Determinants of Slow Walking Speed in Ambulatory Patients Undergoing Maintenance Hemodialysis

Walking ability is significantly lower in hemodialysis patients compared to healthy people. Decreased walking ability characterized by slow walking speed is associated with adverse clinical events, but determinants of decreased walking speed in hemodialysis patients are unknown. The purpose of this study was to identify factors associated with slow walking speed in ambulatory hemodialysis patients. Subjects were 122 outpatients (64 men, 58 women; mean age, 68 years) undergoing hemodialysis. Clinical characteristics including comorbidities, motor function (strength, flexibility, and balance), and maximum walking speed (MWS) were measured and compared across sex-specific tertiles of MWS. Univariate and multivariate logistic regression analyses were performed to examine whether clinical characteristics and motor function could discriminate between the lowest, middle, and highest tertiles of MWS. Significant and common factors that discriminated the lowest and highest tertiles of MWS from other categories were presence of cardiac disease (lowest: odds ratio [OR] = 3.33, 95% confidence interval [CI] = 1.26–8.83, P<0.05; highest: OR = 2.84, 95% CI = 1.18–6.84, P<0.05), leg strength (OR = 0.62, 95% CI = 0.40–0.95, P<0.05; OR = 0.57, 95% CI = 0.39–0.82, P<0.01), and standing balance (OR = 0.76, 95% CI = 0.63–0.92, P<0.01; OR = 0.81, 95% CI = 0.68–0.97, P<0.05). History of fracture (OR = 3.35, 95% CI = 1.08–10.38; P<0.05) was a significant factor only in the lowest tertile. Cardiac disease, history of fracture, decreased leg strength, and poor standing balance were independently associated with slow walking speed in ambulatory hemodialysis patients. These findings provide useful data for planning effective therapeutic regimens to prevent decreases in walking ability in ambulatory hemodialysis patients.     

Reflections on the Conservation and Sustainable Use of Genetic Resources in the Deep Seabed Beyond the Limits of National Jurisdiction

Attention is increasingly being given to genetic resources in the deep seabed beyond the limits of national jurisdiction owing to their considerable potential scientific and economic value. At the same time, there are concerns that the increased demand for these genetic resources may result in their unsustainable collection or even in the extinction of species in the deep seabed. At present there is no specific legal framework governing these resources in international law. Thus, this article explores the relevant rules of international law applicable to the conservation and sustainable use of genetic resources in the deep seabed.     

Cloning of a Vero toxin (VT2) gene from a VT2-converting phage isolated from Escherichia coli 0157: H7

Abstract A Vero toxin (VT2 or Shiga-like toxin II)-converting phage was isolated from Escherichia coli 0157: H7 strain J-2. Nontoxigenic E. coli C600 produced VT2 when lysogenized with the toxin-converting phage. Eco RI fragments of the phage DNA were ligated with Eco RI-digested pBR322 or pUC118 and were transformed into E. coli MC1061 or MV1184. Transformants exhibiting VT2 production commonly contained a 4.6 kb Eco RI fragment. It was found that a 2.3 kb Kpn I- Sph I fragment coded VT2 production and that this fragment hybridized weakly with the 2.1 kb fragment encoding VT1.     

The nuclear matrix from rat liver is capable of phosphorylating exogenous tyrosine-containing substrates

The nuclear matrix isolated from rat liver phosphorylated exogenous tyrosine-containing substrates angiotensin II and synthetic polymer (Glu, Tyr; 4:1). The phosphorylation reaction was dependent on Mn2+ or Mg2+, but the former was the preferred ion. Km values for poly(Glu,Tyr; 4:1) and ATP were 0.2 mM and 4 microM, respectively. Angiotensin II showed a lower affinity for the kinase than poly(Glu,Tyr; 4:1). The isoflavone genistein, a specific inhibitor for tyrosine phosphorylation, inhibited the tyrosine kinase activity in the nuclear matrix.     

Determination of free sulphite in wine using a microbial sensor

Summary A microbial sensor of immobilized Thiobacillus thiooxidans S3 cells was assembled to determine free sulphite in wine. Sulphite oxidation activity of the immobilized cells was sufficiently high for use even after 3 months storage at 4° C. The sensitivity of this sensor was 116 nA·1·mg^-1 for sulphur dioxide. The relationship between the current decrease and the sulphur dioxide concentration was linear up to 17 mg·1^-1. The sampling rate achieved was 10 min per sample including washing time. This sensor method needed no pretreatment of wine samples, and wines diluted with 5 mM sulphuric acid solution could be directly introduced in the computer-aided analysis system. The pigments in red wine did not disturbed the analysis.     

Complete purification and immunochemical analysis of S-adenosylmethionine synthetase from bovine brain

We have purified S-adenosylmethionine (AdoMet) synthetase about 3000-fold from bovine brain extract. The Km values of the enzyme for L-methionine and ATP were 10 and 50 microM, respectively. An apparent molecular mass of the enzyme was estimated to be 160 kDa by gel filtration on a Sephacryl S-200 column. Sucrose density gradient centrifugation gave a sedimentation coefficient of 8 S. Polyacrylamide gel electrophoresis of the purified enzyme in native system revealed a single protein band, whereas two polypeptide bands with molecular masses of 48 kDa (p48) and 38 kDa (p38) were observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme. Antibody against bovine brain AdoMet synthetase was prepared by injecting the purified enzyme into a rabbit. Immunoblot analysis revealed that the antibody recognized both p48 and p38 in the impure enzyme preparations from bovine brain as well as in the purified enzyme. Specific antibodies against p48 and p38 were separated from the immunoglobulin fraction by an affinity purification, both of which inhibited the enzyme activity. These results indicate that AdoMet synthetase from bovine brain consists of two different polypeptides, p48 and p38.     

Further studies on the relationship between tyrosine supply and catecholamine production in cultured adrenal chromaffin cells.

To elucidate a possible role of tyrosine supply as a factor modulating catecholamine biosynthesis in the adrenergic cell, the transport of [14C]tyrosine into cultured bovine adrenal chromaffin cells was first examined, and the relationship between [14C]tyrosine transport and [14C]catecholamine formation was then investigated. Under the conditions which were routinely employed to determine the rate of catecholamine biosynthesis, tyrosine was taken up into the cells in a manner independent of extracellular Na+ and Ca2+, and this uptake was also insensitive to ouabain and various metabolic inhibitors. The stimulation of these cells with high K+ and other secretagogues caused no significant alteration in the uptake. While, tyrosine transport was markedly inhibited by tyrosine analogues and other L-aromatic amino acids, and this inhibition was accompanied by the reduction of [14C]catecholamine formation. In contrast, tyrosine transport was markedly enhanced by flavone, and this enhancement was also accompanied by the augmentation of catecholamine production under the same experimental conditions. These results seem to indicate that the transport of tyrosine into the cells may be closely related to catecholamine formation within the cells, thus providing an evidence for a possible role of tyrosine supply as one of the factors affecting catecholamine production in the adrenal chromaffin cell.     

A protein-tyrosine kinase in the nuclear matrix from rat liver

Protein kinase activity in isolated nuclei from rat liver was detected in situ after electrophoresis on SDS-polyacrylamide gel containing no exogenous protein substrate. After renaturation of polypeptides, the gel was incubated with [gamma-32P]ATP and divalent cations. Among five major protein kinase activities observed as radioactive bands by autoradiography, a protein kinase autophosphorylating on tyrosine (Mr 30,000) was identified and found to be localized in the nucleus, particularly in the nuclear matrix. The intensity of the activity band representing the level of the protein-tyrosine kinase in rat liver nuclei did not appreciably change during 3-24 h after partial hepatectomy.