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Biomedical subjects

T Nicolai

Publications and source records attributed to T Nicolai.

At least 55 records · Page 3Linked to original sources
PubMed1996

The effect of temperature and ionic strength on the dimerisation of beta-lactoglobulin.

Bovine beta-lactoglobulin is a globular whey protein that associates partly and reversibly in dimers in the native state. Static and dynamic light scattering techniques have been used to determine the relative amount of monomers and dimers, and to estimate their size and shape in different conditions. The effect of the ionic strength on the dimerisation has been studied at pH 2, where the protein is highly charged. A simple model, taking into account the monomer-dimer equilibrium and virial interactions has been used. The strength of the interactions depends on the amount of added salt, i.e. ionic strength, and influences the dimer dissociation. When the ionic strength decreases, the equilibrium is shifted towards the monomeric form. The dissociation, however, is only complete at very low concentration. The effect of temperature has been studied at pH 7 and low concentration where virial interactions are negligible. The dissociation increases with increasing temperature (5 degrees C - 76 degrees C). At high temperatures, protein-protein aggregation is fast, even at low concentration. The temperature dependence can be described using a simple Van't Hoff model, even at temperatures where aggregation occurs. The ionic strength and temperature dependence both indicate that beta-lactoglobulin solutions have to be considered as a mixture of monomers and dimers.

Hydrogen-Ion Concentration↗
PubMed1996

Respiratory hypersensitivity and environmental factors: East and West Germany.

We assessed the prevalence of asthma and allergic disorders in 9-11 year old children in Leipzig and Halle in East Germany, and Munich, West Germany. Both East German cities were heavily polluted due to private coal burning and industrial emissions, whereas Munich has moderate industry but heavy car traffic. All fourth grade pupils in Munich (n = 7445) were compared with those in Leipzig, 1990 (n = 1429) and Leipzig and Halle, 1991 (n = 3105). The prevalence of hay fever and skin test reactivity to common aeroallergens was considerably higher in West Germany as compared to East Germany. Furthermore, the prevalence of asthma was also higher in the West German study area. However, when atopy was taken into account, there was no longer a significant difference in the prevalence of asthma between the two parts of the country.

Air Pollutants↗
PubMed1996

Psychosocial characteristics of asthma.

The objective of this study was to compare psychosocial characteristics of children with asthma and children with bronchial hyperreactivity with those of normal children. A population-based study of 2634 children (mean age, 10 years) was carried out. Pulmonary function tests of children were performed in children before and after cold air hyperventilation challenge to determine bronchial hyperreactivity. Parental assessment of children's behavior was evaluated with 15 questions about school/learning habits, level of activity, communication/affection, and sleeping patterns. A factor analysis was performed and the factor loading adjusted for confounders compared in the different groups. Asthmatic children sleep less well than normal and hyperreactive children (p < 0.001). Unexpectedly, however, all other single items did not differ significantly. As a result of the factorial analysis we obtained two factors. On the first factor, measuring school behavior and learning, there was a small difference between asthmatic and normal children, which could not be found on the second factor indicating activity and communication. We conclude that psychosocial differences of asthmatic children are less remarkable than expected. As a result of the examination of the hyperreactive children it is likely that asthmatic children are influenced more by secondary psychosocial factors than by any primary effect of asthmatic disease.

Asthma↗
PubMed1996

[Fatal complications in tracheotomized children].

BACKGROUND: Tracheotomy in the pediatric patient has become a routine procedure since the late 19th century, when it was used in treating diphtheria. Although underlying diseases have changed, the child with an artificial airway still faces numerous risks. This study investigates fatal complications in 280 patients with tracheostomy who were seen in the Dr. von Haunersches Kinderspital for laryngo-tracheo-bronchoscopy. METHOD: Data was acquired from patients' records of the Dr. von Haunersches Kinderspital and communications with other institutions. RESULTS: Nineteen deaths were investigated. Three patients died of acute cannula obstruction although hospitalized in different institutions. Two patients who died at home may also have suffered cannula obstruction, although this could not be verified. The majority of patients succumbed to the underlying disease. CONCLUSIONS: Permanent close supervision or monitoring at all times is critical to prevent cannular related deaths. Our results are compared with major series in other studies. In addition, we propose a booklet for the pediatric tracheotomy patient to document patient data and examination findings, e. g. type and size of cannula, duration of cannulation, laryngotracheometry, and complications. Its purpose will be to support communication between patients, parents, pediatricians, pediatric surgeons, and otolaryngologists. Furthermore, this booklet will help in evaluating risks, which may encounter pediatric tracheostomy patients, thereby enabling future studies.

Adolescent↗
PubMed1996

Risk of asthma in children with a history of croup.

All fourth-grade school children in Munich and the surrounding districts (age 9-11 years, n = 9403) were surveyed with a questionnaire, lung function testing and bronchial provocation. Croup was reported in 9.8%. In these children, lung function was decreased even after controlling for asthma and other confounding factors. Only recurrent croup had an increased prevalence in children with asthma. When a family history for asthma, maternal smoking and social status were included into a logistic multiple regression model, the odds ratio to develop asthma was 2.91 (confidence interval (CI) 2.19 - 3.86) for children with a history of croup, 2.60 (CI 1.93 - 3.51) for a family history for asthma and 8.60 (CI 4.99 - 14.80) for the combination of family history and croup. Asthma was diagnosed in 37.3% of children with croup and a positive family history.

Asthma↗
PubMed1996

Familial aggregation of asthma in a South Bavarian population.

There is considerable evidence for a significant hereditary component in the pathogenesis of asthma and allergic diseases. The objective of this study was to investigate familial influences unique to the expression of asthma. School children (n = 9,403), 9 to 11 yr of age, were enrolled in a cross-sectional survey in southern Germany. The prevalence of asthma and allergic diseases in parents and children was assessed through parental questionnaires. Atopic sensitization was measured by skin prick tests, and bronchial responsiveness was determined by cold air hyperventilation challenge. The prevalence of asthma alone, i.e., without concomitant hay fever or atopic eczema, increased strongly if nearest of kin suffered from asthma alone (4.7 versus 11.7%, p < 0.0001). A family history of hay fever or atopic dermatitis, excluding asthma, was unrelated to asthma in the offspring (4.7 versus 3.9%). These relations did not change when stratifying for skin prick test reactivity (STR) and bronchial hyperresponsiveness (BHR). STR alone and BHR alone (i.e., without manifestation of disease) were unrelated to a family history of asthma or allergy. The results strongly suggest a separate genetic factor controlling the development of asthma. Skin test positivity and BHR to cold, dry air are unlikely to be the underlying mechanisms through which the inheritance of childhood asthma is transmitted.

Asthma↗
PubMed1995

Pulmonary sling: morphological findings. Pre- and postoperative course.

Pulmonary sling (PS) is a congenital condition in which the left pulmonary artery (LPA) arises from the right pulmonary artery (RPA), forming a sling around the trachea causing tracheal compression. The incidence is not so rare as initially thought. Symptoms of severe airway obstruction often begin in the newborn or young infant. Echo-colour-Doppler may reveal the PS but emphysema can mask the typical findings. Deviation of fluid-filled lungs may be detected prenatally. Chest radiographs show unusual air distribution, deviation of heart and mediastinum and altered tracheobronchial angles. Bronchography and bronchoscopy demonstrate the high incidence of associated tracheal anomalies such as cartilagenous rings and long tracheal stenosis. Anterior oesophageal indentation is not always seen in the oesophogram. Magnetic resonance imaging (MRI) and computed tomography (CT) reveal the PS, but cautious interpretation is necessary because of different levels of the anomalous LPA. PS and associated cardiovascular malformations can be clearly detected by angiography. Associated extrathoracic anomalies are common. Early diagnosis and therapy of PS is mandatory and consists of reimplantation of the LPA into the pulmonary trunk and division of the ligamentum arteriosum. The postoperative course may be cumbersome necessitating bronchological interventions. Tracheal resection may be necessary but restenosis is frequent. A one-stage repair has been proposed in such cases and was successfully done in a few reported cases. Relief of respiratory obstruction is often complete when there are no associated tracheobronchial anomalies. Late postoperative course is favourable but respiratory obstructive attacks may occur with decreasing incidence over time and tracheal growth.

Abnormalities, Multiple↗
PubMed1994

Skin test reactivity and number of siblings.

OBJECTIVE: To investigate the relation between skin test reactivity in children and number of siblings. DESIGN: Cross sectional survey among schoolchildren aged 9-11 years. Skin prick tests in the children and self completion of written questionnaire by their parents. SUBJECTS: 5030 children in Munich and 2623 children in Leipzig and Halle, Germany. MAIN OUTCOME MEASURES: Atopic status assessed by skin prick tests. RESULTS: After possible confounders were controlled for, the prevalence of atopic sensitisation decreased linearly with increasing number of siblings (odds ratio = 0.96 for one sibling, 0.67 for five or more siblings; P = 0.005). In atopic children the severity of the skin test reaction as assessed by the weal size was not associated with the number of siblings. CONCLUSIONS: Factors directly or indirectly related to the number of siblings may decrease the susceptibility of children to become atopic. Thus, declining family size may in part contribute to the increased prevalence of atopic diseases reported in Western countries over the past few decades.

Child↗
PubMed1994

Prevalence of asthma and atopy in two areas of West and East Germany.

The German reunification offers a unique opportunity to study the impact of environmental factors on the development of childhood respiratory and allergic disorders in ethnically similar populations. We investigated the prevalence of asthma, hay fever, atopy, and bronchial hyperresponsiveness (BHR) in 9- to 11-year old children in West Germany (n = 5,030) and East Germany (n = 2,623). A self-administered questionnaire was distributed to the parents. Children underwent cold air challenge and allergy skin prick tests. Atopic sensitization was considerably more frequent in West German children than in their peers in East Germany (36.7% versus 18.2%; odds ratio [OR] = 2.6, p < 0.0001). The prevalence of current asthma and hay fever was significantly higher in West Germany when compared with that in East Germany (5.9% versus 3.9%; OR = 1.5, p < 0.0001 and 8.6% versus 2.7%; OR = 3.4, p < 0.0001, respectively). Bronchitis, however, was more prevalent in East Germany than in the western part of the country. The prevalence of BHR as assessed by cold air challenge was higher in West Germany compared with that in East Germany (8.3% versus 5.5%, OR = 1.6, p < 0.001). Logistic regression showed that the West German study area was no longer a significant independent determinant of asthma once sensitization to mites, cats, and pollen was taken into account. We conclude that sensitization to aeroallergens is strikingly more frequent in West Germany than in East Germany and this may explain the differences in the prevalence of asthma and hay fever between the two parts of the country.

Asthma↗
PubMed1993

[Bronchial asthma in childhood. Part 2: Prevention and step-wise plan for drug therapy].

On the basis of our knowledge of the pathogenesis of bronchial asthma, prophylactic measures and systematic treatment are of decisive importance. In the first instance, prophylactic measures cover the elimination of allergens and avoidance of exposure to tobacco smoke. Drug treatment of bronchial asthma should be initiated early on, be planned for the long-term, and comprise an individually matched combination of anti-inflammatory agents and drugs with an acute action. Here, inhalative steroids are of great importance in children, too. Drug therapy and physical measures should be applied systematically in a stepwise fashion tailored to the clinical severity of the symptoms. Additional instruction of the patients in respiratory techniques is also needed.

Administration, Inhalation↗
PubMed1993

[Bronchial asthma in childhood. Part 1: Clinical manifestations, diagnosis and ground rules of therapy].

The most common disease met with in childhood is bronchial asthma, the prevalence of which in Germany is reported to be as high as 8%. However, the true figure is likely to be considerably higher. Bronchial asthma is defined as a variable, episodic airways obstruction that is accompanied by hypercontractility of the bronchial system. Instead of the characteristic wheezing, in childhood the disease often presents as untypical attacks of coughing. In the differential diagnosis, aspiration of a foreign body, mucoviscidosis, tuberculosis, immune defects and an intrathoracic mass lesion must all be considered. The aim of treatment is to normalize pulmonary function and completely restore the child's physical robustness.

Administration, Inhalation↗
PubMed1993

Road traffic and adverse effects on respiratory health in children.

OBJECTIVES: To examine whether road traffic in a big city has a direct effect on pulmonary function and respiratory symptoms in children. DESIGN: Cross sectional study. SETTING: Of all 7445 fourth grade children (aged 9-11 years) in Munich, 6537 were examined. Of the children with German nationality and the same residence during the past five years and known exposure data, 4678 questionnaires and 4320 pulmonary function tests could be analysed. MAIN OUTCOME MEASURES: Variables of pulmonary function by forced expiration and respiratory symptoms reported in a questionnaire; census data on car traffic collected in the school district. RESULTS: Density of car traffic ranged from 7000 to 125,000 cars per 24 hours. Multiple regression analysis of peak expiratory flow showed a significant decrease of 0.71% (95% confidence interval 1.08% to 0.33%) per increase of 25,000 cars daily passing through the school district on the main road. Maximum expiratory flow when 25% vital capacity had been expired was decreased by 0.68% (1.11% to 0.25%). In contrast, response to cold air challenge was not increased. The adjusted odds ratio for the cumulative prevalence of recurrent wheezing with the same exposure was 1.08 (1.01 to 1.16). Cumulative prevalence of recurrent dyspnoea was increased, with an odds ratio of 1.10 (1.00 to 1.20). Lifetime prevalence of asthma (odds ratio 1.04; 0.89 to 1.21) and recurrent bronchitis (1.05; 0.98 to 1.12) were not significantly increased. CONCLUSIONS: High rates of road traffic diminish forced expiratory flow and increase respiratory symptoms in children.

Automobiles↗