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Biomedical subjects

P L Zhao

Publications and source records attributed to P L Zhao.

9 recordsLinked to original sources
PubMed2002

A placebo and active comparator-controlled trial of rofecoxib for the treatment of rheumatoid arthritis.

OBJECTIVE: To evaluate the efficacy and tolerability of rofecoxib 25 mg and 50 mg once daily versus placebo and naproxen 500 mg twice daily in patients with RA. METHODS: Eligible patients were randomized (double-blind) to placebo (n = 289), rofecoxib 25 mg (n = 306), 50 mg (n = 286) once daily, or naproxen (n = 142) for 12 weeks. Efficacy assessments included the ACR core set, with prespecified primary endpoints: patient and investigator global assessments of disease activity, tender and swollen joint counts. Investigator-reported adverse experiences, routine laboratory and vital sign measurements were monitored. RESULTS: Rofecoxib 25 mg, 50 mg, and naproxen provided similar treatment effects, significantly different from placebo, consistent with improvement, for all primary endpoints. Effects were evident at the earliest assessment (week 2) and sustained for 12 weeks. All treatments were generally well-tolerated. CONCLUSIONS: Rofecoxib 25 mg once daily had similar efficacy to naproxen 500 mg twice daily (a standard dose). No additional benefit was seen with 50 mg rofecoxib.

Adult↗
PubMed2001

Gastrointestinal medications and procedures in osteoarthritis patients treated with rofecoxib compared with nonselective NSAIDs.

CONTEXT: Patients treated with nonselective cyclooxygenase inhibitors (nonsteroidal anti-inflammatory drugs [NSAIDs]) often experience dyspepsia and upper gastrointestinal (GI) adverse effects, and frequently require GI comedications and diagnostic procedures. OBJECTIVE: This study combined existing data to test the hypothesis that GI comedications and GI diagnostic procedures occur less frequently in osteoarthritis (OA) patients treated with rofecoxib compared with nonselective NSAIDs. DESIGN: Combined analysis of 8 randomized controlled clinical trials. SETTING: Rheumatology and general practice clinics. PATIENTS: Men and women aged 40 years and older with OA. INTERVENTIONS: Random assignment to placebo (n = 514), rofecoxib (n = 3357; 12.5, 25, or 50 mg daily combined; average 24.7 mg), or NSAIDs (n = 1564; ibuprofen 800 mg thrice daily, diclofenac 50 mg thrice daily, or nabumetone 1500 mg daily, combined). MAIN OUTCOME MEASURES: The cumulative incidence of patients using GI comedications (antacids, antispasmodics, antiflatulents, antiregurgitants, H2 antagonists, proton pump inhibitors, sucralfate, prostaglandins, other antiulcer therapy) and needing GI procedures (upper GI barium studies, upper or lower GI endoscopies) over 12 months. RESULTS: Compared with those treated with NSAIDs, patients treated with rofecoxib had a significantly lower incidence of GI comedication use (17.5% vs 27.0%, P <.001) and GI procedures (3.3% vs 5.3%, P =.02) over 12 months. Similar results were seen in analyses of protocols with placebo; in these studies, rates of GI comedications and procedures were highest with NSAIDs, while those with rofecoxib and placebo were similar to each other. CONCLUSIONS: OA patients treated with rofecoxib for up to 12 months required significantly less GI comedication and significantly fewer GI procedures than those treated with NSAIDs.

Adult↗
PubMed2000

Gastrointestinal tolerability of the selective cyclooxygenase-2 (COX-2) inhibitor rofecoxib compared with nonselective COX-1 and COX-2 inhibitors in osteoarthritis.

BACKGROUND: Most nonsteroidal anti-inflammatory drugs (NSAIDs) are nonselective cyclooxygenase (COX-1 and COX-2) inhibitors and are associated with a variety of upper gastrointestinal (GI) tract symptoms. The roles of COX-1 and COX-2 in the pathogenesis of these symptoms are unclear. To test whether COX-2 inhibition with rofecoxib would have greater GI tolerability than nonselective COX-1 and COX-2 inhibition, we compared the incidences of (1) treatment discontinuations for GI adverse events (AEs) and (2) prespecified dyspeptic-type GI AEs among patients with osteoarthritis treated with rofecoxib vs NSAIDs. METHODS: A prespecified, combined analysis of investigator-reported GI AEs in all 8 double-blind, randomized, phase 2b/3 osteoarthritis trials of rofecoxib was conducted. Patients included men and women with osteoarthritis (N = 5435); there was no upper age limit for entry. Treatments tested included rofecoxib, 12.5, 25, or 50 mg (combined), vs ibuprofen, diclofenac, or nabumetone (combined). Primary outcomes were the time (by survival analysis) to (1) treatment discontinuation due to GI AEs and (2) first reported dyspeptic-type GI AE. Between-treatment comparisons were made by log-rank test. RESULTS: The number of treatment discontinuations caused by GI AEs during 12 months was significantly lower (P=.02) with rofecoxib vs NSAIDs (8.2 vs 12.0 per 100 patient-years; relative risk, 0.70; 95% confidence interval, 0.52-0.94). The incidence of prespecified dyspeptic-type GI AEs during the first 6 months was significantly lower (P=.02) with rofecoxib vs NSAIDs (69.3 vs 85.2 per 100 patient-years; relative risk, 0.85; 95% confidence interval, 0.74-0.97). However, the difference between treatments in dyspeptic-type GI AEs was attenuated after 6 months. CONCLUSION: Rofecoxib was associated with a lower incidence of treatment discontinuations due to GI AEs over 12 months and a lower incidence of dyspeptic-type GI AEs over 6 months than treatment with nonselective COX inhibitors, or NSAIDs. Arch Intern Med. 2000;160:2998-3003

Abdominal Pain↗
PubMed2000

[Effects of different loading exercises on endogenous sex hormones and their metabolites].

Small loading and strengthening exercises were performed by 22 athletes(11 males and 11 females). The levels of serum hormones and their urinary metabolites were detected. The results showed that the serum levels of testosterone(T), free testosterone(FT) and 17-OH-progesterone(17-OHP) in male athletes exhibited no conspicuous changes. The excretion of their urinary androsteroids was significantly increased after exercises(P < 0.05), but significantly decreased in the recovery period(P < 0.05). After small loading exercises, their serum levels of T and FT revealed no obvious changes except those of 17-OHP which evidently increased in female athletes(P < 0.05); whereas the excretion of their urinary steroid hormones declined promptly after the exercises and in the recovery period (all P < 0.05). After strengthening exercises, the serum levels of T, FT and 17-OHP decreased distinctly in female athletes (all P < 0.05), the excretion of their urinary steroid hormones raised clearly after training and in the recovery period(P < 0.05). Therefore, it is suggested that the secretion and metabolism of sex hormones in the organism are influenced by the loading quality of sports during training, and sexual difference exists simultaneously.

17-alpha-Hydroxyprogesterone↗
PubMed2000

Cardiac L-type calcium channel alpha 1-subunit is increased by cyclic adenosine monophosphate: messenger RNA and protein expression in intact bone.

L-type calcium channels have been identified previously in both osteoblast-like osteosarcoma cell lines and primary cultures of osteoblasts using numerous techniques such as patch clamp recording, drug inhibited 45Ca2+ uptake, and Fura-2 measurements, but intact bone has not been investigated. Using reverse-transcription polymerase chain reaction (RT-PCR) we found that the three major isoforms of the alpha 1-subunit of L-type calcium channels, (alpha 1C, alpha 1D, and alpha 1S) are present in RNA extracted from ROS 17/2.8 osteosarcoma cells, rat femur, and rat skull. Sequencing of most of the alpha 1C-subunit from rat femur and ROS cells revealed that the splice variants in osteosarcoma cells and intact bone differ, but there are no unique sequence variations compared with those found in other tissues. Northern blot analysis of ROS cell RNA indicated that cyclic adenosine monophosphate (cAMP), but not 1 alpha, 25-dihydroxyvitamin D3, increased the messenger RNA (mRNA) of the alpha 1C-subunit. Western blot of ROS cell lysates revealed a band of more then 220 kDa, the amount of which increased in cells treated with cAMP. Using confocal microscopy combined with immunohistochemistry in ROS cells, intact bone, and cartilage, we found that the alpha 1C-subunit of this channel is expressed in osteoblasts and chondrocytes suggesting this channel may be a pathway for signal transduction in intact tissue, because it is in osteosarcoma cell lines and primary osteoblasts grown in tissue culture.

Animals↗
PubMed1999

Adverse upper gastrointestinal effects of rofecoxib compared with NSAIDs.

CONTEXT: Nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal (GI) toxic effects, such as upper GI tract perforations, symptomatic gastroduodenal ulcers, and upper GI tract bleeding (PUBs), are thought to be attributable to cyclooxygenase 1 (COX-1) inhibition. Rofecoxib specifically inhibits COX-2 and has demonstrated a low potential for causing upper GI injury. OBJECTIVE: To compare the incidence of PUBs in patients with osteoarthritis treated with rofecoxib vs NSAIDs. DESIGN: Prespecified analysis of all 8 double-blind, randomized phase 2b/3 rofecoxib osteoarthritis trials conducted from December 1996 through March 1998, including one 6-week dose-ranging study, two 6-week efficacy studies vs ibuprofen and placebo, two 1-year efficacy studies vs diclofenac, two 6-month endoscopy studies vs ibuprofen and placebo, and one 6-week efficacy study vs nabumetone and placebo. SETTING: Multinational sites. Participants Osteoarthritis patients (N = 5435; mean age, 63 years [range, 38-94 years]; 72.9% women). INTERVENTIONS: Rofecoxib, 12.5, 25, or 50 mg/d (n = 1209, 1603, and 545, respectively, combined) vs ibuprofen, 800 mg 3 times per day (n = 847), diclofenac, 50 mg 3 times per day (n = 590); or nabumetone, 1500 mg/d (n = 127) (combined). MAIN OUTCOME MEASURE: Cumulative incidence of PUBs for rofecoxib vs NSAIDs, based on survival analysis of time to first PUB diagnosis, using PUBs that met pre-specified criteria judged by a blinded, external adjudication committee. RESULTS: The incidence of PUBs over 12 months was significantly lower with rofecoxib vs NSAIDs (12-month cumulative incidence, 1.3% vs 1.8%; P = .046; rate per 100 patient-years, 1.33 vs 2.60; relative risk, 0.51; 95% confidence interval, 0.26-1.00). The cumulative incidence of dyspeptic GI adverse experiences was also lower with rofecoxib vs NSAIDS over 6 months (23.5% vs 25.5%; P = .02), after which the incidence rates converged. CONCLUSION: In a combined analysis of 8 trials of patients with osteoarthritis, treatment with rofecoxib was associated with a significantly lower incidence of PUBs than treatment with NSAIDs.

Adult↗
PubMed1997

Design for sample size re-estimation with interim data for double-blind clinical trials with binary outcomes.

Estimation of sample size in clinical trials requires knowledge of parameters that involve the treatment effect and variability, which are usually uncertain to medical researchers. The recent release within the European Union of a Note for Guidance from the Commission for Proprietary Medical Products (CPMP) highlights the importance of this issue. Most previous papers considered the case of continuous response variables that assume a normal distribution; some regarded the portion up to the interim stage as an 'internal pilot study' and required unblinding. In this paper, our concern is with the case of binary response variables, which is more difficult than the normal case since the mean and variance are not distinct parameters. We offer a design with a simple stratification strategy that enables us to verify and update the assumption of the response rates given initially in the protocol. The design provides a method to re-estimate the sample size based on interim data while preserving the trial's blinding. An illustrative numerical example and simulation results show slight effect on the type I error rate and the decision making characteristics on sample size adjustment.

Clinical Trials as Topic↗
PubMed1995

Sample size determination in combinatorial chemistry.

Combinatorial chemistry is gaining wide appeal as a technique for generating molecular diversity. Among the many combinatorial protocols, the split/recombine method is quite popular and particularly efficient at generating large libraries of compounds. In this process, polymer beads are equally divided into a series of pools and each pool is treated with a unique fragment; then the beads are recombined, mixed to uniformity, and redivided equally into a new series of pools for the subsequent couplings. The deviation from the ideal equimolar distribution of the final products is assessed by a special overall relative error, which is shown to be related to the Pearson statistic. Although the split/recombine sampling scheme is quite different from those used in analysis of categorical data, the Pearson statistic is shown to still follow a chi2 distribution. This result allows us to derive the required number of beads such that, with 99% confidence, the overall relative error is controlled to be less than a pregiven tolerable limit L1. In this paper, we also discuss another criterion, which determines the required number of beads so that, with 99% confidence, all individual relative errors are controlled to be less than a pregiven tolerable limit L2 (0 < L2 < 1).

Journal Article↗