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J Sweeney

Publications and source records attributed to J Sweeney.

At least 37 records · Page 2Linked to original sources
PubMed1997

Identification of metallothionein receptors in human astrocytes.

Metallothionein (MT) isoforms are low molecular weight (6000-7000 Da) zinc binding proteins containing 60-68 amino acid residues, 25-30% cysteine, no aromatic amino acids, and binding between 5-7 g zinc/mol of protein. Since the synthesis of MT is induced by endotoxin, cytokines, and glucocorticoids, MT is now considered to be an acute phase protein protecting against oxygen radicals and oxidative damages caused by inflammation, tissue injury, and stress to the central nervous system. By postulating that a specific mechanism must exist to foster the induction of MTs I and II by numerous and diversified factors, we searched for and identified for the first time, MT receptors on U373MG cell membrane preparations, by using fluoresceinated MT I isoform probe; and by employing cysteine, glutathione, and four MT isoforms to determine high affinity and specific binding. MT receptors revealed a Kd value of 0.84 nM and a Bmax of 99.82 fmol/mg protein. Moreover, MT receptors were found in greater density on the surface of aggregated astrocytes. We postulate that conditions or agents generating reactive oxygen species may influence the expression of MT receptors.

Amino Acid Sequence↗
PubMed1997

Combined PTCA and aortic valvuloplasty for acute myocardial infarction complicated by severe aortic stenosis and cardiogenic shock.

Percutaneous aortic valvuloplasty (PAV) performed in patients with critical aortic stenosis has been shown to increase aortic valve area, decrease aortic valve gradient, and improve left ventricular function. However, the procedure is limited by rapid restenosis. Aortic valvuloplasty in the setting of critical aortic stenosis with cardiogenic shock can be a life-saving procedure, although morbidity and mortality remain high. We describe a patient with critical aortic stenosis who presented with an acute anterior myocardial infarction treated with primary angioplasty. Despite rapidly achieving patency of the culprit vessel, the patient spiraled into cardiogenic shock, which prompted an emergent PAV.

Aged↗
PubMed1997

Multielectrode nerve cuff stimulation of the median nerve produces selective movements in a raccoon animal model.

In this study, an electrode system consisting of twelve small platinum dot electrodes imbedded in a spiral silicone rubber insulating cuff was used to investigate the feasibility of selective (regional) stimulation of the median nerves of the raccoon. Acute experiments in four raccoons consisted of functional responses observations, isometric force recordings from tendon attachments and postmortem fascicular mapping. Functional responses (elbow, wrist and/or digit flexion, pronation and/or thumb abduction) to selective stimulation were noted as dependent upon cuff electrode configuration (longitudinal tripole with and without field steering, as well as a transverse bipolar arrangement) and current level (threshold, 1/2 maximal, maximal). Muscle force recruitment curves (force as a function of stimulus amplitude) were plotted for flexor digitorum superficialis, flexor digitorum profundus, flexor carpi radialis, palmaris longus and pronator teres of three raccoons. Fascicular maps at the level of the nerve cuff were created indicating the approximate position of innervation to each of the aforementioned muscles, as well as other innervation such as paw fascicles, sensory fascicles, and elbow innervation (such as coracobrachialis). The greatest selectivity was observed at or near threshold current levels. In all four raccoons studied, a threshold electrode choice and stimulation strategy could be identified enabling selective production of either digit flexion, wrist flexion and/or digit and wrist flexion. It was possible to elicit a selective pronation response at threshold in three of the four animals. Selective elbow flexion at threshold could be produced in all four experiments. With stronger currents, additional movements were usually induced. The raccoon therefore appears to be a suitable, if challenging, animal model for further development of not only nerve cuff electrode approaches but perhaps other stimulation electrode technologies prior to human neuroprosthetic studies.

Animals↗
PubMed1996

The raccoon as an animal model for upper limb neural prosthetics.

The raccoon was evaluated as an animal model for upper limb neural prosthetics. This animal was selected primarily because the functional use of its forelimb mimics in many ways the usage in humans and because of its optimal size and commercial availability. Eight cadaver and fresh specimen forearms were dissected. Important characteristics of the raccoon forearm were: 1) large muscles in the volar forearm, 2) large digits in the paw that appear more similar to humans than to other species such as cat or dog, 3) persistence of two median nerve cords into the forearm, 4) no separation of individual tendons of flexor digitorum superficialis and flexor digitorum profundus in the carpal tunnel, 5) a small thumb digit with little function and 6) a primary origin of flexor policis longus on the proximal ulna with a secondary origin on the radius. Four animals were anesthetized and responses of the forearm and paw to stimulation of the volar forearm muscles with percutaneous electrodes were evaluated. A pair of stimulating electrodes was placed in each of four muscles or muscle groups. Recording electrodes were placed in two muscles which showed the greatest separation of muscle movements to stimulation. Stimulation currents just above threshold produced discrete motion as well as recordable EMG M-waves. Incremental increases in stimulation current produced an increase in M-wave amplitude up to a maximal stimulating current. Torque recordings for pronation, wrist flexion and finger flexion showed graded and selective responses. These results including anatomical descriptions indicate both the limitations of this animal model and its potential use in the development of upper limb neural prosthetics. We conclude that the raccoon model may be superior to other nonprimate animal models such as the cat because of its extensive forearm and paw movements.

Animals↗
PubMed1996

Association between HIV distal symmetric polyneuropathy and Mycobacterium avium complex infection.

OBJECTIVES: Pronounced infiltration of activated macrophages occurs in the peripheral nerves of patients with HIV distal symmetric polyneuropathy (DSPN). Mycobacterium avium complex (MAC) is a common facultative intracellular parasite of the macrophage in advanced HIV disease and may induce macrophage activation. Whether MAC disease is associated with DSPN was examined prospectively. METHODS: One hundred and fifty consecutive patients with HIV infection were assessed for the probability of DSPN. Blood cultures for MAC were performed, independently of neurological assessment, as part of the investigation of unexplained fever, anaemia, weight loss, or, less commonly, diarrhoea. RESULTS: There were 20 patients with possible, 14 with probable, and 22 with definite HIV DSPN. Blood cultures for MAC were performed on 80 patients, of whom 39 were positive and 41 negative. The test for trend, when corrected for CD4 count, disclosed a significant association (P = 0.01). There was no statistically significant association between DSPN and cytomegalovirus (CMV) disease. CONCLUSION: Coinfection of the macrophage by MAC may further activate the HIV infected macrophage thereby accelerating the elaboration of neural toxins or MAC infection of the macrophage itself may lead to the production of neural toxins.

Adult↗
PubMed1996

Uveitis associated with rifabutin and macrolide therapy for Mycobacterium avium intracellulare infection in AIDS patients.

OBJECTIVE: Uveitis has been increasingly recognised as a side effect of rifabutin regimens in the prophylaxis and treatment of Mycobacterium avium intracellulare (MAI) infection. This study describes the clinical features and analyses the factors associated with rifabutin induced uveitis. DESIGN: Retrospective observational study. SETTING: Tertiary care institution, The Royal Hospitals NHS Trust, London. PATIENTS: 68 HIV seropositive individuals receiving rifabutin for prophylaxis or treatment of MAI infection. RESULTS: 11 episodes of uveitis occurred in 10 different individuals at a median of 62 days. The disease was bilateral in four and unilateral in the remainder. All subjects experienced ocular pain and photophobia and 9 individuals had a significant reduction in visual acuity. Uveitis was treated with mydriatics and topical steroids and resolved in all cases when rifabutin was stopped. The risk of uveitis was significantly increased with concurrent clarithromycin therapy, Odds Ratio 13.08, 95% Confidence Interval 1.98 to 83.12. CONCLUSION: Rifabutin can cause a reversible uveitis. This risk is increased with concurrent clarithromycin therapy. Adverse drug interactions can be an important cause of morbidity in patients with advanced HIV disease.

AIDS-Related Opportunistic Infections↗
PubMed1996

Laparoscopic versus open appendectomy: a prospective randomized trial of 81 patients.

OBJECTIVE: To compare the efficacy of laparoscopic appendectomy (LA) and open appendectomy (OA) in the treatment of acute appendicitis. DESIGN: A prospective randomized trial. SETTING: A university teaching hospital. PATIENTS: Eighty-one patients with a diagnosis of acute appendicitis were prospectively randomized to undergo either LA or OA. The two groups were matched for age and sex. INTERVENTIONS: LA or OA. MAIN OUTCOME MEASURES: Number of days in hospital and time to full recovery. RESULTS: The mean hospital stay for LA was 3.23 days compared with 3.03 days for OA (p < 0.001). The mean number of narcotic injections required for patients in the LA group was 4.05 compared with 5.58 for patients in the OA group (p < 0.001). The mean time to complete recovery for patients in the LA group was 9.0 days compared with 16.2 days for patients in the OA group (p < 0.001). The mean operative time for LA was 73.8 minutes compared with 45.0 minutes for OA (p < 0.001). Three patients in the LA group had intra-abdominal abscesses (p > 0.25). No significant difference in wound infection rates was demonstrated (p > 0.05). Similarly, pain scores at 7 and 28 days showed no significant difference (p > 0.05). CONCLUSIONS: With LA significantly fewer narcotic injections are required and there is a more rapid return to normal activities. LA takes longer to perform and was associated with three intra-abdominal abscesses. In cases of simple acute appendicitis the hospital stay for LA is significantly shorter.

Adult↗
PubMed1995

The future role of the mental health nurse.

In the light of rapidly changing mental health care provision, education programmes need to adequately prepare practitioners for the future. Legislative and policy initiatives, the professional and research literature, and local mental health priorities are reviewed to guide educational developments. The reliance on skill development associated primarily with problem removal and short term care is questioned. Current and future trends in mental health nursing education challenge educationalists to place greater emphasis on the development of skills to empower clients with severe and persistent mental health problems in diverse care settings.

Forecasting↗
PubMed1994

Radiofrequency catheter ablation as a cure for idiopathic tachycardia of both left and right ventricular origin.

OBJECTIVES: The purpose of this study was 1) to investigate the efficacy and safety of radiofrequency energy catheter ablation as curative treatment for idiopathic tachycardia of both left and right ventricular origin, and 2) to compare the usefulness of different methods used to map the site of origin of idiopathic ventricular tachycardia. BACKGROUND: Percutaneous radiofrequency catheter ablation has been used with dramatic success in the treatment of patients with Wolff-Parkinson-White syndrome, atrioventricular node reentrant tachycardia and bundle branch reentrant tachycardia. Limited data are available on the use of radiofrequency energy catheter ablation as curative treatment for idiopathic tachycardia of both left and right ventricular origin. METHODS: Twenty-eight consecutive patients (13 to 71 years old) presenting with idiopathic ventricular tachycardia were enrolled in the study. The site of origin of both left and right ventricular tachycardia was mapped using earliest endocardial activation times during tachycardia and by pace mapping. These mapping techniques were compared. RESULTS: Radiofrequency ablation was successful in all eight patients (100%) with left ventricular tachycardia. Tachycardia recurred in one patient. The ablation procedure was complicated by mild aortic insufficiency in one patient. Right ventricular outflow tract tachycardia was successfully ablated in 17 (85%) of 20 patients. The success rate at follow-up was 85%. In one patient, the ablation procedure was complicated by acute ventricular perforation and death. Pace maps from successful ablation sites were better than pace maps from unsuccessful sites (p < 0.004). Endocardial activation times at successful ablation sites were not different from unsuccessful sites (p < 0.13). CONCLUSIONS: Radiofrequency catheter ablation is an effective treatment for idiopathic ventricular tachycardia. The site of origin of tachycardia is best identified using pace mapping. Significant complications can occur and should be considered in the risk/benefit analysis for each patient.

Adolescent↗
PubMed1994

Nursing for change: the orientations and values of Project 2000 diploma and undergraduate nursing students.

The introduction of pre-registration nursing degree and diploma programmes in the United Kingdom has provoked considerable scrutiny of a range of issues such as funding arrangements, links between colleges of nursing and midwifery and higher education and the impact of the new courses on education and service provision. Less attention has been devoted to the changing orientations and values of diploma and undergraduate students during their courses of study. The parallel commencement in 1991 of 3-year undergraduate and diploma programmes in Leicestershire provided an opportunity to chart the changing orientations (personal, political, ethical, professional and academic) of two cohorts of students matched by age, gender and branch programme. Research is being undertaken, a primary aim of which is to assess the changes that occur in these orientations over time and to relate these to the educational progression of the students through successive phases of their respective courses. The focus of the research concerns the student's personal experience and developing insights into health, nursing and care delivery. This paper seeks to provide an overview of the literature relevant to the study.

Attitude of Health Personnel↗
PubMed1994

Adverse effects of drugs used in the management of opportunistic infections associated with HIV infection.

Pneumocystis carinii pneumonia (PCP) is one of the most common AIDS-defining diagnoses. First-line therapy is cotrimoxazole (trimethoprim-sulfamethoxazole), despite a high incidence of toxic effects, and a greater incidence of hypersensitivity reactions among HIV-positive patients compared with the seronegative population. Alternative agents such as intravenous pentamidine, or clindamycin with primaquine, and trimethoprim with dapsone, also have a wide range of serious adverse effects, but remain treatment options. Atovaquone appears promising for the treatment of both PCP and toxoplasmosis, and has a lower reported incidence of toxicity than the alternative agents. The most toxic antifungal drugs are reserved for serious infections, such as cryptococcal meningitis. Liposomal amphotericin B has less renal toxicity than standard formulations, and exemplifies that new formulations of existing drugs, although often expensive, may have a better adverse effect profile. There are 2 different drugs currently available for cytomegalovirus (CMV) infections, ganciclovir and foscarnet. Both have a high incidence of serious adverse effects; ganciclovir mainly causes bone marrow toxicity and foscarnet leads to renal toxicity. The drugs used for mycobacterial infection (including mycobacteria as well as tuberculosis) have a wide range of adverse effects, particularly skin rashes and drug-induced hepatitis. Some of these compounds are quite new, such as rifabutin and clarithromycin, and it is important to be ever vigilant for previously unreported adverse effects.

AIDS-Related Opportunistic Infections↗
PubMed1993

The effect of pregnancy on the response to the TxA2/PGH2 analogue U-46619 in rabbits.

We compared the hemodynamic actions of U-46619, a stable thromboxane A2 (TxA2) prostaglandin H2 (PGH2) analogue, in nonpregnant (NP) rabbits with those observed in late pregnant (P) rabbits. An intravenous injection of U-46619 (10 micrograms) to each of eight NP chronically instrumented rabbits (mean body weight 3.4 kg) induced an immediate (1 min) and reversible fall of cardiac output (CO, 66%) and mean arterial pressure (MAP, 41%, both P < 0.01). P rabbits (n = 6, mean body weight 3.8 kg), however, responded with an elevation of MAP (5%, P < 0.02) upon intravenous injection of the drug (10 micrograms), while CO remained unchanged. The fall of CO in NP rabbits was associated with the temporary disappearance of a fraction of circulating platelets between the superior vena cava and the aortic arch. The number of platelets at 30 and 60 s after U-46619 was reduced (P < 0.05) by 14 and 20% respectively in the aortic blood, whereas caval platelet counts were unchanged until 90 s (-6%, P < 0.05). In contrast, intraaortic administration of this drug (10 micrograms) to NP rabbits resulted in neither thrombocytopenia nor hypotension. U-46619 (10-30 micrograms i.v.) caused no decrease in platelet count in the aorta of P rabbits. In vitro, U-46619-induced aggregation of platelets harvested from P rabbits was also blunted (P < 0.001). This could not be attributed to reduced affinity or number of platelet thromboxane receptors. The data indicate that U-46619 induces a fall of arterial pressure simultaneous with intravascular platelet aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗