AMA council's ethics overwhelmed by public sentiment.
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Biomedical subjects
Publications and source records attributed to J Walters.
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In an effort to identify events initiating up-regulation of epidermal growth factor receptor after single and repeated radiation exposures, we investigated the role of epidermal growth factor receptor, a receptor protein tyrosine kinase, in radiation-induced signal transduction. Human malignant mammary, MCF-7, and squamous, A431, cells showed low baseline phospho-tyrosine levels of epidermal growth factor receptor, permitting reproducible dose-dependent stimulation of epidermal growth factor receptor autophosphorylation after exposure to epidermal growth factor. MCF-7 cells exhibited a mean 2.3-fold increase (95% confidence interval: 1.91, 2.65; P < 0.0001) in levels of epidermal growth factor phosphorylation in response to exposures of 2 Gy, which was substantially less than the epidermal growth factor receptor Y phosphorylation induced by epidermal growth factor. A quantitatively similar radiation response was seen in A431 cells. In the dose range of 1 to 4 Gy, no clear dose response was seen. There was a rapid induction of radiation-induced epidermal growth factor receptor Y phosphorylation, starting within 2 min, with maximum values between 0.5 and 5 min after radiation exposure followed by a slower decline to baseline levels after 20 min. The data presented identify the epidermal growth factor receptor protein tyrosine kinase associated with the plasma membrane as one target for ionizing radiation in the dose range used in radiotherapy.
OBJECTIVES: To assess views on use, maintenance and side-effects of the pneumatic tourniquet in the South African orthopaedic community. METHODS: A census-type questionnaire study was conducted of all 475 orthopaedic surgeons registered with the Orthopaedic Association of South Africa during 1993/94. The chi-square test was used to determine statistical significance between different groups of respondents. RESULTS: Seventy-seven per cent of the questionnaires were returned. Ninety-nine per cent of respondents used a pneumatic tourniquet. Eighty-four per cent believed that the tourniquet may damage underlying tissue both as a result of applied pressure effects and ischaemic consequences. Fifty-four per cent of respondents personally checked the calibration of the pneumatic tourniquet, although 76% of respondents believe that the apparatus needs to be checked at least once per month. More respondents who did not check the tourniquet apparatus than respondents who did check it believe that applied pressure does not cause tissue damage (P < 0.001), that the operating room technician or hospital engineer should be responsible for checking equipment (P < 0.001), and that equipment did not need to be checked more than once every 6 months (P < 0.001). CONCLUSIONS: Although most orthopaedic surgeons are aware of the pneumatic tourniquet's side-effects, a minority appear to be unaware of the hazards of excessive applied pressure alone or excessive applied pressure caused by use of faulty equipment. It needs to be emphasised to these surgeons that regular checking of the pneumatic tourniquet apparatus is necessary in order to prevent postoperative complications ascribed to use of the tourniquet.
There is limited information on the validity of bone mineral content measurement by dual energy X-ray absorptiometry (DXA BMC) for use in subjects with low body mass. We evaluated the accuracy and precision of DXA in piglets (body weight 886-5526 g, median 2096 g). Stepwise multiple regression analyses showed that ash weight is the major determinant of DXA BMC (adjusted r2 = 0.98, RMS residual = 3.61 g). The intercept was not significantly different from zero. DXA BMC measurements of other piglets under various clinical situations showed no significant effect from the use of cotton blanket, diaper, or positioning (prone, supine, lateral). In vivo replication of DXA BMC measurements of infants at a postnatal age of from 1-350 days showed a slope of 0.99 and high correlation coefficient (r2 = 0.99, RMS residual = 3.59 g). The intercept was not significantly different from zero, and the average coefficient of variation of duplicate DXA BMC in infants was 2.8%. We conclude that DXA BMC reliably but proportionately underestimates ash weight and is a highly precise method for measuring bone mineral status in young pediatric subjects.
Dual X-ray absorptiometry (DXA) measurements have been shown to provide useful information on bone mineral status in young pediatric subjects. The purpose of this study was to challenge this system under various conditions to determine the clinical and experimental parameters that may be encountered which could interfere with DXA-based bone mineral content (BMC) and bone mineral density (BMD) measurements. Variations in data acquisition, including the covering of step phantom (external calibration standard) with a cotton blanket or partial exclusion of step phantom in the scan field, tissue freezing, or the presence of small nonmetallic objects, did not significantly alter DXA BMC or BMD measurements. By contrast, the presence of movement artifact, radiographic contrast media, and nonmetallic orthopedic casts significantly interfered with DXA BMC and BMC measurements. Variability in operator-dependent analysis of DXA scans occurred with regional analysis of whole body scans for DXA BMC and BMD measurements (average coefficient of variation was 2.9% and 1%, respectively, depending on the region analyzed) but did not affect the total (whole body) result. A minor adjustment in the manual delineation of the step phantom during data analysis may result in almost a 30% difference in DXA BMC and BMD. We conclude that movement artifact, radiographic contrast media, nonmetallic or orthopedic cast, and variations in operator-dependent data analysis may interfere with DXA BMC and BMD measurement in young pediatric subjects. Therefore, appropriate care should be taken to reduce or eliminate such interference.
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Sixteen 17-year-old kibbutz members, seven of them smokers, and nine nonsmokers of hashish, assessed the probability that a young person of similar background would use drugs. Two sources of information were manipulated bifactorially: personal predisposition (curiosity, risk-taking, and existential meaning) and the level of group pressure to smoke hashish. It was found that hashish smokers assigned meaningful importance to a combined influence of the two factors, while the nonsmokers considered only group pressure to be important. A tool based on the measurement method examined in this study is proposed for predicting the probability of drug use among adolescents.
Forty-four adult patients with acute asthma were treated with albuterol at a rate of 15 mg/h over 2 h. Analysis of covariance showed a significantly higher baseline adjusted mean for both percent predicted forced expiratory volume in 1 s (PFEV1) (p = 0.045) and percent predicted forced vital capacity (PFVC) (p = 0.022) at 50 and 110 min for the patients who reported triamcinolone use. Although heart rates decreased overall during the first hour of albuterol treatment, a rise in mean heart rate occurred during the second hour of treatment only in patients reporting triamcinolone use (p = 0.005). After accounting for the effects of parenteral corticosteroids, the effect of reported triamcinolone use remained significant. These data suggest that use of inhaled corticosteroids in this context may be associated with enhanced local and systemic beta-responsiveness, and if a causal relationship could be confirmed, this may constitute yet another advantage of early inhaled corticosteroid treatment in asthma. These data also suggest that chronotropic effects of high-dose albuterol should be monitored in patients using inhaled triamcinolone.
STUDY OBJECTIVES: To compare bronchodilation, chronotropic effects, and side effects of the same dose of nebulized albuterol when given by either intermittent or continuous administration. DESIGN: A randomized assignment of patients to one of the two methods of albuterol nebulization. SETTING: Adult emergency department in an urban public hospital. TYPE OF PARTICIPANTS: Adult patients with acute exacerbations of asthma. INTERVENTIONS: Administration of 30 mg albuterol given over 110 minutes by either continuous or intermittent aerosolization. MEASUREMENTS: FEV1, forced vital capacity, heart rate, and systolic and diastolic blood pressures were measured immediately before treatment and then hourly for two hours. Side effects, symptoms, subsequent admission, and discharge also were noted. MAIN RESULTS: An overall significant decrease in heart rate was observed, indicating the lack of significant chronotropic effects with this dose of albuterol. Both treatments resulted in significant spirometric improvement without a significant treatment difference for the entire group. A difference, however, was found in the relative rates of FEV1 improvement with the two treatments depending on whether patients had an initial FEV1 less than or more than 50% predicted (P = .05). A secondary analysis on patients with an initial FEV1 less than percent predicted demonstrated a higher rate of percent predicted FEV1 increase with the continuously nebulized albuterol group (P = .03). CONCLUSION: This study demonstrates that albuterol can be given safely at this dose by either intermittent or continuous nebulization. Future studies should examine whether continuous nebulization has a reproducible advantage over intermittent nebulization in patients with more severe obstruction.
1. Antibiotics are important agents for the treatment of infections. 2. They are special chemicals produced by a few species of microorganisms which inhibit the growth of other micro-organisms. 3. They inhibit growth by attacking one of five sensitive sites. 4. A selection of antibiotics attacking the protein synthesis mechanism are identified and their modes of action described.
This paper analyses data for 1990 culled from the medical records of the Queen Elizabeth Hospital, Barbados and examines the use of inpatient and emergency services by visitors to Barbados. The 473 visitors admitted represented 2.1% of all admissions. The records of 425 contained information on country of origin: 145 were from non-Caribbean and 280 from Caribbean countries. The distribution by country of non-Caribbean visitors was the same as that of regular tourist arrivals--the majority came from the USA. Canada and the UK. Caribbean visitors represented 14.4% of the tourists, but accounted for 65.9% of visitor admissions. Non-Caribbean visitors were 85.6% of tourists, but 34.1% of admissions. Young patients predominated among Caribbean, and older patients among non-Caribbean. Accidents, cardiovascular disease, alcohol-related illnesses and near drowning were commoner in the non-Caribbean visitors, while cancer and obstetrical/gynaecological problems were commoner in Caribbean visitors. Seven per cent of visitor admissions went to the Intensive Care Unit as against 0.15% of other patients. The average hospital stay of visitors was 11.7 days compared with 7.0 days for Barbadians. There were 898 visitors treated in the Accident and Emergency Department and the commonest problems were lacerations, abrasions and infections. The UK provided most of these patients. These data show that there is appreciable visitor use of the public health services. Non-Caribbean visitors use them because they fall ill on holiday, but many Caribbean visitors may come specifically for health care. The cost to the Barbadian health service is not insignificant: at the 1990 estimated bed-day cost of Bds$250, it represents a cost of Bds$1.1 million per annum to the Government for inpatient services alone, or 2% of total hospital costs.
Both insulin secretion and insulin sensitivity are important in the development of diabetes but current methods used for their measurements are complex and cannot be used for epidemiological surveys. This study describes a simplified approach for the estimation of first phase insulin release and insulin sensitivity from a standard 40-min intravenous glucose tolerance test (IVGTT), and compares these parameter estimations with the sophisticated minimal model analysis of a frequently sampled 3-h IVGTT and the euglycaemic clamp technique. For the simplified IVGTT, first phase insulin release was measured as the insulin area above basal post glucose load unit-1 incremental change (i.e. peak rise) in plasma glucose over 0-10 min, and insulin sensitivity as a rate of glucose disappearance (Kg) unit-1 insulin increase above basal from 0-40 min post-glucose load in 18 subjects who were studied twice, either basally or in a perturbed pathophysiological state (i.e. pre- and post-ultramarathon race, n = 5; pre- and post-20 h pulsatile hyperinsulinaemia, n = 8; pre- and post-thyrotoxic state, n = 5). A further 12 subjects were compared by IVGTT, and glucose clamp. In addition, seven dogs were studied three times by IVGTT during normal saline infusion and after short-term (1/2 hour) or long-term (72 hour) adrenaline infusions. First phase insulin release and insulin sensitivity estimated from the simplified IVGTT as calculated by the two methods correlated closely (rs = 0.89 and rs = 0.87, respectively), although less precisely in markedly insulin-resistant subjects and the slopes and y intercepts of the linear regression lines were similar in the basal and perturbed states.(ABSTRACT TRUNCATED AT 250 WORDS)
The effects of nasal continuous positive airway pressure (CPAP) were examined during cardiac catheterization in 22 patients with congestive heart failure (CHF). CPAP was applied at a level of 5 cm H2O pressure. Hemodynamic measurements were made at baseline and while on CPAP. We hypothesized that patients with high left ventricular (LV) diastolic pressures would experience an increase in cardiac index (CI). To test this hypothesis, patients were divided into two groups based on their baseline pulmonary capillary wedge pressure (PCWP): one group of 11 whose PCWP was greater than or equal to 12 mm Hg (high-PCWP group) and a second group of 11 whose PCWP was less than 12 mm Hg (low-PCWP group). Among the high-PCWP group (mean PCWP +/- SEM = 19.0 +/- 2.7 mm Hg), CI rose significantly while on CPAP (from 2.48 +/- 0.26 to 2.82 +/- 0.26 L/min/m2, p less than 0.01). Stroke volume index (SVI) also rose significantly (from 52.6 +/- 7.0 to 64.1 +/- 8.0 ml/m2, p less than 0.001). In contrast, among the low-PCWP group (PCWP = 8.3 +/- 0.6 mm Hg), CI decreased significantly while on CPAP (from 3.14 +/- 0.44 to 2.89 +/- 0.62 ml/m2, p less than 0.025). SVI fell but not significantly while on CPAP (from 75.5 +/- 8.4 to 74.2 +/- 8.5 ml/m2). Multiple stepwise linear regression analysis revealed that the only significant correlate of the magnitude of change in CI in response to CPAP was baseline PCWP (r = 0.50, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
Samples of alcohol-dependent-only subjects (n = 164), cocaine-dependent-only subjects (n = 63), and subjects dependent on multiple substances, including alcohol and cocaine (n = 103), were administered the Millon Clinical Multiaxial Inventory (MCMI) as part of a routine clinical evaluation. The alcohol-only group was older (M = 38.7 years) and had a higher percentage of White subjects than other groups. The multiple-use (60%) group also had a higher percentage of White subjects than the cocaine only group (38%) and a higher percentage of male subjects (81%) than the alcohol-only group (67%). Although the MCMI characteristics of each diagnostic group paralleled previous findings, few MCMI differences were found after controlling for age, sex, and race effects. The implications of these results for treatment development are discussed.
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Recent cluster analytic research with alcoholic inpatients has demonstrated the existence of several Millon Clinical Multiaxial Inventory (MCMI) clusters that appear to be consistent across different subject samples. The validity of these data would be strengthened by a statistical demonstration of the similarity of attained clusters across studies--a demonstration of concordance of subject classification across different clustering techniques on the same data set- and the inclusion of external, independent measures against which to evaluate the predictive validity of the cluster typology. We found a high level of concordance in subject classification across different clustering methods on the same data set and a high level of agreement with cluster typologies attained in previous studies. Subsequent multivariate analyses employing independent scales measuring various aspects of alcohol use confirmed differences among cluster members on perceived benefits of alcohol use and deleterious effects of alcohol use. The prominent differences in alcohol use along with a rationale for their development are discussed.