Biomedical subjects

A N Cheung

Publications and source records attributed to A N Cheung.

At least 55 records · Page 3Linked to original sources

PubMed1994

The importance of extensive sampling and examination of cervix in suspected cases of amniotic fluid embolism.

Amniotic fluid embolism is an important complication of pregnancy with high mortality. The diagnosis of amniotic fluid embolism is generally made postmortem and rests upon the histological demonstration of amniotic fluid debris, including foetal epithelial squames and hair, in the pulmonary vasculature. We have made the diagnosis of amniotic fluid embolism in two patients by detection of the amniotic fluid debris in the blood vessels of the cervix in their hysterectomy specimens. These two patients presented with profuse primary postpartum haemorrhage and evidence of disseminated intravascular coagulation after uneventful deliveries. Amniotic fluid debris were only demonstrated in the blood vessels of the cervix but not in the corpus. This observation emphasizes the importance of a thorough histological examination of the cervix in cases of suspected amniotic fluid embolism.

Adult↗

PubMed1994

Pseudocarcinomatous hyperplasia of the fallopian tube associated with salpingitis. A report of 14 cases.

We describe 14 cases of pseudocarcinomatous changes in the fallopian tube characterized by florid epithelial hyperplasia and in half the cases mesothelial hyperplasia and associated with chronic salpingitis. The patients' ages ranged from 17 to 40 years. Seven had clinical evidence of pelvic inflammatory disease. Tubal enlargement or thickening were observed in 12 cases and pyosalpinx, tubo-ovarian abscesses, or hydrosalpinx, in six cases. All cases showed no gross evidence of tumor. The reactive atypical hyperplasia mimicked carcinoma microscopically because of a cribriform pattern, penetration of the tubal wall by hyperplastic epithelium, florid mesothelial hyperplasia, or a combination of these findings; epithelial papillae were present in the lymphatics in two cases. In five cases, an erroneous microscopic diagnosis of carcinoma had been made or seriously entertained initially, and one patient underwent a radical hysterectomy as a result. The typically young age of the patients, absence of a gross tumor, presence of severe chronic inflammation, lack of solid epithelial proliferation, mildness of nuclear atypia, and paucity of mitotic figures facilitated the differential diagnosis. Nine patients for whom follow-up information was available had no recurrence of tubal disease.

Adolescent↗

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↗

PubMed1994

Assessment of cell proliferation in hydatidiform mole using monoclonal antibody MIB1 to Ki-67 antigen.

AIMS: To assess the role of Ki67 immunoreactivity in predicting the clinical progress of hydatidiform mole. METHODS: Tissue from 87 hydatidiform moles, 11 normal first trimester placentas, 11 normal term placentas and 17 spontaneous abortions were examined for expression of Ki67 antigen, using the monoclonal antibody MIB1. RESULTS: Ki67 immunoreactivity was significantly higher in the tissue from normal first trimester placentas than in that from normal term placentas and spontaneous abortions. Among the 87 patients with hydatidiform moles studied, 20 developed persistent gestational trophoblastic disease and required subsequent treatment. There was no statistically significant difference in the Ki67 index between the 20 patients who developed persistent disease and those who did not. CONCLUSION: Hydatidiform moles which give rise to persistent trophoblastic disease do not have a higher proliferative rate than those which do not. The Ki67 index is not useful for predicting the prognosis of molar pregnancies.

Abortion, Spontaneous↗

PubMed1994

Expression of the p53 gene in trophoblastic cells in hydatidiform moles and normal human placentas.

In this study we compared the expression of p53 in six early placentas and eight hydatidiform moles using Northern blotting. A higher expression of p53 in hydatidiform moles as compared to normal placentas of comparable gestational age was observed. Immunohistochemical studies did not detect mutant protein of p53 in the hydatidiform moles. DNA sequencing was performed on four of the hydatidiform moles with increased expression of p53, but no mutations could be detected. The possible role of p53 in the pathogenesis of hydatidiform mole is discussed.

Base Sequence↗

PubMed1993

Fine-needle aspiration of cutaneous malakoplakia.

A 99-yr-old Chinese woman with cutaneous malakoplakia and concomitant urinary tract infection was reported. The patient presented with an ulcerated right lower quadrant mass and computerized tomography showed that it was limited to the skin and subcutaneous tissue with no extension to the pelvic or abdominal structures. The patient also suffered from urinary tract infection and was treated with oral norfloxacin. The ulcerated subcutaneous mass disappeared on follow-up visit 6 months after presentation. The cytologic (fine-needle aspiration), histologic (trucut biopsy) and ultrastructural features of cutaneous malakoplakia were described. The possible usefulness of fine-needle aspiration in the diagnosis of this condition was discussed.

Abdomen↗

PubMed1993

Epstein Barr virus in carcinoma of the cervix.

A group of young patients with invasive carcinoma of the cervix and an age-matched control group were investigated for the presence of Epstein Barr virus (EBV) DNA in cervical biopsies using the polymerase chain reaction. The carcinoma group was further analyzed to evaluate possible associations between the presence of EBV and other prognostic parameters, such as stage, lymph node involvement, and histological tumor type. EBV DNA was found in 20 of 40 (50%) of the carcinoma samples and in 20 of 39 (51%) of the cervical tissues in the control group (p > 0.5). No statistically significant relationship could be noted between the presence or absence of EBV DNA and the effects of other prognostic parameters. In comparison with other studies using similar techniques, this study documented a higher percentage of positive EBV cases in both normal and carcinoma cervical samples. In both groups there was a similar number of positive cases. These results suggest that theories on the possible role played by EBV in the pathogenesis of cervical carcinoma may need to be reconsidered.

Adult↗

PubMed1993

The significance of proliferating cell nuclear antigen in human trophoblastic disease: an immunohistochemical study.

The expression of proliferating cell nuclear antigen (PCNA) in human trophoblastic disease was assessed immunohistochemically in tissue from 29 spontaneous abortions, 33 partial moles, 40 complete moles and 23 choriocarcinomas using the monoclonal antibody PC10. PCNA immunoreactivity occurred predominantly in the cytotrophoblasts in each of the four types of tissues. Quantitative analysis showed that the choriocarcinoma group gave a statistically significant higher PCNA index than the other three. There was no significant difference between the groups of spontaneous abortion, partial or complete mole. Sixteen of the 73 patients with partial and complete moles developed persistent gestational trophoblastic disease and there was no significant difference between the patients requiring chemotherapy and those who did not. We conclude that choriocarcinoma has a significantly higher PCNA proliferative index whilst hydatidiform moles cannot be distinguished from abortions by such analysis. The PCNA index does not appear to be useful in predicting the progression of molar pregnancies to persistent trophoblastic diseases.

Abortion, Spontaneous↗

PubMed1993

Expression of c-myc and c-fms oncogenes in trophoblastic cells in hydatidiform mole and normal human placenta.

AIMS: To compare the expression of c-myc and c-fms proto-oncogenes in the placenta and hydatidiform mole. METHODS: Twelve hydatidiform moles and six induced abortion cases were collected. c-myc and c-fms proto-oncogene expression was analysed by northern blot hybridisation and immunohistochemical staining. RESULTS: The results of northern blot hybridisation analysis showed that c-fms was expressed more strongly in hydatidiform moles compared with normal placenta of similar gestational age. Moreover, c-fms mRNA concentrations increased with more advanced gestational age in moles but not in normal placentas. c-myc expression was very low in hydatidiform moles and normal placentas. Both oncogenes, however, had no direct correlation with the clinical course of the molar pregnancies. CONCLUSION: The difference in c-fms expression between hydatidiform moles and normal placentas suggests that c-fms may have a role in the development of molar pregnancies.

Antibodies, Monoclonal↗

PubMed1993

Epstein-Barr virus in carcinoma of the vulva.

AIMS: To detect the presence of Epstein-Barr virus (EBV) in cases of vulval carcinoma in Chinese patients living in Hong Kong. METHODS: Formalin fixed, paraffin wax embedded blocks from eight cases of vulval carcinoma and six age matched controls of non-neoplastic vulval tissue were analysed for the presence of EBV DNA using the polymerase chain reaction (PCR). RESULTS: EBV DNA was detected in only one of the eight cases of vulval carcinoma cases while it was detected in four out of the six control cases. CONCLUSIONS: There is no demonstrable association between EBV and vulval carcinoma. Detection of EBV in non-neoplastic vulval epithelium highlights its ubiquitous presence in the lower female genital tract.

Aged↗

PubMed1993

Cytomegalovirus infection of the gastrointestinal tract in non-AIDS patients.

Cytomegalovirus infection is usually reported in immunocompromised patients. In this study, 19 patients with cytomegalovirus (CMV) infection of the alimentary tract were reviewed, none of whom had acquired immunodeficiency syndrome. The patients' sex distribution was similar, and their ages ranged from 22 to 84 yr (mean = 61 yr). Only four patients had underlying diseases resulting in immunocompromise. The most common presentation was gastrointestinal bleeding, which occurred in 11 of the 19 patients (58%). Two patients had an unusual presentation of obstructive jaundice due to exuberant growth of granulation tissue at the ampulla of Vater. The majority of the lesions (n = 23) occurred in the large intestine and duodenum. Sixteen of these 23 lesions (69.6%) showed ulceration. Of these 16 lesions, six were diagnosed macroscopically as malignant by the endoscopists. It was observed histologically that a predominant epithelial distribution of the CMV inclusion bodies was associated with no or only mild inflammation, whereas a predominant endothelial distribution of the inclusion bodies was associated with ulcerative, severely inflamed lesions. From these observations, we conclude that ulceration probably is due to an ischemic process resulting from narrowing of capillary lumens by swollen endothelial cells affected by CMV infection. Concomitant infection by Candida species was found in only one patient. One patient had coexistent ulcerative colitis while another also suffered from graft-versus-host disease after bone marrow transplantation. In five of the eight cases with follow-up biopsies, the CMV inclusion bodies disappeared in subsequent biopsies. To conclude, a high degree of alertness is required for the histological diagnosis of unexpected CMV infection of the alimentary tract, in order to warrant correct treatment for the patients.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Rectal perforation after barium enema in a patient with cytomegalovirus colitis--a case report.

The very rare complication of rectal perforation during the barium enema of an immunocompetent Chinese man with cytomegalovirus (CMV) colitis is described. Rectal biopsy performed over three weeks earlier was unlikely to have been related to the perforation. Histopathological examination of the colonic mucosa showed features of active chronic colitis and CMV infection. After treatment with Ganciclovir, there was cessation of symptoms with eradication of the virus on repeat biopsy samples. It is suggested that presence of CMV colitis predisposed to rectal perforation. The clinical presentation, course of disease and response to treatment supported the concept of CMV as a primary aetiological agent. This complication should be borne in mind when performing barium enemas in patients with clinical features of colitis, especially if they are immunocompromised.

Aged↗

PubMed1992

Rapid death from thrombotic thrombocytopaenic purpura following caesarean section.

We report a case of rapid death from thrombotic thrombocytopaenic purpura (TTP) in a young pregnant lady who developed full blown symptoms soon after caesarean section. Extensive intramyocardial confluent haemorrhages and widespread microthrombi in heart, brain, adrenals and kidney were found at autopsy. Thrombotic thrombocytopaenic purpura is an uncommon condition, which carries a high fatality rate if untreated. Awareness of this syndrome together with its high risk of sudden death underlines the importance of rapid diagnosis and treatment.

Adrenal Cortex↗

PubMed1992

Human papillomavirus and its prognostic significance in invasive carcinoma of the cervix in young patients.

Of 1,200 Chinese patients treated for carcinoma of the cervix between 1975 and 1984, those aged 40 years (n = 70) or less had a poorer prognosis. Of the latter group, 71% had disease classified as less than International Federation of Gynecology and Obstetrics (FIGO) stage Ib, and in 91% the disease was less than stage IIa; however, the 5-year survival of the 45 patients with verified invasive carcinoma was 75% compared with 82% for the overall group. The polymerase chain reaction (PCR) was used to test for the presence of human papilloma virus (HPV) types 16 and 18 within paraffin-embedded tissue from the primary tumors. HPV-16 DNA sequences were detected in 69% of the cases, HPV-18 DNA sequences in 44%, and in 31% both HPV-16 and -18 DNA could be identified. Of the cases of invasive carcinoma, 82% (37 of 45) contained DNA of HPV types 16 and/or 18. The effects of the presence or absence of HPV DNA on known prognostic factors was investigated. Although the influence of traditional factors, especially lymph node involvement, was confirmed, careful statistical analysis could not demonstrate a prognostic influence for HPV-16/18.

Adult↗

PubMed1991

Prevalence of low and high risk human papillomavirus types in cervical cells from Hong Kong pregnant Chinese using filter in situ hybridization.

Filter in situ hybridization, using separate probes for human papillomavirus deoxyribonucleic acid types 6, 11, 16 and 18, was used to determine the prevailing HPV types amongst a group of pregnant Chinese women. This group had been previously identified using a mixture of probes for HPV types 6, 11, 16, 18, 31, 33, 35 (Virapap). Specimens from six of the eleven cases contained one HPV type (55%) while five were positive for two types (45%). The "low-risk" types (HBV6, 11) were identified as frequently as the "high-risk" types (HPV16, 18) in this study.

Cross-Sectional Studies↗

PubMedDate not supplied

Apoptotic and proliferative activities in first trimester placentae.

Apoptosis and cell proliferation are widely recognized to be important physiological processes which together maintain tissue homeostasis. The apoptotic and proliferative processes in 38 first trimester placentae were quantified using terminal deoxynucleotidyl transferase mediated dUTP nick end-labelling (TUNEL) and an antibody against Ki-67 antigen, respectively. In 14 cases, the estimation of apoptotic index was repeated with sections stained with haematoxylin and eosin by identifying the morphological features of apoptosis. We found that the indices obtained by either method correlated well with each other although a lower rate was obtained with the haematoxylin and eosin stained sections. Apoptosis was found in clusters mainly in syncytiotrophoblasts in association with fibrinoid deposits while proliferating activity was limited to cytotrophoblasts and stromal cells. A significant inverse correlation was observed between the proliferative index and gestational age as well as the apoptotic index. While the extent of apoptosis decreased with advanced gestational age, the correlation was not statistically significant. These findings provide a potential explanation for villous remodelling during trophoblastic invasion in early pregnancy.

Apoptosis↗

PubMedDate not supplied

Gastric carcinoma in young Hong Kong Chinese.

Gastric carcinomas usually occur in older people. Those occurring in the young are uncommon. The pathological and clinical features of gastric carcinomas were reviewed in 42 Chinese patients who were 35 years of age and younger. The data were obtained from the record files of the University Department of Pathology, Queen Mary Hospital for the period 1976-85. The patients comprised 4% of the total cases of gastric carcinomas in that period. These patients (age range: 20-35 years, mean: 30 years) showed a male to female ratio of 1:2.5 which differs from the usual male preponderance seen in gastric carcinoma. Among the 27 cases with known staging, 22 (81.5%) were stage III or IV. Twenty-five cases had an ulcerative appearance. All were adenocarcinomas and the majority (83.3%) were poorly differentiated. Associated dysplasia was found in 35 (83.3%) cases, although only 14 of these were in association with poorly differentiated adenocarcinomas. Intestinal metaplasia was found in 13 cases and, when present, involved less than 30% of the mucosa. Only two cases were of type III metaplasia. The findings show that gastric carcinoma in young Chinese tended to occur more frequently in females, presented at late stages, showed poor glandular differentiation, was frequently associated with gastric dysplasia and had minimal association with intestinal metaplasia.

Adenocarcinoma↗

PubMedDate not supplied

Abnormal expression of epidermal growth factor receptor and c-erbB2 in squamous cell carcinoma of the cervix: correlation with human papillomavirus and prognosis.

The aim of this study is to assess the expression of epidermal growth factor receptor (EGFR) and c-erbB2 and their correlation with human papillomavirus (HPV) status and prognosis in squamous cell carcinoma of the cervix. The expression of EGFR and c-erbB2 was studied at the protein level using the immunohistochemical (IHC) staining method, at the RNA level using the ribonuclease protection assay and at the DNA level using Southern blot and hybridization method. One hundred and one patients with squamous cell carcinoma of the cervix were recruited. Fifty-one patients were of stage 1B/2A and 50 patients were of stage 2B and above. Positive IHC stainings of EGFR and c-erbB2 proteins were found in 74.2 and 19.8% of cases, respectively. DNA amplifications of EGFR and c-erbB2 genes were detected in 35.4 and 17.2%, respectively. Of the patients showing positive EGFR and c-erbB2 staining, only 39.2 and 25%, respectively, showed DNA amplifications. RNA overexpression of EGFR or c-erbB2 was only detected in 2% of cervical cancers and was associated with positive staining and DNA amplifications. HPV was detected in 79.2% of the cases by HPV consensus primers L1, in 57.4% for HPV 16 and 27.7% for HPV 18. The abnormal expression of EGFR and c-erbB2 had no correlation with HPV detection and had no prognostic significance on survival.

Adult↗