Biomedical subjects

S W Tan

Publications and source records attributed to S W Tan.

23 records · Page 2Linked to original sources

PubMed1996

Production and characterization of murine monoclonal antibodies to Blastocystis hominis.

Several hybridomas producing antibodies detected by enzyme-linked immunosorbent assay (ELISA) were established by fusions of mouse myeloma P3.X63.Ag8.U1 with spleen cells from BALB/c mice immunized against an isolate of Blastocystis hominis. Five strongly positive hybrids (6B6, 1D5, 1E7, 4F7 and 4G11) were cloned and all were found to secrete IgM monoclonal antibodies. Four MAbs (6B6, 1E7, 4F7 and 4G11) reacted in immunoblots with a number of B. hominis antigens (mol. wt ranging from 25,000 to 220,000) which were likely to be repeating oligosaccharide epitopes located on glycoproteins, as indicated by pronase and periodate treatment. Another MAb (1D5) reacted with a single antigenic band (mol. wt 30,5000). Similar results were obtained in immunoblots using 4 other B. hominis isolates. Indirect fluorescent-antibody assay (IFA) using MAbs showed 3 patterns of reactivity. 1D5 showed patchy fluorescence, 4F7 showed peripheral fluorescence and 6B6, 1E7 and 4G11 showed bright diffuse fluorescence. These patterns were observed for all 5 human Blastocystis isolates. The MAbs exhibited some cross-reactivity with 2 reptilian Blastocystis isolates but not with Giardia intestinalis, Trichomonas vaginalis or Entamoeba histolytica.

Animals↗

PubMed1994

The micro-determination of serum gamma-glutamyl transferase.

The method of serum gamma-glutamyl transferase colorimeter assay was modified by changing the wave length from 420 nm to 400 nm, the incubated temperature from 37 degrees C to 50 degrees C, the sample amount from 30 microliters to 6 microliters. The modified method was proved to be more sensitive, with CV of intra-group being 2.06% and accuracy 97.4%. The method is suitable for clinical application with small-amount blood samples collected from earlobe or finger tip.

Adult↗

PubMed1993

Ganglioneuroma of the duodenum. Report of a case and literature review.

A 43-year-old male presented with upper gastro-intestinal bleeding. A polypoid tumor mass in the second part of the duodenum was found by endoscopic examination. Pathology revealed an extremely rare case of ganglioneuroma. The surgical local resection of the tumor was a sufficient procedure because of a lack of malignant potential. This is the fourth case since the first case was reported by Dahl et al in 1957 (1). We review the literature concerning duodenal paragangliomas, and discuss the histogenesis.

Adult↗

PubMed1993

Hepatolithiasis, a clinical study.

Ninety-seven hepatolithiasis cases were reviewed retrospectively. Primary hepatolithiasis was about equal in both sexes, with most patients under 39 years of age. Most secondary hepatolithiasis patients who were female-predominant, were older than 40. Common presenting symptoms were abdominal pain, either epigastric or right upper quadrant of abdomen as noted in 93%; chills and fever in 70%; nausea and vomiting in 49.5%; jaundice was noted only in 39% of the patients. Blood tests showed elevation of alkaline phosphatase in 79.8%, and gamma-GT in 88.3%. Left branch involvement was much more common that right. Escherichia coli (E. coli) was the main organism isolated in most of the cases. Abdominal ultrasonography reached a diagnostic rate of 91.01%, and the condition could be missed in cases of intrahepatic muddy stones, pneumobilia and misidentification of the location of the stones. Endoscopic retrograde cholangiography (ERC) showed a clearer picture of the biliary tree, but failed in cases of distorted anatomy because of previous operation, stones impacted in the ampulla orifice, presence of diverticulum or poor opacification of the bile duct because of stricture or stone impaction.

Adolescent↗

PubMed1990

Hyaluronic acid--a versatile biopolymer.

Since its discovery from bovine synovial fluid, hyaluronic acid has found application in several diverse areas. It is now extensively used in ophthalmic surgery, in the treatment of lameness in racehorses and as an ingredient in cosmetics. It can also be used in drug delivery, orthopedics, cardiovascular aids and in wound healing. Even so, its potential as a therapeutic agent is yet to be fulfilled. New improved products, formed by crosslinking hyaluronic acid with itself or other chemicals, are being produced. Hyaluronic acid is clearly a most valuable therapeutic biopolymer. This article reviews the properties of hyaluronic acid, its biosynthetic pathway and its methods of commercial production, and provides an estimation of its current and future world demand. Experiments designed to improve production economics have been performed in our laboratory. These involved control of glucose and yeast extract concentrations and fermentation pH. Hyaluronic acid production by Streptococcus zooepidemicus was found to be lower at pH 6.5 than at pH 7.1. A new method of extending the production of hyaluronic acid by S. zooepidemicus into the stationary phase has also been achieved.

Biopolymers↗