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Biomedical subjects

I Földes

Publications and source records attributed to I Földes.

At least 19 recordsLinked to original sources
PubMed1992

Oxytocin stimulates translocation of protein kinase C and induces antiviral state in human amnion cells.

Association of protein kinase C (PKC) activity to the membrane fraction was observed in oxytocin treated human amnion cells (UAC). In addition, oxytocin was shown to induce an antiviral state and to inhibit multiplication of vesicular stomatitis virus (VSV) in UAC. These observations together with earlier findings indicate that activation of inositol phospholipid breakdown with a consecutive activation of PKC is a common signal transduction pathway in interferon action and hormonal stimulation.

Amnion↗
PubMed1992

Establishment of an MT4 cell line persistently producing infective HIV-1 particles.

Human T cell Lymphotropic Virus-I (HTLV-I) carrying human T cell line MT4 is highly sensitive to Human Immunodeficiency Virus-1 (HIV-1). After HIV-1 infection cell clusters characteristic of intact MT4 rapidly disintegrate, syncytia appear and the cells die. Surviving MT4 cells were subcultured following HIV-1 infection of high multiplicity. We succeeded to establish an MT4 cell line continuously producing infective HIV (MT4/HIV-1). The original and the HIV-1 infected MT4 cells were morphologically similar. The MT4/HIV-1 cells proved to be nearly 100% positive in indirect immunofluorescence assay using the serum of an HIV-1 antibody positive individual. OKT4 surface antigen could not be demonstrated on MT4/HIV-1 cells. On electron microscopic pictures typical and atypical virus particles could be seen near the surface of the cell membrane. The persistently produced virus particles were infective for H9 and MT4 cells. The antigenic structure of the virus produced by MT4 cells was similar to that produced by H9 cells.

CD4-Positive T-Lymphocytes↗
PubMed1979

Inhibition of cortisone action in mice by heparin.

A single dose of heparin applied in a depot-form (Freund's incomplete adjuvant or Ca-phosphate gel) inhibits the effects of intraperitoneally injected cortisone on the lymphoid organs (thymus and spleen), on the peritoneal and peripheral lymphoid cell count and serum gamma globulin level as well as on the liver glycogen deposition in mice. The same dose of heparin did not influence the action of hydrocortisone measured on the thymic and spleen involution and liver glycogen content. The route of cortisone administration seems to be critical, as heparin shows no or only minor effects when cortisone is applied subcutaneously; moreover, the action of cortisone per se is more marked by subcutaneous than by intraperitoneal administration. The results suggest the hypothesis that heparin inhibits cortisone-cortisol conversion and this inhibition is mediated by macrophages.

Animals↗
PubMed1978

Neoplastic response of turkey liver to MC29 leukosis virus.

Twelve to fourteen days after intravenous inoculation of MC29 virus (1 x 10(5)LD50) into 1-day-old turkeys, liver tumour developed in 100% of the infected animals and led to death of birds. The tumour proved to be hepatomas histologically and electron microscopically. Numerous C-type particles were detectable among the tumour cells, as well as budding from the cell membrane. C-type particles were also observed in the tumour-free liver tissue in the spaces between the cells, budding was not detectable. Large number of virus particles were found in spleen extracellularly and intracellular vacuoles. Kidney tumours did not develop, but a few extracellular virus particles were located in the tissue. The MC29 virus-induced primary liver tumour in the turkey seems to be a suitable model for the morphological study of the relationship between oncogenic viruses and eukaryotic cells.

Animals↗
PubMed1977

Analysis of thymidine kinase activity and glucocorticoid-binding capacity in the thymuses of healthy and tumor-bearing chickens.

Thymidine kinase activity in the lymphoid organs of healthy and tumor-bearing chickens was studied after hydrocortisone or dexamethasone treatment. Glucocorticoid hormones (10 mg/100 g body wt) administered twice in 48 hours resulted in an 80% decrease in thymidine kinase activity in the thymuses of healthy chickens, whereas birds with transplantable MC 29 chicken hepatoma failed to respond to the hormones. In the bursae of Fabricius of healthy or tumor-bearing chickens, thymidine kinase activity did not change considerably after administration of hydrocortisone or dexamethasone. The steroid-binding capacity in cellfree systems prepared from thymuses of tumor-bearing birds was significantly decreased. Thus the difference in steroid-binding capacity between thymuses of healthy and tumor-bearing chickens correlated well with, and could account for, the failure of hydrocortisone and dexamethasone to reduce the thymidine kinase level in tumor-bearing birds.

Animals↗
PubMed1977

Studies on antituberculotic action of some phenothiazine derivatives in vitro.

Five phenothiazine derivatives (chlorpromazine, levomepromazine, diethazine, promethazine and chlorpromazine) sulphoxyde were tested for antimycobacterial activity. The growth of Mycobacterium tuberculosis, M. bovis and M. butyricum was inhibited by chlorpromazine practically at identical concentrations. The minimum inhibitory concentrations for M. tuberculosis were: chlorpromazine and levomepromazine, 10 microgram/ml; diethazine and promethazine 20 microgram/ml, whilst chlorpromazine sulphoxyde was ineffective even at a concentration of 100 microgram/ml. Chlorpromazine and promethazine exerted a measurable bactericidal activity on M. tuberculosis at 50 microgram/ml; total destruction of the organism and loss of acid fastness in part of the cells were shown at 300 microgram/ml. Preliminary studies, in mouse experiments phenothiazine derivatives were ineffective.

Antipsychotic Agents↗
PubMed1976

Are mast cells involved in adjuvant action?

A variety of adjuvant substances have been found to reduce the absolute and relative number of peritoneal mast cells in mice. This observation is discussed in the light of literary data suggesting a potential role of mast cells in the regulation (modification) of the immune response.

Adjuvants, Immunologic↗
PubMed1975

Tyrosine aminotransferase induction in normal and tumor-bearing chickens.

Tyrosine aminotransferase (TAT) induction by glucagon and dexamethasone in the liver of tumor-bearing chickens was studied and compared with induction in healthy animals. The transplantable tumor was caused by inoculation of cells from a cell line induced by MC29 avian leukosis virus. TAT was hardly detectable in tumor tissue of control and dexamethasone-treated chickens, but it was induced by glucagon to levels which were significant although very low when compared to those in host liver or the liver of non-tumor-bearing controls after glucagon treatment. Dexamethasone failed to induce TAT in host liver at 8 A.M. while it significantly indiced TAT in the normal liver at the same time of the day. Similar failure of TAT induction was not detectable when glucagon was used instead of dexamethasone. Furthermore, it was found that diurnal variations in basal and dexamethasone or glucagon-induced TAT levels are considerably mitigated in host liver as compared to those observed in the liver of healthy animals. The possible reasons for these findings are discussed.

Animals↗
PubMed1975

Trace elements in tissues of normal and vitamin D2-treated rats.

Comparative spectroscopic investigations were performed on 22 trace elements regarding their presence and quantitative relations in cartilages (costal cartilage, intervertebral disc) and in soft tissues most exposed to metastatic calcification (aorta, kidney) of normal, vitamin D2-treated and rachitic rats. The results revealed differences in concentration and distribution of trace elements between soft tissues and cartilages on the one hand, and untreated controls and vitamin D-treated rats on the other. On vitamin D treatment an increase in the Cr, Fe and Cu contents was noted in the soft tissues, whereas in cartilages a higher Zn content was shown. It is suggested that these trace elements may play an important role in the mechanism of calcification, some acting as challengers, others as adjuvants or inhibitors.

Animals↗
PubMed1975

Examination with x-ray diffraction of cartilaginous tissues of rats of different ages with and without vitamin D treatment.

X-ray diffraction examinations were performed on different cartilages (epiphysis, joint, rib, nose-cartilage and discus intervertebralis) of 10 young and 10 old rats. Half of the animals served as untreated control, the other half was treated daily with 40,000 U of vitamin D3 through a gastric tube for 14 days. The examinations were performed partly with a Philips diffractometer and partly in a Guinier chamber, in order to determine the quantitative and qualitative crystallite size. The results obtained are as follows: 1. Cartilage crystallites, except those of the epiphysis, are more rough-grained in the old than in the young animals. 2. A difference was found between cartilages of the same age but of different types. In epiphysial cartilage thin crystals of medium length are formed while thick ones can be seen in discus intervertebralis, joint and rib cartilage. 3. According to the data obtained with the method of X-ray diffraction the crystals in epiphysial cartilage and discus intervertebralis will be lengthened upon the effect of vitamin D, while those in the rib and nose-cartilage shortened and bulkier. It can be imagined that cartilage and bone cells as well as basal substance have an influence on the morphological picture of calcium phosphate. Thus different forms of crystal are formed in cartilages of different functional activity.

Aging↗
PubMed1975

The effect of glucose-1 phosphate calcium on the epiphyseal cartilage of the rat.

Electron microscopic investigations were carried out on the proximal tibial epiphyseal cartilage of albino rats treated with 2 mg G-1-P-Ca daily for one and three weeks. The treatment--enhanced the secretory activity of the upper cells of the zone of maturing cartilage with a consequential enlargement of the Golgi region, depletion of secretory products, and an increase in the number of microtubuli. --In addition, the treatment increased the number of matrix vesicles in the extracellular space showing incipient calcification. This findings confirm the earlier light micriscopic observation of the calcification stimulating effect of G-1-P-Ca.

Animals↗
PubMed1975

Structure of the osteocyte capsule in rats with hypervitaminosis-D and rickets.

A histochemical and topo-optical study was made of the changes of the osteocyte capsule (OC) of the cortical and spongious bone layers of the tibia and vertebra of rats with hypervitaminosis-D and rickets. In hypervitaminosis-D the number of stained OCs was found to decrease. After treatment with high doses of vitamin D, a broadening of the OCs was noted in the area of demineralizing bone. Under the polarization microscope a decrease occurred in the proportion of birefringent OCs, more marked in birefringence than in staining. Since bone demineralization due to vitamin D was not followed by a rise in the number of osteoclasts, it is concluded that osteocytic activity has an important role in demineralization as shown by the broadened OC. In rachitic rats considerably fewer OC took the stain and showed birefringence than in the controls. Thus, alteration of the OC structure disturbs the nutrition of bone tissue and thereby aggravates the pathological process.

Animals↗