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Biomedical subjects

T Kura

Publications and source records attributed to T Kura.

17 recordsLinked to original sources
PubMed2001

Relationship of third molar development and root angulation.

Angled roots are seen in mandibular third molars, which have a high frequency of incomplete impaction. We examined the relationship between incomplete impaction and angled roots. We enrolled orthopantomographs to determine the prevalence of angled roots in 239 men and 222 women aged 21--35 years with bilateral mandibular third molars. Angled roots were more frequent in subjects in whom the third molars had a different status on each side than in those with the same status on both sides (men: P<0.05; women: P<0.01). The incidence of women with angled roots in those with bilateral incomplete impactions was higher than that in those with bilateral eruption (P<0.01). Angled roots among mandibular third molars are related to environmental factors. Angled roots occur more frequently in women with incomplete impaction than in those with full eruption.

Adult↗
PubMed2000

Conditions for the evolution of soldier sperm classes.

There has been wide disagreement as to whether sperm competition among animals can produce a soldier class of sperm to fight against other males. Utilizing mathematical models, we analyze the appropriate conditions for the evolution and maintenance of a soldier sperm class. We conclude that: (1) soldier sperm evolve even if one soldier sperm can kill or block less than one competing sperm; (2) soldier sperm evolve faster when there is a large variance in the number of competing sperm; (3) soldier ratio increases until reproductive sperm are too scarce to fertilize all ova or a sperm intensely refuses to become a soldier; and (4) soldier sperm are more likely to be smaller than reproductive sperm. Our models suggest that the conditions for the evolution of a soldier sperm class are not stringent.

Animals↗
PubMed2000

A case of diffuse large B-cell lymphoma transformed from immunoglobulin A-producing marginal zone B-cell lymphoma.

We present a rare case of diffuse large B-cell lymphoma transformed from immunoglobulin (Ig) A-secreting marginal zone B-cell lymphoma. A 62-year-old woman was admitted to our hospital for examination of a disseminated pulmonary shadow. Gradual swelling of bilateral axilla and right inguinal lymph nodes were noted after admission. Histological examination of the lymph node biopsy specimen revealed the appearance of marginal zone B-cell lymphoma. The surface Ig of lymphoma cells was IgA-kappa, which coincided with the class of monoclonal Ig found in the patient's serum. The lymph node swelling and pulmonary shadow subsided, and the serum IgA level was normalized by 3 courses of systemic chemotherapy. However, after 4 courses of treatment, new tumor lesions at the right chest wall and left arm progressively became apparent. The biopsy specimen of the tumor showed a feature of diffuse large B-cell lymphoma. Despite intensive chemotherapy, the patient died of spreading tumor burden into the central nervous system.

Cell Transformation, Neoplastic↗
PubMed1999

Dilemma of the equality: an all-pay contest with individual differences in resource holding potential

An all-pay contest in which many players compete for an indivisible resource and each player continuously maintains a different resource holding potential (RHP) is analysed. There exists the unique pure ESS function, which is common sense; that is, a higher RHP induces a higher level of investment, and, as a consequence, a player with a greater RHP always wins. As the variance in distribution of RHP converges to zero, the ESS becomes equal to the symmetric mixed Nash-equilibrium reported by Rose, which does not satisfy the condition of ESS. This suggests that some unstable symmetric Nash equilibria change to ESS functions in some games when we extend the games by assuming one more random continuous parameter of the player's condition. Moreover, the smaller the individual differences in RHP, the more intense the competition becomes, and the smaller becomes the expected payoff for almost all individuals as well as the average payoff of the population. This negative correlation between equality in RHP and the payoff in the population was first found by Kura & Kura in a war-of-attrition game and named the "dilemma of equality". Its biological implications are also discussed. Copyright 1999 Academic Press.

Journal Article↗
PubMed1998

War of Attrition with Individual Differences on RHP.

The fact that there always exists various kinds of almost continuous mutations for any animal population implies that players in competitions can never be perfectly symmetric in any sense. To develop a model to fit this reality, we consider war of attrition games in which players have continuously different resource holding potential (RHP). The RHP of each opponent is not known in our settings. Pure ESS functions and Nash equilibria are obtained under sufficiently rotational conditions as unique solutions of certain differential equations among the class of Lebesgue measurable functions. They are normal in that a higher RHP induces a longer attrition time, which implies that a player with greater RHP always wins. This model includes as the limit the conclusions of Maynard Smith (1974, J. theor. Biol. 47, 209-221) and Norman et al. (1977, J. theor. Biol. 65, 571-578), which did not consider individual differences in RHP. Our results suggest that, by changing each player's qualitative differences to continuous quantitative differences, some of the mixed ESS solutions previously found in discrete games may degenerate into pure ESS functions. Moreover, we found that the smaller the individual differences of RHP, the smaller is the mean pay-off of most individuals as well as the total pay-off of the population.Copyright 1998 Academic Press

Journal Article↗
PubMed1998

Retroperitoneal extrarenal angiomyolipoma with early gastric carcinoma.

We present a very rare case of a retroperitoneal extrarenal angiomyolipoma accompanied by early gastric cancer. A 41-year-old Japanese man, who had undergone surgery for a type IIc early gastric cancer 2 years earlier, was admitted to hospital presenting with back pain and abdominal fullness. Computed tomographic scanning and magnetic resonance imaging of the abdomen disclosed a massive fatty tumor extending from the hepatic hilus to the retroperitoneum. A large retroperitoneal tumor mass with no sign of involvement in the kidney was totally resected by radical surgery. Histologically, the tumor was classified as an angiomyolipoma.

Adenocarcinoma↗
PubMed1997

[Hemolytic anemia and thrombocytopenia induced by cimetidine: recurrence with ranitidine administration].

A 69-year-old woman was admitted with apoplexy after operation of mitral valve stenosis and gastrectomy due to a gastric ulcer. In June 1994, her condition gradually worsened after acute pneumoniae in her right lung. Intravenous hyperalimentation with cimetidine administration was started to improve her undernourishment, because she had a history of gastric ulcer. However, after 10 days from the start of cimetidine therapy, anemia progressed rapidly. Biochemical examinations revealed that the serum indirect bilirubin and LDH levels were elevated and no serum haptoglobin was detected. These results indicated the development of hemolytic anemia, but at that time we could not clarify the reason. In October 1994, thrombocytopenia gradually progressed, and we halted the administration of cimetidine to ranitidine. Both hemolytic anemia and thrombocytopenia was dramatically improved after cessation of cimetidine administration. We then changed the drug from cimetidine, however the same phenomena have appeared again. The patient was in stable condition, after cessation of H2-blockers administration. The complication of hemolytic anemia and thrombocytopenia associated with H2-blocker administration in Japan.

Aged↗
PubMed1997

[Thrombocytopenia associated with sodium polystyrene sulfonate].

A 84-year-old man was admitted with diabetes mellitus, hypertension and chronic renal failure in September 1994. In October 1995, his renal function gradually worsened with hyperkalemia. Sodium polystyrene sulfonate (Kayexalate) was administered orally for the treatment of hyperkalemia. However, after 7 days from the start of Kayexalate therapy, thrombocytopenia progressed gradually, and 12 days later the initial platelet count of 20.7 x 10(4)/microliter decreased to 8.6 x 10(4)/microliter. This thrombocytopenia rapidly improved after cessation of Kayexalate administration. In December 1995, readministration of Kayexalate for the treatment of hyperkalemia induced thrombocytopenia again. Bone marrow aspiration biopsy revealed normal counts of nucleated cells and megakaryocytes with no increase in blasts. No other disorders which cause thrombocytopenia were seen in this patient. The complication of thrombocytopenia associated with Kayexalate has not been reported. This is the first reported case of thrombocytopenia caused by Kayexalate administration.

Aged↗
PubMed1996

Transfection of glutathione S-transferase (GST)-pi antisense complementary DNA increases the sensitivity of a colon cancer cell line to adriamycin, cisplatin, melphalan, and etoposide.

The goal of this study was to demonstrate that glutathione S-transferase (GST)-pi is directly involved in the intrinsic and acquired resistance of cancer cells to anticancer drugs. To this end, GST-pi antisense cDNA was transfected into the cultured human colon cancer cell line M7609, which expresses an innately high level of GST-pi and shows intrinsic drug resistance, and into an M7609 strain with acquired resistance to Adriamycin (ADR;i.e., M7609/ADR cells). The changes in the sensitivity of these transfectants to various anticancer drugs were investigated. The intracellular concentrations of GST-pi in M7609/anti-1 cells and M7609/anti-2 cells, two clones that were established by transfection of GST-pi antisense cDNA into M7609 cells, were decreased to approximately half of those detected in the parent cells (M7609) and in the control cells transfected with vector alone (M7609/pLJ). The sensitivities of the antisense transfectants in relation to ADR, cisplatin, melphalan, and etoposide were increased -3.3-fold, 2.3-fold, 2.2-fold, and 2.1-fold, respectively, compared with those of M7609 and M7609/pLJ. On the other hand, the sensitivities of the antisense transfectants to Taxol, vincristine, 5-fluorouracil, and mitomycin C were not significantly changed. Similarly, the transfection of antisense cDNA into M7609/ADR cells resulted in the reduction of intracellular GST-pi concentration (by about half) and an increased sensitivity to ADR (4.4-fold), but no increase in 5-fluorouracil sensitivity. Thus, GST-pi is considered to be a multidrug resistance factor that is responsible for both the intrinsic and acquired resistance of cancer cells to anticancer drugs such as ADR, cisplatin, melphalan, and etoposide.

Antineoplastic Agents↗
PubMed1996

Glutathione S-transferase-pi is secreted as a monomer into human plasma by platelets and tumor cells.

By employing an ELISA for detection of glutathione S-transferase-pi (GST-pi) established in our laboratory, gel filtration profiles of GST-pi in the plasma of normal subjects and patients with malignant tumors were investigated. The results showed that the plasma GST-pi for both of these groups was approximately half the molecular size of placental GST-pi used as a standard control. Similar analyses were performed on GST-pi of platelets and cultured cancer cells, which are considered to be the main sources of the GST-pi in the plasma of normal subjects and cancer patients, respectively. The results indicated that the GST-pi in both the centrifuged supernatants of aggregated platelets and in the culture medium of cancer cells was about half of the molecular size on intact GST-pi. Moreover, the GST-pi in the culture medium was shown to have an N-terminus and a C-terminus, by analysis with specific ELISA. Western blot analysis of the GST-pi in the culture medium detected a single band migrating at 23 kDa, confirming that the extracellular GST-pi was the monomer, not a cleaved form of intact GST-pi. The release of GST-pi from cancer cells was suppressed at 4 degrees C, or by sodium azide, but not suppressed by colchicine or cytochalasin B. These findings suggest that GST-pi may be released by an energy-dependent, active process, and not by a secretion mechanism.

Blood Platelets↗
PubMed1996

[Investigation of gastric cancers detected at a medical check-up center].

Most of the gastric cancers investigated in this study were detected during mass screening at a Medical Check-up Center. The research period was 5 years, from 1990 to 1994. The total number of patients undergoing initial gastric examinations was 300,658. Four point eight percent of these needed detailed examinations, and 77.2% actually underwent detailed examinations. Over the 5 years, the number of gastric cancers detected was 253. The rate of detection of these cancers was almost unchanged every year, with the average rate of change being 0.11%. The rate of detected gastric cancers was investigated according to age and sex. No cancers were found below age 29, and the rate gradually rose over age 30. Over age 50, the rate in males was twice that in females. The rate of early gastric cancers was 66.4% of all reported cancers. As regards location of 253 cases, 16.5% were in the C-area, 45.8% in the M-area, 36.2% in the A-area; 19.2% were in the greater curvature, 33.9% were in the lesser curvature, 17.3% in the anterior wall, and 26.1% in the posterior wall. The sizes of the lesions were as follows: 11.5% were below 1.0 cm, 29.6% were from 1.1 cm to 2.0 cm, 46.6% were from 2.1 cm to 5.0 cm, and 12.3% were over 5.1 cm. It was considered that indirect X-rays were slightly inferior to direct X-rays in detecting early gastric cancer. The X-ray positionings in which cancers were detected were: 75.7% by supine double contrast and 48.6% by compression in 144 cases of early cancer. On the other hand, the rate were 75.6% by supine double contrast, and 51.2% by compression in 82 cases of advanced cancer. A similar tendency was found in one-shot X-ray positioning which revealed cancers. The rate of gastric cancer notdetected by X-ray pictures was 5.9% of the 253 cases. The size of the cancers notdetected by X-ray was within 2.0 cm in all cases. 58.7% of the 155 early cancer patients and 48.2% of the 83 advanced cancer patients had examinations the previous year. Therefore, it is clear that some cases of advanced cancer were not detected in the mass gastric screenings. Endoscopically, 7 cases of gastric cancer were diagnosed correctly by means of repeated biopsies which were needed 3 or 4 times over 3 to 18 months owing to pseudonegative findings on the first bioptic examination. Consequently, it is necessary to make naked eye diagnosis by endoscopic examination. Six cases of death from gastric cancer were certified within one year after normal diagnosis during the mass screening. Three cases were Borr. 4, 2 cases Borr. 3, and 1 case was Borr 2. A retrospective investigation of X-ray pictures showed that it would have been difficult to identify the lesions in these cases. The above results show that the accuracy of examinations and diagnosis must be raised in mass gastric screenings, but it is doubtful whether relying on the present methods of screening will lead to a marked improvement. For the purpose of increasing the effectiveness of mass gastric screening, we would emphasize the necessity of the following new tests; serum pepsinogen measurement, reinvestigation of patient's ages, shortening the intervals between examinations in high risk groups, using direct X-rays rather than indirect X-rays, and intermitted endoscopic examinations.

Adult↗
PubMed1993

[Successful treatment with combination chemotherapy of BHAC-AMP in a case of acute myelofibrosis developed from myelodysplastic syndrome with multiple chromosomal aberrations].

A 62 year old male patient was previously admitted to another hospital in February 1989 because of palpitation. Peripheral blood examination revealed pancytopenia. Although the number of nucleated cells in the bone marrow aspirate was in the normal range. It contained 2.2% of blastic cells and dysplastic cells. He was diagnosed to be myelodysplastic syndrome with refractory anemia. He subsequently received repeated blood transfusions and other symptomatic treatments as an outpatient until 1990. When he was admitted to our hospital because of severe pancytopenia. The numbers of WBC, RBC, and platelets were 2,000/microliters, 134 x 10(4)/microliters, 2.9 x 10(4)/microliters respectively. Bone marrow aspiration resulted in dry tap, and biopsy at the iliac bone showed remarkable fibrosis with marked decrease of normal hematopoietic cells. Chromosome analysis revealed multiple aberrations such as 47XY, +8, 13q-, 14p+, 48XY, +8, +9, 13q+. The patient was treated with BHAC-AMP combination chemotherapy. After 3 cycles of the therapy, pancytopenia was improved and chromosomal aberration disappeared. This case was considered to be an acute myelofibrosis developed from myelodysplastic syndrome and worth to reporting with a review of literature, because drastic combination chemotherapy was extremely effective.

Aclarubicin↗
PubMed1992

[Primary carcinoma in diverticulum of the bladder: a report of three cases].

The first case was in a 48-year-old man admitted with a chief complaint of macroscopic hematuria and sense of residual urine. A tumor in the diverticulum of the bladder was detected by cystoscopy, computed tomography (CT) and magnetic resonance imaging (MRI). We made the diagnosis of an invasive tumor in the diverticulum of the bladder. Total cystourethrectomy and ileal conduit diversion was performed. Histopathological finding was transitional cell carcinoma including squamous cell carcinoma. Adjuvant chemotherapy was performed. No recurrence and metastasis has been recognized for 12 months. The second case was a 56-year-old man having an intradiverticular tumor diagnosed by cystoscopy, CT, and MRI. Total cystectomy and ileal conduit diversion was performed. Histopathological findings was squamous cell carcinoma. No recurrence has been recognized for 8 months. The last case was an 81-year-old man. The patient had the complication of a primary progressive squamous cell carcinoma of the skin. Transurethral resection of diverticular tumor was performed under the diagnosis of superficial tumor. Histopathological findings revealed transitional cell carcinoma. One hundred and sixty one cases of tumor in the diverticulum of the bladder were reviewed. Importance of aggressive treatment including total cystectomy was emphasized.

Aged↗
PubMed1991

Cytomegalovirus DNA in the sera of patients with cytomegalovirus pneumonia.

We attempted to detect cytomegalovirus DNA (CMV-DNA) in the sera of four leukaemia patients who underwent an allogeneic bone marrow transplant (BMT), in six leukaemia patients who suffered from pneumonia and in 16 healthy subjects, using the polymerase chain reaction (PCR). Three of the four BMT patients subsequently developed CMV pneumonia. In two cases, CMV-DNA was detected in the sera at about the time the pneumonia occurred, and the amount of DNA increased with disease progression. The serum of the third patient became positive for CMV-DNA before he developed pneumonia. The fourth patient did not develop CMV pneumonia, but his urine became persistently positive for CMV-DNA soon after the BMT, whereas the serum was negative. A relationship was found between the occurrence of pneumonia and the serum level of CMV-DNA. CMV-DNA was also detected in three of six pneumonia patients whose anti-CMV IgM antibodies were elevated in the circulation. Sera from the 16 normal subjects were negative for CMV-DNA, regardless of their being seropositive or seronegative for CMV. While it had been previously thought that CMV did not exist in serum, we detected CMV-DNA in serum by PCR in the active disease stage. Our results suggest that PCR would be useful for the early diagnosis of CMV pneumonia and in monitoring its course.

Adolescent↗