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Biomedical subjects

D Chia

Publications and source records attributed to D Chia.

At least 19 recordsLinked to original sources
PubMed2004

Risk behaviours and benign prostatic hyperplasia.

OBJECTIVE: To identify risk factors for benign prostatic hyperplasia (BPH). SUBJECTS AND METHODS: Medical history data, including reported urological conditions and treatments, and risk factor data were collected from 34 694 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, a randomized controlled trial designed to evaluate methods for the early detection of cancer. RESULTS: Asian men had the lowest risks (odds ratio, 95% confidence interval) for nocturia (0.7, 0.5-0.9), physician-diagnosed BPH (0.3, 0.2-0.5) and transurethral prostatectomy (TURP, 0.2, 0.1-0.6), while risks for Whites and Blacks were similar for most measures of BPH. Greater alcohol intake was associated with decreased nocturia (P trend = 0.002), BPH (P trend < 0.001) and TURP (P trend < 0.001). Current tobacco use was associated with decreased nocturia (0.8, 0.7-0.9), BPH (0.7, 0.6-0.8) and TURP (0.6, 0.4-0.8) but dose-response patterns were weak. CONCLUSION: Asian-Americans have the lowest risk of clinical BPH. Alcohol and possibly cigarettes are related to a lower risk for BPH.

Age Distribution↗
PubMed2001

Relationship of demographic and clinical factors to free and total prostate-specific antigen.

OBJECTIVES: To characterize the role of demographic and clinical parameters in the measurements of prostate-specific antigen (PSA), free PSA (fPSA), and percent free PSA (%fPSA). METHODS: This was a cohort study of volunteers to a randomized screening trial. A central laboratory determined PSA and fPSA for the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. A baseline evaluation of free and total PSA was done for 7183 white, black, Asian, Hispanic, and other male volunteers, aged 55 to 74 years. Comparisons were made across racial and ethnic groups and across a set of clinical parameters from a baseline questionnaire. RESULTS: The median levels of serum PSA were less than 2.1 ng/mL in each age-race grouping of the study participants. The levels of free and total PSA were higher in black (n = 868, 12%) participants than in white (n = 4995, 70%) and Asian (n = 849, 11.8%) participants. Individuals who identified themselves as ethnically Hispanic (n = 339, 4.7%) had median PSA levels higher than whites who were not Hispanic. The free and total PSA levels increased with age, particularly among men 70 to 74 years old. However, the %fPSA levels showed less variation among the four racial groups or by age. The free and total PSA levels were higher among those who had a history of benign prostatic disease. CONCLUSIONS: Demographic (age and race/ethnicity) and clinical (history of benign prostatic disease) variables had a moderate effect on the measures of PSA and fPSA and very little effect on %fPSA.

Aged↗
PubMed2000

Design of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.

The objectives of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial are to determine in screenees ages 55-74 at entry whether screening with flexible sigmoidoscopy (60-cm sigmoidoscope) can reduce mortality from colorectal cancer, whether screening with chest X-ray can reduce mortality from lung cancer, whether screening men with digital rectal examination (DRE) plus serum prostate-specific antigen (PSA) can reduce mortality from prostate cancer, and whether screening women with CA125 and transvaginal ultrasound (TVU) can reduce mortality from ovarian cancer. Secondary objectives are to assess screening variables other than mortality for each of the interventions including sensitivity, specificity, and positive predictive value; to assess incidence, stage, and survival of cancer cases; and to investigate biologic and/or prognostic characterizations of tumor tissue and biochemical products as intermediate endpoints. The design is a multicenter, two-armed, randomized trial with 37,000 females and 37,000 males in each of the two arms. In the intervention arm, the PSA and CA125 tests are performed at entry, then annually for 5 years. The DRE, TVU, and chest X-ray exams are performed at entry and then annually for 3 years. Sigmoidoscopy is performed at entry and then at the 5-year point. Participants in the control arm follow their usual medical care practices. Participants will be followed for at least 13 years from randomization to ascertain all cancers of the prostate, lung, colorectum, and ovary, as well as deaths from all causes. A pilot phase was undertaken to assess the randomization, screening, and data collection procedures of the trial and to estimate design parameters such as compliance and contamination levels. This paper describes eligibility, consent, and other design features of the trial, randomization and screening procedures, and an outline of the follow-up procedures. Sample-size calculations are reported, and a data analysis plan is presented.

Colorectal Neoplasms↗
PubMed1998

The inhibitory effects of pravastatin on natural killer cell activity in vivo and on cytotoxic T lymphocyte activity in vitro.

BACKGROUND: We have reported that heart transplant recipients treated with pravastatin demonstrate decreases in the incidence of clinically severe acute rejection episodes, the incidence and progression of transplant coronary vasculopathy, and natural killer cytotoxicity. These patients also exhibited a significant improvement in 1-year allograft survival. Because of these clinical findings suggesting an immunosuppressive effect of pravastatin unique to transplant recipients and the unclear role of natural killer cells in allograft rejection, we postulated that pravastatin may exert its immunomodulatory effect by acting with cyclosporine to alter T lymphocyte function. METHODS: Twenty patients randomized into an ongoing trial of pravastatin after heart transplantation were monitored serially for natural killer cell cytotoxicity. In a separate experiment, lymphocytes isolated from normal volunteers were treated with various combinations of pravastatin and cyclosporine and tested for cytotoxic T lymphocyte toxicity in a one-way mixed lymphocyte reaction. RESULTS: Pravastatin-treated heart transplant recipients exhibited a decrease in natural killer cell cytotoxicity (9.8% mean natural killer cell cytotoxicity vs 22.1% in the control group, p < 0.01). In the one-way mixed lymphocyte reaction with blood obtained from control subjects, there was a synergistic inhibition of cytotoxic T lymphocyte activity when the cells were cultured in a combination of pravastatin and cyclosporine (20.3% mean cytotoxicity of target cells vs 41.4% in the control group, p < 0.01). CONCLUSIONS: Pravastatin exerts an immunosuppressive effect in heart transplant recipients as expressed by a reduction in rejection and natural killer cell cytotoxicity. Pravastatin and cyclosporine act synergistically to reduce cytotoxic T lymphocyte activity. This synergistic effect of pravastatin and cyclosporine may explain why this immunosuppressive effect is unique to transplant recipients.

Adjuvants, Immunologic↗
PubMed1997

Early fetal blood sampling--another available option for early prenatal diagnosis.

Fourteen cases had early fetal blood sampling (FBS) performed between 13 and 18 weeks gestation in the Antenatal Diagnostic Centre, National University Hospital, Singapore from Jan 1988 to December 1994. The indications were: a) ultrasound abnormality (n = 6), b) hydrops (n = 1), c) screening for blood disorders (n = 2), d) amnio results inconclusive or to confirm abnormal amnio results (n = 5). This article analyses retrospectively the early FBS procedure and its outcome. There were no procedure related fetal losses in this study. The reliable rapid results obtained following the procedure enabled the obstetrician to counsel the couple regarding the current pregnancy and advise them accordingly for the subsequent pregnancy. Thus we found it useful not only in our patients but also for patients from overseas who get their results within a week to plan their stay.

Blood Specimen Collection↗
PubMed1996

The effect of pravastatin on acute rejection after kidney transplantation--a pilot study.

Hyperlipidemia is an important complication of kidney transplantation affecting up to 74% of recipients. HMG-CoA reductase inhibitors are reported to provide safe and effective treatment for this problem. A recent study suggests that pravastatin, an HMG-CoA reductase inhibitor, also decreases the incidence of both clinically severe acute rejection episodes and natural killer cell cytotoxicity after orthotopic heart transplantation. We have performed a prospective randomized pilot study of the effect of pravastatin on these same parameters after cadaveric kidney transplantation. Graft recipients were randomized to receive pravastatin after transplantation or no pravastatin (24 patients in each group) in addition to routine cyclosporine and prednisone immunosuppression. Lipid levels, acute rejection episodes and serial natural killer cell cytotoxicities were followed for 4 months after the transplant. At the end of the study period, pravastatin had successfully controlled mean total cholesterol levels (202.6 +/- 9.3 vs. 236.5 +/- 11.9 mg/dl, P < 0.02), LDL levels (107.9 +/- 6.6 vs.149.6 +/- 10.7 mg/dl, P < 0.002), and triglyceride levels (118.8 +/- 14.2 vs. 157.2 +/- 13.8 mg/dl, P < 0.05). In addition, the pravastatin-treated group experienced a reduction in the incidence of biopsy-proven acute rejection episodes (25% vs. 58%, P = 0.01), the incidence of multiple rejections episodes (P < 0.05), and the use of both pulse methylprednisolone (P = 0.01) and OKT3 (P = 0.02). Mean natural killer cell cytotoxicity was similarly reduced (11.3 +/- 1.6 vs. 20.0 +/- 2.0% lysis of K562 target cells, P < 0.002). These data suggest that pravastatin exerts an additional immunosuppressive effect in kidney transplant recipients treated with cyclosporine-based immunosuppression.

Adult↗
PubMed1996

Role of transvaginal ultrasound color flow imaging and Doppler waveform analysis in differentiating between benign and malignant ovarian tumors.

This study was undertaken to assess the usefulness of ultrasound color flow imaging and Doppler waveform analysis in differentiating between benign and malignant ovarian tumors. From 1991 to 1993, 146 patients with 156 ovarian tumors underwent transvaginal scanning with color flow imaging and Doppler waveform analysis prior to surgery. All the ovarian tumors were removed surgically and confirmed histologically. The sensitivity and specificity of color flow imaging in identifying malignant ovarian tumors was 76.5% and 68%, respectively. Positive and negative predictive values were 40% and 91.2%, respectively. The addition of Doppler waveform analysis failed to produce statistically better results. Seven of the eight cases of ovarian cancer were missed by color Doppler. There were no solid areas present and malignancy was not suspected. Both modalities also failed to identify any case of ovarian cancer presenting as a simple cyst.

Adolescent↗
PubMed1996

Management of non-immune hydrops: 8 years' experience.

During a period of 8 years (1985-92), 100 fetuses were diagnosed to have non-immune hydrops on the basis of ultrasonographic findings and absence of rhesus isoimmunization. Both the mother and the fetus were thoroughly evaluated by a set protocol that included a detailed fetal abnormality scan with echocardiography and fetal blood sampling. A cause for non-immune hydrops could be identified in 81% of the fetuses. Cardiovascular abnormalities (23%) and alpha(1)-thalassemia (22%) were almost equally common etiological factors in the South-East Asian population under investigation. A chromosomal abnormality was detected in 10% of the fetuses with non-immune hydrops. Twenty-six fetuses were found to be suitable for in utero therapy. In utero therapy included one or more of the following: (1) fetal intravascular blood transfusion; (2) direct fetal drug therapy; and (3) fetal pleuroamniotic shunting. Eighteen of the 26 babies (69.2%) were alive and well at 1 month after delivery. It is concluded that in well-selected cases appropriate in utero fetal therapy can lead to significant improvement in fetal salvage.

Evaluation Studies as Topic↗
PubMed1996

The role of transvaginal ultrasonography and colour Doppler imaging in the detection of ectopic pregnancy.

OBJECTIVE: To assess the use of transvaginal ultrasound and colour Doppler imaging in the detection of ectopic pregnancy. MATERIALS AND METHODS: Seventy-one patients with suspected ectopic pregnancies had transvaginal sonography and colour Doppler imaging performed and 61 ectopic pregnancies were confirmed at surgery. Various ultrasound features on transvaginal B mode scanning were noted and the resistance index of peritrophoblastic flow in the adnexal masses computed. RESULTS: The use of transvaginal B mode imaging alone in the diagnosis of ectopic pregnancy achieved a sensitivity of 98% and a positive predictive value of 86%. The mean gestational age at time of diagnosis was 6 weeks 5 days (range 4 weeks to 13 weeks 2 days). The use of transvaginal colour flow imaging did not increase detection rates of ectopic pregnancy. The mean RI values for patients with or without ectopic pregnancy were almost identical. CONCLUSION: Colour Doppler imaging failed to improve on the results of transvaginal B mode sonography in the detection of ectopic pregnancy.

Adult↗
PubMed1996

Direct fetal therapy for hydrops secondary to congenital atrioventricular heart block.

BACKGROUND: The outcome for the fetus with hydrops fetalis secondary to complete congenital heart block is almost uniformly poor. Transplacental fetal therapy with inotropic drugs may be unreliable in the hydropic fetus. We describe our experience of direct fetal therapy with digoxin and furosemide in three cases. CASES: In the first two cases, fetal hydrops secondary to congenital heart block was detected at 33 and 31 weeks. Direct fetal therapy with digoxin and furosemide was given and the mothers received digoxin concurrently. The neonates were born normally at 35 weeks and 33 weeks; one required ventricular pacing, but both are currently alive and well. In the third case, fetal hydrops was detected at 24 weeks, when furosemide was used alone for direct fetal therapy. The mother developed chorioamnionitis at 29 weeks and was delivered by cesarean; the infant died of cardiac failure after 48 hours. CONCLUSION: Initial direct fetal therapy with digoxin and furosemide followed by transplacental treatment with digoxin and direct fetal therapy with diuretics might improve the perinatal salvage of hydropic fetuses with congenital heart block. Treatment must be individualized because development of infection and preterm labor might defeat the objective.

Adult↗
PubMed1996

Incidence of chromosomal abnormalities in 153 pregnancies with ultrasound detected fetal abnormalities.

One hundred and fifty-three patients with fetal abnormalities diagnosed on ultrasound were karyotyped between January 1992 and December 1993. There were 19 (12.4%) fetuses with chromosomal abnormalities. The risk of chromosomal aberrations in the malformed fetuses were increased in the presence of intrauterine growth retardation (15.4%), oligohydramnios (20%) and polyhydramnios (25%). Fetal karyotyping is thus essential in the management of such pregnancies.

Chromosome Aberrations↗
PubMed1995

Effect of pravastatin on outcomes after cardiac transplantation.

BACKGROUND: Hypercholesterolemia is common after cardiac transplantation and may contribute to the development of coronary vasculopathy. Pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has been shown to be effective and safe in lowering cholesterol levels after cardiac transplantation. Cell-culture studies using inhibitors of HMG-CoA reductase have suggested an immunosuppressive effect. METHODS: Early after transplantation, we randomly assigned consecutive patients to receive either pravastatin (47 patients) or no HMG-CoA reductase inhibitor (50 patients). RESULTS: Twelve months after transplantation, the pravastatin group had lower mean (+/- SD) cholesterol levels than the control group (193 +/- 36 vs. 248 +/- 49 mg per deciliter, P < 0.001), less frequent cardiac rejection accompanied by hemodynamic compromise (3 vs. 14 patients, P = 0.005), better survival (94 percent vs. 78 percent, P = 0.025), and a lower incidence of coronary vasculopathy in the transplant as determined by angiography and at autopsy (3 vs. 10 patients, P = 0.049). There was no difference between the two groups in the incidence of mild or moderate episodes of cardiac rejection. In a subgroup of study patients, intracoronary ultrasound measurements at base line and one year after transplantation showed less progression in the pravastatin group in maximal intimal thickness (0.11 +/- 0.09 mm, vs. 0.23 +/- 0.16 mm in the control group; P = 0.002) and in the intimal index (0.05 +/- 0.03 vs. 0.10 +/- 0.10, P = 0.031). In a subgroup of patients, the cytotoxicity of natural killer cells was lower in the pravastatin group than in the control group (9.8 percent vs. 22.2 percent specific lysis, P = 0.014). CONCLUSIONS: After cardiac transplantation, pravastatin had beneficial effects on cholesterol levels, the incidence of rejection causing hemodynamic compromise, one-year survival, and the incidence of coronary vasculopathy.

Cholesterol↗