Two-compartment model for rabbit skin organ culture.

A new method was developed for rabbit skin organ culture. In a two-compartment model, skin discs were cultured on a Millicell-HA insert unit with a microporous membrane which allows transport of culture medium via the dermis into the epidermis, whereas the epidermal side remains free of direct contact with culture medium. In this relatively simple two-compartment organ culture model, rabbit skin could be cultured for 7 d in RPMI 1640 medium supplemented with fetal bovine serum, or for 2 d in RPMI 1640 medium supplemented with cofactors. The histomorphology and ultrastructure of 7-d cultured rabbit skin discs was essentially similar to that of freshly isolated rabbit skin. Keratinocytes in the stratum basale continued to divide during organ culture. The terminal differentiation of the epidermis continued in vitro as was found by the presence of keratohyalin granules, the intact stratum corneum, and keratin expression. Furthermore, glucose consumption continued until culture Day 7, but thereafter it declined rapidly. Concomitantly, degenerative changes were found. At the end of the 7-d culture period the distance between single dermal collagen fibrils had increased as compared to noncultured skin. This model of skin organ cultures can be used to study biological processes, dermal toxicity, and penetration and metabolism of xenobiotics in intact skin. Furthermore, within certain limits, processes responsible for repair and regeneration of damaged skin can also be studied in this model because the rabbit skin can be cultured for 7 d.

Latex immunoassay of serum alpha-fetoprotein using polyethylene glycol pretreatment.

A latex particle immunoassay has been developed for the determination of serum alpha-fetoprotein. The assay consists of incubating the serum sample for 30 min at 50 degrees C with latex particles coated with anti-alpha-fetoprotein immunoglobulin, then quantifying the remaining unagglutinated particles with an optical particle counter. The assay is fully automated with a sampling rate of 40/h. The interference from rheumatoid factor is eliminated by precipitation with polyethylene glycol (7% final concentration). The alpha-fetoprotein standard curve, prepared in a human serum matrix, extends from 0.5 to 32 micrograms/l. Because sera are diluted ten-fold, the limit of detection of the assay lies around 5 micrograms/l. Coefficients of variation ranged from 4 to 15% and the recovery of alpha-fetoprotein tested on eight normal sera and four sera containing rheumatoid factor averaged 102.2% (SD = 13.2). The correlation coefficient between latex immunoassay and radioimmunoassay, calculated from the assay of 138 samples was 0.98.

[Demonstration of anti-laminin antibodies in the serum of healthy subjects]. / Mise en évidence d'anticorps antilaminine dans le sérum de sujets sains.

Antibodies directed against laminin, a glycoprotein of basement membranes, have been sought for in the sera of 347 healthy subjects by a method relying on the agglutination of laminin-coated latex particles. Fifty-five subjects (15.9%) hae been found to be positive, 37 with a titre of 2, 14 with a titre of 4 and 4 with a titer of 8. Applied to 106 patients whose a renal biopsy had been examined by immunofluorescence, the test yielded positive results in 91% of patients with linear deposits as compared to 10.3 and 15.4% respectively in patients presenting with and without granular deposits along the glomerular basement membrane. The titers in anti-laminin antibodies observed in these patients ranged from 2 to 8. The discovery of circulating anti-laminin antibodies in serum from subjects without clinical or subclinical sign of renal impairment rises several questions regarding the pathogenicity of these auto-antibodies and their possible association with genetic or environmental factors.

The abilities of the rat brain to sustain the survival of implanted or cultured embryonic dorsal root ganglion neurons depend on the selected region.

The purpose of the present study was to examine the regional distribution of trophic activity in the lesioned adult rat brain on implanted peripheral neurons as target cells. Embryonic dorsal root ganglia (DRG) were implanted into selected regions of previously lesioned adult rat brains. The survival of these neurons was quantified after thirty days. In another experiment embryonic DRG neurons were cultured for 24 h together with tissue extracts of the same lesioned brain regions and the neuronal survival was estimated. We report here that all the tested regions, i.e. the occipital, parietal and frontal cortex, the hippocampus and the striatum, exert a trophic effect on embryonic DRG neurons both 'in vivo' and 'in vitro'. This effect is twice as high in the hippocampus as in the striatum, the other cortical regions showing intermediate values. The in vitro results are qualitatively the same as the in vivo results.