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Biomedical subjects

D Ragsdale

Publications and source records attributed to D Ragsdale.

15 recordsLinked to original sources
PubMed2007

Reduced GABAB receptor subunit expression and paired-pulse depression in a genetic model of absence seizures.

Neocortical networks play a major role in the genesis of generalized spike-and-wave (SW) discharges associated with absence seizures in humans and in animal models, including genetically predisposed WAG/Rij rats. Here, we tested the hypothesis that alterations in GABA(B) receptors contribute to neocortical hyperexcitability in these animals. By using Real-Time PCR we found that mRNA levels for most GABA(B(1)) subunits are diminished in epileptic WAG/Rij neocortex as compared with age-matched non-epileptic controls (NEC), whereas GABA(B(2)) mRNA is unchanged. Next, we investigated the cellular distribution of GABA(B(1)) and GABA(B(2)) subunits by confocal microscopy and discovered that GABA(B(1)) subunits fail to localize in the distal dendrites of WAG/Rij neocortical pyramidal cells. Intracellular recordings from neocortical cells in an in vitro slice preparation demonstrated reduced paired-pulse depression of pharmacologically isolated excitatory and inhibitory responses in epileptic WAG/Rij rats as compared with NECs; moreover, paired-pulse depression in NEC slices was diminished by a GABA(B) receptor antagonist to a greater extent than in WAG/Rij rats further suggesting GABA(B) receptor dysfunction. In conclusion, our data identify changes in GABA(B) receptor subunit expression and distribution along with decreased paired-pulse depression in epileptic WAG/Rij rat neocortex. We propose that these alterations may contribute to neocortical hyperexcitability and thus to SW generation in absence epilepsy.

Animals↗
PubMed1998

Molecular determinants of Na+ channel function in the extracellular domain of the beta1 subunit.

The rat brain voltage-gated Na+ channel is composed of three glycoprotein subunits: the pore-forming alpha subunit and two auxiliary subunits, beta1 and beta2, which contain immunoglobulin (Ig)-like folds in their extracellular domains. When expressed in Xenopus oocytes, beta1 modulates the gating properties of the channel-forming type IIA alpha subunit, resulting in an acceleration of inactivation. We have used a combination of deletion, alanine-scanning, site-directed, and chimeric mutagenesis strategies to examine the importance of different structural features of the beta1 subunit in the modulation of alphaIIA function, with an emphasis on the extracellular domain. Deletion analysis revealed that the extracellular domain is required for function, but the intracellular domain is not. The mutation of four putative sites of N-linked glycosylation showed that they are not required for beta1 function. Mutations of hydrophobic residues in the core beta sheets of the Ig fold disrupted beta1 function, whereas substitution of amino acid residues in connecting segments had no effect. Mutations of acidic residues in the A/A' strand of the Ig fold reduced the effectiveness of the beta1 subunit in modulating the rate of inactivation but did not significantly affect the association of the mutant beta1 subunit with the alphaIIA subunit or its effect on recovery from inactivation. Our data suggest that the Ig fold of the beta1 extracellular domain serves as a scaffold that presents the charged residues of the A/A' strands for interaction with the pore-forming alpha subunit.

Amino Acid Sequence↗
PubMed1993

Expression of neurotransmitter receptors by mRNAs from neurons developing in vitro: a Xenopus oocyte expression study.

Poly(A)+ mRNA was extracted from cultures of neurons isolated from mouse embryonic day 14 cerebral cortex and injected into Xenopus oocytes. This led to the expression of receptors for gamma-aminobutyric acid (GABA), glycine, acetylcholine, serotonin, glutamate, kainate, N-methyl-D-aspartate, and quisqualate. Northern blot analysis of poly(A)+ mRNA from the cultured neurons with a GluR1 cDNA probe revealed the presence of three hybridization bands with estimated mRNA sizes of 5.1, 4.0, and 3.1 kb, respectively. The development of mRNAs coding for neurotransmitter receptors was investigated by isolating mRNA from neurons cultured for 2, 8, and 14 days in vitro and injecting it into Xenopus oocytes. The amplitude of membrane currents elicited by the transmitters gave a measure of the relative amounts of the different mRNAs. The size of the responses to kainate, aspartate (together with glycine), glutamate, acetylcholine, GABA, serotonin, and glycine increased with the time of culture in vitro. However, in contrast to all other agonist-induced currents, the current induced by glycine failed to increase further from 8 to 14 days in culture. It is concluded that the time course of receptor development in cortical neurons in vitro is similar to the development in vivo.

Animals↗
PubMed1992

Quality of life of hospitalized persons with AIDS.

This study explores quality of life from the viewpoint of Persons with AIDS (PWAs) who were interviewed during periods of hospitalization. Quality of life was viewed as the patients' perception of the relative effectiveness of a chosen or ascribed management style in solving the practical problems associated with being ill. Six management styles used by the respondents to improve their quality of life were identified. Results of this study suggest that nurses can improve PWAs' quality of life by supporting their respective management styles.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Absentee patterns among OR staff. Identifying aspects of the problem.

Absenteeism continues to be a great concern to hospital administrators. Nursing personnel should have a clear idea of acceptable attendance parameters based on written policies that are routinely administered. Efforts are now directed toward exploring strategies that reward personnel for good attendance records. Early development of professional attitudes related to absenteeism should continue to be supported and fostered. Implications from this preliminary study indicate that it may be more cost-effective to hire RNs than STs to work in ORs.

Absenteeism↗
PubMed1989

The significant other's role in improving quality of life in persons with AIDS dementia complex.

This article contains a description of how social support systems criteria can be used by nurses as a framework to include significant others in the care of their loved ones with AIDS. Nursing care parameters are identified to facilitate mutual planning among persons with AIDS dementia complex, their significant others and nurses throughout disease progression. Incorporation of the nursing intervention protocols will improve quality of life by preparing for possible alterations in mental status should dementia occur. A case study is presented to illustrate use of the intervention protocol.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Inhibition of rat brain glutamate receptors by philanthotoxin.

The actions of philanthotoxin (PhTX) were studied on the function of glutamate receptors expressed in Xenopus oocytes injected with rat brain mRNA and on binding of radioligands to rat brain glutamate receptors. PhTX reversibly inhibited the oocyte responses to quisqualate, N-methyl-D-aspartate (NMDA) and kainate in a dose-dependent manner. The NMDA receptor was the most sensitive to PhTX action (10-fold more than the kainate receptor) and the least sensitive was the smooth current component of the quisqualate response. Recovery from PhTX block differed among the three amino acids. NMDA responses recovered completely within a few minutes whereas responses to kainate and quisqualate recovered more slowly. PhTX had no effect on equilibrium binding of [3H]glutamate to rat brain cortical membranes studied in buffer treated to eliminate microorganisms. Based on the drug specificity of this [3H]glutamate binding, it is suggested to be mostly to the NMDA receptor. Low concentrations of PhTX (1-10 microM) potentiated binding of [3H] MK-801, a specific noncompetitive inhibitor of the NMDA receptor. However, higher PhTX concentrations inhibited this binding with an IC50 of 20 microM, similar to its inhibition of the oocyte-expressed NMDA receptor. Inhibition of [3H]MK-801 binding by PhTX was noncompetitive. It is suggested that PhTX, like the more potent MK-801, binds to an allosteric site on the NMDA receptor and inhibits its function but its binding site is not identical with the MK-801 binding site.

Animals↗
PubMedDate not supplied

Using social support theory to care for CVA patients.

The purpose of this article is to describe how social support theory was used to guide the nursing care of patients admitted to a rehabilitation unit in a large teaching hospital in a metropolitan medical center. Criteria from Caplan's Social Support Theory (Caplan & Killilea, 1976) were used to outline a plan that included input from significant others to create a plan for their loved ones who were recovering from left-side CVAs. All nursing care was based on the cognitive and intellectual abilities of the patients. Two case studies are presented to illustrate the use of these nursing protocols.

Aged↗
PubMedDate not supplied

Health locus of control among HIV-positive indigent women.

The authors explored the multidimensional construct of health locus of control among 14 indigent HIV-positive women who attended one of two southwestern city health clinics. An exploratory survey design was used to compare the mean responses of the subjects on the Multidimensional Health Locus of Control (MHLC) Scales with established normative data. The women believed they had control over their health, yet felt powerful others and chance determine their health outcomes. These findings are drawn from high scores on both the Internal and External MHLC Scales. Findings imply that these women may not view themselves as having any control in the dichotomous world of acute and chronic illness. Authors recommend that nurses should encourage their patients to participate in the management of their health care.

Acute Disease↗
PubMedDate not supplied

Work-related activities to improve quality of life in HIV disease.

The authors conducted an ethnographic analysis of various ways that persons with AIDS (PWAs) manage their illness in order to improve quality of life. According to Anselm Strauss (1975), illness management involves "work": The activities associated with work change as disease-related symptomatology presents different responses. Strauss' concept of work served as the theoretical orientation for this study. The researchers interviewed the respondents (N = 19) while they were hospitalized for problems related to their diagnosis of AIDS. Analysis was guided by grounded theory. Several categories of management activities emerged. The participants perceived all work-related activities as very important to life in the hospital. They perceived nurses as confederates who were involved in many of the work activities. Quality of life was enhanced when PWAs were able to conduct activities they felt were important and when the healthcare team supported their work.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Quality of life as a function of HIV classification.

The purpose of this research was to identify variables related to life quality for persons with Human Immunodeficiency Virus Infection and to ascertain if life quality differs according to the classifications of a positive serologic test for HIV antibodies (HIV+), AIDS-related complex (ARC), and Acquired Immunodeficiency Syndrome (AIDS). A convenience sampling technique was used to obtain subjects from AIDS support groups and affiliated agencies in a major southwest urban area. Ninety-five HIV-infected subjects completed a demographic data sheet, the Sickness Impact Profile (SIP), and the Symptom Distress Scale (SDS). The majority of subjects (59%) listed AIDS as their category of diagnosis, 25% were HIV+ only and 16% identified ARC as their disease classification. Subjects had SIP and SDS scores which indicated HIV-infection significantly affected their quality of life. Multivariate results indicated that quality of life indicators varied as a function of HIV classification. HIV-infection had the greatest disruption in psychosocial aspects of life. The impact of HIV-infection (both physical and psychosocial) was greatest in subjects with ARC and least among subjects who were HIV+ only.

AIDS-Related Complex↗
PubMedDate not supplied

Nutritional program for heart transplantation.

Methodist Hospital has completed 52 heart transplants during its 4 1/2-year history. Dietary restrictions for patients have been deemed necessary to offset the side effects from medication. The purpose of this article is to provide information regarding the nutritional program for heart transplant recipients. Evaluation of the dietary program, changes made, and problems encountered are discussed. The first 10 patients were instructed on a type IIA hyperlipoproteinemia (300 mg cholesterol), no concentrated sweets, and 2 to 4 gm sodium-restriction diet with no fresh fruit or vegetables for 6 weeks after the transplantation. These patients had limited follow-up dietary instruction. Of these patients, 50% (five of 10) gained 50 pounds or more above their pretransplant and/or desirable weight; two died within 1 year, and another two within 18 months with accelerated coronary atherosclerosis documented at autopsy. These results were considered unacceptable. The current diet after heart transplantation is 200 mg cholesterol, low saturated fat, low total fat, high fiber, 4 to 5 gm sodium, with limited concentrated sweets. The goals of this diet are discussed. Patients receive nutritional assessment before and after transplantation, care monitoring, and individualized dietary instruction, as well as outpatient follow-up done by the transplant team dietitian as needed. Of these patients, 20% (five of 25) gained 50 pounds or more, and one died with arteriosclerotic-related complications within the first year. The patient's nutritional status before transplant, previous eating habits, educational level, consistency in physician and team member reinforcement of diet are all major factors in long-term compliance.

Adult↗
PubMedDate not supplied

A call for help: collaborative nursing research.

Key issues related to HIV nursing research are the focus of this literature review. Results of two prior literature reviews are combined with the author's current review to serve as a basis for discussion. Findings indicate that further research is needed, particularly in the area of physiological responses to nursing care. Collaboration between clinicians and researchers is viewed as the most effective way to conduct HIV nursing research. Suggestions related to ways of facilitating collaborative research are discussed.

Attitude of Health Personnel↗