Effects of spironolactone in spontaneously hypertensive adult rats subjected to high salt intake

OBJECTIVE: To evaluate the effect of spironolactone on ventricular stiffness in spontaneously hypertensive adult rats subjected to high salt intake. INTRODUCTION: High salt intake leads to cardiac hypertrophy, collagen accumulation and diastolic dysfunction. These effects are partially mediated by cardiac activation of the renin-angiotensin-aldosterone system. METHODS: Male spontaneously hypertensive rats (SHRs, 32 weeks) received drinking water (SHR), a 1% NaCl solution (SHR-Salt), or a 1% NaCl solution with a daily subcutaneous injection of spironolactone (80 mg.kg-1) (SHRSalt- S). Age-matched normotensive Wistar rats were used as a control. Eight weeks later, the animals were anesthetized and catheterized to evaluate left ventricular and arterial blood pressure. After cardiac arrest, a doublelumen catheter was inserted into the left ventricle through the aorta to obtain in situ left ventricular pressurevolume curves. RESULTS: The blood pressures of all the SHR groups were similar to each other but were different from the normotensive controls (Wistar = 109±2; SHR = 118±2; SHR-Salt = 117±2; SHR-Salt-S = 116±2 mmHg; P<0.05). The cardiac hypertrophy observed in the SHR was enhanced by salt overload and abated by spironolactone (Wistar = 2.90±0.06; SHR = 3.44±0.07; SHR-Salt = 3.68±0.07; SHR-Salt-S = 3.46±0.05 mg/g; P<0.05). Myocardial relaxation, as evaluated by left ventricular dP/dt, was impaired by salt overload and improved by spironolactone (Wistar = -3698±92; SHR = -3729±125; SHR-Salt = -3342±80; SHR-Salt-S = -3647±104 mmHg/s; P<0.05). Ventricular stiffness was not altered by salt overload, but spironolactone treatment reduced the ventricular stiffness to levels observed in the normotensive controls (Wistar = 1.40±0.04; SHR = 1.60±0.05; SHR-Salt = 1.67±0.12; SHR-Salt- S = 1.45±0.03 mmHg/ml; P<0.05). CONCLUSION: Spironolactone reduces left ventricular hypertrophy secondary to high salt intake and ventricular stiffness in adult SHRs

Design of a clock and data recovery circuit in 65 nm technology

As semiconductor fabrication technology develops, the demand for higher transmission data rates constantly increases; thus there is an urgent need for a power-efficient, robust and broad bandwidth chip-to-chip communication method. A lot of work has been done to address this issue as researchers strive for more integrated inter-IC communication technology with CMOS. A high-speed serial link (HSSL) can help meet this goal. The clock and data recovery circuit (CDR) is a critical component of the HSSL. CDR is built on the receiver end of the link after proper equalization. Its purpose is to extract clock signal which is not transmitted from the driver end and to use the extracted clock signal to sample the incoming data stream with optimal timing. In this thesis, the working mechanism of the CDR is described. A CDR consists of a phase detector, a charge pump, a loop filter and a voltage-controlled oscillator. This thesis includes an overview of all the building blocks of a PLL-based CDR, derivation of the mathematical formulations of the negative feedback loop, and a report on closed loop behavioral modeling of the entire CDR and implemented CDR building blocks at transistor level with TSMC 65 nm technology PDK with a 6.4 Gbps data rate. Also, this thesis provides a detailed noise analysis of the CDR. Lastly, some future work and possible design improvements are proposed

Gender-specific determinants of blood pressure elevation in Angolan adults

Background: Hypertension affects African–American adults more than any other ethnic group in the US. However, some of the black populations living outside Africa are well adapted to food and lifestyle. We aimed to describe the clinical characteristics underlying the gender-specific determinants of BP and the risk of hypertension in public-sector workers living in Angola. Materials and methods: 609 volunteers (48% men) were included in this cross-sectional and descriptive study. Demographic, socioeconomic and life style data were collected during an interview. Systolic BP (SBP) and diastolic BP (DBP) were measured, along with some anthropometric and clinical variables. Results: The prevalence of hypertension is 45.2% without difference between genders. Obesity was more prevalent in women (29.2% vs. 8.9%, p < 0.05). The age-related increment in SBP is higher in women (14.2 ± 1.1 vs 9.5 ± 1.3 mmHg/decade, p < 0.05). In men, age, BMI, cholesterol and LDLc/HDLc explained 21, 4, 2.5 and 2.9% of SBP variability, respectively. In women, age, BMI and HC explain 27, 2 and 1% of SBP variability, respectively. The risk for hypertension is 5 × high among men aged ≥45 years, and 3.5× in those having BMI ≥25. Women aged 45 years or older have 8 × risk of hypertension and 2× the risk by having BMI ≥25. Conclusions: We found that advanced age (≥45) and overweight/obesity (BMI ≥25) are the main risk factors for hypertension in adults from Angola. However, our data suggest that age and BMI may have different influence on increasing BP in men and women

Lipid disorders among Black Africans non-users of lipid-lowering medication

ABSTRACT Objective: Angola is a sub-Saharan African country where the population has scarce access to lipidlowering medication. We sought to determine the frequency of lipid disorders among Angolan nonusers of lipid-lowering medication. Material and methods: A cross-sectional descriptive study was carried out in a sample of 604 workers from the public sector. Blood pressure and anthropometric data were measured along with biochemical parameters including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). LDL-C to HDL-C ratio (LDL-C/HDL-C) was obtained from LDL-C and HDL-C levels. Results: High frequencies of elevated blood pressure (44.8%), metabolic syndrome (20.2%), increased TC (39.2%) and increased LDL-C (19.3%) were found. Low HDL-C was more frequent in women (62.4% vs. 36.1%, p < 0.001). Isolated hypercholesterolemia was more frequent in men (9.6% vs. 2.5%, p < 0.001). Among men TC, TG, LDL-C and LDL-C/HDL-C ratio were higher and HDL-C was lower in obese than in low-weight and normal-weight participants. Among women TC, TG, LDL-C and LDL-C/HDL-C ratio were higher in obese than in normal-weight participants. Significant linear trend of increasing TC and LDL-C levels as age increased was detected for both genders (p for trend < 0.05). Conclusion: The results of our study showed a high frequency of lipid disorders in Angolan non-users of lipid-lowering medication

Global distributions of age- and sex-related arterial stiffness : systematic review and meta-analysis of 167 studies with 509,743 participants

Background Arterial stiffening is central to the vascular ageing process and a powerful predictor and cause of diverse vascular pathologies and mortality. We investigated age and sex trajectories, regional differences, and global reference values of arterial stiffness as assessed by pulse wave velocity (PWV). Methods Measurements of brachial-ankle or carotid-femoral PWV (baPWV or cfPWV) in generally healthy participants published in three electronic databases between database inception and August 24th, 2020 were included, either as individual participant-level or summary data received from collaborators (n = 248,196) or by extraction from published reports (n = 274,629). Quality was appraised using the Joanna Briggs Instrument. Variation in PWV was estimated using mixed-effects meta-regression and Generalized Additive Models for Location, Scale, and Shape. Findings The search yielded 8920 studies, and 167 studies with 509,743 participants from 34 countries were included. PWV depended on age, sex, and country. Global age-standardised means were 12.5 m/s (95% confidence interval: 12.1–12.8 m/s) for baPWV and 7.45 m/s (95% CI: 7.11–7.79 m/s) for cfPWV. Males had higher global levels than females of 0.77 m/s for baPWV (95% CI: 0.75–0.78 m/s) and 0.35 m/s for cfPWV (95% CI: 0.33–0.37 m/s), but sex differences in baPWV diminished with advancing age. Compared to Europe, baPWV was substantially higher in the Asian region (+1.83 m/s, P = 0.0014), whereas cfPWV was higher in the African region (+0.41 m/s, P < 0.0001) and differed more by country (highest in Poland, Russia, Iceland, France, and China; lowest in Spain, Belgium, Canada, Finland, and Argentina). High vs. other country income was associated with lower baPWV (−0.55 m/s, P = 0.048) and cfPWV (−0.41 m/s, P < 0.0001). Interpretation China and other Asian countries featured high PWV, which by known associations with central blood pressure and pulse pressure may partly explain higher Asian risk for intracerebral haemorrhage and small vessel stroke. Reference values provided may facilitate use of PWV as a marker of vascular ageing, for prediction of vascular risk and death, and for designing future therapeutic interventions. Funding This study was supported by the excellence initiative VASCage funded by the Austrian Research Promotion Agency, by the National Science Foundation of China, and the Science and Technology Planning Project of Hunan Province. Detailed funding information is provided as part of the Acknowledgments after the main text