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Biomedical subjects

D S Postma

Publications and source records attributed to D S Postma.

At least 325 records · Page 18Linked to original sources
PubMed1988

Comparative study of the bronchodilating effects of (-)- and (+)-oxyphenonium bromide.

1. Racemic oxyphenonium bromide, its enantiomers and placebo were inhaled by eight adult patients with chronic airflow obstruction, in a four-way double-blind cross-over study. 2. Forced expiratory volume in one second (FEV1) and slow inspiratory vital capacity (VC) were measured during the first 6 h after inhalation. 3. (+)-Oxyphenonium was found to be the active enantiomer (eutomer), providing better bronchodilation than (+/-)-oxyphenonium. 4. The distomer, (-)-oxyphenonium, showed only a slight effect on FEV1 and VC as compared with placebo.

Adult↗
PubMed1988

The effect of reduction of maintenance treatment on circadian variation in peak expiratory flow rate values in asthmatic children.

We investigated in well controlled asthmatic children whether it is possible to predict by measuring daytime forced expiratory volume in one second, the decline in nocturnal peak expiratory flow rate values after withdrawal of maintenance medication. Forced expiratory volume in one second and peak expiratory flow rate were measured in the outpatient clinic, on the last day with medication. Peak expiratory flow rates were then measured every four hours on days 4, 5 and 6 without medication. Seventeen children showed an amplitude in circadian peak expiratory flow rate values of more than 20% (group I) and nine children showed an amplitude of 20% or less on the three study days (group II). Mean values +/- SEM were 34.7 +/- 2.1% and 10.5 +/- 1.5%, respectively. Forced expiratory volume in one second values were comparable in both groups. Daytime peak expiratory flow rate values before and after withdrawal, remained on the same level in both groups. In group I peak expiratory flow rate values of 24.00 and 08.00 hours on day 6 were significantly lower (p less than 0.05) than on day 4. The results indicate that history and daytime pulmonary function measurements alone, are insufficient to assess the clinical situation and suggest that a decrease in early morning peak expiratory flow rate value (08.00 hours) is an early sign of deterioration of the disease state, after reduction of medication.

Adolescent↗
PubMed1988

Association between nonspecific bronchial hyperreactivity and superoxide anion production by polymorphonuclear leukocytes in chronic air-flow obstruction.

Inflammatory reactions are believed to be important in nonspecific bronchial hyperreactivity (BHR). To investigate the potential role for oxidant-mediated modulation of BHR, we investigated oxidative metabolism of polymorphonuclear leukocytes (PMN) from the peripheral blood in 28 nonallergic patients with chronic air-flow obstruction (CAO). No difference in O2- was found between 14 smokers and 14 ex-smokers with CAO. A significant correlation was found between the degree of BHR and O2(-)-generation of PMN after stimulation with 20 ng/ml phorbol myristate acetate, both in smokers (r = 0.59, p less than 0.01) and in ex-smokers (r = 0.79, p less than 0.01). In the light of other findings in experimental animal studies, the results suggest a direct or indirect role for O2- in the modulation of BHR. Thus, in nonallergic patients with CAO, BHR and inflammation may be linked in a similar way as in allergic patients with asthma.

Adult↗
PubMed1988

Moderately severe chronic airflow obstruction. Can corticosteroids slow down obstruction?

In a former study in patients with severe chronic airflow obstruction (CAO), (forced expiratory volume in one second (FEV1) ranging from 350-910 ml), we concluded that daily oral corticosteroids might slow down the progression of disease. The results of the present long-term (14-20 yr) study on 139 non-allergic patients with less severe CAO (FEV1 greater than or equal to 1200 ml, FEV1 as a percentage of vital capacity (FEV1%VC) 40-55%) confirm and extend our former observations. Four patterns of the course of FEV1 and inspiratory vital capacity (VC) in time were recognized: 1) linear decrease; 2) no change; 3) initial increase, followed by decrease; 4) initial decrease, followed by increase. Groups 1 and 3 had a higher functional residual capacity as a percentage of total lung capacity (FRC%TLC) as compared to group 2 and 4; the work of breathing was lower in group 2 than in the other three groups. Otherwise the initial 82 parameters, including the degree of reversibility of airflow obstruction and smoking habits were comparable in the four groups. The four patterns of FEV1 showed a strong association with the long-term use of prednisolone. When oral prednisolone was instituted or increased to a dose of at least 10 mg/day continuously, FEV1 either remained constant, decreased more slowly or even increased over many years of follow-up. When the oral dose was diminished to below 10 mg/day, FEV1 decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Cochlear blood flow. The effect of noise at 60 minutes' exposure.

The effect of 60 minutes of exposure to high-frequency (10- to 40-kHz), high-intensity (115-dB) noise on the cochlear blood flow (CoBF) was investigated in adult gerbils. The CoBF was measured with a newly improved microsphere method. The number of microspheres in cochlear tissue that had been dissected by the surface preparation technique was assessed by direct counting. Our experiments have indicated that the CoBF is elevated even after 60 minutes of noise exposure. This was true particularly in the areas where these frequencies stimulate the cochlea. The noise also increased CoBF in the opposite ear in areas not corresponding to the stimulation frequencies (second and third turn). This phenomenon is under further investigation.

Animals↗
PubMed1987

Use of steroids and a long-acting vasoconstrictor in the treatment of postintubation croup. A ferret model.

There is little in the literature to support recommendations for the use of steroids and vasoconstrictors in the treatment of postintubation croup. We developed a ferret model to study this condition. Ninety-eight ferrets were used in these experiments, which were undertaken to evaluate the efficacy of steroids and/or a long-acting vasoconstrictor, to develop dose-response curves for dexamethasone sodium phosphate if it proved efficacious, and to evaluate the possible synergistic effects of combination therapy. With this animal model, we were able to document a statistically significant early effect of dexamethasone sodium phosphate, but only when administered in large doses (greater than 0.5 mg/kg). Our data also support the tapering of these large doses within a 20-hour period. The long-acting vasoconstrictor oxymetazoline hydrochloride has a clear and statistically significant beneficial effect that is apparent by 20 hours and continues through 40 hours. We did not find any additive or synergistic effect of the combination of dexamethasone and oxymetazoline. Further studies are underway in our laboratory to elucidate other aspects of this interesting syndrome.

Animals↗
PubMed1987

DNA flow cytometry as a prognostic indicator in head and neck cancer.

The prognostic significance of deoxyribonucleic acid (DNA) flow cytometry has been investigated for many solid tumors, but few data have been accumulated for squamous cell carcinomas of the head and neck. To our knowledge, we report the largest number of patients (69) with head and neck primary carcinomas to be studied by DNA flow cytometry. In the first part of this study, we reviewed 109 consecutive patients with laryngeal or hypopharyngeal primary carcinomas which were treated at North Carolina Memorial Hospital during the period of 1981 to 1984. The final analysis comprised 139 DNA histograms (mean coefficient of variation: 8.02) on paraffin-embedded specimens from 48 patients. Of the 48 patients with primary carcinomas, 24 had glottic, 18 had supraglottic, and 6 had carcinomas from the piriform sinus. Patients had follow-up for a minimum of 12 months, with a mean follow-up period of 23 months. Twenty-three of the 48 primary carcinomas (48%) were clearly aneuploid, and the remaining 52% were tetraploid (22%) or diploid (30%). We have concluded that patients with clearly aneuploid primary carcinomas had significantly better prognoses than those with diploid tumors (p = 0.008). High DNA amounts (greater than 40% of cells beyond the diploid peak, DNA G1G0) also correlated with a favorable prognosis when compared with low DNA amounts (p less than 0.01), and this remained significant when the clinical outcome was adjusted for staging of the primary site (T), nodal status, and stage of disease. Ploidy was the most significant prognostic variable for the laryngeal group of patients. In the second part of the study, twenty-one patients with oral cavity squamous cell carcinomas were studied in a similar fashion as the group with laryngeal carcinomas. In this group, a low DNA amount, with 40% as the cutoff point, was associated with a favorable prognosis (p = 0.024), and this remained significant while controlling for T, nodal status, and stage of disease. Numbers were too small to permit evaluation of the impact of ploidy in this group, but there was a slight trend toward aneuploidy and tetraploidy, correlating with a poor treatment outcome (p = 0.228). DNA amount was the most significant prognostic variable for the group of patients with oral cavity carcinomas.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

The beta-adrenergic system of non-allergic patients with chronic airflow obstruction and early morning dyspnoea.

Lymphocyte beta-adrenergic receptor function and urinary excretion of catecholamines were measured in eight non-allergic patients with partially reversible chronic airflow obstruction (CAO) and early morning dyspnoea (EMD), and in eight matched healthy control subjects. In order to establish a possible relationship between the early morning dyspnoea and a reduced beta-adrenergic activity, these parameters were measured during the "morning dip" in FEV1 and in the afternoon, when lung function is maximal. No differences were observed for lymphocyte beta-adrenergic receptor characteristics (beta-receptor number, Kd, for 3H-dihydroalprenolol, and cAMP response to isoproterenol) between patients and controls, when determined at 8 AM or at 4 PM. Nor was there a significant circadian variation in these parameters present in both groups. By contrast, the patients showed a significantly reduced urinary excretion of epinephrine and norepinephrine, as measured in four-hourly urine portions collected between 8 and 12 AM and between 4 and 8 PM, respectively. In addition, the urinary excretion of epinephrine showed a significant circadian variation in the patients, which was correlated with the FEV1 (% predicted). Such a relationship was not found for norepinephrine. The results suggest that a (generalized) dysfunction of the beta-adrenergic receptor is not involved in the pathogenesis of CAO or EMD. However, reduced beta-adrenergic receptor stimulation due to decreased levels of catecholamines may contribute to the observed (variation in) airflow obstruction of the patients.

Adult↗
PubMed1987

Presentation and management of postcricoid hemangiomata in infancy.

Phillips and Ruh (1912) were the first to describe a congenital hemangioma of the larynx. Sweetser subsequently classified laryngeal hemangiomata into infantile and adult types and noted differences in incidence, location, and symptoms. According to Sweetser, the infantile form is less common, is almost always subglottic, and presents with stridor which may be intermittent. The adult form is somewhat more common, is generally supraglottic, and often presents with hoarseness or dysphagia. We present what we believe is the first reported case of a postcricoid hemangioma in an infant. A review of hemangiomata of the aerodigestive tract is presented and treatment is discussed.

Cricoid Cartilage↗
PubMed1986

Significance of ploidy in laryngeal cancer.

We studied 48 patients with laryngeal or hypopharyngeal primary tumors with DNA flow cytometry. Twenty-four of the tumors were glottic, 18 were supraglottic, and 6 were from the pyriform sinus. Patients were followed for a minimum of 12 months, with a mean follow-up of 23 months. Twenty-three of the 48 primary tumors (48 percent) were clearly aneuploid, 22 percent were tetraploid, and 30 percent were diploid. We concluded that patients with aneuploid primary tumors, high DNA levels, or both have a significantly better prognosis than those with diploid tumors, and this remained statistically significant when clinical outcome was adjusted for tumor status, stage, and nodal status.

DNA, Neoplasm↗
PubMed1986

Influence of slow-release terbutaline on the circadian variation of catecholamines, histamine, and lung function in nonallergic patients with partly reversible airflow obstruction.

In order to study the mechanism underlying early morning dyspnea in patients with chronic airflow obstruction, the relation was assessed between the diurnal variation of FEV1, plasma and urinary catecholamines, and urinary histamine (metabolites) in eight nonallergic patients (mean age, 53 years). These parameters were measured both after administration of placebo and slow-release terbutaline tablets during 1 week. The fall in FEV1 at 4 A.M. coincided with a fall in both plasma and urinary epinephrine levels, whereas no correlation between pulmonary function and norepinephrine levels was observed. Histamine and N tau -methylhistamine excretion were found within the normal range without a circadian rhythm, suggesting no important role for histamine in the occurrence of early morning dyspnea in this nonallergic patient group. Administration of slow-release terbutaline during 1 week prevented the nocturnal fall in FEV1. Terbutaline treatment suppressed plasma and urinary levels of epinephrine significantly without any effect on norepinephrine. We conclude that epinephrine appears to be an important factor in the regulation of the bronchial smooth muscle tone in patients with early morning dyspnea.

Adult↗
PubMed1986

Effect of manual percussion on tracheobronchial clearance in patients with chronic airflow obstruction and excessive tracheobronchial secretion.

The effect of manual percussion of the thorax in nine patients with stable chronic airflow obstruction and excessive tracheobronchial secretion has been studied. Tracheobronchial clearance was measured over 50 minutes on three different days. On the first day manual percussion was applied for 10 minutes. In the period when percussion was applied the mucus clearance was slightly but significantly greater than in the periods when no percussion was applied. On the second day manual percussion was applied in combination with postural drainage, coughing, and breathing exercises for 20 minutes. This resulted in a much greater clearance than on the first day. On the third day postural drainage, coughing, and breathing exercises, but no manual percussion, were carried out for 20 minutes. There was no significant difference between the clearance of days 2 and 3. From this study it is apparent that manual percussion is a relatively ineffective procedure in patients with stable chronic airflow obstruction, but may be useful when the patient is not able to cough and cannot assume the appropriate position for postural drainage.

Aged↗
PubMed1986

Independent influence of reversibility of air-flow obstruction and nonspecific hyperreactivity on the long-term course of lung function in chronic air-flow obstruction.

We evaluated factors that might influence the course of lung function after 2 to 21 yr of follow-up in 81 nonallergic patients with chronic air-flow obstruction (CAO) and considerable lung function impairment (initial forced expiratory volume in one second as a percentage of inspiratory slow vital capacity (FEV1 % VC) ranging from 40 to 55% and increasing less than 15% after the administration of the anticholinergic bronchodilator thiazinamium). A more favorable rate of change in FEV1 was associated with less pack-years of smoking, less nonspecific hyperreactivity, and a higher degree of reversibility of air-flow obstruction, when expressed as the increase in FEV1 as a percentage of the predicted minus prebronchodilator FEV1 value. Nonspecific hyperreactivity and reversibility of air-flow obstruction appeared to influence the decline in FEV1 independently of baseline value of FEV1, both in smokers and ex-smokers. The hypothesis is put forward that regular bronchodilating therapy may be able to prevent deterioration of lung function. However, the possibility that interval therapy may ultimately produce the same results cannot be excluded. It seems to be important to stop smoking, both for the sake of its negative influence on the course of FEV1 and for the fact that a beneficial influence of bronchodilating therapy may become even more apparent.

Adult↗
PubMed1986

The surgical exposure of penetrating injuries to the carotid artery at the skull base.

Injuries of the internal carotid artery at the skull base present complex technical problems for the surgeon. Exposure is difficult, distal control of the vessel for shunting or repair is frequently impossible, and thus ligation of the ICA is often necessary as definitive treatment. Three cases involving penetrating injury to the carotid artery at the skull base are presented. The issue of primary repair vs. ligation for carotid injuries is briefly addressed, and the various methods of surgical exposure of the distal extracranial ICA are reviewed.

Adult↗