Biomedical subjects

C A Prescott

Publications and source records attributed to C A Prescott.

8 recordsLinked to original sources

PubMed1992

Peristomal complications of paediatric tracheostomy.

Failure of decannulation after paediatric tracheostomy, once the underlying disorder has resolved, is almost always due to peristomal complications. Granulation tissue formation in the raw tissue of the stoma and its subsequent fibrosis requires removal (50 of the 293 tracheostomies from the Red Cross War Memorial Children's Hospital). It is suggested that this can be avoided by creating a formal skin-to-trachea stoma at the time of tracheostomy. Suprastomal depression of the anterior wall of the trachea (52/293) appears to be unavoidable when using standard tracheostomy tubes. Localised stomal site tracheomalacia and stenosis (numbers of this complication are unknown) results from damage to cartilage of the trachea either by incision or by necrosis from pressure of the tracheostomy tube. Trauma to the cartilage needs to be minimised by careful design of the tracheal incision. It is suggested that consideration should be given to creating a formal tracheostomy stoma for any paediatric tracheostomy that is likely to be required for more than a short period of time.

Bronchiolitis↗

PubMed1992

Adenoids: comparison of radiological assessment methods with clinical and endoscopic findings.

Methods of evaluating adenoidal size pre-operatively are controversial. Symptoms and clinical evaluation have been both advocated and condemned. Depending on the methodology, measurement of the radiological adenoidal shadow has been difficult to correlate with the clinical patency of the nasopharyngeal airway and to the actual size of the removed adenoid. Four different methods were used to measure the adenoidal size on 74 radiographs. The methods were evaluated against the degree to which the adenoids obstructed the nasopharynx on flexible endoscopy of the postnasal space. Obstructive symptomatology was also evaluated against the degree of obstruction. The radiological method that best correlated to the endoscopic findings was that of Cohen and Konak (1985). However, obstructive symptomatology had the overall highest correlation to endoscopic findings.

Adenoids↗

PubMed1991

The effect of experimental infection with Rhodococcus equi on immunodeficient mice.

To investigate the pathogenesis of respiratory lesions caused by the facultative intracellular pathogen, Rhodococcus equi, pulmonary clearance was compared in four groups of genetically defined mice, chosen for their specific deficits in immune and inflammatory responses. Complement-deficient A/J, immunodeficient nu/nu (nude), scid/scid.bg/bg (SCID/beige), C57BI/6J.bg/bg (beige) and normal Swiss mice (SW) received approximately 10(7) R. equi intranasally on day 0. Bacterial clearance was assessed in lung, liver and spleen on days 1, 4, 7 and 14. Pulmonary clearance was not significantly different between SW and A/J mice. Beige mice cleared R. equi more rapidly and completely than A/J and SW, indicating that deficits in phagocytic and NK cell function associated with the bg/bg gene did not compromise clearance. Pulmonary clearance in immunodeficient SCID/beige mice paralleled that of the SW and A/J mice initially but bacterial proliferation produced significant differences from SW mice at day 14. Nude mice were unable to clear R. equi from day 1, resulting in the death of two nude mice at day 11. Both SCID/beige and nude mice developed severe pyogranulomatous bronchopneumonia, whereas A/J and SW mice developed transient pulmonary lesions. Beige mice developed minimal lung lesions. Significant systemic bacterial proliferation occurred only in nude and SCID/beige mice. We conclude that deficiencies in complement components, phagocytic and NK cells do not impair the pulmonary clearance of R. equi but that a competent cellular immune system is required to prevent pneumonia and death. The difference in early phase pulmonary clearance in nude and SCID/beige mice indicates two phases are important for clearance. An acapsular mutant of R. equi was completely cleared from the lungs of SCID/beige mice suggesting an important role for the capsule in virulence for mice.

Actinomycetales Infections↗

PubMed1991

Ear and hearing disorders in rural grade 2 (Sub B) schoolchildren in the western Cape.

Four hundred and one children living in rural areas with a high level of poverty were assessed for ear and hearing disorders in their second year of schooling. Overall, only 40.3% of these children had both normal-appearing ear drums and normal hearing thresholds bilaterally; 14% had obstructing wax plugs; 17% had evidence of past acute otitis media with scarring or progression to chronicity--6% having perforations; 31% had middle-ear effusions and/or their sequelae; and 33% had some impairment of hearing but, if the effect of testing in the classroom environment is considered, there was probably only significant impairment in 9%. It is suggested that the prevalence of chronic ear disorders is a useful marker of the quality of primary care in rural communities.

Adolescent↗

PubMed1991

Tympanoplasty surgery at the Red Cross War Memorial Children's Hospital 1986-1988.

Results of tympanoplasty surgery over a 3 year period in 96 children aged 2-12 years were analysed to better define indications for surgery and prognostic factors. Nineteen percent had a hearing loss associated with a dry perforation--grafts were successful in 84% and 71% improved hearing to less than 20 dB. Forty-two percent had a hearing loss but also troublesome recurrent infection--grafts were successful in 88% but only 65% improved hearing to less than 20 dB. Thirteen percent had troublesome recurrent infection--grafts were successful in 79%. Twenty-two percent had uncontrolled infection, a cortical mastoidectomy together with myringoplasty produced a 75% take rate. Graft take was not affected by age, type of surgery, infection status or perforation size. Poor nutritional status and postoperative infection both had negative tendencies. In this small series there was a 10% re-perforation rate.

Age Factors↗

PubMed1991

Mastoid surgery at the Red Cross War Memorial Children's Hospital 1986-1988.

Eighty-three children between ages 0-12 years had mastoid surgery in the three year period 1986-88. The indications were acute mastoiditis (30 children), uncontrolled chronic suppurative otitis media (CSOM) (24 children), cholesteatoma (22 children) and a miscellaneous group (7 children). Forty-seven per cent of those with acute mastoiditis were under one year but the 27 per cent with cholesteatoma as the precipitating cause were 4-12 years. Twenty-three per cent had significant complications. Typmano-mastoid surgery was employed to resolve uncontrolled CSOM. Children were between 2-12 years and 62 per cent were below the 25th centile for weight. Seventy-nine per cent of the tympanic membrane grafts were successful. The children with cholesteatoma were between 3-12 years and 76 per cent were below the 25th centile for weight. Eight of them only presented after the onset of acute mastoiditis. One child had a definite congenital cholesteatoma. Only one had a pars flaccida origin of the cholesteatoma sac and only eight an origin from the postero-superior pars tensa. All had open cavity surgery. When the cavity was lined by temporalis fascia, healing was improved markedly.

Acute Disease↗

PubMedDate not supplied

The current status of corrective surgery for laryngomalacia.

When the airway obstruction related to laryngomalacia becomes significant, surgical correction of the underlying laryngeal deformity is indicated. The three elements of the supraglottic soft tissue that prolapses, namely, the corniculate mounds on the arytenoid cartilages, the shortened ary-epiglottic folds, and the omega shaped epiglottis, can all be appropriately "trimmed" using either conventional instruments or the surgical laser. Relief of symptoms is dramatic and, provided surgery is performed precisely and not during episodes of infection, complications should not occur. The aid of specialized, skillful anesthesia is required for this type of surgery. We present a series of 40 children with significant obstruction: 30% had neuromuscular disorders, 68% had an infantile epiglottis, seven required airway support prior to surgery, all had laser "supraglottic trimming," and 13 required airway support after surgery. Relief of stridor and airway obstruction was generally rapid. There was only one complication: croup developing 4 days after surgery.

Child, Preschool↗

PubMedDate not supplied

Age-based construct validation using structural equation modeling.

In this paper we describe some mathematical and statistical models based on structural equation modeling (SEM) using computer programs like LISREL. We focus on SEM methodology for the simultaneous examination of the internal validity of psychological constructs and the external validity represented by age relations. To illustrate these ideas we use a latent variable path model to examine the organization of intellectual abilities measured by the WAIS-R in the standardization sample. We also examine different ways in which age can be used to structure this organization. This is primarily a methodological paper, but we try to integrate conceptual principles of modeling with some substantive issues of research on the psychology of aging.

Aging↗