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Biomedical subjects

J Robert

Publications and source records attributed to J Robert.

At least 595 records · Page 33Linked to original sources
PubMedDate not supplied

Antitumor and antiproliferative effects of an aqueous extract from the marine diatom Haslea ostrearia (Simonsen) against solid tumors: lung carcinoma (NSCLC-N6), kidney carcinoma (E39) and melanoma (M96) cell lines.

An aqueous extract of the marine diatom Haslea ostrearia (Simonsen) was studied for its antiproliferative properties against human solid tumors: lung carcinoma (NSCLC-N6), kidney carcinoma (E39) and melanoma (M96). These types of carcinoma are particularly chemoresistant. The extract has a potent cytostatic effect in vitro on the three cell lines and blocks the NSCLC-N6 line in the G1/S phase of the cell cycle. Moreover, the extract strongly inhibits tumor growth of NSCLC-N6 bearing nude mice. These preliminary results indicate that the aqueous extract of Haslea ostrearia exhibits inhibitory effects both in vitro and in vivo against solid carcinoma lines, suggesting the presence of a new potent antitumor agent in the aqueous algal homogenate.

Animals↗
PubMedDate not supplied

High prevalence of antithyroid antibodies in anti-glomerular basement membrane antibody-mediated disease.

Anti-glomerular basement membrane antibody (anti-GBM Ab)-mediated disease and autoimmune thyroiditis are characterized by the presence of organ-specific antibodies. The diagnosis of autoimmune thyroiditis is usually based on the presence of serum antithyroid antibodies. Few studies have addressed the relationship between anti GBM-Ab mediated disease and autoimmune thyroid pathology. Given that this disorder is often asymptomatic, associations of the two pathologies may be under-diagnosed. This study investigated the prevalence of serum antithyroid antibodies (antithyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO)) in patients with anti-GBM Ab-mediated disease. Antithyroid antibodies presence was investigated in sera from 35 patients in whom anti-GBM Ab-mediated disease had been diagnosed. Anti-glomerular basement membrane antibodies and anti-thyroid antibodies (anti-TG and anti-TPO) were assayed using an enzyme-linked immunosorbent assay. Forty-five percent of patients with anti-GBM Ab-mediated disease (16/35) had positive antithyroid antibody titers. Eighteen percent (3/16) suffered from subclinical hypothyroidism. In conclusion, the high prevalence of antithyroid antibodies in these patients suggests a possible pathogenic link between autoimmune thyroiditis and anti GBM Ab-mediated disease.

Adult↗
PubMedDate not supplied

Detection of DNA-strand breaks in cells treated with F 11782, a catalytic inhibitor of topoisomerases I and II.

F 11782, or 2", 3"-bis pentafluorophenoxyacetyl-4',6'-ethylidene-beta-D glucoside of 4'-phosphate-4'-dimethylepipodophyllotoxin 2N-methyl glucamine salt, is a novel fluorinated lipophylic epipodophylloid which has proven cytotoxic activity in vitro and has shown markedly superior antitumour activity in vivo compared to etoposide in various experimental tumour models. However, the precise mechanism(s) of cytotoxicity of F 11782 remains to be defined. In this study, the DNA damaging activity of F 11782 was investigated in GCT27 and C6S cells using, respectively the fluorescence enhancement assay and the technique of DNA alkaline elution. All the results obtained were consistent with induction of DNA damage by F 11782. No evidence of any stabilisation of DNA-topoisomerase cleavable complexes though was obtained with this catalytic inhibitor. Furthermore, such induction of DNA damage has not been reported with other known catalytic topoisomerase inhibitors and so it appears to be unique to F 11782.

Animals↗
PubMedDate not supplied

Chromosomal modifications of a rat glioblastoma cell line during the acquisition and reversal of doxorubicin resistance.

We have studied the cytogenetic alterations occurring during the development and reversal of doxorubicin resistance in a clonal line of rat glioblastoma cells. We have observed during the acquisition of resistance an increase in the modal number of chromosomes, from 42 to 60, and the occurrence, in 90% of the mitoses, or large metacentric markers(s) which were infrequent in the sensitive line. This was associated with a net increase in total DNA amount per cell, from 5.3 to 8.3 pg. During reversal of resistance by 2 years culture without drug of the most resistant line, we observed a rapid decrease of the chromosome number as well as of the DNA content per cell; however, the large metacentric marker(s) were still present in 40% of the mitoses after 9 months of reversal, when the remaining resistance was only 4-fold. In situ hybridization of the chromosomes with a probe for the mdr gene revealed that the average number of stained chromosomes rose from 7% in the sensitive line to 38% in the most resistant line; however, only 9% of the silver grains were detected on the large metacentric markers. We conclude that important chromosome rearrangements occurred during the acquisition of resistance to doxorubicin, leading to a random distribution of the mdr gene in the genome.

Animals↗
PubMedDate not supplied

Antitumor activity of gallium and lanthanum: role of cation-cell membrane interaction.

Using the vital dye inclusion method and the radioisotopic study of Ca2+-transport, we have investigated the involvement of the gallium and lanthanum plasma-membrane interaction in the cytotoxic and antitumor characteristics of both cations. The experimental results support the hypothesis that such an interaction is the principal cause of antitumor activity, either through structural changes of the cell membrane or through inhibition of the ATPase pumps.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Non specific immunity of children with selective IgA deficiency. Aggravating role of abnormal phenotype of alpha-1-antitrypsin (author's transl)].

Among 998 children with recurrent respiratory diseases 26 children with selective IgA deficiency were found. Three groups were considered according to IgA level in serum: group I with IgA under 0.05 g per litre; group II with IgA between 0.05 and 0.3 g per litre; group III with IgA above 0.3 and under 1 g per litre. Non specific immunity was studied in these patients including immunoglobulin levels, alpha-1-antitrypsin (A.A.T.) phenotypes, phagocytosis of staphylococcus aureus by PMN, lysozyme level, complement system. Cellular immunity was evaluated by IDR tests and rosette forming cells (RE). Only non specific immune systems were disturbed in some patients and appeared as aggravating factors in IgA deficient patients. We found: Abnormal phenotypes of ATT in 11 cases; deficiencies of engulfment in 6 cases, of bactericidal activities of PMN in 7 cases out of 16 studied; decrease of lysozyme level in 4 cases out of 17 studied; increase of IgE level in 9 cases with atopic symptoms in 7 patients. In our experience the chief aggravating factor in IgA deficient patients is abnormal phenotype of AAT.

Adolescent↗