Search PubMed⌕ Search

Biomedical subjects

R F Ambrose

Publications and source records attributed to R F Ambrose.

8 recordsLinked to original sources
PubMed2001

Trace metals in fish and invertebrates of three California coastal Wetlands.

Metal concentrations were measured in selected fish and invertebrate species from Mugu Lagoon, Malibu Lagoon and Ballona Wetlands in southern California in order to assess the extent of metal contamination in these three wetlands. Ranges of element concentrations (in microgram/g) found in biota were: Zn 12-650; Cu 1.9-440; Ni < 1-37; Cr < 1-55; Pb < 0.5-6.8; As < 1-8.5; Se < 1-3.8; Cd < 0.2-0.90; and Ag < 0.3-5.9. Relative to previous studies of California biota, the highest metal concentrations found were for chromium and nickel. The highest levels were in one of the two bottom-dwelling fish (juvenile Leptocottus armatus) (55 micrograms/g) and the two water-column fish sampled (Fundulus parvipinnis and Atherinops affinis) (30 and 24 micrograms/g). At Ballona Lagoon, elevated levels of copper and silver were found in the bivalve Tagelus californianus (440 and 5.9 micrograms/g). Chromium and nickel appeared to be most persistent in fish from Mugu (4.6-55 and 2.6-37 micrograms/g), the most northern site and an active military base, and Ballona (< 1-30 and < 1-16 micrograms/g), believed to be the most metal-contaminated site. Compared to previously measured metal concentrations in species of California coastal waters, these regions revealed higher levels of chromium, nickel, silver, arsenic, zinc, copper and, to a lesser extent, cadmium and selenium. Chromium and silver were present at high enough levels at all three sites to be considered environmental health hazards.

Animals↗
PubMed2001

A comparison of techniques for preparing fish fillet for ICP-AES multielemental analysis and the microwave digestion of whole fish.

Four catfish fillet homogenate treatments before multielemental metal analysis by simultaneous inductively coupled plasma/atomic emission spectroscopy were compared in triplicate. These treatments were: nitric acid wet-ashing by Parr bomb digestion; nitric acid wet-ashing by microwave digestion; tetramethylammonium hydroxide/nitric acid wet digestion; and dry-ashing. The tetramethylammonium hydroxide/nitric acid method was imprecise (coefficients of variation > 20%). The dry-ashing method was fast and sensitive but had low recoveries of 50% for spiked Pb and Al and was not as precise as the Parr bomb or microwave treatments. The Parr bomb method was the most precise method but was less sensitive than the microwave method which had nearly the same precision. The microwave method was then adapted to homogenates of small whole fish < or = 3 cm in length. The whole fish homogenate required more vigorous digestion conditions, and addition of more acid after the evaporative step because of the presence of less oxidizable and acid-soluble components than fillet. The whole fish homogenate was also more heterogeneous than catfish fillet. A quality assurance protocol to demonstrate homogenate uniformity is essential. The use of a non-specialized microwave oven system allowed precise results for fillet and whole fish homogenates.

Animals↗
PubMed1991

Rheumatoid arthritis patients and clinical drug trials. A case-control study.

In order to understand better why patients do or do not participate in clinical drug trials, we sent questionnaires to 100 patients with rheumatoid arthritis (RA) who participated in clinical drug trials at our center and to 100 RA patients with similar disease durations who did not participate in clinical drug trials at our center. We compared demographic, socioeconomic, and clinical characteristics of respondents. Those who participated and those who did not participate in clinical drug trials selected similar rank-order preferences of potential reasons for doing so. The most frequent reasons cited by participants and nonparticipants were physician recommendation (50% and 56%) and benefit to society (25% and 17%). Participants and nonparticipants were similar in reference to their age, sex, educational level, reported income per household, employment status, distance from the medical center, disease duration, number of tender joints, American Rheumatism Association functional class, and mean erythrocyte sedimentation rate variables. There were two differences between the groups: participants included a lower percentage of blacks and had a greater number of swollen joints. Even with those exceptions, we concluded that participants in clinical trials appear to be comparable to the general population of RA patients followed at our outpatient department.

Adult↗
PubMed1990

Rheumatology algorithms for primary care physicians.

Primary care physicians were trained on three rheumatology topics to assess the effectiveness of an educational strategy for continuing medical education. Algorithm training was shown to be at least as effective as that based on standard prose monographs. Both training groups improved their knowledge of patient management skills but there were no statistically significant differences between groups in the amount learned. When algorithms were used to design text materials, the designed texts required less study time than did the annotated clinical algorithms alone. That difference was significant for the shoulder pain materials (P less than 0.05) but not for the osteoporosis materials. The ratio of knowledge gained to study time was significantly higher for the algorithm group on the low back pain topic (P less than 0.05) but not for the other topics. Taped interview problems tests were studied as a method for assessing patient management skills related to problem-specific indicator conditions and were found to produce interrater reliability greater than 0.80 on five of the six tests.

Clinical Protocols↗
PubMed1989

Construction of clinical algorithms for educational programs.

Clinical algorithms have been used successfully in a variety of health care settings to assist health care professionals in the diagnosis and management of medical problems. In addition to their clinical applications, algorithms also serve as an instructional resource by themselves and when used in conjunction with other educational methodologies. A recommended algorithm development process is described for cancer educators who wish to take advantage of the unique contribution clinical algorithms can offer for their educational programs. Algorithm design conventions are reviewed and specific writing suggestions are offered for the guidance of educators who want to design their own clinical algorithms. Objections to clinical algorithms can often be attributed to a misunderstanding of their proper role, which is to facilitate, not dictate, the decision process and guide the application of management logic. Clinical algorithms are a valuable instructional resource that can be used in a wide range of educational settings from self-instruction units to the design of lecture presentations.

Algorithms↗
PubMed1989

Physician dropout.

Explore the source record for details and available documents.

Clinical Protocols↗