Demonstration of L1-related mRNAs in rat brain using DNA oligonucleotide probes

Only one copy of the cell adhesion molecule L1 gene is present in the mouse genome, and only one mRNA of 6 kilobases (kb) is expressed in mouse brain [1987, Neurosci. Lett. 82, 89-94]. We have constructed 5 synthetic oligonucleotide probes covering different parts of the published mouse L1 cDNA sequence. Using these probes 3 distinct mRNAs of 9.0, 7.0 and 6.0 kb in rat brain could be demonstrated. Hybridizations performed at different stringency conditions indicated that the 9.0 and 7.0 kb mRNAs were highly related to the L1 mRNA of 6.0 kb expressed in rat brain. The 7.0 kb mRNA is possibly coding for a rat homologue of chicken Nr-CAM, whereas the 9.0 kb mRNA may code for a new member of the L1 family.

Characterization of NCAM expression and function in BT4C and BT4Cn glioma cells

The neural cell adhesion molecule, NCAM, plays an important role in cell-cell adhesion. Therefore, we have studied NCAM expression in the glioma cell lines BT4C and BT4Cn. We demonstrate that the 2 cell lines differ in their metastatic ability; while BT4C cells have a very low capacity for producing experimental metastases, that of BT4Cn cells is high. In BT4C cells NCAM is synthesized as 4 polypeptides with Mr's of 190,000, 140,000, 115,000 and 97,000. The 140,000, 115,000 and 97,000 polypeptides are glycosylated and for the 140,000 and 115,000 polypeptides sulfatation is observed. Conversely, no NCAM protein synthesis is observed in BT4Cn cells, even though NCAM mRNA is expressed. Thus, development of an increased metastatic capacity is accompanied by the disappearance of NCAM protein expression in this model system. The functional importance of NCAM expression was studied by a cell-substratum binding assay in which the binding of BT4C and BT4Cn cells to NCAM immobilized to glass was assessed. We found that BT4C cells adhere specifically to NCAM, and that adhesion is inhibited by anti-NCAM Fab'-fragments, while no specific binding of BT4Cn cells to NCAM was observed. The BT4C and BT4Cn cell lines thus constitute an important new model system for the study of tumor invasion and metastasis and of the role of cell adhesion molecules in these processes.

NCAM in developing mouse gonads and ducts

The expression of the Neural Cell Adhesion Molecule, NCAM, in mouse gonads and ducts was studied from fetal life to maturity. The methods used were immunocytochemical staining and Western blotting. The immunocytochemical studies showed that the only structures that remain NCAM-positive throughout life were the mesonephric-derived rete ovarii and rete testis. Also in the fetal gonads some somatic cell lining the groups of differentiating germ cells were stained. In the immature as well as in the mature ovary the granulosa cells and oocytes of growing and large follicles--but not of small follicles--were stained. A particularly strong staining of the cytoplasm of the oocyte, healthy as well as atretic, was seen. All cells of the testis remained negative except for weakly stained residual bodies and late spermatids. At all ages the male ducts showed only weak staining, whereas in the female Müllerian duct the epithelium became strongly positive at puberty. The stroma of the Müllerian duct was positive during a transitory period around day 16 of fetal life in both sexes. One-dimensional gel immunoblotting of total protein from gonads, rete and ducts from immature and mature mice showed that only the two largest isoforms of NCAM (NCAM-A and NCAM-B) were present. The gonads and the rete of both sexes and the adult uterus expressed only NCAM-B, whereas NCAM-A was also detected in the adult epididymis. The present findings suggest that NCAM may be involved in the normal development and formation of both the gonads and ducts.(ABSTRACT TRUNCATED AT 250 WORDS)

Glial fibrillary acidic protein and beta A4 protein deposits in temporal lobe of aging brain and senile dementia of the Alzheimer type: relation with the cognitive state and with quantitative studies of senile plaques and neurofibrillary tangles

The aim of this study was to compare brain glial fibrillary acidic protein (GFAP) levels to the modifications of cognitive functions (Blessed test score [BTS]), the density of the main neuropathological lesions (senile plaques [SP] and neurofibrillary tangles [NFT]), and the density of the two main subtypes of beta A4 deposits (classic plaques and diffuse deposits) in a series of patients with normal aging and senile dementia of the Alzheimer type of various degrees of severity. GFAP levels (enzyme-linked immunosorbent assay [ELISA] technique) and the densities of changes were measured in the temporal lobe of 12 women over 75 years of age. Under these conditions, the ELISA assay could determine GFAP in brain homogenates (aqueous-Triton buffer soluble extract) in a range from 2.5 ng to 600 ng per assay. Least affected patients (with a BTS of 19 and over) all ranged below 60 micrograms/mg protein. Most affected patients (with a BTS under 6) ranged above 150 micrograms/mg protein. However, interindividual variations were wide. A significant correlation between the BTS and the amount of GFAP could be found only when using the non parametric test of Spearman. There was a significant positive correlation between the amount of GFAP and the density of 1) SP, 2) NFT both revealed by Bodian's silver stain, and 3) classic beta A4 plaques shown by immunocytochemistry. On the contrary, no correlation was observed with diffuse beta A4 deposits. One case with very large amounts of diffuse beta A4 deposits without SP or NFT showed no associated GFAP reactivity. This suggests that GFAP production is a critical event in the formation of classic SP.

The cell adhesion molecule Cell-CAM 105 is an ecto-ATPase and a member of the immunoglobulin superfamily

Cell-CAM 105 (C-CAM), a cell adhesion molecule in rat hepatocytes, was digested with trypsin, and peptides were isolated and sequenced by Edman degradation. The sequences of 4 peptides agreed with different regions of rat liver ecto-ATPase. Detailed biochemical analyses confirmed the identity between C-CAM and the ecto-ATPase. C-CAM/ecto-ATPase is a transmembrane protein having 4 immunoglobulin-like domains in the extracellular portion, demonstrating membership of the immunoglobulin superfamily. The ATPase activity suggests that ATP might influence cell adhesion, which would explain the inhibitory effect of exogenously added ATP on adhesion of several cell types.

Characterization of rat brain NCAM mRNA using DNA oligonucleotide probes

A number of different isoforms of the neural cell adhesion molecule (NCAM) have been identified. The difference between these is due to alternative splicing of a single NCAM gene. In rat brain NCAM mRNAs with sizes of 7.4, 6.7, 5.2, 4.3 and 2.9 kb have been reported. We have synthesized six DNA oligonucleotides, that hybridize to different exons in the NCAM gene. Furthermore we have constructed three oligonucleotides, that exclusively hybridize to mRNAs lacking certain exons, by letting them consist of sequences adjacent to both sides of the splice sites. By means of these probes we have characterized the five NCAM mRNAs in rat brain.

Characterization of N-cadherin mRNA in chicken brain and heart by means of oligonucleotide probes

It has previously been reported, that there is only one mRNA of 4.3 kb for chicken N-cadherin in brain and heart and one gene [(1988) J. Cell Biol. 106, 873-881]. Using three synthetic oligonucleotide probes derived from the published chicken N-cadherin cDNA sequence we found hybridization to at least four mRNAs in chicken brain and heart. The measured sizes were 8.0, 4.7, 3.8, and 3.3 kb. The 8.0 kb mRNA is only seen in brain, and only when a cytoplasmic probe is employed. The 3.8 kb mRNA is only observed in heart.

[Plasma level studies in volunteers after intramuscular injection of various doses of etofenamate in an oily solution]

Plasma level Studies on Volunteers after Intramuscular Application of Different Doses of Etofenamate in Oily Solution. After i.m. injections of etofenamate (active substance of Rheumon i.m.) in oily solution to 12 volunteers, courses of plasma levels of etofenamate, flufenamic acid and fenamate (sum of etofenamate and flufenamic acid) were measured by HPTLC. Maximum levels of etofenamate, flufenamic acid and fenamate, as well as areas under the plasma level time curve (AUC) after 250, 500 and 1000 mg etofenamate respectively are proportional to dose. Maxima of fenamate plasma levels are reached after 6.3, 6.2 and 5.4 h respectively, half maximal levels are present already after 2 h. The mean residence time is 21.8, 18.8 and 15.7 h. These values obtained from different doses are not statistically different from each other. Pharmacokinetics are therefore linear and dose independent. The courses of fenamate levels can be described by a two compartment model. The elimination half lives after 250, 500 and 1000 mg are 2.1, 2.3 and 1.9 h, the invasion half-lives (dominant half-life) 8.8, 7.8 and 6.8 h. Terminal half-lives are 50.3, 63.7 and 35.4 h. Since plasma levels have decreased to 2% of the maximum level after one terminal half-life, they have no practical importance for the duration of activity or for accumulation. No sex related differences are found for dose dependent and independent parameters. From the data it can be derived that after i.m. injection of etofenamate in oily solution a prolongation of the dominant half-life occurs by a factor of 4-5 (as compared to oral data) which is caused by prolonged liberation from the oily depot. This long lasting liberation of etofenamate leads to a prolonged residence time after a fast increase, at the same time avoiding unnecessary high peak levels. Therefore it is guaranteed that even after i.m. administration of 1000 mg etofenamate in oily solution plasma levels of fenamate do not exceed those after 300 mg given orally. According to pharmacokinetic data a fast onset of action, good tolerability and a therapeutic action over a period of 24 h can be expected.

Expression of neural cell adhesion molecule-related sialoglycoprotein in small cell lung cancer and neuroblastoma cell lines H69 and CHP-212

Monoclonal antibodies (MAbs) 123C3 and 123A8 generated against a membrane preparation of a small cell lung carcinoma (SCLC) specimen recognize not only SCLC and bronchial carcinoids but also a significant portion of non-small cell lung carcinomas (non-SCLC) of various histological types. Together with 13 other monoclonal antibodies, which show preference for SCLC, they have been ranked as SCLC cluster 1 (SC-1) Mabs. In this study we show that SC-1 MAbs are directed against a restricted number of epitopes, and that SC-1 MAbs and a polyclonal antiserum directed against the neural cell adhesion molecule (NCAM) recognize identical glycoproteins, indicating that SC-1 antigens are closely related to or identical with NCAM. Long polysialic acid units composed of alpha-(2,8)-linked N-acetylneuraminic acid units, which in mammals are found exclusively on NCAM, were present on SC-1 antigens in SCLC. This provides further evidence that SC-1 MAbs recognize NCAM. The SC-1 antigens in the SCLC cell line H69 were present in two forms, NCAM-containing alpha-(2,8)-polysialic acid units identified by antiserum 735, the NCAM-H form, and the less sialylated NCAM-L form. The NCAM-H form consisted of diffusely migrating sialoglycoproteins with a molecular weight of 200,000-250,000, which resolved after neuraminidase treatment into two proteins with molecular weights of 140,000 and 180,000. Since the NCAM-H form is expressed in the lung tumor type with a poor prognosis, our results suggest that NCAM might be implicated in the invasive behavior of these NCAM-positive lung tumors.

A developmental study of soluble L1

L1 is a neural cell adhesion molecule expressed by neurons and it is involved in cell interactions during axon elongation and fasciculation. L1 from rat brain consists of a membrane-inserted Mr 200,000 polypeptide from which two polypeptides of Mr 180,000 and Mr 140,000 can be derived. These latter polypeptides appear both as membrane-associated and as soluble molecules. In this report, both total and soluble L1 in rat brain have been quantified by an enzyme-linked immunosorbent assay. The amount of total L1 per gram brain varies with postnatal age showing a peak value at postnatal day 7. The variation in soluble L1 coincides with the changes in total L1. Thus, soluble L1 constitutes ca 2% of total L1 at all ages investigated. The soluble Mr 140,000 and 180,000 L1 polypeptides are also present in cerebrospinal fluid. Studies of membrane L1 catabolism in cultured fetal rat brain neurons show that the half-life of membrane L1 is less than 24 hr. As a part of membrane L1 catabolism, small amounts of soluble L1 polypeptides are released to include cell surroundings.

Dystrophin in electric organ of Torpedo californica homologous to that in human muscle

We have found that dystrophin is highly concentrated at neuromuscular junctions and innervated membranes of the electric organ of Torpedo californica. In acetylcholine receptor-rich Torpedo membrane preparations dystrophin represents approximately 0.4% of total protein and can be extracted from these membranes by alkaline treatment in the absence of detergent, indicating that it is a peripheral membrane protein. Polyclonal antibodies raised against electrophoretically isolated Torpedo dystrophin cross-react with dystrophin in human muscle and unequivocally discriminate between normal and Duchenne muscular dystrophy patient's muscle. These results indicate that dystrophin is phylogenetically a highly conserved protein and that the relatively abundant dystrophin in electric organ would facilitate further investigations of its structure and function.

[Ultrasound-guided prostatic biopsy using biplanar transrectal probe. Our experience]

In the last three years we performed more than 200 echo-guided prostatic biopsies using different probes. Recently, thanks to the availability of a bi-planar transrectal probe we have developed a technique that resulted simple rapid well accepted by the patients and above all able to center small prostatic nodules. We have studied with this technique 96 patients performing 120 biopsies. For the biopsy we used a 19 G cutting-needle introduced under local anaesthesia parallel to the probe (linear array) when the needle is on the target we turn on the axial view and we check the position with respect to the center of the lesion, then, returning to the sagittal view we perform 1 to 3 biopsies for microhistological and cytological examination. With this method we have reached a better accuracy of diagnosis.

Heterogeneity of soluble neural cell adhesion molecule

Soluble neural cell adhesion molecule (NCAM) from rat brain neuronal cell culture media consists predominantly of a polypeptide of Mr approximately 115,000. Minor amounts of a polypeptide of Mr approximately 180,000 and two inconsistently appearing components of Mr 160,000 and 145,000 are also observed. The Mr 115,000 component is derived from the neuronal membrane NCAM components NCAM-A of Mr 190,000, NCAM-B of Mr 140,000, or both. Thus, as a part of the catabolism of membrane NCAM-A plus -B, a minor fraction is posttranslationally cleaved and recovered in the media as discernible soluble NCAM polypeptides. The half-life of membrane NCAM-A plus -B is less than 24 h. Astrocyte culture media contains a predominant soluble NCAM component of Mr 120,000 derived from membrane-associated NCAM-C. A close comparison of deglycosylated soluble NCAM from astrocyte and neuronal cultures showed a small but consistent difference in Mr, a result suggesting that different NCAM polypeptides are released from the membrane of neurons and astrocytes. In contrast to the Mr 115,000-120,000 NCAM polypeptides, the Mr 180,000 polypeptide from neuronal culture media does not seem to be derived from membrane-attached NCAM and may therefore represent a secreted NCAM isoform.

Treatment of carbamazepine poisoning by combined hemodialysis/hemoperfusion

A severe carbamazepine intoxication in a 45-year-old woman was treated with combined hemodialysis/hemoperfusion. The ingested dose was estimated as 4-36 g. Serum carbamazepine levels were determined by fluorescence polarization immunoassay. The detoxication was performed 18 h after admission and resulted in a 50 percent reduction in serum drug levels accompanied by rapid clinical improvement.