Regression of left ventricular hypertrophy results in improvement of QT dispersion in patients with hypertension

OBJECTIVES: Increased QT dispersion has been considered as predisposing to ventricular arrhythmias in hypertrophic cardiomyopathy, congestive heart failure, and coronary artery disease. An increased QT dispersion has also been found in hypertensive patients with left ventricular hypertrophy (LVH). The data on the effect of LVH regression on QT dispersion are limited. METHODS AND RESULTS: To assess the relation of LVH regression and QT dispersion decrease, 68 patients (42 men and 26 women, mean age 56.3+/-9.5 years) with uncomplicated essential hypertension were studied. All underwent full electrocardiographic and echocardiographic studies at baseline and after 6 months of monotherapy, 29 with angiotensin-converting enzyme inhibitors and 39 with calcium antagonists. QT dispersion was calculated by subtracting the shortest QT from the longest QT, in absolute value (QTmax - QTmin). It was also corrected with Bazett's formula (QTc dispersion). Left ventricular mass index was assessed according to the Devereux formula. After treatment, LVH decreased with both angiotensin-converting enzyme inhibitors (from 155 to 130 g/m2, P < .001) and calcium antagonists (156 to 133/92/m2, P < .001). QT dispersion decreased both after angiotensin-converting enzyme inhibitor treatment (from 82 to 63 ms) and calcium antagonist treatment (from 77 to 63 ms, both P < .001 ). There was a significant correlation of QT dispersion and left ventricular mass after therapy (r = 0.36, P < .005). There was a correlation of the degree of LVH and QT dispersion decrease (r = 0.27, P < .05). CONCLUSIONS: It is concluded that LVH regression influences AQT favorably. Its prognostic value has yet to be determined.     

Infrapopliteal bypasses to severely calcified, unclampable outflow arteries: two-year results

PURPOSE: Although severe, circumferential calcification of distal outflow vessels is frequently encountered, its effect on bypass graft patency rates has not been well established. METHODS: Using a computerized vascular registry database, we conducted a retrospective review of 1957 bypass grafts with distal anastomoses to infrapopliteal vessels performed at a single institution between 1990 and 1995. Of these cases, 101 procedures involved outflow arteries classified by the operating surgeon as severely calcified and unclampable (requiring intraluminal occluders for vascular control), whereas in 105 cases the outflow arteries had no calcification present at the distal anastomotic site. The remaining cases had varying intermediate degrees of calcification and were not analyzed. Indication for bypass procedure was limb-threatening ischemia in 90% of severe calcification cases and in 84% of cases without calcification. Atherosclerotic risk factors were similar except for the presence of diabetes (92% vs 74%, p < 0.001), creatinine level > 2.0 mg/dl (21% vs 8%, p < 0.01), and dialysis dependency (17% vs 3%, p < 0.001), all of which were more prevalent in the severe calcification group. Infrapopliteal distal anastomotic location and type of conduit ( > 90% autogenous vein) were comparable between groups. RESULTS: Primary patency, secondary patency, and foot salvage rates at 24 months were 60%, 65%, and 77% for the severe calcification group and 74%, 82%, and 93% for the no calcification group, respectively. With secondary procedures comprising 26% of cases in each group, data from the 150 primary procedures were reanalyzed separately. In this primary procedure group, 24-month primary patency, secondary patency, and foot salvage rates were 66%, 69%, and 77% for the severe calcification group and 84%, 90%, and 96% for the no calcification group, respectively. Although patency and salvage rates were consistently lower for the severe calcification group in all analyses, these differences did not achieve significance by log-rank life-table analysis at 2-year follow-up. Perioperative 30-day mortality (0.99% severe calcification vs 0.95% no calcification) and 24-month survival rates (84% severe calcification vs 83% no calcification) were also similar between groups. CONCLUSION: These data suggest that effective techniques exist to perform infrapopliteal bypasses to severely calcified, unclampable outflow arteries with results comparable with those obtained with clampable, uncalcified vessels. The finding of severe, circumferential calcification of outflow target arteries should not dissuade vascular surgeons from distal bypass for limb salvage indications.     

Interaction of short nucleotide derivatives with nucleic acids. IV. Modification of DNA by an alkylating tetranucleotide reagents in the presence of effectors in perfect and imperfect complexes

It was demonstrated that any mismatches in a complex formed by an ssDNA target and a tetranucleotide at 25 or 37 degrees C can be discriminated by alkylating the DNA with a tetranucleotide carrying a 4-[N-methyl-N-(2-chloroethyl)]aminobenzylethylamine residue at the 5'-terminal phosphate in the presence of a pair of flanking effectors, octanucleotide di-N-(2-hydroxyethyl)-phenazinium derivatives. The discrimination factor (ratio of the extent of the target modification in the perfect and mismatch-containing complexes) for a single mismatch in the tetranucleotide binding site at 25 degrees C varied between 4 and 500 depending on the type of mismatch and its location in the complex and exceeded 400 at 37 degrees C for all the investigated mismatches. The DNA target modification by the alkylating derivative of the 3'-estrone ester of tetranucleotide pCAGX (mean = C, T, A or G) was selective in the presence of a pair of hydrophobic effectors, octanucleotide 5'-cholesteryl-3'-phenazinium derivatives. The discrimination factors for 3'-terminal mismatches T.G, A.G, and G.G were 1,8,400, and 400, respectively.     

Fabrication of sulfonic acid chemisorption fibre by graft polymerization

A sulfonic acid fibre was fabricated by graft copolymerization of p-styrenesulfonate to Vion KN-1 fibre using redox and peroxide initiating systems with a static exchange capacity of 2 meq/g. Use of a redox initiating system in graft copolymerization causes the formation of up to 20–50 wt. % homopolymer, while the mass of homopolymer deceases to 10–25% in peroxide initiation. Repeated graft copolymerization of the monomer remaining in the solution virtually does not increase the effective degree of conversion.All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 1, pp. 28–31, January–February, 1994.     

Amebic keratitis in a wearer of disposable contact lenses due to a mixed Vahlkampfia and Hartmannella infection

PURPOSE: To support the hypothesis that Acanthamoeba is not a unique cause of amebic keratitis, we report a case of amebic keratitis in which viable Acanthamoeba could not be isolated from corneal tissue. Vahlkampfia and Hartmannella, two other genera of free-living ameba, were isolated, however, using prolonged culture. METHODS: A 24-year-old wearer of soft contact lenses had keratitis. Extensive histologic and microbiologic investigations were performed on corneal scrape, biopsy, and keratoplasty tissue. Contact lenses, storage case, and the home water supply, where contact lens hygiene was practiced, were examined for the presence of micro-organisms. RESULTS: No viruses, pathogenic bacteria, or fungi were detected from corneal tissue samples. Amebae were observed using light and electron microscopy, but these could not be unequivocally classified using immunocytochemical staining. Viable Vahlkampfia and Hartmannella, but no Acanthamoeba, were isolated from the corneal biopsy sample. Indirect immunofluorescence with a range of polyclonal rabbit antisera raised against axenically cultivated stains of the three amebal genera was unhelpful because of cross-reactivity. A diverse range of micro-organisms was present within the storage case, including the three amebal species. Amebic cysts also were associated with the contact lens. CONCLUSION: A mixed non-Acanthamoeba amebic keratitis has been identified in a wearer of soft contact lenses where lack of storage case hygiene provided the opportunity for the free-living protozoa Vahlkampfia and Hartmannella to be introduced to the ocular surface. When Acanthamoeba-like keratitis occurs, but where Acanthamoeba cannot be isolated using conventional laboratory culture methods, alternate means should be used to identify other amebae that may be present. Polyclonal immunofluorescent antibody staining was unreliable for generic identification of pathogenic free-living amebae in corneal tissue.     

Chemiluminescent detection of mRNAs on northern blots with digoxigenin end-labeled oligonucleotides

To establish a simplified, nonradioactive approach for identifying mRNAs on Northern blots, antisense oligonucleotides have been used as probes in combination with chemiluminescence-based detection. Oligonucleotides (approximately 32-mer) were end-labeled with digoxigenin (DIG) and used in conjunction with adamantyl 1,2-dioxetane aryl phosphate substrates (Lumigen PPD and CSPD). Oligonucleotides were designed as probes for several mRNAs in tissues of rats and mice, including the mitochondrial uncoupling protein, lipoprotein lipase, GLUT1, GLUT4, and beta-actin. Uncoupling protein mRNA was detected in total RNA from brown adipose tissue with a 32-mer DIG-labeled oligonucleotide, within 2 min of exposure to film. This mRNA could also be detected when as little as 250 ng of total RNA was applied to the gel, following 4 h exposure to film, and was present only in brown fat. The mRNA for lipoprotein lipase was detectable with a 30-mer DIG-labeled oligonucleotide in 1 micrograms of total RNA from mouse heart, within 2 h of exposure. The mRNA for the GLUT1 glucose transporter was detected in total RNA from rat midbrain using a 32-mer DIG-labeled oligonucleotide, while beta-actin mRNA was detected with a 30-mer oligonucleotide. The mRNA for the insulin-sensitive glucose transporter GLUT4 was detected with a 32-mer DIG-labeled oligonucleotide and found only in those tissues in which glucose uptake is stimulated by insulin. The speed of detection was greater with CSPD and was augmented by exposure of membranes to film at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)