Diabetes and employment productivity: does diabetes management matter?

OBJECTIVE: To determine whether labor market effects were the result of diabetes per se or rather depended on the degree to which diabetes was controlled through management of blood sugar levels. METHODS: This study utilized data from a recently completed survey of households in Brownsville, Texas, a largely Mexican American community with a high prevalence of diabetes that is located on the Texas-Mexico border. Diabetes management, or control, was measured by blood sugar levels, glycosylated hemoglobin (A1C) levels, and interaction terms. Methods used were probit and Heckman regression. RESULTS: Management of diabetes did not appear to have a discernible impact on labor market outcomes in the short run. However, diabetes was negatively associated with male productivity, particularly in males' propensity to work. The new American Diabetes Association (ADA) definition of diabetes is based on having an A1C level of <6.5%. Using the new ADA definition, diabetes was negatively associated with female productivity. Female productivity was also negatively associated with the new ADA definition of prediabetes (A1C levels between 5.7% and 6.4%). However, very few people with diabetes actually controlled their blood sugar or A1C levels. CONCLUSION: These results imply that in order to avoid productivity losses associated with diabetes, more scarce prevention resources should be spent on prevention of the onset of diabetes than on the management of A1C for those already diagnosed with diabetes. For women, the prevention of prediabetes is key.

Flagellum-independent surface migration of Vibrio cholerae and Escherichia coli.

Surface translocation has been described in a large variety of microorganisms, including some gram-negative enteric bacteria. Here, we describe the novel observation of the flagellum-independent migration of Vibrio cholerae and Escherichia coli on semisolid surfaces with remarkable speeds. Important aspects of this motility are the form of inoculation, the medium composition, and the use of agarose rather than agar. Mutations in several known regulatory or surface structure proteins, such as ToxR, ToxT, TCP, and PilA, did not affect migration, whereas a defect in lipopolysaccharide biosynthesis prevented translocation. We propose that the observed surface migration is an active process, since heat, protease, or chloramphenicol treatments of the cells have strong negative effects on this phenotype. Furthermore, several V. cholerae strains strongly expressing the hemagglutinin/protease but not their isogenic hap-negative mutants, lacked the ability of surface motility, and the treatment of migrating strains with culture supernatants from hap strains but not hap-null strains prevented surface translocation.

[The postradiation use of vitamin-containing complexes and a phycocyanin extract in a radiation lesion in rats]. / Postradiatsionnoe primenenie vitaminsoderzhashchikh kompleksov i ékstrakta fikotsianina pri luchevom porazhenii krys.

Wistar rats have been exposed to X-rays with a dose of 5 Gy. Significant decrease in dehydrogenase activity, energy-rich phosphate level and efficiency of antioxidant defence and significant increase in pyruvate amount were observed within 4 weeks. It was also found that the feeding of exposed rats with phycocyanin extract from blue-green algae Spirulina platensis lead to correcting effect. The same result was observed after injections of tocopherol or complex of six water-soluble vitamins. The combination of above mentioned compounds had more marked effect, especially at the presence unitiole and Na2Se.

The role of the sodium cycle of energy coupling in the emergence and persistence of natural foci of modern cholera.

A hypothesis on the appearance and persistence of natural foci of cholera based on ecological and bioenergetic features of the process has been developed. The main causes of persistence and propagation of modern cholera are: 1) inability of various bacteria, including the genus Vibrio and many cyanobacterial species, to perform energy coupling, depending on external conditions, by means of two cycles (the proton and sodium cycles); induction of the sodium cycle of energy coupling increases the resistance of bacteria to various environmental factors, such as high concentrations of sodium, alkaline pH, and a high proton conductance of coupling membranes [1], and probably the virulence of the vibrios; 2) development of cyanobacteria in an aquatic environment enriched with Na+ accelerates alkalization of the medium and stimulates the development of the community of cyanobacteria with Vibrio cholerae, an autochthonous inhabitant of saline water bodies and marine shallow waters; 3) salinization of water bodies accelerates their blooming and enriches them with soluble organic matter, a substrate for vibrios inhabiting the biotope; 4) further propagation of cholera infection is related to eating heat-untreated hydrobionts from blooming water bodies [2].

Light-dependent delta mu Na-generation and utilization in the marine cyanobacterium Oscillatoria brevis.

Light-dependent Na+ and H+ transports, membrane potential (delta psi) and motility have been studied in the cells of the marine cyanobacterium Oscillatoria brevis. In the presence of a protonophorous uncoupler, carbonyl cyanide-m-chlorophenylhydrazone, the intracellular Na+ level is shown to increase in the dark and decrease in the light. The Na+/H+ antiporter, monensin, stimulates the dark CCCP-dependent [Na+]in increase and abolishes the light-dependent [Na+]in decrease. Na+ ions are necessary for the fast light-induced delta psi generation and H+ uptake by the cells. This uptake is inhibited by monensin being resistant to CCCP. Monensin sensitizes the delta psi level and the motility rate to low CCCP concentrations. The obtained data are consistent with the assumption that O. brevis possesses a primary Na+ pump which utilizes (directly or indirectly) the light energy.

Utilization of energy stored in the form of Na+ and K+ ion gradients by bacterial cells.

The hypothesis that Na+ and K+ gradients have an energy storing function [V. P. Skulachev (1978) FEBS Lett. 87, 171-176] has been tested in experiments with Escherichia coli, the marine bacterium Vibrio harveyi, an extremely halophilic Halobacterium halobium and a fresh-water cyanobacterium Phormidium uncinatum from Lake Baikal living at an extremely low salt concentration. The capability of these microorganisms to maintain delta microH was compared using motility as a delta microH-supported function. It was found that in all cases the gradient of monovalent cations is competent to prolong the period of active motility after other energy sources are exhausted. Maximal prolongation was found in H. halobium, which in a Na+ medium was still motile when light was switched off for 9 h under anaerobic conditions. In V. harveyi the motility was maintained for 1 h, in E. coli for about 10 min and in Ph. uncinatum for about 2 min. Thus the delta microH buffer capacity of the monovalent cation gradient is proportional to the content of these cations in the habitat. It was also found that in Ph. uncinatum only delta pK is effective, whereas in E. coli and V. harveyi both delta pK and delta pNa are. In E. coli when the K+ release is completed and the cells become motionless, motility can be temporarily restored by adding NaCl which initiates an H+ efflux. Under conditions of exhaustion of energy sources, the Na+ and K+ gradient was shown to stabilize potential in H. halobium cells, measured with a tetraphenylphosphonium probe. In H. halobium and E. coli, the anaerobic ATP level was found to stabilize when the Na+ and K+ gradients were present. Addition of N,N'-dicyclohexylcarbodiimide destabilized this level, which indicated that Na+ and K+ gradients could support de novo ATP synthesis. It is concluded that the data obtained are in agreement with the concept of the energy storing by the Na+ and K+ gradients. Other functions of these gradients and the mechanisms of their formation are discussed.

[Stabilization of delta mu H+ in Escherichia coli upon K+ and Na+ transmembrane gradient dissipation]. / Stabilizatsiia del'ta mu H+ i Escherichia coli pri rasseivanii transmembrannykh gradientov K+ i Na+.

The role of Na+/K+ gradients as a stabilizing factor for the energetics of bacterial cell has been evaluated. It was shown that in the presence of a Na+/K+ gradient across the membrane the cells of the unc mutant of E. coli retain their motility for some time under anaerobic conditions. This time coincides with that of dissipation of the K+ gradient by the bacteria during the anaerobiosis. A switch-off of the generator (respiration) entails a collapse of the membrane potential (delta psi). The anaerobiosis-induced efflux of K+ from the cells is uncoupler-stimulated, thus suggesting that the K+ efflux has an electrogenic nature and stabilizes delta psi. The use of valinomycin allowed to establish a correlation between the rate of K+ efflux, the delta psi value and the rate of bacterial motion under anaerobic conditions. After the onset of anaerobiosis the level of delta psi decreases faster as the concentration of extracellular K+ increases. It was shown that the capacity of the K+ gradient as te delta psi buffer depends on the pH of the medium and that artificial Na+ gradient can energize the E. coli cells by Na+/K+ exchange.