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Biomedical subjects

C Simpson

Publications and source records attributed to C Simpson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Rate-control versus conversion strategy in postoperative atrial fibrillation: a prospective, randomized pilot study.

BACKGROUND: Atrial fibrillation remains a frequent complication after heart surgery. The optimal strategy to treat the condition has not been established. Several retrospective studies have suggested that a primary rate-control strategy may be equivalent to a strategy that restores sinus rhythm. METHODS: Fifty patients with atrial fibrillation after heart surgery were randomly assigned to a strategy of antiarrhythmic therapy with or without electrical cardioversion or ventricular rate control. Both arms received anticoagulation with heparin overlapped with warfarin. The primary end point was time to conversion to sinus rhythm analyzed by the Kaplan-Meier method. Atrial fibrillation relapse after the initial conversion was monitored in the hospital over a 2-month period. RESULTS: There was no significant difference between an antiarrhythmic conversion strategy (n = 27) and a rate-control strategy (n = 23) in time to conversion to sinus rhythm (11.2 +/- 3. 2 vs 11.8 +/- 3.9 hours; P =.8). With the use of Cox multivariate analysis to control for the effects of age, sex, beta-blocker usage, and type of surgery, the antiarrhythmic strategy showed a trend toward reducing the time from treatment to restoration of sinus rhythm (P =.08). The length of hospital stay was reduced in the antiarrhythmic arm compared with the rate-control strategy (9.0 +/- 0.7 vs 13.2 +/- 2.0 days; P =.05). In-hospital relapse rates in the antiarrhythmic arm were 30% compared with 57% in the rate-control strategy (P =.24). There were no significant difference in relapse rates at 1 week (24% vs 28%), 4 weeks (6% vs 12%), and 6 to 8 weeks (4% vs 9%). At the end of the study, 91% of the patients in the rate-control arm were in sinus rhythm compared with 96% in the antiarrhythmic arm (P =.6). CONCLUSIONS: This pilot study shows little difference between a rate-control strategy and a strategy to restore sinus rhythm. Regardless of strategy, most patients will be in sinus rhythm after 2 months. A larger randomized, controlled study is needed to assess the impact of restoration of sinus rhythm on length of stay.

Aged↗
PubMed2000

The lipid peroxidation by-product 4-hydroxynonenal is toxic to axons and oligodendrocytes.

Lipid peroxidation and the cytotoxic by-product 4-hydroxynonenal (4-HNE) have been implicated in neuronal perikaryal damage. This study sought to determine whether 4-HNE was involved in white matter damage in vivo and in vitro. Immunohistochemical studies detected an increase in cellular and axonal 4-HNE within the ischemic region in the rat after a 24-hour period of permanent middle cerebral artery occlusion. Exogenous 4-HNE (3.2 nmol) was stereotaxically injected into the subcortical white matter of rats that were killed 24 hours later. Damaged axons detected by accumulation of beta-amyloid precursor protein (beta-APP) were observed transversing medially and laterally away from the injection site after intracerebral injection of 4-HNE. In contrast, in the vehicle-treated animals, axonal damage was restricted to an area immediately surrounding the injection site. Exogenous 4-HNE produced oligodendrocyte cell death in culture in a time-dependent and a concentration-dependent manner. After 4 hours, the highest concentration of 4-HNE (50 micromol/L) produced 100% oligodendrocyte cell death. Data indicate that lipid peroxidation and production of 4-HNE occurs in white matter after cerebral ischemia and the lipid peroxidation by-product 4-HNE is toxic to axons and oligodendrocytes.

Aldehydes↗
PubMed2000

Patient perception of local anesthesia for prostate brachytherapy.

Prostate brachytherapy is an increasingly popular treatment for early-stage prostate cancer. Until now, spinal or general anesthesia for the procedure has been the standard of care. For patient safety, patient convenience, and to limit use of operating facilities, the authors started performing implants routinely with local anesthesia. We present here an evaluation of patients' acceptance of prostate brachytherapy under local anesthesia. On arrival at our department on the morning of the procedure, the patient is brought into the simulator suite, an intravenous line is started, and a urinary catheter is inserted. With the patient in the lithotomy position, a 5-by-5-cm patch of perineal skin and subcutaneous tissue is anesthetized by local infiltration of 10 mL of 1% lidocaine, using a 25-gauge 5/8-inch needle. Immediately following injection into the subcutaneous tissues, the deeper tissues, including the pelvic floor and prostate apex, are anesthetized by injecting 15 mL lidocaine solution with approximately 8 passes of a 20-gauge 1-inch needle. Following subcutaneous and periapical lidocaine injections, the transrectal ultrasound (TRUS) probe is positioned to reproduce the planning images and a 3.5- or 6-inch, 22-gauge spinal needle is inserted into the peripheral planned needle tracks, monitored by TRUS. When the tips of the needles reach the prostatic base, about 1 mL of lidocaine solution is injected in the intraprostatic track, as the needle is slowly withdrawn. The lidocaine infiltration procedure takes approximately 10 to 15 minutes. Seed implantation is then performed as previously described. At the time of this report preparation, 58 of the 71 patients (81%) were interviewed, with a median follow-up of 6 months since the implant procedure. On a scale of 1 to 10, the median biopsy pain score was 4.5 compared with a median pain score with the implant procedure of 3.0. There was no clear correlation between the two scores (r = .26). There was no correlation between patients' implant pain score and the number of implant needles used, the pre-implant prostate size, or patient age. The prostate radiation dose coverage, calculated as the percent of the post-implant volume covered by the prescription isodose, averaged 88% (range, 75% to 99%). Five of the 55 patients interviewed (9%) stated that they would have preferred to have the procedure under general anesthesia. Ranked on a 1 to 5 scale, the median patient satisfaction was 5 and the average was 4.4. The substitution of local anesthesia has facilitated rapid introduction of a high-volume brachytherapy program at an institution, without requiring the allocation of significant operating room time. We are pleased with the overall level of patient comfort and satisfaction.

Aged↗
PubMed1999

Local anesthesia for prostate brachytherapy.

PURPOSE: To demonstrate the technique and feasibility of prostate brachytherapy performed with local anesthesia only. METHODS AND MATERIALS: A 5 by 5 cm patch of perineal skin and subcutaneous tissue is anesthetized by local infiltration of 10 cc of 1% lidocaine with epinephrine, using a 25-gauge 5/8-inch needle. Immediately following injection into the subcutaneous tissues, the deeper tissues, including the pelvic floor and prostate apex, are anesthetized by injecting 15 cc lidocaine solution with approximately 8 passes of a 20-gauge 1.0-inch needle. Following subcutaneous and peri-apical lidocaine injections, the patient is brought to the simulator suite and placed in leg stirrups. The transrectal ultrasound (TRUS) probe is positioned to reproduce the planning images and a 3.5- or 6.0-inch, 22-gauge spinal needle is inserted into the peripheral planned needle tracks, monitored by TRUS. When the tips of the needles reach the prostatic base, about 1 cc of lidocaine solution is injected in the intraprostatic track, as the needle is slowly withdrawn, for a total volume of 15 cc. The implants are done with a Mick Applicator, inserting and loading groups of two to four needles, so that a maximum of only about four needles are in the patient at any one time. During the implant procedure, an additional 1 cc of lidocaine solution is injected into one or more needle tracks if the patient experiences substantial discomfort. The total dose of lidocaine is generally limited to 500 mg (50 ml of 1% solution). RESULTS: To date, we have implanted approximately 50 patients in our simulator suite, using local anesthesia. Patients' heart rate and diastolic blood pressure usually showed moderate changes, consistent with some discomfort. The time from first subcutaneous injection and completion of the source insertion ranged from 35 to 90 minutes. Serum lidocaine levels were below or at the low range of therapeutic. There has been only one instance of acute urinary retention in the patients treated so far, and no unplanned admissions to the hospital or need to reschedule a patient to be implanted under general or spinal anesthesia. CONCLUSIONS: The substitution of local anesthesia has facilitated rapid introduction of a high-volume brachytherapy program at an institution that previously had none, without requiring the allocation of significant operating room time. Although the patients reported here were implanted without conscious sedation, we are starting to try various sedatives and analgesics for patients who we anticipate will have substantial anxiety with the procedure.

Adrenergic Agonists↗
PubMed1999

Acute care has an innovative approach to the bed crisis!

The regionalization of healthcare in Alberta has been instrumental in changing the way we deliver healthcare to the population. In Calgary, the restructuring involved the closing of three acute care hospitals and a significant reduction in beds per capita. This reduction in inpatient beds behooved Senior Management in acute care to be innovative and responsive to the utilization of existing resources. The Department of Patient Transition Services was conceived with a mandate to provide assistance and support in utilization management and discharge planning, administrative coordination, system support and integration support. The evolution of this unique department is described.

Acute Disease↗
PubMed1999

Bed-blocking in the National Health Service in Scotland: a study of bed-blocking in Scottish National Health Service trusts; its nature and extent.

OBJECTIVE: To determine the perceptions of managers in Scottish NHS trusts concerning bed-blocking. To help determine the causes of bed-blocking and suggest possible solutions to the problem. DESIGN: The first part of the study consisted of qualitative research interviews with key figures in NHS trusts and an examination of the existing literature on bed-blocking. This informed the second stage which was based on a questionnaire survey of senior managers in 35 trusts. SETTING: Interviews were carried out in three trusts in Forth Valley Health Board and Grampian Health Board areas. Questionnaires were sent out to 44 trusts throughout Scotland. The three trusts that were excluded from this study did not contain bed-blocking patients. SUBJECTS: Questionnaires were sent to chief executives of 44 NHS trusts in Scotland. Respondents were nominated by chief executives on the basis of their experience and understanding of bed-blocking problems within their own trust. RESULTS: Of the 44 questionnaires sent to trusts in Scotland, there were 35 responses (80%) which identified a total of 1845 beds as being blocked. The NHS secondary care-based respondents indicated that social services were responsible for 1406 bed-blocking patients in 35 trusts, an average of 40 patients per trust between August and September 1997. Some 600 of these "social services responsible" bed-blocking patients, an average of 21 patients per trust, were reported as awaiting comprehensive assessment by a social worker. In addition, 710 of these "social services responsible" bed-blocking patients, an average of 24 patients per trust, were awaiting funding authorization for a nursing home or residential home placement. NHS trusts were responsible for 237 bed-blocking patients, an average of seven patients per trust. In a further 202 cases bed-blocking was deemed to be neither the responsibility of the trust nor of social services as patients were awaiting vacancies in the patient's or carer's specific choice of residential or nursing home. CONCLUSION: Results from this study show that there would appear to be a significant number of blocked beds in NHS trust hospitals throughout Scotland. Trust staff, whilst acknowledging the complex nature of bed-blocking, perceive social services, who are responsible for the assessment, placement and financing of patients being transferred from hospitals to residential care in the community, as being responsible for the majority of these beds being blocked. It is, however, acknowledged that social services are under-funded and under-resourced. If the situation is to be improved, consideration should be given to changing service delivery processes in the context of the implementation of Designed to Care.

Bed Occupancy↗
PubMed1998

Monitoring for intraoperative awareness.

Despite advances in anesthetic technique and technology, intraoperative awareness continues to occur with alarming regularity. The psychological effects on patients and the medicolegal consequences to providers have created the need for a reliable monitor of the hypnotic component of anesthesia. A new technology known as bispectral analysis (BIS) has the potential to put an end to the devastating occurrence of intraoperative awareness, as well as improve the overall effectiveness of anesthetic delivery and the surgical experience. Applicable to almost any situation requiring sedation or general anesthesia, BIS's reliability is a real-time measure of hypnosis levels.

Anesthesia↗
PubMed1998

Preclinical antitumor efficacy of analogs of XK469: sodium-(2-[4-(7-chloro-2-quinoxalinyloxy)phenoxy]propionate.

A series of quinoxaline analogs of the herbicide Assure was found to have selective cytotoxicity for solid tumors of mice in a disk-diffusion-soft-agar-colony-formation-assay compared to L1210 leukemia. Four agents without selective cytotoxicity and 14 agents with selective cytotoxicity were evaluated in vivo for activity against a solid tumor. The four agents without selective cytotoxicity in the disk-assay were inactive in vivo (T/C > 42%). Thirteen of the fourteen agents with selectivity in the disk-assay were active in vivo (T/C < 42%). Five of the agents had curative activity. These five agents had a halogen (F, Cl, Br) in the 7-position (whereas Assure had a CI in the 6 position). All agents with curative activity were either a carboxylic acid, or a derivative thereof, whereas Assure is the ethyl ester of the carboxylic acid. All other structural features were identical between Assure and the curative agents. Assure had no selective cytotoxicity for solid tumors in the disk-assay, and was devoid of antitumor activity. The analog XK469 is in clinical development.

Animals↗
PubMed1998

An in vitro investigation of multi-layer bandages.

This study compares the elastic properties of a number of different bandages both in the non-sterile condition and after sterilisation by autoclaving at 134-138 degrees C. Results suggest that, although some products can withstand sterilisation, the performance of some elasticated and coated bandages is adversely affected by excessive heat.

Bandages↗
PubMed1997

Mental health. Nought for their comfort.

The development of resource centres works against mental health users being seen in GPs' surgeries. The community mental health team needs to be linked to inpatient services. Measuring activity is not a valid way of assessing service quality. Mental health inquiries are useless as learning exercises. The money and time they absorb would be better spent on remedying well-known problems in mental health services.

Benchmarking↗
PubMed1997

The impact of heart health promotion on coronary heart disease lifestyle risk factors in schoolchildren: lessons learnt from a community-based project.

A community health promotion project called Action Heart was undertaken in two electoral wards in Rotherham to try to change lifestyles of people. Schools were included within the project. Coronary heart disease lifestyle risk factors were measured at baseline and after a three year period in the intervention area and a similar control area. Lifestyle factors in schoolchildren were measured separately from adults using a different instrument. The post intervention survey of adults and economic evaluation demonstrated that Action Heart had achieved cost-effective estimated health gains. In the schoolchildren however, a mixture of positive and negative risk factor changes in both areas was demonstrated. Significant changes in lifestyle risk factors in schoolchildren were not elicited using this approach. The possible reasons for the lack of impact on lifestyle risk factors in schoolchildren are examined and the implications for further work explored.

Adolescent↗
PubMed1996

Hypersensitivity pneumonitis-like reaction and occupational asthma associated with 1,3-bis(isocyanatomethyl) cyclohexane pre-polymer.

Twenty-three of 34 workers who had worked in the injection molding operation making polyurethane foam parts at an automobile parts manufacturing plant developed respiratory symptoms and/or systemic symptoms over a 2-month period following the full production use of a new diisocyanate paint that contained 1,3-bis(isocyanatomethyl)cyclohexane pre-polymer (BIC)(CAS #75138-76-0, 38661-72-2). At 3 months, all subjects underwent an interview, physical examination, pre- and post-shift pulmonary function tests, and either methacholine challenge test or bronchodilator challenge at an occupational health clinic. The most frequently cited symptoms were dyspnea (65%), cough (61%), chest tightness (57%), chills (57%), wheezing (30%), and myalgias, arthralgias, and nausea (26%). Thirteen subjects had either a positive methacholine challenge test or a positive response to bronchodilator challenge, making the overall prevalence of airway hyperresponsiveness 38%. The overall prevalence of hypersensitivity pneumonitis-like reactions among line operators in the injection molding process was 27%. This disease outbreak suggests that 1,3-bis(isocyanatomethyl)cyclohexane pre-polymer may cause asthma and hypersensitivity pneumonitis-like reactions. The use of BIC was discontinued 6 months after the first workers developed symptoms.

Adult↗
PubMed1996

Neuropeptide Y, the hypothalamus and the regulation of energy homeostasis.

Neuropeptide Y (NPY) neurones in the arcuate nucleus of the rodent hypothalamus may play a key role in responding to reductions in body energy stores with appropriate changes in energy homeostasis, namely an increase in food-seeking behaviour and hyperphagia, together with a reduction in heat production by brown adipose tissue. These adaptive responses are mimicked by the injection of NPY into the main sites of projection of the NPY neurones, and animals that are threatened by energy deficits (e.g. through starvation or insulin-deficient diabetes) show increased activity of these neurones. Genetically obese rodents also show hyperactivity of the NPY neurones, which is inappropriate to their energy needs and may contribute to their hyperphagia, reduced energy expenditure and excessive weight gain. The NPY neurones may be inhibited by insulin and leptin, which may both serve as signals of peripheral fat mass. Ultimately, characterization of the specific "feeding' receptors which mediate NPY's central effects on energy homeostasis may provide opportunities for designing drugs to manipulate and appetite and energy balance in man, notably obesity and the cachexia commonly associated with malignancy and chronic infection.

Animals↗
PubMed1994

Packing selection of Bacillus lentus subtilisin and a site-specific variant.

The crystallization of a variant of Bacillus lentus subtilisin and the native enzyme was achieved using identical conditions. The variant B. lentus was found to grow in two crystal forms, form 1 and form 2, whereas the native B. lentus subtilisin enzyme crystallized in only one, form 1. Form 2 crystals, once obtained, were found to grow much more rapidly than form 1 crystals. The lattice contacts and structural changes giving both crystal forms have been examined. The results show that crystal form 2 has a more complex network of interactions. There is also a small surface conformational change in the form 2 structure relative to the native and variant form 1 crystals and at least two solvent molecules bound to the enzyme in crystal form 1 are displaced in crystal form 2. In addition, a site specific substitution in the variant at position 27 induces a 'short' lattice contact which does not exist in the native B. lentus or the form 2 variant B. lentus. These results suggest that in some circumstances engineered variants could be designed to crystallize more rapidly than the native enzyme.

Journal Article↗
PubMed1994

Complexity of the healthcare crisis in rural America.

Because osteopathic physicians comprise 15.3% of all physicians in small rural counties, while making up only 5.1% of the nation's physicians, the solutions to the healthcare crisis for rural America are of special interest to them. The authors explore the incredible diversity of rural communities and the difficulty with defining the term "rural." They give the background of efforts to address rural health problems and the reasons accessible healthcare--available, acceptable and affordable--has been so elusive in rural settings. The authors also explain the relative success of the osteopathic medical profession and address the role osteopathic physicians can play in the future. Finally, they explore the exciting new possibilities that telemedicine offers.

Health Care Reform↗