Structural polymorphism of glycophorins demonstrated by immunoblotting techniques

We have explored the polymorphism of the glycophorin system in the human erythrocyte membrane using the immunoblotting techniques and examining 52 individuals selected without prior bias as to their serologic state and ten documented serologic variants of M, N, S, s blood group system. Polyclonal antisera to alpha glycophorin and to alpha glycophorin CNBr carboxyl terminal fragment C (residues 82-131) and M and N specific monoclonal antibodies (MoAbs) were used. The first two reagents detect specific regions of the alpha glycophorin molecule and all electrophoretically resolved species of glycophorins immunologically related to alpha and delta glycophorins (delta glycophorin, [alpha-delta] hybrids and other glycophorins with an alteration in the carboxyl terminal segment); the M and N MoAbs identified the glycophorin species containing or lacking the M or N determinant in the amino terminal octapeptide structures. We find that immunoblotting confirmed in all cases the serologically determined phenotype; we also find that polymorphic forms of the glycophorin system are relatively infrequent; immunoblotting, independent from serologic testing, was capable of detecting five mutants, two most likely S-s-U-phenotypes; a new glycophorin species was detected in normal red cells with both antiglycophorin and antipeptide C sera, which is not evident with MoAbs; immunoblots of known glycophorin variants (En(a-), U-, Mg, Mi I, II, III, V, and Sta) confirmed but also extended our knowledge of the abnormal glycophorins involved; and the He+ and Wrb(-) cells showed normal patterns.     

Recent Developments in the Role of Coenzyme Q10 for Coronary Heart Disease: a Systematic Review

Purpose of Review

This review examines recent randomized clinical trials evaluating the role of coenzyme Q10 (CoQ10) in the management of coronary heart disease.

Recent Findings

CoQ10 is one of the most commonly used dietary supplements in the USA. Due to its antioxidant and anti-inflammatory effects, CoQ10 has been studied extensively for possible use in managing coronary heart disease. One of the most common applications of CoQ10 is to mitigate statin-associated muscle symptoms (SAMS) based on the theory that SAMS are caused by statin depletion of CoQ10 in the muscle. Although previous studies of CoQ10 for SAMS have produced mixed results, CoQ10 appears to be safe. Because CoQ10 is a cofactor in the generation of adenosine triphosphate, supplementation has also recently been studied in patients with heart failure, which is inherently an energy deprived state. The Q-SYMBIO trial found that CoQ10 supplementation in patients with heart failure not only improved functional capacity, but also significantly reduced cardiovascular events and mortality. Despite these positive findings, a larger prospective trial is warranted to support routine use of CoQ10. Less impressive are the effects of CoQ10 on specific cardiovascular risk factors such as blood pressure, dyslipidemia, and glycemic control.

Summary

Current evidence does not support routine use of CoQ10 in patients with coronary heart disease. Additional studies are warranted to fully determine the benefit of CoQ10 in patients with heart failure before including it in guideline-directed medical therapy.

     

Symposium on obesity and asthma �CNovember 2, 2006

Asthma and obesity are frequently associated, and obesity has been considered a factor contributing to both an increase in severity of asthma and to its development. The present document summarizes the proceedings of a symposium held in Montreal, Quebec, on November 2, 2006, under the auspices of the Réseau en santé respiratoire du Fonds de la recherche en santé du Québec in collaboration with the McGill University – Strauss Severe Asthma Program, Université Laval (Quebec City) and Université de Montréal. It includes an overview of the various aspects of the relationships between asthma and obesity with regard to animal models; genetic, hormonal and physiological determinants; influence of comorbidities (eg, sleep apnea syndrome); epidemiology; clinical and psychological features; and management of asthma in the obese population.     

Cytogenetic and histologic correlations in malignant lymphoma

Although a number of studies have indicated correlations between histologic subtypes of tumors and certain nonrandom chromosome changes, cytogenetic studies of lymphoma are in an early stage compared to those of leukemia. No comprehensive analysis of available data has so far been attempted in the literature either. Here we present an analysis of chromosome changes and their correlation with subtypes of lymphoma studied by conventional histology and cell surface markers, as observed in two sets of data: a group of 65 karyotypically abnormal tumors sequentially ascertained and studied by us during the period January 1, 1984 to April 30, 1985, and a larger data set derived by combining our data with those from two published series from the University of Minnesota that are comparable to our data. These combined data, which comprise the largest data set on the cytogenetics of lymphomas assembled so far, enabled a comprehensive analysis of correlation between chromosome change and tumor histology and the patterns of chromosome instability in these tumors. We found several significant associations, some previously described and others now recognized, between nonrandom chromosome gains, breaks, translocations, and deletions and histologic subtypes of tumors that characterize lymphomas. The data indicate that finding of chromosome breaks at certain sites (eg, 8q24, 14q32, 18q21) is of diagnostic value in dealing with cases of unusual lymphoma. Furthermore, nonrandom chromosome breakage exhibited three distinct patterns that reflected three levels of etiologically relevant genetic change.     

Hemorrhagic tumor necrosis during a pilot trial of tumor necrosis factor-alpha and anti-GD3 ganglioside monoclonal antibody in patients with metastatic melanoma

Hemorrhagic tumor necrosis is an inflammatory event that leads to selective destruction of malignant tissues, with both potentially toxic and beneficial consequences. A pilot clinical trial was undertaken combining tumor necrosis factor-alpha (TNF-alpha) with the monoclonal antibody R24 (MoAb R24) against GD3 ganglioside in patients with metastatic melanoma. Patients received MoAb R24 to recruit leukocytes to the tumor followed by low doses of recombinant TNF-alpha to activate leukocytes. Eight patients were treated and seven patients had mild toxicity. One patient with extensive metastatic melanoma developed tumor lysis syndrome within hours after treatment with almost complete necrosis of bulky tumors in multiple visceral sites. To our knowledge, this is the first documented case of hemorrhagic tumor necrosis in a patient with metastatic cancer in multiple visceral sites.     

Evidence for increased in vivo sodium-potassium pump activity and potassium efflux in skeletal muscle of spontaneously hypertensive rats

We have used 87Rb nuclear magnetic resonance spectroscopy (NMR) to study in vivo rubidium kinetics in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) controls, using rubidium as a marker for potassium. We gave 15 male, 13-week-old SHR, mean +/- s.d. blood pressure 180 +/- 10 mmHg, and 15 age-matched normotensive controls, mean blood pressure 120 +/- 9 mmHg, a daily dose of RbCl (2 mmol/kg intraperitoneally). We made repeated NMR measurements of skeletal muscle rubidium concentrations until steady state was reached. We then withdrew rubidium and made further measurements of rubidium concentrations, at intervals, for up to 1 week after the last injection. We also measured plasma and erythrocyte rubidium concentrations by flame atomic absorption spectroscopy at similar intervals after the withdrawal of rubidium. Rubidium concentrations rose at a faster rate in SHR skeletal muscle, but the steady-state muscle rubidium concentration was the same (45 mmol/l) in both SHR and WKY rats. There was also a threefold increase in the rate of rubidium efflux from both muscle and erythrocytes in SHR. These results are consistent with a marked increase in Na+,K(+)-ATPase activity and an increase in the rate of rubidium efflux in vivo in SHR. The increased rate of rubidium efflux in SHR could represent increased K+ efflux via calcium-activated K+ channels and/or result as part of cell volume regulation secondary to increased Na(+)-H+ antiporter activity.     

Influence of isoprostane F2alpha-III on reflow after myocardial infarction.

AIMS: To investigate whether the vasoconstrictor isoprostane F2alpha-III (iPF2alpha-III), released during myocardial reperfusion, contributes to the low/no reflow phenomenon observed following acute myocardial infarction (AMI). METHODS AND RESULTS: Thirteen patients undergoing primary percutaneous coronary intervention (PCI) for AMI had iPF2alpha-III measured by high-performance liquid and gas chromatography-mass spectrometry. Isoprostane F2alpha-III concentrations were significantly higher following PCI than in controls (1.5+/-1.3 vs.16+/-0.06 nM, p < 0.001). Mean iPF2alpha-III concentration correlated positively with ST-segment resolution at 90 min (R = 0.62, p < 0.05). In the isolated murine heart: (a) coronary vasoconstriction occurred at, or above, iPF2alpha-III concentrations of 1 microM. From 1 to 10 microM, iPF2alpha-III induced dose-dependent vasoconstriction (p = 0.005) with reduction in coronary flows (f) of 57+/-5% and 31+/-4% (percentage baseline), respectively; (b) SQ29548 1 microM completely reversed the vasoconstrictive effects of iPF2alpha-III 10 microM; (c) SQ29548 1 microM infused during reperfusion following 30 min ischaemia had no effect on CF or infarct volume. CONCLUSION: Concentrations of iPF2alpha-III released into the venous circulation during reperfusion following AMI in humans are significantly lower than those required to diminish coronary flow in the murine heart; increased levels indicate successful reperfusion. Inhibition of iPF2alpha-III has no effect on coronary flow or infarct size in the murine heart, suggesting that iPF2alpha-III alone does not account for the low/no reflow phenomenon observed following AMI.     

GNAS1 mutational analysis in pseudohypoparathyroidism

OBJECTIVE

Mutations of the GNAS1 gene, which is located on chromosome 20q13.11 and encodes the α-subunit of the stimulatory GTP-binding protein, have been identified in patients with pseudohypoparathyroidism type Ia (PHPIa) and pseudopseudohypoparathyroidism (PPHP). We have undertaken studies to determine the prevalence of GNAS1 mutations and to explore methods for their more rapid detection.

METHODS

Thirteen unrelated families (8 with PHPIa and PPHP patients, and 5 with PPHP patients only) were investigated for GNAS1 mutations in the 1050 base-pair (bp) region spanning exons 2–13 by single-stranded conformational polymorphism (SSCP) and DNA sequence analysis.

RESULTS

GNAS1 mutations were detected in 4 of the 8 families with PHPIa patients. These consisted of: two novel de novo missense mutations (Pro115Ser and Glu259Val) in two families and an identical 4 bp deletion of codons 189 and 190 resulting in a frameshift in two unrelated families. These results expand the spectrum of GNAS1 mutations associated with this disorder and confirm the presence of a mutational hot-spot involving codons 189 and 190. SSCP analysis was found to be a specific and sensitive method that detected all 4 mutations. GNAS1 mutations were not detected in any of the PPHP only families.

CONCLUSIONS

The pseudohypoparathyroid disorders appear to represent a heterogeneous group with GNAS1 mutations forming the molecular aetiology in approximately 50% of pseudohypoparathyroidism type Ia families. Such mutations can be reliably identified by single-stranded conformational polymorphism and this will help to supplement the clinical evaluation of some patients and their families, particularly as the disease may not be fully penetrant.

     

A protein phosphatase related to the vaccinia virus VH1 is encoded in the genomes of several orthopoxviruses and a baculovirus.

The vaccinia virus VH1 gene product is a dual specificity protein phosphatase with activity against both phosphoserine- and phosphotyrosine-containing substrates. We investigated the potential presence of VH1 analogs in other viruses. Hybridization and sequence data indicated that a phosphatase related to the VH1 phosphatase is highly conserved in the genomes of smallpox variola virus and other orthopoxviruses. The open reading frames from the raccoonpox virus and the smallpox variola virus Bangladesh major strain genomes encoding the VH1 analogs were sequenced and found to be highly conserved with the vaccinia virus VH1. An open reading frame from the baculovirus Autographa californica has sequence similarity to the VH1 phosphatase. The viral proteins appear to be structurally related to the cell cycle control protein p80cdc25. A recombinant phosphatase expressed from the baculovirus gene was found to share with the VH1 phosphatase the ability to hydrolyze substrates that contained both phosphoserine and phosphotyrosine.