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Biomedical subjects

D S Postma

Publications and source records attributed to D S Postma.

At least 307 records · Page 17Linked to original sources
PubMed1990

Metastasizing pleomorphic adenoma with myoepithelial cell predominance.

The biological behavior of pleomorphic adenomas (mixed tumors) of salivary gland origin is complex. Tumors with benign histologic features may exhibit recurrence and locally aggressive behavior especially after incomplete excision. A small percentage of pleomorphic adenomas have obvious malignant components in epithelial or in both epithelial and mesenchymal components and can metastasize. There are also rare case reports which appear to document typical pleomorphic adenomas of salivary gland with histologically identical visceral and lymph node metastases. Recently myoepithelial cell proliferation has been identified as a possible predictor of aggressive clinical behavior in otherwise histologically benign pleomorphic adenomas. We report such a parotid gland lesion with local recurrence and retroperitoneal spread. DNA-flow cytometry of cells from the paraffin-embedded primary and metastasis showed similar aneuploid populations. Aneuploidy appeared to reflect the malignant potential of this particular pleomorphic adenoma and suggests that DNA-flow cytometry of salivary gland tumors may yield important prognostic information.

Adenoma, Pleomorphic↗
PubMed1990

Effect of forced expirations on mucus clearance in patients with chronic airflow obstruction: effect of lung recoil pressure.

Spontaneous mucus clearance and the effect of forced expirations and coughing on mucus clearance were investigated in eight patients with chronic airflow obstruction and low elastic recoil pressure (emphysema group: mean FEV1 45% predicted) and in seven patients with chronic airflow obstruction and normal elastic recoil pressure (chronic bronchitis group: mean FEV1 57% predicted). Mucus clearance was measured in a central and a peripheral lung region by a radioactive aerosol tracer technique. Spontaneous mucus clearance from the peripheral lung region was higher in the patients with emphysema than in those with chronic bronchitis. There was no difference in central mucus clearance between the two groups. Mucus clearance from the peripheral lung region increased significantly during forced expirations and coughing in the patients with chronic bronchitis but not in those with emphysema. It is concluded that in patients with chronic airflow obstruction and regular sputum production spontaneous peripheral mucus clearance is greater in those with decreased elastic recoil pressure. Physiotherapy that includes forced expirations and coughing can enhance mucus clearance in such patients when elastic recoil pressure is normal but is unlikely to be effective when elastic recoil pressure is decreased.

Adult↗
PubMed1990

[Nocturnal asthma in children, symptoms and treatment].

Nocturnal airflow obstruction is a common symptom in children with asthma. The increase in airflow obstruction overnight is underassessed by children as well as their parents. Worsening of the early morning peak flow values may be an indication for an increase in airflow obstruction overnight. An increase in vagal activity does not, in contrast with the observations in adult patients, contribute to the development of nocturnal airflow obstruction in asthmatic children. However, a nocturnal increase in inflammatory mediators seems to play a role of importance. Treatment of nocturnal airflow obstruction should therefore be focussed on inflammatory processes in the lungs.

Airway Obstruction↗
PubMed1990

[CARD from childhood to adulthood].

In approximately 50 per cent of the children with asthma respiratory symptoms, these symptoms disappear during puberty. Outgrowing childhood asthma is especially estimated by: the degree of airway obstruction as a child, and the degree of bronchial hyperreactivity in childhood. Another childhood factor of influence on the prognosis of asthma seems to be the combined early and late bronchial response after inhalation of an allergen. Factors not predicting the outcome of childhood asthma are: at what age asthma symptoms started; whether the child with asthma had eczema or not, and how strong skin-allergy was. Conceivable risk-factors for the outcome of childhood asthma are: smoking of the parents and a strong degree of eosinophilia. The prognosis of asthma might be improved by more intensive treatment and continuity in treatment of the children with an increased risk.

Adolescent↗
PubMed1990

Effects of corticosteroids in "chronic bronchitis" and "chronic obstructive airway disease".

In order to improve our knowledge concerning the supposedly beneficial effects of corticosteroids in patients with "chronic bronchitis" and "chronic obstructive airway disease" (COAD), it is necessary to define our patients carefully, so that every investigator can interpret the data adequately. Up to now, no definite conclusion can be drawn as to the profitable effect of corticosteroids in COAD. A combination of data from many studies on oral and inhaled corticosteroids strongly suggests that long-term studies in large groups of patients are essential if we wish to determine a potential treatment effect. In this way, a sub-group of patients who improve on corticosteroids may be found too. In addition to objective measurements, e.g. degree of airflow obstruction and airway hyperresponsiveness (AH), subjective data and information on the patient's quality of life and exacerbations should be included for evaluation.

Adrenal Cortex Hormones↗
PubMed1989

The reproducibility and agreement of three indices of airway responsiveness to histamine in asthmatic children.

In 12 asthmatic children, aged 8-14 years, we investigated the possibility of using a provocation concentration of histamine (PC) causing a 10% or 15% fall in baseline forced expiratory volume in 1 sec (FEV1), instead of a PC20 histamine, in the assessment of bronchial hyperreactivity. Inhalation challenge tests were performed on days 6 and 7 after withdrawal of medication. PC10, PC15, and PC20 were calculated from the dose-response curves. Reproducibilities for PC10, PC15, and PC20 values for both days, determined by Student's t-test, were not significantly different. Correlation coefficients between PC20 and PC15 values on days 6 and 7 and between PC10 values on days 6 and 7 were 0.82 and 0.76, respectively; between PC20 values on day 6 and PC15 values on day 7; and between PC20 values on day 6 and PC10 values on day 7 they were 0.84 and 0.82, respectively. (P less than 0.01 for all r values). The predictive value of PC20 for PC10 and PC15 was determined by a least-squares regression line with 95% confidence intervals. Variances between PC10, PC15, and PC20 were not significantly different on either day 6 or 7. Our data show that a PC10, as well as a PC15, can be used in the assessment of the degree of bronchial hyperreactivity in children with asthma.

Adolescent↗
PubMed1989

Association between nonspecific bronchial hyperreactivity and superoxide anion production by polymorphonuclear leukocytes in chronic airflow 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 airflow obstruction (CAO). No difference in O2- generation 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). The results suggest that oxygen radicals in a direct or indirect way may modulate BHR. Thus, in nonallergic patients with CAO, BHR and inflammation may be linked in a similar way as in allergic patients with asthma.

Aged↗
PubMed1989

Circadian change in bronchial responsiveness and airflow obstruction in asthmatic children.

To throw light on the question of whether the increase in bronchial responsiveness seen during the night is due to increased airflow obstruction, nine asthmatic children with increased airflow obstruction at night (group 1) were compared with nine without (group 2). The mean fall in forced expiratory volume in one second (FEV1) between 16.00 and 04.00 hours was 21.9% in group 1 and 2.3% in group 2. Selection of patients was based on the amplitude of change in peak expiratory flow (PEF) measured every four hours for three consecutive days at home. The study was performed in hospital on four consecutive days. Medication was withheld for three days before and during the measurements at home and in hospital. On the first day in hospital (day 4) FEV1 was measured every four hours for 24 hours. On day 6 inhaled histamine provocation tests were performed at the same times as the FEV1 measurements on day 4. Both groups showed a nocturnal fall in the provocative dose of histamine causing a 20% fall in FEV1 (PC20). The mean change in histamine PC20 from 16.00 to 04.00 hours was 1.1 doubling doses of histamine in group 1 and 1.5 doubling doses in group 2. The results indicate that the increase in nocturnal bronchial responsiveness that occurs at night is not due to an increase in airflow obstruction.

Adolescent↗
PubMed1989

Prognosis of chronic obstructive pulmonary disease: the Dutch experience.

This article summarizes the Dutch experience with prognosis in three groups of patient with chronic obstructive pulmonary disease. (1) 129 patients with severe chronic airflow obstruction (mean FEV1 1,880 ml, range 1,200 to 2,500 ml); (3) 81 patients out of group 2 with decline in FEV1 over time, without oral corticosteroids. It is clear that, at least in the presence of regular therapy, next to cessation of smoking, a higher reversibility of airflow obstruction and lower degree of airway hyperreactivity are important predictors of a slower decline in FEV1. In our opinion these findings point to the urgency for clinicians to change the nihilistic attitude towards patients with CAO, in that both smoking cessation and an early therapy directed at the reversible part of airflow obstruction and airway hyperreactivity may be able to prevent deterioration. Future studies have to show whether long-term, ongoing therapy with corticosteroids may even change the progression and survival in far advanced disease.

Adrenal Cortex Hormones↗
PubMed1989

Prognosis of asthma from childhood to adulthood.

The outcome of childhood asthma was studied in 101 adults who came from a group of 119 asthmatic children (85%) 6 to 14 yr of age who had originally been investigated between 1966 and 1969. Changes in respiratory symptoms, spirometry, and airway responsiveness to histamine in childhood and adult life were analyzed. It was found that 43 of the 101 adults (43%) had current symptoms; 29 of the 43 (67%) were receiving maintenance therapy. In the first study, 83 of the 101 children (82%) showed a response on inhalation of histamine (PC10-histamine less than or equal to 16 mg/ml). The number of subjects in the second study who still had a PC10-histamine less than or equal to 16 mg/ml fell to 29, suggesting that airway responsiveness decreases from childhood to adulthood. During the second survey (in adults), 25 of the 43 (59%) subjects with current symptoms and four of the 58 (7%) without respiratory symptoms responded to histamine. Adults with current symptoms had a significantly lower %FEV1 in both childhood and adulthood than did adults without current symptoms; %FEV1 was not different in females and males or in smokers and nonsmokers in either the first or the second survey. The outcome of childhood asthma is primarily predicted by the initial degree of bronchial obstruction (p = 0.041) and airway responsiveness to histamine (p = 0.050), and does not appear to be related to sex, smoking habits, or age of onset of respiratory symptoms.

Adolescent↗
PubMed1989

A prospective randomized study of four commonly used tympanostomy tubes.

Tympanostomy tube placement has clearly been shown to be an efficacious treatment for recurrent bouts of acute otitis media or chronic otitis media with effusion. However, there are few objective, prospective, randomized studies present in the literature to aid the clinical otolaryngologist with the proper tube choice for middle ear aeration. A prospective, randomized study was undertaken of four commonly used tympanostomy tubes. Shepard Teflon grommet, Armstrong beveled tube, Reuter-Bobbin tube, and Goode T-tube. This study was undertaken to determine which of these tubes had the fewest number of postplacement complications, including otorrhea, plugging, residual perforation, or chronic persistence in the tympanic membrane. Average follow-up was 17 months. The Shepard and Armstrong tubes showed a comparatively low rate of plugging and otorrhea. Both tubes had extrusion times that averaged less than 1 year. The Reuter-Bobbin tube had a much greater rate of plugging, compared to the other tubes. The T-tube had an increased incidence of otorrhea and persistence in the tympanic membrane well beyond 1 year. The T-tube was also the only tube in this study associated with residual perforations.

Adolescent↗
PubMed1989

Pulmonary function in patients presenting with Raynaud's phenomenon without an underlying connective tissue disease. A prospective, longitudinal study.

Forty-two patients presenting with Raynaud's phenomenon (RP) were prospectively evaluated for pulmonary function changes over a 6-year followup period. Fifteen patients had secondary RP at presentation, 27 patients had nonsecondary RP. In the latter group, decreased pulmonary diffusing capacity (Tlco) was observed in only 2 patients (7%) whereas 9 patients with secondary RP (60%) had decreased Tlco. In the group of patients with nonsecondary RP exhibiting one or more autoantibodies, Tlco values were lower than in the group without autoantibodies (p less than 0.01). In patients with nonsecondary RP the duration of disease was correlated with the level of Tlco (r = 0.55), probably explained by a higher prevalence of truly primary RP in patients with longstanding nonsecondary RP. During followup no significant changes in pulmonary function were observed in the group with nonsecondary RP. We conclude that pulmonary function testing in patients presenting with nonsecondary RP without autoantibodies does not appear of clinical value.

Adult↗
PubMed1988

Magnesiuric and calciuric effects of terbutaline in man.

1. The effect of terbutaline infusion over 4 h on serum levels of potassium, ionized calcium, phosphate and magnesium and urinary excretion of potassium, calcium, magnesium and adenosine 3':5'-cyclic monophosphate was studied in six healthy volunteers. 2. Serum levels of potassium, calcium, phosphate and magnesium decreased. Urinary excretion of potassium decreased, whereas those of calcium, magnesium and adenosine 3':5'-cyclic monophosphate increased. 3. These results indicate that the hypocalcaemic and hypomagnesaemic effects of terbutaline can, at least partly, be explained by enhanced urinary excretion of calcium and magnesium. This may have important implications for the short-term terbutaline treatment of patients with, for example, cardiac disease.

Adult↗