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Biomedical subjects

I Sander

Publications and source records attributed to I Sander.

At least 37 records · Page 2Linked to original sources
PubMed1997

Identification of endogenous retroviral sequences based on modular organization: proviral structure at the SSAV1 locus.

The current genome sequencing projects reveal megabases of unknown genomic sequences. About 1% of these sequences can be expected to be of retroviral origin. These are often severely deleted or mutated. Therefore, identification of the retroviral origin of these sequences can be very difficult due to the absence of convincing overall sequence similarity. There are also many copies of solo-LTRs (long terminal repeats) distributed throughout genomic sequences. LTR and envelope sequences in general are among the most divergent parts of the retroviral genome and thus especially hard to detect in mutated endogenous sequences. We took advantage of the fact that these retroviral sections contain short highly conserved sequence regions providing retroviral hallmarks even after loss of overall similarity. We defined several sequence elements and peptide motifs within LTR and Env sequences and used these elements to construct models for LTRs and Env proteins of mammalian C-type retroviruses. We then used this strategy to identify successfully the hitherto missing LTRs and an env-like region in the S71 human retroviral sequence. Our approach provides a new strategy for identifying remotely related retroviral sequences in genomic DNA (especially human DNA), of potential significance for the interpretation of genomic sequences obtained from the current large-scale sequencing projects.

Amino Acid Sequence↗
PubMed1997

Differentiation between cosensitization and cross-reactivity in wheat flour and grass pollen-sensitized subjects.

BACKGROUND: To diagnose baker's asthma, occupational sensitization to wheat flour should be distinguished clearly from influences of cosensitization such as it may exist in pollinosis patients. To define the route of sensitization, the cross-reactivity between wheat flour and grass pollen allergens was investigated. METHODS: Two groups of atopic individuals with or without professional contact to wheat flour were screened by skin prick test for their sensitization to wheat flour and grass pollen and, in the case of hints for cosensitization, by Enzyme Allergo Sorbent Test (EAST). Cross-reactivity between wheat flour and grass pollen allergens was investigated by IgE binding inhibition assay using sera of 20 cosensitized individuals and by immunoblots. RESULTS: The immunological cross-inhibition between wheat flour and grass pollen proves some proteins to share common allergenic determinants. Significant differences between bakers and individuals not occupationally exposed to flour could be seen in the inhibition of IgE binding to wheat flour. While the IgE binding to wheat flour allergens was only slightly inhibited by grass pollen proteins in baker's sera its inhibition was nearly complete by this extract in sera of nonexposed atopics. Immunoblots indicate that wheat proteins with a molecular weight of about 8-12 and 22 kD preferentially react with sensitized bakers' IgE and not with IgE of other individuals. IgE binding to grass pollen allergens in immunoblots and inhibition experiments showed no differences between bakers and other subjects. CONCLUSION: In the group of atopics without professional contact to flour, the positive test results from wheat flour obviously ensue from contact to cross-reacting grass pollen proteins whereas bakers are exposed and sensitized to allergens of both sources. Such cross-inhibition experiments help to identify the source of sensitization which may be difficult to obtain in case of cross-reacting allergens.

Asthma↗
PubMed1996

Heating inactivates the enzymatic activity and partially inactivates the allergenic activity of Asp o 2.

BACKGROUND: Sensitization to various flours and flour additives in the baking industry has been known for some time. However, most studies refer to allergens in their native state. OBJECTIVE: The aim of our study was to find out how high temperatures during the baking process influence enzymatic and allergenic activities of the common flour additive alpha-amylase (Asp o 2), a relevant allergen for bakers derived from Aspergillus oryzae. METHODS: In order to assess the allergenicity of Asp o 2 during the baking process, four to 11 correspondingly sensitized bakers were investigated by Enzyme Allergo-Sorbent Test (EAST) with native Asp o 2 and Asp o 2 heated to 80, 90, 95, 99.8 or 200 degrees C. Furthermore, the enzymatic activity was assayed in simulated baking processes at the above mentioned temperatures. RESULTS: Elevated temperatures resulted in a gradual loss of IgE antibodies' recognition of Asp o 2 in two commercially available enzyme products. The enzymatic activity decreased more rapidly. Heating the enzyme to 200 degrees C abolished both the enzymatic and the allergenic activity of the enzyme. CONCLUSION: Based on these results, alpha-amylase in flour additives partially retains its allergenicity. This finding could be relevant for consumers.

Allergens↗
PubMed1996

[Evaluation of different broiler housing conditions on the basis of clinical, pathological, anatomical and laboratory diagnostic criteria--a summary].

In a cooperative study, the impact of different broiler housing conditions (see communication BUCHENAUER) on clinical, post-mortem and laboratory diagnostic (microbiological, parasitological, serological, immunological) parameters was investigated in the course of three different fattening period. Clinically, it was observed, that lower stocking densities allowed a relatively higher motility of the birds. On the other hand, necropsy findings, microbiological, parasitological, serological and immunological findings gave no indications that these parameters were influenced statistically significant by either one of the broiler keeping systems.

Animal Husbandry↗
PubMed1994

[Are amylases in bakery products and flour potential food allergens?].

The enzyme alpha-amylase from the mould Aspergillus oryzae (Asp o II) routinely used for the production of bread, cakes and pastries has in recent years been identified as an inhalative allergen for occupational diseases (bakers' asthma). It is doubtful whether this amylase in the final product, i.e. after the baking procedure, can still be regarded as an allergen. To clarify this question, detailed case histories on 138 subjects were recorded (98 allergics, 20 patients suffering form chronic intestinal diseases, 20 healthy controls). The clinical examinations included prick skin test and IgE antibody determination using one of the customary enzyme preparations. EAST showed a few of these 138 bread consumers to be weakly sensitized to the enzyme. One of the subjects displayed a significant reaction to alpha-amylase heated to 200 degrees C. As expected, eleven bakers sensitized to alpha-amylase by inhaling it in the workplace (positive prick test, positive case history) predominantly exhibited specific IgE antibodies to the native enzyme. Apart from one weakly positive finding, heated alpha-amylase yielded negative results in this collective. Baking conditions vary widely, especially with regard to single components, temperature and duration. Thus, further investigations as to residual allergenicity or the feasible occurrence of new antigenic determinants during the production of bread, cake and pastries are required. 27% of bakers examined and 9% of atopics showed antibodies to a flour inherent enzyme, a beta-amylase. On the whole, the selected conditions hinted at a weakly sensitizing potential inherent in baking flour and in added amylase.

Allergens↗
PubMed1994

Isolation and denomination of an important allergen in baking additives: alpha-amylase from Aspergillus oryzae (Asp o II).

The commercially available alpha-amylase from Aspergillus oryzae which is widely used as a baking additive was compared with a highly purified enzyme preparation. We used enzyme allergosorbent test (EAST), EAST inhibition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focussing, immunoblotting, and N-terminal amino acid sequencing to characterize the causative allergen. Our screening comprised 89 partially selected bakers. Forty-three (48%) of them had work-related respiratory symptoms; 14 (32%) of whom were sensitized to the baking additive. Significant immunological differences could not be found between crude and purified sample with the exception that the latter one produced nearly twice as high antibody values. Iodine starch staining demonstrated that the component which was exclusively or predominantly bound by IgE antibodies of symptomatic bakers represents the active alpha-amylase. According to the International Union of Immunological Societies (IUIS) nomenclature, the term Asp o II is suggested for this important occupational allergen.

Allergens↗
PubMed1993

[Ondine syndrome: presentation of pediatric aspects based on a case report].

The congenital central alveolar hypoventilation syndrome (Undine's syndrome, or Ondine's curse) is a rare disorder of central ventilation. In recent years a successful therapy has been found consisting of pacing of the diaphragm. Early diagnosis is therefore significant for preoperative management. In our paper, we present the clinical course of a female newborn with Ondine's curse. Conclusions for the further management by the paediatric staff are demonstrated.

Carbon Dioxide↗
PubMed1992

Sequence analysis of the catalytic subunit of H(+)-ATPase from porcine renal brush-border membranes.

The catalytic subunit of the H(+)-ATPase from brush-border membranes of porcine renal proximal tubules was labeled with the hydrophobic SH-group reagent 10-N-(bromoacetyl)amino-1-decyl-beta-glucopyranoside (BADG) which irreversibly inhibits proton pump activity in the absence but not in the presence of ATP. The labeled protein was purified and digested with proteinases. After isolation and sequencing of proteolytic peptides two BADG-labeled cysteines were identified. The amino acid sequences of the obtained proteolytic peptides were homologous to the catalytic subunit of V-ATPases. From mRNA of porcine kidney cortex a catalytic H(+)-ATPase subunit was cloned. 181 of the 183 amino acids which overlap in the sequence derived from the cDNA and the proteolytic peptides were identical, and the two deviations are due to single base exchanges. A comparison of the amino acid sequence derived from the cloned cDNA with sequences of catalytic H(+)-ATPase subunits communicated by other laboratories revealed 98%, 96% and 94% identity with sequences from bovine adrenal medulla, from bovine kidney medulla and from clathrin-coated vesicles of bovine brain. Between 64% and 69% identity was obtained with sequences from fungi and plants. The data show that the catalytic subunit of V-ATPases is highly conserved during evolution. They indicate organ and species specificity in mammalians.

Acetylglucosamine↗
PubMed1992

[The renal effects of dopamine therapy in premature infants in the first week of life].

It is known that Dopamine therapy induces loss of water and sodium on the first or second days of life. On the other hand, no studies have been published on renal function under long-term therapy. In our study we could prove an altered excretion of water and sodium as well as fractional sodium excretion in preterm infants who received dopamine for at least the first week of life. Conclusions for clinical practice are drawn.

Creatinine↗
PubMed1991

[Studies on the predictive value and prognostic significance of compliance measurements in artificially ventilated newborn infants].

In 29 mechanical ventilated preterm infants the compliance of the respiratory system (Crs) was determined. Newborn infants with severe respiratory distress syndrome show a decreased Crs. A significant correlation could be proved between the Crs and the pCO2 as well as the inspiratory pressure. The second estimation of the Crs after 48 hours refers to the prognosis of the ventilated newborn infants.

Humans↗
PubMed1991

[Prognostic predictive value of neonatal ultrasonic studies of the CNS and of EEG monitoring for the psychomotor development at 1 year of age].

The prognostic value of cranial ultrasound and EEG-monitoring for the developmental outcome at 1 year of age in 209 premature and full-term newborns was studied retrospectively. The first ultrasound examination was performed within the first three days of life. Further investigations were done depending on type of severity of the findings. The investigation was completed by EEG-monitoring in 41 patients. The infants were investigated for psychomotor development. 158 infants were found normally developed. Abnormal neonatal ultrasound findings were registered in 18.9% of them. Developmental retardation was observed in 46 infants. 54.3% of them had abnormal ultrasound findings. 2/3 of infants with neonatal major brain insults like IVH III-IV or leukomalacia showed serious neurological handicaps, whereas subependymal bleedings seem to be without influence onto the development. In contrast pathologic EEG's were of higher prognostic value. None of the infants with a abnormal EEG was developed normally.

Brain Diseases↗
PubMed1986

[Fetal tachycardia--a cause of nonimmunologic hydrops].

A case of nonimmune hydrops fetalis is demonstrated. The cause of this disorder was a severe fetal tachycardia. Prenatal findings, obstetric management, and neonatal outcome are described. Our data have been discussed with reference to the literature.

Adult↗