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Biomedical subjects

C L Cox

Publications and source records attributed to C L Cox.

At least 55 records · Page 3Linked to original sources
PubMed1992

Synaptic potentials and effects of amino acid antagonists in the auditory cortex.

Neurons of in vitro guinea pig and rat auditory cortex receive a complex synaptic pattern of afferent information. As many as four synaptic responses to a single-stimulus pulse to the gray or white matter can occur; an early-EPSP followed, sequentially, by an early-IPSP, late-EPSP, and late-IPSP. Paired pulse stimulation and pharmacological studies show that the early-IPSP can modify information transmission that occurs by way of the early-EPSP. Each of these four synaptic responses differed in estimated reversal potential, and each was differentially sensitive to antagonism by pharmacological agents. DNQX (6,7-dinitroquinoxaline-2,3-dione), a quisqualate/kainate receptor antagonist, blocked the early-EPSP, and the late-EPSP was blocked by the NMDA receptor antagonist APV (D-2-amino-5-phosphonovalerate). The early-IPSP was blocked by the GABA-a receptor antagonist bicuculline, and the late-IPSP by the GABA-b receptor antagonists 2-OH saclofen or phaclofen. Presentation of stimulus trains, even at relatively low intensities, could produce a long-lasting APV-sensitive membrane depolarization. Also discussed is the possible role of these synaptic potentials in auditory cortical function and plasticity.

Amino Acids↗
PubMed1992

Cellular bases of neocortical activation: modulation of neural oscillations by the nucleus basalis and endogenous acetylcholine.

In the mammalian neocortex, the EEG reflects the state of behavioral arousal. The EEG undergoes a transformation, known as activation, during the transition from sleep to waking. Abundant evidence indicates the involvement of the neurotransmitter acetylcholine (ACh) in EEG activation; however, the cellular basis of this involvement remains unclear. We have used electrophysiological techniques with in vivo and in vitro preparations to demonstrate actions of endogenous ACh on neurons in auditory neocortex. In vivo stimulation of the nucleus basalis (NB), a primary source of neocortical ACh, (1) elicited EEG activation via cortical muscarinic receptors, (2) depolarized cortical neurons, and (3) produced a change in subthreshold membrane potential fluctuations from large-amplitude, slow (1-5 Hz) oscillations to low-amplitude, fast (20-40 Hz) oscillations. The NB-mediated change in pattern of membrane potential fluctuations resulted in a shift of spike discharge pattern from phasic to tonic. Stimulation of afferents in the in vitro neocortex elicited cholinergic actions on putative layer 5 pyramidal neurons. Acting via muscarinic receptors, endogenous ACh (1) reduced slow, rhythmic burst discharge and facilitated higher-frequency, single-spike discharge in burst-generating neurons, and (2) facilitated the appearance and magnitude of intrinsic membrane potential oscillations. These in vivo and in vitro observations suggest that neocortical activation results from muscarinic modulation of intrinsic neural oscillations and firing modes. Rhythmic-bursting pyramidal neurons in layer 5 may act as cortical pacemakers; if so, then modifying their discharge characteristics could alter local cortical networks. Larger, intercortical networks could also be modified, due to the widespread projections of NB neurons. Thus, NB cholinergic neurons may play a critical role in producing different states of neocortical function.

Acetylcholine↗
PubMed1991

Management of the difficult duodenal stump.

Leakage from the duodenal stump has been the most feared complication of the Billroth II reconstruction following gastric resection. The purpose of our study was to evaluate four methods of duodenal stump closure in 200 patients. One hundred and forty-seven (74%) patients had duodenal ulcers; 28 (14%) had gastric ulcers; and 25 (13%) had a variety of other inflammatory conditions. The most common indication for operation was acute hemorrhage (51%), followed by perforation (24%), intractability (15%), and obstruction (10%). Conventional duodenal closures were performed in 160 (80%) patients, Nissen's closure in 25 (13%), Bancroft's closure in 6 (3%), and tube duodenostomy in 9 (5%). Duodenal leaks occurred in four (2.5%) patients with conventional closures and in three (33%) patients with tube duodenostomies. No leaks occurred in patients with Nissen's or Bancroft's closures. The hospital mortality rate for the series was 9.5%; however, no patient who developed a duodenal leak died. We conclude that Nissen's and Bancroft's closures were safe and effective, but that tube duodenostomy did not reliably prevent uncontrolled leakage.

Adolescent↗
PubMed1991

Quality of life nursing care. An experimental trial in long-term care.

The study supports the idea that institutionalized elders' quality of life can be enhanced without increasing the cost of nursing care. By increasing resident choice and control over daily activities, well-being is enhanced despite a declining health status. Staff attitudes toward resident control and choice can be positively affected by implementing the Quality of Life Nursing Care Model.

Aged↗
PubMed1991

Fitness and absenteeism among hospital workers. Clarifying the connection.

A total of 48% of hospital workers rated poor to below average in fitness. Administrative and clericals had the lowest fitness rating, while technical and paraprofessionals were the most fit. Illness absence days ranged from 0 to 39 in a 6 month period, with professionals absent the greatest number of days. Gender, income, and ethnicity explained 50% of the variance in the fitness results. Demographic and social characteristics potentially may confound fitness program outcome, including absenteeism.

Absenteeism↗
PubMed1990

The Health Self-Determinism Index for Children.

A convenience sample of 501 children 7 to 13 years old completed the newly developed Health Self-Determinism Index for Children (HSDI-C), a measure of intrinsic motivation in health behavior. Construct validity was supported through the factorial isolation of four theory-consistent subscales, and the correlation of the total HSDI-C (r = .36, p less than or equal to .009) with a general measure of intrinsic motivation. Alpha coefficients in three separate trials ranged between .79 and .88 for the total scale, and .78 to .88, .87 to .92, .78 to .86, and .63 to .77 on the respective subscales. Test-retest reliability for the total scale was .83 at 2 weeks and .48 at 1 year. A nominated population of 21 third- through seventh-grade children known to practice positive health promotion behaviors had an HSDI-C mean score of 106.5 versus 76.5 in the general sample of children.

Adolescent↗
PubMed1990

Patient classification in home health care: are we ready?

This longitudinal descriptive study retrospectively profiled the acutely ill patient in home health care and explored the utility of using patient record data in predicting agency resource use and patient outcome. The findings suggest that those variables traditionally relied on for reimbursement qualification and as components of patient-classification schemes may not be wholly adequate to explain resource use and patient outcome in the home health setting. Professional nursing judgment of the patient's prognosis was found to be the most sensitive variable predicting outcome. Selected diagnoses and self-care capacity of the patient were the major predictors of resource use. Suggestions are offered for further studies that may move public health nursing more quickly toward the development of consistent and accurate home health care case mix measures.

Aged↗
PubMed1989

Argiotoxin-636 blocks excitatory synaptic transmission in rat hippocampal CA1 pyramidal neurons.

Argiotoxin 636, (AR636), a synaptic antagonist from orb weaver spider venom, is shown to produce reversible blockade of excitatory transmission in CA1 pyramidal neurons of the in vitro rat hippocampus. Microtopical application of AR636 (5-50 nM) resulted in a concentration-dependent suppression of the amplitude of the dendritic field EPSP recorded from stratum radiatum, and the amplitude of the population spike recorded from stratum pyramidale in response to stimulation of the Schaffer collaterals. The maximum effect of AR636 occurred at about 15-25 min. These effects were reversible after washing with toxin-free physiological solution with the rate of recovery having an inverse relationship to the concentration of AR636. In contrast to the effects observed with orthodromic stimulation, the amplitude of the antidromic spike was not affected by exposure to AR636. The temporal pattern of GABAergic paired-pulse inhibition was unaffected by exposure to AR636. Neuronal discharge elicited by pressure ejection of L-glutamate was abolished by AR636, whereas, responses to L-aspartate were not significantly affected. These data suggest that AR636 functions as a selective antagonist of glutamate-mediated synaptic transmission in rat hippocampus.

Action Potentials↗
PubMed1987

Motivation in health behavior: measurement, antecedents, and correlates.

Additional reliability, validity, and information on health behavior correlates for a recently developed measure of intrinsic motivation in health behavior are reported. A randomly selected sample of 379 elders responded to a structured interview containing the Health Self-determinism Index (HSDI) and other relevant variables. The overall reliability of the HSDI was supported with an alpha coefficient of 0.78. The multidimensionality of the instrument was reconfirmed through principal components analysis, and factor invariance across study samples was established. The total HSDI and subscale scores were associated with the practice of selected life-style behaviors. The homogeneity of the sample raises significant considerations relative to contextual item sensitivity and sample-induced response tendencies.

Aged↗
PubMed1986

The interaction model of client health behavior: application to the study of community-based elders.

The Interaction Model of Client Health Behavior (IMCHB) was used to direct a systematic and comprehensive description of community-based elders. The abstract concepts, constructs, factors, and variables described by one element of the model were able to account for 54% of the variance in elders' health status and 47% of the variance in their well-being. The model, as operationalized in this study, pointed to clear demographic, social, and health profiles that identified the elder at risk for decreased health, well-being, and self-care potential. The IMCHB would appear to be a useful framework with which to establish an empirical base on which nursing interventions could be developed.

Aged↗
PubMed1984

Empirical test of the interaction model of client health behavior.

The general concepts, variables, and relationships described by the Interaction Model of Client Health Behavior (IMCHB) were used to guide a secondary data analysis of 203 women's decisions to request an amniocentesis. Step-wise multiple regression explained 58% of the variance in these decisions by jointly examining the factors which define the client as unique in her responses to an at-risk pregnancy, as well as factors describing the client-provider interaction. The women could be correctly classified as users or nonusers of prenatal diagnosis with 87% accuracy in a discriminant analysis based on the variables derived from the conceptual model. Finally, structural equation modeling was used to estimate the causal paths described by the general model. While the relationships proposed in the model need further empirical evaluation, this first application serves to demonstrate the testability of the IMCHB and its potential to direct nursing inquiries.

Adult↗
PubMed1981

The choice.

Explore the source record for details and available documents.

Aged↗