Understanding the pharmacokinetics of Coartem®

Background

During pregnancy, women are more susceptible to Plasmodium falciparum infections and frequently have a higher parasitaemia than non-pregnant women. Several mechanisms are responsible for their increased susceptibility, including down-modulation of immune responses that aid in parasite clearance and sequestration of infected erythrocytes in the placenta. Early in pregnancy, a third mechanism may contribute to higher parasitaemia, since it has been reported that addition of human chorionic gonadotropin (hCG) to in vitro cultures of the NF54-strain of P. falciparum results in increased parasite growth rates. The goal of this study was to further examine the effect of hCG on P. falciparum growth.

Methods

The NF54-3D7, FVO and 7G8 strains of P. falciparum were cultured in vitro with various physiological concentrations of hCG purchased from three sources. Infected erythrocytes were also co-cultured with a human cell line that naturally secretes hCG.

Results

Results from 14 experiments using different combinations of parasite strains and concentrations of hCG from different sources, as well as the co-culture studies, failed to provide convincing evidence that hCG enhances parasite growth in vitro.

Conclusion

Based on these data, it seems unlikely that hCG has a direct effect on the rate of parasite growth early in pregnancy.     

Safety of the production process of SURFACEN® to inactivate and remove virus

SURFACEN^® is a biological product produced from pig lungs. Since these animals can be potential sources of microbial pathogens such as viruses, the manufacturing process of this product should guarantee safety from health hazards. The SURFACEN^® production procedure is capable of effective viral clearance (inactivation/removal) by involving two stages of organic solvent extraction followed by acetone precipitation and heat treatment. In this study, we evaluated the clearance capacity of these four stages for a wide range of viruses by performing spiking experiments. Residual contamination was assessed using a Tissue Culture Infectious Dose assay (log₁₀ TCID₅₀). The validation study demonstrated that, for all viruses tested, the TCID₅₀ titers were reduced by more than 2 log₁₀ in each stage. Total log reduction values achieved were between ≥17.82 log₁₀ and ≥27.93 log₁₀, depending on the virus physical properties, titer, and the number of processing stages applied. Results indicated that the production procedure of SURFACEN^® can inactivate or remove contaminant viruses from the raw material.     

Glycosylation profile and biological activity of Remicade® compared with Flixabi® and Remsima®

As biosimilars enter the market, comparisons of product quality are needed. Manufacturing differences may lead to differences in critical quality attributes, which affect efficacy. Therefore, critical quality attributes (structure and biological activity) of Remicade® and of 2 biosimilar products (Flixabi®/Renflexis® and Remsima®/Inflectra®) were determined. We assessed binding to tumor necrosis factor in a fluorescence competitive binding assay; potency in a luciferase reporter gene assay; percentages of galactosylated glycan, afucose plus high mannosylated glycans, and charged glycan; FcγRIIIa (CD16) binding (assessed by 3 methods); and antibody-dependent cell-mediated cytotoxicity (ADCC) in the NK92-CD16a cell line and in peripheral blood mononuclear cells (PBMC). The results of Fab-related activity were similar for all products. Compared with Remicade®, Flixabi® had a lower percentage of charged glycan, and Remsima® had a higher percentage of galactosylated glycan and a lower percentage of afucose plus high mannosylated glycans. Whereas Remsima® and Remicade® are expressed in a Sp2/0 cell line, Flixabi® is expressed in a CHO cell line. Despite this difference, galactosylated glycans from the 3 products were not correlated with the expression system. The results of all 3 methods used in this study indicated that FcγRIIIa binding was lower with Remsima® than with Remicade®. The percentage of ADCC in NK92-CD16a cells was lower with Remsima® and higher with Flixabi® compared with Remicade®, but was similar for all 3 products in PBMC. Surface expression of CD16 was 5.7-fold greater on NK92-CD16a cells than on PBMC. Combined percentages of afucosylated and high mannosylated glycans were positively correlated with FcγRIIIa binding and ADCC in NK92-CD16 cells, while no correlation was observed in PBMC.     

A restatement of the natural science evidence base relevant to the control of bovine tuberculosis in Great Britain?

Bovine tuberculosis (bTB) is a very important disease of cattle in Great Britain, where it has been increasing in incidence and geographical distribution. In addition to cattle, it infects other species of domestic and wild animals, in particular the European badger (Meles meles). Policy to control bTB is vigorously debated and contentious because of its implications for the livestock industry and because some policy options involve culling badgers, the most important wildlife reservoir. This paper describes a project to provide a succinct summary of the natural science evidence base relevant to the control of bTB, couched in terms that are as policy-neutral as possible. Each evidence statement is placed into one of four categories describing the nature of the underlying information. The evidence summary forms the appendix to this paper and an annotated bibliography is provided in the electronic supplementary material.     

Hormetic effects of curcumin: What is the evidence?

Curcumin (diferuloylmethane), a component of the yellow powder prepared from the roots of Curcuma longa or Zingiberaceae (known as turmeric) is not only widely used to color and flavor food but also used as a pharmaceutical agent. Curcumin demonstrates anti-inflammatory, anticarcinogenic, antiaging, and antioxidant activity, as well as efficacy in wound healing. Notably, curcumin is a hormetic agent (hormetin), as it is stimulatory at low doses and inhibitory at high doses. Hormesis by curcumin could be also a particular function at low doses (i.e., antioxidant behavior) and another function at high dose (i.e., induction of autophagy and cell death). Recent findings suggest that curcumin exhibits biphasic dose–responses on cells, with low doses having stronger effects than high doses; examples being activation of the mitogen-activated protein kinase signaling pathway or antioxidant activity. This indicates that many effects induced by curcumin are dependent on dose and some effects might be greater at lower doses, indicative of a hormetic response. Despite the consistent occurrence of hormetic responses of curcumin in a wide range of biomedical models, epidemiological and clinical trials are needed to assess the nature of curcumin’s dose–response in humans. Fortunately, more than one hundred clinical trials with curcumin and curcumin derivatives are ongoing. In this review, we provide the first comprehensive analysis supportive of the hormetic behavior of curcumin and curcumin derivatives.     

DNA profile of the spore of blastocladiella emersonii: Evidence for γ-particle DNA

Summary Procedures were developed for isolating DNA from zoospores of Blastocladiella emersonii, critical steps being the use of non-frozen cells, enzymatic elimination of polysaccharide, and a combined treatment with T₁RNAse and pancreatic RNAse for complete removal of RNA. Methods for isolating -particles from spores were also established. Extraction of DNA directly from purified -particles substantiated previous assumptions that they contain DNA. Heat denaturation and preparative CsCl equilibrium sedimentation studies of whole spore DNA revealed the presence of four distinct components, I–IV, with buoyant densities of 1.731, 1.715, 1.705, and 1.687 g/cm³. The major species appeared to be nuclear chromatin. Nucleolar and mitochondrial sites were tentatively assigned to species II and III, respectively. Evidence was presented that species IV resided in -particles. Some possible roles for -particle DNA were discussed.Abbreviations EGTA ethyleneglycol-bis (B-aminoethyl ether)-N,N-tetracetic acid - EDTA ethylenediaminetetracetic acid - TCA trichloroacetic acid - SDS sodium dodecyl sulfate - SSC 0.15 M NaCl and 15 mM Na citrate     

Phototautomerism of the GC base pair of DNA

Electronic spectra and ground and excited state electronic structures of normal G and rare tautomeric G1z.sbnd;C1 base pairs as well as of the individual rare tautomeric bases (purines and pyrimidines) have been studied using the VE-PPP molecular orbital method. The nature and consequences of the lowest energy purine-localized and purine to pyrimidine charge transfer type π?π1 singlet excitations of the base pairs have been investigated. The results indicate that in these excited states, particularly in the charge transfer excited state, the probability for the GC base pair to change over to G1C1 would be larger than in the ground state. The likeliness of the relevance of results obtained experimentally by other workers from the study of a model system to the GC base pair is discussed.     

What is not a bird of paradise? Molecular and morphological evidence places Macgregoria in the Meliphagidae and the Cnemophilinae near the base of the corvoid tree.

The cnemophiline 'birds of paradise' (Cnemophilinae) and Macgregor's 'bird of paradise' (Macgregoria) have traditionally been included in the Paradisaeidae although their relationships within the group have been enigmatic and subject to repeated discussion in the literature. Here we use sequences from two mitochondrial genes, cytochrome b and cytochrome oxidase I, along with a suite of morphological characters, to investigate their relationships to paradisaeids and other members of the passerine Parvorder Corvida. The combined data strongly support the removal of both groups from the birds of paradise: the cnemophilines are basal members of the Corvoidea and Macgregoria is a member of the Meliphagoidea and embedded in the honeyeaters (Meliphagidae) close to the genus Melipotes. The amount of sequence divergence among basal passeriforms and members of the Corvida, as well as available fossil evidence for Australian corvidans, suggest that cnemophilines represent an ancient lineage within the corvoid radiation. Because cnemophilines and Macgregoria have been placed at the base of the paradisaeid tree, hypotheses of morphological, behavioural and ecological character-state transformations within the family will require reanalysis.     

Hydrogen bonding to the cysteine ligand of superoxide reductase: acid–base control of the reaction intermediates

Superoxide reductase (SOR) is a non-heme iron metalloenzyme that detoxifies superoxide radical in microorganisms. Its active site consists of an unusual non-heme Fe²⁺ center in a [His₄Cys₁] square pyramidal pentacoordination, with the axial cysteine ligand proposed to be an essential feature in catalysis. Two NH peptide groups from isoleucine 118 and histidine 119 establish hydrogen bonds involving the sulfur ligand (Desulfoarculus baarsii SOR numbering). To investigate the catalytic role of these hydrogen bonds, the isoleucine 118 residue of the SOR from Desulfoarculus baarsii was mutated into alanine, aspartate, or serine residues. Resonance Raman spectroscopy showed that the mutations specifically induced an increase of the strength of the Fe³⁺–S(Cys) and S–C_β(Cys) bonds as well as a change in conformation of the cysteinyl side chain, which was associated with the alteration of the NH hydrogen bonding involving the sulfur ligand. The effects of the isoleucine mutations on the reactivity of SOR with O₂ ^?? were investigated by pulse radiolysis. These studies showed that the mutations induced a specific increase of the pK _a of the first reaction intermediate, recently proposed to be an Fe²⁺–O₂ ^?? species. These data were supported by density functional theory calculations conducted on three models of the Fe²⁺–O₂ ^?? intermediate, with one, two, or no hydrogen bonds involving the sulfur ligand. Our results demonstrated that the hydrogen bonds between the NH (peptide) and the cysteine ligand tightly control the rate of protonation of the Fe²⁺–O₂ ^?? reaction intermediate to form an Fe³⁺–OOH species.     

Expression profile of the α subunit of the heterotrimeric G protein in rice

Previous studies on the activity of the rice Gα promoter using a β-Glucuronidase (GUS) reporter construct indicated that Gα expression was highest in developing organs and changed in a developmental stage-dependent manner. In this paper, GUS activity derived from the rice Gα promoter was analyzed in seeds and developing leaves. In seeds, GUS activity was detected in the aleurone layer, embryo, endosperm and scutellar epithelium. In developing leaves, the activity was detected in the mesophyll tissues, phloem and xylem of the leaf sheath and in the mesophyll tissue of the leaf blade. The activity in the aleurone layer and scutellar epithelium suggests that the Gα subunit may be involved in gibberellin signaling. The activity in the mesophyll tissues of the leaf blade suggests that the Gα subunit may be related to the intensity of disease resistance. The pattern of the activity in the developing leaf also indicates that the expression of Gα follows a developmental profile at the tissue level.Key words: expression pattern, Gα subunit, GUS staining pattern, heterotrimeric G protein, riceThe rice mutant d1 is deficient in the heterotrimeric G protein α subunit (Gα). Recently it was found that the dwarfism phenotype of d1 is due to a reduction in cell numbers.¹ This discovery has led to new questions regarding how rice Gα regulates cell number, and which other signaling molecules are involved in this process in various tissues and at different development stages. Studies of d1 suggest that rice Gα participates in both gibberellin signaling^2–4 and brassinosteroid signaling.^5–8 Promoter studies using the β-Glucuronidase (GUS) reporter indicate that Gα expression is highest in developing organs.¹ In this paper, we report on the expression pattern of a Gα promoter::GUS construct in seeds and developing leaves of rice.     

Evaluation of two commercial methods for the susceptibility testing of Candida species: Vitek 2® and Sensititre YeastOne®

Background

An increased incidence of fungal infections caused by Candida species, especially Candida glabrata and Candida krusei, which are less susceptible to azoles, has been observed. Standardized susceptibility testing is essential for clinical management and for monitoring the epidemiology of resistance.

Developmental programming of reproduction and fertility: what is the evidence?

The concept of the foetal/developmental origins of adult disease has been around for ~20 years and from the original epidemiological studies in human populations much more evidence has accumulated from the many studies in animal models. The majority of these have focused upon the role of early dietary intake before conception, through gestation and/or lactation and subsequent interactions with the postnatal environment, e.g. dietary and physical activity exposures. Whilst a number of theoretical models have been proposed to place the experimental data into a biological context, the underlying phenomena remain the same; developmental deficits (of single (micro) nutrients) during critical or sensitive periods of tissue growth alter the developmental pathway to ultimately constrain later functional capacity when the individual is adult. Ageing, without exception, exacerbates any programmed sequelae. Thus, adult phenotypes that have been relatively easy to characterise (e.g. blood pressure, insulin sensitivity, body fat mass) have received most attention in the literature. To date, relatively few studies have considered the effect of differential early environmental exposures on reproductive function and fecundity in predominantly mono-ovular species such as the sheep, cow and human. The available evidence suggests that prenatal insults, undernutrition for example, have little effect on lifetime reproductive capacity despite subtle effects on the hypothalamic-pituitary-gonadal axis and gonadal progenitor cell complement. The postnatal environment is clearly important, however, since neonatal/adolescent growth acceleration (itself not independent from prenatal experience) has been shown to significantly influence fecundity in farm animals. The present paper will expand these interesting areas of investigation and review the available evidence regarding developmental programming of reproduction and fertility. However, it appears there is little strong evidence to indicate that offspring fertility and reproductive senescence in the human and in farm animal species are overtly affected by prenatal nutrient exposure. Nevertheless, it is clear that the developing gonad is sensitive to its immediate environment but more detailed investigation is required to specifically test the long-term consequences of nutritional perturbations during pregnancy on adult reproductive well-being.     

Genome size and DNA base composition of geophytes: the mirror of phenology and ecology?

Background and Aims

Genome size is known to affect various plant traits such as stomatal size, seed mass, and flower or shoot phenology. However, these associations are not well understood for species with very large genomes, which are laregly represented by geophytic plants. No detailed associations are known between DNA base composition and genome size or species ecology.

Methods

Genome sizes and GC contents were measured in 219 geophytes together with tentative morpho-anatomical and ecological traits.

Key Results

Increased genome size was associated with earliness of flowering and tendency to grow in humid conditions, and there was a positive correlation between an increase in stomatal size in species with extremely large genomes. Seed mass of geophytes was closely related to their ecology, but not to genomic parameters. Genomic DNA GC content showed a unimodal relationship with genome size but no relationship with species ecology.

Conclusions

Evolution of genome size in geophytes is closely related to their ecology and phenology and is also associated with remarkable changes in DNA base composition. Although geophytism together with producing larger cells appears to be an advantageous strategy for fast development of an organism in seasonal habitats, the drought sensitivity of large stomata may restrict the occurrence of geophytes with very large genomes to regions not subject to water stress.     

Modulation of the orientational order profile of the lipid acyl chain in the Lα phase

The orientational order profile along the lipid acyl chain has been characterized under several different conditions of polar headgroup composition, temperature, and cholesterol content. Despite the different nature of these factors, the variation of the order is governed by two common trends. First, the relative change of order induced by the variation of these factors is always more pronounced towards the end of the chain than for the methylene groups near the interface. Second, there is, to a first approximation, a distinct correlation between the magnitude of the order parameters and the shape of the order profile. For example when the chain is highly ordered, the relative width of the order distribution is narrow indicating that the plateau region is longer. These conclusions suggest that the orientational order profile depends on only a small number of parameters and demonstrate clearly that the correlation length for changes in orientational order is much greater than one C-C bond length. Our results also show that the reduced temperature is not related in simple terms to orientational order and probably has little theoretical significance. The orientational order profiles of POPC and POPE bilayers are significantly different even when expressed in terms of reduced temperature. The behavior of POPC/cholesterol systems also indicates that the orientational order of the lipid chain and the gel-to-liquid crystalline phase transition temperature are not related in a straightforward manner.Abbreviations POPC 1-palmitoyl-2-oleoyl-phosphatidylcholine - POPE 1-palmitoyl-2-oleoyl-phosphatidylethanolamine - PC phosphatidylcholine - PE phosphatidylethanolamine - NMR nuclear magnetic resonance - EDTA ethylenediaminetetraacetic acid Offprint requests to: M. Bloom     

Usefulness of Chromogenic CromoCen® AGN agar medium for the identification of the genus Aeromonas: Assessment of faecal samples

Selective screening media for the detection and identification of Aeromonas strains are needed to guide primary isolation procedures in the clinical laboratory. This study compared the selective CromoCen? AGN chromogenic agar medium for the detection and identification of Aeromonas strains that were isolated from various samples against the conventional selective agar media that are commonly used for the isolation of this organism in food, environmental and clinical samples. The Miles and Misra and ecometric methods were used to evaluate the microbiological performance of CromoCen? AGN chromogenic agar medium, which was shown to be satisfactory. A total of 14 reference Aeromonas strains, 44 wild strains and 106 clinical stool specimens were examined using both non-chromogenic selective agars that are commonly used for Aeromonas isolation and CromoCen? AGN agar. The latter exhibited 94.73% sensitivity and 100% specificity for the various samples. On CromoCen? AGN agar medium, Aeromonas formed colonies with light green, greenish and salmon pigments with or without a surrounding wide transparent zone (halo) of 2-3mm in diameter around the entire border. This medium is recommended for the isolation and potential identification of the Aeromonas genus.     

Is meta-analysis the platinum standard of evidence?

An astonishing volume and diversity of evidence is available for many hypotheses in the biomedical and social sciences. Some of this evidence—usually from randomized controlled trials (RCTs)—is amalgamated by meta-analysis. Despite the ongoing debate regarding whether or not RCTs are the ‘gold-standard’ of evidence, it is usually meta-analysis which is considered the best source of evidence: meta-analysis is thought by many to be the platinum standard of evidence. However, I argue that meta-analysis falls far short of that standard. Different meta-analyses of the same evidence can reach contradictory conclusions. Meta-analysis fails to provide objective grounds for intersubjective assessments of hypotheses because numerous decisions must be made when performing a meta-analysis which allow wide latitude for subjective idiosyncrasies to influence its outcome. I end by suggesting that an older tradition of evidence in medicine—the plurality of reasoning strategies appealed to by the epidemiologist Sir Bradford Hill—is a superior strategy for assessing a large volume and diversity of evidence.     

Can humans discriminate between dogs on the base of the acoustic parameters of barks?

In this study we tested the often suggested claim that people are able to recognize their dogs by their barks. Earlier studies in other species indicated that reliable discrimination between individuals cannot be made by listening to chaotically noisy vocalizations. As barking is typically such a chaotic noisy vocalization, we have hypothesized that reliable discrimination between individuals is not possible by listening to barks. In this study, playback experiments were conducted to explore (1) how accurately humans discriminate between dogs by hearing only their barks, (2) the impact of the eliciting context of calls on these discrimination performances, and (3) how much such discrimination depends on acoustic parameters (tonality and frequency of barks, and the intervals between the individual barks). Our findings were consistent with the previous studies: human performances did not pass the empirical threshold of reliable discrimination in most cases. But a significant effect of tonality was found: discrimination between individuals was more successful when listeners were listening to low harmonic-to-noise ratio (HNR) barks. The contexts in which barks were recorded affected significantly the listeners' performances: if the dog barked at a stranger, listeners were able to discriminate the vocalizations better than if they were listening to sounds recorded when the dog was separated from its owner. It is rendered probable that the bark might be a more efficient communication system between humans and dogs for communicating the motivational state of an animal than for discrimination among strange individuals.