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Biomedical subjects

D Imbert

Publications and source records attributed to D Imbert.

17 recordsLinked to original sources
PubMed2001

New 8-hydroxyquinoline and catecholate iron chelators: influence of their partition coefficient on their biological activity.

Four new hexadendate chelators, three hydroxyquinoline-based, Csox, O-Trensox, Cox750, and one catecholate-based CacCam-which have comparable skeletal structures and pFe, but widely different partition coefficients, (Kpart), 0.01, 0.02, 1 and 3.2 respectively, have been tested for their iron chelating efficacy in vitro by two methods. First, by their ability to remove iron from ferritin in solution or second, to remove iron from iron-loaded hepatocytes in vitro. Our objective was to ascertain the importance of Kpart and pFe, on the biological efficiency of the molecule. Previous studies proposed that an ideal value of Kpart of 1 should give maximum biological activity. Mobilization of iron by Csox and CacCAM from ferritin was similar and furthermore more efficient than desferrioxamine B. In the iron-loaded hepatocyte cultures, the three hydroxyquinoline chelators, although showing diversity in terms of lipophilicity, appeared to be very similar in their capacity to chelate iron. CacCAM, the unique catecholate, was the most efficient of the molecules tested, as well as being the least toxic in the cellular model despite having the lowest value of pFe. In conclusion, the use of the partition coefficient and pFe, as tools for predicting biological activity of iron chelators should be not generalized. Further studies are required in order to understand the influence of the structure on the biological activity of the molecule.

Animals↗
PubMed2000

A quantitative minimally invasive assay for the detection of metals in the stratum corneum.

A quantitative, minimally invasive tape-stripping assay for the detection of metals on and in skin that also has application to the detection of metallic elements on dry surfaces (where human contact could occur) has been developed. This development included construction, using commercial products, of an approximately 25 microm thick, low-metal content tape suitable both for tape-stripping and elemental analysis. Individual tapes were sequentially applied to the skin surface and then removed, taking with them a sample of the dead outer layer of the skin (stratum corneum). Analysis of such tape strip samples by particle induced X-ray emission (PIXE)--a well-characterized, sensitive, analytical technique based on X-ray spectrometry--identified and accurately quantified the metals in the sample. The assay had elemental sensitivities of approximately 1 ng/cm2 for many metals and analysis of elemental contents could be performed in as little as 5 min. The feasibility of the assay for measuring metals in the stratum corneum was demonstrated on the forearms of healthy human volunteers. Samples from approximately half the subjects were found to contain zirconium, possibly arising from the use of roll-on antiperspirants. The assay has potential as a tool: (1) for risk assessment, (2) to identify exposure levels following possible contact with a hazardous metal, and (3) to determine the effectiveness of cleanup or removal measures.

Humans↗
PubMed1999

Partition coefficients (free ligands and their iron(III) complexes) and lipophilic behavior of new abiotic chelators. Correlation to biological activity.

Partition coefficients between n-octanol and water have been measured for ten tripodal ligands with catecholate or hydroxyquinolinate or pyridinophenolate chelating subunits and for their iron(III) complexes. The abilities of the ligands to cross an octanol phase and to extract ferric ion from its EDTA complex in an aqueous phase are studied. Correlation with biological properties are discussed.

Ferric Compounds↗
PubMed1999

Buccal mucosa in vitro experiments. I. Confocal imaging of vital staining and MTT assays for the determination of tissue viability.

Delivery of drugs through the skin and the buccal mucosa has been considered as an alternative to per oral dosing for those substances that are degraded in the gastro-intestinal tract, or are subject to first-pass metabolism in the liver. In the buccal mucosa, contrary to skin, the diffusion barriers are located within living cell layers, hence the physiological state of the tissue is likely to significantly affect in vitro diffusion profiles. In this study, we were interested in assessing the viability of excised buccal mucosa and determining the limits of tissue usage under common in vitro experimental conditions. Using confocal laser scanning microscopy (CLSM), we have shown that optical sectioning of samples exposed to calcein AM and ethidium homodimer-1 (used as 'live' and 'dead' cell probes respectively) can be employed to accurately and reliably determine the viability of buccal mucosa biopsies. The results of the CLSM assay were remarkably consistent with that of an MTT assay. In both studies, viability in PBS at 34 degrees C was lost after about 8 h post-mortem, whereas it could be sustained for up to 24 h in KBR.

Animals↗
PubMed1997

Assessment of cornea viability by confocal laser scanning microscopy and MTT assay.

PURPOSE: Determination of excised cornea viability is of interest for transplant-storage evaluation, but also for in vitro diffusion-study design and ocular-toxicity assessment. By using simultaneous vital staining by calcein AM (CAM) and ethidium homodimer-1 (EH-1), as "live" and "dead" probes, respectively, we developed a confocal laser scanning microscopy (CLSM) assay to determine epithelial and endothelial viability and estimate cornea thickness. METHODS: New Zealand White rabbit corneas were stored in phosphate-buffered saline (PBS) or Optisol at 4 degrees C or at room temperature. At various times, corneas were stained with an EH-1/CAM solution and observed, without further treatment, by CLSM. Storage effects on the cornea were also assessed by using an MTT assay. RESULTS: Stromal swelling, shedding of the upper epithelial layers, and severe endothelial damage were observed after 4 h in PBS at room temperature. After 8 h, lower epithelial cell death was observed, along with loss of endothelial structure. Corneas stored in similar conditions in Optisol were indistinguishable from controls. Storage in Optisol at 4 degrees C affected the superficial layers of the corneal epithelium similarly at both 7 and 14 days. Extensive epithelial shedding and wing-cell death were observed at 25 days, but the basal layer remained approximately 50% healthy. Significant endothelial cell loss was observed at 25 days. MTT results were consistent with CLSM data in the medium-term storage study only. CONCLUSIONS: This CAM/EH-1 CLSM fluorescence assay is a sensitive index of viability in cornea, and thus may prove useful in investigations in which maintenance of vital functions in different cell layers is critical.

Animals↗
PubMed1976

[Psychiatric effects of cardiac surgery].

The authors report three cases of psychotic complications of cardiac surgery. A review is made from literature and an inventory of psychological and organic factors implicated in this pathology. These complications are still frequent (up to 50% for Braceland, and 70% for Rabiner and al.). For Blacher there is an almost universal "psychosis" in by-pass surgery and frequent "hidden psychosis" (they are ignored and denied both by the staff and the patient). They are caused by the emotional stress, intensive care unit syndrome, or personal vulnerability. The symbolism of the heart and the personality of the cardiac patient are also in cause. Neurologic accidents, hypoxy, embolisms, are now less frequent. The collaboration of a psychiatrist with the cardiologic staff is mandatory. With this collaboration not only psychiatric complications but also somatic morbidity and mortality would be reduced.

Adjustment Disorders↗
PubMedDate not supplied

[Modern aspects in management of psychotic children (author's transl)].

The idea of hope is paramount in the management of psychotic children. The different alternatives were developed with reference to the modern conceptions of the psychoanalytical theory. Day hospitals, each of which admits children from a given district, seem to allow optimal active therapy. Management includes: individual psychoanalysis for the child; life groups to which the child belongs during the day; a consistent institutional policy based on psychoanalytical theories; leaving the child with it's own or an auxiliary family and supporting this family; minimal chemotherapy. The authors report major improvement or recovery in one-third to one-half of the children.

Child↗