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At least 289 records · Page 16Linked to original sources
PubMed1990

Medial forebrain bundle of the rat: III. Cytoarchitecture of the rostral (telencephalic) part of the medial forebrain bundle bed nucleus.

The boundaries of the medial forebrain bundle (MFB) of the rat have been presented in previous work on the structure of this fiber system (Nieuwenhuys et al.: J. Comp. Neurol. 206:49-81, '82). Neuronal cell bodies within these outlines constitute the bed nucleus of the MFB. Many fiber components of the MFB appeared to be spatially arranged within the bundle and featured an orderly topography (Veening et al.: J. Comp. Neurol. 206:82-108, '82). As the fibers of the MFB are thought to be a major source of afferents to the bed nucleus (Millhouse: In P.J. Morgane and J. Panksepp (eds): Anatomy of the Hypothalamus, Vol. 1. New York: Marcel Dekker, pp. 221-265, '79), the latter has been subjected in this and the companion study (Geeraedts et al.: J. Comp. Neurol. 294:537-568, '90) to a detailed cytoarchitectonic analysis. This analysis is based on continuous series sectioned in the three conventional planes. On the basis of cytoarchitectonic characteristics, including size and shape, staining intensity, packing density, and spatial orientation of the cell bodies, it was found that the bed nucleus of the MFB as described in the literature is by no means a cytoarchitectonic unit per se. Rather, the neuronal cell population located within the telencephalic stream of the MFB can be parcellated into a number of cellular groups, which partly or entirely belong to more-or-less known basal telencephalic structures. These structures are designated here as the MFB-related areas. They correspond largely to the subcommissural substantia innominata (SIC), the sublenticular substantia innominata (SIL), the nucleus of the diagonal band of Broca, the olfactory tubercle, the magnocellular preoptic nucleus (POMA), the lateral preoptic area (LPOA), and the interstitial nucleus of the stria medullaris (ISM). The complex of the MFB-related areas is surrounded by the following cellular entities: the nucleus accumbens (ACB), the caudatus-putamen region (CPU), the globus pallidus (GP), the bed nucleus of the stria terminalis (BST), the anterior amygdaloid area (AAA), the amygdaloid nuclear complex (A), the medial preoptic area (MPOA) and the anterior hypothalamic area (AHA). Both MFB-related areas and their surroundings have been identified and delimited in this study. This resulted in a new cytoarchitectonic atlas of the rat's basal telencephalon. Our atlas does not only show the relative positions of the above mentioned cellular groups, but also those of their subdivisions.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Signal transduction events mediated by the BDNF receptor gp 145trkB in primary hippocampal pyramidal cell culture.

The trkB gene encodes a tyrosine kinase receptor, gp145trkB, for brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4). To understand the role of gp145trkB in the nervous system, we have investigated its expression in embryonic rat hippocampal pyramidal cell cultures and examined the effects of BDNF on signal transduction in the primary neurons. The expression of trkB transcripts was established by PCR analysis and in situ hybridization. In addition to gp145trkB, the pyramidal neuronal cultures expressed transcripts specific for the NT-3 receptor gp145trkC, but not for the high-affinity NGF receptor gp140trk or for p75LNGFR, a low-affinity receptor for all known members of the NGF family of neurotrophins including the gp145trkB ligands, BDNF and NT-4. The presence of gp145trkB receptors in the primary neuronal cultures was confirmed by immunocytochemical analysis in which > 90% of the cells stained with affinity-purified polyclonal antibodies to gp145trkB. Immunoblots using this antibody revealed a single approximately 140 kDa protein in both adult hippocampus and pyramidal cultures. Addition of recombinant BDNF to these cultures induced the tyrosine phosphorylation of gp145trkB, as determined by antiphosphotyrosine staining of gp145trkB immunoprecipitates. Moreover, BDNF treatment activated the microtubule-associated protein (MAP) kinases, as determined by an increase in MAP2 phosphorylation in vitro. Both the 41 and 44 kDa forms of MAP kinase were activated by BDNF. BDNF also increased c-fos expression in over 90% of the cells. These results indicate that gp145trkB does not require p75LNGFR to form a functional receptor for BDNF in hippocampal pyramidal neurons.

3T3 Cells↗
PubMed1993

Identification and localization of two genes on the chicken Z chromosome: implication of evolutionary conservation of the Z chromosome among avian species.

A cDNA clone containing an insert of about 3.4 kb, pCIREBP, was isolated from the chicken liver cDNA library and identified as a clone for the chicken homologue of iron-responsive element-binding protein (IREBP). The deduced amino acid sequence showed 88% identity with that of the mouse IREBP and 17 out of the 20 active site residues of the pig heart mitochondrial aconitase were conserved. Another cDNA clone, pZOV3, containing an insert of about 4.5 kb was isolated from the chicken ovary cDNA library. This cDNA contained an open reading frame for 327 amino acid residues, whose sequence had partial similarity to two immunoglobulin superfamily proteins; mouse GP-70 and chicken HT7. Fluorescence in situ hybridization using corresponding genomic clones revealed that both genes are localized on the Z chromosome; the ZOV3 gene at the middle of the short arm and the IREBP gene at the boundary of heterochromatin on the long arm. Southern blot hybridization to male and female genomic DNA preparations from six species representing five avian genera suggested that these two genes are Z-linked in all the species tested.

Amino Acid Sequence↗
PubMed1998

Genetic analysis of the UL 15 gene locus for the putative terminase of herpes simplex virus type 1.

The herpes simplex virus (HSV-1) UL15 gene encodes one of the six viral gene products required for viral DNA cleavage and packaging. UL15 is a spliced gene and encodes two separately translated proteins, UL15 and UL15.5. Sequence analysis reveals that UL15 shares homology with gp 17, the large catalytic subunit of the bacteriophage T4 terminase, a protein which cleaves the polymeric T4 DNA into monomers. Both proteins contain a putative ATP binding motif known as the Walker A and B boxes. In this report, immunofluorescence was used to show that UL15 localizes to the nucleus in the absence of any other viral proteins; this indicates that UL15 contains its own nuclear localization signal. In addition, we found that UL15 colocalizes with replication compartments at early times (6 h postinfection). Since, at this time, preformed capsids as well as other cleavage and packaging proteins are also recruited to replication compartments, it seems likely that cleavage and packaging occurs in the same compartments in which DNA synthesis occurs. Also in this report, we have investigated UL15.5, the N-terminally truncated gene product of the UL15 open reading frame (ORF). The start codon has been mapped to Met443 within the UL15 ORF. Furthermore, we have shown that plasmids containing a UL15.5 knockout mutation still complement the growth of UL15 insertion mutant viruses, indicating that UL15.5 is not required for viral growth in cell culture. Last, we constructed a UL15 mutant, UL15C(G263A), in which the invariant Gly263 in the Walker box A of the ATP binding motif (GKT) was substituted with an alanine. We show that the mutant gene fails to support the growth of UL15 insertion mutant viruses, indicating that the putative ATP binding motif of UL15 is indispensable for its function.

Animals↗
PubMed2005

The human antibody repertoire specific for rabies virus glycoprotein as selected from immune libraries.

Antibody phage display technology was used to identify human monoclonal antibodies that neutralize rabies virus (RV). A phage repertoire was constructed using antibody genes harvested from the blood of vaccinated donors. Selections using this repertoire and three different antigen formats of the RV glycoprotein (gp) resulted in the identification of 147 unique antibody fragments specific for the RV gp. Analysis of the DNA sequences of these antibodies demonstrated a large variation in the heavy- and light-chain germ-line gene usage, suggesting that a broad antibody repertoire was selected. The single-chain variable fragment (scFv) antibodies were tested in vitro for RV neutralization, resulting in 39 specificities that neutralize the virus. Of the scFv clones, 21 were converted into full-length human IgG(1) format. Analysis of viral escape variants and binding competition experiments indicated that the majority of the neutralizing antibodies are directed against antigenic site III of the RV gp. The obtained specificities expand the set of human anti-RV antibodies eligible for inclusion in an antibody cocktail aimed for use in rabies post-exposure prophylaxis.

Amino Acid Sequence↗
PubMed1989

Glycophorin expression in murine erythroleukaemia cells.

We have identified mature and putative precursor forms of glycophorins expressed in a virus-transformed murine erythroleukaemia (MEL) cell line and compared them with their normal erythroblast counterparts. The following differences were found: (1) the two major MEL cell glycophorins (apparent Mr values 29-30 and 43(x10(3] have greater mobility on polyacrylamide gels than their normal gp-3 and gp-2 counterparts, due at least in part to differences in their oligosaccharide sidechains; (2) MEL cell gp-3 consists of two discrete proteins; and (3) there are more potential glycophorin precursors in MEL cells than in normal mouse erythroblasts. Four proteins, with apparent Mr values of 21, 23, 26 and 27(x10(3], have tentatively been identified as glycophorin precursors, based on the following findings: (1) they are immunologically related to the glycophorins; and (2) their synthesis was induced by dimethyl sulphoxide coincidentally with that of gp-3 and gp-2. They do not appear to be glycoproteins, as evidenced by their lack of incorporation of [3H]galactose, [3H]glucosamine or [3H]mannose. In contrast, gp-3 and gp-2 incorporated [3H]galactose and [3H]glucosamine but not [3H]mannose. Partial characterization of the glycan moieties of MEL cell glycophorins indicates that they consist mostly of tri- and tetrasaccharides, with no indication of any N-linked chains. Hence, the glycans of MEL cell glycophorins are mostly (if not all) O-linked. Furthermore, treatment with N-glycanase did not change their electrophoretic mobility on polyacrylamide gels. MEL cell glycophorins were also shown to be modified by phosphoryl and fatty acyl groups.

Animals↗
PubMed2002

New approach to pharmacophore mapping and QSAR analysis using inductive logic programming. Application to thermolysin inhibitors and glycogen phosphorylase B inhibitors.

A key problem in QSAR is the selection of appropriate descriptors to form accurate regression equations for the compounds under study. Inductive logic programming (ILP) algorithms are a class of machine-learning algorithms that have been successfully applied to a number of SAR problems. Unlike other QSAR methods, which use attributes to describe chemical structure, ILP uses relations. This gives ILP the advantages of not requiring explicit superimposition of individual compounds in a dataset, of dealing naturally with multiple conformations, and of using a language much closer to that used normally by chemists. We unify ILP and standard regression techniques to give a QSAR method that has the strength of ILP at describing steric structure with the familiarity and power of regression methods. Complex pharmacophores, correlating with activity, were identified and used as new indicator variables, along with the comparative molecular field analysis (CoMFA) prediction, to form predictive regression equations. We compared the formation of 3D-QSARs using standard CoMFA with the use of ILP on the well-studied thermolysin zinc protease inhibitor dataset and a glycogen phosphorylase inhibitor dataset. In each case the addition of ILP variables produced statistically better results (P < 0.01 for thermolysin and P < 0.05 for GP datasets) than the CoMFA analysis. Moreover, the new ILP variables were not found to increase the complexity of the final QSAR equations and gave possible insight into the binding mechanism of the ligand-protein complex under study.

Algorithms↗
PubMed1992

Recognition of compartmentalized intracellular analogs of glycoprotein H of human cytomegalovirus.

Infected cell proteins immunoprecipitated from human cytomegalovirus (HCMV)-infected fibroblasts with glycoprotein H (gH)-specific conformation-dependent monoclonal antibody (mab 14-4 b) were found to consist of three components of 86 kDa, 89 kDa, and 125 kDa (gp 86, 89, and 125). Affinity purified antibodies from human convalescent serum reactive with an NH2-terminal epitope of gH recognized three polypeptides of comparable size in immunoblots, suggesting antigenic relatedness of these three components of the gH-complex. Using subcellular fractions for immunoblotting, gp 86 was identified as an endoglycosidase H (endo H)-sensitive gH-form present in the nuclear fraction whereas gp 89 and gp 125 were endo H-resistant and present in the membrane fraction or in virions. Incomplete endo H-digestion suggested that four of six predicted N-glycosylation sites of the gH molecule were occupied by carbohydrate side chains. Analysis under nonreducing conditions revealed that the compartmentalized as well as virion-associated gH analogs form high molecular weight complexes. The relation of the recognized gH analogs to the processing pathway of gH is discussed.

Cells, Cultured↗
PubMed2002

Molecular modeling of the seven tandem leucine-rich repeats within the ligand-binding region of platelet glycoprotein Ib alpha.

Platelet glycoprotein (GP)Ib-IX-V mediates von Willebrand Factor (vWF)-dependent adhesion to vascular subendothelium at high shear in (patho)physiological thrombus formation. The ligand-binding domain of GPIb-IX-V is within the N-terminal 282 residues of GPIb alpha, that contains seven tandem leucine-rich repeats (Leu36-Ala200). Repeats 2-4 are critical for vWF binding. In this study, we have built molecular models of the seven leucine-rich repeats of human, canine and mouse GPIb alpha, providing novel insights into the species-specific interaction between human vWF and its receptor. Interestingly, a major difference between the models was a large negatively charged patch on the concave face of human, but not canine, repeats 2-4. In addition, five individual mutations within the leucine-rich repeats of GPIb alpha associated with the bleeding disorder Bernard-Soulier syndrome, that result in dysfunctional vWF binding, were mapped to the model of human GPIb alpha. This provides the basis for relating these genetic lesions to abnormal function of the receptor.

Amino Acid Sequence↗
PubMed1991

Genes newly identified as regulated by glucocorticoids in murine thymocytes.

Glucocorticoids induce dramatic biochemical and morphological changes in lymphocytes through an unknown process that requires RNA and protein synthesis. In order to identify genes involved in this response, we previously isolated 11 cDNA clones from the murine WEHI-7TG thymoma cell line that correspond to mRNAs induced by glucocorticoids. We now report the isolation of two new cDNA clones whose gene expression is regulated by glucocorticoids in WEHI-7TG cells. We further characterize the two new cDNA clones, as well as those described previously, by examining the response of each of the corresponding mRNAs to glucocorticoids in murine thymocytes. With the exception of two, all cDNAs correspond to genes that are induced by glucocorticoids in murine thymocytes within 4 h of treatment. We previously identified two of the cDNAs as the mouse VL30 retrovirus-like element and the mouse homolog of chondroitin sulfate proteoglycan core protein. We have now identified four additional cDNA clones that correspond to the genes for calmodulin, mitochondrial phosphate carrier protein, immunoglobulin (Ig)-related glycoprotein (GP-70), and the 70 kilodalton autoantigen for Lupus and Graves diseases. Two other cDNA clones represent previously undescribed genes: one shares a high similarity to known sequences for the family of G-protein-coupled receptors and the other to a human placental-specific protein, PP11. Another cDNA appears to contain sequences for an unknown gene and the remnants of a mouse transposon. ETn. The remaining clones represent new, unidentified genes induced by glucocorticoids in murine thymocytes and in the WEHI-7TG cell line.

Animals↗
PubMed2001

Receptor engagement by viral interleukin-6 encoded by Kaposi sarcoma-associated herpesvirus.

Receptor usage by viral interleukin-6 (vIL-6), a virokine encoded by Kaposi sarcoma- associated herpesvirus, is an issue of controversy. Recently, the crystal structure of vIL-6 identified vIL-6 sites II and III as directly binding to glycoprotein (gp)130, the common signal transducer for the IL-6 family of cytokines. Site I of vIL-6, however, comprising the outward helical face of vIL-6, where human IL-6 (hIL-6) would interact with the specific alpha-chain IL-6 receptor (IL-6R), is accessible and not occupied by gp130. This study examined whether this unused vIL-6 surface is available for IL-6R binding. By enzyme-linked immunosorbent assay, vIL-6 bound to soluble gp130 (sgp130) but not to soluble IL-6R (sIL-6R). Using plasmon surface resonance, vIL-6 bound to sgp130 with a dissociation constant of 2.5 microM, corresponding to 1000-fold lower affinity than that of hIL-6/sIL-6R complex for gp130. sIL-6R neither bound to vIL-6 nor affected vIL-6 binding to gp130. In bioassays, vIL-6 activity was neutralized by 4 monoclonal antibodies (mAbs) recognizing a domain within vIL-6 site I, mapped to the C-terminal part of the AB-loop and the beginning of helix B. The homologous region in hIL-6 participates in site I binding to IL-6R. In addition, binding of vIL-6 to sgp130 was interfered with specifically by the 4 neutralizing anti-vIL-6 mAbs. Based on the vIL-6 crystal structure, the vIL-6 neutralizing mAbs map outside the binding interface to gp130, suggesting that they either produce allosteric changes or block necessary conformational changes in vIL-6 preceding its binding to gp130. These results document that vIL-6 does not bind IL-6R and suggest that conformational change may be critical to vIL-6 function.

Allosteric Regulation↗
PubMed1994

Presentation of native epitopes in the V1/V2 and V3 regions of human immunodeficiency virus type 1 gp120 by fusion glycoproteins containing isolated gp120 domains.

The immune response to viral glycoproteins is often directed against conformation- and/or glycosylation-dependent structures; synthetic peptides and bacterially expressed proteins are inadequate probes for the mapping of such epitopes. This report describes a retroviral vector system that presents such native epitopes on chimeric glycoproteins in which protein fragments of interest are fused to the C terminus of the N-terminal domain of the murine leukemia virus surface protein, gp70. The system was used to express two disulfide-bonded domains from gp120, the surface protein of human immunodeficiency virus type 1 (HIV-1), that include potent neutralization epitopes. The resulting fusion glycoproteins were synthesized at high levels and were efficiently transported and secreted. A fusion protein containing the HXB2 V1/V2 domain was recognized by an HIVIIIB-infected patient serum as well as by 17 of 36 HIV-1 seropositive hemophiliac, homosexual male and intravenous drug user patient sera. Many of these HIV+ human sera reacted with V1/V2 domains from several HIV-1 clones expressed in fusion glycoproteins, indicating the presence of cross-reactive antibodies against epitopes in the V1/V2 domain. Recognition of gp(1-263):V1/V2HXB2 by the HIVIIIB-infected human patient serum was largely blocked by synthetic peptides matching V1 but not V2 sequences, while recognition of this construct by a broadly cross-reactive hemophiliac patient serum was not blocked by individual V1 or V2 peptides or by mixtures of these peptides. A construct containing the V3 domain of the IIIB strain of HIV-1, gp(1-263):V3HXB2, was recognized by sera from a human and a chimpanzee that had been infected by HIVIIIB but not by sera from hemophiliac patients who had been infected with HIV-1 of MN-like V3 serotype. The reactive sera had significantly higher titers when assayed against gp(1-263):V3HXB2 than when assayed against matching V3 peptides. Immunoprecipitation of this fusion glycoprotein by the human serum was only partially blocked by V3 peptide, indicating that this infected individual produced antibodies against epitopes in V3 that were expressed on the fusion glycoprotein but not by synthetic peptides. These data demonstrated that the chimeric glycoproteins described here effectively present native epitopes present in the V1/V2 and V3 domains of gp120 and provide efficient methods for detection of antibodies directed against native epitopes in these regions and for characterization of such epitopes.

3T3 Cells↗
PubMed1996

Complementation Mapping in Microcell Hybrids: Localization of XRCC4 to 5q15-q21

Microcell-mediated chromosome transfer (MMCT) offers a unique method for introducing tagged individual human chromosomes from mouse/human monochromosomal hybrids into cell lines displaying recessive mutant phenotypes. Functional analysis of the resultant microcell hybrids bearing different tagged individual human chromosomes permits identification of the complementing chromosome. Using this approach, a number of human DNA repair genes that complement DNA repair defects in Xeroderma pigmentosum, Ataxia telangiectasia, Bloom's syndrome, and rodent mutant cells have been mapped to specific chromosomes. In this paper, we present experiments performed to map a DNA double-strand break (dsb) repair gene, XRCC4, to human chromosome 5q15-q21. The introduction of human chromosome 5 into Chinese hamster mutant XR-1 cells corrected their X-ray sensitivity and DNA dsb repair deficiency. Loss of chromosome 5 and concomitant reversion to the radiosensitive phenotype confirmed the presence of XRCC4 on this chromosome. Analysis of DNA markers in radiation-resistant and -sensitive clones bearing different segments of chromosome 5 placed this gene in the region 5q15-q21. These studies demonstrate the application of MMCT technology to the genetic analysis of mutations that escape other experimental approaches.

Journal Article↗
PubMed1989

A multigene deletion in the human IGH constant region locus involves highly homologous hot spots of recombination.

A simultaneous absence of the IgG1, IgG2, IgG4, and IgA1 immunoglobulins (Ig) was unambiguously demonstrated in six healthy individuals of two different families (family HASS and family TOU). These individuals were shown to be homozygous for a large deletion in the immunoglobulin heavy chain constant region locus. This deletion, which encompasses the G1-EP1-A1-GP-G2-G4 genes, allowed us to predict an order for the IgCH genes and to localize GP between A1 and G2. In this paper, we study the deletion-recombination point in the IGH locus of individual EZZ from the TOU family. We show that the distance between the G3 and the E genes on the EZZ recombinant chromosome is 24.7 kb and that the multigene deletion in the IgCH locus involves two highly homologous regions (hsg3 and hsg4) which are hot spots of recombination, outside of the switch sequences.

Base Sequence↗
PubMed1997

Molecular characterization of the gene for human cartilage gp-39 (CHI3L1), a member of the chitinase protein family and marker for late stages of macrophage differentiation.

We have previously reported that the expression of HC gp-39, a 39-kDa secretory glycoprotein and member of the chitinase protein family, is associated with late stages of monocyte to macrophage maturation. To allow further investigations of its unique expression pattern and to facilitate studies on the regulation of this "marker gene," we characterized the genomic organization of the HC gp-39 gene (HGMW-approved symbol CHI3L1) and cloned its 5'-proximal promotor region. The gene is composed of 10 exons distributed over an 8-kb region. Two transcriptional initiation sites located 82 and 126 nucleotides upstream of the ATG start codon were identified using primer extension and S1 nuclease protection assays. We sequenced 1.3 kb of the 5'-flanking region and identified a variety of putative regulatory elements.

Adipokines↗
PubMed2001

Genomic and phylogenetic analysis of the human CD1 and HLA class I multicopy genes.

The human CD1 proteins belong to a lipid-glycolipid antigen-presenting gene family and are related in structure and function to the MHC class I molecules. Previous mapping and DNA hybridization studies have shown that five linked genes located within a cluster on human chromosome 1q22-23 encode the CD1 protein family. We have analyzed the complete genomic sequence of the human CD1 gene cluster and found that the five active genes are distributed over 175,600 nucleotides and separated by four expanded intervening genomic regions (IGRs) ranging in length between 20 and 68 kb. The IGRs are composed mostly of retroelements including five full-length L1 PA sequences and various pseudogenes. Some L1 sequences have acted as receptors for other subtypes or families of retroelements. Alu molecular clocks that have evolved during primate history are found distributed within the HLA class I duplicated segments (duplicons) but not within the duplicons of CD1. Phylogeny of the alpha3 domain of the class I-like superfamily of proteins shows that the CD1 cluster is well separated from HLA class I by a number of superfamily members including MIC (PERB11), HFE, Zn-alpha2-GP, FcRn, and MR1. Phylogenetically, the human CD1 sequences are interspersed by CD1 sequences from other mammalian species, whereas the human HLA class I sequences cluster together and are separated from the other mammalian sequences. Genomic and phylogenetic analyses support the view that the human CD1 gene copies were duplicated prior to the evolution of primates and the bulk of the HLA class I genes found in humans. In contrast to the HLA class I genomic structure, the human CD1 duplicons are smaller in size, they lack Alu clocks, and they are interrupted by IGRs at least 4 to 14 times longer than the CD1 genes themselves. The IGRs seem to have been created as "buffer zones" to protect the CD1 genes from disruption by transposable elements.

Antigens, CD1↗
PubMed2002

Magnetic resonance imaging-based morphometry and landmark correlation of basal ganglia nuclei.

The two principle targets for deep brain stimulation or lesioning in patients with Parkinson's disease, the subthalamic nucleus (STN) and the globus pallidus internus (GPi), reveal a high degree of individual variability which is relevant to the planning of stereotactic operations. Both nuclei can clearly be delineated in T2WI spin echo MRI which was acquired under stereotactic conditions in general anesthesia before surgery. Such images of 35 patients served for retrospective morphometric analysis of different basal ganglia nuclei (STN, GP, red nucleus, and substantia nigra) and several anatomical landmarks (anterior and posterior commissure, maximum width of third ventricle, brain length and width). The average AC-PC distance was 25.74 mm (range 21 to 29 mm) and is in agreement with previous studies. On average, the center of the STN was located 12.65 mm (+/-1.3) lateral from the midline as determined 3 mm ventral to the intercommissural plane. The average width of the third ventricle was 7.05 mm (+/-2.41). The width of the third ventricle correlated with the laterality of the STN (r(right)=.78; r(left)=.83) and GP (r(right)=.76; r(left)=.68). Although to a lesser extent, significant correlations were also observed between the laterality of the STN and brain width, improving prediction of STN laterality by multiple linear regression analysis (r(right)=.82; r(left)=.87). Similarly, the laterality of GP correlated with brain width. In addition, gender-specific differences were detected. The STN and GP was located farther lateral in males which may be due to overall brain anatomy as gender-specific differences were also observed for brain width and length and AC-PC distance. MRI-based in vivo-localization of different basal ganglia nuclei extend statistical information from common histological brain atlases which are based on a limited number of brains. The correlations observed between different basal ganglia nuclei, i.e. the STN and GPi, and anatomical landmarks may be useful for surgical planning.

Adult↗
PubMed1993

The nuclear magnetic resonance solution structure of flavoridin, an antagonist of the platelet GP IIb-IIIa receptor.

The snake venom protein flavoridin, a polypeptide of 70 amino acid residues, is a potent inhibitor of blood platelet aggregation. It binds to cell-surface integrin receptors such as the fibrinogen receptor glycoprotein IIb/IIIa. The inhibitory properties of flavoridin have been attributed to the tripeptide segment Arg-Gly-Asp (residues 49 to 51). This paper describes the determination of the three-dimensional structure of flavoridin in aqueous solution based on two-dimensional nuclear magnetic resonance spectroscopy. A family of 18 conformers was selected to characterize the solution structure. The molecule comprises two structural domains, an N-terminal unit extending from residues 1 to 25, and a C-terminal unit from residues 26 to 70. Whereas the mutual spatial orientation of these regions is not well defined, each one is well organized within itself. The segment 26 to 70, which is homologous to the sequence of the snake toxins echistatin and eristostatin, shows an average value of 1.0 A for the root-mean-square deviations of the backbone atoms among the 18 conformers. The structure of flavoridin consists essentially of non-repetitive elements such as tight turns and loops, whose location and conformation are characterized in this paper. With the exception of two short regions of antiparallel beta-sheet, no classic element of protein secondary structure is present. The six disulphide bridges, which have been mapped by applying a novel computational strategy (see accompanying paper), are the dominant organizational feature of the polypeptide fold of flavoridin. Two of the bridges are located in the N-terminal domain, three in the C-terminal domain and one connects the two structural units. The mobile RGD recognition sequence for integrins is located peripheral to the core region of the C-terminal domain at the most exposed end of a nine residue loop structure, which is attached to a short beta-sheet. The C terminus is close to this loop structure.

Amino Acid Sequence↗