Expression of the neural cell adhesion molecule NCAM in endocrine cells

We examined the expression of the neural cell adhesion molecule NCAM in a number of endocrine tissues of adult rat and in an endocrine tumor cell line. NCAM was found by immunoelectron microscopy to be present on the surface of all endocrine cells in the three lobes of the hypophysis, although staining was relatively less intense in the intermediate lobe, and in pancreatic islets. Pituicytes, hypophyseal glial cells, were also labeled for NCAM. A rat insulinoma cell line (RIN A2) also expressed NCAM as judged by immunocytochemistry. Analysis of NCAM antigenic determinants (Mr 180, 140, and 120 KD) revealed large variations in the relative proportions of NCAM polypeptides present in the different tissues. Although all tissues and cell lines expressed NCAM-140, NCAM-180 was not detected in the adenohypophysis, pancreas, or adrenal medulla, and NCAM-120 was found in none of the endocrine tissues or cell lines except at low levels in the neurohypophysis. The tumor cell line expressed significant levels of NCAM-180, which was most abundant in the neurohypophysis. These results show that NCAM expression appears to be a general property of endocrine cells, although the antigenic composition differs markedly from that in brain tissue. These data are discussed with regard to the embryological origins of the different endocrine tissues, and possible functional implications are suggested

Differential expression of the neural cell adhesion molecule NCAM 140 in human pituitary tumors

We have analyzed the expression of the intracellular marker protein neuron specific enolase (NSE), synaptophysin (SYN) and of the cell surface marker NCAM (neural cell adhesion molecule) in both normal human hypophysis and in pituitary adenomas in order to explore their potential use as diagnostic tools. All adenomas (4 prolactinomas, 3 growth hormone (GH) producing adenomas and 4 inactive adenomas) showed SYN and NSE immunoreactivity on tissue sections and this was confirmed by immunoblots. NCAM 140 (an isoform of NCAM with molecular mass 140 kDa) was detected by immunoblotting in normal human adenohypophysis, in all GH adenomas, and in three out of four inactive adenomas, but not in prolactinomas. Using highly sensitive techniques, NCAM immunoreactivity was observed by electron microscopy in all adenomas. These data indicate that NCAM 140 is a constituent of the cell surface of endocrine cells in both normal human adenohypophysis and its tumors. Since prolactinomas express very low levels of NCAM 140 compared to other hypophyseal tumors its virtual absence could be used for differential diagnosis. A combined analysis of NCAM, SYN and NSE could be useful to characterize inactive adenomas which are not immunoreactive for pituitary hormones and which may contain no or only low levels of the alpha chain of the glycoprotein hormones

A laboratory incubator equipped with facilities to automatically simulate natural irradiance

An incubator is described which automatically simulates fluctuations of natural irradiance by coupling a photocell to a lightbank in the ship's laboratory. Design details are given

Unterabtastendes Mehrträger-Basisband-MIMO-System zur Ausnutzung breitbandiger Übertragungskanäle mit hohem Übersprechen

In der vorliegenden Arbeit wird ein neues Übertragungsverfahren mit dem Namen "Multicarrier enabled Baseband Subsampling Multiple-Input-Multiple-Output" (MBS-MIMO) vorgeschlagen, theoretisch untersucht, evaluiert und praktisch erprobt. Der bekannte hybride Filterbankansatz mit unterabtastenden Analog-digital-Konvertern (ADCs) unter Verwendung der Modulationsart Discrete-Multitone (DMT) in Kombination mit MIMO ermöglicht es, Verkopplungen paralleler Übertragungskanäle und durch Unterabtastung verursachtes Aliasing äquivalent zu betrachten. Daraus ergeben sich Vorteile gegenüber dem Stand der Technik: Da Alias als separater MIMO-Kanal angesehen werden kann, können bekannte MIMO Algorithmen zur Entzerrung und Entkopplung angewendet werden. Die parallel arbeitenden ADCs in den Teilbändern der Filterbank und die Orthogonalität der Subträger im Basisband erlauben eine massive Parallelisierung der Signalverarbeitung, wodurch die Taktraten reduziert werden und die Leistungsaufnahme sinkt. Die Phasen der ADCs zueinander können nahezu beliebig gewählt werden