Branched GDGT-based temperature calibrations from Central European lakes

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are common in lake sediments, where they are frequently employed to infer mean annual air temperatures (MAAT) or air temperatures of months above freezing (MAF) using the MBT'5Me lipid paleothermometer. The reliable reconstruction of such temperatures, however, requires robust calibration functions. Here, we investigated brGDGT distributions in surface sediments from 41 freshwater lakes located along an altitudinal gradient across the Alps (Central Europe) and spanning a MAAT range from 1.3 to 12.9 °C. Linear regression analysis demonstrates that fractional abundances of brGDGTs are strongly correlated with MAAT and MAF allowing to establish regional MBT'5Me-based transfer functions: MAAT (°C) = -2.19 + 31.91 × MBT'5Me (r2 = 0.72; RMSE = 1.51 °C) and MAF (°C) = 4.81 + 15.64 × MBT'5Me (r2 = 0.64, RMSE = 0.92 °C). Stepwise forward selection yielded the following, alternate temperature calibrations: MAAT (°C) = 7.11 + 67.66 × Ib - 13.54 × IIIa (r2 = 0.72; RMSE = 1.47 °C) and MAF (°C) = 5.19 + 16.22 × Ia (r2 = 0.66; RMSE = 0.98 °C). Our results demonstrate that the above calibration functions allow precise temperature reconstructions using lacustrine sediment records. However, our data also show that high-altitude lakes are more prone to warm bias and that lakes characterized by comparatively high abundances of 6-methyl brGDGTs show aberrant behaviors with temperature offsets up to ∼7 °C. Determining the IR6Me, as an independent control complementary to the MBT'5Me, is thus essential to validate the robustness of brGDGT-based temperature reconstructions of past climates. A cut-off value of 0.50 for the IR6Me is here proposed, after which MBT'5Me-reconstructed MAATs from lacustrine archives should be regarded as unreliable.

Climate change-related growth improvements in a wide niche-breadth tree species across contrasting environments

BACKGROUND AND AIMS

The vulnerability and responsiveness of forests to drought are immensely variable across biomes. Intraspecific tree responses to drought in species with wide niche breadths that grow across contrasting climatically environments might provide key information regarding forest resistance and changes in species distribution under climate change. Using a species with an exceptionally wide niche breath, we tested the hypothesis that tree populations thriving in dry environments are more resistant to drought than those growing in moist locations.

METHODS

We determined temporal trends in tree radial growth of 12 tree populations of Nothofagus antarctica (Nothofagaceae) located across a sharp precipitation gradient (annual precipitation of 500-2000 mm) in Chile and Argentina. Using dendrochronological methods, we fitted generalized additive mixed-effect models to predict the annual basal area increment as a function of year and dryness (De Martonne aridity index). We also measured carbon and oxygen isotope signals (and estimated intrinsic water-use efficiency) to provide potential physiological causes for tree growth responses to drought.

KEY RESULTS

We found unexpected improvements in growth during 1980-1998 in moist sites, while growth responses in dry sites were mixed. All populations, independent of site moisture, showed an increase in their intrinsic water-use efficiency in recent decades, a tendency that seemed to be explained by an increase in the photosynthetic rate instead of drought-induced stomatal closure, given that δ18O did not change with time.

CONCLUSIONS

The absence of drought-induced negative effects on tree growth in a tree species with a wide niche breadth is promising because it might relate to the causal mechanisms tree species possess to face ongoing drought events. We suggest that the drought resistance of N. antarctica might be attributable to its low stature and relatively low growth rate.

Multi-isotope fingerprints of recent environmental samples from the Baltic coast and their implications for bioarchaeological studies

Stable isotopes in coastal regions are influenced by the so-called sea spray effect which masks the actual terrestrial isotope fingerprint with a marine isotope signal. The sea spray impact on plants was investigated by analyzing different stable isotope systems (δ¹³C_cellulose, δ¹⁸O_cellulose, δ¹⁸O_sulfate, δ³⁴S_sulfate, δ³⁴S_{total S}, δ³⁴S_{organic S}, ⁸⁷Sr/⁸⁶Sr) in recent environmental samples (plants, soil, water) collected close to the Baltic Sea. All these isotopic systems are influenced by the sea spray, either by the uptake of ions (HCO₃^-, SO₄^2-, Sr²⁺) of marine origin, thus exhibiting a marine isotopic signature, or by biochemical reactions associated with, e.g., salinity stress. A shift towards seawater values is observed for δ¹⁸O_sulfate, δ³⁴S, and ⁸⁷Sr/⁸⁶Sr. Cellulose becomes enriched in ¹³C and ¹⁸O due to sea spray, further enhanced (δ¹³C_cellulose) or mitigated (δ¹⁸O_cellulose) by salinity stress. The effect differs both regionally and seasonally, probably as a result of, e.g., differences in wind strength or prevailing wind direction, as well as between plants collected only few meters apart, in either the open field or at more wind-protected sites, reflecting samples more or less influenced by sea spray. The stable isotope data of recent environmental samples are compared to previously analyzed archaeological bone samples of animals from the Viking Haithabu and Early Medieval Schleswig sites located close to the Baltic Sea. Potential regions of origin can be predicted based on the magnitude of the (recent) local sea spray effect. This enables the identification of probably non-local individuals. The insights into sea spray mechanisms, biochemical reactions in plants, as well as seasonal, regional, and small-scale differences in stable isotope data will help to interpret multi-isotope fingerprints at coastal sites. Our study demonstrates the usefulness of environmental samples for bioarchaeological studies. Moreover, the detected seasonal and small-scale differences require adjusted sampling strategies for, e.g., isotopic baselines in coastal areas.

Identification and quantification of the sea spray effect on isotopic systems in α-cellulose (δ13C, δ18O), total sulfur (δ34S), and 87Sr/86Sr of European beach grass (Ammophila arenaria, L.) in a greenhouse experiment

The sea spray effect can severely influence the isotopic signature of terrestrial individuals in coastal regions. To further specify this effect, beach grass was grown in a greenhouse under controlled environmental conditions and sprayed with mineral salt solution containing different mineral salts but only traces of NaCl (group 1). Another group of plants was sprayed with salty water from the Schlei inlet and the Baltic Sea, respectively (group 2). Control plants were only sprayed with tap water. Isotope analyses were conducted on the unwashed and washed plants (δ¹³C_cellulose, δ¹⁸O_cellulose, δ³⁴S_{total S}, ⁸⁷Sr/⁸⁶Sr), soil (δ¹⁸O_sulfate, δ³⁴S_sulfate, ⁸⁷Sr/⁸⁶Sr), and spray as well as irrigation water (δ¹⁸O_sulfate, δ³⁴S_sulfate, ⁸⁷Sr/⁸⁶Sr). Moreover, elemental analyses were performed on the water samples. The sea spray effect was visible in all isotopic systems under study. The uptake of SO₄^2-, HCO₃^-, and Sr²⁺ directly affected plants of group 1, while plants of group 2, sprayed with salty water, additionally showed salinity stress in the case of α-cellulose and total sulfur due to biochemical reactions of the plants. Very high concentrations in HCO₃^- or SO₄^2- also affected the plants' isotopic signatures. The impact of the sea spray and additional stress reactions were quantified. Our study is the first experiment creating an artificial sea spray effect in a greenhouse. This experiment for the first time enables the identification and quantification of the sea spray effect in environmental samples. The marine signature taken up by the plants and recorded by the investigated isotopic systems is apparently high and should have an impact on the isotopic fingerprints of animal consumers at the coast, as evidenced for archaeological animals from the Viking Haithabu and the early medieval Schleswig sites located close to the Baltic Sea. This result demonstrates the potential of greenhouse experiments as an isotopic predictor of the past local sea spray effect.

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log₁₀ increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

Multidisciplinary dataset for geological and environmental studies in the lake of Cavazzo (Southern Alps)

The present dataset was collected to evaluate the environmental stressors on a lacustrine basin in the Eastern Alps of glacial origin that has been affected in recent years by natural and anthropogenic events such as the construction of a hydroelectric power plant and a series of strong earthquakes during 1976-1977. We collected sediment cores in different sites from the lake margins to the depocenter and performed a multiproxy analysis of sediment sample to highlight lake stratigraphy and major changes occurring at a decadal scale (Polonia et al., [1]). The integrated analyses of sedimentological, geochemical, isotopic, mineralogical and micropaleontological analyses aimed at reconstructing changes in sediment composition and define the triggering mechanisms of altered environmental conditions. The dataset demonstrates that evaluating ex post the effects of artificial modification in a natural environment during relatively long time spans (decades) can provide important insights for managing and protection strategies in similar environments worldwide.

Functional Hypogonadism and Testosterone Deficiency in Aging Males With and Without HIV-infection

INTRODUCTION

HIV infection has become a chronic, well-treatable disease and the focus of caretakers has shifted to diagnosis and treatment of comorbidities. Hypogonadism in elderly men with HIV might be of particular relevance, however, little is known about its epidemiology in contrast to non-infected peers and men with other chronic medical conditions, such as type 2 diabetes. This study aimed at comparing the prevalence of testosterone deficiency and functional hypogonadism in men ≥ 50 years in these three groups.

PATIENTS AND METHODS

Multi-center, cross-sectional substudy of the German-wide 50/2010 study, including men aged 50 years or older with HIV-infection, type 2 diabetes, and controls.

RESULTS

Altogether, 322 men were included (mean age: 62 years (SD±7.9)). The prevalence of testosterone deficiency in men living with HIV, type 2 diabetes, and controls was 34.5, 44.9, and 35.0%, respectively; the prevalence of functional hypogonadism was 7.7, 14.3 and 3.5%, respectively. Single-factor ANOVA demonstrated significant differences between the groups for total testosterone (p<0.001), SHBG (p<0.001), as well as for free testosterone concentrations (p=0.006). Comorbidities were, however, most important single factor in multi-factor analysis.

DISCUSSION

Despite a comparable prevalence of testosterone deficiency, functional hypogonadism was more frequent in men living with HIV when compared to non-infected controls. This was the result of a higher burden of symptoms that might, however, also be secondary to other conditions. Number of comorbidities was a more important factor than belonging to one of the groups.

Sea spray correction in δ13Ccarbonate, δ18Ocarbonate, δ18Ophosphate, and δ34Scollagen values of coastal humans - A methodological approach

The so-called sea spray effect influences animals and humans living in coastal regions. As a consequence, δ¹³C_carbonate, δ¹⁸O_carbonate, δ¹⁸O_phosphate, and δ³⁴S_collagen isotope values of affected individuals are more positive than otherwise expected. However, the effect is hidden in the case of humans who actually might have consumed marine food what would (partly) explain their isotopic signature. In order to correct for the sea spray effect in humans the dietary proportions were calculated based on the δ¹³C_collagen and δ¹⁵N_collagen isotope values using stable isotope mixing models. Four different programs (SISUS, simmr, IsotopeR, MixSIAR) were applied which resulted in quite different calculated diets. Each individual human can be corrected for the sea spray effect using the calculated proportion of terrestrial food (e.g. domesticated mammals, plants) and the approximated sea spray effect for each isotopic system. The differences in the calculated food proportions detected for the different mixing model programs, however, lead to differences in the correction procedure. We suggest using the dietary proportions as obtained by probabilistic SISUS rather than those of the Bayesian programs (simmr, IsotopeR, MixSIAR). The correction against the sea spray effect using the dietary proportions calculated by SISUS was supported by Gaussian Mixture Model (GMM) clustering which also enables the identification of probably non-local individuals in the dataset.

Stable isotope relationships between apatite phosphate (δ18 O), structural carbonate (δ18 O, δ13 C), and collagen (δ2 H, δ13 C, δ15 N, δ34 S) in modern human dentine

RATIONALE

The use of multi-isotopic analysis (δ² H, δ¹³ C, δ¹⁵ N, δ¹⁸ O, and δ³⁴ S values) of modern human body tissues for provenancing of unknown individuals in forensics is increasing. Tooth dentine develops during childhood and adolescence, therefore providing geographical information from that period of life. Tooth apatite δ¹⁸ O values are commonly used for the reconstruction of drinking water values, and H-C-N-S isotope ratios in collagen supply additional information about the composition of diet. We tested if dentine collagen δ² H values provide similar information to apatite δ¹⁸ O values with a proof-of-concept study.

METHODS

Tooth samples were taken from modern-day individuals born in different regions of the world. Apatite and collagen were prepared from dentine. Stable isotope analyses were performed on apatite phosphate oxygen (δ¹⁸ O_phos ); oxygen and carbon of the structural carbonate (δ¹⁸ O_carb , δ¹³ C_carb ); and hydrogen, carbon, nitrogen, and sulfur of the collagen (δ² H_coll, δ¹³ C_coll , δ¹⁵ N, δ³⁴ S).

RESULTS

δ¹⁸ O_phos , δ¹⁸ O_carb , and δ² H_coll values are highly correlated in modern human dentine. There are significant relationships of δ¹⁸ O values in the apatite fraction and δ² H values in the collagen fraction with local δ¹⁸ O and δ² H precipitation values, respectively. Pearson correlation coefficients indicate no direct relationship between δ¹⁵ N values and the isotope ratios of any other element. Weak relationships exist between collagen δ³⁴ S values and δ¹⁸ O_carb or δ¹⁸ O_phos values.

CONCLUSIONS

The highly significant correlation of δ¹⁸ O_phos , δ¹⁸ O_carb , and δ² H_coll values in the modern human dentine implies that measurement of δ² H values in collagen or δ¹⁸ O values in bioapatite will provide reliable information about the climate at the person's whereabouts.

Stable isotope records of sei whale baleens from Chilean Patagonia as archives for feeding and migration behavior

Carbon (δ13C) and nitrogen (δ15N) stable isotope variations in baleen plates of sei whales (Balaenoptera borealis) stranded after a mass mortality event in Chilean Patagonia were investigated to assess potential dietary and migratory patterns. Carbon and nitrogen isotope ratios of seven baleens from six individuals were analyzed. The δ13C values ranged from - 19.1 to - 15.9‰ and the δ15N values from 8.7 to 15.4‰. Variations of up to 2.9‰ for δ13C and 5.3‰ for δ15N were observed within one baleen. Carbon and nitrogen isotope records of each baleen were significantly correlated and showed recurring oscillations confirmed by wavelet analyses. Oscillations slightly differed in periodicity indicating variable baleen growth rates between 10.0 and 16.5 cm/year. Food sources of the whales are discussed in terms of available isotope data for potential prey taxa and potential migratory behavior on the basis of latitudinal isotope gradients of particulate organic matter. Cyclicity could be explained by regular migrations of the sei whales from subtropical calving areas to high-latitude foraging grounds. δ15N records of baleens differed between individuals eventually pointing to diverse feeding and migratory preferences among sei whale individuals.

Influence of Platelet Lysate on 2D and 3D Amniotic Mesenchymal Stem Cell Cultures

The mechanobiological behavior of mesenchymal stem cells (MSCs) in two- (2D) or three-dimensional (3D) cultures relies on the formation of actin filaments which occur as stress fibers and depends on mitochondrial dynamics involving vimentin intermediate filaments. Here we investigate whether human platelet lysate (HPL), that can potentially replace fetal bovine serum for clinical-scale expansion of functional cells, can modulate the stress fiber formation, alter mitochondrial morphology, change membrane elasticity and modulate immune regulatory molecules IDO and GARP in amnion derived MSCs. We can provide evidence that culture supplementation with HPL led to a reduction of stress fiber formation in 2D cultured MSCs compared to a conventional growth medium (MSCGM). 3D MSC cultures, in contrast, showed decreased actin concentrations independent of HPL supplementation. When stress fibers were further segregated by their binding to focal adhesions, a reduction in ventral stress fibers was observed in response to HPL in 2D cultured MSCs, while the length of the individual ventral stress fibers increased. Dorsal stress fibers or transverse arcs were not affected. Interestingly, ventral stress fiber formation did not correlate with membrane elasticity. 2D cultured MSCs did not show differences in the Young's modulus when propagated in the presence of HPL and further cultivation to passage 3 also had no effect on membrane elasticity. In addition, HPL reduced the mitochondrial mass of 2D cultured MSCs while the mitochondrial mass in 3D cultured MSCs was low initially. When mitochondria were segregated into punctuate, rods and networks, a cultivation-induced increase in punctuate and network mitochondria was observed in 2D cultured MSCs of passage 3. Finally, mRNA and protein expression of the immunomodulatory molecule IDO relied on stimulation of 2D culture MSCs with pro-inflammatory cytokines IFN-γ and TNF-α with no effect upon HPL supplementation. GARP mRNA and surface expression was constitutively expressed and did not respond to HPL supplementation or stimulation with IFN-γ and TNF-α. In conclusion, we can say that MSCs cultivated in 2D and 3D are sensitive to medium supplementation with HPL with changes in actin filament formation, mitochondrial dynamics and membrane elasticity that can have an impact on the immunomodulatory function of MSCs.

Evidence for sea spray effect on oxygen stable isotopes in bone phosphate - Approximation and correction using Gaussian Mixture Model clustering

Palaeobiodiversity research based on stable isotope analysis in coastal environments can be severely hampered by the so-called "sea spray" effect. This effect shifts the isotopic signal of terrestrial individuals towards too marine values. It is commonly agreed upon that sea spray influences sulphur stable isotopes. However, we were able to approximate a remarkable sea spray effect also in carbon and oxygen stable isotopes of bone carbonate previously. In the present study we could approximate a minimum sea spray effect of about 13.9% even present in oxygen isotope values of bone phosphate, which was validated by Gaussian Mixture Model (GMM) clustering. This approximated value is by some magnitudes smaller than the minimum sea spray effect approximated for both δ¹³C_carb and δ¹⁸O_carb, and quite close to the sea spray detected for δ³⁴S_coll in a previous study. It may therefore be interpreted as purer minimum sea spray signal compared to the approximation in bone carbonate. Furthermore, detection of sea spray in δ¹⁸O_phos can serve as additional validation of the effect present in bone carbonate, which is more prone to diagenetic alteration compared to bone phosphate. Moreover, the presence of the sea spray effect in both δ¹⁸O_carb and δ¹⁸O_phos demonstrates that sea spray can be taken up by terrestrial mammals not only via food (δ¹⁸O_carb) but also via drinking water (δ¹⁸O_phos). Finally, this study once more confirmed that calculation of δ¹⁸O_phos from δ¹⁸O_carb values using a fixed oxygen isotope spacing (Δδ¹⁸O) can be highly misleading, especially in coastal environments affected by sea spray.

Multi-isotope provenancing of archaeological skeletons including cremations in a reference area of the European Alps

RATIONALE

Due to the spatial heterogeneity of stable isotope ratios of single elements measured in attempts to georeference bioarchaeological finds, multi-isotope fingerprints are frequently employed under the assumption that similar isotopic signatures are indicative of similar shared environments by the individuals studied. The extraction of the spatial information from multi-isotope datasets, however, is challenging.

METHODS

Gaussian mixture clustering of six- to seven-dimensional isotopic fingerprints measured in archaeological animal and human bones was performed. Uncremated animal bones served for an isotopic mapping of a specific reference area of eminent archaeological importance, namely the Inn-Eisack-Adige passage across the European Alps. The fingerprints consist of ⁸⁷ Sr/⁸⁶ Sr, ²⁰⁸ Pb/²⁰⁴ Pb, ²⁰⁷ Pb/²⁰⁴ Pb, ²⁰⁶ Pb/²⁰⁴ Pb, ²⁰⁸ Pb/²⁰⁷ Pb, and ²⁰⁶ Pb/²⁰⁷ Pb ratios, and δ¹⁸ O_phosphate values in uncremated bone apatite, while the thermally unstable δ¹⁸ O values of human cremations from this region were discarded.

RESULTS

The bone finds were successfully decontaminated. Animal and human isotope clusters not only reflect individual similarities in the multi-isotopic fingerprints, but also permit a spatial allocation of the finds. This holds also for cremated finds where the δ¹⁸ O_phosphate value is no longer informative. To our knowledge, for the first time Pb stable isotopes have been systematically studied in cremated skeletal remains and proved significant in a region that was sought after for its ore deposits in prehistory.

CONCLUSIONS

Gaussian mixture clustering is a promising method for the interpretation of multi-isotopic fingerprints aiming at detecting and quantifying migration and trade.

Anxiety, depression, and health-related quality of life in aging people living with HIV compared to diabetes patients and patients with minor health conditions: a longitudinal study

HIV infection has evolved from a fatal to a treatable condition, leading to an increase in the rate of elderly People Living with HIV (PLWH). However, little is known about the psychosocial burden of elderly PLWH. Thus, the aim of this longitudinal multi-center cohort study was to investigate whether elderly PLWH experience more anxiety and depression and reduced health related quality of life (HRQOL) compared to elderly patients with other chronic conditions. PLWH were compared to diabetes patients (DM) and patients with minor health conditions (MHC), e.g. patients with hypertension or allergic conditions. All patients were over 50 years old. Anxiety and depression (HADS) as well as HRQOL (SF-36) were assessed at baseline and after 12 months. 218 PLWH, 249 DM and 254 MHC were included. At baseline, the study groups did not differ in anxiety, depression, and physical HRQOL. However, PLWH indicated lower mental HRQOL than DM and MHC patients (p = 0.001). We did not obtain any moderating effects showing a differential effect of patient characteristics on anxiety, depression, and HRQOL in the three patient groups. At follow-up, the level of anxiety, depression, and HRQOL did not change significantly. The prevalence of anxiety ranged between 27 and 35%, and that of depression between 17 and 28%. Thus, the results of our investigation tentatively suggest that the psychosocial adaptation to HIV among elderly PLWH resembles those of other chronic diseases. There may be some subtle impairments, though, as PLWH experienced lower mental HRQOL.

Persisting hepatitis E virus infection leading to liver cirrhosis despite recovery of the immune system in an HIV-infected patient

Chronic hepatitis E has been described several times in strongly immunosuppressed HIV-patients. We describe the persistence of HEV-infection in an HIV-patient despite a restored immune response. This case demonstrates that HEV-infection can persist in formerly immunosuppressed individuals irrespective of the current immune status. Persisting HEV-infection can lead to chronic inflammation and liver cirrhosis. Physicians should be aware of the possibility of chronic hepatitis E even in patients that are not any longer immunocompromised. However, ribavirin is an efficient treatment option.

Cost of HIV and determinants of health care costs in HIV-positive patients in Germany: results of the DAGNÄ K3A Study

OBJECTIVES

The aims of this study were to estimate the expenditure for HIV-care in Germany and to identify variables associated with resource use.

DESIGN/SETTING

We performed an 18-month prospective multi-center study in an HIV specialized ambulatory care setting from 2006 to 2009.

SUBJECTS, PARTICIPANTS

Patients were eligible for study participation if they (1) were HIV-positive, (2) were ≥ 18 years of age, (3) provided written consent and (4) were not enrolled in another clinical study; 518 patients from 17 centers were included.

MAIN OUTCOME MEASURES

Health care costs were estimated following a micro-costing approach from two perspectives: (1) costs incurred to society in general, and (2) costs incurred to statutory health insurance. Data were obtained using questionnaires. Several empirical models for identifying the relationship between health care costs and independent variables, including age, gender, route of transmission and CD4 cell count at baseline, were developed.

RESULTS

Average annual health care costs were <euro>23,298 per patient from the societal perspective and <euro>19,103 from the statutory health insurance perspective. Most expenses are caused by antiretroviral medication (80 % of the total and 89 % of direct costs), while hospital costs represented 7 % of total expenditure. A statistically significant association was found between health care costs and clinical variables, with higher CD4 count and female gender generating lower costs, while increased antiretroviral experience and injection drug use led to higher expenditures (P < 0.05).

CONCLUSIONS

Expenditures for HIV-infection are driven mainly by drug costs. We identified several clinical variables influencing the costs of HIV-treatment. This information could assist policymakers when allocating limited health care resources to HIV care.

Effects of organic matter on carbonate stable isotope ratios (δ13C, δ18O values)--implications for analyses of bulk sediments

RATIONALE

Stable isotope ratio (δ(13)C, δ(18)O values) analyses of carbonates can be biased by CO(2) release from organic impurities. This is most critical for carbonate isotope analyses from bulk sediments containing comparably high amounts of organic matter (OM). Several methods have been developed to remove OM prior to analyses, but none of them can be universally applied. Moreover, pretreatment methods cause isotopic bias in themselves and should probably best be avoided. Thus, it is essential to have indicators for reliable isotope values of untreated carbonate-OM mixtures.

METHODS

Artificial mixtures of organic compounds with a standard carbonate were analyzed to investigate the bias on carbonate isotope ratios caused by OM in the sample. The total-inorganic-carbon to total-organic-carbon ratio (TIC/TOC) was used as a measure for the " organic impurity" of the sample. The target was to evaluate TIC/TOC as a measure for sample quality and to define TIC/TOC thresholds for reliable isotope measurements of mixtures between calcium carbonate and organic compounds.

RESULTS

The effect of organic impurities on carbonate stable isotope values depended on the specific OM compound and the respective TIC/TOC ratio. Different CO(2) release rates were determined for the pure OM compounds. A sample TIC/TOC ratio ≥0.3 was found to be a threshold for reliable measurements of the isotope composition of calcium carbonate.

CONCLUSIONS

Bulk carbonate analyses from carbonate-OM mixtures are reliable only if the TIC/TOC values do not fall below certain thresholds. This has implications for carbonate isotope studies from bulk sediments for which the TIC/TOC ratios should be considered as an easy-to-determine measure for sample-quality assessment.

Nitrogen and carbon isotope variability in the green-algal lichen Xanthoria parietina and their implications on mycobiont-photobiont interactions

Stable isotope patterns in lichens are known to vary largely, but effects of substrate on carbon and nitrogen stable isotope signatures of lichens were previously not investigated systematically. N and C contents and stable isotope (δ(15)N, δ(13)C) patterns have been measured in 92 lichen specimens of Xanthoria parietina from southern Bavaria growing on different substrates (bark and stone). Photobiont and mycobiont were isolated from selected populations and isotopically analyzed. Molecular investigations of the internal transcribed spacer of the nuclear ribosomal DNA (ITS nrDNA) region have been conducted on a subset of the specimens of X. parietina. Phylogenetic analysis showed no correlation between the symbionts X. parietina and Trebouxia decolorans and the substrate, isotope composition, or geographic origin. Instead specimens grown on organic substrate significantly differ in isotope values from those on minerogenic substrate. This study documents that the lichens growing on bark use additional or different N sources than the lichens growing on stone. δ(15)N variation of X. parietina apparently is controlled predominantly by the mass fraction of the mycobiont and its nitrogen isotope composition. In contrast with mycobionts, photobionts of X. parietina are much more (15)N-depleted and show less isotopic variability than mycobionts, probably indicating a mycobiont-independent nitrogen acquisition by uptake of atmospheric ammonia.

Acute hepatitis C in persons infected with the human immunodeficiency virus (HIV): the "real-life setting" proves the concept

Objectives

Outbreaks of sexually transmitted acute HCV infection have been described recently in several cities in the western world. The epidemic affects mainly MSM who are coinfected with HIV and is supposably linked to certain sexual risk practices. Here, we compared our findings with current knowledge and recommendations.

Methods

HIV-positive patients with the diagnosis of acute HCV infection were included in the retrospective analysis. The patients came from outpatient infectious disease centers in northern German cities. We looked at markers of HIV and HCV infection and compared patients who received treatment and those who did not. Treated patients were followed up to 72 weeks.

Results

Three hundred nineteen HIV-positive patients with the diagnosis of acute hepatitis C between 2001 and 2008 and were included in the analysis. All patients were male, 315 (99%) patients were of caucasian origin, 296 (93%) declared homosexual contacts as a risk factor for HCV infection, intravenous drug use was declared in 3 (1%) cases. Median age at HCV diagnosis was 40 years (range 20-69 years). Median HCV viral load was 1.2 × 10⁶ IU/mL, 222 patients (70%) had HCV genotype 1, 59 (18%) genotype 4. The median time of HIV infection was 5.5 years (range 0 to 22.4 years). Median HIV viral load was 110 copies/mL (range 25 to 10 × 10⁶ copies/mL). The median CD 4 count was 461 cells/mm³ (range 55- 1331 cells/mm³). Two hundred and fourty-six patients (77%) received anti-HCV treatment, and 175 (55%) had completed therapy by the time of the analysis. Median treatment duration was 33 weeks (IQR 24.1-49.9). 93 of the 175 treated patients (53%) reached a sustained virological response (SVR). In the multivariate analysis, ART at diagnosis, HCV RNA drop at week 12, hemoglobin levels and higher platelets were associated with SVR. Treatment duration was significantly higher in the SVR group (40.6 weeks vs 26.6 weeks, p < 0.0001). Seventy-three patients (23%) did not receive anti-HCV treatment. In 19 of the untreated patients (26%) the hepatitis C virus was cleared spontaneously.

Conclusions

Our findings confirm that acute hepatitis C in HIV infected patients affects mainly MSM who acquire HCV sexually. Patients had a short duration of HIV infection and a stable immunological situation. In this real-life setting from urban regions in northern Germany, treatment rates appear to be high and effective.

The rainbow cohort: 96 week follow-up of saquinavir-containing regimens in previously antiretroviral therapy (ART)-naive and pre-treated but protease inhibitor (PI)-naive HIV-infected patients

Objective

We have previously reported data from the German cohort of the multinational observational prospective RAINBOW survey which assessed the tolerability and efficacy of ritonavir-boosted saquinavir (SQV/r)-containing regimens over 48 weeks in routine clinical practice. This analysis presents data from antiretroviral (ART)-naïve and pretreated but protease inhibitor (PI)-naïve patients treated in a long-term one line (96 weeks) follow-up of the initial study.

Methods

All ART-and PI-naïve patients from the initial RAINBOW cohort who had recorded data to one line 96 weeks of treatment were eligible for inclusion in the current analysis. Efficacy assessments included the proportion of patients with HIV-1 RNA < 50 and < 400 copies/mL and changes in CD4 cell count from baseline to week 96. Tolerability assessments included changes in liver enzymes and lipid levels from baseline to week 96. For evaluation of efficacy, intent-to-treat analysis, in which missing values were recorded as failure (ITT), and last-observation-carried-forward (LOCF) analysis were used. Metabolic parameters were assessed using LOCF analysis.

Results

The analysis included 175 ART-naïve and 109 pretreated but PI-naïve patients. After 96 weeks, a similar proportion of patients in the ART-naïve and in the pretreated but Pi-naïve group had HIV-1 RNA levels < 400 copies/mL (68.0% and 70.6% [ITT], respectively; 96.6% and 90.8% [LOCF], respectively). The proportion of patients with HIV RNA < 50 copies/mL was higher in the ART-naïve group compared with the pretreated but PI-naïve group (61.1% and 56.9% [ITT], respectively; 84.0% and 75.2% [LOCF], respectively). Median change in CD4 cell count from baseline to week 96 was'+263 cells/mm³ (IQR 170; 384. LOCF; p < 0.0001) in the ART-naïve group, and one line +181 cells/mm³ (IQR 60; 309. LOCF; p < 0.0001) in the pretreated but PI-naïve group. Treatment was well tolerated, with only 2.5% of patients withdrawing from treatment due to side effects. There were no clinically relevant changes in liver enzyme levels. Overall total cholesterol, triglyceride, and low-and high-density lipoprotein levels increased to week 96, although levels remained within normal ranges in the majority of ART-naïve and pretreated patients.

Conclusions

This follow-up analysis confirms the long term efficacy and tolerability of SQV/r in ART-naïve and pretreated but PI-naïve patients in the real-life clinical setting.

Genetic variation in IL28B and treatment-induced clearance of hepatitis C virus in HIV-positive patients with acute and chronic hepatitis C

Recently, a IL28B (rs 12979860) gene polymorphism was identified as a predictor for response to hepatitis C virus-specific treatment in human immunodeficiency virus (HIV)-uninfected and -infected patients with chronic hepatitis C. In an analysis of HIV-infected patients with acute hepatitis C, we found that the IL28B genotype was associated with serum levels of hepatitis C virus RNA, g-GT, and CD4 cell count. In contrast to HIV-infected patients with chronic hepatitis C, the IL28B genotype was not significantly associated with treatment response rates in patients with acute hepatitis C. Thus, effects of the IL28B single-nucleotide polymorphism may differ in HIV-infected patients with chronic and acute hepatitis C.

Safety and efficacy after switch to a saquinavir-containing antiretroviral regimen in protease inhibitor pretreated HIV-positive patients

Objective

The RAINBOW survey is a multinational observational study assessing the tolerability and efficacy of ritonavir-boosted saquinavir (SQV/r), using the 500 mg film-coated SQV formulation, in routine clinical practice. This analysis presents data from the German subgroup of protease inhibitor (PI)-pretreated, but SQV-naïve patients.

Methods

Multicenter, prospective, open-label, 48 week cohort study. Efficacy assessments included the proportion of patients with HIV-1 RNA < 50 and < 400 copies/mL and changes in CD4 cell count from baseline to week 48. Tolerability assessments included changes in liver enzymes and lipid levels from baseline to week 48.

Results

A total of 426 patients were included in the analysis. The proportion of patients with HIV RNA levels < 50 copies/mL at week 48 was 60.3% (compared with 31.7% at switch to SQV/r) (intent-to-treat, last observation carried forward analysis). After 48 weeks, median CD4 count increased by +61 cells/mm³ from baseline (p < 0.01) and 60.3% of patients achieved HIV-1 RNA < 50 copies/mL. Median changes in fasting triglyceride levels (stratified according to baseline level) at week 48 were: +14 mg/dL (IQR -8; 57) for patients with baseline triglyceride < 200 mg/dL; -50 mg/dL (IQR -139; 0) for baseline triglyceride 200-750 mg/dL, and -656 mg/dL (IQR 1024; 0) for baseline triglyceride > 750 mg/dL (p < 0.01 for all). Median changes in fasting total cholesterol (TC) levels (stratified according to baseline) were +16 mg/dL (IQR -3; 43) for patients with baseline TC < 200 mg/dL (p < 0.01), -3 mg/dL (IQR -25; 25) for baseline TC 200-300 mg/dL (p = 0.4), and -47 mg/dL (IQR -87; -4) for baseline TC > 300 mg/dL (p < 0.01). No significant changes in liver enzymes or bilirubin were observed. SQV treatment was discontinued in 22% of patients, 6% due to side effects.

Conclusions

These data confirm the efficacy and tolerability of SQV/r in PI-experienced, SQV-naïve patients treated in a real-life clinical setting. Of particular relevance are the improvements in triglycerides and TC levels observed in patients with baseline grade III-IV elevations.

The influence of HAART on the efficacy and safety of pegylated interferon and ribavirin therapy for the treatment of chronic HCV infection in HIV-positive Individuals

Objective

This study was performed to investigate the impact of HAART versus no HAART and nucleoside free versus nucleoside containing HAART on the efficacy and safety of pegylated interferon and ribavirin therapy for the treatment of chronic HCV infection in HIV/HCV co-infected patients. In addition a control group of HCV mono-infected patients undergoing anti-HCV therapy was evaluated.

Methods

Multicenter, partially randomized, controlled clinical trial. HIV-negative and -positive patients with chronic HCV infection were treated with pegylated interferon alfa-2a and ribavirin (800 - 1200 mg/day) for 24 - 48 weeks in one of four treatment arms: HIV-negative (A), HIV-positive without HAART (B) and HIV-positive on HAART (C). Patients within arm C were randomized to receive open label either a nucleoside containing (C1) or a nucleoside free HAART (C2).

Results

168 patients were available for analysis. By intent-to-treat analysis similar sustained virological response rates (SVR, negative HCV-RNA 24 weeks after the end of therapy) were observed comparing HIV-negative and -positive patients (54% vs. 54%, p = 1.000). Among HIV-positive patients SVR rates were similar between patients off and on HAART (57% vs. 52%, p = 0.708). Higher SVR rates were observed in patients on a nucleoside free HAART compared to patients on a nucleoside containing HAART, though confounding could not be ruled out and in the intent-to-treat analysis the difference was not statistically significant (64% vs. 46%, p = 0.209).

Conclusions

Similar response rates for HCV therapy can be achieved in HIV-positive and -negative patients. Patients on nucleoside free HAART reached at least equal rates of sustained virological response compared to patients on standard HAART.

Safety and efficacy of a saquinavir-containing antiretroviral regimen in previously ART-naïve or pretreated but protease inhibitor-naïve HIV-positive patients

BACKGROUND

The RAINBOW survey is a multinational observational study assessing the tolerability and efficacy of ritonavir-boosted saquinavir (SQV/r), using the 500-mg film-coated SQV formulation, in routine clinical practice. This analysis presents data from the German subgroup of antiretroviral therapy (ART)-naïve and pretreated but protease inhibitor (PI)-naïve patients.

METHODS

This was a multicenter, prospective, open-label, 48-week observational cohort study. Tolerability assessments included changes in liver enzymes and lipid levels from baseline to week 48. Efficacy assessments included changes in the proportion of patients with HIV-1 RNA <50 and <400 copies/ml, and changes in CD4 cell count from baseline to week 48.

RESULTS

The analysis included 275 ART-naïve and 179 pretreated but PI-naïve patients. The proportion of ART-naïve patients achieving <50 copies/ml by 48 weeks was 53.1% by intent-to-treat (ITT) analysis and 67.3% using last observation carried forward (LOCF) analysis. In pretreated but PI-naïve patients, the proportions achieving <50 copies/ml by 48 weeks were 53.1% (ITT) and 70.4% (LOCF). The median increase in CD4 count at week 48 was +174 cells/mm3 (interquartile range [IQR] 86, 265) in the ART-naïve group and +100 cells/mm3 (IQR 0, 209) in the pretreated but PI-naïve group (p < 0.01 for both; LOCF). Drug-related adverse events were reported in 7.6% of ART-naïve and 2.8% of pretreated but PI-naïve patients. Treatment with SQV/r was stopped in 21.5% of ART-naïve and 17.9% of pretreated but PI-naïve patients (due to side effects in 3.3% and 2.8%, respectively). There were no clinically relevant changes in liver enzyme levels. Overall, the total cholesterol, triglyceride, low-density lipoprotein, and high-density lipoprotein levels increased to week 48, although the levels remained within normal ranges in the majority of patients.

CONCLUSIONS

The results of this observational cohort study of treatment with the 500-mg tablet formulation of SQV are consistent with high efficacy and tolerability results seen in controlled studies of SQV/r. This analysis confirms that SQV/r is effective and well tolerated in ART-naïve and pretreated but PI-naïve patients in 'real-world' clinical settings.

The Potential of Gene Transfer into Primary B-CLL Cells Using Recombinant Virus Vectors

Despite recent advances, chronic lymphocytic leukemia (CLL) as the most common leukemia remains a largely incurable disease. Modern treatment options include novel drugs like purine analogues, monoclonal antibodies and transplantation strategies. Moreover, gene transfer of immunostimulatory molecules is another, but still experimental approach that can be used to potentiate immune responses against leukemic cells. CD40 ligand (CD40L) was shown to be a promising molecule for immunotherapy of B-CLL playing a critical role in immune activation. However, CLL B cells are resistant to transduction with most currently available vector systems. Improving the efficiency and specificity of gene vectors is critical for the success of gene therapy in this area. Using replication defective adenovirus encoding CD40L (Ad-CD40L), immunologic and clinical responses were seen in CLL patients after infusion of autologous Ad-CD40L-CLL cells in a recent phase I trial. Due to the immunogenic nature of adenovirus vectors, alternative vector systems are currently explored. Recombinant adeno-associated virus (rAAV) was shown to enable efficient transduction of primary B-CLL cells. By use of a library of AAV clones with randomly modified capsids, receptor-targeting mutants with a tropism for CLL cells can be selected. Furthermore, helper-virus free Epstein-Barr virus (EBV)-based gene transfer vectors hold promise for development of CLL-targeted vaccines after remaining safety issues will be resolved. Herpes simplex virus (HSV)-based vectors, especially HSV amplicons, have favorable features for B-CLL gene transfer including high transduction efficiency, ability to infect postmitotic cells and a large packaging capacity. The challenge for the future will be to transfer these alternative vector systems into clinic and allow the detection of a CLL-specific immune response by use of defined tumor antigens. This will make it possible to establish the potential clinical role of gene therapy for CLL patients.

Effect of the interleukin-6 C174G gene polymorphism on treatment of acute and chronic hepatitis C in human immunodeficiency virus coinfected patients

Hepatitis C virus (HCV)/human immunodeficiency virus (HIV) coinfection poses a difficult therapeutic problem. Response to HCV-specific therapy is variable but might be influenced by host genetic factors, including polymorphisms of cytokine genes. Here, we studied whether interleukin-6 (IL-6) C174G gene polymorphism affects the response to antiviral treatment in HCV-infected HIV-positive subjects. We determined IL-6 genotypes in HIV-positive patients with acute (n = 52) and chronic (n = 60) hepatitis C treated with pegylated interferon-alpha. Two hundred ten HCV monoinfected, 197 HIV monoinfected, and 100 healthy individuals were studied as controls. Patients were classified into high and low producers according to IL-6 genotypes. Rates of sustained virological responses (SVRs) were compared between the IL-6 genotypes. Signal transducer and activator of transcription three phosphorylation was analyzed by Western blot in HCV core-transfected human hepatoma cell line (HUH7) cells. Distribution of IL-6 genotypes did not differ significantly between the study groups. SVR was achieved in 63% of HIV/HCV coinfected patients. Carriers of the IL-6 high producer (HP) genotype had significantly higher SVR rates than patients with an IL-6 low producer genotype (70.1% versus 52%; P < 0.002). This effect was seen in both HIV-positive patients with acute (74% versus 33%; P < 0.05) and chronic (66% versus 33%; P < 0.05) hepatitis C. Multivariate analysis confirmed IL-6 HP carriage as an independent positive predictor for SVR (Odd's ratio 6.1; P = 0.004). This effect corresponds to the in vitro observation that in HCV core-transfected HUH7 cells, IL-6 overcomes the HCV core-mediated inhibition of STAT3 activation.

CONCLUSION

Response rates to HCV-specific treatment are higher in HCV/HIV-positive patients carrying the IL-6 HP genotype, which might be because of IL-6 mediated STAT3 activation.

Gabor-like image filtering using a neural microcircuit

In this letter, we present an implementation of a neural microcircuit for image processing employing Hebbian-adaptive learning. The neuronal circuit utilizes only excitatory synapses to correlate action potentials, extracting the uncorrelated ones, which contain significant image information. This circuit is capable of approximating Gabor-like image filtering and other image processing functions.

Frameless stereotactic cannulation of the foramen ovale for ablative treatment of trigeminal neuralgia

OBJECTIVE

Ablative neurosurgical treatment of trigeminal neuralgia, including percutaneous radiofrequency thermocoagulation, requires cannulation of the foramen ovale. To maximize patient security and cannulation success, a frameless stereotactic system was evaluated in a phantom study, a cadaveric study, and a preliminary clinical trial.

METHODS

Frameless stereotaxy using an optical navigation system, an aiming device, and a noninvasive vacuum mouthpiece-based registration and patient fixation technique was used for the targeting of a test body based on 1-, 3-, and 5-mm axial computed tomographic slices and of the foramen ovale in three cadavers and 15 patients based on 3-mm axial computed tomographic slices.

RESULTS

The mean normal (x/y) localization accuracy/standard deviation (n = 360) was 1.31/0.67 mm (1-mm slices), 1.38/0.65 mm (3-mm slices), and 1.84/0.96 mm (5-mm slices). Significantly better results were achieved with 1- and 3-mm slices when compared with 5-mm slices (P < 0.001). The foramen ovale (3 x 6 mm) was successfully cannulated at the first attempt in all cadavers and patients, which indicates clinical localization accuracies better than 1.5 mm in the anteroposterior and 3 mm in the medial-lateral directions.

CONCLUSION

Based on the noninvasive Vogele-Bale-Hohner vacuum mouthpiece, there is no need for invasive head clamp fixation. Imaging, real laboratory simulation, and the actual surgical intervention can be separated in time and location. The presented data suggest that frameless stereotaxy is a predictable and reproducible procedure, which may enhance patient security and cannulation success independent of the surgeon's experience.

Consensus recommendation from a group of German experts for the use of enfuvirtide in heavily pretreated HIV patients

BACKGROUND

The EU approval of enfuvirtide (Fuzeon) was granted in May 2003 on the basis of the 48-week data from the TORO 1 and TORO 2 studies. Enfuvirtide is licensed for use in pretreated HIV patients experienced with three classes of drugs who exhibited treatment failure or who have shown intolerance to previous antiretroviral treatment regimens. Recent studies with the new protease inhibitors tipranavir and darunavir (RESIST and POWER studies) showed that a high proportion of heavily pretreated HIV patients achieve a viral load reduction to below the limit of detection when treated with enfuvirtide plus one of these new ritonavir-boosted protease inhibitors and an optimised background treatment regimen. The International AIDS Society (IAS-USA Panel) has recently updated its treatment guidelines in view of these new data and recommends the use of an antiretroviral treatment regimen containing at least two active drugs, one of which that has a new mechanism of action, for HIV patients who have been heavily pretreated. A new treatment goal has also emerged for heavily pretreated patients with advanced HIV disease: reduction of the viral load to below the detection limit of 50 copies/ml. The IAS concluded that the likelihood of achieving this treatment goal is higher when enfuvirtide is selected as one of the two active drugs.

OBJECTIVE

A panel of German experts convened to discuss the currently available data and to incorporate them into the updated German consensus recommendations for the use of enfuvirtide when switching treatment in heavily pretreated HIV patients.

METHODS

The consensus recommendations are based on published data from controlled, randomised clinical studies and on the expert opinions of the discussants.

RESULTS AND CONCLUSIONS

The consensus recommendations were developed to provide practice-relevant standardised recommendations for selecting suitable candidates for enfuvirtide therapy and for their management. Aspects including predictive prognostic factors, disease stage, selection of the optimised background regimen, early indicators of a response to enfuvirtide, as well as accompanying educational measures treatment were considered. New protease inhibitors or other remaining active drugs should be used together with enfuvirtide in heavily pretreated patients in order to enable at least two active drugs to be included in such a salvage regimen.

Current status of immunotherapy in B cell malignancies

Conventional treatment of hematologic malignancies mainly consists of chemotherapeutic agents or a combination of both, chemotherapy and monoclonal antibodies. Despite recent advances, chemotherapeutic treatments often remain unsatisfying due to severe side effects and incomplete long-term remission. Therefore the evaluation of novel therapeutic options is of great interest. B cell malignancies, in particularly follicular lymphomas, chronic lymphocytic leukemia and multiple myeloma, represent the most immune-responsive types of all human cancer. Several immunotherapeutic strategies are presently employed to combat these B-cell malignancies. Active immunotherapies include vaccination strategies with dendritic cells (DCs) and genetically-modified tumor cell preparations as well as DNA and protein vaccination. Most of these vaccines target the tumor-specific immunoglobulin idiotype and have already demonstrated some anti-lymphoma activity in early phase clinical trials while their definitive impact is evaluated in ongoing phase III randomized trials. In contrast to these active immunizations, T cells transduced with chimeric antigen receptors and donor leukocyte infusions (DLI) represent adoptive (passive) immunotherapies. Recent advances of gene transduction technologies enabled improvement of immunotherapeutic strategies based on genetic modification of malignant cells or adoptive T cells. Current early phase clinical trials are investigating the potential of these innovative approaches. At the moment it remains unclear if the novel immunotherapeutic strategies will be able to play a similar role in the treatment of B cell malignancies than the already established antibody-based immunotherapy.

Pegylated Interferon-α for the Treatment of Sexually Transmitted Acute Hepatitis C in HIV-Infected Individuals

Background

Sexually transmitted acute hepatitis C among HIV-positive homosexual men has been noted as an emerging epidemic.

Methods

Forty-seven patients with mainly sexually acquired, acute hepatitis C were enrolled in this prospective, multicentre trial, and 36 of these patients were treated within the acute phase of hepatitis C infection with pegylated interferon (peg-IFN) therapy.

Results

Early treatment resulted in sustained virological response in 61% of patients. Peg-IFN alone showed similar treatment response rates and lower incidence of anaemia compared with peg-IFN+ribavirin combination therapy. Higher treatment response rates were observed in patients treated over 48 weeks compared with 24 weeks.

Conclusions

Treatment of hepatitis C in HIV-positive individuals in the acute phase of infection leads to high rates of sustained virological response. Optimal time and mode of therapy have yet to be defined.

Pegylated interferon-alpha for the treatment of sexually transmitted acute hepatitis C in HIV-infected individuals

BACKGROUND

Sexually transmitted acute hepatitis C among HIV-positive homosexual men has been noted as an emerging epidemic.

METHODS

Forty-seven patients with mainly sexually acquired, acute hepatitis C were enrolled in this prospective, multicentre trial, and 36 of these patients were treated within the acute phase of hepatitis C infection with pegylated interferon (peg-IFN) therapy.

RESULTS

Early treatment resulted in sustained virological response in 61% of patients. Peg-IFN alone showed similar treatment response rates and lower incidence of anaemia compared with peg-IFN+ribavirin combination therapy. Higher treatment response rates were observed in patients treated over 48 weeks compared with 24 weeks.

CONCLUSIONS

Treatment of hepatitis C in HIV-positive individuals in the acute phase of infection leads to high rates of sustained virological response. Optimal time and mode of therapy have yet to be defined.

Engagement of the B-cell antigen receptor (BCR) allows efficient transduction of ZAP-70-positive primary B-CLL cells by recombinant adeno-associated virus (rAAV) vectors

Engagement of the B-cell antigen receptor (BCR) by crosslinking of the surface immunoglobulin (sIg) homodimer was studied for recombinant adeno-associated virus (rAAV)-mediated gene transfer into B-cell chronic lymphocytic leukaemia (B-CLL) cells. Leukemic cells obtained from 20 patients were stimulated with anti-sIg-directed antibodies and transduced with rAAV vectors coding for enhanced green fluorescent protein (EGFP) (AAV/EGFP) or CD40L (AAV/CD40L). Transduction of B-CLL cells was enhanced after BCR engagement compared to unstimulated controls (P=0.0356). BCR crosslinking induced a significant, dose- and time-dependent upregulation of heparan sulfate proteoglycan (HSPG), the primary receptor for AAV, on B-CLL cells (mean: 38.2 versus 1.7%; P=0.0006). A correlation of HSPG expression after BCR crosslinking with transduction efficiency by AAV/EGFP (P=0.0153) and AAV/CD40L (P=0.0347) was observed. High expression of zeta-associated protein 70 (ZAP-70) in B-CLL cells correlated with a better transduction efficiency by AAV/EGFP (P<0.0001) and AAV/CD40L (P=0.002), respectively: 48 h after transduction of ZAP-70-positive samples, transgene expression was seen in a mean of 33.8% (s.e.m. 3.7%) and 28.9% (s.e.m. 6.7%) of cells, respectively, and could be specifically blocked by heparin, a soluble competitor of HSPG (P<0.0001). In summary, engagement of the BCR on ZAP-70 positive B-CLL cells allows efficient rAAV-mediated gene delivery.