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Biomedical subjects

T Nishinaka

Publications and source records attributed to T Nishinaka.

At least 55 records · Page 3Linked to original sources
PubMed1995

Development of an autoflow cruise control system for a centrifugal pump.

To improve the ease of driving a centrifugal pump that is afterload dependent, we have developed an automatic flow control system for the Terumo Capiox centrifugal pump system. This system consists of an autoflow cruise control system with a safety cutoff. The Capiox Pump Console 3000 was controlled by a personal computer through a serial communication line. In the usual manual mode, the motor speed knob works as a pump speed control, and in the autoflow mode, the same knob works as a blood flow rate control. After selecting and obtaining the desired flow rate, the mode was changed from manual to autoflow mode. In the autoflow mode, the computer compares the desired flow rate with the actual flow measured by an ultrasonic Doppler flowmeter and adjusts the motor rotational speed accordingly. During both in vivo and in vitro testing, this autoflow mode was able to return the changed flow that was disrupted by either clamping and declamping of the tubing or by the bolus injection of a vasomotor drug to the selected flow rate within 10 s without any significant fluctuation. In conclusion, the newly developed computer controlled autoflow system was able to produce a reliable and effective flow regulation for a centrifugal pump.

Animals↗
PubMed1995

Modulation of subcellular particles of the rat small intestine and liver by ebselen.

Reactions between ebselen and subcellular particles of rat liver were investigated by monitoring the activity of mitochondrial glutamate dehydrogenase and microsomal glucose 6-phosphate dehydrogenase. Rat small intestine lactate dehydrogenase was purified and was also used in the reaction between cytosolic protein and ebselen. Glutamate dehydrogenase in intact rat liver mitochondria was completely resistant to ebselen, but the enzyme was significantly inactivated in broken mitochondria mediated by Triton X-100, reflecting the fact that ebselen was not transported through the mitochondrial membrane into the matrix. Glucose 6-phosphate dehydrogenase in rat liver microsomes was inactivated by ebselen, accompanied by a slight decrease in the thiol groups of microsomal membrane protein. Purified cytosolic lactate dehydrogenase was inactivated concentration- and time-dependent by ebselen. The activity of rat small intestine lactate dehydrogenase abolished by ebselen was significantly restored by incubation with purified rat small intestine thioltransferase in the presence of reduced glutathione (GSH). The level of thiol groups in rat liver microsome membrane protein decreased by ebselen was partially restored by an incubation with purified rat liver thioltransferase in the presence of GSH. The results suggested that thioltransferase can cleave the Se-S conjugates between ebselen and cytosolic proteins or microsomal membrane proteins in the presence of GSH.

Animals↗
PubMed1994

Less platelet damage in the curved vane centrifugal pump: a comparative study with the roller pump in open heart surgery.

The centrifugal pump with the curved vane (Lifestream Centrifugal Pump [LCP]) was applied to cardiopulmonary bypass (CPB) in 10 patients who underwent elective coronary artery bypass grafting. Serum hemoglobin levels, platelet counts, and serum beta-thromboglogulin (beta-TG) levels were measured during CPB. The results were compared with those for a comparative roller pump (RP) group (n = 10). There was no difference in CPB time between LCP (112 +/- 22 min) and RP (121 +/- 22 min) groups. Serum beta-TG levels (ng/ml) were lower in the LCP group than in the RP group (34 +/- 9 vs. 101 +/- 80, 5 min; 81 +/- 33 vs. 236 +/- 112, 30 min; 120 +/- 53 vs. 314 +/- 100, 60 min after initiation of CPB; p < 0.05). There were no significant differences in hemolysis and platelet depletion. The LCP showed excellent hemodynamic performance with less blood trauma in clinical application to open heart surgery.

Cardiopulmonary Bypass↗
PubMed1994

The retinoblastoma gene product RB stimulates Sp1-mediated transcription by liberating Sp1 from a negative regulator.

Studies have demonstrated that the retinoblastoma susceptibility gene product, RB, can either positively or negatively regulate expression of several genes through cis-acting elements in a cell-type-dependent manner. The nucleotide sequence of the retinoblastoma control element (RCE) motif, GCCACC or CCACCC, and the Sp1 consensus binding sequence, CCGCCC, can confer equal responsiveness to RB. Here, we report that RB activates transcription of the c-jun gene through the Sp1-binding site within the c-jun promoter. Preincubation of crude nuclear extracts with monoclonal antibodies to RB results in reduction of Sp1 complexes in a mobility shift assay, while addition of recombinant RB in mobility shift assay mixtures with CCL64 cell extracts leads to an enhancement of DNA-binding activity of SP1. These results suggest that RB is directly or indirectly involved in Sp1-DNA binding activity. A mechanism by which RB regulates transactivation is indicated by our detection of a heat-labile and protease-sensitive Sp1 negative regulator(s) (Sp1-I) that specifically inhibits Sp1 binding to a c-jun Sp1 site. This inhibition is reversed by addition of recombinant RB proteins, suggesting that RB stimulates Sp1-mediated transactivation by liberating Sp1 from Sp1-I. Additional evidence for Sp1-I involvement in Sp1-mediated transactivation was demonstrated by cotransfection of RB, GAL4-Sp1, and a GAL4-responsive template into CV-1 cells. Finally, we have identified Sp1-I, a approximately 20-kDa protein(s) that inhibits the Sp1 complexes from binding to DNA and that is also an RB-associated protein. These findings provide evidence for a functional link between two distinct classes of oncoproteins, RB and c-Jun, that are involved in the control of cell growth, and also define a novel mechanism for the regulation of c-jun expression.

3T3 Cells↗
PubMed1994

[Preservation of fresh homograft using TC199 solution in rat].

The surgical replacement of human vessels using fresh allografts (homograft) has been reported as useful means. Nevertheless, little is known about preservation effect and immunological consequences using TC199 solution. In this study, defined inbred strains of rats were used. The aorta was extracted from Buffalo rats and preserved for 1, 2, and 3 weeks in TC199 solution at 4 degrees C. The preserved graft was then implanted into the Buffalo rats heterotopically, in the abdominal aorta, in the autotransplant group (AUTO) and into the Lewis rat in the allotransplant group (ALLO). The graft patency and histology including immunohistochemical stain (IgG, IgM, and C3 complement) were assessed at 2 weeks after transplantation. In AUTO, the patency was 100% with grafts 1 and 2 weeks' preservation, and 80% with 3 weeks' preservation. In the ALLO, patency was 100% with grafts with one week's preservation, 80% in those with 2 weeks' preservation and 0% those with in 3 weeks' preservation. Histology revealed that fibroblasts and endothelial cells were significantly deteriorated in 3 weeks' preservation in auto transplantation, however, they were well-maintained in 2 weeks' preservation. In the allo-transplantation group, histological deterioration began after 2 weeks preservation. Immunohistochemical staining showed significant deposits of IgG, IgM and C3 in ALLO. Significant infiltration of antibodies was seen in deteriorated tissue due to prolongation of the preservation periods. These results suggested that freshly preserved allograft was antigenic and 2 weeks preservation using TC199 solution was possible in the rat model.

Animals↗
PubMed1993

Modulation of glutathione S-transferase activity by a thiol/disulfide exchange reaction and involvement of thioltransferase.

Low concentrations of cystamine and cystine inactivated human placenta glutathione S-transferase (GST-pi) in cytosolic fraction very effectively, as did the purified enzyme, through the thiol/disulfide exchange reaction. Mixed disulfide formation of GST-pi in cytosol was prevented by thioltransferase existing in cytosol with a low concentration of GSH. This protection of GST-pi activity was more effective with the participation of glutathione reductase. The incorporation of half-[14C]cystine into a GST-pi molecule according to the inactivation was provided by autoradiography. Purified human placenta thioltransferase (1900-fold from cytosol) could release the incorporated half-[14C]cystine from a GST-pi molecule with restoration of enzyme activity. Thioredoxin in placenta cytosol could not protect the GST-pi activity from inactivation at all.

Chromatography, Affinity↗
PubMed1993

Difference in glutathione S-transferase response to oxidative stress between porcine and bovine lens.

Porcine and bovine lens GSTs were compared in the stability against various oxidative stress which is a major factor of cataract formation in order to clarify the role of lens glutathione S-transferase (GST) and its relation to cataractogenesis. Class pi porcine lens GST was inactivated reversibly by biological disulfides, cystine and cystamine, and also inactivated by active oxygen species such as O2- generated through xanthine-xanthine oxidase system and H2O2. On the other hand, class mu bovine lens GST was insensitive to such applied oxidative stress. Furthermore, 1,2-naphthoquinone, which is a metabolite of naphthalene and an actual inducer of naphthalene cataract, strongly inactivated porcine lens GST though it did not affect bovine enzyme. Thus, porcine and bovine lens GSTs had different sensitivity to various oxidative stress which could induce cataract formation. The results suggest that the differential expression of GST isozymes among animals may explain the variation in the cataract formation caused by oxidative stress.

Animals↗
PubMed1993

Anti-ganglioside GD1a monoclonal antibody recognizes senile plaques in the brains of patients with Alzheimer-type dementia.

Immunohistochemical staining of brain tissues from patients with Alzheimer-type dementia (ATD) with an anti-GD1a ganglioside monoclonal antibody is described. This monoclonal antibody labeled some myelinated nerve fibers in brain tissue from a non-demented control subject, in which the staining was distributed preferentially in the cerebral white matter. In brain tissue from ATD patients, some senile plaques (SPs) were also immunostained, with the strongest staining in the hippocampal subiculum, where most of the SPs appeared as clusters of dots. When the immunohistochemical staining was compared with a methenamine silver stain (MS stain), these immunopositive dots were found to be argyrophilic dystrophic (or degenerating) neurites. No amyloid deposits, neurofibrillary tangles (NFTs) or neuropil threads were immunostained. In this study, we used sections cut from formaldehyde-fixed brain samples with a cryostat and pretreatment of the sections with chloroform was essential to obtain positive immunostaining. Gangliosides have been demonstrated to possess some neurotrophic activity and to be localized on cell surface membranes. The localization of the GD1a ganglioside observed in dystrophic neurites suggests that such neurites accumulate a membranous component. In addition, the accumulation of the GD1a ganglioside in SPs suggests it may contribute to SP formation.

Aged↗
PubMed1993

Comparison of purified lens glutathione S-transferase isozymes from rabbit with other species.

Two glutathione S-transferase (GST) isozymes, GST-rl1 and GST-rl2, were purified from rabbit lenses and their properties were compared with those of other animals. GST-rl1 and GST-rl2 are dimeric enzymes whose subunit sizes are 24,000 and 21,500, respectively. The substrate specificities and inhibitor sensitivities of GST-rl1 and GST-rl2 are different from each other and from those of the isozymes from other animals. GST-rl1 immunologically crossreacted with the antibody against class mu GST (rat GST Yb1-Yb1), and GST-rl2 crossreacted with the antibody against class pi GST (rat GST Yp-Yp). N-Terminal amino acid sequences of GST-rl1 and GST-rl2 have great homology with other class mu and class pi enzymes, and thus indicate that they belong to class mu and class pi, respectively. Class pi GST-rl2 is inactivated by 1,2-naphthoquinone, an oxidized metabolite of naphthalene, but class mu GST-rl1 is insensitive to it. These results are similar to those of class pi pig lens GST and class mu bovine lens GST. Thus, the expression pattern of GST isozymes in lens varies with animal species, and may relate to their variation in sensitivity to oxidative stress.

Amino Acid Sequence↗
PubMed1993

Modulation of 3 alpha-hydroxysteroid dehydrogenase activity by the redox state of glutathione.

3 alpha-Hydroxysteroid dehydrogenase (EC 1.1.1.50), purified to homogeneity from rat liver, was strongly inactivated by incubation with a disulfide such as GSSG, L-cystine or L-cystamine, as well as an SH-reagent such as DTNB (5,5'-dithiobis(2-nitrobenzoic acid)), NEM (N-ethylmaleimide) or iodoacetic acid. The inactivation advanced with incubation time. Coenzyme (NADP+) completely protected the enzyme from this inactivation by disulfides, but neither of the substrates (androsterone and benzenedihydrodiol) did. The activity of inactivated enzyme was restored by treatment with thiols such as DTT (dithiothreitol) or GSH. In the GSH/GSSG redox buffer, the enzyme existed in an equilibrium between active (reduced) and inactive (oxidized) forms.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

[Aortic regurgitation developed seven years after mediastinal radiation therapy: report of a case].

We report on radiation-induced valvular dysfunction in a 41-year-old woman who developed aortic regurgitation with clinical symptoms, requiring aortic valve replacement seven years after mediastinal radiation therapy for carcinoma of the breast. She was treated with cobalt radiation therapy of 4000 rads to her left mediastinum. The excised three-cuspid aortic valve was edematous and densely fibrotic without commissural fusion. Histological examination strongly suggested that the aortic valve with diffuse fibrosis, destruction of elastic fibers and bizarre nucleus in fibroblasts had been induced by mediastinal radiation therapy. To our knowledge, symptomatic radiation-induced valvular dysfunction in the aortic position has been reported infrequently, with only eleven reported cases. In this case, symptomatic aortic regurgitation was diagnosed seven years after mediastinal radiation therapy. It is emphasized that long-term follow-up is important for patients receiving mediastinal radiation therapy.

Adult↗
PubMed1993

[A new device: a fenestrated sheath for IABP, which reduces the incidence of ischemia in the lower limbs].

To decrease the incidence of ischemia in the lower limbs, we developed a new introducer sheath for IABP, which had 38 side holes (diameter; 1mm). Forty-five patients who received IABP counterpulsation support with this fenestrated sheath were compared with 108 patients in whom the ordinary nonfenestrated sheath was used. There was no significant statistical difference between these two study groups regarding age, height, weight and IABP insertion time. The frequency of ischemic episode of the lower limbs was 2.2% (one out of 45 patients) in the group with the fenestrated sheath, which was significantly lower than those with the ordinary sheath (18 out of 108: 16.7%) (p < 0.005). From these data, we deduced that this fenestrated sheath allowed more blood flow to the lower limb and was thus effective in preventing limb ischemia, particularly in patients with small caliber femoral arteries.

Aged↗
PubMed1992

Characterization of bovine liver cytosolic 3 alpha-hydroxysteroid dehydrogenase and its aldo-keto reductase activity.

1. 3 alpha-Hydroxysteroid dehydrogenase was purified to homogeneity from bovine cytosolic fraction, which was monomeric and its molecular weight was estimated to be about 35 kDa. 2. The enzyme had ability to catalyze NADP(H)-dependent oxidoreduction of position 3 alpha-hydroxy and keto group of steroids and also could catalyze the reduction of some ketones and quinones. 3. In addition, benzenedihydrodiol was one of the substrates of dehydrogenase activity with NADP+. 4. Indomethacin, synthetic steroids and SH-reagents were potent inhibitors for this enzyme. 5. Inactivation of the enzyme by GSSG-treatment was restored to its original activity by the addition of DTT. 6. The presence of coenzyme, 0.33 mM NADP+, completely protected from the DTNB-inactivation. 7. Bovine liver cytosolic enzyme immunologically crossreacted with rat liver 3 alpha-hydroxysteroid dehydrogenase.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Purification and characterization of glutathione S-transferase isozymes in dog lens.

1. Two isozymes of glutathione S-transferase (GST-dl1 and GST-dl2) were purified to homogeneity from dog lens. 2. The subunit size and the isoelectric point were determined to be 24,000 and > pI 9.5 for GST-dl1 and 22,000 and pI 8.1 for GST-dl2. 3. It was judged that GST-dl1 is a class alpha enzyme and GST-dl2 belongs to class pi on the basis of their immunological properties and N-terminal amino acid sequences. 4. The expression pattern of glutathione S-transferase isoenzymes in dog lens is different from that in pig, rat and bovine lenses.

Amino Acid Sequence↗
PubMed1992

A novel dihydrodiol dehydrogenase in bovine liver cytosol: purification and characterization of multiple forms of dihydrodiol dehydrogenase.

Three enzymes (DD1, DD2, and DD3) having dihydrodiol dehydrogenase activity were purified to homogeneity from bovine cytosol. DD1 and DD2 were identified as 3 alpha-hydroxysteroid dehydrogenase and high-Km aldehyde reductase, respectively, as judged from their molecular weights, substrate specificities and inhibitor sensitivities. DD3 was a unique enzyme which could specifically catalyze the dehydrogenation of trans-benzenedihydrodiol and trans-naphthalenedihydrodiol without any activity toward the other tested alcohols, aldehydes, ketones, and quinones. The Km value of DD3 (0.18 mM) for benzenedihydrodiol was lower than those of other dihydrodiol dehydrogenases so far reported. DD3 immunologically crossreacted with DD1, but showed no crossreactivity with DD2. Additionally, DD3 was inhibited in a competitive manner, with a low Ki value of 1 microM, by androsterone, which was a good substrate for DD1. It was assumed that DD3 is a novel enzyme which is specific to dihydrodiols, exhibiting similarity to DD1 in immunological and structural properties.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Characterization of multiple forms of carbonyl reductase from chicken liver.

Three enzyme forms (CR1, CR2 and CR3) of carbonyl reductase were purified from chicken liver with using 4-benzoylpyridine as a substrate. CR1 was a dimeric enzyme composed of two identical 25-kD subunits. CR2 and CR3 were monomeric enzymes whose molecular weights were both 32 kD. CR1 exhibited 17 beta-hydroxysteroid dehydrogenase activity as well as carbonyl reductase activity in the presence of both NADP(H) and NAD(H). CR2 and CR3 had similar properties with regard to substrate specificity and inhibitor sensitivity. They could exhibit the activity only with NADPH and had no hydroxysteroid dehydrogenase activity. CR2 and CR3 cross-reacted with anti-chicken kidney carbonyl reductase antibody, though CR1 did not. The results suggest that CR1 is a hydroxysteroid dehydrogenase, and CR2 and CR3 are similar to each other and to the kidney enzymes.

17-Hydroxysteroid Dehydrogenases↗