Biomedical subjects

H Y Lim

Publications and source records attributed to H Y Lim.

29 records · Page 2Linked to original sources

PubMed1992

The value of immunohistochemical detection of P-glycoprotein in breast cancer before and after induction chemotherapy.

We have studied the patterns of P-glycoprotein expression before and after 3 cycles of induction chemotherapy (5-fluorouracil, adriamycin and cyclophosphamide) using immunohistochemically stained paraffin-embedded specimen of 28 patients with locally advanced breast cancer. The frequency of P-glycoprotein expression in untreated breast cancer turned out to be very low: only one out of 28 untreated, biopsy specimen at the time of diagnosis was positive. The frequency of P-glycoprotein expression was markedly increased from 9.1% before chemotherapy to 63.6% after induction chemotherapy (p = 0.006). After 3 cycles of induction chemotherapy, 25 patients had obtained clinical response to chemotherapy (4, CR; 21, PR). Eleven out of 25 tumors (44%) showing clinical response and all three tumors (100%) with minimal response have expressed P-glycoprotein. One out of 6 patients (16.7%) with microscopic residual tumor seen in mastectomy specimen expressed P-glycoprotein, whereas 13 of 22 patients (59.1%) with gross residual tumor showed the presence of P-glycoprotein (p = 0.08). The frequency of intrinsic P-glycoprotein expression in untreated breast cancer was quite low, but approximately half of the patients do acquire P-glycoprotein expression during the cycles of induction chemotherapy. Therefore, the results suggest that the immunohistochemical detection of P-glycoprotein on residual tumor cells after induction chemotherapy can predict acquired drug resistance in breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Should all the N3 lymph nodes group metastasis be regarded as distant metastasis (M1) in curatively resected gastric cancer?

Recently, metastasis to N3 lymph nodes group was regarded as distant metastasis by the new TNM staging system due to poor overall survival. However, the 5-year overall survival rate of patients with metastasis to N3 groups was 34.5% after curative surgery. Moreover, in patients with metastasis to lymph node subgroups of #12, #13, #14, the overall 5-year survival rate increased upto 47.2% after curative resection and adjuvant chemotherapy. This was similar to that of the patients with metastasis to N1 and N2 lymph nodes groups. But in these highly tumor burden states, no survival benefit was found with the addition of immunotherapy to chemotherapy as we achieved in stage II and III. Therefore, we suggest that, at least, metastasis to #12, #13, #14 lymph nodes subgroups should not be categorized as a distant metastasis. And in these situations, active curative radical surgery with extended lymphadenectomy and adjuvant chemotherapy are recommended.

Adult↗

PubMed1992

Community acquired urinary tract infections in Singapore: a microbiological study.

We studied 214 patients with culture proven community acquired infections. A total of 219 organisms were isolated, of which 68.2% were Escherichia coli, 10.1% Klebsiella sp and 5.5% Proteus mirabilis. Gram positive cocci accounted for 10.5% of organisms isolated. The majority of organisms isolated were sensitive to nalidixic acid (81.1%), nitrofurantoin (80.7%), cephalexin (74.7%) and trimethoprim-sulphamethoxazole (65.0%). Resistance to ampicillin was common (49.8%), as such the use of ampicillin in community acquired urinary tract infections will result in a high failure rate.

Adolescent↗

PubMed1991

Coexisting mycosis fungoides and Hodgkin's disease as a composite lymphoma: a case report.

Within the past few years, an increasing number of reports of Hodgkin's disease following the diagnosis of, and frequently coexisting with, mycosis fungoides have appeared. Previously, Hodgkin's disease found in the lymph nodes of the patient diagnosed as mycosis fungoides was considered as a transformed form of the mycosis fungoides. But, now it has been proven that Hodgkin's disease and mycosis fungoides are histologically and immunohistochemically distinct disease entities. We report a well-documented case of a man who developed Hodgkin's disease and mycosis fungoides simultaneously as a composite lymphoma. Our case emphasizes the importance of considering the diagnosis of another lymphoma in patients with mycosis fungoides who have lymphadenopathy. The cutaneous mycosis fungoides and the Hodgkin's disease should be treated as an independent disease.

Adult↗

PubMed1988

The cardiac effects of arginine vasotocin in amphibians.

1. The cardiac effects of arginine vasotocin (AVT) on isolated atria were examined in three anuran and one urodele species. 2. AVT produced dose-related positive chronotropic and inotropic responses. 3. The responsiveness of the atrial tissue varied among species. 4. Both the basal atrial rate (AR) and tension (T) were attenuated in the presence of phentolamine and propranolol, alpha- and beta-adrenergic antagonists. Isoproterenol, a beta-adrenergic agonist, increased both AR and T, an effect which would be inhibited by propranolol. 5. The effects of AVT on both AR and T were not inhibited by alpha- and beta-adrenergic blockers, nor by verapamil and imidazole with the dosages used in the present study. 6. On the contrary, the effects of AVT on AR, but not T, was enhanced in the presence of both alpha- and beta-adrenergic blockers. 7. The mechanism of action of AVT on the amphibian atrium remains unknown.

Animals↗

PubMed1987

Nitrate consumption and the incidence of gastric cancer in Singapore.

The nitrate content of a wide variety of vegetables, fruits and meat purchased in Singapore were determined by high-pressure liquid chromatography. From the 1982 statistical figures of retained imports and local production of these items the average per capita daily consumption of nitrates was calculated and found to be 215 mg, one of the highest reported figures in the world. Two vegetables are not so popular with the Malays and Indians who comprise 21% of the population. If their consumption of these vegetables is ignored then the per capita daily nitrate consumption of the Chinese population amounts to 250 mg and those of the Malays and Indians to 113 mg. Although these may be overestimates they do appear to show an association with the male gastric cancer incidence rates (age-adjusted) of 44.8 for the Chinese, 10.3 for Malays and 19.4 for the Indians. This could, however, be a chance association.

Chromatography, High Pressure Liquid↗

PubMed1981

Differentiation and comparison of raw, prepared and dross opium.

Comparative studies involving colour tests, thin-layer chromatography (TLC) and gas-liquid chromatography (GLC) were made on raw, prepared and dross opium with a view to establishing means for their differentiation. Analysis of a large number of samples found in south-east Asia showed the typical patterns and results to be quite distinctive in the qualitative and quantitative aspects. The relative proportions of the major alkaloids in the two chromatographic systems were used to advantage in the comparison. Prepared opium was found to have a characteristic yellow fluorescent spot on the TLC plate when viewed under long-wavelength ultraviolet light. No positive marker was found for dross opium, its unusual features being the relatively high morphine and codeine content and the absence of narcotine, meconic acid and especially thebaine. Most of the prepared opium samples were found to have been made from a mixture of raw and dross opium. The modified hallucinogen reagent of Maunder was found to be a suitable alternative chromogenic spray in the TLC analysis.

Asia, Southeastern↗

PubMed1978

Heroin abuse and a gas chromatographic method for determining illicit heroin samples in Singapore.

The abuse of heroin (diacetylmorphine) in Singapore escalated sharply in 1975 and 1976, as indicated by the 35-fold increase in the number of heroin seizures and the 20-fold increase in the urine samples containing morphine since 1974. A rapid and simple GC method has been described to estimate diacetylmorphine (and caffeine). Monoacetylmorphine and acetylcodeine may be ascertained by an additional step involving acetylation. All gas chromatograms of a large number of samples analyzed consistently had the same pattern, indicating that they possibly had a common origin. This GC "fingerprint," together with the quantitative data, appears to be characteristic of the illicit Asian or Chinese type of heroin found in Singapore. The proportions of the four major ingredients in some twelve typical samples have been tabulated. Statistical data confirming the accuracy and reproducibility of the analytical method have also been presented.

Calibration↗

PubMedDate not supplied

Vascular endothelial growth factor in the serum of patients with non-small cell lung cancer: correlation with platelet and leukocyte counts.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent angiogenic peptide expressed in a wide variety of tumors, and it stimulates angiogenesis and increases vascular permeability. Increased expression of VEGF may be associated with advanced stage and poor prognosis in patients with non-small cell lung cancer (NSCLC). METHODS: Using enzyme-linked immunosorbent assay, the levels of VEGF were determined in serum from 41 patients with untreated NSCLC (Stage: IIB, 3; IIIA, 6; IIIB, 17; IV, 15; HISTOLOGY: squamous cell carcinoma, 18; adenocarcinoma. 14; undetermined, 9). RESULTS: The median VEGF level was 312 pg/ml, ranging from 70 to 1440 pg/ml. Patients were divided into high VEGF (>312 pg/ml) and low VEGF (< or =312 pg/ml) groups using the median value as a cut-off. There were no significant associations between the serum VEGF levels and various clinicopathologic characteristics including age, gender, histologic type, stage and treatment. A significant positive correlation was found between serum VEGF levels and platelet counts (r=0.495; P=0.001). In addition, serum VEGF levels also correlated with leukocyte counts (r=0.478; P=0.002). In seven patients with measurement of follow-up serum VEGF levels at the end of treatment (chemotherapy and/or radiotherapy), the median serum VEGF level significantly decreased after the treatment (416 pg/ml; range, 96-812 pg/ml vs. 185 pg/ml; range, 49-487 pg/ml; P=0.028). However, the median platelet count (317,000/microl; range, 190,000-395,000/microl vs. 246,000/microl; range, 72,000-271,000/microl; P=0.028) and leukocyte count (10,000/microl; range, 8700-17,200/microl vs. 5100/microl; range, 3900-9500/microl; P=0.018) also decreased after the treatment. There was no statistically significant difference in the median survival of the patients between high VEGF group and low VEGF group (8 months vs. 9 months, P=0.647). CONCLUSIONS: Although serum VEGF level was significantly associated with platelet and leukocyte counts in NSCLC patients, it did not correlate with tumor burden and prognosis of the patients.

Adenocarcinoma↗

PubMedDate not supplied

Ramosetron for the prevention of cisplatin-induced acute emesis: a prospective randomized comparison with granisetron.

Control of nausea and vomiting is very important in determining patient compliance with cisplatin chemotherapy. A multicentre, randomized, single-blind study was conducted to compare the tolerability and efficacy of ramosetron with those of granisetron over 24 h following cisplatin administration to cancer patients. In eight study centres, a total of 194 adult patients were randomly assigned to receive either intravenous ramosetron 0.3 mg or intravenous granisetron 3.0 mg. The anti-emetic effect of ramosetron determined from the no-vomiting rate lasted longer, but there was no significant difference in the number of acute vomiting episodes or the severity of nausea between the two groups. In the tolerability evaluation, there were no statistically significant differences between the two groups, except for a higher incidence of dull headache in the granisetron group. Ramosetron and granisetron appear to have equivalent efficacy and tolerability profiles, but the effects of ramosetron on the prevention of acute vomiting in patients undergoing cisplatin chemotherapy were longer lasting.

Adult↗

PubMedDate not supplied

Alpha-fetoprotein-producing gastric cancer.

We measured the sero-positivity rate of serum alpha-fetoprotein (alphaFP) of gastric cancer patients by ELISA assay; forty-two curatively resected patients, 14 palliatively resected patients, 8 who received explo-laparotomy or bypass surgery and 18 patients with systemic metastasis. The sero-positive rate was 9.8% (8/82) and the positivity increased with cancer progression. Sex, age and pathological type were similar between alphaFP-positive and -negative patients. The overall synchronous hepatic metastasis rates in alphaFP-positive and alphaFP-negative groups were 37.5% (3/8) and 12.2% (9/74), respectively (p=0.08). The predictability of synchronous liver metastasis in eight alphaFP-positive patients were as follows: 37. 5% of total patients (3/8), 50.0% (3/6) of unresectable patients, and 60.0% (3/5) of patients with systemic metastasis. In three alphaFP-positive patient with liver metastasis, all the hepatic lesions were intrahepatic and multiple, while in alphaFP-negative patients, 67% (6/9) of the hepatic lesions was single intrahepatic lesion or surface nodule. The predictability of both synchronous and metachronous liver metastasis in alphaFP-positive gastric cancer patients was 75%. These findings suggested that, in advanced stomach cancer patients, especially in stage IV, alphaFP can be used in predicting liver metastasis during follow-up.

Adult↗