Biomedical subjects

W J Morgan

Publications and source records attributed to W J Morgan.

At least 19 recordsLinked to original sources

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↗

PubMed1992

Variability of the serum protein binding of theophylline in patients with asthma and cystic fibrosis.

1. The serum protein binding of theophylline was studied in 28 asthmatics and 11 patients with cystic fibrosis (CF) who were receiving the drug regularly. Peak theophylline samples were collected at 2 week intervals on four occasions in each asthmatic and on three occasions in each CF patient. The binding was measured using ultrafiltration at 37 degrees C and pH 7.4. The total and free (unbound) theophylline concentrations were measured using high-performance liquid chromatography. 2. The mean free-fractions (+/- s.d.) in asthmatics (0.50 +/- 0.03) and in CF patients (0.51 +/- 0.04) were not significantly different. The intra- and inter-subject variability in the free-fraction (fu) was relatively small in both patient groups. The binding was found to be concentration-independent at serum theophylline concentrations up to 30.9 micrograms ml-1. The effects of age, gender, serum albumin and total serum protein on the free fraction were evaluated. 3. The results indicate that the binding of theophylline is similar in the two disease states. The low degree of variability in serum theophylline binding indicates that measurements of total serum theophylline concentrations will reflect unbound serum concentrations with acceptable accuracy in both patient groups studied.

Adolescent↗

PubMed1991

Serum/saliva correlations for theophylline in asthmatics.

Theophylline levels in mixed saliva (both stimulated and unstimulated) were compared with total and free (unbound) serum theophylline levels in 28 asthmatic outpatients using theophylline regularly. Stimulated saliva predicted both total and unbound serum theophylline concentrations within +/- 1 microgram/mL in 62.5% and 92.9%, respectively, of the samples examined. In addition, the total serum levels could be used to predict unbound serum concentrations to within +/- 1 mg/L in 100% of the cases that were examined. These results indicate that saliva levels predict 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 non-invasive method for monitoring unbound serum theophylline levels. The therapeutic range for saliva, which corresponds to the accepted total serum concentration range of 10-20 mg/L, is approximately 5.6-11.3 mg/L.

Administration, Oral↗

PubMed1991

Circulating levels of tumor necrosis factor and interleukin-1 in cystic fibrosis.

To assess the role of tumor necrosis factor (TNF) and interleukin-1 (IL-1) in the pathophysiology of cystic fibrosis (CF)-associated growth failure/cachexia and lung disease we measured height, weight, triceps skin fold, forced vital capacity, forced expiratory volume in 1 second, and plasma levels of TNF, interleukin-1-alpha (IL-1 alpha), interleukin-1-beta (IL-1 beta), and alpha-1-antitrypsin (A1AT) in 12 patients with CF, and in 12 age- and gender-matched healthy controls. The patients as a group had significantly lower values for the anthropomorphic measurements and lung function parameters as compared to controls. They also had higher circulating levels of A1AT than controls. TNF, however, was detected less frequently in patients than in controls. Neither group had detectable levels of circulating IL-1 alpha or IL-1 beta, which is consistent with the observation that CF patients infrequently present with fever. Potential explanations for these findings include compartmentalization of secreted TNF/IL-1, altered regulation of TNF/IL-1 secretion as a result of the chronic inflammatory state seen in CF, or increased degradation of TNF/IL-1, also a result of chronic inflammation. The role of these cytokines in the pathophysiology of CF remains unclear, but should be explored further; however it seems unlikely that circulating TNF plays a role in the growth failure/cachexia associated with CF.

Adolescent↗

PubMed1991

Technical considerations in pectoralis major transfer for treatment of the paralytic elbow.

Modification of pectoralis major transfer as originally described by Clark in 1946 have not addressed concerns such as diminished strength and excursion of the transfer, along with obligatory supination of the forearm. Postoperative scarring from the long oblique chest incision further compounds the psychological impairment that accompanies brachial plexopathy. One hundred forty-three brachial plexopathies were seen over a five-year period. Seven pectoralis major transfers were done to restore elbow flexion in patients with C5-6 and C5-6-7 cord injuries. Mean age and follow-up were 26 years and 25 months respectively. The modifications of this transfer we use improve strength and range of motion by preserving dual innervation of the muscle, by tubularization of the transfer, and by restoration of the transverse aponeurosis as a fascial pulley. By transfer of the pectoralis insertion to the acromion, further anterior shoulder stability may be obtained. Aesthetics can also be improved by use of selected midline and deltopectoral incisions, along with preservation of the remaining pectoralis major and minor.

Adult↗

PubMed1991

Locked thumb metacarpophalangeal joint caused by sesamoid entrapment.

We report an unusual case of locked thumb in a 24-year-old man, caused by entrapment of the radial sesamoid in the metacarpophalangeal joint. Tomography clearly revealed sesamoid entrapment in the joint. Surgical exploration and cadaver dissection demonstrated that avulsion of the proximal portion of the palmar plate and some dissociation of the sesamoid from the palmar plate with intraarticular displacement were necessary for the sesamoid to be trapped in the joint.

Adult↗

PubMed1991

Initial airway function is a risk factor for recurrent wheezing respiratory illnesses during the first three years of life. Group Health Medical Associates.

We recently reported a significant relationship between lung function measured prior to any lower respiratory tract illness and subsequent wheezing illnesses during the first year of life (N Engl J Med 1988; 319:1112-7). Follow-up has continued for this group of infants during the second and third years of life. When compared with never wheezers, infants who wheezed during the first year of life and had at least one additional lower respiratory illness had 22% lower initial levels of an indirect index of airway conductance derived from the shape of tidal breathing curves (p less than or equal to 0.01), 22% lower respiratory conductance (p less than or equal to 0.05), 25% lower maximal flows at the end-expiratory point (p less than or equal to 0.01), and 10% lower functional residual capacity (p less than or equal to 0.05). Infants who wheezed only once during the first 3 yr of life or who started wheezing during the second year of life had normal tidal breathing curves but significantly lower maximal expiratory flows (p less than or equal to 0.05). Their functional residual capacity was also lower than that of never wheezers (p less than or equal to 0.05). We conclude that diminished initial airway function may be a predisposing factor for recurrent wheezing respiratory illnesses starting in the first year of life. Infants who will have only one wheezing respiratory illness or who will start wheezing after the first year of life seem to have lower levels for some but not for all lung function tests performed in this study.

Age Factors↗

PubMed1990

Infants with upper respiratory illnesses have significant reductions in maximal expiratory flow.

We studied maximal expiratory flows at functional residual capacity (VmaxFRC) obtained by use of the chest compression technique in 9 infants who had signs of upper respiratory illness (URI) at the time of testing, and in 9 infants who were symptom-free but whose parents reported they had a URI in the previous month. When compared to 109 infants with no URI, infants with current URI had 40% lower VmaxFRC (mean +/- SD: 125.7 +/- 54.5 mL/s vs. 73.6 +/- 53.6 mL/s; P less than 0.01). Infants with a past URI had mean values for VmaxFRC (120.2 +/- 50.2 mL/s) that were not significantly different from those of infants with no URI. Changes in the shape of the flow-volume loop analogous to those reported in infants with lower airway obstruction were also noticed in infants with current URI. These findings suggest that, as in older children and adults, clinically unapparent alterations in lower airway function occur during URI in infants.

Analysis of Variance↗

PubMed1990

On the creation of 'problem' patients.

Recent debates regarding clinical transactions oppose a macro-level approach which emphasizes political, economic and institutional forces, and those analysts who consider patient perceptions regarding illness to be major influences on the outcome of clinical encounters. This paper utilizes both approaches to illuminate the interactions between medical personnel and 'problem patients'. The macro-level approach draws attention to the way power is negotiated and expressed in clinical interactions, and to medicalization that gives priority to medical values and condemns patients who do not act in accord with these values. The patient belief approach explores one of the major weapons in the struggle for control, the disease model of illness. Use of both approaches permits a better understanding of clinical medicine in these problematic interactions.

Adult↗

PubMed1990

Speech breathing in children and adolescents.

An investigation was conducted to elucidate the nature of speech breathing in children and adolescents and to determine if sex and age influence performance. Eighty healthy boys and girls representing four age groups (7, 10, 13, and 16 years) were studied using helium dilution to obtain measures of subdivisions of the lung volume and using magnetometers to obtain measures of resting tidal breathing and speech breathing. Results for subdivisions of the lung volume and resting tidal breathing revealed sex- and age-related differences, most of which were attributable to differences in breathing apparatus size. Results for speech breathing indicated that sex was not an important variable, but that age was critical in determining speech breathing performance. The most substantial differences were between the 7-year-old group and older groups. These differences were characterized by larger lung volume, rib cage volume, and abdominal volume initiations and terminations for breath groups, larger lung volume excursions per breath group, fewer numbers of syllables per breath group, and larger lung volume expenditures per syllable for the 7-year-old group compared to older groups. In most respects, speech breathing appeared adultlike by the end of the first decade of life. Clinical implications regarding these findings are offered.

Adolescent↗

PubMed1990

A rapid and specific high-performance liquid chromatographic assay for theophylline in biological fluids.

A rapid, specific high-performance liquid chromatographic analysis of theophylline in plasma, serum, and saliva is described. Proteins present in the biological samples are precipitated with 6% perchloric acid and the clear supernatant is chromatographed on a reversed-phase column. Only 100 microL of serum is required and concentrations as low as 0.07 micrograms/mL can be measured accurately. Other xanthines do not interfere in the assay. Within- and between-day variation is less than or equal to 2.2%. The method shows less bias and greater precision than the TDx (Abbott Diagnostics) procedure commonly used in clinical laboratories.

Chromatography, High Pressure Liquid↗

PubMed1989

Breast feeding and lower respiratory tract illness in the first year of life. Group Health Medical Associates.

OBJECTIVE: To assess the relation between breast feeding and subsequent experience of lower respiratory tract illness. DESIGN: Prospective (from well child visits) and retrospective (from maternal recall) study of breast feeding and prospective assessment by paediatricians of lower respiratory tract illness in infants during first year of life. SETTING: Health maintenance organisation. PARTICIPANTS: Over 1000 infants who were healthy at birth and whose parents used the paediatricians of a local health maintenance organisation. MAIN OUTCOME MEASURES: Duration of breast feeding and type of lower respiratory tract illness (wheezing and non-wheezing) at different age intervals during the first year of life. RESULTS: Breast feeding was associated with a decreased incidence of wheezing illnesses only in the first four months of life. Interactions existed between breast feeding and sharing a room, being Mexican American, and being a boy. Multivariate techniques showed that after controlling for a variety of factors children who received minimal breast milk had a greater risk of early wheezing illnesses; the risk was further increased by simultaneous exposure to sharing a room. CONCLUSION: Breast feeding seems to protect against wheezing respiratory tract illnesses in the first four months of life, particularly when other risk factors are present.

Breast Feeding↗

PubMed1989

Speech breathing in women.

Thirty healthy women representing three age groups (25, 50, and 75 years) were studied with respect to general respiratory function and speech breathing. Certain subdivisions of the lung volume differed with age: vital capacity, expiratory reserve volume, and residual volume. Speech breathing also differed with age and was characterized by differences in lung volume excursion, rib cage volume excursion, lung volume initiation, rib cage volume initiation, and lung volume expended per syllable. Age-related differences in general respiratory function and speech breathing are discussed in relation to possible underlying mechanisms. In addition, patterns of function observed in women are compared to those observed in men in an earlier investigation (Hoit & Hixon, 1987). Clinical implications are drawn regarding the evaluation and management of speech breathing disorders.

Adult↗

PubMed1989

The Tucson Children's Respiratory Study. I. Design and implementation of a prospective study of acute and chronic respiratory illness in children.

The Tucson Children's Respiratory Study, Tucson, Arizona, has been established as a long-term, longitudinal, prospective study of the risk factors for acute lower respiratory tract illnesses in early childhood and for chronic obstructive airways disease in later life. A total of 1,246 newborns were enrolled into the study between May 1980 and January 1984, representing 78% of eligible infants. Cord blood for immunologic studies, neonatal blood specimens for blood counts and differentials, and blood specimens at nine to 15 months of age for immunologic studies, blood counts, and differentials have been obtained on the majority of enrolled children. Pre-illness physiologic and more detailed immunologic studies have also been done on large subgroups of subjects. The majority of lower respiratory tract illnesses suffered by these children in the first three years of life have been assessed in detail for etiologic agents by means of culture and serologic techniques; 1,052 illnesses have been evaluated thus far. The type of illness and nature of etiologic agents are very similar to those reported in other epidemiologic studies. Thus, this group of enrolled infants and their family members constitute an appropriate population for the long-term study of risk factors for acute and chronic respiratory disorders.

Acute Disease↗

PubMed1989

Repair of the isolated cut flexor digitorum profundus tendon under intravenous regional anaesthesia.

Intravenous regional anaesthesia proved to be an effective anaesthetic agent for the repair of isolated cut flexor digitorum profundus tendons. Twenty-five patients underwent primary repair, of whom 20 were assessed 1 year later. Overall results were satisfactory regarding movement at the distal joint. Five of the cases were missed at initial examination and the repair carried out longer than 1 week from the injury. In view of the generally accepted poor initial diagnosis in the Emergency Department for the isolated flexor tendon lesion, exploration under a simply performed local anaesthetic block has advantages where the diagnosis is in doubt. The main operative problem with this technique was the venous ooze which occurred during the operation, and this could be a contraindication to its use for more complicated hand surgery.

Anesthesia, Conduction↗

PubMed1989

A mathematical procedure for estimating the spatial relationships between lung function, somatic growth, and maturation.

A mathematical procedure is described for examining growth velocity rates of lung function (FEV1) in relationship to somatic growth and maturation. This procedure uses a polynomial smoothing spline model to yield a fitted curve through the data and to estimate the process first derivatives (i.e. growth velocity curves). We demonstrate this technique using data from children and adolescents enrolled in the Tucson Epidemiological Study of Airway Obstructive Diseases. The study group consisted of 772 healthy normal subjects, aged 3 to 25 y. The results for the normal subjects (male and female) indicate that the growth velocity peak (GVP) of somatic growth leads the GVP of functional growth (FEV1) by approximately 7 and 11 mo for females and male subjects, respectively, and that the GVP of maturation lags behind that of functional growth (FEV1) by approximately 1 y (male and female subjects). In addition, the normal subjects' growth velocity curves for FVC and FEV1/FVC were examined. The FEV1/FVC ratio was consistently high, and its growth velocity was not significantly different than 0 over the age range studied. This suggests that in normal children, the GVP seen in FEV1 is primarily due to a GVP in vital capacity or lung vol, rather than to a direct effect on expiratory flow rates alone. From this study we concluded that the polynomial smoothing spline procedure can adequately model the inherently noisy pulmonary function data and additionally yield an accurate estimate of the process first derivative.

Adolescent↗