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Biomedical subjects

K Tamura

Publications and source records attributed to K Tamura.

At least 919 records · Page 51Linked to original sources
PubMed1991

Genotypic and cytogenetic study of acute myelocytic leukemia and chronic myelocytic leukemia in blast crisis: specific delta rearrangement pattern does not involve J delta gene locus.

We have analysed the configuration of immunoassociated genes and the karyotypes of 30 patients with acute myelocytic leukemia (AML) and 10 with chronic myelocytic leukemia in blast crisis (CML-BC). In AML, the frequencies of T-cell receptor (TcR) beta, gamma, and delta chain and immunoglobulin heavy and light chain gene rearrangements were 4.2%, 19%, 8%, 10.7% and 10.5%, respectively. In CML-BC, they were 10%, 20%, 40%, 50% and 0%, respectively. Nine patients had abnormalities in chromosome 2, 7 or 14, upon which immunoassociated genes are located. There seems to be no apparent relationship between these chromosome abnormalities and gene rearrangements. In all patients but one (5/6), the delta rearrangement was accompanied by other immunoassociated gene rearrangements. Molecular size analysis revealed specific delta rearranged band(s) (19.5 kb-BamHI and/or 6.9 kb-EcoRI), as commonly detected in B-acute lymphocytic leukemia (ALL). All the patients with the delta rearranged band, however, had a germline configuration of J delta gene loci, suggesting a DD or V(D)D (probably V delta 2(D)D) pattern. This study also indicates that the delta rearrangement is specific in AML or CML-BC and distinct from that in early T leukemia/lymphoma.

Blast Crisis↗
PubMed1991

A patient of CD4-/CD8+ chronic T-cell leukemia associated with hypercalcemia.

A patient with chronic T-cell leukemia characterized by a suppressor phenotype is reported. A 71-year-old woman presented with symptoms and signs of hypercalcemia. Peripheral blood specimen showed abnormal lymphoid cells with an oval to cleaved nucleus, rather condensed chromatin, occasional prominent nucleolus, and basophilic cytoplasms with vacuoles which seems to be a T-cell counterpart of B-cell chronic lymphocytic leukemia with mixed cell types. The phenotype of these cells was CD4-, CD8+, CD5+, CD6+ with poor expression of CD3, CD7, and CD25. Southern blot analysis of T-cell receptor beta-chain gene revealed one allele rearranged band. The serum antibodies were positive against human T-cell leukemia virus, type I-associated antigens, but monoclonal integration of proviral DNA was not detected in the leukemic cells suggesting that she was just a carrier of this virus. Interestingly, serum PTH-related peptide (PRP) was elevated. The combination therapy with vincristine and prednisolone for leukemia decreased not only the number of leukemic cells but also the serum PRP levels. The clinical course was aggressive. She only responded transiently to treatments, and died of renal failure due to uncontrollable hypercalcemia six weeks after admission.

Aged↗
PubMed1991

Dipeptidyl aminopeptidase IV staining of cytologic preparations to distinguish benign from malignant thyroid diseases.

Staining for dipeptidyl aminopeptidase IV (DAP IV [EC: 3.4.14.5]) activity was applied to aspiration biopsy specimens or imprint preparations of surgical biopsy specimens from thyroid tumors. Material was obtained from 55 patients with histologically proven thyroid diseases: 9 with papillary carcinoma, 5 with follicular carcinoma, 11 with follicular adenoma, 13 with adenomatous goiter, 8 with Hashimoto's thyroiditis, and 9 with other benign conditions. Most tumor cells, follicular lumina in cell clusters, and intranuclear inclusions were strongly positive for DAP IV in all examples of papillary or follicular carcinoma. In contrast, only a few epithelial cells were labeled for DAP IV in follicular adenoma and adenomatous goiter. Some Hürthle cells in Hashimoto's thyroiditis also were positive for DAP IV. When a DAP IV scoring system based on the percentage of positive cells and staining intensity was used, all benign tissues except one (from a follicular adenoma) were found to have extremely low scores. These results indicate that staining for DAP IV activity is a simple but useful tool to aid in distinguishing benign from malignant thyroid neoplasms.

Adenocarcinoma↗
PubMed1991

Effect of left ventricular hypertrophy secondary to systemic hypertension on left coronary artery flow dynamics.

STUDY OBJECTIVE: The aim was to clarify the characteristics of the phasic blood velocity pattern and their possible causes in left ventricular hypertrophy secondary to systemic hypertension. DESIGN: Measurements of blood velocities in the left anterior descending coronary artery were made with a 20 MHz Doppler catheter with a top mounted annular crystal. All patients had normal coronary arteriograms. PATIENTS: 23 hypertensive patients [systolic/diastolic pressure: 181(SD 15)/100(4) mm Hg)] with left ventricular hypertrophy, and 13 atypical chest pain patients without left ventricular hypertrophy or any abnormal haemodynamic findings (normal controls) entered the study. MEASUREMENTS AND MAIN RESULTS: The left anterior descending coronary artery blood velocity waveform in pressure overloaded left ventricular hypertrophy was characterised by delayed early diastolic inflow. The diastolic rise time of coronary flow (TDR), ie, the time from the beginning of diastole to peak velocity, was higher in patients with hypertensive left ventricular hypertrophy than in normal controls, at 145(56) v 66(15) ms, p less than 0.001. In patients with hypertensive left ventricular hypertrophy, TDR correlated well with the degree of hypertrophy (r = 0.83, p less than 0.01) and also with peak left ventricular systolic pressure (r = 0.62, p less than 0.01). The coronary flow reserve, calculated from the ratio of the diastolic mean velocity after intracoronary injection of papaverine to the resting flow velocity, decreased with prolongation of TDR (r = 0.58, p less than 0.02). CONCLUSIONS: (1) Impairment of early diastolic coronary arterial inflow is the most remarkable characteristic in pressure overloaded left ventricular hypertrophy; (2) preceding systolic vascular compression and impaired left ventricular relaxation correlate with the delayed early diastolic inflow; (3) the delayed inflow is an important possible cause of the decreased coronary flow reserve in the hypertensive left ventricular hypertrophy.

Adult↗
PubMed1991

Protective effect of preconditioning on reperfusion induced ventricular arrhythmias of isolated rat hearts.

STUDY OBJECTIVE: The aim was to investigate the effect of preconditioning on reperfusion induced arrhythmias in the isolated working rat heart. DESIGN: Rat hearts were perfused with modified Krebs-Henseleit bicarbonate buffer. A 15 min period of global ischaemia was performed followed by a reperfusion period of 5 min. This procedure was repeated three times. Hearts were divided into the control group (n = 10) and the free radical scavenger group (n = 11). Hearts in the latter were reperfused in the presence of scavengers (SOD 3.5 x 10(4) U.litre-1 and catalase 5.0 x 10(5) U.litre-1). EXPERIMENTAL MATERIAL: Hearts were obtained from male Sprague-Dawley rats (270-350 g). MEASUREMENTS AND MAIN RESULTS: The incidence of reperfusion induced ventricular fibrillation in the control group decreased from 100% to 70% (NS) and to 40% (p less than 0.01) during the second and the third reperfusion periods, respectively. In the scavenger group, the incidence of ventricular fibrillation was the same in each reperfusion period at 45%. The time to onset of ventricular fibrillation increased at the second reperfusion in both groups. CONCLUSIONS: (1) The protective effect of preconditioning on reperfusion induced arrhythmia is evident in the isolated rat heart. (2) Addition of free radical scavengers reduced the incidence of reperfusion arrhythmia. However, the protective effect of preconditioning was lost.

Animals↗
PubMed1991

Mitochondrial DNA polymorphisms in the two subspecies of Drosophila sulfurigaster: relationship between geographic structure of population and nucleotide diversity.

Recent empirical and theoretical studies on mitochondrial DNA (mtDNA) variation in higher animals have suggested that the extent of mtDNA polymorphism is largely affected by spatial population subdivision. To examine this we studied mtDNA polymorphism in two subspecies of Drosophila sulfurigaster: D. s. albostrigata and D. s. bilimbata. Drosophila sulfurigaster albostrigata is mainly distributed on the mainland of Southeast Asia. In contrast, D. s. bilimbata forms discontinuous populations on many islands scattered in the Pacific Ocean. Because of the difference in their distribution patterns, the two subspecies are thought to be different in the extent of spatial population subdivision. mtDNA was isolated from greater than 50 isofemale strains for each subspecies and were analyzed by eight restriction endonucleases. Nucleotide diversity within a population was higher in D. s. albostrigata than in D. s. bilimbata. However, haplotype diversity was 1.6 times greater in D. s. bilimbata (0.85) than in D. s. albostrigata (0.53). The large difference in overall heterogeneity was attributed to the difference in interpopulational nucleotide diversity. For the two subspecies the proportion of interpopulational gene diversity in a subdivided population was calculated to be 0.54 in D. s. bilimbata and 0.40 in D. s. albostrigata. These observations indicate that spatial population subdivision is a major factor in determining mtDNA polymorphism in these subspecies. The extent of mtDNA divergence between the subspecies was very high. The average nucleotide divergence between them was 7.6%, which is almost the interspecific level reported for other Drosophila species. The cause of the high degree of mtDNA divergence is discussed.

Animals↗
PubMed1991

Rapid diagnosis of cytomegalovirus infections by direct immunoperoxidase staining with human monoclonal antibody against an immediate-early antigen.

Direct immunoperoxidase technique using a horseradish peroxidase (HRP)-conjugated Fab' fragment of human monoclonal antibody (humab C7), designated HRP-C7, was evaluated as a rapid diagnosis of cytomegalovirus (CMV) infection. A total of 138 clinical specimens consisting of 124 urine samples and 14 oral swabs were examined for CMV by the direct HRP-C7 staining in comparison with conventional virus isolation. The number of CMV-positive samples by each method was 40 (29.0%) for the former and 37 (26.8%) for the latter, respectively. By HRP-C7 staining, CMV was identifiable within 24 hr after inoculation. By conventional isolation method, an average of 10.3 days had passed before cytopathic effect characteristic of CMV appeared in the cell culture. Some false-positive and false-negative cases were discussed in relation to toxicity of urine samples, storage of the samples, and amount of CMV in the sample. The sensitivity and specificity of HRP-C7 method against conventional isolation method were 89.2% and 93.1%, respectively. Thus, HRP-C7 staining is useful for a rapid diagnosis of CMV infections.

Antibodies, Monoclonal↗
PubMed1991

[An outbreak of gastroenteritis possibly caused by Escherichia coli O167:H9].

An outbreak of gastroenteritis involving a total of 256 patients (49.7%) among 515 persons occurred at a primary and secondary school in Agatsuma Town, Gunma Prefecture between the 23rd and 28th of June 1988. The majority of the cases occurred within the first 4 days. The main symptoms were abdominal pain (81.6%), diarrhea (57.0%) and headache (40.2%). In most cases, the stools were watery and occasionally mucous. Although food-borne infection was strongly suggested epidemiological evidence did not incriminate any foods as the cause of the outbreak. In the bacteriological study on stool specimens from 25 patients, Escherichia coli O167:H9 was isolated from 20 of these specimens, virtually in pure culture. The isolates of the E. coli serovar were negative for recognized diarrheagenic virulence properties: production of heat-labile and heat-stable enterotoxins, enteroinvasion, and production of Shiga-like toxin. When the HEp-2 cell-adherence test was used, however, they exhibited localized adherence. All the strains were demonstrated to carry 56 Md plasmids that presumably mediate the production of the adherence factor.

Adolescent↗
PubMed1991

Pathogenic properties of Edwardsiella species.

The pathogenic characteristics of 35 Edwardsiella strains from clinical and environmental sources were investigated. Overall, most Edwardsiella tarda strains were invasive in HEp-2 cell monolayers, produced a cell-associated hemolysin and siderophores, and bound Congo red; many strains also expressed mannose-resistant hemagglutination against guinea pig erythrocytes. Edwardsiella hoshinae strains bound Congo red and were variable in their invasive and hemolytic capabilities while Edwardsiella ictaluri strains did not produce either factor; neither E. hoshinae nor E. ictaluri expressed mannose-resistant hemagglutination nor elaborated siderophores under the tested conditions. Selected strains of each species tested for mouse lethality indicated strain variability in pathogenic potential, with E. tarda strains being the most virulent; 50% lethal doses in individual strains did not correlate with plasmid content, chemotactic motility, serum resistance, or expression of selected enzyme activities. The results suggest some potential important differences in pathogenic properties that may help explain their environmental distribution and ability to cause disease in humans.

Animals↗
PubMed1991

Superimposition of poststreptococcal acute glomerulonephritis on the course of IgA nephropathy.

A 17-year-old male with poststreptococcal acute glomerulonephritis (PSAGN) superimposed on the course of IgA nephropathy is presented. The histological findings of the first renal biopsy showed mild IgA nephropathy with a mesangial deposition of IgA and C3. Eighteen months later, acute nephritic syndrome with hypocomplementemia and rising antihyaluronidase titer occurred 10 days following the onset of an upper respiratory infection. The second renal biopsy revealed severe diffuse endocapillary proliferative and exudative glomerulonephritis with cellular crescents in 70% of the glomeruli. Immunofluorescence showed granular staining of C3 alone along the capillary walls. The pre-existing IgA deposits had disappeared. Typical 'humps' were observed by electron microscopy. The symptoms were gradually resolved by intensive steroid and anticoagulant therapy. Five months after the episode of acute nephritic syndrome, the patient was clear of symptoms except for mild proteinuria and hematuria. The third renal biopsy at that time showed morphologic changes similar to those of the first renal biopsy with mild mesangial IgA deposits.

Adolescent↗
PubMed1991

Pneumoperitoneum in a patient with lymphangiomyomatosis.

A 32-year-old Japanese housewife with a 2-year history of retroperitoneal and pulmonary lymphangiomyomatosis had a sudden onset of severe abdominal pain. Chest X-ray and plain abdominal films showed free air under the diaphragm and a small pneumothorax in the left lower pleural space. Emergency laparotomy revealed no perforated viscera, but there was a rupture in the mid-portion of the left diaphragm. It appears that increasing pressure in the left pneumothorax burst the left diaphragm leading to pneumoperitoneum.

Adult↗
PubMed1991

Platelet volume, aggregation, and adenosine triphosphate release in cerebral thrombosis.

We compared whole blood platelet aggregation, adenosine triphosphate release, platelet count, platelet crit (percentage volume of platelets), and mean platelet volume during the acute, subacute, and chronic periods of cerebral thrombosis in 22 patients with value in 29 controls. During the acute and subacute periods, platelet aggregation, platelet count, platelet crit, and mean platelet volume were significantly less in the patients than in the controls (p less than 0.05-0.01) while the adenosine triphosphate release rate per volume of platelets was significantly greater (p less than 0.05). During the acute period, infarct size showed a significant positive correlation with platelet aggregation (r = 0.59, p less than 0.01) and adenosine triphosphate release rate (r = 0.70, p less than 0.001) but a negative correlation with platelet count (r = -0.44, p less than 0.05). Our results suggest that platelet aggregation is reduced during the acute period due to the consumption of platelets during thrombogenesis but that the remaining individual platelets are hyperactive. Platelet consumption during the acute period increases with infarct size. During the chronic period, platelet crit and mean platelet volume were significantly less in the patients than in the controls (p less than 0.01) while the adenosine triphosphate release rate was significantly greater (p less than 0.01), suggesting sustained platelet consumption and chronically enhanced secretion of individual platelets.

Adenosine Triphosphate↗
PubMed1991

The role of oxygen free radicals and extracellular calcium ions in reperfusion-induced arrhythmias.

To examine the role of oxygen free radicals and extracellular calcium ions in reperfusion-induced ventricular arrhythmias, we evaluated the effects of hypoxic reperfusion, oxygen free radical scavengers, allopurinol and hypocalcemic reperfusion on reperfusion-induced ventricular arrhythmias. The hearts of male Sprague-Dawley rats were perfused in the working heart mode. Whole heart ischemia was induced for 15 min and then reperfused. Rats were divided into 5 groups: control group, scavenger group, allopurinol group, hypoxia group and hypocalcemia group. Scavenger, hypoxic and hypocalcemic perfusions were undertaken only during the period of perfusion. The incidence of reperfusion-induced ventricular fibrillation (Vf) was reduced in the scavenger group (100% to 38%) and the hypoxia group (100% to 50%). Spontaneous reversion of Vf to regular sinus rhythm was recognized in the hypoxia and hypocalcemia groups. In conclusion, oxygen free radicals would play an important role in the genesis of the reperfusion arrhythmias, and extracellular calcium concentration would also play an important role in sustaining the reperfusion arrhythmias. Notably, hypoxic reperfusion had protective effects on both processes.

Allopurinol↗
PubMed1991

Oxygen dependence of lipid peroxidation in mice.

Peroxidation of lipids in serum and tissues of mice placed in low or high levels of oxygen was examined. After exposure to 100% oxygen for 3 h, no significant differences were observed between control and exposed mice. However, exposure to 100% oxygen for 6 h resulted in a decrease in oxygen consumption, an increase in lipid peroxides in tissues and serum, and the formation of hydroxyl radicals in tissues and serum. At low concentrations of oxygen (14% or 16%), a decrease in oxygen consumption, peroxidation of lipids and formation of hydroxyl radicals also were observed. Damage to mice was great with the lower oxygen concentrations of oxygen. There was a close correlation between the consumption of oxygen lipid peroxidation, formation of hydroxyl radicals.

Animals↗
PubMed1991

Murine model of leptomeningeal dissemination using human medulloblastoma cells.

An experimental model of meningeal dissemination was developed by intracisternal inoculation of human medulloblastoma (ONS-76) cells into nude mice. All mice died within 65 days after inoculation of 1 x 10(7) tumor cells. The median survival time was 56 days. Clinical signs and histological findings were similar to those in medulloblastoma patients with meningeal dissemination. Immunohistochemical studies showed that ONS-76 cells in the subarachnoid space expressed major histocompatibility complex (MHC) class I antigens until 20 days after inoculation. After 30 days, expression of MHC class I antigens decreased and cells began to proliferate rapidly. Expression of MHC class I antigens on tumor cells may result in effective recognition by the host immune system.

Animals↗
PubMed1991

Chronobiologic evaluation of drug efficacy in hypertension.

Time-associated variations of blood pressure became accessible due to the modern development of pressure monitoring technology. The data collection and analysis should be standardized and formulated. Time-associated changes of pressure were evaluated not only by nonparametric and conventional but also by parametric and rhythmometric estimation. The reference data (chronodesms) are essential to define the deviant magnitude of pressure. This chronobiologic approach became feasible to quantitate the efficacy of antihypertensive agents in hypertensives.

Antihypertensive Agents↗
PubMed1991

[Cases of advanced cholangiocarcinoma showing partial response by the combination chemotherapy including protracted continuous infusion of 5-FU combined with intravenous administration of low-dose leucovorin and intra-arterial administration of MMC and CQ].

We treated a patient with advanced cholangiocarcinoma with a new combination chemotherapy (modified MQF). The regimen consisted of intra-arterial administration of MMC (20 mg/body) and CQ (4 mg/body), protracted continuous infusion of 5-FU (500 mg/body) and intravenous administration of low-dose leucovorin (30 mg/body). More than 50% reduction in the liver tumor for over 4 weeks was obtained by the therapy. As for toxicity, diarrhea and stomatitis were observed.

Adenoma, Bile Duct↗