Novel water treatment system in a low-resource community.

This paper evaluates the performance of a low-cost technology in rural Benin (West Africa) that locally produces chlorine (sodium hypochlorite) and then injects it into the community water tanks. Thirty-one water tanks were selected in cooperation with local authorities to receive electro-chlorinator devices (WATA™). Water samples were tested at two points: before chlorination and at the most distant terminal after chlorination. Residual chlorine control tests and microbiology control tests were performed. Water samples that tested positive for the presence of microorganisms were analyzed at a laboratory when possible. The water provided to the community was not always chlorinated, and over half of the tanks lacked access to chlorine powder. Among the sites using the technology, 30% (9/31) of them had structural problems that prevented the existing system from performing adequately. Furthermore, 60% of the water samples collected before chlorination were positive for microbiological contamination. All samples collected from systems where proper chlorination was taking place tested negative for microbiological contamination. However, the water from six tanks presenting structural problems continued to be distributed to the population despite contamination. The average residual chlorine level analyzed at the most distant terminal fountain was 0.29±0.2 mg/L, which is within the country's reference level 0.1-0.8 mg/L. The installation of water-chlorinator devices (WATA™) produces water without microbiological contamination and with chlorine levels within the WHO's recommended values. However, the success of the technology depends on the pre-existing structure of the water tank.

Dynamic cerebral autoregulation is impaired during submaximal isometric handgrip in patients with heart failure.

The incidence of neurological complications, including stroke and cognitive dysfunction, is elevated in patients with heart failure (HF) with reduced ejection fraction. We hypothesized that the cerebrovascular response to isometric handgrip (iHG) is altered in patients with HF. Adults with HF and healthy volunteers were included. Cerebral blood velocity (CBV; transcranial Doppler, middle cerebral artery) and arterial blood pressure (BP; Finometer) were continuously recorded supine for 6 min, corresponding to 1 min of baseline and 3 min of iHG exercise, at 30% maximum voluntary contraction, followed by 2 min of recovery. The resistance-area product was calculated from the instantaneous BP-CBV relationship. Dynamic cerebral autoregulation (dCA) was assessed with the time-varying autoregulation index estimated from the CBV step response derived by an autoregressive moving-average time-domain model. Forty patients with HF and 23 BP-matched healthy volunteers were studied. Median left ventricular ejection fraction was 38.5% (interquartile range: 0.075%) in the HF group. Compared with control subjects, patients with HF exhibited lower time-varying autoregulation index during iHG, indicating impaired dCA ( P < 0.025). During iHG, there were steep rises in CBV, BP, and heart rate in control subjects but with different temporal patterns in HF, which, together with the temporal evolution of resistance-area product, confirmed the disturbance in dCA in HF. Patients with HF were more likely to have impaired dCA during iHG compared with age-matched control subjects. Our results also suggest an impairment of myogenic, neurogenic, and metabolic control mechanisms in HF. The relationship between impaired dCA and neurological complications in patients with HF during exercise deserves further investigation. NEW & NOTEWORTHY Our findings provide the first direct evidence that cerebral blood flow regulatory mechanisms can be affected in patients with heart failure during isometric handgrip exercise. As a consequence, eventual blood pressure modulations are buffered less efficiently and metabolic demands may not be met during common daily activities. These deficits in cerebral autoregulation are compounded by limitations of the systemic response to isometric exercise, suggesting that patients with heart failure may be at greater risk for cerebral events during exercise.

Cerebral hemodynamics with intra-aortic balloon pump: business as usual?

OBJECTIVE: Intra-aortic balloon pump (IABP) is commonly used as mechanical support after cardiac surgery or cardiac shock. Although its benefits for cardiac function have been well documented, its effects on cerebral circulation are still controversial. We hypothesized that transfer function analysis (TFA) and continuous estimates of dynamic cerebral autoregulation (CA) provide consistent results in the assessment of cerebral autoregulation in patients with IABP. APPROACH: Continuous recordings of blood pressure (BP, intra-arterial line), end-tidal CO2, heart rate and cerebral blood flow velocity (CBFV, transcranial Doppler) were obtained (i) 5 min with IABP ratio 1:3, (ii) 5 min, starting 1 min with the IABP-ON, and continuing for another 4 min without pump assistance (IABP-OFF). Autoregulation index (ARI) was estimated from the CBFV response to a step change in BP derived by TFA and as a function of time using an autoregressive moving-average model during removal of the device (ARI t ). Critical closing pressure and resistance area-product were also obtained. MAIN RESULTS: ARI with IABP-ON (4.3 ± 1.2) were not different from corresponding values at IABP-OFF (4.7 ± 1.4, p = 0.42). Removal of the balloon had no effect on ARI t , CBFV, BP, cerebral critical closing pressure or resistance area-product. SIGNIFICANCE: IABP does not disturb cerebral hemodynamics. TFA and continuous estimates of dynamic CA can be used to assess cerebral hemodynamics in patients with IABP. These findings have important implications for the design of studies of critically ill patients requiring the use of different invasive support devices.

Cerebral Hemodynamic Effects of Cheyne-Stokes Respiration in a Patient with Stroke.

INTRODUCTION: Cheyne-Stokes respiration (CSR) and central sleep apnea (CSA) are common in patients with heart failure and/or stroke. We aim to describe the cerebrovascular effects of CSR during the acute phase of stroke in a heart failure patient. CASE REPORT: A 74-year-old male with previous dilated cardiomyopathy had sudden onset of right hemiparesis and aphasia. A transcranial Doppler was performed with continuous measurement of blood pressure (BP) (Finometer) and end-tidal CO2 (nasal capnography). Offline analysis of hemodynamic data disclosed relatively large periodic oscillations of both cerebral blood flow velocity and BP related to the CSR breathing pattern. Derivate variables from the cerebrovascular resistance were calculated (critical closing pressure and resistance-area product), demonstrating that there may be a myogenic impairment of cerebral blood flow (CBF) control in the affected hemisphere of this subgroup of patient. CONCLUSION: There is an impairment of CBF regulation in the affected hemisphere of the patient with ischemic stroke and CSR, highlighting the role of cerebral hemodynamic monitoring in this scenario.

Cerebral blood flow autoregulation in ischemic heart failure.

Patients with ischemic heart failure (iHF) have a high risk of neurological complications such as cognitive impairment and stroke. We hypothesized that iHF patients have a higher incidence of impaired dynamic cerebral autoregulation (dCA). Adult patients with iHF and healthy volunteers were included. Cerebral blood flow velocity (CBFV, transcranial Doppler, middle cerebral artery), end-tidal CO2 (capnography), and arterial blood pressure (Finometer) were continuously recorded supine for 5 min at rest. Autoregulation index (ARI) was estimated from the CBFV step response derived by transfer function analysis using standard template curves. Fifty-two iHF patients and 54 age-, gender-, and BP-matched healthy volunteers were studied. Echocardiogram ejection fraction was 40 (20-45) % in iHF group. iHF patients compared with control subjects had reduced end-tidal CO2 (34.1 ± 3.7 vs. 38.3 ± 4.0 mmHg, P < 0.001) and lower ARI values (5.1 ± 1.6 vs. 5.9 ± 1.0, P = 0.012). ARI <4, suggestive of impaired CA, was more common in iHF patients (28.8 vs. 7.4%, P = 0.004). These results confirm that iHF patients are more likely to have impaired dCA compared with age-matched controls. The relationship between impaired dCA and neurological complications in iHF patients deserves further investigation.

Is calcaneal broadband ultrasound attenuation a valid index of dual-energy x-ray absorptiometry-derived bone mass in children?

OBJECTIVES: The aim of the current study was to assess whether calcaneal broadband ultrasound attenuation (BUA) can predict whole body and regional dual-energy x-ray absorptiometry (DXA)-derived bone mass in healthy, Australian children and adolescents at different stages of maturity. METHODS: A total of 389 boys and girls across a wide age range (four to 18 years) volunteered to participate. The estimated age of peak height velocity (APHV) was used to classify children into pre-, peri-, and post-APHV groups. BUA was measured at the non-dominant heel with quantitative ultrasonometry (QUS) (Lunar Achilles Insight, GE), while bone mineral density (BMD) and bone mineral content (BMC) were examined at the femoral neck, lumbar spine and whole body (DXA, XR-800, Norland). Associations between BUA and DXA-derived measures were examined with Pearson correlations and linear regression. Participants were additionally ranked in quartiles for QUS and DXA measures in order to determine agreement in rankings. RESULTS: For the whole sample, BUA predicted 29% of the study population variance in whole body BMC and BMD, 23% to 24% of the study population variance in lumbar spine BMC and BMD, and 21% to 24% of the variance in femoral neck BMC and BMD (p < 0.001). BUA predictions were strongest for the most mature participants (pre-APHV R2 = 0.03 to 0.19; peri-APHV R2 = 0.05 to 0.17; post-APHV R2 = 0.18 to 0.28) and marginally stronger for girls (R2 = 0.25-0.32, p < 0.001) than for boys (R2 = 0.21-0.27, p < 0.001). Agreement in quartile rankings between QUS and DXA measures of bone mass was generally poor (27.3% to 38.2%). CONCLUSION: Calcaneal BUA has a weak to moderate relationship with DXA measurements of bone mass in children, and has a tendency to misclassify children on the basis of quartile rankings.Cite this article: B. K. Weeks, R. Hirsch, R. C. Nogueira, B. R. Beck. Is calcaneal broadband ultrasound attenuation a valid index of dual-energy x-ray absorptiometry-derived bone mass in children? Bone Joint Res 2016;5:538-543. DOI: 10.1302/2046-3758.511.BJR-2016-0116.R1.

The carotid artery as an alternative site for dynamic autoregulation measurement: an inter-observer reproducibility study.

The internal carotid artery (ICA) has been proposed as an alternative site to the middle cerebral artery (MCA) to measure dynamic cerebral autoregulation (dCA) using transcranial Doppler ultrasound (TCD). Our aim was to test the inter-operator reproducibility of dCA assessment in the ICA and the effect of interaction amongst different variables (artery source × operator × intra-subject variability). Two operators measured blood flow velocity using TCD at the ICA and MCA simultaneously on each side in 12 healthy volunteers. The autoregulation index (ARI) was estimated by transfer function analysis. A two-way repeated measurements ANOVA with post-hoc Tukey tested the difference between ARI by different operators and interaction effects were analysed based on the generalized linear model. In this healthy population, no significant differences between operator and no interaction effects were identified amongst the different variables. This study reinforced the validity of using the ICA as an alternative site for the assessment of dCA. Further work is needed to confirm and extend our findings, particularly to disease populations.

Influence of the CYP17 polymorphism on vasomotor symptoms in postmenopausal women: a pilot study.

OBJECTIVE: To evaluate the influence of CYP17 polymorphism on menopausal symptoms after estrogen treatment. METHODS: A total of 130 women were recruited, but only 100 of these were selected according to inclusion and exclusion criteria; they were treated with 0.3 mg/day conjugated equine estrogens. One year later, the study was completed by 71 women. The analysis of the Kupperman menopausal index symptoms was made with information provided by the patients on daily diary cards. Blood samples were analyzed and the women were divided into two groups based on the CYP17, 5'-untranslated region: group A (wild-type homozygote and heterozygote) and group B (mutated homozygote). RESULTS: The values for the Kupperman menopausal index were similar in both groups at baseline. The symptoms in both groups decreased after 1 year of treatment when compared to those at baseline. The improvement rate was approximately 27.09% and 32.18%, in groups A and B, respectively. The levels of estrogen after treatment were higher in both groups in comparison with the baseline values. The testosterone level rose in group B with the 1-year treatment (0.48 + 0.16 ng/ml), reaching a higher level than the level in group A after treatment. The sex hormone binding globulin (SHBG) level showed a significant increase after the 1-year treatment in group B, surpassing both the baseline and the after-treatment values in group A (p < 0.01). CONCLUSION: Our data suggest that the CYP17 polymorphism did not influence the action of estrogen on menopause symptoms during the 1-year treatment. The extra production of estrogen and androgen may have been countered by the elevation of SHBG levels.

CYP17 polymorphism and hot flushes in postmenopausal women.

OBJECTIVE: To investigate the association between the CYP17alpha gene polymorphism and hot flushes in postmenopausal women. METHODS: Ninety-three non-hysterectomized, postmenopausal women were enrolled in this study. Vasomotor symptoms were assessed at the baseline visit and based on information provided by each participant. The genotypic polymorphism of CYP17alpha gene was analyzed by PCR-RFLP assay using genomic DNA isolated from peripheral blood lymphocytes. RESULTS: Thirty-six women reported hot flushes of mild intensity, 25 reported hot flushes of moderate intensity and 32 of severe intensity. There was no significant difference between the severity of hot flushes and the CYP17 genotype or allele frequencies, 0.58 and 0.67 respectively. No association was found between hot flush severity and the CYP17 allele (odds ratio = 1.17, p = 0.61). CONCLUSION: The results of this study suggest that the CYP17 MspAI polymorphism was not significantly associated with an increased risk of reporting hot flushes.