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Biomedical subjects

H Levison

Publications and source records attributed to H Levison.

At least 73 records · Page 4Linked to original sources
PubMed1989

DNA marker haplotype association with pancreatic sufficiency in cystic fibrosis.

Patients with cystic fibrosis (CF) generally suffer from chronic obstructive lung disease, pancreatic insufficiency (PI), and a number of other exocrine malfunctions. Approximately 15% of CF patients are, however, pancreatic sufficient. To investigate whether the two clinical subgroups, PI and pancreatic sufficiency (PS), are caused by different CF mutant alleles, we have performed linkage disequilibrium and haplotype association analysis with three DNA markers that are tightly linked to the CF locus. The study showed that the allelic and haplotype distributions for these RFLPs are significantly different between the two groups. The data suggest that most of the CF-PI patients are probably descendants of a single mutational event at the CF locus and that the CF-PS patients resulted from multiple, different mutations. While final interpretation of these data awaits molecular cloning of the CF gene, the information on haplotype association in CF may be useful in genetic counseling and disease prognosis, in identifying the gene itself, and in defining the mutations.

Adolescent↗
PubMed1989

Severe acute asthma in a pediatric intensive care unit: six years' experience.

The management of children with severe acute asthma who required admission to the intensive care (ICU) of this hospital during 1982 to 1988 was reviewed retrospectively. A total of 89 children were admitted to the ICU on 125 occasions. During the study period, 24% of the patients were admitted to the ICU on more than one occasion. Prior to admission to this hospital, patients had been symptomatic for a mean of 48 hours. Although all patients had received bronchodilators before admission to hospital, only 23% of patients had received oral corticosteroids. According to initial arterial blood gas values determined in the ICU, 77% of the patients had hypercapnia (PaCO2 greater than 45 mm Hg). The pharmacologic agents used in the ICU included nebulized beta 2-agonists (100% of admissions), theophylline (99%), steroids (94%), nebulized ipratropium bromide (10%), IV albuterol (38%), and IV isoproterenol (10%). Mechanical ventilation was necessary in 33% of admissions; the mean duration of ventilation was 32 hours. Ten patients had pneumothorax; in six cases, these were related to mechanical ventilation. Three of the patients who received mechanical ventilation died, representing a mortality of 7.5%. In each of these patients, sudden, severe asthma episodes had developed at home, resulting in respiratory arrest. They had evidence of hypoxic encephalopathy at the time of admission to the ICU and eventually were declared brain dead. It was concluded that delay in seeking medical care and underuse of oral corticosteroids at home may have contributed to the need for ICU admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Acute asthma: observations regarding the management of a pediatric emergency room.

Because inadequate assessment and inappropriate treatment of acute asthma have been implicated as contributing factors in morbidity and even deaths, the management of acute asthma, as practiced in an emergency room, were reviewed. The study population comprised 1,864 children (mean age 5.6 years; 65% boys) who attended the emergency room with acute asthma on 3,358 occasions during a 16-month period. Visits occurred more commonly in winter and usually in the evenings; 93% were self-referred and the mean duration of symptoms was 41 hours. Most acute episodes were associated with infection. Although chest auscultation, heart rate, and respiratory rate were recorded during the majority of visits, evidence that pulsus paradoxus had been measured could be found for only 1% of visits. Results of lung function and blood gas values were rarely recorded, but chest radiographs were obtained in 18% of visits. Drugs used in the emergency room included beta 2-agonists (93% of visits), theophylline (16%), and systemic steroids (4%), but no child received anticholinergic therapy. In 26% of patient visits, admission to hospital occurred; one patient died. The erratic fashion in which asthma severity appears to have been assessed and the failure to document whether lung function had been measured are causes for concern. The surprisingly high hospitalization rate may have been avoided if bronchodilators and corticosteroids had not been underused in the emergency room.

Acute Disease↗
PubMed1989

High-versus low-dose, frequently administered, nebulized albuterol in children with severe, acute asthma.

Thirty-two 5- to 17-year-old children who had severe, acute asthma were randomly assigned to receive either high doses (0.15 mg/kg of body weight per dose) or low doses (0.05 mg/kg of body weight per dose) of nebulized albuterol every 20 minutes for six doses. Compared with the low-dose regimen, the high-dose regimen resulted in significantly greater improvement in forced expiratory volume in 1 second, forced vital capacity, and wheeze score and a lower hospitalization rate. The changes in heart rate, respiratory rate, blood pressure, white blood cell count, and serum potassium concentration did not differ significantly between the groups. The incidence of side effects, which included tremor, hyperactivity, and vomiting, was not significantly different in the two populations. Serum albuterol levels varied widely, but there was no correlation between the levels and the increase in heart rate or other side effects. high-dose, frequently administered, nebulized albuterol appears both safe and effective in treating severe, acute asthma in children.

Acute Disease↗
PubMed1988

Frequent administration by inhalation of salbutamol and ipratropium bromide in the initial management of severe acute asthma in children.

A study was performed to compare the efficacy and safety of two therapeutic regimens for the treatment of children presenting to the emergency department with acute asthma. A regimen of inhaled salbutamol alone was compared to inhaled salbutamol combined with ipratropium bromide. Twenty-five children ranging in age from 5 to 15 years were enrolled in the study. Children with FEV1 less than or equal to 55% predicted were eligible to participate in the study. Subjects were randomized in a double-blind fashion into one of two treatment groups. Both groups received an initial dose of salbutamol by nebulizer of 150 micrograms/kg (0.03 cc/kg), followed by six consecutive doses of 50 micrograms/kg (0.01 cc/kg) at 20-minute intervals. In one group of subjects, 250 micrograms (1.0 ml) of ipratropium bromide respirator solution was added to the salbutamol administered at the time of the initial inhalation, and at 40 and 80 minutes, whereas the remaining subjects received a placebo with salbutamol at those times. Formal one-way statistical ANOVA with change in percent predicted FEV1 as a response variable confirmed there was a statistically significant difference at all time points caused by drug regimen during the 150-minute observation period. There was no significant difference in side effects reported in the two groups. Significant additional bronchodilation achieved with salbutamol and ipratropium bromide together indicates that there is likely a substantial cholinergic element to the bronchospasm observed in acute exacerbations of asthma in the pediatric age group.

Administration, Inhalation↗
PubMed1988

Allergy in asthma. I. The dose relationship of allergy to severity of childhood asthma.

The relationship between allergy and childhood asthma was investigated. We hypothesized that if allergy were a factor in aggravating asthma, we should find that allergy (defined by symptoms and numbers of positive prick skin tests) increased with increasing severity of asthma. One hundred forty-two children with asthma, referred to a pulmonologist and an allergist, 123 of whom were skin tested, were graded according to clinical severity and compared to a group of 29 normal individuals, 48 patients with allergic rhinitis, and 52 patients with cystic fibrosis. The 29 symptom-free individuals had only one positive skin test among them, whereas 65% of the clinic patients with asthma had three or more positive skin tests (p less than 0.001). This compared with 35.4% of the patients with rhinitis (p less than 0.001) and 14% of the patients with cystic fibrosis (p less than 0.001). There was an increase in the number and size of positive skin tests with increasing severity of asthma. Similarly, there was increased reporting of allergic symptoms, such as sensitivity to animals with increasing severity of asthma. These data indicate that atopy is associated with asthma in a crude dose-response fashion, and children with chronic, steroid-dependent asthma are often highly atopic, easily sensitized, and form IgE antibodies to a broad range of allergens.

Adolescent↗
PubMed1988

A comparison of survival, growth, and pulmonary function in patients with cystic fibrosis in Boston and Toronto.

Two cystic fibrosis (CF) clinic populations of similar size and age distribution were compared with respect to growth, pulmonary function, and survival. Height and weight measurements were made on 499 patients in Boston (mean +/- SD age 15.9 +/- 9.6, range 1 month to 45 years) and on 534 patients in Toronto (mean +/- SD age 15.2 +/- 8.3, range 1 month to 43 years). Males constituted 57% in the Boston group, 58% in Toronto. Pulmonary function test results were recorded for 64% of the Boston patients and 77% of the Toronto patients. Survival curves for the period 1972-1981 generated by the CF Patient Registry were compared. Patients in Boston tended to be shorter than patients in Toronto. This pattern was seen in both sexes in the 10-20 year age groups. Toronto males also weighed more than Boston males. Mean forced expiratory volume in one second (FEV1) was not different in Boston and Toronto CF patients whether expressed as a percent of predicted or in litres by age groups. Median age of survival in Boston was 21 years, in Toronto 30, the two curves showing a marked separation from age 10. Although progressive pulmonary disease is the major cause of mortality in cystic fibrosis, the differences in growth and survival in these two patient groups, with very similar age-specific pulmonary function, suggest further examination of nutritional guidance and intervention in CF, especially regarding the traditional restriction of dietary fat.

Adolescent↗
PubMed1988

Role of conventional physiotherapy in cystic fibrosis.

Because of the time and the emotional cost involved in performing daily conventional chest physiotherapy in patients with cystic fibrosis, a 3-year prospective study was undertaken to compare the long-term effects of postural drainage accompanied by percussion and the forced expiratory technique with the effects of the forced expiratory technique alone. Patients who performed the forced expiratory technique alone had mean annual rates of decline that were significantly different from zero for forced expiratory volume in 1 second (p less than 0.001), forced expiratory flow between 25% and 75% of vital capacity (p less than 0.001), and Shwachman clinical score (p less than 0.004). In the group performing conventional physiotherapy with percussion and postural drainage, only the mean annual rate of decline for forced expiratory flow between 25% and 75% of vital capacity was significantly different from zero (p less than 0.03), and it was significantly different from the mean rate of decline associated with the forces expiratory technique alone (p less than 0.04). We conclude that conventional chest physiotherapy should remain a standard component of therapy in cystic fibrosis.

Adolescent↗
PubMed1988

Hepatic abscess and cystic fibrosis.

Extrapulmonary infection is rare in cystic fibrosis. We describe two adult patients with cystic fibrosis whose course was complicated by the development of liver abscesses. The possible aetiology of these abscesses is discussed and the diagnosis, treatment and prognosis of pyogenic hepatic abscess is briefly reviewed.

Adult↗
PubMed1988

Cardiopulmonary adaptation at rest and during exercise 10 years after Mustard atrial repair for transposition of the great arteries.

Discordance exists between apparently reduced systemic right ventricular function and the reported asymptomatic state of many patients after atrial repair for transposition of the great arteries. To evaluate this clinical observation, cardiopulmonary response to exercise in 17 asymptomatic patients with no significant postoperative hemodynamic abnormalities was assessed by upright bicycle ergometry according to a modified Jomes protocol 11.5 +/- 1.5 years after Mustard atrial repair. Seventeen age- and sex-matched normal adolescents constituted the control group. Incremental exercise was performed to determine maximum work capacity, heart rate, blood pressure, oxygen saturation, and minute ventilation. Cardiac output was computed at rest and during steady-state exercise by a carbon dioxide rebreathing method at 50% of the maximum workload achieved during incremental exercise. Height and weight were similar in patients and controls (p greater than .05). Resting pulmonary function variables were normal in all subjects. At peak exercise, respiratory quotient was greater than 1 in both patients and controls (1.12 +/- 0.09 and 1.09 +/- 0.08 respectively, p greater than .05). Patients achieved a lower peak heart rate (172 +/- 14 vs 185 +/- 11 beats/min, p less than .01), lower maximum work capacity (2.3 +/- 0.6 vs 3.3 +/- 0.7 W/kg, p less than .01). The ratio of minute ventilation at peak exercise to maximum resting voluntary ventilation was normal (less than or equal to 80%) in both groups. The ventilatory equivalent for oxygen was similar at rest, but significantly higher in patients than in control subjects at peak exercise (42 +/- 7 vs 36 +/- 5, p less than .006).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1988

Emphysema of early onset associated with a complete deficiency of alpha-1-antitrypsin (null homozygotes).

We have compared lung function in 3 subjects with no alpha 1-antitrypsin (alpha 1-protease inhibitor) (null homozygotes) with subjects having the typical deficiency, PIZZ. We identified a 31-yr-old woman, presenting with severe obstructive lung disease, who had no detectable plasma alpha 1-antitrypsin, indicating homozygosity for a "null" (or PI*QO) allele of alpha 1-antitrypsin. Two of her sisters have a similar deficiency, one with an onset of symptoms at 17 yr of age. Because of the likelihood that there are a number of different PI*QO alleles, the type in this family has been named null Mattawa (QOmattawa). All 3 homozygotes have shown a marked deterioration of lung function over a 7-yr period of follow-up. In contrast, lung function tests of 6 age-matched nonsmoking subjects with alpha 1-antitrypsin deficiency, PI type ZZ, showed no abnormalities of lung function. The 15 to 20% of the normal plasma concentration of alpha 1-antitrypsin associated with the PI*Z allele appears to provide some protection to the lung in comparison with a complete deficiency state.

Adult↗
PubMed1988

The effects of chronic airflow limitation, increased dead space, and the pattern of ventilation on gas exchange during maximal exercise in advanced cystic fibrosis.

Although exertional hypercapnea has been observed in patients with advanced cystic fibrosis (CF), the causes have not been fully elucidated. In 14 patients aged 15 to 35 yr of age with advanced CF, the effects of chronic airflow limitation (CAL), increased physiologic dead space (VD), and the timing components of ventilation (VE) on gas exchange during maximal exercise were assessed. The patients were divided into those who retained CO2 during exercise, the CO2R group, and those who did not, the CO2NR group. CO2 retention was defined as a rise in end-tidal CO2 tension of 5 mm Hg or more or to a value greater than 50 mm Hg during a progressive exercise test on a cycle ergometer. CO2 retention occurred in half the subjects, usually by the halfway mark of the test, and did not rise progressively as exercise continued. It was associated with a low VE caused by a low tidal volume (VT) that was the result of a short inspiratory time to total respiratory time ratio (0.33 +/- 0.03 versus 0.38 +/- 0.04, p less than 0.02), whereas there was no difference in mean inspiratory flow or respiratory rate. Although the CO2R group had the worst CAL, with a FEV1 of 28 +/- 7 versus 41 +/- 12% predicted (p less than 0.5) and a FVC of 42 +/- 12 versus 61 +/- 9% predicted (p less than 0.01), the VT at maximal work expressed as a percentage of FVC was lower (45 +/- 13 versus 60 +/- 11, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Cough capacity in patients with muscular dystrophy.

Cough capacity was evaluated in 22 patients with muscular dystrophy (MD) using subjective cough assessment, cough flow-volume curves, maximum expiratory pressures (MEP), forced vital capacity (FVC), and peak expiratory flow rates (PEFR). In ten of the 22 patients transients of peak flow were generated during cough flow-volume maneuvers, indicating dynamic compression of the airways, which is considered important in the physiology of an efficient cough. Patients who could not generate peak flow transients had significantly reduced PEFR, FVC, and MEP values. Measurement of MEP was the most sensitive predictor of flow transient production during coughing; all of the patients who exhibited transients had MEP values of above 60 cmH2O, whereas the highest value of MEP recorded in patients without transients was 45 cmH2O. Three of the 12 patients who were unable to generate flow transients were considered to have an adequate cough by subjective assessment. We concluded that the measurement of MEP is extremely useful for assessment of cough strength in patients with MD.

Adolescent↗
PubMed1988

The approach to chronic cough in childhood.

Chronic cough is a fairly common pediatric complaint. Usually, it is secondary to irritation of the airways following a respiratory viral infection. In these cases, the cough tends to diminish over time. There may, however, be a subsequent development of bronchial hyperreactivity. Asthma is common in the pediatric population. From 50% to 90% of chronic coughers may have hyperreactive airways. In the absence of a pulmonary function laboratory to test for this, a trial of bronchodilator therapy is warranted. Other conditions discussed may also cause chronic cough and a thorough history and physical examination with some simple radiologic investigations can help pinpoint the cause. Specific therapy can then be used to manage the problem. In addition to specific therapy, care must be taken to explain to the parents and patient the physiology of the cough and why it is present. Anxieties and fears should be dealt with in a caring and direct manner. Occasionally, non-specific therapy is needed to allow the parents and child some rest and relief.

Child↗
PubMed1988

Chronic illness and infant-mother attachment: cystic fibrosis.

In order to evaluate the effects of a chronic potentially lethal illness on infant-mother relationships, we assessed 23 infants diagnosed with cystic fibrosis (CF) in the first year of life and 23 healthy controls in Ainsworth's "strange situation" paradigm for attachment at 12-18 months of age. There were no differences in distribution of attachment patterns between the CF infants and the controls, or between either group and published norms. Comparisons between securely and insecurely attached infants in the CF group indicated that, although they did not differ in measures of initial severity of illness, the insecure group was diagnosed significantly earlier and had significantly lower weight and weight for height at 12-18 months. Although the sample is small, these findings point to the possible psychosocial impact of illness and the role that psychosocial factors can play in the health and growth of infants.

Child Development↗