Differentation of the fat body cells in the precocius adults of Schistocerca gregaria: regulation of polyploidy by juvenile hormone

Precocious adults from 2nd and 3rd instar larvae of the desert locust Schistocerca gregaria were used to assess the competence of their fat body to synthesize DNA in response to a juvenile hormone analog (JHA), hydoprene. Autoradiographic studies show that JHA stimulates DNA synthesis since a significant proportion of the fat body nuclei are labelled after treatment with 100 or 200 µg of JHA. Maximum DNA synthesis occurs 24 h after treatment with 100 µg of JHA. The nuclear ploidy classes of the precocious adults from 3rd larvae are similar to those of 1-d-old normal adults, but treatemnt of these precociuos adults with µg of JHA doubles the DNA content resulting in enhanced ploidy classes which resemble those of 10-d-old normal females. In the precocious adults that emerged from 2nd instar larvae the ploidy classes are higher than those of 1-d-old normal adults, and treatment of these precocious adults with JHA results in a further increase in the DNA content of the fat body nuclei leading to the formation of high percentages of 16C and 32C nuclei. The results of these studies suggest that any model on the mode of action of JH should recognize this phenomenon of JH-induced polyploidization in the fat body nuclei

Intradialytic protein ingestion and exercise do not compromise uremic toxin removal throughout hemodialysis

Objective Dietary protein and physical activity interventions are increasingly implemented during hemodialysis to support muscle maintenance in patients with end-stage renal disease (ESRD). Although muscle maintenance is important, adequate removal of uremic toxins throughout hemodialysis is the primary concern for patients. It remains to be established whether intradialytic protein ingestion and/or exercise modulate uremic toxin removal during hemodialysis. Methods We recruited 10 patients with ESRD (age: 65 ± 16 y, BMI: 24.2 ± 4.8 kg/m2) on chronic hemodialysis treatment to participate in this randomized cross-over trial. During hemodialysis, patients were assigned to ingest 40 g protein or a nonprotein placebo both at rest (protein [PRO] and placebo [PLA], respectively) and following 30 min of exercise (PRO + exercise [EX] and PLA + EX, respectively). Blood and spent dialysate samples were collected throughout hemodialysis to assess reduction ratios and removal of urea, creatinine, phosphate, cystatin C, and indoxyl sulfate. Results The reduction ratios of urea and indoxyl sulfate were higher during PLA (76 ± 6% and 46 ± 9%, respectively) and PLA + EX interventions (77 ± 5% and 45 ± 10%, respectively) when compared to PRO (72 ± 4% and 40 ± 8%, respectively) and PRO + EX interventions (73 ± 4% and 43 ± 7%, respectively; protein effect: P = .001 and P = .023, respectively; exercise effect: P = .25 and P = .52, respectively). Nonetheless, protein ingestion resulted in greater urea removal (P = .046) during hemodialysis. Reduction ratios and removal of creatinine, phosphate, and cystatin C during hemodialysis did not differ following intradialytic protein ingestion or exercise (protein effect: P > .05; exercise effect: P>.05). Urea, creatinine, and phosphate removal were greater throughout the period with intradialytic exercise during PLA + EX and PRO + EX interventions when compared to the same period during PLA and PRO interventions (exercise effect: P = .034, P = .039, and P = .022, respectively). Conclusion The removal of uremic toxins is not compromised by protein feeding and/or exercise implementation during hemodialysis in patients with ESRD

Report of the potato mission of the Netherlands industry and knowledge institutions to Myanmar : March 7 - 15, 2015

This report describes a potato mission of the Netherlands industry and knowledge institutions to Myanmar

Estimated GFR, Albuminuria, and Cognitive Performance:The Maastricht Study

BACKGROUND: Reduced estimated glomerular filtration rate (eGFR) and albuminuria have been associated with worse cognitive performance. However, few studies have examined whether these associations are confined to older individuals or may be extended to the middle-aged population. STUDY DESIGN: Cross-sectional analyses of a prospective population-based cohort study. SETTING & PARTICIPANTS: 2,987 individuals aged 40 to 75 years from the general population (The Maastricht Study). PREDICTOR: eGFR and urinary albumin excretion (UAE). OUTCOMES: Memory function, information processing speed, and executive function. MEASUREMENTS: Analyses were adjusted for demographic variables (age, sex, and educational level), lifestyle factors (smoking behavior and alcohol consumption), depression, and cardiovascular disease risk factors (glucose metabolism status, waist circumference, total to high-density lipoprotein cholesterol ratio, triglyceride level, use of lipid-modifying medication, systolic blood pressure, use of antihypertensive medication, and prevalent cardiovascular disease). RESULTS: UAE was <15mg/24 h in 2,439 (81.7%) participants, 15 to <30 mg/24 h in 309 (10.3%), and ≥30mg/24 h in 239 (8.0%). In the entire study population, UAE≥30mg/24 h was associated with lower information processing speed as compared to UAE<15mg/24 h (β [SD difference] = -0.148; 95% CI, -0.263 to -0.033) after full adjustment, whereas continuous albuminuria was not. However, significant interaction terms (P for interaction < 0.05) suggested that albuminuria was most strongly and extensively associated with cognitive performance in older individuals. Mean (±SD) eGFR, estimated by the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine-cystatin C equation (eGFRcr-cys), was 88.4±14.6 mL/min/1.73m(2). eGFRcr-cys was not associated with any of the domains of cognitive performance after full adjustment. However, significant interaction terms (P for interaction < 0.05) suggested that eGFRcr-cys was associated with cognitive performance in older individuals. LIMITATIONS: Cross-sectional design, which limited causal inferences. CONCLUSIONS: In the entire study population, albuminuria was independently associated with lower information processing speed, whereas eGFRcr-cys was not associated with cognitive performance. However, both were more strongly and extensively associated with cognitive performance in older individuals

Zeolite-like liquid crystals

Zeolites represent inorganic solid-state materials with porous structures of fascinating complexity. Recently, significant progress was made by reticular synthesis of related organic solid-state materials, such as metal-organic or covalent organic frameworks. Herein we go a step further and report the first example of a fluid honeycomb mimicking a zeolitic framework. In this unique self-assembled liquid crystalline structure, transverse-lying π-conjugated rod-like molecules form pentagonal channels, encircling larger octagonal channels, a structural motif also found in some zeolites. Additional bundles of coaxial molecules penetrate the centres of the larger channels, unreachable by chains attached to the honeycomb framework. This creates a unique fluid hybrid structure combining positive and negative anisotropies, providing the potential for tuning the directionality of anisotropic optical, electrical and magnetic properties. This work also demonstrates a new approach to complex soft-matter self-assembly, by using frustration between space filling and the entropic penalty of chain extension

Association between routine and standardized blood pressure measurements and left ventricular hypertrophy among patients on hemodialysis

<p>Abstract</p> <p>Background</p> <p>Left ventricular (LV) hypertrophy is common among patients on hemodialysis. While a relationship between blood pressure (BP) and LV hypertrophy has been established, it is unclear which BP measurement method is the strongest correlate of LV hypertrophy. We sought to determine agreement between various blood pressure measurement methods, as well as identify which method was the strongest correlate of LV hypertrophy among patients on hemodialysis.</p> <p>Methods</p> <p>This was a post-hoc analysis of data from a randomized controlled trial. We evaluated the agreement between seven BP measurement methods: standardized measurement at baseline; single pre- and post-dialysis, as well as mean intra-dialytic measurement at baseline; and cumulative pre-, intra- and post-dialysis readings (an average of 12 monthly readings based on a single day per month). Agreement was assessed using Lin's concordance correlation coefficient (CCC) and the Bland Altman method. Association between BP measurement method and LV hypertrophy on baseline cardiac MRI was determined using receiver operating characteristic curves and area under the curve (AUC).</p> <p>Results</p> <p>Agreement between BP measurement methods in the 39 patients on hemodialysis varied considerably, from a CCC of 0.35 to 0.94, with overlapping 95% confidence intervals. Pre-dialysis measurements were the weakest predictors of LV hypertrophy while standardized, post- and inter-dialytic measurements had similar and strong (AUC 0.79 to 0.80) predictive power for LV hypertrophy.</p> <p>Conclusions</p> <p>A single standardized BP has strong predictive power for LV hypertrophy and performs just as well as more resource intensive cumulative measurements, whereas pre-dialysis blood pressure measurements have the weakest predictive power for LV hypertrophy. Current guidelines, which recommend using pre-dialysis measurements, should be revisited to confirm these results.</p

The role of epigenetics in renal ageing

An ability to separate natural ageing processes from processes specific to morbidities is required to understand the heterogeneity of age-related organ dysfunction. Mechanistic insight into how epigenetic factors regulate ageing throughout the life course, linked to a decline in renal function with ageing, is already proving to be of value in the analyses of clinical and epidemiological cohorts. Noncoding RNAs provide epigenetic regulatory circuits within the kidney, which reciprocally interact with DNA methylation processes, histone modification and chromatin. These interactions have been demonstrated to reflect the biological age and function of renal allografts. Epigenetic factors control gene expression and activity in response to environmental perturbations. They also have roles in highly conserved signalling pathways that modulate ageing, including the mTOR and insulin/insulin-like growth factor signalling pathways, and regulation of sirtuin activity. Nutrition, the gut microbiota, inflammation and environmental factors, including psychosocial and lifestyle stresses, provide potential mechanistic links between the epigenetic landscape of ageing and renal dysfunction. Approaches to modify the renal epigenome via nutritional intervention, targeting the methylome or targeting chromatin seem eminently feasible, although caution is merited owing to the potential for intergenerational and transgenerational effects