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Biomedical subjects

S F Smith

Publications and source records attributed to S F Smith.

At least 55 records · Page 3Linked to original sources
PubMed1987

Effects of cigarette smoking and drugs on respiratory tract proteases and antiproteases.

Increased pulmonary proteolytic (elastolytic) activity is thought to be the primary cause of emphysema and may also play a rôle in the pathology of bronchitis. These diseases are common amongst tobacco smokers. Serum-derived alpha 1-proteinase inhibitor (alpha 1PI) and locally produced protease inhibitors normally protect the pulmonary epithelium from proteolytic attack, but tobacco smoke can inactivate these antiproteases by oxidative and non-oxidative mechanisms. Bronchoalveolar lavage fluid (BALF) samples lung surface components and most studies show that there is elevated elastolytic activity in smokers' BALF. Whether antiproteolytic capacity is reduced in these samples remains debatable. A selective lavage technique is described which independently samples central and peripheral epithelium from the same subject. Analysis demonstrates a protease-antiprotease imbalance which can differ in central and peripheral lavage and which could be significant in the development of obstructive airways disease. Therapeutic approaches include augmenting antiprotease potential using genetically engineered, oxidant-resistant alpha 1PI or synthetic peptide inhibitors.

Epithelium↗
PubMed1986

Intrapartum fetal heart rate monitoring in a combined low- and high-risk population: a controlled clinical trial.

In a prospective clinical randomized investigation 487 women had the condition of the fetus during labour supervised by means of stethoscope (AUS), while 482 women went through labour under surveillance of electronic fetal monitoring, cardiotocography (EFM). 349 women refused to participate in the investigation (NAI) and had delivery conducted according to the normal procedures of the department (70% AUS, 30% EFM). Significantly more pathological fetal heart rate patterns (FHR) were found in the EFM group compared to the AUS group in both the first and the second stage of labour. As a result significantly more vacuum extractions were performed in the EFM group than in the AUS group, while no statistical difference was found between the groups in the incidence of acute cesarean sections carried out for asphyxia. One case of intrapartum death occurred in the AUS group. No differences were found in Apgar scores after 1 and 5 min or in neonatal morbidity at examination on the 2nd and 5th days after delivery. A tendency towards more biochemically compromised children was found in the AUS group. The specificity for both methods was found to be acceptably high (80%), while the predictive value for both methods was low (50%). More research is therefore urgently needed to evaluate supplementary investigations and parameters for the evaluation of the intrapartum fetal condition.

Acid-Base Equilibrium↗
PubMed1986

Acid-stable low molecular mass proteinase inhibitors in human lung lavage.

An acid-stable, low molecular mass proteinase inhibitor, bronchial mucus proteinase inhibitor (BMPI), has been isolated from sputum and partially characterised. A single band with a modal molecular mass of 18 700 was observed following SDS-polyacrylamide gel electrophoresis. BMPI inhibited human leukocyte elastase, cathepsin G, trypsin and chymotrypsin, but not porcine pancreatic elastase. Although BMPI had a molecular mass close to the similarly isolated inhibitor of Girard et al. (Girard, F., Tournier, J.M., Polu, J.M. & Sadoul, P. (1980), Bull. Eur. Physiopathol. Respir. 16 (Suppl.) 237-245), and although it showed immunological cross reactivity to the low molecular mass inhibitor of Kramps et al. (Kramps, J.A., Franken, C., Meyer, C.J.L.M. & Dijkman, J.H. (1981) J. Histochem. Cytochem. 29, 712-719), it was found to have an amino-acid profile different to any previously described inhibitor. BMPI was detectable in bronchoalveolar lavage fluid collected from healthy and diseased human lungs. The median molar ratio of BMPI/alpha 1-proteinase inhibitor (alpha 1 PI) observed in these lavage samples was 0.7, which is generally higher than those derived from the data of other authors. This suggests that BMPI is a different protein to those previously described, although its exact relationship to other low molecular mass proteinase inhibitors remains to be determined.

Amino Acids↗
PubMed1985

Maternal attitudes to fetal monitoring.

During a randomized clinical trial concerning alternative methods of intrapartum fetal surveillance (electronic fetal monitoring (EFM) and auscultation (AUS)) an investigatory interview was carried out. Out of 655 expecting mothers the antepartum preference of EFM was 39.5%, of AUS 32.3% and 28.1% were undecided (UD). EFM was especially preferred by obstetrical high-risk patients. Reasons for preference of AUS were a natural childbirth, a non-technological milieu, and the lack of supposed discomfort from sensors and belts. The pregnant women found as major advantages of EFM continuous observation and the possibility of quick intervention. Postpartum 385 patients were again interviewed. The majority upheld the original preference if that method was used. If the non-preferred method had been applied many would stick to the primary preference although a tendency to prefer the experienced method was seen. The patients who antepartum preferred AUS, but had EFM, became more positive toward the method, and a significantly increased number were positively influenced by the EFM signal/trace and found the method promoting their partner's involvement in labor. Enforced immobility, however, was a major disadvantage as well as the technical milieu. If EFM is to be accepted by a majority of women giving birth it is necessary to increase the pregnant women's knowledge of the method and to take milieu factors into consideration in order to reduce the intrinsic depersonalization of EFM.

Adult↗
PubMed1985

Extracellular elastolytic activity in human lung lavage: a comparative study between smokers and non-smokers.

Unrestrained proteolysis in the lung is believed to initiate emphysema, a disease common among tobacco smokers. However, few studies have found extracellular protease activity in human lung lavage. In this investigation, elastase and serine protease activities were measured in bronchoalveolar lavage supernatants (BAL) from patients undergoing routine investigations. Significantly more elastolytic activity (against insoluble [3H]-elastin) was recovered in the lavage of smokers than that of non-smokers. However, no significant difference was found when the levels of serine proteolytic activity (against N-succinyl-L-trialanyl-p-nitroanilide) were compared. The elastolytic component of the protease activity rose from 5% in non-smokers' BAL to over 30% in that of smokers, suggesting that elastase activity is selectively enhanced by smoking. In lavages from most smokers, 80% or more of the elastase activity was serine-dependent, whereas lavages from non-smokers contained variable proportions of serine elastase. Both alpha 1-proteinase inhibitor (alpha 1-PI) and a low molecular weight antiprotease, bronchial mucus proteinase inhibitor (BMPI) were detectable in the lavage samples, the latter contributing up to 76% of the total antiprotease quantified in the lavage. Functional antiprotease was detected in 85% of the lavages. Since there were no differences in either antiprotease levels or functional inhibitory capacities between lavages from smokers and controls, it is concluded that the imbalance in the protease/antiprotease profile of the smokers' lung results from an enhancement of proteases, specifically of elastolytic activity, rather than a reduction in inhibitory capacity.

Adolescent↗
PubMed1984

Acoustic neuroma in a child treated with the aid of preoperative arterial embolization. Case report.

A child is described who presented with a large right vascular acoustic neuroma causing raised intracranial pressure and brain-stem compression. Ventriculoperitoneal shunting and arterial embolization were performed prior to total tumor excision. Acoustic neuromas are a rarity in childhood, and preoperative arterial embolization has infrequently been described as an adjunct to acoustic neuroma surgery.

Cerebral Arteries↗
PubMed1982

Trigeminal neuralgia and hemifacial spasm: treatment by microvascular decompression.

On the basis of observation of 26 patients, we consider that the common cause in trigeminal neuralgia and hemifacial spasm is compression of the nerve-root entry zone at the brainstem by a blood vessel, usually an artery. By mobilising the vessel, and securing it away from the nerve, symptoms were relieved in 16 of 17 patients with trigeminal neuralgia and in seven of nine patients with hemifacial spasm for a follow-up period of up to four years. Trigeminal microvascular decompression had few complications, but three patients treated for facial hemispasm had postoperative deafness and one had a probable small brainstem infarct. The major advantage of this surgical approach is that is possible to relieve the symptoms without facial anaesthesia or paralysis.

Adult↗
PubMed1977

Measurement of urinary and serous-fluid glycosaminoglycans and urinary hydroxyproline.

Although analytic measurements of connective tissue components in biological fluids would frequently be useful in diagnosis and/or management of many inflammatory, neoplastic and metabolic diseases, such information is often unavailable due to the methodologic problems posed by these natural products. This report outlines relatively simple procedures leading to the colorimetric measurement of glycosaminoglycans in urine and other body fluids and to measurement of hydroxyproline in urine. Normal values and potential applications are presented.

Ascitic Fluid↗
PubMed1977

Ultrasound evaluation of abdominal aortic aneurysms.

Forty-eight patients undergoing elective repair of an abdominal aortic aneurysm were randomly selected for correlation of diagnosis of aneurysm and aneurysm size as determined by direct surgical measurements, ultrasound examination, and lumbar spine X-ray. The preoperative diagnosis was confirmed by lumbar spine plain films in 72% of patients and by B-mode ultrasound in all of patients. Aneurysm size could be measured by lumbar spine X-ray in 55% of patients and with gray-scale B-mode ultrasound in all of patients. The average difference between surgically measured and roentogenographically determined aneurysm size was 1.5 cm in the transverse diameter and 0.87 cm in the anteroposterior diameter of the aneurysm. The average difference between surgically measured aneurysm size and ultrasound-determined external wall diameter of the aneurysm was 0.42 cm in the transverse diameter and 0.29 cm in the anteroposterior diameter. From these data we conclude that gray-scale B-mode ultrasound of the aorta is a more sensitive and accurate method of assessing abdominal aortic aneurysms than is the use of lumbar spine X-ray.

Aorta, Abdominal↗