Identification of neural genes using Xenopus DNA microarrays.

To isolate novel genes regulating neural induction, we used a DNA microarray approach. As neural induction is thought to occur by means of the inhibition of bone morphogenetic protein (BMP) signaling, BMP signaling was inhibited in ectodermal cells by overexpression of a dominant-negative receptor. RNAs were isolated from control animal cap explants and from dominant-negative BMP receptor expressing animal caps and subjected to a microarray experiment using newly generated high-density Xenopus DNA microarray chips representing over 17,000 unigenes. We have identified 77 genes that are induced in animal caps after inhibition of BMP signaling, and all of these genes were subjected to whole-mount in situ hybridization analysis. Thirty-two genes showed specific expression in neural tissues. Of the 32, 14 genes have never been linked to neural induction. Two genes that are highly induced by BMP inhibition are inhibitors of Wnt signaling, suggesting that a key step in neural induction is to produce Wnt antagonists to promote anterior neural plate development. Our current analysis also proves that a microarray approach is useful in identifying novel candidate factors involved in neural induction and patterning.     

A case of 49,XXXXX in which the extra X chromosomes were maternal in origin

This report describes an 11 month old female baby with features of pentasomy X. A molecular and cytogenetic evaluation revealed that her karyotype was 49,XXXXX and her extra X chromosomes were of maternal origin. She has muscular hypotonia, mental retardation, a cleft palate, mild hydrocephalus as a result of dilatation of both lateral ventricles, hyperextensible elbow joints, proximal radioulnar synostosis, clinodactyly of the fifth finger, valgus of the feet, and small hands and feet. In addition, she has a persistent pupillary membrane and congenital chorioretinal atrophy. The pathogenesis of pentasomy X is not clear at present, but it is thought to be caused by successive maternal non-dysjunctions.     

Thyroglobulin synthesis of oxyphilic cells in various types of neoplastic and autoimmune thyroid diseases.

To determine the content of thyroglobulin in oxyphilic cells of the thyroid, which have been considered as non-thyroglobulin producing cells, the degree of stainability of the various oxyphilic cells for thyroglobulin was compared with that of non-oxyphilic follicular cells in either same or different lesion. A total of 13 oxyphilic lesions, including three follicular adenomas containing oxyphilic cell nodules, four pure oxyphilic cell adenomas, and six Hashimoto's thyroiditis were compared with 16 of non-oxyphilic lesions such as, seven follicular adenomas, four chronic lymphocytic thyroiditis, and five Graves' disease. Many oxyphilic cells stained positively for thyroglobulin regardless of their morphologic variation, but less intensely than the usual follicular cells in follicular adenomas, chronic lymphocytic thyroiditis, and Graves' disease. The stainability of oxyphilic cells for thyroglogulin did not show any significant correlation with morphologic features, whereas in follicular adenomas, the non-oxyphilic follicular cells forming microfollicles stained less strongly for thyroglobulin than the same cells lining large mature follicles in a reproducible way. With above findings, we concluded that oxyphilic cells maintain the functional activity in terms of thyroglobulin synthesis, although the content of the thyroglobulin is less than that of non-oxyphilic colloid forming follicular cells.     

Hepatocyte attachment onto thermosensitive poly(N-isopropylacrylamide-co-N-p-vinylbenzyl-O-beta-D-galactopyranosyl-(1 --> 4)-D-gluconamide)

Temperature sensitive poly(N-isopropylacrylamide) (PIPAAM) was incorporated into hepatocyte-recognizable poly[N-p-vinylbenzyl-O-beta-D-galactopyranosyl-(1 --> 4)-D-gluconamide] (PVLA) for thermal modulating of hepatocyte attachment. The copolymer, poly(N-isopropylacrylamide-co-N-p-vinylbenzyl-O-beta-D-galactopyranosyl-(1 --> 4)-D-gluconamide) (abbreviated as [P(IPAAM-co-VLA)] (PIPAAM/PVLA = 9/1 in mol%) exhibited lower critical solution temperature (LCST) at 34 degrees C and also showed very good hepatocytes-recognizablility through the specific interaction between asialoglycoprotein receptors on the cell surfaces and galactose moiety of the copolymer. The cells attached on this copolymer were easily detached by lowering the temperature below the LCST of the copolymer. Morphological damage of the detached cell was not observed.     

Interaction between poly(L-lysine) and sulfated poly(vinyl alcohol)

Ionic polymer-polymer interaction was studied in aqueous solution for poly(L -lysine) (PLL) and sulfated poly(vinyl alcohol) (PVS) as functions of pH, the degree of sulfation, the functional unit mole ratio of the two polymers and temperature by means of circular dichroism and viscosity measurements. In all the cases studied, strong inter-polymer complexes were formed at the functional unit mole ratio (VS)/(LL) higher than 1. Although PLL itself is well known to take the α-helical conformation at such a high pH as 11, the PLL conformation in the PLL/PVS complexes did not depend on pH but on the degree of sulfation: at room temperature, PLL took random coil conformation in PLL/PVS-25 (25: degree of sulfation in mole-%) and PLL/PVS-30, and the α-helical conformation (helicity of 70%) in PLL/PVS-46 and PLL/PVS-95. Models for the complex structures are postulated. Methanesulfonic acid did not influence the conformational transition of PLL, supporting that a polymer effect took place in the complex formation between PLL and PVS. Thermal effect on the PLL conformation in the complex is also discussed.     

Representation of the body in the lateral striatum of the freely moving rat: single neurons related to licking

This study examined the relationship of single-neuron activity (n = 739), recorded from the lateral striatum of freely moving rats, to oral movements involved in licking single drops of liquid. Certain neurons (n = 74) fired specifically in relation to licking. Their firing rates increased during licking, but remained near zero in the absence of licking, throughout a full sensorimotor examination of the remainder of the orofacial area and all other body parts. Another category of neurons (n = 17) fired during licking but also fired in the absence of licking, during one or more other orofacial sensorimotor function(s). Lick-related neurons were located in the lateral striatum, throughout the entire anterior-posterior range studied (from +1.5 to -1.5 mm anterior-posterior, A-P, bregma = 0). Summed over the full A–P range, they were located significantly ventral to representations of the trunk and limbs. These findings extend the characterization of the somatotopic organization exhibited by lateral striatal neurons in the rat, to include representation of oral functions, consistent with converging evidence regarding the functional organization of the striatum.     

Linkage and linkage disequilibrium in chromosome band 1p36 in American Chaldeans with inflammatory bowel disease

The idiopathic inflammatory bowel diseases (IBDs), consisting of Crohn's disease and ulcerative colitis, are complex genetic disorders involving chronic inflammation of the intestines. Multiple genetic loci have been implicated through genome-wide searches, but refinement of localization sufficient to undertake positional cloning efforts has been problematic. This difficulty can be obviated through identification of ancestrally shared regions in genetic isolates, such as the Chaldean population, a Roman Catholic group from Iraq. We analyzed four multiply affected American Chaldean families with inflammatory bowel disease not known to be related. We observed evidence for linkage and linkage disequilibrium in precisely the same region of chromosome band 1p36 reported previously in an outbred population. Maximal evidence for linkage was observed near D1S1597 by multipoint analysis (MLOD = 3.01, P = 6.1 x 10(-5)). A shared haplotype (D1S507 to D1S1628) was observed over 27 cM between two families. There was homozygous sharing of a 5 cM portion of that haplotype in one family and over a <1 cM region in the second family. Homozygous sharing of this haplotype near D1S2697 and D1S3669 was observed in one individual in a third multiply affected family, with heterozygous sharing in a fourth family. Linkage in outbred families as well as in this genetic isolate indicates that a pathophysiologically crucial IBD susceptibility gene is located in 1p36. These findings provide a unique opportunity to refine the localization and identify a major susceptibility gene for a complex genetic disorder.