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Biomedical subjects

D E Baker

Publications and source records attributed to D E Baker.

At least 37 records · Page 2Linked to original sources
PubMed1987

Two-view specimen radiography in surgical biopsy of nonpalpable breast masses.

Nonpalpable, low-density, noncalcified lesions sometimes can be difficult to see on an initial specimen radiograph. In 57 consecutive wire localizations, 37 patients had obvious microcalcifications and did not require a second specimen radiograph. Twenty-six patients had nonpalpable, noncalcified lesions, and a second specimen radiograph was obtained in 24 of these. In four of these cases the initial specimen radiograph failed to show the suspected lesion, and a second specimen radiograph orthogonal to the original plane of orientation of the specimen showed the lesion to be contained within the biopsied material. Although it is seldom necessary to use this technique, it may obviate a second biopsy specimen as well as reduce operative time. We found that a second orthogonal specimen radiograph provided important information in 7% of cases.

Aged↗
PubMed1986

Postappendectomy fluid collections in children: incidence, nature, and evolution evaluated using US.

At the authors' medical center, most patients with postappendectomy fluid collections are treated conservatively. Thirty-two (15%) of 216 children underwent postoperative sonography following appendectomies. In ten patients (31%), a total of 16 fluid collections were found on the initial postoperative sonogram. In the seven patients (70%) whose fluid collections were confined to the pelvis, the condition was treated conservatively and it resolved in 2-9 weeks. In three patients, fluid collections required surgical drainage and proved to be abscesses. In two of the three patients, abscesses were multiple and widely distributed in the abdomen, and the patients were clinically ill. The authors conclude that clinically symptomatic fluid collections develop postoperatively in approximately 5% of children who have undergone appendectomy for acute appendicitis and that the size and course of the fluid collection can be objectively monitored using sonography. Such fluid collections confined to the pelvis ultimately resolve with conservative, nonoperative therapy, although resolution may take up to 2 months.

Abdomen↗
PubMed1986

Pitfall in MR imaging of lymphadenopathy after lymphangiography.

In two patients examined with magnetic resonance (MR) imaging after lymphangiography, opacified pelvic lymph nodes could not be distinguished from subcutaneous or retroperitoneal fat because of the short T1 and long T2 relaxation times of lymphangiographic contrast media. Opacified nodes removed from one patient had relaxation times similar to those of fat. Thus, assessment of lymphadenopathy with MR imaging should be performed before lymphangiography to obviate this potential pitfall.

Contrast Media↗
PubMed1985

Pentoxifylline: a new agent for intermittent claudication.

Pentoxifylline is approved by the Food and Drug Administration for the treatment of patients with intermittent claudication on the basis of chronic occlusive arterial disease of the limbs. It is not a substitute for surgical bypass or removal of arterial obstructions, but will improve function and symptoms of the disease state. The mechanism by which pentoxifylline works is not well known, but appears to be related to erythrocyte adenosine triphosphate (ATP) concentrations and the phosphorylation of erythrocyte membrane proteins, both mechanisms resulting in an improvement in erythrocyte flexibility. Efficacy studies indicate that pentoxifylline is significantly more effective than placebo or nylidrin therapy. Adverse reactions are mainly of the gastrointestinal type and are minimized by the use of a controlled-release dosage form.

Delayed-Action Preparations↗
PubMed1985

Compatibility of heparin sodium and morphine sulfate.

The compatibility of morphine sulfate and heparin sodium was studied in solutions of deionized water and 0.9% sodium chloride. Crystalline morphine sulfate was reconstituted and heparin sodium 100 or 200 units/mL was added. Duplicate samples with a final volume of 5 mL were prepared and stored at room temperature. Morphine sulfate concentrations were 1, 2, 5, and 10 mg/mL in each diluent with each heparin concentration. Samples were visually inspected immediately after preparation and at 0.5 and 24 hours; pH was tested before adding heparin and at 0.5 and 24 hours. Similar procedures were followed adding morphine to the heparin. Samples containing morphine sulfate 2 and 10 mg/mL were analyzed by high-performance liquid chromatography for morphine concentrations immediately before adding heparin and at 0.5 and 24 hours. Precipitate appeared immediately after the second drug was added in samples containing morphine sulfate 10 mg/mL at both heparin concentrations in the water admixtures. No precipitate formed in any solutions containing morphine concentrations of 5 mg/mL or less nor in any samples containing 0.9% sodium chloride. In both diluents, pH values decreased as morphine sulfate concentrations increased. Morphine sulfate concentrations decreased significantly in water admixtures but not in admixtures prepared with 0.9% sodium chloride solution. Morphine sulfate and heparin sodium are incompatible only at morphine concentrations greater than 5 mg/mL. The incompatibility can be prevented by using 0.9% sodium chloride as the admixture diluent.

Chemistry, Pharmaceutical↗
PubMed1984

Cerebrovascular permeability and delivery of gentamicin to normal brain and experimental brain abscess in rats.

Antibiotics vary widely in their ability to penetrate the blood-brain barrier. In studies of 70 rats, the permeability of the normal blood-brain barrier to gentamicin was shown to be poor. In experimental brain abscesses, during the cerebritic stage of development, the penetration of intravenous antibiotics was increased compared to normal brain but was very inconsistent. Antibiotic delivery to brain abscess was not significantly altered with the administration of high-dose steroids, but the macrophage and glial response was markedly decreased with high-dose steroid therapy. Reversible osmotic blood-brain barrier modification with mannitol increased the delivery of gentamicin both to brain abscess and to the surrounding brain. It also resulted in more consistent tissue drug levels. The clinical implications of these studies suggest that, because of the inconsistent delivery of gentamicin to brain abscess, the therapeutic efficacy of medical management alone may be quite variable. This mode of therapy could possibly increase the efficacy of medical management of brain abscesses, especially in patients with multiple or surgically inaccessible brain abscesses.

Animals↗
PubMed1979

Cadmium and the food chain: the effect of dietary cadmium on tissue composition in chicks and laying hens.

The cadmium content of body tissues and eggs was studied in broiler chicks and laying hens fed diets supplemented with 3, 12, and 48 microgram/g of cadmium. The 48 microgram/g level was selected as a slightly toxic level while the lower levels were felt to be representative of the amounts of cadmium which would occur in feedstuffs due to environmental contamination. All levels of cadmium resulted in increased cadmium content of kidney while only 12 and 48 microgram/g resulted in increases in the cadmium content of liver and muscle. As little as 3 microgram/g cadmium consistently increased the cadmium content of liver and muscle but this did not prove to be statistically significant. The transfer of dietary cadmium to the egg was found to be very low. Only the 48 microgram/g level resulted in an increase in cadmium content of the egg. This dietary treatment also resulted in reduced egg production and egg shell thickness.

Animal Feed↗
PubMed1979

Sewage sludge as a source of cadmium in soil-plant-animal systems.

The objective of this presentation is to relate the abundance and mobility of Cd in components of terrestrial ecosystems with implications for land utilization of sewage sludge. The uptake of Cd by crop plants is a function of the quantity of the element in the soil plus other soil factors affecting the Cd ion activity or electrochemical potential at the plant root surface. The natural abundance of Cd in soils has been reported as 0.5 mug/g which is higher than the background level of 0.2 mug/g found in soils studied in Pennsylvania. Experimental results indicate that the plant availability of Cd increases with each soil addition. While the plant availability of Cd is decreased by liming to increase soil pH, it has not been possible to add Cd salts or sewage sludge Cd without significantly increasing plant uptake. Field studies have shown that land application of sewage sludge can be expected to increase the Cd concentration of corn leaves from a range of 0.05-0.1 mug/g to 1-3 mug/g. Two years after the last application of sludge which added up to 10 ppm Cd to the surface soil, corn grain, sorghum grain, wheat grain, and potatoes showed a 10- to 15-fold increase in Cd over background levels. Studies were conducted with chicks, laying hens, and meadow voles (Microtus Pennsylvanias) to assess the impact of this increase in plant Cd upon the food chain. Corn and sorghum plants were grown on soils with either inorganic or sludge fertilizer for the purpose of producing herbage for use in feeding trials with meadow voles. Eight diets and a synthetic control diet were formulated to study the effect of source (plant vs. inorganic) of Cd on tissue accumulation. Significant accumulation of Cd occurred in kidney and liver, but not muscle, of voles fed diets containing sludge fertilized corn (1.09 mug/g) or sludge fertilized sorghum (2.76 mug/g). The source of Cd had little influence on tissue accumulation. In studies with broiler chicks and laying hens, natural diets containing 0.2 ppm Cd were supplemented with 3 ppm of this element. As with the meadow voles, Cd readily accumulated in liver and kidney. Although the results were not statistically significant, 3 ppm dietary Cd doubled muscle Cd content. There was no transfer of Cd to egg in a long term (12 month) experiment with laying hens. Soil management programs have been developed to maintain animal dietary levels of Cd at less than 1.0 mug/g from the use of sewage sludge on land in Pennsylvania. However, it is concluded that this level over time may cause a significant accumulation of Cd in animal tissues. Interpretation of these results in relation to those for human intake of Cd and the long range health effects of Cd is required for the proper monitoring of sewage sludge applications on land used for production of crops which enter the food chain.

Animals↗