Biomedical subjects

K Tajima

Publications and source records attributed to K Tajima.

At least 271 records · Page 15Linked to original sources

PubMed1994

Mortality among inhabitants of an HTLV-I endemic area in Japan.

A community-based cohort study was conducted to clarify the risk of human T-cell leukemia virus type I (HTLV-I) infection for cause-specific deaths. A total of 1,997 individuals (751 men and 1,246 women) aged 30 or older in A-Island, Nagasaki Prefecture, Japan who had voluntarily attended annual mass health examinations, including serum HTLV-I antibody test, were followed up for a mean period of 5.3 years. In a Cox proportional hazards analysis adjusted for age at baseline, the HTLV-I seropositivity was found to be associated with mortality from all causes in men (hazard ratio (HR) 1.89; 95% confidence interval (CI) 1.01-3.54) and women (HR 1.94; 95% CI 1.16-3.22). When the effects of 2 deaths (1 man and 1 woman) from adult T-cell leukemia/lymphoma (ATL) were excluded, the mortality risk decreased slightly but was still significantly or marginally significantly greater than 1 in both men (HR 1.77; 95% CI 0.93-3.37) and women (HR 1.87; 95% CI 1.12-3.12). Further analysis of cause-specific deaths revealed a significant increase in the risk for non-neoplastic diseases but not for neoplasms excluding ATL. These findings suggest that long-term HTLV-I infection represents a health hazard greater than just that for the development of ATL. It was difficult, however, to draw a conclusion regarding the association between HTLV-I infection and cancer risk, because the number of cancer deaths was small and the incidence of cancer was not investigated.

Adult↗

PubMed1994

Sarcomatoid carcinoma of the urinary tract.

Sarcomatoid carcinoma is a rare variant of malignant tumor arising from the urinary tract. This tumor had been termed carcinosarcoma because of its carcinomatous and sarcomatous components. There is still some confusion in the terminology between true carcinosarcoma and sarcomatoid carcinoma; however, the latter is now regarded as primarily a malignant epithelial tumor with pseudosarcomatous transformation. Four cases of sarcomatoid carcinoma arising from the urinary tract are reported. The patients were a 77 year old female, and three males aged 62, 69 and 80 years. All but the eldest patient complained of gross hematuria. Surgical removal was performed in the younger three cases, and an autopsy was done in the remaining case. All the tumors were macroscopically polypoid. Histopathologic examination revealed fasciculated spindle-cell tumors with myxoid stroma or malignant fibrous histiocytoma-like spindle cell tumors. The epithelial nature was proven in these sarcomatous cells by immunohistochemical and/or electron-microscopic examinations. Only a small amount of squamous cell carcinoma components was also evident in the latter three cases. Although the younger three patients were alive at 44, 23 and 39 months' follow-up, respectively, constant careful monitoring is recommended.

Aged↗

PubMed1994

Human T lymphotropic virus type 1 uveitis.

The human retroviruses, HTLV-I and HIV, are playing clinically important roles in a variety of ocular disorders, particularly in uveitis. Both viruses are integrated in the genome of infected T cells. HIV-I infection causes the death of the infected T cells, thereby affecting the host defence system and causing AIDS. Subsequent opportunistic infections of ocular tissues, such as CMV retinitis, are a serious problem in clinical ophthalmology all over the world. Another human retrovirus, HTLV-I, has been known as the causative agent of T cell malignancies (ATL and T cell lymphoma) and chronic myelopathy (HAM/TSP), and is now recognised as a causative agent for a specific type of intraocular inflammation characterised by vitreous opacities with mild iritis and mild retinal vasculitis (HTLV-I uveitis). The mechanism by which HTLV-I causes uveitis is still unknown, but our recent data suggest that it is most probably an immune mediated mechanism by activated CD4 T cells infected with the virus. HTLV-I uveitis, therefore, may implicate a significant role of retroviruses in autoimmune diseases and further the pathogenesis of diseases with infection/autoimmune overlap.

HIV Infections↗

PubMed1994

Regioselective cleavage reaction of the aromatic methylenedioxy ring. VI. Synthesis of phenothiazine analogues by using the cleavage reaction with sodium methoxide-thiols in dimethyl sulfoxide and evaluation of their biological activities.

The reactions of aromatic methylenedioxy compounds containing electron-withdrawing groups with sodium methoxide-thiols in dimethyl sulfoxide gave 3- and 4-hydroxybenzene derivatives in good yield by regioselective attack of the thiolate ions on the methylenedioxy ring. The formation mechanism and the reactivity of thiolate ions in the cleavage reaction of the methylenedioxy ring are discussed. Various biologically active compounds, 32a, 32d, 36b, 38b, 41b and 44-47, were prepared from the 4-hydroxybenzene derivatives and their Ca2+ antagonistic activities were evaluated. Among these compounds, 2-(2-bromophenylthiomethoxy)-10-(2-diethylaminoacetyl)-3- methoxyphenothiazine (46) showed the most potent Ca2+ antagonistic activity. Biological activity could be conveniently evaluated by measurement of the peak height of the vanadyl ion (+4 oxidation ion) signal produced by redox reaction between the phenothiazine derivatives and vanadate ion +5 oxidation ion) with ESR spectroscopy.

Animals↗

PubMed1994

Efficacy of gas purging for titanium casting.

Oxygen density in the melting atmosphere, oxygen uptake, hardness and castability of pure titanium castings were examined to evaluate the efficacy of gas purging in reducing contamination from the melting atmosphere and mold, using a newly developed titanium casting machine in which the double purging process is systematized. The adoption of a double purging operation resulted in an extremely low oxygen density in the melting atmosphere, followed by extremely low oxygen uptake in the casting when compared with the conventional titanium casting machine. When the purging operation was used, the surface hardness was markedly reduced, although there was no difference in castability. From these results, it was suggested that the newly developed titanium casting machine with the double purging operation could produce better titanium castings with less contamination due to the mold and gas impurities in melting atmosphere.

Argon↗

PubMed1994

A multicenter case-control study of HTLV-I associated uveitis. Study Group for HTLV-I Associated Ocular Diseases.

To elucidate the epidemiology of human T-lymphotropic virus type I (HTLV-I) associated uveitis (HAU), a multicenter case-control study was carried out by the collaboration of university hospitals throughout Kyushu and Okinawa in southwestern Japan where HTLV-I is endemic; two institutions in the non-endemic metropolitan areas of Tokyo and Yokohama also participated. A total of 426 cases of endogenous uveitis were registered during the five-month period between September 1992 and January 1993; the etiology and clinical entity of about half of the cases were definable, and for the remaining half were unknown. Assessment of antibodies to HTLV-I revealed that the group of entity-undefined uveitis cases showed a significantly high seroprevalence when compared with age- and sex-matched controls. Estimate of the risk of HTLV-I provided supportive evidence for its etiologic contribution to a considerable proportion of hitherto undefined isolated uveitis cases. The prevalence of HAU thus defined was found to correspond to the seroprevalence in the relevant areas. Occasional cases were found among residents in the nonendemic metropolitan areas who had moved from the endemic areas.

Adolescent↗

PubMed1994

[Repair of total anomalous pulmonary venous connection in asplenia syndrome without cardiopulmonary bypass].

Two infants with asplenia syndrome underwent repair of total anomalous pulmonary venous connection (TAPVC) without cardiopulmonary bypass (CPB). Both patients had other complex cardiac anomalies; pulmonary atresia, univentricular heart, etc. The first patient previously received a left modified Blalock-Taussig shunt. The common chamber (pulmonary venous confluence) was anastomosed to the right side atrium using a side-biting clamp. Though both patients had good postoperative course immediately after surgery, they subsequently died 43 days and 4 months after surgery, respectively. We conclude that relief of TAPVC can be accomplished without CPB and allowing easier and simpler postoperative care.

Abnormalities, Multiple↗

PubMed1994

Human T-lymphotropic virus type I uveitis.

In addition to adult T-cell leukemia (ATL) and chronic myelopathy (HAM/TSP), our current study indicates that human T lymphotropic virus type I (HTLV-I) is a causative agent for a specific type of uveitis with unknown etiology (idiopathic uveitis). The present paper describes the seroepidemiological, clinical, and molecular biological evidences that indicate uveitis seen in HTLV-I asymptomatic carriers (HTLV-I uveitis) is a distinct clinical entity. In an HTLV-I endemic area in Japan, the seroprevalence of HTLV-I in idiopathic uveitis was 38%, while those in uveitis with defined etiology and in non-uveitic ocular diseases were 10% and 19%, respectively. Strikingly, the HTLV-I seroprevalence in younger aged patients (20-49 years) with idiopathic uveitis was 49%, while only 8% in the control group (P < 0.001). A very similar observation was recorded even in HTLV-I less endemic area, suggesting that HTLV-I infection plays a role as a risk factor for idiopathic uveitis. Clinical analysis revealed that an intermediate uveitis characterized by moderate opacities in the vitreous body and retinal vasculitis was seen in the majority the patients. The proviral DNA of HTLV-I was detected from inflammatory cells in the eye of all tested patients using PCR technique. These data thus indicate that HTLV-I is closely related to a certain type of uveitis and the uveitis (HTLV-I uveitis) is a distinct clinical entity.

Adolescent↗

PubMed1994

[Study on clinical effects of tosufloxacin (TFLX) and the long-term low dose therapy for the prophylaxis of recurrent urinary tract infection].

Forty five patients with complicated urinary tract infections were treated with tosufloxacin (TFLX) in the initial antibacterial treatment. Excellent and moderate responses were obtained in 39 patients (86.7%). No side effects were seen. Clinical efficacy and safety of long-term preventive administration of TFLX (150mg, a day) were also examined in 39 patients who showed an excellent or a moderate response in the initial treatment. The period of the administration ranged from 28 to 112 days (average; 55 days). The rate of preventing recurrence of urinary tract infection was 92.3% on the last day of treatment. These findings suggested that TFLX was useful not only in treating the patients with complicated urinary tract infections but also in preventing recurrence of urinary tract infection.

Adult↗

PubMed1993

Clinical and immunologic features of human T-cell lymphotropic virus type I uveitis.

The clinical features of idiopathic uveitis were compared by the seropositivity for human T-cell lymphotropic virus type I. The statistical analysis of various clinical variables disclosed that the uveitis seen in seropositive patients (93 patients) had a significantly higher incidence of floaters, vitreous opacities, retinal vasculitis, and intermediate uveitis than that in seronegative patients (222 patients) (P < .05). The odds ratios of the virus infection for these clinical manifestations were high and statistically significant, suggesting that the virus infection has a role as a risk factor for the development of these clinical manifestations. Although visual acuity at the initial examination was almost equal between the two groups, after the therapy with topical or systemic corticosteroids, or both, visual acuity in seropositive patients was much better than that in seronegative patients. The surface phenotype of peripheral lymphocytes in the two groups was compared as follows: CD4-positive T lymphocytes (P < .05), CD4/8 ratio (P < .01), and CD25-positive T lymphocytes (P < .05) were significantly higher in seropositive patients than in seronegative patients.

Adult↗

PubMed1993

Absence of HTLV-I infection among seronegative subjects in an endemic area of Japan.

To examine the prevalence of infection by human T-cell leukemia virus type I (HTLV-I) among seronegative subjects, healthy subjects on Tsushima Island, Japan, where the infection is endemic, were evaluated. A total of 209 healthy adults were examined for HTLV-I provirus in peripheral blood mononuclear cells by the polymerase chain reaction (PCR), as well as for anti-HTLV-I antibodies by the particle agglutination (PA) method, the enzyme-linked immunosorbent assay (ELISA) and by immunofluorescence analysis (IF). A total of 76 subjects were positive and 133 were negative for the provirus, showing a close correlation with the results of 3 assays for anti-HTLV-I serum antibodies. None of the seronegative subjects reacted positively on PCR analysis. These observations indicate that seronegative HTLV-I carriers are rare in an area of Japan in which this viral infection is endemic.

Adult↗

PubMed1993

Calcium entry blocking activities of MPC-1304 and of its enantiomers and metabolites.

The Ca2+ entry blocking effects of MPC-1304, a new Ca2+ entry blocker of the 1,4-dihydropyridine type, and of its (S) and (R) enantiomers and metabolites were examined on Ca(2+)-induced contractions in isolated rabbit arteries. The Ca2+ entry blocking activity of the (S) enantiomer of MPC-1304 was approximately 150 times greater than that of its (R) enantiomer. Likewise, the antihypertensive effect of the (S) enantiomer was twice as great as that of MPC-1304 (racemate) in conscious spontaneously hypertensive rats, while the (R) enantiomer was ineffective. Thus, most of the pharmacological activity of MPC-1304 resides in its (S) configuration. The main metabolic products of MPC-1304 also inhibited the Ca(2+)-induced contraction in the isolated vascular smooth muscles. These active metabolites showed a stereoselectivity similar to that of MPC-1304 for Ca2+ entry blocking activity, and may contribute to the potent antihypertensive action of MPC-1304.

Animals↗

PubMed1993

Cytochrome P-450-butyl peroxide complex detected by ESR.

ESR measurements were performed for the reaction systems composed of t- or n-butylhydroperoxide and cytochrome P-450 (UT-2), purified from rat liver microsomes. On addition of n-butylhydroperoxide to the P-450 at pH 7.4, ESR signal due to a ferric low-spin species (g1 = 2.29, g2 = 2.24 and g3 = 1.96) was recorded. The observed g-parameters agreed well with those of a model thiolate-heme-iron(III)-peroxide complex, Fe(III)TPP(-S-TGE) (-OO-t-butyl) (g1 = 2.285, g2 = 2.198 and g3 = 1.959). In terms of the g-parameters, the new P-450 complex was concluded to be a P-450-butyl peroxide adduct, in which a butyl peroxide anion ligates at the sixth position of heme iron(III).

Animals↗

PubMed1993

Changes in histopathological features of gastric carcinoma over a 26-year period (1965-1990).

Epidemiological study has shown that the incidence rate of gastric carcinoma in Japan has declined recently. To explore the factors that have influenced this decrease, the changing pattern in clinico-pathological features of gastric carcinoma was studied from the epidemiological point of view. The 5,015 cases of gastric carcinoma treated with gastrectomy at Aichi Cancer Center Hospital from 1965-1990 were divided into two histopathological types: the well-differentiated and other types. Proportional distribution was compared over the three different periods (1965-1973, 1974-1982, 1983-1990) according to the clinico-pathological features of the gastric carcinoma, i.e., sex, age, lesional location, etc. The recent relative decline of gastric carcinoma is due mainly to the decline of carcinoma of the well-differentiated type. This decline has been highly correlated to the decline in carcinoma of the antrum, which has been the most common in Japan. This changing pattern of clinicopathological features of Japanese gastric carcinoma might be affected by the change of exposure patterns to epidemiological factors, i.e., a Westernizing diet.

Age Factors↗

PubMed1993

A hospital-based case-control study of breast-cancer risk factors by estrogen and progesterone receptor status.

It has been proposed that breast cancers may differ in their pathogenesis and etiology according to their estrogen receptor (ER) and progesterone receptor (PR) status. This hospital-based case-control study in Japan assessed the relationship between known and suspected breast-cancer risk factors and ER and PR status. Information on risk factors was collected from histologically confirmed breast-cancer cases (n = 519) and from cancer-free controls (n = 9,506). Of 160 cases with known ER status, 58 percent were ER-positive; 38 percent of 157 cases with known PR status were PR-positive. No statistically significant differences were found between ER-positive cf ER-negative cases. However, statistically significant differences between PR-positive cf PR-negative cases were observed for number of full-term pregnancies (P = 0.01), menstrual regularity as a teenager (P = 0.024), and occupation as housewife (P = 0.036). Borderline differences were observed for age at menopause (P = 0.074), and age at menarche (P = 0.083). This study provides some evidence that etiologic distinctions may be greater between PR-positive and PR-negative breast cancers than between ER-positive and ER-negative breast cancers.

Adult↗

PubMed1993

Cardiopulmonary bypass and cellular immunity: changes in lymphocyte subsets and natural killer cell activity.

To investigate whether cell-mediated immunity responses are suppressed or activated by the effect of cardiopulmonary bypass (CPB), we studied peripheral blood lymphocyte subsets and antibody-dependent cell-mediated cytotoxicity in 52 adult patients who had undergone open heart operations. Lymphocyte function also was studied with regard to mixed lymphocyte reaction, which indicates the amount of DNA synthesis of lymphocytes, and natural killer (NK) cytotoxicity, which represents the killing activity of NK cells on the tumor cells (K-562), in 11 patients. The total T lymphocyte (OKT3+ and OKT11+) number showed no significant change during CPB. Suppressor/cytotoxic T cell (OKT8+) and NK cell (Leu7+ and Leu11+) numbers were found to be remarkably increased. However, helper/inducer T cell (OKT4+) and B cell (Leu12+) numbers were decreased during CPB. Antibody-dependent cell-mediated cytotoxicity was elevated during CPB. All of these changes were almost returned to the preoperative levels by the seventh day after operation. Mixed lymphocyte reaction and NK cytotoxicity were also activated during CPB. The results show that heart operations in which cardiopulmonary bypass is used are associated with activation of cytotoxic cell-mediated immunity.

Antibody-Dependent Cell Cytotoxicity↗

PubMed1993

A differential heat-conduction microcalorimeter for heat-capacity measurements of fluids.

A heat-conduction calorimeter has been developed for measuring small changes in heat capacity of milligram samples of membrane lipid dispersed in water as a function of temperature. The operation of the instrument is based on the principle that the thermal response of the sample to a short (10 s), electrically generated heat burst is a function of the diffusivity of the sample. Modeling studies of the instrument's performance have revealed that the output response after the heat burst is a function of only the heat capacity, rho Cp. Calibration of the instrument experimentally confirmed this behavior. This feature obviated the need to measure the thermal conductivity in order to determine rho Cp from the diffusivity equation, eta = lambda/rho Cp. The calorimeter has the following characteristics: reproducibility of loading: +/- 400 microJ/C degrees.cm3; baseline stability: +/- 10 microJ/C degrees.cm3 per 36 h; resolution (+/- 1 S.D.): +/- 50 microJ/C degrees.cm3; sample size 600 microliters.

Calibration↗

PubMed1993

Critical temperature for unilamellar vesicle formation in dimyristoylphosphatidylcholine dispersions from specific heat measurements.

Using a heat conduction calorimeter with very high resolution (+/- 0.00005 J/degrees C.cm3), we have measured the specific heat CpL between 25 and 35 degrees C of dimyristoylphosphatidylcholine (DMPC) in aqueous dispersions. Previous studies of the temperature dependence of the chemical potential of DMPC in the L alpha phase (lamellar, liquid crystalline) indicated that a dispersion consisting only of unilamellar vesicles forms spontaneously at a critical temperature T* of 29.0 degrees C. Our present measurements show an anomaly in CpL between 28.70 and 29.50 degrees C: the curve for CpL versus T first decreases and then exhibits an inflection point at 28.96 degrees C before it flattens. This anomaly is attributed to the transformation from multilamellar dispersion to unilamellar vesicles at T* = 28.96 degrees C. Two independent properties of the CpL data also indicate T* is a critical point for the formation of unilamellar vesicles: (a) the time to reach equilibrium upon changing temperature increased dramatically between 28.7 and 28.96 degrees C, increasing as (T* - T)-1; at T > T* the dramatic "slowing-down" phenomenon was not observed. This slowing-down near T* is a general characteristic of critical phenomena. (b) The free energy change for the multilamellar-unilamellar transformation was obtained from the CpL-T data over this temperature interval and found to be 3.2 J/mol or 0.016 ergs/cm2 of bilayer, in agreement with other estimates of the interaction energy between neutral bilayers. We conclude with a discussion of the implications for membrane bilayer stability of these newly identified dynamic properties of the transformation.

Biophysical Phenomena↗