The role of polypyrrole as charge transfer mediator and immobilization matrix for d-fructose dehydrogenase in a fructose sensor

A fructose dehydrogenase (FDH) modified electrode is produced by the electroadsorption of a layer of FDH on a platinum electrode followed by the electropolymerization of a polypyrrole (PPy) film around and over the enzyme. This immobilizes and stabilizes the enzyme as well as providing an electron transfer pathway to the electrode. The amperometric response to fructose and the enzymatic activity are measured as a function of PPy film thickness. The electrode is shown to have a maximum response at a PPy thickness of approximately the thickness of the enzyme layer. A measure of the electrode efficiency is also obtained, this is the amperometric response to fructose as a percentage of that expected on the basis of the enzyme activity. The functioning of the electrode is also dependent on the counter-ion used for PPy polymerization. This is shown to be mainly related to the nucleation and growth of the PPy film in the interfacial region.     

Prostaglandin F2 alpha increases responsiveness of pulmonary airways in dogs

We studied the effect of prostaglandin F2 alpha (PGF2 alpha) on the responsiveness of pulmonary airways in dogs. Airway responsiveness was assessed by determining the bronchoconstrictor response to increasing concentrations of acetylcholine aerosol delivered to the airways. In each of five dogs, we determined responsiveness during treatment with physiologic saline, histamine, or PGF2 alpha aerosols. The doses of histamine and PGF2 alpha were determined by establishing the largest dose of each which could be given to the dog without causing bronchoconstriction (subthreshold doses). We found that airway responsiveness was not significantly different during histamine treatment than after saline, however, responsiveness increased during treatment with PGF2 alpha. In addition, the hyperresponsiveness induced by PGF2 alpha was prevented by pretreatment with the ganglion blocking drug hexamethonium (5 mg/kg given intravenously). The results show that PGF2 alpha specifically increases the responsiveness of pulmonary airways in doses that do not cause bronchoconstriction, and suggest that the hyperresponsiveness involves a neural mechanism such as increased responsiveness of airway sensory nerves.     

A case of hypokalemic myopathy associated with transient hypothyroidism

A case of transient hypothyroidism in the course of hypokalemic myopathy is reported. A 69-year-old woman had severe muscle weakness and marked potassium deficiency associated with alkalosis during treatment with thiazide diuretics. The cause of muscle weakness proved to be hypokalemic myopathy confirmed by clinical findings and muscle biopsy. After the episode of hypokalemic myopathy, serum levels of thyroid hormone were lowered (T4; 3.8 micrograms/dl, T3; 54 ng/dl) and that of TSH was elevated (25.1 microU/ml). Antithyroid microsomal antibody was positive (1:25600) and anti-thyroglobulin antibody was negative. About one month after potassium supplement, her thyroid functions returned to normal, along with normalization of serum potassium level. This is the first documented case report of hypokalemic myopathy accompanied by transient hypothyroidism in a patient with autoimmune thyroiditis. We suggest that this transient hypothyroidism might be induced by hypokalemia during the course of autoimmune thyroiditis.     

Transformations in isolated polyhooks.

Polyhooks from certain non-flagellated mutants of Salmonella and Escheriohia coli are known to be helix-shaped under physiological conditions. However, two non-helical forms were found to occur in isolated polyhooks under appropriate conditions. One form is straight, and appeared when the pH was decreased to 3.2 or lower. The helical-to-straight transformation was reversible. The other form is a doughnut with a fairly constant diameter of above 0.1 μm, which was produced when polyhooks were heated at 75 °C in the absence of salts.     

Establishment of a variety of human bone marrow stromal cell lines by the recombinant SV40-adenovirus vector.

Various human bone marrow stromal cell lines were established from the adherent cell populations by introduction of the recombinant SV40-adenovirus vector with an infection or electric poration procedure. As compared with DNA transfection, the vector introduction was able to immortalize the cells with more than 100 times higher efficiency. Morphological and cytochemical analyses indicated that various cloned cell lines with different properties were isolated by the vector introduction. All the established cell lines expressed SV40 large T antigen. These results provided the evidence indicating that the recombinant SV40-adenovirus vector was a useful tool to establish a variety of cell lines with different biological activities from human bone marrow stroma.     

cDNA cloning and expression of rat tissue factor pathway inhibitor (TFPI).

Tissue factor pathway inhibitor (TFPI) is a factor Xa-dependent inhibitor for the factor VIIa-tissue factor complex. We isolated cDNA for rat TFPI by screening a lambda gt10 rat liver cDNA library. We determined the 1,228 bp nucleotide sequence, comprising a 88 bp 5' non-coding region, a 906 bp open reading frame, and a 234 bp 3' non-coding region, which encodes a protein of 302 amino acid residues. On Northern blot analysis of rat TFPI mRNA, rat TFPI mRNA was detected as two forms with different molecular sizes, 4.0 and 1.4 kb, which were expressed abundantly in heart, lung, kidney, and aortic endothelial cells. The homology of the amino acid sequence of rat TFPI with those of human and rabbit TFPI was found to be 60.7 and 57.4%, respectively. The lengths of the three tandem Kunitz-type inhibitor domains were strictly conserved not only among TFPI from the three species, but also among other proteins containing Kunitz-type inhibitor domains. The homology of the Kunitz-type domains in TFPI among the three species was 57, 86, and 69% in the 1st, 2nd, and 3rd domains, respectively. There was no significant difference in hydropathy profiles of TFPI from man, rabbit, and rat.     

Differential effects of body weight, hyperinsulinemia and oral glucose load on serum C-peptide/insulin molar ratio.

Serum C-peptide immunoreactivity (CPR)/immunoreactive insulin (IRI) molar ratio was determined in 136 subjects without renal, hepatic and thyroid disorders, at fasting, and during the initial period of 75 g-oral glucose tolerance test. The subjects were divided into 4 groups based on their body weight and age; Group A, young (< 55 years) and normal body weight (body mass index [BMI, kg/m2] < or = 25) subjects; Group B, young and overweight (BMI > 25) subjects; Group C, aged (> or = 55 years) and normal body weight (BMI < or = 25) subjects; Group D, aged and overweight subjects. Fasting CPR/IRI ratio and absolute CPR level negatively correlated in Groups B and D but not in A and C. After oral glucose load with elevation of insulin, CPR/IRI ratio invariably declined in all groups and significant negative correlation between CPR/IRI and CPR was found in Groups A, B and D but not in C. Slope of the regression lines obtained for correlation between CPR/IRI ratio and CPR were significantly steeper at fasting compared to the post-stimulation phase. CPR/IRI ratio is affected by hyperinsulinemia and oral glucose load but not by obesity alone. Assuming that CPR/IRI ratio reflects hepatic extraction of insulin, the insulin clearance at fasting is progressively reduced with increasing insulin secretion in overweight subjects: failure to detect such phenomenon in normal body weight subjects may be due to a narrower CPR range in this population. Insulin metabolism at fasting and during glucose stimulation is likely to be regulated by distinct factors.     

Human endometrial stromal cells and decidual cells express cluster of differentiation (CD) 13 antigen/aminopeptidase N and CD10 antigen/neutral endopeptidase.

With specific monoclonal antibodies, we found that human endometrial stromal cells and decidual cells express two function-related surface antigens. Indirect immunofluorescence staining revealed that both endometrial stromal cells and decidual cells during the first trimester of pregnancy expressed cluster of differentiation (CD) 13 antigen and CD10 antigen, which are identical to aminopeptidase N and neutral endopeptidase, respectively. By flow cytometric analysis, CD13 antigen was detected on 82-93% of the examined cells, and CD10 antigen was detected on 75-93% of the examined cells in endometrial stromal cell-enriched preparations. Furthermore, peptidase activity was detected in these cell preparations by an assay based on the hydrolysis of alanine-p-nitroanilide into p-nitroaniline and alanine.     

M ring, S ring and proximal rod of the flagellar basal body of Salmonella typhimurium are composed of subunits of a single protein, FliF.

The flagellar basal body, a major part of the flagellar motor, consists of a rod and four rings. When the fliF gene of Salmonella typhimurium, which was previously shown to code for the component protein of the M ring, was cloned and overexpressed in Escherichia coli, the FliF subunits formed ring structures in the cytoplasmic membrane. Electron microscopic observation of the purified ring structures revealed that each was composed of two adjacent rings and a short appendage extending from the center of the rings. Antibodies raised against the purified FliF protein decorated both the M and S rings of the intact basal body. We conclude that the FliF protein is the subunit protein of the M ring, and of the S ring and of part of the proximal rod of the flagellar basal body.