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Biomedical subjects

K Takatsuki

Publications and source records attributed to K Takatsuki.

At least 235 records · Page 13Linked to original sources
PubMed1991

Serological discrimination between HTLV-I and HTLV-II antibodies by ELISA using synthetic peptides as antigens.

Using the peptides from amino acids 100-130 of the HTLV-I gag protein, 175-199 of the HTLV-I env protein and the corresponding peptides of HTLV-II (amino acids 106 to 135 of the gag protein and 171 to 196 of the env protein), we tested for reactivity against antibodies by enzyme immunoassay in sera from HTLV-I and HTLV-II carriers. The peptides derived from the env proteins have high specificity for antibody binding. The peptide based on amino acids 175-199 of HTLV-I reacted with antibodies in sera from all HTLV-I carriers, and the peptide composed of amino acids 171-196 of HTLV-II reacted with antibodies in sera from all HTLV-II carriers. For the peptides derived from the gag proteins, we observed some cross-reactivity in sera from persons with anti-HTLV-I and anti-HTLV-II, due to antibody binding to the peptide corresponding to 12 amino acids from the C-terminal end of the gag protein. Separate enzyme immunoassays that used the four synthetic peptides as antigens clearly distinguished between serum with antibodies to HTLV-I or HTLV-II in various individuals and excluded false positive results using the particle agglutination assay that used a whole-virus lysate of HTLV-I as antigen.

Amino Acid Sequence↗
PubMed1991

Aggravation of subclinical diabetes insipidus during pregnancy.

BACKGROUND: Transient polyuria and polydipsia during pregnancy are rare, and their cause is not entirely clear. Possible explanations include the exacerbation of preexisting abnormalities in the secretion or action of vasopressin and abnormally large increases in plasma vasopressinase activity. METHODS: We studied two women in whom overt polyuria and polydipsia developed during the third trimester of pregnancy and disappeared after delivery. The secretion and action of vasopressin were studied both when the women had polyuria and polydipsia and later, when their water intake and urine volume were normal. RESULTS: One patient had partial nephrogenic diabetes insipidus. She had little increase in urine osmolality in response to water deprivation, hypertonic-saline infusion, and vasopressin injection and no response to desmopressin acetate (1-deamino-8-D-arginine vasopressin) during the immediate postpartum period. Her basal and stimulated plasma vasopressin concentrations were high (16.5 to 203.4 pmol per liter) before and during hypertonic-saline infusion 30 months post partum. The other patient had partial neurogenic diabetes insipidus. She had subnormal basal plasma vasopressin concentrations, a subnormal increase in the plasma vasopressin level and a subnormal decrease in urine flow in response to the administration of vasopressin, and a normal response to desmopressin. After pregnancy, when her urine volume was normal, she had no increase in plasma vasopressin in response to hypertonic-saline infusion, but she had a normal rise in the plasma vasopressin level and a normal renal response to vasopressin administration. CONCLUSIONS: Pregnancy may unmask subclinical forms of both nephrogenic and neurogenic diabetes insipidus. This exacerbation may result from both increased vasopressinase activity and diminished renal responsiveness to vasopressin.

Adult↗
PubMed1991

Gas chromatographic-mass spectrometric determination of oxolinic acid in fish using selected ion monitoring.

A gas chromatographic-mass spectrometric (GC-MS) method is described for the determination of oxolinic acid in fish tissues. oxolinic acid is reduced with sodium tetrahydroborate to permit GC analysis. The sample is homogenized with phosphate buffer (pH 6) and extracted with ethyl acetate. The extract is partitioned between sodium hydrogencarbonate solution and the aqueous phase is acidified and re-extracted with ethyl acetate. The residue from the ethyl acetate extract is dissolved in methanol and reduced with sodium tetrahydroborate. The reduction product is extracted with diethyl ether and analysed by GC-MS in the selected ion monitoring mode for the ions at m/z 204, 219 and 176. The detection limit is 0.001 mg/kg and the recoveries were 95.6% [relative standard deviation (R.S.D.) 7.7%] at 0.1 mg/kg and 72.9% (R.S.D. 13.3%) at 0.01 mg/kg fortification levels in fish.

Borohydrides↗
PubMed1991

Leukaemia of novel gastrointestinal T-lymphocyte population infected with HTLV-I.

In a 72-year-old man with watery diarrhoea and leukocytosis the proliferation of abnormal cells was studied in specimens obtained by endoscopic biopsy of the gastrointestinal tract. Flow cytometry of leukaemia cells revealed a monoclonal expansion of "double-negative" (CD4-, CD8-) cells bearing T-cell receptor (TCR) alpha beta products. Southern blotting confirmed monoclonal integration of HTLV-I. A novel T-cell subset of double-negative TCR alpha beta cells in the gastrointestinal tract in adult man may be a target for HTLV-I infection.

Aged↗
PubMed1991

Role of leukocytes in the activation of intravascular coagulation in patients with septicemia.

To elucidate the role of leukocytes in intravascular coagulation in patients with septicemia, plasma levels of thrombin-antithrombin III complex (TAT), soluble fibrin monomer complex (SFMC) and fibrinogen (Fbg) were determined in 33 patients with septicemia. Twenty of 33 patients revealed marked leukopenia caused by suppression of hematopoiesis by the administration of chemotherapeutic agents for the treatment of hematological malignancies; the total leukocyte count of these patients was less than 1,000/microliters. Thirteen of 33 patients showed normal or increased leukocyte counts. Plasma levels of TAT and SFMC in septicemic patients without leukopenia were significantly higher than in patients with leukopenia. Although plasma TAT and SFMC levels correlated well with the number of leukocytes, a more significant positive correlation was found between the number of monocytes and the levels of TAT and SFMC. Plasma levels of Fbg were significantly lower in patients without leukopenia than in patients with leukopenia. No significant correlation was found between the number of leukocytes and the levels of Fbg. However, a significant negative correlation was found between the number of monocytes and the levels of Fbg. TAT levels did not correlate with the number of platelets. The fibrinolytic system was activated only in septicemic patients without leukopenia, which may be explained by secondary fibrinolysis following leukocyte-activated coagulation. These findings suggest that leukocytes, in particular monocytes, may play a critical role in the pathogenesis of intravascular coagulation in septicemia.

Antithrombin III↗
PubMed1991

Alteration of nuclear proto-oncogene expression by erythropoietin (Epo) in Epo-responsive murine cell lines.

The signal transduction system of erythropoietin (Epo) and the accompanying molecular control mechanism of proliferation and differentiation of erythroid progenitors remains largely unknown. In this study, the effect of Epo on the expression of nuclear oncogenes was investigated in two murine cell lines which respond to the hormone in different ways: ELM-I-1 cells proliferate independently of Epo, but differentiate in response to the hormone, while the growth of DA-1ER cells is absolutely dependent on Epo or interleukin (IL) 3. The cell lines were stimulated with Epo or IL-3, and total RNA was extracted. Then expression of nuclear proto-oncogenes (c-myc, c-fos and c-myb) was analyzed by northern blotting. The change in c-fos expression observed during the first two h following stimulation with either stimulant were common to both cell lines; a rapid and temporary increment. Before stimulation, c-myc and c-myb were strongly expressed in both lines. No apparent change in c-myc expression was observed during the first two h of stimulation, while c-myb expression in ELM-I-1 cells was slightly reduced 1 h after stimulation with Epo but not with IL-3. Three days after stimulation with Epo, but not with IL-3, only ELM-I-1 produced hemoglobin and expressed a lower amount of c-myb mRNA. These data suggest the importance of c-fos in the early signaling system of Epo, and the involvement of c-myb in erythroid differentiation but not in proliferation.

Animals↗
PubMed1991

Concanavalin A-stimulated expression of gangliosides with GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta structure in murine thymocytes.

We analysed the glycolipids of mouse thymocytes before and after Concanavalin A (Con A) or recombinant interleukin-2 (rIL-2) stimulation by TLC-immunostaining with carbohydrate-specific antiglycolipid antibodies. The thymocytes were cultured in serum-free medium in the presence of 500 ng ml-1 Con A, 10 U ml-1 rIL-2 or Con A plus rIL-2 for 6, 12, 24, 48, and 72 h, and were found to start proliferating 24 h after cultivation in the presence of Con A or Con A plus rIL-2, the maximum levels being reached at 72 h and 48 h, respectively, in a thymidine uptake experiment. The concentrations of II3Neu-Gg4Cer, Gg4Cer and IV3GalNAc alpha-Gb4Cer after 48 h Con A stimulation were found to be at almost the original levels. Conversely, II3Neu-Gg3Cer, which was not detected in the thymocytes at the start, began to appear after 48 h stimulation with Con A and Con A plus rIL-2, and IV3Neu-Gg5Cer in the cells 48 h after stimulation with Con A and Con A plus rIL-2 has increased to 41 and 44 times higher than in the original cells, respectively, as judged on TLC-immunostaining with monoclonal antibody YHD-06, which detects the GalNAc beta 1-4(NeuAc or NeuGc alpha 2-3)Gal beta-structure. These results indicate that the increased synthesis of both gangliosides, in other words, the activation of N-acetylgalactosaminyltransferase, is associated with the mitogen-induced proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Insulin and glucagon therapy of acute hepatic failure.

When insulin and glucagon are administered to rats with severe liver injury, survival is enhanced with an attenuation of the liver injury compared to that of untreated controls. In rats with acute liver injury both hormones produce a rapid normalization of hepatic protein content following initiation of DNA synthesis. When rats receive both hormones after partial hepatectomy, the first burst of DNA synthesis reaches a maximum earlier than that seen in controls. Both hormones enhance the increment of hepatic putrescine essential for DNA synthesis through activation of ornithine decaroxylase and/or spermidine-N1-acetyltransferase. The enhancement of putrescine content by each hormone is additive. Putrescine supplementation promotes hepatic DNA synthesis after hepatectomy. Based on these data, we conclude that a combination of insulin and glucagon is effective in the therapy of acute hepatic failure in rats. The restoration of liver function as well as the stimulation of liver cell proliferation via putrescine production may contribute to this effect.

Acetyltransferases↗
PubMed1991

Characterization of autoantibodies to the CD4 molecule in human immunodeficiency virus infection.

Autoantibodies to the CD4 protein, which serves as a receptor for the human immunodeficiency virus (HIV) on the surface of target cells, were found in patients with different stages of HIV disease. Using recombinant soluble CD4 (rCD4) antigen in a enzyme-linked immunosorbent assay (ELISA), we detected serum anti-CD4 antibodies in approximately 20% of HIV-1 infected patients and 13% of HIV-2 infected patients. There was no correlation between the presence of anti-CD4 antibodies and the stage of HIV disease, serum IgG concentration, number of peripheral blood CD4 positive lymphocytes, or CD4/CD8 lymphocyte ratios in HIV-1 infected patients. Immunoaffinity purified anti-CD4 antibody failed to bind to CD4 positive cells using flow cytometric analysis. However, this antibody could weakly bind to CD4 positive cells that had been preincubated with purified recombinant gp120 (rgp120). In addition, using an ELISA system, we found that the binding of purified patient anti-CD4 antibody to rCD4 was increased in the presence of rgp120. Similar increased binding was observed with the anti-CD4 monoclonal antibody OKT4, but not with anti-Leu3a. These data suggest that a conformational change in the C-terminal domains of CD4 may be induced by gp120 binding and could lead to development of anti-CD4 antibodies.

Autoantibodies↗
PubMed1991

Effects of hypergravity on proliferation and differentiation of osteoblast-like cells.

We investigated the effects of hypergravity on DNA synthesis and alkaline phosphatase (ALP) activity in cloned osteoblast-like cells, MC3T3-E1. Hypergravity (5 x g) stimulated DNA synthesis in these cells in a time-dependent manner and increased it approximately up to 150% of that of the control (1 x g). 12-O-Tetra-decanoylphorbol-13-acetate (TPA), a protein kinase C activator, and insulin-like growth factor I (IGF-I) enhanced DNA synthesis additively with hypergravity (5 x g). An increase in ALP activity induced by 10% fetal calf serum (FCS) was suppressed by hypergravity (2 x g, 5 x g). Five x g completely suppressed the increase in ALP activity. TPA and hypergravity (2 x g) suppressed the increase in ALP activity induced by FCS additively. Hypergravity (5 x g) showed no significant effect on cAMP nor cGMP production in these cells, but increased prostaglandin E2 (PGE2) production. Exogenous PGE2 stimulated DNA synthesis in these cells but had little effect on 10% FCS-induced ALP activity. These results suggest that hypergravity stimulates proliferation but suppresses differentiation of osteoblast-like cells through a pathway independent of the activation of protein kinase C and the production of cyclic nucleotides, and that hypergravity and IGF-I stimulate proliferation of these cells through an independent signal transduction pathway. Moreover, our data strongly suggest that PGE2 mediates the signalling of hypergravity on the proliferation of osteoblast-like cells.

Alkaline Phosphatase↗
PubMed1991

Serum beta 2-microglobulin in patients with adult T-cell leukemia.

Thirty-seven patients with adult T-cell leukemia had serum beta 2-microglobulin (beta 2M) estimated at presentation. A significant association was found between beta 2M and the subtypes of the disease: beta 2M in the acute type is significantly higher than in the chronic and smoldering types (p less than 0.01), and beta 2M in the lymphoma type is apparently higher than in the chronic and smoldering types, although the difference between the lymphoma and chronic types was not statistically significant. An apparent reduction in beta 2M levels after chemotherapy was observed in 7 patients who reached partial or complete remission. One patient who was resistant to chemotherapy showed elevated beta 2M values even after intensive chemotherapy. In another patient, who attained partial remission with a concordant reduction in beta 2M, renewed elevation of beta 2M was observed in parallel with exacerbation of other parameters such as lactate dehydrogenase (LDH), WBC, calcium and clinical manifestations. Correlation analysis was carried out between beta 2M, LDH, calcium, lymphoid cell count and the grade of clinical severity. The beta 2M level was moderately correlated with LDH, calcium, the grade of clinical severity but not with the lymphoid cell count. The clinical severity also correlated with LDH and calcium but to a lesser extent than with beta 2M. These data support the use of the beta 2M in the evaluation of adult T-cell leukemia.

Anemia, Refractory, with Excess of Blasts↗
PubMed1991

Pseudo-nonsecretory multiple myeloma with light chain deposition disease.

A diagnosis of nonsecretory myeloma was established in two patients with anemia and proteinuria on the basis of the suppression of polyclonal immunoglobulins and the increase of plasma cells in the bone marrow. No paraprotein was detected in the serum or concentrated urine of these patients. However, a plaque-forming assay of bone marrow cells showed the secretion of monoclonal immunoglobulin by the myeloma cells. Moreover, renal biopsies from both patients indicated the deposition of monoclonal light chains in the glomerular mesangium and basement membrane, as well as in the tubular basement membrane, a pattern consistent with light-chain deposition disease. These observations suggested that the secreted paraprotein disappeared rapidly as a result of enhanced catabolism or deposition in organs such as the kidney, producing severe proteinuria and chronic renal failure. The plaque-forming assay is a useful technique for the demonstration of this type of nonsecretory myeloma, pseudo-nonsecretory myeloma.

Aged↗
PubMed1991

Treatment of myelodysplastic syndromes with orally administered 1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate.

1-beta-D-Arabinofuranosylcytosine-5'-stearylphosphate (fosteabine) was administered orally to patients with myelodysplastic syndromes (MDS); refractory anemia with excess of blasts (RAEB), RAEB in transformation, acute leukemia derived from RAEB and chronic myelomonocytic leukemia, in an early phase II study in a multi-institutional study. Among 62 evaluable patients, 2 patients achieved a complete remission, 6 a good response and 8 partial response by daily oral administration of 100-200 mg of fosteabine. The overall response rate was 25.8%. The response rates were almost the same among the four subtypes of MDS. Responses were reached 2-23 weeks (median, 8 weeks) after the start of therapy and continued for 3-50 weeks (median, 10 weeks). Major side effects were myelosuppression and gastrointestinal toxicities. In spite of the disadvantages, such as unpredictable absorption, this newly developed orally administrable cytarabine analogue will be a useful drug in the treatment of MDS.

Adult↗
PubMed1991

Prolactin secretion in patients with idiopathic diabetes insipidus.

It has been demonstrated that hyperprolactinemia is sometimes present even in patients with idiopathic diabetes insipidus (DI). In this study, we examined the responses of serum prolactin (PRL) to hypertonic saline infusion and TRH injection in 11 patients with idiopathic DI diagnosed by clinical examinations. Serum sodium in these patients (147.5 +/- 3.2 mEq/L) was significantly higher at baseline than in normal subjects (139.7 +/- 2.4 mEq/L). The plasma arginine vasopressin (AVP) level was significantly lower in DI (0.42 +/- 0.24 pg/ml) at baseline than in normal subjects (2.53 +/- 1.03 pg/ml). However, the serum PRL level in both groups did not differ significantly except in one patient with idiopathic DI (35.6 ng/ml). There was no significant correlation between the basal serum sodium and basal serum PRL in either group. After an infusion of hypertonic saline, the serum sodium level gradually increased to 155.6 +/- 3.4 mEq/L in DI and to 146.5 +/- 4.3 mEq/L in the normal subjects. However, this increase did not affect PRL secretion in either group. PRL response to TRH was essentially normal in all patients with idiopathic DI. These results indicate that the secretion of PRL is not generally affected by chronic mild hypernatremic hypovolemia in the patients with idiopathic DI.

Adolescent↗
PubMed1991

Regulatory mechanisms for the expression of a functional beta chain of interleukin 2 receptor on T4 chronic lymphocytic leukemia cells.

Monoclonal antibodies, each recognizing interleukin 2 receptor (IL-2R) alpha, or beta, were used to see the regulatory mechanisms of the expressions on leukemic cells from a patient with T4 chronic lymphocytic leukemia (T4-CLL). Cells from this patient expressed only IL-2R beta, and the expression was enhanced by medium cultivation. IL-1 enhanced the expression of not only IL-2R beta but also IL-2R alpha on the cells. Binding studies using 125I-IL-2 showed the presence of an intermediate receptor (734 sites/cell, Kd = 1.2 nM) and a few high-affinity receptor (172 sites/cell, Kd = 132 pM) on cells cultured with IL-1. IL-2 and IL-1 synergistically promoted the proliferation of the cells, suggesting that the induced IL-2R was functional. In addition, anti-IL-1 antibodies inhibited IL-2R beta expression by cultured cells, suggesting that it was dependent on IL-1 produced by the leukemic cells. These findings suggested that IL-1 might enhance the expression of IL-2R beta in a subset of human T cells, and implied a role of IL-1 in the proliferation of the leukemic T cells.

Aged↗