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Biomedical subjects

L Sebastian

Publications and source records attributed to L Sebastian.

14 recordsLinked to original sources
PubMed1999

Neurotrophic factors [activity-dependent neurotrophic factor (ADNF) and basic fibroblast growth factor (bFGF)] interrupt excitotoxic neurodegenerative cascades promoted by a PS1 mutation.

Although an excitotoxic mechanism of neuronal injury has been proposed to play a role in chronic neurodegenerative disorders such as Alzheimer's disease, and neurotrophic factors have been put forward as potential therapeutic agents, direct evidence is lacking. Taking advantage of the fact that mutations in the presenilin-1 (PS1) gene are causally linked to many cases of early-onset inherited Alzheimer's disease, we generated PS1 mutant knock-in mice and directly tested the excitotoxic and neurotrophic hypotheses of Alzheimer's disease. Primary hippocampal neurons from PS1 mutant knock-in mice exhibited increased production of amyloid beta-peptide 42/43 and increased vulnerability to excitotoxicity, which occurred in a gene dosage-dependent manner. Neurons expressing mutant PS1 exhibited enhanced calcium responses to glutamate and increased oxyradical production and mitochondrial dysfunction. Pretreatment with either basic fibroblast growth factor or activity-dependent neurotrophic factor protected neurons expressing mutant PS1 against excitotoxicity. Both basic fibroblast growth factor and activity-dependent neurotrophic factor stabilized intracellular calcium levels and abrogated the increased oxyradical production and mitochondrial dysfunction otherwise caused by the PS1 mutation. Our data indicate that neurotrophic factors can interrupt excitotoxic neurodegenerative cascades promoted by PS1 mutations.

Alzheimer Disease↗
PubMed1999

Increased vulnerability of hippocampal neurons from presenilin-1 mutant knock-in mice to amyloid beta-peptide toxicity: central roles of superoxide production and caspase activation.

Many cases of early-onset inherited Alzheimer's disease (AD) are caused by mutations in the presenilin-1 (PS1) gene. Overexpression of PS1 mutations in cultured PC12 cells increases their vulnerability to apoptosis-induced trophic factor withdrawal and oxidative insults. We now report that primary hippocampal neurons from PS1 mutant knock-in mice, which express the human PS1M146V mutation at normal levels, exhibit increased vulnerability to amyloid beta-peptide toxicity. The endangering action of mutant PS1 was associated with increased superoxide production, mitochondrial membrane depolarization, and caspase activation. The peroxynitrite-scavenging antioxidant uric acid and the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone protected hippocampal neurons expressing mutant PS1 against cell death induced by amyloid beta-peptide. Increased oxidative stress may contribute to the pathogenic action of PS1 mutations, and antioxidants may counteract the adverse property of such AD-linked mutations.

Alzheimer Disease↗
PubMed1995

The effect of patient controlled analgesia and continuous epidural infusion on length of hospital stay after total knee or total hip replacement.

The purpose of this study was to determine the correlation between patient controlled analgesia and continuous epidural analgesia after total knee or total hip replacement on the length of hospital stay. Stress responses to postoperative pain, including decreased mobility, compromised respiratory function, increased catecholamine release, and hypercoagulation, may adversely affect patient recovery, thus lengthening hospital stay. A retrospective chart review of 127 adult, American Society of Anesthesiology (ASA) I, II, or III, patients who had undergone total knee arthroplasty (TKA) or total hip replacement (THR) was obtained. One patient group received epidural anesthesia and postoperative analgesia (EAA) through continuous catheter infusion of bupivacaine or preservative free morphine. The second group underwent general anesthesia and postoperative patient controlled anesthesia (G-PCA) of meperidine hydrochloride or morphine. Length of stay (LOS) was defined as the time period beginning with admission to the post-anesthesia care unit (PACU) until 10 AM the day of discharge. The mean LOS, in hours, for EAA-morphine was 121; compared with EAA-bupivacaine, 142; G-PCA-meperidine, 134; and G-PCA-morphine, 142. These findings were not statistically significant at P = 0.054. LOS did not correlate with age, weight, height, type or surgery, or the ASA classification. Further research into the effectiveness of continuous infusion of epidural bupivacaine and epidural morphine and their impact on LOS may be warranted.

Analgesia, Epidural↗
PubMed1994

The defining characteristics of support. Results of a research project.

Support is a central concept in nursing practice; not only for psychiatric nurses, but for all nurses. Yet, the ambiguity about the definition of support is troubling. More importantly, nurses are "doing things" to and for patients, but are these interventions truly supportive? What kinds of support do our patients want and need? As nursing advances towards a scientific basis for practice, we must be clear about the what and why of our actions (Sebastian, 1990). As nurses become more outcome oriented, we must know what patients value in their treatment. This study is an initial attempt to clarify for psychiatric nurses the concept of support; may it be the first of many.

Adult↗
PubMed1991

Third party reimbursement for nurses in advanced practice.

The author contends that nursing has a challenge ahead: to educate consumers, legislators, and insurance companies that nurses in advanced practice are cost-effective and provide quality care. The author describes her own legislative struggle with Blue Cross/Blue Shield. She urges nurses to attain the potential inherent in the clinical nurse specialist role by becoming actively involved in advocation for third-party reimbursement.

Insurance, Health, Reimbursement↗
PubMed1991

Promoting object constancy. Writing as a nursing intervention.

1. Object constancy is an important developmental milestone that many psychiatric patients have not achieved. 2. Asking patients to write down thoughts and feelings will assist the nurse in reinforcing a continuous experience of self as a necessary antecedent to self and object constancy. 3. Object constancy allows the patient to be more autonomous in relationships. Writing will help the patient become more independent in managing thoughts and feelings. 4. Using an object relations framework for this commonly prescribed nursing intervention will assist nurses in providing a focus and goal for the use of writing.

Human Development↗
PubMed1990

Whose structure is it anyway?

While "structure" is a term that is widely used in psychiatric nursing practice, few nurse authors have clearly defined the concept. This article offers an operational definition of structure, and proposes a theoretical basis to the client's need for structure. A case presentation, as well as characteristics of an effective structure, are also described.

Activities of Daily Living↗