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Biomedical subjects

C Baker

Publications and source records attributed to C Baker.

At least 19 recordsLinked to original sources
PubMed2001

Peripheral target contact regulates Ca2+ channels in the cell bodies of bullfrog sympathetic ganglion B-neurons.

Tyrosine-hydroxylase immunohistochemistry demonstrated that a single injection of 120 mg/kg 6-hydroxydopamine (6-OHDA) reversibly disconnected bullfrog sympathetic ganglia from their peripheral targets. This was correlated with a decrease in sympathetic outflow to the eyes and a reversible decrease in pupil diameter. 6-OHDA did not damage the cell bodies of ganglionic neurons. Calcium channel current in ganglionic B-neurons, (measured at -10 mV; holding potential -60 mnV; Ba2+ as charge carrier; IBa) was reduced. It reached a minimum of about 40% of control amplitude 7-14 days after 6-OHDA injection and recovered to 73% of control amplitude after 63 days. 6-OHDA induced loss and recovery of functional sympathetic innervation of peripheral target tissues, as determined by measurement of pupil diameter, occurred at a similar rate. Thus, pupil diameter attained mininum values 7-14 days after 6-OHDA treatment and recovered to 81% of control after 63 days. The properties of Ca2+ channels in sympathetic neurons are, therefore, determined by continuity of contact with peripheral target. 6-OHDA also decreased the peak amplitude and duration of the afterhyperpolarization (a.h.p) that follows the action potential (a.p.). The rate of recovery of a.h.p duration was more rapid than the rate of recovery of peak a.h.p. amplitude. This may reflect known differences in properties of two types of Ca2+-sensitive K currents. IC and IAHP, IC, which is responsible for the peak amplitude of the a.h.p has a low affinity for Ca2+, whereas IAHP, which determines a.h.p. duration, has higher Ca2+ affinity.

Action Potentials↗
PubMed2001

Bexarotene capsules and gel for previously treated patients with cutaneous T-cell lymphoma: results of the Australian patients treated on phase II trials.

Bexarotene (Targretin, LGD1069) is a novel synthetic retinoid analogue that binds selectively to retinoid X receptors. We describe eight previously treated patients who entered phase II international multicentre studies examining the role of bexarotene in cutaneous T-cell lymphoma. Patients received either the oral formulation (n = 7) or the topical gel (n = 1). Of the seven patients who received 300 mg/m2 per day capsules, five (71%) achieved a partial response, with mean time to onset of response of 27 days (range, 20-29) with responses persisting for a mean of 92 days (range, 57-115). The single patient receiving the topical preparation (stage IB) remains in partial response at 31 months. The major toxicity with oral administration was hypertriglyceridaemia requiring therapy. Bexarotene capsules and gel are active and generally well-tolerated agents in patients with cutaneous T-cell lymphoma and studies examining its role in previously untreated patients or as part of combination therapy are warranted.

Administration, Oral↗
PubMed2001

D-penicillamine in systemic sclerosis? Yes!

The use of D-penicillamine in systemic sclerosis (SSc) has been controversial. We have reviewed the major published studies on this drug in SSc with diffuse cutaneous (dc) involvement and summarized our own recent experience in dcSSc patients treated with and without D-penicillamine. We conclude that D-penicillamine favourably alters the natural history of skin involvement in dcSSc, even when used in low dose. Furthermore, recurrence of diffuse skin change after discontinuation of D-penicillamine and improvement in skin thickening after reinitiation of the drug support its effectiveness. We believe that the rheumatologic community should use D-penicillamine in patients with early dcSSc.

Antirheumatic Agents↗
PubMed2000

Sensory processing of water currents by fishes.

Water currents are extremely important in the aquatic environment and play a very significant role in the lives of fishes. Sensory processing of water currents involves a number of sensory modalities including the inner ear, vision, tactile sense and the mechanosensory lateral line. The inner ear will detect whole-body accelerations generated by changes in flow, or by turbulence, whereas visual and tactile inputs will signal translational movement with respect to an external visual or tactile reference frame. The superficial neuromasts of the mechanosensory lateral line detect flow over the surface of the body and have the appropriate anatomical distribution and physiological properties to signal the strength and the direction of flow and, hence, contribute to the detection of regional differences in flow over different parts of the body.

Animals↗
PubMed2000

Undecylenic acid inhibits morphogenesis of Candida albicans.

Resilient liners are frequently used to treat denture stomatitis, a condition often associated with Candida albicans infections. Of 10 liners tested, 2 were found to inhibit the switch from the yeast form to hyphae and a third was found to stimulate this switch. The inhibitor was determined to be undecylenic acid.

Candida albicans↗
PubMed2000

Building a vision for the future: strategic planning in a shared governance nursing organization.

Today's health care delivery environment is marked by extreme turbulence and ever-increasing complexity. Now, more than ever, an organization's strategic plan must do more than outline a business plan. Rather, the strategic plan is a fundamental tool for building and sustaining an organizational vision for the future. The strong, dynamic strategic plan (1) represents a long-range vision for improving organizational performance, (2) provides a model for planning and implementing structures and processes for the management of outcomes, (3) reflects and shapes the organizational culture and customer focus, (4) provides decision support for difficult operational choices made day to day, and (5) integrates and aligns the work of the organization. This article describes the development, implementation, and evaluation of a methodology for strategic planning within a shared governance nursing organization. Built upon the strategic plan of the hospital, the process undertaken by the nursing organization reflects the following commitments: (1) to develop a strategic plan that is meaningful and part of daily work life at all levels of the nursing organization, (2) to make the plan practical and realistic through incremental building, (3) to locate and articulate accountability for each step, and (4) to build in a process for checking progress toward goal achievement and readjusting the plan as necessary.

Decision Making, Organizational↗
PubMed1999

A phase I study of adenovirus-mediated transfer of the human cystic fibrosis transmembrane conductance regulator gene to a lung segment of individuals with cystic fibrosis.

A third-generation adenoviral vector containing recombinant human cystic fibrosis transmembrane conductance regulator (CFTR) gene was delivered by bronchoscope in escalating doses to the conducting airway of 11 volunteers with cystic fibrosis. Assessments of dose-limiting toxicity (DLT), efficiency of gene transfer, and cell-mediated and humoral immune responses to vector administration were performed. DLT, manifest by flulike symptoms and transient radiographic infiltrates, was seen at 2.1 x 10(11) total viral particles. A highly specific assay for gene transfer was developed using in situ hybridization with an oligoprobe against unique vector sequence. Detectable gene transfer was observed in harvested bronchial epithelial cells (<1%) 4 days after vector instillation, which diminished to undetectable levels by day 43. Adenovirus-specific cell-mediated T cells were induced in most subjects, although only mild increases in systemic humoral immune response were observed. These results demonstrate that gene transfer to epithelium of the lower respiratory tract can be achieved in humans with adenoviral vectors but that efficiency is low and of short duration in the native CF airway.

Adenoviridae↗
PubMed1999

Solution structure of the sodium channel inactivation gate.

The sodium channel initiates action potentials by opening in response to membrane depolarization. Fast channel inactivation, which is required for proper physiological function, is mediated by a cytoplasmic loop proposed to occlude the ion pore via a hinged lid mechanism with the triad IFM serving as a hydrophobic "latch". The NMR solution structure of the isolated inactivation gate reveals a stably folded core comprised of an alpha-helix capped by an N-terminal turn, supporting a model in which the tightly folded core containing the latch motif pivots on a more flexible hinge region to occlude the pore during inactivation. The structure, in combination with substituted cysteine mutagenesis experiments, indicates that the IFM triad and adjacent Thr are essential components of the latch and suggests differing roles for the residues of the IFMT motif in fast inactivation.

Amino Acid Sequence↗
PubMed1999

Lung-sparing surgery after penetrating trauma using tractotomy, partial lobectomy, and pneumonorrhaphy.

OBJECTIVE: To evaluate the role of lung-sparing surgical techniques in the surgical management of penetrating pulmonary injuries. DESIGN: Retrospective case series. SETTING: Academic level I trauma center. PATIENTS AND METHODS: Forty patients underwent thoracic surgery for penetrating lung injuries during a 63-month period from January 1993 to March 1997. Five (12.5%) underwent anatomical lobectomy, 3 (7.5%) pneumonorrhaphy, 9 (22.5%) stapled wedge resection, and 23 (57.5%) stapled tractotomy. In total, 34 patients (85%) were treated with stapling techniques (1 anatomical lobectomy, 1 pneumonorrhaphy, 9 stapled wedge resections, and 23 stapled tractotomies) and 35 (87.5%) underwent had lung-sparing surgery for trauma. RESULTS: Morbidity and mortality rates were 40% and 5%, respectively. Patients who underwent anatomical lobectomy required longer mechanical ventilatory support, intensive care unit stay, and hospital stay and had a higher morbidity rate compared with patients who underwent lung-sparing surgery for trauma but had central and extensive pulmonary injuries. Stapled tractotomy was efficient in controlling bleeding and bronchial leaks, but, in 3 patients, parts of the divided lung parenchyma were devascularized and had to be resected. CONCLUSIONS: Lung-sparing surgery for trauma with the use of staplers can be used in the majority of patients with penetrating pulmonary injuries requiring operation. Stapled tractotomy is a rapid and effective method for controlling hemorrhage and air leaks.

Adult↗
PubMed1999

Transforming growth factor-beta2 is elevated in skeletal muscle disorders.

The transforming growth factor betas (TGF-betas) are multifunctional growth factors that act on both fibroblasts and myosatellite cells. In rodent models of muscle diseases, high levels of TGF-beta2 are expressed by myogenic cells. We have examined whether the expression of TGF-beta2 is also elevated in diseased human muscles. The disorders examined were Duchenne muscular dystrophy, myotonic dystrophy, myotubular myopathy, spinal muscular atrophy, and amyotrophic lateral sclerosis. The levels of TGF-beta2 immunoreactivity were elevated in atrophic, necrotic, and regenerating fibers and in fibers with central nuclei or cytoplasmic masses, irrespective of whether fibrosis was present. We therefore suggest that TGF-beta2 is important for muscle repair and that the presence of a TGF-beta within a muscle only leads to fibrosis if certain other factors are present.

Amyotrophic Lateral Sclerosis↗
PubMed1999

Dynamic exercise normalizes resting blood pressure in mildly hypertensive premenopausal women.

BACKGROUND: Dynamic exercise acutely and transiently lowers resting blood pressure in hypertensive men and is termed postexercise hypotension (PEH). We examined 18 premenopausal women (7 hypertensive and 11 normotensive) to determine if PEH occurs in women and to elucidate possible hemodynamic and hormonal mechanisms. METHODS AND RESULTS: Patients wore an ambulatory blood pressure monitor throughout the day after 40 minutes of a rest sham session and 40 minutes of cycle exercise, of which 30 minutes was performed at 60% of maximal oxygen consumption. Cardiac output and total systemic vascular resistance were determined by Doppler echocardiography before and 15 minutes after sham and exercise. Catecholamines, plasma renin activity, and beta-endorphin were measured over this same period. PEH occurred only in the hypertensive women. Systolic, diastolic, and mean arterial blood pressure decreased in the hypertensive women by a mean of 9.5 +/- 2. 8 mm Hg (P <.01), 6.7 +/- 2.4 mm Hg (P <.05), and 7.7 +/- 2.4 mm Hg (P <.05), respectively, for up to 7 hours after versus before exercise, whereas blood pressure was similar in the normotensive women (P >.05). After exercise, total systemic vascular resistance was lower (P <.01), and cardiac output, catecholamines, and plasma renin activity were greater (P <.01) than before exercise in both groups of women. CONCLUSIONS: PEH was observed for up to 7 hours after exercise in mildly hypertensive women and was not explained by the hemodynamic and hormonal adjustments that occurred after exercise. The magnitude and duration of PEH may be sufficient to normalize the blood pressure of certain hypertensive women throughout most of the day.

Adult↗
PubMed1999

Effectiveness of cognitive therapy training.

Despite growing demands for effective training there remains a lack of convincing evaluations. Reviews of the training literature specify the need for multiple measures, homogeneous therapies, generalization assessments and longitudinal designs. The present analysis responds by evaluating the training of 20 mental health professionals in cognitive therapy (CT). The evaluation focussed on changes in the professionals' competence and its generalization to their patients' coping strategies (N = 20). Results indicated that a 40 day training programme led to significantly higher post-training competence scores and to improved patient coping. The implications for professional training and its evaluation are discussed.

Adult↗
PubMed1999

Evaluation of pediatric cervical spine injuries.

To compare historical features, clinical examination findings, and radiographic results among pediatric patients with cervical spine injury (CSI), a retrospective review of patients who were diagnosed with CSI was undertaken. Two main groups were identified: radiographically evident cervical spine injury (RESCI), and spinal cord injury without radiographic abnormality (SCIWORA). Demographic, historical, clinical, and radiographic information was obtained from patients' charts and analyzed to determine factors associated with CSI and to determine the efficacy of the various radiographic views. Seventy-two children, ages from 1 month to 15 years (median age, 9 yrs), were included in the study. Sports-related injuries were the most common. Forty patients had RESCI and 32 had SCIWORA. Forty-nine (80%) of all the patients had abnormal findings on neck examination, and six (16%) of the RECSI group had abnormal neurological findings. Lateral radiographs had a sensitivity for CSI of 79%; a three-view radiographic series had a sensitivity of 94%. All patients with CSI who were clinically asymptomatic had both a high-risk injury mechanism and a distracting injury. CSI should be suspected in any child with abnormal findings on neck or neurological examination. A minimum of three radiographic cervical spine views should be obtained in the evaluation of CSI in children. Even in the face of a three-view series, CSI should be suspected in patients with an abnormal neck or neurological exam, high-risk mechanism of injury, or distracting injury.

Adolescent↗
PubMed1999

Development of an activities of daily living scale to screen for dementia in an illiterate rural older population in India.

OBJECTIVE: to develop a measure of activities of daily living appropriate for use in assessing the presence of dementia in illiterate rural elderly people in India. DESIGN: identification of relevant items, pre-testing of items and refinement of administrative procedures and scoring in four successive groups of 30 subjects each, pilot testing in a group of 100 subjects comparable to those for whom the measure is intended, administration to a representative sample of 387 people aged 55 and older, and assessment of the reliability of the final measure. SETTING AND SUBJECTS: age-stratified random sample of older men and women in rural areas of Ballabgarh, Northern India. RESULTS: the original pool of 35 items covering mobility, instrumental and personal care activities was reduced to an 11-item unidimensional scale (to which an additional item on mobility was added) with internal consistency (Cronbach's alpha)=0.82, perfect inter- and intra-rater reliability, test-retest reliability (intraclass correlation)=0.82 (any disability) and 0.92 (unable to perform for 'mental' reasons). Women, older subjects, the totally illiterate and subjects with poorer cognitive function performed significantly more poorly (P < or = 0.02 for all). PRODUCT: a brief, reliable and valid activities of daily living measure, with norms, which is appropriate for use in assessing dementia in illiterate rural elderly people in India.

Activities of Daily Living↗