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Biomedical subjects

G Norman

Publications and source records attributed to G Norman.

At least 73 records · Page 4Linked to original sources
PubMed1991

Observer variation in detecting the radiologic features associated with bronchiolitis.

Chest radiographs are commonly obtained to assess children for bronchiolitis, both to corroborate the diagnosis and to exclude other diagnostic possibilities. Their utility in this setting has not previously been examined. Using a blinded, randomized study design, we examined the interobserver and intraobserver variation in the detection of the radiologic features of bronchiolitis from the chest radiograph using "weighted kappa" statistics. This observer variation was compared with that found by other authors for other diagnoses. We also determined the reported presence of these radiologic features in radiographs from patients with bronchiolitis as compared with normal controls. Our study showed acceptable interobserver (kappa = 0.40-0.66) and intraobserver agreement (kappa = 0.50-0.78) on the radiologic features of bronchiolitis relative to other diagnoses. We demonstrated a higher reported presence of these accepted radiologic features in patients with bronchiolitis as compared to controls. Although kappa statistics are widely used in studies of observer variation, "weighted kappa" has received little attention in the radiologic literature. This statistical analysis allows observers to equivocate on the presence or absence of a feature and therefore allows the format of observer variation studies to simulate more closely the normal clinical setting.

Bronchiolitis, Viral↗
PubMed1991

An insular outbreak of dengue fever in a rural south Indian village.

In mid 1990, an epidemic of fever affected a single village in Kaniyambadi Block, South India. The illness was characterized by a fever of approximately five days duration, accompanied by headache, chills, sweating and muscle pain. The overall attack rate was 22.5 per cent. The attack rate was uniform across the various age groups and between the sexes. Testing of the acute and convalescent serum samples obtained from cases showed a serological response to dengue virus. The Aedes house index in the village was found to be 36 per cent with toilets serving as active breeding sites. Adjacent villages studied showed similarly high rates of Aedes prevalence, although no cases of the same fever were seen. Since previous exposure to dengue increases the risk for epidemics of dengue hemorrhagic fever and dengue shock syndrome, health education on methods of Aedes control is continuing.

Adolescent↗
PubMed1990

Altered platelet calcium metabolism as an early predictor of increased peripheral vascular resistance and preeclampsia in urban black women.

BACKGROUND: Although preeclampsia is an important and relatively common medical problem, its pathophysiology remains unresolved and the search for a biochemical marker that precedes the hemodynamic abnormalities of preeclampsia continues. We designed a study to investigate the hemodynamic changes that characterize preeclampsia and to evaluate the metabolism of platelet intracellular calcium as a possible predictor of the development of preeclampsia. METHODS: Hemodynamic measurements and spectrofluorometric determinations of the levels of intracellular calcium in platelets in the basal state and after stimulation with an agonist were performed in 48 nulliparous black women during each trimester of pregnancy. The data on the 14 women (29 percent) in whom preeclampsia developed were then compared with the data on the other 34, who served as normotensive controls. RESULTS: There was no significant difference between the two groups in the basal levels of intracellular calcium at any time. In contrast, the levels measured after arginine vasopressin was administered during the first trimester indicated an exaggerated response in the group with preeclampsia as compared with the control group (1494 +/- 388 [+/- SEM] percent vs. 545 +/- 55 percent of base line; P less than 0.0002), which was sustained through the second and third trimesters. All but three of the women with preeclampsia had responses higher than the highest response among the controls. Platelet intracellular calcium responses to arginine vasopressin during the first trimester were a sensitive predictor of the subsequent development of preeclampsia (P less than 0.00009). Although vascular resistance was similar in the two groups during the first trimester, it subsequently decreased in the control group (P less than 0.02) but not in the group with preeclampsia. CONCLUSIONS: Our findings indicate that preeclampsia is characterized by the absence of the normal pregnancy-related decrease in vascular resistance, which is preceded in most instances by an exaggerated response of platelet intracellular calcium to arginine vasopressin early in pregnancy. We therefore propose that an increase in the sensitivity of platelet calcium to arginine vasopressin can be used as an early predictor of subsequent preeclampsia.

Adolescent↗
PubMed1990

Evaluation of potential early markers of chorioamnionitis associated with preterm premature ruptured membranes.

Optimal expectant management of preterm premature rupture of membranes (PROM) requires the early detection of chorioamnionitis. To date, however, no universally sensitive and specific marker for chorioamnionitis has been identified. Recently, the serial determination of plasma fibronectin, antithrombin, and prekallikrein has been reported to facilitate the early detection of sepsis in critically ill neonates and adult surgical patients. A cross-sectional study was undertaken to determine if plasma levels of these markers change significantly in patients with overt chorioamnionitis following expectant management of preterm PROM. Plasma levels of fibronectin and prekallikrein were not significantly different between the study (30 patients with overt chorioamnionitis following preterm PROM) and control (30 undelivered patients without antenatal complication matched for gestational age) groups. Antithrombin levels were significantly lower in the study group (p less than 0.05), but the magnitude of the difference (102% versus 94%) is not likely to be of clinical significance. We conclude that determination of plasma levels of fibronectin, prekallikrein, and antithrombin is not likely to aid in the early detection of chorioamnionitis in the setting of preterm (PROM).

Antithrombins↗
PubMed1990

Reliability and learning from the objective structured clinical examination.

The difficulties in measurement of the clinical performance of students in the health professions are well known by educators. One innovative measure incorporated in several of the educational programmes, including the BSc in Nursing programme, in the Faculty of Health Sciences, at McMaster University, Hamilton, Ontario, Canada is the objective structured clinical examination (OSCE). The purpose of this study was to determine the reliability of this evaluation method, both within and between stations. One problem that has been noted by users of the OSCE method is that performance on individual OSCE stations is poorly correlated across stations, apparently regardless of the particular content of the station. A number of hypotheses have been advanced to attempt to explain this phenomenon: performance of any skill is sufficiently variable that the correlation is poor; different skills have little common basis, so that there is no generalizability from one to another, or reliability of assessment in any one station is low. To test these hypotheses, a study was designed for test-retest and interrater reliability. Students undergoing a 10-station OSCE also repeated their starting OSCE station at the end of the examination circuit. In addition, several stations were rated by more than one observer (interrater). This study of 71 first-year BScN students showed that the interrater reliability was high (ICC = 0.80 to 0.99), and test-retest reliability on the same station was good (ICC = 0.66 to 0.86); however, correlation across stations was low (alpha = 0.198). Thus it is apparent that there is high consistency of repeated performance of a skill but little consistency of performance on different skills.

Clinical Competence↗
PubMed1989

The effects of methadone treatment on the reactivity of the nonstress test.

The effect of methadone treatment on the nonstress test (NST) was studied. Thirty narcotic-addicted gravidas on methadone maintenance underwent NSTs, performed and interpreted in a standard manner, before and 1 hour after taking the usual methadone dose. Urines were screened for commonly abused substances on the day of testing. Mean gestation when tested was 34 weeks and mean methadone dose was 26 mg/day. All urines were positive for methadone, six for cocaine, two for opiates, and one for amphetamines. The reactivity of the NSTs performed 1 hour after methadone ingestion was decreased significantly compared with that of tests performed before medication (P less than .04). Decreases in the frequencies of fetal movements and fetal heart rate accelerations were significant (P less than .001 and P less than .01, respectively). These results suggest that methadone treatment altered the morphology of the NST, which may limit the reliability of this test for determining fetal well-being in these high-risk gravidas if time of medication is not taken into consideration.

Female↗
PubMed1988

[Value of computer-assisted, digital long-term ECG analysis in clinical routine practice].

At present the Holter method (HM) is a frequently used investigational procedure in the clinical routine. It was the aim of a prospective study to evaluate the HM from the user's point of view. Therefore a questionnaire was attached to each analysis report including two main questions, which should be answered by the referring physician: Does the analysis result fulfill the consumer's needs? What consequences are drawn due to the HM results? Among 675 questionnaires returned to the laboratory 75% of the referring physicians felt satisfied by the HM result. Disappointments were predominantly related to too infrequently occurring episodes, which did not appear during one 24-hour recording period. Evaluation of therapy (89%), recording prior to antiarrhythmic therapy (84%) and quantification of well-known arrhythmias were the most successful indications of HM. The tremendous daily variability of infrequent symptoms or arrhythmias were the main causes for unsatisfactory results. A successful HM led predominantly to therapeutic consequences (begin, continuation, change or withdrawal of anti-arrhythmic drugs). In 25% HM was not followed by further therapeutic or diagnostic consequences, so that the indication for the HM should be reevaluated! Diagnostic consequences included repeated HM, ECG-Telephone-Transmission consequences heart catheterisation or electrophysiological procedures. In summary the Holter method satisfies the physician's demands if the expectations do not exceed the limitations of the method.

Adolescent↗
PubMed1988

[Variability of arrhythmias and symptoms--their effect on long-term ECG analysis].

The variability of variables influences conclusions in the measurement of biologic variables particularly if the variability of methodological variables are unidentified or of unknown range. Therefore prior the interpretation of Holter-results the interobserver variability of measured parameters (e. g. arrhythmias) and the system-dependent variables (e. g. reproducibility) have to be recognized. Measuring biologic variables like arrhythmias or symptoms using the Holter method the spontaneous variability of infrequent occurring phenomena has to be taken into account and also their relationship to the recording duration: Infrequent occurring phenomena demonstrate an enormous variability, which could be reduced by lengthening the recording duration beyond 24 hours, especially in the evaluation of an antiarrhythmic therapy to avoid a mimicked therapeutic effect. In symptomatic patients their symptoms can be related to arrhythmias or not if an ECG will be recorded during a typical symptomatic period. This depends on the frequency and on the duration of the symptoms, so that other methods than Holter-monitoring should be considered like event-recording, ECG-telephone-telemetry or electrophysiological investigations. In summary the variability of phenomena captured by the Holter method (e. g. arrhythmias, symptoms) is a major factor, which has to be taken into account to avoid unsatisfactorial use of the Holter method.

Anti-Arrhythmia Agents↗
PubMed1988

Hemostasis in hypertensive disorders of pregnancy.

We studied parameters of hemostasis reported to be altered with "pure" preeclampsia in hypertensive disorders of pregnancy. Plasma fibronectin, antithrombin, and alpha-2 antiplasmin were measured in normal pregnancies (N = 26) and in pregnancies complicated by preeclampsia (N = 19), hypertension (N = 11), and chronic hypertension with superimposed preeclampsia (N = 11). Preeclampsia, both pure and superimposed, was associated with high fibronectin (P less than .001), low antithrombin III (P less than .001), and low alpha-2 antiplasmin (P less than .05) levels, suggesting endothelial injury, clotting, and fibrinolysis, respectively. Alpha-2 antiplasmin was increased with chronic hypertension (P less than .001), regardless of whether there was superimposed preeclampsia. Fibronectin appeared to be more closely linked with preeclampsia than antithrombin III or alpha-2 antiplasmin and may prove valuable in detecting preeclampsia when evaluating hypertension in pregnancy.

Adult↗
PubMed1988

A randomized controlled trial assessing the impact of problem-based versus didactic teaching methods in CME.

A Continuing Medical Education short course was designed to examine the effect of presenting topics in three learning formats - traditional lectures, large-group, case discussions or small-group, problem-solving sessions, on knowledge and performance of family physicians. The physicians in the small group session rated the CME short course higher and performed better on one aspect of patient management than the lecture or large group physicians but there were no other differences between groups on knowledge or physician performance.

Clinical Competence↗
PubMed1987

Effects of aspirin, naloxone and placebo.

This study was designed to examine the effects of aspirin, naloxone and placebo treatment on serum beta-endorphin concentration and joint pain in patients with rheumatoid arthritis (RA). Ten patients with definite or classical RA were studied. All treatments were administered in a randomized sequence. On each study day, the following measurements were carried out at specified time intervals: serum beta-endorphin concentration, serum salicylate concentration and joint pain score on a visual analogue horizontal scale. We conclude that in patients with rheumatoid arthritis suffering from chronic joint pain, serum beta-endorphin does not appear to play a role in pain relief.

Arthritis, Rheumatoid↗
PubMed1987

Measuring change over time: assessing the usefulness of evaluative instruments.

Reliability, the ratio of the variance attributable to true differences among subjects to the total variance, is an important attribute of psychometric measures. However, it is possible for instruments to be reliable, but unresponsive to change; conversely, they may show poor reliability but excellent responsiveness. This is especially true for instruments in which items are tailored to the individual respondent. Therefore, we suggest a new index of responsiveness to assess the usefulness of instruments designed to measure change over time. This statistic, which relates the minimal clinically important difference to the variability in stable subjects, has direct sample size implications. Responsiveness should join reliability and validity as necessary requirements for instruments designed primarily to measure change over time.

Humans↗
PubMed1987

Does intravenous ritodrine therapy cause capillary endothelial damage?

The effects of intravenous (IV) ritodrine therapy on capillary endothelial damage and colloid osmotic pressure were examined in 15 patients in premature labor. Plasma fibronectin, a marker for capillary endothelial damage, did not change significantly after IV ritodrine therapy. Plasma colloid osmotic pressure was lowered following ritodrine therapy (P less than 0.05). Pretreatment plasma fibronectin levels in the study and control groups were similar. Interestingly, pretreatment colloid osmotic pressure in the study group was significantly lower than that of the control group (P less than 0.05). Our data suggest that there is no evidence of capillary endothelial damage following ritodrine therapy. Lower levels of plasma colloid osmotic pressure in patients with preterm labor, which are further reduced with IV ritodrine therapy, may predispose these patients to pulmonary edema.

Adult↗
PubMed1987

Sensitivity to change and the effect of mode of administration on health status measurement.

A measure of global health status, the McMaster Health Index Questionnaire (MHIQ), was assessed to determine two important measurement properties related to its reliability and validity--sensitivity to change and the effect of mode of administration. Ninety-six patients in a physiotherapy clinic were randomly assigned to three mode-of-administration study groups, administered the MHIQ at four points in time including at admission and discharge from the clinic, and assessed for change by their physiotherapist. MHIQ physical function, social function, and emotional function retest scores obtained by self-completion within a 1-week interval were most stable. Physical function scores by any of self-completion, telephone interview, or personal interview were sensitive to change, that is, they improved dramatically by the time of discharge from the clinic. Mode of administration did not affect the size of the change scores. Changes reflected by the physical function scores correlated with changes in physical function reported by a patient's physiotherapist. No systematic changes occurred with social and emotional function scores; this is not surprising in a group of patients with predominantly physical function problems.

Activities of Daily Living↗
PubMed1986

Single-dose pharmacokinetics of 3-O-demethylfortimicin A in humans after intravenous and intramuscular administration.

The pharmacokinetics of 3-O-demethylfortimicin A were evaluated in 16 healthy adult male volunteers after bolus intramuscular (i.m.) and 30-min intravenous (i.v.) infusion administration of doses ranging from 0.25 to 16 mg/kg. Mean calculated peak levels of the drug in plasma after the 0.25-, 0.5-, 1-, 2-, 4-, 8-, and 16-mg/kg i.m. doses were 1.1, 1.9, 3.5, 4.9, 11.0, 21.8, and 41.3 micrograms/ml, respectively, occurring about 60 min after dosing. The biphasic decline in levels of the drug in plasma after i.v. administration was not apparent after i.m. dosing, presumably because absorption of the drug from the injection site obscured the alpha elimination phase. Mean calculated peak levels for the 1-, 2-, 4-, 8-, and 16-mg/kg 30-min i.v. infusions were 5.9, 12.2, 20.1, 36.7, and 66.4 micrograms/ml, respectively. A statistically significant trend of increasing apparent volume of distribution with increasing dose size was noted for the i.m. dose group only. Plasma drug clearance was dose level and route independent, with an excellent linear relationship between the area under the plasma drug level curve and the dose. The mean 0- to 48-h urinary recoveries of 3-O-demethylfortimicin A after the i.m. injections and i.v. infusions were 90 and 102%, respectively. After the i.m. dosings, the half-life of the drug in plasma averaged 2.0 h, and after the i.v. dosings it averaged 2.7 h. The results of the study indicated that most of the drug was cleared by renal mechanisms.

Adult↗