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Biomedical subjects

A Morgan

Publications and source records attributed to A Morgan.

At least 253 records · Page 14Linked to original sources
PubMed1978

Lung water changes after thermal burns. An observational study.

Pulmonary extravascular water has been measured as lung thermal volume (LTV) in a group of nine burned patients. Transducer-detectable indicators were used to permit frequent repetition and quick results. Concurrent recordings were made of cardiac output, pulmonary capillary wedge pressure and the usual hemodynamic variables. Moderate elevation of LTV was seen in all, reaching a maximum value before peripheral edema formation was complete. Left heart filling pressures were low as plasma albumin concentration. Clinical pulmonary edema occurred in one patient treated mostly with crystalloid solution. In several, a secondary peak coincided with edema mobilization.

Adult↗
PubMed1978

Significance of fibre length in the clearance of asbestos fibres from the lung.

Rats were exposed by inhalation to radioactive anthophyllite asbestos. Animals were then killed serially over a period of 205 days and the fibre content of the lungs measured radiometrically. The lungs were subjected to selective bronchopulmonary lavage and the mean fibre content determined of free cells recovered from the alveolar spaces. The length distributions of fibres recovered from the lungs by lavage, and of those remaining in the lungs following lavage, were measured. Short (less than 5 micrometer) fibres are cleared from the lung via the conducting airways more efficiently than longer fibres and fibres exceeding 50 micrometer in length are not removed from the lungs by this route. Although fibres of about 200 micrometer in length were present in all the lungs examined, the longest which could be recovered by lavage, once fibre deposited in the airways had been cleared, was only about 100 micrometer decreasing to 60-70 micrometer after 205 days. It is suggested that long fibres are more liable than short to penetrate the alveolar wall as they tend to bridge the alveolar ducts and alveoli.

Animals↗
PubMed1977

Retention, distribution, and excretion of lead by the rat after intravenous injection.

The distribution and excretion of lead was studied during a period of about a week after a single intravenous injection of 203Pb as chloride accompanied by less than 1 microng of lead carrier. The peak concentration in venous blood was reached after about an hour when it contained 35 to 40% of the administered activity. The subsequent decline in concentration was much more rapid than is observed in man. The main storage organs were the kidneys and bone. Initially, 20% of the dose could be accounted for in the kidney and the biological half-life was about 100 hours. The level in bone built up rapidly at first and then more slowly. After a week, between 25 and 30% of the dose was present in bone.

Age Factors↗
PubMed1977

The biological effects of magnesium-leached chrysotile asbestos.

Chrysotile asbestos was leached in N hydrochloric acid for varying times to produce a range of magnesium-depleted samples. The protein adsorptive capacity, the haemolytic activity, and the capacity to cause selective release of acid hydrolases from macrophages were measured for the various samples in vitro. The carcinogenicity of the same materials was determined following intrapleural inoculation in rats. The adsorptive capacity for albumin decreased linearly with magnesium removal. The haemolytic activity also declined until about half the magnesium had been removed, after which there was little further change. The selective release of acid hydrolases from macrophages in culture increased up to the point at which half the magnesium had been removed but by 90% depletion had declined rapidly. The carcinogenicity of 50% -depleted chrysotile was similar to that of intact, but at 90% depletion the incidence of mesothelial tumours had fallen considerably. There was no evidence that the leached samples fragmented more than the unleached in vivo.

Adsorption↗
PubMed1976

Preoperative or postoperative deep-vein thrombosis?

The incidence of deep-vein thrombosis as detected by the 125I-fibrinogen test and confirmed by phlebography was 32% in a high-risk group of patients admitted to hospital more than 4 days before operation. 62% of these thrombi were established before operation. Patients with malignant disease and those receiving preoperative intravenous nutrition were particularly prone to this complication. Recognition that asymptomatic thrombosis may be present before operation helps to clarify many of the enigmatic aspects of this condition, and has important implications for the interpretation of the results of clinical trials of prophylaxis. The condition should be suspected in patients transferred for surgery from medical wards, and prophylactic measures should be commenced at the time of admission in high-risk patients.

Adult↗
PubMed1976

[Treatment of respiratory distress caused by laryngeal obstruction].

Respiratory distress due to laryngeal obstruction produces a more or less dramatic syndrome depending on the cause of the obstruction and its evolution in time. Treatment should be immediate in order to avoid death or cerebral and cardiac sequelae. It consists, above all, of restoring the patency of the respiratory tract, the short-circuit obtained by intubation or tracheotomy should, in no case, leave any laryngeal sequelae. The authors present their personal series based on a study of respiratory distress due to laryngeal obstruction in the child. These observations were obtained from a large series of 480 cases of laryngeal dyspnea observed over the last 5 years on the E.N.T. unit of the Edouard Herriot Hospital in Lyons. They contrast a very small number of sub-glottic laryngitis cases requiring intubation or tracheotomy to a very large number of cases of subglottic laryngitis, even with respiratory distress, which recovered with well designed medical treatment. Foreign bodies, of which they report eleven cases, all required emergency surgery. They emphasize the severity of this cause. As far as papillomas and angiomas are concerned, they require emergency treatment, either straightaway or after a trial of medical treatment.

Adult↗
PubMed1975

Vascular access for dialysis. Technics and results with newer methods.

Over a five year period, 114 patients had one or more secondary operations for access to the circulation for hemodialysis, these being a Thomas femoral shunt, saphenous vein graft, or Sparks mandril graft. The patient group was different from the general dialysis population, containing more females, more patients with diabetes, and more patients with collagen-vascular disease. Comparing duration of utility by the life table method for each technic, the femoral shunt lasted longest but with a high incidence of septic complications, the mandril graft was intermediate, and the saphenous vein graft least durable in use. The mandril is considered a tentative first choice for secondary access when the required maturation time is available.

Arteriovenous Shunt, Surgical↗
PubMed1975

Lung thermal volume in pulmonary edema: effect of positive end expiratory pressure.

Effects of intermittent (IPPB) and positive eng-expiratory pressure (PEEP) ventilation on accumulation of pulmonary edema were compared, in dogs, after infusion of oleic acid. Pulmonary extravascular water was approximated as lung thermal volume (LTV), a double indicator method based on differential transit time for simultaneously injected right-to-left conductivity and thermal pulses. LTV was found to be decreased in animals treated with PEEP. The possibility that observed LTV changes reflect only the effect of PEEP on flow distribution, not lung water, was examined by alternating PEEP and IPPB; short-term changes in LTV did not occur. Mean values of other factors influencing pulmonary water transfer, e.g., pulmonary capillary wedge pressure, serum protein, arterial blood gasses, were not significantly different with or without PEEP. It was concluded that, for the oleic acid lesion, PEEP effects a small reduction in the rate of accumulation of pulmonary edema.

Animals↗
PubMed1975

Deposition and clearance of inhaled fibrous minerals in the rat. Studies using radioactive tracer techniques.

The deposition and clearance of various fibrous materials have been investigated in the rat using radioactive tracer techniques. The materials used include the U.I.C.C. standard reference samples and synthetic mineral fibres. Measurements of total and alveolar deposition were correlated with the AMADs of the radioactive dust samples which ranged from 1 to 2.5 micron. Although total deposition increases steeply over this range, alveolar deposition is relatively constant only increasing from about 10 to 13%. Alveolar deposition is lower than in man, but the maximum in alveolar deposition appears to occur at a similar aerodynamic diameter. Half times of alveolar clearance, measured over a period of several months following single inhalation exposures, were in the range 60-90 days and no significant difference was observed between amphibole and chrysotile asbestos. Autoradiographs of lung sections indicate that alveolar deposition is relatively uniform and occurs right up to the periphery of the lung. Over a period of several months the uniform distribution alters to one in which fibres accumulate in foci which are mainly subpleural. These foci act as centres for the development of nodular fibrosis.

Animals↗
PubMed1975

Nurse-protocol management of low back pain. Outcomes, patient satisfaction and efficiency of primary care.

To test the validity of a nurse-administered protocol for low back pain, a prospective trial of 419 patients was undertaken in a walk-in clinic. In all, 222 patients were randomly allocated to a "nurse-protocol group" in which they were evaluated by one of five nurses using the protocol; the nurses independently managed 53 percent of the patients and referred to a physician patients with potentially complex conditions. In addition, 197 patients in a randomly allocated control group were managed by one of 32 physicians. Care in the experimental and control groups was compared by follow-up telephone contact and by a four-month chart review. There was no significant difference in symptomatic relief or the development of serious disease in the two groups. Nurse-protocol patients expressed greater satisfaction with the care they had received; patient satisfaction correlated positively with symptom relief. In over 95 percent of the patients, there were noncomplex, nonserious, nonchronic conditions as the cause of back pain. We conclude that nurse-protocol management of this generally benign condition in a primary care setting is both effective and efficient.

Adolescent↗