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T H Chang

Publications and source records attributed to T H Chang.

At least 109 records · Page 6Linked to original sources
PubMed1976

The isolation and characterization of bilirubin diglucuronide, the major bilirubin conjugate in dog and human bile.

The chemical structure of the major conjugate of bilirubin was unequivocally elucidated by structural analysis. The conjugated bilirubins were first separated from the lipid components of human duodenal aspirates or dog gall-bladder bile, and then resolved by t.l.c. into a series of tetrapyrroles. The major tetrapyrrole was then converted into its more stable dipyrrolic azo derivative for further analysis. The conjugated moiety of the azopigment was characterized after methanolysis with sodium methoxide. This reaction yields two types of product, those soluble in water and those soluble in organic solvents. The organic-soluble fraction was shown by t.l.c. and mass spectrometry to contain the methyl esters of the dipyrrolic azo derivatives of bilirubin. The water-soluble materials were analysed by enzymic procedures, t.l.c., n.m.r. spectrometry and combined g.l.c. and mass spectrometry. This analysis showed that the only water-soluble product resulting from the methanolysis was glucuronic acid. The structure was identical with that of pure standards, on both mass spectrometry and n.m.r. spectroscopy. No contaminating moieties were found. Quantitative measurement indicated that the glucuronic acid had been released in a 1:1 molar ratio with the resulting methyl esters of the dipyrrolic azo derivatives of bilirubin. This unequivocally establishes bilirubin diglucuronide as the major pigment present in bile. Past problems with identification of bilirubin diglucuronide were shown to originate from procedures which resulted in incomplete separation and isolation of the azopigments of the conjugated bilirubins, owing to contamination by biliary lipids.

Animals↗
PubMed1975

Proximal jejunal reversal procedure without interposition for management of dumping syndrome.

For control of disabling dumping syndrome, a short jejunal reversal interposition between the gastric remnant and the duodenum or between the gastric remnant and the jejunum with or without a second jejunal reversal is in current use. A new procedure, proximal jejunal reversal based on a modified antiperistaltic Roux-en-Y without interposition of the jejunal loop is presented and three cases are reported.

Adult↗
PubMedDate not supplied

Staphylococcus aureus peptidoglycan ameliorates cyclophosphamide-induced impairment of wound healing.

Cyclophosphamide given systemically to rats leads to impaired wound healing, characterized by decreases in the inflammatory reaction, fibroplasia, neovascularization, reparative collagen accumulation, and wound breaking strength. In contrast, the local application of Staphylococcus aureus peptidoglycan at the time of wounding increases all of these processes in normal rats. Accordingly, we hypothesized that inoculation of S. aureus peptidoglycan into wounds of cyclophosphamide-treated rats would ameliorate the otherwise impaired healing. Dorsal bilateral skin incisions and subcutaneous implantation of polyvinyl alcohol sponges (two on each side) were performed on male Sprague-Dawley rats receiving either saline or cyclophosphamide (24 mg/kg) intraperitoneally at the time of operation, on postoperative days 1, 2, 3, 4 (for rats killed on postoperative day 7), and also on day 8 (for rats killed on postoperative day 14). The incisions on one side were inoculated at the time of closure with 0.2 ml of saline solution, and the incisions on the other side with 6 mg S. aureus peptidoglycan in 0.2 ml saline solution (860 microg/cm incision). The sponges were instilled with 0.1 ml saline solution on the saline solution-instilled incision side or with S. aureus peptidoglycan 0.5 mg/sponge) in 0.1 ml saline solution on the other side. In control rats receiving saline solution intraperitoneally, incisions treated with S. aureus peptidoglycan were significantly stronger than saline solution-treated incisions by a factor of 1.8 at 1 week (p < 0.001); at 2 weeks the increase was small and not significant. Cardiac blood leukocytes and platelets fell markedly (90%) in cyclophosphamide- treated rats, and there was a decrease in wound breaking strength of their saline-treated incisions at both 7 and 14 days compared with saline solution-treated incisions of control rats. S. aureus peptidoglycan treatment of the wounds completely prevented this effect at 7 days, and partially at 14 days. Polyvinyl alcohol sponge reparative tissue hydroxyproline, 7 days after surgery, was decreased in cyclophosphamide-treated rats; this was completely prevented by S. aureus peptidoglycan treatment of the sponges. Histologically, the inflammatory response to the wounding, influx of macrophages and fibroblasts, angiogenesis, and collagen accumulation were all reduced at day 7 and 14 after surgery in the sponge reparative tissue of cyclophosphamide- treated rats; this was prevented by S. aureus peptidoglycan treatment of the sponges. In conclusion, a single local application of S. aureus peptidoglycan ameliorates cyclophosphamide-impaired wound healing.

Journal Article↗