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C Dean

Publications and source records attributed to C Dean.

At least 109 records · Page 6Linked to original sources
PubMed1996

Isolation and mapping of a new set of 129 RFLP markers in Arabidopsis thaliana using recombinant inbred lines.

A new collection of 129 Arabidopsis thaliana RFLP markers has been established based upon DNA fragments cloned in the pUC119 plasmid vector and insert end sequences of P1 clones. Dominant/null alleles affecting low-copy number sequences account for nine of the mapped polymorphisms, suggesting that deletions are not rare in A. thaliana. Recombinant inbred (RI) lines were used for mapping these marker loci. RI line-based mapping allows integration of this set of markers with markers previously reported as well as with any markers mapped in the future using this replenishable mapping resource. These markers are useful for map-based gene isolation and genome physical mapping in A. thaliana as well as studies of chromosome colinearity (synteny) with related species.

Arabidopsis↗
PubMed1996

Detailed description of four YAC contigs representing 17 Mb of chromosome 4 of Arabidopsis thaliana ecotype Columbia.

The detailed arrangement of 563 YAC clones comprising four contigs covering approximately 17 Mbp of chromosome 4 is presented. YAC clones were positioned relative to each other and to markers by taking into account marker and end fragment hybridization data and the sizes of all YAC clones. This analysis made it possible to estimate physical distances between the majority of chromosome 4 markers. It also identified a relatively large number of YAC clones containing chimaeric inserts. The YAC contig map of the Columbia ecotype presents an important resource for map-based cloning experiments, rapid mapping of DNA sequences and large-scale genomic sequencing programs.

Arabidopsis↗
PubMed1996

Use of Ac as an insertional mutagen in Arabidopsis.

A pilot-scale transposon mutagenesis experiment using a modified autonomous Activator (Ac) element, Ac delta Nael, was carried out in Arabidopsis thaliana. Four different transformants carrying Ac elements in different and defined genomic locations were used to generate 1000 plants carrying approximately 500 independent germinal transposition events. These plants were then selfed and the 1000 families screened in tissue culture and soil for phenotypic mutants. Fifty different families segregated mutations in their progeny. Preliminary Southern blot analysis of 29 families which segregated mutant progeny, showed that 28 had a transposed Ac. Six of the families were further tested for linkage between the transposed Ac and the mutant phenotype, and instability of the putatively tagged locus. Two of the mutants were shown to be tagged as they were tightly linked to a transposed Ac, and somatic and germinal reversion was associated with loss of Ac. One other mutant locus was shown to be closely linked to a transposed Ac, and therefore was likely to be tagged. The remaining three mutations were not tagged as they were not linked to a transposed Ac. In two of the tagged mutants Ac had transposed to closely linked sites, while in a third mutant the co-segregating Ac had transposed to a site which was not tightly linked to the donor T-DNA. Multiple insertions into the DIF1 locus were found, due to the preferential transposition of Ac to a linked site.

Arabidopsis↗
PubMed1996

Changes in newspaper coverage of cardiovascular health issues in conjunction with a community-based intervention.

Numerous community-based prevention projects, with significant media components, have been conducted over the past decade. Multiple evaluation strategies have been used to document the effectiveness of these interventions, including intermediate measures of community impact such as assessment of media coverage. As part of the evaluation of a community-based intervention (the Bootheel Heart Health Project), dissemination of information on cardiovascular disease (CVD) was measured through a media content analysis of newspapers. Data were analyzed from 23 newspapers in six rural counties in southeastern Missouri for the period October 1988 through August 1993. An increase was observed in CVD-related coverage in the pre-intervention period (mean articles per month = 31.5) compared with the post-intervention period (mean articles per month = 50.7) (F = 10.2; P = 0.003). In supporting data from a separate randomized risk factor survey of 1510 residents in the same area, respondents reported hearing of heart health coalitions primarily through local newspapers. The current study documents increasing print media coverage of cardiovascular health issues in a high-risk, rural area and shows that media content analysis can be a useful evaluation tool in community-based interventions.

Cardiovascular Diseases↗
PubMed1995

The genome of Arabidopsis thaliana.

Arabidopsis thaliana is a small flowering plant that is a member of the family cruciferae. It has many characteristics--diploid genetics, rapid growth cycle, relatively low repetitive DNA content, and small genome size--that recommend it as the model for a plant genome project. The current status of the genetic and physical maps, as well as efforts to sequence the genome, are presented. Examples are given of genes isolated by using map-based cloning. The importance of the Arabidopsis project for plant biology in general is discussed.

Arabidopsis↗
PubMed1995

Physical map and organization of Arabidopsis thaliana chromosome 4.

A physical map of Arabidopsis thaliana chromosome 4 was constructed in yeast artificial chromosome clones and used to analyze the organization of the chromosome. Mapping of the nucleolar organizing region and the centromere integrated the physical and cytogenetic maps. Detailed comparison of physical with genetic distances showed that the frequency of recombination varied substantially, with relative hot and cold spots occurring along the whole chromosome. Eight repeated DNA sequence families were found in a complex arrangement across the centromeric region and nowhere else on the chromosome.

Arabidopsis↗
PubMed1995

QTL analysis of flowering time in Arabidopsis thaliana.

Quantitative trait loci (QTL) analyses based on restriction fragment length polymorphism maps have been used to resolve the genetic control of flowering time in a cross between two Arabidopsis thaliana ecotypes H51 and Landsberg erecta, differing widely in flowering time. Five quantitative trait loci affecting flowering time were identified in this cross (RLN1-5), four of which are located in regions containing mutations or loci previously identified as conferring a late-flowering phenotype. One of these loci is coincident with the FRI locus identified as the major determinant for late flowering and vernalization responsiveness in the Arabidopsis ecotype Stockholm. RLN5, which maps to the lower half of chromosome five (between markers mi69 and m233), only affected flowering time significantly under short day conditions following a vernalization period. The late-flowering phenotype of H51 compared to Landsberg erecta was due to alleles conferring late flowering at only two of the five loci. At the three other loci, H51 possessed alleles conferring early flowering in comparison to those of Landsberg erecta. Combinations of alleles conferring early and late flowering from both parents accounted for the transgressive segregation of flowering time observed within the F2 population. Three QTL, RLN1, RLN2 and RLN3 displayed significant genotype-by-environment interactions for flowering time. A significant interaction between alleles at RLN3 and RLN4 was detected.

Alleles↗
PubMed1995

Patterns of gene action in plant development revealed by enhancer trap and gene trap transposable elements.

The crucifer Arabidopsis thaliana has been used widely as a model organism for the study of plant development. We describe here the development of an efficient insertional mutagenesis system in Arabidopsis that permits identification of genes by their patterns of expression during development. Transposable elements of the Ac/Ds system carrying the GUS reporter gene have been designed to act as enhancer traps or gene traps. A novel selection scheme maximizes recovery of unlinked transposition events. In this study 491 plants carrying independent transposon insertions were generated and screened for expression patterns. One-half of the enhancer trap insertions and one-quarter of the gene trap insertions displayed GUS expression in seedlings or flowers, including expression patterns specific to organs, tissues, cell types, or developmental stages. The patterns identify genes that act during organogenesis, pattern formation, or cell differentiation. Transposon insertion lines with specific GUS expression patterns provide valuable markers for studies of Arabidopsis development and identify new cell types or subtypes in plants. The diversity of gene expression patterns generated suggests that the identification and cloning of Arabidopsis genes expressed in any developmental process is feasible using this system.

Arabidopsis↗
PubMed1995

Discharge patterns of baroreceptor-modulated neurons in the nucleus tractus solitarius.

Activity of baroreceptor-modulated neurons in the nucleus tractus solitarius (NTS) was recorded extracellularly during selective pressure stimulation of carotid baroreceptors, using an isolated carotid sinus preparation in anesthetized dogs. One of two different patterns of activity was recorded from individual baro-sensitive neurons in response to slow ramp increases in carotid sinus pressure. The cause of these two distinct firing patterns is not known but preliminary results indicate that it may be due in part to input from different functional types of baroreceptors. These results suggest that some differentiation in blood pressure control may be encoded in the responses of central baro-sensitive neurons in the NTS.

Anesthesia↗
PubMed1995

An adoption study comparing the prevalence of psychiatric illness in women who have adoptive and natural children compared with women who have adoptive children only.

The current study compares the current and lifetime prevalence of affective disorder in women who have adopted and have natural children (n = 110) with women who only have adopted children (n = 176). There was no difference in lifetime prevalence of psychiatric disorder between the two groups and a nonsignificant trend for women who had born children to have had a major depressive episode during their lifetime 48 (44%) cf 62 (35%). The increased prevalence of psychiatric illness in married women with children cannot be explained by the biological fact of bearing children. None of the social variables related to child-rearing which were examined influenced the lifetime prevalence of psychiatric disorder.

Adoption↗
PubMed1995

The binding of HB-EGF to tumour cells is blocked by mAbs which act as EGF and TGF alpha antagonists.

Heparin binding EGF (HB-EGF), a newly discovered member of the EGF family of mitogens, binds to the EGF receptor (EGFR) and to heparan sulfate proteoglycans on the cell surface. Here, we show that the binding of HB-EGF to the EGFR is inhibited by mAbs which prevent the interaction of EGF and TGF alpha with the receptor. Also, we show that, like EGF and TGF alpha, treatment with HB-EGF inhibits the growth in vitro of tumours (HN5, HSC-4) that overexpress the EGFR. We conclude that mAbs which act as EGF and TGF alpha antagonists should also be effective therapeutic agents for blocking the growth of EGFR overexpressing tumours induced by HB-EGF.

Antibodies, Monoclonal↗
PubMed1995

Safety of intravenous valproate.

This multicenter, open-label trial was designed to study the safety of intravenous (IV) sodium valproate in patients with epilepsy. All 318 patients (previously treated with antiepileptic drugs) were hospitalized for seizure control or anticipated seizures. The protocol allowed physicians to set the number of infusions and treatment duration. Adverse events, laboratory studies performed, and seizure activity were documented on case report forms. The patients' mean age was 34.4 years (range, 2-87 years). The most common reason for admission was lack of seizure control (235 patients, 185 of whom were admitted for video-electroencephalographic monitoring). The median dosage of valproate was 375 mg infused over 1 hour. The median number of doses was four, given over 2 days. In 54 patients (17%), transient adverse events were reported. The most frequent were headache, reaction at the injection site, and nausea (2.2% each); somnolence (1.9%); vomiting (1.6%); and dizziness and taste perversion (1.3% each). No persistent or severe hematologic or serum chemistry abnormalities were found. Vital signs were not significantly affected by the IV infusion of valproate. At the dosages and rates of administration studied, intravenous valproate appears to be safe and well tolerated.

Adolescent↗
PubMed1995

TGF-betas upregulate NCAM and L1 expression in cultured Schwann cells, suppress cyclic AMP-induced expression of O4 and galactocerebroside, and are widely expressed in cells of the Schwann cell lineage in vivo.

We have examined both how the molecular phenotype of Schwann cells in vitro is regulated by transforming growth factor beta (TGF-beta), using immunohistochemistry and immunoblotting, and the distribution of TGF-beta 2 and 3 in embryonic and mature nerves and ganglia, using immunohistochemistry and in situ hybridisation. We find that TGF-beta 2 and -3 upregulate expression of the neural cell adhesion molecules NCAM and L1. In TGF-beta-treated cultures, in addition to the 140 and 120 kD isoforms known to be present in Schwann cells, small amounts of the 180 kD isoform can be detected. TGF-beta s also block cAMP-induced expression of the lipid antigens galactocerebroside (GalC) and O4, in addition to blocking expression of protein zero (P0), the major peripheral myelin glycoprotein, as previously shown. Using antibodies specific to TGF-beta 2 and -3, respectively, we confirm the presence of these proteins in myelin-forming Schwann cells and show also that TGF-beta 2 and -3 are clearly expressed by peripheral glia that are not involved in myelination. This includes Schwann cell precursors, embryonic Schwann cells, non-myelin-forming Schwann cells and satellite cells from adult nerves and ganglia, and neonatal Schwann cells in purified cultures without neurones. In situ hybridisation with a digoxygenin-labelled riboprobe reveals a strong TGF-beta 3 mRNA signal in Schwann cells, satellite cells, and some neurones. Schwann cells in culture also secrete TGF-beta in a latent form, whereas purified cultures of dorsal root ganglion neurones from 1-day-old rats secrete active TGF beta during the first 48 h in culture.

Animals↗
PubMed1995

Primary structure of the variable regions encoding antibody to NG2, a tumour-specific antigen on the rat chondrosarcoma HSN. Correlation of idiotypic specificities with amino acid sequences.

Eight syngeneic rat monoclonal antibodies that recognize structurally overlapping epitopes on the chondroitin proteoglycan NG2, a tumour-specific antigen on the chemically induced rat chondrosarcoma HSN, have been analysed for the sequence of their immunoglobulin heavy (H) and light (L) chain variable (V) regions. This analysis defined five groups of antibodies which are very similar for both the H and L chains and revealed that a wide range of different V regions are capable of binding to the same antigenic determinant. However, three mAbs, 11/160, ALN/12/17 and ALN/9/94, which recognize a sequential epitope, were found to use almost identical heavy (V-D-J) and light (V-J) chains in regions demonstrating an exclusivity in specific protein-protein interaction for this particular epitope. Two other mAbs, ALN/11/53 and AL/3/12, used similar V and J segments but totally different D regions. With the exception of the pair ALN/11/53 and AL/3/12, this grouping of antibodies matches that derived from the idiotypic specificity study we have reported previously. The reactivity pattern of Ab1 11/160, ALN/12/17 and ALN/9/94 with six anti-idiotopic mAbs raised against 11/160 demonstrated that the idiotope recognized by Ab2 HIM/3/41 was defined by a single amino acid, Asn, at position 52 within the CDR2 loop of the VH region; whereas the D region of Ab1 ALN/11/53 was implicated as the structural correlate of idiotypy. The substitution of AsnH52 influenced the Id recognition but Ag binding was not affected suggesting that Ab2 HIM/3/41 did not mimic the NG2 Ag.

Amino Acid Sequence↗
PubMed1995

Expression of c-fos protein in the nucleus tractus solitarius in response to physiological activation of carotid baroreceptors.

This study has utilized unilateral physiological pressure stimulation f a vascularly isolated carotid sinus combined with c-fos immunohistochemistry to locate neurons of the nucleus tractus solitarius which are activated by carotid baroreceptors in the anesthetized, vagotomized dog. Carotid baroreceptor stimulation primarily activated neurons in the ipsilateral commissural and medial subnuclei of the caudal nucleus tractus solitarius. In the intermediate and rostral nucleus tractus solitarius, carotid baroreceptor stimulation activated neurons in the dorsal and medial subnuclei. Results from this study also suggested that different subgroups of nucleus tractus solitarius neurons may be activated by baroreceptors with different pressure thresholds. The use of c-fos immunohistochemistry in this study has enabled the definition of populations of dorsal medullary neurons in the carotid baroreflex pathway. The results also suggest a different projection of carotid baroreceptors with different pressure thresholds.

Animals↗
PubMed1994

Modification of the 5' untranslated leader region of the maize Activator element leads to increased activity in Arabidopsis.

In contrast to its behavior in tobacco and tomato, the maize transposable element Ac is relatively inactive in Arabidopsis. We show here that removal of 537 bp within a CpG-rich region of the Ac 5' untranslated leader region significantly increases the excision frequency of the element in Arabidopsis. This increase did not appear to be correlated with the removal of sequences that are methylated in inactive Ac elements in maize, as these sites were not methylated in Ac elements in Arabidopsis transformants. The deletion within the 5' untranslated leader did not increase Ac activity by increasing levels of steady-state transposase mRNA, as assayed by RNase protection experiments. Moreover, there was no correlation between the levels of steady-state transposase mRNA and Ac element activity. This suggests that post-transcriptional regulation of Ac activity occurs in Arabidopsis.

Arabidopsis↗
PubMed1994

The chondroitin sulfate proteoglycan NG2 is a tumour-specific antigen on the chemically induced rat chondrosarcoma HSN.

N-terminal sequences of 19 and 11 amino acids obtained from 2 different tryptic fragments of the tumour-specific antigen on the chemically induced rat chondrosarcoma HSN show a 100% homology with the rat chondroitin sulfate proteoglycan NG2. Using a scheme of overlapping oligonucleotide primers we have cloned by PCR amplification the cDNA for the specific antigen of the HSN tumour that is immunogenic in immunocompetent CBH/Cbi rats and now report that its cDNA sequence is identical to that of NG2. The cDNA codes for a transmembrane protein of 2,325 amino acids with a large extracellular domain of 2,224 amino acids containing 2 cysteine-rich regions, a transmembrane domain (25 amino acids) and a short cytoplasmic tail (76 amino acids). The tumour-specific determinant was found to lie between amino acid residues 556 and 992 on the core glycoprotein.

Amino Acid Sequence↗