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Biomedical subjects

M J Cooper

Publications and source records attributed to M J Cooper.

At least 109 records · Page 6Linked to original sources
PubMed1988

Quantitation of day to day variability in mode of induction of ventricular tachyarrhythmias by programmed stimulation.

Spontaneous day to day variability in the mode of induction of ventricular tachycardia at programmed stimulation in the drug-free state has been described but not quantitated. To quantitate this variability, this study employed a new protocol of programmed stimulation in which the number of extrastimuli required for tachycardia induction was the only major stimulation variable. This protocol was applied to 18 consecutive patients with previously documented sustained ventricular tachyarrhythmia due to coronary artery disease. One to seven extrastimuli were available for arrhythmia induction if required. Each patient underwent programmed stimulation in the absence of antiarrhythmic drugs on 3 separate days with a mean interval of 5 +/- 2.7 days between studies. A sustained ventricular tachyarrhythmia was inducible in all studies with less than or equal to 4 extrastimuli; the mean number of extrastimuli required was 2.4 +/- 0.8. Day to day variability in the number of extrastimuli required for tachycardia induction was observed in the majority of patients (72%). Eleven patients (61%) varied by one extrastimulus over the three control studies, and two patients (11%) varied by two extrastimuli. At analysis of variance, the 95% confidence interval for the degree of day to day variability was +/- 1 extrastimulus from the mean number required in the three studies. Multiple configurations of induced ventricular tachycardia were frequently observed at repeat studies and occurred in 15 patients (83%). In conclusion, spontaneous day to day variability in mode of induction of ventricular tachycardia in the absence of drugs is common.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗
PubMed1988

Effect of repetition of extrastimuli on sensitivity and reproducibility of mode of induction of ventricular tachycardia by programmed stimulation.

This study examined the effect of repeating the delivery of a programmed extrastimulus that previously failed to induce ventricular tachycardia, without the usual practice of concurrently altering other stimulation variables such as pacing site or basic cycle length. The impact of such repetition on both sensitivity and day to day variability in mode of arrhythmia induction was assessed in 24 patients with documented sustained ventricular tachycardia or fibrillation. Programmed stimulation in the absence of drugs was performed in each patient on 3 separate days. In the first 12 patients, each extrastimulus was scanned through diastole to refractoriness four times if no ventricular tachyarrhythmia was induced (longitudinal repetition); in the second 12 patients, each extrastimulus was delivered four times at a particular coupling interval before the interval was decreased in 10 ms steps to a closer coupling interval (lateral repetition). Day to day reproducibility of the mode of arrhythmia induction was compared with reproducibility in a control group of 18 similar patients studied previously on 3 separate days without repetition. A sustained ventricular tachyarrhythmia was inducible in all studies with four or fewer extrastimuli. In the group studied with longitudinal repetition, there was a 25% increased yield of induced ventricular tachycardia due solely to repetition of each extrastimulus scan, and the 95% confidence limit for tachycardia induction with any extrastimulus was achieved by delivering that extrastimulus three times. In the group studied with lateral repetition, there was also an increased yield of induced ventricular tachycardia at any extrastimulus coupling interval achieved by repetitive delivery of that coupling interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Evaluation of the responsiveness of elevated pulmonary vascular resistance in children by Doppler echocardiography.

Changes in the Doppler indexes, acceleration time (AcT), right ventricular ejection time (RVET), AcT/RVET ratio and pulmonary artery peak velocity were measured as were changes in pulmonary artery pressure and pulmonary vascular resistance in 21 children with pulmonary hypertension due to a large interventricular communication. In 11 children pulmonary vascular resistance was greater than 4.6 U/m2 (mean 8.6 +/- 1.6), whereas in 10 it was less than 4.5 U/m2 (mean 3.4 +/- 0.2). Although both groups demonstrated acceleration time and AcT/RVET values above normal, there were no significant differences in these values between the groups with high and low pulmonary vascular resistance. With administration of a pulmonary vasodilator pulmonary vascular resistance decreased in 11 responders by greater than 50% of baseline values (from 5.3 +/- 0.7 to 1.6 +/- 0.3 U/m2), whereas in the 10 nonresponders mean pulmonary vascular resistance decreased from 7.0 +/- 1.9 to 4.9 +/- 1.1 U/m2. There was no significant change in the Doppler indexes except for an increase in pulmonary artery peak velocity in the responders from 1.34 +/- 0.07 to 1.66 +/- 0.06 m/s (p less than 0.001). The results indicate that Doppler echocardiography cannot predict either the level of increased pulmonary vascular resistance or the degree of responsiveness sufficiently to obviate the need for cardiac catheterization in patients with interventricular communication and pulmonary hypertension.

Adolescent↗
PubMed1987

Resection in chronic pancreatitis.

In the absence of ductal ectasia there is no adequate alternative to pancreatectomy for severe chronic pancreatitis. A personal series of 30 such patients operated upon between 1977 and 1984 included 16 with distal pancreatectomy, 6 with proximal pancreatectomy and 12 with total pancreatectomy; 4 patients progressed from distal to total resection after an interval of 15-28 months. The mean age was 39 years with a male preponderance of 77 per cent. The main aetiological agents were chronic alcoholism (63 per cent) and previous acute pancreatitis (23 per cent). One patient died after total pancreatectomy, giving a 30-day mortality rate for all resections of 3 per cent. Postoperative complications necessitated reoperation in 10 per cent, and there have been 5 late deaths (17 per cent). Among 27 patients followed for a median of 4.5 years, pain relief has been good in 16, fair in 8 and poor in 3 (11 per cent). Proximal pancreatectomy has proved superior to distal pancreatectomy with regard to analgesia and the avoidance of diabetes. Although technically demanding, total pancreatectomy has improved symptoms substantially in 9 of 10 patients surviving for a minimum of 18 months.

Adult↗
PubMed1987

Total pancreatectomy for chronic pancreatitis.

A survey of six British centres collected data on 83 patients undergoing total pancreatectomy (TP) for chronic pancreatitis between 1977 and 1986. There were 57 men and 26 women with a median age of 38 years (range 19-61 years). Half were alcoholics and half had had previous acute pancreatitis. Besides jaundice (14 per cent) severe pain was the indication for the operation; regular opiates had been needed in 82 per cent of patients and 37 per cent were addicted to these drugs. All but 12 had had previous pancreatic or biliary surgery, with a median of two operations and a maximum of six. TP was a one-stage procedure in 32 patients, 42 had had distal resections and 9 proximal resections in the past; the pylorus was preserved in 30. Median operation time was 4 h (range 2-18 h) and median blood loss was 3 units (1-21 units). Intraoperative complications in 11 patients included haemorrhage in 9. Four deaths occurred within 30 days from bleeding (2), respiratory failure (1) and Roux-loop infarction (1). All but one of the 79 survivors required full pancreatic supplementation and 38 per cent had difficulties in endocrine control. At a median follow-up of 1.5 years (range 0.25-10 years), 57 patients (72 per cent) were pain-free and 9 (11 per cent) needed only occasional analgesia. Though 13 (17 per cent) still took regular analgesics, all were symptomatically improved. There have been 10 late deaths (13 per cent), all but one of which are attributable to the operation.

Adult↗
PubMed1987

Psoas abscess in Bristol: a 10-year review.

A consecutive series of 16 cases of psoas abscess managed over a 10-year period at the Bristol Royal Infirmary is presented. Tuberculosis accounted for 4 patients all normally resident in the United Kingdom. Intraabdominal inflammatory disorders accounted for 9 of the cases with Crohn's disease being the commonest of these with 5 cases. The remaining patients comprised 3 with primary staphylococcal abscesses, one appendicitis, one diverticulitis and 2 with colonic carcinoma. Diagnostic delay was common. Ultrasonography together with guided aspiration of pus was the most useful investigation giving the diagnosis in cases due to tuberculosis and staphylococci. The presence of gut associated organisms was indicative of gastrointestinal pathology. Four patients died and significant morbidity occurred in a further 5. We recommend effective dependent drainage together with resection of diseased gut in the cases of gastrointestinal origin.

Abscess↗
PubMed1987

Diagnosis of inferior myocardial infarction in the presence of left anterior hemiblock.

Inferior myocardial infarction results in Q waves in the inferior leads of the electrocardiogram (ECG). Left anterior hemiblock results in initial r waves in these leads. Thus the diagnosis of one in the presence of the other is difficult. It has been reported that inferior infarction can be diagnosed in the presence of left anterior hemiblock when there is a q wave or q equivalent in lead II, and that part of the inferior wall must be spared, to result in the initial r waves of left anterior hemiblock in leads III and aVF. We examined these concepts in 18 patients with such an ECG, by means of resting myocardial perfusion (thallium-201) scintigraphy. In 15 there were defects in the inferior left ventricular wall consistent with inferior infarction. In all of these patients there was sparing of part of the inferior wall: in nine, sparing of the posterior part, and in six, sparing of the anterior part. We conclude that in apparently isolated left anterior hemiblock, a q wave or q equivalent in lead II is an important sign, indicating the likelihood of associated inferior infarction.

Diagnosis, Differential↗
PubMed1987

Ileal carcinoma and tuberculous ileitis.

A 76 year old woman presented with abdominal pain and weight loss. At laparotomy she was found to have an adenocarcinoma of the ileum arising in a segment of tuberculous ileitis. The possible significance of this association is discussed.

Adenocarcinoma↗
PubMed1986

Intragastric bile acids and scintigraphy in the assessment of duodenogastric reflux.

Following endoscopic gastric juice aspiration, intragastric bile acids were measured in 105 patients undergoing routine or review gastroscopy. Subsequently, duodenogastric reflux was assessed using 99mTc butyliminodiacetic acid (BIDA) scintigraphy and intragastric bile acid levels compared with the grades of reflux assessed scintigraphically. There was a significant correlation between both free and total intragastric bile acid levels and the degree of radiological bile reflux, especially when reflux was severe. Both endoscopic measurements of bile acids and BIDA scintigraphy appear to be useful methods for determining duodenogastric reflux, but neither may be accurate enough to quantify minor degrees of reflux.

Bile Acids and Salts↗
PubMed1986

Intragastric bile acids and histological changes in gastric mucosa.

Multiple gastric biopsies and gastric juice aspirates were taken in 108 patients undergoing routine or review gastroscopy for a variety of upper gastrointestinal disorders. The gastric juice was measured for free and total bile acids and the biopsies examined for premalignant mucosal changes. Total bile acid levels were significantly higher in patients with atrophic gastritis, intestinal metaplasia and dysplasia but not chronic gastritis. There was no correlation between the severity of the dysplasia and total bile acid levels. Free bile acid levels were significantly higher in patients with atrophic gastritis but not in patients with chronic gastritis, intestinal metaplasia or dysplasia. These results suggest that intragastric bile acids may be implicated in premalignant histological changes of gastric mucosa and thus play a part in gastric carcinogenesis.

Atrophy↗
PubMed1986

Impaired spermatogenesis in testes at risk of torsion.

The oligospermia observed after unilateral torsion of the spermatic cord could reflect immunological damage to the opposite testis. An alternative explanation, that there may be a pre-existing defect in spermatogenesis, was tested in 20 post-pubertal males with acute torsion. In a prospective study the contralateral testis was biopsied at operation and the histological appearances were related to subsequent testicular function as assessed by seminal analysis 3 months later. Thirteen patients had biopsy evidence of partial maturation arrest in spermatogenesis which was either mild (6), moderate (4) or severe (3), and ten of these were oligospermic (less than 20 X 10(6)/ml). By contrast all seven patients with normal histology had a sperm concentration greater than 25 X 10(6)/ml. Histological grading of spermatogenesis by the Johnsen technique gave a higher score in patients with a normal biopsy (median 9.01, semi-quartile range 8.96-9.21) than in those with abnormal histology (median 8.28, semi-quartile range 7.98-8.45, P less than 0.001) and correlated with the log of the sperm concentration 3 months later (r = 0.79, P less than 0.001). There was minimal anti-sperm and no anti-testis antibody formation following torsion. Serum FSH levels were raised in 6 of 10 oligospermic patients, while all those with a normal sperm count had FSH concentrations within the normal range. Thus many patients who develop testicular torsion have an underlying defect in spermatogenesis, which correlates closely with poor postoperative exocrine function.

Adult↗
PubMed1986

Contrast echocardiography in the diagnosis of anomalous left coronary artery arising from the pulmonary artery.

We have demonstrated an anomalous left coronary artery originating from the main pulmonary artery by saline contrast echocardiography. The anomalous vessel was easily identified using contrast injections into the ascending aorta at catheterization and into a radial artery cannula following catheterization. Contrast echocardiography may be useful in the diagnosis of this lesion when two-dimensional and Doppler echocardiography fail to show the anomalous vessel.

Cardiac Catheterization↗
PubMed1986

A comparative trial between cefotetan and cephazolin for wound sepsis prophylaxis during elective upper gastrointestinal surgery with an investigation of cefotetan penetration into the obstructed biliary tree.

Cefotetan is a cephamycin antibiotic theoretically suited to prophylaxis of wound infection during upper elective gastrointestinal surgery. In a prophylaxis trial 100 patients undergoing this type of surgery were randomly allocated to receive 1g cefotetan or cephazolin iv at induction of anaesthesia. Cefotetan-treated patients had significantly fewer postoperative infections overall (P less than 0.05) and there were no wound infections recorded in this group. In a separate pharmacokinetic study the penetration of cefotetan into common bile duct bile and gallbladder wall was measured in a further six patients, all of whom had been jaundiced preoperatively. At the time of maximum risk concentrations of cefotetan in bile and biliary tissue as well as blood and wound fat were in excess of the minimum inhibitory concentration for the majority of relevant pathogens. Cefotetan appears to be equally or more effective than cephazolin and is a suitable alternative prophylactic agent in elective upper gastrointestinal surgery.

Bile↗
PubMed1986

Pseudo-pseudocysts of the pancreas.

Pancreatic pseudocyst was erroneously diagnosed in three patients aged 52-57 years. Two patients had acute epigastric pain, hyperamylasemia (approximately 4,000 IU/L), and a retrogastric collection of fluid demonstrated by early ultrasonography. Laparotomy undertaken within 48 h of admission revealed the correct diagnosis in each case. One patient had perforation of a gastric ulcer into the lesser sac, and the other patient (who died) had perforation of an obstructed afferent loop 25 years after Polya partial gastrectomy. The third patient with renal failure, back pain, and marginal hyperamylasemia had a cystic mass in the lesser sac. Two internal drainage operations were performed before the correct diagnosis of epithelioid leiomyoma was established 6 years later.

Diagnosis, Differential↗
PubMed1986

Prognostic significance of ventricular tachycardia and fibrillation induced at programmed stimulation and delayed potentials detected on the signal-averaged electrocardiograms of survivors of acute myocardial infarction.

The relative prognostic significance of ventricular tachycardia and ventricular fibrillation inducible at programmed stimulation within 1 month of acute myocardial infarction was compared in a prospective study of 403 clinically well survivors of transmural infarction who were 65 years old or younger. The prognostic significance of delayed potentials on the signal-averaged electrocardiogram was also examined in a subset of 306 patients without bundle branch block. Among the study patients, 20% had inducible ventricular tachycardia, 14% had inducible ventricular fibrillation, and 66% had no inducible arrhythmias. The 2 year probability of remaining free from cardiac death or nonfatal ventricular tachycardia or fibrillation was 0.73 for those with inducible ventricular tachycardia, 0.93 for those with inducible ventricular fibrillation, and 0.92 for those with no inducible arrhythmias. The cycle length of inducible ventricular tachycardia was 230 msec or more in 70% of the patients with inducible tachycardia who died. Of the patients studied by signal-averaged electrocardiography, 26% had delayed potentials. At 2 years, the probability of remaining free from cardiac death or nonfatal ventricular tachycardia or fibrillation was 0.73 for patients with delayed potentials and 0.95 for patients with no delayed potentials. There was a significant correlation (p less than .001) between the presence of delayed potentials and the ability to induce ventricular tachycardia. In conclusion, in survivors of recent infarction who have not had spontaneous ventricular tachycardia or fibrillation, inducible tachycardia (but not inducible fibrillation) at programmed stimulation predicts a significant risk of death or spontaneous tachycardia or fibrillation. A similar risk is found for patients with delayed potentials on the signal-averaged electrocardiogram.

Adult↗