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G Peters

Publications and source records attributed to G Peters.

At least 235 records · Page 13Linked to original sources
PubMed1988

Expression of the FGF-related proto-oncogene int-2 during gastrulation and neurulation in the mouse.

The proto-oncogene int-2 has been implicated in the formation of mouse mammary-tumour-virus-induced mammary tumours. Analysis of the predicted coding sequence indicates that int-2 is a member of the fibroblast growth factor family. Previous studies using Northern blot analysis suggested that normal expression of int-2 may be confined to extra-embryonic endoderm lineages of embryonic stages of mouse development. We have used in situ hybridization and Northern blot analysis to examine directly int-2 expression in embryo stem cells and in the developing embryo from early gastrulation to midsomite stages. Complex patterns of accumulation of int-2 RNA were observed in embryonic and extra-embryonic tissues. The data suggest multiple roles for int-2 in development which may include migration of early mesoderm cells and induction of the otocyst.

Animals↗
PubMed1988

Multiple RNAs expressed from the int-2 gene in mouse embryonal carcinoma cell lines encode a protein with homology to fibroblast growth factors.

Mouse embryonal carcinoma cell lines that differ in their patterns of expression of the potential oncogene int-2 have been exploited in a structural analysis of the multiple RNA transcripts characteristic of this gene. Ribonuclease protection experiments indicate that four major classes of int-2 RNA initiate at heterogeneous cap sites within two distinct promoter regions, P1 and P2, spanning approximately 50 and 150 bp respectively. The more downstream promoter P2 is located in a region of the DNA that constitutes an intron in RNA transcripts that initiate at the upstream promoter P1. Otherwise, all four RNA structures share the same splice donor and acceptor sites that define the boundaries of the second and third exons. Further complexity arises through usage of two distinct polyadenylation signals, both variants of the normal consensus, that are separated by 1100 bp. Despite these structural variations, the results suggest that all four major classes of RNA encode the same protein product which shows significant homology to the family of heparin-binding proteins typified by basic fibroblast growth factor (FGF).

Animals↗
PubMed1988

The role of capsule as a barrier to bacteriophage adsorption in an encapsulated Staphylococcus simulans strain.

The polyvalent staphylococcal bacteriophage U16 failed to adsorb to an encapsulated Staphylococcus simulans strain. Partially purified cell wall and teichoic acid of this strain could, however, inactivate bacteriophage U16 to a great extent, indicating the presence of the phage receptor. It is concluded that the capsule of Staphylococcus simulans acts as a barrier for the interaction of the phage with its receptor in the bacterial cell wall.

Abscess↗
PubMed1988

Typing of coagulase-negative staphylococci isolated from foreign body infections.

Twenty-six coagulase-negative staphylococci isolated from patients with various foreign body infections were characterised using different typing systems. Staphylococcus epidermidis was the most predominant species found. Phage typability was below 50% in all strains. The strains showed differences in surface properties--relative hydrophobicity or hydrophilicity--and ability to adhere to polystyrene with subsequent slime production (adherence tube test). Protein and polypeptide profiles as well as plasmid profiles demonstrated the heterogeneity of the strains. Thus, this preliminary study indicates that all coagulase-negative staphylococci of human origin may become involved in foreign body infections.

Bacterial Adhesion↗
PubMed1988

Suppression of natural cytotoxic cell activity by social aggressiveness in Tilapia.

Our earlier observations revealed that social stress causes drastic effects on different physiological mechanisms and degenerative changes in leucocytes. In this preliminary work, we analyzed the effect of social aggressiveness on functional activities of leucocytes emphasizing (NCC) activity in Tilapia. At 10 hr post stress induction, fish could be differentiated into three categories: 1) dominants; 2) subordinates; and 3) indeterminants. Results of NCC as indicated by 4 hr. 51Cr-release assay, demonstrated a significant suppression in cytotoxic reactivity in the subordinates and indeterminants compared to dominants. This suppression appears to be due to a decrease in the binding capacity of effector cells to YAC-1 target cells as indicated by the decreased number of conjugate forming cells. This binding process is a key event in activating the fish equivalent of NK cells in mammals. Decreased NCC-activity in stressed fish suggests that aberrations in cell mediated immunity result from social aggressiveness.

Aggression↗
PubMed1988

Hemagglutination by Staphylococcus saprophyticus and other coagulase-negative staphylococci.

Hemagglutination tests were performed to specify surface lectins (hemagglutinins) of four coagulase-negative staphylococcal species: S. saprophyticus (31 strains), S. epidermidis (5 strains), S. haemolyticus (3 strains), and S. warneri (3 strains). All strains of S. saprophyticus agglutinated sheep red blood cells (RBC) and the hemagglutination was inhibited by N-acetylglucosamine (GlcNAc) plus either N-acetylgalactosamine (GalNAc, 15 strains) or N-acetylneuraminic acid (NANA, 16 strains). Those strains showing inhibition by GalNAc also agglutinated horse RBC while those inhibited by NANA agglutinated rabbit RBC. The former type was more common among urinary tract isolates (10/15) and the second one among respiratory isolates (9/14). The eleven strains of other staphylococci agglutinated rabbit (and not sheep or horse) RBC; this hemagglutination was never inhibited by GlcNAc but instead by NANA alone or together with another sugar (7 strains) or by other sugars (4 strains, 3 different patterns of inhibition).

Animals↗
PubMed1988

Lectin-mediated cell-attachment and phagocytosis of Staphylococcus saprophyticus strain S1.

Adhesion studies with cryotome sections of human kidney and lung respectively uroepithelial cells together with blocking experiments with competitive carbohydrates suggested that specific attachment of S. saprophyticus strain S 1 to host cells apparently is mediated by lectins. Accordingly, microbial lectin blocking with specific glycoconjugates or lectin dysfunction (after treatment of bacteria with subinhibitory concentrations of tunicamycin) significantly decreased staphylococcal adherence to epithelial cells. Chemiluminescence measurements of human polymorphonuclear leukocyte (PMN) function yielded results suggesting importance of lectin-receptor interaction in phagocytosis, too, since PMN activity was significantly decreased after staphylococcal lectin blocking or dysfunction.

Bacterial Adhesion↗
PubMed1988

Fibronectin, fibrinogen, and laminin act as mediators of adherence of clinical staphylococcal isolates to foreign material.

Bacterial adherence to polymer surfaces is a required early step in intravenous (iv) device infection. We collected eight strains of Staphylococcus aureus and 19 of coagulase-negative staphylococci from patients with proven iv device bacteremia and studied the role of plasma or connective-tissue proteins in promoting bacterial adherence to polymethylmethacrylate (PMMA) coverslips. Although only a negligible percentage of organisms adhered to albumin-coated PMMA, surface-bound fibronectin significantly promoted adherence of all isolates. Fibrinogen markedly promoted adherence of all S. aureus strains but of only four coagulase-negative strains. Thus, coagulase-negative staphylococci revealed a marked heterogeneity in adherence to fibrinogen-coated surfaces, a result suggesting the existence of heretofore unknown receptors for fibrinogen. Laminin promoted adherence of staphylococci to a much lower extent. Although strain specific, adherence of clinical staphylococcal isolates to foreign surfaces is significantly increased by fibronectin, fibrinogen, and laminin, an observation suggesting the possible contribution of these proteins to the pathogenesis of iv device infection.

Bacterial Adhesion↗
PubMed1988

New considerations in the pathogenesis of coagulase-negative staphylococcal foreign body infections.

Coagulase-negative staphylococci are the predominant cause of foreign body infections. The pathogenesis is related to the ability of these staphylococci to adhere to and grow on polymer surfaces and to produce an extracellular slime substance. The exact chemical nature of this extracellular slime substance is still not known, although there is some evidence that it may be a complex glycoconjugate. On the basis of in-vitro and animal data, the extracellular slime substance seems to interfere with various host-protective mechanisms and with the action of antistaphylococcal antibiotics. These factors can explain several clinical characteristics of coagulase-negative staphylococcal foreign body infections.

Bacterial Adhesion↗
PubMed1988

Mechanisms and clinical relevance of bacterial adhesion to polymers.

The mechanisms of bacterial adhesion to polymers with regard to their significance in the development of foreign-body infections are discussed. The morphological, physico-chemical and biological aspects are treated with special emphasis on the adhesion of coagulase-negative staphylococci to medical polymers. Strategies for the prevention of bacterial adhesion to biomaterials by developing antiadhesive polymers are given.

Anti-Bacterial Agents↗
PubMed1988

Somatosensory and brainstem auditory evoked potential studies in nontraumatic coma.

We believe that somatosensory and brainstem auditory evoked response studies help in the understanding of the dysfunction of the ascending sensory pathyways at various levels. In some patients where EEGs showed a significant contamination of muscle and background noise, the SEP studies helped to identify the level of dysfunction. The severity of the clinical condition (GCS score) correlated significantly (p = 0.003) with the prolongation of the CCT. Asymmetries in CCTs were more frequent in the stroke group than in the other groups. The presence of asymmetries in CCT in diffuse encephalopathies indicated a variable degree of dysfunction in the ascending sensory pathways, which clinically were not easily identifiable. This fact raised the possibility of either pre-existing lesion(s) or recent insult(s) such as ischemia. The presence or absence of N20 appeared to influence the duration of survival in subgroups. Some degree of difference in duration of survival was noted among the metabolic group with and without N20 potential. The subset of patients with N20 potential survived relatively longer than the group without it. A suggestion of influence was seen in the stroke group, but caution must be exercised because the absence of N20 was compatible with survival. The hypoxic group did not show any difference. A combination of prolonged interpeak EP-N13 and N13-N20 indicated a poor prognosis. A distinct absence of Wave I in BAER limited its usefulness on some occasions. A combination of abnormal interpeak III-V and abnormal CCT seemed to suggest a poor prognosis. Although death generally occurred earlier in the stroke group, age did not seem to influence the mortality in the first 10 days. Similarly, the cause of death also did not seem to influence the course in those 10 days. None of the adult patients survived.

Adult↗
PubMed1988

Amplification of the int-2 gene in primary human breast tumors.

Proviral activation of the int-2 gene is a frequent occurrence in mammary carcinomas induced by mouse mammary tumor virus (MMTV). Here, we have examined the human homolog of int-2 in 110 primary breast cancer DNAs. The locus was amplified 2- to 15-fold in 18 of the tumor DNA samples. Amplification of int-2 has a highly significant association (P less than 2 X 10(-6] with tumors from patients who subsequently developed a local recurrence of the disease or a distal metastasis.

Animals↗
PubMed1988

[Relationships between structure and activity of anthracycline antibiotics of the rhodomycin group: inhibition kinetics of DNA and RNA viruses of the double- and single-strand types].

Antiviral activity from anthracycline antibiotics of rhodomycin-type was investigated by two independent methods, which determined the infectious units and antigenity of incomplete virions. The action of rhodomycin was dependent on structure, number and position of amino sugar, which is in aglycon. The viruses of double-stranded DNA and RNA viruses was stronger inhibited as single-stranded RNA viruses. The antiviral activity were found to increase in the serial order iremycin less than adriamycin less than daunomycin less than alpha-rubicin I less than beta-rhodomycin I less than violamycin BI-complex by inhibition kinetic determined from Adeno virus.

Anthracyclines↗