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Biomedical subjects

D Carter

Publications and source records attributed to D Carter.

At least 253 records · Page 14Linked to original sources
PubMed1966

The role of the microbial flora in uremia. II. Uremic colitis, cardiovascular lesions, and biochemical observations.

Uremic colitis of varying severity occurred in the majority of conventionalized rats dying after removal of both kidneys, but was not found in uremic conventionalized and germfree rats sacrificed preterminally, or in germfree and limited-flora rats dying from uremia, or in any of the controls. The lesions were restricted to the cecum and their incidence and severity paralleled a shorter duration of survival. Cardiovascular damage including focal myocardial necrosis and calcification and patchy aortic and coronary calcification were observed in uremic rats regardless of their microbial status. These lesions had a higher incidence, developed more rapidly, and were more severe in the germfree and limited-flora rats than in the conventionalized animals. The presence or severity of the lesions, however, did not correlate with survival time of rats dying from uremia or with total plasma calcium and inorganic phosphorus levels of individual animals. Generalized necrotizing arteritis was not observed. Wound healing was poor in all uremic rats regardless of microbial status. Focal infection was noted in a few conventionalized rats dying from uremia, did not correlate with survival time, and was absent in all other groups. Comparison of biochemical findings between uremic germfree and conventionalized rats show a higher blood urea nitrogen and elevated plasma indoxyl sulfate in the presence of a microbial flora and a greater amount of plasma inorganic phosphorus in its absence. Uremia resulted in a decrease in hematocrit and increase in plasma and muscle potassium that were similar for germfree and conventionalized rats. Plasma and muscle sodium, total plasma calcium, glucose, and total protein were essentially unchanged by microbial status or uremia. Because the foregoing differences in the metabolic and histopathologic changes of uremia are linked to the known difference in microbial status of the fasting bilaterally-nephrectomized rats that were studied, they are a tangible indication of ways by which the indigenous microbial flora and its composition may affect the course of acute uremia.

Animals↗
PubMedDate not supplied

Objectives to direct the training of emergency medicine residents in off-service rotations: plastic surgery.

This is the fourth article in a continuing series on objectives for emergency medicine training; plastic surgery objectives will be presented. Plastic surgery topics overlap many in emergency medicine. Specific behaviorally based objectives for mastery of skills in plastic surgery are outlined. Specific references are provided for additional information and reinforcement in skill mastery. The basic concepts of plastic surgery are probably best learned by observation and supervised performance. Specific objectives provide guidance and direction for the didactic as well as the supervised experiences in skill mastery. These objectives provide a structure for systematically learning and mastering the content presented on a plastic surgical rotation or experience in emergency medicine training.

Education↗
PubMedDate not supplied

Objectives to direct the training of emergency medicine residents on off-service rotations: hand surgery.

This is the fifth article in a continuing series on objectives to direct the training of emergency medicine residents. The emergency physician frequently must deal with hand injuries. Often these may appear innocuous; recognition of these injuries requires certain technical skills and a working knowledge of these entities. Specific objectives presented provide guidance for the didactic content as well as skill mastery for the resident experience.

Emergency Medicine↗
PubMedDate not supplied

Expression of CSF-I and CSF-I receptor by normal lactating mammary epithelial cells.

OBJECTIVE: Previous studies suggested a potential role for macrophage colony stimulating factor (CSF-1) in lactogenic differentiation of the breast. The aim of this study was to define the regulation of CSF-1 and its receptor (CSF-1R, the product of c-fms proto-oncogene) by lactogenic hormones in the breast in vivo during pregnancy and lactation and in vitro in organ culture and mammary epithelial cell lines. METHODS: Immunohistochemical staining assays for the expression of CSF-1 and CSF-1R antigens were performed on sections of breast biopsies from nonpregnant (n = 10), prepartum (n = 4), and postpartum lactating patients (n = 7) and on sections of human mammary glands cultured in the presence of the lactogenic hormones insulin, prolactin, and glucocorticoids. Northern blot analyses were used to study the regulation of CSF-1 and CSF-1R by these same lactogenic hormones in normal and neoplastic mammary epithelial cell lines in cell culture. RESULTS: Normal, nonlactating mammary epithelium did not express CSF-1R and synthesized only low levels of CSF-1. During lactation, significant levels of both proteins could be observed in the epithelial cells that line actively lactating ducts and alveoli. Very similar increases in epithelial cell expression of CSF-1 and CSF-1R were observed in organ cultures of normal mammary gland biopsies exposed to prolactin, insulin, and glucocorticoids. Colony stimulating factor mRNA levels were increased by prolactin and/or insulin in a normal mammary epithelial cell line, while glucocorticoids had no apparent effect on CSF-1 mRNA levels. In contrast, we found that the levels of CSF-1R transcript are regulated primarily by glucocorticoids in breast carcinoma cells, while prolactin merely modulates the glucocorticoid effect. CONCLUSION: The observed increases in the expression of CSF-1 and its receptor during lactogenesis and the regulation of CSF-1/CSF-1R by lactogenic hormones suggests that this cytokine/receptor pair might play a regulatory role in the cellular events leading to the lactogenic differentiation of mammary epithelial cells.

Animals↗
PubMedDate not supplied

Perceptions of academic vulnerability associated with personal illness: a study of 1,027 students at nine medical schools. Collaborative Research Group on Medical Student Health.

About one quarter of the more than 69,000 medical students in this country suffer symptoms of mental illness, including 7% to 18% with substance use disorders. Subjective distress and physical health needs of medical students are also common and have been linked to training stresses. This first large-scale study of medical student health care examined students' physical and mental health concerns and their perceptions of academic vulnerability associated with personal illness. A 7-page, confidential written survey was given to 1,964 students at nine US medical schools in 1996 and 1997. A total of 1,027 students participated (52% response rate). Nearly all (90%) reported needing care for various health concerns, including 47% having at least one mental health or substance-related health issue. A majority of students expressed a preference for health care outside their training institution, largely due to confidentiality concerns, and 90% preferred health insurance allowing off-site care. Students expressed varying levels of concern about academic jeopardy in association with personal illness, with physical health problems such as arthritis causing the least concern and alcohol and drug abuse triggering the most concern. Consistent differences were detected in these views based on respondent's gender, training level, and institution. Most medical students perceive the need for personal health care. Nevertheless, fear of academic reprisal may prevent medical students from seeking necessary care for their health problems during training. This phenomenon may be linked in important but poorly recognized ways to emerging illness and to impairment among medical students and physicians. Women, minority, and clinical students appear more sensitive to the connection between health and academic vulnerability. Constructive implications for medical school curricula, policies, and health care services are discussed.

Adult↗
PubMedDate not supplied

Biomechanical comparison of conventional open reduction and internal fixation versus calcium phosphate cement fixation of a central depressed tibial plateau fracture.

OBJECTIVE: To evaluate the effect of calcium phosphate bone cement on stability and strength of the fracture repair in a central depressed tibial plateau fracture cadaveric model. DESIGN: Paired human cadaveric tibial specimens. SETTING: Biomechanics laboratory. PATIENTS: Uniform pure depression fractures of lateral tibial plateau were created in twenty human cadaveric tibial specimens. INTERVENTION: The first part of the study used thirteen pairs of tibiae in two groups: a control group receiving the conventional treatment of morselized bone graft and two cancellous screws and an experimental group receiving calcium phosphate bone cement only. The second part of the study used seven pairs of tibiae in two experimental groups: one receiving calcium phosphate bone cement with a more extensive void preparation and the other group receiving calcium phosphate bone cement with a more extensive void preparation and two screws. MAIN OUTCOME MEASUREMENTS: Each tibia was loaded on a Material Testing Systems machine from twenty newtons to 250 newtons for 10,000 cycles to simulate immediate postoperative load transmission to the tibial plateau. Specimens were then loaded to failure to determine the ultimate strength of the reconstruction. Displacement of the articular fragment and stiffness at each cycle were measured during dynamic loading. Peak load, deformation at peak load, and resistance to depression were measured during the load to failure. RESULTS: The treatment of depressed tibia plateau fractures with a calcium phosphate cement provides equivalent or better stability than conventional open reduction and internal fixation in pure depression tibial plateau fractures. If the fracture void is prepared by eliminating the cancellous bone under the subchondral plate, the results are further improved. CONCLUSIONS: This study suggests that the non-weight-bearing postoperative period may be significantly reduced without clinically significant articular collapse.

Absorptiometry, Photon↗
PubMedDate not supplied

Detection of mammaglobin in the sera of patients with breast cancer.

Current procedures for the diagnosis of breast cancer are cumbersome and invasive, making detection of this disease difficult. A rapid screening test for early detection of breast cancer would allow for better management of this deadly disease. In this report, we show that, with the exception of the skin, mammaglobin mRNA is specifically expressed in mammary tissue and commonly overexpressed in breast cancer. Mammaglobin is not expressed in other types of cancer including colon, lung, ovarian, and prostate cancer. Breast-specific expression of mammaglobin protein was shown using immunohistochemical methods. Mammaglobin is secreted from both established breast cancer cell lines and primary breast carcinoma cells cultured in vitro. Using a monoclonal antibody-based assay for monitoring the presence of mammaglobin in serum, elevated levels of mammaglobin were detected in sera of patients with breast cancer, but not in healthy women. Thus, mammaglobin, which is overexpressed and secreted from breast carcinoma cells, is detectable in sera of patients with breast cancer and may provide a rapid screening test for the diagnosis and management of breast cancer.

Adult↗
PubMedDate not supplied

Oncogene expression in vivo by ovarian adenocarcinomas and mixed-mullerian tumors.

Six-micron paraffin sections of paraformaldehyde-fixed specimens of 24 ovarian benign and neoplastic specimens were assayed for tumor cell-specific oncogene expression by a sensitive, quantitative in situ hybridization technique with probes for 17 oncogenes, beta-actin, and E. coli beta-lactamase. In the benign, borderline, and invasive adenocarcinomas, multiple oncogenes, including neu, fes, fms, Ha-ras, trk, c-myc, fos, and PDGF-A chains, were expressed at significant levels relative to a housekeeping gene (beta-actin). In the mixed-Mullerian tumors, a rather different pattern of oncogene expression was observed, characterized primarily by expression of sis (PDGF-B chain). For the adenocarcinomas, statistical analysis demonstrated that expression of several genes (fms, neu, PDGF-A) was closely linked to others (c-fos, c-myc) known to have important roles in the control of cell proliferation, but only one gene, fms, correlated very strongly with clinicopathologic features (high FIGO histologic grade and high FIGO clinical stage) predictive of aggressive clinical behavior and poor outcome. The authors discuss the role that tumor epithelial cell expression of the fms gene product might play in the auto- and paracrine control of growth and dissemination of ovarian adenocarcinomas.

Adenocarcinoma↗
PubMedDate not supplied

Intralaryngeal barriers to the spread of cancer.

Serial section studies were made of 412 surgical specimens removed by partial or total laryngectomy for laryngeal cancer. All sections were stained with hematoxylin and eosin. Selected sections were also stained for elastic tissue. Patterns of growth and spread of cancer within the larynx were found to be influenced by fibro-elastic ligaments and membranes which confined the tumor to anatomic compartments, and which provide margins of safety when performing partial laryngectomy.

Humans↗