Additionally, human placental vein was incubated in Krebs buffer without xanthine or xanthine oxidase to study the effects of St. John's wort on human tissue in vitro.
Jejunal loops were isolated in situ and filled with a Krebs buffer without or with leptin.
Control samples maintained in circulating Krebs' solution without stimulation showed no significant changes in CAP after 4-AP treatment (Fig. 5A).
Fresh non-laboring and laboring pregnant human uterine smooth muscle was dissected in Krebs buffer without Ca+2 so that only myometrium was present.
Briefly, cells were washed with phosphate-buffered saline before incubation in Krebs buffer without glucose for 30 min at 37 °C.
Cells were resuspended in 0.2 ml of 2× Krebs buffer without phosphate plus 0.2 mCi P orthophosphate (Perkin Elmer) and incubated at 26°C for 3 h.
The perfusion of radioisotopes was preceded by a 2-min pre-wash and followed by a 1-min post-wash with the same oxygenated modified Krebs buffer without radioactively labeled tracers.
A total of 2 × 10 metacyclic L. major were collected by centrifugation (800 g) and washed 3× in Krebs buffer without phosphate or FCS (120 mM NaCl, 1 mM KCl, 1.25 mM CaCl2, 1.2 mM MgSO4, 25 mM NaHCO3, 10 mM glucose, 5 mM Hepes pH 7.4).
Briefly, livers of anaesthetized mice were perfused via the portal vein using Krebs–Henseleit buffer (KHB, without Ca2 + and SO42 −) followed by perfusion with KHB containing 0.15 mg/ml collagenase type II (Worthington Biochemical Corporation, Lakewood, NJ), 0.1 mg/ml Pronase E (Merck, Darmstadt, Germany), 2% BSA, and 0.1 mM CaCl2.
We measured NO electrochemically with an NO electrode (ISO-NOP; World Precision Instruments, Stevenage, UK) attached to an amplifier (NO meter; ISO-NO Mark II; World Precision Instruments); the electrode was introduced to the cuvette containing 2 mL Krebs buffer with or without DEP (100 μg/mL), pre-warmed to 37°C and stirred continuously at 1,000 rpm.
