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Biomedical subjects

C Huang

Publications and source records attributed to C Huang.

At least 487 records · Page 27Linked to original sources
PubMed1990

[The measurement of umbilical artery flow velocity waveforms in normal late pregnancy by Doppler ultrasound].

Doppler ultrasound was adopted in a study of fetal umbilical artery flow velocity waveforms in 81 cases of late pregnancies (28-41 gestational weeks). The peak systolic/end-diastolic ratio (A/B) and the Pourlot index were used as indices for assessing placental resistance. Both the A/B ratio (2.34 +/- 0.44) and Pourlot index (0.56 +/- 0.07) decreased while the gestational week was increasing, and they had a good correlation with the gestational week (r1 = -0.90, r2 = -0.93). The results indicated that the placental resistance became lower when the gestational week was increasing. This method has been documented a useful noninvasive technique for the exam of placental resistance.

Adult↗
PubMed1990

[Superoxide dismutase activity in tissues from 19 cases of hepatocellular carcinoma].

Superoxide dismutase (SOD) activity in hepatocellular carcinoma (HCC) tissue was studied. It was observed that activities of total SOD, Cu, Zn-SOD and Mn-SOD in HCC tissue were lower than those in normal liver tissues respectively (P less than 0.001 & 0.01 less than P less than 0.05). SOD activity in poorly differentiated HCC tissue was lower than that in well differentiated HCC tissue. Contents of copper, zinc and manganese in HCC tissues were lower than those in normal liver tissues respectively (P less than 0.001 & P less than 0.01). This study suggests that decreased content of copper, zinc and manganese may be one of the factors that lead to impairment of SOD activity. The characteristic of lower SOD activity in HCC tissue and poorly differentiated HCC tissue may be a negative regulation to limitless proliferation and poor differentiation of liver cancer cells.

Adult↗
PubMed1990

[A case of successful closure of multiple lung fistulae by omental pedicle flap after intrapleural sponge plombage 34 years before].

A case of successful closure of pulmonary fistulae by omental pedicle flap is reported. A 58-year-old female with chronic empyema as a sequela of pulmonary tuberculosis was referred with complaints of fever and purulent sputa. After extirpation of spongy "Plombs" (Vinylsponge) which had filled pleural space in previous operation done 34 years before, omental pedicle flap was fixed by sutures to multiple lung fistulae. Omental pedicle was not filled up all the empyema cavity. We anticipate that an omental pedicle flap covering the lung fistulae will be a simpler but promising method of closing lung fistulae, while simultaneously preventive of infection of residual cavity.

Chronic Disease↗
PubMed1989

Isolation and characterization of S49 mouse lymphoma cell mutants deficient in adenosine deaminase.

Adenosine deaminase-deficient mutants of a mouse lymphoma cell line S49 have been isolated by a two-step selection process. In the first step, we derived mutant lines containing haploid levels of adenosine deaminase activity from wild-type cells. The selective medium contained tritiated deoxyadenosine, deoxycytidine, and deoxycoformycin. Wild-type cells were killed, presumably because of suicidal incorporation of tritiated deoxyadenosine via the adenosine deaminase pathway. The second step was to derive, from the partially deficient mutants, sublines that were virtually lacking adenosine deaminase, using tritiated deoxyadenosine and deoxycytidine. Four mutant clones were found to contain less than 5% of the enzyme activity of wild-type cells and virtually no immunoreactive adenosine deaminase protein. Northern blot analysis showed that the levels of adenosine deaminase mRNA were drastically reduced. Back-selection for adenosine deaminase-positive revertants can be accomplished by using a medium containing deoxyadenosine (as a sole source of purine), aminopterin, and thymidine or, alternatively, by using deoxyadenosine alone in a serum-free medium.

Adenosine Deaminase↗
PubMed1989

[The use of omental pedicle flap for treatment in the field of thoracic surgery].

We present a series of 16 consecutive patients who underwent the omental pedicle flap method in the field of thoracic surgery. Fourteen of 16 patients were chronic empyema with bronchopleural fistulae and/or thoracic fistulae. A pedicle of omentum containing the right gastroepiploic artery was passed through a tunnel in the anterior diaphragm into the empyema cavity. It was fixed by mono-filament sutures on the bronchopleural fistulae. All but two patients were cured successfully by single-stage procedures. We also used a omental pedicle flap for mediastinal infection and reconstruction of the chest wall. We conclude that the use of omental pedicle flap is a promising method for treatment of serious infection in the field of thoracic surgery.

Adult↗
PubMed1988

Eutectic phase behavior of 1-stearoyl-2-caprylphosphatidylcholine and dimyristoylphosphatidylcholine mixtures.

The thermotropic behavior of aqueous dispersions of C(18):C(10)PC/diC(14)PC mixtures with different molar ratios has been investigated by high-resolution differential scanning calorimetry. C(18):C(10)PC is a highly asymmetric lipid molecule, whereas diC(14)PC is a symmetric species with the same molecular weight. Their packing properties in the bilayer are known to be similar at T greater than Tm, but very dissimilar at T less than Tm. Calorimetric results indicate that C(18):C(10)PC and diC(14)PC are completely miscible in the liquid-crystalline state. In the gel state, however, C(18):C(10)PC and diC(14)PC are only partially miscible. The temperature-composition phase diagram for C(18):C(10)PC/diC(14)PC mixtures has the shape characteristic of a typical eutectic system.

Calorimetry, Differential Scanning↗
PubMed1988

Quality improvement of sweet-potato (Ipomoea batatas L. Lam.) roots as feed by ensilage.

1. Sweet-potato (Ipomoea batatas L. Lam.) strips (SPS) mixed with maize powder (CP) in proportions 10:0, 9:1, 8:2, and 7:3 were ensiled for 1, 2 or 3 months. 2. Trypsin inhibitor activity (TIA) decreased during ensilage in samples of all treatments while the SPS-CP mixture (7:3, w/w) ensiled for 3 months contained the lowest TIA. 3. SPS-CP (8:2, w/w) dried or ensiled for 2 months, or ensiled for 2 months and dried, were each mixed with twice the amount of control diet (1:2, w/w) to make three diets. These three diets together with the control diet were used for a feeding experiment with rats to evaluate the nutritive value. 4. General composition analysis (including metabolizable energy), fatty acid composition and amino acid analysis (including percentage of essential amino acids) of the samples did not change during ensilage to an extent which could explain the improved performance of rats fed on ensiled diets. 5. Rats fed on diets containing dried SPS-CP (8:2, w/w) showed significantly lower (P less than 0.05) body-weight gain than rats fed on the control diet or ensiled SPS diets, at the end of the 8th week. They also showed enlargement of the pancreas. The adverse effect of SPS was associated with TIA which seemed to be prevented to some extent by ensilage. 6. The possibility that the starch of SPS may also contribute to the adverse effect cannot be excluded at present.

Amino Acids↗
PubMed1988

Nucleic acid hybridization for detection of cell culture-amplified adenovirus.

A number of recombinant plasmids containing genomic segments of adenovirus were constructed. Seven cloned probes, as well as total adenovirus type 2 (Ad2) and Ad16 genomic DNA, were tested by a nucleic acid hybridization technique for sensitivity and specificity in detecting adenoviruses in infected cells. Adenovirus DNA was spotted onto a nitrocellulose filter and hybridized with 32P-labeled DNA probes. The probes, total Ad2 genomic DNA, and plasmid pAd2-H (containing the hexon gene from Ad2 DNA) all detected 10 reference serotypes of five genomic subgroups (A through E) with similar sensitivities. However, plasmid pAd2-H required less preparation time than did total Ad2 DNA. Probes pAd2-F (containing the fiber gene from Ad2) and pAd16-BD (containing the BamHI D fragment from Ad16) hybridized only with reference serotypes from the homologous subgroups (C and B, respectively). Of 101 patient isolates amplified in cells, pAd2-H detected 100% of all isolates from both the homologous and the heterologous subgroups. The detection rates for pAd2-F were 100% (subgroup C) and 3.6% (subgroups A, B, and D), and those for pAd16-BD were 100% (subgroup B) and 9.4% (subgroups A, C, and D). A commercial biotinylated product (Pathogene II) was also included in this study for comparison.

Adenoviruses, Human↗
PubMed1988

Vaccinia virus recombinants expressing an 11-kilodalton beta-galactosidase fusion protein incorporate active beta-galactosidase in virus particles.

Recombinant plasmids in which vaccinia virus transcriptional regulatory sequences were fused to the Escherichia coli lacZ gene were constructed for insertion of the lacZ gene into the vaccinia virus genome. beta-Galactosidase (beta-gal) was found in some purified recombinant vaccinia virions. By enzyme activity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and microscopic techniques, the evidence suggested that beta-gal accounted for 5% of the total protein in the virion. These recombinant viruses were constructed so that a portion of the coding sequences of a late vaccinia virus structural polypeptide was fused to the amino terminus of beta-gal to produce the fusion protein. Removal of the coding sequences resulted in the complete loss of beta-gal activity. This demonstrated that a vaccinia virus DNA segment from a late structural gene is responsible for the incorporation of beta-gal into the virion.

Base Sequence↗
PubMed1988

Lacunar syndromes due to brainstem infarct and haemorrhage.

Nine patients with brainstem infarct and two with brainstem haemorrhage presented with pure motor stroke, pure supranuclear facial palsy, sensorimotor stroke or ataxic hemiparesis. Despite the clinical similarity with hemispheric lacunes, brainstem infarcts causing lacunar syndromes probably have a greater tendency to progress. Small brainstem haemorrhages should also be considered as a cause of lacunar syndromes and the difficulty in differentiating them from small infarcts without CT is emphasised.

Aged↗
PubMed1987

Characterization of the cell surface heterodimer VLA-4 and related peptides.

A monoclonal antibody (B-5G10) was produced which specifically recognizes the Mr 150,000/130,000 VLA-4 complex on the surface of human cells. Cross-linking studies indicated that the Mr 150,000 alpha 4 subunit of VLA-4 is in noncovalent 1:1 association with the Mr 130,000 VLA beta subunit. In the absence of cross-linking, the VLA-4 alpha 4 beta subunit complex was easily dissociated, especially in Nonidet P-40 detergent, or at elevated pH (above 8.0). Studies of dissociated subunits showed that B-5G10 recognizes an epitope on the Mr 150,000 alpha 4 subunit of VLA-4, whereas the beta subunit is immunologically identical to the Mr 130,000 beta subunit common to all VLA heterodimers. VLA-4 is widely distributed on hematopoietic cells, including thymocytes, peripheral blood lymphocytes, monocytes, activated T cells, T and B lymphoblastoid cell lines, and myeloid cell lines. However, VLA-4 is only weakly expressed on most adherent cell lines tested. Immunoprecipitates of VLA-4 often contain additional proteins of Mr 80,000 and Mr 70,000. These are probably derived from the Mr 150,000 alpha 4 subunit because: 1) they are both recognized by anti-alpha 4 sera, but not anti-beta sera; 2) the sum of their sizes is equal to the size of alpha 4; 3) they are selectively coexpressed with alpha 4 and not other VLA alpha subunits; 4) the Mr 80,000 protein has an identical NH2-terminal sequence to alpha 4; 5) like alpha 4, the Mr 70,000 and 80,000 peptides can variably associate with the VLA beta subunit; and 6) trypsin appears to cleave the Mr 150,000 alpha 4 subunit into products of Mr 70,000 and 80,000.

Amino Acid Sequence↗
PubMed1987

The VLA protein family. Characterization of five distinct cell surface heterodimers each with a common 130,000 molecular weight beta subunit.

The family of human cell surface heterodimers which includes VLA-1 and VLA-2 is now shown to include three additional heterodimers, here called VLA-3, VLA-4, and VLA-5. Each of these separate VLA structures is composed of a distinct alpha subunit (Mr 110,000-200,000 nonreduced) noncovalently associated with a common beta subunit (Mr 110,000 nonreduced). Chemical cross-linking experiments provided evidence that each VLA complex exists predominantly as a 1:1 alpha beta heterodimer. The VLA proteins are widely distributed, with one or more of the heterodimers present on nearly all cell types tested. Evidence for five distinct VLA alpha subunits was obtained from differences observed in antibody recognition, cell distribution patterns, two-dimensional gel analyses, and V8 protease cleavage patterns. On the other hand, the beta subunit present in each heterodimer was immunochemically and electrophoretically indistinguishable, and yielded identical V8 cleavage fragments. Immunoblotting experiments revealed that besides the Mr 110,000 beta normally seen, another beta protein was present that is smaller in size (Mr 90,000 nonreduced), altered or deficient in glycosylation, and not available for cell surface radiolabeling.

Antibodies, Monoclonal↗
PubMed1987

Kinetics of allophycocyanin's trimer-monomer equilibrium.

Kinetic studies of the dissociation of allophycocyanin trimers to monomers have been performed by using stopped-flow techniques. The dissociation was monitored by two techniques: by light scattering to observe the molecular weight changes directly and by 650-nm absorbance to observe the linkage of quaternary structure to spectra. The light-scattering experiments showed a simple exponential decay of trimers to monomers with a dissociation constant of 0.23 s-1. The absorption changes were complex, with two processes occurring. The faster absorption change appeared to be almost simultaneous with the molecular weight change (about 0.27 s-1) and was perhaps totally coordinated with it. The slower absorption change (0.071 s-1) was possibly a result of a conformational change in the chromophore arising during the conversion from newly dissociated monomers to equilibrium monomers.

Cyanobacteria↗
PubMed1987

Use of the monoclonal antibody 12F1 to characterize the differentiation antigen VLA-2.

A monoclonal antibody, 12F1, has been produced that specifically immunoprecipitates the human cell surface structure VLA-2 from platelets and long-term activated T cells, as well as from fibroblast and neuroblastoma cell lines. Cross-linking studies indicate that the VLA-2 structure exists on the cell surface as a 165,000 Mr heavy chain (alpha 2) in noncovalent 1:1 association with a 130,000 Mr light chain (beta). The monoclonal antibody A-1A5, which reacts with the beta subunit common to all VLA structures, was able to completely preclear VLA-2, indicating that all of the alpha 2 subunit was associated with VLA beta-chain. The specificity of 12F1 for VLA-2 allowed independent immunoprecipitation and flow cytometry analysis of this alpha 2 beta structure separate from any other VLA structures that may have been present such as VLA-1 or free beta-subunit. Subunit dissociation studies were used to demonstrate that 12F1 recognizes an epitope on the alpha 2 chain on VLA-2, which is consistent with the 12F1 specificity for VLA-2 alone among the VLA proteins. Analysis of activated T cells indicated that VLA-2, like VLA-1, is another "very late" appearing T cell activation antigen that arises concurrently with VLA-1 starting at day 7 and increasing through 2 wk. VLA-2 was found on many of the same cells as VLA-1 (inactivated T cells, T cell leukemia cells, fibroblasts, SK-N-SH neuroblastoma cells), but VLA-1 and VLA-2 can be expressed independently, because VLA-2 was also present on VLA-1-negative cells such as HSB and platelets, and VLA-1 was present on VLA-2-negative C8215 cells.

Antibodies, Monoclonal↗