Tracking of activated cTfh cells following sequential influenza vaccinations reveals transcriptional profile of clonotypes driving a vaccine-induced immune response

Introduction

A vaccine against influenza is available seasonally but is not 100% effective. A predictor of successful seroconversion in adults is an increase in activated circulating T follicular helper (cTfh) cells after vaccination. However, the impact of repeated annual vaccinations on long-term protection and seasonal vaccine efficacy remains unclear.

Methods

In this study, we examined the T cell receptor (TCR) repertoire and transcriptional profile of vaccine-induced expanded cTfh cells in individuals who received sequential seasonal influenza vaccines. We measured the magnitude of cTfh and plasmablast cell activation from day 0 (d0) to d7 post-vaccination as an indicator of a vaccine response. To assess TCR diversity and T cell expansion we sorted activated and resting cTfh cells at d0 and d7 post-vaccination and performed TCR sequencing. We also single cell sorted activated and resting cTfh cells for TCR analysis and transcriptome sequencing.

Results and discussion

The percent of activated cTfh cells significantly increased from d0 to d7 in each of the 2016-17 (p < 0.0001) and 2017-18 (p = 0.015) vaccine seasons with the magnitude of cTfh activation increase positively correlated with the frequency of circulating plasmablast cells in the 2016-17 (p = 0.0001) and 2017-18 (p = 0.003) seasons. At d7 post-vaccination, higher magnitudes of cTfh activation were associated with increased clonality of cTfh TCR repertoire. The TCRs from vaccine-expanded clonotypes were identified and tracked longitudinally with several TCRs found to be present in both years. The transcriptomic profile of these expanded cTfh cells at the single cell level demonstrated overrepresentation of transcripts of genes involved in the type-I interferon pathway, pathways involved in gene expression, and antigen presentation and recognition. These results identify the expansion and transcriptomic profile of vaccine-induced cTfh cells important for B cell help.

Increased Frequency of Memory CD4+ T-Cell Responses in Individuals With Previously Treated Extrapulmonary Tuberculosis

Extrapulmonary TB (EPTB) occurs with increased frequency in persons with underlying immunodeficiency. Even after recovery from acute illness, differences in immune phenotype and activation persist. Studies defining characteristics of immune responses after recovery from extrapulmonary TB may provide insights into factors that increase TB risk. We performed two case-control studies (in the United States and Brazil) among HIV-seronegative adults with previous EPTB (n = 9; 25), previous pulmonary TB (n = 7; 25), latent M. tuberculosis (Mtb) infection (n = 11; 25), and uninfected TB contacts (n = 10; 25). We assessed the frequency of dual CD4+ interferon-γ and tumor necrosis factor-α responses after stimulation with overlapping Mtb peptides from ESAT-6 or CFP-10, or gamma-irradiated Mtb H37Rv, proliferative responses to Mtb antigens, T-regulatory cell (Treg) frequency and phenotype. In both study populations, individuals with prior EPTB had the highest frequency of intracellular cytokine-producing cells in response to Mtb antigens (p < 0.05; p <.0001). Persons with prior EPTB in Brazil had the highest levels of CD4 proliferation to Mtb antigens (p < 0.0001), and the highest expression of CD39 on Tregs (p < 0.0001). Individuals with treated EPTB maintained high frequencies of Mtb-specific memory responses and active Treg cells, suggesting that susceptibility to EPTB occurs despite the ability to develop and maintain enhanced adaptive immune responses.

Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g

We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus [B. McKernan, K. E. S. Ford, I. Bartos et al., Astrophys. J. Lett. 884, L50 (2019)AJLEEY2041-821310.3847/2041-8213/ab4886] and is unlikely [<O(0.01%))] due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing or a tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated with S190521g, we find plausible values of total mass M_{BBH}∼100  M_{⊙}, kick velocity v_{k}∼200  km s^{-1} at θ∼60° in a disk with aspect ratio H/a∼0.01 (i.e., disk height H at radius a) and gas density ρ∼10^{-10}  g cm^{-3}. The merger could have occurred at a disk migration trap (a∼700r_{g}; r_{g}≡GM_{SMBH}/c^{2}, where M_{SMBH} is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼1.6  yr(M_{SMBH}/10^{8}  M_{⊙})(a/10^{3}r_{g})^{3/2}.

SUN-544 Immunologic Effects of GLP-1 Activation in Obese Adipose Tissue

Background: Obesity is associated with systemic inflammation which is thought to stem, in part, from adipose tissue (AT). Obese AT is characterized by infiltration of pro-inflammatory T cells that promote macrophage activation and inflammation. GLP-1 has been shown to have anti-inflammatory effects in previous studies. We hypothesized that promotion of GLP-1 signaling with liraglutide or sitagliptin would reduce inflammation in association with an increase in the number of anti-inflammatory invariant natural killer T cells (iNKTs), group 2 innate lymphoid cell (ILC2s) and regulatory T cells (Treg) in blood and AT.

Methods: Obese adults with pre-diabetes were randomized to pharmacologic treatment resulting in increased GLP-1 signaling (liraglutide or sitagliptin, N=8), or hypocaloric diet (N=3). This ongoing study is blinded, so the effects of liraglutide and sitagliptin are combined in analyses and referred to as “drug”. Subcutaneous abdominal AT and peripheral blood mononuclear cells (PBMCs) were collected at baseline (“pre”) and after 12 weeks of therapy (“post”). Phenotypic marker expression of blood and AT T cells were characterized by flow cytometry. Whole AT inflammatory gene expression in the pre and post groups was assessed by Nanostring.

Results: Using the Nanostring inflammation panel, we found that a number of pro-inflammatory genes were significantly downregulated in whole AT after treatment with drug, including CD163, CD86, CCR1, MCP-2, and MCP-4.

Blood ILC2s were significantly decreased with drug treatment (pre 3.95%±3.05, post 1.71% ±1.65, p=0.01), but not diet (pre 2.17% ±1.91, post 1.46% ±1.68, p=0.18). We did not detect a change in Treg numbers after treatment with either diet (pre 5.78% ±1.91, post 6.09% ±1.50, p=0.29) or drug (pre 6.49% ±2.29, post 5.94% ±2.15, p=0.12). Similarly, no difference in blood iNKT numbers was detected after diet (pre 0.063% ±0.044, post 0.082% ±0.049, p=0.11) or drug (pre 0.077% ±0.106, post 0.091% ±0.130, p=0.67).

As observed in the PBMCs, adipose ILC2s were decreased after drug (pre 2.04% ±1.67, post 1.32% ±1.58, p=0.07, N=4). We did not detect a change in AT Treg and iNKT numbers (Treg pre 9.24% ±5.36, post 6.23% ±1.55, p=0.14; iNKT pre 0.12% ±0.08, post 0.09% ±0.05, p=0.47, N=4).

Conclusions: In a small pilot study of obese pre-diabetic patients treated with drugs that activate GLP-1 signaling (liraglutide or sitagliptin) or hypocaloric diet, global transcriptional analysis of whole AT suggested decreased inflammation with drug therapy. However, we found decreased percentages of ILC2 cells (considered anti-inflammatory in adipose) in both blood and AT after drug treatment. Future experiments will further characterize the function of these cell types, and evaluate other immune subsets in PBMC and AT that may be responsible for decreasing inflammation.

Optical polarization properties of (11-22) semi-polar InGaN LEDs with a wide spectral range

Electroluminescence polarization measurements have been performed on a series of semi-polar InGaN light emitting diodes (LEDs) grown on semi-polar (11–22) templates with a high crystal quality. The emission wavelengths of these LEDs cover a wide spectral region from 443 to 555 nm. A systematic study has been carried out in order to investigate the influence of both indium content and injection current on polarization properties, where a clear polarization switching at approximately 470 nm has been observed. The shortest wavelength LED (443 nm) exhibits a positive 0.15 polarization degree, while the longest wavelength LED (555 nm) shows a negative −0.33 polarization degree. All the longer wavelength LEDs with an emission wavelength above 470 nm exhibit negative polarization degrees, and they further demonstrate that the dependence of polarization degree on injection current enhances with increasing emission wavelength. Moreover, the absolute value of the polarization degree decreases with increasing injection current. In contrast, the polarization degree of the 443 nm blue LED remains constant with changing injection current. This discrepancy can be attributed to a significant difference in the density of states (DOS) of the valence subbands.

Monolithically multi-color lasing from an InGaN microdisk on a Si substrate

An optically pumped multi-color laser has been achieved using an InGaN/GaN based micro-disk with an undercut structure on a silicon substrate. The micro-disk laser has been fabricated by means of a combination of a cost-effective microsphere lithography technique and subsequent dry/wet etching processes. The microdisk laser is approximately 1 μm in diameter. The structure was designed in such a way that the vertical components of the whispering gallery (WG) modes formed can be effectively suppressed. Consequently, three clean lasing peaks at 442 nm, 493 nm and 522 nm have been achieved at room temperature by simply using a continuous-wave diode laser as an optical pumping source. Time-resolved micro photoluminescence (PL) measurements have been performed in order to further confirm the lasing by investigating the excitonic recombination dynamics of these lasing peaks. A three dimensional finite-difference-time-domain (FDTD) simulation has been used for the structure design.

Greater activation of peripheral T follicular helper cells following high dose influenza vaccine in older adults forecasts seroconversion

BACKGROUND

Influenza related morbidity and mortality disproportionately impacts older adults. The serologic response to vaccine is diminished in older adults; however, high dose inactivated influenza vaccine (HD IIV) has shown improved rates of seroconversion compared to standard dose (SD IIV). We hypothesize this may be due to the superior ability of high dose vaccine to activate T follicular helper (Tfh) cells and provide B cell dependent T cell help.

METHODS

We measured peripheral Tfh (pTfh) activation in 50 community dwelling adults 65years or older who were randomly assigned to receive either the HD IIV or SD IIV.

RESULTS

The HD vaccination elicited significantly higher levels of ICOS expression on pTfh cells, at day 7 compared to SD vaccination (p=0.02). The magnitude of the increase in ICOS+ pTfh cells from baseline to day 7 was predictive of seroconversion for both influenza A and B vaccination.

CONCLUSION

Strong Tfh activation in response to influenza vaccination forecasts successful seroconversion in older adults, and HD IIV elicits greater Tfh activation than SD IIV. Future vaccine studies should focus on ways to further optimize the Tfh response.

Neither vaginal nor buccal administration of 800 μg misoprostol alters mucosal and systemic immune activation or the cervicovaginal microbiome: a pilot study

OBJECTIVES

The aim of the study was to assess the extent to which misoprostol alters mucosal or systemic immune responses following either buccal or vaginal administration.

METHODS

This was a prospective, crossover pilot study of 15 healthy, reproductive-age women. Women first received 800 μg misoprostol either via buccal or vaginal administration and were crossed over 1 month later to receive the drug via the other route. Cervicovaginal lavage samples, cervical Cytobrush samples, cervicovaginal swabs, urine and blood were obtained immediately prior to drug administration and the following day. Parameters assessed included urine and cervicovaginal misoprostol levels, whole blood cytokine responses (by ELISA) to immune stimulation with lipopolysaccharide, peripheral blood and cervical lymphocyte phenotyping by flow cytometry, cervicovaginal antimicrobial peptide measurement by ELISA and vaginal microbial ecology assessment by 16S rRNA sequencing.

RESULTS

Neither buccal nor vaginal misoprostol significantly altered local or systemic immune and microbiological parameters.

CONCLUSION

In this pilot study, we did not observe significant alteration of mucosal or systemic immunology or vaginal microbial ecology 1 day after drug administration following either the buccal or vaginal route.

Multiparameter analysis of stimulated human peripheral blood mononuclear cells: A comparison of mass and fluorescence cytometry

Mass and fluorescence cytometry are quantitative single cell flow cytometry approaches that are powerful tools for characterizing diverse tissues and cellular systems. Here mass cytometry was directly compared with fluorescence cytometry by studying phenotypes of healthy human peripheral blood mononuclear cells (PBMC) in the context of superantigen stimulation. One mass cytometry panel and five fluorescence cytometry panels were used to measure 20 well-established lymphocyte markers of memory and activation. Comparable frequencies of both common and rare cell subpopulations were observed with fluorescence and mass cytometry using biaxial gating. The unsupervised high-dimensional analysis tool viSNE was then used to analyze data sets generated from both mass and fluorescence cytometry. viSNE analysis effectively characterized PBMC using eight features per cell and identified similar frequencies of activated CD4+ T cells with both technologies. These results suggest combinations of unsupervised analysis programs and extended multiparameter cytometry will be indispensable tools for detecting perturbations in protein expression in both health and disease.

Cocaine enhances HIV-1-induced CD4(+) T-cell apoptosis: implications in disease progression in cocaine-abusing HIV-1 patients

Substance abuse is a major barrier in eradication of the HIV epidemic because it serves as a powerful cofactor for viral transmission, disease progression, and AIDS-related mortality. Cocaine, one of the commonly abused drugs among HIV-1 patients, has been suggested to accelerate HIV disease progression. However, the underlying mechanism remains largely unknown. Therefore, we tested whether cocaine augments HIV-1-associated CD4(+) T-cell decline, a predictor of HIV disease progression. We examined apoptosis of resting CD4(+) T cells from HIV-1-negative and HIV-1-positive donors in our study, because decline of uninfected cells plays a major role in HIV-1 disease progression. Treatment of resting CD4(+) T cells with cocaine (up to 100 μmol/L concentrations) did not induce apoptosis, but 200 to 1000 μmol/L cocaine induced apoptosis in a dose-dependent manner. Notably, treatment of CD4(+) T cells isolated from healthy donors with both HIV-1 virions and cocaine significantly increased apoptosis compared with the apoptosis induced by cocaine or virions alone. Most important, our biochemical data suggest that cocaine induces CD4(+) T-cell apoptosis by increasing intracellular reactive oxygen species levels and inducing mitochondrial depolarization. Collectively, our results provide evidence of a synergy between cocaine and HIV-1 on CD4(+) T-cell apoptosis that may, in part, explain the accelerated disease observed in HIV-1-infected drug abusers.

B cell responses to HIV antigen are a potent correlate of viremia in HIV-1 infection and improve with PD-1 blockade

Infection with Human Immunodeficiency Virus Type 1 (HIV-1) induces defects of both cellular and humoral immune responses. Impaired CD4+ T cell help and B cell dysfunction may partially explain the low frequency of broadly neutralizing antibodies in HIV-infected individuals. To understand the extent of B cell dysfunction during HIV infection, we assessed the level of B cell activation at baseline and after stimulation with a variety of antigens. Increased levels of viremia were associated with higher baseline expression of the activation marker CD86 on B cells and with decreased ability of B cells to increase expression of CD86 after in vitro stimulation with inactivated HIV-1. In a series of cell isolation experiments B cell responses to antigen were enhanced in the presence of autologous CD4+ T cells. HIV infected individuals had a higher frequency of PD-1 expression on B cells compared to HIV- subjects and PD-1 blockade improved B cell responsiveness to HIV antigen, suggesting that inhibitory molecule expression during HIV-1 infection may contribute to some of the observed B cell defects. Our findings demonstrate that during chronic HIV infection, B cells are activated and lose full capacity to respond to antigen, but suppression of inhibitory pressures as well as a robust CD4+ T cell response may help preserve B cell function.

Attainment of metabolic goals in the integrated UK islet transplant program with locally isolated and transported preparations

The objective was to determine whether metabolic goals have been achieved with locally isolated and transported preparations over the first 3 years of the UK's nationally funded integrated islet transplant program. Twenty islet recipients with C-peptide negative type 1 diabetes and recurrent severe hypoglycemia consented to the study, including standardized meal tolerance tests. Participants received a total of 35 infusions (seven recipients: single graft; 11 recipients: two grafts: two recipients: three grafts). Graft function was maintained in 80% at [median (interquartile range)] 24 (13.5-36) months postfirst transplant. Severe hypoglycemia was reduced from 20 (7-50) episodes/patient-year pretransplant to 0.3 (0-1.6) episodes/patient-year posttransplant (p < 0.001). Resolution of impaired hypoglycemia awareness was confirmed [pretransplant: Gold score 6 (5-7); 24 (13.5-36) months: 3 (1.5-4.5); p < 0.03]. Target HbA1c of <7.0% was attained/maintained in 70% of recipients [pretransplant: 8.0 (7.0-9.6)%; 24 (13.5-36) months: 6.2 (5.7-8.4)%; p < 0.001], with 60% reduction in insulin dose [pretransplant: 0.51 (0.41-0.62) units/kg; 24 (13.5-36) months: 0.20 (0-0.37) units/kg; p < 0.001]. Metabolic outcomes were comparable 12 months posttransplant in those receiving transported versus only locally isolated islets [12 month stimulated C-peptide: transported 788 (114-1764) pmol/L (n = 9); locally isolated 407 (126-830) pmol/L (n = 11); p = 0.32]. Metabolic goals have been attained within the equitably available, fully integrated UK islet transplant program with both transported and locally isolated preparations.

Disaster triage after the Haitian earthquake

In the aftermath of the devastating Haitian earthquake, we became the primary relief service for a large group of severely injured earthquake victims. Finding ourselves virtually isolated with extremely limited facilities and a group of critically injured patients whose needs vastly outstripped the available resources we employed a disaster triage system to organize their clinical care. This report describes the specific injury profile of this group of patients, their clinical course, and the management philosophy that we employed. It provides useful lessons for similar situations in the future.

The effect of ergometer design on rowing stroke mechanics

The effect of rowing ergometer design upon power delivery and coordination patterns of the rowing stroke was analyzed for 14 elite rowers. Rowers were tested in three ergometer conditions: the fixed stretcher Concept2c ergometer, the Concept2c ergometer mounted on sliding rails, and the sliding stretcher RowPerfect ergometer. Ergometers were instrumented to measure the external force generated at the handle and the foot stretcher and a nine-segment inverse dynamics model used to calculate joint and overall power delivery. Peak power generation and absorption at the knee joint was significantly greater, and total power delivered to the ergometer delayed on the fixed stretcher ergometer when compared to the sliding stretcher ergometers. No differences were found in the mechanical energy delivered to the handle of the three ergometers; however, greater joint mechanical energy production of the lower limb reduced mechanical efficiency when rowing the Concept2c fixed ergometer. The fixed foot stretcher on the Concept2c fixed ergometer acts to increase the inertial forces that the rower must overcome at the catch, increasing the moment and power output at the knee, and affecting the coordination pattern during the recovery phase.

Soil warming alters nitrogen cycling in a New England forest: implications for ecosystem function and structure

Global climate change is expected to affect terrestrial ecosystems in a variety of ways. Some of the more well-studied effects include the biogeochemical feedbacks to the climate system that can either increase or decrease the atmospheric load of greenhouse gases such as carbon dioxide and nitrous oxide. Less well-studied are the effects of climate change on the linkages between soil and plant processes. Here, we report the effects of soil warming on these linkages observed in a large field manipulation of a deciduous forest in southern New England, USA, where soil was continuously warmed 5°C above ambient for 7 years. Over this period, we have observed significant changes to the nitrogen cycle that have the potential to affect tree species composition in the long term. Since the start of the experiment, we have documented a 45% average annual increase in net nitrogen mineralization and a three-fold increase in nitrification such that in years 5 through 7, 25% of the nitrogen mineralized is then nitrified. The warming-induced increase of available nitrogen resulted in increases in the foliar nitrogen content and the relative growth rate of trees in the warmed area. Acer rubrum (red maple) trees have responded the most after 7 years of warming, with the greatest increases in both foliar nitrogen content and relative growth rates. Our study suggests that considering species-specific responses to increases in nitrogen availability and changes in nitrogen form is important in predicting future forest composition and feedbacks to the climate system.

Dominant clonotypes within HIV-specific T cell responses are programmed death-1high and CD127low and display reduced variant cross-reactivity

HIV epitope-specific T cell responses are often comprised of clonotypic expansions with distinct functional properties. In HIV(+) individuals, we measured programmed death-1 (PD-1) and IL-7Rα expression, MHC class I tetramer binding, cytokine production, and proliferation profiles of dominant and subdominant TCR clonotypes to evaluate the relationship between the composition of the HIV-specific T cell repertoire and clonotypic phenotype and function. Dominant clonotypes are characterized by higher PD-1 expression and lower C127 expression compared with subdominant clonotypes, and TCR avidity positively correlates with PD-1 expression. At low peptide concentrations, dominant clonotypes fail to survive in culture. In response to stimulation with peptides representing variant epitopes, subdominant clonotypes produce higher relative levels of cytokines and display greater capacity for cross-recognition compared with dominant clonotypes. These data indicate that dominant clonotypes within HIV-specific T cell responses display a phenotype consistent with ongoing exposure to cognate viral epitopes and suggest that cross-reactive, subdominant clonotypes may retain greater capacity to suppress replication of viral variants as well as to survive in the absence of strong antigenic signaling.

Patient-reported outcomes following islet cell or pancreas transplantation (alone or after kidney) in Type 1 diabetes: a systematic review

AIMS

For selected individuals with complex Type 1 diabetes, pancreatic islet transplantation (IT) offers the potential of excellent glycaemic control without significant hypoglycaemia, balanced by the need for ongoing systemic immunosuppression. Increasingly, patient-reported outcomes (PROs) are considered alongside biomedical outcomes as a measure of transplant success. PROs in IT have not previously been compared directly with the closest alternate treatment option, pancreas transplant alone (PTA) or pancreas after kidney (PAK).

METHODS

We used a Population, Intervention, Comparisons, Outcomes (PICO) strategy to search Scopus and screened 314 references for inclusion.

RESULTS

Twelve studies [including PRO assessment of PAK, PTA, islet-after kidney (IAK) and islet transplant alone (ITA); n = 7-205] used a total of nine specified and two unspecified PRO measures. Results were mixed but identified some benefits which remained apparent up to 36 months post-transplant, including improvements in fear of hypoglycaemia, as well as some aspects of diabetes-specific quality of life (QoL) and general health status. Negative outcomes included short-term pain associated with the procedure, immunosuppressant side effects and depressed mood associated with loss of graft function.

CONCLUSIONS

The mixed results may be attributable to limited sample sizes. Also, some PRO measures may lack sensitivity to detect actual changes, as they exclude issues and domains of life likely to be important for QoL post-transplantation and when patients may no longer perceive themselves to have diabetes. Thus, the full impact of islet/pancreas transplantation (alone or after kidney) on QoL is unknown. Furthermore, no studies have assessed patient satisfaction, which may highlight further advantages and disadvantages of transplantation.

The relationship between knee adduction moment and cartilage and meniscus morphology in women with osteoarthritis

OBJECTIVE

The aim of this cross-sectional study is to investigate the relationship between knee adduction moment and knee adduction angular impulse and meniscus, cartilage and bone morphology in women with knee osteoarthritis (OA).

METHOD

Forty-five women aged >40 years with OA in at least one knee, according to American College of Rheumatology clinical criteria were studied. The knee joint loading was assessed by three-dimensional motion analysis system during gait. Three Tesla magnetic resonance imaging (MRI) with a coronal T2-weighted spin echo sequence was used for evaluating meniscus pathology, and a coronal T1-weighted gradient echo sequence for quantifying cartilage morphology and bone surface size. Cartilage thickness, denuded area and subchondral area in the femorotibial joint was measured using custom software.

RESULTS

A higher peak knee adduction moment was observed in participants with medial compared to those with lateral tears (2.92+/-1.06 vs -0.46+/-1.7, P<0.001). Participants with a higher knee adduction moment displayed a larger medial meniscus extrusion (r=0.532, P<0.001) and a lower medial meniscus height (r=-0.395, P=0.010). The inverse relationship was observed for the lateral meniscus. A higher knee adduction moment was also associated with a higher ratio of the medial to lateral tibial subchondral bone area (r=0.270, P=0.035). By contrast, cartilage thickness and denuded areas in the femur and tibia were not related to the knee adduction moment. Similar results were found for the relationship between knee adduction angular impulse and meniscus, cartilage and bone morphology.

CONCLUSIONS

Dynamic knee joint loading is significantly related to meniscus pathology and bone size, but not to cartilage thickness in women with OA.

An investigation of medication adherence to 5-aminosalicylic acid therapy in patients with ulcerative colitis, using self-report and urinary drug excretion measurements

BACKGROUND

Non-adherence to 5-aminosalicylic acid (5-ASA) medication can limit the established benefits of this therapy in ulcerative colitis (UC).

AIM

To determine rates and predictors of non-adherence to 5-ASA therapy in UC patients.

METHODS

Medication adherence was assessed using self-report data and urinary drug excretion measurements. Participants completed a study-specific questionnaire and two validated questionnaires: Beliefs about Medicine Questionnaire (BMQ)-Specific and Satisfaction with Information about Medicines Scale.

RESULTS

A total of 169 participants provided self-report adherence data; 151 also provided urine samples. Adherence rates were 111/151 (68%) according to self-report and 90/151 (60%) according to urine analysis, but the two measures were not correlated (chi(2) = 0.12, P = 0.725). Logistic regression identified a significant association between self-reported non-adherence and younger age [odds ratio (OR) for increased age 0.954, 95% confidence interval (CI) 0.932-0.976] and also doubts about personal need for medication (OR for BMQ - Specific Necessity scores 0.578, 95% CI 0.366-0.913). For non-adherence based on urine analysis, only South Asian ethnicity was independently associated with non-adherence (OR 2.940, 95% CI 1.303-6.638).

CONCLUSIONS

Our observations confirm the difficulty of accurately assessing medication adherence. Nonmodifiable (younger age, South Asian ethnicity) and potentially modifiable (medication beliefs) predictors of non-adherence were identified.

Identification of genetic markers associated with residual feed intake and meat quality traits in the pig

Residual feed intake (RFI) has become increasingly important and is being considered as a more reasonable approach to evaluate feed efficiency in livestock. However, the cost and technical difficulties in measuring this trait restrict the extensive adoption of RFI selection, and this makes marker assisted selection (MAS) a feasible tool. In addition, the effects on meat quality caused by low RFI selection have yet to be clarified. In this study, 11 SNPs from eight candidate genes were evaluated in a Yorkshire pig experimental population (n=169) consisting of a low RFI selection line and a randomly selected control line. Associations of these SNPs with RFI, growth rate, carcass composition, and meat quality measures including water holding capacity, pH at 2d postmortem, meat color and sensory traits were analyzed. The SNPs FTO p.Ala198Ala and TCF7L2 c.646+514A>G showed significant (P<0.05) and suggestively significant (P<0.1) associations with RFI, respectively. The MC4R SNP p.Asp298Asn was associated with backfat but it was not with ADG and meat quality attributes. Both SNPs within HNF1A were associated with intramuscular lipid content and sensory juiciness. The SNPs ACC1 c(*)384C>T and TCF7L2 c.646+514A>G were significantly (P<0.05) associated with ADG. The SNPs CTSZ p.Arg64Lys and TCF7L2 c.646+514A>G were associated with both visual scoring of meat color and the objective L-value measure of meat color. This study has identified potential genetic markers suitable for MAS in improving RFI, ADG, and meat color traits, but these associations need to be validated in other larger populations.

Efficacy and stability performance of traditional versus motion sensor-assisted strategies for FES standing

Standing by means of functional electrical stimulation (FES) after spinal cord injury is a topic widely reported in the neurorehabilitation literature. This practice commonly uses surface stimulation over the quadriceps muscle to evoke knee extension. To date, most FES neuroprostheses still operate without any artificial feedback, meaning that after a fatigue-driven knee buckle event, the stimulation amplitude or pulse width must be increased manually via button presses to re-establish knee-lock. This is often referred to as 'hand-controlled (HC) operation'. In an attempt to provide a safer, yet clinically practical approach, this study proposed two novel strategies to automate the control of knee extension based on the kinematic feedback of four miniaturised motion sensors. These strategies were compared to the traditional HC strategy on four individuals with complete paraplegia. The standing times observed over multiple trials were in general longer for the automated strategies when compared to HC (0.5-80%). With the automated strategies, three of the subjects tended to need less upper body support over a frame to maintain balance. A stability analysis based on centre of pressure (CoP) measurements also favoured the automated strategies. This analysis also revealed that although FES standing with the assistance of a frame was likely to be safe for the subjects, their stability was still inferior to that of able-bodied individuals. Overall, the unpredictability of knee buckle events could be more effectively controlled by automated FES strategies to re-establish knee-lock when compared to the traditional user-controlled approach, thus demonstrating the safety and clinical efficacy of an automated approach.

Despite biased TRBV gene usage against a dominant HLA B57-restricted epitope, TCR diversity can provide recognition of circulating epitope variants

The role of epitope-specific TCR repertoire diversity in the control of HIV-1 viremia is unknown. Further analysis at the clonotype level is important for understanding the structural aspects of the HIV-1 specific repertoire that directly relate to CTL function and ability to suppress viral replication. In this study, we performed in-depth analysis of T cell clonotypes directed against a dominantly recognized HLA B57-restricted epitope (KAFSPEVIPMF; KF11) and identified common usage of the TCR beta-chain TRBV7 in eight of nine HLA B57 subjects examined, regardless of HLA B57 subtype. Despite this convergent TCR gene usage, structural and functional assays demonstrated no substantial difference in functional or structural avidity between TRBV7 and non-TRBV7 clonotypes and this epitopic peptide. In a subject where TRBV7-usage did not confer cross-reactivity against the dominant autologous sequence variant, another circulating TCR clonotype was able to preferentially recognize the variant peptide. These data demonstrate that despite selective recruitment of TCR for a conserved epitope over the course of chronic HIV-1 infection, TCR repertoire diversity may benefit the host through the ability to recognize circulating epitope variants.

Immunity, trauma and the elderly

It is believed that an uncontrolled or poorly coordinated immune reaction can be stimulated by major trauma and be responsible for the development of the multiple organ dysfunction syndrome (MODS). The elderly have a reduced ability to mount an effective immune reaction with deficiencies involving both humoral and cellular aspects of immunity that involve poor function of both the stimulatory and immuno-suppressive sides of the immune process. However, there is currently no hard evidence that the excess mortality after major trauma in the elderly is associated with an impaired or excessive immune response. It is possible that their poor resistance to infection is important and immune modulated but the dominant factor in the excess mortality in the elderly population is probably associated with their lack of physiological reserve to respond to a major physiological challenge.

Electrically-evoked control of the swinging leg after spinal cord injury: open-loop or motion sensor-assisted control?

In paraplegics, gait can be restored by means of functional electrical stimulation (FES). Because the electrophysiological responses of the lower limbs to the neuromuscular stimulus are not completely deterministic, several stimulation strategies have been reported in an attempt to refine stepping motion. In open-loop (OL) systems, the electrical stimulation sequences applied over the leg muscles are often tuned for each patient in order to improve the quality of gait. Our aim was to contrast this traditional technique against variable stimulation sequences based on motion sensors (MS) data feedback. Both strategies were tested over 240 stepping trials in three complete paraplegics. In comparison to OL, which used a customised stimulation sequence for each subject, the same MS strategy was as functional for all three subjects. Despite MS producing a lower variability on step lengths, the toe clearances had a similar pattern of variability regardless of the strategy applied. Although the novel MS showed promising results, the reliability of OL was also demonstrated. Therefore, we still recommend the use of OL mainly due to its faster donning and doffing, since this is a matter of importance for the user acceptance of any rehabilitation systems.

Vascular endothelial growth factor as a survival factor for human islets: effect of immunosuppressive drugs

AIMS/HYPOTHESIS

Rapamycin, part of the immunosuppressive regimen of the Edmonton protocol, has been shown to inhibit vascular endothelial growth factor (VEGF) production and VEGF-mediated survival signalling in tumour cell lines. This study investigates the survival-promoting activities of VEGF in human islets and the effects of rapamycin on islet viability.

MATERIALS AND METHODS

Levels of VEGF and its receptors in isolated human islets and whole pancreas was determined by western blotting and immunostaining. Islet viability following VEGF or immunosuppressive drug treatment was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Islet VEGF release was measured by ELISA. Mouse islets infected with an adenovirus expressing the gene for VEGF were transplanted syngeneically into streptozotocin-induced diabetic mice, with blood glucose levels measured three times per week.

RESULTS

Isolated human islets produced multiple isoforms of VEGF and VEGF receptors 1, 2 and 3 and the coreceptor neuropilin 1. Exogenous VEGF (10 ng/ml) prevented human islet death induced by serum starvation, which suggests that VEGF can act as a survival factor for human islets. Transplantation of mouse islets infected with a VEGF-expressing adenovirus in a syngeneic model, improved glycaemic control at day 1 post-transplantation (p < 0.05). Rapamycin at 10 and 100 ng/ml significantly reduced islet VEGF release (by 37 +/- 4% and 43 +/- 6%, respectively; p < 0.05) and at 100 ng/ml reduced islet viability (by 36 +/- 9%) and insulin release (by 47 +/- 7%, all vs vehicle-treated controls; p < 0.05). Tacrolimus had no effect on islet VEGF release or viability.

CONCLUSIONS/INTERPRETATION

Our data suggest that rapamycin may have deleterious effects on islet survival post-transplantation, both through a direct effect on islet viability and indirectly through blockade of VEGF-mediated revascularisation.

Inhalation of glutamic acid decarboxylase 65-derived peptides can protect against recurrent autoimmune but not alloimmune responses in the non-obese diabetic mouse

Systemic administration of islet-derived antigens has been shown to protect against diabetes in the non-obese diabetic (NOD) mouse by the induction of antigen-specific regulatory T cells. Bystander regulation to related and unrelated islet-derived antigens (intramolecular and intermolecular recognition) in this context is recognized. We tested if intranasal administration of glutamic acid decarboxylase 65 (GAD 65)-derived peptides could protect against both autoimmune and, through bystander regulation, alloimmune responses in a NOD mouse model. Spontaneously diabetic female NOD mice underwent islet transplantation from either C57Bl/6 or NOD islet donors. Islet recipients were treated with intranasal GAD 65-derived peptides or control (ovalbumin) peptide pre- and post-transplantation. In-vitro analysis of the effect of inhalation was defined using lymph node proliferation assays and supernatant analysis for cytokines. GAD 65-derived peptide inhalation resulted in significant protection against recurrent autoimmune disease, with the generation of an interleukin (IL)-10-producing immune phenotype in a syngeneic islet transplant model. This phenotype, however, was not robust enough to protect against alloimmune responses. Inhalation of GAD-derived peptides induces an immunoregulatory response that protects against recurrent autoimmune, but not alloimmune responses in the NOD mouse.

Degenerative meniscus tears and mobility impairment in women with knee osteoarthritis

OBJECTIVE

Meniscus tears are often presumed to be associated with a traumatic event, but they can also occur as a result of the cartilage degeneration process in osteoarthritis (OA). The aim of this paper is to describe the prevalence and clinical correlates of degenerative meniscus tears in women with knee OA.

METHOD

The subjects were women screened for a double-blind, sham-exercise controlled clinical trial for women over 40 years of age with OA in at least one knee, according to American College of Rheumatology (ACR) clinical criteria. The presence of meniscus tears was assessed via a 3T Intera (Philips Medical Systems) magnetic resonance image (MRI). Clinical examination included a history of arthritis onset and physical examination of the lower extremities. Physical assessments included body composition, muscle strength, walking endurance, gait velocity, and balance. In addition, pain and disability secondary to OA, physical self-efficacy, depressive symptoms, habitual physical activity level and quality of life were assessed via questionnaires.

RESULTS

Almost three-quarters (73%) of the 41 subjects had a medial, lateral, or bilateral meniscus tear by MRI. Walking endurance and balance performance were significantly impaired in subjects with a degenerative meniscus tear, compared to subjects without tears, despite similar OA duration, symptoms, and disability, body composition, and other clinical characteristics.

CONCLUSION

Meniscus tears, diagnosed by MRI, are very common in older women with knee OA, particularly in the medial compartment. These incidentally discovered tears are associated with clinically relevant impairments of balance and walking endurance relative to subjects without meniscus tears. The explanation for this association requires further study.

Positional effects and strand preference of RNA interference against hepatitis C virus target sequences

The hepatitis C virus (HCV) 3'-untranslated region (UTR) and negative-strand RNA sequences contribute cis-acting functions essential to viral RNA replication. Although efficient suppression of HCV replicon RNA in cell culture has been demonstrated with small interfering RNAs (siRNAs) directed against various sequences in the 5' UTR and coding regions, data regarding siRNA targeting of the 3' UTR have been lacking. Furthermore, it has not been definitively shown whether the active constructs, identified to date, exert their effect exclusively via suppression of the replicon positive strand, negative strand or some combination of both strands. In the present study, we assayed inhibitory activity of various siRNAs targeting the 3' UTR by transient transfection in a subgenomic replicon cell culture model. A survey of 13 candidate target sites in the 3'-UTR X sequence indicated a uniformly low activity of siRNA constructs against the steady-state level of replicon. In contrast, the majority of these same siRNAs exhibited high activity against HCV X sequences of either polarity when these targets were presented in the context of a mammalian polymerase II mRNA transcript. Transfection of siRNAs directed against other regions of the replicon revealed differences in the magnitude of inhibitory effects against positive-strand and negative-strand target sites. Strand preference of siRNA activity was further demonstrated through the introduction of base-pair-destabilizing mutations that promote strand-specific targeting. The results suggest that the HCV positive-strand 5' UTR and coding region are efficiently and directly targeted by siRNA, whereas the 3' UTR and the entire negative strand are relatively resistant to RNA interference.

Health-related behaviours as predictors of mortality and morbidity in Australian Aborigines

OBJECTIVE

To examine predictors of coronary heart disease (CHD) and all-cause mortality in Aboriginal Australians.

METHOD

In 1988-89, a survey of Western Australian Aborigines (256 women, 258 men) aged 15-88 years documented diet, alcohol and smoking habits. Linkage to mortality and hospital admissions to the end of 2002 provided longitudinal data for modelling of coronary heart disease endpoints and all-cause mortality using Cox regression.

RESULTS

Coronary heart disease risk increased with smoking (HR 2.62, 95% CI: 1.19, 5.75), consumption of processed meats >once/week (HR 2.21, 95% CI: 1.05, 4.63), eggs >twice/week (HR 2.59, 95% CI: 1.11, 6.04) and using spreads on bread (HR 3.14. 95% CI: 1.03, 9.61). All-cause mortality risk was lower with exercise >once/week (HR 0.51, 95% CI 0.26, 1.05), increased in ex-drinkers (HR 3.66, 95% CI: 1.08, 12.47), heavy drinkers (HR 5.26, 95% CI: 1.46, 7.52) and with consumption of take away foods >nine times/month (HR 1.78, 95% CI 0.96, 3.29). Greater alcohol intake, smoking and adverse dietary choices clustered in 53% of men and 56% of women and increased risk of coronary heart disease (HR 2.1, 95% CI: 1.1, 4.0) and all-cause mortality (HR 2.3, 95% CI: 1.2, 4.2).

CONCLUSION

Lifestyle in Aboriginal Australians predicts coronary heart disease and all-cause mortality. Clustering of adverse behaviours is common and increases risk of coronary heart disease and death.

Impact of diabetes on haemoglobin levels in renal disease

AIMS/HYPOTHESIS

Anaemia is a common complication of renal impairment. It has been suggested that renal failure secondary to diabetes is associated with more severe anaemia, but this has not been clearly substantiated in the published literature. To clarify this, we undertook a single centre, retrospective study to identify the impact of diabetes on anaemia associated with renal impairment.

MATERIALS AND METHODS

Information on clinical, biochemical and haematological parameters of 2,052 stable ambulatory patients attending a single tertiary referral renal unit was collected. The impact of diabetic kidney disease on haemoglobin levels at all degrees of renal impairment was studied by comparison with patients with non-diabetic kidney disease after correcting for other commonly associated variables that influence anaemia in patients with renal impairment.

RESULTS

Linear regression analysis showed lower haemoglobin in patients with diabetic kidney disease (p < 0.01). At chronic kidney disease (CKD) stages 3, 4 and 5, mean haemoglobin levels in patients with diabetic kidney disease compared with those in patients with non-diabetic kidney disease were 129.5 vs 136.9 g/l (p < 0.001), 120.5 vs 126.9 g/l (p < 0.001) and 107.1 vs 115.9 g/l (p < 0.01), respectively. At CKD stage 4 and 5 the two groups were comparable for ferritin, plasma intact parathyroid hormone levels, ACE inhibitor use and length of follow-up by a nephrologist.

CONCLUSIONS/INTERPRETATION

Diabetic kidney disease is associated with lower haemoglobin in comparison with non-diabetic kidney disease, especially at GFR <60 ml/min.

Metabolism of propionate by sheep liver. Stimulation of the mitochondrial rate by factors from the cell sap

1. The rate of metabolism of propionate by aged sheep-liver mitochondria in the presence of oxygen + carbon dioxide (95:5) was 5.0 (+/- s.e.m. 0.8) mumoles/mg. of mitochondrial N/hr. 2. When aged in the presence of the mitochondrial supernatant the rate was increased. Mitochondria from 0.33g. of liver, when combined with the corresponding mitochondrial supernatant from 0.08g. of liver, metabolized propionate at a rate of 11.4 (+/- s.e.m. 1.2) mumoles/mg. of mitochondrial N/hr. This rate is comparable with rates previously obtained with aged nuclear-free homogenates. 3. Two factors in the mitochondrial supernatant were detected, which when combined reproduced the effect of the fresh supernatant and prevented loss of activity on aging. One of these was non-diffusible and was recovered by fractionation of the dialysed mitochondrial supernatant with ammonium sulphate. The second factor was present in an ultrafiltrate of fresh mitochondrial supernatant and in boiled mitochondrial supernatant; it was isolated and identified as l(+)-glutamate. 4. The effect of the non-diffusible factor was due to protection of the mitochondria from the aging process, whereas glutamate served both in this capacity and as a direct stimulant of propionate metabolism at low concentration.

The pericentriolar recycling endosome plays a key role in Vpu-mediated enhancement of HIV-1 particle release

The HIV-1 accessory gene product Vpu is required for efficient viral particle release from infected human cells. The mechanism by which Vpu enhances particle assembly or release is not yet defined. Here, we identify an intracellular site that is critical for Vpu-mediated enhancement of particle release. Vpu was found to co-localize with markers for the pericentriolar recycling endosome. Expression of dominant negative mutants of Rab11a and myosin Vb that disrupt protein sorting through the recycling endosome abrogated the ability of Vpu to augment particle release. Remarkably, the effects of blocking recycling endosome function on HIV particle release were demonstrable only in human cell lines known to be responsive to Vpu, while no effect on particle release was seen in African green monkey cells. Inhibition of recycling endosome function in human cells also blocked the ability of HIV-2 envelope to enhance particle release. These studies indicate that Vpu and HIV-2 envelope glycoprotein enhance particle release via a common mechanism that requires the activity of the pericentriolar recycling endosome.

Over-expression of AMP-activated protein kinase impairs pancreatic {beta}-cell function in vivo

Treatment of type 1 diabetes by islet transplantation is currently limited by loss of functional beta-cell mass after transplantation. We investigated here whether adenovirus-mediated changes in AMP-activated protein kinase (AMPK) activity, previously shown to affect insulin secretion in vitro, might affect islet graft function in vivo. In isolated mouse and rat islets, insulin secretion stimulated by 17 (vs 3) mmol/l glucose was inhibited by 36.5% (P<0.01) and 43% (P<0.02) respectively after over-expression of constitutively-active AMPK- (AMPK CA) versus null (eGFP-expressing) viruses, and glucose oxidation was decreased by 38% (P<0.05) and 26.6% (P<0.05) respectively. Increases in apoptotic index (terminal deoxynucleotide transferase-mediated deoxyuridine trisphosphate biotin nick end-labelling) (TUNEL)) were also observed in AMPK CA- (22.8 +/- 3.6% TUNEL-positive cells, P<0.001), but not AMPK DN- (2.72 +/- 3.9%, positive cells, P=0.05) infected islets, versus null adenovirus-treated islets (0.68 +/- 0.36% positive cells). Correspondingly, transplantation of islets expressing AMPK CA into streptozotocin-diabetic C57 BL/6 mice improved glycaemic control less effectively than transplantation with either null (P<0.02) or AMPK-DN-infected (P<0.01) islets. We conclude that activation of AMPK inhibits beta-cell function in vivo and may represent a target for therapeutic intervention during islet transplantation.

Radiation exposure to the hands of orthopaedic surgeons: are we underestimating the risk?

INTRODUCTION

Previous studies reported that the radiation exposure to the hands of orthopaedic surgeons was far below the acceptable limit. However, the risk could have been underestimated as some factors were overlooked, namely monitoring trainees during average workload, placing dosimeters over the most susceptible locations, measuring the cumulative dosage of radiation and considering the dose limit for non-classified workers.

MATERIALS AND METHODS

We performed a prospective study in two centres to estimate the radiation dose to the hands of two consultant trauma surgeons and two trainees (one assisting and one operating) while performing 47 fluoroscopy-assisted procedures. We used validated thermoluminescent dosimeters (TLDs) rings and fingerstalls for monitoring the cumulative dosage.

RESULTS

Trainees were at higher risk while performing intramedullary nailing and during assistance. Higher radiation doses were recorded from dominant index fingers and particularly fingertips.

CONCLUSION

The risk of radiation exposure appears to be higher than previously reported. Fingertips are more susceptible to radiation exposure and should therefore be monitored in forthcoming studies.

Double-crush syndrome after acetabular fractures. A sign of poor prognosis

Injury to the sciatic nerve is one of the more serious complications of acetabular fracture and traumatic dislocation of the hip, both in the short and long term. We have reviewed prospectively patients, treated in our unit, for acetabular fractures who had concomitant injury to the sciatic nerve, with the aim of predicting the functional outcome after these injuries. Of 136 patients who underwent stabilisation of acetabular fractures, there were 27 (19.9%) with neurological injury. At initial presentation, 13 patients had a complete foot-drop, ten had weakness of the foot and four had burning pain and altered sensation over the dorsum of the foot. Serial electromyography (EMG) studies were performed and the degree of functional recovery was monitored using the grading system of the Medical Research Council. In nine patients with a foot-drop, there was evidence of a proximal acetabular (sciatic) and a distal knee (neck of fibula) nerve lesion, the double-crush syndrome. At the final follow-up, clinical examination and EMG studies showed full recovery in five of the ten patients with initial muscle weakness, and complete resolution in all four patients with sensory symptoms (burning pain and hyperaesthesia). There was improvement of functional capacity (motor and sensory) in two patients who presented initially with complete foot-drop. In the remaining 11 with foot-drop at presentation, including all nine with the double-crush lesion, there was no improvement in function at a mean follow-up of 4.3 years.

Unusual presentation of sciatica in a 14-year-old girl

The sciatic nerve can be compressed by a variety of causes, while intervertebral disc herniation is the most common cause of sciatica [Surg. Neurol. 46 (1996) 14], other documented causes include, infection, neoplasm, degenerative disease of a spine, congenital anomalies and traumatic posterior hip dislocation [BMJ 287 (1983) 157]. Sciatic neuropathy in children is uncommon. We present an unusual case of sciatic nerve compression in a 14-year-old-girl that was caused by an avulsion fracture of the ischial tuberosity. The compression was relieved by surgical excision of the avulsed ischial tuberosity.

The functional outcome of severe, open tibial fractures managed with early fixation and flap coverage

We studied the outcome and functional status of 33 patients with 34 severe open tibial fractures (Gustilo grade IIIb and IIIc). The treatment regime consisted of radical debridement, immediate bony stabilisation and early soft-tissue cover using a muscle flap (free or rotational). The review included standardised assessments of health-related quality of life (SF-36 and Euroqol) and measurement of the following parameters: gait, the use of walking aids, limb-length discrepancy, knee and ankle joint function, muscle wasting and the cosmetic appearance of the limb. Personal comments and overall patient satisfaction were also recorded. The mean follow-up was 46 months (15 to 80). There were 30 Gustilo grade IIIb fractures and and four grade IIIc fractures. Of the 33 patients, 29 had primary internal fixation and four, external fixation; 11 (34%) later required further surgery to achieve union and two needed bone transport procedures to reconstruct large segmental defects. The mean time to union was 41 weeks (12 to 104). Two patients (6.1%) developed deep infection; both resolved with treatment. The mean SF-36 physical and mental scores were 49 and 62 respectively. The mean state of health score for the Euroqol was 68. Patients with isolated tibial fractures had a better outcome than those with other associated injuries on both scoring systems. Knee stiffness was noted in seven patients (21%) and ankle stiffness in 19 (56%); 12 patients (41%) returned to work. Our results compare favourably with previous outcome measurements published for both limb salvage and amputation. All patients were pleased to have retained their limbs.

Distal femoral fractures: long-term outcome following stabilisation with the LISS

We studied 29 patients with distal femoral fractures stabilised using the less invasive stabilisation system (LISS). Four patients were excluded from the final follow-up (three deaths and one case of quadriplegia). The mean age of the remaining 25 patients (9 males and 16 females) was 60.9 years and the mean follow-up 18 months (range 12-24 months). Eleven patients were tertiary referrals from other hospitals (seven cases were referred due to failure of primary fixation). Overall, there were 12 cases of high-energy trauma (7 open fractures). According to the AO classification, there were 5 Type 33A, 2 Type 33B and 12 Type 33C fractures and 4 Type 32A, 1 Type 32B, 1 Type 32C fractures. Functional assessment was performed using the modified Hospital for Special Surgery (HSS) and the Schatzker and Lambert scores. The average time to union in 22 cases was 3.5 months (range 2-5 months). All of the acute cases united without the need for bone grafting. There were three out of seven cases of non-union in the salvage group still undergoing treatment. The overall result in the acute cases was good and in the salvage cases fair. While this is a small series of patients, our preliminary data indicate favourable results using the LISS in stabilising acute distal femoral fractures. However, when the LISS is used as a revision tool the results seem to be less satisfactory. The system appears to be user-friendly and no technical difficulties were encountered.

The GC–MS detection and characterization of reticuline as a marker of opium use

Reticuline (a precursor of opium alkaloids) was detected and characterised as its trimethylsilyl ethers, acetyl esters and methyl ethers by GC-EIMS and GC-CIMS in opium and the urine of opium users after hydrolysis by acid or beta-glucuronidase as coextractive of morphine. Because this compound cannot be detected in heroin and poppy seeds, it is suggested as a differentiating marker between opium and heroin use, opium and poppy seeds use, or opium and "pharmaceutical" codeine use in cases when opiate use has been confirmed by detection of morphine and codeine in the urine. As well as being a constituent of opium, reticuline in the urine of opium users may also result from the metabolic demethylation of the three other benzyltetrahydroisoquinoline opium alkaloids: codamine, laudanosine and laudanine.

Secondary structure and hybridization accessibility of the hepatitis C virus negative strand RNA 5'-terminus

The positive strand RNA genome of hepatitis C virus (HCV) is transcribed exclusively from a full-length cytoplasmic replication intermediate, the negative strand RNA. Despite this essential role in hepatocellular infection, the negative strand has not yet been subjected to extensive molecular characterization, and in comparison with the HCV genome and proteome, remains relatively unexplored as a target for antiviral therapy. The highly conserved negative strand terminal sequences, complementary to the positive strand 5'- and 3'-untranslated regions, are believed to contribute structural features essential for the initiation of positive strand synthesis and the maintenance of template integrity. We investigated the solution structure of the HCV negative strand 5'-terminal region by endoribonuclease mapping and thermodynamic modelling of RNA secondary structure. The enzymatic probing data are consistent with structural models featuring a large terminal stem loop (SL), which constitutes a mirror image of the complementary 3'-X region SL I structure. Nucleotide positions within the negative strand accessible to hybridization were mapped by RNase H digestion in the presence of combinatorial oligonucleotide libraries. The hybridization data further support the existence of a terminal SL, and reveal target sites within the negative strand 5'-terminus which may be susceptible to antisense-mediated inhibition.

The GC–MS detection and characterization of reticuline as a marker of opium use

Reticuline (a precursor of opium alkaloids) was detected and characterised as its trimethylsilyl ethers, acetyl esters and methyl ethers by GC-EIMS and GC-CIMS in opium and the urine of opium users after hydrolysis by acid or beta-glucuronidase as coextractive of morphine. Because this compound cannot be detected in heroin and poppy seeds, it is suggested as a differentiating marker between opium and heroin use, opium and poppy seeds use, or opium and "pharmaceutical" codeine use in cases when opiate use has been confirmed by detection of morphine and codeine in the urine. As well as being a constituent of opium, reticuline in the urine of opium users may also result from the metabolic demethylation of the three other benzyltetrahydroisoquinoline opium alkaloids: codamine, laudanosine and laudanine.

Viral protein U counteracts a human host cell restriction that inhibits HIV-1 particle production

Human cells resist viral infections by a variety of mechanisms. Viruses must overcome host cell restrictions to successfully reproduce their genetic material. Here, we identify a host restriction to viral replication that acts at the stage of particle assembly. Viral protein U (Vpu) is an HIV-1 accessory protein that enhances particle assembly and release in most human cells, but not in simian cells. By using human-simian cell heterokaryons, we show that the inhibition of assembly in human cells is dominant. Vpu overcomes the block to assembly in human cells and in human-simian heterokaryons. The HIV-1 vpu gene may have evolved to counteract an assembly restriction that is present in human cells.

Structure-based design of hepatitis C virus inhibitors

The limitations of current treatment for chronic hepatitis C virus (HCV) infection have prompted the development of novel therapeutic strategies targeting events specific to viral replication. Over the past decade, advances in the study of HCV molecular biology have led to the identification of cis-acting RNA sequences and viral enzymatic activities which present attractive targets for inhibition. High-resolution, three-dimensional structures of the HCV serine protease, helicase and RNA-dependent RNA polymerase have been determined through X-ray crystallographic studies. More recently, solution structures of these proteins and the HCV internal ribosome entry site have been evaluated by nuclear magnetic resonance spectroscopy and electron microscopy. Mutational analysis and structural characterization of these macromolecules in complex with bound substrates, cofactors and inhibitors has further defined the various electrochemical interactions which mediate protein-protein, protein-RNA and other intermolecular contacts. This review will discuss the available structural data with respect to the rational design of HCV enzyme inhibitors and the development of antisense-based therapeutic strategies, such as RNA interference.

Segmental tibial fractures: an assessment of procedures in 27 cases

Twenty-seven patients (two women) with segmental tibial fractures (19 open) were treated in our institution with a mean age of 38.9 years (range 22-67 years) and a mean Injury Severity Score of 11.5 (9-34). Sixteen fractures were stabilised initially with an interlocking nail, seven with an external fixator, one with a hybrid external fixator, two cases were plated and one was treated in plaster. The mean size of the segment was 11.5 cm (range 4-20 cm). Soft tissue coverage was required in 17 cases. There were three cases of compartment syndrome, six cases of superficial infection and four deep infection cases (two of which required amputation). In four cases, excision of the non-viable segment was necessary. Overall, 13 patients were subjected to a second operative procedure (OP) (four external fixators were replaced with the AO solid tibial nail, two Ilizarov bone transports following excision of the dead bone segment, 2 below knee amputations, 3 exchange reamed nailings, 1 LISS plate application for stability and 1 ring fixator for compression of a fracture). Five patients underwent third procedure (two Ilizarov for bone transport, two exchange nailing, and one bone grafting). The mean time to union of the proximal segment was 38.8 weeks (range 10-78 weeks) and 41.4 weeks (range 12-65 weeks) for the distal segment, respectively. The treatment of segmental tibial fractures poses many problems to the surgeon due to the precarious blood supply of the intermediate segment. The risk of non-union delayed union, infection and additional procedures is high as seen in this series of patients.