Living-related donation: do professional opinions influence parent decision making?
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Attitude of Health Personnel↗
Biomedical subjects
M A Lewis
Publications and source records attributed to M A Lewis.
Deoxyribonucleic acid typing methods for medically important microorganisms.
The ability to type microorganisms to a sub-species level plays an essential role in the diagnosis, treatment and control of human infection. Traditionally, differentiation of microorganisms has involved analysis of phenotypic markers. However, these methods are not universally applicable to all microorganisms, and results may be influenced by environmental factors. Recent developments in DNA analysis, together with the limitations of phenotypic methods, have resulted in an increasing use of procedures based on DNA analysis for the typing of clinically important microorganisms. The aim of this review is to provide an overview of the advantages and disadvantages of the genetic typing techniques currently available.
Bacterial Typing Techniques↗
Oral contraception was not associated with venous thromboembolic disease in recent study.
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Adolescent↗
Measurement of heat conduction through stacked screens.
This paper describes the experimental apparatus for the measurement of heat conduction through stacked screens as well as some experimental results taken with the apparatus. Screens are stacked in a fiberglass-epoxy cylinder, which is 24.4 mm in diameter and 55 mm in length. The cold end of the stacked screens is cooled by a Gifford-McMahon (GM) cryocooler at cryogenic temperature, and the hot end is maintained at room temperature. Heat conduction through the screens is determined from the temperature gradient in a calibrated heat flow sensor mounted between the cold end of the stacked screens and the GM cryocooler. The samples used for these experiments consisted of 400-mesh stainless steel screens, 400-mesh phosphor bronze screens, and two different porosities of 325-mesh stainless steel screens. The wire diameter of the 400-mesh stainless steel and phosphor bronze screens was 25.4 micrometers and the 325-mesh stainless steel screen wire diameters were 22.9 micrometers and 27.9 micrometers. Standard porosity values were used for the experimental data with additional porosity values used on selected experiments. The experimental results showed that the helium gas between each screen enhanced the heat conduction through the stacked screens by several orders of magnitude compared to that in vacuum. The conduction degradation factor is the ratio of actual heat conduction to the heat conduction where the regenerator material is assumed to be a solid rod of the same cross sectional area as the metal fraction of the screen. This factor was about 0.1 for the stainless steel and 0.022 for the phosphor bronze, and almost constant for the temperature range of 40 to 80 K at the cold end.
Alloys↗
The epidemiology of oral contraceptive use: a critical review of the studies on oral contraceptives and the health of young women.
Recent observational studies show a slightly increased risk of venous thromboembolism among users of newer combined oral contraceptives with odds ratios between 0.8 and 2.3 when compared with users of older oral contraceptives. The controversy regarding the newer oral contraceptives is reviewed by analyzing the recent studies with epidemiologic methods. Key studies on venous thromboembolism may be subject to bias related to prescribing criteria, diagnostics, hospital referral, cohort effects, and residual confounding, resulting in an overestimate of the risk of venous thromboembolism associated with the newer oral contraceptives. The studies on stroke showed no difference between newer and older oral contraceptives, and studies on myocardial infarction show that newer oral contraceptives carry no risk of this event. Newer-generation oral contraceptives are unlikely to constitute a significant hazard to the user population with regard to venous thromboembolism. The results for other disease entities also need to be taken into account when the results on venous thromboembolism are assessed on a population basis.
Adolescent↗
Thromboembolic stroke in young women. A European case-control study on oral contraceptives. Transnational Research Group on Oral Contraceptives and the Health of Young Women.
A matched case-control study was performed between 1993 and 1996 in 16 centers in the United Kingdom, Germany, France, Switzerland, and Austria. The objective was to determine the influence of oral contraceptives (OC), particularly those containing modern progestins, on the risk for ischemic stroke in women aged 16-44 years. A total of 220 women who had had an incident ischemic stroke and were compared with 775 control subjects who were unaffected by stroke. At least one hospital and one community control subject per patient was matched and interviewed with the corresponding patient for 5-year age band and for area of residence. Crude odds ratios (95% confidence intervals [CI]) for ischemic stroke were as follows. For current use of any OC versus no use 2.3 (1.7-3.2), the adjusted odds ratio (OR) 3.6 (2.4-5.4). The OC associated risk was higher for first generation than for second or third generation OC. The risk estimates for patients versus community control subjects were always lower than for hospital control subjects. No major regional difference of the risk estimates was found. Compared with nonusers of OC without hypertension, women with hypertension who used OC had an almost 10-fold increased risk. However, OC users who had had a blood pressure check before OC prescription had a lower risk than did those without such a check. Smoking > 10 cigarettes/day is associated with higher risk of stroke, particularly for OC users. No significant effect was found for duration of OC use. We conclude that although there is a small relative risk of occlusive stroke for healthy women currently using OC, the attributable risk is very small because the incidence in this age group is very low. The small increase in risk of OC use may be further reduced by preventive efforts for cardiovascular risk factors, particularly hypertension and smoking.
Adolescent↗
The risks of venous thromboembolic disease among German women using oral contraceptives: a database study.
This study investigated the risk of venous thromboembolic disease (VTE) between second and third generation combined oral contraceptives, using the German MediPlus database of patient records. Women studied included 42 patients between the ages of 18 and 49 years, with a diagnosis of VTE treated with an anticoagulant, who were exposed to an oral contraceptive (OC). Four controls per patient (168), matched by year of birth and exposure to an OC on the even day, were identified. More women were users of second generation than third generation OC, and none were using progestogen-only pills. There was no significant difference between patients and control subjects with respect to the type of OC used on the event day (unadjusted odds ratio for third versus second generation users was 0.77; 95% confidence interval [CI] 0.38-1.57). There was no significant age difference between second and third generation users among patients or control subjects. Between January 1 and the event date, there was no significant difference between the patients and control subjects in terms of the number of oral contraceptive prescriptions, number of consultations for psychotherapeutic complaints, or mixed physical and psychotherapeutic consultations; however, patients did demonstrate significantly more consultations for purely physical complaints compared with control subjects (p < 0.0001). There were no significant consultation differences between patients with pulmonary emboli (n = 6) and other VTE patients (n = 36). No significant differences with respect to VTE risk between users of second and third generation oral contraceptives were found in this study. Consultations (physical) for patients were higher than for control subjects before the VTE event. If consultation rate relates to the general health status of a person, this might indicate that VTE risk is higher among women of poorer health, but that this is not related to the type of progestogen in the oral contraceptive that they use.
Adolescent↗
An examination of the role of learning environments in the construction of nursing identity.
The interplay between the development of a nurse's identity within the world of nursing, and the construction of relevant nursing concepts is by necessity a difficult and complex one. It is in part grounded in the theories of social interaction, concept formation, and relevant peripheral participation in the workplace, all of which can be related to the nursing role. These issues are considered here primarily from the sociocultural viewpoint of Vygotsky, bringing together the important role of significant participants in the nurse's learning experiences, predominantly peers, and examining briefly the effects of such a viewpoint in relation to nursing education. How best nursing knowledge may be structured to optimize the learner's educational experiences, and how best the learning environment of the student may be utilized to maximum educational benefit still remain complex questions. With moves towards more competence-based learning such interactions may be crucial to our understanding of the complexities of learning in what are essentially very practical-based environments, and at the same time allow us to acknowledge the important mechanisms involved in concept acquisition and transferability, a notion central to lifelong learning.
Education, Nursing, Baccalaureate↗
Ethical challenges in treating mother and fetus when cancer complicates pregnancy.
This article evaluates the complicated scenario for physicians when they must advise pregnant oncology patients and their families. Included in this discussion are a review of literature that addresses both maternal and fetal rights and an analysis of metaphysical considerations unique to this situation. Additionally, there is a presentation of philosophical ideations, including an introduction to the ethical principles of autonomy, beneficence, and authenticity, which are offered in an attempt to increase the physician's comfort level with this very difficult task.
Adult↗
Myocardial infarction and stroke in young women: what is the impact of oral contraceptives?
Recent discussions have centered on the small apparent risk increase for venous thromboembolism found with newer oral contraceptives (third-generation oral contraceptives containing the progestins desogestrel and gestodene) compared with older oral contraceptives (second-generation). This article reviews the studies addressing the association between oral contraceptive use and thromboembolic conditions affecting the arterial system, ischemic stroke, and myocardial infarction. Differences are found between a US database study, which showed no risk of ischemic stroke or myocardial infarction associated with low-dose oral contraceptive use, and the European studies, which showed oral contraceptive use in general to be associated with increased risks of ischemic stroke and myocardial infarction. The European studies showed no difference between oral contraceptive generations with respect to the occurrence of ischemic stroke; however, the risk of myocardial infarction associated with oral contraceptive use was consistently lower for third- than for second-generation oral contraceptives. Although there seems to be no differential risk of ischemic stroke associated with oral contraceptive generations, third-generation oral contraceptives appear to be consistently associated with no excess risk of myocardial infarction. In all instances, however, cardiovascular risk factors other than oral contraceptive use play the predominant role in the occurrence of ischemic stroke and myocardial infarction.
Adolescent↗
SPECT electronic collimation resolution enhancement using chi-square minimization.
An electronic collimation technique is developed which utilizes the chi-square goodness-of-fit measure to filter scattered gammas incident upon a medical imaging detector. In this data mining technique, Compton kinematic expressions are used as the chi-square fitting templates for measured energy-deposition data involving multiple-interaction scatter sequences. Fit optimization is conducted using the Davidon variable metric minimization algorithm to simultaneously determine the best-fit gamma scatter angles and their associated uncertainties, with the uncertainty associated with the first scatter angle corresponding to the angular resolution precision for the source. The methodology requires no knowledge of materials and geometry. This pattern recognition application enhances the ability to select those gammas that will provide the best resolution for input to reconstruction software. Illustrative computational results are presented for a conceptual truncated-ellipsoid polystyrene position-sensitive fibre head-detector Monte Carlo model using a triple Compton scatter gamma sequence assessment for a 99mTc point source. A filtration rate of 94.3% is obtained, resulting in an estimated sensitivity approximately three orders of magnitude greater than a high-resolution mechanically collimated device. The technique improves the nominal single-scatter angular resolution by up to approximately 24 per cent as compared with the conventional analytic electronic collimation measure.
Algorithms↗
Analytic treatment of resolution precision in electronically collimated SPECT imaging involving multiple-interaction gamma rays.
The widely applied single-interaction analytic expression characterizing the energy resolution component of the angular resolution precision for an electronically collimated point source is extended to include multiple-interaction Compton scatter sequences as well as sequences terminated by photoelectric absorption. The analytic formulation is developed using the statistical variance of the mean for components comprising composite, multivariate resolution precision estimators. It is demonstrated that enhanced resolution precision in the incident interaction scatter angle is attained when use is made of information from multiple interactions. An improvement in the resolution precision of up to approximately 40% is observed for triple Compton scatter. Comparison of the analytic estimates with Monte Carlo/chi-square results shows good agreement.
Chi-Square Distribution↗
Atrial fibrillation and anticoagulation in patients with permanent pacemakers: implications for stroke prevention.
Several large prospective randomized trials have demonstrated that anticoagulation with warfarin reduces the risk of thromboembolic stroke in high risk patients with chronic AF by approximately 70%. Large numbers of patients with permanent pacemakers have AF, and anticoagulation rates in this population have not been described. In a prospective analysis of 110 consecutive patients attending the pacemaker clinic of a large university hospital we assessed the number of patients with AF and the proportion of these patients who were receiving anticoagulation to prevent thromboembolic stroke. Where necessary, temporary pacemaker reprogramming to low ventricular rates was utilized to facilitate the diagnosis of AF. Fifty-three of the 110 patients (48%) were diagnosed with AF, all of whom (100%) had accepted high risk factors for thromboembolic stroke. Only eight of the 53 (15%) had been anticoagulated with warfarin. Thirty-six of the 53 patients (68%) diagnosed with AF had no prior documented diagnosis of chronic AF, and the majority had no symptoms suggesting AF. A single lead II ECG was insufficient in 67 of the 110 patients (61%) to diagnose the underlying atrial rhythm; the remainder required 12-lead ECGs or temporary pacemaker reprogramming to low ventricular rates to diagnose the underlying atrial rhythm. AF is common in patients with permanent pacemakers. It is commonly asymptomatic, and anticoagulation is markedly underutilized in reducing stroke risk in these patients. Attention to the possibility of AF in paced patients should allow prompt diagnosis and allow both the initiation of anticoagulation in order to reduce thromboembolic stroke risk and consideration for cardioversion of AF to sinus rhythm.
Aged↗
Immunocytochemical detection of Candida albicans in formalin fixed, paraffin embedded material.
AIM: To assess the ability of the commercially available monoclonal antibody 1B12 (BioGenex, San Ramon, USA) to identify C albicans in formalin fixed, paraffin wax embedded material (FFPE). METHODS: Broth cultures of 20 strains of seven Candida species were resuspended in 4% agarose blocks, fixed in formalin for 24 hours, and embedded in paraffin wax. In addition, 16 blocks of FFPE tissue known to contain periodic acid-Schiff positive fungal hyphae were examined. Antigen retrieval involved microwave treatment of specimens in citrate buffer (0.01 M; pH 6.5) before addition of 1B12 antibody for 24 hours. Bound antibody was subsequently detected using a biotinylated link antibody and a peroxidase conjugated streptavidin. RESULTS: Only C albicans strains were 1B12 positive in the agarose blocks. All FFPE tissue blocks were found to contain 1B12 positive hyphal structures, indicating the presence of C albicans. CONCLUSIONS: The ability to identify candida organisms penetrating the lesional tissue in cases of chronic hyperplastic candidosis will help to clarify the role of individual Candida spp in this important form of oral candidosis.
Antibodies, Monoclonal↗
A novel technique for assessment of adherence of Candida albicans to solid surfaces.
A novel approach for the assessment of adherence of Candida albicans to translucent acrylic material is described. The method uses the inverted microscope to visualise yeast adhering to acrylic surfaces while the test material remains immersed in buffer. Adherent cells were not subjected to surface tension forces that can occur during drying processes, so that an even distribution of yeast with no aggregation occurred. The process of counting attached yeast was subsequently performed without difficulty. From the 11 C albicans isolates examined, two groups were evident with respect to acrylic adherence: one group of four isolates with an adherence level of 400 yeast/mm2 acrylic, and one group of seven isolates with adherence levels of 1000 yeast/mm2 acrylic.
Acrylic Resins↗
Differences between child and parent reports of symptoms among Latino children with asthma.
OBJECTIVES: To determine, in a population of predominantly Latino children with asthma 6 to 18 years old, whether parent and child reports of asthma symptoms with exercise differ and to evaluate the validity of child and parent reports of symptoms. DESIGN: Data obtained from child and parent interviews; pulmonary function tests (forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow25-75, peak expiratory flow), and observation of symptoms after exercise. SETTING: Three summer camps for minority children with asthma in Los Angeles County. PARTICIPANTS: A total of 97 children with asthma (78% Latino, 12% non-Latino White, 9% Other; 6 to 18 years of age) and their parents. INTERVENTION(S): None. PRIMARY OUTCOME MEASURES: Child and parent reports of cough and wheezing with exercise and pulmonary function tests before and after exercise. While at camp, children underwent spirometry after completing the self-administered survey. The pulmonary function tests were conducted and interpreted according to the pediatric specifications for spirometry, and results >80% of predicted, adjusted for gender, age, height, and race, were considered normal. Six peak expiratory flow rates (PEFR) by peak flow meter also were recorded by trained research assistants immediately before spirometry, and values >80% of predicted based on height were considered normal. To observe child symptoms with exercise, children participated in a relay running race of 200 feet followed by a swimming race of 300 feet. Research assistants measured heart rate and 6 PEFRs using ASSESS portable peak flow meters immediately before and after each exercise. A positive exercise challenge was defined as a 15% reduction in mean PEFR and/or observed asthma symptoms (cough, wheezing, chest pain, asthma attack). RESULTS: Of the children, 18% reported never having a cough when they exercised, 46% reported having it occasionally when they exercised, and 36% reported having it quite often or always when they exercised. For wheezing, 20% of children reported never having wheezing when they exercised, 35% having it occasionally when they exercised, and 45% having it quite often or always when they exercised. Parents reported fewer symptoms than did their children. Of the parents, 34% reported that their children did not have cough with exercise, 37% reported few to some days, and 29% reported most days or every day. Forty-seven percent of parents reported that their child did not wheeze with exercise in the last 2 months, 35% reported wheezing on a few days to some days, and 17% reported wheezing most days to every day. Parent and child reports of cough or wheezing after exercise correlated mildly with each other (parent/child cough r = 0. 23; kappa = 0.03; parent/child wheezing r = 0.21; kappa = 0.14). Children were more likely to report cough: 59 of 71 (83%) of children versus 44 of 71 (62%) of parents. The 22 children who reported cough when their parents did not account for most of the disagreement between parents and children. Children were more likely than were their parents to report wheezing; 55 of 69 (80%) children versus 36 of 69 (52%) parents reported that the child wheezed. The 24 children who reported wheezing when their parents did not account for most of the disagreement between parents and children. Forty-seven percent of the children had a value <80% of predicted for at least one of the four spirometry tests; 29% of mean baseline PEFRs were <80% of predicted. Overall, 86% of the children met one or more of the following: any percent of predicted pulmonary function tests <80% or any symptom or PEFR reduction of 15% after exercise, or other occurrence of nonexercise symptoms during camp. Almost all child reports of cough and wheezing correlated significantly with the criterion validity criteria. For example, child reports of wheezing were, as expected, correlated negatively with the percent of predicted FEV1 (r = -0.28) and correlated positive
Adolescent↗
Case-control study of oral contraceptives and risk of thromboembolic stroke: results from International Study on Oral Contraceptives and Health of Young Women.
OBJECTIVE: To determine the influence of oral contraceptives (particularly those containing modern progestins) on the risk for ischaemic stroke in women aged 16-44 years. DESIGN: Matched case-control study. SETTING: 16 Centres in the United Kingdom, Germany, France, Switzerland, and Austria. SUBJECTS: Cases were 220 women aged 16-44 who had an incident ischaemic stroke. Controls were 775 women (at least one hospital and one community control per case) unaffected by stroke who were matched with the corresponding case for 5 year age band and for hospital or community setting. Information on exposure and confounding variables were collected in a face to face interview. MAIN OUTCOME MEASURES: Odds ratios derived with stratified analysis and unconditional logistic regression to adjust for potential confounding. RESULTS: Adjusted odds ratios (95% confidence intervals) for ischaemic stroke (unmatched analysis) were 4.4 (2.0 to 9.9), 3.4 (2.1 to 5.5), and 3.9 (2.3 to 6.6) for current use of first, second, and third generation oral contraceptives, respectively. The risk ratio for third versus second generation was 1.1 (0.7 to 2.0) and was similar in the United Kingdom and other European countries. The risk estimates were lower if blood pressure was checked before prescription. CONCLUSION: Although there is a small relative risk of occlusive stroke for women of reproductive age who currently use oral contraceptives, the attributable risk is very small because the incidence in this age range is very low. There is no difference between the risk of oral contraceptives of the third and second generation; only first generation oral contraceptives seem to be associated with a higher risk. This small increase in risk may be further reduced by efforts to control cardiovascular risk factors, particularly high blood pressure.
Adolescent↗
Lowered risk of dying of heart attack with third generation pill may offset risk of dying of thromboembolism.
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Adolescent↗