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Biomedical subjects

F Riedel

Publications and source records attributed to F Riedel.

At least 73 records · Page 4Linked to original sources
PubMed1994

Blood eosinophils, leukotriene C4 generation, and bronchial hyperreactivity in formerly preterm infants.

Infants born prematurely are known to display longstanding bronchial hyperreactivity. The mechanism responsible for this is still unclear. Eosinophils are thought to play a central part in the development of bronchial hyperreactivity in asthma. It was the aim of this study to assess the relation of bronchial hyperresponsiveness to potential markers of eosinophilic inflammation in peripheral blood. Eosinophil count, the concentration of serum eosinophilic cationic protein, the capacity of purified eosinophils to generate leukotriene C4, and bronchial reactivity was studied in 24 non-atopic children born prematurely, 12 healthy controls, and 12 children with asthma aged 6 to 9 years. There was no difference in serum concentrations on eosinophil cationic protein and eosinophil counts. However, eosinophils from the 15 formerly preterm infants with significant bronchial hyperreactivity generated significantly higher amounts of leukotriene C4 than normal controls and prematurely born children without bronchial hyperreactivity. Levels of leukotriene C4 in this group were comparable with those obtained with eosinophils from patients with asthma. In contrast with cells from the other groups, eosinophils from the children with bronchial hyperreactivity born prematurely show no enhancement of leukotriene C4 generation on prestimulation with platelet activating factor. It is concluded that bronchial hyperreactivity of children born prematurely is accompanied by the prestimulation of eosinophils.

Asthma↗
PubMed1993

Increase in platelet count following short course therapy with recombinant alpha-2b-interferon in immune thrombocytopenic purpura in childhood.

Two boys, aged three and seven years with immune thrombocytopenic purpura continued to show platelet counts below 20,000/mm3 inspite of treatment with high dose gammaglobulin and steroids. Alpha-2b-interferon injections were followed by normalisation of platelet counts in both patients. No side effects were seen. Alpha-interferon may be a safe and effective treatment for childhood-ITP.

Child↗
PubMed1992

SO2-induced enhancement of inhalative allergic sensitization: inhibition by anti-inflammatory treatment.

Epidemiological studies have shown a relationship between air pollution and allergic airway disease. In a previous study we have found that exposure to SO2 enhances allergic sensitization to inhaled ovalbumin (OA) in the guinea pig. We have now investigated the influence of pre-treatment with anti-inflammatory drugs on SO2-induced enhancement of allergic sensitization in this model. Four groups of 6 guinea pigs each were exposed to 5 ppm SO2 on 5 consecutive days over 8 h per day with intermittent inhalation of OA, while the air-control group was exposed to clean air and OA. During the period of SO2 exposure and sensitization three experimental groups were treated with indomethacin (group I), methylprednisolone (group M) and nebulized nedocromil sodium (group N), while the control group remained untreated. Guinea pigs were investigated for sensitization to OA by specific bronchial provocation tests using body plethysmographic measurement of compressed air (CA) and by measurement of specific antibody response in serum. While in the SO2-exposed control group 5 of 6 animals reacted to specific bronchial provocation testing (CA median 0.15 ml, range 0-0.175 ml), only 1 animal was sensitized in group M (CA 0 ml, 0-0.125, p < 0.05), whereas no bronchial reactions were seen in groups I and N (CA 0 ml, 0-0.05, p < 0.025). Specific IgG antibody titres increased in the control group (median 43 EU-->85 EU), but not in the treatment groups (medians group I 35 EU-->35 EU, group M 30-->35 EU, group N 64-->50 EU).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1990

Relationship between LTC4 generation of hypodense eosinophils and bronchial hyperreactivity in asthmatic children.

In 19 asthmatic children aged 6-16 years, the degree of bronchial hyperreactivity was determined in relationship to the concentration of inhaled histamine which caused a fall of the specific conductance (sGaw) to 60% of the baseline value PC60sGaw. At the time of lung function testing, a sample of heparinized blood was obtained from each patient. Eosinophils were purified and separated into a normodense and hypodense fraction by Percoll gradient centrifugation. After in vitro stimulation by ionophore A 23187, the leukotriene C4 (LTC4) content was determined in the culture supernatants. Hypodense eosinophils of the 13 children with a histamine threshold lower than 1 mg/ml generated significantly (p less than 0.01) larger amounts of LTC4 (0.8-36.3 ng/10(6) cells) when compared to 6 children with a histamine threshold higher than 1 mg/ml (0.7-12.1 ng/10(6) cells) and 12 healthy controls (0.4-8.2 ng/10(6) cells). Preincubation of eosinophils with platelet activating factor (PAF) induced an enhanced LTC4 production, not only in hypodense cells from both asthmatic groups but also in normodense cells from patients with severe hyperresponsiveness. These results are consistent with other results which suggest an important role of eosinophils, their activation by PAF and enhanced release of spasmogenic LTC4 in the pathogenesis of asthma.

Adolescent↗
PubMed1989

Bronchial sensitization in guinea pigs following ingestion of ovalbumin.

Local bronchial mucosal hypersensitivity following antigen feeding was studied in the guinea pig. Groups of 6 animals were fed 1% ovalbumin (OA) in tap water or tap water without antigen (control group) for different feeding periods (14, 28, 42, and 56 days). Inhalative provocations with increasing concentrations of OA (0.5-8% OA) were performed at the end of each feeding period followed by body plethysmographic measurement of airway obstruction. Specific bronchial hypersensitivity to inhaled OA was not found in the control group, whereas specific bronchial reactivity to OA, described as reactivity index, was significantly different from the control group after 14 (p less than 0.05), 28 (p less than 0.001) and 42 days (p less than 0.01) of feeding. No difference to the control group was found after 56 days of feeding. Anti-OA IgG total and IgG1 in serum and bronchoalveolar lavage fluid were increased in OA-fed animals reaching maximal concentrations at day 28 of the feeding period. We conclude that oral feeding of a 1% solution of OA can induce a transient state of local hypersensitivity to inhaled antigen in the guinea pig as manifested by bronchoconstriction on OA inhalation and increased concentrations of local and systemic specific antibodies. This period of local hypersensitivity is followed by tolerance.

Aerosols↗
PubMed1989

Prematurity and maternal bronchial hyperresponsiveness.

Bronchial reactivity was compared among mothers of neonates with unexplained premature delivery and mothers of preterm neonates with known etiology of prematurity as well as mothers who delivered their children at term. Bronchial reactivity was measured by unspecific bronchial provocation testing with histamine. A significantly higher incidence of bronchial hyperreactivity was found among mothers with unexplained prematurity as compared to the control groups. An imbalance in the autonomic nerve system leading to prematurity as well as bronchial hyperresponsiveness is suggested.

Adult↗
PubMed1989

[Effect of passive smoking on bronchial reactivity in school children].

Passive smoking on the part of children leads to an increase in the incidence of upper airway infections in early childhood, an elevated incidence of childhood asthma, and an aggravation of existing asthma. We investigated the bronchial reactivity of 80 healthy, symptom-free schoolchildren, 44 from smoking families (SF), 36 from non-smoking families (NF), employing treadmill exercise during which the subjects inhaled cooled air (-2 degrees C), and compared the results obtained with those found in a group of 27 children with asthma (A). A positive bronchial reaction (50 per cent Raw increase following exercise on the treadmill) was observed significantly more frequently in the SF group than in the NF group (22 out of 44 children as compared with 10 out of 36 children, p less than 0.05); both groups differed significantly from the group of asthmatics (21 out of 27 children). It is concluded that bronchial hyperreactivity occurs more frequently in clinically healthy, passively smoking children as compared with a control group.

Asthma↗
PubMed1988

Effects of SO2 exposure on allergic sensitization in the guinea pig.

The effect of sulfur dioxide (SO2) exposure on local bronchial sensitization to inhaled antigen was studied in the guinea pig. Exposure to SO2 (0.1 to 16.6 ppm) was performed in a 20 L exposure chamber for 8 hours on 5 consecutive days, while temperature, moisture, and concentration of SO2 were monitored and kept constant. SO2 concentrations were measured hourly by Schiff's reaction. On the last 3 days, SO2 exposure was followed by inhalation of nebulized ovalbumin (OA) for 45 minutes. One week later, specific bronchial provocation with inhaled OA (0.1%) followed by plethysmographic measurements of airway obstruction were performed every 2 days during a 2-week period. Specific antibodies against OA were measured in serum and bronchoalveolar fluid by a direct enzyme immunoassay. The SO2-exposed group (N = 17) demonstrated 67% to 100% positive bronchial reactions to inhaled OA, depending on the concentration of SO2, whereas the control group without previous SO2 exposure (N = 14) demonstrated bronchial reactions in only one animal (7%: p less than 0.05). The degree of bronchial obstruction was significantly higher in the exposed group, compared to the control group, for all SO2 concentrations (p less than 0.05). OA-specific antibodies in serum and bronchoalveolar fluid increased in SO2-exposed groups significantly, compared to the control group (p less than 0.05). It is concluded from these results that exposure to SO2 in low and medium concentrations can facilitate local allergic sensitization in the guinea pig.

Aerosols↗
PubMed1987

Long term effects of artificial ventilation in neonates.

In order to evaluate long term effects of artificial ventilation, 27 children, who had been ventilated for more than five days in their neonatal period, were reinvestigated at school age. In 5 of them bronchopulmonary dysplasia had been diagnosed. Seven had more than 10 upper respiratory tract infections per year and 9 had recurrent obstructive airway disease. On pulmonary function testing (n = 23) 19% showed some airway obstruction, and in 43% bronchial hyperreactivity was found by bronchial provocation with histamine. There was a significant correlation (p less than 0.05) between bronchial hyperreactivity and the duration of neonatal ventilation. The degree of hyperreactivity (PC20, FEV1) also correlated with birth weight (p less than 0.005) and gestational age (p less than 0.02). It is concluded that prolonged neonatal ventilation might be followed by bronchial hyperreactivity, especially in the small and premature newborn.

Bronchopulmonary Dysplasia↗
PubMed1987

[Diagnosis of thyroid function in premature infants in intensive care].

In 87 premature infants of an neonatal intensive care unit (gestational age 28-37 weeks) serum-T4, -fT4 and TSH were investigated on day 10, 20 and 30 and at term respectively, in addition to the usual TSH-screening (capillary specimen) on day 5. In 47 neonates (54%) T4 and fT4 were found to be low, including all infants under 30 weeks of gestational age and all ventilated infants. Screening TSH was not elevated but in some cases with iodine contamination. 12 of 13 infants in whom TRH-stimulation was performed showed significant response of TSH. We conclude that compromised thyroid function, common in prematures and infants under intensive care, is similar to the euthyroid sick syndrome in adults and does not require therapy. Replacement of thyroid hormone is only indicated in neonates with increased TSH.

Euthyroid Sick Syndromes↗
PubMed1979

Studies on the structure of isolated chromatin in three different solvents.

Properties of calf thymus chromatin, prepared by mild procedures, have been studied in various solvents. In 0.2 mM EDTA s-values ranged from 20 to 30 S and intrinsic viscosities from 5 to 24 dl/g. Dialysis against 0.15 M NaCl or 0.2 mM MgCl2 changed these values to 80 to 100 S and 0.2 to 5 dl/g, respectively, indicating an essentially more compact structure. In 0.2 mM EDTA X-ray scattering yielded a cross section diameter of 9 nm, which is associated with the tertiary structure of chromatin fiber (M/L = 21200 Dalton/nm). By dialysis against 0.15 M NaCl or 0.2 mM MgCl2 part of the material spontaneously formed quarterny structures (cross section diameters 25-29 nm). The rest of the material with cross section diameters less than 9 nm is supposed to be more strongly sheared tertiary structure which seems to be unable to form quarterny structure due to artificial conformational changes.

Animals↗