Effects of unsaturated fatty acids on calcium-activated potassium current in gastric myocytes of guinea pigs.

Aim: To investigate the effects of exogenous unsaturated fatty acids on calcium-activated potassium current (I(K(Ca))) in gastric antral circular myocytes of guinea pigs.

Methods: Gastric myocytes were isolated by collagenase from the antral circular layer of guinea pig stomach. The whole-cell patch clamp technique was used to record I(K(Ca)) in the isolated single smooth muscle cells with or without different concentrations of arachidonic acid (AA), linoleic acid (LA), and oleic acid (OA).

[Construction of HLA-A2-peptide tetramer and application in HBV/HCV infection].

Objective: To construct HBV and HCV-specific HLA-A2-peptide tetramers, and to direct clinical therapy.

Methods: Recombinant class I HLA-A2 heavy chains and beta-2 M were produced in Escherichia coli cells transformed with pBV220 vectors. Only the extracellular domain of class I heavy chain was expressed, following modification by replacement of the C-terminal domain with a substrate sequence for BirA biotinylation.

Effect of actin microfilament on potassium current in guinea pig gastric myocytes.

Aim: To investigate the effect of actin microfilament on potassium current and hyposmotic membrane stretch-induced increase of potassium current in gastric antral circular myocytes of guinea pig.

Methods: Whole-cell patch clamp technique was used to record potassium current in isolated gastric myocyes.

Results: When the membrane potential was clamped at -60 mV, an actin microfilament disruptor, cytochanlasin-B(Cyt-B, 20 micromol/L in pipette) increased calcium-activated potassium current (I(K(Ca))) and delayed rectifier potassium current (I(K(V))) to 138.

Cloning, expression, and purification of HLA-A2-BSP and beta-2m in Escherichia coli.

Tetramer analysis is a novel technique in immunological research that has dramatically changed our knowledge of the immune response to pathogens, tumors and autoimmune disease. Through the formation of major histocompatibility complex (MHC)-peptide tetrameric complexes, it can provide accurate counts of antigen-specific T-cells and it allows their phenotypical and functional analysis. The tetramer is composed of the human leukocyte antigen (HLA) heavy chain, beta-2 microglobulin (beta-2m), the nominal peptide, and streptavidin.

Inhibitory effect of C-type natriuretic peptide on spontaneous contraction in gastric antral circular smooth muscle of rat.

Aim: To investigate the effect of natriuretic peptides on gastric motility and its possible mechanism.

Methods: Spontaneous contraction of gastric antral circular muscle of rats was recorded by four channel physiograph. The concentration of cyclic guanosine monophosphate (cGMP) was measured by radioimmunoassay.

Role of calcium mobilization in sodium nitroprusside-induced increase of calcium-activated potassium currents in gastric antral circular myocytes of guinea pig.

Aim: To investigate the role of calcium mobilization in the calcium-activated potassium currents [IK(Ca)] increased by sodium nitroprusside (SNP), a nitric oxide (NO) donor, in gastric antral circular myocytes of the guinea pig.

Methods: A perforated patch-clamp technique was used, and the myocytes were isolated by collagenase.

Results: SNP 100 mol/L significantly increased IK(Ca), and enhanced the spontaneous transient outward currents (STOC).

Role of actin microfilament in hyposmotic membrane stretch-induced increase in muscarinic current of guinea-pig gastric myocytes.

To investigate the relationship between cytoskeleton and hyposmotic membrane stretch-induced increase in muscarinic current, the role of actin microfilament in hyposmotic membrane stretch-induced increase in muscarinic current was studied with the whole-cell patch clamp technique in guinea-pig gastric myocytes. In this study, the muscarinic current was induced by carbachol (50 micromol/L) or GTPgammaS (0.5 mmol/L).

Role of unsaturated fatty acids in the enhancement of muscarinic current by hyposmotic membrane stretch in guinea pig smooth muscle cells.

To investigate the function of exogenous unsaturated fatty acids in hyposmotic membrane stretch enhancement of muscarinic current (ICCh) in antral circular smooth muscle cells of guinea pig, we recorded the membrane current with the conventional whole cell patch-clamp technique. I(CCh) elicited by 50 micromol/L carbachol (CCh) at the holding potential of 20 mV under isosmotic condition was taken as control. Hyposmotic membrane stretch increased I(CCh) to 226.

Intracellular calcium was involved in muscarinic currents increased by hypoosmotic membrane stretch in gastric myocytes of guinea pig.

Aim: To investigate the role of intracellular calcium in muscarinic currents increased by hypoosmotic membrane stretch in gastric antral circular myocytes of the guinea pig.

Methods: The whole cell patch-clamp technique was used, and the myocytes were isolated by collagenase. Cells were swelled by hypoosmotic solution (200 Osmmol/kg).