The glial fibrillary acidic protein (GFAP) is the subunit protein of intermediate filaments in astrocytes and closely related cell types. By means of an enzyme immunoassay we have determined the concentration of GFAP in amniotic fluids from normal pregnancies and from pregnancies complicated by various fetal malformations. The group of 20 cases of fetal anencephaly had a significantly higher mean amniotic fluid GFAP concentration (115 micrograms/l +/- 133.6 (S.D.), range 6-378 micrograms/l) than the control group of 117 normal pregnancies (13 micrograms/l +/- 5.5 (S.D.), range 0-31 micrograms/l), (P less than 0.001). Two cases of fetal encephalocele likewise had very high amniotic fluid GFAP concentrations. None of the other cases of fetal malformations investigated, including 12 cases of spina bifida, had increased amniotic fluid GFAP concentrations. We conclude that determination of the amniotic fluid GFAP concentration may give additional information in the prenatal diagnosis of fetal nervous system malformations.

Amniocentesis↗

PubMedDate not supplied

Molecular biology of cadherins in the nervous system.

Cadherins are cell-cell adhesion molecules belonging to the Ca(2+)-dependent cadherin superfamily. In the last few years the number of cadherins identified in the nervous system has increased considerably. Cadherins are integral membrane glycoproteins. They are structurally closely related and interspecies homologies are high. The function is mediated through a homophilic binding mechanism, and intracellular proteins, directly or indirectly connected to the cadherins and the cytoskeleton, are necessary for cadherin activity. Cadherins have been implicated in segregation and aggregation of tissues at early developmental stages and in growth and guidance of axons during nervous system development. These functions are modified by changes in type(s) and amount of cadherins expressed at different developmental stages. The regulatory elements guiding cadherin expression are currently being elucidated.

Amino Acid Sequence↗

PubMedDate not supplied

Biological effects of magnetic fields: chronic exposure of the nematode Panagrellus redivivus.

The Panagrellus redivivus bioassay, an established monitor of adverse toxic effects of different environments, has been used to study the biological effects of exposure to static and time-varying uniform and gradient magnetic fields, and to time-varying magnetic field gradients superimposed on a static uniform magnetic field of 2.35 Tesla. Temporally stationary magnetic fields have no effect on the fitness of the test animals. Time-varying magnetic fields cause some inhibition of growth and maturation in the test populations. The combination of pulsed magnetic field gradients in a static uniform magnetic field also has a small detrimental effect on the fitness of the test animals.

Animals↗

PubMedDate not supplied

Degenerative cartilage lesions of the hip--magnetic resonance evaluation.

The capability of magnetic resonance imaging (MRI) to visualize early degenerative arthritis of the hip was investigated. The study was performed on 8 healthy students and 45 elderly volunteers. Images were obtained by using an electronically variable Helmholtz coil (switched-array coil, SAC). In order to diagnose degenerative lesions of the joint cartilage, FISP sequences with a flip angle of 70 degrees were found preferable to compared sequences. MRI-detectable signs of degenerative arthritis of the hip were narrowed joint space due to partially thinned cartilage layers, focal areas of either increased or decreased signal intensity in the hyaline cartilage, complete loss of cartilage, and signal variation in the bone marrow. MRI of the hip may be appropriate to detect early degenerative changes in the hips of young high-risk patients to facilitate therapy planning.

Aged↗

PubMedDate not supplied

The neural cell adhesion molecule (NCAM) in development and plasticity of the nervous system.

The neural cell adhesion molecule (NCAM) is a member of the immunoglobulin superfamily and is strongly expressed in the nervous system. NCAM is found in three major forms, of which two--NCAM-140 and NCAM-180--are transmembrane proteins, while the third--NCAM-120--is attached to the membrane via a glycosylphosphatidyl inositol anchor. In addition, soluble NCAM forms exist in brain, cerebrospinal fluid, and plasma. NCAM mediates cell adhesion through homophilic as well as through heterophilic interactions. Following NCAM binding, transmembrane signalling is believed to be activated, resulting in increased intracellular calcium. By mediating cell adhesion to other cells and to the extracellular matrix and by activating intracellular signaling pathways, NCAM influences cell migration, neurite extension, and fasciculation, and possibly formation of synapses in the brain. From studies on NCAM knock-out mice, NCAM have been shown to be crucial for the formation of the olfactory bulb and the mossy fiber system in the hippocampus. In addition, NCAM is important for neuronal plasticity in the adult brain associated with learning and regeneration.

Aging↗

PubMedDate not supplied

The neural cell adhesion molecule in synaptic plasticity and ageing.

By mediating cell adhesion and signal transduction, the neural cell adhesion molecule (NCAM) regulates neurite outgrowth, fasciculation and target recognition in the developing nervous system. In addition, a number of studies suggest an important role for the NCAM in regeneration and learning in the adult nervous system. NCAM-deficient mice are impaired in spatial learning. Moreover, by interfering with normal NCAM function by intracranial injections of NCAM-antibodies, long-term potentiation (LTP) in rat hippocampal slices and learning in rats and chicks have been inhibited. In the vertebrate nervous system, NCAM is the dominant carrier of polysialic acid (PSA), an unusual carbohydrate consisting of long homopolymers of sialic acid. The PSA-NCAM expression decreases markedly during development. However, an upregulation of polysialic acid (PSA) in restricted brain areas including the hippocampus has been observed following learning. Moreover, enzymatic removal of PSA results in impaired LTP and learning. In muscle, the PSA-NCAM expression is upregulated following denervation. This response is weakened in aging rats. The expression of NCAM and PSA have been shown to be regulated by neuronal activity suggesting that the NCAM may promote structural remodelling in an activity dependent manner associated with learning and regeneration.

Aging↗

PubMedDate not supplied

Glial cells express N-CAM/D2-CAM-like polypeptides in vitro.

The joining together of neurites to form fascicles and the growth of axons along glial surfaces during early development suggest that neurone-neurone and neurone-glial adhesion interactions are of considerable importance for defining nerve tracts. In vitro studies have indicated that adhesion between neurones involves a glycoprotein that has been independently studied under the names of N-CAM (for neural cell adhesion molecule), D2-CAM and BSP-2 (refs 10, 11). As N-CAM/D2-CAM appears to be a homophilic ligand that binds to N-CAM/D2-CAM polypeptide on adjacent cells, this glycoprotein is potentially important in adhesion interactions between any two N-CAM/D2-CAM-expressing cells. While it has been suggested that neurone-glial adhesion involves molecules other than N-CAM/D2-CAM, it is known that N-CAM/D2-CAM antigenic determinants are expressed by glial cells in vivo and that injection of anti-N-CAM antibodies into the eye-cup of chick embryos disrupts normal patterns of neuritic apposition to glial endfeet in the developing optic stalk. Do the molecules expressed by glia share restricted antigenic determinants, or binding domains, with N-CAM/D2-CAM, or are N-CAM/D2-CAM polypeptides expressed by glia? Here we present immunocytochemical evidence which suggests that all classes of macroglia express N-CAM/D2-CAM antigenic determinants on their surfaces and immunochemical analyses which indicate that the molecules expressed by purified astrocytes are closely similar, or identical, to at least some forms of N-CAM/D2-CAM obtained from whole brain or purified neurones. However, our results also suggest that different N-CAM/D2-CAM polypeptides may be separately expressed by neurones and astrocytes.

Animals↗

PubMedDate not supplied

Ecto-protein kinase activity on the external surface of neural cells.

ATP is secreted in association with neurotransmitters at certain synapses and neuromuscular junctions. Extracellular ATP is known to exert potent effects on the activity of cells in the nervous system, where it can act as a neurotransmitter or as a modulator regulating the activity of other neurohormones. We have suggested that such modulation may involve the activity of extracellular protein phosphorylation systems. It is well known that intracellular protein kinases are important in the regulation of various neuronal functions, but protein kinases which use extracellular ATP to phosphorylate proteins localized at the external surface of the plasma membrane (ecto-protein kinases) have not been demonstrated in neuronal cells. Here we present direct evidence for the existence of an ecto-protein kinase and demonstrate endogenous substrates for its activity at the surface of intact neural cells. The phosphorylation of one of these surface proteins is selectively stimulated during cell depolarization. In addition, neuronal cell adhesion molecules (N-CAMs) appear to be among the substrates of ecto-protein kinase activity. These results suggest a role for surface protein phosphorylation in regulating specific functions of developing and mature neurones.

Adenosine Triphosphate↗

PubMedDate not supplied

[Radiofrequency thermal ablation of hepatic nodules: selection criteria for percutaneous treatment].

Radiofrequency thermal ablation (RFA) of liver tumor is done by percutaneous, laparoscopic and open surgical approach. Selection criteria for percutaneous or open surgical ablation of 54 hepatic lesions are here evaluated in 30 consecutive patients. Open surgical approach was performed in 9 cases only, 5 of them due to concomitant treatment of associated diseases. Number and size of the lesions did not interfere with surgical approach. Postoperative CT control showed no differences in terms of complete ablation of the tumor in between the two groups of patients. Percutaneous approach of RFA is gone to be in the future the modality of choice in these patients.

Catheter Ablation↗

PubMedDate not supplied

Contrast-enhanced ultrasonography with SonoVue after infliximab therapy in Crohn's disease.

The introduction of biological treatments like monoclonal anti TNF-a antibodies (infliximab), is changing the clinical history of Crohn's disease (CD). The effects of these therapies are monitored emplying clinical indexes of active disease, laboratory parameters, endoscopy and histology, and also with imaging techniques. A new ultrasound contrast agent, SonoVue (Bracco SpA, Milano, Italy), is opening new perspectives in the study of microvasculature of several organs. Aim of this study is to evaluate by SonoVue enhanced ultrasonography (US) the occurrence of modifications in bowel wall microvasculature of CD patients and to correlate them with parameters of disease activity and to follow up the findings during infliximab therapy. After performing a basal color-doppler ultrasonography, the study of the affected bowel loop is performed after i.v. injection of SonoVue and the enhancement is evaluated on a qualitative basis. We report on the preliminary results obtained in twenty patients, eight of which have been treated with three infusions of infliximab (induction cycle) and evaluated at baseline and after the treatment. While at baseline we describe a positive correlation of SonoVue enhancement of the affected bowel loop with CRP, alpha1-glycoprotein and white blood cell number, after infliximab treatment in 6/8 cases a definite improvement was detected. Ultrasonographic evaluation of the changes of bowel wall enhancement after i.v. SonoVue during infliximab therapy might represent an useful, not invasive and relatively low cost imaging modality for the clinical monitoring of activity of small bowel Crohn's disease.

Adult↗