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Biomedical subjects

Y X Huang

Publications and source records attributed to Y X Huang.

At least 19 recordsLinked to original sources
PubMed1992

Identification and quantitation of HIV-1 in the liver of patients with AIDS.

OBJECTIVE: To detect and quantify HIV-1 in the liver in vivo. DESIGN: Fourteen liver biopsy samples and corresponding blood lymphocytes and monocytes from patients with AIDS were studied for HIV-1 using quantitative polymerase chain reaction (PCR). In addition, expression of HIV-1 antigen and messenger (m) RNA in 10 autopsy liver specimens was examined by immunohistochemistry and in situ hybridization. RESULTS: The amount of HIV-1 DNA in nine liver samples ranged from 850 to 27,000 copies per 10(6) cells, with mean and median values of 8150 and 3500 copies per 10(6) cells, respectively. Five other samples had no detectable HIV-1 DNA by PCR. Intracellular expression of HIV-1 antigen and mRNA was also detected in both Kupffer cells and hepatocytes by in situ studies. CONCLUSION: These findings strongly indicate that HIV-1 could replicate in the liver of a majority of patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Virions of primary human immunodeficiency virus type 1 isolates resistant to soluble CD4 (sCD4) neutralization differ in sCD4 binding and glycoprotein gp120 retention from sCD4-sensitive isolates.

Primary isolates of human immunodeficiency virus type 1 (HIV-1) are much less sensitive to neutralization by soluble CD4 (sCD4) and sCD4-immunoglobulin (Ig) chimeras (CD4-IgG) than are HIV-1 strains adapted to growth in cell culture. We demonstrated that there are significant reductions (10- to 30-fold) in the binding of sCD4 and CD4-IgG to intact virions of five primary isolates compared with sCD4-sensitive, cell culture-adapted isolates RF and IIIB. However, soluble envelope glycoproteins (gp120) derived from the primary isolate virions, directly by detergent solubilization or indirectly by recombinant DNA technology, differed in affinity from RF and IIIB gp120 by only one- to threefold. The reduced binding of sCD4 to these primary isolate virions must therefore be a consequence of the tertiary or quaternary structure of the envelope glycoproteins in their native, oligomeric form on the viral surface. In addition, the rate and extent of sCD4-induced gp120 shedding from these primary isolates was lower than that from RF. We suggest that reduced sCD4 binding and increased gp120 retention together account for the relative resistance of these primary isolates to neutralization by sCD4 and CD4-IgG and that virions of different HIV-1 isolates vary both in the mechanism of sCD4 binding and in subsequent conformational changes in their envelope glycoproteins.

Amino Acid Sequence↗
PubMed1991

[Small bowel transit time measured with native lactulose breath hydrogen test].

Native lactulose was used in breath hydrogen test (BHT) to detect small bowel transit time (SBTT) in normal persons (34 cases) and patients with functional diarrhea (24 cases) and functional constipation (12 cases). The mean SBTT was 80.6 +/- 28.3 min, 58.4 +/- 42.2 min and 104.2 +/- 21.0 min respectively. When the mean SBTT in the patient groups was compared with that in the normal group, there was statistically significant difference (P less than 0.05 and 0.01 respectively). The results showed that native lactulose produces hydrogen successfully (94.3%). Few side-effects were found, if a dose of 10g was used.

Adolescent↗
PubMed1990

Augmentation of various immune reactivities of tumor-bearing hosts with an extract of Cordyceps sinensis.

In order to enhance general reactivity of immune system in the tumor-bearing host, we employed extract of Cordyceps sinensis (CSE) as a biological response modifier. Cordyceps sinensis is an interesting material produced by a kind of mushroom parasitic to larval moths and was used to hasten recovery from exhaustion in ancient China. In this experiment, C57BL/6 mice implanted subcutaneously with syngeneic EL-4 lymphoma cells were employed as the host. Oral administration of the extract leads to a reduction of tumor size and prolongation of the host survival time. As judged by plaque-forming cells against T-dependent (sheep erythrocytes) and T-independent (bacterial lipopolysaccharide) antigens, CSE showed to augment the antibody responses. As for the activities of peritoneal macrophages, chemotaxis was dramatically depressed within a few days after EL-4 transplantation up to the end of life, but treatment with CSE at -14, -7, -4, +4, +7 and +10 days after the tumor transplantation augmented the activity about four times stronger than that of control. Phagocytic activity of macrophages was also decreased in tumor-bearing mice treated with cyclophosphamide (100 mg/kg) 3 and 5 days after tumor transplantation. But administration of CSE restored the activity to more than the normal level. The overall efficacy of CSE was tested with protective activity against systemic infection by Salmonella enteritides. The tumor-bearing mice receiving this medicine lived significantly longer than any other groups without CSE.

Administration, Oral↗
PubMed1990

Sulcus topography of the parietal opercular region: an anatomic and MR study.

The study describes the sulcal and gyral topography, variability, and left-right asymmetry of the parietal operculum. Eighty postmortem hemispheres as well as sagittal magnetic resonance images from 20 health volunteers (40 hemispheres) were evaluated. Four different types of parietal opercular sulcus topography were recognized. Most frequently, and conforming with the anatomic "textbook pattern", the inferior postcentral sulcus (POCS) is the sulcus anterior to the posterior ascending ramus (PAR) of the Sylvian fissure (type 1). Variations were the following: lack of a PAR (type 2), interposition of an intermediate opercular sulcus and gyrus between PAR and POCS (type 3), and direct transition of PAR into POCS with subsequent lack of a classical supramarginal gyrus (type 4). Inconstancy of the sulcal standard arrangement was especially pronounced among left hemispheres, where the patterns differed from type 1 in one third of the cases. Types 2 and 3 were significantly more frequent in left hemispheres, whereas type 4 occurred significantly more frequently in right hemispheres. Upon intraindividual left-right comparison, a remarkable 38% of the brains showed gross asymmetry of the parietal opercular sulcus patterns, characterized by a left type 2 or 3 and/or a right type 4; another 5% exhibited a reverse type of asymmetry. The findings supplement previous data on gross variability and left-right asymmetry of the posterior Sylvian fissure and its lower bank. They indicate that the Sylvian fissure is an unreliable landmark with respect to inferior parietal structures especially in left hemispheres. Individual mapping of perisylvian topography may contribute to studies on structural-functional relationship.

Adult↗
PubMed1990

Total surface of temporoparietal intrasylvian cortex: diverging left-right asymmetries.

Measurements of the total convoluted surface area of cortex buried in the temporoparietal transition of the Sylvian fissure were performed using "three-dimensional" magnetic resonance morphometry in 10 randomly selected human cadaver brains. The measurements comprised the planum temporale, which covers the superior temporal gyrus posterior to Heschl's first transverse gyrus, and the caudally adjacent walls of the descending and ascending rami of the Sylvian fissure. Also, the total convoluted surface of the planum temporale was compared with its superficially exposed surface as determined by photographical planimetry after brain section, so that the index of cortical folding of the planum temporale could be estimated. The following results were obtained: Cortical folding of the planum temporale did not differ significantly between left and right hemispheres (p greater than .6). The total and the superficially exposed surface of the planum temporale showed significant leftward asymmetry (p less than or equal to .0078). In contrast, the total surface of cortex buried in the caudal segments of the Sylvian fissure posterior to the planum exhibited significant rightward asymmetry (p less than or equal to .016). The combined cortical surface area buried in the whole posterior Sylvian fissure caudal to the first transverse gyrus did not show significant left-right asymmetry (p greater than 0.3). The data suggest divergent lateral asymmetries in the posterior intrasylvian region with excesses of superior temporal cortex in left hemispheres and of supramarginal cortex in right hemispheres.

Aged↗
PubMed1990

CD4-independent, productive human immunodeficiency virus type 1 infection of hepatoma cell lines in vitro.

Five hepatoma cell lines, including CZHC/8571, PLC/PRF/5, Hep3B, HepG2, and HUH7, were inoculated with three diverse isolates of human immunodeficiency virus type 1 (HIV-1). Productive infection was noted in all hepatoma cell lines, and expression of viral p24 antigen lasted for over 3 months, but its level decreased in proportion to the number of viable cells. HIV-1 antigens were also found in the cells by immunohistochemical staining and radioimmunoprecipitation assay, as were viral RNA by in situ hybridization and HIV-1-like particles by electron microscopy. Virus yield assays were also positive on supernatant fluids collected from hepatoma cultures inoculated with HIV-1. Despite their susceptibility to infection, all five hepatoma cell lines were negative for CD4 by immunofluorescence and for CD4 mRNA by slot-blot hybridization. In addition, HIV-1 infection of hepatoma cell lines was not blocked by anti-CD4 monoclonal antibody or soluble CD4. Together, these findings clearly demonstrate that all five hepatoma cell lines were susceptible to productive infection by HIV-1 in vitro via a CD4-independent mechanism.

CD4 Antigens↗
PubMed1990

Synthesis of a recombinant DNA-derived HBV e antigen and its application in diagnosis.

The gene coding for HBV e antigen (HBeAg) and core antigen (HBeAg) are located in the C region of the HBV genome. In this paper 1.8 kb BamHI-EcoRI DNA fragment carrying HBc gene from adw2 HBV DNA was digested with Bal31 and HapII, a series of fragment with different length were produced and inserted into pUR222 and pUC18 vectors to construct various recombinant plasmids. Two new recombinants able to direct high level synthesis of HBeAg in E. coli were obtained. Recombinant HBeAg was then purified by DEAE chromatography and affinity chromatography. The preparation obtained were identified by electrophoresis and immunochemical analysis. Molecular weight of the recombinant HBeAg determined by SDS-PAGE was about 38 kd. It is considered to be a dimer of two fused antigen molecules in size of 19 kd. Bacterial extracts prepared from cells harboring one of the constructed plasmids have been used successfully as a diagnostic reagent for the detection of HBeAg and anti-HBe in human sera by ELISA.

Cloning, Molecular↗
PubMed1990

[Clinical observations on the treatment of hookworm, Ascaris and Trichuris infection with oxibendazole].

340 cases of hookworm infection, 196 cases of ascariasis and 178 cases of trichuriasis were treated with an anthelmintic, oxibendazole, 15mg/kg.d x 3d; 102, 70 and 66 cases of respective infections were treated with pyrantel 10mg/kg.d x 3d and 108, 74 and 63 cases took placebo for comparison and as control under double-blind observations. Re-examinations of the stool were performed after the treatment. Among the cases treated with oxibendazole, the egg negative conversion rates of hookworm, Ascaris and Trichuris were 70.3-80.6%, 92.5-97.8 and 67.0-71.0% respectively. The egg reduction rates of hookworm were 98.1-98.6%. The larval negative conversion rates of Ancylostoma duodenale and Necator americanus were 77.7 and 83.2% respectively. Among the cases treated with pyrantel, the egg negative conversion rates of the three above mentioned parasites were 73.5, 90.0 and 28.8% respectively. The egg reduction rate of hookworm was 98.8%. Among the cases treated with placebo, the egg negative conversion rates of the three above mentioned parasites were 6.5, 29.7 and 7.9%. No marked adverse reactions were observed by clinical and laboratory examinations.

Animals↗
PubMed1989

Topography and identification of the inferior precentral sulcus in MR imaging.

Sagittal MR imaging was used to investigate cerebral sulci bordering the functionally important areas on the lateral suprasylvian surface. The aim of the study was to identify characteristic relationships of the inferior precentral sulcus to nearby sulci and gyri. MR findings in 20 healthy volunteers were compared with those in 62 intact postmortem hemispheres. MR techniques are described for the direct identification of the anterior ascending ramus of the sylvian fissure and the inferior precentral sulcus. These sulci, which border Broca's area and the primary motor area, can be reliably identified with sagittal MR. Four different types of sulcus topography were recognized. Most frequently, the inferior precentral sulcus is the sulcus posterior to the anterior ascending sylvian ramus (95% in the MR study, 87% in the anatomic study). Occasionally, an additional sulcus is interposed (5%, 10%), or an ascending ramus is absent (0%, 3%). Identification of these landmarks is important for the exact preoperative localization of cortical lesions as well as for the intraoperative interpretation of individual sulcus patterns.

Adult↗
PubMed1987

Determination of artemether in plasma and whole blood using HPLC with flow-through polarographic detection.

An HPLC method with polarographic detection for the trace determination of artemether in plasma and whole blood was developed and applied to pharmacokinetic and clinical pharmacological studies. The method showed high sensitivity and selectivity because of the easy reduction of the peroxide linkage of artemether at the mercury drop electrode. The detection limit was 10 ng and the detector response was linear over the range of 10 ng to 1 microgram artemether injected onto the column. The largest relative standard deviation of 10 replicate measurements of standard solutions (concentrations of 10 ng/mL-1 microgram/mL) was 8%. The recovery from whole blood and plasma of added drug (concentrations of 15-480 ng/mL) was 71-100%.

Animals↗
PubMed1987

Simple and sensitive CO2 laser visual screen.

The present paper describes a simple and sensitive CO2 laser visual screen which is made from silica gel with cobalt chloride as indicator. The screen can directly and almost immediately display a clear mode pattern of an exposing CO2 laser beam, it can respond to laser intensities ranging from 80 mW/cm2 to 26 W/cm2. It is suitable for the observation of both high-power lasers, which are used for surgery, and very low power ones, which are used for biostimulation.

Carbon Dioxide↗
PubMed1987

Serum interferon in systemic lupus erythematosus.

Serum interferon levels were estimated in 67 samples obtained from 47 patients with SLE. Levels were increased in 70% of the samples and 72% of the patients. In the patients with active disease 81% had increased interferon levels, while in the group with clinically quiescent disease 10% had increased levels. In 20 patients retested 3 1/2 months after treatment the changes in interferon levels tended to parallel the changes in clinical disease activity in 80% of cases. Patients with active skin lesions, arthritis, and renal or haematopoietic involvement tended especially to have increased interferon levels. Interferon levels were directly related to ANA titre and inversely related to serum C3 levels, but not related to serum levels of circulating immune complexes or immunoglobulin. The interferon was shown to be of type alpha. The interferon level can be regarded as one of several parameters reflecting disease activity and may also be related to the prognosis. As it is possible that interferon may be a direct mediator of the pathophysiology of auto-immune disease, we do not recommend the use of interferon or its inducers in the therapy of SLE.

Adolescent↗
PubMed1983

Comparison of the lipoprotein gene among the enterobacteriaceae. DNA sequence of Morganella morganii lipoprotein gene and its expression in Escherichia coli.

A DNA sequence of 532 base pairs encompassing the entire Morganella morganii lipoprotein gene (lpp) was determined. Sequence comparisons of the M. morganii lpp gene with the lpp genes from Escherichia coli, Serratia marcescens, and Erwinia amylovora reveal that the M. morganii lpp gene is more distantly related to the E. coli lpp gene than any of the other lpp genes examined. Between the E. coli and M. morganii lpp genes, the following homologies were found: 44% in the promoter region (bases, -45 to -1), 88% in the 5'-end untranslated region of the mRNA, 58% in the signal sequence coding region, 75% in the coding region for the first 51 and 43% for the last 7 amino acid residues. Upstream of the promoter region and downstream of the termination codon, there are extensive insertions, deletions, and base substitutions. In spite of the differences in the DNA sequences, the lipoprotein structure was found to be highly conserved except for the carboxyl-terminal sequence of 7 amino residues. The coding region of the M. morganii lpp gene including the signal sequence was inserted into an expression cloning vector so that the production of the M. morganii lipoprotein could be induced in E. coli by a lac inducer, isopropyl-beta-D-thioglactoside. It was found that when induced, the M. morganii prolipoprotein was apparently secreted normally across the E. coli cytoplasmic membrane, modified with glycerol and palmitic acid, processed to the mature lipoprotein, and assembled in the E. coli outer membrane. The bound form covalently linked to the peptidoglycan was also found.

Base Sequence↗