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Biomedical subjects

J F Taylor

Publications and source records attributed to J F Taylor.

At least 37 records · Page 2Linked to original sources
PubMed2001

Right atrial reduction for tachyarrhythmias in Ebstein's anomaly in infancy.

A 20-month-old girl with Ebstein's anomaly developed supraventricular paroxysmal tachycardia, which seemed to be a result of the wall tension of the giant right atrium. Right atrial resection reduced the wall tension and overall dimensions of the right atrium and finally resolved the tachycardia and ectopic electrical conduction. Six-year follow-up electrocardiograms confirmed continuing normal sinus rhythm without occurrence of supraventricular paroxysmal tachycardia or other ectopic electrical activity The follow-up echocardiograms showed the size of the right atrium to be unchanged from the time of operation. There are few data in the available literature about performing right atriotomy to resolve a tachyarrhythmia associated with Ebstein's anomaly and none, to the best of our knowledge, about performing right atrial resection for this purpose.

Cardiomegaly↗
PubMed2001

Mining the mammalian genome for artiodactyl systematics.

A total of 7,806 nucleotide positions derived from one mitochondrial and eight nuclear DNA segments were used to provide a robust phylogeny for members of the order Artiodactyla. Twenty-four artiodactyl and two cetacean species were included, and the horse (order Perissodactyla) was used as the outgroup. Limited rate heterogeneity was observed among the nuclear genes. The partition homogeneity tests indicated no conflicting signal among the nuclear genes fragments, so the sequence data were analyzed together and as separate loci. Analyses based on the individual nuclear DNA fragments and on 34 unique indels all produced phylogenies largely congruent with the topology from the combined data set. In sharp contrast to the nuclear DNA data, the mtDNA cytochrome b sequence data showed high levels of homoplasy, failed to produce a robust phylogeny, and were remarkably sensitive to taxon sampling. The nuclear DNA data clearly support the paraphyletic nature of the Artiodactyla. Additionally, the family Suidae is diphyletic, and the nonruminating pigs and peccaries (Suiformes) were the most basal cetartiodactyl group. The morphologically derived Ruminantia was always monophyletic; within this group, all taxa with paired bony structures on their skulls clustered together. The nuclear DNA data suggest that the Antilocaprinae account for a unique evolutionary lineage, the Cervidae and Bovidae are sister taxa, and the Giraffidae are more primitive.

Animals↗
PubMed2000

Alternative splicing for the alpha1 subunit of soluble guanylate cyclase.

Soluble guanylate cyclase (sGC), the receptor for nitric oxide, is a heterodimer consisting of alpha and beta subunits. We investigated the mRNA species for the alpha(1) subunit in human brain, heart, artery and immortalized B-lymphocytes. Three mRNA species were identified in these tissues. The major mRNA species contained the full expression sequence of the alpha(1) subunit. Two other types of mRNA were detected in which 5' sequences were deleted by splicing (506-590 and 412-590). Each of these deletions included the predicted translation start site, indicating that translation of these two alternatively spliced RNA species does not result in the production of full-length alpha(1) subunits. The relative amounts of the two mRNA species with deletions of the translation start site differed significantly between cell lines of immortalized B-lymphocytes from different individuals. sGC enzymic activity was significantly decreased in cellular extracts from cell lines with high proportions of mRNA species containing the deletion 506-590 when compared with extracts from cell lines that contained mostly mRNA without this deletion.

Adult↗
PubMed2000

Phylogeography of the Caribbean rock iguana (Cyclura): implications for conservation and insights on the biogeographic history of the West Indies.

The Caribbean rock iguana, Cyclura, has had an unstable intrageneric taxonomy and an unclear phylogenetic position within the family Iguanidae. We use mtDNA sequence data to address these issues and explore the phylogeographic history of the genus. ND4 to leucine tRNA sequence data were collected from multiple individuals of each of the eight species of Cyclura (including 15 of 16 subspecies) and from four localities of Iguana iguana (representative of this species' broad geographic range). This data set was combined with sequence data from Sites et al. (1996, Mol. Biol. Evol. 13, 1087-1105) and analyzed under maximum-parsimony and maximum-likelihood optimization criteria. The ND4 region provided good resolution for the majority of nodes, as indicated by high bootstrap support. In agreement with several recent molecular studies, Cyclura is recovered as monophyletic and is not closely related to any other genus, whereas Iguana is strongly supported as the sister taxon to Sauromalus. This result is statistically more likely than other published hypotheses of Iguanid relationships. Cyclura shows a southeast to northwest speciation sequence in the Caribbean, with the most ancient lineage on the Puerto Rican Bank. The amount of interspecific sequence divergence within Cyclura (maximum 11.4%) is very high in comparison to data from other iguanid taxa at this locus, suggesting that this group either has been in the Caribbean for a very long time or has gone through a very rapid rate of evolution at this locus. Using dates from other published studies, we calculate a molecular clock that suggests that Cyclura colonized the Caribbean between 15 and 35 mya. Several questions regarding subspecific taxonomy are raised in the analysis and await further investigation using a more rapidly evolving marker such as nuclear microsatellites.

Animals↗
PubMed2000

Consensus and comprehensive linkage maps of bovine chromosome 7.

The objective of this project was to integrate the currently available linkage maps for bovine chromosome 7 (BTA7) by combining data sets from eight research groups. A total of 54 unique markers were typed in eight pedigrees. Multilocus linkage analysis with CRI-MAP produced a bovine chromosome 7 consensus framework map of 27 loci ordered with odds greater than 1000:1. Furthermore, we present a bovine chromosome 7 comprehensive map integrating 54 loci. The locus order is in general agreement with the recently published linkage maps except for one discrepancy. The order of loci BM9289, BMS713, and ILSTS001 was reversed in the consensus framework map relative to the published USDA-MARC bovine chromosome 7 linkage map.

Animals↗
PubMed1999

Fine-mapping of quantitative trait loci by identity by descent in outbred populations: application to milk production in dairy cattle.

We previously mapped a quantitative trait locus (QTL) affecting milk production to bovine chromosome 14. To refine the map position of this QTL, we have increased the density of the genetic map of BTA14q11-16 by addition of nine microsatellites and three single nucleotide polymorphisms. Fine-mapping of the QTL was accomplished by a two-tiered approach. In the first phase, we identified seven sires heterozygous "Qq" for the QTL by marker-assisted segregation analysis in a Holstein-Friesian pedigree comprising 1,158 individuals. In a second phase, we genotyped the seven selected sires for the newly developed high-density marker map and searched for a shared haplotype flanking an hypothetical, identical-by-descent QTL allele with large substitution effect. The seven chromosomes increasing milk fat percentage were indeed shown to carry a common chromosome segment with an estimated size of 5 cM predicted to contain the studied QTL. The same haplotype was shown to be associated with increased fat percentage in the general population as well, providing additional support in favor of the location of the QTL within the corresponding interval.

Animals↗
PubMed1999

A comparative linkage and physical map of bovine chromosome 24 with human chromosome 18.

Polymorphic microsatellites have been developed in the vicinity of nine genes on bovine chromosome (BTA) 24, all orthologous to genes on human chromosome (HSA) 18. The microsatellites have been isolated from bacterial and yeast artificial chromosome clones containing the genes. A linkage map was developed including these polymorphic markers and four anonymous, published microsatellites. Yeast artificial chromosomes containing six of these genes have also been mapped using fluorescent in situ hybridization (FISH), thereby tying the linkage map together with the physical map of BTA24. Comparing gene location on HSA18 and BTA24 identifies four regions of conserved gene order, each containing at least two genes. These genes identify six regions of conserved order between human and mouse, two more than in the human-bovine comparison. The breakpoints between regions of conserved order for human-bovine are also breakpoints in the human-mouse comparison. The centromere identifies a fifth conserved region if the BTA24 centromere is orthologous with the HSA18 centromere.

Animals↗
PubMed1999

Removal of a foreign body from the bronchial tree--a new method.

Tracheo-bronchial foreign bodies can be very difficult to remove. This may be related to the location and type of foreign body, the experience of the bronchoscopist and the availability of appropriate instruments. We report a case of an uncommon foreign body in an unusual location in an adolescent in whom conventional attempts to remove it failed. The foreign body was eventually recovered using a flexible bronchoscope and an intravascular wire loop snare under fluoroscopic control. The patient was saved from thoracotomy and possible lobectomy. To our knowledge, this combined fluoroscopic and endoscopic approach for the removal of a difficult tracheobronchial foreign body is the first reported case in the literature.

Adolescent↗
PubMed1999

Cytogenetic alignment of the bovine chromosome 13 genome map by fluorescence in-situ hybridization of human chromosome 10 and 20 comparative markers.

A bovine bacterial artificial chromosome (BAC) library was screened for the presence of six genes (IL2RA, VIM, THBD, PLC-II, CSNK2A1 and TOP1) previously assigned to human chromosomes 10 or 20 (HSA10 or HSA20). Four of the genes were found represented in the bovine BAC library by at least one clone. The identified BAC clones were used as probes in single-color fluorescence in-situ hybridization (FISH) to determine the chromosomal band location of each gene. As predicted by the human/bovine comparative map and comparative chromosome painting analysis, the four genes mapped to bovine chromosome 13 (BTA13). Dual-color FISH was then used to integrate these four type I markers into the existing BTA13 genome map. These FISH results anchor the BTA13 genome map from bands 14-23, and confirm the presence of a conserved HSA10 homologous synteny group on BTA13 centromeric to a HSA20 homologous segment.

Animals↗
PubMed1999

A molecular cytogenetic analysis of the tribe Bovini (Artiodactyla: Bovidae: Bovinae) with an emphasis on sex chromosome morphology and NOR distribution.

Q-band comparisons were made among representative species of the four genera of the tribe Bovini (Bos, Bison, Bubalus, Syncerus) as well as to selected outgroup taxa representing the remaining two tribes of the subfamily Bovinae (nilgai, Boselaphini; eland, Tragelphini), the Bovidae subfamily Caprinae (domestic sheep) and the family Cervidae (sika deer and white-tailed deer). Extensive autosomal arm homologies were noted, but relatively few derivative character states were shared. Focus was then made on variation of the sex chromosomes and the chromosomal distribution of nucleolar organizer regions (NORs). Bovine BAC clones were used in molecular cytogenetic analyses to decipher rearrangements of the sex chromosomes, and a pocket gopher 28s ribosomal probe was used to map the chromosomal locations of nucleolar organizing regions (NORs). Some of the more noteworthy conclusions drawn from the comparative analysis were that: 1. The Bovidae ancestral X chromosome was probably acrocentric and similar to acrocentric X chromosomes of the Bovinae; 2. The domestic sheep acrocentric X is probably a derivative character state that unites non-Bovinae subfamilies; 3. Bos and Bison are united within the tribe Bovini by the presence of shared derivative submetacentric X chromosomes; 4. Sika and white-tailed deer X chromosomes differ by inversion from X chromosomes of the Bovinae; 5. The Bovini ancestral Y chromosome was probably a small acrocentric; 6. Bos taurus, B. gaurus and B. banteng share derivative metacentric Y chromosomes; 7. Syncerus and Bubalus are united by the acquisition of X-specific repetitive DNA sequence on their Y chromosomes; 8. Bovinae and Cervidae X chromosome centromere position varies without concomitant change in locus order. Preliminary data indicate that a knowledge of the chromosomal distribution of NORs among the Bovidae will prove to be phylogenetically informative.

Animals↗
PubMed1999

Bovine chromosome 4 workshop: consensus and comprehensive linkage maps.

The report of the bovine chromosome 4 (BTA4) workshop is presented. Six laboratories contributed a total of 30,168 informative meioses from 62 loci. Twenty-two loci were typed by at least two independent laboratories and were used to construct a consensus linkage map of BTA4. The remaining 40 loci were subsequently incorporated into a comprehensive map. The sex-averaged consensus map covered 131.4 cM. The female map was 124.3 cM in length, while the male map was 134.3 cM. The comprehensive sex-averaged map spanned 141.6 cM. The length of the female and male comprehensive maps were 123.1 cM and 156.4 cM, respectively. Average genetic distance between loci was 6 and 2.3 cM for the consensus and comprehensive linkage maps, respectively.

Animals↗
PubMed1999

Comparative FISH-mapping of six expressed gene loci to river buffalo and sheep chromosomes.

Six expressed gene loci (NF1, CRYB1, CHRNB1, TP53, P4HB and GH1), recently assigned to cattle chromosome 19 by both radiation hybrid analysis and FISH-mapping, were comparatively FISH-mapped to river buffalo chromosome (BBU) 3p and sheep chromosome (OAR) 11, extending the physical map in these two important bovids. The six loci mapped to the same homoeologous chromosome bands of BBU 3p and OAR 11, and their gene order was centromere-NF1-CRYB1-CHNRB1-TP53-(GH1, P4HB).

Animals↗