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Biomedical subjects

A Tamura

Publications and source records attributed to A Tamura.

At least 343 records · Page 19Linked to original sources
PubMed1991

Electron microscopic studies on the in vitro proliferation of spotted fever group rickettsia isolated in Japan.

Rickettsia was isolated from a patient with Japanese spotted fever, and its proliferation in cultured green monkey kidney cells was observed by electron microscopy. In the course of this study, we observed fusion of infected cells to uninfected cells which may be a way of spreading the rickettsiae from a cell to another. On the other hand, whirlpool-like, multilayer membranous structures, similar to the mesosomes of gram-negative bacteria, were sometimes seen in the rickettsial cells. The other profiles common to the other rickettsiae in spotted fever group were observed, such as the electron-lucent halo zone around the rickettsiae, and external fibrous materials on their surface, but intranuclear multiplication was rarely observed.

Cell Division↗
PubMed1991

Specific amplification of Rickettsia tsutsugamushi DNA from clinical specimens by polymerase chain reaction.

Polymerase chain reaction (PCR) was used to detect Rickettsia tsutsugamushi-specific DNA in clinical specimens. The primer pair used for PCR was designed from the nucleotide sequence of the gene encoding the 56-kDa antigen of the Gilliam strain. Theses primers led to a 78-bp fragment by amplifying the genomic DNAs from five serovariants, i.e., the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of R. tsutsugamushi, and also the DNA from blood clots of patients with scrub typhus, even at the early stage of onset of the disease. This indicates that this method is suitable for the diagnosis of scrub typhus.

Base Sequence↗
PubMed1991

Use of monoclonal antibodies against Rickettsia tsutsugamushi Kawasaki for serodiagnosis by enzyme-linked immunosorbent assay.

Monoclonal antibodies (MAbs) against Rickettsia tsutsugamushi Kawasaki were prepared. The crossreactivity tests of the MAbs performed by using antigenically distinct strains of R. tsutsugamushi in immunofluorescence and immunoblotting analyses indicated that the Kawasaki strain contains a strain-specific epitope and also contains a common epitope on the 56-kDa polypeptide cross-reactive with the Gilliam strain, group- and subgroup-specific epitopes on the 46-kDa polypeptide, and a subgroup-specific epitope on the 25-kDa polypeptide. By using the strain-specific MAb for serodiagnosis of tsutsugamushi disease (or scrub typhus fever), we have established a method which was designated the inhibition enzyme-linked immunosorbent assay. The principle of the method is to measure the percentage of inhibition of antigen absorption on a MAb-coated plate by antibody-positive sample sera which were mixed with the antigen suspension. The advantages of this test for practical use are that (i) crude antigen can be used, i.e., purification of the antigen is not required; (ii) the test is more sensitive than immunofluorescence; (iii) the final judgment of plus or minus is clear-cut; and (iv) rickettsial antigenic types in the patients can be distinguished by this test.

Antibodies, Bacterial↗
PubMed1991

Electrocardiographic findings in a patient with pure septal infarction.

The electrocardiogram in a 65 year old man in whom pure septal infarction had been produced by occlusion of the septal branch during percutaneous transluminal coronary angioplasty showed that this had led to the disappearance of septal Q waves and reciprocal ST segment depression in the inferior leads.

Aged↗
PubMed1991

Long-term low-dose administration of erythromycin to patients with diffuse panbronchiolitis.

Although diffuse panbronchiolitis (DPB) has carried a poor prognosis, long-term low-dose administration of erythromycin (EM) is very effective. We administered EM at a daily dose of 400-600 mg to 19 DPB subjects for more than 2 months. Sixteen subjects were relieved from productive cough and dyspnea, and their chest X-ray pictures were improved. We performed a pharmacokinetic study of EM in 11 DPB subjects (8 responders; 3 nonresponders) after the long-term low-dose administration. The maximal serum and sputum levels of EM were below the MICs of clinically pathogenic H. influenzae and P. aeruginosa which were often isolated from the sputum of DPB patients. No difference was observed in the absorption of EM between responders and nonresponders. The results suggested that DPB patients might respond favorably to EM due to mechanisms other than antibacterial activity. Individual variation in the absorption of EM was observed. As EM was effective at very low serum and sputum levels, it was suggested that even 200 mg/day of EM would be effective in DPB patients who had high serum and sputum EM levels and it was necessary to monitor the concentrations of EM in serum and sputum for the treatment of DPB to determine the appropriate dose of EM individually.

Adult↗
PubMed1991

Lithium ion does not protect brain against transient ischemia in gerbils.

It has been proposed that lithium ion desensitizes neuronal receptors that function via the inositol phospholipid signaling mechanism. We examined the effects of lithium chloride on the morphologic outcome after 5 minutes of cerebral ischemia induced in gerbils by occluding both common carotid arteries under brief halothane anesthesia. In three treated groups of 10 gerbils each, 5 meq/kg i.p. lithium chloride was given 2 days, 1 day, and 2 hours before ischemia; 2 hours before ischemia; or immediately after the end of ischemia. Corresponding control groups of nine or 10 gerbils each received equivalent volumes of saline injected at comparable times. All gerbils were perfusion-fixed 1 week later, and neuronal density of the hippocampal CA1 pyramidal cells was determined. Lithium induced very mild intraischemic systemic hypothermia, but postischemic hyperthermia developed in both treated and control groups. Neuronal densities were equal in corresponding groups. The results indicate that our regimen of lithium administration provides no benefit in survival of hippocampal neurons, and intraischemic hypothermia of less than 0.8 degrees C is not protective. Other strategies to inactivate the signal transduction system that is specific for excitatory neurotransmission should be evaluated.

Animals↗
PubMed1991

Thalamic atrophy following cerebral infarction in the territory of the middle cerebral artery.

We investigated shrinkage of the ipsilateral thalamus following infarction in the territory of the middle cerebral artery in 33 patients who were admitted less than or equal to 2 days after the stroke and who were followed by computed tomography for greater than 1 year with no recurrences. The thalamic area was measured on the computed tomograms, and the ratio of the ipsilateral area to the contralateral area was calculated. All values were compared with values from the initial computed tomogram taken less than or equal to 2 days after the stroke. The values of the ratio on follow-up computed tomograms decreased gradually in 15 patients. In these cases, the area of the ipsilateral thalamus was significantly reduced after 1 year (p less than 0.01) and marked atrophy was observed. These results demonstrate the significance of remote changes over a long period of time after focal cerebral infarction.

Atrophy↗
PubMed1991

Synthesis and oral activity of pivaloyloxymethyl 7-[(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3(Z)- (4-methylthiazol-5-yl)vinyl-3-cephem-4-carboxylate (ME1207) and its related compound.

7-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3(Z)- (4-methylthiazol-5-yl)vinyl-3-cephem-4-carboxylic acid (11, ME1206) and its 3-trans isomer (13) were prepared to test antibacterial activity. These compounds exhibited excellent antibacterial activity against both gram-positive and gram-negative bacteria, including beta-lactamase producing strains. The pivaloyloxymethyl esters (12 and 14) of the compounds (11 and 13) were prepared by esterification with pivaloyloxymethyl iodide. Among them, pivaloyloxymethyl 7-[(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]- 3(Z)-(4-methylthiazol-5-yl)vinyl-3-cephem-4-carboxylate (12, ME1207) showed good urinary recovery after oral administration in mice.

Administration, Oral↗
PubMed1991

A case of clinically diagnosed pure septal infarction.

Interventricular septal involvement in myocardial infarction is usually associated with infarction of the left ventricular anterior free wall, as the obstruction is at the major portion of the left anterior descending coronary artery. Acute myocardial infarction with obstruction only of the first septal branch is rare. We describe here a case of pure septal infarction. The case was diagnosed by emergency coronary arteriogram (CAG). Although the patient had a large first septal branch, his global left ventricular function was preserved. Abnormal findings were localized in only septal region as determined by left ventriculography (LVG), two-dimensional echocardiography (2DE), and 99mtechnetium pyrophosphate (99m Tc-PYP) and 201thallium (201Tl) myocardial scintigraphy.

Adult↗
PubMed1991

[Immunohistochemical findings in resected lung cancer].

The relationship between histological type and immunohistological findings was studied in total 141 cases of resected lung cancer. Adenocarcinoma was cytologically subtyped according to the ultrastructural findings. Immunohistochemical staining was performed on paraffin-embedding tissue using the avidin-biotin-peroxidase complex method for carcinoembryonic antigen (CEA), keratin, secretory component (SC), neuron specific enolase (NSE), lysozyme (Ly) and lactoferrin (La). Adenocarcinoma stained strongly positive with antibody against CEA and SC. There was no statistical difference among the different subtypes of adenocarcinoma, but in the cases of clara cell type, CEA staining was less intense and in goblet cell type, the intensity of SC staining was great. Goblet cell type characteristically stained positively with anti-Ly antibody, and Ly was a specific marker for differentiating adenocarcinoma of goblet cell type. La was positive not only in bronchial gland cell type, but also in other subtypes in adenocarcinoma. Squamous cell carcinoma showed more intense staining with anti-keratin antibody than other histological types. Small cell carcinoma extensively stained with anti-NSE antibody, but some of the other histological types also stained positively. NSE was a relatively good marker for small cell carcinoma but was not specific. It is concluded that immunohistochemical examination is a useful method for differentiation of different histological types of lung cancer.

Adenocarcinoma↗
PubMed1991

In vitro and in vivo antibacterial activities of ME1220 and ME1221, novel cephalosporins.

The antibacterial activities and serum pharmacokinetic properties of ME1220 and ME1221, new aminothiazolylalkoxyiminoacetylcephalosporins having an N-alkylpyridiniumthiomethyl side chain at C-3, were compared with those of cefpirome and ceftazidime. ME1220 and ME1221 exhibited broad antibacterial activity against Gram-positive and Gram-negative bacteria. The in vitro and in vivo activities of ME1220 were similar to cefpirome, while ME1221 was superior to ceftazidime against almost all test organisms except pseudomonas. On intravenous injection in rats, ME1220 and ME1221 were excreted mainly in the urine. ME1221 was excreted moderately in the bile and showed higher serum concentration and AUC than those of ME1220.

Animals↗
PubMed1991

[Temporal profile of the superoxide dismutase and the ascorbic acid in focal cerebral ischemia].

It has been proposed that free radical reactions are involved in ischemic brain damage. Since irreversible pathological changes occurs very early phase of the focal ischemia and the ischemic brain edema reaches its peak at about 2 days of ischemia, the free radical reactions must take place before these changes. Superoxide dismutase is a famous enzyme that dismutase superoxide anion, which is believed to be one of the initiator of the free radical reactions. If superoxide anion plays a pivotal role in the genesis of pathological ischemic brain damage and edema, the activity of the enzyme may decrease in the early phase of ischemia. Ascorbic acid is also known to be a scavenger of superoxide anion, and brain tissue contains it in a high concentration. We investigated the changes in superoxide dismutase activity and concentration of reduced ascorbate in focal ischemia. Focal ischemia was produced in rats by permanent occlusion of the left middle cerebral artery. The animals were decapitated 30 minutes, 4, 24, and 48 hours after the operation. Middle cerebral artery territory of each cerebral hemisphere was homogenized and centrifuged with phosphate buffer. The supernatant was divided into two aliquots; one was dialyzed to remove ascorbate and the other was not. The SOD activity was measured by electron-spin-resonance (ESR) spin trapping method, and the ascorbic acid concentration was measured by high performance liquid chromatography with electrochemical detection (HPLC-ECD). Protein concentration was measured by Lowry's method. The enzyme activity was expressed as unit/mg protein, and the ascorbic acid concentration was expressed as microgram/g tissue. The SOD activity decreased markedly by dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Electrocardiographic observations of pure septal infarction: a case report].

We report a very rare case of pure septal infarction, which was closely examined with detailed electrocardiography (ECG). The patient is a 65-year-old man, who underwent percutaneous transluminal coronary angioplasty (PTCA) for exercise-induced angina. During PTCA for the target lesions in the left anterior descending artery (LAD) and diagonal branch, a large septal branch originating from the LAD was accidentally and completely occluded. Septal Q waves then disappeared from leads I, V5 and V6, and ST segments were elevated in leads V1 to V3, with concomitant ST depressions in leads I, II, aVF, V5 and V6. It was speculated that the initial electrical potential derived from the central septum may have been lost due to septal infarction, resulting in the disappearance of the septal Q waves. The present case disclosed the role of the interventricular septum in the genesis of septal Q waves in the left precordial leads.

Aged↗
PubMed1991

[Right ventricular infarction/ischemia with precordial ST elevation: comparison with left ventricular anterior wall infarction].

Acute right ventricular (RV) infarction is sometimes accompanied by precordial ST elevation which is also suggestive of left ventricular (LV) anterior wall infarction. We compared 12-lead electrocardiograms between 2 groups of patients with initial acute myocardial infarction presenting precordial ST elevation, one with RV infarction (n = 11) and the other with LV anterior wall infarction (n = 42). The magnitude and extent of the ST elevation and the positions presenting the maximal ST elevation in the precordial leads differed between the 2 groups. In the inferior and lateral leads, the analysis of the ST segment shift aided in distinguishing between the 2 groups. The specific patterns of intraventricular conduction delay and frontal QRS-axis deviation were also useful for the differentiation. The best electrocardiographic variable for identifying RV infarction was inferior lead ST elevation, followed by maximal precordial ST elevation in lead V1, ST elevation limited to only one precordial lead and a cove-shaped pattern of RV conduction delay. The best electrocardiographic predictor for diagnosing LV anterior wall infarction was an isoelectric or depressed ST-segment in the inferior leads, followed by precordial ST elevation equal to or greater than 5 mm, maximal ST elevation in lead V3 or V4 and ST elevation in the lateral leads. We concluded that systematic analysis of the 12-lead electrocardiograms recorded in the hyperacute stage is valuable for distinguishing between acute RV infarction and LV anterior wall infarction.

Aged↗
PubMed1991

[Multiple discriminant analysis for prognosis of refractory anemia].

Forty-eight patients with refractory anemia (RA) were retrospectively analyzed for their prognosis and subclassified into three groups: 12 patients with hematological improvement (A), 23 patients with no changes (B), and 13 patients with progression to RAEB or acute leukemia (C). For all patients, the median survival were 49.2 months, and the rate of leukemic transformation was 16%. The median survivals were 60.6, 32.1, and 17.9 months, respectively, for groups A, B and C. The factors indicating poor prognosis were low reticulocyte counts, low neutrophil alkaline phosphatase activity, low% red cell utilization, high M/E ratio, high blast percentage in the bone marrow and cytological abnormalities in the granulocyte and megakaryocyte series. By using multiple discriminant analysis, we obtained a formula for the prognostic estimation with a discrimination probability of 62.5%. This formula could predict either the patients with good (Y greater than 0.85) or poor (Y less than 0.59) prognosis, and might be useful to select the treatment for this intractable anemia at the time of diagnosis.

Adolescent↗
PubMed1990

Suppressive effect of E-64c on ischemic degradation of cerebral proteins following occlusion of the middle cerebral artery in rats.

Microtubule-associated protein 2 (MAP2) levels in the left cerebral hemisphere decreased significantly 3 days after occlusion of the left middle cerebral artery in rats to 29 +/- 16.3% of control levels. Since MAP2 is one of the substrates of calpain, E-64c, a synthetic calpain inhibitor, was administered at a dose of 400 mg/kg twice a day for 3 days, with the first dose being given before the production of ischemia. This depletion was significantly inhibited in vivo by E-64c (P less than 0.05) to increase MAP2 levels to 55 +/- 25.7% of control levels. E-64c had no significant effect on the ischemia-induced depletion of myelin-associated glycoprotein. Sham-operated rats were used as controls. Our results suggest that calpain is partially involved in the degradation of MAP2, and that the use of calpain inhibitors can be a useful clinical approach to cerebral ischemia.

Animals↗