The cytoplasmic malic enzyme (Mod-1) catalyzes the oxidative decarboxylation of malate: malate + NADP+---pyruvate + CO2 + NADPH + H+. Using a cDNA clone of Mod-1 as a probe, two new DNA markers not ...at the Mod-1 locus (restriction fragment length polymorphisms, RFLP) were detected by Southern blot analysis that showed extensive homology to Mod-1 sequences. Linkage of each restriction fragment length polymorphism to loci other than Mod-1 was assessed using the BXD (C57BL/6J x DBA/2J) recombinant inbred strains and confirmed by backcrosses. One polymorphic site, designated D9Rti1, was found to be closely linked to the phosphoglucomutase (Pgm-3) locus on Chromosome 9. The other hybridization site, designated D1Rti2, was closely linked to the isocitrate dehydrogenase (Idh-1) locus on Chromosome 1. The data presented imply that Mod-1 homologous sequences are tightly linked to three different metabolic enzymes.
Patients who have a decreased left ventricular (LV) ejection fraction (EF) may be denied coronary by-pass grafting (CABG) because it is assumed that improvement in function is unlikely. If the low ...LVEF were due to myocardial necrosis, this assumption would be valid. If the dysfunction were due to both necrosis and ischemia, however, then improvement may be possible with CABG. A method capable of identifying such patients would be useful. In this study, an "ischemic index" was determined for 37 patients based on the difference between the presurgical LVEF estimated from the standard 12-lead electrocardiogram by the Selvester QRS score (indicating the extent of dysfunction due to necrosis) and the presurgical LVEF measured from resting multigated radionuclide angiography (indicating dysfunction due to both necrosis and ischemia). It was hypothesized that a high ischemia index, that is, a large discrepancy between estimated and measured LVEF, would be associated with an improved post-surgical measured LVEF. The results showed that patients with an ischemic index of less than or equal to 0 had a mean decrease in LVEF of 8% (p = 0.02) and those with an index between 0 and 10 had no mean change. Patients with an index greater than or equal to 11, however, had a mean increase of 5% (p = 0.02), suggesting that depressed LVEF may improve following CABG among patients whose low function is due primarily to reversible ischemia as indicated by a high ischemic index.
We have synthesized and characterized bis(sulfo-N-succinimidyl) doxyl-2-spiro-5'-azelate (BSSDA), a membrane-impermeant bifunctional spin-labeling reagent. BSSDA is a nine carbon backbone homologue ...of bis(sulfo-N-succinimidyl) doxyl-2-spiro-4'-pimelate BSSDP; Beth et al. (1986) Biochemistry 25, 3824-3832. Due to its longer backbone, BSSDA can span longer distances between reactive groups on a protein than can BSSDP. However, the purpose of the bifunctional design of these reagents is to provide a tight motional coupling of the spin labels to the surface of a target protein. To test whether the longer backbone of BSSDA results in a greater local flexibility and thereby undermines the effects of bidentate attachment, we have labeled with BSSDA anion-exchange channels of intact human erythrocytes at the same site as we have previously labeled them with BSSDP. Linear and saturation-transfer EPR spectra of BSSDA-labeled anion-exchange channels in intact cells closely approximate the corresponding spectra from BSSDP-labeled channels. Thus, the longer backbone of BSSDA relative to BSSDP does not give rise to significant local flexibility, even when BSSDA is bound to a site that can be spanned by the shorter reagent.
We conducted a field experiment to assess interrelationships between leaf-tissue secondary chemistry, avian predation, and the abundance and diversity of arthropods occurring on sagebrush (Artemisia ...tridentata) in central Oregon. Arthropods were removed from individual shrubs, some of which were then caged to exclude birds. Secondary chemistry and arthropods were sampled at intervals up to 56 wk following the defaunation/caging treatment. Recovery rates differed among arthropod taxa and functional groups. Several sap-sucking homopterans and hemipterans reached control levels within 2-4 wk of the treatment, whereas abundances of parasitoids and predators recovered to match control numbers only 6 wk after defaunation. Abundances of several herbivorous leaf-chewing taxa (primarily lepidopteran larvae) remained significantly depressed even 56 wk after the treatment. Fungivores (oribatid mites) reached greater abundances on defaunated than on control shrubs by the end of the experiment. There were also significant changes in the concentrations or frequency of occurrence of several chemical compounds following the defaunation treatment. Several hydrocarbons, sesquiterpenes, and monoterpenes that were present in most shrubs exhibited sharply reduced concentrations in leaf tissues within 4 wk of the treatment, whereas some alcohols and ketones (linalool, borneol, thujone), which occurred at relatively low frequencies among control plants, increased dramatically in their frequencies of occurrence following arthropod removal. Both changes persisted for the duration of the experiment. We found several significant associations between the abundance or occurrence of arthropod taxa or groups and concentrations or frequencies of secondary compounds, but these were most prevalent among the leaf-chewing lepidopterans. We suggest that the shrubs responded to the removal of herbivorous, leaf-chewing arthropods by altering chemical allocation patterns; the changes in chemistry persisted for over a year because recolonization of the defaunated plants by these herbivores was slow. Effects of the caging treatment were much less obvious. The recovery of the diversity of arthropods known to constitute prey for birds in this system was slower on shrubs protected from avian predation than on exposed shrubs, but a year after defaunation diversity had increased to higher levels on the protected shrubs. Few arthropod taxa or functional groups differed in abundance or frequency of occurrence between caged and uncaged shrubs, although fungivores (which are not eaten by birds) increased to levels on protected shrubs that were nearly twice those on the uncaged controls by the end of the experiment. Between-shrub variance in the abundance and diversity of bird-prey taxa was greater among exposed than protected shrubs, possibly reflecting the effects of area-restricted searching by the birds. There were no differences in leaf-tissue secondary chemistry between caged and uncaged shrubs.
Previous studies have raised the concern that the reduction of diastolic blood pressure below 85 mm Hg among treated hypertensive patients may have cardiac hazards. However, these reports have not ...fully assessed potential confounding from coexisting cardiovascular disease.
We conducted a population-based case-control study to examine the relation between treated diastolic blood pressure and the risk of primary cardiac arrest among hypertensive patients free of clinically diagnosed cardiovascular disease. Cases were hypertensive enrollees of the Group Health Cooperative of Puget Sound, an HMO, who had primary cardiac arrest between 1977 and 1990 (n = 80). Control patients were a stratified random sample of hypertensive enrollees (n = 426). Ambulatory-care records were reviewed to assess blood pressures and other clinical characteristics. Medication use was assessed through the HMO computerised pharmacy database.
Logistic regression models suggested a curvilinear relation between the level of treated diastolic blood pressure and the risk of primary cardiac arrest, after adjustment for pretreatment diastolic blood pressure, antihypertensive therapy, and other potential confounders. Compared with a treated diastolic blood pressure of 85 mm Hg, a treated diastolic blood pressure of 80 mm Hg was associated with a small increase in risk (relative risk RR 1.2; 95% confidence interval CI 1.0, 1.6), 75 mm Hg was associated with a modest increase in risk RR 1.6; 95% CI 1.2, 2.1, and 70 mm Hg was associated with more than a twofold increase in the risk of primary cardiac arrest RR 2.3; 95% CI 1.4; 3.8). There was little evidence of effect modification by pretreatment diastolic blood pressure.
Our findings support available evidence that among hypertensive patients a treated diastolic blood pressure level below 85 mm Hg is associated with cardiac hazards.
The axillary vein is a suitable alternative to the jugular venous system for tunnelled silastic catheterization in neonates, and should be included in the armamentarium of the surgeon who treats ...neonates. It is technically easy and is comparable to the internal jugular vein in terms of complications. Proper positioning of the catheter tip can sometimes be problematic, but without a resultant increase in morbidity or mortality.
This study examined the relation between left ventricular (LV) function and the severity of acute myocardial ischemia in a conscious dog model. The LV ejection fraction (EF) was measured by ...multigated equilibrium radionuclide angiography, and regional myocardial blood flow was measured with radioactive microspheres before and 10 minutes after distal and then proximal occlusion of the left anterior descending (LAD, 13 dogs) or left circumflex (LC, 13 dogs) coronary artery. Two methods were used to evaluate the extent of ischemia. The first method determined the mass of myocardium that was ischemic based on different degrees of reduced blood flow. The second method estimated the severity of ischemia expressed as blood flow deficit resulting from each coronary occlusion. Global LV function was very sensitive to ischemia, and the relation between change in function and the degree of ischemia were described best by linear functions. The best linear correlation between mass of ischemic myocardium and percent reduction in EF resulted from the ischemic region defined as all tissue with 25% or greater reduction in blood flow, r=0.84 for LAD (Y = 0.96X + 1.8) and r = 0.75 for LC (Y = 0.53X + 2.0) occlusions. Defining ischemic mass by more severe reduction in blood flow resulted in exclusion of ischemic myocardium that affected function. The myocardial blood flow deficit also correlated linearly with percent reduction in EF, r = 0.89 for LAD (Y = 1.3LY + 2.7) and r = 0.81 for LC (Y = 0.83X - 0.1) occlusions. The slope of the regression lines using both analyses of ischemia were significantly greater (p< 0.01) for LAD than LC occlusions, indicating that for comparable degrees of ischemia LAD as compared to LC occlusion decreased EF to a greater extent. Calculation of EF from attenuated corrected volumes resulted in small changes in LAD, but not LC, EF and did not account for the disproportionate effects of LAD and LC ischemia. In a separate group of studies (n = 18) EF measured by radionuclide angiography after LAD or LC occlusions correlated well with biplane contrast angiography r= 0.93, SEE 5.1. These data suggest that disportionately greater effects of LAD compared to LC ischemia on global EF in the dog are due primarily to different pathophysiologic responses to ischemia.
Findings suggest the need for research to examine the efficacy of interventions building on adolescent females' desire to avoid pregnancy. Study findings also suggest that interventions promoting ...improved parent-adolescent communication and improved parental supervision may contribute to adolescents' use of dual methods for STD and pregnancy prevention. (Original abstract - amended)
Reports of Special Committees (Technical) Cobb, Rodney D.; Day, M. H.; Hanson, C. M. ...
Proceedings of the Association of Official Seed Analysts,
01/1962, Letnik:
52
Journal Article
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