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W L Greene

Publications and source records attributed to W L Greene.

12 recordsLinked to original sources
PubMed2000

Claims of equivalence in medical research: are they supported by the evidence?

BACKGROUND: Most clinical studies are done to show comparative superiority, but many reports now claim equivalence between the investigated entities. These assertions may not always be supported by the methods used and the results obtained. PURPOSE: To assess the justification and support for claims of clinical or therapeutic equivalence in medical journals. DATA SOURCES: A search of MEDLINE for articles published from 1992 through 1996. STUDY SELECTION: From 1209 citations that contained the word equivalence in the title or abstract or contained the Medical Subject Heading therapeutic equivalency, we excluded 1121 studies reporting nonoriginal research, purely laboratory or other nonhuman research, and studies in which equivalence was not the main claim. The remaining 88 eligible papers were evaluated for five methodologic attributes. DATA SYNTHESIS: Only 45 (51%) of the 88 reports were specifically aimed at studying equivalence; the others either tried to show superiority or did not state a research aim. The quantitative distinctions regarded as "equivalent" ranged from 0% to 21% for direct increments and from 0% to 76% for proportionate differences. An equivalence boundary was set and confirmed with an appropriate statistical test in only 23% of reports. In 67% of reports, equivalence was declared after a failed test for comparative superiority, and in 10%, the claim of equivalence was not statistically evaluated. The sample size needed to confirm results had been calculated in advance for only 33% of reports. Sample size was 20 patients per group or fewer in 25% of reports. CONCLUSIONS: Many studies of clinical equivalence do not set boundaries for equivalence. Claims of "difference" or "similarity" are often made not by thoughtful examination of the data but by tests of statistical significance that are often misapplied or accompanied by inadequate sample sizes. These methodologic flaws can lead to false claims, inconsistencies, and harm to patients.

Humans↗
PubMed1997

Insomnia.

Explore the source record for details and available documents.

Humans↗
PubMed1997

Zolpidem: distinct from triazolam?

OBJECTIVE: To review the literature that compares zolpidem with triazolam, with an emphasis on efficacy and safety in humans. DATA SOURCES: Information was retrieved from a MEDLINE search (1983-1996) of the English-language literature using the terms triazolam and zolpidem. STUDY SELECTION: Reports of clinical trials comparing the safety and efficacy of zolpidem and triazolam were included in this review. DATA EXTRACTION: Data were evaluated according to study design, efficacy, and adverse effects. Pertinent information was selected and the data synthesized into a review format. DATA SYNTHESIS: Zolpidem and triazolam have similar pharmacokinetic and pharmacodynamic effects in humans. Clinical trials have shown that usually recommended, equipotent dosages of zolpidem and triazolam do not differ with respect to pharmacokinetics, efficacy, tolerability, residual effects, memory impairment, rebound insomnia, abuse potential, or other adverse effects. CONCLUSIONS: Zolpidem offers no distinct therapeutic advantage over triazolam for the treatment of insomnia.

Humans↗
PubMed1991

Getting the best price from health plans. Legal pitfalls of physician cooperation.

Antitrust laws place significant limits on collective action among independent practicing physicians. The lawful options most likely to appeal to physicians include the complete merger of physician practices or the significant involvement of a physician or group in a partially integrated legitimate joint venture, such as a provider-sponsored PPO. Neither activity should be undertaken without the assistance of legal counsel. Change in the overall thrust of antitrust law is unlikely, and physicians must protect themselves from liability through careful business planning and the use of competent legal counsel.

Collective Bargaining↗
PubMed1988

The relative predictive performance of two theophylline pharmacokinetic dosing programs.

The predictive performance of 2 theophylline pharmacokinetic dosing programs (Abbott and Simkin) was evaluated using a group of 44 inpatients who had 2 serum concentrations (TSC) measured during hospitalization. Bias was assessed with the median prediction error (PE) and precision was assessed with the median absolute PE. The Abbott program was significantly less biased than the Simkin program in predicting the first TSC (PEs 0.1 and -1.3 micrograms/ml, respectively; p less than 0.05). No significant difference in bias was observed in predicting the second TSC, or in precision in predicting either the first or second TSC. Both programs exhibited small improvements in prediction precision when the first TSC was used to predict the second. Correlations of predicted versus measured TSC also improved with the second prediction. These programs may be useful in dosing theophylline; however, TSC monitoring and the application of sound clinical judgment are warranted.

Adult↗
PubMed1985

Oxygen chemoreception by carotid body cells in culture.

Chemoreceptors for oxygen reside within the carotid body, but it is not known which cells actually sense hypoxia and by what mechanisms they transduce this information into afferent signals in the carotid sinus nerve. We have developed systems for the growth of glomus cells of the carotid body in dissociated cell culture. Here we demonstrate that, as in vivo, these cells contain the putative neurotransmitters dopamine, serotonin, and norepinephrine. Oxygen tension regulates the rate of dopamine secretion from the glomus cells. Similar to chemically stimulated catecholamine secretion from other adrenergic cells this hypoxia-stimulated release requires extracellular calcium. These results are compatible with the suggestion that the glomus cells of the carotid body are chemoreceptor cells and that they signal hypoxia by regulated secretion of dopamine.

Adrenal Medulla↗
PubMed1984

Cimetidine for stress-ulcer prophylaxis.

Although cimetidine is more effective than a placebo for the prophylaxis of stress-induced ulcers, it has no advantage over titrated antacid dosing. Several comparative studies even suggest that combining cimetidine with antacid is no more effective than use of full-dose antacid. Therefore, we recommend prophylactic use of cimetidine only when very large dosages of antacid are required, in order to minimize acid-base disturbances.

Antacids↗
PubMed1983

Cimetidine drug interactions.

Cimetidine is a widely used antiulcer medication that is also a potent inhibitor of the mixed-function oxidase enzymes in the liver. This effect results in a number of clinically important interactions with other drugs, which are now being appreciated. Other effects of cimetidine, such as raising of gastric pH, alteration of liver blood flow, or alterations in renal secretory mechanisms, may also contribute to or result in clinically significant interactions. Current data document appreciable alterations in the metabolism or excretion of warfarin, theophylline, phenytoin, lidocaine, certain beta-adrenoceptor antagonists, certain benzodiazepines, and probably narcotic analgesics and procainamide. Thus, effects of these drugs and serum levels, where available, should be more closely followed when used in combination with cimetidine. Cimetidine appears to exacerbate the myelosuppressive effects of the nitrosoureas, and may also significantly alter the absorption of ketoconazole. Though other drugs may affect the absorption or elimination of cimetidine, the clinical implication of these effects is uncertain.

Adrenergic beta-Antagonists↗