Biomedical subjects
K McManus
Publications and source records attributed to K McManus.
Minimally invasive therapy in thoracic injury.
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The changing face of oesophageal cancer treatment in Northern Ireland.
In the late 1970's the options for treatment of oesophageal cancer were limited. When cure was thought possible, resection was performed by the Ivor Lewis or oesophagogastrectomy techniques. Mortality was high, local recurrence rates disappointing, and long-term survival poor. For those patients whose tumours could not be resected, palliative intubation required open operation with high morbidity, and gave poor quality of life. In 1994, selective screening is diagnosing cancers early, more extensive resections are possible with lower mortality, and fewer local recurrences. Adjuvant therapy is increasing the operability rates. Gradually the facade of poor prognosis is being etched away, so that more patients are being given better quality of life, and cure is a distinct possibility. Palliation can be achieved endoscopically by dilatation, intubation or laser ablation combined with local external beam radiation. Mortality for palliative procedures is now considerably reduced.
Natural history of coronary atherosclerosis using quantitative angiography in men, and implications for clinical trials of coronary regression. The Harvard Atherosclerosis Reversibility Project Study Group.
Previous studies of the natural history of coronary disease generally relied on estimates of percent stenosis derived from visual assessment of the coronary angiogram. In a study of 26 patients, serial quantitative angiography was performed 3 years apart to determine changes in both absolute measurements of the luminal diameter and relative percent stenosis. Initially, the mean minimal diameter of 74 coronary obstructions was 1.94 +/- 0.09 mm, the mean "normal" reference diameter was 3.06 +/- 0.11 mm, and the mean percent stenosis was 37%. At follow-up, there was a mild reduction of 0.12 +/- 0.04 mm (6%) in the minimal diameter (p < 0.005), and an increase in percent stenosis to 39% (p = 0.03). The average diameter of 85 arterial segments without a focal obstruction either initially or at follow-up showed mild but significant progression (-0.11 +/- 0.04 mm; p = 0.02). Using a minimal change of 0.27 mm in arterial diameter as a categoric variable, progression occurred in 26% of 74 arterial segments, no significant change in 65%, and regression in 9%. The only significant determinant of disease progression was the initial severity of disease. Obstructed arteries with a larger initial minimal diameter and presumably milder disease progressed more rapidly than did those with a smaller diameter (r = -0.42; p = 0.0002). There was no effect of age on the rate of progression (r = 0.02; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
Diagnostic rigid and flexible oesophagoscopy in carcinoma of the oesophagus: a comparison.
BACKGROUND: Flexible oesophagoscopy is regarded as superior to rigid oesophagoscopy on the basis of perforation rates as an end point. This advantage may be more apparent than real because no comparison has been made in a diagnostic setting in patients with carcinoma of the oesophagus with both perforation rate and diagnostic efficacy as indices. METHODS: A retrospective analysis was carried out on data on 336 diagnostic oesophagoscopies in patients with carcinoma of the oesophagus, comparing rigid with flexible oesophagoscopy. RESULTS: Both rigid and flexible oesophagoscopies were performed without perforation when they were used for diagnosis only. Rigid biopsy achieved a diagnostic success rate of 99.3%, compared with 80.5% for flexible oesophagoscopy. CONCLUSIONS: Diagnostic oesophagoscopy can be achieved without perforation with either instrument, but the chance of diagnosing carcinoma was significantly greater with the rigid instrument.
The role of rigid oesophagoscopy in oesophageal carcinoma.
The efficacy and safety of rigid oesophagoscopy in diagnostic and therapeutic settings in a consecutive series of 404 patients with oesophageal carcinoma were studied and compared to that for flexible oesophagoscopy in the same group. In addition, we examined the same parameters in a smaller group who had undergone radiotherapy with subsequent malignant stricturing. We performed 328 rigid procedures and 118 flexible procedures in a single regional surgical referral unit over a 7 year period. The combined perforation rate was 1.3%, with an overall mortality of 1% from 446 procedures. We conclude that rigid oesophagoscopy in the presence of carcinoma retains an important diagnostic and therapeutic role which can be achieved with low incidence of perforation in high-risk patients.
What can and what cannot be achieved by nutrition education? A challenge for the 1990s.
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Planning is the key to success.
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Effects of exposure to ethylene glycol ethers on shipyard painters: I. Evaluation of exposure.
An industrial hygiene survey was performed to characterize exposure of shipyard painters to 2-ethoxyethanol (2-EE) and 2-methoxyethanol (2-ME). One hundred and two samples were taken over six workshifts. Overall results showed that the time-weighted average (TWA) of airborne exposure to 2-EE ranged from 0-80.5 mg/m3 with a mean of 9.9 mg/m3 and a median of 4.4 mg/m3. Samples for 2-ME TWA ranged from 0-17.7 mg/m3 with a mean of 2.6 mg/m3 and a median of 1.6 mg/m3. Limitations of the sampling and a few prior measurements suggest that these data may underestimate usual or previous exposure. These data are discussed in the context of available data on airborne exposure to ethylene glycol ethers from other workplaces.
Effect of linoleic and oleic acids on blood pressure, blood viscosity, and erythrocyte cation transport.
It has been proposed that dietary linoleic acid lowers blood pressure (BP) by being converted to arachidonic acid and prostanoids of the two-ene series. We tested the effects of linoleic acid on plasma arachidonic acid, blood pressure, blood viscosity, and RBC cation transport. Oleic acid, the major dietary monounsaturated fat and which is not a prostanoid precursor, was used as a control. Seventeen adults consumed 23 g/d of linoleic acid or oleic acid provided by genetic variants of safflower seed, each for 4 weeks in a double-blind crossover design. Linoleic and oleic acids were enriched significantly in the plasma cholesteryl esters, phospholipids and triglycerides during the respective periods of supplementation but there was no increase in arachidonate. Mean BP was 116.1/76.8 during ingestion of oleic and 113.6/74.6 during ingestion of linoleic acid (p = 0.09 systolic, p = 0.12 diastolic). The power of the study was over 75% for detecting a significant (p less than 0.05) effect of 4 mm Hg in systolic BP or diastolic BP. Whole blood and plasma viscosity, and RBC Li/Na countertransport, Na/K cotransport, and Na pump systems (Vmax) were unchanged during the protocol. Therefore, variations in dietary linoleic or oleic acids are unlikely to have major effects on BP or on several membrane-dependent erythrocyte functions related to hypertension.
Pharmacokinetics, antiarrhythmic effects, and tissue concentrations of amiodarone and desethylamiodarone in dogs with acute coronary artery occlusion.
A single bolus of 5 or 40 mg/Kg of amiodarone was injected 24 hours after inducing coronary artery occlusion in the closed-chest dog preparation. Plasma pharmacokinetic profile was determined and the calculated t1/2 beta of 3.5 +/- 2.8 and 3.2 +/- 0.6 hour after 5 or 40 mg/Kg dose, respectively, were obtained. The major metabolite, desethylamiodarone, was detected within 15 minutes of the single bolus of amiodarone. At 6 hours after amiodarone administration, the animals were killed and tissue concentrations of amiodarone and desethylamiodarone were measured. Two additional peaks in the HPLC chromatograms were observed in plasma and tissue samples of most dogs given 40 mg/Kg I.V. amiodarone and these most likely are due to unidentified metabolites of the drug. The highest drug concentration was found in the lungs. Tissue to plasma drug rations suggested that accumulation of amiodarone and perhaps desethylamiodarone was different for different tissues. Ventricular arrhythmias were not abolished by either of the two doses of amiodarone; however, there was a gradual and statistically significant decrease in the number of ventricular premature beats and ventricular tachycardia beats over the six-hour period after a single 40 mg/Kg I.V. bolus. At the time of reduction in the arrhythmia frequency, tissue levels of both amiodarone and desethylamiodarone in the border and infarct zone of the myocardium were approximately 50% as high as in the normal zone. Plasma drug levels did not correlate well with tissue concentrations. However, there was an excellent correlation between drug levels in WBCs and various tissues except the lung. It is concluded that amiodarone is rapidly metabolized into desethylamiodarone and at least two other unidentified compounds; a large dose of amiodarone is necessary to produce some decrease in ventricular arrhythmias associated with acute coronary artery occlusion; tissue concentrations may be better correlated with drug levels in WBCs than in plasma, and coronary artery occlusion does not affect acute pharmacokinetic profile of the drug.
Bronchogenic cyst presenting as deep neck abscess.
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Selective attenuation of ethanol-induced performance impairment by naloxone in humans.
Healthy human subjects performed a vigilance task involving decision making and motor responses under four drug conditions involving random assignment and double blind procedures. Naloxone (0.4 mg) or saline was injected intravenously before subjects consumed a drink of alcohol (0.56 gm ethanol per kg body weight) or a simulated alcoholic drink. Blood alcohol concentrations averaged 60 mg/dl. The impaired performance of the task by this blood alcohol concentration was ameliorated by prior administration of naloxone at one testing point in the study sequence (40 minutes after ingesting the alcohol). The effect was associated with a history of light drinking (mean intake 0.93 gm/kg of body weight/month). Further studies to characterize this phenomenon more fully are proposed.
Computed tomography in the diagnosis of deep-neck infections.
Computed tomography (CT) of the neck was used to identify deep-neck abscess formation. Twenty-two patients were screened by CT for deep-neck abscesses. Each patient suspected of having a deep-neck infection underwent CT, often with enhancement if the differential diagnosis included the possibility of a tumor or vascular lesion. Six cases were identified, and these patients were taken to surgery for incision and drainage. There were no false-positives or false-negatives in the series. In all six cases of abscesses, the CT scan accurately identified the anatomical location of the abscess, allowing a more accurate planning of the surgical approach. The selective use of CT when deep-neck infections are suspected seems to produce an accurate diagnosis of the presence of an abscess, its location, and the involvement of important surrounding structures.
Prenatal drugs: patient information and its source.
Pregnant women consume numerous medications, some of which are potentially harmful to the fetus. It is especially important that these women are provided with information about these drugs. This study was undertaken, in part, to document the amount of information pregnant women have about the drugs they consume and the sources of their information. Study participants were 304 women selected at random from the postpartum inpatients at a teaching hospital. Mothers were interviewed to obtain drug exposure data and to determine what, if any, information they had about the drugs. The source of information for each drug consumed was also determined. Results show that pregnant women have little information for each drugs they consume. Mothers most often cited primary medical personnel (physicians and nurses) as sources of information about specific drugs. In contrast, only six patients cited the pharmacist as a source of information about specific drugs. However, patients ranked the pharmacist high as a source of general drug information. This report emphasizes the need for more drug information for pregnant women and highlights the role of the pharmacist in providing such information.