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Biomedical subjects

D Pierce

Publications and source records attributed to D Pierce.

At least 19 recordsLinked to original sources
PubMed2005

Effects of prey type on specific dynamic action, growth, and mass conversion efficiencies in the horned frog, Ceratophrys cranwelli.

To be most energetically profitable, predators should ingest prey with the maximal nutritional benefit while minimizing the cost of processing. Therefore, when determining the quality of prey items, both the cost of processing and nutritional content must be considered. Specific dynamic action (SDA), the increase in metabolic rate associated with feeding in animals, is a significant processing cost that represents the total cost of digestion and assimilation of nutrients from prey. We examined the effects of an invertebrate diet (earthworms) and a vertebrate diet (newborn mice) on mass conversion efficiencies, growth, and SDA in the Chacoan horned frog, Ceratophrys cranwelli. We found the earthworm diet to be significantly lower in lipid, protein, and energy content when compared to the diet of newborn mice. Growth and mass conversion efficiencies were significantly higher in frogs fed newborn mice. However, mean SDA did not differ between frogs fed the two diets, a finding that contradicts many studies that indicate SDA increases with the protein content of the meal. Together, our results indicate that future studies evaluating the effect of meal type on bioenergetics of herpetofauna are warranted and may provide significant insight into the underlying factors driving SDA.

Animal Nutritional Physiological Phenomena↗
PubMed2000

Clinical practice guidelines and the cost of care. A growing alliance.

UNLABELLED: Healthcare policy, medical practice, and cost of care are no longer considered distinct entities. Each is an integral factor in determining not only what, but how, patient care will be delivered. Clinical practice guidelines are the lynchpin that connects them. This paper addresses the various components of the clinical practice guideline--cost alliance. OBJECTIVE: To examine the bidirectional influence of choice of care on costs and of cost of care on decision making. METHODS: The literature was used to identify cost-related factors that influence development of guidelines and change in physician practice behavior. In a MEDLINE search with modifiers to the keywords "clinical practice guidelines," particular attention was paid to identifying surveys of practitioners. An analysis, prompted by a recently published guideline, of treating penetrating intraperitoneal colon injuries by different surgical approaches (primary repair versus diverting colostomy) exemplified how implementation of a guideline can affect the cost of care. Inpatient cost estimates, adjusted for medical inflation and cost-to-charge ratios and reported in 1999 U.S. dollars, were developed using data from 1996 and 1997 discharge databases from California and Massachusetts. RESULTS: The results showed that a substantial savings in hospital costs was achieved when a primary repair surgical technique, as advocated by the guideline, was used. The effect of cost influences on the development of clinical practice guidelines was established by demonstrating the cyclical effect between usual and customary practices, guideline implementation, changing practice patterns, and the economic considerations influencing the process. CONCLUSIONS: A growing, albeit uneasy, alliance between costs and clinical practice guidelines is evident.

Colon↗
PubMed2000

A proposed method for the measurement of anesthetist care variability.

OBJECTIVE: Some critical events in anesthesiology occur as seemingly preventable misadventures, their exact origins indeterminable. Inexperienced anesthetists, anesthesia machine malfunctions, lack of vigilance and human error inevitably initiate some incidents. Anesthesia training improves recognition and decision-making. Avoiding crisis initiation and amelioration of those that do occur is one role of the consultant anesthesiologist. Safe patient care requires medical and procedural knowledge, technical expertise, and control of resources in a complex milieu. Anesthesia simulators are clinical laboratories where anesthetists can sharpen both cognitive and manual skills. Dynamic scenarios allow opportunities for anesthetists to explore and experience crises as they develop and apply their knowledge while attempting to manage these events. Simulator-based scenarios are reproducible and large amounts of useful data can be collected and saved. The authors hypothesize these data can be utilized to compare performance of anesthetists and to measure improvement of individual anesthetists over time. METHODS: We have designed "Stable Anesthesia," a prototypic scenario to test anesthetists' capabilities under the stress of performance guidelines. Three subjects performed anesthesia using the simulator and this protocol. Data from the simulator were archived by the system and analyzed by the authors. RESULTS: A simple mathematical analysis gave good separation of data from three subjects of different training level. CONCLUSIONS: It is suggested that the use of the techniques mentioned here may be of value in the development of a standardized testing protocol for anesthetists.

Anesthesiology↗
PubMed2000

Agrobacterium-mediated sorghum transformation.

Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a 'Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transformation experiments. A number of different transformation conditions were tested and a total of 131 stably transformed events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on transformation efficiency, with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably transformed sorghum plants. The Agrobacterium method we used yields a higher frequency of stable transformation that other methods reported previously.

Agrobacterium tumefaciens↗
PubMed2000

Perspective in pituitary adenomas: an end of the century review of tumorigenesis, diagnosis, and treatment.

Significant advances have been made in the molecular biological understanding of pituitary tumorigenesis. These advances will have an impact on the gene therapy of pituitary tumors in the coming century. Transsphenoidal surgery remains the mainstay of treatment for the majority of pituitary adenomas, with endoscopic surgery being used at some centers in select patients. Pharmacotherapy of pituitary adenomas has made great strides in the management of prolactinomas and GH-secreting pituitary adenomas. Finally, radiosurgery has become a very important adjuvant therapy in the treatment of hypersecreting pituitary adenomas.

Humans↗
PubMed1998

Establishment and characterization of primary gallbladder epithelial cell cultures in the prairie dog.

BACKGROUND: The prairie dog has become the established animal gallstone model. This species has a unique propensity to form cholesterol gallstones in response to dietary manipulations. The development of a reliable gallbladder cell culture technique is critical for understanding pathogenic mechanisms of gallstone formation. MATERIALS AND METHODS: Prairie dogs underwent laparotomy and cholecystectomy, followed by initiation of cell cultures. [3H]Thymidine incorporation was used to assess cell growth, and cell lines were assessed using routine histochemical and immunohistochemical staining. RESULTS: Cell yields from prairie dog gallbladders were 4-8 x 10(6) viable cells per animal with viability ranging from 80 to 95%. When plated at 5 x 10(5) cells/cm2, cell clusters, visible within 24 h, coalesced into confluent monolayers within 3-5 days. Cultures remained viable for 6-8 weeks and could be passed for three to four subcultures. Immunohistochemical staining demonstrated a high degree of epithelial purity with immunopositivity for AE1/AE3, and cytokeratin, with no vimentin positivity (mesenchymal antigen). Intracytoplasmic vacuoles demonstrated positive staining for Alcian blue, periodic acid-Schiff, and mucicarmine and an anti-gallbladder mucin antibody confirmed the presence of the glycoprotein mucin. CONCLUSIONS: This study demonstrates a reliable method for initiation and maintenance of prairie dog gallbladder epithelial cell cultures with a high degree of purity. This technique should allow further studies into the pathogenesis of cholesterol gallstones in this model.

Animals↗
PubMed1997

Complications of transsphenoidal surgery: results of a national survey, review of the literature, and personal experience.

OBJECTIVE: The primary objectives of this report were, first, to determine the number and incidence of complications of transsphenoidal surgery performed by a cross-section of neurosurgeons in the United States and, second, to ascertain the influence of the surgeon's experience with the procedure on the occurrence of these complications. The secondary objective was to review complications of transsphenoidal surgery from the standpoint of their causation, treatment, and prevention. METHODS: Questionnaires regarding 14 specific complications of transsphenoidal surgery were mailed to 3172 neurosurgeons. The data reported were analyzed from the 958 respondents (82%) who reported performing the operation. The neurosurgeons surveyed were asked to estimate the number of transsphenoidal operations performed, to identify any complications observed, and to estimate the percentage of operations that had resulted in any of the 14 specific complications. The 958 respondents were placed into three experience groups, based on the number of transsphenoidal operations performed. The data were analyzed by using chi 2 tests and Spearman correlation coefficients. The secondary objectives were met through a detailed review of the literature, in light of our experience. RESULTS: Of the respondents, 87.3% reported having performed < 200 operations and 9.7% reported 200 to 500 previous operations. The remaining 3% reported more than 500 previous operations. More extensive previous experience with transsphenoidal surgery was associated with a greater likelihood of having witnessed each specific complication. The mean operative mortality rate for all three groups was 0.9%. Anterior pituitary insufficiency (19.4%) and diabetes insipidus (17.8%) were complications with the highest incidence of occurrence. The overall incidence of cerebrospinal fluid fistulas was 3.9%. Other significant complications, such as carotid artery injuries, hypothalamic injuries, loss of vision, and meningitis, occurred with incidence rates between 1 and 2%. An inverse relationship was found between the experience group and the likelihood of complications, as indicated by significant negative Spearman correlation coefficients for all but 2 of the 14 complications listed in the survey (P < 0.05). Thus, increased experience with transsphenoidal surgery seems to be associated with a decreased percentage of operations resulting in complications. Some caution should be exercised in interpreting these data, because they are based on the respondents' estimates. CONCLUSION: Transsphenoidal surgery seems to be a reasonably safe procedure, with a mortality rate of less than 1%. However, a significant number of complications do occur. The incidence of these complications seems to be higher, with statistical significance, in the hands of less experienced surgeons. The learning curve seems to be relatively shallow, because a statistically significantly decreased incidence of morbidity and death could be documented after 200 and even 500 transsphenoidal operations. Better understanding of the indications for transsphenoidal surgery and improved familiarity with the regional anatomy should further lower the incidence of death and morbidity resulting from this procedure in the hands of all neurosurgeons.

Adenoma↗
PubMed1997

An expert-guided decision tree construction strategy: an application in knowledge discovery with medical databases.

With the steady growth in electronic patient records and clinical medical informatics systems, the data collected for routine clinical use have been accumulating at a dramatic rate. Inter-disciplinary research provides a new generation of computation tools in knowledge discovery and data management is in great demand. In this study, an expert-guided decision tree construction strategy is proposed to offer an user-oriented knowledge discovery environment. The strategy allows experts, based on their expertise and/or preference, to override inductive decision tree construction process. Moreover, by reviewing decision paths, experts could focus on subsets of data that may be clues to new findings, or simply contaminated cases.

Algorithms↗
PubMed1995

A phase II controlled study of a combination of the immune modulator, lentinan, with didanosine (ddI) in HIV patients with CD4 cells of 200-500/mm3.

This study was carried out to assess the safety and efficacy of a combination of lentinan, an immune modulator, and didanosine (ddI) in a controlled study in HIV positive patients with CD4 levels of 200-500 cells/mm3. Didanosine was administered to HIV patients at doses of 400 mg/day (po) for six weeks (bid), then 2 mg of lentinan i.v. was added per week for 24-80 weeks. A control group (20%) received ddI only. A total of 107 patients were enrolled at three sites, and 88 patients started the ddI/lentinan phase. The combination caused significant increases in CD4 levels up to 38 weeks, whereas ddI alone was significant at the 5% level at 14 weeks. Based on these data, lentinan qualifies as a participant in future multi-drug studies in HIV.

Adjuvants, Immunologic↗
PubMed1994

Quantitative carcinogenesis and dosimetry in rainbow trout for aflatoxin B1 and aflatoxicol, two aflatoxins that form the same DNA adduct.

Two exposure protocols were used to establish complete dose-response relationships for the hepatic carcinogenicity and DNA adduction in vivo of aflatoxin B1 (AFB1) and aflatoxicol (AFL) in rainbow trout. By passive egg exposure, AFL was taken up less well than AFB1, but was more efficiently sequestered into the embryo itself, to produce an embryonic DNA binding curve that was linear with carcinogen dose and with a DNA binding index three-fold greater than AFB1. Both aflatoxins produced the same phenotypic response, predominantly mixed hepatocellular/cholangiocellular carcinoma. Tumor responses as logit [incidence] vs. In [dose] were parallel-offset, non-linear responses showing a three-fold greater carcinogenic potency for AFL at all doses examined (i.e. 3 times more AFB1 than AFL required to produce an equivalent liver tumor incidence). By molecular dosimetry analysis (logit [incidence] vs. In [DNA adducts]), the two data sets were coincident, indicating that, per DNA adduct formed in vivo in total embryonic DNA, these two aflatoxins were equally efficient in tumor initiation. By dietary fry exposure, both carcinogens produced linear DNA binding dose responses in liver, but with an AFL target organ DNA binding index only 1.14 times that of AFB1 by this exposure route. The tumor dose-response curves also did not exhibit the three-fold difference shown by embryo exposure, but were closely positioned non-linear curves. Since the DNA binding indices differed by only 14%, the resulting molecular dosimetry curves for AFL and AFB1 by dietary exposure were similar to the tumor response curves. These results indicate that differing exposure routes produced differing relative carcinogenicity estimates based on doses applied, as a result of protocol-dependent differences in AFL and AFB1 pharmacokinetic behaviors, but that potency comparisons based on molecular dose received were similar for the two protocols. By comparison with standard DNA adducts produced in vitro using the dimethyloxirane-produced 8,9-epoxides of AFB1 and AFL, we conclude that > 99% of AFL-DNA adducts produced in vivo were identical to those produced by AFB1. Thus similar molecular dosimetry responses should be expected under all exposure protocols in which the two parent carcinogens do not exhibit differing toxicities to the target organ.

Aflatoxin B1↗
PubMed1992

A mother's work: two levels of feminist analysis of family-centered care.

The following case describes 5 years of a mother's care for her child with multiple chronic conditions, in the neonatal intensive care unit and at home. Because caregiving is primarily a female activity, a feminist approach is used. This mother's efforts on behalf of her son show how work within the domains of direct medical care, normal mothering care, coordination of equipment and supplies and professionals, and synthesis of meaning emanated from her definition of motherhood. The case suggests interventions in family-centered care, offers an examination of two levels of feminist analysis for their usefulness to occupational therapy, and provides an opportunity to examine the topic of motherhood within feminism.

Abnormalities, Multiple↗
PubMed1991

A comparison of the pharmacokinetic properties of streptokinase and anistreplase in acute myocardial infarction.

1. The pharmacokinetics of streptokinase (SK) and anistreplase in conventional dosage regimens of 1.5 x 10(6) i.u. of SK infused over 60 min and 30 units of anistreplase over 5 min were studied in 24 consecutive patients presenting with acute myocardial infarction, using a functional bioassay to assess concentrations. 2. The two agents were found to have similar volumes of distribution (5.68 and 5.90 l), but SK was cleared significantly more rapidly than anistreplase, resulting in a shorter terminal phase half-life (0.61 vs 1.16 h) and a shorter mean residence time (0.76 vs 1.55 h).

Aged↗
PubMed1991

Occupational science: academic innovation in the service of occupational therapy's future.

Occupational science is a new scientific discipline that is defined as the systematic study of the human as an occupational being. A doctoral program in occupational science has been established at the University of Southern California, Los Angeles. With its emphasis on the provision of a multidimensional description of the substrates, form, function, meaning, and sociocultural and historical contexts of occupation, occupational science emphasizes the ability of humans throughout the life span to actively pursue and orchestrate occupations. In this paper, occupational science is described, defined, and distinguished from other social sciences. A general systems model is presented as a heuristic to explain occupation and organize knowledge in occupational science. The development of occupational science offers several key benefits to the profession of occupational therapy, including (a) fulfillment of the demand for doctoral-level faculty members in colleges and universities; (b) the generation of needed basic science research; and (c) the justification for and potential enhancement of practice.

Education↗