Biomedical subjects

Q Fan

Publications and source records attributed to Q Fan.

5 recordsLinked to original sources

PubMed1992

Robust adaptive parameter estimators in arrhythmia detection.

The authors consider the statistical analysis of threshold crossing intervals, as applied to estimation of tachycardia rates from intracavitary electrograms. The authors developed a class of robust algorithms designed to produce minimum variance estimates for tachycardia rates. The authors formulated the algorithms using order statistic filters, and obtained the minimum variance unbiased order statistic estimator. The potential gain in efficiency achieved by this approach is demonstrated via a representative example. The results indicated that the order statistics operator can produce dramatic reductions for typical errors in error variance as compared to linear estimators.

Algorithms↗

PubMed1992

[The influence of acupuncture on interleukin 2 interferon-natural killer cell regulatory network of kidney-deficiency mice].

The influence of acupuncture on IL2-IFN-NKC regulatory network was investigated, experiments were performed on kidney-deficiency mice received the treatments of acupuncture of "Zusanli" point. The results showed that the interleukin: (IL:), natural killer cell (NKC) activity and interferon (IFN) from the kidney-deficiency mice were lower than that from the normal mice. Acupuncture increased the levels of all the IL2 and NKC activity, acupuncture promoted Newcastle disease virus (NDV) inducing the IFN of kidney-deficiency mice, but also induced the IFN directly. The results suggests that acupuncture could make positive adjustment to IL2-IFN-NKC regulatory network. It provided new theoretical basis for the principles of acupuncture theory on IL2-IFN-NKC regulatory network put forward in recent years.

Acupuncture Therapy↗

PubMed1992

[Mutagenesis study of ethylmethane sulfonate with shuttle vector plasmid pZ189].

Shuttle vector plasmid pZ189 was used as a molecular tool and the SupF inserted in the plasmid was worked as a target gene for mutagenesis study. The host cells (E. coli MBM 7070) with pZ189 were treated with ethylmethane sulfonate (EMS) and plated on the selective media containing X-gal (5-bromo-4-chloro-3-indolyl-beta-D-galactoside) and IPTG (isopropyl-beta-D-thiogalactoside). The SupF and the LacZ amber mutant carried by the host cells complemented each other and thus made the colonies blue on the selective media. However the colonies derived from the SupF mutants changed the colour from blue to white. The mutant frequencies in a series of experiments with different concentrations of EMS were estimated. Furthermore, the DNA isolated from 5 SupF mutants was digested with restruiction enzyme Hha I. It suggests that the 214 bp Hha I fragments containing mutant SupF could be distinguished from their wild type counterparts by temperature-gradient gel electrophoresis under optimal conditions.

Electrophoresis, Polyacrylamide Gel↗

PubMed1990

Gossypol-induced alterations of aminophospholipid composition in human sperm.

Gossypol-induced alterations of aminophospholipid composition in human sperm were observed and the effects of some factors on these alterations were investigated. The alterations of aminophospholipid composition of human sperm induced by gossypol included a progressive decrease in the levels of phosphatidylethanolamine (PE) and phosphatidylserine (PS) when gossypol concentrations ranged from 5-500 mumol/L, and a progressive increase in the level of (LPE) at lower gossypol concentrations (5-50 mumol/L). The conversion of PE into lysophosphatidylethanolamine (LPE) was strongly enhanced by Ca2+ and inhibited by 0.5 mmol/L EDTA, while PMSF, NEM, iodoacetamide and Zn2+ had no effect. This conversion was weaker in sperm with stripped surface proteins than in normal sperm. In addition, three surface proteins (MW 80, 60 and 40 kD) were fixed on the plasma membrane by gossypol treatment. The significance of gossypol action and the possibility that sperm PLA2, PE and some surface proteins might play an important role in the physiological acrosome reaction of human sperm, as well as in oocyte penetration, are discussed.

Gossypol↗

PubMed1986

Effects of hydrocortisone on carbohydrase concentrations, de novo synthesis and turnover patterns in immature rat intestine.

Hydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase-isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone-treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase-isomaltase pools was generally similar in the hydrocortisone-treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rates of the carbohydrases as a group were found to be similar and did not appear to differ in control and hydrocortisone-treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone-treated group of rats.

Aging↗