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Biomedical subjects

A Joss

Publications and source records attributed to A Joss.

At least 55 records · Page 3Linked to original sources
PubMed1969

Ribonucleic Acid and protein synthesis in chick embryo cells infected with fowl plague virus.

Fowl plague virus comprised four major protein components and several minor ones, two strains of the virus giving similar results. One of the components was identified as the nucleocapsid protein. Synthesis of the virion proteins could readily be detected in infected cells 3 hr after infection. The two subcellular fractions associated with viral ribonucleic acid (RNA) polymerase activity (nuclei and ribosomal pellet) were associated with the protein of the nucleocapsid and a second virion protein of unidentified function. Measurement of viral RNA and protein synthesis in cells infected with preparations of ultraviolet irradiated virus showed that the capacity to synthesise the RNA and protein species of highest molecular weight was lost most quickly, suggesting that the pieces of viral RNA function independently.

Journal Article↗
PubMedDate not supplied

In vivo early human dental plaque formation on different supporting substances. A scanning electron microscopic and bacteriological study.

Different studies have shown that various substances may have an influence on early human dental plaque formation. The purpose of the present study was to compare on tooth substances and supporting prosthetic materials the amount of plaque deposition by SEM and the quantity of selected bacteria using anaerobic culturing techniques. 5 bridges, replacing a missing molar or premolar, were incorporated in 3 patients. In the midbuccal area of each pontic, a semi-precision attachment was placed allowing the insertion of the following test facings: enamel, dentine, non gamma 2-amalgam, alloys of 85% and 55% gold, silver-palladium, chrome-cobalt, chrome-cobalt-titanium, and ceramic. For each material, 2 facings were fabricated. After 4 and 24 hours in situ, bacteriological samples were taken and processed for further identification. After a 2nd period of 4 and 24 hours in situ, the same facings were carefully removed and prepared for SEM-examination. All 4-hour specimens exhibited various areas covered by plaque, the amount of which varied with the different supporting substances. The very smooth surfaces (e.g., gold) harbored sparse deposits, while the rougher (e.g., amalgam) were covered by more plaque. After 24 hours of plaque development, an increase in the number of micro-organisms was noted for all the specimens. After 4 and 24 hours of plaque accumulation, no specific trends suggesting a preferential colonization on the different substances were observed. This study has shown that the amount of early deposits on different substances seems to be related to the degree of their surface roughness, while plaque formation was qualitatively similar.

Adult↗
PubMedDate not supplied

Mechanism of IL-10-induced T cell inactivation in allergic inflammation and normal response to allergens.

BACKGROUND: Induction of specific unresponsiveness (tolerance/anergy) in peripheral T cells and recovery by cytokines from the tissue microenvironment represent two key steps in specific immunotherapy (SIT) with whole allergen or antigenic T cell peptides. METHODS: Antigen-specific T cell responses and molecular mechanisms of T cell inactivation were investigated during conventional SIT, T cell epitope peptide immunotherapy and natural exposure to bee venom in allergic and hyperimmune individuals. RESULTS: T cell unresponsiveness, initiated by autocrine action of IL-10, is characterized by suppressed proliferative and cytokine responses. The unresponsive T cells can be reactivated by different cytokines that may mimic the microenvironmental cytokine influence. IL-10 initiates peripheral tolerance by blocking the CD28 costimulatory signal in T cells. Coprecipitation experiments reveal that upon stimulation CD28 and IL-10 receptor are physically associated in T cells. Accordingly, IL-10 binding to its receptor inhibits CD28 tyrosine phosphorylation, the initial step of the CD28 signaling pathway. This leads to inhibition of phosphatidylinositol 3-kinase p85 binding to CD28. IL-10 only affects T cells that receive a stimulation with low numbers of triggered T cell receptors and that require costimulatory signals by CD28. CONCLUSION: These data demonstrate the pivotal role of autocrine IL-10 and the interaction of its receptor with CD28 in the induction of T cell tolerance as an immunoregulatory mechanism controlling antigen-specific T cell responses.

Allergens↗
PubMedDate not supplied

[Indications for surgical treatment of abdominal aortic aneurysms].

The results of the surgical treatment of 115 patients with the abdominal aortal aneurysms are presented. Indications to surgery depending on the stage of aneurysm, way of classification, and coexisting cardiological disorders have been discussed. Excellent and favorable results of surgery have been achieved in 70 patients (60.9%). Overall hospital mortality rate was 39.1%. Out of patients who underwent elective surgery 11.6% died, in the group operated urgently--43.3%, and in emergency situation 89.4% of the operated patients died. Percentage of patients with coexisting cardiological disorders amounted to 54%, 62%, and 80% respectively. A strict correlation of the results of surgery and duration of the disease, and consequently classification to the treatment, has been noted. Indications to the elective surgery are related to the size of aneurysm, rate of its enlargement, patient's age, and general health.

Aged↗