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Biomedical subjects

P Sullivan

Publications and source records attributed to P Sullivan.

269 records · Page 15Linked to original sources
PubMedDate not supplied

Epidural abscess causing cauda equina syndrome.

BACKGROUND: Spinal epidural abscesses are uncommon but are well documented in the literature as a serious causes of mortality and long-term neurological morbidity. AIM: We describe a case of a 57-year-old female who presented to Accident and Emergency with an acute exacerbation of long standing mild lower back pain with symptoms of cauda equina syndrome and a systemic infective process. CONCLUSION: The diagnosis of this condition requires a high index of suspicion. This report demonstrates that with adequate decompression and appropriate antimicrobial treatment a good outcome is achievable.

Acute Disease↗
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Prenatal dexamethasone or stress but not ACTH or corticosterone alter sexual behavior in male rats.

Prenatal maternal stress in rats and mice can demasculinize and feminize the sexual behavior of adult male offspring. Causal mechanisms are unknown, but one attractive hypothesis is that stress activation of maternal adrenal glucocorticoid secretion is the responsible agent. To test this hypothesis, pregnant rats were exposed to a variety of substances which enhance glucocorticoid actions. These included ACTH (20 IU of a gel preparation, SC once daily), corticosterone (CORT; 7 mg/kg SC in oil, three times daily), or dexamethasone (DEX; 0.1 mg/kg, SC once daily). Controls included noninjected dams and a positive stress control group (restraint under bright lights three times daily). All treatments reduced maternal weight gain, DEX most potently. No treatment altered litter size, stillbirths, or sex ratio, but DEX reduced weight at birth, an effect still seen at postnatal day 85. DEX, CORT, and stress reduced male adrenal weight at birth, while DEX and CORT altered sexual differentiation as measured by anogenital distance. Stress impaired adult male sexual performance but not the lordosis quotient following exposure of animals to stud males. DEX affected both measures. No other treatment had any significant effect on sexual behavior. No treatment altered plasma LH levels, either basal or in response to an estrogen challenge in adult gonadectomized males. In adulthood there was no treatment effect on stress reactivity, measured behaviorally or by plasma glucocorticoids. Correlational analysis revealed that weight gain during pregnancy was the single best predictor of subsequent sexual performance. It is concluded that prenatal dexamethasone exposure demasculinizes and feminizes male offspring.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
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Cis-acting human ApoE tissue expression element is associated with human pattern of intraneuronal ApoE in transgenic mice.

Apolipoprotein E polymorphic variants (ApoE-epsilon2, epsilon3, and epsilon4) are associated with the age of onset distribution and risk of Alzheimer disease. The question of whether ApoE is expressed at a comparatively low level in human neurons compared to astrocytes, or whether ApoE enters neuronal cytoplasm via altered endosomal metabolism is important to understanding potential pathogenic roles for ApoE as a susceptibility gene in Alzheimer disease. ApoE deficient ("knock-out") mice received large human genomic DNA fragment transgenes for each of the three common apoE alleles. All transgenic mice demonstrated glial/astrocytic (normal rodent pattern), as well as cortical intraneuronal ApoE immunoreactivity with all three human isoforms and at multiple ApoE human allele doses (Xu et al. (32)). To test whether ApoE intraneuronal immunoreactivity was due to ApoE gene sequences between mouse and human, we examined another set of mice constructed using targeted replacement so that the human ApoE gene was placed under mouse gene promoters. Current analyses show that targeted replacement recombinant mice show normal rodent glial expression pattern, but no ApoE neuronal immunoreactivity through six months of age compared to large human genomic DNA fragment transgenic mice, which show neuronal content of ApoE throughout adult life. We conclude that cis-acting DNA sequences, rather than the specific sequence of the ApoE gene, may be responsible for low levels of transcription activity in cortical neurons.

Alleles↗
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Boundary detection of retinoblastoma tumors with neural networks.

Consistent and accurate measurement of retinoblastoma tumors is of important clinical value for treatment management. This paper presents an algorithm for the determination of retinoblastoma (RB) tumor to assist in the determination of tumor volume changes throughout treatment periods. The result of the development of a neural network approach for the analysis of three-dimensional ultrasound images shows that it is possible to identify retinoblastoma tumors and accurately determine the front and back boundary of the tumor. The algorithm used was a soft competitive learning network with two inputs. The outputs of the network identify the eye, the tumor, and the back of the eye.

Algorithms↗
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A twin study of chronic fatigue.

OBJECTIVE: The etiology of chronic fatigue syndrome is unknown, but genetic influences may be important in its expression. Our objective was to assess the role of genetic and environmental factors in unexplained chronic fatigue. METHODS: A classic twin study was conducted using 146 female-female twin pairs, of whom at least one member reported > or =6 months of fatigue. After completing questionnaires on symptoms, zygosity, physical health, and a psychiatric interview, twins were classified using three increasingly stringent definitions: 1) chronic fatigue for > or =6 months, 2) chronic fatigue not explained by exclusionary medical conditions, and 3) idiopathic chronic fatigue not explained by medical or psychiatric exclusionary criteria of the chronic fatigue syndrome case definition. Concordance rates in monozygotic and dizygotic twins were calculated for each fatigue definition along with estimates of the relative magnitude of genetic and environmental influences on chronic fatigue. RESULTS: The concordance rate was higher in monozygotic than dizygotic twins for each definition of chronic fatigue. For idiopathic chronic fatigue, the concordance rates were 55% in monozygotic and 19% in dizygotic twins (p =.042). The estimated heritability in liability was 19% (95% confidence interval = 0-56) for chronic fatigue > or =6 months, 30% (95% confidence interval = 0-81) for chronic fatigue not explained by medical conditions, and 51% (95% confidence interval = 7-96) for idiopathic chronic fatigue. CONCLUSIONS: These results provide evidence supporting the familial aggregation of fatigue and suggest that genes may play a role in the etiology of chronic fatigue syndrome.

Adult↗
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Effects of cephalothin, cefazolin, and cefmetazole on the hemostatic mechanism in normal dogs: implications for the surgical patient.

Twenty-six female beagles were used to evaluate the effects of intravenous and long-term subcutaneous administration of cephalothin, cefazolin, and cefmetazole on platelet function and the coagulation cascade. Platelet aggregation in response to an adenosine diphosphate (ADP) agonist, bleeding time, platelet count, platelet size, prothrombin time (PT), and activated partial thromboplastin times (aPTT) were evaluated before and 90 minutes after two intravenous doses (22 mg/kg) of cephalothin, cefazolin, and cefmetazole given at 90-minute intervals. Dogs given saline injections were used as controls. Platelet count, platelet size, PT, and aPTT were evaluated after 7 days of subcutaneous administration of saline, cefazolin, and cefmetazole (22 mg/kg every 8 hours). A significant decrease in platelet aggregation in response to ADP was detected 90 minutes after intravenous administration of cephalothin. Bleeding time was increased significantly 90 minutes after intravenous administration of cefmetazole. Platelet size was decreased significantly 24 hours after onset of the study in all animals, including controls. No significant changes in platelet count, platelet size, PT, or aPTT were detected after 7 days of subcutaneous administration. Cefazolin had no adverse effects on platelet aggregation in response to ADP, bleeding time, platelet count, platelet size, PT, or aPTT. Therefore, cefazolin should be considered as a perioperative antibiotic in dogs with conditions predisposing to hemostatic complications.

Animals↗
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Anxiety, anger, and neurogenic tone at rest and in stress in patients with primary hypertension.

To determine whether basal blood pressure or pressor responses to stress are related to sympathetic nerve tone or to psychological factors in hypertensives, 15 hypertensives and 13 normotensives were studied by mean of a self-administered questionnaire, isometric handgrip exercise (IHE), and the mental stress of serial subtraction. Plasma norepinephrine (NE), epinephrine (E), blood pressure (BP) and heart rate (HR) were measured before and at the end of IHE and mental stress. A greater number of hypertensives had suppressed anger (p less than 0.01) and scored higher on anxiety trait (p less than 0.01) and depression (p less than 0.05). Prestress (IHE and mental) BP and NE values were significantly greater in hypertensives (all p less than 0.01). During IHE, both groups had a significant increase of BP, HR, and NE (all p less than 0.01) but E rose in hypertensives only (p less than 0.05). The percentage change of BP, HR, NE, and E during IHE was similar in both groups. The changes of BP and HR were not related to NE or E. During mental stress, HR (p less than 0.01) and E (p less than 0.05) increased in both groups. However, BP (systolic and diastolic) increased in normotensives only (p less than 0.01). Plasma NE contents were unchanged in both groups. There were significant positive correlations of anxiety trait with systolic BP (p less than 0.05), diastolic BP (p less than 0.05), and NE (p less than 0.05) and E (p less than 0.05). Although hypertensives had increased neurogenic tone related perhaps to inward anger and anxiety, the percentage responses of neurogenic tone and BP to IHE were equivalent to those of normotensives. The challenge of serial subtraction did not elicit further noradrenergic or pressor responses in hypertensives. Suppressed anger and anxiety, via increased basal neurogenic tone, may be pathogenic factors in some patients with primary hypertension.

Adult↗
PubMedDate not supplied

The effect of chronic ischemia on the primate optic nerve.

PURPOSE: To develop an in vivo model of chronic optic nerve ischemia to study the role of vascular insufficiency in the development of glaucomatous optic neuropathy. METHODS: We surgically implanted osmotically-driven mini-pumps that allowed the continuous micro-application of 0.2 micrograms/day of endothelin-1 (ET-1) into the retrobulbar optic nerve of rabbits and rhesus monkeys. ET-1 was delivered for 2 to 6 months, following which histological studies were performed. RESULTS: Both rabbits and primates experienced a 35% to 38% decrease in optic nerve blood flow with corresponding focal narrowing of the vessels supplying the optic nerve. In the rabbit model, optic disc excavation and histologic tissue loss in the anterior optic nerve resulted from the induced ischemia. CONCLUSIONS: Chronic ischemia of the primate anterior optic nerve induced with endothelin-1 infusion resulted in diffuse loss of axons without a change in the intraocular pressure.

Animals↗
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The care programme approach: a nursing perspective.

The care programme approach is part of a large body of political guidance relating to the Government's policy of caring for mentally ill patients in the community. This policy has been in operation for over three decades and still remains controversial. Recent media attention has focused on mental health care in a far from positive manner, and evidence suggests that the care programme approach has not proved a total success (Hogman, 1992; Huxley, 1993; North et al, 1993; Social Services Inspectorate, 1995). Despite this it remains the foundation on which a series of policy directives have been based over the last 5 years, and it is difficult to disagree with the fundamental philosophy, which reflects the basic principles underpinning the delivery of effective mental health care in the community. There are clear implications for psychiatric nurses, and this article outlines the crucial role that nurses working in both hospital and community settings have to play in the clinical application of the care programme approach.

Community Health Nursing↗
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Therapeutic interaction and mental health nursing.

Recent research suggests that interaction between psychiatric nurses and their patients is low. The author of this article argues that this is not a new phenomenon and that psychiatric nursing has failed to grasp its main opportunity for excellence in practice.

Health Knowledge, Attitudes, Practice↗
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Stress and burnout in psychiatric nursing.

The purpose of this literature review is to focus on the issue of occupational stress in psychiatric nursing and to examine academic work related to the concepts of stress, coping and burnout. The review concludes with comments on the implications for nursing practice, education, research and management.

Adaptation, Psychological↗
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Developing evidence--based care in mental health nursing.

For evidence-based practice to become a reality, its effects must be demonstrated clearly in the clinical situation. Practitioners must be sen to access, evaluate and apply research-based evidence in their day-to-day work. In this article, the author considers how this process could work in mental health nursing.

Evidence-Based Medicine↗
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Care and control in mental health nursing.

In this article, the author examines the complex balance between care and control in mental health nursing. He suggests that, without intervention from those leading the profession, the emphasis on control will undermine the therapeutic value of care.

Humans↗
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Needs assessment. Process and application.

This article describes the process of developing a learning needs assessment. The process includes developing a tool, collecting data, and analyzing results. Understanding the needs assessment process and the pitfalls to avoid may assist educators in implementing their own learning needs assessments.

Attitude of Health Personnel↗