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Biomedical subjects

A D Milner

Publications and source records attributed to A D Milner.

At least 145 records · Page 8Linked to original sources
PubMed1990

Estimation of lung volume in infants by echo planar imaging and total body plethysmography.

Echo planar imaging (an extremely fast method of magnetic resonance imaging) was used to measure lung volume in a group of nine infants, all of whom had had respiratory problems. The mean echo planar imaging estimate of total lung volume was 44 +/- 9 ml/kg. In each case the right lung was larger than the left (ratio 52.8:47.2%). The mean thoracic gas volume was 36 +/- 8 ml/kg. The entire sequence of images of the thorax (about 400) takes five minutes to complete, infants require no sedation, and there are no side effects.

Female↗
PubMed1990

Nebulised sodium cromoglycate in infancy: airway protection after deterioration.

Over a two year period 100 infants with histories of wheeze were challenged with nebulised water. They were sedated and lung function measured by total body plethysmography. Thirteen of the 53 infants who developed bronchoconstriction after challenge with nebulised water were given nebulised sodium cromoglycate and rechallenged with nebulised water. All infants were initially challenged with normal saline, after which there was no significant change in lung function. After challenge with nebulised water and sodium cromoglycate there were significant decreases in specific conductance compared with those found after challenge with normal saline. After rechallenge with nebulised water there was no deterioration in lung function. Although sodium cromoglycate caused a deterioration in lung function in these infants, it protected their airways from challenge with nebulised water.

Airway Resistance↗
PubMed1990

Adrenal function in asthma.

A dose dependent suppression of daily cortisol excretion was shown in 25 children with asthma being treated with beclomethasone dipropionate. Cortisol metabolites tended to occur below the normal range when doses of beclomethasone of more than 400 micrograms/m2/day were given. Androgen excretion below the normal range was apparent in asthmatic children aged 8-13 years regardless of whether they were receiving inhaled steroids. This may be the reason for growth delay often seen in asthmatic children. These side effects of beclomethasone are not enough reason to discourage its prescription for the treatment of asthma, but endocrine assessment is desirable when the dose exceeds 400 micrograms/m2/day.

Adolescent↗
PubMed1989

Inspiratory-to-expiratory ratio during ventilation for idiopathic respiratory distress syndrome.

We have studied the effects of changes in inspiratory-to-expiratory ratios (I/E ratios) on transcutaneous blood gases in a group of 30 infants receiving respiratory support for the idiopathic respiratory distress syndrome (IRDS). Following the use of a reversed I/E ratio (inspiration exceeding expiration), changes in oxygenation were very variable but improvements were seen most consistently in babies weighing greater than 1,750 g and less than 850 g. The use of reversed I/E ratios seemed less efficient than positive end-expiratory pressure in raising TcPO2 for the same increase in mean airway pressure. Changes from a 1:1 ratio to a normal I/E ratio, in which expiratory time exceeded inspiratory time by 50-100%, led to more marked and consistent falls in TcPO2. We conclude that a flexible attitude toward the use of I/E ratios should be adopted to avoid raising mean airway pressure needlessly.

Animals↗
PubMed1989

Do lung volumes change with sleep state in the neonate?

We have studied 12 healthy full-term babies, mean age 3.2 days, using physiological criteria--EEG, electrooculogram, electromyogram, respiratory regularity and visible movement--to assess sleep state, and a respiratory jacket to record changes in functional residual capacity (FRC). A total of 593 min of sleep data were analysed. Of the recordings, 39% were scored as quiet sleep, 40% as active and 21% as indeterminate sleep. The mean maximum variation in FRC overall was 29 ml (SD +/- 15.4 ml). Examination of these figures showed that FRC variations during sleep state changes were smaller than those seen within a defined sleep state. We conclude that changes in sleep state are not associated with variations in FRC.

Functional Residual Capacity↗
PubMed1989

Inaccurate calculation of drug output from nebulisers.

A multistage liquid impinger was used to collect the nebulised cloud from three separate nebulisers. The output of sodium cromoglycate collected was determined by a spectrophotometric assay. Estimating drug output purely from weight loss during nebulisation resulted in a considerable overestimate compared with direct assay of the drug output from the nebulised cloud. During nebulisation, weight loss from the nebuliser occurs in the form of particle formation and also by evaporation. By only weighing the nebuliser chamber before and after nebulisation, weight loss due to evaporation is not taken into account and this is the cause of the overestimation of drug output by this method.

Aerosols↗
PubMed1989

A disorder of lightness discrimination in a case of visual form agnosia.

Benson and Greenberg (1969) described an "agnosic" patient whose severe visual recognition disorder could be accounted for in terms of a deficit in the perception of shape. We report here on a recent case of this disorder (visual form agnosia), and have found that she performs very poorly on tasks of discriminating shades of grey, although she is able to discriminate between hues. This sensory deficit helps to explain some of her perceptual difficulties; it also provides further evidence for parallel feature-processing in the human brain complementary to and consistent with recent physiological data on the visual cortex in animals.

Adult↗
PubMed1989

CNV abnormalities following closed head injury.

Event-related potentials (ERPs) were recorded in a GO/NO-GO reaction time task from 20 closed head injury patients, at least 6 months postinjury, and from 20 controls. In this task the pitch of an initial tone (Sl) indicated whether or not a response was required to a second tone (S2) occurring 1.5 s later. In the control group both the early, frontal-maximum, and the later vertex-maximum, components of the contingent negative variation (CNV) were larger on GO than NO-GO trials. In the patients, the early frontal CNV wave did not differentiate GO and NO-GO trials, and the late CNV showed a smaller separation between these trial types than did the late CNV of the control group. These CNV abnormalities may reflect impairments in selectively orienting to salient stimuli, and in differential response preparation. Such impairments might in turn reflect the damage to the frontal lobes and/or their connections that commonly occurs as a result of closed head injury.

Acoustic Stimulation↗
PubMed1989

Interferon alfa, infectious virus, and virus antigen secretion in respiratory syncytial virus infections of graded severity.

Interferon alfa was measured by an immunoradiometric assay in the nasopharyngeal secretions of a group of infants admitted to hospital with respiratory syncytial virus infection. Virus replication in the upper respiratory tract was assessed by infectivity assay and by an enzyme linked immunoadsorbent assay for the viral fusion protein on the same nasopharyngeal secretions. All infants were examined daily while in hospital and allocated a score based upon a subjective assessment of the severity of their illness. There was no significant correlation between interferon, virus, or fusion (F) protein secretion and severity of illness or age of infant. It is concluded that poor interferon alfa secretion does not underly the susceptibility of infants to severe infections with this virus.

Antigens, Viral↗