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Biomedical subjects

Y Xiang

Publications and source records attributed to Y Xiang.

At least 109 records · Page 6Linked to original sources
PubMed1995

[Mosaicism confined to placenta in pregnancies with adverse outcome].

Chorionic villi and fetal tissues from 50 pathological human conceptions at gestational weeks 9-40 were cultured and cytogenetically analyzed to explore the existence of chromosomal mosaicism confined to the extraembryonic tissues and to clarify the relationship between confined placental mosaicism and adverse outcome of pregnancy. Chorionic villi and fetal tissues from 12 second trimester gestations terminated served as a control group. In two pathological gestations true mosaicism was found exclusively in chorionic cells and could not be confirmed in cells derived from the fetal tissues. One of these was severely growth retarded. Concordant results were obtained in all other cases.

Adult↗
PubMed1995

Abdominal scar endometriosis: report of 28 cases.

Twenty-eight cases of abdominal scar endometriosis from January, 1980 to December, 1993 are reported. Of these patients, twenty-four underwent term cesarean section, and four underwent a midtrimester abortion by abdominal hysterotomy. The majority of patients manifested symptoms 1 year after the operation. The most common was a painful mass of scar tissue that became swollen and tender during menstruation. The pathogenesis, diagnosis and treatment are discussed. In correlation with the pathological findings, the effects of drug therapy are evaluated. It was found that surgical excision is the best method of treatment.

Abdominal Muscles↗
PubMed1995

[Technology of processing carbonized root of Sanguisorba of ficinalis L. and the quality standards for its prepared pieces].

The technology of processing carbonized root of Sanguisorba of ficinalis was selected using orthogonal experiment design. The result shows that the best way is to stir-fry the drug in a pan for 7.5 min at 250 degrees C. The contents of trace elements in the prepared piece are significantly increased, and the prepared piece have marked hemostatic and bacteriostastic effects.

Animals↗
PubMed1994

Fluorescence in situ hybridization with a chromosome 21-specific cosmid contig: 1-day detection of trisomy 21 in uncultured mesenchymal chorionic villus cells.

We present a modified, fast trisomy 21 detection assay using fluorescence in situ hybridization (FISH) on uncultured mesenchymal chorionic villus cells. The whole test takes about 24 h. We used a cosmid contig as a probe and modified an in situ sample preparation method first described by Klinger et al. (1992). The assays saves time and cost of culture in comparison with a previously described trisomy 21 detection FISH assay (Bryndorf et al., 1993). A small blind clinical study comparing the modified and the previously described FISH assays using mesenchymal chorionic villus cells showed comparable results and concordance with conventional cytogenetic analysis. The frequency of nuclei with three hybridization signals from samples disomic for chromosome 21 ranged from 0 to 8 per cent with both assays, while trisomic samples had 60-80 and 54-90 per cent of the mesenchymal nuclei with three signals in the modified and previously described assays, respectively. Normal (disomic) and trisomic mesenchymal chorionic villus samples can be distinguished clearly and rapidly without culture in the modified assay.

Base Sequence↗
PubMed1994

An assembly domain of the Rous sarcoma virus Gag protein required late in budding.

The Gag protein of Rous sarcoma virus has the ability to direct particle assembly at the plasma membrane in the absence of all the other virus-encoded components. An extensive deletion analysis has revealed that very large regions of this protein can be deleted without impairing budding and has suggested that the essential functions map to three discrete regions. In the studies reported here, we establish the location of assembly domain 2 (AD2) within the proline-rich p2b sequence of this Gag protein. AD2 mutants lacking the p2b sequence were completely defective for particle release even though their Gag proteins were tightly associated with the membrane fraction and exhibited high levels of protease activity. Mutations that inactivate the viral protease did not restore budding to wild-type levels for these mutants, indicating that the defect is not due simply to a loss of protease regulation. AD2 mutants could be rescued into dense particles in genetic complementation assays, indicating that their defect is not due to a gross alteration of the overall conformation of the protein and that the assembly function is not needed on every Gag molecule in the population. Several mutants with amino acid substitutions in the p2b sequence were found to have an intermediate capacity for budding. Inactivation of the protease of these mutants stabilized the Gag polyprotein within the cells and allowed an increase in particle release; however, the rate of budding remained slow. We favor the idea that AD2 is a dynamic region of movement, perhaps serving as a molecular hinge to allow the particle to emerge from the surface of the cell during budding.

Amino Acid Sequence↗
PubMed1994

[Grouped Cox regression model and its application in study of prognostic factors on cancer].

Cox proportional hazards regression model is the most popular multivariate regression model for analysis of survival data in medical follow-up studies and clinical trials, but it is unable to handle grouped survival data or large data sets with many tied failure times adequately. This paper explores the grouped proportional hazards regression model (GPH model) and its use in analysis of large data sets presented in life tables. By use of the data in a lung cancer follow-up study conducted in urban area of Shanghai, the authors give an example in detail for analysing prognostic factors of lung cancer by using GLIM.

Adult↗
PubMed1993

Prenatal diagnosis by in situ hybridization on uncultured amniocytes: reduced sensitivity and potential risk of misdiagnosis in blood-stained samples.

Maternal cell contamination was assessed in 18 macroscopically blood-stained amniotic fluid samples from male fetuses. The samples were analysed by double-target fluorescent in situ hybridization (ISH) with Y and X chromosome-specific probes. The only sample with an aberrant karyotype (47,XY, + 18) was also analysed by hybridization with a chromosome 18-specific probe. An interpretation of extensive maternal cell contamination was made in two samples, one of which was the sample with trisomy 18. ISH with the chromosome 18-specific probe on this latter sample showed that the sensitivity of the ISH method for chromosome enumeration of uncultured amniotic fluid samples may be reduced in blood-stained samples. It was calculated that by using ISH for chromosome enumeration of the two extensively contaminated samples, a case of trisomy 21 might have been overlooked in both samples, while a case of trisomy 18 might only have been overlooked in one of the samples. It is concluded that ISH should not be used for chromosome enumeration of uncultured amniotic fluid samples that are macroscopically blood-stained without further technical developments.

Amniotic Fluid↗
PubMed1993

Rapid detection of numerical aberrations of chromosomes 13, 18 and 21 in chorionic mesenchymal cells.

We have devised and evaluated a rapid screening method for the detection of numerical aberrations of chromosomes 13, 18 and 21 in chorionic villus cells. We used non-radioactive in situ hybridization (ISH) with three chromosome-specific probes on overnight-attached mesenchymal cells from chorionic villi. A blind study was performed of 47 karyotypically normal samples, one triploid sample, two samples trisomic for chromosome 21, and two samples from a fetus with putative mosaicism (46/47, +21). All samples were hybridized with the chromosome 18- and 21-specific probes. Thirty samples were additionally hybridized with the chromosome 13-specific probe. The test could be completed within 3-4 days of sampling. In samples disomic with respect to the probed chromosomes, an average of 2 per cent (range 0-9 per cent) had three hybridization signals. By contrast, in the samples trisomic for the probed chromosome(s), 57 per cent (chromosome 13), 51 per cent (chromosome 18), and an average of 74 per cent (55-86 per cent) (chromosome 21) of the nuclei exhibited three signals. In the putative mosaic samples, the number of nuclei with three chromosome 21-specific signals ranged from 41 to 69 per cent. We conclude that this technique rapidly and clearly distinguishes between normal and trisomic/triploid samples, and consequently may be of use in future prenatal diagnosis.

Chorionic Villi↗
PubMed1993

Multiply sectioned Bayesian networks for neuromuscular diagnosis.

A prototype neuromuscular diagnostic system (PAINULIM) that diagnoses painful or impaired upper limbs has been developed based on Bayesian networks. This paper presents nonmathematically the major knowledge representation issues that arose in the development of PAINULIM. Motivated by the computational overhead of large application domains, and the desire to provide a user with an interface that gives a focused display of a subdomain of current interest, we built PAINULIM using the idea of multiply sectioned Bayesian networks. A preliminary evaluation of PAINULIM with 76 patients has demonstrated good clinical performance.

Artificial Intelligence↗
PubMed1993

A study and analysis of the deaths due to advanced Schistosoma japonicum infection in the Dongting Lake area of China.

This study collected records of 245 cases of death due to advanced schistosomiasis japonica in the eastern Dongting Lake area between 1985 and 1990. The mean survival of the patients was 5.16 years. The patients with ascitic type had a shorter expected life while the life span of splenomegalic type patient markedly improved after splenectomy. The HBsAg positive rate was 43.64%; the rate of those complicated with carcinoma of liver was 19.18%. The latter group had a HBV infection rate as high as 61.70%.

Adolescent↗
PubMed1992

Quality control in nerve conduction studies with coupled knowledge-based system approach.

Contemporary equipment used for nerve conduction studies is usually capable of computerized measurement of latency, amplitude, duration, and area of nerve and muscle action potentials and resulting conduction velocities. Abnormalities can be due to technical error or disease. Identification of technical error is a major element of quality control in electromyography, and artificial intelligence could be useful for this purpose. We have developed a coupled knowledge-based prototype system (QUALICON) to assess the correctness of recording and stimulating characteristics in routine conduction studies. QUALICON extracts numeric features from CMAPs or SNAPs, which are translated into symbolic form to drive a Bayesian network. The network uses high-level knowledge to infer the quality of stimulating and recording electrode placement as well as polarity and stimulus strength making recommendations as to the likely technical error when abnormal potentials are detected. A preliminary assessment shows that QUALICON performs as well as manual assessment performed by professionals.

Action Potentials↗
PubMed1992

[Nosocomial infections of methicillin-resistant Staphylococcus aureus and their detection].

In 142 strains of Staphylococcus aureus randomly isolated from clinical samples in a year, methicillin-resistant Staphylococcus aureus (MRSA) accounted for 79.6% (113/142). MRSA in the samples from the respiratory, burning and hematological departments came to 92.0% (23/25), 84.6% (11/13) and 83.3% (30/36) in proportion respectively. 79.6% of MRSA strains were isolated from the patients in whom the infections were confirmed to be hospital-acquired. All the strains of Staphylococcus aureus examined were resistant to penicillin G and ampicillin, but sensitive to vancomycin. Twenty hospital-acquired strains of MRSA showed a resistance to all detected antibiotics (multi-drug resistance, MDR), but vancomycin; strains of methicillin-sensitive ones, however, showed on MDR. In 45 strains of Staphylococcus aureus isolated from swabs of fingers of 62 medical workers, 31 (68.9%) were methicillin-resistant. The resistant similarity of shares of strains between medical staff and patients indicated a potential role that medical workers play in spread of nosocomial infections.

Cross Infection↗
PubMed1990

[Dissolution of metronidazole stilus].

Metronidazole stilus is a new preparation to be inserted into periodontal pockets for treatment of periodontitis. The certificate and file number of approval given to this new product were issued by the Ministry of Public Health in August, 1989. Its shape looks like a toothpick and the width, thickness and length are 1.5mm, 0.7mm and 3 cm, respectively. The content of metronidazole in each cm of the stilus is 2.2 mg. We have studied the dissolution of the new preparation by rotation basket method. The kinetic process of dissolution approximates first order kinetics. The K, t0.5 and t0.9 are 0.0624 min-1, 12.8 and 38.6 minutes, respectively. The requirement is that the dissolved percentage should not be lower than 60% of the added amount in 30 minutes. In order to have a dissolution test similar to that of the stilus in dental pockets, we examined the dissolution in static condition. The results showed that a very high dissolution rate appeared in the beginning, but it decreased quickly, and 71.76% of metronidazole was not dissolved until 48 hours. So one insertion per two days for clinical use is suggested.

Metronidazole↗
PubMedDate not supplied

Targeted gene conversion in a mammalian CD34+-enriched cell population using a chimeric RNA/DNA oligonucleotide.

Gene conversion of genetically inherited point mutations is a fundamental methodology for treating a variety of diseases. We tested the feasibility of a new approach using an RNA/DNA chimeric oligonucleotide. The beta-globin gene was targeted at the point mutation causing sickle cell anemia. The chimera is designed to convert an A residue to a T after creating a mismatched basepair. In a CD34+-enriched population of normal cells a 5-11% conversion rate was measured using restriction enzyme polymorphism and direct DNA sequence analyses. The closely related delta-globin gene sequence appeared unchanged despite successful conversion at the beta-globin locus.

Antigens, CD34↗
PubMedDate not supplied

Immune function, hepatic CYP1A, and reproductive biomarker responses in the gulf killifish, Fundulus grandis, during dietary exposures to endocrine disrupters.

The gulf killifish, Fundulus grandis, was used to determine the influence of biological rhythms on three biomarker responses. We first developed monoclonal antibodies against the model's immunoglobulins and vitellogenin in order to measure antibody responses and vitellogenesis, respectively. We then treated adults with 10, 1, 1, and 10 ppm of Aroclor 1254, tribuyltin, 3-methylcholanthrene, and nonyl-phenol, respectively, in mixtures over a 16-week period. The study followed Vibrio anguillarum-specific antibody responses, hepatic CYP1A, and plasma vitellogenin levels in the morning and again in the evening at 2-week intervals. The contaminated diet suppressed secondary antibody responses, but only in the morning. The contaminated diet also altered CYP1A, but not vitellogenesis. In addition, fish in the control group exhibited daily and seasonal differences in specific antibody levels and CYP1A induction. Moreover, circulating vitellogenin levels in control males sampled in the morning increased throughout the exposure, but remained below those of females. This study underscores the need to consider normal physiological rhythms when employing biomarkers in toxicology.

Animals↗
PubMedDate not supplied

Identification and preliminary validation of novel biomarkers of acute hepatic ischaemia/reperfusion injury using dual-platform proteomic/degradomic approaches.

Hepatic ischaemia/reperfusion (I/R), a major cause of liver damage associated with multiple trauma, haemorrhagic and septic shock, and liver transplantation, contributes significantly to multiple organ failure. Development of novel sensitive biomarkers that detect early stages of liver damage is vital for effective management and treatment of ischaemic liver injury. By using high-throughput immunoblotting and cation-anion exchange chromatography/reversed-phase liquid chromatography-tandem mass-spectrometry, we identified several hepatic proteins, including argininosuccinate synthase (ASS) and estrogen sulfotransferase (EST-1), which were degraded in the liver and rapidly released into circulation during I/R injury. ASS accumulated in serum within 10 min, reached a steady state at 30 min, and persisted up until 3 h after reperfusion following 30 min of total hepatic ischaemia. EST-1 appeared rapidly in blood and attained maximum within 1 hour followed by a decline at 3 h of reperfusion. No ASS or EST-1 protein was detected in serum of control or sham operated rats. ASS and EST-1 exhibited greater sensitivity and specificity toward I/R liver injury as compared with alanine aminotransferase (ALT), an established marker of hepatocellular necrosis. In contrast, serum ASS and EST-1 were undetectable in rats with chronic alcoholic liver disease, while the levels of ALT protein were significantly increased. In addition, ASS, but not EST-1 or ALT accumulated in blood only 6 h after treatment with hepatotoxic combination of lipopolysaccharide and D-galactosamine. These data demonstrate the utility of ASS and EST-1 as novel sensitive and specific biomarkers of acute liver ischaemic injury for prospective clinical studies.

Animals↗