Indicator microbes correlate with pathogenic bacteria, yeasts and helminthes in sand at a subtropical recreational beach site

AIMS

Research into the relationship between pathogens, faecal indicator microbes and environmental factors in beach sand has been limited, yet vital to the understanding of the microbial relationship between sand and the water column and to the improvement of criteria for better human health protection at beaches. The objectives of this study were to evaluate the presence and distribution of pathogens in various zones of beach sand (subtidal, intertidal and supratidal) and to assess their relationship with environmental parameters and indicator microbes at a non-point source subtropical marine beach.

METHODS AND RESULTS

In this exploratory study in subtropical Miami (Florida, USA), beach sand samples were collected and analysed over the course of 6 days for several pathogens, microbial source tracking markers and indicator microbes. An inverse correlation between moisture content and most indicator microbes was found. Significant associations were identified between some indicator microbes and pathogens (such as nematode larvae and yeasts in the genus Candida), which are from classes of microbes that are rarely evaluated in the context of recreational beach use.

CONCLUSIONS

Results indicate that indicator microbes may predict the presence of some of the pathogens, in particular helminthes, yeasts and the bacterial pathogen Staphylococcus aureus including methicillin-resistant forms. Indicator microbes may thus be useful for monitoring beach sand and water quality at non-point source beaches.

SIGNIFICANCE AND IMPACT OF THE STUDY

The presence of both indicator microbes and pathogens in beach sand provides one possible explanation for human health effects reported at non-point sources beaches.

Fast scanning probe for the NSTX spherical tokamak

We describe a fast reciprocating Langmuir probe and drive system, which has four main new features: (1) use of high-temperature, vacuum, circuit boards instead of cables to reduce weight and increase to 21 the number of possible connections, (2) rotatable and removable shaft, (3) 10 tip construction with designed hardware bandwidth up to 10 MHz, and (4) a detachable and modular tip assembly for easy maintenance. The probe is mounted in a fast pneumatic drive capable of speeds approximately 7 m/s and approximately 20g's acceleration in order to reach the scrape-off layer (SOL) and pedestal regions and remain inserted long enough to obtain good statistics while minimizing the heat deposition to the tips and head in a power density environment of 1-10 MW/m2. The National Spherical Torus Experiment SOL features electron temperature, T(e) approximately 10-30 eV, and electron density, n(e) approximately 0.1-5x10(12) cm(-3) while the pedestal features n(e) approximately 0.5-1.5x10(13) cm(-3) and T(e) approximately 30-150 eV. The probe described here has ten tips which obtain a wide spectrum of plasma parameters: electron temperature profile T(e)(r), electron density profile n(e)(r) and Mach number profile M(r), floating potential V(f)(r), poloidal and radial electric field profiles E(theta)(r) and E(rho)(r), saturation current profile I(sat)(r), and their fluctuations up to 3 MHz. We describe the probe and show representative radial profiles of various parameters.

Harmonisation of ethics committees' practice in 10 European countries

BACKGROUND

The Directive 2001/20/EC was an important first step towards consistency in the requirements and processes for clinical trials across Europe. However, by applying the same rules to all types of drug trials and transposing the Directive's principles into pre-existing national legislations, the Directive somewhat failed to meet its facilitation and harmonization targets. In the field of ethics, the Directive 2001/20/EC conditioned the way of understanding and transposing the "single opinion" process in each country. This led to a situation in which two models of research ethics committees organisation systems exist, being the model in which the "single opinion" is considered to be the decision made by a single ethics committee more effective and simpler in terms of administrative and logistic workload.

METHOD

A survey was conducted in 10 European countries. Members of the European Clinical Research Infrastructures Network working party number 1, with expertise in the field of ethics, responded.

RESULTS

There is a major heterogeneity in the composition of ethics committees among the surveyed countries based on the number of members, proportion of experts versus lay members and expertise of the scientific members. A harmonized education of the ethics committees' membership based in common curricula is recommended by the majority of countries.

CONCLUSIONS

Despite the efforts for harmonization of the European Clinical Trial Directive, from an ethical point of view, there remains a plurality of ethics committees' systems in Europe. It is important to comprehend the individual national systems to understand the problems they are facing.

Feasibility of intravascular ultrasound studies: predictors of imaging success before coronary interventions

BACKGROUND

Intravascular ultrasound (IVUS) is currently used to study lesions during transcatheter coronary therapy. However, before dilation some lesions cannot be reached or crossed with the imaging catheter.

HYPOTHESIS

This study seeks to elucidate which factors determine the feasibility of IVUS examination before coronary interventions.

METHODS

Accordingly, 100 consecutive patients undergoing IVUS examination before coronary angioplasty were prospectively studied. The clinical and angiographic characteristics of 77 patients with a successful IVUS study (Group A) were compared with those of 23 patients in whom IVUS was attempted but the target lesion could not be interrogated (Group B). The echogenic characteristics of the target lesion [before (n = 77) or after intervention (in 18 patients in Group B)] were also studied.

RESULTS

Patients in Group B were significantly older (62 +/- 7 vs. 57 +/- 10 years, p < 0.05) and more frequently had stable angina [8 (35%) vs. 9 (11%), p < 0.05]. The distribution of lesions within the coronary tree and angiographic lesion characteristics including length, eccentricity, calcification, bend location, and the American College of Cardiology/American Heart Association classification were similar in both groups. However, proximal tortuosities (> 45 degrees at end diastole) were more frequently found in Group B [20 (87%) vs. 47 (61%), p < 0.05]. In addition, by quantitative angiography, patients in Group B had smaller arteries (reference diameter 2.8 +/- 0.4 vs. 3.1 +/- 0.4 mm, p < 0.05) and more severe lesions (minimal lumen diameter 0.46 +/- 0.24 vs. 0.65 +/- 0.34 mm, p < 0.05). On IVUS, calcified lesions were more frequently visualized in Group B (61 vs. 38%, p < 0.05). On multivariate analysis, catheter size, baseline minimal lumen diameter, angiographic proximal tortuosities, and lesion calcification on imaging were independent predictors of the feasibility of IVUS studies.

CONCLUSIONS

Unsuccessful IVUS studies before intervention occur more frequently (1) in vessels with proximal tortuosities or severe lumen narrowing, (2) in lesions that are calcified on IVUS, and (3) when large imaging catheters are used.

[Extra-anatomic aortic bypass for repair of aortic arch diseases in adults]

Surgical management of aortic arch diseases in the adult are challenging. Use of extra-anatomic conduits are a well established form of treatment. We report a retrospective study of four patients operated on in our institution between 2000 and 2006, using this technique. Two patients had a median sternotomy, one a left thoracotomy and one a right thoracotomy. There were no perioperative mortality and all patients were alive and doing well after a mean follow-up of 19 months. In this subset of patients, surgical treatment should be individualized. In our experience, extra-anatomic bypass is a valuable, effective and safe surgical option.

Clinical effectiveness and cost-effectiveness of laparoscopic surgery for colorectal cancer: systematic reviews and economic evaluation

OBJECTIVE

The aim of this study was to determine the clinical effectiveness and cost-effectiveness of laparoscopic, laparoscopically assisted (hereafter together described as laparoscopic surgery) and hand-assisted laparoscopic surgery (HALS) in comparison with open surgery for the treatment of colorectal cancer.

DATA SOURCES

Electronic databases were searched from 2000 to May 2005. A review of economic evaluations was undertaken by the National Institute for Health and Clinical Excellence in 2001. This review was updated from 2000 until July 2005.

REVIEW METHODS

Data from selected studies were extracted and assessed. Dichotomous outcome data from individual trials were combined using the relative risk method and continuous outcomes were combined using the Mantel-Haenszel weighted mean difference method. Summaries of the results from individual patient data (IPD) meta-analyses were also presented. An economic evaluation was also carried out using a Markov model incorporating the data from the systematic review. The results were first presented as a balance sheet for comparison of the surgical techniques. It was then used to estimate cost-effectiveness measured in terms of incremental cost per life-year gained and incremental cost per quality-adjusted life-year (QALY) for a time horizon up to 25 years.

RESULTS

Forty-six reports on 20 studies [19 randomised controlled trials (RCTs) and one IPD meta-analysis] were included in the review of clinical effectiveness. The RCTs were of generally moderate quality with the number of participants varying between 16 and 1082, with 10 having less than 100 participants. The total numbers of trial participants who underwent laparoscopic or open surgery were 2429 and 2139, respectively. A systematic review of four papers suggested that laparoscopic surgery is more costly than open surgery. However, the data they provided on effectiveness was poorer than the evidence from the review of effectiveness. The estimates from the systematic review of clinical effectiveness were incorporated into a Markov model used to estimate cost-effectiveness for a time horizon of up to 25 years. In terms of incremental cost per life-year, laparoscopic surgery was found to be more costly and no more effective than open surgery. With respect to incremental cost per QALY, few data were available to differentiate between laparoscopic and open surgery. The results of the base-case analysis indicate that there is an approximately 40% chance that laparoscopic surgery is the more cost-effective intervention at a threshold willingness to pay for a QALY of pound 30,000. A second analysis assuming equal mortality and disease-free survival found that there was an approximately 50% likelihood at a similar threshold value. Broadly similar results were found in the sensitivity analyses. A threshold analysis was performed to investigate the magnitude of QALY gain associated with quicker recovery following laparoscopic surgery required to provide an incremental cost per QALY of pound 30,000. The implied number of additional QALYs required would be 0.009-0.010 compared with open surgery.

CONCLUSIONS

Laparoscopic resection is associated with a quicker recovery (shorter time to return to usual activities and length of hospitalisation) and no evidence of a difference in mortality or disease-free survival up to 3 years following surgery. However, operation times are longer and a significant number of procedures initiated laparoscopically may need to be converted to open surgery. The rate of conversion may be dependent on experience in terms of both patient selection and performing the technique. Laparoscopic resection appears more costly to the health service than open resection, with an estimated extra total cost of between pound 250 and pound 300 per patient. In terms of relative cost-effectiveness, laparoscopic resection is associated with a modest additional cost, short-term benefits associated with more rapid recovery and similar long-term outcomes in terms of survival and cure rates up to 3 years. Assuming equivalence of long-term outcomes, a judgement is required as to whether the benefits associated with earlier recovery are worth this extra cost. The long-term follow-up of the RCT cohorts would be very useful further research and ideally these data should be incorporated into a wider IPD meta-analysis. Data on the long-term complications of surgery such as incisional hernias and differences in outcomes such as persisting pain would also be valuable. Once available, further data on both costs and utilities should be included in an updated model. At this point, further consideration should then be given as to whether additional data should be collected within ongoing trials. Few data were available to assess the relative merits of HALS. Ideally, there should be more data from methodologically sound RCTs. Further research is needed on whether the balance of advantages and disadvantages of laparoscopic surgery varies within subgroups based on the different stages and locations of disease. Research relating to the effect of experience on performance is also required.

Effects of polyethylene glycol and hydroxyethyl starch in University of Wisconsin preservation solution on human red blood cell aggregation and viscosity

University of Wisconsin (UW) preservation solution is considered an effective flush and cold storage liquid. However, recent studies have provided evidence of the hyperaggregating effect on human red blood cells (RBC) of hydroxyethyl starch (HES), one of the components of the UW solution. In contrast, preservation solutions containing polyethylene glycol (PEG) have been found to be effective for organ preservation. The aim of this study was to compare the effects of HES (50 g/L); PEG 20 kDa (50 and 30 g/L), and PEG35 kDa (1.05 g/L) added to UW on the rheologic parameters of human RBC at 4 degrees C. Sedimentation rate was measured by the Westergren procedure and blood viscosity evaluated at high shear rates using a cone/plate viscometer. Alterations in RBC morphology and aggregation were evaluated by light microscopy. RBC sedimentation and viscosity were not affected by the inversion of Na+ and K+ concentrations in UW, but were increased by HES. PEGs appeared to reduce RBC deformability with concomitant inhibition of RBC aggregation. These results were consistent with reduced viscosity for PEG-containing solutions. In conclusion, the use of PEG did not change the physiologic function of human RBCs and thus may be an alternative to HES in UW liquids.

Rosiglitazone up-regulates lipoprotein lipase, hormone-sensitive lipase and uncoupling protein-1, and down-regulates insulin-induced fatty acid synthase gene expression in brown adipocytes of Wistar rats

AIMS/HYPOTHESIS

Although thiazolidinediones are now widely used to treat type 2 diabetes, their mechanism of action remains largely unknown. They are agonists for the transcription factor PPARgamma, and in addition to their insulin-sensitising effects, they can promote adipogenesis and control gene expression in adipose tissues. We have explored the effect of rosiglitazone on insulin-mediated induction of pivotal genes involved in lipid metabolism and thermogenesis in brown fat. The genes studied were: (1) lipoprotein lipase (lpl), which is involved in lipid uptake; (2) hormone-sensitive lipase (hsl), which mobilises fatty acids from stored triglycerides; (3) fatty acid synthase (fas), which regulates de novo lipogenesis; and (4) the uncoupling proteins (ucp) 1 and 3, which control thermogenesis.

METHODS

We used fetal rat primary brown adipocytes cultured with insulin, rosiglitazone or both combined. Then, we studied gene expression by northern and western blotting, as well as 'run-on' and gel-shift assays to identify binding of potential transcription factors to the fas promoter.

RESULTS

Exposure to rosiglitazone for 24 h induced ucp-1, lpl and hsl gene expression and when rosiglitazone was combined with insulin a synergistic effect on lpl and ucp-3 mRNA expression was produced. These effects were consistent with increased LPL and HSL activities as well as respiration rates, mainly in response to exogenous palmitate. In contrast, treatment with rosiglitazone did not alter FAS mRNA basal levels but prevented the induction elicited by insulin in a time- and dose-dependent manner. Correspondingly diminished FAS protein levels and activity, as well as cellular lipid content, were observed, indicating an antilipogenic action of rosiglitazone in brown adipocytes. Furthermore, rosiglitazone impaired insulin increase in the FAS transcription rate by antagonising insulin-induced binding of upstream stimulatory factors to the E-box consensus sequence in the FAS promoter and insulin-induced binding of activating protein-1.

CONCLUSIONS/INTERPRETATION

Rosiglitazone prevents insulin-induced up-regulation of the main lipogenic enzyme but increases the expression of those enzymes involved in lipid uptake and mobilisation, favouring fatty acid utilisation through uncoupled respiration.

Rosiglitazone ameliorates insulin resistance in brown adipocytes of Wistar rats by impairing TNF-alpha induction of p38 and p42/p44 mitogen-activated protein kinases

AIMS/HYPOTHESIS

TNF-alpha caused insulin resistance on glucose uptake and on insulin signalling in fetal brown adipocytes. Since treatment with TNF-alpha activates stress kinases, including c-jun NH2 terminal kinase (JNK), and p42/p44 and p38 mitogen-activated protein kinases (MAPK), we explored the contribution of these pathways to insulin resistance by TNF-alpha. Rosiglitazone is used to treat Type 2 diabetes as it improves insulin sensitivity in vivo. However, its ability to ameliorate TNF-alpha-induced insulin resistance in brown adipocytes remains to be explored.

METHODS

We used fetal rat primary brown adipocytes cultured with TNF-alpha, with or without stress kinase inhibitors or rosiglitazone, and further stimulated with insulin. Then, we measured glucose uptake and GLUT4 translocation. To determine the insulin signalling cascade, we submitted cells to lysis, immunoprecipitation and immunoblotting.

RESULTS

Exposure to TNF-alpha for 24 h impairs insulin stimulation of the phosphatidylinositol (PI) 3-kinase activity associated with IRS-2 and Akt activity. Pretreatment with PD98059 or PD169316, which inhibit p42/p44MAPK and p38MAPK respectively, restored insulin signalling and insulin-induced glucose uptake in the presence of TNF-alpha. However, in the presence of SP600125, an inhibitor of JNK, TNF-alpha still produced insulin resistance. Rosiglitazone ameliorated insulin resistance by TNF-alpha in brown adipocytes, restoring completely insulin-stimulated glucose uptake and insulin-induced GLUT4 translocation to plasma membrane in parallel to the insulin signalling cascade IRS-2/PI 3-kinase/Akt.

CONCLUSIONS/INTERPRETATION

Rosiglitazone treatment impaired TNF-alpha activation of p38 and p42/p44MAPK, restoring insulin signalling and leading to normalisation of glucose uptake.

Systematic review of the effectiveness and cost-effectiveness, and economic evaluation, of myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction

OBJECTIVES

To assess the effectiveness and cost-effectiveness of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction (MI).

DATA SOURCES

Major electronic databases.

REVIEW METHODS

Two reviewers independently extracted data and assessed study quality. A decision tree model was used to model the diagnosis decision and a Markov model was developed for the management of patients with suspected coronary artery disease. Costs for the treatments and interventions within strategies were derived from the literature and expressed in 2001-02 pounds sterling. Quality-adjusted life-year (QALY) weights for the different Markov model states were also obtained from the literature.

RESULTS

Twenty-one diagnostic and 46 prognostic studies were included, plus two studies comparing SPECT with electrocardiography (ECG)-gated SPECT and one study comparing SPECT with attenuation-corrected SPECT. The diagnostic values of SPECT were generally higher than those of stress ECG, indicating that SPECT provided a better diagnostic performance. SPECT also provided higher positive and lower negative likelihood ratios than stress ECG but heterogeneity was evident among studies. The subgroup of studies including patients with previous MI tended to report a better diagnostic performance for SPECT than stress ECG, but there were too few studies to assess this reliably. The extent and size of the perfusion defect, and whether reversible or fixed, were important factors in predicting future cardiac events such as cardiac death or non-fatal MI. SPECT may be able to identify lower risk patients for whom coronary angiography (CA) might be avoided. Normal SPECT scans were associated with a benign prognosis and the option of medical rather than invasive management. Four studies of patients post-MI reported SPECT to be valuable in stratifying patients into at-risk groups for further cardiac events. The two studies comparing SPECT with ECG-gated SPECT, one diagnostic and the other prognostic, found in favour of gated SPECT. The study comparing SPECT with attenuation-corrected SPECT reported the latter to be more accurate. The systematic review of economic evaluations indicated that strategies involving SPECT were likely either to be dominant or to produce more QALYs at an acceptable cost. There was less agreement about which of the strategies involving SPECT was optimal. The model suggested that, for low prevalence, the incremental cost per unit of output (true positives diagnosed, accurate diagnosis, QALY) for the move from stress ECG-SPECT-CA and from stress ECG-CA to SPECT-CA might be considered worthwhile. Even after allowing for different values for sensitivity or specificity, the least costly and least effective strategy was stress ECG-SPECT-CA. The sensitivity analysis suggested that the cost-effectiveness of SPECT-CA improved if it was assumed that SPECT results allowed for the adoption of a management strategy without recourse to CA. As the time horizon reduced, the incremental cost per QALY increased (as the cost of initial diagnosis and treatment were not offset by survival and quality of life gains).

CONCLUSIONS

There was a considerable variability in terms of measurement of outcomes, management, setting and patient characteristics, however the direction of evidence tended to favour SPECT in terms of test sensitivity, although these conclusions are based on a relatively small number of diagnostic studies. SPECT, in a variety of settings and patient populations, provided valuable independent and incremental prognostic information to that provided by stress ECG and/or CA that helped to risk-stratify patients and influence the way in which their condition was managed. However, all of the prognostic studies were observational studies and may be biased by unknown confounding factors. Although the ECG-gated and attenuation-corrected SPECT findings seem promising, it is difficult to draw conclusions from so few studies. Further research is needed on the effectiveness and cost-effectiveness, diagnostically and prognostically, of (a) gated and attenuation-corrected SPECT compared with standard SPECT, (b) standard SPECT compared with stress echocardiography and (c) the uncertainty surrounding the results presented in the cost-effectiveness analysis.

Rosiglitazone produces insulin sensitisation by increasing expression of the insulin receptor and its tyrosine kinase activity in brown adipocytes

AIMS/HYPOTHESIS

Rosiglitazone is used to treat Type 2 diabetes because it improves insulin sensitivity. However, the specific molecular mechanism by which this compound acts has not yet been explained.

METHODS

We used fetal rat primary brown adipocytes cultured for 24 h with or without 10 micro mol/l rosiglitazone and further stimulated for 5 min with 10 nmol/l insulin. Next we measured glucose uptake and GLUT4 translocation and submitted the cells to lysis, immunoprecipitation and immunoblotting in order to measure the insulin signalling cascade.

RESULTS

Rosiglitazone noticeably activated basal glucose uptake in a manner dependent on p38-mitogen-activated protein kinase. Rosiglitazone also produced a 40% increase in insulin-stimulated glucose uptake as a result of increased GLUT4 translocation to the plasma membrane. This happened without changes in the expression of GLUT4 at the mRNA or protein level. This effect correlated with the potentiation by rosiglitazone of insulin-stimulated Tyr phosphorylation of insulin receptor substrate-1 and to a greater extent of insulin receptor substrate-2. It also correlated with the subsequent activation of phosphatidylinositol 3-kinase and Akt, without changes in protein kinase Czeta activity. Rosiglitazone treatment increased insulin receptor expression and insulin-stimulated Tyr phosphorylation of insulin receptor beta-chain, but decreased insulin-stimulated Ser phosphorylation. It also potentiated insulin-induced Tyr phosphorylation of insulin receptor beta-chain and protein tyrosine phosphatase 1B in co-immunoprecipitates and impaired insulin activation of protein tyrosine phosphatase 1B activity.

CONCLUSIONS/INTERPRETATION

At the insulin receptor level, rosiglitazone-induced improvements of insulin sensitivity result from two convergent mechanisms: increased insulin receptor expression and insulin receptor activation.

Isolation and identification of an esterase from a Mexican strain of Boophilus microplus (Acari: Ixodidae)

A strain of Mexican Boophilus microplus (Cz) collected near Coatzacoalcos, Veracruz, Mexico, exhibits a moderate, but significant, level of permethrin resistance. Unlike other highly permethrin resistant strains, the Cz strain does not have a mutation within the sodium channel gene that results in target-site insensitivity. However, the Cz strain possesses a substantial increase in general and permethrin esterase activity relative to highly permethrin resistant and control strains suggesting the involvement of a metabolic esterase(s) in the expression of permethrin resistance. We report the isolation of a 62.8 kDa protein from Cz strain larvae that we think is the esterase previously reported as Cz EST9. In addition, internal amino acid sequence data obtained from the 62.8 kDa protein suggest that it is the gene product of a previously reported B. microplus carboxylesterase cDNA. We propose that the 62.8 kDa protein (Cz EST9) has permethrin hydrolytic activity and as a result plays an important role in Cz strain resistance to permethrin.

Allele frequency and gene expression of a putative carboxylesterase-encoding gene in a pyrethroid resistant strain of the tick Boophilus microplus

We utilized RNA Northern blot analysis and ribonuclease protection assays (RPA) to study the mRNA expression level of a putative carboxylesterase-encoding gene from several strains of Boophilus microplus (Canestrini). Both the Northern analysis and RPAs indicated that an esterase transcript was more abundant in the pyrethroid resistant strain, Coatzacoalcos (Cz), compared to a susceptible control strain and a resistant strain whose pyrethroid resistance is mediated through a target site insensitivity mechanism. A PCR-based assay was designed to identify the presence of a previously reported point mutation in this B. microplus esterase gene. The reported G-->A substitution at nucleotide 1120 creates an EcoR I site in the mutant allele which can be detected by EcoR I digestion of the amplification products. The PCR assays showed that the frequency of the mutant allele was highest in the Cz-resistant strain, which has been shown to have an esterase-mediated resistance mechanism. The PCR assay can be performed either on individual tick larvae or hemolymph from adults.