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Biomedical subjects

J N Adams

Publications and source records attributed to J N Adams.

At least 19 recordsLinked to original sources
PubMed2004

Emergency department thrombolysis improves door to needle times.

OBJECTIVE: To identify the effect on door to needle (DTN) time of moving the site of thrombolysis delivery from the coronary care unit (CCU) to the emergency department (ED). To ascertain if moving the site of thrombolysis enables appropriate use of thrombolysis. DESIGN: Prospective cohort study. SETTING: CCU and ED of a 450 bed Scottish district general hospital without on-site primary angioplasty. PARTICIPANTS: Primary site for thrombolysis of patients presenting to the hospital with ST elevation MI (STEMI) moved from CCU to ED on 1 April 2000. Study patients who had a confirmed STEMI and/or received thrombolytic therapy before this date were defined as the pre-change group; those who were diagnosed as STEMI and/or received thrombolytic therapy after this date were defined as the post-change group. STATISTICAL ANALYSIS: Mann-Whitney test was used to compare medians and chi(2) test for categorical data. RESULTS: 1349 patients were discharged from CCU with a diagnosis of STEMI or received thrombolysis in the ED or CCU between April 1998 and April 2002. There were 632 patients in the pre-change group and 654 patients in the post-change group. Sixty three patients were excluded. Median DTN time for the pre-change group (321 thrombolysed patients) was 64 minutes and median DTN time for the post-change group (324 thrombolysed patients) was 35 minutes, a median difference of 25 minutes (95% CI for difference 20 to 29 minutes, p<0.0001, Mann-Whitney U test). A total of 37 patients were thrombolysed but did not have a final diagnosis of STEMI. CONCLUSION: A significant reduction in DTN times accompanied this change in practice in this hospital.

Aged↗
PubMed1998

The persistence of hibernating myocardium after acute myocardial infarction.

OBJECTIVE: To establish the persistence of hibernating myocardium initially detected after myocardial infarction treated with thrombolysis. METHODS AND RESULTS: Fourteen patients underwent gated positron emission tomography with 18-fluoro-deoxyglucose and N13-ammonia at a median of 8 days after first myocardial infarction. Repeat scans were performed at a median of 13 weeks post-infarction. A total of 148 (30.9%) myocardial segments showed reduced N13-ammonia uptake at the time of the first scan compared with 154.5 (32.2%) segments at the time of repeat imaging. The median change in the number of segments with reduced perfusion was -1.0. Initially 13 subjects had hibernating myocardium, seven patients had large areas and six had smaller regions. Six (46.2%) subjects had repeat scans showing unchanged areas of hibernating tissue and seven had second scans demonstrating changes in the size of the region of hibernating myocardium. One patient had no hibernating myocardium on either scan. CONCLUSIONS: Positron emission tomography performed several months after myocardial infarction demonstrates significant changes in myocardial perfusion. However, a reduction in the number of segments with reduced perfusion does not always result in an improvement in myocardial metabolism and contraction. Whilst most regions of hibernating myocardium were still present several months after infarction, in only approximately half was the size of the mismatched region unchanged. Therefore it is not possible to predict the fate of hibernating myocardium which is present after infarction.

Aged↗
PubMed1998

Coronary artery spasm leading to life threatening arrhythmias.

A 39 year old woman sustained life threatening arrhythmias associated with coronary artery spasm. On both occasions she was attending hospital outpatient clinics and was successfully resuscitated. Electrocardiography performed during further episodes of pain suggested that spasm could occur in either the right or left coronary artery.

Adrenergic beta-Antagonists↗
PubMed1997

Heartstart Scotland: the use of paramedic skills in out of hospital resuscitation.

OBJECTIVE: To assess the frequency with which paramedic skills were used in out of hospital cardiac arrest and the effect of tracheal intubation on outcome. DESIGN: Retrospective analysis of ambulance service reports and hospital records. SETTING: Scottish Ambulance Service and hospitals admitting acute patients throughout Scotland. RESULTS: A total of 8651 out of hospital resuscitation attempts were recorded and tracheal intubation was attempted in 3427 (39.6%) arrests. One hundred and thirty six patients (3.7%) were intubated and 476 (9.1%) of the patients who were not intubated survived to hospital discharge (p < 0.001). Among the patients who were defibrillated the proportion intubated was highest in the patients who received the greatest number of shocks (p < 0.01). Among subjects receiving similar numbers of shocks survival rates were lower for intubated patients (p < 0.01). Patients with unwitnessed arrests were most frequently intubated and survival rates were lowest in this group. CONCLUSIONS: Patients who are intubated seem to have lower survival rates. This may however reflect the difficulty of the resuscitation attempt rather than the effects of intubation. The use of basic life support skills rapidly after cardiac arrest is associated with the best survival rates.

Chi-Square Distribution↗
PubMed1996

Incidence of hibernating myocardium after acute myocardial infarction treated with thrombolysis.

OBJECTIVE: To establish the incidence of hibernating myocardium after myocardial infarction treated with thrombolysis and to observe differences in the clinical outcome between patients with and without hibernating tissue. METHODS: 41 patients underwent gated positron emission tomography with 18-fluorodeoxyglucose and 13N-ammonia at a median of eight days after first myocardial infarction. RESULTS: All 41 subjects had a matched perfusion-metabolism deficit in the region of myocardium indicated as the site of infarction by an electrocardiograph; 32 patients (78%) had scans which also showed at least one area of reduced blood flow and contraction with a concomitant increase in glucose uptake, representing hibernating myocardium. Patients were followed up at a median of six months: all 41 were alive and none had sustained a further infarct or cardiac arrhythmia; 17 subjects with hibernating tissue (53.1%) and two without (25%) reported chest pain after myocardial infarction. CONCLUSIONS: Hibernating myocardium is relatively common shortly after myocardial infarction treated with thrombolysis. It does not influence mortality or the incidence of postinfarction chest pain.

Aged↗
PubMed1995

The risks of thrombolysis in patients without acute myocardial infarction.

The risk of administering thrombolysis to patients with suspected myocardial infarction who subsequently do not sustain an infarct, but develop complications associated with thrombolysis is of concern to all physicians. The objective of this study was to ascertain the effect of altering the criteria for the administration of thrombolysis on the number of patients who received thrombolysis in the absence of infarction. During 1990 and 1992 details of all admissions with chest pain were recorded. During 1991 the policy for the administration of thrombolysis was altered so that only patients with ST elevation were eligible. A total of 1473 patients were admitted with chest pain in 1990 and 1967 in 1992. Of the patients admitted in 1990, 663 (45%) had confirmed infarction of whom 378 (57.0%) received thrombolysis. In 1992, 855 (43%) were admitted with infarction and of these 450 (52.6%) had thrombolytic therapy. 118 patients had no evidence of myocardial infarction, but received thrombolysis. 91 (77.1%) were admitted in 1990 and 27 (22.9%) in 1992 (P < 0.01). Of these only 24 (20%) subjects had ST elevation or bundle branch block on the admission electrocardiograph and 41 (35%) had normal tracings. Four (3%) subjects had serious complications of whom one (0.8%) died. The implementation of ECG criteria resulted in a significant reduction in the number of patients without infarction who received thrombolysis, but did not significantly alter the rate of thrombolysis in those with definite myocardial infarction.

Arrhythmias, Cardiac↗
PubMed1995

Women and myocardial infarction: agism rather than sexism?

OBJECTIVE: To determine whether women with myocardial infarction are treated differently from men of the same age and to assess the effect of changes in the coronary care unit admission policy. DESIGN: Clinical audit. SETTING: The coronary care unit and general medical wards of a teaching hospital. In 1990 the age limit for admission to coronary care was 65 years. This age limit was removed in 1991. PATIENTS: 539 female and 977 male patients admitted with myocardial infarction between 1990 and 1992. MAIN OUTCOMES: Admission to the coronary care unit, administration of thrombolysis, and in-hospital mortality. RESULTS: 409 men and 254 women were admitted with myocardial infarction in 1990 and 568 men and 285 women in 1992. Removal of the age limit for admission to the coronary care unit resulted in an increase in the numbers of both sexes admitted with myocardial infarction. In both years, however, proportionately more men with infarction were admitted to coronary care: 226 men (55%) and 96 women (38%) (P < 0.01) (95% CI 7 to 28) in 1990 and 459 men (81%) and 200 women (70%) (P < 0.01) (%CI 2 to 19) in 1992. Some 246 men (60%) and 133 women (52%) with infarction (P < 0.01) received thrombolytic treatment in 1990 compared with 319 men (56%) and 130 women (46%) (P < 0.01) in 1992. The mean age of women sustaining a myocardial infarction was significantly greater in both years studied. In 1992 a total of 78 men (7%) and 34 women (4%) (P < 0.05) admitted with chest pain underwent cardiac catheterisation before discharge from hospital. CONCLUSIONS: Differences in admission rates to the coronary care unit and the rate of thrombolysis between the sexes can be explained by the older age of women sustaining infarction. The application of age limits for admission to coronary care or administration of thrombolysis places elderly patients at a disadvantage. As women sustain myocardial infarctions at an older age they are placed at a greater disadvantage.

Age Distribution↗
PubMed1995

Delay between the onset of symptoms of acute myocardial infarction and seeking medical assistance is influenced by left ventricular function at presentation.

OBJECTIVE: To determine whether the interval between the onset of symptoms of acute myocardial infarction and the patient's call for medical assistance (patient delay) is related to left ventricular function at the time of presentation. DESIGN: Prospective observational study. SETTING: Coronary care unit of Aberdeen Royal Infirmary. PATIENTS: 93 consecutive patients with acute myocardial infarction. MAIN OUTCOME MEASURES: Left ventricular stroke distance, expressed as a percentage of the age predicted normal value, measured first on admission, and then daily for 10 days or until discharge. Patients were questioned at admission to determine the time of onset of symptoms and the time of their call for medical assistance. RESULTS: Median (range) patient delay was 30 (1-360) min. Mean (SD) stroke distance on admission was 70(18)%, rising to 77(19)% on the second recording, and to 84(18)% on the day of discharge. Linear regression of log(e)(patient delay) against first, second, and last measurements of stroke distance gave correlation coefficients of 0.28 (P < 0.01), 0.18 (not significant), and 0.11 (not significant), respectively. CONCLUSIONS: Patient delay within the first 4 h after the onset of symptoms of acute myocardial infarction is positively related to left ventricular function on admission. A possible explanation is that deteriorating left ventricular function influences the patient's decision to call for help. This tendency for patients with more severe infarction to call for help sooner is an added reason for giving thrombolytic treatment at the first opportunity: those who call early have most to gain from prompt management.

Electrocardiography↗
PubMed1995

Aortic distensibility and stiffness index measured by magnetic resonance imaging in patients with Marfan's syndrome.

OBJECTIVES: To use magnetic resonance imaging to measure the elastic properties of the aorta of adults with Marfan's syndrome and to compare these results with those obtained by echocardiography. PATIENTS AND METHODS: 12 patients with Marfan's syndrome and 12 controls matched for age. Transverse luminal areas of the ascending and descending aorta were measured using electrocardiographic gated magnetic resonance imaging. Echocardiography was used to measure the diameter of the ascending aorta and aortic arch in patients with Marfan's syndrome. Blood pressure was measured during both scans. RESULTS: In diastole, transverse luminal areas of the ascending and descending aorta were significantly greater in patients with Marfan's syndrome when measured by magnetic resonance imaging and corrected for body surface area; P < 0.02 and P < 0.05 respectively. Patients with Marfan's syndrome had a higher stiffness index (112.77 v 5.78, P < 0.05) and a lower distensibility (0.0066 v 0.0105, P < 0.05) than controls. Results produced by MRI and echocardiography were not significantly different. CONCLUSIONS: Magnetic resonance imaging gives good quality reproducible images of the ascending and descending aorta. In patients with Marfan's syndrome, aortic distensibility and stiffness index measured by magnetic resonance imaging were abnormal (but did not always relate directly to the size of the aorta.

Adult↗
PubMed1976

Inheritance of nocardiophage phi EC in matings of nocardial lysogens.

Lysogens of Nocardia erythropolis were mated with nonlysogenic strains to study the inheritance of the phi EC prophage. Crosses between lysogenic strains of the Mat-Ce mating type and nonlysogenic Mat-cE strains produced Mat-cE lysogens at a recovery rate of 17%, whereas recombination frequencies between chromosomal traits were about 2.3 x 10(-5). Crosses of lysogenic Mat-cE mating types with nonlysogenic Mat-Ce produced Mat-Ce lysogens at a recovery rate of 19%, whereas recombinants for chromosomal traits were recovered at only 1.8 x 10(-5). Crosses of homologous mating types, lysogenic Mat-Ce with nonlysogenic Mat-Ce or lysogenic Mat-cE with nonlysogenic Mat-cE, failed to transfer the prophage. It was concluded that the phi EC prophage exists as a plasmid and can be transferred at high frequencies with patterns of transfer controlled like typical nocardial fertility. Evidence that the prophage may also exist as an integrated element was observed from recombination analyses.

Bacteriophages↗
PubMed1974

8-classtype tallying device and counter.

An electronic device using transistor-transistor-logic integrated circuits as primary building blocks was designed and constructed to accumulate counts for eight classtypes. Selection of the classtypes is provided for by three encoders, X, Y, and Z. Using these encoders allows selection of memory counters for accumulations of 0 to 99 counts per classtype. Making X, Y, and Z the input equivalents of three genes permitted direct tallying and accumulation of totals of individual phenotypes for recombinant progeny containing three scorable genes. The use of the device as a simple one-of-four colony counter is described. Use of the instrument for obtaining counts of multiply characterized colonies was possible. In all tested instances, tedium and the labor of obtaining differential counts was reduced by more than fourfold with a great increase in accuracy of count accumulations. Complete information is provided for the fabrication of the instrument for use in individual laboratories.

Bacteria↗
PubMed1968

Partial exclusion of the Nocardia erythropolis chromosome in nocardial recombinants.

Segregation of genes specifying nutritional requirements and inhibitor resistance was analyzed in recombinants from crosses of Nocardia erythropolis with N. canicruria. With all employed characters as both selecting and nonselecting markers, a single linear linkage group was depicted with genes in the following order; leu-6 gly-4 purB2 tetA9 his-1 eryA7 strB2 ser-1 arg-1. The relative frequency of crossovers between gene pairs was found to decrease as the map is read from leu-6 to the right. The phenotype for arg-1 was found infrequently in recombinants. This fact, coupled with the observed decrease in crossover frequency dependent upon map position, suggested two alternative explanations to account for the observed results. (i) Zygote formation among these nocardiae is a consequence of partial, oriented chromosome transfer from N. erythropolis to N. canicruria and is similar to the mechanism of polar transfer reported in matings of Hfr by F(-)Escherichia coli. (ii) Being of diverse origin, the chromosomes of N. erythropolis and N. canicruria are not completely homologous, and decrease in crossover frequency dependent upon map position results from such chromosomal heterology. In this hypothesis, the infrequent occurrence of arg-1 among recombinants is considered to be an artifact resulting from the action of a previously unrecognized suppressor gene for arg-1 present in N. canicruria.

Chromosome Mapping↗