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Biomedical subjects

J Lyons

Publications and source records attributed to J Lyons.

At least 91 records · Page 5Linked to original sources
PubMed1986

The haemodynamic effects of bronchoscopy. Effect of pretreatment with fentanyl and alfentanil.

The cardiovascular responses to bronchoscopy under general anaesthesia were investigated in 36 premedicated patients. Twelve patients acting as controls received a standard intravenous anaesthetic of intermittent thiopentone and suxamethonium. A further 24 patients were given either fentanyl 6 micrograms/kg or alfentanil 18 micrograms/kg intravenously, one minute prior to induction. There were significant rises in systolic arterial blood pressure (p less than 0.05) and in rate pressure product (p less than 0.05) in the patients in the control group, but these changes were not seen in those patients receiving either fentanyl or alfentanil. However, dysrhythmias and ST segment changes indicative of myocardial ischaemia were present in some patients in all three groups.

Alfentanil↗
PubMed1986

Outcome of early surgery after coronary angioplasty.

Nineteen of 69 patients undergoing coronary angioplasty required immediate coronary surgery after the procedure. Six of these operations were planned as a result of angioplasty that failed without producing any complication. The remaining 13 cases were operated upon because complications occurred during angioplasty. These were coronary artery dissection in four, occlusion in five, continuing severe spasm in two, tamponade in one, and in one other detachment of a guidewire tip. In these 13 cases the vessel in which angioplasty had been attempted was the left anterior descending coronary artery in eight, the right in four, and the circumflex artery in one. This distribution was no different from that in the 56 patients without complications. There was one early postoperative death due to extensive anterior myocardial infarction, and there was electrocardiographic evidence of new infarction in three other patients. A mean of 16 months postoperatively, 16 of the 18 surviving patients had no cardiac symptoms, while angina had improved in the remaining two. Sixteen of the 18 patients had nuclear left ventricular angiography after a mean of 27 months. When the results of this investigation were compared with the left ventricular cineangiograms performed before angioplasty was attempted only two patients showed evidence of a new left ventricular wall motion abnormality. Prompt operation after complications of angioplasty is usually successful with good symptomatic relief and without left ventricular damage. The incidence of complications requiring operation, however, was high in this group of patients, most of whom had single vessel coronary artery disease.

Aged↗
PubMed1986

Inhalation of china stone and china clay dusts: relationship between the mineralogy of dust retained in the lungs and pathological changes.

A combined clinical, radiological, pathological, and mineralogical study was undertaken on 62 cases referred to the Medical Research Council Pneumoconiosis Unit by the Cardiff Pneumoconiosis Panel as Cornish china clay workers. Considerable pathological lesions were found in the lungs, both nodular and interstitial fibroses being present. Some men had worked with china stone but others had worked entirely with china clay. Nodular fibrosis appeared to be related to a high quartz content of the dust recovered from the lung, whereas among those with a high content of kaolinite dust in the lungs interstitial fibrosis was observed.

Adult↗
PubMed1984

Electrophysiologic effects and mechanisms of termination of supraventricular tachycardia by intravenous amiodarone.

Electrophysiologic studies were performed in nine patients with reentrant paroxysmal supraventricular tachycardia (PSVT) during a control period and following 5 mg/kg body weight of intravenous amiodarone (Cordarone, Labaz) administered as a slow continuous infusion over 15 to 20 minutes. All nine patients had induction of sustained PSVT during control studies. In seven of nine patients (group 1) the tachycardia was due to atrioventricular (AV) nodal reentry, and in two of nine patients (group 2) a concealed retrograde bypass tract was incorporated in the reentrant process. In group 1, following amiodarone, all seven patients lost the ability to sustain PSVT with either absence of atrial echoes (one patient) or induction of less than or equal to 3 echo beats (six patients) with termination of PSVT in the antegrade pathway (three patients) or retrograde pathway (two patients) or both (one patient). In group 2, following amiodarone, both patients lost the ability to sustain PSVT with absence of atrial echoes (one patient) on induction of a single echo beat (one patient) with block in the retrograde pathway (i.e., the concealed retrograde bypass tract). Amiodarone significantly increased (1) atrial cycle length for AV nodal Wenckebach block, (2) antegrade functional refractory period of the AV node, (3) antegrade effective refractory period of the AV node, (4) ventricular paced cycle length for ventricular atrial block, and (5) the retrograde functional refractory period of the ventricular-atrial conducting system.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Programmed electrical stimulation in patients with high-grade ventricular ectopy: electrophysiologic findings and prognosis for survival.

The significance and treatment of ventricular premature beats (VPBs) in patients without sustained ventricular tachycardia (VT), sudden death, or syncope remains unclear. We undertook a prospective study of programmed electrical stimulation (up to two extrastimuli and burst pacing) in 73 patients (age 60 +/- 10 years) with high-grade VPBs who had no evidence of sustained VT, sudden death, or syncope as determined by 48 hr of monitoring in the cardiac care unit and 48 hr Holter monitoring. Fifty-six patients (76.7%) had atherosclerotic heart disease, 10 (13.7%) had cardiomyopathy or valvular heart disease, and seven (9.6%) had no evident heart disease. Thirty-seven patients (50.7%) had Lown grade IVB VPBs, 30 (41.1%) had Lown grade IVA VPBs, and six (8.2%) had Lown grade III VPBs. Programmed electrical stimulation identified two groups of subjects: group 1 comprised 20 patients (27%) in whom VT or ventricular fibrillation was induced, group 2 comprised 53 patients (73%) in whom no ventricular arrhythmia or only two to four repetitive ventricular responses were induced. There was a significant difference between the presence of atherosclerotic heart disease, old myocardial infarction, and ejection fraction of less than 40% in group 1 compared with group 2. However, there was no significant difference in the grade of VPBs between the two groups. Seventeen of 20 patients from group 1 were placed on antiarrhythmic therapy (defined by programmed electrical stimulation), whereas group 2 patients were randomly assigned to prophylactic antiarrhythmic therapy. A total of 70 patients were followed up for 30 +/- 15 months. The incidence of sustained VT and/or sudden death (31.5% vs 2%; p less than .001) was significantly higher in group 1 compared with group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Comparison of Hexabrix 320 and Conray 420 for left ventriculography in patients with coronary artery disease.

We compared Hexabrix 320 (580 mOsm kg-1) with Conray 420 (2500 mOsm kg-1) for left ventriculography using a prospective randomised double-blind protocol. One hundred consecutive patients with suspected coronary disease were assigned to Hexabrix (52) or Conray (48) for left ventriculography (dose 10 ml m-2 BSA; flow rate 12 ml s-1). Thirteen patients found Hexabrix unpleasant compared with 24 receiving Conray; overall the feelings of warmth and discomfort were less with Hexabrix than Conray (p less than 0.01 and p less than 0.02 respectively). The incidence of nausea, vomiting, and hypersensitivity was similar. Angiographic quality was better with Conray than with Hexabrix (p less than 0.05). Average changes in heart rate and systolic pressure were similar, though there was greater variation in systolic pressure change after Conray (p less than 0.025). End diastolic pressure increased more after Conray than after Hexabrix (p less than 0.05). These slight advantages of Hexabrix over Conray may be valuable in patients requiring multiple angiograms or in those with impaired cardiac function, but do not justify its use for routine angiography.

Adult↗
PubMed1983

Acquired hypogammaglobulinemia following infectious mononucleosis.

The case of a 17-year-old male who developed hypogammaglobulinemia following infectious mononucleosis is presented. The family history revealed that a male sibling had died some years earlier with encephalitis also following infectious mononucleosis. Laboratory investigations revealed adequate numbers of T and B cells and normal proportions of helper and suppressor T lymphocytes but poor in vitro responses to mitogens and an absence of hypersensitivity to skin test antigens. Serial serological examinations for Epstein-Barr virus antibodies indicated a primary immune response to this virus in a hypogammaglobulinemic individual. The patient probably represents a case of the X-linked lymphoproliferative syndrome. The unique feature of the present case is the demonstration of Epstein-Barr virus-specific T-cell memory. The significance of this finding and the variable expression of this syndrome in two members of the same family are discussed.

Adolescent↗
PubMed1983

Cirrhosis, encephalopathy, and improved results with metabolic support.

Twenty-two patients with cirrhosis and acute encephalopathy who were refractory to medical therapy were entered into a randomized, double-blind prospective trial. This trial consisted of either neomycin or a modified amino acid solution rich in branched chains and low in aromatic amino acids and methionine (F080) in the presence of isocaloric amounts of dextrose. The groups were indistinguishable from each other by clinical or laboratory criteria; they were primarily patients who had undergone operation and they would tolerate only 30 gm of oral protein or intravenous standard amino acids. The group receiving F080 had a faster and more complete improvement in encephalopathy. This improvement correlated with the plasma molar ratio and occurred with a lower mortality rate. In addition, the patients also tolerated twice the amino acid load without encephalopathy and were in positive nitrogen balance. Modified metabolic support is effective in the setting of acute liver failure in chronic cirrhosis, particularly in patients who have undergone operation.

Adolescent↗
PubMed1982

Branched chains support postoperative protein synthesis.

A blinded, prospective trial of the effects of branched-chain amino acid (BcAA)-enriched total parenteral nutrition (TPN) versus standard TPN was undertaken in nonseptic noncirrhotic abdominal surgery patients and patients with multiple traumatic injuries. The study reflected data from the immediate 7-day postoperative period. With isocaloric and isonitrogenous input, the BcAA-TPN patients achieved positive nitrogen balance on day 3. Although the urinary nitrogen output was decreased by day 3 in BcAA-TPN, the plasma BcAA levels did not increase until day 6. With no change in 3-methylhistidine urinary excretion, the early nitrogen retention with BcAA-TPN probably reflects a stimulation of protein synthesis. The ability to favorably modulate the metabolic stress response with alternate fuels has become a clinical reality.

Adult↗
PubMed1980

Role of magnesium in the enzyme-linked immunosorbent assay for lipopolysaccharides of rough Escherichia coli strain J5 and Neisseria gonorrhoeae.

An enzyme-linked immunosorbent assay for antibody to the lipopolysaccharides (LPSs) of a rough strain of Escherichia coli (J5) and Neisseria gonorrhoeae was developed. When standard methods of this assay were applied to these LPSs, no antibody was measured. By radiolabeling smooth and rough endotoxins with 51Cr, it was discovered that the rough LPS was not adhering to the polystyrene tubes. When Mg++ was added, however, all endotoxins absorbed to the solid phase. With this assay antiserum to core glycolipid had higher titers against its smooth parent strain than did homologous glycolipid had higher titers against its smooth parent strain that did homologous antiserum, and antisera to gonococci had high homologous but low heterologous titers. Thus, these data demonstrate that bulky O side chains do not hinder the penetration of antibody to core glycolipid and that LPSs from gonococci are heterogeneous but do cross-react.

Animals↗
PubMed1979

Three-month inhalation exposure study with methane sulfonylfluoride.

The effects of exposure to methane sulfonylfluoride at concentrations of 20 or 100 ppb for a total of 61 exposures of 7 hours each were studied in male and female rats. The control and exposed groups did not differ in appearance, behavior, weight gain or food consumption. There was no effect on plasma cholinesterase. RBC cholinesterase was significantly depressed in the high-level male and female exposure groups. There was no significant accumulation of fluoride in either the liver or blood at either exposure level.

Aerosols↗