Biomedical subjects

Fang Xu

Publications and source records attributed to Fang Xu.

62 records · Page 4Linked to original sources

PubMed2003

[The effect of treating obstructive disease of lacrimal passage by lacrimal plastic operation with Nd:YAG laser].

OBJECTIVE: To study the therapeutic effects of Nd:YAG laser on obstructive diseases of the lacrimal passage. METHODS: 693 eyes in 603 cases with obstructive diseases of lacrimal passage, including obstruction of lacrimal puncta (23 eyes), lacrimal duct (192 eyes), nasolacrimal duct (227 eyes), chronic dacryocystitis (231 eyes), and traumatic laceration of lacrimal canaliculus (20 eyes), were treated by lacrimal plastic operation with Nd:YAG laser and the therapeutic effects were compared among the groups. RESULTS: The cure rates and effective rates of the five diseases were 86.9% and 95.7%, 89.1% and 93.8%, 93.0% and 96.0%, 78.4% and 82.7%, 40.0% and 65.0%, respectively. By Ridit analysis, R +/- S(R) values for each group were 0.921 +/- 0.023, 0.914 +/- 0.009, 0.927 +/- 0.007, 0.856 +/- 0.013, 0.749 +/- 0.055. CONCLUSIONS: The therapeutic effect on chronic dacryocystitis is less than those of obstruction of nasolacrimal duct and lacrimal duct (P < 0.05). The therapeutic effect on traumatic laceration of lacrimal canaliculus is less than that of the other four groups (P < 0.05). Therefore, it should be restricted on indication for the cases of chronic dacryocystitis and traumatic laceration of lacrimal canaliculus.

Adolescent↗

PubMed2002

Study on the effect of electromagnetic impulse on neurotransmitter metabolism in nerve cells by high-performance liquid chromatography-electrochemical detection coupled with microdialysis.

In this paper, a reverse-phase high-performance liquid chromatographic method using a chemically modified electrode coupled with microdialysis was developed to study the effect of electromagnetic impulse (EMI) on monoamine neurotransmitter metabolism in nerve cells. To detect the monoamines and their metabolites, a poly (para-aminobenzoic acid) (P-pABA)-modified electrode was prepared. The modified electrode exhibited efficiently electrocatalytic oxidation for monoamines and their metabolites with relatively high sensitivity, stability, and long life. Nerve cells were primarily cultured. EMI was radiated to three experimental model nerve cells: (i) on mature nerve cells, (ii) on the culture medium, and (iii) on juvenile nerve cells for various periods of time. Then the levels of monoamines in the culture medium were detected by high-performance liquid chromatography-electrochemical detection. The data indicated that electromagnetic fields could influence neurotransmitter metabolism by direct effect on nerve cells or effect on the nutrient medium and that the effect was not only relevant with the length of radiation time, but also with the growing state of the nerve cells.

4-Aminobenzoic Acid↗

PubMed2002

Amperometric determination of glutathione and cysteine on a Pd-IrO(2) modified electrode with high performance liquid chromatography in rat brain microdialysate.

A Pd/IrO(2) co-electrodeposited glassy carbon electrode was prepared and the electrochemical behavior of glutathione (GSH) at this chemically modified electrode (CME) has been studied by cyclic voltammetry (CV). The results indicated that the modified electrode efficiently exhibited electrocatalytic oxidation for GSH with relatively high sensitivity, stability, and long-life. Coupled with high-performance liquid chromatography (HPLC), the Pd/IrO(2) modified electrode was utilized for the electrochemical detection (ECD) of the thiocompounds, glutathione and cysteine (Cys). The peak currents were linear with the substance concentrations in the range of 1.0 x 10(-5) mol L(-1) to 8.0 x 10(-4) mol L(-1) for GSH and 4.0 x 10(-6) mol L(-1) to 2.0 x 10(-4) mol L(-1) for Cys. The detection limits were 2.0 x 10(-6) mol L(-1) for GSH and 5.0 x 10(-7) mol L(-1) for Cys with S/N of 3. The method has been successfully applied to assess the contents of GSH and Cys in rat brain microdialysates.

Animals↗

PubMed2002

Liquid chromatography/tandem mass spectrometry for the determination of fluoxetine and its main active metabolite norfluoxetine in human plasma with deuterated fluoxetine as internal standard.

Fluoxetine (F) and its N-demehylated metabolite norfluoxetine (NF) are selective inhibitors of serotonin reuptake in humans. A new sensitive rapid method for the simultaneous determination of F and NF in plasma was established and validated, and was further applied to assess the bioequivalence of two oral formulations of F in 22 healthy Chinese male volunteers who received a single oral dose of each formulation (containing 20 mg of fluoxetine hydrochloride). The new method involves using liquid chromatography/tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode with deuterated fluoxetine (DF) as internal standard. High levels of analytical sensitivity and specificity of MS/MS detection enabled use of a simple liquid-liquid extraction procedure. The combination of a simple sample clean-up procedure and short chromatographic run-time (5 min) considerably increased the productivity of the analytical method. The method was validated for the plasma concentration range 0.27-22 ng/mL for both of the test compounds, and the calibration curves were linear with coefficients of correlation >0.999. The limit of detection was 0.1 ng/mL for plasma F and NF. Taking the plasma sample size (200 micro L) into account the new method for determination of F and NF is more sensitive than those described previously.

Adult↗

PubMed2002

Efficacy of gene therapy for a prototypical lysosomal storage disease (GSD-II) is critically dependent on vector dose, transgene promoter, and the tissues targeted for vector transduction.

Lysosomal storage diseases are an intriguing target for gene therapy approaches, as transduction of a "depot" organ with a transgene encoding a lysosomal enzyme can be followed by secretion, systemic distribution, downstream uptake, and lysosomal targeting of the enzyme into non-transduced tissues. These benefits are of utmost importance when considering gene therapy approaches for glycogen storage disease type-II (GSD-II). GSD-II is a prototypical lysosomal storage disorder caused by lack of intralysosomal acid alpha-glucosidase (GAA) activity. Lack of GAA can result in a proximal limb myopathy and respiratory and cardiac failure, each due to abnormal glycogen accumulation in the skeletal muscles or cardiac tissues, respectively. After converting the liver into a "depot" organ, we found that intravenous injection of the [E1-,polymerase-]AdGAA vector allowed for hepatic secretion of GAA over an at least 20-fold dosage range. We noted that very low plasma GAA levels (derived from hepatic secretion of GAA) can allow for GAA uptake by muscle tissues (skeletal or cardiac), but significantly higher plasma GAA levels are required before glycogen "cross-correction" can occur in these same tissues. We also demonstrated that liver-specific enhancer/promoters prolonged GAA transgene expression from persistent [E1-,polymerase-] adenovirus based vector genomes for at least 180 days, and significantly diminished the amounts of neutralizing anti-GAA antibodies elicited in this animal model. Finally, we demonstrated that skeletal muscles can also serve as a "depot" organ for GAA secretion, allowing for secretion of GAA and its uptake by noninfected distal tissues, although glycogen reductions in non-injected muscles were not achieved by the latter approach.

Adenoviridae↗

PubMed2002

A new haplogroup pattern displayed in Fujian Han in China.

Human Y-chromosomal binary polymorphisms have been considered to preserve the paternal genetic legacy and provide evidence on human evolution and the genetic relationships among and demographic history of different populations. To reveal the genetic origin and immigration of the Fujian Han, 13 binary markers on the Y chromosome were used to screen Fujian Han by allele-specific polymerase chain reaction. The results indicated that the M9G marker was highly prevalent (96.20%), suggesting a significant genetic drift. In addition, M122C frequency was only 22.78%, and M45A and M103T were default. The distinctive haplogroup frequencies (H1, H5, and H6/7/8) imply that the haplogroup pattern is a relatively ancestral and interim type.

Asian People↗

PubMed2002

Distribution of the CCR5 gene 32-basepair deletion in 11 Chinese populations.

A mutant allele of the chemokine receptor gene CCR5 bearing a 32-basepair deletion (delta 32CCR5) could increase the resistance to HIV-1 infection or delayed progression to AIDS. The frequency of this mutation is higher in Europeans than in Asians. To investigate the distribution of this polymorphism in China, 715 individuals from 11 Chinese populations were screened by PCR, including the Han and 10 other ethnic groups. The delta 32CCR5 gene was found in 16 individuals from 5 ethnic groups. All of them were heterozygous. The frequency of the mutant alleles of delta 32CCR5 is low in China and reflects (or might reflect) ancestral gene flow from Europe to Chinese ethnic groups and recent intermarriage within the ethnic groups.

Acquired Immunodeficiency Syndrome↗

PubMed2002

[The update achievements on the relation between free radical and leukemia].

Free radicals are a group of charged atoms, molecules or ions with strong biological activity, which play an important role in pathogenesis of cancers and many other diseases. Free radicals are produced and consumed by a serial of chain reactions. Free radicals can activate pro-oncogenes, impact the signal transduction about the apoptosis, survival and proliferation of tumor cells modify the key enzymes or proteins functions, and might cause carcinogenesis. Meanwhile, free radicals damage the tissues and organs and bring about a variety of pathological changes. On the other hand, free radicals are involved in the effects of some anti-leukemic drugs as intermediates or functional substances.

Animals↗