Biomedical subjects

L C Wong

Publications and source records attributed to L C Wong.

At least 73 records · Page 4Linked to original sources

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

Dose-tumor response of carcinoma of cervix: an analysis of 594 patients treated by radiotherapy.

This is a retrospective study of 594 histologically proven carcinomas of the uterine cervix treated with radiotherapy alone between January 1970 and December 1986. The age of this group of patients ranged from 22 to 86 years, and the median age was 57 years. There were 544 (91.6%) patients with squamous carcinoma and 36 (6.1%) with adenocarcinoma. There were 24 (4.0%) patients who were treated by two sessions of intracavitary brachytherapy only using intrauterine tandem and vaginal ovoids; 513 (86.4%) patients received whole pelvis irradiation followed by two sessions of brachytherapy at 1-week intervals, with or without additional boost to the parametrium. The dose to point A ranged from 40 to 100.9 Gy for the patients with stage IB to IIIB disease. The 5- and 10-year survival for stages IB, IIA, IIB, IIIA, and IIIB were 90.0, 82.1, 72.0, 50.0, 51.5, and 86.9, 71.0, 67.5, 41.7, and 46.9%, respectively. There was no long-term survivor for stage IV disease; the median survivals for patients with stages IVA and IVB were 15.2 and 9.3 months, respectively. Dose response was demonstrated for stages IIB and III tumors; dose to point A greater than 85 Gy was associated with better central control (P = 0.0036 and 0.0234, respectively). However, further increase in dose to point A beyond 85 Gy was not associated with improvement in central control (P = 0.3128 and 0.3394, respectively, for stages IIB and III). It was also found that the occurrences of rectosigmoid and bladder complications were correlated with the rectal and point A dose. Thus, for these patients, there is no need to increase the dose to point A beyond 85 Gy so that the risk of radiation sequelae can be cut down.

Actuarial Analysis↗

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

Use of prophylactic antibiotics in patients with carcinoma of the cervix receiving intracavitary radium insertion.

The efficacy was studied of prophylactic antibiotics in preventing febrile morbidity in patients with carcinoma of the cervix undergoing intracavitary radium insertions. Of 93 consecutive patients who had completed external irradiation and two intracavitary radium insertions, 63 (67.74%) had fever over 37.5 degrees C and 19 (20.43%) had fever over 38 degrees C during radium insertion when prophylactic antibiotics were not given. When 3 gm cefoxitin was given over 24 hrs in divided doses as prophylaxis, 39 (41.93%) had fever over 37.5 degrees C and 8 (8.60%) had fever over 38 degrees C. The difference was found to be statistically significant for fever over 37.5 degrees C (p < 0.001) and fever over 38 degrees C (p < 0.05). There was no difference in the duration of fever in the two groups, but the use of antibiotic prophylaxis apparently decreased the need for subsequent therapeutic antibiotics from 13.98% to 4.30%. No difference in the febrile incidence was found when considering the size of the cervical tumour, the stage of the disease, or whether it was a first or second radium insertion, or whether the patient had her menopause already. Prophylactic antibiotics were also found to be more effective in preventing febrile morbidity over 37.5 degrees C in those receiving adjuvant chemotherapy as compared to the general study group (p < 0.025). We concluded that the use of prophylactic antibiotics has beneficial effect in decreasing febrile episodes during the period the radium was inserted, as well as in reducing subsequent need for therapeutic antibiotics, while its use in immunocompromised patients who are prone to sepsis may also be of advantage.

Adult↗

PubMed1992

Clinical significance of mucin production in post-irradiated cervical carcinoma.

Histological sections from 50 patients with clinical stage Ib to stage IIb squamous cell carcinoma of the cervix, initially treated by radiotherapy and followed by Wertheim hysterectomy, were reviewed and stained for mucin. The tissues from 17 (34%) of the patients contained no residual carcinoma. Mucin production was demonstrated in tumour tissue from 18 (55%) of the patients with residual tumour, none of who died of disease during the 5 to 10 years of follow up. Two patients who died of recurrent carcinoma had no mucin production in the post-irradiated tumour tissues. The presence of mucin in irradiated carcinoma of cervix seems to infer a better prognosis and this may prove useful in the follow-up of irradiated carcinomas.

Adult↗

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

Primary mixed neuroendocrine and mucinous carcinoma of the ovary.

A rare case of mixed carcinoma of ovary with a predominant malignant neuroendocrine and a lesser mucinous tumor component is described. Extensive areas of enteric-type epithelium containing endocrine cells were present in both the mucinous borderline tumor element and in the small foci of mucinous adenocarcinoma. Transition from the mucinous tumor to the malignant neuroendocrine component provides evidence for the derivation of some neuroendocrine or carcinoid tumors direct from mucinous tumors without necessarily being a component of a teratoma. Contrary to reported examples of mucinous carcinoid, the overgrowth and spread of the neuroendocrine component characterised the aggressive and lethal nature of this tumor.

Adenocarcinoma, Mucinous↗

PubMed1991

High-mobility group and other nonhistone substrates for nuclear histone N-acetyltransferase.

A variety of nonhistone proteins and polyamines has been studied for their substrate activity for nuclear histone N-acetyltransferase. Nonhistone chromatin high-mobility group (HMG) proteins are found to be as good a substrate for the enzyme as histones. The enzyme also acetylates spermidine and spermine. However, protamine, bovine serum albumin, and ubiquitin are not substrates. Chymotryptic peptides of histone and HMGs retained about 64% of the substrate activity, but trypsin treatment reduced the substrate activity by more than 85%. Both N-acetyltransferase activities for HMGs and histones are copurified through salt extraction, polyethylene glycol fractionation, and chromatography on DEAE-cellulose, phosphocellulose columns, and a HPLC anionic-exchange column. The highly purified nuclear histone acetyltransferase shows similar optimal pH and ping-pong kinetics for both HMGs and histones. The Km for HMG is 0.25 mg/ml. HMGs are able to accept the acetyl group from isolated acetyl-enzyme intermediate. Denatured gel analysis shows that HMG 1 and HMG 2 are the major proteins acetylated. High salt concentrations, mononucleotides, and DNA, which inhibit histone substrate activity of the enzyme, also inhibit HMG substrate activity. These observations suggest that there is a major nuclear N-acetyltransferase which is responsible for the acetylation of both histones and HMGs and perhaps also of spermine and spermidine. Thus the regulation of the structure and function of chromatin through postsynthetic acetylation can be achieved by a single nuclear N-acetyltransferase.

Acetylation↗

PubMed1990

A controlled trial of bestatin in hydatidiform mole.

A prospective randomized controlled trial was conducted to study whether Bestatin, an immunomodifier, can reduce the incidence of persistent gestational trophoblastic disease in patients with hydatidiform mole. A group of 21 patients (Bestatin group) received 30 mg Bestatin daily after evacuation of the hydatidiform mole. A second group of 23 patients (control group) did not receive any drug. Blood was taken for white cell counts, differential counts, lymphocyte subset counts (CD2+, CD4+, CD8+ and B cells) and natural killer cell activity before evacuation of the hydatidiform moles. The tests were repeated every 4 weeks after evacuation until the serum beta subunit of human chorionic gonadotropin (beta hCG) had returned to normal or until the patient had to receive chemotherapy because of persistent gestational trophoblastic disease. There was no significant difference in the age of the patients, the pre-evacuation serum beta hCG, or the gestational age between the two groups. Chemotherapy was needed by 6 patients in the Bestatin group (28.6%) and 3 patients in the control group (13%) because of persistent gestational trophoblastic disease. There was no significant difference in any of the immunological parameters between the two groups before or after evacuation. We conclude that Bestatin at this dosage does not improve the immunological functions or clinical outcome in patients with hydatidiform mole.

Adjuvants, Immunologic↗

PubMed1990

Serum squamous cell carcinoma antigen in the monitoring of radiotherapy treatment response in carcinoma of the cervix.

In this study, squamous cell carcinoma antigen (SCC) was detected in 96 of 157 patients with squamous cell carcinoma of the cervix and the percentage of patients with raised SCC levels increased with the stage of disease (P less than 0.01). The use of serial SCC assays and cervical biopsy histology during the course of radiotherapy to predict tumor response to irradiation was assessed. In patients who were given external irradiation before intracavitary radium, a high SCC level or the presence of viable tumor cells in the biopsy was found to be of no predictive value. However, at completion of radiotherapy, i.e., after intracavitary radium application, patients with persistently high SCC levels had a significantly higher incidence of residual tumor than patients whose SCC levels returned to normal (P less than 0.01). In 60% of patients with a persistently high SCC level, viable tumor was found in the cervical biopsy at the end of radiotherapy. On the other hand, only 5.4% of patients whose SCC level returned to normal had residual tumor.

Adult↗

PubMed1990

Etoposide combination chemotherapy in refractory ovarian malignant germ cell tumor.

Thirty-three patients with malignant germ cell tumor of the ovary received postoperative vincristine, dactinomycin, and cyclosphosphamide (VAC) treatment. Eight failed VAC treatment and received etoposide, bleomycin, and cisplatin (PEB) combination chemotherapy. Three were cured and remained disease free 24-79 months after completion of PEB therapy.

Carboplatin↗

PubMed1990

Placental site trophoblastic tumor: with features between an exaggerated placental site reaction and a placental site trophoblastic tumor.

Chorionic villi, whose presence in cases of trophoblastic disease is normally used to exclude both a choriocarcinoma and placental site trophoblastic tumor (PSTT), were present in the initial uterine curettage specimen of a trophoblastic tumor. The lesion shared morphologic features of both an exaggerated placental site reaction and a PSTT. There was infiltration of the posterior wall of the uterus by small clusters and isolated cells which had a prominent affinity for vessels and resembled a usual placental bed reaction. There was, however, deep involvement of myometrium with extension to the cervix, and the condition persisted for 5 months after uterine evacuation. Because different treatment is entailed, identification of this lesion as a tumor of nonvillous trophoblast is also of great importance in a region where the more usual forms of trophoblastic disease represent a declining but not infrequent event. When products of gestation are examined, the possibility of a PSTT should be considered and the clinician alerted if there is a suggestion of excessive intermediate trophoblastic activity, regardless of the presence of chorionic villi. While this may result in the unnecessary followup of some cases, it would permit, with the aid of serial beta-hCG and HPL levels, the earlier detection of PSTTs.

Adult↗

PubMed1990

Neonatal necrotizing enterocolitis associated with delta toxin-producing methicillin-resistant Staphylococcus aureus.

Delta toxin-producing coagulase-negative staphylococci previously have been associated with necrotizing enterocolitis in neonates. We identified three preterm infants (body weight, 845 +/- 59 g) infected with methicillin-resistant Staphylococcus aureus (MRSA) who had a similar clinical syndrome, characterized by pustular dermatitis, bacteremia and necrotizing enterocolitis accompanied by gastric residua, abdominal distention, hematochezia and pneumatosis intestinalis. MRSA was recovered from all three infants at infected skin sites, blood or venous catheters and from two of three infants in stool specimens. Two infants also had Staphylococcus epidermidis isolated from stool. All MRSA isolates had identical microbiologic profiles: four plasmids with identical molecular weights; coproduction of enterotoxins A and B; and the same antibiotic susceptibilities. Of one skin isolate, two blood isolates and two stool isolates of MRSA that were tested, all had characteristic delta toxin hemolytic activity. All culture supernatants of these isolates evaluated for delta toxin were positive by Western blot analysis. The two strains of S. epidermidis isolated from stool were negative for delta-like toxin by a standardized enzyme-linked immunoassay. The clustering of these cases, the similarity of the clinical syndrome, and the prior association of necrotizing enterocolitis with delta-like toxins produced by S. epidermidis, suggest that delta toxin-producing MRSA (or other S. aureus isolates) also may be etiologic agents in some cases of necrotizing enterocolitis in newborns.

Bacterial Toxins↗

PubMed1990

Vaginal metastases in gestational trophoblastic disease.

From 1976 to 1988, 320 patients with gestational trophoblastic disease were treated in the Department of Obstetrics and Gynaecology, University of Hong Kong. Eighteen patients had vaginal metastases. The clinical features and behaviour of the disease were analysed. The prognosis depends mainly on the extent of the disease. Similar favourable response to chemotherapy was observed in low-risk patients with vaginal metastases.

Adult↗

PubMed1990

Role of CA125 and abdominal pelvic computerized axial tomogram in the monitoring of chemotherapy treatment of ovarian cancer.

Twenty four patients with epithelial ovarian cancer, who were treated by chemotherapy after debulking surgery, were monitored by serial monthly CA125 estimation and half-yearly computerized axial tomogram (CAT) of abdomen and pelvis. The efficiency of these monitoring methods and that of clinical examination were compared. The use of CA125 alone was superior to the use of clinical assessment alone in the detection of tumor progression (p less than 0.01). The addition of the expensive routine half-yearly CAT examination did not improve the tumor detection rate (p less than 0.05). Hence, CAT examination should not be used routinely to detect recurrence of tumor in patients without a raised CA125 level. However, in patients with increased CA125 level, CAT examination had a place in locating and in determining the extent of the tumor which in selected patients may enable us to make changes in therapy without laparotomy and in other patients may help us to make a better assessment on whether further debulking is possible.

Adult↗

PubMed1989

4-epidoxorubicin in recurrent cervical cancer.

Thirty-eight patients with histologically proven recurrent cervical cancer were treated with epirubicin, an analogue of anthracycline. There were eight complete responders and ten partial responders. The overall response rate was 47.8%. The survival duration of the responders was significantly longer than that of the nonresponders. The optimal dose of epirubicin has yet to be determined. The dosage of 120 mg/m2 was well tolerated. The role of epirubicin as an adjuvant chemotherapeutic agent in the treatment of cervical cancer was discussed.

Adult↗

PubMed1989

Long-term follow-up of potentiation of radiotherapy by cis-platinum in advanced cervical cancer.

Between January 1982 and January 1983 all patients with advanced cervical cancer were randomized into three groups: radiotherapy only (group I), radiotherapy plus weekly cis-platinum (group II), and radiation plus twice-weekly cis-platinum (group III). Better initial central control was observed in group III patients. Long-term survival was similar in the three groups. Potentiation of radiotherapy with cis-platinum failed to show any significant improvement in long-term survival.

Cisplatin↗

PubMed1989

Use of serum squamous cell carcinoma antigen assays in chemotherapy treatment of cervical cancer.

Serum squamous cell carcinoma antigen levels of 15 patients with recurrent or progressive squamous cell carcinoma of the cervix on chemotherapy treatment were assayed. In 13 of these 15 patients (86.7%), clinical response was positive correlated with change in serum SCC level. A stationary or rising serum SCC level indicated that the disease is probably stationary or progressive and chemotherapy should be stopped or changed.

Adult↗