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Biomedical subjects

R Stewart

Publications and source records attributed to R Stewart.

At least 19 recordsLinked to original sources
PubMed2000

Continuous pulse oximetry in acute hemiparetic stroke.

BACKGROUND AND PURPOSE: Hypoxemia can adversely affect ischemic brain tissue in laboratory animals. The aim of this study was to assess the value of early continuous monitoring with pulse oximetry in detecting arterial oxygen desaturations in patients with acute hemiparetic stroke, and the effects of oxygen administration. METHODS: Over a period of 6 months 49 consecutive patients with acute hemiparetic stroke of </=12 h duration were monitored for the first 48 h with pulse oximetry. Patients in whom arterial oxygen saturation (SaO(2)) fell beneath 96% for a period longer than 5 min were treated with oxygen administered via nasal prongs or oxygen mask. RESULTS: Thirty-one patients (63.3%) developed arterial oxygen desaturations. Of these patients 28 could effectively be treated with oxygen up to a flow-rate of 5 l/min. Only 3 patients required higher oxygen concentrations from 6 to 10 l/min. No acute adverse effects of oxygen treatment were observed. All patients with a history of cardiac and pulmonary disease developed drops in SaO(2). The occurrence of arterial oxygen desaturations was related to stroke severity (P=0.024), the presence of dysphagia (P=0.047), and older age (P=0.037). CONCLUSION: Patients with acute hemiparetic stroke frequently develop arterial oxygen desaturations. Continuous monitoring with pulse oximetry in this group of patients is a simple and useful method to detect drops in SaO(2) and to titrate oxygen administration.

Acute Disease↗
PubMed2000

Neurotrophins enhance electric field-directed growth cone guidance and directed nerve branching.

Neurotrophins play major roles in the developing nervous system in controlling neuronal differentiation, neurite outgrowth, guidance and branching, synapse formation and maturation, and neuronal survival or death. There is increasing evidence that nervous system construction takes place in the presence of dc electric fields, which fluctuate dynamically in space and time during embryonic development. These have their origins in the neural tube itself, as well as in surrounding skin and gut. Early disruption of these endogenous electric fields causes failure of the nervous system to form, or else it forms aberrantly. Nerve growth, guidance, and branching are controlled tightly during pathway construction and in vitro dc electric fields have profound effects on each of these behaviours. We have used cultured neurones to ask whether neurotrophins and dc electric fields might interact in shaping neuronal growth, given their coexistence in vivo. Electric field-directed nerve growth generally was enhanced by the simultaneous presentation of several neurotrophins to the growth cone. Under certain circumstances, more nerves turned cathodally, they turned faster, further, and in lower field strengths. Intriguingly, other combinations of dc electric field and neurotrophins (low field strength and neurotrophin 3 (NT-3) switched the direction of growth cone turning. Additionally, cathodally directed nerve growth was faster and directed branching was much more common when electric fields and neurotrophins interacted with neuronal growth cones. Given such profound changes in growth cone behaviour in vitro, neurotrophins and endogenous electric fields are likely to interact in vivo.

Animals↗
PubMed2000

Xenopus NK cells identified by novel monoclonal antibodies.

Early-thymectomized (Tx) Xenopus frogs, which are permanently deficient in T cells, are used as a model sytem for the characterization of novel monoclonal antibodies (mAb) which identify candidate NK cells at the amphibian level of evolution. Hybridomas, generated from mice immunized with splenocytes from Tx Xenopus following B cell and thrombocyte depletion, were screened by flow cytometry. Three mAb (1F8, 4D4 and 1G5) were identified that stained increased proportions of splenocytes from Tx compared with control frogs. These mAb identified lymphoid populations from Xenopus spleen, liver and gut which, after 48 h culture in growth factor-rich medium, exhibited spontanous killing of MHC-deficient allotumor targets. mAb-defined splenocytes also rapidly induced apoptosis of such tumor targets. Dual color analysis confirmed that NK cells are neither T nor B cells. Cytospins of splenocytes isolated with anti-NK mAb revealed large lymphoid cells with distinct pseudopodia. Immunohistology indicated each anti-NK mAb routinely labeled cells within the gut epithelium but NK cells were difficult to visualize in spleen sections. Western blotting of spleen, liver and intestinal lysates subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that 1G5 reacted strongly with protein bands of approximately 70 - 85 kDa, whereas mAb 1F8 and 4D4 stained less intensely, but identified similar protein bands.

Animals↗
PubMed2000

Smallest detectable difference of maximal mouth opening in patients with painfully restricted temporomandibular joint function.

Changes in maximal mouth opening reflect the impact of temporomandibular disorders and the effect of a therapeutic intervention. No information about the amount of change in maximal mouth opening with regard to reasoned decision-making is available. The smallest detectable difference, as a measure of reliability assessment, provides this information and is expressed in the unit of the measurement instrument. Twenty-five consecutive patients (5 males, 20 females) with a painfully restricted temporomandibular joint participated in this study. Measurements of maximal mouth opening were performed by two well-trained observers on two separate measurement days, one week apart. The maximal mouth opening measurements were repeated three times. Inter-observer, intra-observer, and test-retest reliability varied between 0.90 and 0.96. Inconsistency in measurement results analyzed in terms of absolute error variance, i.e. the measurement facets plus all the interactions, represented 11% of total variance. The smallest detectable difference of maximal mouth opening varied from 9 to 6 mm. For being successful in painfully restricted temporomandibular joint patients, statistically as well as clinically, the clinician has to measure at least 9 mm of improvement in maximal mouth opening. To reduce the smallest detectable difference from 9 to 6 mm, repeated measurement is necessary.

Adult↗
PubMed2000

Adherence to the guidelines of a regional formulary.

BACKGROUND: Pharmacotherapeutical guidelines, called formularies, have been developed to facilitate effective, efficient and cost-conscious prescribing. Monitoring adherence to such guidelines may be a reasonable way of assessing prescribing practices. OBJECTIVE: The aim of this study was to assess how strictly the GPs participating in our department's registration network adhere to the guidelines of the regional formulary, and which indications and drugs the GPs used. METHODS: This is a descriptive study, concerning 1000 consecutive prescriptions from each of the 17 participating GPs. The third edition of the Groningen formulary (GFIII), published in 1995, was used. If the drug prescribed was advised in the formulary, we considered it to be global adherence. If the indication was mentioned in the formulary, and the drug prescribed was advised for that indication in the formulary, it was considered to be specific adherence. Both the medications prescribed and the health problems registered by the GPs, but not mentioned in the GFIII, were analysed. RESULTS: The 17 000 prescriptions chosen for analysis formed approximately 25% of all prescriptions written by the GPs in 1 year. The indications for only 24 prescriptions (0. 14%) were missing. Among the 17 GPs, the number of different drugs prescribed varied between 167 and 219 per 1000 prescriptions. The global adherence varied from 76 to 89% among the GPs, and the specific adherence varied from 55 to 71%. Of the 17 000 prescriptions, 11 457 (67%) concerned indications mentioned in the GFIII. Prescriptions for indications not mentioned in the GFIII contained 4353 (78.5%) drugs advised in the formulary. Of the 251 medications mentioned in the GFIII, only 15 (6%) were not prescribed. DISCUSSION: The GPs in our study were neither representative, nor were they chosen at random. Their patient population was comparable in age, sex and insurance status. These findings are an example of what level of adherence is obtainable. The formulary covered approximately two-thirds of the indications registered by GPs, and did not contain many unnecessary medications (6%).

Adult↗
PubMed2000

The development of polypharmacy. A longitudinal study.

BACKGROUND: To date, only a few studies have been carried out on the development and progress of polypharmacy in relation to morbidity in general practices in The Netherlands. OBJECTIVE: The aim of this study was to investigate the relationship between an increase in long-term drug use and the incidence and severity of some chronic diseases, particularly in the elderly. METHODS: Data on medication and morbidity of 1544 elderly people were collected for the period 1994-1997 from three family practices in the medication and morbidity Registration Network of Groningen (RNG) in the northern part of The Netherlands. Polypharmacy is defined as the long-term simultaneous use of two or more drugs; long-term is defined as >240 days in a year. We looked for differences in incidences of some chronic diseases in those subgroups of the elderly in whom multiple long-term drug use respectively increased, stayed constant or did not exist. Polypharmacy at the end of the period was predicted using regression analysis. RESULTS: Polypharmacy occurred in 42% of the elderly at the end of 1997, with major polypharmacy (>5 drugs) in only 4%. The average number of drugs used long-term increased from 1.3 to 1.8 in 4 years. Predictors for the increase of polypharmacy were the number of drugs at the start, age, diabetes, coronary ischaemic diseases and use of medication without a clear indication (P < 0.005). The average number of diseases also increased, especially in the elderly who showed the greatest increase in long-term drug use; however, there was no significant difference from the groups with a slow or no increase in drug use. DISCUSSION: Polypharmacy showed a slow increase over 4 years: almost 20% of the elderly developed polypharmacy, i.e. going from no drugs or one drug to two or more drugs. Polypharmacy develops mainly in elderly patients who already use several drugs, who are known to suffer from cardiovascular diseases, diabetes or stomach symptoms, those who often take drugs (especially sedatives/hypnotics) without clear indication and those who develop hypertension or atrial fibrillation over time.

Aged↗
PubMed1999

Comparison of the effects of oral or subcutaneous carprofen or ketoprofen in rats undergoing laparotomy.

Rats undergoing laparotomy received either carprofen (5 mg/kg) or ketoprofen (5 mg/kg) administered orally in flavoured gelatin, or by subcutaneous injection. A control group that received no analgesic showed a significant (3 per cent) fall in bodyweight (P = 0.009) after laparotomy. This decrease was greater than that seen in the groups receiving carprofen (P = 0.006) or ketoprofen (P = 0.012) administered subcutaneously, which continued to gain weight following surgery. All animals showed a significant fall in food consumption but this decrease was greater in the jelly alone group (47 per cent) than in the group receiving carprofen (17 per cent) (P = 0.015) administered subcutaneously. A significant fall in water consumption occurred in the control group (40 per cent) and in animals that received oral carprofen (13 per cent) or Ketoprofen (22 per cent). No significant decrease was seen in groups receiving either carprofen or ketoprofen administered subcutaneously (P > 0.1). This study shows that a relatively simple surgical procedure results in a major reduction in food and water consumption in rats. This reduction can be minimised by the administration of ketoprofen or carprofen (5 mg/kg subcutaneously), but higher dose rates are required if these drugs are to be administered by the oral route.

Administration, Oral↗
PubMed1999

[Chronic polypharmacy in one-third of the elderly in family practice].

OBJECTIVE: Description of the extent and nature of polypharmacy in the elderly in general practice. DESIGN: Retrospective cross-sectional study. METHOD: Medication and morbidity data were collected over July-December 1994 on all 2197 patients > or = 65 years registered in 3 family practices connected with the Medication and Morbidity Registration Network Groningen, the Netherlands. Special attention was paid to the simultaneous use of > or = 2 drugs during > or = 120 days in the study period ('chronic use'). Three categories of polypharmacy were distinguished: mild (2-3 drugs), moderate (4-5) and extensive (> 5). RESULTS: Forty per cent of the study group were males; 54% were 65-74 years, 34% were 75-84 years and 12% were > or = 85 years. The mean number of drugs used was 3.9 per person (SD: 3.6), of which 1.4 (SD: 1.8) chronically. Polypharmacy occurred in 35%: mild in 23%, moderate in 8% and extensive in 4%. All occurred mostly in the group between 75 and 84 years old. Cardiovascular drugs, in particular diuretics, and psycholeptics were mostly prescribed concomitantly with each other and with other drugs. The prevalence of concomitant use of drugs with potential interactions was low (< 3%). The indications for psycholeptic drugs were quite often not clear. Congestive heart failure, chronic obstructive pulmonary disease (COPD)/asthma and diabetes mellitus were mainly responsible for extensive polypharmacy.

Aged↗
PubMed1999

Long distance telementoring. A novel tool for laparoscopy aboard the USS Abraham Lincoln.

BACKGROUND: As general surgeons perform a growing number of laparoscopic operations in increasingly specialized environments, the ability to obtain expert advice during procedures becomes more important. Technological advances in video and computer communications are enabling surgeons to procure expertise quickly and efficiently. In this article, we present laparoscopic procedures completed through an intercontinental telementoring system and the first telementored laparoscopic procedures performed aboard a naval vessel. METHODS: Video, voice, and data streams were linked between the USS Abraham Lincoln Aircraft Carrier Battlegroup cruising the Pacific Ocean and locations in Maryland and California, creating the Battlegroup Telemedicine (BGTM) system. Three modes of BGTM communication were used: intraship, ship to ship, and ship to shore. RESULTS: Five laparoscopic inguinal hernia repairs were completed aboard the Lincoln under telementoring guidance from land-based surgeons thousands of miles away. In addition, the BGTM system proved invaluable in obtaining timely expertise on a wide variety of surgical and medical problems that would otherwise have required a shore visit. CONCLUSIONS: Successful intercontinental laparoscopic telementoring aboard a naval vessel was accomplished using "off-the-shelf" components. In many instances, the high risk and cost of transporting patients to land-based facilities was averted because of the BGTM system. Also, the relationship between the on-site and telementoring surgeon was critical to the success of this experiment. Long-distance telementoring is an invaluable tool in providing instantly available expertise during laparoscopic procedures.

Adult↗
PubMed1999

Wilms' tumor: a 25-year review of the role of preoperative chemotherapy.

PURPOSE: This 25-year population based, single institution review was conducted to investigate the impact of preoperative chemotherapy on surgical and histological staging in patients with Wilms' tumors. RESULTS: Forty-nine patients under the age of 15 years were identified from case notes to have had histologically verified Wilms' tumors over the 25-year period from January 1972 to December 1996. Twenty-six patients were treated initially with preoperative chemotherapy, 23 with immediate surgery. Eleven had treatment randomized within the UKCCSG WT9101 trial (UKWT3), and the remainder received initial treatment according to unit policy. Surgical stages in the two groups (preoperative chemotherapy and immediate surgery) were respectively, stage 1:14(28.5%) and 11 (22.5%), stage II: one (2%) and eight (16.3%), stage III: 11 (22.5%) and four (8.2%). Seven patients had clinical stage IV disease at presentation. Histology results were favorable in 45 patients and unfavorable in four. All patients received chemotherapy during treatment, whereas 25 (51%) also received radiotherapy. No significant difference was evident in the two groups with respect to treatment-related morbidity. Five patients relapsed, three of whom died within the period of review, but a fourth has since died. CONCLUSIONS: This study suggests that the use of preoperative chemotherapy does not put the patient at increased risk of postoperative morbidity or reduced survival. The distribution of surgical stages suggests that limited tumor downstaging may have occurred as a result of preoperative chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Efficacy and safety profile of ketorolac 0.5% ophthalmic solution in the prevention of surgically induced miosis during cataract surgery.

This multicenter, double-masked, randomized, parallel study compared the efficacy and safety profile of ketorolac tromethamine 0.5% ophthalmic solution with that of its vehicle in the maintenance of pupillary mydriasis during cataract surgery. A total of 176 adult patients scheduled to undergo unilateral extracapsular cataract extraction and posterior-chamber intraocular lens implantation received either ketorolac tromethamine 0.5% (n = 89) or vehicle (n = 87), starting 2 hours before surgery. One drop of study medication was instilled every 30 minutes for a total of 4 drops. No epinephrine was used in the intraoperative irrigating solution. Pupil diameter was measured with a caliper at 3 time points during surgery. To ensure participant safety, biomicroscopy, ophthalmoscopy, intraocular pressure, adverse events, and preoperative and postoperative visual acuity and refractive error were also monitored. The mean change in horizontal and vertical pupil diameter from the time of the first incision to after cortical irrigation and aspiration was significantly less with active ketorolac than with vehicle (P < or = 0.014). Consequently, mean pupil diameter after cortical irrigation and aspiration was significantly greater with ketorolac than with vehicle (P < or = 0.030). No significant between-group differences were observed in the change in pupil diameter between the end of surgery and postoperative administration of a miotic agent, safety variables, or occurrence of adverse events. In this study, ketorolac tromethamine 0.5% ophthalmic solution provided effective and well-tolerated inhibition of surgically induced miosis during cataract surgery.

Aged↗
PubMed1999

Vascular risk factors and Alzheimer's disease.

OBJECTIVE: We aim to summarise the recent and accumulating epidemiological research which suggests that cardiovascular disease and vascular risk factors play an important role as risk factors for Alzheimer's disease (AD) in later life. METHOD: The epidemiological literature is summarised in considering the evidence for such an association, focusing on optimally designed population-based studies. Potential mechanisms of association are considered, drawing on relevant findings from neuroscience. RESULTS: Cardiovascular disease and vascular risk disorders appear to be important factors in the aetiology of AD. However, there is a paucity of prospective studies with an adequate duration of follow-up to investigate the apparent age- and time-dependent nature of these associations. CONCLUSIONS: Vascular disorders represent potentially preventable risk factors with an important population impact due to their high prevalence in developed countries. The concept of AD and vascular dementia as clearly distinguishable disorders clinically or aetiologically is becoming increasingly tenuous. A better understanding of the relationship between AD and vascular disorders will depend on a more flexible diagnostic and conceptual framework.

Aged↗
PubMed1999

Type 2 diabetes mellitus, cognitive impairment and dementia.

AIMS: We set out to examine the evidence for an association between cognitive impairment or dementia and the presence of Type 2 diabetes mellitus (DM). We also sought evidence of potential mechanisms for such an association. METHODS: A literature search of three databases was performed and the reference lists of the papers so identified were examined, using English language papers only. RESULTS: We found evidence of cross-sectional and prospective associations between Type 2 DM and cognitive impairment, probably both for memory and executive function. There is also evidence for an elevated risk of both vascular dementia and Alzheimer's disease in Type 2 DM albeit with strong interaction of other factors such as hypertension, dyslipidaemia and apolipoprotein E phenotype. Both vascular and non-vascular factors are likely to play a role in dementia in diabetes. CONCLUSIONS: Current classification structures for dementia may not be adequate in diabetes, where mixed pathogenesis is likely. Further research into the mechanisms of cognitive impairment in Type 2 DM may allow us to challenge the concept of dementia, at least in these patients, as an irremediable disease.

Case-Control Studies↗
PubMed1999

Promoting group empowerment and self-reliance through participatory research: a case study of people with physical disability.

PURPOSE: Despite the growing popularity of the empowerment construct among social scientists, relatively few empowerment studies involving groupwork with people with physical disabilities exist. This article accordingly describes and analyses the organic development of the empowerment process within a spinal cord injury self-help group, set against the backdrop of policy imperatives for disability in post-apartheid South Africa. METHOD: The treatise on the group empowerment process is located within the context of a group evaluation conducted within a participatory research framework. Key variables informing the research approach included: quality of participation, control over resources and decision-making, shift in critical consciousness and understanding, malleability of roles within the group and role of the health professional. RESULTS: Group members assumed ownership of group management and decision-making and shifted from a professionally-led to a peer-led self-help group. Group objectives changed from providing mutual support to community education and outreach activities. The role of the health professional shifted from group facilitator to invited consultant. CONCLUSIONS: This case study demonstrates how group participation, promoted by a critically informed therapeutic and research praxis, can unlock the inherent potential for self-reliance and empowerment of socially marginalized collectives. It offers important insights with regard to group process, participatory research and the role of the health professional in creating opportunities for empowerment and self-reliance of people with disability.

Adolescent↗
PubMed1999

Comparison of three commercial systems for identification of yeasts commonly isolated in the clinical microbiology laboratory.

We evaluated three commercial systems (RapID Yeast Plus System; Innovative Diagnostic Systems, Norcross, Ga.; API 20C Aux; bioMerieux-Vitek, Hazelwood, Mo.; and Vitek Yeast Biochemical Card, bioMerieux-Vitek) against an auxinographic and microscopic morphologic reference method for the ability to identify yeasts commonly isolated in our clinical microbiology laboratory. Two-hundred one yeast isolates were compared in the study. The RapID Yeast Plus System was significantly better than either API 20C Aux (193 versus 167 correct identifications; P < 0.0001) or the Vitek Yeast Biochemical Card (193 versus 173 correct identifications; P = 0.003) for obtaining correct identifications to the species level without additional testing. There was no significant difference between results obtained with API 20C Aux and the Vitek Yeast Biochemical Card system (P = 0.39). The API 20C Aux system did not correctly identify any of the Candida krusei isolates (n = 23) without supplemental testing and accounted for the major differences between the API 20C Aux and RapID Yeast Plus systems. Overall, the RapID Yeast Plus System was easy to use and is a good system for the routine identification of clinically relevant yeasts.

Candida↗