986 to January 1987, and 19.3% of them was positive for Eimeria spp. Thirteen Eimeria species were identified. Eimeria bovis (25.7%) was the most dominant species, followed by E. auburnensis (17.6%), E. canadensis (14.5%), E. alabamensis (9.7%), E. ellipsoidalis (8.1%), E. zuernii (7.0%), E. bukidnonensis (5.4%), E. brasiliensis (3.9%), E. cylindrica (1.3%), E. illinoiensis (0.4%), and E. pellita (0.2%). Fecal samples positive for coccidial oocysts amounted to 12.9% and 26.7% on average during grazing on pasture and loose housing, respectively.

Animals↗
PubMed1990

Histologic changes in the mouse epididymis fixed in the abdominal cavity.

Histologic changes in the mouse epididymides were examined by light and electron microscopy 1, 3, 6 and 10 weeks after surgical fixation of the testes and epididymides to the internal abdominal wall at 2 months of age. In the epididymides subjected to the cryptorchid surgery, the principal cells in the segment next to the initial segment became taller, the nuclei were translocated to a higher position, and the widened infranuclear cytoplasm turned pale. The supranuclear cytoplasm showed a decrease in PAS stainability. Electron microscopy revealed that the infranuclear cytoplasm, which is occupied by small vesicular endoplasmic reticulum in the normal cells, was filled with distended rough endoplasmic reticulum. These changes first appeared one week after operation, further developing with time. Similar changes were observed when the epididymis was in the abdominal position with the testis in the scrotal position, or with the efferent duct ligated to block the testicular fluid flow into the epididymis. It is suggested that the epididymal changes recorded in this paper are induced by the elevation of temperature caused by the translocation from the scrotum to the abdomen.

Abdomen↗
PubMed1990

[Estimating organ doses of dental students in dental radiographic exercises].

To estimate doses absorbed in organs of dental students in the exercises of dental radiography, we measured the average organ doses of the dental radiographic examinations and sent out questionnaires about the radiographic exposure of the dental students. We selected five organs in the head and neck regions: lens of the eye, parotid gland, submaxillary gland, thyroid and pituitary fossa. The dose determinations were made for the full mouth intra-oral radiography with 10 films, and panoramic radiography and cephalometric radiography. Doses for all organs, except for the parotid gland, were widely distributed with one peak. The highest average dose per dental student was about 5000 microGy for the parotid gland, about 2900 microGy for the submaxillary gland, about 900 microGy for the lens of the eye, about 480 microGy for the thyroid and about 140 microGy for the pituitary fossa. Dose limits for dental students in such exercises have not been yet established. But the organ doses, especially for the parotid gland, appear very high. To reduce exposure in the exercises and to protect the dental students from excess exposure, we need to reconsider the study of dental radiographic techniques.

Adult↗
PubMed1990

[Statistical analysis of nuclear medicine in the Higashi Nippon Gakuen University Dental Hospital].

The number of radionuclide in vivo tests carried out at the Higashi Nippon Gakuen University Dental Hospital was statistically analyzed and discussed. The subjects were all patients admitted to the Division of Nuclear Medicine during the seven years between 1981 and 1989. The total number of the patients included those introduced through medical facilities in Toubetsu-cho and others. The results of this analysis were as follows: 1) The proportion of the first time patients admitted to the Higashi Nippon Gakuen University Dental Hospital was only 11 percent of all patients. 2) Cases of radionuclide in vivo tests at the Higashi Nippon Gakuen University Dental Hospital decreased in number, annually. However the proportion of tumor scintigraphy and bone scintigraphy increased gradually.

Female↗
PubMed1990

[Recovery of severely decompensated hearts with a left ventricular assist device].

We evaluated the limits of recovery of decompensated hearts experimentally and clinically and studied the problems of applying a left ventricular assist device (LVAD). In the chronic experiments, 16 adult goats were studied as follows: Group I consisted of seven with left ventricular infarction in a 70-80% area of the free wall induced by the multiple-ligation method; Group II, three with infarcted areas larger than 80% of the free wall; Group III, three with a 30 min anoxic arrest, and Group IV, a 45-min anoxic arrest. An LVAD was applied in all goats, and a right ventricular assist device was applied simultaneously for two goats in Group IV. Clinically, 21 patients receiving treatment with an LVAD from December 1982 to September 1988 in our center were examined. No goat in Groups II and IV could be weaned from the LVAD. Thus, the severity of artificial heart failure in Groups I and III was considered to be the limit for accomplishing restoration. In successfully-weaned cases, both in experimental and clinical settings, periods of LVAD therapy with or without IABP were less than two weeks, which was thought to be the upper time limits for LVAD application. All but one successfully-weaned patients were alive in the experiment, while clinically many patients died of multiple organ failures regardless of the results of the LVAD assistance. Analysis of data suggested that the difference was caused by the durations of the LVAD applications and weanings, the degree of right ventricular failure, the doses of catecholamine used, and the systemic care afforded, especially during tracheal intubation.

Animals↗
PubMed1990

[Congenital atresia of the left main coronary artery ostium--a case suffering from ventricular tachycardia].

A case of congenital atresia of the left main coronary ostium suffering from ventricular tachycardia underwent coronary artery bypass operation. The patient was 17 years old boy. When he was 9 years old he visited our department for the purpose of examining cardiac disease. The diagnostic impression was mitral regurgitation. At 16 years old he suddenly complained tachycardia during exercise. He admitted to our hospital and the tachycardia was proved to be ventricular tachycardia. Left ventriculogram demonstrated a small range of akinesis at the left ventricular apex. And coronary cineangiogram revealed atresia of the left main coronary artery. The left coronary artery was perfused with collateral circulations from right coronary artery. Electrophysiological study was performed. The ventricular tachycardia could be reproducibly initiated and terminated by programmed stimulation. The catheter endocardial mapping was also performed. The source of ventricular tachycardia was supposed to be at the left ventricular apex. At 18 years old coronary artery bypass operation was performed. Internal mammary artery graft was placed to the left anterior descending artery and a saphenous vein graft was placed from the ascending aorta to the left circumflex artery. A small size of myocardial infarction was recognized at the left ventricular apex. And epicardial mapping revealed that the source of arrhythmia was the same region as the myocardial infarction was recognized. Endocardial resection or cryoablation was not performed. Post-operative study was performed 8 months after surgery. The graft flow of the internal mammary artery to the left anterior descending artery was not sufficient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[A rare case of congenital tricuspid stenosis treated with modified Fontan operation].

A rare case of congenital tricuspid stenosis treated with modified Fontan operation was reported. The patient was 13 years old boy and his chief complaint was cyanosis. Cyanosis appeared in his neonatal period and squatting developed in his childhood. He underwent Blalock's shunt operation at 5 years of age. His exercise tolerance was limited at the admission for the radical operation. Angiocardiography showed the annular stenosis of tricuspid valve and the moderate hypoplasia of right ventricle. The right ventricular volume was 56 ml (equivalent to 35% of the normally expected right ventricular volume) and the diameter of tricuspid annulus was 13 mm (equivalent to 58% of the normally expected diameter). Atrial septal defect was associated with but pulmonary stenosis did not exist. His left ventricular function was good and pulmonary vascular resistance was not raised. A diagnosis of tricuspid stenosis was made and Fontan's repair was considered to be possible for his correction. Operative findings showed normal architecture of tricuspid valve with the three leaflets but tricuspid annulus was narrow. Tricuspid valve stenosis was considered to be caused by the hypoplasia of tricuspid ring and surgical dilatation was found to be difficult. Therefore, modified Fontan operation (RA-RV connection) was performed. His cyanosis disappeared and exercise tolerance was improved after the operation. Cardiac catheterization and angiocardiography were performed 8 months and 28 months after the operation. His righ ventricular volume was increased to 123 ml (equivalent to 57% of the normally expected volume) followed by RA-RV connection.

Adolescent↗
PubMed1990

[Role of oxygen-derived free radicals for antitumor effects of intra-arterial injection with adriamycin].

This study examined the role of oxygen-derived free radicals for antitumor effects of intra-arterial injection with adriamycin (ADR). The effect of chemoembolization using ADR and degradable starch microspheres (DSM) was studied in rabbits with VX2 carcinoma of the hind leg. The tumor growth in rabbit treated with chemoembolization (ADR: 3.0 mg/kg + DSM 20mg/kg) was completely suppressed, but the therapeutic effect of chemoembolization combined with dimethylsulfoxide (DMSO) was reduced. On the other hand, the therapeutic effect of chemoembolization combined with superoxide dismutase and catalase was not reduced. These results indicate that the production of oxygen-derived free radicals, especially hydroxyl radical in the cancer cell, plays an important role in the antitumor effect of adriamycin.

Animals↗
PubMed1989

The direct activation of human multidrug resistance gene (MDR1) by anticancer agents.

Enhanced expression of a multidrug-resistance gene (MDR1) is observed in some cancer patient, but any regulatory mechanisms of MDR1 gene expression in this phenomenon is not yet known. In this study, the regulation of MDR1 gene was analysed by transient expression assays in the presence of anticancer agents. We found that MDR1 promoter could be activated directly on the addition of anticancer agents including vincristine, daunomycin, adriamycin and colchicine. The results suggest that the level of MDR1 mRNA expression is associated with previous chemotherapy, including drugs that select the multidrug resistance phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1989

Primary structure of bacteriophage M2 DNA polymerase: conserved segments within protein-priming DNA polymerases and DNA polymerase I of Escherichia coli.

Bacteriophage M2 encodes its own DNA polymerase which catalyses the formation of a primer protein-5'dAMP initiation complex for DNA replication. To understand the relation of structure to function of this 'protein-priming DNA polymerase', we have determined the nucleotide sequence of the M2 DNA polymerase-encoding gene (gene G). The deduced 572-amino acid sequence of M2 DNA polymerase shows 82.3% overall homology to that of phi 29 DNA polymerase. A homology search with the mutation data matrix revealed that six segments (A-F, from the N terminus) of M2 and phi 29 DNA polymerases are homologous with the sequence of Escherichia coli DNA polymerase I (PolI). Segments D and F coincide with the conserved segments of many other DNA polymerases. Therefore, M2 and phi 29 DNA polymerases have structural features, at least in the conserved segments, similar to those of PolI and other DNA polymerases. Based on the homology with PolI and the location of the mutations for aphidicolin resistance and nucleoside analog resistance of M2, phi 29 and herpes simplex virus type-1 DNA polymerases, we propose that segments A-D of the M2 and phi 29 DNA polymerases constitute a structure which forms the cleft for holding template DNA and that segment D is a region for interacting with dNTP.

Amino Acid Sequence↗
PubMed1989

[Study of multiregression analysis on NK activities and related clinical factors in patients with head and neck neoplasms].

NK activity in patients with head and neck neoplasms treated with radiation and chemotherapeutics was studied on the influence of 19 factors by using the method of multiregression analysis. Of these factors, BUN, WBC, the size of radiation portal, chemotherapy, radiation doses, total protein (T.P.), age and GOT were significantly influenced on the fluctuation of NK activity (p less than 0.05). In the studies of the size of radiation portal and its doses, NK activity showed a tendency to increase with radiation dose in small size of radiation portal and a tendency to reduce in large size of it.

Adult↗
PubMed1989

Solitary Peutz-Jeghers type polyp of the stomach in the absence of familial polyposis coli in a teenage boy.

We treated a male teenager with a solitary gastric Peutz-Jeghers type (hamartomatous) polyp showing neither mucocutaneous pigmentation nor inheritance. X-ray studies of the upper gastro-intestinal tract, small intestine and barium enema revealed a solitary thumb tip-sized polypoid mass in the posterior wall of the gastric body, with no evidence of any associated lesion. Histologically, the polypoid mass showed typical features of a Peutz-Jeghers type (hamartomatous) polyp. This may be the first documentation of a "solitary" gastric Peutz-Jeghers type polyp, in the absence of familial polyposis coli and mucocutaneous pigmentation.

Adenomatous Polyposis Coli↗
PubMed1989

Motor evoked potential monitoring during upper cervical spine surgery.

Motor evoked potential (MEP) produced by transcranial electrical stimulation was recorded from an epidural electrode in 20 consecutive patients during upper cervical spine surgery. In 5 patients, transient attenuation to approximately 50% followed by complete recovery was observed, and no neurologic deficit was noted. One patient had complete loss of MEP and was left a respiratory quadriplegic. In 2 cases, MEP amplitudes increased after tumor extirpation and remarkable remissions were observed. The MEP correlated with clinical outcomes and was a useful monitoring technique for upper cervical spine surgery, free of complication. In cat experiments designed to analyze conducting pathways, the maximal amplitude of the initial spike of MEP existed in the ventromedial spinal cord, which contains the extrapyramidal tracts. Motor evoked potential was proven to reflect motor function based on the spinal cord compression study.

Animals↗
PubMed1989

Altered expression of epidermal growth factor receptor gene in a classical multidrug-resistant variant of a human cancer cell line, KB.

A variant clone resistant to high doses of colchicine (KB-C1) derived from human cancer KB cell line is resistant to various anticancer agents. The KB-C1 cells were much more resistant to epidermal growth factor and a chimeric toxin, EGF-Pseudomonas exotoxin (PE), than the parental KB cells. KB-C1 cells have decreased numbers of EGF-receptors, though the affinity of the receptors is similar to that in the parental KB cells. A drug-sensitive revertant (C1-R2) partially recovered its EGF-receptor activity. Northern blot analysis showed a decreased level of EGF-receptor mRNA in KB-C1 cells, while the multidrug-resistance gene, mdr-1, was expressed at very high levels in KB-C1 cells, but not in KB or C1-R2 cells. The drug-resistant cells were less tumorigenic than the parental cells when injected into nude mice. A decreased expression of EGF-receptor in these cells may be one of the pleiotropic properties of multidrug-resistant cells and may perhaps represent the basis for their reduced tumorigenicity.

Animals↗