Per P. Clausen

Intracellular plasma proteins in human fetal choroid plexus during development II. The distribution of prealbumin, albumin, alpha-fetoprotein, transferrin, IgG, IgA, IgM, and alpha1-antitrypsin

Individual choroid plexuses of human fetal brain at different developmental stages were investigated by an indirect immunoperoxidase technique. The number and distribution of prealbumin-, albumin-, alpha-fetoprotein-, transferrin-, IgG-, IgA-, IgM- and alpha 1-antitrypsin-containing choroid plexus epithelial cells were recorded. The distribution of prealbumin in choroid plexus epithelial cells differed from that of other plasma proteins identified in these cells. Prealbumin was present in more than 90% of the cells at all ages examined in contrast to albumin, alpha-fetoprotein, transferrin and IgG, which were found in less than 40% of the cells, and this proportion declined later in gestation to only a few per cent. The telencephalic plexus exhibited a staining pattern for the proteins, except for prealbumin, which was different from that of the diencephalic and myelencephalic plexuses. Double-staining and staining with polyvalent antiserum indicated that the same epithelial cells showed positive reaction for albumin, alpha-fetoprotein, transferrin and IgG. The results are related to the observation of a high concentration of plasma protein in fetal CSF which may result from transcellular transfer from blood to CSF across the choroid plexus epithelial cells.

Intracellular plasma proteins in human fetal choroid plexus during development I. Developmental stages in relation to the number of epithelial cells which contain albumin in telencephalic, diencephalic and myelencephalic choroid plexus

The developmental stages of telencephalic, diencephalic and myelencephalic choroid plexuses in the human fetus and the morphology of choroid plexus epithelial cells in the various plexuses in different development stages were described on basis of PAS- and toluidine blue-stained material. Six different cell types were identified in various combinations in 4 different stages (I-IV). The number and distribution of albumin-containing epithelial cells in various plexuses in the different stages of development were investigated by indirect immunoperoxidase technique. Albumin-containing cells did not belong to a single cell type. The telencephalic plexus exhibited a staining pattern for albumin which was different from that of the diencephalic and myelencephalic plexuses. In the telencephalic plexus positive epithelial cells were frequent in stage I, whereas only a few positive cells were present in stage II and III. In contrast, 30-40% of the epithelial cells in both diencephalic and myelencephalic plexuses in stage I, II and III showed a positive staining reaction. Later in gestation less than 10% were positive. It is suggested that a main function of the diencephalic and myelencephalic plexuses early in gestation is associated with protein transport rather than with glycogen synthesis and storage which might be a major function of the telencephalic plexus.

Purity of commercial non-certified European samples of Pyronin Y.

SummaryThe purity of six European non-certified samples of Pyronin Y was compared with that of two American samples certified by the Biological Stain Commission. The methods used were spectrophotometry and a Methyl Green-Pyronin staining test (both as applied by the Biological Stain Commission), thin layer chromatography, mass spectrometry, determination of pH, and content of some electrolytes. It was found that none of the European batches of Pyronin Y passed the complete test as prescribed by the Biological Stain Commission. Their dye content was uniformly low (between 5 and 19%). Furthermore, thin layer chromatography and mass spectrometry revealed that two of the dye samples contained no Pyronin Y or only traces.It is concluded that assessment of an unknown sample of a dye labelled Pyronin Y should be initiated with thin layer chromatography. The pH and content of electrolytes in an aqueous solution of the dye should also be determined in order to obtain reproducible staining results. Finally, the value of the work performed by the Biological Stain Commission is underlined, although more sophisticated methods are necessary for testing the purity of dyestuffs.

Immunohistochemical demonstration of tumour associated antigens in carcinoma‐in‐situ of the testis

Atypical germ cells or so-called carcinoma-in-situ of the testis are often found in the tissue adjacent to germ cell tumours. The present study was performed to investigate if tumour associated antigens demonstrated immunohistochemically in the tumours could also be demonstrated in the carcinoma-in-situ. Using indirect immunoperoxidase technique 39 orchidectomy specimens were examined for the presence of a series of antigens: alpha-foetoprotein (AFP), alpha1 -antitrypsin (A1 AT), human chorionic gonadotrophin (hCG). specific pregnancy β-glycoprotein (SP1 ), human placental lactogen (hPL), carcino-embryonic antigen (CEA) and ferritin (FER). FER was demonstrated in the atypical cells in 24/29 cases of carcinoma-in-situ of the testis. HCG was demonstrated in intratubular syncytiotrophoblast-like cells in one case and in atypical germ cells in another specimen. No staining reaction was found for the other antigens investigated Normal germinal epithelium and germinal epithelium in non-malignant pathological changes of the testis were never stained. These findings which indicate that FER may be a possible marker of carcinoma-in-situ of the testis is of utmost interest, however investigation of a larger series is mandatory.