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Biomedical subjects

J Wheatley

Publications and source records attributed to J Wheatley.

At least 19 recordsLinked to original sources
PubMed2005

Sensitivity of human gamma interferon assay and tuberculin skin testing for detecting infection with Mycobacterium tuberculosis in patients with culture positive tuberculosis.

SETTING: Nine university-affiliated chest clinics in Australia. OBJECTIVE: To evaluate the sensitivity of a whole blood human gamma-interferon assay (HGIA, QuantiFERON-TB) for specific T lymphocyte responses and Tuberculin skin testing (TST) for the detection of Mycobacterium tuberculosis infection in subjects with culture-proven M. tuberculosis disease (TBCP). DESIGN: Prospective testing of 129 patients with recent TBCP and 100 patients with non-tuberculosis lung disease (NTBLD). RESULTS: Using a defined level of specific IFN-gamma production and TST 10mm as positive cut-offs, the sensitivity of HGIA was 81% compared to 89% for TST (p=0.06). When positive responses in both TST and HGIA were combined, 96% of TB patients were detected. For the NTBLD group, 43% of whom were born overseas, 73% were negative for both the HGIA and TST. Prior immunization with M. bovis (bacille Calmette-Guerin) (BCG) or the type of TB had no effect on the sensitivities of the assays. For those treated for <2 months, the sensitivities for both assays were 84%, but for those treated for >2 months the sensitivity of TST (90%) tended to be higher than for HGIA (81%) (p=0.07). The distribution of TST results in TB patients showed a broad peak between 10 and 25 mm, while the results in the HGIA were bimodal in both TB and NTBLD patients. CONCLUSION: HGIA may prove an alternative to skin testing for detecting M. tuberculosis infection in certain settings.

Adult↗
PubMed2000

Influence of intra-oral maxillary sports mouthguards on the airflow dynamics of oral breathing.

PURPOSE: Mouthguards worn during sporting competition may influence oral airway flow dynamics and potentially increase airflow resistance during mouth breathing. METHODS: We measured oral airflow resistance (RO) in 10 normal subjects (four men, six women, age 29 +/- 3 yr, mean +/- SEM) wearing two different custom-made maxillary mouthguards. RESULTS: During tidal mouthpiece breathing (jaw position controlled), inspiratory R(O) (at (1.4 L x s(-1)) increased from 0.22 (0.15-0.46) cm H2O x L(-1) x s(-1) (median and interquartile range) to 0.47 (0.24-0.52) cm H2O x L(-1) x s(-1) with mouthguard 1 (general sports mouthguard) and from 0.34 (0.27-0.51) to 0.46 (0.39-0.86) cm H2O x L(-1) x s(-1) (N = 8) with mouthguard 2 (laminated, field hockey mouthguard, both P < 0.05). With oral only mask breathing (jaw position not controlled), inspiratory R(O) (at 0.4 L x s(-1)) increased to 1.02 (0.42-1.57) cm H2O x L(-1) x s(-1) (P < 0.03, compared with mouthpiece) but was variably affected by both mouthguards. At 1.0 L x s(-1), there was a tendency for both mouthguards to increase inspiratory R(O); however, this effect only reached significance for mouthguard 1 during mouthpiece breathing. CONCLUSION: Thus, although maxillary mouthguards do increase R(O) when jaw position is controlled, individual subjects respond differently when in control of mouth opening. This may be related to variable recruitment of compensatory mechanisms (e.g. mouth opening and/or oral airway dilator muscle activity).

Adult↗
PubMed1999

Community care. Home service.

A nurse-led scheme to prevent hospital admissions by providing emergency services in the community for up to 72 hours cared for 155 people in its first six months. The scheme operated well below full capacity partly because of initial opposition from GPs. The mean age of service users was 79 and the main reasons for referral were chest infections, pneumonia and the need for support following an injury. More than three quarters of those cared for were fit to be discharged from the scheme within 72 hours.

Aged↗
PubMed1997

Co-occurrence of executive impairment and amnesic syndrome following sub arachnoid haemorrhage: a case study.

This case study presents a 37 year old man, P.P., who shows evidence of both profound executive impairment and diencephalic amnesia associated with two discrete lesion sites following a Sub Arachnoid Haemorrhage. The executive impairment is unusual in type and severity, amounting to a gross impairment in the initiation and organisation of action. The thalamic lesion provides a rare example of diencephalic damage resulting in an extensive retrograde amnesia of the type that is often associated with Korsakoff's syndrome, but which in this case is not associated with prolonged alcohol abuse. Some of the problems caused by the co-occurrence of two such profound and disabling impairments are discussed.

Adult↗
PubMed1994

Respiratory-related activity of soft palate muscles: augmentation by negative upper airway pressure.

We studied respiratory-related activity of the soft palate muscles in 10 anesthetized tracheostomized supine dogs. Moving time average (MTA) electromyographic (EMG) activity was measured in the palatinus (PAL), levator veli palatini (LP), and tensor veli palatini (TP) with bipolar fine-wire electrodes and in the diaphragm with bipolar hook electrodes. Measurements were made during tracheostomy breathing and nasal breathing with the mouth sealed (NB). During tracheostomy breathing, all soft palate muscles displayed respiratory-related phasic inspiratory and expiratory as well as tonic EMG activity. During NB, peak inspiratory EMG activity increased in PAL, LP, and TP because of an increase in both phasic inspiratory and tonic MTA activity. In contrast, phasic expiratory activity did not change. A constant negative pressure equal to peak inspiratory tracheal pressure during NB was applied to the caudal end of the isolated upper airway with the nose occluded. This was associated with soft palate muscle responses qualitatively similar to the responses during NB but accounted for only 39, 25, and 32% of the magnitude of the peak inspiratory MTA EMG responses to NB in PAL, LP, and TP, respectively. Our results demonstrate that the soft palate muscles exhibit respiratory-related activity in common with other upper airway muscles. Furthermore, such activity is augmented in each soft palate muscle during NB, and negative upper airway pressure makes a substantial contribution to the recruitment of soft palate muscle activity.

Anesthesia↗
PubMed1994

Soft palate muscle activity in response to hypoxic hypercapnia.

We studied the effects of increasing respiratory drive on electromyographic (EMG) soft palate muscle (SPM) activity in nine anesthetized tracheostomy-breathing dogs during hypoxic hypercapnia (HH) with a 14% O2-8% CO2-78% N2 inspired gas mixture. Moving time average EMG activity was recorded from palatinus (PAL), levator veli palatini (LP), and tensor veli palatini (TP) muscles (with bipolar fine-wire electrodes) and diaphragm (DIA; with bipolar hook electrodes). During HH, peak inspiratory DIA activity increased from 18.8 +/- 1.3 to 30.1 +/- 2.0 arbitrary units and minute ventilation increased from 6.2 +/- 0.3 to 18.3 +/- 1.8 l/min (both P < 0.001). Phasic inspiratory, expiratory, and/or tonic EMG activity was present in each SPM during room air breathing (control) and increased during HH (P < 0.05), except for phasic inspiratory PAL and phasic expiratory TP activities. Peak inspiratory LP and TP activities increased during HH to 250 and 179% of control, respectively, and peak expiratory activity increased to 187, 235, and 181% of control in PAL, LP, and TP, respectively. These findings demonstrate respiratory-related regulation of SPM activity independent of local reflex control from the upper airway. However, the combined inspiratory and expiratory phasic recruitment of these muscles differs from the inspiratory recruitment of known upper airway dilator muscles.

Animals↗
PubMed1990

Paediatric post-injury management: a hospital-based review of deaths.

In order to begin to evaluate the need for an integrated trauma management service for injured children, a retrospective review of deaths following admission to a suburban teaching hospital was conducted. The medical records and coroners' reports for 64 consecutive cases over 68 months were reviewed, looking for errors in care which may have contributed to fatal outcomes. There was a male predominance (64%). The main causes of death were pedestrian injuries (42%), drownings (20%), injuries to vehicular passengers (17%) and injuries to cyclists (13%). Errors, often multiple, occurred in 29 cases (45%). Errors most frequently involved airway control and ventilatory support (25%), volume replacement (19%) and delays in performing essential investigations (13%). Errors were most frequent at the referring hospitals (49% [17 of/35 referred cases], compared with 14% at the teaching hospital), and principally involved multiply injured victims of blunt trauma (81%, 13 of 16 patients). In only three cases (5%) would better management have salvaged the patient. This can be explained partly by the predominance of what were judged to be irretrievable intracranial injuries (90%) in patients suffering blunt injuries. In contrast, an analysis of the same patient group revealed that in 30-50% the fatality could have been prevented by the full application of well recognized safety strategies. While strategies such as triage and trauma teams should reduce the error rate, it is yet to be proven that optimal post-injury care will significantly reduce mortality.

Adolescent↗
PubMed1989

Traumatic deaths in children: the importance of prevention.

In order to determine the preventable factors in fatal accidents, a retrospective review of paediatric deaths after admission to a suburban teaching hospital was conducted. The medical records and coroners' reports for 64 consecutive cases over a 68-month period were reviewed. The main causes of death were pedestrian injuries (42% of deaths), drowning (20% of deaths) and injuries to vehicular passengers (17% of deaths) and cyclists (13% of deaths). There was a male predominance (64%). Children who were aged less than five years were at greatest risk at home, with death by drowning (46% of deaths) predominating. For children who were over five years of age, accidents on the roadway as pedestrians (58% of deaths) and pedal-cyclists (20% of deaths) were the most-common causes of death. Analysis of the accidents showed that preventive strategies were underutilized. Thirty per cent of deaths could have been avoided by the wearing of restraints in motor vehicles, the wearing of cycle-helmets and the proper use of swimming-pool barrier equipment. Adequate supervision of children who were less than 10 years of age at road crossings could have prevented a further 17% of deaths. In comparison, even the most-optimal postinjury care would have salvaged only 5% of the cases. Therefore, while the ideal organization of services after injury is a logical aim in the management of childhood trauma, if lives are to be saved, the main emphasis must be on prevention.

Accident Prevention↗
PubMed1985

Nonlinear natural engine: Model for thermodynamic processes in mesoscale systems.

To develop intuition on the possible application of concepts from thermodynamic heat engines to mesoscale systems, we have constructed and studied a model thermoacoustic heat engine. The model consists of a chain of coupled nonlinear acoustic vibrators in which the primary thermodynamic medium is argon gas, the secondary thermodynamic medium is constituted by solids bounding the gas, and frequencies are ca. 3 x 10(2) Hz. The nonlinear elements are the necks, made flexible by means of an oil-loaded DuPont Kapton film, of Helmholtz resonators. When the primary medium is driven uniformly by an acoustic driver at a frequency somewhat below the low-amplitude resonant frequency and at a high enough driving amplitude, stationary localized or solitary states appear irreversibly on the chain. These are characterized by a higher vibrational amplitude than that in surrounding vibrators, where the amplitude can decrease; by the appearance of deep subharmonics of the drive frequency, corresponding to driven low-frequency vibrations of the Kapton film-oil systems; and by the pumping of heat toward the localized states. Possible implications of these results for mesoscale systems consisting of chains of molecular vibrators are then discussed.

Journal Article↗
PubMed1975

Teaching self-examination of the head and neck: another aspect of preventive dentistry.

A technique for self-examination of the oral cavity and head and neck has been presented. The technique is simple in its design and yet thorough in its scope. The need for such an examination is established on the incidence of malignancies in this area and the importance of early detection, diagnosis, and treatment. The role of dental auxiliaries and the role of risk factors are discussed.

Face↗