[Pathogenetic significance of IgE-binding epitopes allergens].
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Allergens↗
Biomedical subjects
G Schramm
Publications and source records attributed to G Schramm.
Major allergen Phl p Vb in timothy grass is a novel pollen RNase.
A cDNA coding for the major group V allergen Phl p Vb was isolated from a timothy grass pollen cDNA library by immunoscreening with a specific monoclonal antibody. It was discovered for the first time that the recombinant Phl p Vb pollen allergen after expression and purification has ribonuclease activity. High homology of Phl p Vb to other group V allergens in grass pollen indicates similar function. By RNase activity gel of natural pollen extract of timothy grass and consecutive Western blot analysis of the excised proteins, the RNase active bands were shown to be group V allergens. Additionally it was demonstrated that an homologous protein to Phl p Vb in the mother plant could be induced by salicylic acid. This indicates that group Vb allergens may be involved in host-pathogen interactions because in pollen they are quickly exported RNases and in the mother plant they depend on a hormone which is related to expression of plant resistance genes.
Allergens↗
Structural investigations of the major allergen Phl p I on the complementary DNA and protein level.
Until now investigations of group I grass allergens have mainly been performed on ryegrass allergen (Lol p I). We studied this major allergen grass group with timothy grass pollen (Phl p I), a very common and important cause of type I allergy, to determine intraspecific and interspecific variations among different grass species. By immunoscreening a timothy grass pollen complementary DNA library we obtained three full-length clones. They revealed identical nucleotide sequences in the coding regions consisting of 262 amino acids, including a leader sequence of 23 amino acid residues. The comparison of our data with the amino acid sequences deduced from Lol p I and Hol 1 I clones showed sequence identities of greater than 85% and homologies of greater than 90%, indicating a high degree of sequence conservation. Despite the high degree of homology, amino acid differences were in immunodominant positions, which may be responsible for the differing immune response to group I allergens of different grass species.
Allergens↗
Characterization of the allergen group VI in timothy grass pollen (Phl p 6). II. cDNA cloning of Phl p 6 and structural comparison to grass group V.
The complete primary structure of the major allergen Phl p 6 was determined by cDNA cloning. A cDNA library of timothy grass pollen was screened by a Phl p 6 directed mouse antiserum. Six clones were obtained. From the cDNA data we deduced a protein sequence of 110 amino acids. While the size of the leader sequences varied considerably between the different clones, only one amino acid exchange affected the mature proteins. Sequence comparison of group VI and V allergens showed a high degree of homology in the N- and C-terminal regions. The structural data strongly indicate that group VI and V are independent groups of allergens, which have derived from a common precursor gene.
Allergens↗
[Determination of the activities of lipase, lipoxygenase and peroxidase in native and extruded cereal brans].
To avoid fat deterioration in grain products during storage the cereal inherent enzymes lipase, lipoxygenase and peroxidase have to be inactivated. Known methods for the determination of the enzymes activity are tested and their applicability evaluated. Own optimized methods are presented. In laboratory and semiindustrial extrusion tests (laboratory single screw extruder, twin screw extruder, short screw extruder) the degree of enzyme inactivation of wheat bran, rye and maize bran, and oat bran is determined in dependence on the extrusion parameters. The enzymes mentioned already had been inactivated at mild extrusion conditions (temperature < 120 degrees C, moisture 20%, low mechanical stress). Only in brans of high fat content (10-14%) or high moisture (> 25%) minor residual activities of peroxidase and lipase were observed.
Dietary Fiber↗
Major allergen Phl p Va (timothy grass) bears at least two different IgE-reactive epitopes.
It is established that most grass pollen allergens consist of several isoforms of which the function is mainly still unknown. A number of these allergens belonging to group V have been cloned, sequenced, and expressed. Antigenic sites and IgE-reactive epitopes of the major allergen Phl p Va, are unknown. We have identified the complete cDNA sequence of a Phl p Va isoallergen by immunoscreening of a timothy grass pollen cDNA library and mixed oligonucleotide primed amplification of N-terminal cDNA. Additionally, we found an incomplete isoallergenic cDNA clone of the same protein. Immunoreactivity of the fusion proteins with patients' sera and monoclonal antibodies showed that the clones represent group Va allergens. Comparison of deduced amino acid sequences with published sequences of Lol p V and Poa p IX revealed a homology of 81.1% and 86.9%, respectively. With affinity-purified IgE antibodies recognizing the recombinant fusion protein, we can demonstrate the existence of a common group V IgE-reactive epitope. By construction of both an N-terminal and a C-terminal peptide of the complete Phl p Va and cross-inhibition, we identified at least two different IgE epitopes. Eleven patients showed variable IgE immunoreactivities to both IgE-reactive epitopes.
Allergens↗
Comparison of four grass pollen species concerning their allergens of grass group V by 2D immunoblotting and microsequencing.
The identification and characterization of allergenic components is a vital step towards improving diagnosis and therapy. Members of the grass family (Poaceae) reveal a high cross-reactivity among each other caused by the close phylogenetical relationship. In order to investigate the variability between allergenic components, we studied the allergen grass group V, one of the major allergens. Pollen extracts of 4 different tribes (timothy grass (Phleum pratense)--Agrostidae, perennial rye grass (Lolium perenne)--Festuceae, meadow velvet (Holcus lanatus)--Aveneae, and rye (Secale cereale)--Triticeae) of the Festucoideae subfamily were separated by 2D PAGE and investigated by immunoblotting using patients' poolserum and monoclonal antibodies (raised against group V allergens of timothy grass pollen). The antibodies identify different allergens in the four grass species. The components vary from 30-50 kDa and pI 4.8-7.0. The eight NH2-terminal amino acids were determined and indicated high similarities between the different components. These results cast doubt on the suitability of classifying allergens into groups based only on their molecular mass, isoelectric point and N-terminal sequence analysis. It suggests to classify allergens according to their IgE-reactive epitopes.
Allergens↗
The influence of nutritional factors on biopterin excretion in laboratory animals.
Nutritional influences on urinary total biopterin levels in rats and pigs were investigated. During the first nights in metabolic cages with food deprivation a significant increase in biopterin values was found in rats. This could be diminished either by feeding, adaptation to food deprivation or by oral glucose application. With food deprivation under normal housing conditions, this increase could not be found. Rats that were fed a cellulose preparation without metabolizable energy had no increase in biopterin excretion. The circadian rhythm of biopterin excretion was influenced by food deprivation as well as by cellulose. Alterations in water intake and urinary output had no effect on biopterin levels related to creatinine. Remarkable changes in biopterin excretion are more likely due to hormonal functions and regulations related to stress than to nutritional factors. More investigations into these problems are being performed.
Animal Nutritional Physiological Phenomena↗
[A Christmas letter by Dr. Alexander Tschirch, Bern, to his brother Dr. Otto Tschirch, Brandenburg on the Havel (1911)].
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Germany↗
[Developmental history of hospital pharmacy with special reference to public health].
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Europe↗
Local exchange of oxytocin from the ovarian vein to ovarian arteries in sheep.
Local transfer of 125I-labeled oxytocin from the ovarian vein to arteries supplying the ovary, the oviduct, and the tip of the uterine born has been investigated. In five sheep, 10 infusions of 125I-oxytocin over a period of 1 h were performed, and the concentration of labeled polypeptide in the peripheral plasma was compared to ovarian arterial plasma. During 2 consecutive infusions into each animal's ovarian vein, blood was collected simultaneously from the following sites: ovarian branch of the ovarian artery (OBOA), tubal branch of the ovarian artery (TBOA), uterine branch of the ovarian artery (UBOA), and from the jugular vein. In all experiments the concentration of 125I-oxytocin in ovarian arterial plasma was higher than in peripheral plasma. The ratio of ovarian artery/jugular vein for 125I-oxytocin was: OBOA 2.8, TBOA 1.8, UBOA 1.6. Based on a 4 ml/min blood flow through ovarian arteries supplying ovary, oviduct, and the tip of the uterine horn, the local transfer of the total amount of oxytocin infused was estimated to be about 1% (range: 0.1-4.4%). Analysis of variance did not reveal significant differences in the exchange ratios between OBOA, TBOA, and OBOA. However, the variances within these groups are significant, presumably because of anatomical variation in the degree of surface contact area between arteries and veins at the ovarian pedicle. It is concluded that polypeptides are locally recirculated to ovaries, oviduct, and the tip of the uterine horn in a higher concentration than is supplied by peripheral blood. This could provide a mechanism for local distribution and concentration of the ovarian peptides that regulate reproductive function.
Animals↗
Direct venous-arterial transfer of 125I-radiolabelled relaxin and tyrosine in the ovarian pedicle in sheep.
125I-labelled relaxin and tyrosine were infused into the ovarian vein to investigate transfer to branches of the ovarian artery at the ovarian pedicle in sheep. The ovarian arteries supply the ovary, the oviduct, and the tip of the uterine horn. An exchange of relaxin (n = 24) and tyrosine (n = 18) was observed in blood samples collected from all branches of ovarian arteries. This is expressed as a ratio of radioactivity greater than 1 between jugular venous blood plasma and arterial blood plasma. The average ratio (+/- s.d.) over the total infusion period of 1 h was 1.42 (+/- 0.35) for relaxin and 1.69 (+/- 0.38) for tyrosine with maximal values up to 4.9 and 2.9, respectively. Of the total amount of substance infused (348 pmol/h), 0.22% of the relaxin and 1.19% of the tyrosine reached the adjacent arteries directly. From these investigations it is concluded that molecules with a molecular weight of approximately 6000 can be transferred directly from veins to arteries at the ovarian pedicle, and the efficiency of this exchange does not only depend on molecular size.
Animals↗
[Morphology of articular cartilage during various functions].
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Animals↗
Corpus luteum regression induced by ultra-low pulses of prostaglandin F2 alpha.
In view of the pulsatile nature of PGF2 alpha secretion from the ovine uterus at the time of luteolysis, experiments were designed to examine the effect of pulsed infusions of PGF2 alpha on luteal function and to re-examine the minimal effective levels of PGF2 alpha required to induce luteolysis. To mimic physiological conditions, hour-long infusions of PGF2 alpha in increasing concentrations were given either 4 times in 19 h or 5 times in 25 h into the arterial supply of the autotransplanted ovary in conscious sheep on day 12 of an induced cycle. Blood flow and progesterone secretion rate from the ovary were used to monitor directly the luteolytic effect of administered PGF2 alpha. The concentration of LH in peripheral plasma was measured throughout each infusion experiment and the presence of a preovulatory peak of LH was used as an indicator of the permanence of luteal regression. Four pulses of PGF2 alpha in 19 h caused complete corpus luteum regression in only 1 of 4 animals whereas the addition of a fifth pulse (5 pulses in 25 h) caused permanent regression in 4 out of 4 animals. Infusion of 5 hour-long pulses of saline or PGF2 alpha at a rate less than 0.04 microgram/h did not induce permanent suppression of progesterone secretion. The average total effective dose of PGF2 alpha required to induce luteal regression when given as 5 pulses was 1/40th of the amount currently regarded as the minimal effective one when given by constant infusion into the ovarian artery. In another series of experiments the luteolytic effect of a single hour-long pulse of 0.1 microgram/h PGF2 alpha given daily for either 3 or 4 days was investigated. A significant fall (ANOVA, F0.01) in progesterone secretion rate, which reached a nadir at 5.3 +/- 2.2 h (means +/- S.D., n = 15), was followed by a recovery of progesterone secretion rate. Permanent luteal regression did not occur with this protracted regimen, suggesting that a relatively short pulse frequency of PGF2 alpha over a minimal period of 24 h is a necessary condition for physiological regression of the corpus luteum in sheep.
Animals↗
"Sleeve-rope closure" of the median sternotomy after open heart operations.
A new method of sternal osteosynthesis following median sternotomy using the "sleeve-rope" principle is introduced. This method has been successfully applied in 20 patients.
Cardiac Surgical Procedures↗
[Congenital aneurysms of the left atrium with intact pericardium--value of diagnostic methods for recognition, prognosis and therapy].
An intrapericardial aneurysm of the left atrial appendage in a 7-year-old girl is reported. Review of the 36 cases described up to now reveals that there is no specific age for this disease. It is therefore questioned whether this defect is really congenital in origin. Systemic embolism and serious rhythm disturbances are the most common complications; the younger the patient, the less likely they are to occur. Systemic embolism has only been described in the case of aneurysms located at the left atrial appendage, not in aneurysms of other parts of the left atrial wall. The risk of the development of rhythm disorders, however, is independent of the location within the left atrium. Clinical findings (including ECG) are nonspecific. Cardiomegaly and unusual configuration of the heart are constantly found, but are not pathognomonic. The diagnosis is usually confirmed by angiocardiography. Operation seems always to be indicated if complications are to be avoided. Operative deaths or complications during the follow-up after operation are not described. Nothing is known about the etiology of the disease.
Angiocardiography↗