S-glutathionylation, friend or foe in cardiovascular health and disease.

Glutathione is a low molecular weight thiol that is present at high levels in the cell. The high levels of glutathione in the cell make it one of the most abundant antioxidants contributing to cellular redox homeostasis. As a general rule, throughout cardiovascular disease and progression there is an imbalance in redox homeostasis characterized by reactive oxygen species overproduction and glutathione underproduction. As research into these imbalances continues, glutathione concentrations are increasingly being observed to drive various physiological and pathological signaling responses. Interestingly in addition to acting directly as an antioxidant, glutathione is capable of post translational modifications (S-glutathionylation) of proteins through both chemical interactions and enzyme mediated events. This review will discuss both the chemical and enzyme-based S-glutathionylation of proteins involved in cardiovascular pathologies and angiogenesis.

Hydrogen sulfide: Therapeutic or injurious in ischemic stroke?

Hydrogen sulfide (H2S) has been identified as a vasodilatory, neuromodulatory, and anti-inflammatory gasotransmitter with antioxidant properties. Studies focused in cardiac tissue suggest H2S functions as a protective agent; however in the central nervous system (CNS) the effects of H2S during states of stress or injury, such as stroke, remain controversial. Currently, the application of H2S donors and modulators in stroke depends on the type of H2S donor and the timing of the therapy.

Molecular mimicry in inducing DNA damage between HIV-1 Vpr and the anticancer agent, cisplatin.

The human immunodeficiency virus type 1 (HIV-1) viral protein R (vpr) gene is an evolutionarily conserved gene among the primate lentiviruses. Several functions are attributed to Vpr including the ability to cause cell death, cell cycle arrest, apoptosis and DNA damage. The Vpr domain responsible for DNA damage as well as the mechanism(s) through which Vpr induces this damage is unknown. Using site-directed mutagenesis, we identified the helical domain II within Vpr (aa 37-50) as the region responsible for causing DNA damage. Interestingly, Vpr Delta(37-50) failed to cause cell cycle arrest or apoptosis, to induce Ku70 or Ku80 and to suppress tumor growth, but maintained its capability to activate the HIV-1 LTR, to localize to the nucleus and to promote nonhomologous end-joining. In addition, our cytogenetic data indicated that helical domain II induced chromosomal aberrations, which mimicked those induced by cisplatin, an anticancer agent. This novel molecular mimicry function of Vpr might lead to its potential therapeutic use as a tumor suppressor.

A randomized controlled trial of the effect of increased intravenous hydration on the course of labor in nulliparous women.

OBJECTIVE: One variable that has the potential to affect the course of labor but has not been evaluated previously is the adequacy of maternal hydration. Typical orders provide for 125 mL of intravenous fluids per hour in patients taking limited oral fluids. Many such patients are clinically dehydrated. Physiologists have shown that increased fluids improve skeletal muscle performance in prolonged exercise. This study was designed to determine whether increased intravenous fluids affect the progress of labor. STUDY DESIGN: Nulliparous women with uncomplicated singleton gestations at term, in spontaneous active labor with dilatation between 2 and 5 cm, and with a cephalic presentation were included. Patients who gave consent were randomly selected to receive either 125 mL or 250 mL of intravenous fluids per hour. RESULTS: One hundred ninety-five patients were randomly selected, 94 to the 125-mL group and 101 to the 250-mL group. Prerandomization variables were well matched between the 2 groups. The mean volume of total intravenous fluids was significantly greater in the 250-mL group (2008 mL vs 2487 mL; P =.002), as was the mean hourly rate (152 mL/h in the 125-mL group vs 254 mL/h in the 250-mL group; P =.001). The frequency of labor lasting >12 hours was statistically higher in the 125-mL group (20/78 [26%] vs 12/91 [13%]; P =.047). In addition, there was a trend favoring longer mean duration of the first stage and total duration of labor in patients delivered vaginally in the 125-mL group, by 70 and 68 minutes, respectively (P =.06). There was a trend toward a lower frequency of oxytocin administration for inadequate labor progress in the higher fluid rate group (61 [65%] in the 125-mL group vs 51 [49%] in the 250-mL group; P =.06). Cesarean deliveries were more frequent in the 125-mL group (n = 16) than in the 250-mL group (n = 10) but did not reach statistical significance. CONCLUSION: This study presents the novel finding that increasing fluid administration for nulliparous women in labor above rates commonly used is associated with a lower frequency of prolonged labor and possibly less need for oxytocin. Thus inadequate hydration in labor may be a factor contributing to dysfunctional labor and possibly cesarean delivery. Consideration of this factor in clinical management and in future studies considering variables that affect labor is warranted.

Landsat image and sample design for water reservoirs (Rapel dam Central Chile).

Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys.

[Digital image processing: fundamental techniques and applications in biological research]. / Procesamiento de imágenes digitales: técnicas fundamentales y aplicaciones en la investigación en biología.

Digital image processing represents a relatively new but very dynamic domain. Its importance is still growing due to the rapid development in related computer equipment. In this paper basics concepts are introduced and a survey of problems and methods is presented. Starting with techniques used for the capture of data, it continues with techniques applied to coding new data, image enhancement and pattern recognition. Special attention is given to pattern recognition techniques which provide the basics for classification of data according to established criteria. Finally, two applications are presented; the reconstruction of 3-D volumes from serial cutting and a survey of chlorophyll concentration on Lake Aculeo using remote images obtained by the LANDSAT satellite.