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Biomedical subjects

D Burdick

Publications and source records attributed to D Burdick.

At least 37 records · Page 2Linked to original sources

Accuracy of techniques to detect intraperitoneal abscess.

Three new diagnostic techniques, gray-scale ultrasonography, gallium-67 scanning (67Ga), and computed tomography (CT) were used in combination to detect intraperitoneal abscess in 30 patients. All 30 had sonography, 24 were scanned for 67Ga, and 15 underwent CT. Nine had three tests and 21 had two. Accuracy of results was evaluated by subsequent laparotomy in 16 and by clinical impression in the remainder. Ultrasound was accurate (true positive and true negative) in 12 of 16 (75%) operated patients, with 12% false-positive and 12% false-negative results. Gallium correctly diagnosed nine of 14 (64%) operated patients having 22% false-positive and 14% false-negative diagnoses. CT was accurate in five of seven (71%) patients evaluated by operation, with 14% false positives and 14% false negatives. Overall accuracies for both operated and clinical groups was ultrasound 57%, gallium 54%, and CT 67%, not significantly different results. Three tests agreed in only two of nine patients (22%), with no single test more accurate than another. Two tests agreed in 57%, with no test superior to another. It is concluded that ultrasonography, 67Ga scanning, and CT each have significant limits in diagnosing intra-abdominal pus. No single test is better than another. Disagreement among test results in the same patient obviates use of more than one technique in most instances.

Abscess↗

Compartment model approach to the estimation of tumor incidence and growth: investigation of a model of cancer latency.

Consideration is made of the problems involved in determining the effects of a chronic disease process, such as stomach cancer, on the observed mortality of the U.S. population. Specifically, since the time of initiation of tumor growth is unknown and the tumor becomes clinically manifest only after reaching considerable size, the early rate and pattern of tumor growth is unobserved. As a possible solution to the analysis of such problems, it is proposed to use stochastic compartment modelling techniques which deal with the problems of estimating the transition probabilities of a partially observed stochastic process. Implementation of the stochastic compartment techniques in this case depends on the selection of certain mathematical expressions from theories of carcinogenesis, epidemiologic studies and animal studies which allow the calculation of transition probabilities to unobserved states by making them explicit functions of time or age. Though the selection of the specific functions might be subject to debate, the general strategy of explicitly selecting such functions, and thereby exposing them for review in terms of biologic reasonableness and consistency with the data, seems to be a valid and useful methodology. Furthermore, various ways of viewing the model results (say from its internal behavior, e.g., from implied distributions of waiting times in various disease states) yield different insights into the various factors in carcinogenesis. The model, with parameters representing tumor incidence, time to tumor death given onset, genetic susceptibility to tumor growth and the effects of competing forces of mortality, is fitted to data on deaths due to stomach cancer for male U.S. residents age 25 and over in 1969. Two basic forms of the model, one with a waiting time distribution for occupants of the latent state and another with a single latency time, achieved excellent fits to the data. Examination of parameter estimates and compartment waiting time distributions are consistent with theoretical expectations and intuition. It is concluded that such strategies, involving the integration of clinical, experimental and vital statistics data into a comprehensive model of population carcinogenesis, are potentially powerful tools for investigation of the temporal dimensions of disease development in a human population.

Adult↗

Diagnosis of myocardial contusion in blunt chest trauma.

Of 20 patients with blunt chest trauma who underwent cardiac scanning, serial electrocardiography and cardiac monitoring to rule out myocardial contusion, four had positive cardiac scans. All four had electrocardiographic abnormalities: three had nonspecific ST-T wave changes, and the fourth had electrocardiographic evidence of an acute subendocardial infarction. Of the 16 patients with negative scans, five had normal electrocardiograms. In the remaining 11 patients, factors other than myocardial contusion were suspected causes of electrocardiographic abnormalities. On the basis of this data, electrocardiogram changes in the traumatized patient have various causes. Cardiac scanning appears to be a useful adjunct to electrocardiography in confirming the presence of myocardial contusion.

Adult↗

Growth of fungi in broiler houses.

The growth of fungi in broiler houses with and without histories of problems of unknown etiology or of mycotoxicoses was studied. Fungal growth data were obtained by the strip bait method and results expressed as frequency and relative density. The frequency and relative density of fungal growth of several species were higher in problem houses than in those without problems. In problem houses many known toxic fungi and several fungi of unknown toxicity were found growing, increasing in density and frequency during the rearing period. Houses without problems (control houses) were dominated throughout the rearing period by the growth of Scopulariopsis brevicaulis. This fungus grew infrequently and in low relative density in problem houses. There was no correlation between species composition and litter removal, pH, and moisture in problem and control houses. Fungi did not grow in inside feed hoppers or in dust on rafters in the broiler houses. One thermotolerant and two thermophilic species of fungi were found growing in outside feed bins. Three generalized fungal growth patterns in litter are described and theoretical consideration of environmental factors on these patterns are discussed.

Animals↗

Rehabilitation of the breast cancer patient.

No program concerned with the management of the patient with breast cancer can today be considered complete without including a program for effective rehabilitation. Programs for rehabilitation must consider the physical, functional, vocational, and sociopsychological needs of the breast cancer patient. More effective rehabilitation can be achieved by careful attention to details in the preoperative period, during the operation, in the immediate postoperative period, and in long-term followup. Attention of these details may be helpful in preventing significant lymphedema. To accomplish effective rehabilitation of the breast cancer patient, a team effort is required, working in harmony usually under the direction of the surgeon. An important member of the rehabilitation team is the mastectomy volunteer, who visits the new mastectomy patient in the immediate postoperative period as part of the American Cancer Society's "Reach to Recovery" program. All members of the medical team must develop a relationship with the patient and the family, which enables support to be provided with an attitude of hope and encouragement.

Breast↗

Metabolism of glutamic acid in Aspergillus ochraceus during the biosynthesis of ochratoxin A.

The uptake and utilization of glutamic acid in the biosynthesis of ochratoxin A by Aspergillus ochraceus were studied. Uniformly labeled L[14C]glutamic acid was incorporated into both the phenylalanine and isocoumarin moieties of ochratoxin A. Penicillic acid was also labeled. During the early stages of development, the amino acid was used mainly for the synthesis of ribonucleic acid and protein. A portion of glutamic acid was oxidized and was recovered as metabolic 14CO-2. The initial uptake velocity of glutamic acid decreased with age and was pH and temperature dependent. No relationship was found between the initial uptake velocities and ochratoxin A biosynthesis.

Aspergillus↗

Rumen bacterial interrelationships with plant tissue during degradation revealed by transmission electron microscopy.

The mode of rumen bacterial degradation of cell walls in coastal bermudagrass [Cynodon dactylon (L) Pers.] differed with the plant tissue type. Bacteria degraded thin, primary cell walls of mesophyll and phloem apparently by extracellular enzymes and without prior attachment; thick-walled bundle sheath and epidermal cells apparently were degraded after bacterial attachment, in some types by an extracellular substance, to the plant cell walls. Rumen bacteria split the nondegraded cuticle from the epidermis by preferentially attacking the cell just underneath the cuticle. The propensity for bacterial attachment to lignified cells of the vascular tissue was low, and bacterial degradation of these cells did not occur after 72 h of incubation.

Journal Article↗

Focal seizures, early veins, and increased flow. A clinical, angiographic, and radioisotopic correlation.

Prominent early draining veins have been found in angiograms of four patients studied during an acute benign illness characterized by repetitive focal motor seizures and prominent postictal neurologic deficits. Concomitant intravenous radionuclide gamma camera flow and static images showed increased relative perfusion with a slight positive static uptake on the involved side. Follow-up studies showed no evidence of these abnormalities. These angiographic and radioisotopic findings probably correlate with the clinically observed cortical hyperemia as part of, or subsequent to, focal motor seizures. Alternatively, these findings suggest the possibility that vascular occlusions may be the underlying cause of the patients' illness.

Adult↗

Production of penicillic acid and ochratoxin A on poultry feed by Aspergillus ochraceus: temperature and moisture requirements.

A strain of Aspergillus ochraceus Wilhelm, isolated from poultry feed, produced both penicillic acid and ochratoxin A. Studies demonstrating the ability of this fungus to colonize poultry feed and produce these two mycotoxins under various temperatures and moistures indicated that the interaction was complex. The optimal temperature for conidial development did not vary with moisture, but accumulation of both toxins did. A combination of low temperature, 15 or 22 C, and low moisture favored the production of penicillic acid, whereas high temperature, 30 C, and high moisture favored the production of ochratoxin A.

Animal Feed↗