Search PubMed⌕ Search

Biomedical subjects

M Davis

Publications and source records attributed to M Davis.

At least 757 records · Page 42Linked to original sources
PubMedDate not supplied

The case for a student honor code and beyond.

Preparing graduates to enter practice as responsible and accountable nurses is an essential goal of nursing programs. Faculty must be deliberate in their efforts to enhance personal and professional integrity and to facilitate the development of a value system that the graduates can incorporate into their professional practices. A student honor code within a school of nursing is one strategy that faculty can use to facilitate the development of these characteristics. A variety of resources, both human and printed, are available to guide the faculty.

Civil Rights↗
PubMedDate not supplied

Chromosome translocation can occur on either side of the c-myc oncogene in Burkitt lymphoma cells.

In Burkitt lymphoma cells reciprocal chromosomal translocations are observed between the long arm of chromosome 8 (8q24) and either the long arm of chromosome 14 (14q32), the short arm of chromosome 2 (2p12) or the long arm of chromosome 22 (22q11). Gene mapping studies have shown that c-myc, the cellular homologue of the viral myc oncogene, is localized at 8q24 (ref 3-5) and that the three immunoglobulin gene loci map at the breakpoints involved in the translocation: immunoglobulin heavy-chain genes are located at 14q32 (refs 6, 7), kappa light chains at 2p12 (ref. 8) and delta light chains at, or close to, 22q11 (ref 9, 10). This correlation suggests an association of immunoglobulin gene rearrangements with the occurrence of these specific translocations. By using in situ hybridization we have examined the translocation point with respect to c-myc in two cell lines containing 2;8 translocation, and report here that the c-myc gene remains on the chromosome 8 involved in the reciprocal exchange with chromosome 2. We have also confirmed that the c-myc gene moves from the translocated chromosome 8 in a cell line having a 8;14 translocation. These results show that chromosomal breakage can occur on either side of the c-myc gene in Burkitt lymphoma cells.

Burkitt Lymphoma↗
PubMedDate not supplied

Clinical trials of a biosynthetic temporary skin replacement, Dermagraft-Transitional Covering, compared with cryopreserved human cadaver skin for temporary coverage of excised burn wounds.

Human cadaver allograft skin (HCAS) is widely used for covering excised burn wounds when limited available skin donor sites or the overall patient condition does not permit immediate grafting with autologous skin. However, recurring problems are associated with HCAS including limited supply, variable quality, ultimate immune rejection, and the potential for bacterial and viral disease transmission. These problems speak for the need for development of a dependable substitute for HCAS. We evaluated the ability of a biosynthetic analogue of human skin to temporarily close excised burn wounds in humans. Dermagraft-TC (Advanced Tissue Sciences, Inc.) (DG-TC) is composed of human neonatal fibroblasts cultured on a synthetic dressing (Biobrane; Dow Hickam, Inc.) that consists of nylon mesh fabric covered with a thin layer of silicone rubber membrane, which provides an epidermal "barrier." The material is stored frozen and thawed immediately before use. DG-TC is semitransparent, thus facilitating continuous observation of the underlying wound surface. Burn wounds in 10 patients (mean age 33.5 years, mean burn size 39.9% total body surface area) were surgically excised. Two variants of the DG-TC skin analogs were tested: a material that was cryopreserved to maintain fibroblast viability (DG-TC Red) and a material that was frozen without efforts to maintain fibroblast viability (DG-TC Blue). A control site on each patient received cryopreserved HCAS. Each study site was approximately 1% total body surface area. When clinically indicated, patients were returned to the operating room where the skin replacements were removed, the wound bed was evaluated and prepared for grafting, and the wounds were closed with meshed split-thickness autograft skin. The results showed that adherence to the wound and subsequent autograft "take" were excellent with both DG-TC variants and were at least equivalent to HCAS. No evidence of immune rejection of DG-TC was seen, whereas in four patients evidence of epidermal sloughing/rejection was noted in the HCAS control sites, which limited persistence of those grafts on the wound. Further clinical trials with this skin analogue are in progress.

Adolescent↗
PubMedDate not supplied

A multicenter clinical trial of a biosynthetic skin replacement, Dermagraft-TC, compared with cryopreserved human cadaver skin for temporary coverage of excised burn wounds.

This multicenter study compared the use of a biosynthetic human skin substitute with frozen human cadaver allograft for the temporary closure of excised burn wounds. Dermagraft-TC (Advanced Tissue Sciences, Inc.) (DG-TC) consists of a synthetic material onto which human neonatal fibroblasts are cultured. Burn wounds in 66 patients with a mean age of 36 years and a mean burn size of 44% total body surface area (28% total body surface area full-thickness) were surgically excised. Two comparable sites, each approximately 1% total body surface area in size, were randomized to receive either DG-TC or allograft. Both sites were then treated in the same manner. When clinically indicated (> 5 days after application) both skin replacements were removed, and the wound beds were evaluated and prepared for grafting. DG-TC was equivalent or superior to allograft with regard to autograft take at postautograft day 14. DG-TC was also easier to remove, had no epidermal slough, and resulted in less bleeding than did allograft while maintaining an adequate wound bed. Overall satisfaction was better with DG-TC.

Adult↗
PubMedDate not supplied

Using pavlovian higher-order conditioning paradigms to investigate the neural substrates of emotional learning and memory.

In first-order Pavlovian conditioning, learning is acquired by pairing a conditioned stimulus (CS) with an intrinsically motivating unconditioned stimulus (US; e.g., food or shock). In higher-order Pavlovian conditioning (sensory preconditioning and second-order conditioning), the CS is paired with a stimulus that has motivational value that is acquired rather than intrinsic. This review describes some of the ways higher-order conditioning paradigms can be used to elucidate substrates of learning and memory, primarily focusing on fear conditioning. First-order conditioning, second-order conditioning, and sensory preconditioning allow for the controlled demonstration of three distinct forms of memory, the neural substrates of which can thus be analyzed. Higher-order conditioning phenomena allow one to distinguish more precisely between processes involved in transmission of sensory or motor information and processes involved in the plasticity underlying learning. Finally, higher-order conditioning paradigms may also allow one to distinguish between processes involved in behavioral expression of memory retrieval versus processes involved in memory retrieval itself.

Animals↗
PubMedDate not supplied

Effects of Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis.

BACKGROUND: To determine the extent and effects of increased metabolic demand represented by Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis (CF). METHODS: The study comprised 18 stable children with CF, of whom 10 (6 male/4 female) were colonized with Pseudomonas species and 8 (4 male/4 female) were not. The groups were of similar age range and genotype. Measured resting energy expenditure (REE) was performed by open circuit indirect calorimetry and compared with predicted REE calculated from standard equations. Body composition was determined by dual-energy x-ray absorptiometry, including lean body mass (LBM), fat mass (FM), bone mineral density (BMD), and anterior-posterior spine density (APS); these were compared using z-scores. Routine pulmonary function testing assessed forced vital capacity, forced expiratory volume in 1 second (FEV1), and forced expiratory flow over middle half of vital capacity (FEF25% to 75%); these were compared as percent predicted. RESULTS: As expected, results of pulmonary function testing showed significant deterioration among the children colonized with Pseudomonas species when compared with the children who were not, while standard anthropometry showed no differences in weight, height, or weight-for-height percentile and respective z-scores. Although a trend of lower LBM was noted among the children colonized with Pseudomonas species, no significant differences were found between these children and children who were not colonized with Pseudomonas species when z-scores for LBM, FM, BMD, or APS were compared during body composition analysis. In addition, neither REE as kilocalories per day (kcal/d) nor REE expressed as a percent predicted by standard equations discriminated between subgroups of children colonized with Pseudomonas species and children who were not. However, metabolic demand, expressed as resting energy expenditure in kilocalories per kilogram (kcal/kg) of LBM (REE/LBM), revealed significant differences between children colonized with Pseudomonas species and children who were not (75.4+/-4.4 vs 58.6+/-2.9 kcal/kg, p < .05). CONCLUSIONS: The effect of Pseudomonas colonization on metabolic demand in children with CF can be accurately assessed by expressing resting energy expenditure as kilocalorie per kilogram of LBM, the active metabolic component of the body. The 50% increase in REE/LBM seen in the children colonized with Pseudomonas species represents the metabolic demand from the inflammatory burden and work of breathing resulting from the effects of the Pseudomonas colonization. The trend of a lower LBM in the children colonized with Pseudomonas species makes this finding even more dramatic.

Absorptiometry, Photon↗
PubMedDate not supplied

Hydrocodone for cough in advanced cancer.

Cough is a common symptom in advanced cancer. Hydrocodone is the antitussive of choice in our palliative medicine inpatient unit. We reviewed the pharmacy records for the use of hydrocodone for all cancer admissions to our unit from May 1996 to December 1998. Median treatment duration with hydrocodone was three days (range 1-18). Median maximum daily dose was 15 mg (range 5-100), and median total dose during the hospital stay was 32 mg (range 5-455). Lung cancer as a primary cancer site was strongly related to the use of hydrocodone. The highest median duration of treatment (five days) was for esophageal cancer and the highest median maximum daily dose (35 mg) and total dose (75 mg) were for treating kidney cancer. This retrospective review provides information regarding the use of hydrocodone on the palliative medicine unit of the Cleveland Clinic Foundation. Controlled trials are needed to evaluate the efficacy and safety of hydrocodone for cough in advanced cancer.

Aged↗
PubMedDate not supplied

Methylphenidate for depression in hospice practice: a case series.

Psychostimulants such as methylphenidate have been used for depression in cancer patients. We report the successful use of methylphenidate to treat depression in 10 consecutive patients with advanced cancer. A rapid onset of effect was noted. Appetite, concentration, fatigue, and sedation also improved in some persons. No severe side effects were noted.

Aged↗
PubMedDate not supplied

The safety of discontinuation of maintenance therapy for cytomegalovirus (CMV) retinitis and incidence of immune recovery uveitis following potent antiretroviral therapy.

BACKGROUND: Reconstitution of immune function during potent antiretroviral therapy can prompt discontinuation of maintenance cytomegalovirus (CMV) therapy but has also been associated with sight-threatening inflammatory conditions including immune recovery uveitis (IRU). METHOD: Patients with inactive CMV retinitis and a CD4+ cell count above 100/mm3, receiving CMV therapy and stable combination antiretroviral therapy, were assigned to one of two groups based on willingness to discontinue CMV therapy. RESULTS: Thirty-eight participants were enrolled: 28 discontinued anti-CMV therapy (Group 1) and 10 continued CMV treatment (Group 2). Median on-study follow-up was 16 months. One Group 1 participant who experienced an increase in plasma HIV viral load and a decline in CD4+ cell count developed confirmed progression of CMV retinitis. Progression or reactivation CMV retinitis was not observed among Group 2. IRU was present at study entry in 3 participants. Six participants in Group 1 and 3 participants in Group 2 developed IRU on-study. CMV viremia was not detected in any participants, and urinary shedding of CMV was intermittent. CONCLUSION: Recurrence of CMV retinitis following discontinuation of anti-CMV therapy among patients with antiretroviral-induced increases in CD4+ cell count was rare. However, IRU was common in both those who maintained and discontinued anti-CMV therapy.

Adult↗
PubMedDate not supplied

Prescription drug coverage, utilization, and spending among Medicare beneficiaries.

Outpatient prescription drugs are not a covered benefit under Medicare. There have been proposals in the past to expand Medicare benefits to include drug coverage, and current discussions dealing with "modernizing" the Medicare benefit package have raised the issue again. Using data from the 1995 Medicare Current Beneficiary Survey (MCBS), we describe the sources and extent of drug coverage among Medicare beneficiaries. The data show that 65 percent of Medicare beneficiaries have some level of drug coverage--a figure much higher than previous published numbers--and that 95 percent of Medicare health maintenance organization (HMO) enrollees have drug coverage. The data provide a baseline to observe future changes in the level of coverage, particularly among Medicare managed care plans.

Aged↗
PubMedDate not supplied

One peer review organization's experience in developing hospital peer groups.

The Health Care Quality Improvement Initiative is moving Medicare's quality improvement activities from review and action on individual cases to the analysis of patterns of care. A primary source for pattern analysis is the mortality data presented in the Medicare Hospital Information release. One of the requirements set forth by the Health Care Financing Administration is that peer review organizations classify hospitals into peer groups in order to compare mortality rates within and among groups. It is hoped that this type of analysis will lead to a better understanding of the relationship between process and outcome for a variety of medical conditions. This report describes the experience of one peer review organization in establishing hospital peer groups.

Centers for Medicare and Medicaid Services, U.S.↗
PubMedDate not supplied

Apurinic/apyrimidinic endonuclease expression in pediatric yolk sac tumors.

BACKGROUND: The enzyme apurinic/apyriminidic endonuclease/redox factor 1 (Ape1/ref1), a key protein in the base excision repair pathway, displays repair and redox activity. We examined the role of Ape1/ref1 and a protein it regulates, hypoxia inducible factor 1 alpha (HIF-1 alpha) in pediatric yolk sac tumors. PATIENTS AND METHODS: Using an immunohistochemical evaluation, 16 pediatric yolk sac tumors were evaluated for Ape1/ref1 and HIF-1 alpha expression. Samples were obtained from archival tissue. RESULTS: We demonstrated high levels of expression of Ape1/ref1 in 14/16 of the tumors. This expression was limited to the nucleus of the viable portion of each tumor. High levels of HIF-1 alpha expression was noted in half of the same tumors and localized to both the nucleus and cytoplasm of the viable tumor. CONCLUSIONS: The high levels of expression of Ape1/ref1 in this group of chemosensitive tumors may be related to the subcellular location or redox regulatory activity of one of the other factors controlled by Ape1/ref1.

Carbon-Oxygen Lyases↗