Oxidative stress and its haemodynamic consequences in chronic kidney disease

Chronic kidney disease (CKD) is associated with increased cardiovascular risk in comparison with the general population. This can be observed even in the early stages of CKD, and rises in proportion to the degree of renal impairment. Not only is cardiovascular disease (CVD) more prevalent in CKD, but its nature differs too, with an excess of morbidity and mortality associated with congestive cardiac failure, arrhythmia and sudden death, as well as the accelerated atherosclerosis which is also observed. Conventional cardiovascular risk factors such as hypertension, dyslipidaemia, obesity, glycaemia and smoking, are highly prevalent amongst patients with CKD, although in many of these examples the interaction between risk factor and disease differs from that which exists in normal renal function. Nevertheless, the extent of CVD cannot be fully explained by these conventional risk factors, and non-conventional factors specific to CKD are now recognised to contribute to the burden of CVD. Oxidative stress is a state characterised by excessive production of reactive oxygen species (ROS) and other radical species, a reduction in the capacity of antioxidant systems, and disturbance in normal redox homeostasis with depletion of protective vascular signalling molecules such as nitric oxide (NO). This results in oxidative damage to macromolecules such as lipids, proteins and DNA which can alter their functionality. Moreover, many enzymes are sensitive to redox regulation such that oxidative modification to cysteine thiol groups results in activation of signalling cascades which result in adverse cardiovascular effects such as vascular and endothelial dysfunction. Endothelial dysfunction and oxidative stress are present in association with many conventional cardiovascular risk factors, and can be observed even prior to the development of overt, clinical, vascular pathology, suggesting that these phenomena represent the earliest stages of CVD. In the presence of CKD, there is increased ROS production due to upregulated NADPH oxidase (NOX), increase in a circulating asymmetric dimethylarginine (ADMA), uncoupling of endothelial nitric oxide synthase (eNOS) as well as other mechanisms. There is also depletion in exogenous antioxidants such as ascorbic acid and tocopherol, and a reduction in activity of endogenous antioxidant systems regulated by the master gene regulator Nrf-2. In previous studies, circulating markers of oxidative stress have been shown to be increased in CKD, together with a reduction in endothelial function in a stepwise fashion relating to the severity of renal impairment. Not only is CVD linked to oxidative stress, but the progression of CKD itself is also in part dependent on redox sensitive mechanisms. For example, administration of the ROS scavenger tempol attenuates renal injury and reduces renal fibrosis seen on biopsy in a mouse model of CKD, whilst conversely, supplementation with the NOS inhibitor L-NAME causes proteinuria and renal impairment. Previous human studies examining the effect of antioxidant administration on vascular and renal function have been conflicting however. The work contained in this thesis therefore examines the effect of antioxidant administration on vascular and endothelial function in CKD. Firstly, 30 patients with CKD stages 3 – 5, and 20 matched hypertensive controls were recruited. Participants with CKD had lower ascorbic acid, higher TAP and ADMA, together with higher augmentation index and pulse wave velocity. There was no difference in baseline flow mediated dilatation (FMD) between groups. Intravenous ascorbic acid increased TAP and O2-, and reduced central BP and augmentation index in both groups, and lowered ADMA in the CKD group only. No effect on FMD was observed. The effects of ascorbic acid on kidney function was then investigated, however this was hindered by the inherent drawbacks of existing methods of non-invasively measuring kidney function. Arterial spin labelling MRI is an emerging imaging technique which allows measurement of renal perfusion without administration of an exogenous contrast agent. The technique relies upon application of an inversion pulse to blood within the vasculature proximal to the kidneys, which magnetically labels protons allowing measurement upon transit to the kidney. At the outset of this project local experience using ASL MRI was limited and there ensued a prolonged pre-clinical phase of testing with the aim of optimising imaging strategy. A study was then designed to investigate the repeatability of ASL MRI in a group of 12 healthy volunteers with normal renal function. The measured T1 longitudinal relaxation times and ASL MRI perfusion values were in keeping with those found in the literature; T1 time was 1376 ms in the cortex and 1491 ms in the whole kidney ROI, whilst perfusion was 321 mL/min/100g in the cortex, and 228 mL/min/100g in the whole kidney ROI. There was good reproducibility demonstrated on Bland Altman analysis, with a CVws was 9.2% for cortical perfusion and 7.1% for whole kidney perfusion. Subsequently, in a study of 17 patients with CKD and 24 healthy volunteers, the effects of ascorbic acid on renal perfusion was investigated. Although no change in renal perfusion was found following ascorbic acid, it was found that ASL MRI demonstrated significant differences between those with normal renal function and participants with CKD stages 3 – 5, with increased cortical and whole kidney T1, and reduced cortical and whole kidney perfusion. Interestingly, absolute perfusion showed a weak but significant correlation with progression of kidney disease over the preceding year. Ascorbic acid was therefore shown to have a significant effect on vascular biology both in CKD and in those with normal renal function, and to reduce ADMA only in patients with CKD. ASL MRI has shown promise as a non-invasive investigation of renal function and as a biomarker to identify individuals at high risk of progressive renal impairment.

Effect of remote ischaemic preconditioning in cardiac dysfunction and end-organ injury following cardiac surgery with cardiopulmonary bypass in children: A translational approach investigating clinical outcome and myocardial molecular biology

Congenital heart disease (CHD) is the most common birth defect, causing an important rate of morbidity and mortality. Treatment of CHD requires surgical correction in a significant percentage of cases which exposes patients to cardiac and end organ injury. Cardiac surgical procedures often require the utilisation of cardiopulmonary bypass (CPB), a system that replaces heart and lungs function by diverting circulation into an external circuit. The use of CPB can initiate potent inflammatory responses, in addition a proportion of procedures require a period of aortic cross clamp during which the heart is rendered ischaemic and is exposed to injury. High O2 concentrations are used during cardiac procedures and when circulation is re-established to the heart which had adjusted metabolically to ischaemia, further injury is caused in a process known as ischaemic reperfusion injury (IRI). Several strategies are in place in order to protect the heart during surgery, however injury is still caused, having detrimental effects in patients at short and long term. Remote ischaemic preconditioning (RIPC) is a technique proposed as a potential cardioprotective measure. It consists of exposing a remote tissue bed to brief episodes of ischaemia prior to surgery in order to activate protective pathways that would act during CPB, ischaemia and reperfusion. This study aimed to assess RIPC in paediatric patients requiring CHD surgical correction with a translational approach, integrating clinical outcome, marker analysis, cardiac function parameters and molecular mechanisms within the cardiac tissue. A prospective, single blinded, randomized, controlled trial was conducted applying a RIPC protocol to randomised patients through episodes of limb ischaemia on the day before surgery which was repeated right before the surgery started, after anaesthesia induction. Blood samples were obtained before surgery and at three post-operative time points from venous lines, additional pre and post-bypass blood samples were obtained from the right atrium. Myocardial tissue was resected during the ischaemic period of surgery. Echocardiographic images were obtained before the surgery started after anaesthetic induction and the day after surgery, images were stored for later off line analysis. PICU surveillance data was collected including ventilation parameters, inotrope use, standard laboratory analysis and six hourly blood gas analysis. Pre and post-operative quantitation of markers in blood specimens included cardiac troponin I (cTnI) and B-type natriuretic peptide (BNP), inflammatory mediators including interleukins IL-6, IL-8, IL-10, tumour necrosis factor (TNF-α), and the adhesion molecules ICAM-1 and VCAM-1; the renal marker Cystatin C and the cardiovascular markers asymmetric dymethylarginine (ADMA) and symmetric dymethylarginine (SDMA). Nitric oxide (NO) metabolites and cyclic guanosine monophosphate (cGMP) were measured before and after bypass. Myocardial tissue was processed at baseline and after incubation at hyperoxic concentration during four hours in order to mimic surgical conditions. Expression of genes involved in IRI and RIPC pathways was analysed including heat shock proteins (HSPs), toll like receptors (TLRs), transcription factors nuclear factor κ-B (NF- κ-B) and hypoxia inducible factor 1 (HIF-1). The participation of hydrogen sulfide enzymatic genes, apelin and its receptor were explored. There was no significant difference according to group allocation in any of the echocardiographic parameters. There was a tendency for higher cTnI values and inotropic score in control patients post-operatively, however this was not statistically significant. BNP presented no significant difference according to group allocation. Inflammatory parameters tended to be higher in the control group, however only TNF- α was significantly higher. There was no difference in levels of Cystatin C, NO metabolites, cGMP, ADMA or SDMA. RIPC patients required shorter PICU stay, all other clinical and laboratory analysis presented no difference related to the intervention. Gene expression analysis revealed interesting patterns before and after incubation. HSP-60 presented a lower expression at baseline in tissue corresponding to RIPC patients, no other differences were found. This study provided with valuable descriptive information on previously known and newly explored parameters in the study population. Demographic characteristics and the presence of cyanosis before surgery influenced patterns of activity in several parameters, numerous indicators were linked to the degree of injury suffered by the myocardium. RIPC did not reduce markers of cardiac injury or improved echocardiographic parameters and it did not have an effect on end organ function; some effects were seen in inflammatory responses and gene expression analysis. Nevertheless, an important clinical outcome indicator, PICU length of stay was reduced suggesting benefit from the intervention. Larger studies with more statistical power could determine if the tendency of lower injury and inflammatory markers linked to RIPC is real. The present results mostly support findings of larger multicentre trials which have reported no cardiac benefit from RIPC in paediatric cardiac surgery.

The Effectiveness of Community-Based Nutrition Education on the Nutrition Status of Under-five Children in Developing Countries. A Systematic Review

Aim This systematic review aimed at examining the best available evidence on the effectiveness of community-based nutrition education in improving the nutrition status of under five children in developing countries. Methods A systematic search of the literature was conducted utilising the following data bases: Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Medline, and Web of Knowledge. 9 studies were identified for the critical appraisal process. The Joanna Briggs Institute (JBI) critical appraisal check-list for experimental studies was utilised and two reviewers conducted the appraisal process independently. 7 studies were included for this review and data was extracted using the JBI data extraction form for experimental studies. The extracted data was heterogeneous as such narrative synthesis was conducted. Results The nutritional status of children in all studies improved and this was evidenced by increases in weight, height, mid upper arm circumference and reduced morbidity. Key messages about education were age at introduction of complementary foods, nutrition value on different types of feeds found locally and frequency of feeding the children. However, there were varied Results regarding the effects of the intervention on the nutrition status of children. This was attributed by differences in implementers’ characteristics, different intervention strategy and intensity, difference in age of the children at enrolment, pre-existing children’s growth and nutritional status and follow-up periods. In addition to home visiting, conducting group meetings of care givers and community leaders, providing education twice a week and use of cooking demonstrations have shown that they produce highly significant findings. Conclusion The evidence from the identified studies suggests that community- based nutrition education improves the nutrition status of under-five children in developing countries.

Aerobic endurance in HIV-positive young adults and HIV-negative controls in Malawi

Background Aerobic endurance is an important aspect of physical fitness that enables individuals living with HIV to endure in the work place as well as in agricultural operations in order to earn a living and improve their quality of life. However, despite high HIV prevalence rates, the aerobic endurance status of young Malawians living with HIV remains unknown. The objective of this study was to determine the difference in VO2max between HIV-negative and HIV-positive individuals in Blantyre, Malawi. Methods Fifty five participants (17 males and 38 females) who have HIV and were not taking antiretroviral medication and 78 HIV-negative participants (45 males and 33 females) performed the Rockport submaximal treadmill exercise test. Measures of body weight, post-exercise heart rate and time to walk one mile were obtained and used to predict VO2max. Comparisons between groups were adjusted for age differences using analysis of covariance (ANCOVA). Results VO2max was significantly lower in HIV-positive subjects [31.1, 28.7 - 33.5mL.kg-1.min-1(mean, 95% CI)] compared with HIV-negative subjects [56.2, 54.3 - 58.1mL.kg-1.min-1]. Conclusion Aerobic endurance was markedly reduced in HIV-positive participants compared with HIV-negative participants. Findings of the current study implicate factors associated with the HIV infection as contributors to a decreased aerobic endurance in people living with HIV.

The Comparison of Under-Five-Children’s Nutrition Status Among Ethnic Groups in North of Iran, 1998 - 2013; Results of a Three Stages Cross-Sectional Study

Background: Despite improvements in child health, malnutrition still remains one of the main public health challenges in Iran. Objectives: The aim of this study was to compare under nutrition among under-five children with regard to ethnicity in rural area in north Iran. Patients and Methods: In three cross-sectional studies 7575 subjects in three time-periods including 2339 children in 1998, 2749 in 2004, and 2487 in 2013, were evaluated. All under-five-children in 20 out of 118 villages were chosen by random sampling and assessed. Under nutrition was defined as underweight, stunting and wasting lower than -2 SD (Z < -2 SD). Results: Generally, stunting was declined 17.1% and underweight and wasting were increased 0.9% and 1%, respectively during 15 years (1998 - 2013). Underweight increased 0.5% in Fars-natives and 3.2% in Turkmans and it was decreased 0.9% in Sistanis. Statistical difference in Turkman children among the three stages of the study was significant (P = 0.001). Stunting has decreased 28.7% in Fars-natives and 35.1% in Sistanis, it was increased 9.3% in Turkman group. Statistical differences among three stages in inter-ethnic groups were significant (P = 0.001 for all). Compared the group with good economic status, the odds ratio was 1.831 in poor economic group (P = 0.001). The risk of under nutrition in Sistanis was 1.754 times more than in Fars-natives (P = 0.001). Conclusions: Under nutrition remains one of the main health problems in under-five-year children in north Iran being more common in Sistani children. Stunting in Sistani children deeply decreased while in Turkman children slightly increased during the 15-year period study. Poor economic status is a risk factor for under nutrition in this area.

A Randomized Double-Blind Placebo-Controlled Trial of Lactobacillus reuteri for Chronic Functional Abdominal Pain in Children

Background: Functional abdominal pain (FAP) is one of the most common diseases, and large percentages of children suffer from it. Objectives: The purpose of the study was to evaluate the effect of Lactobacillus reuteri in treatment of children with functional abdominal pain. Patients and Methods: This study was a randomized double-blind placebo-controlled trial. Children aged 4 to 16 years with chronic functional abdominal pain (based on Rome III criteria) were enrolled in the study. They were randomly divided into two groups, one receiving probiotic and the other placebo. Results: Forty children received probiotic and forty others placebo. There were no significant differences in age, weight, sex, location of pain, associated symptoms, frequency and intensity of pain between the groups. The severity and frequency of abdominal pain in the first month compared to baseline was significantly less and at the end of the second month, there was no significant difference between both groups compared to the end of the first month. Conclusions: This study showed that the severity of pain was significantly reduced in both groups. There was no significant difference in pain scores between them. The effect of probiotic and placebo can probably be attributed to psychological effect of the drugs.

Clinical efficacy of paclitaxel in the treatment of mid-stage and advanced malignant gastric cancer, and effect of nursing interventions

Purpose: To investigate the clinical efficacy of paclitaxel combined with additional chemotherapy for mid-stage and advanced malignant tumors, and the benefits afforded by scientific nursing. Methods: Patients with mid-stage and advanced gastric cancer were randomly divided into test and control groups. Control group was given intravenous chemotherapy (400 mg/m2 fluorouracil and 2500 mg/m2 cisplatin) and nursed conventionally, while the test group was additionally treated with 80 mg/m2 paclitaxel and underwent special scientific nursing. Clinical effects and changes in the rates of apoptosis and cell proliferation were recorded. The effect of applying scientific nursing on therapeutic outcomes was also evaluated. Results: The overall rate of treatment effectiveness, clinical control rate, mean apoptosis and proliferation rates in the test group were 56.40, 92.30, (7.10 ± 3.17 and 28.70 ± 3.22 %, respectively, while, in the control group, the values were 38.50, 64.10, 25.40 ± 2.67 and 32.60 ± 2.93 %, respectively. The differences were all statistically significant (p < 0.05). In terms of nursing efficacy, the test group had a lower pain score and higher quality-of-life scores (Karnofsky performance status score) than control group. There was no significant difference in the incidence of adverse reactions between the two groups (p > 0.05). Conclusion: Paclitaxel has a significant effect when used to treat mid-stage and advanced gastric cancer. Moreover, additional nursing not only enhances the therapeutic effect but also improves prognosis and quality-of-life.

Therapeutic efficacy of alternative primaquine regimens to standard treatment in preventing relapses by Plasmodium vivax : A systematic review and meta-analysis

Objective: To compare efficacy and safety of primaquine regimens currently used to prevent relapses by Plasmodium vivax. Methods: A systematic review was carried out to identify clinical trials evaluating efficacy and safety to prevent malaria recurrences by P. vivax of primaquine regimen 0.5 mg/kg/day for 7 or 14 days compared to standard regimen of 0.25 mg/kg/day for 14 days. Efficacy of primaquine according to cumulative incidence of recurrences after 28 days was determined. The overall relative risk with fixed-effects meta-analysis was estimated. Results: For the regimen 0.5 mg/kg/day/7 days were identified 7 studies, which showed an incidence of recurrence between 0% and 20% with follow-up 60-210 days; only 4 studies comparing with the standard regimen 0.25 mg/kg/day/14 days and no difference in recurrences between both regimens (RR= 0.977, 95% CI= 0.670 to 1.423) were found. 3 clinical trials using regimen 0.5 mg/kg/day/14 days with an incidence of recurrences between 1.8% and 18.0% during 330-365 days were identified; only one study comparing with the standard regimen (RR= 0.846, 95% CI= 0.484 to 1.477). High risk of bias and differences in handling of included studies were found. Conclusion: Available evidence is insufficient to determine whether currently PQ regimens used as alternative rather than standard treatment have better efficacy and safety in preventing relapse of P. vivax. Clinical trials are required to guide changes in treatment regimen of malaria vivax.

Therapeutic efficacy of alternative primaquine regimens to standard treatment in preventing relapses by Plasmodium vivax: A systematic review and meta-analysis

Objective: To compare efficacy and safety of primaquine regimens currently used to prevent relapses by Plasmodium vivax. Methods: A systematic review was carried out to identify clinical trials evaluating efficacy and safety to prevent malaria recurrences by P. vivax of primaquine regimen 0.5 mg/kg/day for 7 or 14 days compared to standard regimen of 0.25 mg/kg/day for 14 days. Efficacy of primaquine according to cumulative incidence of recurrences after 28 days was determined. The overall relative risk with fixed-effects meta-analysis was estimated. Results: For the regimen 0.5 mg/kg/day/7 days were identified 7 studies, which showed an incidence of recurrence between 0% and 20% with follow-up 60-210 days; only 4 studies comparing with the standard regimen 0.25 mg/kg/day/14 days and no difference in recurrences between both regimens (RR= 0.977, 95% CI= 0.670 to 1.423) were found. 3 clinical trials using regimen 0.5 mg/kg/day/14 days with an incidence of recurrences between 1.8% and 18.0% during 330-365 days were identified; only one study comparing with the standard regimen (RR= 0.846, 95% CI= 0.484 to 1.477). High risk of bias and differences in handling of included studies were found. Conclusion: Available evidence is insufficient to determine whether currently PQ regimens used as alternative rather than standard treatment have better efficacy and safety in preventing relapse of P. vivax. Clinical trials are required to guide changes in treatment regimen of malaria vivax.

Alcohol use disorders and psychiatric diseases in Colombia

Background: An accurate understanding of co-occurrence and comorbidity of alcohol use disorders (AUD) in Colombia is crucial for public health. Objective: A secondary analysis was conducted, using a 2003/2004 government´s population database to determine the lifetime associations between AUD and other mental and addictive disorders in people of Colombia aged 18-65 years. Methods: Several statistical analysis were performed: testing prevalence difference in mental disorders by whether the individual had an AUD; a stratified analysis by gender and logistic regression analyses accounting for differences in demographic, socio-economic, behavioral and self-reported health status variables. Results: People with AUD comprised 9% of the population, of which 88% were males and on average 37 years old. They were more likely to be males, be working, and be current smokers; and less likely to be at home or retired. The population with AUD had greater chance to comply with criteria for all disorders but minor depressive disorder, post-traumatic stress disorder, nicotine dependence, and oppositional defiant disorder. Conclusion: This study demonstrates a high prevalence of mental disorders in the adult population with AUD in Colombia. The findings highlight the importance of comorbidity as a sign of disease severity and impact on public health and supports the need for training of more professionals and developing appropriate interventions and services.

USING MOSSES TO ASSESS CONDITIONS IN NORTHERN WHITE CEDAR SWAMPS

Northern white cedar (Thuja occidentalis L.) (NWC) swamps are valuable both commercially and ecologically. Unfortunately, many NWC swamps are degraded and information about them is not abundant. Especially there have been no definitive studies about mosses in northern white cedar swamps and how they react to disturbances. Mosses are sensitive to changes in their environment and thus they could be used to assess ecosystem conditions of NWC swamps. The objective of this study was to determine if mosses could be used to asses conditions in NWC swamps and if there are differences between moss communities in disturbed and undisturbed sites. Seventeen sample plots were taken from 12 disturbed and undisturbed sites around upper Michigan and northern Minnesota in the summer of 2012. All mosses occurring on the plots were identified and several associated environmental parameters were measured. The main environmental conditions affecting moss communities were identified with non-metric multidimensional scaling (NMS). Multiple response permutation procedures (MRPP) were run to ascertain if there were significant differences in community composition between disturbances. Indicator species analysis was then done to identify species that are related to different types of disturbances. A one-way ANOVA was used to check for significant differences between species richness and moss cover of undisturbed and disturbed sites. Over all sixty-two moss species were identified. The results indicate that there was no significant difference in species richness or moss cover between disturbed and undisturbed sites. However, moss community composition was affected by disturbance and strongly divided by a wetness gradient. Dicranum fuscescens was found to indicate undisturbed conditions. Calliergon cordifolium and Climacium dendroides indicated disturbed sites with wet conditions. Brotherella recurvans and Eurhynchium pulchellum indicated swamps with other disturbances.

Prevalence and audiological features in carriers of GJB2 mutations, c.35delG and c.101T>C (p.M34T), in a UK population study

OBJECTIVES: To determine the carrier rate of the GJB2 mutation c.35delG and c.101T>C in a UK population study; to determine whether carriers of the mutation had worse hearing or otoacoustic emissions compared to non-carriers. DESIGN: Prospective cohort study. SETTING: University of Bristol, UK. PARTICIPANTS: Children in the Avon Longitudinal Study of Parents and Children. 9202 were successfully genotyped for the c.35delG mutation and c.101>T and classified as either carriers or non-carriers. OUTCOME MEASURES: Hearing thresholds at age 7, 9 and 11 years and otoacoustic emissions at age 9 and 11. RESULTS: The carrier frequency of the c.35delG mutation was 1.36% (95% CI 1.13 to 1.62) and c.101T>C was 2.69% (95% CI 2.37 to 3.05). Carriers of c.35delG and c.101T>C had worse hearing than non-carriers at the extra-high frequency of 16 kHz. The mean difference in hearing at age 7 for the c.35delG mutation was 8.53 dB (95% CI 2.99, 14.07) and 12.57 dB at age 9 (95% CI 8.10, 17.04). The mean difference for c.101T>C at age 7 was 3.25 dB (95% CI -0.25 to 6.75) and 7.61 dB (95% CI 4.26 to 10.96) at age 9. Otoacoustic emissions were smaller in the c.35delG mutation carrier group: at 4 kHz the mean difference was -4.95 dB (95% CI -6.70 to -3.21) at age 9 and -3.94 dB (95% CI -5.78 to -2.10) at age 11. There was weak evidence for differences in otoacoustic emissions amplitude for c.101T>C carriers. CONCLUSION: Carriers of the c.35delG mutation and c.101T>C have worse extra-high-frequency hearing than non-carriers. This may be a predictor for changes in lower-frequency hearing in adulthood. The milder effects observed in carriers of c.101T>C are in keeping with its classification as a mutation causing mild/moderate hearing loss in homozygosity or compound heterozygosity.

Prevalence of Escherichia coli Virulence Genes in Patients with Diarrhea and a Subpopulation of Healthy Volunteers in Madrid, Spain

Etiological diagnosis of diarrheal diseases may be complicated by their multi-factorial nature. In addition, Escherichia coli strains present in the gut can occasionally harbor VGs without causing disease, which complicates the assessment of their clinical significance in particular. The aim of this study was to detect and quantify nine VGs (stx1, stx2, eae, aggR, ehxA, invA, est and elt) typically present in five E. coli enteric pathotypes (EHEC, ETEC, EPEC, EAEC and EIEC) in fecal samples collected from 49 patients with acute diarrhea and 32 healthy controls from Madrid, Spain. In addition, the presence of four serotype-related genes (wzxO104 and fliCH4, rbfO157 and fliCH7) was also determined. Presence of target genes was assessed using a quantitative real-time PCR assay previously developed, and the association of presence and burden of VGs with clinical disease and/or other risk factors was explored. Prevalence of ehxA (typically associated with STEC and EPEC), invA (EIEC) and the rbfO157+fliCH7 (STEC and/or STEC/EAEC) combination were significantly (p<0.02) higher in the diarrheic group, while the wzxO104+fliCH4 combination was significantly (p=0.014) more prevalent in the control group. On the other hand, eae was detected in more than 90% of the individuals in both patient and control populations, and it was not associated with bfpA, suggesting the absence of typical EPEC. No significant differences in the quantitative values were detected for any VG among study groups, but the difference in the load of aggR (EAEC) and invA in the patients with respect to the controls was close to the significance, suggesting a potential role of these VGs in the clinical signs observed when they are present at high levels.

Efficiency of chitosan and their combination with bentonite as retention aids in papermaking

In a previous work (Nicu et al. 2013), the flocculation efficiency of three chitosans differing by molecular weight and charge density were evaluated for their potential use as wet end additives in papermaking. According to the promising results obtained, chitosan (single system) and its combination with bentonite (dual system) were evaluated as retention aids, and their efficiency was compared with poly(diallyl dimethyl ammonium chloride) (PDADMAC) and polyethylenimine (PEI). In single systems, chitosan was clearly more efficient in drainage rate than PDADMAC and PEI, especially those with the lowest molecular weights; however, retention is considerably lower. This drawback can be overcome by using dual systems with anionic bentonite microparticles, with the optimum ratio of polymer:bentonite being 1:4 (wt./wt.). In dual systems, the differences in retention were almost negligible, and the difference in drainage rate was even higher, together with better floc reversibility. The most efficient chitosan in single systems was Ch.MMW, while Ch.LMW was the most efficient in dual systems. The flocculation mechanism of chitosan was a combination of patch formation, charge neutralization, and partial bridge formation, and the predominant mechanism depended on the molecular weight and charge density of the chitosan.

Pelvic-Floor Rehabilitation, Part 1 : Comparison of Two Surface Electrode Placements During Stimulation of the Pelvic-Floor Musculature in Women Who Are Continent Using Bipolar Interferential Currents

Background and Purpose. Electrical stimulation of the pelvic floor is used as an adjunct in the conservative treatment of urinary incontinence. No consensus exists, however, regarding electrode placements for optimal stimulation of the pelvic-floor musculature. The purpose of this study was to compare two different bipolar electrode placements, one suggested by Laycock and Green (L2) the other by Dumoulin (D2), during electrical stimulation with interferential currents of the pelvic-floor musculature in continent women, using a two-group crossover design. Subjects. Ten continent female volunteers, ranging in age from 20 to 39 years (X̅=27.3, SD=5.6), were randomly assigned to one of two study groups. Methods. Each study group received neuromuscular electrical stimulation (NMES) of the pelvic-floor musculature using both electrode placements, the order of application being reversed for each group. Force of contraction was measured as pressure (in centimeters of water [cm H2O]) exerted on a vaginal pressure probe attached to a manometer. Data were analyzed using a two-way, mixed-model analysis of variance. Results. No difference in pressure was observed between the two electrode placements. Differences in current amplitude were observed, with the D2 electrode placement requiring less current amplitude to produce a maximum recorded pressure on the manometer. Subjective assessment by the subjects revealed a preference for the D2 electrode placement (7 of 10 subjects). Conclusion and Discussion. The lower current amplitudes required with the D2 placement to obtain recordings comparable to those obtained with the L2 technique suggest a more comfortable stimulation of the pelvic-floor muscles. The lower current amplitudes required also suggest that greater increases in pressure might be obtained with the D2 placement by increasing the current amplitude while remaining within the comfort threshold. These results will help to define treatment guidelines for a planned clinical study investigating the effects of NMES and exercise in the treatment of urinary stress incontinence in women postpartum.