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Biomedical subjects

W C Foong

Publications and source records attributed to W C Foong.

At least 19 recordsLinked to original sources
PubMed1991

Hamster cheek-pouch testing of dental soft polymers.

The hamster cheek pouch provides a suitable model system for the mucous-membrane irritation testing of dental materials. Poor retention of materials or difficulties in histopathological interpretation caused by surgical artifacts have been reported in published techniques. We describe a new "pouch-in-pouch" technique for mucous membrane irritation tests. The retention rate of polymer discs was 97% and 87% at 14 and 35 days, respectively. Clear differentiation was obtained between the tissue reaction to the test materials and the surgical procedure. Polymer discs containing dibutyltin diacetate (DBTD) or dibutyl phthalate (DBP) as plasticizer resulted in epithelial changes, including epithelial atypia, early papillomas, and areas resembling dysplasia. The potentially pre-malignant nature of these changes requires further investigation.

Animals↗
PubMed1990

Adenomyomatosis of the gall bladder: the NUH experience.

Adenomyomatosis (AD) is a degenerative disorder of the gall bladder wall which can be complicated by chronic inflammation and calculi. The true incidence of this disorder in South East Asians is not known. Nine Chinese patients with AD were discovered amongst 200 consecutive right upper quadrant ultrasound examinations. Four of them had cholecystectomy and were diagnosed as cholecystitis by the pathologist. Adenomyomatosis can be suspected on ultrasonography, but should be confirmed by oral cholecystography (OCG). There is great disparity in the ultrasound, OCG, surgical and histopathological diagnosis of this condition. This may be due to the fact that only complicated cases of AD come to surgery, where the presence of chronic cholecystitis or calculi detracts from recognising or overshadows the presence of AD. It is not known whether uncomplicated AD has any clinical significance and whether it, if given sufficient time, will lead to inflammation of the gall bladder.

Adult↗
PubMed1989

Effect of liposomes on hamster oral mucosa.

The histologic reaction to topically applied or intramucosally injected DPPC/chol (2:1 molar ratio) liposomes was investigated. No reaction to liposomes was observed 4 days after daily topical application. However, a mild focal immune type inflammatory reaction was observed after 21 days topical treatment. Intramucosal injection of liposome produced no irritation but a macrophage reaction limited to the injection site, which was followed by healing and complete tissue regeneration.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1988

Association of liposome-entrapped [3H]methotrexate with thioglycollate-elicited macrophages in-vitro.

The association of free or liposome-entrapped [3H]methotrexate [( 3H]MTX) with thioglycollate-elicited macrophages was investigated in-vitro. [14C]Cholesteryl oleate was incorporated into the liposomes as a lipid marker. [3H]MTX association with the macrophages was 5 to 9-fold higher with liposome-entrapped [3H]MTX than with the free drug. Macrophage-liposome association was biphasic, temperature-dependent and saturable at high liposomal lipid concentration. A high liposome cholesterol (CH) content or the presence of 2,4-dinitrophenol or colchicine also reduced macrophage-liposome association.

2,4-Dinitrophenol↗
PubMed1988

Retention and distribution of liposome-entrapped [3H]methotrexate injected into normal or arthritic rabbit joints.

Normal or arthritic rabbits were injected intra-articularly (i.a.) with free [3H]methotrexate ([3H]MTX) or liposomes containing [3H]MTX with [14C]cholesteryl oleate as a lipid marker. The distribution of 3H and 14C in the injected joint and other tissues was determined. Free [3H]MTX was rapidly cleared from the joint, 79% being excreted in the urine within 24 h of injection. Liposome-entrapment retarded [3H]MTX clearance from the joint (P less than 0.001), 45.5% being recovered from the joint 24 h after injection. Uptake of liposomes by the inflamed synovium was lower than expected, 4% liposomal [3H]MTX injected being associated with the synovium after 24 h. Nevertheless, this was 40-fold greater than when free [3H]MTX was injected. Liposome entrapment should improve the efficacy and reduce the side effects of drugs injected directly into the joint cavity.

Animals↗
PubMed1987

Clinico-pathological prognostic factors of large bowel cancer in Singapore: a multivariate analysis.

Clinical and pathological data from 219 cases of large bowel cancer were analysed using the Cox regression model to evaluate their effects on survival. Clinical variables such as sex, change in bowel habit, bleeding per rectum, tumour site, size and duration of symptoms had no significant influence on survival. Individually, age, abdominal distension, Dukes' stage and tumour grade had significant influence on survival. When considered together, Dukes' stage was the only variable selected. Therefore Dukes' stage is the most important prognostic factor in colorectal cancer. The distribution of patients was 25, 18, 26 and 31 percent for Dukes' A, B, C and D respectively. The probabilities of survival at five years were 71, 55, 36 and 16 percent for the respective Duke's stages. These data show that the clinical and pathological variables of patients with colorectal cancer in Singapore and the factors significantly associated with survival are similar to those in western countries.

Adult↗
PubMed1986

Acute cholangitis in Singapore.

115 cases of acute calculous cholangitis were analysed for their presentations, treatment and complications. There were slightly more Chinese males than females (1.4:1) and the mean age was 62 years old. Though pain was the commonest symptom (95.7%), only 35.7% of patients had complete Charcot's triad. 21.7% presented in septicaemic shock. E. Coli and Klebsiella were the commonest organisms isolated. All patients had cholecystectomy and exploration of common bile ducts. Twenty patients had additional choledochontrostomy performed. 50.4% of patients developed complications and the overall mortality was 16.5%. Patients over 60 presented in shock carried a significantly higher mortality (40%).

Acute Disease↗
PubMed1985

Primary hepatocellular carcinoma associated with Wilson's disease in a young woman.

A 27 year old woman with hepato-lenticular degeneration (Wilson's disease) was found to have primary hepatocellular carcinoma (PHC) three and a half years after she was started on treatment with D-penicillamine. The tumour was resected since when she has remained well. Her liver function tests were normal throughout the course of her disease. The available literature is reviewed and possible mechanisms for this association proposed.

Adult↗
PubMed1984

Stone composition and metabolic study in urinary calculous disease.

A series of 178 urinary stones is analysed qualitatively during a three year period from 1980 to 1982. The majority (96%) of stones orginate from the upper tract. Calcium oxalate stones are the commonest entity seen in the western countries but less than 20% of such stones occur locally. A large proportion consists of mixed stones and one third are infective as triple phosphate is present. 20% contain urate as a constituent whereas relatively pure urate stones constitute 4%. The true incidence of pure urate stones is higher (about 10%) as we have been dissolving them with alkalinisation of urine without surgery. Idiopathic hypercalciura occurs in 11.8% and none has persistent hypercalcaemia. Hyperuricosuria which is commoner, occurs in 24% of patients. It is important to identify this group as it results in the formation of metabolically active stones, and they can be treated with allopurinol to prevent recurrence of stones.

Adult↗
PubMed1980

Adriamycin in the treatment of resectible and irresectible primary hepatocellular carcinoma.

The treatment of 205 patients with primary hepatocellular carcinoma in Singapore from 1975 to 1980 is reviewed. Adriamycin given at a dose of 40 mg/m(2) intravenously every 4 weeks for irresectible tumours achieved a response rate of 32% alone and has significantly prolonged the median survival time to 4 1/2 months (135 days) in these individuals. Despite this response only 1/34 (3%) patient showed complete remission and is alive at 2 1/2 years. Use of other combinations with Adriamycin e.g. 5 Fluorouracil and Vincristine produced a significant response in the first 16 weeks (p < 0.005) but not thereafter, when completed with the historical group. To improve the response and to consolidate this response, split doses of total hepatic irradiation (to a maximum of 3,150 rads) and alternate day administration of intravenous Adriamycin 10 mg (to a maximum of 90 mg) were given. 12/23 patients (50%) responded. This was followed by a four weekly Adriamycin, 5 F.U. and Vincristine. Median survival time was 5 1/2 months (165 days). Relapse occurred in all patients. Similarly in 5 patients who had resections, early recurrences occurred in 3/5 (60%) within 3 months, inspite of postoperative chemotherapy with Adriamycin, 5 F.U., Vincristine and Cyclophosphamide given every four weeks. In view of the high recurrence rate following effective treatment, further studies on the biological behaviour of these abnormal livers is required.

Antineoplastic Agents↗
PubMed1978

Unusual small intestinal obstruction in adolescent girls: the abdominal cocoon.

Ten cases of small intestinal obstruction seen over a period of 6 years (1971-6) in young girls within the narrow age range of 13-18 years are described. The patients were all within 2 years of menarche. In all these cases the obstruction was due to a membrane encasing the small intestine in the manner of a cocoon. There was no previous history of abdominal operation, peritonitis or prolonged drug intake. The clinical features, operative findings and management of the cases are presented. Possible causes of the condition are discussed. In view of the similar clinical presentation in all these patients, their conditions can be grouped as a clinical entity--'the abdominal cocoon'.

Adolescent↗