Beckman creatinine analyzer 2

Covariates were chosen a priori and included age, smoking status, body mass index (BMI), and dietary vitamin C and calcium intake based on previous studies of factors predicting lead concentrations [30 (link),31 (link)]. Age and smoking status were obtained via self-administered questionnaires at each NAS regular visit. Cigarette smoking was categorized as current vs. former vs. never smoking. BMI was calculated as weight (kg)/height (m²) obtained during physical examination. To assess the dietary intake, we used a validated, semi-quantitative food frequency questionnaire adapted from the one used in the Nurses’ Health Study that inquired about the average consumption of 135 food items during the past year [32 (link),33 (link),34 (link)]. Dietary calcium, vitamin C, and total energy intake were computed from the reported frequency of consumption of each specified unit of food and from published data on the nutrient content of the specified portions [34 (link)]. Creatinine in serum and 24-h urine samples were determined by a Jaffe rate reaction with a Beckman Creatinine Analyzer 2 (Beckman, Brea, CA, USA). Urinary N-telopeptide (NTx) was analyzed with a commercially available competitive-inhibition enzyme-linked immunosorbent assay (Osteomark; Ostex International, Seattle, WA, USA) and was expressed as creatinine corrected bone collagen equivalents (nM BCE/mM creatinine).

Blood samples were collected from the injured and sham rats daily across a week in 1 mL Eppendorf heparin-treated tubes after making small incisions on their tails. These samples were centrifuged at 100,000–130,000 rpm for 10 min. The supernatants were then stored at 4 °C. A quantitative determination of creatine kinase activity in serum was then estimated with Pointe Scientific CK (Liquid) Reagents (Point Scientific, Inc., Canton, MI, USA). Measurements were performed with a Beckman Creatinine Analyzer 2 (Beckman Instruments, Brea, CA, USA) according to the manufacturer’s specifications and reported values in milligrams per deciliter (mg/dL). Approximately 10 μL of each serum sample was added to the working reagent (1000 μL), and the absorbance was immediately measured using a microplate reader. Likewise, blood urea nitrogen levels were investigated with the Liquid Urea Nitrogen (BUN) Reagent Set (Pointe Scientific, Canton, MI, USA) according to the manufacturer’s specifications. Briefly, a 1000 μL working reagent was prepared by 1 part of the coenzyme combined with 5 parts of the enzyme reagent, to which 10 μL of each serum sample was added, and absorbance was immediately measured using a microplate reader.

Blood samples were collected from the rats in 1 mL Eppendorf heparin-treated tubes after making small incisions on their tails. These samples were centrifuged at 100,000–130,000 rpm for 10 min. The supernatants were then stored at 4°C. Quantitative determination of creatine kinase activity in serum was then estimated with Pointe Scientific CK (Liquid) Reagents (Point Scientific, Inc., Canton, MI, USA). Serum creatinine (SCr) measurements were performed with a Beckman Creatinine Analyzer 2 (Beckman Instruments, Brea, CA, USA) according to the manufacturer’s specifications and reported in milligrams per deciliter (mg/dL). Sera blood urea nitrogen (BUN) measurements were made using the Liquid Urea Nitrogen Reagent Set (Pointe Scientific, Canton, MI, United States), whereby the working reagent was prepared by mixing five parts of the enzyme reagent (R1) with 1 part of coenzyme (R2) reagent. Approximately 10 μL of each serum sample was added to the working reagent (1,000 μL), and the absorbance was immediately measured using a microplate reader. The levels of these metabolites were measured before all forms of IRI were induced and monitored across the subsequent 14 days to investigate the effect of IDH2 hydrodynamic-based injections.