Echocardiographic screening for pulmonary arterial hypertension in HIV-positive patients

Human immunodeficiency virus (HIV) infection is associated with an increased risk for pulmonary arterial hypertension (PAH). Upon the screening of 220 asymptomatic HIV-positive individuals by echocardiography, we detected and confirmed HIV-associated PAH in 0.45 % of cases. Mild elevations of systolic pulmonary arterial pressure most probably owing to left ventricular diastolic dysfunction were found in 7.7 % of cases, without progress after 2 years. We suggest that the screening of asymptomatic HIV-positive patients for PAH should not be performed.

Causes of death in HIV-infected patients from the Cologne-Bonn cohort

PURPOSE

Causes of death in human immunodeficiency virus (HIV)-infected subjects have changed in countries with high resources over the last several years. Acquired immunodeficiency syndrome (AIDS)-related diseases have become less prevalent, whereas deaths due to non-AIDS causes are increasing. The aim of the present study was to analyse causes of death in the Cologne-Bonn cohort.

METHODS

Causes of death from the Cologne-Bonn cohort between 2004 and 2010 were systematically recorded using the CoDe algorithm (The Coding Causes of Death in HIV Project).

RESULTS

In 3,165 patients followed from 2004 to 2010, 182 deaths occurred (5.7 %, 153 males, 29 females). The median age at the time of death was 47 years (range 24-85 years). The most frequent causes of death were AIDS-defining events (n = 60, 33 %), with non-Hodgkin lymphoma (NHL) (n = 29, 16 %) and infections (n = 20, 11 %) being the leading entities in this category. Non-AIDS malignancies accounted for 16 % (n = 29), non-HIV-related infections for 10 % (n = 18), cardiovascular diseases for 7 % (n = 14), suicide or accident for 4 % (n = 7) and liver diseases for 3 % (n = 5) of deaths (unknown n = 47, 26 %). Although the majority of patients (92.5 %) was on antiretroviral therapy (ART), only 50 % were virologically suppressed (HIV-RNA <50 copies/mL) and 44 % had a decreased CD4+ count (<200/μL) at their last visit before death.

CONCLUSION

One-third of the causes of death in our cohort between 2004 and 2010 was AIDS-related. Since most of these deaths occur with severe immune suppression, they can possibly be prevented by the early diagnosis and treatment of HIV infection. Care providers must be aware of an increased risk for a broad range of diseases in HIV-infected patients and should apply appropriate preventive measures.

An observational assessment of the sublingual microcirculation of pregnant and non-pregnant women

BACKGROUND

The microcirculation is responsible for distribution of blood within tissues, delivery of oxygen and other nutrients, and regulation of blood pressure. The objective of this study was to compare the sublingual microcirculation of pregnant participants to that of comparable non-pregnant volunteers.

METHODS

Two groups of participants were recruited: a group of pregnant, non-laboring women with singleton pregnancies at term gestation and a control group of age-comparable non-pregnant volunteers. A sidestream dark field imaging device was applied to the sublingual mucosal surface obtaining a steady image for at least 20 s duration, in five visual fields. The resultant five video clips per participant were analyzed blindly and at random to prevent coupling between images. The mean microvascular flow index values for each group were compared using a paired t-test.

RESULTS

Thirty-seven participants were recruited (19 pregnant, 18 non-pregnant); a single pregnant participant was withdrawn because of technical issues. Baseline characteristics were similar with the exception of weight and body mass index. The mean microvascular flow index was significantly higher in the pregnant group 2.7 ± 0.2 compared to the non-pregnant group 2.5 ± 0.3 (P = 0.021), while the perfused vessel density and proportion of perfused vessels were not significantly different (P = 0.707 and 0.403, respectively).

CONCLUSION

The microvascular flow index of pregnant women is higher than a comparable non-pregnant group, which appears to correlate with the physiological changes of pregnancy.

Evaluation of an infectious disease consultation programme in a German tertiary care hospital

PURPOSE

To evaluate a newly implemented infectious disease (ID) consultation service in terms of patient care, outcome and antibiotic prescription and to describe factors influencing adherence to recommendations.

METHODS

Data from consultations during the first 6 months of the ID consultation program were collected and evaluated. Consultation requests, diagnostic results, treatment outcomes and antibiotic recommendations were categorised. Diagnostic and therapeutic recommendations were assessed and rated for adherence and outcome. Statistical analysis was performed to identify factors influencing adherence and treatment outcome.

RESULTS

A total of 251 consultations were assessed. In most cases, ID specialists were asked for further advice regarding a previously initiated anti-infective treatment (N = 131, 52 %). In 54 of 195 (28 %) first consultations, the ID specialist proposed a differential diagnosis that differed from that of the working diagnoses submitted with the consultation request, and which was subsequently confirmed in 80 % of these cases. Diagnostic and therapeutic recommendations were made in 190 (76 %) and 240 (96 %) of the consultations, respectively. A change in the current treatment was recommended in 66 % of consultations; 37 % of recommendations were cost-saving and 26 % were cost-neutral. Compliance with diagnostic and therapeutic recommendations was rated as good by pre-specified criteria in 65 and 86 % of consultations, respectively. Treatment outcome was correlated with adherence to diagnostic recommendations (P = 0.012). Twenty-nine patients (16 %) died during the same hospital stay.

CONCLUSION

Infectious disease consultations may help to establish the correct diagnosis, resulting in the appropriate treatment being provided to a severely sick patient population. Treatment outcome was improved in cases of good diagnostic adherence to the recommendations of the ID specialist.

Alcohol exposure during development: Impact on the epigenome

Fetal alcohol spectrum disorders represent a wide range of symptoms associated with in utero alcohol exposure. Animal models of FASD have been useful in determining the specific neurological consequences of developmental alcohol exposure, but the mechanisms of those consequences are unclear. Long-lasting changes to the epigenome are proposed as a mechanism of alcohol-induced teratogenesis in the hippocampus. The current study utilized a three-trimester rodent model of FASD to examine changes to some of the enzymatic regulators of the epigenome in adolescence. Combined pre- and post-natal alcohol exposureresulted in a significant increase in DNA methyltransferase activity (DNMT), without affecting histone deacetylase activity (HDAC). Developmental alcohol exposure also caused a change in gene expression of regulators of the epigenome, in particular, DNMT1, DNMT3a, and methyl CpG binding protein 2 (MeCP2). The modifications of the activity and expression of epigenetic regulators in the hippocampus of rodents perinatally exposed to alcohol suggest that alcohol's impact on the epigenome and its regulators may be one of the underlying mechanisms of alcohol teratogenesis.

A generic systolic array building block for neural networks with on-chip learning

Neural networks require VLSI implementations for on-board systems. Size and real-time considerations show that on-chip learning is necessary for a large range of applications. A flexible digital design is preferred here to more compact analog or optical realizations. As opposed to many current implementations, the two-dimensional systolic array system presented is an attempt to define a novel computer architecture inspired by neurobiology. It is composed of generic building blocks for basic operations rather than predefined neural models. A full custom VLSI design of a first prototype has demonstrated the efficacy of this design. A complete board dedicated to Hopfield's model has been designed using these building blocks. Beyond the very specific application presented, the underlying principles can be used for designing efficient hardware for most neural network models.

[Doctor-patient interaction: dealing with difficult situations]

Good doctor-patient communication has a positive impact on patient satisfaction, adherence to treatment, health outcomes and well-being, and it has been linked to reduced anxiety, increased recall, and improved understanding. During the diagnostic phase and the course of the illness, patients exhibit a range of mood changes. These include sadness and worry, frustration and anger, uncertainty, fear of disease recurrence, difficulties in inter-personal relationships, changing roles, and concerns about body image. Medical consultations can be influenced by different expectations concerning the doctor-patient interaction, by individual roles and beliefs, and by a different understanding of health and well-being influenced by cultural and other factors not necessarily associated with the medical situation. Responding to anger and other difficult emotions, dealing with family meetings, or communicating via interpreters are often experienced as demanding situations by health care professionals. This article provides an overview of the difficult doctor-patient interactions and illustrates basic communication skills in responding to challenging situations.

Organic cation transporters OCT1 and OCT2 determine the accumulation of lamivudine in CD4 cells of HIV-infected patients

PURPOSE

Identifying factors that determine concentrations of antiretroviral drugs in CD4 cells are important for improving therapeutic efficacy. Experimental models indicate that the nucleoside reverse transcriptase inhibitor lamivudine is transported by the organic cation transporters 1 and 2 (OCT1 and OCT2, respectively). Here, we tested whether OCT1 and OCT2 contribute to the uptake of lamivudine into native CD4 cells of human immunodeficiency virus (HIV)-infected individuals.

METHODS

CD4 cells obtained by non-activated cell sorting from 35 individuals with HIV-1 infection were incubated with lamivudine (10 μM, 30 min), and intracellular concentrations of lamivudine and its active metabolite lamivudine triphosphate were determined by liquid chromatography tandem mass spectrometry. The expression of OCT1 and OCT2 mRNA was measured by quantitative real-time polymerase chain reaction (PCR). A model of OCT2-transfected CD4 cells was established for mechanistic investigations.

RESULTS

Intracellular concentrations of lamivudine and its active metabolite lamivudine triphosphate showed strong linear correlations with each other and with the CD4 mRNA expression of OCT1 and OCT2 (r > 0.80). Coincubation with protease inhibitors (ritonavir, nelfinavir) that inhibit OCT1 and OCT2 yielded decreased intracellular concentrations of lamivudine and lamivudine triphosphate. Incubation of CD4 cells from healthy donors transfected with an OCT2 expression vector yielded increased concentrations of lamivudine and lamivudine triphosphate.

CONCLUSION

Our studies indicate a role of OCT1 and OCT2 for the cellular accumulation of lamivudine in HIV-infected individuals.

A novel cross-talk between endothelin and ErbB receptors controlling glutamate transporter expression in astrocytes

The endothelin and epidermal growth factor (EGF) systems are central to the control of reactive brain processes and are thought to partly exert these tasks by endothelin-induced transactivation of the epidermal growth factor receptor (EGFR) Here we show that beyond EGFR transactivation, endothelins prevent the ligand-induced internalization of the EGFR. We unravel that endothelins abrogate internalization of the EGFR by either promoting the formation of "internalization-deficient" EGFR/ErB2-heterodimers or by activating c-Abl kinase, a negative regulator of EGFR internalization. We further provide evidence that this cross-talk is operational in the control of astrocytic glutamate transport. Specifically, we establish that the inhibitory effects exerted by endothelins on basal as well as EGF-induced expression of the major astroglial glutamate transporter subtype, glutamate transporter 1, are a direct consequence of the endothelin-dependent retention of the EGFR at the cell surface. Together our findings unravel a previously unknown cross-talk between endothelin and epidermal growth factor receptors, which may have implications for a variety of pathological conditions.

Metabolomic analysis as biomarker to study steroid hormone administration in sepsis

Sepsis is a life-threatening disease requiring rapid diagnosis and treatment. Steroid hormones (e.g., estradiol, dehydroepiandosterone) have been suggested to reduce the hyper-inflammatory response of the immune system and to improve outcome in sepsis. We hypothesize that the impact of steroid hormones on the metabolic profile (metabolomic fingerprint) can be used to study and guide steroid hormone administration in sepsis. Potential biomarker candidates are sphingomyelines and phosphatidylcholines.

Liver involvement in HIV-infected patients diagnosed with syphilis

PURPOSE

Liver involvement in syphilis has been studied in cohorts of human immunodeficiency virus (HIV)-negative individuals despite the scarcity of data on such HIV-infected patients. Th aim of this study was to assess hepatic involvement of HIV-infected patients diagnosed with syphilis.

METHODS

Patients with syphilis and liver involvement, including all stages of syphilis, were systematically identified in our HIV cohort between 2004 and 2008.

RESULTS

Of the 1,599 HIV-infected patients identified during the study period, 100 were diagnosed with acute syphilis, all of whom were male. Of these 100 patients, 84% were men who have sex with men. Laboratory parameters of liver involvement were present in 19 of the 100 HIV-infected patients with syphilis; these resolved after successful antibiotic treatment. Among these 19 patients, six were diagnosed to be in the latent stage, with elevated liver enzymes and parameters of inflammation representing the only distinctive feature.

CONCLUSIONS

Based on our results, syphilis should be included in the differential diagnosis of increased liver enzymes in HIV-infected patients.

Long-term beneficial effect of protease inhibitors on the intrinsic apoptosis of peripheral blood mononuclear cells in HIV-infected patients

BACKGROUND

Viral suppression by antiretroviral therapy (ART) inhibits HIV-induced apoptosis and CD4 T-cell loss. It has been suggested that protease inhibitors (PIs) have nonviral antiapoptotic effects by maintaining mitochondrial integrity. Long-term clinical effects of PI-based ART on mitochondrial toxicity and lymphocyte apoptosis beyond viral suppression have not been exploited to date.

METHODS

We conducted a 7-year study on HIV-1-infected patients from the Cologne HIV cohort with sufficient viral suppression under either a PI-based or nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen. Eight patients on PI and eight on NNRTI were eligible for inclusion in the analysis. The primary outcome measure was defined as a change in the mitochondrial-to-nuclear DNA ratio in PBMCs. Further key molecules involved in extrinsic [tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), Fas ligand (FasL) and caspase 8], intrinsic [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase 9 and lactate-to-pyruvate ratio] and overall apoptosis [Annexin+/7-aminoactinomycin D (7-AAD)- and caspase 3/7] and viral activity [negative regulatory factor (Nef), interferon-α (IFN-α) and myxovirus resistance protein A (MxA)] were measured.

RESULTS

Demographic and baseline clinical parameters were similar in the two groups, except that patients in the PI group had a higher mean age. After 7 years of treatment, CD4 T-cell count increased and the expression of genes encoding the proapoptotic viral protein Nef and HIV-induced cytokine IFN-α and its downstream effector MxA decreased in both groups. Focusing on the different pathways of apoptosis, only in the PI group intrinsic apoptosis decreased significant and in the inter-group comparison the decrease was significantly higher than in the NNRTI group.

CONCLUSIONS

Our study provides evidence that long-term therapy with a PI-based regimen may be superior to that with a NNRTI-based regimen with regard to its intrinsic antiapoptotic effect.

Continuous versus intermittent stochastic resonance whole body vibration and its effect on pelvic floor muscle activity

AIMS

To determine the optimal stochastic whole body vibration (SR-WBV) load modality regarding pelvic floor muscle (PFM) activity in order to complete the SR-WBV training methodology for future PFM training with SR-WBV.

METHODS

The continuous and the intermittent SR-WBV modalities were tested by means of electromyography in two independent groups (27 women 8 weeks to 1-year postpartum and 23 women nulliparae or >1-year postpartum) with self-reported stress urinary incontinence. The change in the PFM activity within a single set and over three sets were calculated for both SR-WBV modalities together (time effect) and for both SR-WBV modalities separately (modality-time interaction).

RESULTS

There was no statistically significant or clinically relevant change in PFM activity over time or PFM fatigue in either SR-WBV modality within one or three sets and no difference between the modalities or the groups.

CONCLUSIONS

The lack of change in PFM activity could be due to a no more than moderate to submaximal PFM activity during SR-WBV, the maintenance of reflexive PFM activity despite PFM fatigue or a compensation of slow red PFM fiber fatigue by an increase of innervation frequency and motor unit recruitment of the fast white fibers. As there is no SR-WBV modality dependent difference regarding PFM activity, the continuous modality is recommended in clinical practice as it is easier to apply and less time consuming.

Photoelectron spectromicroscopy at chalcopyrite films

CuInSe₂ films were prepared by MBE on GaAs (111) substrates. ZnSe and ZnO are subsequently deposited in situ by MOMBE. Interface parameters like band offsets and morphology are studied by X-ray photoelectron spectroscopy (XPS) and Low energy electron diffraction (LEED). Spectroscopic XPEEM (X-ray photoelectron emission microscopy) at the U49/2 PGM2 beamline at BESSY was used to investigate the lateral homogenity of the interface. After annealing in situ a lateral inhomogenious In diffusion is observed into the ZnSe/ZnO interface.