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Biomedical subjects

A Colson

Publications and source records attributed to A Colson.

8 recordsLinked to original sources
PubMed2003

Inhibition of TNF-alpha production by pentoxifylline does not prevent endotoxin-induced decrease in serum IGF-I.

Sepsis and endotoxin (LPS or lipopolysaccharide) injection induce a state of growth hormone (GH) resistance leading to decreased circulating insulin-like growth factor (IGF)-I. Because the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta inhibit the GH-stimulated IGF-I expression in vitro, it was tempting to speculate that these two cytokines might play an important role in the reduction of circulating IGF-I levels caused by LPS. Pentoxifylline, a methylxanthine usually used in the treatment of peripheral arterial circulatory disorders, has been reported to inhibit TNF-alpha synthesis. The goal of our study was to investigate whether inhibition of TNF-alpha production by pentoxifylline could prevent the decrease in IGF-I and the GH resistance caused by LPS injection. Because previous studies demonstrated that pentoxifylline can reduce muscle catabolism induced by sepsis, we also assessed whether pentoxifylline could exert its anticatabolic effect by preventing the decrease in circulating IGF-I. LPS injection in rats decreased serum IGF-I (-45% at 12 h; P<0.01 vs time 0) and its liver mRNA (-67% at 12 h; P<0.01 vs time 0) while it induced circulating TNF-alpha and IL-1beta and their hepatic expression (P<0.01). Pretreatment of LPS-treated animals by pentoxifylline abolished the LPS-induced rise in serum TNF-alpha (-98% at 90 min; P<0.001 vs LPS alone) and to a lesser extent in serum IL-1beta (-44% at 3 h; not significant vs LPS alone). Despite its dramatic inhibitory effect on TNF-alpha induction, however, pentoxifylline failed to suppress both the decrease in IGF-I and the GH resistance induced by LPS in rats. These results suggest that mediators other than TNF-alpha, in particular IL-1beta or IL-6, could contribute to the GH resistance induced by LPS. They also suggest that the anticatabolic effect of pentoxifylline is not due to prevention of the decline of circulating IGF-I.

Animals↗
PubMed2000

HIV-1 genotypic zidovudine drug resistance and the risk of maternal--infant transmission in the women and infants transmission study. The Women and Infants Transmission Study Group.

OBJECTIVES: Although the treatment of pregnant women and their infants with zidovudine (ZDV) has been remarkably effective in preventing the perinatal transmission of human HIV-1, many potentially preventable infections still occur. To examine whether the risk of perinatal infection is increased among women who carry ZDV-resistant HIV-1, the role of genotypic ZDV resistance in perinatal transmission was evaluated. METHODS: The reverse transcriptase (RT) region of clinical isolates from culture supernatants of 142 HIV-1-infected women enrolled in the Women and Infants Transmission Study (WITS), who had been treated with ZDV during pregnancy was sequenced. Results from genotypic sequencing were linked to demographic, laboratory, and obstetrical databases, and the magnitude of association of having consensus drug-resistant HIV-1 RT mutations with transmission was estimated. RESULTS: Twenty-five per cent (34/142) of maternal isolates had at least one ZDV-associated resistance mutation. A lower CD4 cell percentage and count (P= 0.0001) and higher plasma HIV-1 RNA (P=0.006) were associated with having any ZDV resistance mutation at delivery. Having any RT resistance mutation [odds ratio (OR): 5.16; 95% confidence interval (CI): 1.40, 18.97; P=0 0.01], duration of ruptured membranes [OR: 1.13 (1.02, 1.26) per 4 h duration; P= 0.02], and total lymphocyte count [OR: 1.06 (1.01, 1.10) per 50 cells higher level; P=0.009] were independently associated with transmission in multivariate analysis. CONCLUSION: Maternal ZDV resistant virus was predictive of transmission, independent of viral load, in these mothers with moderately advanced HIV-1 disease, many of whom had been treated with ZDV before pregnancy.

Anti-HIV Agents↗
PubMed2000

Potentiation of growth hormone-induced liver suppressors of cytokine signaling messenger ribonucleic acid by cytokines.

Endotoxin and proinflammatory cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNFalpha) induce a state of GH resistance. A new family of suppressors of cytokine signaling (SOCS), induced by cytokines activating the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, has been recently identified as a negative feedback loop of intracellular signaling. Overexpression of some SOCS (SOCS-3, CIS, and SOCS-2) has been reported to inhibit the JAK-STAT pathway stimulated by GH. To assess the possible role of these three SOCS proteins in the GH resistance induced by endotoxin and cytokines, we investigated the regulation of their gene expression by endotoxin and GH in rat liver and by proinflammatory cytokines and GH in primary culture hepatocytes. Both GH and lipopolysaccharide induced the three SOCS messenger RNAs (mRNAs) in vivo. In vitro, GH also increased the liver mRNAs encoding SOCS-2, SOCS-3, and CIS. Although IL-1/beta and TNFalpha alone induced only weakly the expression of SOCS-3 and CIS, these cytokines strongly potentiated the induction of these two SOCS by GH. In contrast, IL-6 alone markedly induced SOCS-3 mRNA, but did not potentiate the GH action on SOCS-3 and CIS mRNAs. The GH induction of SOCS-2 was not potentiated by any of these cytokines. Considering the ability of these SOCS to inhibit the JAK-STAT pathway induced by GH, these results suggest that the overexpression of SOCS-3 and CIS mRNAs induced by IL-1beta and TNFalpha or by endotoxin in vivo may play a role in the GH resistance induced by sepsis.

Animals↗
PubMed1999

[Epithelial-myoepithelial carcinoma of the salivary glands: report of a case].

Epithelial-myoepithelial carcinoma (E.M.C.) is a rare lowgrade salivary gland neoplasm that occurs in both major and minor salivary glands. It is characterized by tubular and solid growth pattern with a dual cell population including an inner layer of epithelial cells which are peripherically bounded by a layer of clear myoepithelial cells. This differentiation is confirmed by electron microscopic and immunohistochemical studies. The differential diagnosis included clear cell tumor of the salivary gland and metastatic renal carcinoma. The majority of these tumours arise in the parotid in women with a peak incidence from the 6th to the 8th decade. We report a case of parotidic E.M.C. in a 33 year old man.

Adult↗
PubMed1996

Recurrent annular erythema with purpura: a new variant of leucocytoclastic vasculitis responsive to dapsone.

Annular lesions are rarely reported in the clinical spectrum of leucocytoclastic vasculitis, except in the acute haemorrhagic oedema of the skin. We report three patients who suffered from an extraordinary recurrent annular dermatitis, for 4 years in one case and for decades in the other two. The eruption was characterized by purpuric lesions that had a centrifugal evolution, creating target- or polycyclic patches disseminated on the limbs and trunk. The patients' general condition remained excellent during the attacks. All lesions spontaneously disappeared within 2 weeks, but recurred monthly. In all three cases, the histological changes were consistent with leucocytoclastic vasculitis. One patient had ulcerative colitis and another had a benign immunoglobulin A (IgA) monoclonal gammopathy. These two patients showed a good response to dapsone therapy. This dermatosis probably represents a new and rare variant of leucocytoclastic vasculitis.

Dapsone↗
PubMed1989

Auditory evoked potentials during propofol anaesthesia in man.

The effects of propofol on auditory evoked potentials were studied in nine patients undergoing otorhinolaryngology surgery. After recording of basal evoked potentials patients received propofol 2 mg kg-1 over 2-3 min for induction of anaesthesia. Potentials were recorded every 10 min (T1, T2, T3). During T1, T2, T3, the infusion rates of propofol for maintenance of anaesthesia were respectively 7, 5 and 3 mg kg-1 h-1 consecutively. Middle latency component was affected markedly. Brainstem waves latencies I, III, V were increased significantly, while amplitude waves I, III, V remained constant.

Adult↗
PubMed1984

[Ocular lesions induced by saccharin and its pollutants in the rat fetus].

The authors analyze and compare the teratogenic effects produced on the embryo eyes of rats by Maumee saccharin, by non purified Remsem saccharin and several pollutants. The study has been made on 2708 embryos of rats whose mothers have received per os several pollutants at several rates; 16 diets have been studied. The histological lesions are described: the cataract, the retinal coloboma, the major microphthalmos, the anophthalmos, the presence of aberrant nervous fibers, the anarchic globes. The authors describe the retinal eversion phenomenon in the retinal coloboma as well as its repercussion on the ocular malformations (retinal dysplasia and colobomatous cyst of the orbit). The presence of aberrant nervous fibers inside the retinal coloboma could explain the cases of double papilla, which were observed in clinic. The major microphthalmia are frequent. The serious anophthalmia are explained by an early perturbation of the embryogenesis. The anarchic globes could be interpreted as a form of congenital cystic eye. Under the different pollutants of the saccharin, four of them are more toxic: it is the ortho-sulfobenzoic acid, the para-sulfobenzoic acid, the para-sulfamolybenzoic acid, the para-toluenesulfonamide which communicate the Remsen saccharin its teratogenic effect. On the other hand, the ortho-toluene sulfonamide is without any teratogenic effect. The authors conclude on the necessity of a large purity of the commercial saccharin.

Animals↗