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Biomedical subjects

W J Morgan

Publications and source records attributed to W J Morgan.

At least 37 records · Page 2Linked to original sources
PubMed1997

Vocalization and breathing during the second and third years of life.

Vocalization and breathing were studied in 40 healthy young children, including 5 boys and 5 girls at each, of ages of 18, 24, 30, and 36 months. A variable inductance plethysmograph was used to obtain estimates of volume changes of the rib cage, abdomen, and lung, as well as estimates of selected temporal features of the breathing cycle. Results indicated that breathing behavior was influenced by height and age, but not by vocalization type or sex. Such behavior was found to be highly variable, demonstrating that these young children had multiple degrees of freedom of performance available to accomplish the aeromechanical drive required.

Abdomen↗
PubMed1997

Role of magnetic resonance imaging in assessing factors affecting healing in scaphoid nonunions.

This study evaluates the role of magnetic resonance imaging in assessing the factors affecting the rate and healing time in scaphoid nonunions after surgery. Nineteen patients were assessed before surgery by radiographs, tomography, and magnetic resonance imaging. Fifteen had viable bone marrow and 4 patients had nonviable bone marrow on magnetic resonance imaging. All patients with normal preoperative magnetic resonance imaging healed in an average time of 4.7 months. Of the 4 patients with abnormal magnetic resonance imaging, but normal plain radiographs, 2 went on to heal in 10.5 months. The remaining 2 patients with abnormal magnetic resonance imaging and abnormal plain radiographs did not heal by 24 months. This study suggests 3 groups of scaphoid nonunions. Group 1 has normal trabecular bone radiographically and vascular bone marrow on magnetic resonance imaging and should be expected to heal after surgery. Group 2 has normal trabecular bone radiographically but avascular marrow on magnetic resonance imaging and may be expected to eventually heal after surgery. Group 3 has abnormal radiographs suggestive of fibrous replacement of the scaphoid proximal pole by the presence of cystic changes and the loss of trabecular bone, and avascular bone, as shown on magnetic resonance imaging. This study failed to show healing in this group of patients. Magnetic resonance imaging may be of benefit in predicting the healing potential in patients presenting with scaphoid nonunion.

Adolescent↗
PubMed1997

Peak flow variability, methacholine responsiveness and atopy as markers for detecting different wheezing phenotypes in childhood.

BACKGROUND: There is increasing evidence that wheezing during childhood may be a heterogeneous condition, and that different forms of wheezing may be associated with different risk factors and prognosis. The aim of this study was to determine if measures of airway lability and of atopy could identify distinct wheezing phenotypes during childhood. METHOD: In a cohort of children followed from birth peak flow variability (n = 600) was evaluated and methacholine challenge responsiveness (n = 397) was measured at age 11 in relation to wheezing before the age of three, and at age six and 11 years total serum IgE and skin test reactivity to allergens were determined. RESULTS: Neither positive peak flow variability nor methacholine hyperresponsiveness measured at age 11 were associated with wheezing occurring only during the first three years of life. Both methacholine hyperresponsiveness and positive peak flow variability were associated with wheezing at both ages six and 11 (OR 5.1 (95% CI 2.4 to 10.6) and 2.3 (1.2 to 4.5), respectively). In addition, positive peak flow variability was associated with wheezing up to the age of six but not at age 11 in non-atopic children (OR 2.9 (95% CI 1.0 to 8.8)). Methacholine hyperresponsiveness measured at age 11 was more frequently observed in boys (OR 2.1 (95% CI 1.2 to 3.5)) and was strongly associated with serum IgE levels measured at ages six and 11 (p < 0.001) and with positive skin test reactivity (OR 4.5 (95% CI 2.0 to 10.1)). Peak flow variability was unrelated to sex or markers of atopy (IgE and skin test reactivity). CONCLUSIONS: Methacholine responsiveness and peak flow variability assessed at age 11, together with markers of atopy (IgE and skin test reactivity to allergens) identify three different wheezing phenotypes in childhood: "transient early wheezing" limited to the first three years of life and unrelated to increased airway lability; "non-atopic wheezing" of the toddler and early school years associated with positive peak flow variability but not with methacholine hyperresponsiveness; and "IgE-associated wheeze/asthma" associated with persistent wheezing at any age and with methacholine hyperresponsiveness, peak flow variability, and markers of atopy.

Adolescent↗
PubMed1997

Cold air challenge at age 6 and subsequent incidence of asthma. A longitudinal study.

The aim of this study was to assess the relation between bronchial hyperresponsiveness to dry, cold air at age 6 and the subsequent incidence of asthma. The cumulative incidence of newly diagnosed asthma between ages 6 and 11 among 360 children included in this study was 12.0%. Survival analysis showed that hyperresponsiveness to cold air at age 6 was associated with an increased risk of developing subsequent asthma (hazard ratio = 2.6, 95% CI = 1.2-5.4; p = 0.01). However, after adjusting for potential confounders, only mild wheezing at age 6 (adjusted hazard ratio 7.5, 95% CI = 3.6-15.9; p < 0.001) and skin test reactivity to allergens at age 6 (adjusted hazard ratio 3.6, 95% CI = 1.5-8.5; p < 0.01), but not hyperresponsiveness to cold air (adjusted hazard ratio = 0.9, 95% CI = 0.4-2.2; p = 0.8), remained significant predictors of subsequent development of asthma. These findings were substantially confirmed after stratifying for wheezing illnesses before age 3. We conclude that hyperresponsiveness to cold air at age 6 was associated with subsequent development of a diagnosis of asthma but this effect was not independent of atopy and mild wheezing at age 6.

Age Factors↗
PubMed1996

The relation between physician-diagnosed sinusitis, asthma, and skin test reactivity to allergens in 8-year-old children.

The purpose of this study was to assess the prevalence of sinusitis in a nonselected sample of children, and the relation of sinusitis to allergic rhinitis (AR), atopy, asthma, and cough in the same population sample. Of 1246 children enrolled at birth in the Tucson Children's Respiratory Study, 835 were studied at a mean age +/-SD of 8.6 +/- 0.7 years. Questionnaires asking about MD-Sinusitis, MD-AR, MD-Asthma, and cough were completed by parents. Skin tests for seven common aeroallergens in the Tucson area had been performed in 630 of the participating children at the mean age +/-SD of 6.3 +/- 0.9 years. Prevalence of MD-Sinusitis was 13.1%; 78% of subjects with MD-Sinusitis also had MD-AR. Detailed analysis of the relation between MD-Sinusitis and individual environmental allergens tested for showed that only a response to Bermuda grass pollen was significantly associated with MD-Sinusitis after controlling for MD-AR [adjusted odds ratio 2.3 (95% CI 1.2-4.3)]. Having MD-Sinusitis was also significantly associated with MD-Asthma and cough [odds ratios 3.0 (95% CI 1.8-5.2)] and 2.5 (95% CI 1.6-3.8), respectively]. However, logistic regression demonstrated that, after controlling for MD-AR and skin test reactivity, MD-Sinusitis was no longer significantly associated with MD-Asthma or cough. We conclude that MD-Sinusitis is a common condition in childhood. The main independent risk factors in our community for MD-Sinusitis were grass pollen and current MD-AR. MD-Sinusitis was not associated with MD-Asthma or with cough after controlling for skin test reactivity and for MD-AR.

Allergens↗
PubMed1996

Vocalization and breathing during the first year of life.

Vocalization and breathing were studied in 40 healthy infants, including five boys and five girls each at ages 5 weeks, 2.5 months, 6.5 months, and 12 months. Breathing was monitored through the use of a variable inductance plethysmograph that enabled estimates of the volume changes of the rib cage, abdomen, and lung, as well as estimates of selected temporal features of the breathing cycle. Four vocalization types were studied intensively. These included cries, whimpers, grunts, and syllable utterances. Breathing behavior was highly variable across the four vocalization types, demonstrating the degrees of freedom of performance available to the infant to accomplish the aeromechanical drive required. Such behavior was influenced by body length, body position, and age, but not by vocalization type and sex. The protocol established is a useful tool for observing the natural course of the emergence of vocalization and breathing during the first year of life.

Age Factors↗
PubMed1996

Recurrent cough in childhood and its relation to asthma.

Risk factors for recurrent cough (RC) in childhood, and its relation to asthma were investigated as part of the prospective, longitudinal Tucson Children's Respiratory Study. RC, defined as > or = 2 episodes of cough without a cold in the past year, was assessed by questionnaire in 987 children at age 6. Children having RC without wheeze (n = 154) did not differ from children with neither symptom (n = 610) in serum IgE levels, skin test response, size-corrected forced expiratory flow, or percentage of decline following cold air challenge. In contrast, children with both RC and wheeze (n = 116) had significantly more respiratory illness, more atopy, lower flow at end-tidal expiration (V'maxFRC), and greater declines in lung function following cold air challenge than children with neither symptom. Current parental smoking was a risk for RC without wheeze, whereas male gender, maternal allergy, wheezing lower respiratory tract illness (LRI) in early life, and high IgE were significant risks for RC with wheeze, compared with children having neither symptom. RC early in life resolved in the majority of children, between ages 2-3 yr and age 6, and between age 6 and age 11. High IgE and positive skin prick test were associated with persistence of RC to age 6 among children who wheezed, and markers of allergy were associated with persistence of RC between 6 and 11 yr. These findings suggest that recurrent cough in the absence of wheeze differs in important respects from classic asthma, and using the same label to refer to these distinct syndromes may obscure their diverse pathophysiologies.

Asthma↗
PubMed1996

Segregation analysis of physician-diagnosed asthma in Hispanic and non-Hispanic white families. A recessive component?

The inheritance of asthma, evident from its high family concordance, is not well understood. To investigate whether asthma may be inherited through a major gene with two alleles, segregation analyses were conducted in 3,369 individuals from 906 nuclear families enrolled, without selection, in a longitudinal study of respiratory health in Tucson, Arizona. Physician-diagnosed asthma and its age of onset were ascertained for each family member when children were at a mean age of 7 yr. Age of asthma diagnosis was allowed for in analyses, and the impact of the covariate total serum IgE level on age of onset was examined. Segregation analyses were conducted with and without residual family effects, with and without the covariate IgE. The hypothesis of a single two-allele locus for asthma was rejected. However, depending on the method of assessment of the residual familial effects, either a polygenic/multifactorial mode of inheritance alone, or an oligogenic model with some evidence of a recessive component present in the population with the high frequency of 0.67, were compatible with the data. Results were unchanged with the addition of the covariate IgE.

Adult↗
PubMed1995

Asthma and wheezing in the first six years of life. The Group Health Medical Associates.

BACKGROUND: Many young children wheeze during viral respiratory infections, but the pathogenesis of these episodes and their relation to the development of asthma later in life are not well understood. METHODS: In a prospective study, we investigated the factors affecting wheezing before the age of three years and their relation to wheezing at six years of age. Of 1246 newborns in the Tucson, Arizona, area enrolled between May 1980 and October 1984, follow-up data at both three and six years of age was available for 826. For these children, assessments in infancy included measurement of cord-serum IgE levels (measured in 750 children), pulmonary-function testing before any lower respiratory illness had occurred (125), measurement of serum IgE levels at nine months of age (672), and questionnaires completed by the children's parents when the children were one year old (800). Assessments at six years of age included measurement of serum IgE levels (in 460), pulmonary-function testing (526), and skin allergy testing (629). RESULTS: At the age of six years, 425 children (51.5 percent) had never wheezed, 164 (19.9 percent) had had at least one lower respiratory illness with wheezing during the first three years of life but had no wheezing at six years of age, 124 (15.0 percent) had no wheezing before the age of three years but had wheezing at the age of six years, and 113 (13.7 percent) had wheezing both before three years of age and at six years of age. The children who had wheezing before three years of age but not at the age of six had diminished airway function (length-adjusted maximal expiratory flow at functional residual capacity [Vmax FRC]) both before the age of one year and at the age of six years, were more likely than the other children to have mothers who smoked but not mothers with asthma, and did not have elevated serum IgE levels or skin-test reactivity. Children who started wheezing in early life and continued to wheeze at the age of six were more likely than the children who never wheezed to have mothers with a history of asthma (P < 0.001), to have elevated serum IgE levels (P < 0.01), to have normal lung function in the first year of life, and to have elevated serum IgE levels (P < 0.001) and diminished values for VmaxFRC (P < 0.01) at six years of age. CONCLUSIONS: The majority of infants with wheezing have transient conditions associated with diminished airway function at birth and do not have increased risks of asthma or allergies later in life. In a substantial minority of infants, however, wheezing episodes are probably related to a predisposition to asthma.

Algorithms↗
PubMed1995

Bone mineral density changes in the forearm after immobilization.

This study determined the early natural history of disuse osteoporosis in the ulna and radius. Six women and 2 men (mean age, 48.5 years; range, 35-60 years) having surgery on their wrists or hands had bone mineral density determined by single energy xray absorptiometry at 4 sites of the distal radius and ulna before operation, at cast removal (mean, 4.9 weeks after surgery), and after an average of 4.7 weeks of remobilization and hand therapy. A control group of 4 men and 4 women (mean age, 35.6 years; range, 24-46 years) had bone mineral density measurements of both forearms taken initially and again 5 weeks later. The patients had significant loss in bone mineral density at the ulna and distal sites of the forearm after 4.9 weeks of immobilization. Loss of bone mineral density continued at all 4 sites even after 4.7 weeks of remobilization and hand therapy. Bone mineral density increased significantly at the ultradistal radius of the contralateral forearm (which was not operated on) after 4.9 weeks, but this gain was no longer significant after 4.7 weeks of remobilization of the surgically treated forearm, suggesting that increased activity of the nonimmobilized forearm increased bone mineral density at certain sites. No changes in bone mineral density were seen in the control group. Immobilization of the forearm after hand or wrist surgery significantly decreases bone mass in the distal radius and ulna.

Adult↗
PubMed1994

Pulmonary function in infants and children.

The assessment of pulmonary function in infants and children with lung disease can add substantially to their diagnosis and management. This article is a practical review of techniques such as peak flow measurement and spirometry which can be performed in the home or office setting. More complex methods such as airway challenge and infant lung function testing techniques also are discussed.

Child↗
PubMed1994

Complex fractures of the forearm.

Fractures of the forearm are frequently complex in their presentation and are often associated with injuries to the ligament and bone, with soft tissue loss. The development of improved biomechanic and surgical techniques has helped overcome previous disappointment in the treatment of these fractures. This article reviews the management of the following complex forearm fractures: comminuted or segmental diaphyseal fractures; Galeazzi, Monteggia, Essex-Lopresti fracture dislocations; and open fractures with bone and soft tissue loss.

Bone Transplantation↗
PubMed1994

Evidence for Mendelian inheritance of serum IgE levels in Hispanic and non-Hispanic white families.

Considerable evidence is available suggesting a significant genetic component in the pathogenesis of asthma, but the mechanism of inheritance is not well understood. The main objective of this study was to assess if total serum IgE level, a known intermediate phenotype for asthma, is under the control of a major autosomal gene. We studied nuclear families participating in the Tucson Children's Respiratory Study in Tucson and originally selected because they belonged to a health maintenance organization. One hundred twenty-five Hispanic and 673 non-Hispanic White nuclear families were eligible; 50 Hispanic families (with 191 subjects) and 241 non-Hispanic White families (with 886 subjects) were included. Prevalence of asthma, hay fever, and parental smoking was similar among eligible families who were included and those who were not. Segregation analyses using regressive models for continuous traits showed that the best fit to the data was given by a model of Mendelian codominant inheritance of a major autosomal gene associated with higher serum IgE level. Log-likelihood for this model was not significantly different from that of the best-fitting ("unrestricted") model (P = .3) and was significantly better than log-likelihood for a dominant model (P < .0001) and a recessive model (P < .0001). An environmental model showed significant departure (P < .0001) from the unrestricted model. Tests for genetic heterogeneity showed no significant difference between the two ethnic groups. The data strongly suggest that total serum IgE levels are controlled by a major autosomal codominant gene.

Arizona↗
PubMed1993

Child day care, smoking by caregivers, and lower respiratory tract illness in the first 3 years of life. Group Health Medical Associates.

BACKGROUND: Day-care attendance has been associated with an increased risk of hospitalization for lower respiratory tract illnesses (LRIs). This study examines, in a health maintenance organization population of children, the associations between child day care and the occurrence of LRIs in the first 3 years of life. Smoking by caregivers and a possible protective effect of longer day-care enrollment in relation to LRIs are also addressed. METHODS: Information on day-care arrangements was elicited from 1006 parents of infants for five age intervals in the first 3 years of life: birth through 3 months, 4 to 6 months, 6 to 12 months, 1 to 2 years, and 2 to 3 years. Data on LRIs in the first 3 years of life were recorded by pediatricians at the time of the acute illnesses. RESULTS: After controlling for other risk factors, the presence of three or more unrelated children in the care setting was associated with significant risks of LRI of up to twofold or more from 4 months of age to 3 years. Type of care setting was not a significant risk factor during this time period. In the third year of life, the risk of wheezing LRI in the presence of a smoking caregiver was more than threefold for those in another residential home setting. No significant protective effect against LRIs in the third year of life associated with longer prior day-care enrollment was demonstrated. CONCLUSION: The presence of three or more unrelated children in the care setting and the presence of a smoking caregiver were significant independent risk factors for LRIs during the first 3 years of life. Prolonged day-care did not protect against LRIs in the third year of life.

Caregivers↗
PubMed1992

Maternal age as a risk factor for wheezing lower respiratory illnesses in the first year of life.

Postneonatal mortality due to respiratory illnesses is known to be inversely related to maternal age, but the possible role of young motherhood as a risk factor for respiratory morbidity in infants has not been thoroughly explored. The authors studied the incidence of lower respiratory tract illnesses during the first year of life, as ascertained by health plan pediatricians, in over 1,200 infants enrolled at birth between 1980 and 1984 in Tucson, Arizona. The incidence of wheezing lower respiratory tract illnesses increased significantly (p = 0.005) with decreasing maternal age, whereas the incidence of nonwheezing lower respiratory tract illness was independent of maternal age. A logistic regression was used to control for the effects of several known confounding factors. When compared with infants of mothers aged more than 30 years, adjusted odds ratios were 2.4 (95% confidence interval 1.8-3.1) for infants whose mothers were less than age 21 years (p < 0.0001), 1.8 (95% confidence interval 1.4-2.3) for infants whose mothers were aged 21-25 (p < 0.0001); and 1.4 (95% confidence interval 1.1-1.6) for infants whose mothers were aged 26-30 (p < 0.001). These results suggest that young motherhood is an important risk factor for wheezing lower respiratory tract illnesses during the first year of life. Both biological and social factors related to maternal age may explain these findings.

Adult↗
PubMed1992

Risk factors for developing wheezing and asthma in childhood.

Wheezing lower respiratory tract illness in infancy and asthma share the clinical findings of wheezing and respiratory distress. Although the link between wheezing lower respiratory tract illness in infancy and the subsequent development of asthma is a limited one, both conditions do share some common risk factors, including exposure to environmental tobacco smoke, difficult living conditions (low socioeconomic class, crowding, allergen exposure), and increased risk in males. The impact of baseline lung function on wheezing lower respiratory tract illness risk is substantial and may be independent of airway reactivity. In contrast, the development of chronic airway inflammation mediated by allergic sensitization plays a central role in the development of persistent asthma. Although the endogenous risks for these two outcomes may be fixed, it is clear that caregivers may help to reduce or eliminate the exogenous risks listed earlier by parental education and improvement of the living conditions of young children.

Asthma↗
PubMed1992

Relationship between serum and saliva theophylline levels in patients with cystic fibrosis.

Theophylline levels in stimulated and unstimulated mixed saliva were compared with total and free (unbound) serum theophylline levels in 11 outpatients with cystic fibrosis (CF) who were using theophylline regularly. Stimulated saliva from CF patients predicted both total and unbound serum theophylline concentrations to within +/- 1 microgram/ml in 53.3 and 80.0%, respectively, of the samples examined. In addition, the total serum levels from CF patients could be used to predict unbound serum concentrations to within +/- 1 micrograms/ml in 100% of the cases examined. Furthermore, it was observed that prediction equations derived in a previous study with asthmatics employing identical methodology would allow both unbound and total serum theophylline levels to be predicted from saliva levels in CF patients with a degree of accuracy and precision that was approximately equal to or slightly better than the results obtained using prediction equations derived in other CF patients. These results indicate that saliva levels allow predictions of the unbound serum theophylline levels with greater accuracy and precision than they predict total serum theophylline levels. In addition, total serum levels can be used to reliably predict unbound serum levels. The use of mixed stimulated saliva is recommended as a reliable noninvasive method for monitoring unbound serum theophylline levels. The therapeutic range for saliva, which corresponds to the accepted total serum concentration range of 10-20 micrograms/ml, is approximately 5.55-11.3 micrograms/ml.

Adolescent↗