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Biomedical subjects

M Takagi

Publications and source records attributed to M Takagi.

At least 775 records · Page 43Linked to original sources
PubMed1986

Proliferative myositis and fasciitis. Report of five cases with an ultrastructural and immunohistochemical study.

Cases of proliferative myositis and fasciitis were studied immunohistochemically and ultrastructurally for further understanding of the nature of ganglion cell-like giant cells. Blood coagulation factor XIIIa, fibronectin, myoglobin, myosin, CPK MM, and alpha-1-antichymotrypsin were detected in three cases of proliferative myositis and two cases of proliferative fasciitis by the avidin-biotin-peroxidase complex method. Factor XIIIa (a fibrin-stabilizing factor) and fibronectin were strongly positive in the giant cells, but not in striated muscle fibers. A small quantity of myosin was demonstrated in the giant cells, but myoglobin and CPK MM were never demonstrated in these cells. No alpha-1-antichymotrypsin was demonstrated in the giant cells. One case of proliferative myositis showed ultrastructural features suggestive of fibroblast rather than muscle cell or histiocytic origin. Strongly positive factor XIIIa in the giant cells is suggestive of the fact that they are active fibroblasts.

Aged↗
PubMed1986

Construction of a host-vector system in Candida maltosa by using an ARS site isolated from its genome.

To construct a host-vector system in an n-alkane-assimilating yeast, Candida maltosa, the isolation of an ARS site from its genome which replicates autonomously in C. maltosa was attempted. Leu- mutants of C. maltosa were transformed with a gene library prepared by using YEp13 (LEU2+) as a vector, and Leu+ transformants were obtained at a high frequency. A plasmid named pCS1 was isolated from the recipient cells. pCS1 contained a 6.3-kilobase (kb) fragment of the C. maltosa genome, and a 3.8-kb fragment with ARS activity was subcloned and designated the TRA (transformation ability) region. Vectors (pTRA1 and pTRA11) for C. maltosa J288 were constructed that contained this 3.8-kb fragment, pBR322, and the LEU2 gene of Saccharomyces cerevisiae. Transformation of C. maltosa J288 with these plasmids was successful by both spheroplast and lithium acetate methods. Southern blot analysis suggested that the copy number of pTRA1 in C. maltosa was between 10 and 20, and it was stably maintained during growth without selective pressure in the medium. It was also found that these vectors could transform S. cerevisiae leu2- to LEU2+, suggesting that the TRA region contained an ARS site(s) that was specific not only for C. maltosa but also for S. cerevisiae.

Candida↗
PubMed1986

Cloning in Saccharomyces cerevisiae of a cycloheximide resistance gene from the Candida maltosa genome which modifies ribosomes.

We have previously shown that cycloheximide resistance can be induced in a strain of Candida maltosa by modifying ribosomes (M. Takagi, S. Kawai, Y. Takata, N. Tanaka, M. Sunairi, M. Miyazaki, and K. Yano, J. Gen. Appl. Microbiol. 31:267-275, 1985). The present paper describes the cloning of the gene involved in this resistance (designated RIM-C for ribosome modification by cycloheximide) by using a host-vector system of Saccharomyces cerevisiae.

Candida↗
PubMed1986

Cholinergic influence of the laterodorsal tegmental nucleus on neuronal activity in the rat lateral geniculate nucleus.

The effect of stimulation of the laterodorsal tegmental nucleus (LDT) on the activity of single neurons in the dorsal lateral geniculate nucleus was studied in rats anesthetized with urethan. The LDT is the largest aggregation of cholinergic neurons in the brain stem that project to the thalamus, and in the rat is sufficiently compact to permit its localized stimulation. Position of stimulating electrodes was confirmed on histological sections processed with NADPH-diaphorase histochemistry, which in the rat brain stem selectively stains cholinergic neurons. Repetitive stimulation of the LDT at 200 Hz increased the firing rate of substantially all geniculate relay neurons and weakly depressed the activity of intrinsic interneurons. These effects usually occurred within several hundred milliseconds after the onset of stimulation and began to fade within a few seconds, despite continuing stimulation. The excitatory effects on relay neurons were blocked by scopolamine applied ionophoretically or intravenously, but not by noradrenergic antagonists, suggesting the cholinergic nature of LDT-induced excitation. During LDT stimulation the number of spikes evoked by photic stimulation of the receptive field of relay neurons usually increased, but it remained unchanged in a few cases. The increase was due to simple enhancement of photic responses or due to conversion of phasic type responses to tonic ones. As to the balance of background activity and photic responses, the effects of LDT stimulation varied from neuron to neuron. Even in a given neuron, the effects varied depending on its excitability level or the nature of the photic stimulation. These results show that the cholinergic projection from the LDT may be involved in the ascending reticular activating system, although the functional significance of the activating system in visual information processing in the geniculate nucleus remains to be clarified.

Acetylcholine↗
PubMed1986

Effects of lipophilic derivatives of L-ascorbic acid and dehydro-L-ascorbic acid on the peroxidation of linoleic acid in neutral phosphate buffer containing alcohol.

6-O-Palmitoyl-AsA (AP) and -DHA (DHAP) suppressed LA peroxidation considerably in both 10% and 20% EtOH solutions. The duration of the suppression of LA peroxidation was longer with AP than with DHAP. But after the initial suppression of LA peroxidation, both derivatives showed an accelerating effect. 6-O-Acetyl-AsA (Ac-AsA) and -DHA (Ac-DHA) accelerated LA peroxidation from the start of the reaction in 10% EtOH, but suppressed it notably in 20% EtOH. 4-Phenyl-2,3-dihydroxy-2-buten-4-olide (PDHB) and 4-phenyl-2,3-dioxo-4-butenolide (PDOB) accelerated LA peroxidation in 10% EtOH. With 20% EtOH solution, PDHB suppressed LA peroxidation notably, as did AP, but PDOB showed only a short duration (about 1 h) of suppression. These results suggest the complexity of LA peroxidation catalyzed by lipophilic AsA or DHA in aqueous solution containing alcohol.

4-Butyrolactone↗
PubMed1986

Oligonucleotide fingerprint analysis on Japanese encephalitis virus strains after passage histories.

Genetic variation in Japanese encephalitis (JE) virus strains after various passage histories was examined by oligonucleotide fingerprints of the 42S genome RNA. The results indicated that genome changes occurred during passages of new virus isolates through cell lines or mouse brains, especially at earlier passage level in order to adapt quickly to different hosts. However, the changes were not sufficient to explain strain differences observed among fingerprints of various isolates.

Animals↗
PubMed1986

[Laboratory and clinical studies of imipenem/cilastatin sodium in the pediatric field].

Laboratory and clinical studies on imipenem/cilastatin sodium were carried out and the obtained results were summarized below. The antibacterial activity of imipenem against clinical isolates of S. aureus, E. coli, K. pneumoniae, Salmonella sp., S. marcescens and P. aeruginosa was measured by the plate dilution method with an inoculum size of 10(6) cells/ml. The growth of S. aureus was inhibited at an imipenem concentration of 0.025 microgram/ml or lower. The susceptibility distribution of E. coli to imipenem ranged from 0.1 to 1.56 micrograms/ml, and the peak of the distribution was at 0.1 microgram/ml. The peak of the susceptibility distribution of K. pneumoniae was 0.2 microgram/ml, and those of S. marcescens and Salmonella ranged from 0.2 to 1.56 micrograms/ml and from 0.1 to 0.39 microgram/ml, respectively. The growth of P. aeruginosa was inhibited at a concentration of imipenem at 6.25 micrograms/ml. For a pharmacokinetic study, imipenem/cilastatin sodium was given to 1 patient in a single dose of 10 mg/kg or 20 mg/kg by drip infusion over 1 hour. With drip infusion of imipenem/cilastatin sodium, the peak plasma levels obtained with the two doses (10 and 20 mg/kg) were 20.6/26.4 micrograms/ml and 19.4/36.5 micrograms/ml, respectively on completion of the infusion. Clinical responses to imipenem/cilastatin sodium were excellent in 6 patients and fairly good in 1 patient, and the clinical effectiveness ratio was 85.7%. No side effect was observed except for elevations of GOT and GPT in 1 patient.

Bacteria↗
PubMed1986

[Clinical studies of cefixime in pediatric field].

Pharmacokinetic and clinical studies of cefixime (CFIX) in children were done and the following results were obtained. Serum and urinary concentrations of CFIX were determined in 6 children aged 5 to 14 years given single doses of 1.5 or 6.0 mg/kg. Mean serum concentrations peaked at 4 hours after the administration of either 1.5 or 6.0 mg/kg, and respective peak values were 0.71 and 4.46 micrograms/ml. Biological half-lives for the low and the high doses were 5.28 and 4.45 hours, respectively. The 12-hours urinary recovery ranged from 7.0 to 13.8% after administration of 1.5 mg/kg, and the 8-hours urinary recovery was 18.1% after administration of 6.0 mg/kg. Therapeutic responses were recorded as excellent or good in 43 (97.7%) of the children, comprising 13 with tonsillitis and 31 with scarlet fever. The microbiological effectiveness of CFIX on identified pathogens comprising 29 strains of S. pyogenes and 2 strains of S. aureus was satisfactory as evidence by a high eradication rate of 93.5%. No clinical side effects were observed. Abnormal laboratory findings were elevation of GOT and/or GPT in 4 patients and eosinophilia in 1 patient. In conclusion, CFIX was found to be efficacious and safe for the treatment of bacterial infections in children.

Acute Disease↗
PubMed1986

Endocardial excision versus encircling endocardial ventriculotomy. A comparison of effects on ventricular structure and function.

Although endocardial excision and encircling endocardial ventriculotomy are being performed in patients with extensive triple-vessel disease and compromised ventricular function, long-term effects of the operative intervention on structure and function of the left ventricle have not been determined. These procedures were performed in healthy dogs in three groups: control (ventriculotomy alone), endocardial excision, and encircling endocardial ventriculotomy (five dogs per group). Six weeks later, through a left thoracotomy, an arterial line, left atrial line, and Swan-Ganz catheter were inserted. Cardiac output measurements permitted calculation of left ventricular stroke work index, and gated nuclear ventriculograms permitted calculation of left ventricular volume indices. Myocardial performance (stroke work index/end-diastolic volume index relation), systolic elastance (systolic blood pressure/end-systolic volume index relation) and diastolic pressure-volume relationship (left atrial pressure/end-diastolic volume index relation) were determined from volume loading studies. In the endocardial excision group, the left atrial pressures were increased at similar end-diastolic volumes (p less than 0.05 by performance and systolic elastance were similar in the three groups. On completion of hemodynamic studies, the hearts were excised. Gross and light microscopic examination showed that the inner layer of myocardium was scarred in the area of intervention after both endocardial excision and encircling endocardial ventriculotomy. In neither group was there significant morphologic change elsewhere in the myocardium. Both endocardial excision and encircling endocardial ventriculotomy have little effect on long-term structure and function when performed in healthy canine hearts.

Animals↗
PubMed1986

[Left ventricular function in hypertrophic cardiomyopathy: a Tc-99m radionuclide angiographic study during exercise].

Hypertrophic cardiomyopathy (HCM) generally shows increased systolic function of the left ventricle at rest, although patients with HCM often have decreased exercise tolerance and develop dyspnea or chest pain. The present study was to investigate of left ventricular (LV) function during exercise in 26 patients with HCM using Tc-99m equilibrium angiocardiography, and to elucidate the mechanism of impaired functional reserve during exercise. Controls consisted of 11 normal volunteers and 12 patients with chest pain syndrome who had no abnormality on coronary arteriography or left ventriculography. In patients with HCM, LV ejection fraction decreased from 65 +/- 8 (mean +/- SD)% at rest to 59 +/- 18% at peak exercise, in contrast to an increase among controls (from 56 +/- 9% to 64 +/- 9%). As compared with resting values, cardiac output increased to 168 +/- 24% at peak exercise in HCM, but the increase was significantly less than that in controls (215 +/- 47%). Stroke volume decreased gradually to 83 +/- 16% during exercise in HCM, while it increased to 114 +/- 10% at an exercise level of half intensity, and it decreased slightly to 106 +/- 16% at peak exercise. LV end-systolic volume decreased among controls to 78 +/- 27% at peak exercise, but remained unchanged in HCM (118 +/- 58%). An increase in peak ejection rate at peak exercise was less in HCM than in controls (143 +/- 26% vs 170 +/- 42%). No significant differences were observed between the two groups concerning changes in indices of LV diastolic function including LV end-diastolic volume, peak filling rate or 1/3 filling rate during exercise. In the analysis of LV function curves, pulmonary arterial diastolic pressure increased to a greater extent in HCM than in controls (19 +/- 6 mmHg vs 11 +/- 6 mmHg); whereas, an increase in the stroke work index was less in HCM (80 +/- 26 g.m/m2/beat vs 121 +/- 21 g.m/m2/beat) at peak exercise. Thus, the LV function curve shifted downward and to the right in patients with HCM. The above findings indicate that LV functional reserve during exercise is impaired, especially as to systolic function in patients with HCM, while deterioration of diastolic function may be partly compromised by elevated filling pressure.

Cardiomyopathy, Hypertrophic↗
PubMed1985

Filamin inhibits actomyosin ATPase activity in platelet.

Filamin, an actin cross-linker protein, has been shown to exist in platelet. The role of this protein in the platelet has remained unclear. In this report, we show that filamin inhibits the actin-activated Mg2+ -ATPase activity of platelet myosin. The activation caused by platelet actin is inhibited by 50% at the molar ratio of filamin to actin of 1/50. Platelet tropomyosin, which we showed to enhance the ATPase activity, does not abolish the effect of filamin. The results support the view that filamin stabilizes the actin network in the resting platelet.

Actins↗
PubMed1985

Ultrastructural cytochemistry of carbohydrates in microfibrils associated with the amorphous elastin in the monkey aorta.

Two distinct ultrastructural components of elastic fibers can be identified--namely, the amorphous elastin and the microfibrils. We have examined the tunica adventitia of monkey aortas to demonstrate differential localization of carbohydrates in elastic fibers and collagen fibrils using Thiéry's periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining of thin sections for vicinal-glycol-containing complex carbohydrates, en bloc concanavalin A (Con A) staining specific for alpha-D-mannosyl and alpha-D-glucosyl groups, and en bloc wheat germ agglutinin (WGA) staining specific for N-acetyl-D-glucosamine, N-acetylneuraminic acid, and N-acetyl-D-galactosamine. The PA-TCH-SP method moderately stained microfibrils and weakly stained collagen fibrils, but did not stain the amorphous elastin. Both Con A and WGA staining methods strongly stained microfibrils and moderately stained collagen fibrils, whereas the amorphous elastin lacked staining. Thus PA-TCH-SP, Con A, and WGA staining methods allow differential ultrastructural localization of carbohydrates in elastic fibers and collagen fibrils in monkey aortic adventitia and demonstrate the presence of more carbohydrate components in microfibrils than in collagen fibrils, whereas amorphous elastin lacks carbohydrate staining.

Animals↗