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Biomedical subjects

W Huang

Publications and source records attributed to W Huang.

At least 649 records · Page 36Linked to original sources
PubMed1986

Purification and properties of epithelial growth inhibitor (EGI) from human platelets: its separation from type beta transforming growth factor (TGF-beta).

We previously reported that sera from various kinds of animals contain a protein(s) capable of inhibiting the growth of the non-malignant epithelial cell line derived from Buffalo rat liver (BRL). In the present study, a similar epithelial cell-specific growth inhibitor (EGI) was purified to homogeneity from an acid-ethanol extract of human platelets. During purification, EGI was separated from the major component of type beta transforming growth factor (TGF-beta), which can stimulate the colony formation of the non-malignant fibroblastic cell line derived from rat kidney (NRK) in soft agar in the presence of epidermal growth factor (EGF). The purified EGI had an Mr of 27,000, and was composed of two subunits identical in Mr. It significantly inhibited the growth in monolayer cultures of three non-malignant epithelial cell lines, BRL, MDCK (from Madin-Darby canine kidney) and BSC-1 (from African green monkey kidney), at doses lower than 40 pg/ml in medium containing 10% fetal calf serum. Its inhibitory activity was stable against heating at 90 degrees C for 3 min, but not against treatment with 50 mM dithiothreitol. In addition, TGF-beta was also partially purified from the same extract. The purified TGF-beta did not show any inhibitory activity toward the growth of BRL, MDCK, BSC-1, or NRK.

Blood Platelets↗
PubMed1984

Proteoglycan distribution in rat aortic wall following indwelling catheter injury.

The morphologic response of the aortic wall of the normal fed rat to intimal injury by an indwelling catheter in place for 3 weeks was examined at the time of removal of the catheter and 4, 8, and 26 weeks later. Changes in the concentration of glycosaminoglycan were assayed morphometrically in ruthenium red-stained sections examined by transmission electron microscopy. Two types of ruthenium red-positive granules were identified in the intercellular matrix; large (greater than 20 nm), containing chondroitin sulphate and small (less than 20 nm) containing heparan sulphate. Endothelial denudation and some thrombus seen at the time of removal of the catheter, was associated with a decrease in the concentrations of both types of granules in the subendothelial space compared to normal rats. At later time intervals there was neointimal thickening containing no lipid, and occasional small areas of lipid accumulation. Compared to normal rats there was no significant change in granule concentration in the subendothelial space at any time interval. There was a slight increase in the concentration of large granules of the deep neointima at the time of removal of the catheter and after 4 weeks. In lipid-containing areas there was a highly significant increase in large granule concentrations compared to normal or to intimal thickening without lipid. The observations support the possibility that lipid accumulation is related to an increase in glycosaminoglycan concentration.

Animals↗
PubMed1984

Proteoglycans in human atherosclerotic lesions--a pilot qualitative and quantitative study by ruthenium red.

A pilot study was carried out to test whether normal human aorta and aortic atherosclerotic lesions obtained at post-mortem examination were suitable for the demonstration of proteoglycans (PGs) by ruthenium red (RR) staining, and whether by this method qualitative and quantitative differences of PGs might be detectable in various types of lesions and between lesions and the normal aortic intima. The results indicate that the PGs of the above tissues obtained at post mortem were clearly visualized by electron microscopy using the RR-indicator and were thus suitable for quantitative and qualitative evaluation. Of the RR-positive granules only those 20 nm and larger were assessed. RR-granules measuring 20-50 nm were present in normal intima and media, in increased concentration in the innermost part of the mixed fatty-gelatinous lesion, and in a decreased concentration in the fibrous cap of an atherosclerotic plaque. The same RR-granules were observed in a fatty streak and in addition 50-100 nm granules were present in this type of lesion; the overall RR-granule-concentration was reduced here. Granules of both sizes were interconnected by filamentous network. The differential presence of the large (and hitherto unreported) as well as the smaller granules in the various lesions is briefly discussed in the light of the present-day knowledge of tissue-PGs, and the importance of an examination in situ of the compound PGs-complexes in their native form, is emphasized.

Aorta↗
PubMed1983

Peptide immunoreactive nerves and cells of the guinea pig gall bladder and biliary pathways.

Using the methods of immunocytochemistry and radioimmunoassay, five peptides (vasoactive intestinal polypeptide (VIP), substance P, somatostatin, met-enkephalin, and bombesin) have been found in the gall bladder and the biliary tracts of guinea pig and each of them possesses a characteristic distribution pattern. Networks of nerves containing each peptide were found in the smooth muscle, around blood vessels and, occasionally, in the lamina propria. The distribution of the peptide immunoreactive nerves in the gall bladder and biliary tract is similar to those found in the gut. Vasoactive intestinal polypeptide (11 +/- 1.5 pmol/g in the sphincters, mean +/- SEM) and substance P (21.5 +/- 1.8 pmol/g in the common bile duct) were found to be the most abundant peptides and a few VIP and substance P immunoreactive neurones were localised in the ganglionated plexus. Bombesin immunoreactive nerves were mainly seen in the sphincter of Oddi, where the mean concentration of extractable bombesin was 14.6 +/- 2 pmol/g. Somatostatin immunoreactive mucosal endocrine cells were identified in the epithelium of the common bile duct and the sphincter. The extractable somatostatin in these regions were 76 +/- 19 pmol/g and 162 +/- 30 pmol/g respectively.

Animals↗
PubMed1983

[Comparative double-blind study of cefotetan and cefmetazole in patients with purulent peritonitis].

A clinical study of daily administrations of CTT (2g) and CMZ (4g) was performed by randomized double blind techniques in order to compare the clinical efficacy, side effects and usefulness. The 150 cases studied were as follows; Purulent peritonitis due to perforated gastrointestinal tracts (122 cases), traumatic peritonitis (4 cases), biliary peritonitis (7 cases), postoperative peritonitis (7 cases), intraabdominal abscess (6 cases); 4 cases were excluded from the statistical evaluation because of protocol deviation. 1. No significant differences in background parameters were found between the 2 groups. 2. Clinical evaluation of the efficacy rate by the attending physician revealed no significant differences between the 2 groups (CTT 82%, CMZ 74%). However, in severely perforated duodenal and/or gastric ulcer cases, greater clinical effectiveness was obtained in the CTT group than in the CMZ group (P less than 0.05). 3. Clinical evaluation of the efficacy rate by the committee revealed no significant differences between the 2 groups; 86% and 82% for the CTT and CMZ groups, respectively. However, in cases which showed marked effectiveness, although statistical significant differences were not found between the 2 groups (P less than 0.1), the CTT group (53%) was superior to the CMZ group (38%). In 122 cases of the purulent peritonitis, the efficacy rate was 92% in the CTT group and 86% in the CMZ group; this difference was also statistically significant by U-test (P less than 0.05). 4. The effectiveness was also evaluated by microbiological study in 90 cases. No significant differences were found in the ratio of eradication of isolated bacteria between the 2 groups; 30 of 44 cases (68%) in the CTT group and 34 of 46 cases (74%) in the CMZ group. 5. With regards to this eradication of bacterial strains; 115 of 119 strains (96.6%) were eradicated in the CTT group and 115 of 126 strains (91.3%) in the CMZ group. 6. Side-effects were noted in 2 cases in the CTT group; one case of nausea with chest discomfort and the other case of drug eruption. In the CMZ group, only 1 case of drug eruption was noted. Moreover, no significant differences were found in the laboratory findings between the 2 groups. Based on these results it was concluded that the clinical effectiveness of CTT (1 g twice daily) against peritonitis is as excellent as that of CMZ (2 g twice daily), both drugs being administered by drip infusion.

Adolescent↗
PubMed1979

Re-evaluation of the relationship between the positive inotropic effect of ouabain and its inhibitory effect on (Na+ + K+)-dependent adenosine triphosphatase in rabbit and dog hearts.

Previous studies have shown that in the ouabain-exposed rabbit heart, although positive inotropy and inhibition of (Na+ + K+)-dependent adenosine triphosphatase are induced concomitantly, the extent of inhibition of the enzyme remains constant when positive inotropy is washed out; and in the dog heart, if positive inotropy without arrhythmias is induced by ouabain, inhibition of the enzyme is not detected. The purpose of this work was the re-evaluation of these previous findings. Rapid recovery of the enzyme from small tissue samples was achieved by homogenization in 1 M KCl and centrifugation. When the enzyme was prepared by this method from ouabain-exposed rabbit and dog hearts, ouabain remained bound to the enzyme. The extent of inhibition of the enzyme was measured by the fluorimetric assay of K+-dependent 3-O-methylfluorescein phosphatase before and after removal of bound ouabain. Correlation between the extent of inhibition of this activity and that of (Na+ + K+)-dependent adenosine triphosphatase activity was established. Utilizing these refined methods, the following results were obtained. In the rabbit heart, positive inotropy and enzyme inhibition occurred concomitantly. Washout of the effect resulted in partial reactivation of the enzyme. In the dog heart, the previous findings were confirmed. The results are not inconsistent with the hypothesis that enzyme inhibition is the cause of the positive inotropic effects. They do suggest, however, the need for further testing of the hypothesis.

Animals↗
PubMed1977

Theoretical calculation of the dielectric constant of a bilayer membrane.

The dielectric constant (epsilon) and refractive index (n) of a bilayer lipid membrane is determined from the known values of the polarizabilities of the carbon-carbon and carbon-hydrogen bonds. It is assumed that the hydrocarbon chains are hexagonally arranged in an all-trans conformation perpendicular to the plane of the membrane. The only variable in the calculation is the average separation between the chains and the theory relates epsilon to this separation. The calculation and results differ significantly from those presented in a 1968 publication by Ohki. It is shown that a thin membrane is not homogeneously polarized by the applied field. This effect is analysed and the dependence of epsilon on the membrane thickness is determined. The theoretical results are in good quantitative agreement with experimental measurements on bulk paraffins and on oriented multilayers of saturated fatty acids. The most important conclusion is that the dielectric constant for an applied field perpendicular to the membrane (which is the appropriate value for capacitance measurements) differs by only a few percent from the value for the macroscopic (bulk) liquid hydrocarbon. Thus the dielectric constant of a bilayer membrane can be approximated by the value for the appropriate bulk hydrocarbon.

Electric Conductivity↗
PubMed1977

Chemical and histochemical studies of human alveolar collagen fibers.

Light and electron microscopic studies have established that the normal human alveolar argyrophilic (reticulum) fiber is collagen fiber. The silver impregnation method is highly sensitive and specific for histologic demonstration of the elaborate collagen fiber network of alveolar septa. The argyrophilic alveolar collagen fiber does not stain with the periodic acid-Schiff (PAS) or periodic acid-thiocarbohydrazide-osmium tetroxide (PTO) reaction. The materials positive for the PAS and PTO reactions in alveolar septa are epithelial and endothelial basal laminas, which are nonargyrophilic. Chemically, lung collagen fibers are composed of Type I and Type III collagens, which differ in amino acid composition, chain composition, and carbohydrate content. The chemical heterogeneity of lung collagen may have important biologic implications in the maintenance of normal structure and in the repair of lung injury.

Adult↗