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P Wagner

Publications and source records attributed to P Wagner.

At least 145 records · Page 8Linked to original sources
PubMed1990

A model for neuronal oscillations in the visual cortex. 2. Phase description of the feature dependent synchronization.

In a previous paper we have shown, that it is possible to model the oscillations observed in an orientation specific column in the visual cortex by coupling excitatory and inhibitory subpopulations of neurons which compose the column, and that these oscillations can be described by the phases of the corresponding limit cycle oscillators. By coupling different columns via long but finite range sparse interactions, we generate in the phase description stimulus dependent multiplicative couplings which explain experimentally observed synchronization effects.

Animals↗
PubMed1990

[Extracorporeal membrane oxygenation and CO2 elimination].

The mortality in patients with ARDS stage IV is 90% according to the classification of Morel (1985) since all experiments as treatment with prostaglandine antagonists and application of antioxidants have to improve the outcome of such patients, we treated 87 patients, aged 5-51 years, between 1985-1990, with a veno-venous extra-corporeal bypass for CO2-elimination and with low frequency positive pressure ventilation according to the method of Kolobow et al. Forty-six of 87 patients survived, i.e. the mortality was reduced to 47%. This is striking evidence that this method is superior to other treatments of patients with ARDS.

Adolescent↗
PubMed1989

[Pericardial tamponade following extraction of a pacemaker electrode].

A case of pericardial tamponade in a male patient secondary to the removal of an epicardial pacemaker wire is reported, resulting in rapid circulatory deterioration. Sternotomy with subsequent pericardectomy immediately relieved the compression of the heart. The postoperative period was complicated by a cerebral infarction on the third postoperative day, probably caused by cardiac embolism while the role of intraoperative hypotension is uncertain.

Aged↗
PubMed1988

Essential nonmedical perinatal services for multiple birth families.

Parents of multiples suffer unique stresses which can severely impair family health and welfare. Access to information, counseling, and community resources increase parents' abilities to cope, and reduce the risk of child and spousal abuse. Twinline, a social service agency in California, provides a variety of free and low-cost nonmedical perinatal services to meet the needs of a heterogeneous population of over 1,000 multiple birth families and parents expecting multiples in the urban and rural counties of the San Francisco Bay Area.

California↗
PubMed1988

Reexpression of poly(sialic acid) units of the neural cell adhesion molecule in Wilms tumor.

A unique structural feature of the neural cell adhesion molecule N-CAM is the presence of homopolymers of alpha (2----8)-linked sialic acid units. We have used two specific probes for the detection of poly(sialic acid) in normal human kidney and Wilms tumor: a monoclonal antibody against meningococci group B capsular polysaccharide (homopolymers of alpha (2----8)-linked sialic acid units), which shows no crossreactivity with polynucleotides and denaturated DNA, and bacteriophage-induced endosialidases specifically hydrolyzing alpha (2----8)-linked poly(sialic acid) units. Additionally, for the detection of N-CAM, antibodies recognizing the polypeptide portion of the molecule and biotinylated antisense RNA transcribed from a cDNA clone for N-CAM were applied. Poly(sialic acid) was regionally detectable in human embryonic kidney but undetectable in normal adult kidney, as already reported for rat kidney. The malignant Wilms tumor, which is characterized by the presence of structural components resembling those found in embryonic kidney, reexpressed poly(sialic acid) units and showed positive immunostaining for the polypeptide portion of N-CAM. Immunoblot analysis of Wilms tumor as well as human embryonic kidney and brain with the monoclonal anti-poly(sialic acid) antibody revealed in each case the same high molecular mass broad band. In situ hybridization demonstrated the presence of mRNA for N-CAM in Wilms tumor. We conclude that poly(sialic acid), most probably present on N-CAM, is an oncodevelopmental antigen in human kidney.

Antigens, Surface↗
PubMed1988

Presence of the long chain form of polysialic acid of the neural cell adhesion molecule in Wilms' tumor. Identification of a cell adhesion molecule as an oncodevelopmental antigen and implications for tumor histogenesis.

The long chain form of polysialic acid characteristic of the low adhesive embryonic form of the neural cell adhesion molecule NCAM is temporally and spatially expressed in developing kidney but undetectable in normal adult kidney. Therefore, this molecule represents a developmentally regulated antigen in kidney contrasted with neural tissue, where it is also detectable in the adult brain. This investigation of 25 Wilms' tumors comprising all different histologic types demonstrates expression of this molecule under conditions of malignant growth. Immunostaining was observed in Wilms' tumors with both a monoclonal anti-polysialic acid antibody and a polyclonal anti-NCAM polypeptide antiserum. Intense cell surface staining sensitive to endosialidases specifically hydrolyzing alpha 2,8 linked (poly)sialic acid was detectable in blastemal regions, and weaker, variable labeling was seen over tubules and glomeruloid bodies. The stroma was not stained. This is evidence indicating that Wilms' tumor originates from the embryonic equivalent of induced metanephrogenic mesenchyme. It seems unlikely however, that the stroma is derived from the blastema. The same high molecular mass broad band typical of the embryonic form of NCAM was revealed by immunoblot analysis of homogenates from Wilms' tumor as well as from embryonic kidney and brain. In situ hybridization demonstrated the presence of mRNA for NCAM in all but stromal elements of Wilm's tumors. Thus, polysialic acid is present on NCAM and represents a new oncodevelopmental antigen in human kidney. Polysialic acid was greatly reduced or absent by immunohistochemistry and immunoblotting in necrotic tumor areas.

Adult↗
PubMed1988

Occurrence and distribution of sialic acid residues in developing rat glomerulus: investigations with the Limax flavus and the wheat germ agglutinin.

Evidence has accumulated suggesting that cell surface sialic acid is required for the development and maintenance of the specialized shape of glomerular podocytes in kidney. We have investigated the occurrence and distribution of plasma membrane sialic acid residues during glomerulus development in newborn rat kidney with special attention to the differentiating podocytes. Terminal sialic acid residues were detected with a high resolution cytochemical lectin technique applying the Limax flavus agglutinin in conjunction with the fetuin-gold complex. In addition, the wheat germ agglutinin/ovomucoid-gold technique was performed. Lectin binding, indicative of the presence of terminal sialic acid residues in glycoconjugates, was found in the plasma membrane of the cells of the nephrogenic cap, the earliest stage of glomerulus development. Label of similar intensity was found in the apical, lateral and basal plasma membrane of all cell types in later developmental stages such as renal vesicle, S-shaped body, capillary loop stage and maturing glomeruli. Considering the podocytes, already the presumptive podocytes clearly identifiable in the S-shaped body and early capillary loop stage exhibited binding sites for the Limax flavus and the wheat germ agglutinin along their plasma membrane domains irrespective of the position of the tight junctions and before foot process and slit diaphragm formation occurred. These results demonstrate that in the plasma membrane of all cell types during the different stages of glomerulus development sialylated glycoconjugates are present. They indicate that the general occurrence of sialic acid residues does not coincide with the development of foot processes and slit diaphragms of glomerular podocytes.

Animals↗
PubMed1987

The ras-related ypt protein is an ubiquitous eukaryotic protein: isolation and sequence analysis of mouse cDNA clones highly homologous to the yeast YPT1 gene.

The YPT1 gene of the yeast Saccharomyces cerevisiae codes for a guanine nucleotide-binding protein which is essential for cell viability. Using as hybridization probe cloned yeast YPT1 gene sequences, we have isolated from cDNA libraries prepared from RNA of mouse F9 and C3H10T1/2 cells several overlapping cDNA clones with identical sequence in the regions of overlap. The cDNAs were derived from a gene, designated ypt1, which codes for a protein of 205 amino acids with 71% homology to the yeast YPT1 gene product. Amino acid sequences typical for guanine nucleotide-binding proteins and characteristic for ypt proteins are perfectly conserved in the mouse ypt1 protein. Two mRNAs of 1600 and 3200 nucleotides, originating from the mouse ypt1 gene and differing in the length of their 3'-non-translated region, were identified in mouse F9 cells and in all mouse tissues examined. A monoclonal antibody specifically recognizing the 23.5-kd yeast YPT1 protein cross-reacted with a protein of identical size on protein blots of mouse, rat, pig, bovine and human cell lines.

Amino Acid Sequence↗
PubMed1987

Biochemical properties of the ras-related YPT protein in yeast: a mutational analysis.

Using site-directed mutagenesis, the ras-related and essential yeast YPT1 gene was changed to generate proteins with amino acid exchanges within conserved regions. Bacterially produced wild-type proteins were used for biochemical studies in vitro and were found to have properties very similar to mammalian ras proteins. Gene replacement allowed the study of physiological consequences of the mutations in yeast cells. Lys21----Met and Asn121----Ile substitutions rendered the protein incapable of binding GTP and caused lethality. Ser17----Gly and Ala65----Thr substitutions slightly changed the protein's apparent binding capacity for either GDP or GTP and altered its intrinsic GTPase activity. These mutations were without effect on cellular growth. The YPTgly17,thr65 mutant protein displayed a significantly altered relative capacity for guanine nucleotide binding but a GTPase activity comparable to the wild-type protein. In contrast to the Ala65----Thr substitution, the double mutant displayed a significantly reduced capacity for autophosphorylation and allowed cells to grow only poorly. Cellular growth was improved when this mutant protein was overproduced.

Amino Acid Sequence↗
PubMed1987

[Local fibrinolytic therapy of vascular occlusions in the pelvic-leg area and the upper extremity].

Seventy-three patients with vascular occlusions in the pelvis or lower limbs and three patients with upper limb lesions were treated by local low dose fibrinolysin, with strict control of any possible bleeding tendencies. Adequate recanalisation was obtained in 56 patients (73.6%). In ten patients, the occlusion recurred while the patient was still in hospital. After four to six months, 37 of the 56 (67%) of the vessels were still patent. In 18 patients, peripheral emboli resulted in some deterioration, but in 15 of these cases this could be treated successfully by operation. The methods and indications of local fibrinolysis therapy and the problems associated with it are discussed.

Adult↗
PubMed1986

The ras-related YPT1 gene product in yeast: a GTP-binding protein that might be involved in microtubule organization.

The 23.5 kd protein product of the ras-related YPT1 gene of S. cerevisiae was found to be essential for cell growth. The loss of YPT1 function, studied in cells with the YPT1 gene on chromosome VI regulated by the galactose-inducible GAL10 promoter, led to arrested cells that were multibudded and exhibited a complete disorganization of microtubules and an apparent loss of nuclear integrity. The YPT protein binds GTP specifically. GTP binding of the protein is essential for its intracellular function. The Asn121----IIe substitution, generated by site-directed mutagenesis, had a dominant lethal phenotype, the expression of the mutant protein led to binucleated cells and abnormal spindles. In contrast to the S. cerevisiae RAS1 and RAS2 gene products, the YPT protein seems to be involved, directly or indirectly, in microtubule organization and function.

Actins↗
PubMed1986

[High-resolution 7.5-/10-MHz B-scan sonography for the localization of hyperparathyroid tumors].

Apart from computed tomography, sonography is the most valuable clinical method for the pre-operative diagnosis of parathyroid tumours. Eighty-six patients were examined by high resolution ultrasound (7.5 and 10 MHz) and in 63 of these the sonographic findings could be compared with the results of surgery. Sensitivity of 67.5% was highest amongst 40 patients with primary hyperparathyroidism. Patients who had had previous operations on the neck showed a slightly lower sensitivity of 65%. In secondary and tertiary hyperparathyroidism, sensitivity was 54%. The main causes of error were small size of the adenoma, changes in the thyroid gland and previous surgery to the neck. The value of sonography for diagnosis and surgical planning is discussed.

Adenoma↗
PubMed1985

[Computer tomography in partial optic nerve avulsion].

An partial avulsion of the optic nerve was found after a blunt ocular trauma in a 34-year old-patient. For the first time it is possible to demonstrate CT exposures of such a case. The importance of this method in cases of blunt ocular trauma accompanied by hemorrhages of the anterior chamber or the vitreous is discussed.

Adult↗