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Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 649 records · Page 36Linked to original sources

The care of our children in everyday life.

The life within a family of a Rett syndrome child is usually in a constant state of changing emotion due to the overwhelming responsibility of caring for the afflicted child and meeting the needs of the remaining family. Personal philosophy and care techniques are related to give insight into one family's mixed blessing of having a Rett syndrome daughter and their struggle to maintain some normalcy within the seemingly incomprehensible malady. When families share with each other and with those who provide medical, educational and therapeutic care for their daughters, progress is made through mutual understanding and consideration for all persons involved, not the least of whom is the Rett syndrome child and her family.

Activities of Daily Living↗

The relationship between the density of Fasciola hepatica miracidia and the net rate of miracidial infections in Lymnaea truncatula.

Experimental studies on the dynamics of infection of Lymnaea truncatula by the miracidia of Fasciola hepatica show that there is a linear relationship between the net rate of attachment of miracidia to snail epithelium and the density of infective stages. The probability of a snail remaining uninfected after exposure to a single miracidium varies with the size class of the snail. Under the conditions of the experiment (temperature, 15 degrees C; exposure period, 30 min; water volume, 8 ml), the probability was 0.46-0.48, 0.27-0.26 and 0.13-0.19 for snail size classes, 0.5-2.9, 3.0-5.9 and 6.0-8.9 mm respectively.

Animals↗

The regulation of Ostertagia ostertagi populations in calves: the effect of past and current experience of infection on proportional establishment and parasite survival.

A mathematical model of the parasitic phase of the life-cycle of Ostertagia ostertagi in calves is described. The model is used in the re-analysis of previously published data from a long-term trickle infection experiment in which groups of calves were infected daily with graded doses of 3rd-stage (L3) larvae. The results of the analysis are consistent with the hypothesis that the observed changes in the intensity of infection in the calves were the result of a decline in the proportional establishment of ingested L3 larvae, and a rise in the death rate of the 5th-stage worms as the duration of exposure to infection increased. The proportion of ingested L3 larvae that become established in the mucosa can be described as an exponential decay function of the duration of the infection. Within the range of trickle intensities investigated, the function appears to vary independently of the level of exposure to infection. In contrast, the rate of mortality of the 5th-stage worms appears to be an increasing linear function of the total cumulative number of 3rd-stage larvae administered.

Animals↗

The regulation of Ostertagia ostertagi populations in calves: density-dependent control of fecundity.

The decline in faecal egg counts, characteristic of calves which have been experimentally infected with Ostertagia ostertagi, is analysed using a mathematical model in which parasite fecundity is assumed to be an inverse function of both the duration and intensity of infection. The model incorporates a description of the frequency distribution of mature parasites between hosts (which is less over-dispersed than is usual for many other helminth infections). The model provides a good overall description of the decline in faecal egg production observed during trickle and single infection experiments. The main discrepancy between a comparison of the model predictions and the results of the most detailed available series of trickle infection experiments occurs at the initial peak of egg production. The magnitude of this difference appears to be related to the worm burden at the peak of egg production. The possible mechanisms underlying density-dependent regulation of the fecundity of O. ostertagia are discussed.

Animals↗

A mathematical model of the population biology of Ostertagia ostertagi in calves and yearlings.

A mathematical model of the population biology of Ostertagia ostertagi is described. The model assumes that the natural control and regulation of parasite numbers is mediated by four processes: the effect of climate on the development and survival of the free-living stages; changes in the rate of establishment of the infective larvae, and density-dependent variations in parasite survival and fecundity. The model is used to compare the course of the infection in two groups of calves. One group is assumed to have been reared under conditions typical of S.E. England and the other under conditions typical of Louisiana, USA. The more general behaviour of the model is discussed in the context of sensitivity analysis. The model is an excellent mimic of the epidemiology of bovine ostertagiasis. It can be used as a simple screening procedure to help determine which of many possible anthelmintic control strategies should be selected for more detailed examination in the field, and it provides a theoretical framework within which ideas concerning the epidemiology of parasitic gastroenteritis can be assessed and refined.

Animals↗

Population biology of Ostertagia ostertagi and anthelmintic strategies against ostertagiasis in calves.

Five chemoprophylactic or chemotherapeutic strategies against bovine ostertagiasis are compared using a mathematical model of the population biology of Ostertagia ostertagi. The model offers a means of screening novel strategies prior to their further investigation in the field. Under conditions of climate and management typical of many regions in Northern temperate Europe, the model indicates that all of the tested prophylactic strategies will result in a profound reduction in the intensity of infection in grazing beef calves when compared with an untreated control group or the simple therapeutic protocol. Not all of those strategies which caused diminution in the scale of the midsummer rise in pasture larval contamination resulted in progressively less contaminated pastures in subsequent years. Moreover, the reproductive potential of the parasite is so great that the principal advantage of the 'pasture cleaning' effect that is the consequence of some protocols is not that the pasture may eventually be used to graze untreated calves but that the treated animals are subjected to a progressively smaller parasitic challenge with the concomitant pay-off in production gains.

Animals↗

Cardiovascular and catecholamine responses to laryngoscopy with and without tracheal intubation.

The catecholamine and cardiovascular responses to laryngoscopy alone have been compared with those following laryngoscopy and intubation in 24 patients allocated randomly to each group. Following induction with fentanyl and thiopentone, atracurium was administered and artificial ventilation undertaken via a face mask for 2 min with 67% nitrous oxide in oxygen. Following laryngoscopy, the vocal cords were visualized for 10 s. In one group of patients, ventilation was then re-instituted via a face mask, while in the second group the trachea was intubated during the 10-s period and ventilation of the lungs maintained. Arterial pressure, heart rate and plasma noradrenaline and adrenaline concentrations were measured before and after induction and at 1, 3 and 5 min after laryngoscopy. There were significant and similar increases in arterial pressure and circulating catecholamine concentrations following laryngoscopy with or without intubation. Intubation, however, was associated with significant increases in heart rate which did not occur in the laryngoscopy-only group.

Adult↗

Effect of topical lignocaine on the sympathoadrenal responses to tracheal intubation.

The catecholamine and cardiovascular responses to laryngoscopy and tracheal intubation have been studied in 30 patients undergoing elective gynaecological surgery, allocated randomly to one of three groups: group 1 received 4% lignocaine 160 mg using a Forrester Spray; group 2 received 4% lignocaine 160 mg by "Laryng-o-jet"; group 3 received an equal volume of saline administered by Forrester Spray. In all three groups, there were similar and statistically significant increases in mean arterial pressure and plasma adrenaline and noradrenaline concentrations 1 min after intubation, with diminution of these responses by 5 min after intubation. There were no differences between the three groups at any stage, which suggests that topical anaesthesia of the mucosa of the upper airway, as performed conventionally, is ineffective as a means of ameliorating the pressor and catecholamine responses to routine laryngoscopy and intubation.

Adult↗

Comparison of the Leicester Micropalliator and the Cardiff Palliator in the relief of postoperative pain.

Two devices for providing patient-controlled, on-demand analgesia were compared for 24 h after abdominal surgery. The Leicester Micropalliator delivered a mandatory background infusion of 1 mg h-1 in addition to on demand bolus doses of morphine 2 mg i.v. while the Cardiff Palliator provided only bolus doses of morphine 2 mg i.v. The Leicester Micropalliator provided analgesia superior or equivalent to that of the Cardiff Palliator in patients who had undergone hysterectomy or cholecystectomy, respectively, and there was no increase in side effects. The total doses of morphine administered over 24 h did not differ significantly between the two devices.

Adult↗

Evaluation of the combined effects of glycopyrrolate and neostigmine on the lower oesophageal sphincter.

The effects on the lower oesophageal sphincter (LOS) of the simultaneous administration of glycopyrrolate 0.5 mg and neostigmine 2.5 mg, when given to antagonize neuromuscular blockade, were studied in 10 healthy patients undergoing gynaecological surgery. LOS pressure and gastric pressure (GP) were measured for 20 min after the administration of the drug combination and barrier pressure (BrP) was calculated (LOS-GP). There was a significant reduction in BrP which lasted, in some patients, for the duration of the study. These results contrast with those of a similar study looking at the effects of atropine and neostigmine in which the decrease in BrP, although significant, was transient, and in which control values were regained after 5 min.

Drug Evaluation↗

Effects of alfentanil on the pressor and catecholamine responses to tracheal intubation.

The effects of alfentanil (given during induction of anaesthesia) on the haemodynamic and catecholamine responses to tracheal intubation were studied in 44 adult patients who received alfentanil 10 micrograms kg-1 or 40 micrograms kg-1, or saline placebo. Alfentanil 10 micrograms kg-1 and 40 micrograms kg-1 prevented any increase in heart rate and arterial pressure after tracheal intubation. Alfentanil 40 micrograms kg-1 produced profound hypotension and bradycardia. The use of alfentanil in both doses was associated with a decrease in plasma adrenaline concentrations after tracheal intubation.

Aged↗

A review of studies of anaesthetic risk, morbidity and mortality.

In the past two to three decades, advancing knowledge in the areas of physiology, pharmacology and scientific technology have allowed diversification from the purely technical aspects of administration of anaesthesia towards more accurate assessment of outcome for the individual in terms of both anaesthetic-induced morbidity and mortality. In addition, elucidation of the aetiology of the morbidity and mortality produced by anaesthesia, as opposed to that from surgery or concomitant medical or surgical disease processes, is assuming increased importance as a result of the expansion in medical litigation, where anaesthetists find themselves amongst the higher risk specialties in medicine. The morbidity produced by anaesthesia is relatively easy to define for specific populations, but the prediction of risk in an isolated individual remains elusive. For example, there are many studies indicating the incidence of postoperative myocardial infarction following surgical procedures in defined groups; but for the individual patient, more sophisticated risk assessments have so far failed to predict more accurately than the well-established ASA grading system. Nonetheless, it is expected that in future, studies in this area will permit increased precision in the assessment of risk, thereby permitting better consideration by both surgeon and patient of the options available regarding surgical and non-surgical therapy. Increasing emphasis on the safer administration of anaesthesia has been greatly aided by the use of the critical incident technique. By assessing near-misses in addition to existing morbidity and mortality, the technique increases the size and extent of the database, and by removal of the reticence inherent in an anaesthetist's confession of his mistakes, it increases the reporting of potential mishaps. Amongst the useful findings to have emerged from such studies is the previously unforeseen and unsuspected observation that the most dangerous period of anaesthesia is not during induction and recovery, but during the maintenance period. However, perhaps one of the more valuable aspects of this type of methodology is its potential use in quality control and audit within departments. There are undoubted problems and universally acknowledged difficulties in epidemiological research into anaesthetic mortality. Comparison of data between studies is rendered difficult owing to variations in procedure, including its prospective or retrospective nature, the definition of death, the perioperative time period studied, and the patient and hospital populations encompassed.(ABSTRACT TRUNCATED AT 400 WORDS)

Anesthesia↗

Arterial oxygen desaturation during postoperative transportation: the influence of operation site.

Arterial oxygen saturation in 132 patients was measured using a Biox IV oximeter with an ear probe, during transfer from theatre to recovery room following a variety of surgical procedures. Oxygen saturation decreased to 85% or less in 21.9% of patients and to 90% or less in 61.4%. No predictive factors were identified. It is recommended that supplementary oxygen be given to all patients in the immediate postoperative period, including the period of transit to the recovery room.

Adolescent↗

Indications for investigation of post-micturition dribble in young adults.

The endoscopic and urodynamic findings in eight male patients in whom post-micturition urinary dribble (PMD) was either the sole or predominant urinary symptom have been reviewed. In three patients whose only symptom was PMD, both endoscopic and videocystometric examinations were normal. In the remaining five patients with additional urinary symptoms, a functional or anatomical abnormality of the lower urinary tract was found in every patient. We conclude that in the assessment of patients with PMD, endoscopic and/or urodynamic investigation is of value only in those patients with multiple urinary symptoms.

Adolescent↗

Do normal mucosal biopsies predict prognosis in patients with transitional cell carcinoma of bladder treated by radical radiotherapy?

A biopsy of normal-looking mucosa showed mucosal abnormalities in 48.9% of patients with transitional cell carcinoma of the bladder. The presence of dysplasia or carcinoma in situ was significantly associated with grade but not with tumour category. In 100 patients who completed a course of radical megavoltage X-ray therapy, the result of mucosal biopsy gave no significant prognostic information about tumour regression, durable local control, survival or the risk of subsequent metastases.

Biopsy↗

Antibiotic prophylaxis for prostatic surgery. Single-dose cephradine compared with single-dose cefotaxime.

Several previous studies have attested to the value of antibiotic prophylaxis for prostatic surgery. We report a prospective randomised study which compared a single dose of cefotaxime with a single dose of cephradine given with the induction of anaesthesia. There was little difference between these regimens and it was concluded that either may be used, depending on availability and cost of the antibiotic. We have now completed a 5-year study of antibiotic prophylaxis for prostatic surgery and we also report the results of a long-term survey of the ward flora. There has been no significant change and there is no evidence for the emergence of resistant strains.

Aged↗

Local immune responses after intravesical BCG treatment for carcinoma in situ.

The lymphoid cellular infiltrates in the bladder biopsies from patients with carcinoma in situ before and after BCG intravesical therapy have been determined and characterised. This has been achieved using a panel of monoclonal antibody probes in an indirect immunoperoxidase technique. These studies have revealed the predominance of T-cells of the helper/inducer phenotype (T4+), beta-lymphocytes (B1+) and macrophages (Leu M3+, 3.9+) in bladder biopsies after BCG therapy. HLA.DR antigens were also expressed on the lymphoid cells infiltrate as well as the urothelial cells. These results suggest that the components of an active immune response were present and enhanced in the bladder wall after BCG therapy.

Administration, Intravesical↗