PubMed Health⌕ Search

Biomedical subjects

T Sakano

Publications and source records attributed to T Sakano.

At least 73 records · Page 4Linked to original sources
PubMed1988

Simultaneous determination of vitamin K1, vitamin K1 2,3-epoxide and menaquinone-4 in human plasma by high-performance liquid chromatography with fluorimetric detection.

A highly sensitive method for measuring endogenous vitamin K1, menaquinone-4 (which is one of the K2 vitamins) and vitamin K1 2,3-epoxide in human plasma was developed, based on high-performance liquid chromatography with coulometric reduction and fluorimetric detection, following extraction from plasma and purification on a Sep-Pak silica cartridge. The detection limits of vitamin K1, menaquinone-4 and vitamin K1 2,3-epoxide were 5, 5 and 8 pg per injection for the standard substances and 30, 30 and 50 pg/ml in human plasma, respectively.

Adult↗
PubMed1988

C7 deficiency and persistent haematuria.

A 14-year-old boy had persistent haematuria along with complete C7 deficiency. No significant changes in glomeruli and tubules were found in a renal biopsy specimen by light microscopy and immunofluorescence gave negative results for immune deposits. Electron microscopic examination demonstrated an attenuation of the glomerular capillary basement membrane without lamination and a diagnosis of thin basement membrane disease was made. It would be difficult to conclude that patients with C7 deficiency were predisposed to develop glomerulonephritis caused by immunologic aberrations. A family study failed to provide evidence of an association of C7 deficiency and thin basement membrane disease.

Adolescent↗
PubMed1988

Intracellular Ca2+ mobilization in immature and more mature U937 induced to differentiate by dimethyl sulfoxide or phorbol myristate acetate.

Intracellular Ca2+ mobilization in U937 cells was studied. Stimulation of immature U937 cells with leukotriene B4 (LTB4) increased intracellular Ca2+ levels, whereas stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP) failed to increase intracellular Ca2+ levels. U937 cells cultured with 1.5% dimethyl sulfoxide (DMSO) for 4 days (DMSO-U937 cells) responded to LTB4 and possessed the ability to respond to fMLP. U937 cells cultured with 1 ng/ml phorbol myristate acetate (PMA) for 4 days (PMA-U937 cells) lost the ability to respond to LTB4, although they responded to fMLP. Treatment of DMSO-U937 cells with 100 ng/ml PMA for 3 min suppressed intracellular Ca2+ increase induced by LTB4 and fMLP. The fMLP-induced Ca2+ rise in PMA-U937 cells was not suppressed by a further treatment with 100 ng/ml PMA. DMSO-U937 cells responded to inositol 1,4,5-trisphosphate (IP3), indicating that IP3 functions as a messenger of intracellular Ca2+ mobilization from endoplasmic reticulum in U937. The magnitude and duration of the rise in Ca2+ induced by IP3 in DMSO-U937 cells treated with 100 ng/ml PMA for 3 min were similar to those of the controls. When DMSO-U937 cells were Ca2+-depleted, addition of Ca2+ resulted in a transient overshoot of Ca2+ influx. However, the transient overshoot was not observed, when PMA-U937 cells were tested. These results indicate that Ca2+ efflux in PMA-U937 cells is increased by an activated exit pump, which may be directly or indirectly related to the functional state of PMA-U937 cells.

Calcium↗
PubMed1988

Linkage of K99 production and STa activity in a plasmid of an Escherichia coli porcine isolate.

An Escherichia coli strain ZP118 of porcine origin was shown to harbor a 68-megadalton (Md) plasmid coding for a colonization factor K99 and heat-stable enterotoxin (STa), and a self-transmissible 51-Md plasmid coding for drug resistance. One of the transconjugants obtained by mating between ZP118 and E. coli C was found to harbor a 90-Md plasmid coding for K99, STa and drug resistance. Restriction endonuclease analysis suggested that the 90-Md plasmid could be a recombinant between the 68-Md plasmid and the 51-Md plasmid.

Animals↗
PubMed1987

Detection of a transforming gene in spontaneous reticulum cell sarcoma of SJL/J mice: genetically linked and host-dependent neoplasia.

Spontaneous reticulum cell sarcoma (RCS) tumor induction occurs in 90% of SJL/J mice of 8-13 months of age. Tumor induction and growth has been shown to be under the influence of both H-2 and non-H-2 genes as well as the presence of an intact host T-cell system. We postulated that cellular oncogenes may play a role in the induction, growth, and characteristics of RCS. DNA-mediated gene transfer protocols were adopted to investigate the presence of transforming genes in DNA from RCS of SJL/J mice. High molecular weight DNA was isolated from these tumors as well as from brains and livers of control tumor-free SJL/J mice and transfected into NIH-3T3 mouse and F2408 rat fibroblast cell lines. Foci of transformed cells with a peculiar round morphology were scored in both rat and mouse cultures given tumor DNA, but not in those receiving DNA from normal tissues. DNA from first-cycle transformants was transfected in further cycles of transfection, giving rise to foci with similar morphological appearances and growth properties. These experiments suggest that a transforming gene, present in RCS spontaneous tumors, is involved in the malignant conversion of the transfected normal fibroblasts. The implication of these results with respect to the induction and growth properties of RCS is discussed.

Animals↗
PubMed1987

Incidence and some characteristics of fimbriae FY and 31A of Escherichia coli isolates from calves with diarrhea in Japan.

Escherichia coli isolates from calves with diarrhea (1 day to 8 weeks old, 140 individuals) were surveyed for the three immunologically distinct fimbrial adhesins FY, 31A, and K99. Of a total of 1,370 strains isolated, 96 (7.0%), 34 (2.5%), 75 (5.5%), and 13 (0.9%) were identified as FY+, 31A+, FY+.31A+, and K99+, respectively. The K99+ strains also manifested heat-stable enterotoxin production (ST+), while FY+, 31A+, and FY+.31A+ strains were ST-. Expression of FY and 31A was repressed at lower temperatures or poor aeration. The FY+ and 31A+ E. coli showed mannose-resistant hemagglutinating activity with bovine erythrocytes. Electron microscopy revealed that FY is a gently curled fimbria with a mean diameter of 4.2 nm, and 31A is a fimbria with a mean diameter of 5.1 nm. The molecular mass of protein subunits was found to be approximately 20 kilodaltons (Kd) and 19 Kd for FY and 31A, respectively. Lethal diarrhea of neonatal calves was induced by challenge with the combination of a K99+.ST+ E. coli strain and either a 31A+ E. coli strain or a 31A+ E. coli strain plus an FY+ E. coli strain under the experimental conditions in which lethal diarrhea was not induced by challenge with a K99+.ST+ E. coli strain alone.

Adhesins, Escherichia coli↗
PubMed1987

[Development of an animal model of autonomic over-activity in tetanus].

Although present day progressive respiratory management has decreased the tetanus mortality rate, tetanus-related autonomic overactivity remains a lethal condition. The cause, pathophysiology, and treatment of this condition are controversial and no animal model has ever been reported. So we tried to make a rabbit model of this condition. At first we injected 30 micrograms of purified tetanus toxin intravenously. Blood pressure oscillation occurred, but the degree of oscillation was smaller than that was seen in the clinical cases. The degree of oscillation had not changed by addition of 30 micrograms purified toxin 12 hours after first injection. Secondly, 7 days before the experiment we injected 0.5 micrograms of purified tetanus toxin intravenously. On the experiment day, we injected 30 micrograms of purified toxin again. By this method there occurred blood pressure oscillation as same as that was seen in the clinical cases. But no rabbits progressed to circulatory collapse by purified toxin. Then to the last group of rabbits, we injected crude tetanus toxin for purified toxin. The degree of blood pressure oscillation was same as that of cases in which purified toxin was injected, and all rabbits progressed to circulatory collapse.

Animals↗
PubMed1986

Prolonged hemodynamic maintenance by the combined administration of vasopressin and epinephrine in brain death: a clinical study.

The present study attempted long term hemodynamic maintenance in 16 adult brain-dead patients, 14 with head injury and 2 with cerebrovascular accidents. In addition to respiratory and fluid management, 10 were treated with continuous infusion of epinephrine to maintain systolic blood pressure above 90 mm Hg. The remaining 6 patients each received a continuous infusion of synthetic arginine vasopressin (ADH) at a rate of 1 or 2 units/hour (285 +/- 45 microunits/kg/minute) simultaneously with epinephrine. The 10 patients treated with epinephrine alone all succumbed to cardiac arrest within 48 hours of brain death, with a mean survival time of 24.1 +/- 17.2 hours. In the patients who received simultaneous ADH infusion, a minimal dose of epinephrine of no more than 0.5 mg/hr in most instances sufficed to maintain blood pressure. Their mean survival time after brain death was remarkably prolonged to 23.1 +/- 19.1 days. In brain death, ADH plays a critical role in hemodynamic maintenance, and ADH administration permits long term hemodynamic stabilization of brain-death patients, offering increasing opportunities for organ transplantation.

Adolescent↗
PubMed1986

Inhibition of IA positive reticulum cell sarcoma tumor cell growth in syngeneic SJL/J mice by passive administration of monoclonal anti-IA antibody.

SJL/J (H-2s) mice develop spontaneous reticulum cell sarcoma (RCS) tumors at the age of 8-11 months. The RCS tumor expresses IA antigens on the cell surface, stimulates syngeneic T-cell proliferation, and appears to depend on host cells' participation for its own growth. The present study investigates the role of passively administered monoclonal anti-IA antibody on RCS tumor growth. The administration of monoclonal anti-IAs antibody into SJL/J mice prior to tumor inoculation or at the same time as tumor transplantation resulted in a significant inhibition of tumor growth. Furthermore, pretreatment of RCS tumor with antibody prior to inoculation also resulted in tumor growth inhibition. The inhibition seen in all cases studied was tumor specific, since the use of normal ascites on antibody directed against unrelated antigens resulted in no inhibition of tumor growth. Examination of tumor cells derived from spleen and lymph nodes of antibody treated mice demonstrated that the observed inhibition of tumor growth was the result of a significant depletion of IA positive tumor cells. In contrast to other tumor systems studied to date whereby anti-IA antibody promotes tumor growth, the present findings demonstrate that passive administration of anti-IA antibodies inhibit RCS tumor growth in syngeneic mice. The possible mechanisms involved are discussed.

Animals↗
PubMed1985

Inhibition by adenine of in vitro immunological functions of normal and adenine phosphoribosyltransferase-deficient human lymphocytes.

Exogenous adenine strongly inhibited mitogen-stimulated transformation, cytoplasmic immunoglobulin production, and natural killer activity of human mononuclear leukocytes at the high concentration of 1.0 mM. These inhibitions by adenine were not due to cytotoxicity, because the viability of cultured cells was not affected by adenine up to 1.0 mM. As the magnitude of inhibition by adenine of these in vitro immunological functions was similar in normal and adenine phosphoribosyltransferase-deficient cells, its inhibition was not mediated by corresponding nucleotides. Adenine at the concentration of 0.1 mM caused 50% inhibition of cytoplasmic immunoglobulin production without alternating cell proliferation or viability. This suggests that an appropriate concentration of adenine may inhibit the differentiation of B cells to plasma cells rather than affecting cell proliferation. Understanding the mechanisms of adenine inhibition may lead to new approaches for the regulation of immune responses.

Adenine↗
PubMed1985

Natural killer activity in two cases of ataxia telangiectasia.

We report two cases of ataxia telangiectasia in which a small number of T cells and a slightly diminished response to phytohaemagglutinin or concanavalin A were observed. In one case, serum IgA was undetectable. In spite of T and/or B cell involvement, natural killer activity and the percentage of natural killer cells determined by monoclonal antibodies Leu 7 were normal in both cases.

Adolescent↗