Biomedical subjects
T K Chung
Publications and source records attributed to T K Chung.
Magnetic resonance venogram of intravenous leiomyomatosis.
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Effect of microbial phytase on ileal digestibility of phytate phosphorus, total phosphorus, and amino acids in a low-phosphorus diet for broilers.
The study aimed to assess the effect of a commercially available microbial phytase added to a corn-soybean meal diet on phytate P and total P in terminal ileal digesta as well as on true ileal amino acid digestibility. Three low-P diets containing 0, 500, or 750 U/kg of microbial phytase were fed to 21-d-old broiler chickens. Titanium dioxide was used as an indigestible marker. Ileal contents were collected from euthanized birds and analyzed, along with the diets, for total P, phytate P, and amino acids. Endogenous P determined at the terminal ileum was 446 +/- 59 mg/kg food dry matter (mean +/- SE). Endogenous ileal amino acids ranged from 219 +/- 33 mg/kg food dry matter for tryptophan to 1,255 +/- 166 mg/kg food dry matter for glutamic acid. Supplementation with microbial phytase resulted in a significantly (P < or = 0.05) greater phytate P disappearance (11% greater disappearance vs. unsupplemented control) from the terminal ileum. Similarly, true ileal total P digestibility was (P < or = 0.05) higher (10 to 12%) when microbial phytase was added. True ileal amino acid digestibility was significantly (P < or = 0.05) greater in the presence of microbial phytase for all the amino acids examined with the exception of methionine, tyrosine, histidine, and tryptophan. The mean increase in true ileal amino acid digestibility was 3.4%. The effect of phytase on true ileal phytate P, total P, and amino acid digestibility was similar for the 2 phytase inclusion levels tested. Microbial phytase improved phytate P and total P digestibility, as well as true ileal amino acid digestibility, for a corn-soybean diet.
The effect of microbial phytase on ileal phosphorus and amino acid digestibility in the broiler chicken.
1. The study aimed to assess the effect of a commercially available microbial phytase on phytate phosphorus and total phosphorus content at the terminal ileum as well as true ileal amino acid digestibility. 2. Five diets, each containing a different plant-based feedstuff, were supplemented with microbial phytase and fed, along with a non-supplemented corresponding diet, to 28-d-old broiler chickens, Chromic oxide was used as an indigestible marker. Ileal contents were collected and analysed, along with the diets, for total phosphorus, phytate phosphorus and amino acids. 3. Endogenous phosphorus determined at the terminal ileum was 272 +/- 108 mg/kg food dry matter (mean +/- SE). Endogenous ileal amino acid flows ranged from 58 +/- 10 mg/kg food dry matter for methionine to 568 +/- 47 mg/kg food dry matter for glutamic acid. 4. Supplementation with microbial phytase resulted in a significantly greater phytate P disappearance from the terminal ileum for rice bran (17% units), but not for soyabean meal, maize, wheat or rapeseed meal. Similarly total phosphorus digestibility was significantly (P < 0.05) higher when microbial phytase was added to the rice-bran-based diet but not for any of the other feedstuffs. 5. Amino acid digestibility was significantly greater in the presence of microbial phytase for all the amino acids examined in wheat, for several of the amino acids each in maize and rapeseed meal and for one amino acid in rice bran and soyabean meal. The average increase in amino acid digestibility for those amino acids affected, was 13, 6, 10, 7 and 12% units for wheat, maize, rapeseed meal, rice bran and soyabean meal, respectively. 6. It appears that microbial phytase improves phosphorus digestibility and amino acid digestibility for certain plant-based feedstuffs.
Aberrant expression of p21(WAF1/CIP1) and p27(KIP1) in cervical carcinoma.
An immuno-histochemical study of p21 and p27 expression in cervical carcinoma was performed in 73 patients. Positive p21 and p27 staining was detected in 35.6 and 11% of tumour tissues, respectively. p21 expression was significantly correlated with advanced disease stage and negative human papilloma virus infection whilst positive p27 staining was not correlated with any clinical and pathological parameters studied. Kaplan-Meier estimation indicated that survival might be related to disease stage, tumour grade and p21 expression. Cox regression analysis confirmed that advanced stage disease and poorly differentiated tumour are independent prognostic factors for cervical carcinoma.
Five-year compliance with hormone replacement therapy in postmenopausal Chinese women in Hong Kong.
OBJECTIVES: To assess 5-year compliance with hormone replacement therapy (HRT) in Hong Kong Chinese women and the reasons for long-term compliance or non-compliance. METHODS: A telephone survey using a standardized questionnaire was conducted in 187 postmenopausal women who had commenced HRT in a referral-only specialist clinic of a university teaching hospital 5 years previously. Over this 5-year period, the cohort had been referred out to primary care doctors once they had become stabilized on treatment. RESULTS: The 5-year compliance rate was 71.1%. The overall compliance rates were nearly the same from 2 and 5 years. 'Doctors' advice' was the most important reason for maintenance of long-term compliance, accounting for 88.0% of all compliant cases. The most frequent reason for non-compliance was that of the experience of side effects. Other important reasons were fear of cancer, fear of other side effects, and discouragement from other doctors. Overall, 16.0% of women expressed concern regarding potential side effects or risk of breast cancer. Younger age at menopause and at time of initial consultation, shorter duration of menopause at presentation and previous history of hysterectomy were associated with a higher degree of compliance at 5 years. Presence or absence of menopausal symptoms, on the other hand, was not a significant factor. CONCLUSIONS: The 5-year compliance rate in this cohort of Hong Kong Chinese women was comparable to that reported from predominantly Caucasian populations. The physicians' role in encouraging postmenopausal women to achieve long-term HRT compliance was observed.
Alteration of cyclin D1 and CDK4 gene in carcinoma of uterine cervix.
Amplification and overexpression of cyclin D1 and CDK4 genes in cervical carcinoma were studied by semi-quantitative differential polymerase chain reaction assay and an immunostaining technique, respectively. Amplifications of cyclin D1 and CDK4 genes were found in 24% (27/113) and 26% (29/112) of tumors, respectively. Overexpression of cyclin D1 and CDK4 was demonstrated in 32% (21/66) and 73% (45/62) of tumors, respectively. No tumor showed CDK4 gene mutation on single strand conformational polymorphism. Sixteen percent (8/49) of the tumor specimens showed neither amplification nor overexpression. Disease stage, tumor grade and overexpression of cyclin D1 were found to be independent poor prognostic factors in cervical carcinoma.
Preoperative hysteroscopic assessment of cervical invasion by endometrial carcinoma: a retrospective study.
OBJECTIVE: The aim of this study was to evaluate the efficacy of hysteroscopy, using normal saline (NS) or carbon dioxide (CO2) as the distention medium, in assessing tumor invasion of the uterine cervix by endometrial carcinoma. METHODS: A retrospective study was conducted in 200 consecutive patients with endometrial carcinoma diagnosed from 1993 to 2000. Prior to definitive surgical treatment, hysteroscopy was performed using either NS or CO2 as the distention medium to determine whether the tumor had spread to the cervix. The uterine specimens obtained after hysterectomies were cut open for gross examination. Tumor invasion of the cervix as determined by hysteroscopy and gross examinations was compared with the pathological findings. RESULTS: Tumor invasion of the cervix was found in 41 (20.5%) cases on pathological examination. Hysteroscopy has an accuracy of 92.5% (185/200), a sensitivity of 68.3% (28/41), and a specificity of 98.7% (157/159), with a PPV of 93.3% (28/30) and a NPV of 92.4% (157/170) in determining cervical involvement. Assessment by gross inspection had 93.0% (186/200) accuracy, 68.3% (28/41) sensitivity, 99.4% (158/159) specificity, 96.6% (28/29) PPV, and 92.4% (158/171) NPV. There was no significant difference between the two assessment methods. When the results of hysteroscopy performed with different distention mediums were compared, the use of NS had a higher accuracy in determining tumor spread to the cervix (96.8% vs 88.7%, P = 0.03) and NPV (96.4% vs 88.4%, P < 0.05) than the use of CO2. CONCLUSIONS: Hysteroscopic assessment and gross examination of the uterine specimen had similar efficacy in detecting cervical invasion by endometrial carcinoma. Hysteroscopic examination using NS is more accurate than that which uses CO2.
Screening for postnatal depression: are specific instruments mandatory?
BACKGROUND: Few studies have examined the utility of rating scales developed in non-puerperal context in detecting postnatal depression. This study evaluated the utility of the General Health Questionnaire (GHQ) and the Beck Depression Inventory (BDI) in screening for depression among recently delivered women in Hong Kong. METHODS: A prospective cohort of 145 Chinese women completed the GHQ, BDI and Edinburgh Postnatal Depression Scale (EPDS) 6 weeks after delivery. They were then assessed using the non-patient version of the Structured Clinical Interview for DSM-III-R (SCID-NP) to establish psychiatric diagnosis, against which the criterion validity of the GHQ and BDI was evaluated against this clinical diagnosis. The psychometric performance of the GHQ, BDI and EPDS in detecting postnatal depression was assessed using the receiver operating characteristic (ROC) curves. RESULTS: Both Chinese GHQ and BDI had satisfactory sensitivity and positive predictive value in detecting postnatal depression. Their receiver operating characteristic (ROC) curves were comparable to that of the EPDS. LIMITATION: The study was conducted in Chinese women using translated version of the rating scales. CONCLUSIONS: The GHQ and BDI are useful for detecting postnatal depression among recently delivered Chinese women. The results of this study suggest that rating scales developed in non-puerperal context may also be applicable for postnatal depression.
Microsatellite instability in cervical carcinoma.
OBJECTIVE: To investigate the incidence of microsatellite instability (MI) in cervical carcinoma and its relationship with clinicopathological characteristics. STUDY DESIGN: A retrospective study of 100 cases of cervical carcinoma. RESULTS: MI, defined as tumor-associated alterations in at least one of five dinucleotide microsatellite markers examined, was detected in 25% of the cervical carcinomas which were observed. There was a nonsignificant trend towards MI occurrence in higher grade tumors, more advanced stage and cases with poor clinical outcome. CONCLUSION: The results suggest that microsatellite instability is present in a subset of cervical carcinoma and may be an independent prognostic factor. Further research with more samples is required.
Neurologic injury after endovascular stent-graft and bilateral internal iliac artery embolization for infrarenal abdominal aortic aneurysm.
The authors report a rare neurologic complication after the implantation of a bifurcated stent-graft for abdominal aortic aneurysm. The stent-graft was extended to both external iliac arteries after embolization of both internal iliac arteries. The patient subsequently had weakness and numbness of both lower limbs with bowel and bladder incontinence. He probably had ischemic injury to the nerve roots or the lumbosacral plexus, which was related to extensive occlusion of their supplying arteries. The mechanism of spinal cord and neurologic ischemia after aortic stent-graft implantation is discussed.
A comparison of the psychologic impact and client satisfaction of surgical treatment with medical treatment of spontaneous abortion: a randomized controlled trial.
OBJECTIVE: The purpose of this study was to compare the psychologic impact and client satisfaction of routine surgical evacuation of the uterus with medical evacuation in cases of spontaneous abortion. STUDY DESIGN: This was a prospective, randomized controlled trial. Two hundred eighteen women who were admitted to a university teaching hospital after spontaneous abortion and who consented to the study were randomized to routine surgical evacuation or medical evacuation of the uterus with the use of misoprostol. General psychologic well-being, level of depression, fatigue symptoms, psychiatric morbidity, social functioning, client satisfaction, and acceptance were measured in the 2 groups. RESULTS: The 2 groups did not differ in any of the measured psychological outcomes. Significantly more participants who experienced successful evacuation of the uterus with the misoprostol protocol would choose the same mode of treatment if they were able to choose again. However, participants for whom the medical treatment failed to evacuate the uterus and subsequent surgical evacuation was required are significantly less satisfied with the treatment. CONCLUSION: Medical treatment of spontaneous abortion with misoprostol is psychologically safe and more compatible with the ethnomedical beliefs of our Chinese participants. Client satisfaction and acceptance should be taken into consideration in the evaluation of treatment outcomes.
Incomplete miscarriage: a randomized controlled trial comparing oral with vaginal misoprostol for medical evacuation.
BACKGROUND: A prospective randomized controlled trial was conducted to compare the efficacy and side-effects of vaginal versus oral misoprostol in the medical management of incomplete miscarriage. METHODS: Two hundred and one patients who miscarried consented to randomization using computer-generated randomization model prior to treatment. A total of 800 microg of misoprostol was given either vaginally or orally to the randomized subjects. A second dose was repeated 4 h later if the product of conception had not been passed. RESULTS: The incidence of complete uterine evacuation following vaginal and oral misoprostol was similar [(58/95) 61.1% versus (67/103) 64.4%]. There was a significantly decreased incidence of diarrhoea [(12/95) 13.6% versus (62/103) 65.3%, P < 0.01] with the use of vaginal misoprostol. CONCLUSIONS: Vaginal misoprostol was as effective as oral misoprostol in medical uterine evacuation in patients with incomplete miscarriage. There was also a reduction in the incidence of diarrhoea with the use of vaginal misoprostol.
Rate of rise in maternal plasma corticotrophin-releasing hormone and its relation to gestational length.
OBJECTIVE: To assess the relationship between rate of increase in maternal plasma corticotrophin-releasing hormone and gestational length. DESIGN: A prospective observational study. SETTING: Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Hong Kong. METHODS: Serial venous samples taken at four to six week intervals from 81 pregnant Chinese subjects were assayed for corticotrophin-releasing hormone concentrations. The investigators responsible for the laboratory assay were blinded to the obstetric outcome. RESULTS: A total of 380 blood samples were taken. Each subject provided three to seven samples (median = 5). Seven of the 81 subjects had preterm delivery. Maternal corticotrophin-releasing hormone levels increased exponentially as gestation advanced. A negative correlation between the rate of rise of logarithmic equivalence of corticotrophin-releasing hormone concentrations (Ln-corticotrophin releasing hormone) per week and the gestational age at delivery was demonstrated (r = -0.45, P < 0.001). The rate of increase of Ln-corticotrophin releasing hormone concentrations per week was also significantly greater for those who delivered preterm before 37 weeks compared with those with uncomplicated term deliveries (0.27 Vs 0.22, P = 0.018). CONCLUSIONS: The rate of increase in maternal plasma corticotrophin-releasing hormone is inversely proportional to gestational length. Results in a Chinese population confirm and extend results from previous caucasian populations. This study provides another piece of evidence on the close link between maternal plasma corticotrophin-releasing hormone and the timing of human parturition. As the hormone is synthesized by the placenta, it supports the suggestion that the human placenta has an important role in determining gestational length.
Clinical and prognostic significance of human papillomavirus in a Chinese population of cervical cancers.
OBJECTIVE: To investigate the clinical and prognostic significance of human papillomavirus (HPV) in a Chinese population of cervical cancers. METHODS: We studied 121 cervical cancer tissue samples from patients treated at our hospital. Identification and typing of HPV were done by polymerase chain reaction (PCR) using consensus primers MY11 and MY09 followed by direct DNA sequencing. The results were correlated with various clinical and prognostic parameters. RESULTS: We found HPV DNA in 95 (78.5%) cases, including HPV-16 in 59 (48.8%) and HPV-18 in 14 (11.6%) cases. chi(2) analysis revealed no significant correlation between the presence of HPV DNA and age at diagnosis, clinical stage, histologic type, tumor grading, 2-year and 5-year survival rate. Of the factors evaluated, age at diagnosis and histologic type were found to have a statistically significant relationship with HPV type. The mean age of the HPV-18 group was 48.6 years compared to 57.1 years for the HPV-16 group (p = 0.045) and 58.2 years for the HPV-negative group (p = 0.04). HPV-18 was detected more often in adenocarcinomas (AC) than in squamous cell carcinomas (SCC). Conversely HPV-16 was detected significantly more often in SCC (p < 0.0001). The HPV-negative group also had a higher incidence of SCC (p = 0.007). HPV-18-positive patients seemed to have more nodal involvement than both HPV-16-positive patients (45.5 vs. 20.8%) and HPV-negative patients (45.5 vs. 18.2%); however, it did not reach statistical significance. CONCLUSIONS: These observations suggest that the presence of HPV DNA does not bear any clinical or prognostic significance in a Chinese population of cervical cancers. HPV-18 is found more often in younger patients and is associated with AC.
Microsatellite instability, expression of hMSH2 and hMLH1 and HPV infection in cervical cancer and their clinico-pathological association.
Infection with specific genotypes of human papillomavirus (HPV) has been strongly implicated in cervical carcinogenesis. However, HPV infection alone is insufficient for malignant transformation of the cervical epithelium. An alteration of microsatellite repeats is the result of slippage owing to strand misalignment during DNA replication and is referred to as microsatellite instability (MSI). These defects in DNA repair pathways have been related to human carcinogenesis; however, the role of MSI in the tumorigenesis of cervical cancer remains unclear. The clinical and pathological features of cervical cancers which are MSI-positive have also not been fully characterized. This study investigated the prevalence of MSI in cervical cancer and its relationship to clinico-pathological characteristics and HPV infection. Polymerase chain reaction-based microsatellite assay combined with tissue microdissection was used to examine for MSI in 50 cervical squamous cell carcinomas in Hong Kong women. In addition, the immunohistochemical staining was performed to determine the expression of major DNA mismatch repair genes, hMSH2 and hMLH1. Six cases (12%) displayed a low frequency of MSI (MSL-L) showing MSI at one locus only in 5 loci examined. Seven cases (14%) showed a high frequency of MSI (MSI-H) having MSI at 2 or more loci. Grouping MSI-L and MSI-H cases together as MSI-positive, statistical analysis of HPV infection, tumor grade, clinical stage and clinical status failed to disclose differences between MSI-positive and MSI-negative cases (p > 0.05). However, MSI-H correlated with advanced stage of disease (p < 0.05). Individuals with MSI-H tumors appeared to have reduced overall survival compared to individuals with MSI-L and MSI-negative tumors, but the difference was not statistically significant (p = 0.059). An absence of either MSH2 or MLH1 expression was observed in 2 MSI-L and 4 MSI-H cases, respectively. The results suggest that MSI is present in a subgroup of cervical squamous cell carcinomas, and defects resulting in MSI may be related to tumor progression and possibly poor prognosis in cervical cancer.
Loss of heterozygosity at the short arm of chromosome 3 in microdissected cervical intraepithelial neoplasia.
Loss of heterozygosity (LOH) is a common genetic finding in many human neoplasms, including cervical cancer. The detection of LOH at specific loci in the precursor of cervical cancer, cervical intraepithelial neoplasia (CIN) may help in elucidating the evolution of this cancer, which has a clearly defined histological premalignant phase. However, molecular genetic investigation of CIN is difficult because many of the lesions are very small and sometimes ill defined topographically. In this study we analyzed eighteen polymorphic microsatellite repeats on chromosome 3p in CINs using a method of primer extension pre-amplification (PEP) for whole genome amplification combined with microdissection. These markers encompass chromosome region 3pter-3p12. LOH at one or more loci was detected in five (33%) out of the 15 informative cases with low grade CIN (CIN 1), while 22 (92%) out of 24 cases with high grade CIN (CIN 2 and 3) (P<0.01). The highest incidence (41%) of LOH was detected at locus D3S1038 (3p26.1-3p25.2). Frequent LOH (more than 20%) was also found at other loci including D3S1110 (3p25.3-3p25.1) (31%), D3S656 (3p25.1) (24%), D3S1076 (3p21.2-3p21.1) (29%), D3S1300 (3p21.1-3p14.2) (24%), D3S1600 (3p14.2-3p14.1) (24%), and D3S1079 (3p13) (25%). The results from this study taken together with others indicate that the genetic alterations on chromosome 3p are common in high grade of CIN and are probably early events in cervical carcinogenesis. Tumor suppressor gene(s) that play a role in cervical neoplasm may be located on the short arm of chromosome 3, likely at or near 3p26.1-25.1, 3p21.2-21.1, and 3p14.2-13.
Misoprostol's effect on uterine arterial blood flow and fetal heart rate in early pregnancy.
OBJECTIVE: To determine whether a single oral dose of misoprostol is associated with change in Doppler resistance indices (RIs) of the uterine artery in early pregnancy. METHODS: Forty pregnant women seeking legal termination of pregnancy at 7-15 completed gestational weeks were each given a single oral dose of 200 microg misoprostol. Resistance indices (A/B ratio) and pulsatility index (PI) of the uterine arteries (UA) and fetal heart rate (FHR) were assessed by Doppler ultrasound before and 1 hour after administration of misoprostol. RESULTS: Doppler RIs (UA-A/B and UA-PI) of the right and left uterine arteries increased significantly 1 hour after misoprostol administration. The right UA-A/B increased from 7.16 +/- 1.09 (mean +/- SEM) to 10.26 +/- 0.67 (P < .001), and the left UA-A/B increased from 7.40 +/- 0.72 to 9.21 +/- 0.82 (P = .04). The right UA-PI increased from 2.38 +/- 0.11 to 2.90 +/- 0.12 (P < .001), and the left UA-PI increased from 2.38 +/- 0.17 to 2.70 +/- 0.18 (P = .03). No significant changes in FHR were noted 1 hour after misoprostol administration. None of the fetuses died during that time. CONCLUSION: Doppler RIs of the uterine arteries increased significantly after single oral doses of misoprostol during the first trimester, implying a reduction in arterial blood flow. Those changes were not associated with fetal death, possibly explaining congenital abnormalities associated with misoprostol in early pregnancy.