Reversible HLA multimers (Streptamers) for the isolation of human cytotoxic T lymphocytes functionally active against tumor- and virus-derived antigens

The development of MHC/peptide multimers has facilitated the visualization and purification of antigen-specific T cells. However, the persistence of multimers leads to prolonged T cell receptor signaling and subsequently to altered T-cell function. We have recently developed a new type of MHC/peptide multimers, which can be dissociated from the T cell. Herein, we have generated and tested for the first time reversible HLA/peptide multimers, termed Streptamers, for the isolation of human T cells. The Streptamer technique demonstrates the specificity and sensitivity of conventional HLA/peptide tetramers with regards to the sorting of human T lymphocytes. This is shown for T cells directed against immunogenic peptides derived from viral and tumor-associated antigens. We show that antigen-specific cytotoxic T cells remain functionally active following Streptamer dissociation, whereas lytic function and proliferation of the T cells is impaired in the presence of conventional tetramers. These novel HLA/peptide Streptamer reagents allow the isolation of antigen-specific T cells with preserved function and, therefore, facilitate the development of adoptive T cell transfer regimens for the treatment of patients with cancer or infectious diseases.     

An electrophysiological endophenotype of hypomanic and hyperthymic personality

BACKGROUND: Hyperthymic Temperament (HYT) and a closely related trait, Hypomanic Personality (HYP), have both been related to bipolar affective disorder (BAD). Intensity dependence of auditory evoked potentials (IAEP) is a suggested inverse indicator of serotonergic neurotransmission and has been found to be elevated in BAD. Therefore the present study explored for the first time whether subclinical variance of HYT/HYP is also associated with IAEP in a healthy sample. As several traits from biological personality research are correlated with HYT/HYP and also with BAD, the specificity of results against these traits was further analyzed by calculating multiple regression analyses. METHODS: Evoked potentials were recorded from a sample (N=87) homogenous for confounding variables influencing IAEP. For this reason, only 19 to 27-year-old non-smoker psychiatrically healthy male students were included. RESULTS: Significant correlations were found between IAEP and both HYP and HYT. Including Sensation or Novelty Seeking and Extraversion in Regression Analyses did not weaken the associations of HYP with IAEP much, but did affect those of HYT. However, these competing biological personality traits were hardly able to predict IAEP themselves. Impulsivity, though, was able to reduce the predictive power of HYP and HYT and to explain unique IAEP-variance. This was even more the case for Behavioral-Activation-System-Sensitivity (BAS) subscale Fun Seeking clearly dominating all regression analyses. LIMITATIONS: Homogeneity of sample. CONCLUSIONS: The impact of BAS is in agreement with the assumption that heightened BAS-sensitivity is an underlying biological cause for HYP/HYT and for BAD. Future studies on BAD should include BAS and Impulsivity besides HYP/HYT to further explore uniqueness of the latter and to develop questionnaires based on those items of a hyperthymic-hypomanic-impulsive-funseeking item pool, which possess the most external validity.     

Confirmation of recent heroin abuse: Accepting the challenge

Confirmation or exclusion of recent heroin consumption is still one of the major challenges for forensic and clinical toxicologists. A great variety of biomarkers is available for heroin abuse confirmation, including various opium alkaloids (eg, morphine, codeine), street heroin impurities (eg, 6‐acetylcodeine [6‐AC], noscapine, papaverine) as well as associated metabolites (eg, 6‐monoacetylmorphine [6‐MAM], morphine glucuronides). However, the presence of most of these biomarkers cannot solely be attributed to a previous heroin administration but can, among other things, also be due to consumption of poppy seed products (‘poppy seed defense’), opium preparations or specific medications, respectively. A reliable allocation is of great importance in different contexts, for instance in the case of DUID (driving under the influence of drugs) investigations, in driving licence re‐granting processes, in workplace drug testing (WDT), as well as in post‐mortem identification of illicit opiate use. Additionally, differentiation between illicit street heroin abuse and pharmaceutical heroin administration is also important, especially within the frame of heroin‐assisted treatments. Therefore, analysis of multiple biomarkers is recommended when illicit opiate consumption is assumed to obtain the most reliable results possible. Beyond that, interpretation of positive opiate test results requires a profound insight into the great variety of biomarkers available and their validity regarding the alleged consumption. This paper aims to provide an overview of the wide variety of heroin abuse biomarkers described in the literature and to review them regarding their utility and reliability in daily routine analysis.     

Intraoperative Continuous Norepinephrine Infusion Combined with Restrictive Deferred Hydration Significantly Reduces the Need for Blood Transfusion in Patients Undergoing Open Radical Cystectomy: Results of a Prospective Randomised Trial

Background

Open radical cystectomy (ORC) is associated with substantial blood loss and a high incidence of perioperative blood transfusions. Strategies to reduce blood loss and blood transfusion are warranted.

Objective

To determine whether continuous norepinephrine administration combined with intraoperative restrictive hydration with Ringer's maleate solution can reduce blood loss and the need for blood transfusion.

Design, setting, and participants

This was a double-blind, randomised, parallel-group, single-centre trial including 166 consecutive patients undergoing ORC with urinary diversion (UD). Exclusion criteria were severe hepatic or renal dysfunction, congestive heart failure, and contraindications to epidural analgesia.

Intervention

Patients were randomly allocated to continuous norepinephrine administration starting with 2 μg/kg per hour combined with 1 ml/kg per hour until the bladder was removed, then to 3 ml/kg per hour of Ringer's maleate solution (norepinephrine/low-volume group) or 6 ml/kg per hour of Ringer's maleate solution throughout surgery (control group).

Outcome measurements and statistical analysis

Intraoperative blood loss and the percentage of patients requiring blood transfusions perioperatively were assessed. Data were analysed using nonparametric statistical models.

Results and limitations

Total median blood loss was 800 ml (range: 300–1700) in the norepinephrine/low-volume group versus 1200 ml (range: 400–2800) in the control group (p < 0.0001). In the norepinephrine/low-volume group, 27 of 83 patients (33%) required an average of 1.8 U (±0.8) of packed red blood cells (PRBCs). In the control group, 50 of 83 patients (60%) required an average of 2.9 U (±2.1) of PRBCs during hospitalisation (relative risk: 0.54; 95% confidence interval [CI], 0.38–0.77; p = 0.0006). The absolute reduction in transfusion rate throughout hospitalisation was 28% (95% CI, 12–45). In this study, surgery was performed by three high-volume surgeons using a standardised technique, so whether these significant results are reproducible in other centres needs to be shown.

Conclusions

Continuous norepinephrine administration combined with restrictive hydration significantly reduces intraoperative blood loss, the rate of blood transfusions, and the number of PRBC units required per patient undergoing ORC with UD.     

Analysis of promoter methylation in stool: a novel method for the detection of colorectal cancer.

BACKGROUND & AIMS: Detection of tumor-derived DNA alterations in stool is an intriguing new approach with high potential for the noninvasive detection of colorectal cancer (CRC). Because of heterogeneity of tumors, usually multiple markers distributed throughout the human genome need to be analyzed. This is labor intensive and does not allow for high through-put screening. Therefore, markers with high sensitivity and good specificity are needed. We explored the potential of a single epigenetic marker in comparison with fecal occult blood testing (FOBT) for the discrimination of patients with CRCs and adenomas from those without. METHODS: Methylation-specific polymerase chain reaction (PCR) was performed to analyze hypermethylated in cancer 1 (HIC1) promoter methylation status in a blinded fashion in stool samples from 26 patients with CRC, 13 with adenoma > or =1 cm, 9 with hyperplastic polyps, 9 with chronic inflammatory bowel disease, and 32 with endoscopically normal colon. RESULTS: Ninety-seven percent of the stool samples contained amplifiable DNA. Forty-two percent of the samples from patients with CRC and 31% of the samples from patients with colorectal adenoma > or =1 cm were positive for HIC1 promoter methylation. No methylated HIC1 promoter DNA was detected in the fecal DNA from patients with endoscopically normal colon or hyperplastic polyps. CONCLUSIONS: The epigenetic marker HIC1 promoter methylation carries high potential for the remote detection of CRCs. We postulate that a panel of merely a few genetic and epigenetic markers will be required for the highly sensitive and specific detection of CRCs and adenomas in fecal samples from affected patients.     

PROTEIN DISULFIDE ISOMERASE LIKE 5-1 is a susceptibility factor to plant viruses

Protein disulfide isomerases (PDIs) catalyze the correct folding of proteins and prevent the aggregation of unfolded or partially folded precursors. Whereas suppression of members of the PDI gene family can delay replication of several human and animal viruses (e.g., HIV), their role in interactions with plant viruses is largely unknown. Here, using a positional cloning strategy we identified variants of PROTEIN DISULFIDE ISOMERASE LIKE 5–1 (HvPDIL5-1) as the cause of naturally occurring resistance to multiple strains of Bymoviruses. The role of wild-type HvPDIL5-1 in conferring susceptibility was confirmed by targeting induced local lesions in genomes for induced mutant alleles, transgene-induced complementation, and allelism tests using different natural resistance alleles. The geographical distribution of natural genetic variants of HvPDIL5-1 revealed the origin of resistance conferring alleles in domesticated barley in Eastern Asia. Higher sequence diversity was correlated with areas with increased pathogen diversity suggesting adaptive selection for bymovirus resistance. HvPDIL5-1 homologs are highly conserved across species of the plant and animal kingdoms implying that orthologs of HvPDIL5-1 or other closely related members of the PDI gene family may be potential susceptibility factors to viruses in other eukaryotic species.Infectious diseases caused by plant viruses threaten agricultural productivity and reduce globally attainable agricultural production by about 3% (1). In specific pathosystems, plant viruses can result in the loss of the entire crop. For example, the devastation of cassava production by cassava mosaic geminiviruses (CMGs) in Uganda during the 1990s led to widespread food shortages and famine-related deaths (2). Unfortunately protecting plants against viruses (especially soil-borne viruses) by using agrochemicals to control virus vectors is seldom efficient from economic or ecological perspectives. Therefore, crop protection based on naturally occurring virus resistance is key to minimizing losses and achieving sustainable crop yields.Positive-strand RNA viruses represent the largest group of plant viruses (3). They cause a very high proportion of the important infectious virus diseases in agriculture (4, 5). Such plant viruses carry a reduced genome that encodes a limited set of functional proteins (4–10 viral proteins)—insufficient to complete the entire virus replication and proliferation cycle (6). Instead, over evolutionary time, viruses recruited host factors to perform the infectious life cycle (7). This dependence on host factors establishes a possibility that plants can evolve escape, tolerance, or resistance mechanisms to ameliorate the consequences of viral infection. The absence of essential host factors could interfere with the infection process or restrict proliferation (8) leading to either mono- or polygenic recessive resistance (5). Prominent examples of such susceptibility factors that are conserved in multiple plant–virus systems are the EUKARYOTIC TRANSLATION INITIATION FACTORS (EIF)4E, iso4E, 4G, and iso4G (9). Translation initiation factors may interact directly with viral RNA where they catalyze the initiation of translation of viral polyproteins (10, 11). In addition, to establish replication and assembly complexes during infection, viruses typically create membrane-bound environments, referred to as “virus factories” (12). There, cellular chaperones such as HSP70 and DNAJ-like proteins likely contribute to the correct folding and translocation of substrates (12, 13). However, only a few such host factors are known (7, 9, 14).Barley yellow mosaic virus disease caused by barley yellow mosaic virus (BaYMV) and barley mild mosaic virus (BaMMV) (both belong to Bymoviruses) seriously threatens winter barley production in Europe and East Asia (4). Infection leads to yellow discoloration and stunted growth and may result in yield loss of up to 50% (15). Soil-borne transmission via the plasmodiophorid Polymyxa graminis prohibits plant protection by chemical measures, and breeding for resistant cultivars is therefore the only practicable way to prevent yield loss. The naturally occurring recessive resistance locus rym11 confers complete broad-spectrum resistance to all known European isolates of BaMMV and BaYMV (16–19). In the present study, we used a positional cloning strategy to identify the gene underlying rym11-based resistance. We show that it is a susceptibility factor belonging to a gene family of PROTEIN DISULFIDE ISOMERASES (PDIs), and is highly conserved across eukaryotic species. We observe a strong correlation between natural allelic variation and geographic distribution, suggesting that both the origin and subsequent adaptive selection for rym11-based resistance in winter barley occurred in East Asia.