Macaca mulatta) and airway hyperresponsiveness, but not atopy, and the suggestion was made that behavioral inhibition might index components of asthma that are not immune-related. In the present study, we prospectively examined the relationship between behavioral inhibition and airway hyperresponsiveness, and whether hormonal and immune measures often associated with asthma were associated with behavioral inhibition and/or airway hyperresponsiveness. In a sample of 49 yearling rhesus monkeys , we measured in vitro cytokine levels  in response to stimulation, as well as peripheral blood cell percentages, cortisol levels, and percentage of regulatory T-cells (CD3+CD4+CD25+FOXP3+). Airway reactivity was assessed using an inhaled methacholine challenge. Bronchoalveolar lavage was performed and the proportion of immune cells was determined. Behaviorally inhibited monkeys had airway hyperresponsiveness as indicated by the methacholine challenge (p = 0.031), confirming our earlier retrospective result. Airway hyperresponsiveness was also associated with lower lymphocyte percentages in lavage fluid and marginally lower plasma cortisol concentrations. However, none of the tested measures was significantly related to both behavioral inhibition and airway hyperresponsiveness, and so could not mediate their relationship. Airway hyperresponsiveness is common to atopic and non-atopic asthma and behavioral inhibition has been related to altered autonomic activity in other studies. Our results suggest that behavioral inhibition might index an autonomically mediated reactive airway phenotype, and that a variety of stimuli  may trigger the airways response.Behavioral inhibition reflects a disposition to react warily to novel situations, and has been associated with atopic diseases such as asthma. Retrospective work established the relationship between behavioral inhibition in rhesus monkeys ( Asthma is a chronic disease marked by hyperresponsive airways and inflammation in the lung, and has long been recognized as having a substantial psychological component While the previously described studies are compelling, many used a broad definition of asthma, and relied on self- or parent-reports rather than biological measures. In addition, the designs of most of these studies do not permit the understanding of whether behavioral inhibition precedes asthma, follows asthma, or if a third factor underlies both BI and asthma. Finally, nearly all of the studies investigating psychological functioning and asthma have not distinguished between two broad types of asthma (atopic vs. non-atopic). Airway hyperresponsiveness (AHR) and inflammation characterize both types of asthma; atopic  asthmatics, however, react to a known aeroallergen, which typically triggers the airways response, while non-atopic  asthmatics do not Understanding mechanisms of how BI might relate to asthma can be substantially enhanced through use of an animal model, and monkey models have been especially valuable in recapitulating most aspects of asthma in humans H2) cytokine IL-4, which could promote an asthmatic phenotype through recruitment of inflammatory cells  to the airway H1) cytokines , which are considered protective Regs) Regs in peripheral blood, which suppress TH2-type responses and have been found to be higher in healthy subjects Regs, cortisol, complete blood counts (CBCs), and bronchoalveolar lavage fluid (BALF) differential counts].Although our previous study showed that behavioral inhibition was associated with AHR Macaca mulatta; 24 males). All animals were born into one of 21 outdoor, half-acre, field corrals at the California National Primate Research Center (CNPRC). Corrals were constructed of chain-link sides and top, and contained a natural substrate, several wooden A-frame structures and canopy for protection from wind and rain, perches in multiple locations throughout the cage, and several other climbing structures used as enrichment. Each cage contained up to 150 animals of all age and sex classes. Animals were provided water ad libitum and fed laboratory monkey chow  twice a day in the morning between 0700 and 0800 and in the afternoon between 1400 and 1500. Twice weekly, fruit and vegetable supplements were provided. In addition, trained animal care technicians checked animals’ health daily. All subjects were assessed at both infant and yearling time points.Subjects were 49 gonadally-intact rhesus monkeys , they were placed in an individual holding cage in the morning and provided with a cloth diaper, stuffed terry cloth duck, and a novel object. To better understand responses to relocation and maternal separation, infants were hand-caught to obtain blood samples and behavioral assessments were done in the holding cage. Infants were provided with monkey chow, water, and fruit-flavored juice and were supplemented with fruit.For yearling assessments, animals were removed from the outdoor corral for 4 days and placed in an indoor holding cage. Animals were provided with water ad libitum and monkey chow twice daily, in the morning (between 0700 and 0800) and afternoon (between 1400 and 1500). Yearlings were provided with additional enrichment including a Nylabone Dental Chew  and a mirror.Between 93 and 124 days of age (mean = 110.2), all animals participated in CNPRC’s BioBehavioral Assessment (BBA) program, which was designed to assess animals’ behavioral and physiological responsiveness and temperament. Details are described elsewhere H1/TH2 cytokines), complete blood count (CBC), and peripheral blood mononuclear cell (PBMC) isolation for immunophenotyping of TRegs. On Day 3 of relocation, the animal's lung function was assessed via airway responsive testing. On Day 4 of relocation (n = 38), bronchoalveolar lavage fluid sampling occurred. Yearling assessments and study design are shown in When subjects were yearlings , animals were briefly net-caught in their field corrals at 0900 h and again at 1500 h on the same day, and blood was sampled from the femoral vein for later assessment of plasma cortisol concentrations see . BetweenAirway responsiveness testing and BALF sampling were performed under ketamine and propofol anesthesia and efforts were made to minimize suffering of animals by having a veterinarian or clinical veterinary technician present throughout all procedures to monitor the status of the animal; procedures were terminated when oxygen saturation fell below 70% of baseline. After physiological data collection, a veterinarian or clinical veterinary technician monitored animals regularly until the animal was able to sit up. Animals’ health was checked daily during experimental procedures. No animals were sacrificed for this study; at the end of the yearling assessment period, animals were returned to their corrals. All procedures were approved by the University of California, Davis, Institutional Animal Care and Use Committee (Protocol Number: 15344) and followed the Guide to the Care and Use of Laboratory Animals of the National Institutes of Health. The University of California Davis and the CNPRC are accredited by the Association for Assessment and Accreditation of Laboratory Animal Care.At each time point where cortisol was to be measured, we centrifuged 0.5 ml of whole blood from each sample for 10 minutes at 1900 g at 4°C. Plasma was removed and decanted into tubes for storage at −80°C and was later assayed in duplicate using commercially available kits . Inter- and intra- assay coefficients of variation were 5.4% and 3.4%, respectively.2, then plates were briefly centrifuged and pellets were stored in RNALater  for a time period of 4–6 months at −80°C for mRNA extraction. We quantified relative gene expression of cytokines using quantitative polymerase chain reaction (qPCR) for IL-4 (NCBI accession no. NM_001032904), IL-10 (NCBI accession no. NM_001044727), IL-12 (NCBI accession no. NM_001044725), and IFN-γ (NCBI accession no. NM_001032905).Heparinized whole blood was diluted 1.25∶1 with DMEM culture media  and stimulated with staphylococcal enterotoxin B (SEB)  in a sterile 24-well plate. The final well concentrations were 500 ng/ml SEB. Cultures were incubated for 24-hours at 37°C in an atmosphere of 5% COWe extracted total RNA from stimulated cells with the RiboPure Blood kit  with modifications of manufacturer’s instructions . Concentq) values. The qPCR reaction was run at 50°C for 2 minutes, 95°C for 10 minutes, and 45 cycles of 95°C for 15 seconds and 60°C for 1 minute. Each sample was run in duplicate with standard deviations <0.5. We analyzed the qPCR results using the Applied Biosystems Sequence Detection System software (SDS v. 2.2.1), and we normalized gene expression using GAPDH (NCBI accession no. NM_001195426). In rhesus monkeys, GAPDH has been shown to be a reliable and valid reference gene q test gene – Cq normalizer)] values were used for gene expression.We ordered qPCR primers and probes from Integrated DNA Technologies  and Applied Biosystems  respectively . The qPC5 cells per sample) in PBS as previously described Reg population We isolated peripheral blood mononuclear cells using a Ficoll density gradient , then cells were washed twice with Hanks’ modified medium. Cells were cryopreserved in 90% fetal bovine serum (FBS) and 10% DMSO for later immunophenotyping by resuspending . All electronic counts were verified by a manual differential. Values were expressed as percentages to be consistent with presentation of BALF data.Airway responsiveness to doubling concentrations of inhaled methacholine aerosols was quantified using previously published procedures Animals were anesthetized with ketamine (10 mg/kg) and anesthesia was maintained with propofol (0.1 mg/kg/min). As described previously To test our hypotheses that behaviorally inhibited animals would show a significant relation to AHR and that this relationship would be mediated by asthma-relevant measures, we intended to use a mediation model based on Baron and Kenny Chi-Square = 3.471, p = 0.031)  . Raw valBivariate analyses revealed that sex was associated with percentage of eosinophils in lavage fluid (p = .054), age was associated with IFN-γ gene expression (p = .049) and sample collection time was related to the AM outdoor cortisol value ; consequently, partial correlations are reported for these measures. All other variables showed no effects of age and sex (p>.102), thus Pearson correlations are presented. Several correlation coefficients between BI/AHR and the potential mediating variables were significant ; howeverBehaviorally inhibited animals had lower levels of SEB-stimulated IFN-γ expression  . Gene exHyperresponsive animals had marginally lower cortisol concentrations in the natal cage at the AM time point  .Individuals with AHR had a lower percentage of lymphocytes  in lavage fluid and a marginally higher percentage of blood monocytes . Behaviorally inhibited animals showed a trend toward a lower percentage of eosinophils in BALF  and a significantly higher percentage of blood eosinophils  . DescripH1/TH2 cytokines, TRegs, plasma cortisol concentrations, and cell differentials (blood and BALF), and found that, although there were some significant relationships between the potential mediators and either BI or AHR, none of the tested measures was significantly related to both BI and AHR; consequently, a mediational analysis could not be performed. While we recognize that our list of possible mediators was not exhaustive, we believe our data provide further evidence that the role of temperament in asthma might be unrelated to the immune component of the airways response.Animals identified in infancy as behaviorally inhibited  were significantly more likely, compared to controls, to display airways hyperresponsiveness  approximately one year later, confirming our previous retrospective results Consistent with our earlier retrospective study While we found some significant  correlations between our measures of BI and AHR on the one hand and potential neuroendocrine and immune mediators on the other hand, there were no neuroendocrine or immune measures that were related to both BI and AHR; consequently, we could not identify any mediators of the BI-AHR relationship. We recognize that we did not test all possible mediators and that future research may identify such a relationship. Here, we discuss the relationships that were found.H2 disposition H2 cytokines and decreased expression of TH1 cytokines. We did find that behaviorally inhibited animals showed decreased IFN-γ (TH1 cytokine) expression, but IFN-γ expression was unrelated to AHR. In addition, IL-10 has been thought to have a role in effective suppression of allergic responses of the lung and is a utilized pathway of suppression by TRegsH1/TH2 explanation.Asthma has been commonly characterized by a TH1 to a TH2 response Asthmatics and individuals with atopic disorders have been shown to have attenuated cortisol concentrations when compared to controls H2-like T-lymphocytes in BALF, even in the absence of differences in overall numbers of lymphocytes We found that hyperresponders showed a lower percentage of lymphocytes in lavage fluid and a marginally higher percentage of monocytes in blood . Asthma Few studies have examined how BI relates to immune function. Behaviorally inhibited rhesus monkeys show reduced measures of cellular immunity (reduced lymphocyte proliferation to mitogens) compared to controls Overall, we believe these results provide a new focus for future studies, and suggest that the role of temperament in asthma may be unrelated to the immune component of asthma; rather BI and AHR may both be indicators of a particular central and autonomic nervous system organization. A common feature of both BI and AHR is altered autonomic reactivity: behaviorally inhibited children have shown alterations in heart period compared to non-behaviorally inhibited children Asthma has long been associated with psychological functioning, and the current study used a prospective methodology in an animal model to relate BI to the airways response. The present study did not elucidate the mechanism by which AHR and BI are related. However, we believe that the monkey model could be valuable in further understanding the development of AHR in behaviorally inhibited individuals from infancy by investigating simultaneously autonomic function and neural control of lung tissue. Should such a relationship be established, this model could be very useful for developing interventions to prevent the development of AHR.Table S1Primer and probe sequences.(XLSX)Click here for additional data file.Table S2Raw EC200 values for each animal.(XLSX)Click here for additional data file.Supporting Information S1List of modifications to RiboPure - blood procedure.(DOC)Click here for additional data file.


EHP 120(2):241–246; Hoffmann et al.]. In a study of the short-term effects of ambient air pollutants and temperature on arterial blood pressure in 70 people with type 2 diabetes mellitus, they found opposing effects—fine particulate matter (PM2.5) and black carbon in particular, were associated with increases in systolic blood pressure (SBP), whereas ozone and higher temperature were associated with decreases.A body of research suggests that people with diabetes may be especially vulnerable to adverse cardiovascular effects of air pollution and heat, although the combined effects of these factors are not clear. Now an international team of researchers sheds light on potential impacts of this dual exposure [The study subjects, from the Boston, Massachusetts, area, ranged in age from 45 to 86 and were evaluated between September 2006 and August 2010. Each participant lived within 25 km of a central air pollution monitor. At each of 5 clinic visits spaced 2 weeks apart, participants answered questions and underwent blood and urinary analyses and clinical examinations. Mixed models that accounted for repeated measures in individual participants were used to estimate associations between air pollutants and temperature and blood pressure.2.5 or black carbon in the 5 days prior to a clinical examination was linked with an average increase in SBP of 1.4 mmHg and 2.2 mmHg, respectively. In contrast, an interquartile increase in ozone was associated with a 5.2-mmHg decrease in SBP. Each increase of 11.5°C in mean temperature was associated with a 3.2-mmHg decrease in SBP before adjusting for ozone exposure. Estimated increases in blood pressure with PM2.5 exposure were greater in people with elevated baseline blood pressure, whereas associations with ozone exposure and temperature were greater in people with lower to normal blood pressure. Estimated differences in blood pressure tended to be progressively greater for each of up to 5 additional days of exposure prior to each clinical exam.The researchers estimated that each interquartile increase in PMThe researchers accounted for possible confounding factors such as sociodemographic variables, lifestyle indicators, prescription drug use, tobacco smoke, health history, and season. However, they were not able to estimate personal levels of exposure using the local and area monitoring stations, and factors such as physical activity were not addressed.The authors note that the opposing effects may not cancel each other out and could plausibly act negatively in independent ways. Decreased SBP can be good in moderation, but it could be dangerous if lowered suddenly and significantly, especially in subjects with compromised vascular compensation mechanisms, which is common in diabetic patients.


Non-renal determinants are important for the interpretation and appraisal of the diagnostic and prognostic value of any endogenous kidney function marker.β2-microglobulin has been increasingly investigated as a diagnostic marker of kidney function and a prognostic marker of adverse outcomes. To date, non-renal determinants of β2-microglobulin levels have not been well describedwww.seniorlabor.ch study, which includes subjectively healthy individuals aged ≥60 years. Factors known or suspected to have a non-renal association with kidney function markers were investigated for a non-renal association with serum β2-microglobulin. As a marker of kidney function, the Berlin Initiative Study equation 2 for the estimation of the estimated glomerular filtration rate (eGFRBIS2) in the elderly was employed.This cross-sectional analysis was performed within the framework of the BIS2) revealed age, male gender, and C-reactive protein level to be positively associated with β2-microglobulin levels. In addition, there was an inverse non-renal relationship between systolic blood pressure, total cholesterol and current smoking status. No association with markers of diabetes mellitus, body stature, nutritional risk, thyroid function or calcium and phosphate levels was observed.A total of 1302 participants  were enrolled in the study. The use of a multivariate regression model adjusting for age, gender and kidney function  and remind of classical cardiovascular risk factors. The glomerular filtration rate (GFR) is commonly regarded as the most reliable global index of kidney function Serum markers of kidney function have a reciprocal relationship with the GFR, i.e., serum marker levels increase with decreasing GFR and vice versa Serum creatinine is influenced by age, gender, skin color and ethnicity, body habitus, chronic illness, nutritional status and diet Because non-renal determinants are important for the interpretation and appraisal of the diagnostic and prognostic value of any endogenous kidney function marker, we aimed to study the association of non-renal factors with the serum β2-microglobulin concentration. Factors investigated for a non-renal association with kidney function markers in other studies were chosen for the present analysis.http://www.seniorlabor.ch). Consecutive subjectively healthy elderly volunteers aged 60 years and older were recruited, as previously described The study participants were recruited from August 2009 to November 2010 within the context of the Seniorlabor Study, which is an ongoing investigation in the canton of Berne (Switzerland) aimed at establishing appropriate reference intervals of several analytes in the elderly  after an overnight fasting period. The laboratory samples were processed  immediately after the blood was drawn. The geriatric nutritional risk index (GNRI) score, modified by Yamada et al. In this equation, the ratio of the actual body weight to the ideal body weight is set to one when the patient’s body weight exceeds the ideal body weight. Ideal body weight was defined as the value calculated from height and a BMI of 22 The laboratory parameters were determined with various analytical platforms. The β2-microglobulin concentration was determined using an Immulite 2000 .BIS2 is calculated as follows The IDMS-standardized creatinine  concentrations and albumin levels were determined on a Cobas Integra 800 instrument . The cystatin C level was determined using a nephelometric method on a Siemens ProSpec . The results were standardized to the International Federation of Clinical Chemistry and Laboratory Medicine standard, as described by Inker et al. The level of high-sensitivity CRP was determined on a Siemens ProSpec . The concentrations of albumin, calcium, glucose, phosphate and potassium were assayed on a Cobas Integra 800 instrument . The hemoglobin and white blood cell (WBC) count were measured on a Sysmex XE-5000 hematology analyzer . The thyroid-stimulating hormone (TSH) level was determined using an Architect 4000i , and the hemoglobin A1c (HbA1c) level was determined using high-performance liquid chromatography . The inter-day coefficients of variation, determined with commercially available control materials, were as follows: 7.30% at 1.22 mg/L and 8.32% at 3.18 mg/L for β2-microglobulin; 3.75% at 0.37 mg/L and 3.43% at 0.44 mg/L for cystatin C; 4.27% at 42 µmol/L and 1.96% at 556 µmol/L for creatinine; 3.7% at 24 g/L and 2.1% at 42 g/L for albumin; 6.7% at 0.64 mmol/L and 2.4% at 2.21 mmol/L for phosphate; 2.0% at 2.53 mmol/L and 2.0% at 3.25 mmol/L for calcium; 2.2% at 3.5 mmol/L and 1.9% at 6.5 mmol/L for glucose; 5.38% at 5.8 g/L and 4.87% at 44.7 g/L for CRP; 2.95% at 0.78 nU/L and 3.29% at 27.7 mU/L for TSH; and 2.88% at 5.7% and 2.38% at 10.8% for HbA1c.c, potassium, sodium, total cholesterol, triglycerides, calcium, phosphate, albumin, CRP, and TSH. Continuous variables were log transformed if they were not normally distributed. These models considered β2-microglobulin as a dependent variable and other clinical and laboratory parameters as independent variables. Unadjusted associations were calculated. Furthermore, these associations were adjusted for kidney function, as assessed with eGFRBIS2, age and gender. Finally, a model employing all of the significant predictors in the aforementioned adjusted associations was fit. For the multivariate models, partial correlation coefficients rpartial were calculated. These coefficients estimated the correlation of each variable with log β2-microglobulin, adjusted for the effect of the other variables in the model. The comparisons between the two groups were performed with the Mann-Whitney U-test. Proportions were compared using the chi-square test. For all comparisons, P values <0.05 were considered to be significant. p-values up to 0.20 are reported numerically, whereas p-values >0.2 are reported as not significant (n.s.). All calculations were performed with MedCalc software version 12.2.1 .The data are presented as medians and interquartile ranges (IQRs) or mean ± standard deviation, depending on the assessment with the Pearson d’Agostino test. To determine whether the β2-microglobulin concentrations were associated with non-renal factors, linear regression models were used. As candidate predictors, variables known to be independently from kidney function being associated with other endogenous markers of GFR BIS2 was 73 ml/min/1.73 m2 . An eGFRBIS2<60 ml/min/1.73 m2 was present in 20.20% of the participants, whereas an eGFRBIS2>90 ml/min/1.73 m2 was found in 9.83%. There were no significant gender-specific differences in age, systolic and diastolic blood pressure, eGFRBIS2, albumin, HbA1c, potassium or CRP. However, female participants had a significantly lower BMI, weight, height, GNRI score, smoking prevalence, cystatin C level, creatinine level, β2-microglobulin level, blood urea nitrogen level, hemoglobin level, fasting glucose level and WBC count. Males had lower calcium and phosphate levels than females. Although statistically significant, these gender-specific differences, with the exception of serum creatinine and hemoglobin levels, were small. The Spearman rank correlation coefficient of the reciprocal of β2-microglobulin and eGFRBIS2 was 0.70 (P<0.001). The relationship between the inverse β2-microglobulin levels and eGFRBIS2 is given in A total of 1302 individuals  with a median age of 72 years and an IQR of  were included in the study. All participants were of Caucasian descent. The detailed characteristics of the study population are given in BIS2. Fitting these models revealed that age, gender, systolic blood pressure, current smoking, potassium level, total cholesterol, CRP level and WBC count were non-renal predictors of β2-microglobulin concentrations. β2-microglobulin increased with age, male gender, CRP levels and WBC levels. In contrast, β2-microglobulin levels were inversely associated with increasing systolic blood pressure, total cholesterol and current smoking status. There did not seem to be a non-renal association between markers of diabetes mellitus, body stature, nutritional risk, thyroid function or calcium and phosphate levels and β2-microglobulin levels.Non-renal factors associated with log β2-microglobulin were assessed by adjusting the linear regression models for log age, gender and log eGFRFinally a model incorporating all significant predictors from the aforementioned adjusted models was fitted, as shown in This cross-sectional study in a population of subjectively health elderly participants predominantly having mild to moderate impairment of kidney function Understanding the non-renal determinants of an endogenous serum marker of kidney function is important because this understanding allows for the identification of variables to be used in the equations to transform a serum value into the corresponding eGFR Interestingly, we did not find non-renal associations between β2-microglobulin and body weight or body mass index (BMI). This finding is in line with the findings described by Filler et al. Serum β2-microglobulin levels can increase as an acute phase reactant in several diseases. Accordingly, increased levels have been found in autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis and Sjögren’s syndrome, as well as in lymphoproliferative and infectious diseases Our study identified smoking to be a non-renal factor associated with β2-microglobulin levels. Our multivariate model indicates that this association is independent from inflammation. This is in contrast to the report by Juraschek et al. Non-renal determinants are important for the interpretation and appraisal of the diagnostic and prognostic value of any endogenous kidney function marker. For example, it does not make much sense to assess kidney function with a creatinine-based GFR estimate in patients with reduced muscle mass due to spinal cord injury. For this purpose, cystatin C has been shown to have better diagnostic characteristics than serum creatinine However, more studies are necessary before the β2-microglobulin can be used as a kidney function marker in clinical routine. First, β2-microglobulin methods should be standardized Our study has several limitations. First and most importantly, we estimated GFR and did not use a reference method directly measuring GFR by means of exogenous substances. Direct GFR measurement does not undergo non-renal modification and allows for definitive answers. Logistically, it would have been impossible for us to perform direct GFR measurements in such a large population. Although we did not use a reference method for GFR assessment, we used the most accurate routine methods currently available, which rely on two serum markers and represent the appropriate methods for the population under study The serum concentration of β2-microglobulin was demonstrated to be associated with several non-renal factors, such as age, gender, CRP, cholesterol, systolic blood pressure, gender and current smoking. All these factors represent major cardiovascular risk factors. Our findings were derived from elderly individuals and cannot be extrapolated to the general population. Elderly patients, however, represent a collective with frequent need for determination of kidney function. Several factors affecting serum cystatin C levels, such as thyroid dysfunction, weight and hemoglobin concentrations, did not exhibit a non-renal association with β2-microglobulin. Information on non-renal factors associated with β2-microglobulin will allow for the identification of clinical scenarios where other kidney function markers, such as cystatin C and creatinine, are unable to provide adequate answers.Figure S12. The limits of agreement are −32.3 to +12.2 ml/min/1.73 m2. The eGFRBIS2 is used as a reference method for determining kidney function.Introducing β2-microglobulin values from the Siemens Immulite into the equation by Donadio (TIF)Click here for additional data file.


Obesity in children is one of the medical and public health problems of the most attention today, because of an increasing incidence. Obesity is associated with dyslipidemia and increased blood pressure will increase risk for cardiovascular and metabolic disease.To determine association between blood pressure with lipid profile in obese adolescents in the city of Padang.This study is part of a study on obese adolescent in Padang. A cross - sectional study was conducted in 2010 with population of high school students in Padang by anthropometric measurements, blood pressure and blood lipid profile examination. Data were analyzed with SPSS 19 with chi square test and ANOVA with 95% confidence level.Increased blood pressure occurred in 32% of all samples with 27% of prehypertension and 5% hypertension. Dyslipidemia, cholesterol levels, high LDL and triglycerides and low HDL levels found respectively 40%, 41.3%, 25% and 43.8% of the total sample. Obese adolescents with increased blood pressure have high triglyceride levels compared with obese adolescents with normal blood pressure, (40.6% vs 14.6% with P 0.009).Obese adolescents has risk for the occurrence of dyslipidemia and hypertension. Hypertension in obese adolescents is mainly associated with high triglyceride levels.


Patients undergoing hemodialysis treatment have a six-fold increased risk for stroke relative to the general population. However, the effect of hemodialysis on cerebral blood flow is poorly studied and confounding factors like blood pressure and ultrafiltration as well as temperature changes have rarely been accounted for. The aim of our study was to use state-of-the-art technology to evaluate the effect of a single dialysis session on cerebral perfusion as well as on vascular stiffness.Chronic hemodialysis patients  were recruited. Cerebral blood flow and arterial pulse wave velocity were measured before and immediately after a hemodialysis session. To exclude effects of volume changes we kept ultrafiltration to a minimum, allowing no change in body weight. Isothermic conditions were maintained by using the GENIUS single-pass batch-dialysis system with a high-flux polysulfone dialyser. Cerebral blood flow was measured by contrast-enhanced computed tomography. Pulse wave velocity was measured using the SphygmoCor  device by a single operator.This study shows for the first time that isovolemic, isothermic hemodialysis neither affected blood pressure or heart rate, nor total or regional cerebral perfusion. There was also no change in pulse wave velocity.Mechanisms other than the dialysis procedure itself might be causative for the high incidence of ischemic strokes in this patient population. Moreover, the sole removal of uremic toxins does not lead to short-term effects on vascular stiffness, underlying the importance of volume control in this patient population. The high prevalence of cardiovascular disease in chronic kidney disease (CKD) stage 5 D, i.e. dialysis patients has been known for decades The study protocol was approved by the Hannover Medical School Ethics Committee (protocol # 3952). Stable adults undergoing chronic hemodialysis treatment were studied after written informed consent was obtained from the patients.Participants included were undergoing chronic hemodialysis for at least one year with a regimen of at three times per week. None of the patients suffered from instable coronary artery disease or had signs of severe heart failure (>NYHA II). The patients had no signs of infections based on c-reactive protein (CRP) and clinical examination. Exclusion criteria were participation in other studies during the previous three month, allergy against contrast agents or iodine, hyperthyroidism or unclear dysfunction of thyroid gland, premenopausal women, history of radiation of the cranium, residual diuresis (≥500 ml/day), history of stroke within six weeks prior to study participation, taking nutrition supplements containing L-arginine, and any further conditions at the discretion of the treating physician.The study participation took place on the patient’s midweek dialysis day. After measurement of the predialysis body weight, heart rate, blood pressure and body temperature the dialysis needles  were placed as usual in the dialysis fistula and a blood gas analysis (BGA) including determining sodium and potassium was performed.Afterwards the patient was taken to the computed tomography (CT) scan in supine and resting position, to rule out influences by altered hemodynamics. The initial CT-scan was performed as described below and the patient was taken back to the dialyis unit. The four hour lasting dialysis session was performed using the Genius®  single-pass batch-dialysis system with a high-flux polysulfone dialyser FX 60 . The dialysis solution was composed according to the patient’s requirements. The blood flow and the countercurrent dialysate flow ranged between 200 and 250 ml/min, there was no net ultrafiltration. After 4 hours the patients underwent a second pulse wave analysis and subsequently a second CT.The method used was described previously and adapted due to modified CT hardware Carotid-aortic PWV was determined using a validated system , which employs high-fidelity applanation tonometry by a pencil-type probe for non-invasive registration of peripheral arterial pressure waves. Pulse waveforms of the common carotid artery and the femoral artery were obtained sequentially and PWV was calculated as the distance between the suprasternal notch and the femoral artery recording site minus the distance between the suprasternal notch and the carotid artery recording site, divided by the time interval between the feet of the flow waves. The device uses the foot-to-foot methods as described previously Body temperature was measured with an infrared tympanic thermometer  with an accuracy of +/−0.1°C.2 or pH changed significantly Click here for additional data file.


Serotonin promotes pulmonary arterial vasoconstriction and pulmonary arterial smooth muscle cell proliferation, thereby having the potential to increase pulmonary arterial blood pressure. Although serotonin reuptake inhibitors (SRIs) might inhibit further deterioration in patients with manifest pulmonary arterial hypertension, they may induce pulmonary hypertension in healthy newborns after fetal exposure. As it is unclear whether treatment with SRIs affects pulmonary hemodynamics in adults without pulmonary hypertension, the aim of the present study was to investigate the effect of SRIs on pulmonary hemodynamics in such subjects.2A receptor gene polymorphisms and platelet 5-HT2A receptor expression were studied to elucidate their possible role as modifying factors.Sixteen patients with stable angina pectoris scheduled for first time coronary artery bypass grafting were included in the study. Of these 8 were currently treated with an SRI (the SRI group) and 8 were not (the control group). Pulmonary arterial pressures were measured before induction of anesthesia by means of a pulmonary artery catheter. Serotonin transporter and 5-HT2A receptor expression did not influence the hemodynamic variables.No patients in any of the groups had pulmonary arterial hypertension. Mean pulmonary artery pressure was 15.0 mmHg in the SRI group and 14.5 mmHg in the control group . Neither were there any significant differences between the groups for any of the other hemodynamic variables studied. The various gene polymorphisms and the extent of platelet 5-HTSRI treatment did not significantly influence pulmonary hemodynamics in patients without pulmonary hypertension.Serotonin; Selective serotonin reuptake inhibitors; Pulmonary hemodynamics; Pulmonary hypertension Serotonin  promotes both pulmonary arterial vasoconstriction and pulmonary arterial smooth muscle cell proliferation . ElevateSerotonin was first linked to pulmonary arterial hypertension in the late 1960s through the association between the use of anorectic agents and the development of pulmonary arterial hypertension. Although somewhat controversial, one suggested mechanism is that anorectic drugs such as aminorex and dexfenfluramine increase circulating serotonin levels, with subsequent serotonin receptor stimulation . Even thSelective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, citalopram, paroxetine and sertraline are widely used in the treatment of depression and anxiety disorders. In animal models, serotonin-induced proliferation of pulmonary artery smooth muscle cells as well as experimentally induced pulmonary arterial hypertension is inhibited by SSRIs . NotablyAlthough SSRIs might protect against pulmonary arterial hypertension and tend to lower pulmonary arterial blood pressure in adults, the situation seems to be the opposite in newborns after fetal exposure. In two studies, the risk of persistent pulmonary arterial hypertension was increased 6.1-fold and 3.6-fold, respectively, after maternal use of SSRIs in late pregnancy ,16. A thThe serotonin transporter is encoded by a single gene, SERT . A polymorphism on the upstream promoter region of the SERT gene has been characterized with two separate forms, long (L) and short (S). The L allele induces an increased rate of gene transcription compared to the S allele, thereby increasing the expression of the transporter. In animal models, overexpression of the human SERT gene has resulted in more severe hypoxia-induced pulmonary arterial hypertension . In a st1B, 5-HT2A and 5-HT2B receptors, have been suggested to mediate the vasoconstrictive effect of serotonin. Species differences might exist as to which receptor is the most central. In rats, 5-HT2A receptor blockade inhibits the development of pulmonary arterial hypertension lysergic acid diethylamide ([3H]LSD) ranging from 0.25 to 2.5 nM . Non-specific binding was assessed in the presence of 300 nM spiperone . The binding was terminated by cell harvester filtration through Whatman GF/C  filters prewashed in a 0.3% solution of polyethylenimine. The radioactivity trapped by the filters was determined by liquid scintillation spectroscopy. The final protein concentrations were measured, and the binding characteristics (Bmax and Kd) for [3H]LSD binding were calculated from Scatchard analysis of the specific binding data according to the method of least squares linear regression.The method for radioligand binding to the platelet 5-HTlsewhere . In brieGenomic DNA was extracted from whole blood collected in EDTA-treated tubes, using a Qiagene Blood and Cell Culture DNA kit , according to the manufacturer’s guidelines. The polymorphisms were identified as follows:2, 2 x of a mixture of dNTPs , 0.5 x DMSO (Sigma), 0.3 μM of each primer and 2.5 U of AmpliTaq Gold  and 100 ng of genomic DNA. The conditions for the amplification were an initial denaturing step of 95 ºC for 8 min, followed by 33 cycles of 95 ºC for 30 sec, 66 ºC for 30 sec, 72 ºC for 45 sec, and a final elongation step of 72 ºC for 10 min. The PCR products were separated and detected in ethidium bromide 2.5% NuSieve 3:1 Agarose gel .For the 5HTTLPR polymorphism the upstream region of the serotonin transporter gene was amplified using primers described previously , which o2, 1 mM of MgCl2, 0.5 μg of purified BSA 100 x , 200 μM mix of each nucleotide, 0.25 μM of primer ex1F, 0.5 μM of primer ex1R, 0.20 μM of each probe, 1 U of Taq DNA Polymerase (Roche) and 30 ng of genomic DNA. The conditions for the amplification were an initial denaturating step of 95 ºC for 2 min, 40 cycles of 95 ºC for 2 sec, 58 ºC for 10 sec, 72 ºC for 12 sec, and a melting curve of 0.5 ºC/sec.For the 5HTR2A 102 T > C, Thr25Asn, His452Tyr and 516 C > T polymorphisms a real-time PCR was performed to genotype the polymorphism in a Light Cycler 4.0 system (Roche Bioscience) with a set of specifically designed primers and probes. The 5HTR2A 102 T > C and Thr25Asn polymorphisms were carried out in a duplex PCR in a final volume of 10 μL containing 1 x PCR buffer/MgCl2, 2.5 mM of MgCl2, 0.5 μg of purified BSA 100 x (New England Biolabs), 200 μM mix of each nucleotide, 0.2 μM of primer HTR2A-F, 0.5 μM of primer-anchor ILC HTR2A, 0.15 μM of sensor C, 1 U of Taq DNA Polymerase (Roche Bioscience) and 30 ng of DNA. Amplified conditions were an initial denaturating step of 95 ºC for 1 min, 40 cycles of 95 ºC for 5 sec, 58 ºC for 10 sec, 72 ºC for 12 sec, and a melting curve of 1 ºC/sec. The 5HTR2A 516 C > T polymorphism was performed in a final volume of 10.5 μL containing 1 x PCR buffer/MgCl2, 0.5 mM of MgCl2, 0.5 μg of purified BSA 100 x (New England Biolabs), 200 μM mix of each nucleotide, 0.25 μM of primer 516-as, 0.5 μM of primer 516-F, 0.15 μM of each probe, 1 U of Taq DNA Polymerase (Roche) and 30 ng of genomic DNA. The conditions for the amplification were an initial denaturation step of 95 ºC for 2 min, 40 cycles of 95 ºC for 1 sec, 57 ºC for 10 sec, 72 ºC for 10 sec, and a melting curve of 1 ºC/sec.The 5HTR2A His452Tyr polymorphism was carried out in a final volume of 10.5 μL containing 1 x PCR buffer/MgClNo previous investigations on possible differences in pulmonary artery pressures between patients treated with SRIs and control patients were identified. The sample size calculations were based on the following assumptions: In a previous study, the standard deviation of MPAP in CABG patients was found to be 3.1 mmHg . We consData are presented as means (SD) and medians (range) as appropriate. Statistical analyses were carried out using the program package SPSS for Windows, version 15.0 . Data were compared using Student’s t-test or Wilcoxon-Mann-Whitney U test for scale variables, and Fisher’s exact test for categorical variables. P values < 0.05 were considered statistically significant.Eight patients treated with an SRI for more than six weeks and 8 control patients were included in the study. No patients were excluded after inclusion. Patient characteristics, medical data, and data on surgical procedures are presented in max and Kd for [3H]LSD binding are presented in max or Kd for [3H]LSD binding and pulmonary artery pressure neither in the SRI group, in the control group, nor in the total material , venlafaxine. However, at doses used in clinical practice, the effect on the serotonin transporter is the same for all drugs belonging to the SSRI/SNRI classes. Moreover, with the exception that venlafaxine has some effect on the noradrenaline transporter, the pharmacodynamic profile of the drugs studied is identical. We thus consider that the principal result of the present study would have been the same irrespective of which serotonin reuptake inhibitors we had included.max or Kd for platelet 5-HT2A receptor binding between the SRI and control groups. Whereas Bmax expresses the density of receptors on the platelet membrane, Kd represents an inverse value of the affinity of the ligand to the receptor. Given previous findings indirectly indicating that activation of the receptor might play a role for the development of pulmonary arterial hypertension [max values are associated with higher pulmonary arterial pressures can be raised. However, no such relationships could be revealed in the present study, neither in the SRI group, in the control group nor in the combined group. Again, our study is small with a risk of type II errors. In addition, there is an open question whether the expression of 5-HT2A receptors on the pulmonary artery smooth muscle cells is the same as on the platelets. In the present study, platelets were chosen both because they are readily available and because it has been shown that they are a reliable model for other tissues such as brain tissue with regard to 5-HT2A receptor function. The 5-HT1B and 5-HT2B receptors, which could have been at least as relevant to study as the 5-HT2A receptor [There were no differences in Brtension ,5,23, a receptor ,24,25 ar2A receptor may be of relatively low importance for the regulation of pulmonary arterial blood pressure in humans, in contrast to in rodents [The various 5HTR2A polymorphisms investigated were not related to any variables of pulmonary hemodynamics, neither in the SRI group, in the control group nor in the combined group. However, for most of these polymorphisms the frequency of the variant allele was so low that the chance to find any associations would be relatively remote. On the other hand, also for the 102 T > C polymorphism, which have a higher frequency of the variant allele, no associations were revealed. This result is consistent with the fact that the 5-HT rodents .The L allele of the 5-HTTLPR polymorphism of the SERT (5-HTT) gene has been associated with the development of pulmonary arterial hypertension in some studies ,19,20 buThe present study has a number of weaknesses that should be addressed. As already discussed a major weakness is the low number of patients included, which means that we cannot draw any conclusion regarding any potential mechanistic relationship. Moreover, it makes it unlikely that any genetic effect should be revealed. However, we nevertheless consider genetic testing as being of interest, both in order to further elucidate the complex interrelationship between drug treatment and clinical effects, and to increase the potential to explain unexpected or remarkable findings . AnotherWe consider the direct measurements of pulmonary arterial pressures by means of a pulmonary artery catheter as being a strength due to the reliability of the method. To our knowledge, no previous investigations have reported direct invasive measurements of pulmonary artery pressures in patients treated with SRIs. Although regarded as a golden standard, the pulmonary artery catheter technique is time consuming and does confer a certain risk to the patient. Therefore, to be able to include a larger number of patients, in the future pulmonary pressures could preferably be measured by less invasive methods such as echocardiography.The present study was unable to find any effect of SRI treatment on pulmonary hemodynamics. However, as minor effects cannot be completely excluded, further investigations in larger patient materials, including subjects not undergoing CABG, should be performed before any final conclusions can be drawn. Studies in a larger number of patients would also have the advantage of better utilizing the potential of genetic testing to elucidate possible gene interactions with a possible effect of SRIs on pulmonary hemodynamics.


We aimed to evaluate the multivariate association between functional microvascular variables and clinical-laboratorial-anthropometrical measurements.2), who were non-smokers, non-regular drug users, without a history of diabetes and/or hypertension, were analyzed by principal component analysis (PCA). PCA is a classical multivariate exploratory tool because it highlights common variation between variables allowing inferences about possible biological meaning of associations between them, without pre-establishing cause-effect relationships. In total, 15 variables were used for PCA: body mass index (BMI), waist circumference, systolic and diastolic blood pressure (BP), fasting plasma glucose, levels of total cholesterol, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG), insulin, C-reactive protein (CRP), and functional microvascular variables measured by nailfold videocapillaroscopy. Nailfold videocapillaroscopy was used for direct visualization of nutritive capillaries, assessing functional capillary density, red blood cell velocity (RBCV) at rest and peak after 1 min of arterial occlusion (RBCVmax), and the time taken to reach RBCVmax (TRBCVmax).Data from 189 female subjects . Fasting plasma glucose appeared to be related to principal component 4 and did not show any association with microvascular reactivity.A total of 35% of subjects had metabolic syndrome, 77% were overweight/obese, and 9.5% had impaired fasting glucose. PCA was able to recognize that functional microvascular variables and clinical-laboratorial-anthropometrical measurements had a similar variation. The first five principal components explained most of the intrinsic variation of the data. For example, principal component 1 was associated with BMI, waist circumference, systolic BP, diastolic BP, insulin, TG, CRP, and TRBCVIn non-diabetic female subjects, a multivariate scenario of associations between classic clinical variables strictly related to obesity and metabolic syndrome suggests a significant relationship between these diseases and microvascular reactivity. The microcirculation, represented by arterioles, capillaries and venules, is where blood/tissue nutrition and exchange effectively takes place. Several techniques have been proposed and used to assess microvascular reactivity in the microcirculation. Among these techniques, nailfold videocapillaroscopy is a non-invasive technique that actually visualizes capillaries, assessing skin nutritive microvascular flow and reactivity.The relationship between blood glucose and the microcirculation requires further clarification, because even in non-diabetics, insulin resistance is a significant predictor of poor outcome in patients admitted with myocardial infarction ,2. AdditThe endothelial glycocalyx is a network of membrane-bound proteoglycans and glycoproteins covering the endothelium in the luminal side. Both endothelium and plasma-derived soluble molecules integrate into this mesh. In healthy vessels glycocalyx determines vascular permeability, attenuates blood cell–vessel wall interactions, mediates shear stress sensing, enables balanced signaling, and fulfills a vasculoprotective role. However, in states of disease, experimental settings ,10 have Microvascular reactivity occurs at the level of small pre-capillary arterioles, which are considered as the main regulators of capillary reactivity, also contributing to total peripheral vascular resistance. Nailfold videocapillaroscopy is used to measure capillary variables that reflect endothelial control at pre-capillary sites. In metabolic diseases, correlations between findings with dynamic videocapillaroscopy and observed findings in target organs still need further elucidation. We have previously shown, that in response to an insulin-sensitizing agent given to metabolic syndrome normoglycemic patients, there was a concomitant improvement in skin microvascular dysfunction  and in eThe current study investigated a large number of patients, tested by dynamic nailfold videocapillaroscopy, in a sample of predominantly non-diabetic non-hypertensive obese female subjects, analyzed by principal component analysis. PCA is a multivariate exploratory approach used to identify common variation between analyzed variables, aiming to reduce the dimensionality of the data set and to detect the main source of inherent variation among investigated variables. It should be noted that the main assumption for this statistical method does not pre-establish any possible cause-effect relationship between variables. By grouping variables that behave in a similar fashion, they form a principal component, and by doing so, the researcher can suggest a biological phenomenon associated with it, and even name the principal component. Our study aimed to explore trends and associations between microvascular function and classic clinical measurements frequently used in a clinical cardiometabolic setting without pre-establishing cause-effect phenomena.2) were selected from a large age range group, 12–64 years, and classified according to body mass index (BMI) as normal weight, overweight, or obese  = 5.5±2.5%). Red blood cell velocity (RBCV) at rest and its peak after 1 min of arterial occlusion (RBCVmax), which was achieved by a pressure cuff placed around the proximal phalanx, and the time taken to reach RBCVmax (TRBCVmax) were measured with a final magnification of x680, before and during the post-occlusive reactive hyperemia response. Conceptually, functional capillary density and RBCV tested at rest, and RBCVmax and TRBCVmax assessed during post-occlusive reactive hyperemia, are considered functional variables. Time resolution for velocity measurements for the non-interlaced 30 video frames per second (fps) used, corrected for image persistence, is 0.2 s. Nailfold videocapillaroscopy is a well-validated method, and our intra-assay coefficients of variation have been previously reported ); 50% (n=20) of subjects were between 31–50 years (21% [n=40]); and 24% (n=11) of subjects were ≥51 years (24% [n=45]). Fifty-nine subjects (31.2%) were normotensive, 89 (47.1%) had prehypertension, 35 (18.5%) were at stage 1 hypertension, and 6 (3.2%) were at stage 2 but without ongoing treatment. All subjects with ≥JNC 7 stage 1 were referred to the outpatient care unit for treatment. Eighteen (9.5%) subjects had impaired fasting glucose, but all of them had a 2-h post-load glucose below 7.8 mmol/l.Table max in the same way of variation, and also a strong association among HDL-c, RBCV, RBCVmax, but in the opposite way. For principal component 2, two variables  reached the cutoff value, accounting for 16.5% of the variation. Explaining 12% of the total variation, only microvascular variables  loaded principal component 3. Unexpectedly, fasting plasma glucose appeared for the first time only in principal component 4, contributing to 8% of the variation, but without an association with any microvascular variable. For principal component 5, which explained 7% of the variation, only diastolic BP presented with a load higher than the established cutoff. One of the assumptions of this statistical method allows the designation of principal components according to what they appear to express from a biological view. Principal component 1 could be designated as the abdominal obesity and insulin resistance component, clinically expressed as metabolic syndrome, with principal component 2 as the dyslipidemic component. Principal component 3 could be designated as the microvascular component, while principal components 4 and 5 could be viewed as glycemic and pressure components, respectively. All of the analyses described above were performed excluding subjects ≤18 years. RBCVmax loading on principal component 3 lost its significance, but any other significant difference was not observed (data not shown).According to the Kaiser-Guttman method , only thp<0.001; PC2: p<0.01; PC3: p<0.01; PC5: p<0.01). According to their principal component 1 scores, chosen BMI classes could be differentiated , where normal weight subjects were more related to HDL-c, RBCV, and RBCVmax, while obese subjects were more related to higher values of variables that were composed of principal component 1 . Analysis of principal component 3 scores according to BMI classes indicated significant differences between normal weight and overweight , and also between normal weight and obesity , with no difference between subjects who were overweight and those who were obese. Normal weight subjects showed an association with higher values of functional capillary density, RBCV and RBCVmax.Using BMI as a grouping variable, we categorized our subjects as normal weight, overweight, and obese, and observed significant differences in four principal components (PC1: p<0.001), and this diagnosis was associated with higher values of variables intrinsically related to insulin resistance but also to a prolonged microvascular reactive hyperemia response, such as BMI, waist circumference, systolic BP, diastolic BP, insulin, TG, CRP and TRBCVmax).Principal component 1 was the only component able to show differences between subjects with and those without metabolic syndrome  associated with the time taken to reach peak red blood cell velocity (TRBCVmax) during the reactive hyperemia response. Prolongation of the reactive hyperemia response was also associated with increased blood pressure, insulinemia, and CRP levels in principal component 1, reassuring our previous findings in other small samples [Microvascular variables associated with clinical variables were present in two principal components, 1 and 3, with the latter expressing exclusively the microcirculation. For principal component 1, which explained most of the variance, RBCV and RBCV samples ,6. Theseper se are more important determinants of vascular function than dysglycemia. These recent studies examining macrovascular reactivity support and parallel our findings on nutritive microcirculation because our population was predominantly composed of obese female subjects with insulin resistance but without hyperglycemia.In a nondiabetic lean/overweight population, Voidonikola and co-workers  reportedOur study has some limitations. Sex specificities and their effect on vascular homeostasis should be considered. The addition of male subjects might reinforce our results, because the protective aspect of the female hormonal milieu is well-established in the cardiovascular literature, and our group was predominantly composed of fertile female subjects. The large age range in the investigated group led to differences in the prevalence of obesity/metabolic syndrome and hormonal status, which could also be viewed as a possible bias for the analysis, but the proposed statistical procedure reduced this age bias.per se appear to be more important for observed relationships.In conclusion, based on our PCA, we found that the nutritive microcirculation of non-diabetic female subjects with a wide age range and with different adiposity levels and metabolic impairment, is associated with classic clinical variables, but not with fasting plasma glucose levels. Therefore, we postulate that, in our cross-sectional study population, impaired fasting glucose is not associated with precocious microvascular dysfunction, and obesity and metabolic syndrome max: Peak red blood cell velocity; TG: Triglycerides; TRBCVmax: Time taken to reach RBCVmax.BP: Blood pressure; CRP: C-reactive protein; HDL-c: High-density lipoprotein cholesterol; LDL-c: Low-density lipoprotein cholesterol; PCA: Principal component analysis; RBCV: Red blood cell velocity; RBCVThe authors declare that they have no competing interests.DGP wrote the manuscript, analyzed the data and contributed to the discussion. RC collected the data. PAM collected the data. FLS wrote the manuscript, analyzed the data, and contributed to the discussion. EB reviewed/edited the manuscript. LGKA wrote the manuscript, analyzed the data, contributed to the discussion, and reviewed/edited the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2261/12/102/prepub


The aim of the study was to investigate the effect of red blood cell (RBC) transfusion on hemodynamic parameters including transpulmonary thermodilution (TPTD)-derived variables.We compared hemodynamic parameters obtained before and after RBC transfusion (2 RBC units) in 34 intensive care unit (ICU) patients.2) , and oxygen delivery (DO2)  compared with baseline. Cardiac output (CO) , cardiac index (CI) , and heart rate  were significantly lower following RBC transfusion while no significant change in stroke volume (SV) was observed. Mean arterial pressure (MAP)  and systemic vascular resistance index (SVRI)  significantly increased directly after RBC transfusion. Global end-diastolic volume index (GEDVI), extravascular lung water index (EVLWI), and pulmonary vascular permeability index (PVPI) did not significantly change.Directly after RBC transfusion, we observed a significant increase in hematocrit , hemoglobin , arterial oxygen content , pulmonary edema (EVLWI), and pulmonary vascular permeability (PVPI) are observed following RBC transfusion.In ICU patients, the transfusion of 2 RBC units induces a significant decrease in CO and CI because of a significant decrease in heart rate (while SV remains unchanged). Despite the decrease in CO, DO Anemia is a common finding in critically ill patients treated in the intensive care unit (ICU) . Because2), and basic hemodynamic data such as systolic and diastolic blood pressure, MAP, heart rate, and central venous pressure (CVP) were recorded. Thirty-five patients were included in the study. One patient was not included in the statistical analysis because the central venous catheter was inserted via the femoral vein thus not allowing accurate determination of ScvO2, CVP, and TPTD-based cardiac preload parameters [This was a prospective study in ICU patients receiving RBC transfusions in a German university hospital. Patients (18 years of age or older) monitored using TPTD who received 2 units of RBC concentrates for treatment of anemia not related to acute hemorrhage were eligible for study inclusion. The indication for RBC transfusion was made independently from the study by the ICU physician in charge. During the study period, usually a hemoglobin value of about 7 g/dL was used as a transfusion trigger in our ICU. According to our ICU standard operating procedures, vasoactive agents were titrated to maintain a mean arterial pressure (MAP) above 65 mmHg. In patients included in the study, TPTD measurements were performed immediately before, directly after, and 2 hours after RBC transfusion. In parallel, data regarding respiratory function , central venous oxygen saturation  and written informed consent was obtained from all patients or their legal representatives.2) was calculated as follows:Arterial oxygen content  was obtained using the formula:Oxygen delivery Cardiac index (CI), global end-diastolic volume index (GEDVI), systemic vascular resistance index (SVRI), extravascular lung water index (EVLWI), pulmonary vascular permeability index (PVPI), and index of left ventricular contractility (dPmax) were determined using single-indicator TPTD -17. TPTDt-test for paired samples and the Wilcoxon signed rank test for paired samples for normally distributed data and not normally distributed data, respectively. A p-value below a significance level of 5% (p < 0.05) indicates statistical significance.IBM SPSS Statistics 20  was used for all statistical analyses in this study. To present descriptive statistics, we calculated mean ± standard deviation for normally distributed continuous data, median and 25%-75% percentile range (i.e. interquartile range) for not normally distributed continuous data, and absolute and relative frequencies for categorical data. To compare the hemodynamic variables before and after RBC transfusion (primary endpoint) as well as before and 2 hours after RBC transfusion, we performed the Thirty-four patients who received RBC transfusions (each RBC transfusion consisting of 2 units of RBC concentrates) were included in the final analysis. The demographic and clinical characteristics of these patients are presented in Table 2, and DO2 when determined directly after and 2 hours after the transfusion , SaO2, and ScvO2 were not statistically significantly different before and after RBC transfusion.Compared with baseline, RBC transfusion resulted in a statistically significant increase in hematocrit, hemoglobin, CaOThe effects of RBC transfusion on hemodynamic variables measured directly after and 2 hours after the transfusion are presented in Table CO and CI were statistically significantly lower directly after and 2 hours after RBC transfusion compared with baseline. Since there was no statistically significant RBC transfusion-induced change in SV, the decrease in CO/CI is explainable by the significant decrease in heart rate. Whereas MAP and SVRI significantly increased directly after RBC transfusion, the TPTD-derived cardiac preload parameter GEDVI did not significantly change. Following RBC transfusion, there was no significant change in CPI and dPmax compared with baseline values. In addition, RBC transfusions did not significantly alter EVLWI or PVPI. In patients with the need for norepinephrine therapy, the vasopressor dose was lower after RBC transfusion compared with baseline (baseline: 0.07 (0.03-0.10) μg/kg/min, after RBC transfusion: 0.05 (0.02-0.08) μg/kg/min, p = 0.051).2 due to a significant increase in CaO2. Whereas MAP and SVRI significantly increased directly after RBC transfusion, there was no statistically significant change in CPI, dPmax, and the TPTD-derived cardiac preload parameter GEDVI compared with baseline values. No significant changes in parameters reflecting pulmonary edema (EVLWI) and pulmonary vascular permeability (PVPI) were observed following RBC transfusion.In this study, we evaluated the effects of RBC transfusion on advanced parameters of cardiopulmonary function obtained using TPTD in ICU patients. Following the transfusion of 2 units of RBC concentrates, CO and CI were significantly lower compared with baseline values, because RBC transfusion resulted in a significant decrease in heart rate while no statistically significant change in SV was observed. Despite the decrease in CO, we observed a significant increase in DO2 as well as in an increase of MAP and SVRI. The RBC transfusion-associated improvement of tissue oxygenation (i.e. increase in CaO2) might attenuate the anemia/hypoxemia-induced sympathoadrenal response [The finding that CO/CI are significantly lower following RBC transfusion might be explained as follows. Our results demonstrate that the increase in hemoglobin concentration following RBC transfusion results in an increase in CaOresponse  and mighIn our study, we recorded hemodynamic data before, directly after, and additionally 2 hours after RBC transfusion. Interestingly, while arterial pressure values  were statistically significantly higher when determined directly after RBC transfusion compared with baseline values but not when measured 2 hours after the transfusion, the RBC transfusion-associated effects on CO/CI were even more pronounced 2 hours after than directly after transfusion. This finding demonstrates that the observed effects on cardiac function are not only short-term effects , but are the result of complex RBC transfusion-induced changes of central hemodynamic parameters.At first glance, it is surprising that we did not observe a significant increase in the cardiac preload parameter GEDVI following transfusion of 2 RBC units. In addition, the statistically significant increase in CVP (16 ± 7 to 17 ± 7 mmHg) seems to be of very limited clinical relevance. However, patients included in the trial were in a state of isovolemic anemia, because anemia due to acute hemorrhage was an exclusion criterion in our study. Furthermore, patients included in the study had in large part been treated in the ICU for a longer time period before study inclusion (including volume resuscitation guided by advanced hemodynamic monitoring using TPTD). Since the hematocrit level markedly and significantly increased following RBC transfusion whereas cardiac preload parameters remained unchanged, we hypothesize that in our patients a part of the additional blood volume was shifted from the central circulation to capacity vessels.Considering the fact that SVRI is not a directly measured but a calculated parameter (derived from the formula SVRI = (MAP – CVP)/CI x constant), the finding that SVRI increased following RBC transfusion is a logical mathematical result associated with the observed changes in MAP, CVP and CI.2 and DO2, ScvO2 remained unchanged following RBC transfusion compared with baseline values in our study. Considering previous data [2 did not increase after RBC transfusion. However, to definitely interpret this finding, one would need to exactly know oxygen extraction (and therefore oxygen consumption) in addition to DO2 before and after RBC transfusion. Unfortunately, we are not able to calculate oxygen consumption because we did not use a pulmonary artery catheter for hemodynamic measurements in our study and therefore are unable to report mixed venous oxygen saturation (SvO2) values. Therefore, although ScvO2 might be used as a surrogate marker for SvO2, we are not able to draw definite conclusions about oxygen extraction and the finding that ScvO2 was not influenced by RBC transfusion.Despite the significant increase in CaOous data , one mig2 and a significant decrease in heart rate. Furthermore, DO2 also markedly increased following RBC transfusion in their study. However, in contrast to our data, this increase in DO2 was not statistically significant. In addition, contrary to our findings (demonstrating a RBC transfusion-induced decrease in CO and CI), CO and CI were not significantly different after transfusion of RBC in the study by Gramm and colleagues. This might be due to the fact that they solely included septic patients in whom a hyperdynamic hemodynamic state (with high CO) can regularly be observed.In a previous study , Gramm eTransfusion-related acute lung injury (TRALI) has been described as an important and severe adverse effect of RBC transfusion in critically ill patients -24. In TFor TPTD measurements, we used the PiCCO technology in our study. This technology for advanced hemodynamic monitoring allows the determination of various cardiopulmonary parameters  based on the principles of TPTD and pulse contour analysis -17,25. TThe results of our study contribute to the understanding of the effects of RBC transfusion on hemodynamic parameters. However, as mentioned before, although we used an advanced hemodynamic monitoring system for study measurements, our approach does not allow drawing definite conclusions about the impact of RBC transfusion on oxygen extraction and oxygen transport. Therefore, larger studies on this subject allowing the determination of oxygen extraction calculated using oxygen consumption are needed in the future to learn more about the impact of RBC transfusion on oxygen transport. More data in this area are needed, to have a more differentiated view on transfusion triggers in critically ill patients.The low number of patients studied and the fact that we performed our study in a single ICU, are limitations of our study. Furthermore, the use of vasoactive drugs during RBC transfusion and study measurements might have influenced the results regarding CO.2 significantly increases because of a significant increase in CaO2. In addition, RBC transfusion results in a significant increase in MAP and SVRI. No significant changes in TPTD-parameters reflecting cardiac preload (GEDVI), pulmonary edema (EVLWI), and pulmonary vascular permeability (PVPI) are observed following RBC transfusion.In ICU patients, transfusion of 2 RBC units induces a significant decrease in CO and CI because of a significant decrease in heart rate (while SV remains unchanged). Despite the decrease in CO, DO– Anemia is a common finding in intensive care unit patients and is usually treated with red blood cell transfusion. There are limited data on the impact of red blood cell transfusion on advanced hemodynamic parameters reflecting cardiopulmonary function.– According to our results, in ICU patients, the transfusion of 2 red blood cell units induces a significant decrease in cardiac output and cardiac index because of a significant decrease in heart rate (while stroke volume remains unchanged). In addition, red blood cell transfusion results in a significant increase in mean arterial pressure and systemic vascular resistance index.– Despite the decrease in cardiac output, oxygen delivery significantly increases because of a significant increase in arterial oxygen content.– No significant changes in transpulmonary thermodilution-derived parameters reflecting cardiac preload, pulmonary edema, and pulmonary vascular permeability are observed following red blood cell transfusion.2: Arterial oxygen content; CI: Cardiac index; CO: Cardiac output; CPI: Cardiac power index; CVP: Central venous pressure; DO2: Oxygen delivery; dPmax: Index of left ventricular contractility; EVLWI: Extravascular lung water index; GEDVI: Global end-diastolic volume index; Hb: Hemoglobin concentration; ICU: Intensive care unit; MAP: Mean arterial pressure; PaCO2: Arterial partial pressure of carbon dioxide; PaO2: Arterial partial pressure of oxygen; PVPI: Pulmonary vascular permeability index; RBC: Red blood cell; SaO2: Arterial oxygen saturation; ScvO2: Central venous oxygen saturation; SV: Stroke volume; SvO2: Mixed venous oxygen saturation; SVRI: Systemic vascular resistance index; TPTD: Transpulmonary thermodilution; TRALI: Transfusion-related acute lung injury.CaOBernd Saugel and Wolfgang Huber collaborate with Pulsion Medical Systems  as members of the Medical Advisory Board. All other authors declare that they have no competing interests.BS, VP, RMS, and WH conceived and designed the study. BS, MK, VP, and CS were responsible for acquisition of data. BS, AH, ASM, and WH performed the statistical analyses. BS, MK, VP, CS, ASM, MM, RMS, and WH were responsible for data analysis and interpretation. BS, AH, VP, CS, ASM, MM, and WH drafted the manuscript. RMS critically revised the manuscript for important intellectual content. RMS and WH supervised the study. All authors read and approved the final version of the manuscript.


Diabetic Peripheral Neuropathy is one of the most prevalent complications of diabetes mellitus. The development and progression of such complications are responsible for much of the morbidity and mortality. The purpose of this study was to evaluate the effectiveness of Semmes–Weinstein monofilament ten gram in 3, 4, eight and ten points in the screening of diabetic peripheral neuropathy in patients with diabetes mellitus.In a descriptive correlational design, 150 patients with diabetes mellitus were selected using convenience sampling. All patients were evaluated for sensory neuropathy using ten gram Semmes-Weinstein Monofilaments and questionnaire on neuropathy symptoms. In the next phase, nerve conduction velocity was examined. The most common subjective symptoms were paresthesia of both feet, pain in feet, burning sensation in the extremities and numbness in the extremities.The results showed that the sensitivity of Monofilament in three and four points were 35.9 to 53.8 present and 38.5 to 51.3 percent respectively. Specificity of Monofilament the same points, were 73.9 to 84.7 and 73 to 87.4 percent respectively. Monofilament sensitivity at eight and ten points were 38.5 to 61.5 and 64.1 to 30.8 percent respectively. Also, specificity of the same points were 77.5 to 95.5 and 64 to 89.2 percent respectively. It was revealed that the difference sensitivity and specificity of Monofilament in three and four points with sensitivity and specificity in eight and ten point is not statistically significant.This study showed that Semmes-Weinstein monofilament can easily use as a simple and inexpensive device for screening. Since increasing the number of points it was not significantly difference. Therefore, we suggest that screening for diabetic peripheral neuropathy, especially in large populations to avoid wasting time on Monofilament application, areas like three or four points eight and ten points could be used. Diabetes is the most common metabolic disease worldwide. IDF and WHO reported increasing incidence all around the world especially in developing countries . PrevaleThese complications, especially ulcer and amputation, affect the quality of patients’ life, which in turn leads to repeated hospitalizations and increased health care costs . For insSeveral devices are used to track the performance of protective sensation of the foot in diabetic patients. Monofilaments, along with other methods such as evaluation of pain sensation, sense of vibration, temperature sense, and deep reflexes are considered the common methods for the screening of DPN . Nerve cNurses, by using a monofilament as screening method, also can provide the necessary training to prevent foot ulcer and amputation  to those at risk of neuropathy ,17. In oClinical care guidelines have recommended that annual screening for peripheral neuropathy occur in all patients with diabetes, as part of the routine evaluation of patients in terms of complications . The senIn the international study this test was conducted on 10 and 15 points, and the results have been different. Since in the most studies, a 10 g monofilament has been used often for screening, and no study still has been conducted for comparing 10 g monofilament in different points carefully, this study was designed with the following objectives: The first aim of our study was to answer the question that whether increasing the number of points to use in screening monofilament neuropathy can be accompanied with high sensitivity? The second objective was to compare the sensitivity and specificity of monofilament with the Modified neuropathy disability score.A quasi-experimental design was used to conduct this study. This research was conducted from 2010 to 2011 with 150 patients suffering from type II, DM referred to a Diabetic Clinic affiliated to a teaching hospital in Ahvaz, Iran.α = 0.05, β = 0.2, p1 = 0.86, p2 = 0.96 adopted from other studies ..31].The data analysis was performed using the SPSS software Ver.16. The Sensitivity and specificity of the SWMT were measured. The data were presented as means and standard deviations, and percentiles.glibenclamide and metformin  and 103 females (68.7%). The average age of the patients was 55.71 ± 8.95 years and the mean of disease duration was 7.7 ± 6.1 years. The mean fasting blood glucose, the mean HbA1c, the mean cholesterol, the mean triglycerides, the mean HDL Blood, the mean LDL Blood level, the mean BMI and the mean weight in patients were 169.92 ± 72.66, 8.26 ± 3.96, 182.31 ± 44.10, 127.49 ± 54.87, 47.21 ± 12.24, 100.21 ± 34.09, 27.45 ± 4.85, and 55.35 ± 8.99, respectively. All patients were under treatment with oral medication. Drug regimen for most patients was The results showed that the majority of patients (75. 34%) have had HbA1c levels greater than 7%. It is shown that these patients have had a poor control over their diabetes. Among the clinical manifestations of neuropathy, paresthesia (72%), pain at feet (71.3%), feeling of pins and needles at feet tips (71.3%), numbness at terminals (63.3%), pain in hands (61.3%), and coldness at feet (50.7%) had the highest prevalence among the patients. Totally, through the examination of symptoms, 93 patients were healthy and without neuropathy and 57 individuals (38%) had neuropathy.Testing with the 10 g monofilament was assessed according to different cut-off points for positivity Table . (a) FroThe procedure for 4 points, 8 points, and 10 points were used in each plantar foot. So that a minimum one points out of 8 points, at least two points out of 8 points, and 4 points out of 8 points at numb have been reported. At least, one point of 16 points, two points out of 16 points, eight points out of 16 points at numb have been reported. At least, one point out of 20 points, two points out of 20 points, 10 points out of 20 points at numb have been reported Tables , 4 and 5We also compared the results of monofilament with the improved sensitivity and specificity of the improved neuropathy criterion and the tuning fork tests Table . PatientResults of the improved neuropathy criterion showed that of the 150 patients with neuropathy participating in the study, 138 patients have acquired scores equal to or greater than 6, and it shows that according to this criterion, 92% of our patients had been moderate to severe symptoms of neuropathy.Moreover, the tuning fork testing that is part of NDS criterion was evaluated separately. Thus, the lack of the tuning fork vibration sense on one of the big toes was used as a positive point. Sensitivity and specificity of tuning fork was alone at these points 84.6% and 43.2% respectively. The sensitivity and specificity of both tests were greater than monofilament.The use of this test in our study showed that when factors such as cost and ease of use are concerned, then 10-g Semmes-Weinstein monofilament are effective for detection and screening of the foot protective sense reduction about the diabetic foot. In this study, we applied Semmes-Weinstein monofilament in 3, 4, 8 and 10 points per the sole of the foot. If we look at the results of monofilament in these points, we see that the sensitivity of monofilaments was in the range of 30.8%– 64.1%. This relatively low sensitivity implies that these abnormal areas and the numb points only can be diagnosed in very severe neuropathies. Also, according to the obtained results, we see that sensitivity and specificity of monofilament in 3points and 4points have not statistically significant difference with sensitivity and specificity in the 8 points and 10 points. In other words, with increasing the number of studied points, the monofilament sensitivity has not been increased. Therefore, we recommend that physicians or nurses use from fewer points like 3 points and 4points to screen the patients with diabetes, and do not spend their time to use monofilament in more points.In this study, the sensitivity of monofilament in 3 points and specificity of this test were (38.5%–51.3%) and (73%–87.4%) respectively. Kamei in his study, reported sensitivity and sensitivity of 10-g Semmes-Weinstein monofilament in 3 points, 5%–22.5% and 88.1%–97.6% respectively  that comMoreover, in this study, the sensitivity and specificity of monofilament in the 4 points were 38.5%–51.3% and 73%–87.4% respectively. Miranda-Palma et al., reported the range of sensitivity and specificity of Semmes-Weinstein 10 g monofilament at four sites, from 65% to 86%, and 58% to 71%, respectively . In thisAlthough the use of monofilament has been started since 1995, but the number of points that must be considered is still under study. In our study, the prevalence of diabetic neuropathy on the basis of a positive test 10–g Semmes-Weinstein monofilament is the 9.33%–24% . This fiNevertheless, the aim of our study was the use of monofilament as a screening measure of peripheral neuropathy, while they used monofilament to track down and detect the numb foot to prevent lower limb amputation. Furthermore, their study differs from ours, because they compared the sensitivity and specificity of 10-g monofilament with vibration test as the gold test while we used nerve conduction tests (NCV) as the gold test.The above examples demonstrate that subtle changes in abnormal response to monofilament can cause differences in the prevalence of numbness in feet between 3.4%–29%. On the other hand, for simple things like monofilament, small changes in the force imposed to monofilament can lead to misleading results and unusual effects. For this reason, there is a disagreement for its use in distinctive countries which it can lead to an ambiguity in epidemiological researches and to estimate the need in the health care ,31,33. MIn this study, we used a questionnaire for subjective signs in order to investigate the neuropathy. Results of Testing of the signs showed that 93 persons were healthy and without signs of neuropathy, and 57 persons (38%) were with neuropathy. Pain and tingling sensation had the most prevalence among the clinical signs of paresthesia. In 78.7% of the patients, knee reflexes diminished or disappeared; and in 64% of patients, vibration sense was impaired. Our content can be also confirmed by Kamei’ study, where 51.2% of patients suffered from the pain, numbness, and paresthesia in both legs. In 56.1% of the patients, knee reflexes were reduced or eliminated; and vibration test in 36.6% of the patients was impaired. In this same study, the majority of patients had muscle cramps, numbness in the extremities, and the moderate to severe pain .Monofilament test cannot be favorably compared with other methods. The results of a comparison between monofilament tests with standard NDS showed that the sensitivity and specificity of NDS criterion are high. While the results of Miranda Palma’s study showed that the sensitivity of monofilament is higher than NDS, but its specificity was lower than in the standard . TherefoAlthough other studies have used the NDS as the accurate and useful method for investigating the environmental sense, but reasons to use the monofilament method are to be easy, to be available, and to be cheap ,9,24,32.Associated with glycemic control, HbA1c and fasting blood-glucose levels in this study showed that most patients have poor blood-glucose control and were not able to maintain normal blood sugar range themselves. Therefore, this study can provide evidence for physicians, nurses, and healthcare policy makers, so they can make changes in the current health system, including to provide the necessary and sufficient training to patients, and to follow the screening of the patients more seriously in both hospital wards and outpatient clinics.Moreover, we investigated screening for diabetic peripheral neuropathy in our study, and concluded that none of the patients involved in the study were not studied in terms of diabetic peripheral neuropathy and its complications. In other words, the present study is the first study to screen the patient with diabetes. These findings show that the screening of diabetic peripheral neuropathy is poor in Ahvaz that should be improved.Overall, by increasing the number of points for neuropathy screening, the sensitivity monofilament did not increase. In other words, the sensitivity of monofilament in 3 and 4 points is almost similar to it in 8 and 10 points.The use of monofilament solely or in combination with NDS or other reflex tests for neuropathy screening method is an easy and accessible method; and by early detection, it can prevent complications that include leg ulcers and amputation in patients with diabetes. The Testing also seems to be important in this context, and it cannot be released from it along with taking a profile.The authors declare that they have no competing interests.SHB: Study design, data collection/analysis, drafting of manuscript, supervision. KZ: administrative/technical/material support, critical revisions for important intellectual content. HBSH: administrative/technical/material support, supervision. ML: Study conception, data analysis, and supervision. All authors read and approved the final manuscript.


Associations between ambient temperature and blood pressure have been demonstrated in countries where the temperature varies between the seasons. This phenomenon has been overlooked in blood pressure surveys in sub-Saharan Africa. We assessed the effect of ambient temperature on blood pressure in an adult population in a West African country.A cross-sectional survey was carried out on a rural Ghanaian population, investigating the effect of ambient temperature on blood pressure in 574 randomly sampled adults aged between 18 and 65 years.p < 0.019) and diastolic blood pressure (DBP) (p < 0.036). SBP fell by 5 mmHg per 10ºC rise in ambient temperature.There was a significant inverse relationship between ambient temperature and systolic (SBP) (Higher ambient temperatures are associated with lower blood pressures. To enhance comparability of data from epidemiological surveys, ambient temperature should be recorded for each blood pressure reading and findings standardised to a fixed ambient temperature. Blood pressures have been found to be higher in winter and lower in summer.Despite the extent of evidence on the ambient temperature– blood pressure phenomenon, not much attention has been paid to its implications for clinical practice, and quantitative formulations have not been developed to correct for this bias. There are currently no data published on the relationship between ambient temperature and blood pressure in sub-Saharan West African countries, where the seasons are classified into two – the rainy and dry seasons. Daily maximum temperatures during the dry season range between 38 and 45ºC and those for the rainy season are between 20 and 26ºC.The aim of this study, part of a cross-sectional blood pressure survey, was to study the influence of ambient temperature on blood pressure in a rural West African adult population.The study was conducted in the Kassena–Nankana District (KND) of northern Ghana. Ghana is a tropical country located on West Africa’s Gulf of Guinea, a few degrees north of the Equator, with a total area of 238 540 km2. It has an estimated population of 19.7 million, a gross domestic product (GDP) of 7.4 billion US dollars and a per capita GDP of 412 US dollars.KND is one of the eight districts in the northernmost part of Ghana and Navrongo is its commercial and political capital. It is a relatively flat country with an area of 1 675 km2, which is wholly in the sub-sahelian woodland of West Africa. The vegetation is guinea savannah, which is characterised by short scattered trees and a more or less continuous carpet of grasses. The mildly cool rainy season extends from April to September and the prolonged and intensely hot, dry season is from October to March. Rainfall averages from 850 to 950 mm per year, with the peak occurring in August. Daily mean temperatures range between an average minimum of 20ºC in the rainy season and an average maximum of 40ºC in the dry season. In the dry season, early mornings are usually cool and the afternoons commonly hot with daily maximum temperatures going as high as 45ºC.This was part of a cross-sectional survey to determine the blood pressure levels in a rural West African population. A random sample of 600 participants was drawn from a population register, regularly updated by the Navrongo Demographic Surveillance System (NDSS), which is owned by the Navrongo Health Research Centre, a field station of the Health Research Unit of the Ghana Health Service. NDSS is a continuous population registration system that assesses the demographic dynamics of the entire population of the Kassena–Nankana district. Every 90 days, all compounds in the district are visited to update vital events such as births, deaths, pregnancy, marriages and migration in and out of the district.Blood pressure, anthropometric, time of blood pressure and room temperature measurements were taken in 574 adult males and females aged between 18 and 65 years, resident in the study area and who agreed to be part of the study. Response rate was 95.7% with 207 males and 367 females completing the study protocol. The imbalance between the genders in the random sample drawn was due to the fact that females constitute a larger percentage of the population. The 26 non-respondents, all males, were either busy on their farms or not interested in participating. Fieldwork was carried out in the KND from February to April 2007, the period when morning temperatures are low and daily temperatures reach their maximum.Ethical approval was obtained from the local Institutional Review Board of the Navrongo Health Research Centre, Navrongo, Ghana (reference: NHRC 061). The traditional chiefs, community leaders, political and opinion leaders were approached prior to commencement of fieldwork, and community meetings were held to explain the purpose of the whole study. Individual affirmations of informed consent were obtained from residents willing to participate, using informed consent forms. The consent forms were signed by those who were literate and marked with a left thumbprint for those who were not.Five fieldworkers and a supervisor with prior experience and training in epidemiological surveys of this nature were recruited and retrained in the techniques of questionnaire administration, and anthropometric and blood pressure measurements. The study team were all locals of the study area and were fluent in the local languages. Before the start of the fieldwork, each of the techniques and instruments was tested on a small sample of the population and shown to be practicable, sufficiently reliable and valid.Data were collected by interview using a simple structured questionnaire, and measurements were recorded on a standard form. For date of birth, an estimated date was assigned to those who were unable to give their exact dates of birth, using the seasons, festivals and some historical indicators as guides. June 30 was allocated if the exact date and month could not be decided upon.Blood pressure measurements followed administration of the questionnaire and anthropometric measurements. Reliable automatic blood pressure devices (Omron MX3 plus), which were validated against the reference method of sphygmomanometry ,Two weeks after the main survey, a sub-sample, randomly sampled from the study participants, were invited to have repeat BP and temperature measurements taken in the morning between 06:00 and 10:00 when temperatures were at their minimum, and again in the afternoon between 13:00 and 15:00 when the temperatures were at their maximum. Thirty-seven participants volunteered for the repeat measurements. In the repeaters, BPs and time-of-day measurements were taken randomly. Following the WHO MONICA methodology,To determine BP changes with ambient temperature, readings were grouped based on the temperatures at the time of blood pressure measurements in the morning, and in the afternoon for the follow-up survey. Two temperature categories were used. Category 1 consisted of BP readings with an ambient temperature range of 28 to 34ºC and category 2 consisted of readings with temperatures ranging from 39 to 43ºC. BP readings for the two temperature groups were averaged and compared.P-values < 0.05 (two-sided) were considered statistically significant. All results were given as mean (standard deviation) unless indicated otherwise. All statistical analyses were performed using the Statistical Package for Social Sciences (SPSS) version 15 for MS WINDOWS.Pearson’s linear correlation was performed to determine the dose–response relationship between ambient temperature and BP readings. To further explore the association between temperature and BP, bivariate regression analyses were used. To assess the independent association of ambient temperature with BP variability, systolic and diastolic blood pressure were regressed on ambient temperature in separate multiple linear regression models, including and excluding age, gender, body mass index, waist circumference and time of blood pressure measurement. The 574 participants ranged in age from 18 to 65 years. Mean age was 37.8 (14.0) years with 36.1% being males and 63.9% females. Mean age of males was 36 (14) years and that of females was 39 (14) years. The sub-sample of 37 participants ranged in age from 18 to 65 years. Mean age was 38.4 (14.8) years.For the follow-up survey, at morning temperatures of between 28 and 34ºC, mean SBP and DBP were 123.1 (18.4) and 71.9 (13.0) mmHg, respectively. At afternoon temperatures between 39 and 43ºC, mean SBP and DBP were 120.9 (19.4) and 70.6 (12.1) mmHg, respectively. There was a moderate but relevant difference in mean systolic and diastolic BPs for the two ambient temperature categories.r = –0.1, p = 0.02).Mean correlation coefficients for SBP and DBP against temperature are displayed in p = 0.02, 95% confidence interval: –1.19 to –0.11). Linear regression analysis showed that SBP was significantly and inversely related to ambient temperature  opposed to the random-zero sphygmomanometer recommended by the WHO MONICA protocolAwareness of the phenomenon that there is a correlation between BP and ambient temperature is quite important, considering the fact that high blood pressures are recorded during low ambient temperatures. The significant differences in blood pressure at different ambient temperatures may have some implications, such as under- or overestimating blood pressure levels in various populations.