Biomedical subjects

M Kraemer

Publications and source records attributed to M Kraemer.

94 records · Page 6Linked to original sources

PubMedDate not supplied

Dichotic listening and the cerebral organization of the phonetic and semantic components of language.

Two words were presented dichoticly and the subject was required to point to visually presented words that either rhymed with or were semantically related to those words. Task demands were varied in terms of the number and type of stimuli which the auditory and visual words actually matched. Performance was superior when either type of stimulus was presented to the Left Hemisphere via the Right Ear, resulting in the standard Right Ear Advantage (REA) for verbal material. The strength of the REA, however, depended both on the type of stimuli and the specific demands of the task. It was concluded that, since language has many components, dichotic listening can be used to investigate the relative contributions of the two cerebral hemispheres to those various components.

Adult↗

PubMedDate not supplied

Sodium phenylacetate (NaPa) induces modifications of the proliferation, the adhesion and the cell cycle of tumoral epithelial breast cells.

Sodium phenylacetate (NaPa), a physiological product of phenylalanine metabolism, present in micromolar concentrations in human plasma, has been shown to induce in vivo and in vitro cytostatic antiproliferative effects at millimolar concentrations. Cadherin molecules are powerful invasion suppressor molecules and the reduction of E-cadherin expression plays an important role in the invasion and metastasis of human breast cancer. In this study, we demonstrated, on one hand, that NaPa stimulated aggregation by increasing the expression of E-cadherin at the surface of breast cancer MCF-7ras cells transformed by Ha-ras oncogene and inhibited its expression in MCF-7 cells. We demonstrated that NaPa increased the formation of MCF-7ras cell aggregates and did not alter the formation of MCF-7 cell aggregates. By Northern blot, we demonstrated that the E-cadherin expression was not regulated at the transcriptional level. On the other hand, we analyzed the cell cycle of these 2 cell lines after NaPa treatment and showed that NaPa induced arrest at the G1/S phase in both MCF-7 and MCF-7ras cells. bFGF increased the growth of MCF-7 cells, but inhibited MCF-7ras cell proliferation. NaPa treatment suppressed the stimulation of MCF-7 cell proliferation and increased MCF-7ras cell growth inhibition. We have demonstrated a new target of NaPa action in blocking the cell cycle of tumor cells in G0/G1. We suggest that the anti-proliferative effect of NaPa associated to the restoration of the cadherin function in human mammary carcinoma cells indicates that NaPa could be a novel therapeutic agent in breast cancer.

Adenocarcinoma↗

PubMedDate not supplied

Influence of dentin conditioning and contamination on the marginal integrity of sandwich Class II restorations.

This study investigated the influence of dentin conditioning and contamination on the marginal adaptation of Class II sandwich restorations. Large butt-joint MOD cavities with cervical margins located 1 mm below the CEJ were cut into 72 extracted human molars. Nine groups were filled using a total-bond technique with Z100 or a sandwich technique with either Vitremer or F2000 in combination with Z100. For all three material combinations three different pretreatments were compared: total etch, selective etch and dentin contamination with saliva and blood prior to primer/adhesive application. After water storage for 21 days and thermocycling (2000x, 5-55 degrees C) replicas were produced for quantitative marginal analysis in the SEM. Teeth were immersed in 0.5% basic fuchsin for 24 hours and dried. Percent dye penetration over the total marginal length was analyzed in three layers using a sequential grinding technique. Statistical analysis was performed using a two-way ANOVA. Post-hoc analyses were carried out with univariate Mann-Whitney-U-tests adjusting for multiple comparisons by a sequentially rejective test procedure (Bonferroni-Holm) at p < 0.05. Both F2000 and Vitremer sandwich restorations showed better marginal adaptation than Z100 total-bond restorations with all pretreatments. Acid etching of the dentin significantly influenced the marginal adaptation of Z100 total-bond restorations and Vitremer sandwich restorations. All types of restorations showed considerable microleakage. On contaminated dentin, sandwich restorations showed better marginal integrity than total-bond restorations. Marginal adaptation did not correspond with microleakage in all groups. In conclusion, F2000/Z100 and Vitremer/Z100 sandwich restorations show better marginal adaptation than Z100 total-bond restorations in large Class II cavities with cervical margins in dentin. Microleakage cannot predictably be prevented with the sandwich technique. Sandwich restorations seem to be less sensitive to contamination with saliva and blood.

Acid Etching, Dental↗

PubMedDate not supplied

Sodium phenylacetate modulates the synthesis of autocrine and paracrine growth factors secreted by breast cancer cell lines.

Sodium Phenylacetate (NaPq) has been shown to suppress tumor growth and promote differentiation in experimental models. Thus, we have previously shown an inhibition of MCF-7ras cell proliferation by NaPa both in vitro and in vivo on xenographed tumors. In order to study the action of NaPa on the synthesis of paracrine or autocrine growth factors, conditioned media were prepared from breast pretumoral HBL100 cells, tumoral MCF-7 and MCF-7ras cells in the presence of NaPa. Growth factor activities of these media were tested on Balb c/3T3 fibroblasts and on the above breast tumor cells. Conditioned media from the 3 cell types contained different mitogenic activities when tested on the same cell lines. NaPa treatment for 24 hours inhibited differentially and dose-dependently the mitogenic activity of conditioned media. Inhibitions of HBL100 and MCF-7 cell proliferation by MCF-7ras medium conditioned with 20 mM NaPa reached 75% and 48% respectively. In contrast, NaPa treated MCF-7 conditioned medium decreased HBL100 and MCF-7ras proliferation by 49% and 72%, respectively, at the same NaPa concentration. The efficiency of NaPa inhibition reached an optimum as soon as one day after treatment. Among growth factors secreted by MCF-7 and MCF-7ras, TGF beta synthesis is inhibited and stimulated in MCF-7 and MCF-7ras cells respectively after NaPa treatment. We showed that NaPa modifies the synthesis of growth factors secreted by MCF-7 and MCF-7ras tumor cells leading to cell proliferation inhibitions. The synthesis of these previously identified factors was more involved in MCF-7 cells than fibroblast cell proliferation. In vitro and in vivo NaPa inhibition of MCF-7ras cells which secreted higher levels of these growth factors could be explained by this mechanism of action.

3T3 Cells↗