Regulation of brain m calpain Ca2+ sensitivity by mixtures of membrane lipids: Activation at intracellular Ca2+ level

Combinations of certain phospholipids and gangliosides increase the specific activity of m calpain and can activate m calpain at 1 to 10 μM Ca²⁺ concentration. However, this level of calcium is still greater than the normal intracellular calcium level. We have used combinations of lipids to demonstrate the m calpain activity at the physiological Ca²⁺ level. GD1a (100 μM) and cerebroside (Cerb; 750 μM; 1:7.5) mixture was the most effective. At 0.5 μM to 1.0 Ca²⁺ concentrations, 15–20% of the maximal activity was detected for the purified myelin and cytosolic m calpains. Other combinations were GD1a (100 μM), GM1 (100 μM), Cerb (750 μM), sulfatide (Sulf; 750 μM), and phosphatidylinositol (PI; 300 μM) at a ratio of 1:1:7.5:7.5:3, respectively. These lipid mixtures stimulated calpain activity at three- to tenfold less calcium concentration than control. The other mixtures, including GD1a:Sulf (1:9) > GD1a:PI (1:4) > PI:Sulf (1:5) > Cerb:Sulf (1:5) and PI:Cerb (1:2.5), also stimulated calpain activity at 1.0 μM Ca²⁺ concentration. Triton X-100, oxidized glutathione (GSSG), and calpain activator did not affect the Ca²⁺ requirement. Liposomes containing GD1a, Cerb, and m calpain also showed recognizable calpain activity at a significantly reduced Ca²⁺ concentration (0.4 μM), confirming the glycolipid-mediated enzyme modulation. These studies indicate that specific lipid mixtures can stimulate m calpain activity at an intracellular level of Ca²⁺. © 1996 Wiley-Liss, Inc.     

Practical aspects of electrophoretic deposition to produce commercially viable supercapacitor energy storage electrodes

Electrophoretic deposition (EPD) is a highly convenient and demonstrated industrial operation for the manufacture of surface coatings. Recent years are seeing increasing evidence in using this technique to produce energy storage electrodes (notably for lithium-ion batteries, solid-state devices, supercapacitors, and flow batteries), but their advancement for industrialisation remains unclear. Using activated carbon (AC) as an exemplary supercapacitor material, this study reports the practical aspects of porous energy storage electrodes produced by the EPD technique. Practical electrodes with commercially viable parameters are shown, specifically high density active material (in excess of 9.8 mg cm⁻²) and very thick coating layer (about 168 μm). Research investigations including colloidal electrolyte formulations, electrode deposition parameters and cell performance testing are reported. Materials and electrode properties were studied by various charactersisation tools. Prototype A7 sized pouch cells were assembled and tested to show evidence of practical EPD electrodes in a commercial cell format. Electrochemical performance of EPD over slurry casting is presented. In short, this research shows the successful production of practical EPD electrodes for electrochemical energy storage, which is directly relevant for scale-up industrial adoption and can be applied as a platform electrode manufacturing technology for any battery and supercapacitor materials.

Electrophoretic deposition (EPD) is a highly convenient and demonstrated industrial operation for coatings manufacture. It is now suitable for the production of practical energy storage electrodes for batteries, capacitors & solid-state devices.     

Prolonged intraperitoneal dwell decreases ultrafiltration coefficient in rabbits

In rabbits undergoing peritoneal dialysis, hypertonic (6% dextrose) dialysis solution increased the net ultrafiltration rate (UF) from 233 to 462 microL/kg/min, which was not proportional to the increment in the osmotic gradient, so the ultrafiltration coefficient decreased. As intraperitoneal dwell of hypertonic dialysate was prolonged, the gross and net UFs and ultrafiltration coefficients decreased, and the UF per dextrose absorption declined. The decrement in UF was multifactorial, including a component of fluid and solute stagnation, increasing the distance over which osmotic forces must exert their effects. Excessively hypertonic dialysis fluid should be used only briefly to achieve ultrafiltration efficiently and to avoid the high dextrose loading.     

Adiponectin levels are high in children with classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency

Objective: It has been shown that adiponectin serves as an insulin-sensitizing adipokine. Serum concentrations of adiponectin are low in children with obesity, and increase with fat mass loss, indicating that adiponectin can serve as a biomarker. Since the prevalence of overweight and obesity is increased in children with congenital adrenal hyperplasia (CAH), our study aimed to evaluate serum levels of adiponectin in a cohort of CAH children and adolescents, and their associations with clinical parameters such as chronological age (CA), body mass index (BMI), Tanner stage (TS), medication and metabolic control.
Patients and methods: We studied 51 patients, aged between 5.6 and 19.6 years (median 11.8; 30 females, 21 males), cross-sectionally. All patients had genetically confirmed CAH and received standard steroid substitution therapy. Adiponectin was measured by an enzyme linked immunoassay. Since BMI SDS of the CAH cohort were significantly higher compared to the reference population, we built matched pairs with healthy Caucasian subjects from a normal representative cohort for sex, Tanner stage, chronologic age and BMI.
Results: Adiponectin concentrations were significantly higher in CAH patients (median 11 μg/L) compared to the matched controls (6.7 μg/L, p < 0.0001). Correlation analyses in CAH patients revealed a significant inverse relationship between adiponectin and CA, TS, BMI, serum DHEAS and serum testosterone, but no correlation with hydrocortisone and fludrocortisone dosage.
Conclusion: Currently, the importance of the elevated adiponectin concentrations in CAH children for risk assessment is not clear. However, our data imply that besides adequate metabolic control of glucocorticoid substitution, a long-term follow-up of other metabolic markers of insulin resistance should be conducted in CAH patients.