DMS dynamics in the most oligotrophic subtropical zones of the global ocean

The influences of physico-chemical and biological processes on dimethylsulfide (DMS) dynamics in the most oligotrophic subtropical zones of the global ocean were investigated. As metrics for the dynamics of DMS and the so-called ‘summer DMS paradox’ of elevated summer concentrations when surface chlorophyll a (Chl) and particulate organic carbon (POC) levels are lowest, we used the DMS-to-Chl and DMS-to-POC ratios in the context of three independent and complementary approaches. Firstly, field observations of environmental variables (such as the solar radiation dose, phosphorus limitation of phytoplankton and bacterial growth) were used alongside discrete DMS, Chl and POC estimates extracted from global climatologies (i.e., a ‘station based’ approach). We then used monthly climatological data for DMS, Chl, and POC averaged over the biogeographic province wherein a given oligotrophic subtropical zone resides (i.e., a ‘province based’ approach). Finally we employed sensitivity experiments with a new DMS module coupled to the ocean general circulation and biogeochemistry model PISCES to examine the influence of various processes in governing DMS dynamics in oligotrophic regions (i.e., a ‘model based’ approach). We find that the ‘station based’ and ‘province based’ approaches yield markedly different results. Interestingly, the ‘province based’ approach suggests the presence of a ‘summer DMS paradox’ in most all of the oligotrophic regions we studied. In contrast, the ‘station based’ approach suggests that the ‘summer DMS paradox’ is only present in the Sargasso Sea and eastern Mediterranean. Overall, we found the regional differences in the absolute and relative concentrations of DMS between 5 of the most oligotrophic regions of the world’s oceans were better accounted for by their nutrient dynamics (specifically phosphorus limitation) than by physical factors often invoked, e.g., the solar radiation dose. Our ‘model based’ experiments suggest that it is the limitation of phytoplankton/bacterial production and bacterial consumption of DMS by pervasive phosphorus limitation that is responsible for the ‘summer DMS paradox’.     

Glycerin supplementation strategies for three or seven days affects oxidative stress,follicle dynamics and ovulatory response in Morada Nova sheep

This study examined the effect of glycerin supply strategies in different short-term protocols on follicular dynamics and ovulatory rate in Morada Nova sheep. Eighteen Morada Nova ewes with body condition > 2.9 had their estrus and follicular waves synchronized using three injections of prostaglandin analogue at seven-day intervals. All animals received the same diet during 21 days, which consisted of a total mixed ration (TMR) based on chopped elephant grass and concentrate twice daily. In the control group (n=9), ewes were fed the TMR diet. In the other four groups, ewes received 150 mL of glycerol daily, supplied as an oral drench or mixed in the TMR during three or seven days prior to the application of the third PGF2 alfa analogue. These groups were named as follows: Drench3d (n=10), Drench7d (n=8), TMR3d (n=9) and TMR7d (n=9). Follicle dynamics were monitored by ultrasonography, and plasma glucose and glutathione peroxidase levels were measured at the third prostaglandin administration. Six days after the final PGF2 alfa analogue dose, ovulatory rate was measured by laparoscopy. Glucose was higher (P< 0.001) in the glycerin-treated groups than in control group (83.7 ± 1.7 vs. 68.4 ± 4.5 mg. dL^-1; P < 0.001). Ewes in the TMR3d, Drench7d and TMR7d groups had a greater (P < 0.001) number of large follicles (≥ 3 < 5 mm), and the presence of follicles larger than 5 mm was observed. In the same groups, at the third PGF2 alfa analogue dose, a greater (P < 0.001) number of growing follicles (> 3 mm) and a larger size of the largest follicle (P < 0.001) were also recorded. Ovulation rate was 30% higher in the groups that received glycerin for seven days (1.6 ± 0.1 53 vs. 1.1 ± 0.1; P < 0.05), and they also exhibited a 38% reduction in glutathione peroxidase. Thus, the use of glycerin in Morada Nova sheep as a source of energy in short-term supplementation for increase ovulation rate is an efficient strategy when provided for seven days, either orally or in the feed.     

Intrastriatal administration of human immunodeficiency virus‐1 glycoprotein 120 reduces glial cell‐line derived neurotrophic factor levels and causes apoptosis in the substantia nigra

Uninfected neurons of the substantia nigra (SN) degenerate in human immunodeficiency virus (HIV)‐positive patients through an unknown etiology. The HIV envelope glycoprotein 120 (gp120) causes apoptotic neuronal cell death in the rodent striatum, but its primary neurotoxic mechanism is still under investigation. Previous studies have shown that gp120 causes neurotoxicity in the rat striatum by reducing brain‐derived neurotrophic factor (BDNF). Because glial cell line‐derived neurotrophic factor (GDNF) and BDNF are neurotrophic factors crucial for the survival of dopaminergic neurons of the SN, we investigated whether gp120 reduces GDNF and BDNF levels concomitantly to induce apoptosis. Rats received a microinjection of gp120 or vehicle into the striatum and were sacrificed at various time intervals. GDNF but not BDNF immunoreactivity was decreased in the SN by 4 days in gp120‐treated rats. In these animals, a significant increase in the number of caspase‐3‐ positive neurons, both tyrosine hydroxylase (TH)‐positive and ‐negative, was observed. Analysis of TH immunoreactivity revealed fewer TH‐positive neurons and fibers in a medial and lateral portion of cell group A9 of the SN, an area that projects to the striatum, suggesting that gp120 induces retrograde degeneration of nigrostriatal neurons. We propose that dysfunction of the nigrostriatal dopaminergic system associated with HIV may be caused by a reduction of neurotrophic factor expression by gp120. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006     

Peg-Interferon Plus Ribavirin with or without Boceprevir or Telaprevir for HCV Genotype 1: A Meta-Analysis on the Role of Response Predictors

Background & aim

To compare the efficacy of pegylated-interferon (Peg-IFN) α-2a or α-2b and ribavirin given as dual therapy versus triple therapy (Peg-IFN and ribavirin plus boceprevir or telaprevir) in patients with HCV-1 chronic hepatitis naïve for anti-HCV therapy or relapsers to dual therapy in relation to the presence of constitutional, clinical and virological predictors of treatment response.

Methods

Included in the meta-analysis were studies meeting these criteria: original data from randomized trials on the efficacy of dual versus triple therapy in therapy-naïve patients or relapsers; at least one primary outcome clearly defined: sustained virological response in patients with or without rapid virological response (RVR), with genotype 1a or 1b, low or high HCV load, IL28-B CC or non-CC genotype, mild or severe fibrosis; odds ratio estimates of relative risk (RR) and 95% confidence intervals; English language; and published up to the end of June 2013.

Results

Seven original studies met the inclusion criteria, allowing a meta-analysis on 3,652 patients. Triple therapy was more effective than dual, regardless of IL-28B genotype, HCV sub-genotype, liver fibrosis, and baseline HCV load. In 1,045 patients who achieved RVR, SVR was more frequently achieved with dual therapy (RR = 1.11; p = 0.002) than triple. The same results were achieved when only the therapy-naïve patients were considered.

Conclusions

Triple therapy provides a significantly higher SVR rate than dual therapy, but dual therapy obtains a significantly higher SVR rate in patients with RVR. The data stress the clinical importance of a 4-week lead-in phase in direct-acting antiviral-based treatment.     

Inhibition of mitochondrial substrate anion translocators by a synthetic amphipathic polyanion

A synthetic polyanion (a copolymer of methacrylate, maleate, and styrene in 1:2:3 proportion with an average molecular weight of 10,000 dalton) inhibits the tricarboxylate, oxoglutarate, dicarboxylate, and adenine nucleotide translocators of rat liver mitochondria. The activity versus inhibitor concentration curves are sigmoidal. The inhibition of the oxoglutarate and tricarboxylate translocators by the polyanion is competitive, while that of the adenine nucleotide translocator is of mixed-type. TheK ₁ values of the polyanion are the following: for oxoglutarate translocator 4.0 µM, tricarboxylate translocator 1.2 µM, and adenine nucleotide translocator 1.3 µM with ADP and 0.8 µM with ATP. It is suggested that the polyanion acts primarily by increasing the negative charge of the inner membrane at the outer surface, and the sensitivity of the translocators toward the polyanion depends on the number of negative charges of their substrates.     

Potential of a granulovirus isolate to control <Emphasis Type="Italic">Phthorimaea operculella</Emphasis> (Lepidoptera: Gelechiidae)

In this study a Brazilian granulovirus strain, PhopGV, isolated from the potato tuber moth (PTM) Phthorimaea operculella, was investigated regarding its potential for biological control and in vivo production. The relationship between mortality of P. operculella larvae and virus concentration was determined at different temperatures on potato tubers and susceptibility of P. operculella to PhopGV was also determined on potato leaves. Virulence of PhopGV to P. operculella was not affected by temperatures from 18 to 30°C. The median lethal concentration (LC₅₀) of larvae fed on potato foliage treated with PhopGV was not higher than that verified with larvae fed on treated tubers. Optimal conditions for production of virus-infected larvae were obtained by using the virus suspensions of 41 × 10⁵, 6.3 × 10⁵ and 62 × 10⁵ OBs ml⁻¹ at 18, 24 and 30°C, which resulted in 32.0, 31.4 and 34.8% of infected larvae collected, respectively. The maximum percentage of infected larvae recovered from tubers was not affected by temperature. However, time for production of virus-infected larvae was longer at 18°C and shorter at 30°C. Persistence of PhopGV was determined on stored tubers and we observed that the virus remained effective for at least two months, causing up to 84.2% mortality of P. operculella at 1 × 10⁷ OBs ml⁻¹. The pathogen was also highly virulent to tomato pinworm, Tuta absoluta, inflicting high percentage of mortality, delaying larval growth and inhibiting pupation. This Brazilian PhopGV strain has potential to control PTM larvae on potato tubers at a broad range of temperature and can be produced in vivo using virus-treated tubers.     

Use of Cystatin C and Serum Creatinine for the Diagnosis of Contrast-Induced Nephropathy in Patients Undergoing Contrast-Enhanced Computed Tomography at an Oncology Centre

ObjectiveOur aim was to assess renal function using as laboratory measurements serum creatinine and cystatin C concentrations before and after administration of low-osmolarity (nonionic) iodinated contrast medium in patients with cancer undergoing computed tomography (CT).MethodsThis prospective study included 400 oncologic outpatients. Serum creatinine and cystatin C concentrations were measured before and 72 h after contrast administration. Glomerular filtration rates (GFRs) were estimated using serum creatinine–based [Modification of Diet in Renal Disease (MDRD) and Cockroft-Gault and cystatin C based (Larsson) equations. Exploratory data analysis was performed. The nonparametric Wilcoxon test was used to compare pre and post contrast of test results and estimated clearance. The confidence interval used in the analysis was 95%.ResultsCompared with the pre-contrast values, the mean serum creatinine concentration was significantly higher and average GFRs estimated using MDRD and Cockcroft-Gault equations were significantly lower after the administration of contrast (p <0.001). It was also observed a significant increase after contrast in the concentration of Cystatin C (p = 0.015). In addition, a decrease in GFR estimated using the average Larsson (p = 0.021) was observed between time points. However, none of the patients presented clinically significant nephropathy.ConclusionsAssessment using serum creatinine and cystatin C concentrations showed changes in renal function among patients with cancer undergoing contrast-enhanced CT examination in this study. No significant renal damage related to the use of low-osmolarity iodinated contrast medium of the type and dosage employed in this study was observed. This contrast medium is thus safe for use in patients with cancer.     

1H and 13c nmr analysis of lycorine and α-dihydrolycorine

-The ¹H and ¹³C NMR spectra of lycorine and its α-dihydro derivative have been studied. The employment of nuclear magnetic double resonance, nuclear Overhauser effect and acetylated derivatives, allows the assignment of all proton resonances. The assignments of the carbon shifts have been obtained by means of proton noise decoupled, single frequency off-resonance decoupled, single frequency selective decoupling, time dependence nuclear Overhauser effect and by comparison with reference compounds.