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Biomedical subjects

C Shim

Publications and source records attributed to C Shim.

15 recordsLinked to original sources
PubMed1992

Inhibitory effect of purines in meiotic maturation of denuded mouse oocytes.

The potential action of purines, such as hypoxanthine and adenosine, in meiotic arrest was examined using denuded mouse oocytes. The spontaneous meiotic maturation of denuded oocytes was significantly inhibited by hypoxanthine and/or adenosine in a dose-dependent manner. Germinal vesicle breakdown (GVBD) was inhibited even at a low concentration (1 nM) of hypoxanthine, when hypoxanthine was microinjected into the cytoplasm of denuded oocytes. This inhibitory action was potentiated by co-injection with allopurinol, a metabolic blocker of hypoxanthine that can block a metabolic pathway to uric acid. By contrast, a microinjection of adenosine was no longer effective in inhibiting GVBD. Inhibitory action of purines in meiotic maturation was correlated with sustaining intracellular cAMP levels. GVBD was resumed by econazole, one of the nitroimidazole derivatives which act as inhibitors of catalytic subunit of adenylate cyclase. This compound was effective in counteracting the effect of adenosine, but not the action of 3-isobutyl-1-methylxanthine (IBMX) on GVBD, indicating that adenosine is probably exerted at the level of oocyte plasmalemma. These data suggest that the inhibitory action of hypoxanthine and adenosine in oocyte meiotic maturation may be involved in the regulation of cAMP metabolism in a differential manner.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Percutaneous drainage of lung abscess.

Most lung abscesses are successfully treated with antibiotics. However, occasional patients with lung abscesses that drain poorly, causing persistent fever and toxic symptoms, may require surgical intervention. Lobectomy is the most frequent surgical procedure. Some patients are debilitated and have underlying medical conditions such as heart disease, chronic pulmonary disease, or liver disease that may render surgical intervention risky. Recently there have been reports of percutaneous drainage of lung abscess with good results. We have successfully carried out percutaneous drainage of lung abscess in 4 patients and an infected bulla in 1. All patients had failed to respond to therapy with antibiotics and postural drainage. There was prompt disappearance of the fluid level in the cavity, decline in temperature, and abatement of toxic symptoms with drainage. The cavities closed gradually over the next 6-12 weeks. The patients tolerated the chest tube well and there were no side effects from the tube drainage. Percutaneous tube drainage is the surgical treatment of choice in the medically complicated patient with a poorly draining lung abscess.

Adult↗
PubMed1989

Response to bronchodilators.

Bronchodilator response is usually tested to establish reversibility of airflow obstruction, to aid in diagnosis, and to help plan long-term bronchodilator therapy. Among the various tests to establish bronchodilator response, FEV1, FEF25-75% or FEF50%, and FVC are the most widely used. However, it may be difficult to interpret changes in pulmonary function in COPD patients because of day-to-day variability. A 15 per cent increase in FEV1 or FVC and a 30 per cent increase in isovolume FEF25-75% or FEF50% above baseline are acceptable criteria for bronchodilator response. beta-Adrenergic agonists, theophylline, and anticholinergic agents are available for testing bronchodilator response. Inhalation of two puffs of a beta-adrenergic agonist aerosol from an MDI is the most convenient and practical approach for testing in the laboratory. Bronchodilator response is presumed to be beneficial in the treatment of asthma. However, in the treatment of COPD a positive response may not be a reliable guide for establishing long-term benefit.

Adrenergic beta-Agonists↗
PubMed1987

Cough and wheezing from beclomethasone aerosol.

Cough and wheezing are frequent side effects of inhaling beclomethasone dipropionate aerosol (BA) in patients with asthma. Twenty percent of our outpatient asthmatic subjects are unable to take BA due to these side effects. Twelve patients with history of severe cough and wheezing after inhaling BA were tested. Three puffs of either BA or placebo (Plc) were administered from a metered dose inhaler (MDI) in a double-blind crossover design. They coughed a mean of 31 times after BA and 19 times after Plc. Forced expiratory volume in one sec (FEV1) declined a mean of 22.6 percent after BA and 22.0 percent after Plc. Pretreatment with albuterol attenuated both the cough and the drop in FEV1. Follow-up study showed that regular pretreatment with bronchodilator enabled seven of 12 patients to tolerate BA therapy. The remaining five required a short course of increased dose oral steroid therapy. Cough and wheezing are frequent side effects of BA therapy that interfere with regular compliance. Pretreatment with a bronchodilator is effective in attenuating these side effects in some patients; in others, a short course of oral steroid therapy may be necessary.

Aerosols↗
PubMed1987

Lack of effect of hydration on sputum production in chronic bronchitis.

Patients with chronic lung disease productive of sputum are generally encouraged to drink a large amount of fluid to facilitate sputum production. This clinical practice has not been tested systematically. Twelve outpatients with chronic obstructive pulmonary disease in clinically stable condition who had daily sputum production were asked in random sequence: 1) to drink one glass of fluid every waking hour after supper and upon waking the next morning (hydration), 2) to drink no fluid after supper and upon waking the next morning (dry), and 3) to drink fluid ad lib (ad lib). Each morning sputum collection was started upon waking and continued for four hours. The differences in volume, elasticity of sputum, respiratory symptoms, and ease of expectoration were not significant. We conclude that moderate hydration and dehydration have no effect on volume expectorated, the elasticity of sputum, respiratory symptoms or forced expiratory volume in one second.

Aged↗
PubMed1986

Effect of odors in asthma.

Many patients complain that some odors worsen their asthma. Perfume and cologne are two of the most frequently mentioned offenders. Four patients with a history of worsening of asthma on exposure to cologne underwent challenge with a cologne, and their pulmonary function was tested before, during, and after the exposure. Forced expiratory volume in one second declined 18 to 58 percent below the baseline period during the 10-minute exposure and gradually increased in the next 20 minutes. Saline placebo pretreatment did not affect the response to subsequent challenge. Single-blind pretreatment with metaproterenol and atropine prevented decline in one-second forced expiratory volume in three of four patients and blunted the response in the other. Cromolyn sodium prevented decline in one of four, and occlusion of nostrils prevented decline in one of three. A survey of 60 asthmatic patients revealed a history of respiratory symptoms in 57 on exposure to one or more common odors. Odors are an important cause of worsening of asthma.

Adult↗
PubMed1986

Positional effects on distribution of ventilation in chronic obstructive pulmonary disease.

Ventilation is distributed predominantly to the dependent lung in normal persons in the decubitus position. We evaluated the distribution of ventilation in four patients with mild-to-moderate chronic obstructive pulmonary disease using 81mKr gas. Patients were tested in the sitting and right and left decubitus positions with and without the application of positive end expiratory pressure (PEEP). In contrast to findings in controls, ventilation was predominantly distributed to the nondependent lung in patients in the decubitus position. Mean ventilation in the right lung decreased from 51% of the total in the sitting position to 31% in the right decubitus position; it increased with the application of 10 cm PEEP. Reduced ventilation in the dependent lung most likely is caused by closure of the airways after a decrease in volume. Application of PEEP resulted in increased lung volume and preferential distribution of ventilation to the dependent lung.

Aged↗
PubMed1978

Pulsus paradoxus in asthma.

Ninety-three patients with asthma were examined on 308 occasions for systolic fluctuation of blood-pressure during quiet breathing. Pulsus paradoxus (fluctuation of 10 mm Hg or greater) was present on 110 occasions. A pulses paradoxus was associated with greater airflow obstruction (average peak expiratory flow-rate 33.6% of the predicted) than an absent pulsus paradoxus which was associated with a peak expiratory flow-rate of 55.4%. However, pulsus paradoxus was often present in mild obstruction and absent in severe obstruction. In six patients the effect of changing respiratory pattern on systolic fluctuation was studied. Systolic fluctuation was directly related to the inspiratory flow-rate. This is probably one of the major reasons why association of airflow obstruction with pulsus paradoxus is not constant.

Airway Obstruction↗
PubMed1978

Response to corticosteroids in chronic bronchitis.

Corticosteroid drugs are often employed in the treatment of patients with chronic bronchitis. Although some patients respond favorably to such therapy, the characteristics of such patients are not known. Twenty-four patients with chronic bronchitis were treated with prednisone 30 mg daily or placebo for one week each in a double-blind crossover study. The following were monitored before and after each treatment period: physical examination, symptoms, peripheral blood eosinophil count, sputum cell exmination, forced vital capacity (FVC), before and after isoproterenol aerosol. Seven of 24 patients had an FEV1 increase greater than 30% of the control value on prednisone but not on placebo. Blood eosinophil count was elevated (greater than or equal to 350/mm(3)) in 7 patients; 2 of these 7 improved on steroid. Sputum cell examination revealed preponderance of eosinophils in 1, and occasional clumps of eosinophils in 8. Seven of these 9 responded to steroid. Sputum but not blood eosinophilia is a good predictor of a favorable response to steroid therapy.

Aged↗
PubMed1978

Apneusis.

Two cases of apneustic breathing that had several unusual features, as compared with experimental apneusis, are reported here. Both patients had intact vagal function. Respiratory rhythm showed mainly inspiratory apneusis, with a relatively smooth background rhythm. Frequency and duration of apneusis either decreased or were unaffected by breathing CO2, and increased, in one case, after hyperventilation. Both patients were alert and conscious. One had a long history of narcotic abuse, but had no other neurological or respiratory abnormality. Another had been deaf and mute since an episode of meningitis in childhood and had had apneusis for over 35 years, but suffered no other neurological abnormality. These unusual features suggest that the pathogenic mechanisms for apneusis are not the same in experimental models and patients.

Aged↗
PubMed1977

An animal model of cigarette smoking in beagle dogs: correlative evaluation of effects on pulmonary function, defense, and morphology.

Using beagle dogs, we have developed an animal model for the evaluation of the effect of chronic cigarette smoking on pulmonary defense and function and on lung structure. The smoking apparatus developed allows the dog actively to inhale properly diluted (1:4) smoke directly from the cigarette through a mouthpipe. In this model, 6-month and 1-year periods of mild to moderate smoking caused impairment of tracheal mucociliary transport and bacteriosuppressive activity of alveolar macrophages, with little change in pulmonary function. Morphologically, subtle, but significant, lesions were noted in the central airways and bronchiolar walls, consisting of tracheal epithelial basal cell hyperplasia, proliferation of goblet cells in central airways, and peribronchiolar infiltration by inflammatory cells. Morphometry of bronchiolar size distribution, volume proportion of parenchymal structure, and alveolar surface area, however, failed to show significant differences between the groups.

Animals↗
PubMed1975

Cardiac response to repeated doses of isoproterenol aerosol.

We studied 18 patients with moderate to severe asthma for cardiac response to repeated doses of isoproterenol aerosol. In only 1 patient was there a significant increase in heart rate immediately after inhalation of isoproterenol aerosol, and it lasted only for 1 minute. In 2 patients increased heart rate was either due to breathholding or to the propellant in the aerosol. There was no cumulative effect on heart rate. Arrhythmias did not develop at any time despite repeated doses of aerosol every 5 to 20 minutes. Peak expiratory flow rate increased 5 minutes after the first dose, and it increased even further after repeated doses; at no time did it decrease after repeated doses.

Adolescent↗