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Biomedical subjects

M Gleeson

Publications and source records attributed to M Gleeson.

At least 91 records · Page 5Linked to original sources
PubMed1987

The development of IgA-specific antibodies to Escherichia coli O antigen in children.

One hundred and sixty-five infants were studied longitudinally from birth to 5 years of age. One hundred and twenty-three school-age children and 27 adults were examined cross-sectionally. Total salivary IgA levels and IgA antibodies against Escherichia coli O antigens were measured. Total IgA levels were low (less than 20 mg/l) from birth to 4 years of age. At 5 years of age there was a dramatic increase in the total IgA level (geometric mean = 100.7 mg/l), after which the levels fell to values similar to those observed in adults (adult geometric mean = 53.2 mg/l). Low levels of IgA-specific E. coli antibodies were observed for the first 4 years of life (less than 1.0 ELISA units). There was a gradual increase in specific antibodies between 5 and 9 years of age (geometric men at 9 years = 4.66 ELISA units) to levels similar to those observed in adults (adult geometric mean = 8.20 ELISA units). It is suggested that the patterns of development for these variables reflect a balance between antigenic exposure and immune control mechanisms.

Adolescent↗
PubMed1987

Ultrastructural findings on human Scarpa's ganglion.

The morphology of human Scarpa's ganglion from two surgically removed specimens as well as from four autopsy preparations from patients without clinical evidence of vestibular dysfunction was investigated. Ganglion cell circumference varied between 45 and 160 microns. More than half of the nerve cells ranged between 90 and 110 microns. The arrangement of ganglion cells, nerve fibres and endoneural connective tissue appeared better preserved in autopsy preparation than in biopsy specimens. Electron microscopy revealed that in half of the investigated specimens, neuroglial tissue was present as far distal as the vestibular ganglion. Almost all ganglion cells were surrounded by one or several layers of satellite cells, and did not reveal myelination. From the present study we cannot predict if neuronal function in human beings differs from that in other animals, although morphological differences do exist.

Adult↗
PubMed1987

A comparative study of the effect of age on the human cochlear and vestibular neuroepithelia.

A semi-quantitative and semi-qualitative comparative analysis was performed on the maculae and cochleas of 3 patients. The cochleas were examined by SEM and the maculae by TEM and light microscopy. The surface features of the cochleas were minimally affected by autolysis. Hearing loss and increasing age correlated well with inner and outer hair cell counts. In the labyrinth, the sacculi were more resistant to autolysis than were the utriculi and the type 2 cells better preserved than the type 1 cells. The pattern of cellular degeneration in the utriculus and sacculus varied with both age and functional deficit. Lipofuscin was present in the sensory cell of all 3 patients but was most pronounced in the oldest. Long-spaced collagen, laminated bodies and membrane-bound inclusions were seen in all maculae.

Aged↗
PubMed1987

Familial Prader-Willi syndrome.

Three adult sisters with previously unrecognized Prader-Willi syndrome (PWS) demonstrated the six diagnostic features of this congenital condition: neonatal hypotonia, hypomentia, hypogonadism, obesity, short stature, and dysmorphism. Detailed endocrine investigations were performed, including ovarian biopsy in the propositus. HLA genotype A2 was present in each patient. The normal high-resolution prometaphase karyotypes indicated heterogeneity; the absence of the deletion 15q12 frequently found in patients with sporadic PWS distinguished this sibship as representing a possible autosomal recessive type of PWS. Current evidence suggests that the diagnosis of PWS may be often overlooked. Increased clinical awareness of the features of PWS should result in prompt diagnosis and optimal management of affected patients, together with increased understanding of this enigmatic condition.

Adult↗
PubMed1986

A simple enzymatic fluorimetric method for the determination of triglycerides in 10 microliters of serum.

An assay for the determination of triglyceride (acyl glycerol) in microliter volumes of serum or plasma is described. The method is based on enzymatic hydrolysis of triglyceride by lipase from Rhizopus arrhizus followed by enzymatic fluorimetric assay of the glycerol so released. Under the conditions of the assay the enzymatic hydrolysis is complete for concentrations up to 5 mmol/l in less than 15 min at room temperature. The determination of free glycerol and glycerol released is based on the formation of dihydroxyacetone in the presence of NAD and glycerol dehydrogenase. The NADH which is formed in stoichiometric quantities is estimated fluorimetrically. In the presence of the ketone-trapping agent hydrazine the reaction goes to completion above pH 9.0. By this method acyl glycerol can be measured routinely in a 10 microliters sample of serum or plasma. The test is extremely sensitive compared to previously described methods and exhibits acceptable precision and reproducibility.

Fluorometry↗
PubMed1986

Comparison of the effects of pre-exercise feeding of glucose, glycerol and placebo on endurance and fuel homeostasis in man.

Six men were studied during exercise to exhaustion on a cycle ergometer at 73% of VO2max following ingestion of glycerol, glucose or placebo. Five of the subjects exercised for longer on the glucose trial compared to the placebo trial (p less than 0.1; 108.8 vs 95.9 min). Exercise time to exhaustion on the glucose trial was longer (p less than 0.01) than on the glycerol trial (86.0 min). No difference in performance was found between the glycerol and placebo trials. The ingestion of glucose (lg X kg-1 body weight) 45 min before exercise produced a 50% rise in blood glucose and a 3-fold rise in plasma insulin at zero min of exercise. Total carbohydrate oxidation was increased by 26% compared to placebo and none of the subjects exhibited a fall in blood glucose below 4 mmol X 1-1 during the exercise. The ingestion of glycerol (lg X kg-1 body weight) 45 min before exercise produced a 340-fold increase in blood glycerol concentration at zero min of exercise, but did not affect resting blood glucose or plasma insulin levels; blood glucose levels were up to 14% higher (p less than 0.05) in the later stages of exercise and at exhaustion compared to the placebo or glucose trials. Both glycerol and glucose feedings lowered the magnitude of the rise in plasma FFA during exercise compared to placebo. Levels of blood lactate and alanine during exercise were not different on the 3 dietary treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Cardiorespiratory responses to shivering in vagotomized pigeons during normoxia and hypoxia.

We measured respiratory, cardiovascular and blood gas responses to shivering during normoxia and hypoxia in five bilaterally, cervically vagotomized pigeons and compared these data with those previously reported in pigeons with intact vagi (Gleeson et al. 1986). Such neural section in birds denervates, among other receptors, the carotid bodies and intrapulmonary chemoreceptors. Normoxic breathing frequency (fR) and ventilation (VE) were decreased after vagotomy. Intact pigeons showed increases in oxygen consumption (VO2), tidal volume (VT), fR and VE during shivering. Vagotomized pigeons showed similar though slightly smaller increases in fR, VO2 and VE during shivering, but VT did not change. Normoxic heart rate was greater after vagotomy and was increased during shivering as in intact pigeons. Mean arterial blood pressure (MBPa) and stroke volume were not affected by vagotomy or shivering. At the onset of shivering both intact and vagotomized pigeons exhibited immediate increases in ventilation and heart rate. Exposure of vagotomized pigeons to hypoxic gas (fractional inspired oxygen concentration, FIO2 = 0.12) during cooling completely abolished shivering electromyogram (EMG) activity. In contrast, shivering in intact pigeons was not completely inhibited until the FIO2 fell below 0.10. We conclude that bilateral, cervical vagotomy in the pigeon causes hypoventilation and tachycardia during normoxia, but that these denervated birds are still able to rapidly effect cardiorespiratory adjustments to shivering. It is suggested that these responses are mediated mainly via afferent feedback from the shivering muscles. Hypoxia inhibits shivering in both intact and vagotomized birds and the mechanism is probably related to the reduced O2 delivery to the central structures that integrate thermoregulatory demand and coordinate appropriate responses.

Animals↗
PubMed1986

The effects of hypoxia on the metabolic and cardiorespiratory responses to shivering produced by external and central cooling in the pigeon.

Respiratory, cardiovascular and blood gas responses of pigeons to spinal cord cooling (36 +/- 1 degrees C), to ambient cooling (Ta = 5 degrees C) and to simultaneous spinal cord and ambient cooling were measured at three different levels of fractional inspired oxygen concentration (FIO2 = 0.209, 0.10 and 0.07). Shivering and the 'extra' VO2 provoked by ambient and/or spinal cord cooling were more or less reduced during hypoxic exposure depending on the intensity of cold stress and hypoxic states. At FIO2 = 0.10 shivering was markedly reduced and sometimes inhibited, whereas at FIO2 = 0.07 any pattern of cold tremor was inhibited. The accompanying cardiorespiratory responses were similar to those of thermoneutral controls exposed to the same FIO2. The amount by which VO2 was reduced in the pigeons exposed to hypoxia during ambient and/or spinal cord cooling was correlated, at both levels of hypoxia, to the thermoregulatory VO2 (viz. the 'extra' VO2 produced by cooling) prior to exposure to the hypoxic gas. The effect of hypoxia on shivering and associated cardiorespiratory adjustments was rapid and was completely reversible on return to air. We conclude that the thermoregulatory system in pigeons is sensitive to hypoxia, as is the case for mammals. The FIO2 that begins to inhibit thermoregulatory and metabolic responses to cold is lower in birds, perhaps as a result of the better ability of the bird to increase intrapulmonary gas and blood O2 convective transports when exposed to hypoxic gas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effect of bilateral vagotomy on arterial acid-base stability during panting in the pigeon.

Bilateral, cervical vagotomy denervates, among other receptors, the known peripheral chemoreceptors in birds. To test the importance of afferent vagal input to cardiorespiratory control during thermal panting, we measured responses to an increase in body temperature (Tb) induced by ambient heating in 6 bilaterally, cervically vagotomized pigeons. These responses were compared with those we previously reported in intact pigeons (control animals). At thermoneutral conditions, respiratory frequency (fR) was lower after vagotomy compared to controls, and PaCO2 was higher. During increases in Tb in both control and vagotomized pigeons, fR, PaO2, pHa, heart rate and oxygen consumption increased, and PaCO2 decreased. However, fR rose less, PaCO2 decreased more, and pHa increased more in the vagotomized pigeons than in controls. All three were more variable than in controls. Heart rate and blood pressure were higher than controls; blood pressure was more variable. We conclude that bilateral, cervical vagotomy compromises the ability of pigeons to maintain stable respiratory and cardiovascular responses to hyperthermia.

Acid-Base Equilibrium↗
PubMed1986

Influence of diet on the storage, mobilization and utilization of energy reserves in trained and untrained rats.

The effect of the major dietary energy source (fat or carbohydrate) on some of the adaptations to physical training, particularly body composition and tissue glycogen concentrations, were studied in growing male Wistar rats. Resting liver glycogen concentrations were lower in both trained and sedentary rats fed a high fat diet compared to corresponding rats fed a high carbohydrate (low fat) diet. Trained rats on both diets had higher liver glycogen levels than corresponding sedentary controls. Resting gastrocnemius muscle glycogen concentrations were not influenced by diet or training. Rates of liver and muscle glycogen depletion during a 60-min swim were lower in trained rats but were not influenced by diet. Significant interactions were noted between the dietary energy source and exercise training with respect to body weight gain, body fat content, liver weight and liver glycogen concentrations.

Animals↗
PubMed1986

Respiratory adjustments of the unanaesthetized chicken, Gallus domesticus, to elevated metabolism elicited by 2,4-dinitrophenol or cold exposure.

The effects of pharmacologically elevated metabolism on ventilation, gaseous exchange and blood gases were studied in spontaneously breathing unanaesthetized decerebrate chickens using 2,4-dinitrophenol (DNP) injected intravenously in successive single doses of 2.5-5.0 mg/kg. These responses were compared with the cardiorespiratory adjustments to elevated metabolism evoked by shivering in conscious birds. Oxygen consumption increased with cumulative amounts of DNP, reaching 275 +/- 30% of control values at the maximum tolerated dose of 10-15 mg/kg. Increases in ventilation matched the changes in oxygen consumption via increases in both breathing frequency and tidal volume. Arterial blood gases and pH remained unchanged. Exposure to cold (Ta = 2 +/- 2 degrees C) caused oxygen consumption to increase to 185 +/- 21% of control values. Respiratory and cardiovascular adjustments were similar to those evoked by DNP and were comparable to those produced by low intensity treadmill exercise (cf. Gleeson and Brackenbury, 1984).

2,4-Dinitrophenol↗
PubMed1986

Exercise hyperpnea in birds: evidence against a primary role for pCO2.

Ventilatory responses of domestic fowl to graded intensities of treadmill exercise were compared when the birds breathed air, 3% CO2 in air or 4.2% CO2 in air. During exercise in air, increased minute ventilation resulted mainly from increased respiratory rate with little change in tidal volume. This pattern of ventilatory response was not altered when the birds respired CO2. In contrast, the pattern of ventilatory response to CO2, at given work loads, consisted of a primary increase in tidal volume with little change in respiratory rate. It is concluded that intrapulmonary pCO2 does not affect the ventilatory response to exercise.

Animals↗
PubMed1986

Blood glucose monitoring by children at home: a comparison of methods.

The accuracy of measurements of blood glucose performed at home by the index children and/or parents was compared using the Boehringer Mannheim reagent strips, Ames Visidex-2 strips, an Ames Glucometer and a Boehringer Mannheim Reflolux reflectance meter. Capillary plasma samples, collected simultaneously, were later analysed by a Beckman glucose oxidase analyser. The coefficient of correlation between the self-monitored results (SMR) and the laboratory-analysed results (LAR) ranged from 0.59 to 0.92, the composite being 0.74. The mean difference between the SMR and the LAR was 1.0 mmol/l. The occurrence of potential errors of management due to incorrect SMR results was determined. On four occasions, the SMR was greater than 6 mmol/l when the LAR was less than 3 mmol/l, and on 36 occasions a discrepancy greater than 50% occurred between the two values, without resulting hypoglycaemia.

Adolescent↗
PubMed1986

Cardiorespiratory responses to hypoxia in intact and bilaterally vagotomized pigeons.

Bilateral, cervical vagotomy in birds denervates, among other receptors, the carotid bodies. To test whether such neural section removes sensitivity to hypoxia, we measured respiratory, cardiovascular, and blood gas responses to hypoxia at 84-, 70-, and 49-Torr inspiratory O2 partial pressure (PIO2) in five pigeons with intact vagi and in five bilaterally, cervically vagotomized pigeons. Normoxic respiratory frequency (fresp) and expiratory flow rate (VE) were decreased after vagotomy. Intact pigeons showed large increases in VE in response to hypoxia, effected mostly by increases in fresp. VE also increased greatly in response to hypoxia in vagotomized pigeons, but increases were largely the result of tidal volume. O2 consumption, CO2 production, and respiratory exchange ratio increased slightly in all pigeons during hypoxia. Normoxic heart rate was greater after vagotomy; cardiac output increased in all pigeons in response to hypoxia, but stroke volume increased only in intact pigeons. During normoxia, arterial and mixed venous O2 partial pressure, O2 concentration, and pH were lower and arterial and mixed venous CO2 partial pressure was higher, after vagotomy. In all pigeons during hypoxia, arterial and mixed venous O2 and CO2 partial pressure and O2 concentration decreased and arterial and mixed venous pH increased; changes were roughly parallel in intact and vagotomized pigeons. The arteriovenous O2 concentration differences during normoxia and hypoxia were similar in all pigeons. We conclude that bilateral, cervical vagotomy in the pigeon causes hypoventilation and tachycardia during normoxia, but strong respiratory and cardiovascular responses to hypoxia are still present.

Animals↗
PubMed1986

Respiratory responses of the domestic fowl to low level carbon dioxide exposure.

Respiratory function in the restrained, conscious domestic fowl was measured using a non-invasive technique and computer aided analysis to examine respiratory flow, and in-dwelling arterial catheters to monitor blood carbon dioxide levels. The effects of two low ranges of inspiratory carbon dioxide (0.2 to 1.0 per cent and 0.25 to 2.25 per cent) were studied, simulating levels of carbon dioxide that may occur in commercial poultry units and representing a mild environmental stress for the birds. A linear increase in minute volume with inspiratory carbon dioxide was observed, due primarily to increases in tidal volume. Arterial carbon dioxide (PaCO2) tension also rose as the inspiratory carbon dioxide concentration was raised, but higher inspiratory carbon dioxide levels were required to affect significantly blood carbon dioxide concentration than to modify respiratory parameters. Variation was observed in the individual bird's response to carbon dioxide (bird X carbon dioxide interaction), suggesting that resting values of the respiratory parameters measured were important in determining the bird's ventilatory response to carbon dioxide.

Analysis of Variance↗
PubMed1986

Variability in respiratory function of the domestic fowl.

Several respiratory parameters were measured in five groups of hens to estimate the variation in respiratory function of the general hen population. A non-invasive technique was used to measure respiratory flow, with computer-aided analysis of the data, and the results were examined statistically. Using different groups of hens, additional information was obtained regarding possible sources of variation between individual hens, such as egg laying condition, age and health. Significant differences between individuals within the groups were observed, but there were also changes in breath-to-breath variation for individual hens. While some changes in the variation between birds were observed from one group to another, variation within individual birds made interpretation of the results difficult. Repeated measurements made on one group revealed significant changes in minute volume with time, but the changes were not related to learning. Significant interactions between hens and time of measurement occurred for certain parameters, showing that the individuals' responses changed with time in different ways. The groups of hens were compared to observe whether they represented the same or distinct populations, and were found to overlap to varying extents for different respiratory parameters. Single respiratory variables and weighted combinations of certain variables were also used to separate the groupings, as a possible diagnostic method for partitioning groups of hens.

Animals↗
PubMed1986

Breast feeding conditions a differential developmental pattern of mucosal immunity.

A prospective study of 146 children was conducted to evaluate the influence of infant feeding patterns on the development of mucosal immunity. First, there was a trend towards lower IgG concentrations in the breast-fed neonate, indicating a possible earlier 'closure' mechanism of membrane permeability. Second, the post-natal increase in IgA was earlier and greater in formula-fed infants. Third, IgM was detected earlier, more frequently, and at higher levels in formula-fed infants.

Aging↗