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Biomedical subjects

A Rau

Publications and source records attributed to A Rau.

7 recordsLinked to original sources

Tectorin mRNA expression is spatially and temporally restricted during mouse inner ear development.

The tectorial and otolithic membranes are extracellular matrices that cover the sensory epithelia of the inner ear. They are required for mechanotransduction and may influence hair-cell development. The mRNA expression patterns for two major glycoproteins of these matrices, alpha- and beta-tectorin, were examined during mouse inner ear development to determine when and where these proteins are produced relative to hair cells and whether tectorin production is continuous or transient. Using in situ hybridisation, alpha- and beta-tectorin mRNAs are first detected in the basal end of the cochlea at embryonic day (E) 12.5, and the distinct patterns observed for each tectorin mRNA in the neonate become visible by E14.5. The neonatal expression patterns indicate that some cell types in the cochlea express both alpha- and beta-tectorin mRNAs, while other cells only express one tectorin mRNA. Although expressed early in development, alpha- and beta-tectorin mRNAs cannot be detected in the cochlea by postnatal day (P) 22. In the saccule and utricle, alpha-tectorin mRNA is detected at E12.5, but beta-tectorin mRNA is not observed until E14.5. Expression of alpha-tectorin mRNA ceases after P15, whereas beta-tectorin mRNA expression continues within the striolar region of the utricle until at least P150. The results show alpha- and beta-tectorin mRNAs are expressed during the early stages of inner ear development, prior to or concomitant with hair-cell differentiation, and before the appearance of hair bundles. The expression patterns suggest different cell types contribute to the formation of the various regions of the tectorial membrane. Although tectorin mRNAs are only expressed transiently during cochlear development, beta-tectorin mRNA is continuously expressed within the striolar region of the utricle.

Animals↗

Spontaneous perforation of the hepatic duct in adults.

BACKGROUND: Nontraumatic perforations of the extrahepatic biliary ductal system are a rare albeit recognized occurrence in the cystic duct, choledochus and main hepatic duct; the latter appears to be the rarest. METHODS: Recent experience with such a case prompted a thorough review of 26 similar cases previously reported. RESULTS: It appears that obstruction of the biliary tract by gallstones results in raised intraductal pressure leading to dilatation of the biliary tree, subsequent stasis and infection, causing ascending cholangitis and thrombosis of intramural vessels, leading to necrosis and perforation of the duct wall. Most patients present with an acute abdomen and are operated upon. CONCLUSIONS: The goals of operation, which should be tailored to the individual patient, are to stop the bile leak, cure choledocholithiasis and cholangitis and reconstruct the bile duct.

Abdomen, Acute↗

The mouse tectorins. Modular matrix proteins of the inner ear homologous to components of the sperm-egg adhesion system.

The cDNA and derived amino acid sequences for the two major non-collagenous proteins of the mouse tectorial membrane, alpha- and beta-tectorin, are presented. The cDNA for alpha-tectorin predicts a protein of 239,034 Da with 33 potential N-glycosylation sites, and that of beta-tectorin a smaller protein of 36,074 Da with 4 consensus N-glycosylation sites. Southern and Northern blot analysis indicate alpha- and beta-tectorin are single copy genes only expressed in the inner ear, and in situ hybridization shows they are expressed by cells both in and surrounding the mechanosensory epithelia. Both sequences terminate with a hydrophobic COOH terminus preceded by a potential endoproteinase cleavage site suggesting the tectorins are synthesized as glycosylphosphatidylinositol-linked, membrane bound precursors, targeted to the apical surface of the inner ear epithelia by the lipid and proteolytically released into the extracellular compartment. The mouse beta-tectorin sequence contains a single zona pellucida domain, whereas alpha-tectorin is composed of three distinct modules: an NH2-terminal region similar to part of the entactin G1 domain, a large central segment with three full and two partial von Willebrand factor type D repeats, and a carboxyl-terminal region which, like beta-tectorin, contains a single zona pellucida domain. The central, high molecular mass region of alpha-tectorin containing the von Willebrand factor type D repeats has homology with zonadhesin, a sperm membrane protein that binds to the zona pellucida. These results indicate the two major non-collagenous proteins of the tectorial membrane are similar to components of the sperm-egg adhesion system, and, as such may interact in the same manner.

Alternative Splicing↗

[The modified Magill forceps].

The Magill forceps are used for nasotracheal intubation, endotracheal suctioning, passing gastric tubes, placement of tampons in the nasopharynx and extraction of foreign material from the pharynx. There are several disadvantages of the standard Magill forceps; however: the danger of cuff perforation, the necessity of readjusting the forceps when placing a tube or catheter, and the risk of injury to the mucous membrane. For these reasons the standard Magill forceps have been modified: the jaws of the forceps have been changed to give curved atraumatic parts without any serrations or sharp edges. RESULTS. The resulting benefits are as follows: Reduced risk of injuring the mucous membrane and perforating the cuff. Tubes and catheter are safely guided between the semiround jaws, making it unnecessary to open the forceps repeatedly to advance the tube. Tampons being placed in the throat no longer get caught between the serrations, and even small foreign objects can easily be extracted from the pharynx.

Anesthesiology↗

Primordial transport of sugars and amino acids via Schiff bases.

Experimental support is given for a model concerning the origin of a primordial transport system. The model is based on the facilitated diffusion of amino acids stimulated by aliphatic aldehyde carriers and sugars stimulated by aliphatic amine carriers. The lipid-soluble diffusing species is the Schiff base. The possible role of this simple transport system in the origin of an early protocell is discussed.

Amino Acids↗