The Group IV phospholipase A2 family is comprised of six intracellular enzymes commonly called cytosolic phospholipase A2 (cPLA2) alpha, cPLA2beta, cPLA2gamma, cPLA2delta, cPLA2epsilon and cPLA2zeta. ...They are most homologous to phospholipase A and phospholipase B/lysophospholipases of filamentous fungi particularly in regions containing conserved residues involved in catalysis. However, a number of other serine acylhydrolases (patatin, Group VI PLA2s, Pseudomonas aeruginosa ExoU and NTE) contain the Ser/Asp catalytic dyad characteristic of Group IV PLA2s, and recent structural analysis of patatin has confirmed its structural similarity to cPLA2alpha. A characteristic of all these serine acylhydrolases is their ability to carry out multiple reactions to varying degrees (PLA2, PLA1, lysophospholipase and transacylase activities). cPLA2alpha, the most extensively studied Group IV PLA2, is widely expressed in mammalian cells and mediates the production of functionally diverse lipid products in response to extracellular stimuli. It has PLA2 and lysophospholipase activities and is the only PLA2 that has specificity for phospholipid substrates containing arachidonic acid. Because of its role in initiating agonist-induced release of arachidonic acid for the production of eicosanoids, cPLA2alpha activation is important in regulating normal and pathological processes in a variety of tissues. Current information available about the biochemical properties and tissue distribution of other Group IV PLA2s suggests they may have distinct mechanisms of regulation and functional roles.
Cattle manure from stock bedded on straw was aerobically composted under ambient conditions, turning with either a tractor-mounted front-end loader or a rear discharge manure spreader. Three ...composting experiments, each of approximately four months duration, were conducted to investigate the effect of turning regime and seasonal weather conditions on nitrogen and phosphorus losses during aerobic composting of cattle manure. Manure stacks of 12–15 m
3 initial volume were constructed in separate 5
×
5 m concrete compartments. Experiment 1 (January–April 1999) compared manure heaps turned once (T1) or three times (T3) using a front-end loader with an unturned static (S) control manure stack. Experiment 2 (June–September 1999) compared the same treatments as Experiment 1. Experiment 3 (September–December 1999) compared T1 and T3 turning regimes using a front end loader with turning by a rear-discharge spreader (TR1 and TR1T2) for more effective aeration of the manure. Turning took place at 6 weeks for the one turn treatments, and after 2, 6 and 10 weeks for the three turn treatments.
Leachate losses were dominated by NH
4-N during the first three weeks of composting, after which time NH
4-N and NO
3-N concentrations in leachates were approximately the same, in the range 0–20 mg
N
l
−1. The concentrations of both NH
4-N and NO
3-N in leachate were higher after turning. Molybdate-reactive P concentrations in leachate tended not to be significantly influenced by turning regime. Gaseous losses of NH
3 and N
2O rose quickly during the initial phases of composting, peaking at 152 g
N
t
−1
d
−1 for the T3 treatment. Mean NH
3 emission rate (25–252 g
N
t
−1
d
−1) for the first two weeks of Experiment 2 conducted during the period June–September were an order of magnitude greater (1–10 g
N
t
−1
d
−1) than Experiment 3, conducted during the colder, wetter autumn period (September–December). Nitrous oxide emission rates ranged between 1–14 g
N
t
−1
d
−1 and showed little influence of turning regime. Total N and P concentrations in turned (T) and static (S) manure were elevated at the end of all experiments, due to loss of dry matter. Mean total N losses were 30.4% (T1) and 36.8% (T3) and total P losses 28.2% (T1) and 27.4% (T3).
Background. Lack of life-long immunity against influenza viruses represents a major global health care problem with profound medical and economic consequences. A greater understanding of the ...broad-spectrum "heterosubtypic" neutralizing human antibody (BnAb) response to influenza should bring us closer toward a universal influenza vaccine. Methods. Serum samples obtained from 77 volunteers in an H5N1 vaccine study were analyzed for cross-reactive antibodies (Abs) against both subtype hemagglutinins (HAs) and a highly conserved pocket on the HA stem of Group 1 viruses. Cross-reactive Abs in commercial intravenous immunoglobulin were affinity purified using H5-coupled beads followed by step-wise monoclonal antibody competition or acid elution. Enzyme-linked immunosorbent assays were used to quantify cross-binding, and neutralization activity was determined with HA-pseudotyped viruses. Results. Prevaccination serum samples have detectable levels of heterosubtypic HA binding activity to both Group 1 and 2 influenza A viruses, including subtypes H5 and H7, respectively, to which study subjects had not been vaccinated. Two different populations of Broadly neutralizing Abs (BnAbs) were purified from intravenous immunoglobulin by H5 beads: ∼0.01% of total immunoglobulin G can bind to HAs from both Group 1 and 2 and neutralize H1N1 and H5N1 viruses; ∼0.001% is F10-like Abs directed against the HA stem pocket on Group 1 viruses. Conclusions. These data—to our knowledge, for the first time—quantitatively show the presence, albeit at low levels, of two populations of heterosubtypic BnAbs against influenza A in human serum. These observations warrant further investigation to determine their origin, host polymorphism(s) that may affect their expression levels and how to boost these BnAb responses by vaccination to reach sustainable protective levels.
Objectives
Tenofovir disoproxil fumarate (TDF) is increasingly used in the highly active antiretroviral therapy (HAART) regimens of pregnant women, but limited data exist on the pregnancy ...pharmacokinetics of chronically dosed TDF. This study described tenofovir pharmacokinetics during pregnancy and postpartum.
Methods
International Maternal Pediatric and Adolescent AIDS Clinical Trials (IMPAACT) P1026s is a prospective, nonblinded pharmacokinetic study of HIV‐infected pregnant women that included a cohort receiving 300 mg TDF once daily. Steady‐state 24‐hour pharmacokinetic profiles were measured at the second and third trimesters, postpartum, and in maternal and umbilical cord samples collected at delivery. Tenofovir was measured by liquid chromatography−mass spectrometry (LC‐MS). The target area under the concentration versus time curve from time 0 to 24 h post dose (AUC) was ≥ 1.99 μg h/mL (nonpregnant historical control 10th percentile).
Results
The median tenofovir AUC was decreased during the second (1.9 μg h/mL) and third (2.4 μg h/mL; P = 0.005) trimesters versus postpartum (3.0 μg h/mL). Tenofovir AUC exceeded the target for two of four women (50%) in the second trimester, 27 of 37 women 73%; 95% confidence interval (CI) 56%, 86% in the third trimester, and 27 of 32 women (84%; 95% CI 67%, 95%) postpartum (P > 0.05). Median second/third‐trimester troughs were lower (39/54 ng/mL) than postpartum (61 ng/mL). Median third‐trimester weight was greater for subjects below the target AUC versus those above the target (97.9 versus 74.2 kg, respectively; P = 0.006). The median ratio of cord blood to maternal concentrations was 0.88. No infants were HIV infected.
Conclusions
This study found lower tenofovir AUC and troughs during pregnancy. Transplacental passage with chronic TDF use during pregnancy was high. Standard TDF doses appear to be appropriate for most HIV‐infected pregnant women but therapeutic drug monitoring with dose adjustment should be considered in pregnant women with high weight (> 90 kg) or inadequate HIV RNA response.
Members of the newly discovered regulator of G protein signaling (RGS) families of proteins have a common RGS domain. This RGS domain is necessary for conferring upon RGS proteins the capacity to ...regulate negatively a variety of Galpha protein subunits. However, RGS proteins are more than simply negative regulators of signaling. RGS proteins can function as effector antagonists, and recent evidence suggests that RGS proteins can have positive effects on signaling as well. Many RGS proteins possess additional C- and N-terminal modular protein-binding domains and motifs. The presence of these additional modules within the RGS proteins provides for multiple novel regulatory interactions performed by these molecules. These regions are involved in conferring regulatory selectivity to specific Galpha-coupled signaling pathways, enhancing the efficacy of the RGS domain, and the translocation or targeting of RGS proteins to intracellular membranes. In other instances, these domains are involved in cross-talk between different Galpha-coupled signaling pathways and, in some cases, likely serve to integrate small GTPases with these G protein signaling pathways. This review discusses these C- and N-terminal domains and their roles in the biology of the brain-enriched RGS proteins. Methods that can be used to investigate the function of these domains are also discussed.
Objectives
Pregnancy results in physiological changes altering the pharmacokinetics of drugs metabolized by cytochrome P450 3A4 (CYP3A4). The urinary ratio of 6‐β hydroxycortisol to cortisol (6βHF : ...F) is a marker of CYP3A4 induction. We sought to evaluate its change in antiretroviral (ARV)‐treated HIV‐1‐infected women and to relate this change to ARV pharmacokinetics.
Methods
Women receiving various ARVs had pharmacokinetic evaluations during the third trimester of pregnancy (> 30 weeks) and postpartum with determination of 6βHF : F carried out on the same days. The Wilcoxon signed rank test was used to compare the ratio antepartum to postpartum. The relationship between the change in ratio and the change in pharmacokinetics was analysed using Kendall's tau.
Results
6βHF : F ratios were available for 107 women antepartum, with 54 having postpartum values. The ratio was higher antepartum (P = 0.033) (median comparison 1.35; 95% confidence interval 1.01, 1.81). For 71 women taking a protease inhibitor (PI), the antepartum vs. postpartum 6βHF : F comparison was marginally significant (P = 0.058). When the change in the 6βHF : F ratio was related to the change in the dose‐adjusted ARV area under the plasma concentration vs. time curve (AUC) between antepartum and postpartum, the 35 subjects in the lopinavir/ritonavir (LPV/r) arms demonstrated an inverse relationship (P = 0.125), albeit this correlation did not reach statistical significance.
Conclusions
A 35% increase in the urinary 6βHF : F ratio was measured during late pregnancy compared with postpartum, indicating that CYP3A induction occurs during pregnancy. The trend towards an inverse relationship between the change in the 6βHF : F ratio and the change in the LPV AUC antepartum vs. postpartum suggests that CYP3A induction may be one mechanism behind altered LPV exposure during pregnancy.
Cerebrospinal fluid (CSF) specimens from 77 neonates with herpes simplex virus (HSV) disease were evaluated retrospectively by polymerase chain reaction (PCR). Samples were collected from 202 infants ...enrolled in a National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group trial that compared vidarabine with acyclovir for the treatment of neonatal HSV infection. HSV DNA was detected in the CSF of 26 (76%) of 34 infants with CNS disease, in 13 (93%) of 14 infants with disseminated infection, and in 7 (24%) of 29 with skin, eye, or mouth (SEM) involvement. One of the 7 PCR~positive SEM patients subsequently developed severe neurologic impairment. Eighteen (95%) of 19 infants with positive CSF PCR results after the completion of 10 days of antiviral therapy experienced significant morbidity or mortality. Application of PCR to neonatal HSV disease may provide additional information on which clinical decisions may be based, although its diagnostic utility outside the research setting is unproven.
Background
Pregnancy may alter protein binding (PB) of highly bound protease inhibitors due to changes in plasma concentrations of albumin and α‐1 acid glycoprotein (AAG). Small changes in PB can ...greatly impact the fraction of drug unbound (FU) exerting pharmacological effect. We report lopinavir (LPV) PB during third trimester (antepartum, AP) compared to ≥1.7 weeks postpartum (PP) to determine if FU changes compensate for reduced total concentrations reported previously.
Methods
P1026s enrolled women receiving LPV/ritonavir, soft gel capsules 400/100 mg or 533/133 mg twice daily. LPV FU, albumin and AAG were determined AP and PP.
Results
AP/PP samples were available from 29/25 women respectively with all but one woman receiving the same dose AP/PP. LPV FU was increased 18% AP vs. PP (mean 0.96±0.16% AP vs. 0.82±0.21% PP, P=0.001). Mean protein concentrations were reduced AP (AAG=477 mg/L; albumin=3.28 mg/dL) vs. PP (AAG=1007 mg/L; albumin=3.85 mg/dL) (P<0.0001 for each comparison). AAG concentration correlated with LPV binding. Total LPV concentration did not correlate with LPV FU AP or PP. However, higher LPV concentration PP was associated with reduced PB and higher FU after adjustment for AAG.
Conclusions
LPV FU was higher and AAG lower AP vs. PP. The 18% increase in LPV FU AP is smaller than the reduction in total LPV concentration reported previously and is not of sufficient magnitude to eliminate the need for an increased dose during pregnancy.
Background. The safety and immunogenicity of high-dose pandemic H1N1 (pH1N1) vaccination in perinatally human immunodeficiency virus type 1 (HIV-1)—infected children, adolescents, and young adults ...are unknown. Methods. Two 30-μg doses of 2009 Novartis pH1N1 monovalent vaccine (Fluvirin) were administered 21—28 days apart to perinatally HIV-1—infected children, adolescents, and young adults. Antibodies were measured by hemagglutination inhibition (HAI) assay at baseline, 21—28 days after first vaccination, 7—13 days after the second vaccination, and 7 months after the first vaccination. Results. Among the 155 participants, 54 were aged 4—8 years, 51 were aged 9—17 years, and 50 were aged 18—24 years. After 2 doses of Fluvirin, seroresponse (≥4-fold rise in HAI titers) was demonstrated in 79.6%, 84.8%, and 83% of participants in the aforementioned age groups, respectively, and seroprotection (HAI titers ≥40) was shown in 79.6%, 82.6%, and 85.1%, respectively. Of those lacking seroresponse (n = 43) or seroprotection (n = 37) after the first vaccination, 46.5% and 40.5% achieved seroresponse or seroprotection, respectively, after the second vaccination. Among participants who lacked seroprotection at entry, a "complete response" (both seroresponse and seroprotection) after first vaccination was associated with higher baseline log 10 HAI titer and non-Hispanic ethnicity. No serious vaccine-related events occurred. Conclusion. Two doses of double-strength pH1N1 vaccine are safe and immunogenic and may provide improved protection against influenza in perinatally HIV-1—infected children and youth. Clinical Trials Registration. NCT00992836.
Increasing evidence indicates that potent anti-HIV-1 activity is mediated by cytotoxic T lymphocytes (CTLs); however, the effects of this immune pressure on viral transmission and evolution have not ...been determined. Here we investigate mother-child transmission in the setting of human leukocyte antigen (HLA)-B27 expression, selected for analysis because it is associated with prolonged immune containment in adult infection. In adults, mutations in a dominant and highly conserved B27-restricted Gag CTL epitope lead to loss of recognition and disease progression. In mothers expressing HLA-B27 who transmit HIV-1 perinatally, we document transmission of viruses encoding CTL escape variants in this dominant Gag epitope that no longer bind to B27. Their infected infants target an otherwise subdominant B27-restricted epitope and fail to contain HIV replication. These CTL escape variants remain stable without reversion in the absence of the evolutionary pressure that originally selected the mutation. These data suggest that CTL escape mutations in epitopes associated with suppression of viraemia will accumulate as the epidemic progresses, and therefore have important implications for vaccine design.
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