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Biomedical subjects

I A Stewart

Publications and source records attributed to I A Stewart.

At least 19 recordsLinked to original sources
PubMed2001

Behaviour and developmental effects of otitis media with effusion into the teens.

OBJECTIVE: To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11-18 years). SETTING: Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study. PARTICIPANTS: Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9. MAIN OUTCOME MEASURES: Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years. RESULTS: After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years. CONCLUSIONS: No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens.

Acoustic Impedance Tests↗
PubMed2000

Molecular evidence for genetic mixing of Arctic and Antarctic subpolar populations of planktonic foraminifers.

Bipolarity, the presence of a species in the high latitudes separated by a gap in distribution across the tropics, is a well-known pattern of global species distribution. But the question of whether bipolar species have evolved independently at the poles since the establishment of the cold-water provinces 16-8 million years ago, or if genes have been transferred across the tropics since that time, has not been addressed. Here we examine genetic variation in the small subunit ribosomal RNA gene of three bipolar planktonic foraminiferal morphospecies. We identify at least one identical genotype in all three morphospecies in both the Arctic and Antarctic subpolar provinces, indicating that trans-tropical gene flow must have occurred. Our genetic analysis also reveals that foraminiferal morphospecies can consist of a complex of genetic types. Such occurrences of genetically distinct populations within one morphospecies may affect the use of planktonic foraminifers as a palaeoceanographic proxy for climate change and necessitate a reassessment of the species concept for the group.

Animals↗
PubMed1999

Evaluation of factors affecting outcome of surgery for otitis media with effusion in clinical practice.

In discussing surgery for otitis media with effusion (OME), tympanostomy tubes and adenoidectomy are important. Sinus surgery is less important and cleft palate surgery needs to be mentioned for completeness sake. There is no evidence supporting the value of tonsillectomy in the treatment of OME. Tympanostomy tubes are possibly best regarded as artificial eustachian tubes, which remain in position for a variable amount of time. It is therefore apparent that resolution of OME from tympanostomy tube placement largely depends on whether underlying aetiological factors have either resolved or been corrected when the tympanostomy tube was in position.

Adenoidectomy↗
PubMed1998

Mitochondrial A7445G mutation in two pedigrees with palmoplantar keratoderma and deafness.

A New Zealand and a Scottish pedigree with maternally inherited sensorineural deafness were both previously shown to carry a heteroplasmic A7445G mutation in the mitochondrial genome. More detailed clinical examination of the New Zealand family showed that the hearing loss was progressive, with the severity of the overall loss and the frequencies most affected differing markedly between individuals of similar age, and showed that many relatives also had palmoplantar keratoderma. Review of the literature demonstrated three other large families with presumed autosomal dominant inheritance of palmoplantar keratoderma and hearing loss. In a United Kingdom pedigree the syndrome was transmitted by female and male parents, an inheritance pattern which made mitochondrial inheritance unlikely; however, in a Turkish and a Japanese pedigree the affected individuals were all maternally related. Subsequent analysis of the Japanese pedigree documented the same A7445G mitochondrial mutation as was previously found in the New Zealand and Scottish pedigrees. Other mitochondrial sequence variants previously reported in the New Zealand or Scottish pedigrees were absent from the Japanese pedigree which suggests that the A7445G mutation arose independently in all three pedigrees. To our knowledge palmoplantar keratoderma has not previously been associated with mitochondrial defects; however, the current findings suggest that the A7445G mutation is associated not only with progressive hearing loss but also with palmoplantar keratoderma. The penetrance and expressivity of both symptoms varied considerably between individuals in the Scottish and New Zealand Studies which suggests that additional environmental and/or genetic factors are involved.

Adolescent↗
PubMed1998

Laryngeal rhabdomyosarcoma in adults.

Laryngeal rhabdomyosarcoma is a rare disease. Only nine of these tumours have been adequately described in world literature in the adult population. Adult patients with laryngeal rhabdomyosarcoma often present at a later stage than other laryngeal tumours, including squamous cell carcinoma. Diagnosis is made by identification of cross-striations histochemically or cytoplasmic myoglobin by immunohistological methods. We present a 66-year-old woman with pleomorphic rhabdomyosarcoma of her larynx. This is the first female in the adult age group to be presented. Surgical treatment with adjuvant radiotherapy is currently the treatment of choice for this disease. We provide a review of the literature on laryngeal rhabdomyosarcoma, including presentation, pathology and management of this rare disease.

Aged↗
PubMed1998

The prevalence of exostoses in the external auditory meatus of surfers.

Fifty-four surfers and 38 surf life savers were examined and questioned in order to determine the prevalence of exostoses. Seventy-three per cent had evidence of body exostoses in the external auditory meatus. Forty per cent had their ear canals narrowed by 50% or more. The relationship between the number of years spent surfing or life saving and the extent of canal stenosis was highly significant (P < 0.00001). Left and right ears were affected equally in this series and the obstruction appears to begin after approximately 7 years and is further aggravated by continued surfing. Over 90% of subjects who had participated for longer than 10 years had some evidence of exostoses. There was no significant association between the number of days per year or the number of hours per day spent surfing and the development of surfer's ear in this sample. Those who participated in their water sport over winter had significantly more exostoses than those who did not (P < 0.0001). Those who lived in the South Island (colder water) had more surfer's ear than those in the North Island (warmer water).

Adolescent↗
PubMed1996

Advanced head and neck cancer: proportionally higher in southland than Otago.

AIMS: To compare the proportion of advanced head and neck cancer presenting from Otago and Southland, and to discuss any differences observed. METHOD: Retrospective review of 186 patients resident in Otago and Southland who presented with a head and neck squamous cell carcinoma to the department of otolaryngology, Dunedin Hospital, between 1985-95. RESULTS: Otago patients had advanced disease in 43% of cases, compared to 66% in Southland patients (p = 0.004). Patients from rural Southland areas had advanced disease in 88% of cases. The incidence of cases was not significantly different between Otago and Southland. No difference was seen in local tumour size, however, Southland had a significantly higher rate of lymph node metastases (p = 0.0003). No difference was also seen in age, gender, duration of presenting symptoms, or delay in referral or diagnosis. CONCLUSIONS: Southland had a significantly higher proportion of advanced head and neck cancer than Otago. Significant differences in access to tertiary health care could not be found. The reasons for the differences observed were unclear.

Aged↗
PubMed1995

The contribution of the DFNB1 locus to neurosensory deafness in a Caucasian population.

Classical studies have demonstrated genetic heterogeneity for nonsyndromic autosomal recessive congenital neurosensory deafness, with at least six loci postulated. Linkage analysis in two consanguineous Tunisian kindreds has demonstrated that one such deafness locus, DFNB1, maps near chromosome 13 markers D13S175, D13S143, and D13S115. We tested these markers for cosegregation with deafness in 18 New Zealand and 1 Australian nonconsanguineous kindreds, each of which included at least two siblings with nonsyndromic presumed congenital sensorineural deafness and that had a pedigree structure consistent with autosomal recessive inheritance. When all families were combined, a peak two-point lod score of 2.547 (theta = .1) was obtained for D13S175, 0.780 (theta = .2) for D13S143, and 0.664 (theta = .3) for D13S115. While there was no statistically significant evidence for heterogeneity at any of the three loci tested, nine families showed cosegregation of marker haplotypes with deafness. These observations suggest that the DFNB1 locus may make an important contribution to autosomal recessive neurosensory deafness in a Caucasian population. In the nine cosegregating families, phenotypic variation was observed both within sibships (in four families), which indicates that variable expressivity characterizes some genotypes at the DFNB1 locus, and between generations (in two families), which suggests allelic heterogeneity.

Base Sequence↗
PubMed1994

Use of surgical stapling device in excision of pharyngeal diverticulum.

Pharyngeal diverticulum (Zenker's diverticulum, hypopharyngeal pouch) is an outpouching of pharyngeal mucosa through a triangular area of weakness between the lower oblique fibres of the inferior constrictor muscle and cricopharyngeus called Killian's dehiscence. Prescribed treatment in large pouches is excision of the diverticulum with or without cricopharyngeal myotomy. Experience of closure of the oesophageal defect with an automatic stapling device is presented in nine cases of pharyngeal diverticula. Previous reports describing this technique have included substantial delays in the resumption of oral intake and prolonged hospitalization. It is shown that these delays are unnecessary.

Aged↗
PubMed1992

Acute tonsillectomy in the management of infectious mononucleosis.

Life-threatening upper airway obstruction can be caused by tonsillopharyngitis secondary to infectious mononucleosis (IM). The administration of corticosteroids, emergency tracheostomy and acute tonsillectomy have been advocated as ways of managing this problem. In a series of 25 patients admitted over a five-year period with IM, 15 were judged to have symptoms severe enough to warrant the administration of corticosteroids. Six of these 15 patients had little improvement in their condition and thus underwent acute tonsillectomy. There were no significant complications of this surgery. A further three patients who received corticosteroids required tonsillectomy for recurrent tonsillitis later in the study period. By contrast, only one of the ten patients who did not receive corticosteroids subsequently required tonsillectomy. Acute tonsillectomy is of value in selected cases of IM tonsillopharyngitis. It may decrease the morbidity of recurrent tonsillitis after IM, in addition to averting the immediate risk of respiratory obstruction.

Acute Disease↗
PubMed1990

Acoustic reflectometry for assessment of hearing loss in children with middle ear effusion.

We sought associations between acoustic reflectometry and hearing loss in ears with and without middle ear effusion in 137 New Zealand children ages 3 to 16 years. Reflectometry was significantly associated with conductive hearing loss. These associations were present in the entire sample; correlation coefficients varied between 0.31 at 2000 Hz (P less than 0.001) and 0.55 for a three frequency pure tone average (P less than 0.001). The associations persisted for the sample of ears deemed to be filled entirely by effusion; correlation coefficients varied between 0.27 at 4000 Hz (P = 0.026) and 0.47 at 500 Hz (P less than 0.001). Using a reflectivity of 6.0 or greater to detect a three frequency pure tone average loss of 30 dB or more, the sensitivity was 88% and the specificity was 44%. The technique of acoustic reflectometry should be explored and extended to permit rational decisions about management of middle ear effusions.

Adolescent↗
PubMed1990

Computerized tomography mini-series: an alternative to standard paranasal sinus radiographs.

Computerized tomography (CT) imaging provides detailed information on the paranasal sinuses that is not available from standard radiographs. The planning and safety of endoscopic sinus surgery is greatly improved by CT imaging. Frequently standard radiographs are ordered because of the reduced cost. The four-slice CT Mini-series outlined in this paper provides high resolution bone and soft tissue imaging of the key surgical areas. The Mini-series comprises three precisely placed coronal slices and one axial slice. An average Mini-series takes 20 min to perform at a cost of $NZ66.00. Standard radiographs take up to 30 min to perform at a cost of $NZ38.00.

Endoscopy↗
PubMed1989

Lateral displacement of the intact mandibular condyle. Review of literature and report of case with associated facial nerve palsy.

A rare injury is described, in which symphyseal fracture of the mandible was associated with lateral displacement of the intact mandibular condyle into the temporal fossa and damage to the ipsilateral facial nerve with unilateral facial paralysis. Management of the injury was associated with an episode of acute laryngeal obstruction, necessitating emergency tracheostomy.

Adult↗
PubMed1988

Health in Niue.

Explore the source record for details and available documents.

Child↗
PubMed1988

Pharmacokinetics and sputum penetration of enoxacin after twice daily oral dosing for seven days.

The ability of enoxacin to penetrate into sputum and its distribution and elimination characteristics after dosing to steady state were determined in six subjects with permanent tracheostomies. At steady state the mean trough level of enoxacin in sputum was 1.75 +/- 0.70 mg/kg (mean +/- S.D.), and the corresponding level in plasma was 1.23 +/- 0.32 mg/l. The mean peak sputum concentration at steady state was 7.12 +/- 4.21 mg/kg with the corresponding level in plasma being 4.54 +/- 1.34 mg/l. The ratio of the mean trough concentration of enoxacin in sputum to that in plasma was 1.42 +/- 0.36, and the ratio of the mean peak concentrations was 1.67 +/- 1.07. The pharmacokinetics of enoxacin in sputum were similar to those in plasma, the only significant difference being between the mean times to reach peak concentration (T-max) which were 2.62 +/- 1.04 and 0.92 +/- 0.44 h in sputum and plasma respectively (P less than 0.01). After reaching steady state, the mean area under the plasma time-concentration curve (AUC) from 0 to 12 h (the dosing interval) was 26.6 +/- 5.9 mg/h/l, and the mean AUC (0-12) for sputum was 40.9 +/- 21.8 mg/h/kg. The mean apparent total clearance was 259.6 +/- 48.8 ml/min and the mean apparent volume of distribution was 169.6 +/- 30.51. Enoxacin exhibits a high degree of penetration into sputum which may prove useful in the treatment of bacterial infections of the respiratory tract.

Administration, Oral↗