Search PubMed⌕ Search

Biomedical subjects

C C Crawford

Publications and source records attributed to C C Crawford.

5 recordsLinked to original sources
PubMed2001

A systematic review of the quality of homeopathic clinical trials.

BACKGROUND: While a number of reviews of homeopathic clinical trials have been done, all have used methods dependent on allopathic diagnostic classifications foreign to homeopathic practice. In addition, no review has used established and validated quality criteria allowing direct comparison of the allopathic and homeopathic literature. METHODS: In a systematic review, we compared the quality of clinical-trial research in homeopathy to a sample of research on conventional therapies using a validated and system-neutral approach. All clinical trials on homeopathic treatments with parallel treatment groups published between 1945-1995 in English were selected. All were evaluated with an established set of 33 validity criteria previously validated on a broad range of health interventions across differing medical systems. Criteria covered statistical conclusion, internal, construct and external validity. Reliability of criteria application is greater than 0.95. RESULTS: 59 studies met the inclusion criteria. Of these, 79% were from peer-reviewed journals, 29% used a placebo control, 51% used random assignment, and 86% failed to consider potentially confounding variables. The main validity problems were in measurement where 96% did not report the proportion of subjects screened, and 64% did not report attrition rate. 17% of subjects dropped out in studies where this was reported. There was practically no replication of or overlap in the conditions studied and most studies were relatively small and done at a single-site. Compared to research on conventional therapies the overall quality of studies in homeopathy was worse and only slightly improved in more recent years. CONCLUSIONS: Clinical homeopathic research is clearly in its infancy with most studies using poor sampling and measurement techniques, few subjects, single sites and no replication. Many of these problems are correctable even within a "holistic" paradigm given sufficient research expertise, support and methods.

Clinical Trials as Topic↗
PubMed1984

The 1981 United States survey of cardiac pacing practices.

A survey of physicians implanting pacemakers was conducted to obtain a profile of permanent cardiac pacing practices in the United States during 1981. Questionnaires were mailed to 5,832 implanters with 765 responses (13%) received and 680 analyzed. It was estimated that there were approximately 5,600 physicians, 66% surgeons and 34% nonsurgeons, implanting pacemakers at 3,670 centers. About 118,000 new primary implants were performed, or 518 per million population. Only 17% of implantation procedures in 1981 were replacements compared with 31% in 1978. Roughly half the respondents worked in teams, most implanting from 46 to 55 pacemakers annually. The chief indications for permanent pacing were sick sinus syndrome (48%) and impairment of conduction in the atrioventricular node and His-Purkinje system (42%). Ninety-five percent of pacing leads were implanted transvenously. Seventy percent of the respondents had had experience with atrial and dual-chamber pacemakers, used largely to increase cardiac output. The use of ventricular demand (VVI) pacing decreased accordingly from 91% in 1975 to 84% in 1981. Although approximately 90% of primary pacemakers were programmable to some degree, almost half were not reprogrammed within the first 3 months after implantation and 30% were never reprogrammed. Most patients (85%) were followed up by transtelephonic electrocardiographic monitoring, 68% in conjunction with private office visits. The respondents estimated that dual-chamber pacing, accounting for 10% of implants in 1981, would increase to 37% by 1985. Early electrode malfunctions were less frequent when implantation was performed by high volume and solo implanters, and in public and community hospitals. It is concluded that periodic surveys of this type disclose important trends in the practice of cardiac pacing.

Cardiac Surgical Procedures↗
PubMed1968

Amino acid flux in an estuary.

Dissolved organic matter in York River estuary included 38 micrograms of free amino acids per liter. The highest concentrations were of glycine, serine, and ornithine. Of the 14 amino acids studied for uptake by planktonic bacteria, glycine, methionine, and serine had the greatest flux rates. The total amino acid flux represented from 1 to 10 percent of the daily photosynthetic carbon fixation.

Amino Acids↗