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Biomedical subjects

C M Baker

Publications and source records attributed to C M Baker.

At least 19 recordsLinked to original sources
PubMed2001

Evidence of a functional alpha7-neuronal nicotinic receptor subtype located on motoneurons of the dorsal motor nucleus of the vagus.

In vitro autoradiography using 125I-alpha-bungarotoxin (alpha-BGTx) and anti-alpha7 immunohistochemistry were performed on the dorsal motor nucleus of the vagus (DMV) of sham and chronically vagotomized rats to determine whether the alpha7-nicotinic acetylcholine receptor (nAChR) is located postsynaptically on DMV neurons whose axons contribute to the vagus nerve. Intense bilateral 125I-alpha-BGTx binding and anti-alpha7 immunostaining were observed in coronal brain sections containing the DMV of sham-vagotomized animals. Unilateral cervical vagotomy resulted in ipsilateral losses of 125I-alpha-BGTx binding and anti-alpha7 immunostaining from the DMV. Simultaneous staining of rat brainstem sections with anti-alpha7 and anti-choline acetyltransferase (ChAT) antibodies (to identify cholinergic DMV neurons that project into the vagus nerve) revealed that every DMV neuron that was stained for ChAT showed alpha7-staining as well. In vagotomized animals, no ChAT-positive neurons expressing alpha7-nAChRs remained in the ipsilateral DMV. We conclude that the alpha7-nAChR subtype is located postsynaptically on DMV neurons. To test whether the alpha7-nAChR is similar to the alpha7-homomeric nAChR, experiments were performed in anesthetized rats, and compounds were microinjected into the DMV while monitoring intragastric pressure (IGP). alpha-BGTx and strychnine antagonized nicotine-induced increases in IGP; no antagonism was observed with methyllycaconitine, a compound known to block the homomeric alpha7-nAChR subtype. Recovery from alpha-BGTx-induced antagonism of the nicotine response was observed. We conclude that there is a nAChR containing the alpha7-subunit in the DMV that is different from the homomeric alpha7-nAChR subtype.

Aconitine↗
PubMed2000

Pulmonary artery trauma due to balloon dilation: recognition, avoidance and management.

OBJECTIVES: We reviewed the management and outcome of patients experiencing pulmonary artery (PA) trauma during balloon dilation (BD). BACKGROUND: Balloon dilation of the PA is important in the management of peripheral pulmonary stenosis. Successful BD requires a controlled tear of the PA; excessive tearing can produce complications ranging from pseudoaneurysms to rupture and death. The incidence and optimum management for such complications are unreported. METHODS: All records of patients who underwent branch PA dilation between June 1984 and October 1997 were reviewed; those with a significant complication were analyzed. RESULTS: Of 1,286 catheterizations in 782 patients, PA trauma (excluding isolated pulmonary edema and PA aneurysms) was identified in 29 catheterizations in 26 patients. Tears occurred distal to the area of stenosis in most cases (62%). Intensive medical management, with and without catheter directed therapy, was employed. The damaged PA was successfully coil embolized in five patients, four of whom survived; temporary balloon occlusion did not prevent death in two patients. There were six deaths from pulmonary hemorrhage. A case control analysis demonstrated that PA trauma was significantly associated with pulmonary hypertension. CONCLUSIONS: Pulmonary artery trauma associated with BD occurs mostly distal to the site of narrowing, is associated with underlying pulmonary hypertension and is frequently (5/12 or 42%) fatal in those with unconfined tears. Intensive management strategies as well as attention to distal balloon position may reduce incidence and mortality. Coil occlusion of the damaged PA appears to be a valuable strategy to prevent fatal hemorrhage.

Adolescent↗
PubMed2000

Using problem-based learning to redesign nursing administration masters programs.

Problem-based learning (PBL) is offered as an appropriate pedagogy to prepare nurse managers for the uncertainties of future administrative practice. It is a student-centered, experiential learning strategy aimed at developing clinical reasoning, structuring knowledge in real-life contexts, motivating learning, and developing self-learning skills. Health professions and business schools report positive feedback from their stakeholders after adopting this new learning paradigm.

Costs and Cost Analysis↗
PubMed2000

Hospital ownership, performance, and outcomes: assessing the state-of-the-science.

OBJECTIVE: This study 1) identified the research evidence; 2) assessed the state-of-the-science surrounding hospital ownership, performance, and outcomes in acute care hospitals in the United States; and 3) identified measurable components of hospital performance and outcomes for the organization, patient, and community. BACKGROUND: As the size of the nonprofit sector decreases and the size of the for-profit sector increases, hospital ownership warrants examination. Most research has focused on either ownership and performance or ownership and outcomes, rather than the potential interaction of all three variables. METHODS: A comprehensive, computerized search of the healthcare research literature yielded 69 data-based references published between 1985 and 1999. Coding sheets were developed to abstract the articles. Analysis involved synthesizing the research evidence for each of the three major variables and their components. RESULTS: Hospital ownership has an impact on hospital performance in relation to system operations; costs, prices, and financial management practices; and personnel issues. Organizational outcomes are similar among hospital ownership types in relation to increasing administrative costs and overall mediocre efficiency. Organizational outcomes differ among hospital ownership types in relation to nursing staff mix and professional satisfaction. The association of hospital ownership with patient outcomes varies depending on the dimension measured. The evidence is mixed or inconclusive regarding hospital ownership and access to care, morbidity, and mortality. The association of hospital ownership and adverse events is consistently supported. Hospital ownership status has an impact on the type and magnitude of community benefits. Differences among the three hospital ownership types are minimized in a competitive market. CONCLUSIONS: This study reinforces the position that nurse researchers need to include hospital ownership as an important structural variable in their studies of hospital-based nursing. Examining the conceptual links between ownership, performance, and outcomes requires the integration of macro-level and micro-level theory.

Community-Institutional Relations↗
PubMed2000

Chemokines and chemokine receptors in the pathogenesis of multiple sclerosis.

In recent years we have seen growing evidence for the role of chemokines in the pathogenesis of several infectious and non-infectious inflammatory CNS disease states, including Multiple Sclerosis (MS) and its animal model, experimental allergic encephalomyelitis (EAE). An increase in proinflammatory chemokines has been associated with demyelinating lesions and clinical neurological dysfunction in patients with MS; these chemokines could be potential targets for MS therapy. Besides a clearly defined role in mediating leukocyte migration, these and other chemokines may act as immunoregulatory molecules in the driving to Th1/Th2 responses, switch of cytokine profiles, and the induction of tolerance. Since chemokine receptors have now been identified on macrophages, microglia, astrocytes, and endothelial cells as well as neurons in the CNS, chemokine/receptor interactions may mediate functional responses in a variety of CNS cell types during the course of inflammatory disease states. Therefore, clarification of the roles of chemokines and their receptors in the pathogenesis of EAE and MS will be useful in establishing immunotherapeutic strategies for these neurological autoimmune disorders.

Chemokines↗
PubMed1999

Left superior vena cava connection to unroofed coronary sinus associated with positional cyanosis: successful transcatheter treatment using Gianturco-Grifka vascular occlusion device.

A persistent left superior vena cava connection to an unroofed coronary sinus is a rare cardiac anomaly that is associated with a variable degree of cyanosis. We report an infant with this condition and the unusual feature of cyanosis dependent on head position. When the patient's head was rotated to the left, he developed severe stenosis of the left internal jugular vein, enlarged cervical collateral veins that connected to the right superior vena cava and had an oxygen saturation 95%. When the patient's head was rotated to the right, the left internal jugular vein was widely patent and systemic oxygen saturation decreased to 87%. There was no right ventricular volume overload. Temporary occlusion of the left superior vena cava documented tolerable proximal venous pressure. Cyanosis was relieved by transcatheter closure of the left superior vena cava with a Gianturco-Grifka vascular occlusion device. Cathet. Cardiovasc. Intervent. 48:369-373, 1999.

Coronary Circulation↗
PubMed1999

Hospital consolidation. Applying stakeholder analysis to merger life-cycle.

Nearly three of every five hospitals in the United States have been involved in some form of consolidation during the past 5 years. Within this turbulent hospital merger environment, nurse executives are confronted with organizational, professional, and personal decisions. Stakeholder analysis is offered as one strategy to facilitate effectiveness throughout the hospitals' merger life-cycle.

Decision Making, Organizational↗
PubMed1996

Quality assurance procedure on a Huestis Styro-former--stay on the cutting edge.

A review of variations in block positions on port film vs. simulator film at The Nashua Regional Cancer Center, Nashua, NH, prompted the development of a method of measuring the accuracy of hot wire cut molds vs. a "test" film. The procedure is done at a minimum of once a year, or when accuracy of the block cuts are suspect. This simple test insures a high degree of confidence that the resulting cut molds are appropriate for the clinical situation and the need to recut blocks as a result of an out-of-tolerance Huestis Styro-former is kept to a minimum.

Quality Control↗
PubMed1992

Genetic variation in the African rodent subfamily Otomyinae (Muridae). II. Chromosomal changes in some populations of Otomys irroratus.

Chromosome-banding studies have been carried out on 31 specimens of Otomys irroratus from six localities. Light-microscope preparations of chromosomes were obtained from cultures of fibroblasts, spleen lymphocytes, peripheral blood lymphocytes, and directly from bone marrow. Karyotypic variability, both numerical and morphological, was detected in three populations. Diploid numbers ranged from 2n = 23 to 2n = 32. Intrapopulation differences were chiefly caused by variation in the number of copies in two pairs of small, biarmed, partly heterochromatic autosomes suggestive of B chromosomes. A major morphological variation in the karyotypes involved the presence of seven pairs of biarmed autosomes with totally heterochromatic short arms in the populations distributed to the west of 26 degrees 57' E. To the east of this longitude, populations of this species exhibited mostly acrocentric autosomes. G-banding patterns of these karyotypes and those of a karyotype from a previous study (Robinson and Elder, 1987) were compared. A chromosome originating from a tandem fusion, possibly leading to partial reproductive isolation, was found in one population. Possible implications of these results for mechanisms of speciation are discussed.

Animals↗
PubMed1989

Interinstitutional collaboration for nursing excellence: Part 1, Creating the partnership.

A partnership between two unrelated public institutions was formed to enhance the quality of clinical learning for students and staff, promote exemplary care to patients, and foster expansion of nursing research. The critical nucleus of the partnership is the unit-based clinical nurse specialist who performs the multiple functions of professional nursing: practice, education, and research. This two-part series describes the collaboration effort. Part 1 focuses on the organizational structure created for the partnership, and part 2 reports the findings of a 15-week pilot study conducted to test the model.

Education, Nursing↗
PubMed1989

Interinstitutional collaboration for nursing excellence: Part 2. Testing the model.

Two unrelated public institutions formed a partnership to foster excellence in professional nursing. The organizational structure was described in Part 1 (February 1989). This second article reports a 15-week pilot study conducted on seven hospital units to determine the degree to which the clinical nurse specialist can merge the multiple functions of professional nursing: practice, education, and research.

Education, Nursing↗
PubMed1986

"Leucine aminopeptidase" (neutral arylamidase) in sheep sera: improved resolution with gradient gel electrophoresis.

Electrophoretic resolution of the heterogeneity of sheep serum "leucine aminopeptidase" is greatly improved by the use of gradients of acrylamide polymer, together with enzyme localisation involving L-alanyl beta-naphthylamide and cobaltous ion. The improved resolution contradicts an earlier claim of the existence of only two patterns of individual variation in the heterogeneity of sheep serum "leucine aminopeptidase", with one pattern completely dominant to the other. While the sheep enzyme is unusual among mammalian serum "leucine aminopeptidases" in its complex heterogeneity, it does conform to the typical mammalian pattern of codominant individual variation. The complexity of sheep serum "leucine aminopeptidase" is useful in the study of sheep evolution.

Animals↗