Vascular access type and risk of mortality in a national prospective cohort of haemodialysis patients

BACKGROUND

Central venous catheters (CVC) are a potential source of bacteraemia and have been associated with increased mortality in haemodialysis patients. We aimed to investigate the relationships between haemodialysis vascular access, taking into account changes in vascular access type during patients' lives, and cause specific mortality risk in a national cohort of dialysis patients.

METHODS

Prospective cohort study including all patients receiving haemodialysis in Scotland at annual cross sectional surveys in 2009, 2010 and 2011. Data were collected through the Scottish Renal Registry and by a structured review of case records following death. Cox proportional hazards regression and multivariable logistic regression were used to model survival and risk of death from septicaemia respectively.

RESULTS

Of a cohort of 2666 patients, 873 (32%) died during follow-up. After case-mix adjustment, patients using only tunnelled CVC during follow-up had a higher risk of all cause mortality across all strata of prior renal replacement therapy exposure [adjusted hazard ratio (HR): 1.83-2.08]. Case-mix adjusted risks of cardiovascular death (adjusted HR: 2.20-2.95) and infection-related death (adjusted HR: 3.10-3.63) were also higher in this group. Patients using tunnelled CVCs during follow-up and prior to death had 6.9-fold higher odds of death from septicaemia compared with those using only arteriovenous fistulae or grafts.

CONCLUSION

Compared with an arteriovenous fistula or graft, sustained use of tunnelled CVCs for vascular access is associated with higher risks of all-cause, cardiovascular and infection-related mortality.

Confocal microscopy on the beamline: novel three-dimensional imaging and sample positioning

Confocal microscopy, a technique that has been extensively applied in cellular biological studies, may also be applied to the visualization and three-dimensional imaging of protein crystals at high resolution on synchrotron beamlines. Protein crystal samples are examined using a commercially available confocal microscope adapted for cryogenic use. A preliminary test using a custom confocal design adapted for beamline use is also presented. The confocal optics configuration is compatible with nonlinear imaging techniques such as two-photon excited fluorescence imaging and second harmonic generation. The possibilities of this method are explored using two modes: fluorescence and reflection confocal. In fluorescence mode, small amounts of dye are introduced into the crystal through soaking or growth conditions. Under such conditions, protein crystals are easily resolved from salts and amorphous precipitates, which do not generally take up dye. Reflection mode, which does not require dye, still exhibits greater resolution and sensitivity to surface detail than conventional wide-field microscopy as a result of the confocal optics configuration. The inherent three-dimensional nature of the method means that on-axis sample views (along the direction of the X-ray beam) can be reconstructed from an off-axis configuration, simplifying the beamline setup and providing uniquely detailed views of cryogenically cooled crystals.

New strategies in acute myeloid leukemia: redefining prognostic markers to guide therapy

Although standard therapy for AML has been relatively constant over the past 2 decades, this may be changing with enhanced technologies allowing for the classification of acute myeloid leukemia (AML) into molecularly distinct subsets. Some specific subsets of AML have an excellent prognosis in response to standard therapy, whereas the poor prognosis of AML associated with specific sets of mutations or chromosomal anomalies requires the development of new therapies. Elucidation of the molecular pathogenesis of AML has led to the development of therapies that affect signaling, apoptosis, protein and intermediate metabolism, the surface of the leukemia cell, leukemia cell/stromal interaction, and epigenetic regulation of gene expression.

Stopping clinical trials early for futility: retrospective analysis of several randomised clinical studies

Background:

Many clinical trials show no overall benefit. We examined futility analyses applied to trials with different effect sizes.

Methods:

Ten randomised cancer trials were retrospectively analysed; target sample size reached in all. The hazard ratio indicated no overall benefit (n=5), or moderate (n=4) or large (n=1) treatment effects. Futility analyses were applied after 25, 50 and 75% of events were observed, or patients were recruited. Outcomes were conditional power (CP), and time and cost savings.

Results:

Futility analyses could stop some trials with no benefit, but not all. After observing 50% of the target number of events, 3 out of 5 trials with no benefit could be stopped early (low CP⩽15%). Trial duration for two studies could be reduced by 4–24 months, saving £44 000–231 000, but the third had already stopped recruiting, hence no savings were made. However, of concern was that 2 of the 4 trials with moderate treatment effects could be stopped early at some point, although they eventually showed worthwhile benefits.

Conclusions:

Careful application of futility can lead to future patients in a trial not being given an ineffective treatment, and should therefore be used more often. A secondary consideration is that it could shorten trial duration and reduce costs. However, studies with modest treatment effects could be inappropriately stopped early. Unless there is very good evidence for futility, it is often best to continue to the planned end.

Expression of alternatively spliced variants of Na-Ca-exchanger-1 in experimental colitis: role in reduced colonic contractility

Inflammation-induced colonic motility dysfunction is associated with a disturbance in Ca(2+) ion transporting mechanisms. The main objective of this study was to identify the types of Na-Ca-exchanger-1 (NCX-1) variants expressed in the rat colon, and how this was affected by colitis. In addition, the effect of colitis on the possible involvement of NCX-1 in the reduced carbachol-induced contraction of the rat colon was examined. Colitis was induced in male Sprague-Dawley rats by intra-rectal instillation of trinitrobenzenesulphonic acid (TNBS). Animals were killed on day 5. Colitis was characterized by estimating myeloperoxidase (MPO) activity, body weight, and histological scores. NCX-1 mRNA and protein variants were confirmed by RT-PCR coupled nucleotide sequencing and by Western blot analysis, respectively. Contractility of the colon segments was studied using standard procedure. There was a significant reduction in body weight of TNBS-treated rats. A significant increase in MPO activity and infiltration of inflammatory cells were observed in the inflamed rat colon. RT-PCR coupled nucleotide sequencing identified NCX-1.3 mRNA variant containing exons B and D. Western blot analysis confirmed 70 and 120 kDa molecular mass NCX-1 protein variants in rat colon. There was no significant difference (p > 0.05) in the level of NCX-1 protein variants in inflamed colon as compared to non-colitis controls. Functional experiments demonstrated that NCX in reverse mode played a role in carbachol-induced contraction of colon, and this was not affected by colitis. These findings demonstrated expression of a NCX-1.3 mRNA splice variant, and 70 and 118 kDa protein variants. Inhibition of the reverse mode of NCX-1 was not different in reduced carbachol-induced contraction between the groups. These findings are interpreted to suggest that NCX-1, though expressed did not play a role in reduced contractility in experimental colitis.

Putative Virulence Genes and Biofilm Production Among Typical Enteroaggregative Escherichia coli Isolates from Diarrhoeic Children in Kashmir and Andhra Pradesh

Fifty-eight typical EAEC isolates from children with diarrhoea were examined for HEp-2 cell adherence assay, presence of dispersin (aap), yersiniabactin (irp2), plasmid encoded toxins (pet), Shigella enterotoxin1 (set1A) and cryptic open reading frame (shf) putative virulence genes by polymerase chain reaction as well as for biofilm production. All the isolates showed aggregative adherence pattern on HEp-2 cells. All but five isolates (91.3 %) carried aap gene. While irp2, pet, set1A and shf genes were detected in 68.9, 5.1, 39.6, and 60.3 % isolates, respectively. Thirty-three (64.7 %) isolates out of 51 tested were found to produce biofilm which was found to be significantly associated only with set1A virulence gene (P = 0.025). Highest amount of biofilm was produced by a strain that possessed all the genes studied. Out of 14 isolates in which the most frequent gene combination (aap, irp2 and shf) was observed, only six produced biofilm. It is concluded that there is significant heterogeneity in putative virulence genes of EAEC isolates from diarrhoeic children and biofilm formation is associated with multiple genes.

Glanders in animals: a review on epidemiology, clinical presentation, diagnosis and countermeasures

Glanders or farcy, caused by Burkholderia mallei, is an infectious and zoonotic disease of solipeds. Horses, donkeys and mules are the only known natural reservoir of B. mallei. Although glanders has been eradicated from most countries, it has regained the status of a re-emerging disease because of the numerous recent outbreaks. Pre-symptomatic or carrier animals are the potential source of infection for the healthy equine population and play a crucial role in the spreading of the infectious agent. Glanders is characterized by ulcerating nodular lesions of the skin and mucous membrane. Generalized symptoms include fever, malaise, depression, cough, anorexia and weight loss. Burkholderia mallei can invade its host through mucous membranes, gastrointestinal tract and the integument. Its virulence mechanisms and pathogenesis are not yet completely understood. A major problem when using serological tests for diagnosing glanders is the occurrence of false-positive and false-negative results leading to difficulties in international trade with equids and to the spread of glanders to disease-free regions. Moreover, poor tests critically result in poor control of disease. These tests are not only incapable of discriminating between B. mallei and B. pseudomallei antibodies, they are also unable to differentiate between malleinized and naturally infected animals. Combined use of both serological and molecular detection methods increases the detection rate of glanders. Countermeasures against glanders include early detection of disease in susceptible animals, stringent quarantine measures, testing and safe destruction of infected carcasses, adequate compensation to the animal owners, disinfection of infected premises and awareness about glanders and the zoonotic implications through veterinary extension services. An account of the clinical picture and successful experimental therapy of spontaneous equine glanders is also given.

Myeloid leukemia in Down syndrome

Although adults with Down syndrome (DS) show a decreased incidence of cancer compared to individuals without DS, children with DS are at an increased risk of leukemia. Nearly half of these childhood leukemias are classified as acute megakaryoblastic leukemia (AMKL), a relatively rare subtype of acute myeloid leukemia (AML). Here, we summarize the clinical features of myeloid leukemia in DS, review recent research on the mechanisms of leukemogenesis, including the roles of GATA1 mutations and trisomy 21, and discuss treatment strategies. Given that trisomy 21 is a relatively common event in hematologic malignancies, greater knowledge of how the genes on chromosome 21 contribute to DS-AMKL will increase our understanding of a broader class of patients with leukemia.

Comparative evaluation of three commercially available complement fixation test antigens for the diagnosis of glanders

The sensitivity and specificity of three commercially available complement fixation test (CFT) antigens from c.c.pro (c.c.pro), Central Veterinary Institute of Wageningen UR (CIDC) and the United States Department of Agriculture (USDA) were comparatively evaluated by testing 410 sera collected from glanders-endemic and non-endemic areas (200 true-negative randomly collected sera and 210 sera collected from experimentally immunised animals (12 rabbits, 19 horses), clinically positive (135) and culture-positive (44) horses, donkeys and mules). Immunoblotting (IB) was used as the gold standard test. Highest sensitivity was shown for the CIDC antigen (100 per cent) followed by the c.c.pro antigen (99.39 per cent). However, the USDA antigen showed substantially less (p<0.05) sensitivity (62.19 per cent). Highest specificity was found for the USDA antigen (100 per cent) followed by the CIDC (97.5 per cent) and c.c.pro antigen (96.5 per cent). Positive and negative predictive values (assumed glanders prevalence of <0.1 per cent) for each antigen were calculated to be 95.88 and 99.48 (c.c.pro), 97.04 and 100 (CIDC), 100 and 76.33 per cent (USDA), respectively. Almost perfect agreement (0.96) was found between CFT using either c.c.pro or CIDC and IB.

Wear and surface analysis of 38 mm ceramic-on-metal total hip replacements under standard and severe wear testing conditions

The purpose of this study was to compare the wear of zirconia-toughened alumina (ZTA) and alumina femoral heads tested against as-cast CoCrMo alloy acetabular cups under both standard and severe wear conditions. A new severe test, which included medio-lateral displacement of the head and rim impact upon relocation, was developed. This resulted in an area of metal transfer and an area of increased wear on the superior-anterior segment of the head that were thought to be due to dislocation and rim impact respectively. While the wear of all ceramic heads was immeasurable using the gravimetric method, the wear rates for the metallic cups from each test were readily calculated. An average steady state wear rate of 0.023 ± 0.005 mm3/106 cycles was found for the cups articulating against ZTA under standard wear conditions. A similar result had previously been obtained for the wear of cups articulated against alumina heads of the same size (within the same laboratory). Under severe wear conditions an increase in the metallic cup steady state wear rate was found with the ZTA and alumina tests giving 0.623 ± 0.252 and 1.35 ± 0.154 mm3/106 cycles respectively. Wear of the ceramic heads was detected using atomic force microscopy which showed, under severe wear conditions, a decrease in polishing marks and occasional grain removal. The surfaces of the ZTA heads tested under standard conditions were virtually unchanged from the unworn samples. Friction tests showed low friction factors for all components, pre and post wear.

The changing pattern of referral in acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is not only managed by nephrologists, but also by several other subspecialists. The referral rate to nephrologists and the factors influencing it are unknown.

AIMS

To determine the referral rate, factors affecting referral and outcomes across the spectrum of AKI in a population based study.

METHODS

We identified all patients with serum creatinine concentrations ≥150 µmol/l (male) or ≥130 µmol/l (female) over a 6-month period. AKI was defined according to the RIFLE classification (risk, injury, failure, loss, end stage renal disease [ESRD]). Clinical information and outcomes were obtained from each patient's case records.

RESULTS

A total of 562 patients were identified as having AKI (incidence 2147 per million population/year [pmp/y]). One hundred and sixty-four patients (29%) were referred to nephrologists-referral rate 627 pmp/y. Forty-nine percent of patients whose serum creatinine rose to >300 µmol/l were referred compared with 22% in our previous study of 1997. Forty-eight patients required renal replacement therapy-incidence 184 pmp/y in comparison to 50 pmp/y in our previous study of 1997. Patients had higher odds of referral if they were male, of younger age and were in the F category of the RIFLE classification. Patients had lower odds of referral if they had multiple co-morbid conditions or if they were managed in a hospital without a nephrology service.

CONCLUSION

There has been a significant rise in the referral rate of patients with AKI to nephrologists but even during our period of study only one-third of such patients were being referred. With rising incidence and increased awareness, the referral rate will certainly rise putting a significant burden on the nephrology services.

Absolute configuration of (2S)-4-(4-hydroxyphenyl)butan-2-ol

The title compound, C₁₀H₁₄O₂, was isolated from the chloro­form extract of Taxus wallichiana Zucc. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds, forming sheets parallel to (100). There are weak inter­molecular C—H⋯π inter­actions between the sheets.

Phase II study of AT-101 to abrogate Bcl-2-mediated resistance to androgen-deprivation therapy (ADT) in patients (pts) with newly diagnosed androgen-dependent metastatic prostate cancer (ADMPC)

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Background: Preclinical studies demonstrate that Bcl-2 is over-expressed in most pts with prostate cancer, causes drug resistance to ADT, and that modulation of Bcl-2 improves sensitivity of tumor cells. We are conducting a phase II study for men with ADMPC to test the hypothesis that AT-101, a small molecule Bcl-2 inhibitor, improves clinical results of pts initiating ADT for metastatic prostate cancer. Building on results from SWOG 9346 (Hussain JCO 2006) demonstrating that PSA nadir after 7 mo of ADT predicts survival, we are using a novel phase II trial design, in which the primary endpoint is the percentage of patients with PSA ≤ 0.2 ng/ml at 7 mo of ADT plus AT-101.

Methods: Pts had ADMPC, PSA > 5.0 ng/ml within 12 wks prior to registration and no prior ADT for metastatic disease. ADT with LHRH agonist and bicalutamide started 6 wks prior to initiation of oral AT-101, 20 mg/day for 21 days of 28 day cycle. Pts received up to 8 cycles of ADT and AT-101. A total of 55 pts were enrolled (to obtain 48 evaluable pts) to in a two stage design with null hypothesis 48% versus alternative 68% with PSA ≤ 0.2 at 7 mo. With α = 0.1 and β = 0.9, > 27 pts meeting this endpoint are required to recommend further study.

Results: 55 pts were enrolled, median age 61.5 y; Gleason score (GS) 6 (5%),GS 7 (30%), GS 8 (24%), and GS 9 (41%). 3 pts had visceral mets and the remaining pts had bone or nodal metastasis. 42 pts have discontinued (9 toxicity, 9 progression, 1 withdrew) or completed (n = 23) 7 mo of treatment. In intention to treat analysis, 11 of 42 pts (26%) met the primary endpoint 10, of 42 (23%) pts had PSA > 0.2 and < 4.0 ng/ml after 7 mo. Grade 1/2 toxicities (%) included fatigue (36/9), nausea (20/9), vomiting (13/7), anorexia (15/2), AST/ALT (25/5), hypercalcemia (9/0), constipation (13/3), dry skin (9/0), anemia (18/0), sensory neuropathy (7/7), vomiting (12/7), hyperglycemia (7/4). Grade 3 toxicities were sensory neuropathy 2 pts, GI obstruction 1 pt, syncope 1 pt.

Conclusions: Although final study results are pending the analysis of pts currently on therapy, 26% of pts achieved an undetectable PSA at 7 mo in a population with aggressive disease (66% GS ≥ 8).

No significant financial relationships to disclose.

Changes in Mithun (Bos frontalis) spermatozoa during epididymal passage

Genital organs of 10 healthy, adult Mithun bulls (6-8 years old) that were slaughtered at the dwellings of tribal people for meat were collected. Immediately after collection, spermatozoa from 3 different regions of the epididymis, i.e. the head, body and tail, were obtained to study morphological changes of the spermatozoa during passage through these regions. The prevalence of proximal cytoplasmic droplets significantly decreased from the head to the tail of the epididymis. Conversely, the percentage of distal cytoplasmic droplets increased significantly from the head to the tail region. The incidence of tailless heads rose significantly from head to body and then reduced significantly in the tail region. The percentage of total head abnormalities did, however, not change markedly, but total mid-piece and tail abnormalities differed significantly between the three epididymal regions.