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Biomedical subjects

K Sakai

Publications and source records attributed to K Sakai.

At least 523 records · Page 29Linked to original sources
PubMed1996

Attenuation of the no-reflow phenomenon after coronary angioplasty for acute myocardial infarction with intracoronary papaverine.

The no-reflow phenomenon is observed as reduction of coronary blood flow on the angiograms (angiographic no-reflow) after immediate percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI). To assess whether a potent coronary microvascular dilator--papaverine--could attenuate the no-reflow phenomenon, nine patients with AMI who were found to have angiographic no-reflow after PTCA were studied. Angiographic no-reflow was defined as the Thrombolysis in Myocardial Infarction flow grade 1 or 2 without any mechanical obstructions in the epicardial artery. A bolus dose of 10 mg of intracoronary papaverine was administered, and the flow grade was again evaluated. Intracoronary papaverine caused a significant improvement of the flow grade (p= 0.0152). The number of cineframes that were required for the contrast medium to pass two selected landmarks on the angiograms also significantly decreased (41 +/- 17 frames to 18 +/- 8 frames, p= 0.0039). Thus intracoronary papaverine attenuated angiographic no-reflow that occurred after PTCA for AMI.

Adult↗
PubMed1996

Restoration of sensibility in the hand after complete brachial plexus injury.

Twenty-one patients with complete brachial plexus palsy due to the avulsion of multiple cervical nerve roots underwent motor and sensory reconstruction. Of these, 15 patients who had been followed for at least 2 years were included in the present study. Sensory reconstruction was performed by nerve graft or nerve crossing to the median nerve. The donor nerves included the supraclavicular nerve in 10 patients, the intercostal nerve in 3, and the C5 nerve root in the first 2 patients. Limited sensibility in the median nerve distribution of the hand was restored in 12 patients, and the results were classified as S2+ in 2, S2 in 4, S1 in 6, and S0 in 3, according to the S0 to S4 grading system. No moving two-point discrimination was restored in any case. While the best recovery obtained was only at the S2+ level, even this limited sensibility was useful for otherwise completely anesthetic patients.

Adolescent↗
PubMed1996

The effect of sodium and ultrafiltration modelling on plasma volume changes and haemodynamic stability in intensive care patients receiving haemodialysis for acute renal failure: a prospective, stratified, randomized, cross-over study.

BACKGROUND: Haemodynamic stability in intensive care unit (ICU) patient with acute renal failure (ARF) during intermittent dialytic support has been the focus for several variations to dialysis delivery. Indeed this has been noted by many as a possible cause for prolonged renal dysfunction created by repeated hypotensive renal insult, as well as a reason for the lower delivered dialysis dose afforded. End-stage renal failure patients supported by intermittent dialysis have benefitted from variable sodium dialysate and variable ultrafiltration rate protocols. The current study has focused upon the response to these dialysis variations in the ICU ARF patient. METHODS: Successive ICU patients with defined characteristics of ARF requiring dialytic support were entered into a prospective, stratified (by Cleveland Clinic Foundation ARF Acuity Score), randomized, crossover designed study to evaluate haemodynamic effects and need for interaction during dialysis therapy delivering a fixed dialysis dose based upon area kinetic analysis. Subjects were supported either by a fixed dialysate sodium (140 meq/dl) and fixed ultrafiltration rate (Protocol A), or a variable sodium dialysate (160-140 meq/dl) and variable ultrafiltration (50% UF during the first third of treatment time, 50% UF over the last two thirds treatment time) (Protocol B). After three sessions, the patients were crossed to the other protocol, and if continued, after three sessions returned to the original protocol. Mean arterial pressures, Cardiac output, serum electrolytes, serum albumin, and relative blood volume changes were measured. Frequency of nursing intervention, quantity and type of volume replacements as well as pressor agent use was standardized, documented and compared. RESULTS: Ten ARF patients (age: 64.2 +/- 13.7 years), CCF acuity score (13.3 +/- 3.9), APACHE II score (28.7 +/- 4.7). MAP (VNA: 82.8 +/- 16.9; FNA: 86.2 +/- 18.9 mmHg), CO, cardiac index, pressor support interventions required (VNA: 16%: FNA: 48.4%, P < 0.001), blood volume changes (Critline) (VNA: -6.6 +/- 5.2; FNA: -7.59 +/- 6.7, P < 0.05), S. albumin (VNA: 2.4 +/- 0.6; FNA: 2.81 +/- 0.9 g/dl, ns) pre/post S.Na (VNA: 138.7 +/- 5.1/141.7 +/- 2.3; FNA: 136.6 +/- 5.96/139.1 +/- 3.71 mmol/dl), osmolality, Urea (VNA: 69.5 +/- 0.6; FNA: 70.5 +/- 0.6%, ns) and Creatinine (VNA: 56.6 +/- 0.5: FNA: 59.6 +/- 0.5%, ns) Reduction ratio, dialysis time (VNA: 4.8 +/- 0.5: FNA: 4.6 +/- 0.45 h) and achieved UF (VNA: 2.0 +/- 1.2; FNA: 1.56 +/- 1.3 L, P < 0.05) were measured. CONCLUSION: Haemodynamic stability was greater during Protocol B than during Protocol A in all patients. Significantly less intervention was noted during Protocol B, despite the same dialysis delivery during both Protocols. Relative Blood volume changes were less during Protocol B, despite a greater total ultrafiltration. Variable sodium dialysate coupled with a variable ultrafiltration rate seems to be the preferred dialysis prescription for ICU ARF patients undergoing intermittent haemodialysis.

Acute Kidney Injury↗
PubMed1996

Conformational change precedes the formation of multimeric fibronectin.

Plasma fibronectin incubated with a low concentration of SH reagent under physiological conditions without cells formed a multimer which retained the ability of heparin-binding and cell-binding but lost gelatin affinity [Sakai, K., Fujii, T., and Hayashi, T. (1994) J. Biochem. 115, 415-421]. The conformation of the multimeric fibronectin, as observed by ultraviolet circular dichroism and fluorescence spectroscopy was different from that of dimeric plasma fibronectin. Monitoring the change in ellipticity indicated that conformational change was mostly accomplished within the first 3 h of incubation with 0.5 mM dithiothreitol at 37 degrees C. In contrast, multimers became detectable after 4 h of incubation. The results indicate that the overall reaction of multimerization of plasma fibronectin consists of two steps: the initial step of conformational change of dimeric fibronectin, and the later polymerization step of the polypeptide in an altered conformation. The initial step, involving the conformational change of fibronectin, depended on temperature: it proceeded at 37 degrees C but not at 25 degrees C. In contrast the second step took place at 25 degrees C at a low, yet significant rate. Proteolytic susceptibility of the fibronectin to thermolysin or m-calpain changed within 3 h of incubation with dithiothreitol at 37 degrees C in accordance with the conformational change detected by circular dichroism. Namely, the fibronectin in an altered conformation appeared to be less susceptible to thermolysin, but more susceptible to m-calpain. The changes in enzymatic susceptibilities tended to be localized in the amino- and carboxyl-terminal regions, which are consistent with the implications from the spectroscopic analysis.

Animals↗
PubMed1996

The induction of metachromasia and circular dichroism of coomassie brilliant blue R-250 with collagen and histone H1 is due to the low content of hydrophobic amino acid residues in these proteins.

Collagen and histone H1 are stained a pink-red color with Coomassie Brilliant Blue R-250 (Coomassie R) instead of the blue color of most proteins after SDS-PAGE. Spectrophotometrically, this metachromasia was characterized by an increase in the absorbance at 535 nm and a decrease in the absorbance at 600 nm. The ratio of the absorbance at 535 nm to that at 600 nm ranged from 1.5 to 2.5 for the pink-red-stained proteins and was about 1 for the blue stained proteins. In their amino acid composition, the pink-red-stained proteins collagen and histone H1 contained less than 11% of hydrophobic amino acid residues, whereas the five blue-stained proteins examined contained more than 25% of such residues. Collagen and histone H1 also induce circular dichroism (CD) of Coomassie R in the visible region with a different CD spectrum. In the case of native collagen, a CD (+) band at 530 nm with 10(5) molar ellipticity was observed, while the denatured collagen showed a CD(-) band at 530 nm. When the amino groups of the amino acid residues in collagen and histone H1 were converted into hydrophobic groups by fluorescamine treatment, these proteins stained bluer than pink-red and the induced CD was a lower intensity. This is the first report of the metachromatic interaction between a protein and Coomassie R that is accompanied by CD induction. This report also suggests that the induction of metachromasia and CD of Coomassie R was due to the low content of hydrophobic amino acid residues in the peptides.

Amino Acids↗
PubMed1996

Purification and characterization of a novel isoform of mast cell tryptase from rat tongue.

Rat mast cell tryptase was purified to homogeneity from rat tongue by a series of standard chromatographic procedures. Since the enzyme gave band corresponding to molecular mass of 32-35 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis and exhibited a molecular mass of 135 kDa on gel filtration, it was presumed to be a noncovalently associated tetramer. The N-terminal amino acid sequence of 50 residues of the enzyme showed the highest degree of homology with the same region in mouse mast cell protease 7 (92%), and less homology to those of tryptases from man and dog, and peritoneal cells of rats and Mongolian gerbils. The inhibitor specificity of rat tongue tryptase was similar to that of rat peritoneal mast cell tryptase free from trypstatin: it was inhibited by alpha 1-antitrypsin, Kunitz-type soybean trypsin inhibitor and Bowman-Birk soybean trypsin inhibitor, but these inhibitors do not inhibit the tryptases from rat skin, human lung, and dog mast cells. Judging from these results, together with other enzymatic properties, the enzyme may be a novel isoform of tryptase in rat tongue. Analysis by differential staining with peroxidase-labeled lectins of the enzyme suggested that it has tri- and/or tetraantennary complex-type oligosaccharides containing a relatively high amount of sialic acid. The immunohistochemical distribution of this enzyme indicated that the reactive antigen was specific in connective tissue but not in mucosal mast cells.

Amidohydrolases↗
PubMed1996

Case report: agranulocytosis induced by interferon-alpha therapy for chronic hepatitis C.

A 60-year-old woman presented with chronic active hepatitis C whose HCV-RNA genotype was II according to Okamoto's classification and serum HCV-RNA concentration was 10(4) copies/mL. Agranulocytosis was induced 13 days from the commencement of interferon (IFN)-alpha 2b (6 MU/day) therapy, so the IFN therapy was immediately discontinued. The agranulocytosis improved rapidly with the administration of a granulocyte colony stimulating factor (G-CSF). The possibility that IFN was associated with maturational arrest of myeloid progenitor cells was considered. During the course of 3 years of follow-up, her liver function has remained normal and serum HCV-RNA remains negative.

Agranulocytosis↗
PubMed1996

Comparison of pressure resistances of spores of six bacillus strains with their heat resistances.

The pressure resistances of the spores of six Bacillus strains were examined at 5 to 10(deg)C and were compared with their heat resistances. The pressure treatments (at 981 MPa for 40 min and at 588 MPa for 120 min) did not inactivate the spores of B. stearothermophilus IAM12043, B. subtilis IAM12118, and B. licheniformis IAM13417. However, these spores had large differences in heat resistance. The spores of B. megaterium IAM1166 were 9.3 times more pressure resistant but 246 times less heat resistant than those of B. stearothermophilus IAM11001. The spores of B. coagulans IAM1194 were activated by the pressure treatments. There was no correlation between these pressure and heat resistances.

Journal Article↗
PubMed1996

Degradation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by the white rot fungus Phanerochaete sordida YK-624.

A method for the degradation of dioxins by white rot fungi was developed. Degradation of a mixture of 10 kinds of tetra- to octachlorodibenzo-p-dioxins (polychlorinated dibenzo-p-dioxins [PCDDs]) and tetra- to octachlorodibenzofurans (polychlorinated dibenzofurans [PCDFs]), which were chlorinated at 2-, 3-, 7-, and 8-positions of the molecules, by the white rot fungus Phanerochaete sordida YK-624 was studied in a stationary low-nitrogen medium. The percent degradation values of PCDDs and PCDFs were approximately 40 (tetra-chloro-) to 76% (hexachloro-) and 45 (tetrachloro-) to 70% (hexachloro-), respectively. Metabolites of 2,3,7,8-tetra- and octaCDD formed by P. sordida YK-624 included 4,5-dichlorocatechol and tetrachlorocatechol, respectively. These results suggest that white rot fungus is able to substantially degrade both PCDDs and PCDFs. This is the first report of the degradation of highly chlorinated PCDDs and PCDFs by a microorganism.

Basidiomycota↗
PubMed1996

Bleaching of Hardwood Kraft Pulp with Manganese Peroxidase from Phanerochaete sordida YK-624 without Addition of MnSO(inf4).

In vitro bleaching of an unbleached hardwood kraft pulp was performed with partially purified manganese peroxidase (MnP) from the fungus Phanerochaete sordida YK-624 without the addition of MnSO(inf4) in the presence of oxalate, malonate, or gluconate as manganese chelator. When the pulp was treated without the addition of MnSO(inf4), the pulp brightness increased by about 10 points in the presence of 2 mM oxalate, but the brightness did not significantly increase in the presence of 50 mM malonate, a good manganese chelator. Residual MnP activity decreased faster during the bleaching with MnP without MnSO(inf4) in the presence of malonate than in the presence of oxalate. Oxalate reduced MnO(inf2) which already existed in the pulp or was produced from Mn(sup2+) by oxidation with MnP and thus supplied Mn(sup2+) to the MnP system. The presence of gluconate, produced by the H(inf2)O(inf2)-generating enzyme glucose oxidase, also improved the pulp brightness without the addition of MnSO(inf4), although treatment with gluconate was inferior to that with oxalate with regard to increase of brightness. It can be concluded that bleaching of hardwood kraft pulp with MnP, using manganese originally existing in the pulp, is possible in the presence of oxalate, a good manganese chelator and reducing reagent.

Journal Article↗
PubMed1996

Activation of human presupplementary motor area in learning of sequential procedures: a functional MRI study.

1. Using functional magnetic resonance imaging, we investigated the neural correlates of sequential procedural learning. During the test scans the subjects learned a new sequence (position or color) of button presses; during the control scans they pressed the buttons in any order. The comparison of the test and control scans was expected to reveal the neural activities related to learning, not sensory-motor processes. 2. We found that a localized area in what we regard to be the human homologue of the presupplementary motor area (pre-SMA) was particularly active for learning of new sequential procedures (either position or color sequences), not movements per se. 3. In contrast, the SMA proper (posterior to pre-SMA) was active for the performance of sequential movements, not learning. This was shown in another paradigm in which the subjects pressed the buttons in any order in the test scans and just watched the sequence in the control scans. 4. The learning-related pre-SMA region, which was consistent across different experiments in single subjects, was identified on only one side in each subject.

Humans↗
PubMed1996

Study on proteinase-inhibiting capacity of plasma alpha 2-macroglobulin in idiopathic nephrotic syndrome.

We studied the relationship between plasma alpha 2-macroglobulin (alpha 2M) and depressed cell-mediated immunity in idiopathic nephrotic syndrome (INS). Plasma alpha 2M concentrations (mumol/l) were increased during relapses of INS; however, the proteinase inhibitory activity, measured using bacterial thermolysin, was significantly decreased when calculated per 1 mol of alpha 2M, implying a reduced proteinase-inhibiting capacity of alpha 2M. The decreased proteinase-inhibiting capacity of alpha 2M was associated with the inhibitory activity of plasma on normal lymphocyte blastogenesis. Purified alpha 2M, when complexed with chymotrypsin, intensively inhibited normal lymphocyte blastogenesis induced by concanavalin A, as compared with the free form of alpha 2M. From these results it is suggested that, although the amount of alpha 2M protein has increased in the plasma of INS patients during relapse, its binding capacity to proteinases has relatively decreased. The results of this study may provide speculation for both the well-known high plasma alpha 2M concentrations and the immunodepression, both of which have been observed in INS patients in the past few decades.

Adolescent↗
PubMed1996

The treatment of chronic hemodialysis vascular access by directional atherectomy.

Directional atherectomy (DA) was developed as a new therapeutic modality for coronary artery disease. For the past 3 years, we have applied DA intervention to vascular access failure with either poor blood flow rate or high venous pressure. DA intervention was performed on 27 lesions of 16 hemodialyzed patients. A reduction of stenosis to less than 20% of that before treatment was judged a technical success, and the rate of technical success was 84%. All patients showed adequate blood flow rates after DA intervention, indicating initial success. Although restenotic events occurred frequently, repeated DA interventions could be performed successfully. The patency rate at 1 month after DA intervention was 100%, at 3 months 93%, at 6 months 92% and at 12 months 75%. The short-term patency rate of DA was more satisfactory than the results of percutaneous transluminal angioplasty as reported by several investigators. Regarding the site of stenosis, restenotic events were relatively fewer in the lesions occurring at the native vein compared to those at graft-venous anastomotic sites. Eccentric-type stenosis was also associated with fewer restenotic events than circumferential-type stenosis. These results suggest that eccentric-type stenosis at the native vein is the most suitable lesion for the application of DA intervention in terms of long-term patency. As no severe complications occurred after DA intervention, this would appear to be a useful therapeutic modality for the correction of vascular access failure.

Aged↗
PubMed1996

Regulation of corticotropin-releasing factor receptor messenger ribonucleic acid in rat anterior pituitary.

Adrenalectomy (ADX) leads to a decrease in the number of CRF-binding sites in the rat anterior pituitary (AP). However, the molecular mechanisms of CRF receptor (CRF-R) regulation are unknown. In the present study, we analyzed the effects of ADX on pituitary CRF-R1 messenger RNA (mRNA) levels in vivo and the direct effects of CRF, arginine vasopressin (AVP), and glucocorticoid, the levels of which are altered by ADX, on CRF-R1 mRNA levels in vitro. The mRNA level was determined by Northern blot analysis using a rat brain CRF-R1 complementary RNA probe. The CRF-R1 level in AP fell to 20% of the sham level 1 day after ADX and returned to the sham level after 14 days. In cultured rat AP cells, treatment with CRF, AVP, and dexamethasone led to significant reductions in CRF-R1 mRNA, with maximal inhibition to 32%, 22%, and 37% of control levels, respectively. The time course of CRF-R1 mRNA reduction varied depending on the drug, with effects detectable as early as 1 h after treatment. These findings indicate that elevated portal CRF and AVP levels may contribute to the decrease in CRF-R1 mRNA soon after ADX. A decrease in mRNA levels, in turn, may lead to a decrease in CRF-R1 protein on corticotrophs.

Adrenalectomy↗
PubMed1996

Major role of 3',5'-cyclic adenosine monophosphate-dependent protein kinase A pathway in corticotropin-releasing factor gene expression in the rat hypothalamus in vivo.

To assess whether the cAMP-dependent protein kinase-A and/or the diacylglycerol-dependent protein kinase C (PKC) pathways play important roles in the activation of CRF neurons in vivo under physiological conditions, we tested the effect of microinjection of 8-bromo-cAMP (8-Br-cAMP) or 12-O-tetradecanoyl phorbol 13-acetate (TPA) into both paraventricular nuclei (PVN) of the hypothalamus in conscious rats. Both 8-Br-cAMP and TPA increased plasma ACTH concentrations and the POMC messenger RNA (mRNA) concentrations in the anterior pituitary. While injection of 8-Br-cAMP also increased CRF mRNA concentrations in hypothalamic tissue containing the PVN, TPA injection had no effect on CRF mRNA concentrations there. During insulin-induced hypoglycemia, which stimulates CRF gene expression and release, c-fos and c-jun mRNA increases in the hypothalamic tissue preceded the increase in the CRF mRNA level after insulin-induced hypoglycemia. Antisense oligodeoxyribonucleotides (oligos) directed against c-fos, c-jun, or the cAMP response element binding protein (CREB) mRNA were injected into both PVN before insulin-induced hypoglycemia to assess whether activator protein-1 or CREB mediates transcriptional activation of CRF during hypoglycemia. Only antisense oligo against CREB mRNA reduced the CRF mRNA level after insulin-induced hypoglycemia. These results suggest that protein kinase A may transduce intracellular signals in CRF neurons under physiological conditions and raises the possibility that CREB may be involved in stress-induced CRF gene expression.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

The surface properties of chemically synthesized peptides analogous to human pulmonary surfactant protein SP-C.

A number of peptides with different lengths corresponding to various regions of human pulmonary surfactant protein SP-C were synthesized and their activity evaluated to improve in vitro surface activities and in situ lung pressure-volume characteristics of a ternary lipid mixture composed of dipalmitoylphosphatidylcholine, phosphatidylglycerol and palmitic acid (75:25:10, w/w). SP-C (1-35), a synthetic peptide with the entire length of human SP-C, and some other peptides with various lengths of its partial sequences were remarkably active. All of these peptides shared a common core sequence of (C)CPVHLKRLLIVVVVVVLIVVVIVGAL(L). Any deletion in this core sequence resulted in reduction of activity of the peptide. SP-C (5-31) and SP-C (6-32), the minimum peptides containing the core sequence, were combined with the ternary lipid mixture at the final peptide concentration of 2% (w/w) into synthetic surfactants which showed excellent properties comparable with those of Surfacten, a commercially available modified bovine lung surfactant. In a Langmuir-Wilhelmy surface balance, the synthetic surfactant containing SP-C (6-32) spread and adsorbed quickly to reach a surface tension of 30.8 mN/m at 30-s spreading time and 41.2 mN/m at 1-min adsorption time, respectively; the presence of SP-C (6-32) significantly prevented the decrease of surface activity of the ternary lipid mixture during dynamic compression-expansion cycles. Furthermore, tracheal instillation of the synthetic surfactant containing SP-C (6-32) at the dose of 50 mg of phospholipids/kg improved lung pressure-volume characteristics of immature rabbit neonates to a level similar to that of mature neonates at term.

Amino Acid Sequence↗