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Biomedical subjects

L C Wong

Publications and source records attributed to L C Wong.

At least 55 records · Page 3Linked to original sources
PubMed1999

Cervical smear screening: questionnaire study of histories and attitudes of patients with squamous cervical carcinoma.

OBJECTIVE: To determine why invasive cervical carcinoma still occurs despite the availability of cervical smear screening services. DESIGN: Questionnaire survey and retrospective study of patient records of women who attended a gynaecological oncology out-patients clinic from 13 February 1997 to 30 June 1997. SETTING: Public hospital, Hong Kong. PATIENTS: Ninety-nine women (median age, 53 years; range, 30-79 years) who gave a history of squamous cervical carcinoma. MAIN OUTCOME MEASURES: The date of the last cervical smear test prior to the development of cervical carcinoma; reasons for non-attendance; attitudes to screening; and the stage and histological diagnosis of disease. RESULTS: Only 19 (19.2%) of the 99 patients had received routine cervical smear testing during the previous 3 years prior to their disease; 76 (76.8%) had not been tested within the past 10 years. The major reasons for not having been tested included being unaware that cervical carcinoma is preventable by screening or can be asymptomatic, being too busy to go for screening, and not knowing where to go for screening. After receiving treatment, 17 (17.2%) of the 99 patients still thought screening was unnecessary and 20 (20.2%) had no idea how frequently smears should be taken. CONCLUSION: The greatest barrier to effective cervical screening is patient ignorance. Public education about cervical smear screening in Hong Kong is needed.

Journal Article↗
PubMed1998

Clinical outcome of micrometastasis in the lung in stage IA persistent gestational trophoblastic disease.

BACKGROUND: Computed tomography (CT) of the thorax can be used in the staging of persistent gestational trophoblastic disease (PGTD). However, the prognostic significance of micrometastasis in the lung detected by CT of the thorax has not been well documented. The aim of the study is to define the effect of micrometastasis on the clinical course of the disease. METHODS: Thirty-five patients who had nonmetastatic GTD underwent CT thorax examination before treatment in the Department of Obstetrics and Gynaecology, University of Hong Kong. All patients had workups which showed no evidence of metastasis and were diagnosed as FIGO stage IA. They all received methotrexate (MTX) infusion therapy. RESULTS: Three groups of patients were identified based on the thorax CT findings. Sixteen patients (45.7%) showed no evidence of micrometastasis on CT thorax. Two of them (12.5%) had poor response to MTX with unsatisfactory fall in serum hCG levels requiring change of chemotherapy to actinomycin D. Nine patients had suspicious micrometastasis and one (11.1%) of them needed change of MTX. Ten patients had micrometastasis and one (10%) of them needed change of MTX. There was only one recurrence and it was in the suspicious micrometastasis group (11.1%). There was no statistically significant difference in the rate of poor drug response or recurrence among the three groups of patients. CONCLUSIONS: Micrometastases in the lung do not affect the clinical outcome of patients with FIGO stage IA disease. CT thorax is not essential in the staging of GTD.

Adult↗
PubMed1998

p21WAF1/CIP1 expression in gestational trophoblastic disease: correlation with clinicopathological parameters, and Ki67 and p53 gene expression.

BACKGROUND: The p21WAF1/CIP1 gene mediates growth arrest by inhibiting G1 cyclin dependent kinases and has been considered as a downstream effector of the tumour suppressor gene p53. AIM: To analyse the role of p21WAF1/CIP1 in gestational trophoblastic disease. METHODS: The immunohistochemical expression of p21WAF1/CIP1 gene was measured in 33 placentas, 28 partial hydatidiform moles, 54 complete hydatidiform moles, and 13 choriocarcinomas in paraffin wax embedded tissue. The results were correlated with p53 (DO7) and Ki67 (MIB1) immunoreactivity as well as clinical progress. RESULTS: p21WAF1/CIP1 immunoreactivity was found predominantly in the nuclei of the syncytiotrophoblasts. p21WAF1/CIP1 protein expression correlated with gestational age in normal placentas (p = 0.0001) but not in hydatidiform moles (p = 0.89). Complete hydatidiform moles and choriocarcinomas had a significantly higher p21WAF1/CIP1 expression compared with normal placentas and partial hydatidiform moles (p < 0.001); there was no difference between placentas and partial hydatidiform moles. No correlation between p21WAF1/CIP1 expression and either the proliferation (Ki67) index (p = 0.34) or p53 protein accumulation (p = 0.68) was demonstrated. There was no significant difference (p > 0.05) in p21WAF1/CIP1 expression between the 17 patients who developed persistent gestational trophoblastic disease and those who did not. CONCLUSIONS: This study suggests that p21WAF1/CIP1 expression in trophoblastic disease may be induced by a p53 independent pathway. The proliferative activity of gestational trophoblastic diseases might not be determined solely by the control of the cell cycle operated by p21WAF1/CIP1. p21WAF1/CIP1 expression is not an accurate prognostic indicator of gestational trophoblastic disease.

Biomarkers, Tumor↗
PubMed1998

Tumour markers and their prognostic value in adenocarcinoma of the cervix.

Ninety-one patients with adenocarcinoma of the cervix had 4 tumour markers (TMs) assayed before treatment. Serum squamous cell carcinoma antigen (SCC) (n = 91) was raised in 25%; tissue polypeptide antigen (TPA) (n = 78) was raised in 35%; carcinoembryonic antigen (CEA) (n = 34) was raised in 26% and CA 125 (n = 64) was raised in 27% of these patients. In 47 of these 91 patients (52%), 1 or more of the markers were raised. The percentage of patients with raised TM increased with advancing stage. Univariate survival analysis showed that age, stage, raised TPA, raised CA 125, and raised TMs (any one or more) were of prognostic significance. When multivariate analysis was done and each TM was individually analysed, only age, stage and raised CA 125 were of prognostic significance. Rising SCC or TPA or CA 125 levels in serial estimations correlated well with the occurrence of recurrence. Thus, pretreatment estimation of SCC, TPA and CA 125 can be used to identify the patients who can subsequently be monitored by serial TM estimation.

Adenocarcinoma↗
PubMed1997

Vaginal vault cytology in the routine follow-up of patients treated for endometrial carcinoma: is it useful?

Routine follow-up visits and vault cytology following treatment for endometrial carcinoma generates a considerable workload and takes up valuable resources. A review is needed to evaluate the usefulness of this practice. Eighty six patients treated and follow-up from January, 1987 to July, 1994 were reviewed. The standard follow-up protocol consisted of physical assessment and vault cytology every 1 to 2 months for the first 2 years, every 3 months for the third year and every 6 months thereafter for at least 5 years. Recurrences were defined as histologically proven disease after a 3-month disease free interval. Fourteen patients (17%) developed recurrences. Two of the 14 patients (14%) had local recurrences in the pelvis. Only 3 of these recurrences were detected during routine follow-up. Vault cytology was negative in all patients with recurrences even when the recurrence occurred locally in the pelvis. Traditional surveillance protocols were ineffective in the detection of recurrences. Vault cytology was particularly ineffective. It was calculated that 1 recurrence was detected for every 606 visits. In this age of budgetary constraints, alternative follow-up protocols should be explored.

Endometrial Neoplasms↗
PubMed1997

Prognostic significance of tumour markers in endometrial cancer.

Serum cancer antigen (CA) 125, CA15.3, CA19.9, carcinoembryonic antigen and tissue polypeptide antigen were analyzed in 100 normal subjects, 47 patients with benign gynaecological diseases and 97 patients with endometrial cancer. The incidence of individual elevated tumour markers (> 2SD) was 21.5-30.9% in cancer patients. Elevations of CA125 and CA15.3 were significantly associated with poor prognostic clinical factors. Univariate anaylses showed that elevated CA125, CA15.3 and CA19.9 were significantly associated with shorter survival. In multivariate analysis, CA15.3 was highly significant and had a larger hazard ratio. In conclusion, CA15.3 is a useful marker for the prognosis of patients with endometrial cancer.

Adult↗
PubMed1997

Effect of contralateral fog during refractive error assessment.

BACKGROUND: When assessing refractive error using static retinoscopy, it is conventional to fog the contralateral eye by approximately 2.00 D to prevent a blur-driven accommodative response stimulating consensual accommodation in the tested eye. However, the effect of higher amounts of contralateral fog (e.g., in a moderate-to-high uncorrected myopic individual) during refractive error assessment is unclear. METHODS: We assessed the refractive state in 16 visually normal myopic subjects while fogging the contralateral eye between zero and 6.00 D, in 1.00 D increments. Retinoscopy was simulated by shining a streak retinoscope light into the right eye, while simultaneously measuring the refractive state of this eye objectively. RESULTS: No significant change in mean refractive state was observed for up to 5.00 D of contralateral fog. But, 6.00 D of contralateral fog produced a significant mean increase in the myopic direction of 0.13 D. Also, in three subjects, a myopic shift of approximately 0.60 D was recorded after the introduction of 6.00 D of contralateral fog. Nevertheless, the magnitude of these largest shifts in refractive error are still smaller than the previously reported degree of repeatability of static retinoscopy. CONCLUSIONS: Since large amounts of contralateral fog produced only small and clinically insignificant changes in the refractive state, the practitioner merely needs to ensure that the nontested eye is indeed fogged. The magnitude of fog present will have only a minimal effect on the final result.

Adult↗
PubMed1996

Cloning of a pectate lyase gene from Xanthomonas campestris pv. malvacearum and comparison of its sequence relationship with pel genes of soft-rot Erwinia and Pseudomonas.

The cotton blight pathogen, Xanthomonas campestris pv. malvacearum strain B414, produces an extracellular pectate lyase (Pel) with an estimated M(r) of 41,000 and pI of 9.7. The gene coding for this enzyme initially identified in a 1.8-kb PstI genomic DNA fragment was cloned. The nucleotide sequences of this 1.8-kb fragment and two pel genes previously cloned from Pseudomonas fluorescens and P. viridiflava were determined. These pel genes encoded pre-Pel proteins consisting of 377 to 380 amino acids (a.a.). A signal peptide consisting of 26 to 29 a.a. was present at the amino-terminus of each pre-Pel. Multiple sequence analysis revealed that Pel proteins of non-Erwinia phytopathogens including Xanthomonas, Pseudomonas, and Bacillus constituted a distinct cluster, which showed 20 to 43% a.a. identity to the four established Pel families of Erwinia. Homologous pel sequences were detected in various pathovars or strains of X. campestris. All of these xanthomonads produced an alkaline Pel and were capable of causing soft-rot in potato tuber slices and green pepper fruits.

Amino Acid Sequence↗
PubMed1996

Developmental remodeling of the internal elastic lamina of rabbit arteries: effect of blood flow.

We examined remodeling of the internal elastic lamina (IEL) of rabbit arteries from 3 to 23 weeks of age. The IELs were fenestrated at all ages; however, the sizes of the fenestrae increased dramatically during postnatal development. Mean areas occupied by the individual fenestrae of the carotid artery IEL increased from 11.3 +/- 0.7 microns2 in 3-week-old rabbits to 61.2 +/- 5.5 microns2 in adult rabbits. The estimated number of fenestrae per vessel also increased greatly, from 2.68 x 10(5) to 9.27 x 10(5); however, the increased number of fenestrae did not keep pace with growth of the artery, since fenestrae per square millimeter decreased by 26%. Large increases in the size of fenestrae were also observed in the renal and iliac arteries, although greater decreases in fenestrae per square millimeter occurred with age (70% in iliac arteries). Morphological assessments suggested that enlarging fenestrae frequently fuse with neighbors. By contrast with other arteries, the IEL of the abdominal aorta was not a continuous fenestrated sheet in young animals, perhaps reflecting the extensive remodeling that this vessel undergoes in the postnatal period. We decreased common carotid blood flow by 70% in 5 rabbits at 10 weeks of age by ligating the ipsilateral external carotid artery, and we approximately doubled blood flow in 5 others at the same age, by contralateral common carotid ligation. At 15 weeks of age, fenestrae in the artery carrying increased flow were 39% larger than fenestrae in the control artery, whereas fenestrae were 53.5% smaller after 70% decreases in flow (P < .05). We conclude that flow-dependent enlargement of fenestrae contributes to developmental remodeling of the IEL. Remodeling of the IEL may also have important implications for transport of materials and cell-cell communication between the intima and media.

Animals↗
PubMed1996

Prognostic significance of serum tumour markers in carcinoma of the cervix.

PURPOSE: The purpose was to evaluate the prognostic significance of serum tumour markers and other potential prognostic factors in cervical cancer. MATERIALS AND METHODS: Five hundred and thirty-one patients with cervical cancer were studied. The pre-treatment levels of SCC (squamous cell carcinoma antigen), TPA (tissue polypeptide antigen), CEA (carcinoembryonic antigen), CA125 and hCG (human chorionic gonadotrophin) were assayed in these patients. Possible association between raised tumour markers and potential prognostic factors and their prognostic significance were sought by univariate and multivariate Cox analysis. RESULTS: SCC was raised in 65% of squamous cell carcinoma of the cervix and TPA was raised in 50%. Other markers were raised in less than 25%. No tumour markers were raised more than 30% in adenocarcinoma of the cervix. Raised SCC and TPA were related to advancing age, stage and grade of differentiation. Univariate analysis showed that age, stage, grade, raised SCC and TPA were significant prognostic factors on survival. Multivariate Cox analysis showed that stage was the most significant factor. CONCLUSION: Stage, age, grade of differentiation, raised pre-treatment levels of SCC and TPA were significant prognostic factors in cervical cancer using univariate analysis. However, only stage remains the most important independent prognostic factor in multivariate analysis. The prognostic value of these other factors in early stage disease needs further exploration.

Adenocarcinoma↗
PubMed1995

Recent infection with human immunodeficiency virus and possible rapid loss of CD4 T lymphocytes.

To assess a hypothesized trend that persons recently infected with the human immunodeficiency virus (HIV) may have more rapid declines in absolute CD4 T-lymphocyte (CD4+ cell) counts than those who were HIV-infected in earlier years, sequential CD4+ cell counts in three groups who had definable dates of HIV seroconversion between 1978 and 1992 were reviewed. The CD4+ cell counts examined were from some of the longest extant studies in the United States: 100 homosexual and bisexual men engaged in ongoing observational cohort studies in San Francisco, Denver, and Chicago since 1978 (Group 1); 89 persons in South Carolina infected after 1986 (Group 2); and 155 injecting drug users participating in an observational cohort study in Baltimore since 1988 (Group 3). For all groups, individually and in the aggregate, mean CD4+ cell counts declined rapidly in the first year after HIV infection and then stabilized. However, there was no clear trend for lower (or higher) CD4+ cell counts by fixed time after HIV seroconversion among those seroconverting in recent compared with earlier calendar years. These data do not support a hypothesized trend for more rapid loss of CD4 T lymphocytes--and, by implication, more pathogenic strains of HIV-1--among persons acquiring HIV infection in recent years.

CD4 Lymphocyte Count↗
PubMed1995

The spectrum of medical conditions and symptoms before acquired immunodeficiency syndrome in homosexual and bisexual men infected with the human immunodeficiency virus.

The full range and occurrence of medical conditions in persons infected with human immunodeficiency virus (HIV) before they develop illnesses that define acquired immunodeficiency syndrome (AIDS) have not been systematically or completely described. In a retrospective and prospective cohort study, 1,073 homosexual and bisexual men in three US cities were interviewed and examined twice per year from January 1988 to September 1992. Study participants were from San Francisco, California (273 HIV-seropositive and 432 HIV-seronegative men), Denver, Colorado (107 positive and 129 negative men), and Chicago, Illinois (54 positive and 78 negative men). A total of 305 HIV-positive men had specifiable dates of HIV seroconversion (mean of 15.3 months between the last negative and the first positive HIV antibody test). Besides much increased incidences of thrush (incidence relative risk (IRR) = 23.3) and hairy leukoplakia (IRR = 551), the following conditions also occurred significantly more frequently in HIV-positive men than in HIV-negative men: anal herpes (incidence density (ID) = 10.7/100 person-years; IRR = 7.7); sinusitis requiring antibiotics (ID = 6.2/100 person-years; IRR = 2.1); anal warts (ID = 5.8/100 person-years; IRR = 2.7); seborrhea (ID = 3.8/100 person-years; IRR = 6.6); community-acquired pneumonia (ID = 1.4/100 person-years; IRR = 2.7); skin cancers (ID = 1.0/100 person-years; IRR = 2.2); and seizures, often apparently "breaking through" prior anticonvulsant therapy (ID = 0.8/100 person-years; IRR = 5.6). First episodes of hairy leukoplakia, thrush, and skin cancer occurred at low mean CD4 counts (mean counts were less than 350 cells/microliters) and late in HIV infection (mean times were more than 8 years after HIV seroconversion). Many medical problems, some not widely appreciated, occur in HIV-infected men before they develop AIDS-defining illnesses, signifying considerable morbidity from pre-AIDS HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1995

Pharmacokinetic, pharmacodynamic, and pharmacotoxic profiles of recombinant-methionyl human interleukin-2[alanine-125] (r-metHuIL-2[ala-125]) following intravenous and subcutaneous administration in rats.

Comparative pharmacotoxicity studies in rats were performed to evaluate the response to r-metHuIL-2[ala-125] following 2 or 4 weeks of daily intravenous or subcutaneous administration, as well as to evaluate pharmacokinetic and pharmacodynamic responses. Pharmacokinetic analysis indicated that r-metHuIL-2[ala-125] showed high bioavailability and nonlinear concentration profiles. Pharmacodynamic responses to intravenous or subcutaneous dosing with r-metHuIL-2[ala-125], as measured by white blood cell counts, were comparable. Preclinical safety studies (6, 30, and 150 micrograms kg-1 day-1) indicated that r-metHuIL-2[ala-125], whether given intravenously or subcutaneously, was associated with increased circulating and infiltrating levels of lymphocytes and eosinophils. Bone marrow lymphoid hyperplasia and splenic extramedullary hematopoiesis were similarly observed in each study. This pattern of effects was considered an exaggerated pharmacodynamic response to r-metHuIL-2[ala-125]. Of further note was a histopathologic finding described as hepatocyte single cell necrosis which was observed following both intravenous and subcutaneous administration and was considered to be a toxic response to high doses of r-metHuIL-2[ala-125]. The no observable adverse effect level (NOAEL) for r-metHuIL-2[ala-125] via intravenous administration was 6 micrograms kg-1 day-1, while that for subcutaneous administration was 30 micrograms kg-1 day-1. Data herein present a form of rHuIL-2 with pharmacokinetic and pharmacodynamic profiles that are similar when given by these two systemic routes. Pharmacotoxic data, based on NOAELs, suggest that subcutaneous administration may be a preferred clinical route of administration.

Absorption↗
PubMed1994

The prognostic value of TPA and SCC in squamous cell carcinoma of the cervix.

Three hundred two patients with squamous cell carcinoma of the cervix had pretreatment measurement of serum levels of tissue polypeptide antigen (TPA) and squamous cell carcinoma antigen (SCC) to assess their prognostic value. Both markers were of prognostic significance in relation to stage, recurrence, and poor survival. The addition of TPA to SCC did not increase the percentage of patients with elevated pretreatment tumor marker level nor improve the prognostic significance. One hundred thirty-five of these patients also had serial assay of both markers during follow-up. Rise from normal or persistently elevated markers after treatment was associated with recurrence. The median lead time to recurrence was 2 months for SCC and 2.5 months for TPA. The addition of TPA to SCC in serial monitoring increased the sensitivity of detection of recurrence but decreased its specificity. The cost of assay of two markers over one may not justify the slight improvement in sensitivity of detection of recurrence. For squamous cell carcinoma of the cervix, SCC is a better tumor marker than TPA.

Adult↗
PubMed1994

Detection of heterozygous XY complete hydatidiform mole by chromosome in situ hybridization.

Complete hydatidiform mole has a substantial risk of developing persistent gestational trophoblastic disease (PTD). Whether heterozygous complete moles, arising from dispermy, have a higher risk of such progression than their homozygous counterparts is controversial. In this study, the frequency of heterozygous XY complete mole in 93 consecutive cases of histologically proven complete moles managed in Hong Kong was assessed by the technique of chromosome in situ hybridization (CISH) using DNA probes specific for the short arm of the Y chromosome. The incidence of Y-chromosome positive complete mole in the groups of patients with spontaneous remissions and the group with PTD with or without metastasis was also compared. The presence of Y chromosome was identified in 6 of the 93 cases (6.5%), and this incidence fell within the range reported in the world literature. Of these 93 patients, 5 patients defaulted follow-up, while 10 patients developed PTD, with evidence of metastasis in 2 of them. The presence of Y chromosome was also assessed in another 15 patients with documented metastatic PTD. It was found that CISH signals for Y chromosome were identified in 5.1% (4/78) of complete moles with spontaneous remission and 8% (2/25) with PTD with or without metastasis (P > 0.05). Y chromosome was detected in 5.9% (1/17) of the complete moles that developed metastasis and in 5.8% (5/86) of the complete moles that either developed spontaneous remission or developed nonmetastatic PTD (P > 0.05). There is no correlation between the presence of Y chromosome and development of persistent gestational trophoblastic disease.

Female↗
PubMed1994

Primary squamous cell carcinoma of fallopian tube.

We present a case of primary squamous cell carcinoma of the fallopian tube, the third case in the English literature. To make this diagnosis, metastasis from genital and nongenital squamous cell carcinoma should be excluded. This carcinoma reflects the multipotential differentiation of the müllerian duct system.

Carcinoma, Squamous Cell↗