Low dialysate potassium and central arterial pressure waveform

Background

Cardiovascular mortality is high in hemodialysis (HD) patients. Early arterial pressure wave reflections predict mortality in HD patients, and HD acutely improves the central pressure waveform. Potassium (K) plays a crucial role in cardiac electrophysiology, and patients with end-stage kidney disease depend on HD for neutral K balance. We aimed to study the impact of dialysate K concentrations on central arterial pressure waveform.

Methods

Thirty-three chronic HD patients were studied before and after a HD session, and the prescribed dialysate K concentration was recorded. In a subset of 23 patients without arrhythmias, pulse wave analysis was performed on radial arteries. Nine patients had dialysate K set to 1 mmol/L (group 1), and 14 patients had K set to 2 or 3 mmol/L (group 2). Augmentation index (AIx), defined as difference between the second and first systolic peak divided by central pulse pressure, was used as a measure of arterial stiffness.

Results

HD reduced the AIx in group 1 only (p = 0.0005). Likewise, central systolic pressure was reduced in group 1 only (p = 0.006). The relative reduction of AIx post-HD was significantly higher in group 1 compared with group 2 (p < 0.0001). The association between low dialysate K and AIx reduction remained statistically significant after adjustment for variables including the change in central and peripheral systolic pressure and mean arterial pressure.

Conclusion

Low dialysate K is strongly and independently associated with the acute improvement of AIx.     

An antioxidant tetrapeptide UPF1 in rats has a neuroprotective effect in transient global brain ischemia

Different glutathione analogues have potential to maintain or increase tissue glutathione level and to scavenge the reactive oxygen species. We designed and synthesized a novel non-toxic glutathione analogue, named UPF1, which possessed 60-fold higher hydroxyl radical scavenger efficiency in vitro, compared with glutathione itself, and investigated the effects of UPF1 on a four-vessel occlusion model of rats. The UPF1 was administered via the jugular vein in two separate experiments at two time points: 20 min before global brain ischemia and immediately before reperfusion. In both cases the number of pyramidal cells surviving in the subfield of CA1 at the dorsal hippocampus in the UPF1-treated groups of rats was twice as high as in the vehicle group.     

The prevalence of chlamydial infection in Estonia: a population-based survey

The aim of this study was to estimate the prevalence of Chlamydia trachomatis infection among Estonian men and women by a cross-sectional study based on the screening of a probability sample of the residents of Tartu using participant-collected, mail-delivered testing for C. trachomatis complemented with the self-administered questionnaire. Full participation as defined by returning both the questionnaire and specimen was 34% (n = 479; 95% confidence interval [CI] 32-37%). Study participation was 40% (n = 560; 95% CI 37-43%) for subjects returning either or both the study questionnaire and specimen. After weighing the population distribution, the prevalence estimate for the age group of 18-35 years was 5.4% (95% CI 3.0-7.5%), 6.9% (95% CI 3.6-10.3%) among women and 2.7% (95% CI 0.3-5.0%) among men. The number of sexual partners in the past 12 months was the strongest predictor of infection.     

Clear differences in adiponectin level and glutathione redox status revealed in obese and normal-weight patients with psoriasis

Background Several studies have shown increased prevalence of obesity in patients with psoriasis. Objectives To characterize both inflammatory‐ and oxidative stress‐related differences between obese patients with psoriasis (OPP) and normal‐weight patients with psoriasis (NWPP). Methods The plasma concentrations of adiponectin and interleukin (IL)‐6 were analysed by quantitative sandwich enzyme immunoassay technique in 10 patients with a body mass index (BMI) < 25 and 12 patients with a BMI > 30. Total glutathione and oxidized glutathione levels were measured spectrophotometrically. Results Plasma concentration of adiponectin in NWPP was more than twice the level in healthy normal‐weight controls (P < 0·001), while such an elevation did not occur in OPP. OPP were characterized by a significantly increased IL‐6 level, which correlated negatively with the adiponectin level (r = ?0·85, P < 0·001). The glutathione redox status, which was also inversely correlated with the adiponectin level (r = ?0·63, P < 0·05), was associated with significantly increased oxidative stress in the OPP compared with the NWPP or controls. Conclusions Obesity in patients with psoriasis is associated with both decreased plasma levels of protective adiponectin compared with NWPP, and enhanced systemic inflammation and oxidative stress. These findings are in concordance with high prevalence of diseases related to lower adiponectin levels among psoriasis patients.     

Breathing patterns during progressive incremental cycle and treadmill exercise are different

Perceived breathlessness at comparable minute ventilation (V_E) is higher with cycling than with running. Different use of the upper extremities and chest wall may influence the breathing pattern. It was hypothetized that the relationship between tidal volume (V_T) and V_E throughout progressive incremental exercise is different with the two modes of exercise. Twelve well trained subjects (seven men) 20–25 years had incremental maximal exercise tests on a treadmill and a cycle ergometer on different days in random order. Heart rate, respiratory gases, V_E and V_T were measured on a computerized exercise testing system, and data were averaged over 20 s periods. The V_E?V_T relationship was characterized by maximum V_T, V_T at a V_E of 30 l min^?1 (V_T30), the Hey plot and by a least squares quadratic regression model. The increase in V_T by V_E was steeper and V_T30 was higher with cycling compared to running. V_Tmax was not different, but was achieved at a lower V_E with cycling. Breathing strategies are different with running and cycling in young well trained subjects, and exercise mode must be accounted for in normative studies of breathing pattern.     

Inverse relations of serum phosphatidylcholines and lysophosphatidylcholines with vascular damage and heart rate in patients with atherosclerosis

Background and aims

The rapidly growing discipline of lipidomics allows the study of a wide spectrum of lipid species in body fluids and provides new insights into the pathogenesis of cardiovascular disease. We investigated serum phosphatidylcholine (PC) and lysophosphatidylcholine (lysoPC) species in relation to arterial stiffness, hemodynamics, and endothelial dysfunction in symptomatic patients with atherosclerosis and in healthy controls.

Augmentation index and carotid intima-media thickness are differently related to age, C-reactive protein and oxidized low-density lipoprotein

OBJECTIVE: Ageing, plasma circulating C-reactive protein (CRP), oxidized low-density lipoprotein (OxLDL) and homocysteine (Hcy) are associated with atherosclerosis. The aim of this study was to evaluate the relationship between age, inflammatory and oxidative stress-related markers with functional and structural changes of the arteries in asymptomatic persons. METHODS: CRP, OxLDL and Hcy were measured in 175 clinically healthy subjects, aged 40-70 years. Ultrasonography and pulse wave analysis were used to measure carotid intima-media thickness (IMT) and augmentation index (AIx). RESULTS: OxLDL was correlated with IMT (r = 0.24, P = 0.003), whereas CRP was correlated with AIx (r = 0.21, P = 0.005). No correlation was detected between Hcy and AIx or age-adjusted IMT. There was a significant association between AIx and age 50 years (r = 0.40; P = 0.001). In stepwise regression analysis age, weight, white blood cell count, OxLDL, heart rate and timing of the reflected waveform adjusted for height were significantly and independently associated with IMT (R = 0.41; P < 0.001). At the same time, AIx as the dependent variable correlated positively with age, gender, CRP and mean arterial pressure, and negatively with heart rate, weight and height, in stepwise regression analysis (R = 0.63; P < 0.001). CONCLUSION: The results of the present study showed that CRP, OxLDL, Hcy and age are not similarly related to AIx and IMT in asymptomatic persons. The results suggest that CRP and younger age are related to arterial stiffness, whereas OxLDL and older age become more important determinants of structural changes of the arteries in asymptomatic persons.     

Coffin–Siris Syndrome with obesity,macrocephaly, hepatomegaly and hyperinsulinism caused by a mutation in the ARID1B gene

Coffin–Siris Syndrome (CSS, MIM 135900) is a rare genetic disorder, and mutations in ARID1B were recently shown to cause CSS. In this study, we report a novel ARID1B mutation identified by whole-exome sequencing in a patient with clinical features of CSS. We identified a novel heterozygous frameshift mutation c.1584delG in exon 2 of ARID1B ({"type":"entrez-nucleotide","attrs":{"text":"NM_020732.3","term_id":"297207098","term_text":"NM_020732.3"}}NM_020732.3) predicting a premature stop codon p.(Leu528Phefs*65). Sanger sequencing confirmed the c.1584delG mutation as a de novo in the proband and that it was not present either in her parents, half-sister or half-brother. Clinically, the patient presented with extreme obesity, macrocephaly, hepatomegaly, hyperinsulinism and polycystic ovarian syndrome (PCOS), which have previously not been described in CSS patients. We suggest that obesity, macrocephaly, hepatomegaly and/or PCOS may be added to the list of clinical features of ARID1B mutations, but further clinical reports are required to make a definite conclusion.     

Metabolic factors and oxidative stress in osteoarthritis: a case–control study

Previous studies suggest that metabolic disturbances might be involved in the development of osteoarthritis (OA). Associations have been found between the individual components of metabolic syndrome (MetS) and OA. MetS has been associated with increased oxidative stress (OxS). The study aimed to clarify the role of MetS components in OA and to evaluate the levels of OxS in OA patients and in age-matched controls. Fifty-five patients with end-stage OA (age 63?±?7 years) prior to hip or knee joint replacement surgery and 55 age-, gender- and body mass index matched controls (61?±?8 years) were enrolled in the study. Serum levels of glucose, insulin, c-peptide, cholesterols and OxS markers were recorded. Homeostasis model assessment for insulin resistance was used as the proxy measure of insulin resistance. Radiographic severity was assessed using the Kellgren–Lawrence score. The OA patients had higher total peroxide concentration and oxidative stress index [488 (250–612) μmol/L vs. 326 (168–442) μmol/L, p?=?.011 and 34 (17–51) vs. 20 (11–28), p?=?.002, respectively] and decreased total antioxidant capacity (1.49?±?0.27 vs. 1.66?±?0.27?mmol trolox equivalent/L, p=?.008) compared with the controls. In addition, OA group had significantly higher level of C-peptide compared with the controls [1.8 (0.94–2.47) vs. 1.3 (0.46–1.42) ng/mL, p?<?.001, respectively]. Furthermore, OA radiographic severity was independently associated with LDL-cholesterol (p?=?.007) and oxidized LDL (p?=?.022). This study demonstrates that end-stage OA patients have increased levels of OxS and decreased antioxidant capacity. OA is associated with impaired lipid metabolism and dysglycemia. Our results underline the importance OxS and metabolic disturbances in the pathogenesis of OA.