Search PubMed⌕ Search

Biomedical subjects

M McLeod

Publications and source records attributed to M McLeod.

54 records · Page 3Linked to original sources
PubMed1984

Urethral stricture following cardiac surgery: a prospective study.

A prospective study was undertaken to assess the incidence of urethral stricture in 105 men undergoing coronary artery by-pass grafting. A pre-operative urological history was taken and peak urine flow rates measured before surgery, and 1 week and between 6 and 8 weeks after operation. All patients were catheterised in theatre with a standard type and size of urethral catheter and details recorded of the by-pass time and the degree of hypothermia. Postoperative urological problems such as urethral discharge and haematuria were noted. In addition, 100 patients completed a postal questionnaire about urinary symptoms between 4 and 12 months after surgery. The overall incidence of urethral stricture was 2%.

Adult↗
PubMed1984

A simple separator to generate half micron aqueous particles for lung imaging.

An aerosol of a radionuclide may be used for ventilation imaging as an alternative to radioactive rare gases. For good-quality images as few particles as possible must be deposited in the trachea and bronchi, which means that no, or very few, particles should have aerodynamic diameter of more than 2 micron. We have developed a separator to modify the output of an Acorn jet nebuliser. It reduced the proportion of particles in the aerosol with aerodynamic diameters of more than 2 micron from 60% for the unmodified output of the nebuliser to only 6%; it consisted of a cylinder of perspex with two compartments containing inert spheres, either stainless steel or glass, of diameter 3 mm (the first compartment contained two layers of spheres, and the main section was packed with spheres). To examine the efficiency of the separator system for routine clinical use we compared the images produced and the deposition of the particles in the modified aerosol (using 99TcmDTPA) with the distribution of ventilation of 81Krm in eight subjects. Despite the theoretical differences between the behaviour of a gas molecule and of a particle in the respiratory tree, the images produced using the modified aerosol delivery system were as good as those produced with 81Krm in normal subjects. In abnormal subjects the images produced were only distinguished following the calculation of a penetration index.

Adult↗
PubMed1982

Effect of compression rate on use of trimix to ameliorate HPNS in man to 686 m (2250 ft).

Previous man dives, in a series designed to evaluate the physiological effects of helium, nitrogen, and oxygen (trimix), investigated the comparative effects of 5% vs. 10% nitrogen with fast compression (12 h 20 min) to 460 m (1509 ft) and subsequent compression over 2.5 d to 650 m (2132 ft). In 1981 three divers were compressed twice as slowly as for these earlier dives to 650 m over a period of 6 d 8 h using 10% N2 in heliox. An extensive series of studies were made over 4 d 15 h at 650 m before further compression to 686 m (2250 ft) for a stay of 24 h with extensive tests of psychological and neurophysiological performance, pulmonary function, reflex, Doppler, and other studies. High pressure nervous syndrome (HPNS) tremors and EEG theta activity increases were effectively controlled with no nausea, vomiting, or somnolence (microsleep). Some euphoria was present. At 686 m there was a 20% to 30% impairment of concentration and attention; otherwise the physical condition of the divers was fine and they completed all tasks without difficulty. Slow compression prevented the initial large performance decrement of 40% to 50% on Day 1 as found in previous fast-compression dives. Otherwise the performance tests showed much the same decrement of 15% to 20% seen in earlier dives; deeper than 570 m (1870 ft), however, the addition test was worse, with a decrement of 35%. The results are discussed with respect to the previous two dives with faster compression, and the possible nonlinearity of nitrogen antagonism of HPNS is considered.

Adult↗
PubMed1981

Cardiovascular effects in man of intravenous prizidilol hydrochloride (SK&F 92657); a new antihypertensive agent.

1 Cardiovascular responses to intravenous prizidilol hydrochloride (SK&F 92657) 0.86 mg/kg were studied in eight supine resting healthy volunteers. Five subjects were slow and the remaining three were fast acetylators of sulphamethazine. Compared with pre-infusion values, mean resting systolic and diastolic blood pressures were significantly reduced, while mean resting pulse rate was significantly increased at 30 min after the start of the twenty minute infusion. 2 During the 6 h study period the lowest mean +/- s.e. mean systolic blood pressure (108.8 +/- 1.7) was recorded 30 min after the start of the infusion. This represented a mean reduction of 5.2 mmHg. Reductions in mean diastolic blood pressure were greater and of longer duration, the lowest mean value (44.8 +/- 2.0 mmHg) being recorded 3.5 h after the start of the infusion and representing a reduction of 18.5 mmHg from the pre-dosing value. At 6 h after the start of the infusion mean diastolic blood pressure was still significantly reduced (by 15.3 mmHg). 3 The maximum mean +/- s.e. mean resting pulse rate (79.3 +/- 4.4 beats/min) occurred 3 h after the start of the infusion, an increase of 23.0 beats/min over the pre-infusion value. At the end of the study the pulse rate was still significantly raised (by 17.7 beats/min). 4 The left ventricular ejection fraction, evaluated in five subjects, 45 min after the start of the infusion, was not altered by prizidilol hydrochloride, but the left ventricular area decreased significantly. 5 Intravenous prizidilol hydrochloride decreases resting blood pressure and left ventricular area, increases pulse rate and has virtually no effect on left ventricular ejection fraction.

Adolescent↗
PubMed1978

A comparison of electroconvulsive therapy and combined phenelzine-amitriptyline in refractory depression.

Combined monoamine oxidase (MAO) inhibitor-tricyclic antidepressant therapy and electroconvulsive therapy (ECT) were compared in a population of refractory depressive patients. Seventeen patients were randomly assigned to either of the treatment groups, and an independent observer was used to rate overall progress. Between four and ten ECTs or a combination of phenelzine and amitriptyline were administered. Assays for MAO activity and plasma levels of amitriptyline and nortriptyline were performed. In both psychotic and neurotic depression, ECT was superior. When depression was accompanied by character disorder, the response was generally poor. Adequate levels of MAO inhibition were obtained, but tricyclic antidepressant levels were low. Electroconvulsive therapy is still considered to be the treatment of choice for severe depression, whereas the combination of low doses of phenelzine and amitriptyline are ineffective. This treatment modality needs further investigation.

Adjustment Disorders↗
PubMed1978

Paramedic use of intracardiac medications in prehospital sudden cardiac death.

The intracardiac administration of medications in cardiac arrest is advocated when an intravenous route cannot be established. Although warnings of complications of this mode of therapy are reiterated throughout the literature, their careful documentation is lacking. Paramedics were trained to administer intracardiac medications, under strict criteria, in patients with prehospital sudden cardiac death. Long-term survivors who received intracardiac medications from paramedics were compared to a control group resuscitated by paramedics with intravenous medications alone. By far, the patients who received intracardiac medications were more nearly refractory to resuscitation because of the criteria for intracardiac medication use. Potential complications of the intracardiac route were identified and sought. However, complications were no more common in this group of patients than in the control group. Paramedics can successfully administer intracardiac medications when indicated.

Allied Health Personnel↗
PubMed1977

Acute fatty metamorphosis of the liver: a report of two patients who survived.

Two patients with acute fatty metamorphosis of the liver of pregnancy who survived are presented. Clinical and pathologic features, possible etiologic factors, and principles of treatment are discussed. Both patients subsequently were allowed to become pregnant again, both had uncomplicated second pregnancies without evidence of liver disease, and both delivered healthy babies.

Acute Disease↗
PubMed1977

Treatment of vulvovaginal candidiasis in pregnancy. A comparative study.

A carefully controlled comparative study showed miconazole nitrate 2% vaginal cream (Monistat) to be a highly effective agent in the treatment of vaginal candidiasis in pregnant subjects. Miconazole nitrate was significantly more effective than nystatin (Mycostatin) in the treatment of vaginal candidiasis in all three trimesters of pregnancy, and also more effective regardless of whether the candidal infection was primary or recurrent. Observations relating to the safety of this therapy during pregnancy were made and discussed.

Acute Disease↗
PubMed1976

Clinical assessment of azapropazone in rheumatoid arthritis.

Azapropazone was investigated in a 2-week double-blind clinical out-patient trial against placebo in 23 patients with definite rheumatoid arthritis. The drug was given at a dose of 1200 mg. per day before food. At this dose level the drug was shown to have an antirheumatic effect in terms of pain relief, articular tenderness and duration of morning stiffness.

Administration, Oral↗
PubMedDate not supplied

The effect of roxithromycin on the virulence of gram-positive cocci.

Antibiotics whose recognized mode of action comprises inhibition of bacterial protein biosynthesis are also recognized to modulate the expression of bacterial virulence factors when incorporated into culture media at sub-MIC levels. In this respect, one of the new macrolides, roxithromycin, has been examined for its effect on toxin/enzyme production by strains of Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae. Biosynthesis of staphylococcal coagulase and DNase could be potentiated, whereas that of staphylococcal alpha-hemolysin, streptolysins O and S, and pneumolysin were unaltered. Expression of one structural virulence factor, pneumococcal polysaccharide, was repressed in the drug's presence, resulting in potentiation of phagocytic ingestion of the drug-exposed bacteria. The drug failed to have any effect on ingestion of Staph. aureus or Strep. pyogenes. These studies provide evidence that roxithromycin may exhibit "added value" as an antibiotic in its ability to potentiate the susceptibility of Strep. pneumoniae to host defenses such as phagocytosis.

Bacterial Proteins↗
PubMedDate not supplied

Viral and chemical tracer movement through contrasting soils.

Land treatment of animal or human waste can result in chemical and microbial contamination of shallow ground water and/or water-ways. We investigated the fate of a host-specific Salmonella bacteriophage and a nonreactive chemical (Br-) tracer when applied to large intact lysimeter soil cores (500 mm diam. by 700 mm high). The soils included a poorly drained Gley Soil and well-drained Pumice, Allophanic, and Recent Soils. A depth of 30 mm of water containing the bacteriophage and Br- was applied to the soil at a rate of 5 mm h(-1) followed by up to about 1.8 pore volumes of simulated rainfall. Resulting leachates, collected continuously over at least one pore volume were analyzed for the bacteriophage and bromide (Br-) tracers. Bromide moved uniformly through the Pumice and Allophanic Soils with peak concentrations at about 1 pore volume, while the bacteriophage was detected only at trace levels or not at all. In contrast, both Br- and bacteriophage tracers moved rapidly through Gley and Recent Soils, appearing early in the leachate and then tailing off. Such flow patterns in the Gley and Recent Soils are indicative of bypass flow. Coarse soil structure in the Gley Soil, and finger-flow due to water repellency in the sandy Recent Soil are considered responsible for the observed bypass flow in these two soils. Allophanic and Pumice Soils have finer, more porous soil structure leading to a predominance of matrix flow over bypass flow. This study suggests vertical movement of viruses varies significantly with soil type.

Animals↗
PubMedDate not supplied

Land application of domestic effluent onto four soil types: plant uptake and nutrient leaching.

Land application has become a widely applied method for treating wastewater. However, it is not always clear which soil-plant systems should be used, or why. The objectives of our study were to determine if four contrasting soils, from which the pasture is regularly cut and removed, varied in their ability to assimilate nutrients from secondary-treated domestic effluent under high hydraulic loadings, in comparison with unirrigated, fertilized pasture. Grassed intact soil cores (500 mm in diameter by 700 mm in depth) were irrigated (50 mm wk(-1)) with secondary-treated domestic effluent for two years. Soils included a well-drained Allophanic Soil (Typic Hapludand), a poorly drained Gley Soil (Typic Endoaquept), a well-drained Pumice Soil formed from rhyolitic tephra (Typic Udivitrand), and a well-drained Recent Soil formed in a sand dune (Typic Udipsamment). Effluent-irrigated soils received between 746 and 815 kg N ha(-1) and 283 and 331 kg P ha(-1) over two years of irrigation, and unirrigated treatments received 200 kg N ha(-1) and 100 kg P ha(-1) of dissolved inorganic fertilizer over the same period. Applying effluent significantly increased plant uptake of N and P from all soil types. For the effluent-irrigated soils plant N uptake ranged from 186 to 437 kg N ha(-1) yr(-1), while plant P uptake ranged from 40 to 88 kg P ha(-1) yr(-1) for the effluent-irrigated soils. Applying effluent significantly increased N leaching losses from Gley and Recent Soils, and after two years ranged from 17 to 184 kg N ha(-1) depending on soil type. Effluent irrigation only increased P leaching from the Gley Soil. All P leaching losses were less than 49 kg P ha(-1) after two years. The N and P leached from effluent treatments were mainly in organic form (69-87% organic N and 35-65% unreactive P). Greater N and P leaching losses from the irrigated Gley Soil were attributed to preferential flow that reduced contact between the effluent and the soil matrix. Increased N leaching from the Recent Soil was the result of increased leaching of native soil organic N due to the higher hydraulic loading from the effluent irrigation.

Agriculture↗