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Biomedical subjects

K Seki

Publications and source records attributed to K Seki.

At least 307 records · Page 17Linked to original sources
PubMed1991

Calcium-regulating hormones and osteocalcin levels during pregnancy: a longitudinal study.

We measured serum concentrations of calcium-regulating hormones and osteocalcin in 20 women longitudinally throughout pregnancy, 1,25-Dihydroxyvitamin D levels were high early in pregnancy and increased with advancing gestation. Parathyroid hormone and osteocalcin levels were low in early pregnancy. They declined toward the middle of pregnancy, but increased in late pregnancy. The serum osteocalcin level correlated with the parathyroid hormone level. The synthesis of osteocalcin by osteoblasts is stimulated by the action of 1,25-dihydroxyvitamin D, and serum osteocalcin levels are also related to the levels of parathyroid hormone. During early and mid pregnancy, the stimulatory effect of 1,25-dihydroxyvitamin D on the synthesis of osteocalcin may be overridden by the inhibitory effect of declining parathyroid hormone levels. The increase in osteocalcin level in late pregnancy may be a consequence of increasing levels of both parathyroid hormone and 1,25-dihydroxyvitamin D.

Adult↗
PubMed1991

The transient appearance of small blastoid cells in the marrow after bone marrow transplantation.

Of 14 patients who underwent allogeneic or syngeneic bone marrow transplantation, 6 had a transient appearance of small blastoid cells in the bone marrow after transplantation. Most of these patients (11) had leukemia, although 3 had severe aplastic anemia. The cells were 8-18 micron in diameter and had scant cytoplasm and dense nuclei with smooth, homogeneous chromatin. They often had distinct nuclear clefts. These cells constituted 4.0-21.3% of the total number of bone marrow cells. They were not reactive with peroxidase, alpha-naphtyl butylate esterase, naphthol AS-D chloroacetate esterase, or periodic acid-Schiff stains. Immunocytochemical analysis revealed that the small blastoid cells expressed terminal deoxynucleotidyl transferase, Ia-like, CD19, and CD10 antigens and cytoplasmic mu heavy chains, indicating a precursor B-cell phenotype. CD20 antigen was not expressed on these cells. The data suggest that cytoplasmic mu may be expressed earlier than CD20 antigen in the differentiation of B-cell lineage. The morphologic, cytochemical, and immunophenotypic characteristics did not distinguish these nonneoplastic cells distinctly from leukemic lymphoblastic cells. The increase of small blastoid cells was a transient and self-limited phenomenon, in contrast to that of neoplastic blasts. These cells should be recognized as a common component of the bone marrow of marrow transplant recipients. The significance and role of these cells in immune recovery and hematopoiesis remain uncertain.

Bone Marrow↗
PubMed1991

The adhesion of protein A-bearing Staphylococcus aureus organisms to soluble-staphylococcal-antigens-coated HeLa cells mediated by specific antibodies.

The adhesion of staphylococcal protein A (SpA)-bearing Staphylococcus aureus Cowan I organisms to HeLa cells was enhanced by pretreatment of HeLa cells with staphylococcal extracellular antigens and antibodies to them. The adhesion of HLj, an SpA-poor mutant derived from Cowan I, to HeLa cells was not enhanced by the same pretreatment of HeLa cells. Furthermore, the enhanced staphylococcal adhesion was inhibited by soluble SpA. The antigen(s) responsible for the enhanced staphylococcal adhesion was(were) heat stable. Pretreatment of HeLa cells with the mixture of staphylococcal extracellular antigens and antibodies to them also enhanced the adhesion of Cowan I. Similarly the adhesion of Cowan I was enhanced by pretreatment of HeLa cells with extracellular antigens of Pseudomonas aeruginosa and antibodies to them. These results indicated that cell-bound SpA mediated the binding of S. aureus to immune complexes composed of extracellular bacterial products and antibodies to them bound to the surface of HeLa cells, and suggested another role of cell-bound SpA as a co-adhesin with other factors in infections due to S. aureus.

Antibodies, Bacterial↗
PubMed1991

Levels of glucose and insulin during twenty-four hours in hyperprolactinemic women with pituitary microadenoma.

Excursions of plasma glucose and insulin throughout the 24-hour metabolic clock were evaluated in hyperprolactinemic women with pituitary microadenoma. The glucose response to food intake and 24-hour excursion of plasma glucose were not altered in hyperprolactinemic women compared to normal women. Premeal and 24-hour insulin levels were significantly increased in hyperprolactinemic women, though fasting insulin levels were not. Postprandial insulin increments appeared to be more sustained in these patients compared to normal women, though the difference was not statistically significant. And therefore the increased 24-hour concentration of insulin in hyperprolactinemic women appears to be due to the sustained insulin response to meals and increased premeal insulin levels. A slight resistance to insulin was observed in hyperprolactinemic women. That the 24-hour excursion of plasma glucose is not altered in hyperprolactinemic women in the face of decreased sensitivity to insulin may be accounted for by the increased insulin secretion.

Adult↗
PubMed1991

Characteristics of blood flow velocity patterns of central systemic veins in healthy adults assessed by Doppler echocardiography.

To evaluate the differences in shape and phase lag of the flow velocity curves in the superior (SVC) and inferior (IVC) venae cavae and the hepatic vein (HV), Doppler echocardiographic examination was performed in 40 healthy adults (aged 20 to 67 years, mean +/- SD: 39 +/- 12 years). Flow velocity patterns in each vein were characterized by 4 major deflections: S wave, a systolic forward flow; D wave, a diastolic forward flow; A wave, a small backward flow or reduction of diastolic forward flow due to atrial contraction; and O wave, a small backward flow or reduction of forward flow after the second heart sound. Except for a reduced phasic flow in a collapsed IVC, the venous flow velocity recordings in each vein demonstrated very similar pulsatile patterns and small differences in mean time lags of less than 50 msec. In general, the lowest values of peak A/peak S, peak O/peak S and peak D/peak S were observed in HV flow and the highest in IVC flow. Backflows of A and O waves were prominent in HV flow, but small and least frequent in IVC flow. These data suggest that the baseline of the central venous flow recordings might shift downward in HV flow and upward in IVC flow. However, even if both the baseline shift and amplitude of the flow curve were normalized in each venous flow velocity curve, apparent differences in shape of the flow velocity curves would remain. We concluded that the characteristics and differences of each central venous flow velocity pattern should be noted in studies of these areas.

Adult↗
PubMed1991

Biochemical and functional analysis of mixed isotype A beta E alpha class II molecules in Ed alpha transgenic mice.

We demonstrated the existence of mixed isotype A beta E alpha class II molecules in Ed alpha gene-introduced C57BL/6 (B6Ed alpha) transgenic mice. Immunoprecipitation and two dimensional (NEPHGE/SDS-PAGE) gel electrophoresis analysis of labeled B6Ed alpha spleen cell lysates using monoclonal anti-Ab beta antibody showed Ed alpha spots in addition to Ab beta and Ab alpha spots. We obtained alloreactive T cell clones from B6 anti-B6Ed alpha long-term cultures that recognized the Ab beta Ed alpha molecule. We also obtained antigen reactive T cell clones that recognized antigen in the context of Ad beta Ed alpha mixed isotype class II molecules. The importance of the mixed isotype class II molecules in relation to the expansion of the T cell specificity repertoire as well as autoimmune induction is discussed.

Animals↗
PubMed1991

[Studies on EDTA-dependent pseudoneutropenia].

The phenomenon of EDTA-dependent pseudoleukocytopenia was observed in seven patients during the period from September 1989 to March 1990. The pseudoleukocytopenia was found to have come from aggregation of neutrophils. The aggregations were composed of neutrophils only, and did not include other granulocytes, monocytes and lymphocytes. The aggregations showed their maximum in size from 30 to 180 minutes after venipuncture at room temperature. The aggregated neutrophils were again dispersed by incubating at 37 degrees C for 30 minutes. The degree of aggregation was found to be dependent on the concentration of EDTA. Neutrophil aggregation was not recognized in the blood films when sodium citrate or heparin was used as an anticoagulant. The results of mercaptoethanol agglutination test and immunocytochemical staining suggest that IgM antibody may play an important role in the formation of neutrophil aggregation. Four of the seven patients had suffered from hepatic disorder. However, the mechanism of EDTA-dependent neutrophil aggregation remains uncertain.

Adult↗
PubMed1991

[Coronary artery spasm after aortic valve replacement: a case report].

A 64-year-old man who had aortic valve regurgitation underwent aortic valve replacement. There had been no history of angina pectoris or taking of calcium channel blockers. When the operation was nearly completed, unexpected hemodynamic collapse happened without ST-segment changes on the ECG monitoring. Resuscitation was successful by cardiac massage, pacing and administration of catecholamine. Thereafter the same episodes occurred several times. At the 6th attack on postoperative day 7, we confirmed the ST-segment elevation using 12-lead-ECG, thus coronary artery spasm was diagnosed. Thereafter calcium channel blocker and coronary vasodilator were administered continuously. There has been no attack since postoperative day 13. Though postoperative coronary arteriography showed no anatomical changes compared with preoperative study, direct injection of ergonovine made the right coronary artery spastic, but not the left. We emphasized that perioperative coronary artery spasm may happen not only in the coronary artery surgery but in any other cardiac operations.

Aortic Valve↗
PubMed1991

[Intracardiac repair in left ventricular rupture following mitral valve replacement].

Rupture of the left ventricle is one of the major lethal complications of mitral valve replacement. We have encountered 11 cases of this complication over a period of 19 years (1971, Apr.-1990, Mar.). Five of 8 cases of intraoperative rupture survived but no patient survived a delayed rupture. In the patients with intraoperative rupture external repair was performed in 6 cases, resulting in 3 survivors, two in type II and one in type I with formation of left ventricular false aneurysm. For selection of surgical treatment accurate recognition of types of rupture is important but the location and size of the endocardial and epicardial defects do not always correspond. Attempts to suture a ventricular rupture on the pressure-loaded beating heart were always unsuccessful and frequently extended the tear. Repair should be accomplished with aid of cardiopulmonary bypass on the decompressed and arrested heart. Recently, we chose internal repair with arrested heart in 2 cases of type I rupture, that is, reopening of the left atrial closure and repair from within the cardiac chamber with removal of the prosthetic valve. Both cases survived. In conclusion, we emphasized importance of intracardiac repair with removal of the replaced prosthetic valve in left ventricular rupture of type I and III following mitral valve replacement for better exposure, more secure repair, and prevention of injury to the circumflex artery.

Adult↗
PubMed1990

Antigen-reactive T cell clones restricted by mixed isotype A beta d/E alpha d class II molecules.

Mixed isotype A beta dE alpha d class II molecule-restricted antigen-reactive T cell clones were obtained from (BALB/c x B6E alpha d)F1 mice. These T cell clones responded to keyhole limpet hemocyanin in the presence of (BALB/c x B6E alpha d)F1 but not CBF1 APCs. Both anti-A beta d and anti-E alpha mAbs blocked the proliferative responses of these clones. The frequency of such mixed isotype A beta E alpha-restricted T cell clones in (BALB/c x B6E alpha d)F1 mice was estimated to be approximately 10% from our limiting dilution cloning. The existence of such mixed isotype class II molecule-restricted T cells would have important implications for the expansion of the T cell repertoire as well as the induction of autoimmunity.

Animals↗