Biomedical subjects

X Y Hu

Publications and source records attributed to X Y Hu.

At least 19 recordsLinked to original sources

PubMed2006

Reduced semen quality in chronic prostatitis patients that induce the release of apoptotic protein Omi/HtrA2 from spermatozoa.

The relationship between chronic prostatitis and fertility has been disputed for many years. Several groups have shown infection and autoimmune response against prostate antigens could have a deleterious effect on semen quality and fertility. This study was conducted to test the hypothesis that Omi/HtrA2-induced apoptosis in chronic prostatitis could be a mechanism underlying the observed clinical benefit. The Omi/HtrA2 serine protease is a nuclear-encoded mitochondrial protein, which can be released from mitochondria into the cytosol after apoptosis stimuli, inducing apoptosis in caspase-dependent and independent manners. Forty-one patients diagnosed as suffering from chronic prostatitis were included. Healthy normal individuals were included as controls. Human spermatozoa in the semen were purified by Percoll-gradient technique to separate the seminal plasma and other round cells. Measurements for sperm concentration, motility, morphology, proinflammatory cytokines, Omi/HtrA2 mRNA and protein levels in spermatozoa of chronic protatitis patients, were performed accordingly. Significantly increased levels of proinflammatory cytokines were detected in seminal plasma from these prostatitis patients. Omi/HtrA2 mRNA and protein levels were significantly higher in prostatitis men than in normal men. This study shows that chronic prostatitis patients present important alterations in their semen quality parameters, Omi/HtrA2 mRNA and protein levels of spermatozoa. We speculate that the inflammatory process involved may affect male fertility by release of proapoptotic protein Omi/HtrA2.

Adolescent↗

PubMed2001

[The development of dental silver amalgam glass ionomer cement].

To eliminate the harm of mercury, we, by means of special technology, have developed a new type of dental filling material, comprising of glass ionomer and 100% ultra-fine ball-shaped silver amalgam powder. Clinical applications show it has very good wear-resistant, pressure-resistant and adhesive properties Moreover, it causes no irritation to the dental pulp and is a good kind of dental filling material in clinical applications.

Adolescent↗

PubMed2001

[A statistical wavelength selection method of infrared spectra used in exhaust gas detection].

In order to extract the quantitative features of the rare pollution components from noisy atmospheric infrared spectra and thus create calibration models, a wavelength selection method based on statistic theory is proposed in this paper. In this method, an objective function is defined based on the estimation of spectral noise level at every wavelength position. Because the size of the wavelength subset is also included in the function, the model size will not become too big during the minimization of the error of the calibration model. To test the performance of this method, the wavelength subsets of measured spectra with background noises were selected and the calibration models were then created using neural network technique for three pollution gases, respectively. The test showed that the sizes of the selected wavelength subsets accorded with the calculated results. The subset sizes were less than 2% of the total wavelength points. Meantime, the spectral noises were also restrained markedly in the calibration model because of the wavelength selection. The experimental results proved the validity of the wavelength selection method.

Air Pollutants↗

PubMed2001

[Maximal entropy principle wavelet denoising].

In the filed of wavelet denoising, an essential problem is how to determine the cutting threshold of wavelet coefficients that divides the coefficients corresponding to signal and noise respectively. The wavelet denoising method discussed here determines this threshold by using the maximal entropy principle (MEP) of information theory. From the basic principle of probability theory, it can be deduced that the detailed wavelet coefficients sequence of an arbitrary distributed random noise sequence satisfies a normal distribution. Based on this conclusion, an optimal threshold is determined using MEP. Such that the coefficients whose absolute values are less than the threshold satisfies a normal probabilistic distribution. This threshold is an optimal value that distinguishes the wavelet coefficients of signal and noise in view of statistics. The simulation analysis using spectral data and the comparison with other methods showed that this method provides a best improvement of signal-to-noise ratio, and its performance is least sensitive to the change of signal-to-noise ratio.

Algorithms↗

PubMed2001

[Input layer self-construction neural network and its use in multivariant calibration of infrared spectra].

In order to solve the problems of feature extraction and calibration modelling in the area of quantitatively infrared spectra analysis, an input layer self-constructive neural network (ILSC-NN) is proposed. Before the NN training process, the training data is firstly analyzed and some prior knowledge about the problem is obtained. During the training process, the number of the input neurons is determined adaptively based on the prior knowledge. Meantime, the network parameters are also determined. This algorithm of the NN model helps to increase the efficiency of calibration modelling. The test experiment of quantitative analysis using simulated spectral data showed that this modelling method could not only achieve efficient wavelength selection, but also remarkably reduce the random and non-linear noises.

Algorithms↗

PubMed1995

Identification of dihydroetorphine in biological fluids by gas chromatography-mass spectrometry.

A method for the monitoring of dihydroetorphine hydrochloride, a powerful anaesthetic and analgesic drug, in biological fluids was developed, involving GC-MS with multiple selected-ion monitoring. Dihydroetorphine was extracted from human blood and urine with dichloromethane and then derivatized with N-heptafluorobutyrylimidazole after having been concentrated to dryness. A dihydroetorphine monoheptafluorobutyl derivative was formed, which showed good behaviour in GC-MS with electron impact ionization. Its molecular ion, m/z 609, and its main fragments, m/z 576, 534, 522 and 508, were selected as the ions for identification owing to their relative peak intensities and characteristics. The target drug was identified based on its retention time, its selected multiple ions and their relative intensities. This method was successfully used for the detection of dihydroetorphine in blood and urine from a dihydroetorphine addict and a poisoned patient, respectively.

Etorphine↗

PubMed1995

[Studies on the synthesis and structure-activity relation of deltorphin I analogues].

Endogenous opioid deltorphin I (DEL I) and its three analogues (progressive, stepwise repositioning of Asp from 5 to 7) were synthesized by solid phase method. DEL I at 10(-14)-10(-10) mol.L-1 in vitro and at 0.5-5 micrograms.kg-1 in vivo was found to increase the percentages of erythrocyte rosette forming cells (E-RFC) and red blood cell C3b receptor garland (RBC-CR1). This augmentative effect of DEL I was antagonized by naloxone. The results indicate that DEL I enhanced the immune function of rats. The order (from strong to weak) of the analgesic and immune activity was shown to be Asp4, Asp7, Asp5, Asp6 and Asp4, Asp7, Asp6, Asp5 respectively.

Analgesics, Opioid↗

PubMed1994

[Quantitative analysis of bencynonate in human plasma using a deuterated internal standard by GC-MS/SIM].

Bencynonate is a newly developed anticholinergic drug. After a dose (2 mg/person or 4 mg/person) of bencynonate, the circulating concentrations are so low that therapeutic drug monitoring studies have previously been impossible. Radioisotope assay and radioaccepter assay had been used in rat experiments, but the detections limits of these methods were not sensitive enough for the therapeutic drug monitoring. Further, the two methods were unsuitable in the human. For evaluation of the pharmacokinetics and the relative bioavailability of bencynonate in man, a gas chromatographic--mass spectrometric method for quantitative analysis of bencynonate in human plasma was developed. Deuterated bencynonate served as the internal standard and selected-ion monitoring of the fragments of bencynonate and internal standard permitted the quantitation of bencynonate down to 25 pg.ml-1 of plasma. The linearity was in the range from 25 pg.ml-1 to 3 ng.ml-1 of bencynonate plasma concentration. At 0.25 ng.ml-1 level the recovery and relative standard deviation of variation are 54.3% and 19.1%, respectively. Application of the method to clinical studies gave the results of pharmacokinetics and relative bioavailability of bencynonate in man.

Animals↗

PubMed1994

[Monitoring of dihydroetorphine hydrochloride in biological fluid].

A method for the monitoring of dihydroetorphine hydrochloride, a powerful anesthetic and analgesic drug, in biological fluid was developed by means of GC-MS with selected ion monitoring. Dihydroetorphine was extracted from human blood and urine with dichloromethane, and then was derivatized with N-heptafluorobutyrylimidazole after it was concentrated to dryness. A dihydroetorphine monoheptafluorobutyl derivative was formed, which showed good characteristics on GC-MS with electronic impact mode. Its M+ was m/z 609. Besides this, its main fragments included m/z 576, 534, 522 and 508. These main ions were all selected as the ions of identification due to their relative peak intensity and stability. The detection limit was 1 pg. The target drug was identified based on its retention time multiple ion monitoring and relative peak intensity. This method has been successfully used for detection of dihydroetorphine hydrochloride in blood and urine from dihydroetorphine addict and poisoned patient, respectively. Good results have been obtained.

Etorphine↗

PubMed1994

[Synthesis and biological activity of an analogue of active fragment (SP-6) of substance P].

SP-6 was synthesized by solid phase method in 95% purity on HPLC. The data obtained from amino acid analysis and fast atom bombardment were in good agreement with theoretical values. Intravenous injection of SP-6 in rabbits at the dosage of 14.3 micrograms/kg. resulted in blood pressure reduction of 4.4 kPa, i.e. 34% (P < 0.001). When the concentration of SP-6 in Tyrode solution was 5.2 x 10(-4) mg/ml the contraction of rabbit duodenum longitudinal muscle increased by 105%. (P < 0.001). When the concentration was more than 1 x 10(-3) mg/ml, the contractile effect was restrained significantly. Dropping 30 microliters of SP-6 (1 x 10(-3) mg/ml) to toad intestinum tenue mesenteriale in situ, the mesentery arterioles were expanded by 30%.

Animals↗

PubMed1994

[Analysis of meperidine and its metabolites in urine of an addict by GC/FID and GC/MS].

Analytical methods of GC/FID and GC/MS for identification and determination of meperidine, an analgesic drug, and its metabolites were established. The determination of meperidine spiked in urine was shown to have a good linear relationship in the range of 0.1-8.0 micrograms/ml urine (Y = 0.4995X + 0.1201, r = 0.9996). The detection limit was 20 ng/ml urine. With the developed methods, meperidine and its metabolites in urine collected from a meperidine addict were identified and determined. Meperidine, normeperidine, meperidinic acid in free and conjugate forms, normeperidine acid in free and conjugate forms, and acetyl-normeperidine were detected. Among these metabolites, acetyl-normeperidine was reported for the first time.

Cholinesterase Inhibitors↗

PubMed1993

[Reconstruction of external ear with double-lobe skin flap].

The authors reconstructed the external ear and external auditory canal in fifty patients using double-lobe skin flap and three-point landmark method. After operation the new auricle is natural in appearance and correctly located. The hearing ability is increased in a part of patients. This article describes the method and main features of the operation.

Adolescent↗

PubMed1993

[Application of porcelain veneers].

This paper introduces the technique of porcelain veneer restoration. The retention, cosmetic effect, gingival response, type of tooth preparation and stain of porcelain veneers were discussed. 12-20 months following clinical observation of 92 cases has been undertaken. It is concluded that porcelain veneers offer the advantages of aesthetics, stain resistance, wear resistance, colour stability and soft-tissue compatibility.

Adult↗

PubMed1992

[Sampling of expiratory benzene and gas chromatography].

The method of sampling alveolar air and gas chromatography of trace benzene is reported. The lowest detectable concentration of benzene is 7.9 x 10(-4) mg/m3 in 100 ml volume. Method parameters are r = 0.999.9, mean recovery 95.14% and mean relative deviation (CV) 4.94%. 42 non-occupational and 48 occupational workers who exposed to benzene were studied by this method. The concentrations of exhaled benzene are respectively 0.016 +/- 0.011, 0.138 +/- 0.093 (before workshift) and 10.17 +/- 4.11 mg/m3 (after the end of the workshift). The results showed that this method is a simplified method for sampling alveolar air and analysis. Besides for expiratory benzene, this method can be also applied to monitoring of atmospheric trace benzene.

Benzene↗

PubMed1992

[Anodic stripping voltammetry of promethazine hydrochloride with Nafion coated glassy carbon electrode].

This paper reports the determination of promethazine hydrochloride with Nafion coated glassy carbon electrode by anodic stripping voltammetry. There is a linear relationship between the concentration and peak height in the range of 4 x 10(-8)-5 x 10(-5) mol/L and 8 x 10(-5)-1 x 10(-3) mol/L for promethazine hydrochloride. The raw material and tablets of promethazine hydrochloride have been analysed and good results were obtained.

Electrodes↗

PubMed1991

Mechanisms of tandem duplication in the Duchenne muscular dystrophy gene include both homologous and nonhomologous intrachromosomal recombination.

Three tandem duplications were previously identified in patients with Duchenne muscular dystrophy and were shown in each case to have a subset of dystrophin gene exons duplicated. The origin of these duplications was traced to the single X chromosome of the maternal grandfathers, suggesting that an intrachromosomal event (unequal sister chromatid exchange) was involved in the formation of these duplications. In the present study, a DNA segment containing the duplication junction and the normal DNA that corresponds to both ends of the duplicated region have been cloned. Subsequent mapping studies confirmed the tandem arrangement (head to tail) of these duplications and revealed their sizes to be 130 kb, approximately 300 kb, and 35-80 kb, respectively. Sequence analysis of the duplication junctions showed that one duplication was due to homologous recombination between two repetitive elements (Alu sequences) and the other two were due to recombination between unrelated nonhomologous sequences. In the latter cases, the preferred cleavage sites of the eukaryotic type I and II DNA topoisomerases were found at the junctions of these duplications, suggesting a possible role of these enzymes in the chromatid exchange events. This study provides the first insight into the molecular basis of gene duplications formed through unequal sister chromatid exchange in humans.

Base Sequence↗

PubMed1991

[Environmental and occupational exposure to benzene by investigation of expiratory benzene].

In this paper, expiratory benzene due to environmental and occupational benzene exposure during the work-shift and the morning after was studied by the analysing benzene concentrations in environmental air, in breathing air and in urinary phenol concentration. The results showed that the concentrations of expiratory benzene and urinary phenol correlated significantly with exposure to benzene. It is suggested that the expiratory benzene is a good indicator in biomonitoring of workers exposed to benzene.

Adolescent↗

PubMed1990

Duplicational mutation at the Duchenne muscular dystrophy locus: its frequency, distribution, origin, and phenotypegenotype correlation.

Partial gene deletion is the major cause of mutation leading to Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Partial gene duplication has also been recognized in a few cases. We have conducted a survey for duplication in 72 unrelated nondeletion patients, analyzed by Southern blot hybridization with clones representing the entire DMD cDNA. With careful quantitative analysis of hybridization band intensity, 10 cases were found to carry a duplication of part of the gene, a frequency of 14% for nondeletion cases (10/72), or 6% for all cases (10/181). The extent of these duplications has been characterized according to the published exon-containing HindIII fragment map, and in six of the 10 duplications a novel restriction fragment that spanned the duplication junction was detected. The resulting translational reading frame of mRNA has been predicted for nine duplications. A shift of the reading frame was predicted in four of the six DMD cases and in one of the two intermediate cases, while the reading frame remained uninterrupted in both BMD cases. RFLP and quantitative Southern blot analyses revealed a grandpaternal origin of duplication in four families and grandmaternal origin in one family. In all five families, the duplication was found to originate from a single X chromosome. Unequal sister-chromatid exchange is proposed to be the mechanism for the formation of these duplications.

Adolescent↗