HIV, HEV and cirrhosis: evidence of a possible link from eastern Spain

OBJECTIVES

The aim of the study was to assess the seroprevalence of hepatitis E virus (HEV) infection in an HIV-infected population, as determined by HEV immunoglobulin G (IgG) antibodies (anti-HEV).

METHODS

The design of the study was cross-sectional. Serum anti-HEV IgG was determined by enzyme immunoassay in 238 HIV-infected patients consecutively attending our out-patient clinic between April and May 2011. In HEV-seropositive patients, HEV RNA was analysed by nested reverse transcriptase-polymerase chain reaction (RT-PCR). Associations between anti-HEV and liver cirrhosis, route of HIV infection, hepatitis B virus (HBV) and hepatitis C virus (HCV) serological markers, age, sex and alanine aminotransferase (ALT) levels were examined by univariate and multivariate analysis.

RESULTS

One hundred and forty patients (59%) had chronic liver disease (99% were HBV- and/or HCV-coinfected). Liver cirrhosis was detected in 44 individuals (19%). Two hundred and twelve patients (89%) were on antiretroviral treatment; the median CD4 T-cell count was 483 cells/μL [interquartile range (IQR) 313-662 cells/μL] and the HIV viral load was <25 HIV-1 RNA copies/mL. Overall, 22 patients (9%) were anti-HEV positive. Liver cirrhosis was the only factor independently associated with the presence of anti-HEV, which was documented in 23% of patients with cirrhosis and 6% of patients without cirrhosis (P=0.002; odds ratio 5.77). HEV RNA was detected in three seropositive patients (14%), two of whom had liver cirrhosis.

CONCLUSIONS

Our findings show a high prevalence of anti-HEV in HIV-infected patients, strongly associated with liver cirrhosis. Chronic HEV infection was detected in a significant number of HEV-seropositive patients. Further research is needed to ascertain whether cirrhosis is a predisposing factor for HEV infection and to assess the role of chronic HEV infection in the pathogeneses of cirrhosis in this population.

Identification and potency of cyclodextrin-lipid inhibitors of Staphylococcus aureus α-toxin

PURPOSE

Staphylococcus aureus, a leading cause of bacterial keratitis, secretes α-toxin, a cytotoxin active on the corneal epithelium. This study describes the production and testing of chemical inhibitors of α-toxin action.

METHODS

Purified α-toxin was titered by its ability to lyse rabbit erythrocytes in buffered saline (PBS). To prepare potential toxin inhibitors, each of 18 lipids was incorporated into a complex with methyl-β-cyclodextrin (MβCD) or hydroxypropyl-β-cyclodextrin (HPβCD). Serial dilutions of each lipid-cyclodextrin (CD-lipid) complex were mixed with α-toxin prior to the addition of rabbit erythrocytes. Select CD-lipid complexes were mixed with 12 hemolytic units (HU) α-toxin and injected into the rabbit corneal stroma so the resulting corneal erosions could be measured at 4 and 8 hours post-injection (PI). Eyes injected with toxin alone, MβCD, or HPβCD alone served as controls.

RESULTS

Neither form of CD alone inhibited α-toxin. Of the 36 complexes prepared, 6 lipid-CD complexes were found to inhibit >100 HU of α-toxin. Four lipid complexes able to inhibit >200 HU of α-toxin were tested in toxin-injected corneas; at 4 and 8 hours PI, the complexes of cholesterol or lanosterol with MβCD and squalene or desmosterol with HPβCD caused a significant reduction in the corneal erosion size as compared to eyes injected with α-toxin alone (P ≤ 0.05).

CONCLUSIONS

Specific lipid inclusion complexes with either MβCD or HPβCD demonstrated a significant inhibition of α-toxin in both in vitro and in vivo assays. Changes in either the cyclodextrin or lipid of a complex affected the inhibitory activity.

Surgery following neoadjuvant therapy in patients with HER2-positive locally advanced or inflammatory breast cancer participating in the NeOAdjuvant Herceptin (NOAH) study

AIM

To describe surgical outcomes in patients with HER2-positive locally advanced (LABC) or inflammatory breast cancer (IBC) participating in the NeOAdjuvant Herceptin (NOAH) study (ISRCTN86043495).

PATIENTS AND METHODS

A total of 235 patients with HER2-positive disease were randomized to neoadjuvant trastuzumab plus chemotherapy (doxorubicin plus paclitaxel, followed by paclitaxel, followed by cyclophosphamide, methotrexate and fluorouracil) or neoadjuvant chemotherapy alone. Of these patients, 228 received their allocated treatment (115 received trastuzumab plus chemotherapy and 113 received chemotherapy alone) and were potentially eligible for surgery. Mastectomy was required for all patients with IBC and was recommended for all patients with LABC. However, breast-conserving therapy could be considered for patients with peripheral neoplasms measuring ≤ 4 cm in diameter at diagnosis, with a favorable ratio of tumor to breast volume, or at the patient's request if there had been a good response to treatment.

RESULTS

As previously reported, the addition of trastuzumab to neoadjuvant chemotherapy improved the overall, complete and pathological complete response to therapy and significantly improved event-free survival (the primary endpoint of the study). Trastuzumab also enabled more patients to have breast conserving surgery (BCS) (23% versus 13% respectively) without an apparent detrimental effect on local disease control (no patient treated with trastuzumab plus chemotherapy had experienced a local recurrence after BCS at the time of analysis).

CONCLUSIONS

Although this was not an aim of the trial, neoadjuvant trastuzumab given concurrently with chemotherapy enabled 23% of patients with HER2-positive LABC/IBC to avoid mastectomy (including a small number of patients with IBC).

The relative contribution of band number to phylogenetic accuracy in AFLP data sets

We examined the effect of increasing the number of sampled amplified fragment length polymorphism (AFLP) bands to reconstruct an accurate and well-supported AFLP-based phylogeny. In silico AFLP was performed using simulated DNA sequences evolving along balanced and unbalanced model trees with recent, uniform and ancient radiations and average branch lengths (from the most internal node to the tip) ranging from 0.02 to 0.05 substitutions per site. Trees were estimated by minimum evolution (ME) and maximum parsimony (MP) methods from both DNA sequences and virtual AFLP fingerprints. The comparison of the true tree with the estimated AFLP trees suggests that moderate numbers of AFLP bands are necessary to recover the correct topology with high bootstrap support values (i.e. >70%). Fewer numbers of bands are necessary for shorter tree lengths and for balanced than for unbalanced tree topologies. However, branch length estimation was rather unreliable and did not improve substantially after a certain number of bands were sampled. These results hold for different levels of genome coverage and number of taxa analysed. In silico AFLP using bacterial genomic DNA sequences recovered a well-supported tree topology that mirrored an empirical phylogeny based on a set of 31 orthologous gene sequences when as few as 263 AFLP bands were scored. These results suggest that AFLPs may be an efficient alternative to traditional DNA sequencing for accurate topology reconstruction of shallow trees when not very short ancestral branches exist.

Distribution of the HLA class II frequency alleles in patients with leprosy from the mid-west of Brazil

In an attempt to clarify the issue of genetic predisposition to leprosy, we examined the distribution of class II human leucocyte antigen variants (DR and DQ) in 70 patients from around the city of Goiânia, Brazil. Only two of the patients presented the tuberculoid form of the disease, whereas 17 fell into the lepromatous category; 51 were intermediate. The allele frequencies found were compared with those in a group of 77 healthy controls. We found an increased frequency of the HLA-DRB1*11 allele in patients with lepromatous leprosy compared with healthy controls (P=0.0132; RR=4.130, 95% Cl: 1.338 to 12.747). These results suggest that the DRB1*11 allele could be related with susceptibility to lepromatous leprosy in Brazil.

Influence of design on bioactivity of novel CaSiO3-CaMg(SiO3)2 bioceramics: in vitro simulated body fluid test and thermodynamic simulation

A new type of bioactive ceramic has been designed and obtained from high-temperature phase information from the wollastonite (CaSiO(3))-diopside (CaMg(SiO(3))(2)) phase equilibrium diagram. The selected composition was that corresponding to the eutectic point of the pseudobinary CaSiO(3)-CaMg(SiO(3))(2) system. The sintering behaviour, phase evolution, microstructural changes and in vitro bioactivity of CaSiO(3)-CaMg(SiO(3))(2) eutectic bioceramics were analysed by differential thermal analysis, X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and image analysis. A simulation of the dissolution properties of the different materials studied, in water as well as in simulated body fluid (SBF), was also carried out by thermodynamic calculations, with the purpose of understanding the in vitro results obtained. The results demonstrate that the CaMg(SiO(3))(2) is significantly less soluble than CaSiO(3), developing an in situ porous structure (biomimetic porous bone material) with adequate biodegradation rate and stability strength when immersed in SBF. The influence of the microstructure (porosity, grain size and phase composition) on the in vitro bioactivity of the obtained bioceramics was also examined.

Evaluating the relationship between evolutionary divergence and phylogenetic accuracy in AFLP data sets

Using in silico amplified fragment length polymorphism (AFLP) fingerprints, we explore the relationship between sequence similarity and phylogeny accuracy to test when, in terms of genetic divergence, the quality of AFLP data becomes too low to be informative for a reliable phylogenetic reconstruction. We generated DNA sequences with known phylogenies using balanced and unbalanced trees with recent, uniform and ancient radiations, and average branch lengths (from the most internal node to the tip) ranging from 0.02 to 0.4 substitutions per site. The resulting sequences were used to emulate the AFLP procedure. Trees were estimated by maximum parsimony (MP), neighbor-joining (NJ), and minimum evolution (ME) methods from both DNA sequences and virtual AFLP fingerprints. The estimated trees were compared with the reference trees using a score that measures overall differences in both topology and relative branch length. As expected, the accuracy of AFLP-based phylogenies decreased dramatically in the more divergent data sets. Above a divergence of approximately 0.05, AFLP-based phylogenies were largely inaccurate irrespective of the distinct topology, radiation model, or phylogenetic method used. This value represents an upper bound of expected tree accuracy for data sets with a simple divergence history; AFLP data sets with a similar divergence but with unbalanced topologies and short ancestral branches produced much less accurate trees. The lack of homology of AFLP bands quickly increases with divergence and reaches its maximum value (100%) at a divergence of only 0.4. Low guanine-cytosine (GC) contents increase the number of nonhomologous bands in AFLP data sets and lead to less reliable trees. However, the effect of the lack of band homology on tree accuracy is surprisingly small relative to the negative impact due to the low information content of AFLP characters. Tree-building methods based on genetic distance displayed similar trends and outperformed parsimony at low but not at high divergences. However, the impact of using alternative phylogenetic methods on tree accuracy was generally small relative to the uncertainty arising from factors such as divergence, nonhomology of bands, or the low information content of AFLP characters. Nevertheless, our data suggest that under certain circumstances, AFLPs may be suitable to reconstruct deeper phylogenies than usually accepted.

The action of purifying selection, mutation and drift on fitness epistatic systems

For different fitness mutational models, with epistasis introduced, we simulated the consequences of drift (D scenario) or mutation, selection, and drift (MSD scenario) in populations at the MSD balance subsequently subjected to bottlenecks of size N = 2, 10, 50 during 100 generations. No "conversion" of nonadditive into additive variance was observed, all components of the fitness genetic variance initially increasing with the inbreeding coefficient F and subsequently decreasing to zero (D) or to an equilibrium value (MSD). In the D scenario, epistasis had no appreciable effect on inbreeding depression and that on the temporal change of variance components was relevant only for high rates of strong epistatic mutation. In parallel, between-line differentiation in mean fitness accelerated with F and that in additive variance reached a maximum at F approximately 0.6-0.7, both processes being intensified by strong epistasis. In the MSD scenario, however, the increase in additive variance was smaller, as it was used by selection to purge inbreeding depression (N > or = 10), and selection prevented between-line differentiation. Epistasis, either synergistic or antagonistic (this leading to multiple adaptive peaks), had no appreciable effect on MSD results nor, therefore, on the evolutionary rate of fitness change.

Relative role of genetic determination and plastic response during ontogeny for shell-shape traits subjected to diversifying selection

We studied the relative role of genetic determination versus plastic response for traits involved in ecological adaptation of two ecotypes of Littorina saxatilis living at different shore levels. To investigate the magnitude of the plastic response across ontogeny, we compared morphological data from individuals grown in the laboratory and taken from the wild at three developmental stages: shelled embryos, juveniles, and adults. The results indicate that most shell shape variation (72-99%) in adaptive traits (globosity and aperture of the shell) is explained by the ecotype irrespective of the growth environment, suggesting that direct genetic determination is the main factor responsible for the process of adaptation in the wild. There was a tendency for the contribution of plasticity to increase over ontogeny but, in general, the direction of the plastic response did not suggest that this was adaptive.

Preserving population allele frequencies in ex situ conservation programs

Optimization of contributions of parents to progeny by minimizing the average coancestry of the progeny is an effective strategy for maintaining genetic diversity in ex situ conservation programs, but its application on the basis of molecular markers has the negative collateral effect of homogenizing the allelic frequencies at each locus. Because one of the objectives of a conservation program is to preserve the genetic composition of the original endangered population, we devised a method in which markers are used to maintain the allele frequency distribution at each locus as closely as possible to that of the native population. Contributions of parents were obtained so as to minimize changes in allele frequency for a set of molecular markers in a population of reduced size. We used computer simulations, under a range of scenarios, to assess the effectiveness of the method in comparison with methods in which contributions of minimum coancestry are sought, either making use of molecular markers or genealogical information. Our simulations indicated that the proposed method effectively maintained the original distribution of allele frequencies, particularly under strong linkage, and maintained acceptable levels of genetic diversity in the population. Nevertheless, contributions of minimum coancestry determined from pedigree information but ignoring the genealogy previous to the conservation program, was the most effective method for maintaining allelic frequencies in realistic situations.