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Biomedical subjects

R F Taylor

Publications and source records attributed to R F Taylor.

At least 19 recordsLinked to original sources
PubMed1992

Betel-nut chewing and asthma.

Two Asian patients admitted to hospital with acute severe asthma had been chewing betel nut immediately before the attacks. Arecoline, a cholinergic alkaloid, is a major constituent of Areca catechu (betel) nut and causes the euphoric effects. We sought an association between betel-nut chewing and bronchoconstriction in asthmatic patients. In vitro, arecoline caused dose-related contraction of human bronchial smooth-muscle strips, with one-tenth the potency of methacholine. In a double-blind challenge study, inhalation of arecoline caused bronchoconstriction in six of seven asthmatic patients and one of six healthy subjects; methacholine caused bronchoconstriction in all the asthmatic patients and in five controls. The geometric mean concentrations of arecoline and methacholine that caused 20% falls in the forced expiratory volume in 1 s (PC20 FEV1) in the asthmatic subjects were 5.2 mg/ml and 1.6 mg/ml, respectively. We then studied four Bengali asthmatic patients, regular users of betel nut, during a betel-nut challenge. Three showed no adverse effects, but one showed a 30% fall in FEV1 by 150 min after chewing; the effect was reproducible. In the UK, the rate of hospital admission for acute asthma is higher among Asians than among other groups in the population; betel-nut chewing may be one of several factors that affect asthma control and severity of attacks.

Adult↗
PubMed1992

Auxotrophy of Pseudomonas aeruginosa in cystic fibrosis.

Seventy-four of 403 (18.4%) sputum isolates of Pseudomonas aeruginosa from 49 of 136 (36.0%) adults with cystic fibrosis (CF) were auxotrophic mutants. Two of 11 (18.2%) isolates of P. aeruginosa taken from patients with non-CF bronchiectasis were also auxotrophic. All 99 strains taken from non-bronchiectatic sources were prototrophic. Forty-six of 55 (83.6%) CF auxotrophs required one or more of 36 growth factors tested; the requirements for the remaining 9 isolates were not identified. Methionine was the sole factor required by 17 of 22 (77.3%) isolated which depended on a single factor. We conclude that auxotrophy is a feature of P. aeruginosa infection in cystic fibrosis.

Amino Acids↗
PubMed1992

Pseudomonas cepacia pulmonary infection in adults with cystic fibrosis: is nosocomial acquisition occurring?

Ribotyping of 25 isolates of Pseudomonas cepacia taken from the sputum of 21 adults with cystic fibrosis (CF) who were registered at the Royal Brompton Hospital between 1987 and 1991, revealed that seven patients (33.3%) shared strains of a similar ribotype pattern with others, while 14 patients (63.7%) harboured strains unique to each individual. Constancy of sputum strain carriage was seen in two of three patients sampled twice over a 3-month period. Although no evidence for patient-to-patient transmission of P. cepacia within this group of patients was found, the fact that one third of CF patients shared strains of the same ribotype with others, suggests that nosocomial acquisition of this organism may have occurred.

Adolescent↗
PubMed1992

Temocillin and cystic fibrosis: outcome of intravenous administration in patients infected with Pseudomonas cepacia.

Twelve courses of intravenous temocillin were given in combination with an intravenous aminoglycoside to five patients with cystic fibrosis (CF) for pulmonary exacerbations associated with Pseudomonas cepacia. All patients were infected concurrently with Pseudomonas aeruginosa in addition to P. cepacia. Improvement occurred after six of seven courses given to three patients in which temocillin was used as first-line therapy and following three of five courses given to two patients after failure of other antipseudomonal agents. All ten pre-treatment isolates of P. cepacia were resistant to aminoglycosides and eight were sensitive to temocillin. Clinical improvement was seen on both occasions in which the pre-treatment isolates were resistant to temocillin.

Adolescent↗
PubMed1992

Extrapulmonary sites of Pseudomonas aeruginosa in adults with cystic fibrosis.

BACKGROUND: Pseudomonas aeruginosa infection is seldom eradicated in patients with cystic fibrosis despite intensive antipseudomonal treatment. Upper airway sites of infection may contribute to perpetuation of lower airways infection. This study was designed to find out which extrapulmonary sites are infected and whether the strains at these sites are identical to those in the lungs. METHODS: Sputum and upper airway samples from 42 patients were cultured for P aeruginosa and stool samples from 20 patients were also tested. Nineteen isolates from sputum and extrapulmonary sites from four patients were genotyped with the pCM tox probe. RESULTS: P aeruginosa was isolated from the sputum of 36 patients, 34 of whom had infection in the upper airways. Six of the 20 patients tested were positive for P aeruginosa in the stool. The nasopharynx was colonised in 30 patients, the oropharynx in 29, the middle meatus in 13, the external nares in six, and the inferior turbinate in four. Three of four patients tested had the same strain of P aeruginosa (a different one in each individual) in the sputum and the upper airways, and in two of the three the stool isolate was a different strain. CONCLUSION: Most adults with cystic fibrosis and P aeruginosa pulmonary infection have upper airway reservoirs of the organism and strains from these sites are identical to those in the lungs.

Adolescent↗
PubMed1991

Effect of heart-lung transplantation on airway potential difference in patients with and without cystic fibrosis.

Measurement of the potential difference (PD) across the airways provides an indication of the viability and integrity of the lining epithelium. PD was recorded from the lower airways in "diseased controls" and in patients following heart-lung transplantation. Diseased controls showed a high PD centrally which fell (became less negative) peripherally (trachea -15.8 mV (SEM 1.0), lobar bronchi -12.6 mV (1.2), segmental bronchi -9.8 mV (1.2]. Following heart-lung transplantation (HLT) the profile of PD with airway size was altered in comparison to non-transplanted patients with reduced values in the large airways. Host tracheal values above the anastomosis were similarly reduced. Two episodes of rejection were associated with a lower mean airway PD; no significant changes were found with infection. In patients with cystic fibrosis (CF), values in the donor lung did not differ from those in non-CF transplanted patients up to one year following transplantation, although nasal PD in the host remained elevated. HLT selectively alters the PD profile only of larger airways, which may relate to the interruption of the bronchial arterial supply to these sites.

Biological Transport, Active↗
PubMed1990

Specialized gastrointestinal units for the management of upper gastrointestinal haemorrhage.

In 1986, 292 patients were admitted to a joint medical-surgical gastrointestinal unit with upper gastrointestinal haemorrhage. Fourteen patients died (4.8%) a mortality considerably lower than recorded in most series. The low mortality may result from the use of a specialized gastrointestinal unit to which all patients with upper gastrointestinal haemorrhage are admitted and managed with strict protocols for resuscitation, transfusion and surgery.

Aged↗
PubMed1990

Chronic cervical spinal cord injury and autonomic hyperreflexia in rats.

Although it is well established that patients with cervical spinal cord injury are prone to acute, marked, hypertensive episodes, i.e., autonomic hyperreflexia, the specific mechanisms mediating this sometimes-fatal phenomenon are not completely understood. In this report, we describe the preparation and characterization of a rat model of chronic cervical spinal cord injury and autonomic hyperreflexia. Adult male Sprague-Dawley rats were chronically instrumented with arterial, venous, and gastric catheters. Beginning the first day after a complete cervical spinal transection (CST) and continuing for 1 wk, acute hypertensive responses to a modest increase of urinary bladder pressure (0-20 mmHg) were studied. Mean arterial pressure increased 25.9 +/- 4.8 mmHg during bladder distension the first day after CST. This response was not significantly different 3, 5, and 7 days after CST (overall average = 18.0 +/- 2.3 mmHg). The pressor response to bladder distension was completely abolished by intravesical lidocaine and autonomic ganglionic blockade (atropine + hexamethonium). Responses to bladder distension were not observed after the administration of chloralose anesthesia. We conclude that after cervical spinal transection the rat exhibits autonomic hyperreflexia similar to that seen in humans with spinal injury. Furthermore, autonomic hyperreflexia is completely established within 24 h after CST in the rat. Finally, some spinal autonomic reflexes are suppressed by chloralose anesthesia in the rat.

Animals↗
PubMed1989

The management of children born to human immunodeficiency virus seropositive women.

Increasing numbers of children born to human immunodeficiency virus (HIV) antibody-positive women are being identified, but guidelines as to their management are lacking. We have therefore established a paediatric counselling and screening clinic for managing such children in Edinburgh. During a period of 3 years, 49 infants and children of 43 HIV seropositive women have been seen. After a median follow-up period of 23 months, four children were found to have clinical evidence of HIV disease which was non-specific and could have been missed had they not been regularly monitored. Thus, close surveillance of infants born to seropositive women is important. Identifying a single clinic where this is done has allowed experience to accumulate on issues beyond the medical management of these infants as well as contributing to the clinical care of infants with symptoms. Based on this experience, we have developed guidelines for managing children born to HIV antibody-positive women.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Determinants of arterial pressure after chronic spinal transection in rats.

The present study was conducted to determine whether sympathetic vasoconstrictor activity is a determinant of mean arterial pressure (MAP) hours and days after cervical spinal transection (CST) in unanesthetized rats. MAP on the 2 days before CST was 107.2 +/- 3.6 and 103.3 +/- 3.0 mmHg, respectively, and fell to 77.7 +/- 1.1 mmHg on day 1 after CST. MAP returned to control levels over the course of the study and, by day 9 after CST, was not statistically different from control (98.6 +/- 3.4 mmHg). Neither autonomic ganglionic blockade nor alpha-adrenergic blockade affected MAP the 1st day after CST. Similarly, alpha-adrenergic blockade was without effect on days 3, 5, and 7 after CST. Administration of a vasopressin V1-antagonist had no effect on MAP on day 1 or day 8 after CST. However, blockade of angiotensin-converting enzyme with captopril decreased arterial pressure both on day 1 (-22.1 +/- 2.6 mmHg) and day 8 (-23.3 +/- 2.9 mmHg) after CST. We conclude that neither sympathetic nor vasopressin vasoconstrictor activity affected MAP within the 1st wk after CST. Although the vasoconstrictor actions of angiotensin II were important, these effects were not responsible for the normalization of MAP observed after CST.

Angiotensin II↗
PubMed1989

Airway complications from free-basing cocaine.

The majority of the deaths due to fires result from smoke inhalation, hypoxia, and systemic toxicity. Lower airway injury from chemical byproducts carried in the smoke is less frequent and thermal injury to the lower airways is a rare occurrence. We report a case of severe thermal injury to the conducting airways due to either inhalational injury or to intratracheal ignition of the ether vehicle used in free-basing cocaine resulting in severe reactive airways disease and tracheal stenosis requiring reconstructive surgery.

Adult↗
PubMed1988

Transcoronary platelet activation and consumption in coronary artery disease: studies at rest.

The platelet count(PC), plasma platelet factor 4 (PF4) and plasma beta-thromboglobulin(beta TG) have been measured in blood obtained from a peripheral vein, the aortic root and the coronary sinus in 7 patients with normal coronary arteries, 9 patients with lesser degrees of coronary artery disease(CAD) and in 13 patients with severe CAD under resting conditions. In each patient group values obtained in the peripheral venous blood were similar to those obtained in normal subjects. In each group values obtained in blood from the coronary sinus were similar to those obtained in blood from the coronary aortic root and in most instances these were similar to values obtained in peripheral venous blood. for example, in the 13 subjects with hemodynamically significant 3-vessel or 2-vessel CAD the mean values in blood from a peripheral vein, the aorta and the coronary sinus respectively were: PC-194, 205, and 208 x 10(9)/1; PF4-3.3, 3.7, and 3.5 ng/ml; and beta TG-15.5, 23.0 and 18.6 ng/ml. These findings provide no support for the occurrence of continuous platelet activation or platelet consumption in the coronary vessels or elsewhere in patients with stable CAD, under resting conditions, regardless of its severity.

Coronary Disease↗
PubMed1988

Sudden and unexpected death in horses and ponies: an analysis of 200 cases.

An analysis was made of the causes of death in horses and ponies over one year of age which died suddenly (Group 1) or were found dead but were considered normal when last seen (Group 2). There were 49 animals in Group 1. Thoroughbreds were overrepresented, but there were no ponies in this group. No cause of death was found in 30.6 per cent of cases and 16.3 per cent died from each of the following causes: haemorrhage in the respiratory system, central nervous system, and adverse drug reactions. Cardiovascular lesions were the cause of death in 14.4 per cent and the remaining 3.1 per cent had lesions of the gastrointestinal system. Racehorses mostly died suddenly from severe haemorrhage in various sites, particularly the thorax. In Group 2 there were 151 animals, and in 33.1 per cent no cause of death was determined. Gastrointestinal lesions were considered the cause of death in 39.2 per cent of cases and respiratory lesions killed 8.6 per cent. Lesions of both the central nervous system and cardiovascular system were considered the cause in 4.6 per cent of cases. The remaining 9.9 per cent of animals had miscellaneous lesions. Toxicological studies were performed in 46 of the total 200 cases, and only two had positive results; lead in one and nicotine in the other.

Age Factors↗