Influence of the Notch system in the therapeutic response of American tegumentary leishmaniasis.

BACKGROUND: The evolution and therapeutic outcome of American tegumentary leishmaniasis (ATL) depend upon many factors, including the balance between Th1 and Th2 cytokines to control parasite multiplication and lesion extension. Other cytokines known for their role in inflammatory processes such as interleukin IL-17 or IL-18 as well as factors controlling keratinocyte differentiation and the inflammatory process in the skin, like the Notch system, could also be involved in the disease outcome. Notch receptors are a group of transmembrane proteins that regulate cell fate decisions during development and adulthood in many tissues, including keratinocyte differentiation and T-cell lineage commitment, depending on their activation by specific groups of ligands (Delta-like or Jagged). OBJECTIVES: To compare the in situ expression of Notch system proteins (receptors, ligands and transcriptional factors) and cytokines possibly involved in the disease outcome (IL-17, IL-18, IL-23 and transforming growth factor-ß) in ATL cutaneous and mucosal lesions, according to the response to therapy with N-methyl glucamine. METHODS: Cutaneous and mucosal biopsies obtained from patients prior to therapy with N-methyl glucamine were analysed by immunohistochemistry and real-time polymerase chain reaction. RESULTS: Notch receptors and Delta-like ligands were found increased in patients with ATL, particularly those with poor response to therapy or with mucosal lesions. CONCLUSIONS: The increase of Notch receptors and Delta-like ligands in patients with a poor response to treatment suggests that these patients would require a more aggressive therapeutic approach or at least a more thorough and rigorous follow-up.

Anomalous expression of P-glycoprotein in highly drug-resistant human KB cells.

KB-A1 and KB-A10 are 2 multi-drug-resistant cell lines which are 100- and 1,000-fold resistant to Adriamycin, respectively. We have examined the expression of P-glycoprotein at the molecular and cellular levels in these human carcinoma cells. Both MDR cell lines, when compared to the parental KB-3-1, show characteristic increases in mdr 1 gene copy number, an increase in mdr 1 mRNA expression, a corresponding increase in transcription rate and a consequent over-expression of P-glycoprotein. However, the more highly resistant KB-A10 cells have a lower gene copy number, express less mdr 1 mRNA and contain less P-glycoprotein than the A1 cell line. To determine whether higher levels of cellular resistance were attributable to enhanced efficacy of P-glycoprotein or to other cellular regulatory mechanisms, we examined other major cellular properties known to be associated with the mdr phenotype. Both the KB-A1 and KB-A10 lines exhibit similar increases in protein kinase C activity as compared to the drug-sensitive parent. In addition, neither glutathione-S-transferase nor topoisomerase II activities account for enhanced resistance of the KB-A10 cells. The above observations are contrary to the premise that the level of drug resistance is necessarily proportional to expression of P-glycoprotein or to other common factors thought to participate in drug insensitivity; consequently, new mechanisms of resistance must be in operation in these cells.

Ontogenetic expression of the murine erythrocyte glycophorins.

The major sialoglycoproteins or glycophorins of the murine erythrocyte membrane, gp2 (Mr 44,000) and gp3 (Mr 29,000), are expressed as identical or closely related antigens by the three erythroid cell lines that succeed each other in normal mouse development. The embryonic forms of gp2 and gp3 differ from the adult forms by their mobility on SDS-PAGE. The apparent Mr values are increased by 1000-2000 for gp2 and 500 for gp3. An increase in the microheterogeneity of both embryonic and fetal forms of gp2 is also detected. Variations in glycosylation account in part for the apparent differences in Mr. Sizing of O-glycosidically linked oligosaccharide chains reveals that fetal glycophorins contain predominantly trisaccharide units while their adult counterparts are mostly tetrasaccharides. The kinetics of gp2 and gp3 biosynthesis in fetal liver are comparable to those established for the splenic erythroblasts of adult anemic mice. Like their adult counterparts, fetal glycophorins incorporate [3H]palmitate and [3H]galactose. The results indicate that, in murine ontogeny, distinct but antigenically related sialoglycoproteins are produced at each erythropoietic stage.

[Bad habits and dysgnathia: epidemiological study]. / Abitudini viziate e disgnazie: indagine epidemiologica.

The authors refer about an epidemiological survey in 651 children in the school-age. The aim of study is to investigate about the frequency of the bad habits and the pathogenetic relations between these and the development of the dento-maxillo-facial deformities. They point out an incidence of these bad habits in the 35,48% with a predominance of mouth breathers (45,45%). After they discuss the necessity of an early detection of anomalous neuromuscular attitudes.

Glycophorin expression in murine erythroleukaemia cells.

We have identified mature and putative precursor forms of glycophorins expressed in a virus-transformed murine erythroleukaemia (MEL) cell line and compared them with their normal erythroblast counterparts. The following differences were found: (1) the two major MEL cell glycophorins (apparent Mr values 29-30 and 43(x10(3] have greater mobility on polyacrylamide gels than their normal gp-3 and gp-2 counterparts, due at least in part to differences in their oligosaccharide sidechains; (2) MEL cell gp-3 consists of two discrete proteins; and (3) there are more potential glycophorin precursors in MEL cells than in normal mouse erythroblasts. Four proteins, with apparent Mr values of 21, 23, 26 and 27(x10(3], have tentatively been identified as glycophorin precursors, based on the following findings: (1) they are immunologically related to the glycophorins; and (2) their synthesis was induced by dimethyl sulphoxide coincidentally with that of gp-3 and gp-2. They do not appear to be glycoproteins, as evidenced by their lack of incorporation of [3H]galactose, [3H]glucosamine or [3H]mannose. In contrast, gp-3 and gp-2 incorporated [3H]galactose and [3H]glucosamine but not [3H]mannose. Partial characterization of the glycan moieties of MEL cell glycophorins indicates that they consist mostly of tri- and tetrasaccharides, with no indication of any N-linked chains. Hence, the glycans of MEL cell glycophorins are mostly (if not all) O-linked. Furthermore, treatment with N-glycanase did not change their electrophoretic mobility on polyacrylamide gels. MEL cell glycophorins were also shown to be modified by phosphoryl and fatty acyl groups.

The biosynthesis and fatty acid acylation of the murine erythrocyte sialoglycoproteins.

The biosynthesis and post-translocational processing of the murine erythrocyte sialoglycoproteins gp2 and gp3 have been studied on splenic erythroblasts obtained from mice rendered anemic by treatment with phenylhydrazine. A putative precursor-product relationship has been established between gp3 and a peptide (gp3pr) of apparent Mr = 22,000. No precursor to gp2 has been found. gp3pr was selectively and efficiently converted to gp3 in pulse-chase experiments after a 45-60-min chase. [3H]Palmitate labeled a series of splenic cell proteins, including gp2, gp3, and gp3pr. Chemical analyses indicated that the fatty acid is covalently linked to protein by an ester bond. Splenic cells incorporated [3H]galactose in both gp2 and gp3 but not in gp3pr. The results indicate that the murine sialoglycoproteins are modified in succession by fatty acid acylation and terminal glycosylation. [3H]Palmitate labeling appears to be an early modification that affects concomitantly gp3pr and gp3, suggesting that fatty acid acylation is a cytosolic event not obligatorily coupled to translocation.