The HIV 5′ Gag Region Displays a Specific Nucleotide Bias Regulating Viral Splicing and Infectivity

Alternative splicing and the expression of intron-containing mRNAs is one hallmark of HIV gene expression. To facilitate the otherwise hampered nuclear export of non-fully processed mRNAs, HIV encodes the Rev protein, which recognizes its intronic response element and fuels the HIV RNAs into the CRM-1-dependent nuclear protein export pathway. Both alternative splicing and Rev-dependency are regulated by the primary HIV RNA sequence. Here, we show that these processes are extremely sensitive to sequence alterations in the 5’coding region of the HIV genomic RNA. Increasing the GC content by insertion of either GFP or silent mutations activates a cryptic splice donor site in gag, entirely deregulates the viral splicing pattern, and lowers infectivity. Interestingly, an adaptation of the inserted GFP sequence toward an HIV-like nucleotide bias reversed these phenotypes completely. Of note, the adaptation yielded completely different primary sequences although encoding the same amino acids. Thus, the phenotypes solely depend on the nucleotide composition of the two GFP versions. This is a strong indication of an HIV-specific mRNP code in the 5′ gag region wherein the primary RNA sequence bias creates motifs for RNA-binding proteins and controls the fate of the HIV-RNA in terms of viral gene expression and infectivity.     

Influence of residual stenosis after percutaneous coronary intervention with stent implantation on development of restenosis and stent thrombosis

The aim of this study was to assess the effects of residual stenosis after single-stent implantation on the rate of stent thrombosis, as well as restenosis within a 6-month follow-up period. Coronary angiograms of 2,157 patients with 2,523 lesions treated with a single stent were analyzed by quantitative coronary angiography before, immediately after stent implantation, and at a planned 6-month follow-up. Lesions were classified into 4 subgroups according to the degree of residual stenosis after stent implantation: group 1, gross oversizing <-15%; group 2, slight oversizing -15% to <0%; group 3, mild residual 0% to <15%; group 4, moderate residual 15% to <30%. Stent thrombosis rates were not significantly different among the 4 subgroups (group 1: 0 of 60 [0%]; group 2: 2 of 388 [0.5%]; group 3: 8 of 1,370 [0.6%]; group 4: 8 of 705 [1.1%]; p = NS for all). An adequate dosage of ticlopidine (250 mg twice daily) and aspirin (100 mg/day) led to a lower rate of stent thrombosis (6 of 2,189 cases) than inadequate dosages or missing therapy (12 of 343 cases). In 1,882 stenoses with angiographic follow-up (77.7%), gross oversizing of stents lead to a significantly higher increase of percent stenosis (p <0.001) associated with a higher restenosis rate (group 1: 34.7% vs groups 2, 3, and 4: 32.5%, 28.2%, and 29.6%, respectively). A multiple regression analysis was performed. Optimal results with regard to stent thrombosis and restenosis were achieved with mild residual stenoses between 0% and 15% after stent implantation. Oversizing of stents is no longer necessary with an adequate dosage of ticlopidine and aspirin.     

The human olfactory receptor gene family

Humans perceive an immense variety of chemicals as having distinct odors. Odor perception initiates in the nose, where odorants are detected by a large family of olfactory receptors (ORs). ORs have diverse protein sequences but can be assigned to subfamilies on the basis of sequence relationships. Members of the same subfamily have related sequences and are likely to recognize structurally related odorants. To gain insight into the mechanisms underlying odor perception, we analyzed the human OR gene family. By searching the human genome database, we identified 339 intact OR genes and 297 OR pseudogenes. Determination of their genomic locations showed that OR genes are unevenly distributed among 51 different loci on 21 human chromosomes. Sequence comparisons showed that the human OR family is composed of 172 subfamilies. Types of odorant structures that may be recognized by some subfamilies were predicted by identifying subfamilies that contain ORs with known odor ligands or human homologs of such ORs. Analysis of the chromosomal locations of members of each OR subfamily revealed that most subfamilies are encoded by a single chromosomal locus. Moreover, many loci encode only one or a few subfamilies, suggesting that different parts of the genome may, to some extent, be involved in the detection of different types of odorant structural motifs.     

Diagnosis of lyme borreliosis in europe

In Europe, Lyme borreliosis is caused by at least three species, B. burgdorferi sensu stricto, B. afzelii and B. garinii. Thus microbiological diagnosis in European patients must consider the heterogeneity of Lyme disease borreliae for development of diagnostic tools such as PCR primers and diagnostic antigens. According to guidelines of the German Society of Hygiene and Microbiology, the serological diagnosis should follow the principle of a two-step procedure. A sensitive ELISA differentiating IgM and IgG is recommended as the first step. In case the ELISA is reactive, it is followed by immunoblots (IgM and IgG) as the second step. The reactive diagnostic bands should be clearly identified, which is easy if recombinant antigens are used. The sensitivity and standardization of immunoblots has been considerably enhanced by use of recombinant antigens instead of whole cell lysates. Improved sensitivity resulted from use of recombinant proteins that are expressed primarily in vivo (e.g., VlsE) and combination of homologous proteins from different strains of borrelia (e.g., DbpA). It also appears promising to use recombinant proteins (DbpA, VlsE, others) or synthetic peptides (the conserved C6 peptide derived from VlsE) as ELISA antigens. At present, detection rates for serum antibodies are 20-50% in stage I, 70-90% in stage II, and nearly 100% in stage III Lyme disease. The main goals for the future are to improve specificity in general and sensitivity for diagnosis of early manifestations (stage I and II). Detection of the etiological agent by culture or PCR should be confined to specific indications and specialised laboratories. Recommended specimens are skin biopsy specimens, CSF and synovial fluid. The best results are obtained from skin biopsies with culture or PCR (50-70%) and synovial tissue or fluid (50-70% with PCR). CSF yields positive results in only 10-30% of patients. Methods that are not recommended for diagnostic purposes are antigen tests in body fluids, PCR of urine, and lymphocyte transformation tests.     

Clonal accumulation of activated CD8+ T cells in the central nervous system during the early phase of neuroborreliosis

Borrelia burgdorferi may cause an acute infection of the central nervous system (CNS) that rarely leads to chronic disease. To characterize host immunity to B. burgdorferi in humans, we performed serial T cell receptor (TCR) variable beta (TCRBV) chain analyses in blood and cerebrospinal fluid (CSF) samples from 10 patients with acute neuroborreliosis. In most patients, we found significant differences in TCRBV expression between CSF and peripheral blood T cells, predominantly involving CD8(+) T cells. T cells that accumulated in the CSF had a memory phenotype and expressed high levels of C-C chemokine receptor 5 and CD69. Serial studies demonstrated that CD8(+) T cell accumulation decreased continuously after resolution of the infection. In 2 patients, serial analysis of the TCR-alpha and -beta chain sequences revealed that overexpression of TCRBV in CSF was caused by extensive clonal expansion of CD8(+) T cells. Our findings support the role of CD8(+) T cells during the early host defense against spirochete infection of the CNS.     

Effect of ambulatory blood pressure measurement on sleep in patients with a major depressive episode

BACKGROUND: To assess the effects of ambulatory blood pressure measurement (ABPM) upon sleep in mentally depressed patients with near absence of deep (stage 3 and 4) sleep. METHODS: Twelve depressed patients aged 50.5+/-13.5 (21-item Hamilton Depression Rating Scale: 23.8+/-5.1) were studied on three consecutive nights in the sleep laboratory. In a random order, blood pressure was measured with a portable device over 24 h on either day 2 or 3. Polysomnographic data were analysed according to the criteria of Rechtschaffen and Kales. RESULTS: Compared to the control night, there was a significant increase of awakenings during the ABPM night. However, total sleeping time as well as sleep efficiency remained unchanged. Percentage of nocturnal decrease in both systolic and diastolic blood pressure was unrelated to the number of arousals. CONCLUSION: In depressed patients with severe disturbances of sleep architecture, ABPM did not lead to a prolongation of time awake or decrease in sleep efficiency.     

MHC class II-expressing hepatocytes function as antigen-presenting cells and activate specific CD4 T lymphocyutes

The ability to activate CD4 T cells is restricted to antigen-presenting cells that express major histocompatibility complex (MHC) class II molecules. Parenchymal cells normally do not express MHC class II molecules; however, in clinical hepatitis, viral or autoimmune, hepatocytes often exhibit aberrant MHC class II expression. It is not known whether MHC class II-expressing hepatocytes can function as antigen-presenting cells, but it has been suggested that aberrant MHC class II expression by parenchymal cells may cause autoimmune disease. Therefore, we generated transgenic mice that specifically overexpress class II transactivator molecules in hepatocytes. Hepatocytes from these mice exhibited stable MHC class II expression and were used to stimulate CD4 T cells from T-cell receptor transgenic mice and CD4 T-cell lines. MHC II-expressing hepatocytes featured costimulatory CD80 molecules and could serve as antigen-presenting cells that were able to process protein antigen and to activate specific CD4 T cells. Nevertheless, the transgenic mice with aberrant hepatocellular MHC class II expression did not exhibit any symptoms of autoimmune disease. In conclusion, MHC II-expressing hepatocytes, as found in clinical hepatitis, can present antigen and activate CD4 T cells. The ability of hepatocytes to present antigen on MHC II molecules does not seem to be a sufficient cause for inflammatory autoimmunity and hepatitis. However, we still need to explore whether such antigen presentation is occurring in vivo. The transgenic mice described in this study may serve as a model to study the immune interaction of hepatocytes and CD4 T cells in both in vitro and in vivo.     

Intralymphatic allergen administration renders specific immunotherapy faster and safer: A randomized controlled trial

The only causative treatment for IgE-mediated allergies is allergen-specific immunotherapy. However, fewer than 5% of allergy patients receive immunotherapy because of its long duration and risk of allergic side effects. We aimed at enhancing s.c. immunotherapy by direct administration of allergen into s.c. lymph nodes. The objective was to evaluate safety and efficacy compared with conventional s.c. immunotherapy. In a monocentric open-label trial, 165 patients with grass pollen-induced rhinoconjunctivitis were randomized to receive either 54 s.c. injections with pollen extract over 3 years [cumulative allergen dose 4,031,540 standardized quality units (SQ-U)] or 3 intralymphatic injections over 2 months (cumulative allergen dose 3,000 SQ-U). Patients were evaluated after 4 months, 1 year, and 3 years by nasal provocation, skin prick testing, IgE measurements, and symptom scores. Three low-dose intralymphatic allergen administrations increased tolerance to nasal provocation with pollen already within 4 months (P < 0.001). Tolerance was long lasting and equivalent to that achievable after standard s.c. immunotherapy (P = 0.291 after 3 years). Intralymphatic immunotherapy ameliorated hay fever symptoms (P < 0.001), reduced skin prick test reactivity (P < 0.001), decreased specific serum IgE (P < 0.001), caused fewer adverse events than s.c. immunotherapy (P = 0.001), enhanced compliance (P < 0.001), and was less painful than venous puncture (P = 0.018). In conclusion, intralymphatic allergen administration enhanced safety and efficacy of immunotherapy and reduced treatment time from 3 years to 8 weeks.     

Does regular zoledronic acid change the bone turnover of the jaw in men with metastatic prostate cancer: A possible clue to the pathogenesis of bisphosphonate related osteonecrosis of the jaw?

Purpose

To find out whether the most popular pathogenesis hypothesis of the bisphosphonate (BP) related osteonecrosis of the jaw (BRONJ) is comprehensible: (1) is there a higher bone remodeling in the jaw compared with other skeletal sites? (2) Is the bone turnover (BT) of the jaw overly altered after BP intake? (3) Are there gender- or entity-specific differences in BT before and after BP intake?

Methods

Bone scintigraphies of 42 patients with prostate cancer were retrospectively analyzed (n = 21 with BP intake; n = 21 no BP). All patients received bone scintigraphy prior to the therapy and in the course of the treatment (after 12 and 24 months). Data were quantitatively analyzed using six predetermined regions of interest and compared with a breast cancer cohort.

Results

The mandible revealed a similar BT as the femur and a significant lower BT compared with the maxilla. All investigated bone regions showed no significant changes under BP administration. Inter-gender differences revealed significantly lower BT values for the prostate cancer compared with the female breast cancer cohort, changes over the course of time could not be found.

Conclusions

The finding that the mandible revealed a significant lower BT than the maxilla and the fact that 2/3 of the BRONJ cases occur in the mandible are inconsistent with the investigated hypothesis. Furthermore, the BT in the jawbone is not overly suppressed by BP. Thus, it seems implausible that a high BT and its over-suppression play the key role in the pathomechanism of BRONJ.