Biomedical subjects

L C Wong

Publications and source records attributed to L C Wong.

At least 37 records · Page 2Linked to original sources

PubMed2001

Anti-apoptotic proteins, apoptotic and proliferative parameters and their prognostic significance in cervical carcinoma.

The inhibitor of apoptosis proteins (IAP) suppress apoptosis induced by a variety of stimuli. The aims of this study were to: (a) compare the expression of X-linked IAP (Xiap) and Human IAP-2 (Hiap-2) in cervical carcinoma cells and normal cervix, (b) determine the correlation between IAP expression and tumour apoptosis or proliferation, and (c) assess their prognostic significance in cervical carcinomas. Paraffin-embedded tissue sections were retrieved from 77 patients with cervical squamous carcinomas prior to treatments and 47 normal subjects. Tumour apoptosis was determined by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuracil triphosphate (dUTP) nick-end labelling (TUNEL) and apoptotic index (AI), and the proliferative rate was measured by Ki-67 and mitotic (MI) indices. Immunoreactive Xiap and Hiap-2 were found in both cervical cancer cells and normal tissues. IAP expressions in cancers did not correlate with apoptotic and proliferative parameters, disease stage and patient survival. The lower AI and Ki-67 index were associated with a better survival. In conclusion, the basal expression levels of IAPs have no prognostic significance, but AI and Ki-67 expression are potential prognostic indicators in cervical carcinoma.

Adult↗

PubMed2001

Severe cyclical thrombocytopenia in a patient with a large lymphatic-venous malformation: a potential association?

The case is reported of an infant who had a large vascular malformation involving his left arm and axilla. It was initially believed to be purely lymphatic in composition but some venous elements were identified subsequently, at operation. The lesion was unusual in that there was a total absence of skin over one area of it at birth, that it underwent spontaneous shrinkage in the early weeks of life, and that a circumferential scarring developed which led to severe functional disability of the limb. At 12 months of age the patient developed a profound cyclic thrombocytopenia that spontaneously resolved after 1 year. The cause of the platelet cycling is unresolved but might have been secondary to intermittent production by the malformation of a cytokine which was destructive against the platelets.

Arm↗

PubMed2001

Vergence adaptation in children and its clinical significance.

BACKGROUND AND PURPOSE: Vergence adaptation has not been well investigated in children even though it may contribute to binocular dysfunction and near work induced asthenopia. METHODS: We compared vergence adaptation in 18 children and 18 young adult subjects by assessing tonic vergence (TV) before and immediately after a period of sustained near fixation, by measuring heterophoria with a synoptophore through 0.5 mm binocular pinholes. Adaptation was induced by a reading task at 15 cm for a continuous 5 minute period. RESULTS: Mean pre-task TV values of 0.70 MA (Meter Angles) and 0.20 MA were observed for the children and young adults, respectively (p = 0.08). The initial mean vergence adaptation for children and adults was +0.45 MA and +0.11 MA, respectively (p = 0.001). CONCLUSION: The greater vergence adaptation observed in children may impact upon the clinical assessment of their binocular vision, especially heterophoria measurement which may require longer periods of dissociation than previously recommended, and might also ultimately be partly responsible for the predominant development of esodeviations during childhood

Adaptation, Ocular↗

PubMed2000

Propofol increases agonist efficacy at the GABA(A) receptor.

Using the whole-cell patch-clamp technique, we have determined that propofol, but not midazolam, increases the efficacy of piperidine-4-sulphonic acid (P4S), a partial agonist at alpha1beta1gamma2s, GABA(A) receptors expressed in HEK 293 cells. These findings are consistent with the idea that propofol facilitates receptor gating, while midazolam increases receptor occupancy by the agonist.

Allosteric Regulation↗

PubMed2000

Clinical applicability of the ATP cell viability assay as a predictor of chemoresponse in platinum-resistant epithelial ovarian cancer using nonsurgical tumor cell samples.

OBJECTIVES: There is no basis for choosing one chemotherapy over another in platinum-resistant epithelial ovarian cancer based on published response rates. This study explores the feasibility and accuracy of the ATP cell viability assay (ATP-CVA) in predicting chemoresponse in these difficult situations to choose the most appropriate drug for treatment. METHODS: Predominantly nonsurgical tumor samples for histological proof of recurrence were tested against a panel of drugs for salvage chemotherapy. Clinicians were blinded to the test results. Patient responses were evaluated after a minimum of three cycles of single-agent chemotherapy and correlated with test results. RESULTS: The evaluability rate was 85% (5 of 33 contaminated). The majority (24) were obtained by abdominal paracentesis and trucut biopsy. Of the 28 successful assays, 8 were excluded from analysis because four chose not to have chemotherapy and four withdrew after fewer than three cycles because of unacceptable side effects. The overall response rate to salvage chemotherapy was 15%. The sensitivity was 100% and specificity 82%. Resistance was correctly predicted in 100% and response correctly predicted in 50%. The outcomes of 17 of 20 patients were predicted correctly, giving an accuracy of 85%. CONCLUSIONS: It is feasible to test nonsurgical tumor specimens in recurrent cancer. The ATP-CVA correctly identified a group of patients with a 50% chance of response to salvage chemotherapy. This information may be useful in the decision-making process. A prospective, randomized study will be done to confirm these results.

Adenosine Triphosphate↗

PubMed2000

Female urethral adenocarcinoma arising from urethritis glandularis.

INTRODUCTION: Female urethral adenocarcinoma is extremely rare and more than one tissue of origin has been suggested other than the Skene's gland. Immunohistochemistry with cytokeratins (CK) 7 and 20 is used to define the origin of the tumor. CASE REPORT: A 72-year-old woman presented with a 2-cm polypoid tumor at the external urethral meatus and bleeding. Wide local excision and bilateral inguinal lymphadenectomy were performed. Postoperative convalescence was uneventful. It was a poorly differentiated mucinous adenocarcinoma without direct urothelial involvement. There were focal areas of intestinal metaplasia. The tumor cells were positive for CK 7 and 20 and negative for prostate-specific antigen. DISCUSSION: This case provides supportive evidence that mucinous urethral adenocarcinoma may arise from malignant transformation of urethritis glandularis.

Adenocarcinoma↗

PubMed2000

Methotrexate infusion in low-risk gestational trophoblastic disease.

OBJECTIVES: The current study attempts to evaluate the effectiveness of methotrexate infusion therapy in the management of low-risk gestational trophoblastic disease and to find out whether an increase in the dose intensity can effect a faster remission and a shorter treatment duration. STUDY DESIGN: This is a prospective study. Between June 1990 and August 1998, 59 patients with low-risk trophoblastic disease were treated with methotrexate at a dose of 100 mg/m(2) as an intravenous bolus over 30 minutes followed by a 12-hour infusion of methotrexate at a dose of 200 mg/m(2). Folinic acid was not given unless the serum methotrexate reached a toxic level 24 hours after infusion (toxic level, 10 micromol/L). Actinomycin D was added in patients with a partial response. The follow-up period of these patients ranged from 12 to 113 months, with a median of 58.5 months and a mean of 55.7 months. RESULTS: Fifty-four patients attained a complete biochemical remission. Twenty-eight patients went into biochemical remission after one methotrexate infusion. Five patients showed a partial biochemical response. A relapse developed in 2 of the 54 complete responders at 3 months and 18 months after the initial therapy. Both patients received combination therapy consisting of methotrexate, etoposide, and bleomycin. They went into biochemical remission and have remained disease-free at the time of analysis. All of the 59 patients were in biochemical remission at the time of analysis. No significant side effects were observed except that Stevens-Johnson syndrome developed in 1 patient. CONCLUSIONS: Methotrexate infusion therapy described in this study is effective in the treatment of low-risk gestational trophoblastic disease. The omission of consolidation therapy and folinic acid rescue decreases the cost and duration of treatment.

Adult↗

PubMed2000

Loss of imprinting of the IGF-II and H19 genes in epithelial ovarian cancer.

To establish a possible role of genomic imprinting in the carcinogenesis of epithelial ovarian cancer, we determined the imprinting status of both IGF-II and H19 genes in 43 ovarian cancers, 7 low malignant potential ovarian tumors, and their matched normal tissues. In ovarian cancer, loss of heterozygosity (LOH) of IGF-II, H19 RsaI, and H19 AluI was found in 4 of 24 (16.7%), 3 of 20 (15%), and 1 of 16 (6.3%) samples, respectively. All patients with tumor specimens exhibiting LOH are of advanced clinical stages. Loss of imprinting (LOI) was found in 5 of 20 (25%) for IGF-II and in 4 of 17 (23.5%) and 1 of 15 (6.7%) for the RsaI and AluI sites of H19 gene with no LOH. However, no LOH was found in low malignant potential tumors, and only one of them showed LOI in H19 AluI site. Overexpression of IGF-II was demonstrated in all five LOI samples with normal expression of H19. Three of the five tumor specimens exhibiting LOI were transcribed from P1 promoter, whereas the remaining two were from the P3 promoter. These results suggested that LOH of both IGF-II and H19 genes was associated with advanced ovarian cancer. LOI of IGF-II and H19 genes may be involved in the development of ovarian cancer. Transcription of IGF-II from the P1 promoter may account for the biallelic expression of the IGF-II gene.

Female↗

PubMed2000

Aggressive angiomyxoma in females: is radical resection the only option?

BACKGROUND: Aggressive angiomyxoma is a rare mesenchymal tumor, characterized by frequent local recurrences. Our aim is to assess the role of radical resection. METHODS: Retrospective case review. The records of five patients with aggressive angiomyxoma during the period from 1984 to 1998 were reviewed and analyzed. A MEDLINE search from 1983 to May 1999 was performed. The clinical presentation, surgical treatment, resection margin involvement and clinical outcomes were analyzed. RESULTS: Together with our five cases, 106 cases have been reported in the world literature. The female-to-male ratio was 6.6:1. The age distribution was wide, with the peak incidence at 31 to 35. The local recurrence rate was high. Seventy-one percent of recurrence occurred within the first 3 years. Patients with clear resection margins have similar chances of remaining disease-free compared with those having tumor-involved resection margins. There was no correlation between the size of the tumors and the chance of recurrence. CONCLUSIONS: Though we aim for complete resection, incomplete or partial resection is acceptable, especially when high operative morbidity is anticipated and preservation of fertility is an issue. Long-term follow-up and careful monitoring with imaging techniques are essential for timely identification of recurrence and prompt resection.

Adolescent↗

PubMed2000

P73 gene expression in ovarian cancer tissues and cell lines.

Thep73 gene, a homology of p53, is a new candidate of imprinting and tumor suppressor gene. To investigate the role of p73 in ovarian cancer, we studied the allelic expression in 56 cases of ovarian cancer using StyI polymorphism analysis. We also examined p73 expression by semi-quantitative reverse transcription-PCR as well as by Western blot analysis and DNA methylation study of the CpG island in exon 1 in ovarian cancer tissues and cell lines. Loss of heterozygosity was found in 8.3% (2 of 24) of the cases. Biallelic expression was demonstrated in 91.7% (22 of 24) of the tumor samples, in 70.8% (17 of 24) of the normal samples, and in 1 ovarian cancer cell line. Imbalanced expression and monoallelic expression were found in three and two pairs of matched samples, respectively. Overexpression of p73 was found in advanced ovarian cancer rather than in early-stage disease or in borderline ovarian tumor. No significant difference was found in the p53 expression. Three cell lines with absent p73 protein expression and one tumor sample with monoallelic expression were methylated in the CpG island. Demethylation in SKOV3 cell line using 5-azacytidine can reactivate the expression of this gene in both the mRNA and the protein level. Our results indicated that p73 was not imprinted in most of the ovarian cancer and normal tissues, but it could be involved in the advanced ovarian cancer through overexpression. DNA methylation may contribute to the lack of p73 expression.

Adenocarcinoma, Clear Cell↗

PubMed1999

The effect of amifostine on the in vitro cytotoxicity of chemotherapeutic agents in three epithelial ovarian carcinoma cell lines.

OBJECTIVES: Amifostine protects against a spectrum of toxicities induced by chemotherapy without affecting tumor cell kill. This is supported by clinical data and in vivo animal studies. However, there is a paucity of data on its effect on the tumor cytotoxicity of several chemotherapeutic agents used in recurrent epithelial ovarian cancer. This study compares in vitro cytotoxicity before and after addition of amifostine. METHODS: Three epithelial ovarian carcinoma cell lines (SKOV3, 420, 429) were exposed to cis-platinum, paclitaxel, doxorubicin, etoposide, 5-fluorouracil, bleomycin, 4-epidoxorubicin, 4-HC (activated cyclophosphamide), vincristine, actinomycin D, mitomycin C, and topotecan. Cells were pretreated with either 0 or 1.2 mM amifostine. Tumor cell kill after 6 days of incubation was measured using the ATP cell viability assay. Paired samples Student's t statistic was used to test the difference in mean ATP levels between drug-treated samples with and without pretreatment with amifostine. RESULTS: SKOV3 was sensitive to paclitaxel, actinomycin D, 4-epidoxorubicin, and vincristine. Cell line 420 was sensitive to paclitaxel, etoposide, and 5-fluorouracil. Cell line 429 was sensitive to paclitaxel and 5-fluorouracil. There was no significant difference in the mean ATP levels between drug-treated samples with and without pretreatment with amifostine for each of the sensitive drugs in all three cell lines. Similarly, there was no significant difference in the mean ATP levels in cis-platinum and 4-HC treated samples with and without pretreatment with amifostine. CONCLUSIONS: These results show that at the cellular level amifostine did not protect epithelial ovarian carcinoma cells against tumor cell kill.

Amifostine↗

PubMed1999

Pathology slide review in gynecologic oncology: routine or selective?

OBJECTIVE: The aims of this study were to assess the cost/benefit ratio for interinstitution pathology consultation (IPC) and to identify the types of specimens with little or no risk of diagnostic error in order to reduce the cost. METHODS: All gynecologic oncology referrals having IPC from 1993 to 1998 were reviewed. Each case was evaluated by comparing both the original and the consulted pathology reports. A discrepancy was major if it led to treatment alteration. A minor discrepancy was defined as differences without clinical consequences. Consultation error was determined by comparison with the final diagnosis and clinical data obtained from the records. The cost per review was adjusted to 1998 dollars for all cases over the 5-year study period. Statistical data were obtained by Fisher's exact test and Pearson's correlation test. RESULTS: Five hundred sixty-nine pathology specimens from 498 patients were analyzed in this study. The major discrepancy rate was 6.5% and the minor discrepancy rate was 12.5%. Cytological specimens accounted for no major discrepancy and 13 minor discrepancies compared to 37 major and 58 minor discrepancies in histological specimens. The difference was statistically significant (P = 0.003). Consultation errors occurred in 5 cases with no alteration of clinical care. By excluding cervical and vaginal smears and cervical biopsy specimens in cases with clinically gross tumors, the cost can be reduced by 25% with no detriment to the clinical management. CONCLUSIONS: The types of specimens that do not need consultative pathology review include (1) cervical biopsy specimens in those patients with gross tumors and (2) cervical and vaginal smears.

Biopsy↗

PubMed1999

Role of serial tumor markers in the surveillance for recurrence in endometrial cancer.

The aim of this study is to evaluate the usefulness of tumor markers in the follow-up of patients with endometrial cancer. The sera of 23 patients with elevated pretreatment CA125, CA15.3, and CA19.9 were collected at each follow-up visit and analyzed. Eleven patients had normal posttreatment levels and none of them developed recurrence. Twelve patients had one or more increased tumor markers, 7 (58.3%) of them developed recurrence. Among these seven patients, six had CA125 elevated by at least 10-fold and one had elevated CA19.9. The median lead time between elevation of tumor markers and clinical evidence of recurrence was 6 months. Hence posttreatment elevation of CA125 is a useful predictor for recurrence in patients with elevated pretreatment levels.

Biomarkers, Tumor↗

PubMed1999

Prevention of postoperative nausea and vomiting in gynaecological laparotomies: a comparison of tropisetron and ondansetron.

In a randomized, double-blind study, the antiemetic efficacy of a single bolus of tropisetron 5 mg (group T, 37 patients), ondansetron 4 mg (group O, 39 patients) or saline (group C, 45 patients) given at induction was compared in a homogeneous group of 121 patients undergoing gynaecological laparotomy and receiving postoperative patient-controlled intravenous morphine for 24 to 48 hours. Fewer group T and group O patients developed severe nausea compared to group C (P < 0.01, log rank test in Kaplan-Meier analysis). Group T patients also had lower nausea scores than group O at 8 to 16h (P < 0.05). The overall incidences of severe nausea in groups T, O, and C were 5.4%, 17.9%, and 44.4% respectively (P < 0.001, group T vs group C; P < 0.05 group O vs group C). In conclusion, the 5-hydroxytryptamine 3 receptor antagonists tropisetron and ondansetron were superior to placebo in preventing PONV.

Antiemetics↗

PubMed1999

Chemoradiation and adjuvant chemotherapy in cervical cancer.

PURPOSE: Radiotherapy is the standard treatment for locally advanced cervical cancer, but treatment results remain disappointing, particularly for women with bulky central disease. We investigated the role of concurrent chemoradiation and adjuvant chemotherapy in a randomized trial. PATIENTS AND METHODS: Two hundred twenty patients with bulky stage I, II, and III cervical cancer were randomized to receive either standard pelvic radiotherapy or chemoradiation (epirubicin 60 mg/m(2)) followed by adjuvant chemotherapy with epirubicin 90 mg/m(2) administered at 4-week intervals for five additional cycles. RESULTS: Fifty-nine patients have relapsed, with a median follow-up duration of 77 months. Patients who received epirubicin radiation therapy showed a significantly longer disease-free (P =.03) and cumulative survival (P =.04). Patients who received radiation alone had significantly more distant metastasis than those who received chemoradiation (P =.012). There was no difference in long-term local tumor control (P =.99). CONCLUSION: Survival benefit has been demonstrated in patients treated with chemoradiation followed by adjuvant chemotherapy with epirubicin as compared with patients treated with standard pelvic radiotherapy alone.

Adult↗

PubMed1999

Mitomycin chemotherapeutic pleurodesis to palliate malignant pleural effusions secondary to gynecological cancer.

BACKGROUND: To assess the efficacy of mitomycin pleurodesis in women with end stage malignant effusion. METHODS: Retrospective analysis. RESULTS: Of the 13 patients treated six had ovarian, six had endometrial and one had cervical adenocarcinoma. The median time of onset of effusion from diagnosis of primary disease was 12 months (range 1-75). Ten patients were evaluable for response. The median age of the patients was 59 years (range 42 to 74). Ten (77%) of them had repeated thoracocentesis prior to mitomycin pleurodesis. The median duration and volume of drainage was 4 days (range 2-11) and 3.1 liters (range 1.2-10.2) respectively. One of two patients developed a pneumothorax and required the insertion of an additional chest drain. Overall, seven patients (70%) responded - one completely (CR) and six partially (PR), while three did not respond. Four of five patients with ovarian cancer had a partial response, two of four patients with endometrial cancer (one CR and one PR) responded. The only patient with cervical cancer had a partial response. Nine patients (69%) had enough symptomatic improvement to be discharged home. The drug cost of bleomycin 60 units (US$191), another commonly used agent, was more than twice as expensive as mitomycin 30 mg (US$84). CONCLUSIONS: Mitomycin pleurodesis can palliate 70% of patients for at least 1 month. It offers cheap and effective palliation. There is a suggestion that patients' quality of life is improved.

Adult↗

PubMed1999

Wide local excision (WLE) for vaginal intraepithelial neoplasia (VAIN).

BACKGROUND: To assess the use of wide local excision in the treatment of VAIN. METHODS: A retrospective review on 40 WLE procedures for VAIN. RESULTS: The mean age was 60 years. Thirty-six (90%) patients had previous treatment for genital tract cancer or pre-cancer. The median duration and blood loss during operation was 45 minutes and 50 mls respectively. Fifteen complications affected 11 patients. Only one of five patients with 'vaginal cancer' was diagnosed prior to WLE. Of the 35 patients treated for VAIN 3, 12 (34%) developed abnormal cytology during follow up three had residual VAIN 3, five had recurrent VAIN 3 and four had invasive cancer diagnosed. The remaining 23 (66%) patients were disease free at a median follow up of 44 months. CONCLUSIONS: Ablative therapy for VAIN 3 is unsafe as occult invasive foci can be missed by biopsy. WLE is efficacious in treating high grade VAIN 3. Long term surveillance of the lower genital tract is needed to diagnose metachronous lesions.

Aged↗

PubMed1999

Early detection of persistent trophoblastic tumour by serum human chorionic gonadotrophin monitoring after molar pregnancy.

OBJECTIVE: To study the outcome of a multi-centred post-molar pregnancy serum human chorionic gonadotrophin (hCG) surveillance programme. METHODS: Patients recruited into the multi-centred post-molar serum hCG surveillance programme between 1988 and 1996 were studied. The clinical data were obtained from medical records and computer database. RESULTS: There were 616 patients in the study. Twenty-five (11%) of 224 patients with molar pregnancy and 28 (7%) of 392 patients with partial molar pregnancy were diagnosed to have persistent trophoblastic tumour (PTT) requiring chemotherapy. Of the 53 patients treated for PTT, 58.5% received intravenous methotrexate (MTX), 22.6% received both MTX and actinomycin D, and 19% received CHAMOC, a multiple chemotherapeutic regimen. Four patients receiving single drug had to change the regimen because of poor response, and all recovered and remained well. There were 3 cases of recurrence, one in each group of patients receiving single, dual or multiple agents. One patient died because of treatment complication. The rest were well with a mean follow-up of 42 months. CONCLUSIONS: Post-molar serum hCG surveillance is important to detecting persistent trophoblastic activity. Early treatment of PTT by the appropriate chemotherapy has a near hundred percent cure and prevents the progression of PTT into more advanced trophoblastic malignancy such as choriocarcinoma.

Adolescent↗