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Biomedical subjects

A S Law

Publications and source records attributed to A S Law.

At least 19 recordsLinked to original sources
PubMed2005

Detection of quantitative trait loci for androstenone, skatole and boar taint in a cross between Large White and Meishan pigs.

'Boar taint' is a strong perspiration-like, urine-like unpleasant odour given off upon heating or cooking of meat from some intact (uncastrated) male pigs. Data from the F(2) generation of a Large White (LW) x Meishan (MS) crossbred population were analysed to detect quantitative trait loci (QTL) for traits associated with boar taint. Fat samples from 178 intact male pigs slaughtered at 85 +/- 5 kg were analysed for the major contributors to boar taint (androstenone, indole and skatole). Fat and lean samples from cooked meat were scored for boar, abnormal and pork flavour and odour by a trained sensory panel (SP). A scan with 117 markers covering the whole genome was performed in the F(2) individuals, together with their F(1) parents and purebred grandparents. At the 5% chromosomal significance threshold (approximately equal to the genome-wide suggestive significance threshold), QTL were detected for the laboratory estimate of androstenone on chromosomes 2, 4, 6, 7 and 9. However, only on chromosome 6 were there QTL for boar flavour (BF) traits in the same or adjacent marker intervals as a QTL for the laboratory estimate of androstenone. On chromosome 14, QTL were detected for the laboratory estimates of indole and skatole, the SP score for skatole and the scores for BF in lean and BF in fat. In all five cases, the MS allele generally increased the estimate or score, compared with the LW allele, but it appeared that desirable and undesirable alleles were present in both breeds. This locus on chromosome 14 has considerable potential for use to reduce the incidence of boar taint, especially if further research can identify the causative polymorphism or strongly associated markers.

Androsterone↗
PubMed2003

Establishment of a sequence-based typing system for BoLA-DRB3 exon 2.

A rapid, high-resolution sequence-based typing (SBT) system for BoLA-DRB3 exon 2 was developed. Amplification of the entire exon was achieved by a fully nested PCR with locus-specific primers and sequencing was performed directly on the PCR product. Heterozygous sequence data were obtained by automated sequence analysis of both alleles. Forward and reverse sequence data were assembled to improve identification of all heterozygous positions. Specific software (Haplofinder, Roslin Institute Software, Roslin, UK) was designed for allele assignment. Fifty-four females from a Holstein-Charolais resource herd cross, their 12 sires and five unrelated Holstein animals were used to establish the method. In parallel, these animals were typed by DRB3 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to confirm the results. Polymerase chain reaction-RFLP analysis defined 15 known types in the 71 animals, while SBT of the same animals showed 19 known alleles. Subsequently, 72 more animals from the same resource herd were typed by the established SBT method without PCR-RFLP typing. This SBT strategy and the Haplofinder software can be applied to the analysis of any polymorphic locus for which suitable locus-specific primers and allelic sequences are available.

Alleles↗
PubMed2001

Retreatment versus initial root canal treatment: factors affecting posttreatment pain.

OBJECTIVE: The purpose of this study was to determine the factors associated with posttreatment pain in patients receiving root canal retreatment (RCR) and in those receiving initial root canal treatment (IRCT). STUDY DESIGN: Eighty four patients scheduled for RCR or IRCT completed questionnaires on pretreatment pain levels (Visual Analogue Scale, 0-100) and demographic data. Diagnosis and original obturating material, if applicable, were also recorded, and treatment was initiated. At 4, 8, 12, 24, 48, 72, 96, and 120 hours, patients recorded posttreatment pain levels. Seventy one patients returned completed questionnaires. RESULTS: There was no significant difference in posttreatment pain with respect to patients undergoing RCR and patients undergoing IRCT, type of original obturating material, or pretreatment diagnosis. Posttreatment pain levels were significantly increased at 4, 8, and 12 hours after treatment. Patients reporting higher levels of pretreatment pain (Visual Analogue Scale > 20) had significantly increased posttreatment pain (P <.05) up to 24 hours after the procedure. CONCLUSIONS: Pretreatment pain level influenced posttreatment pain more than RCR or IRCT, the type of original obturating material, or the pretreatment diagnosis.

Acute Disease↗
PubMed2000

Differences in gene density on chicken macrochromosomes and microchromosomes.

The chicken karyotype comprises six pairs of large macrochromosomes and 33 pairs of smaller microchromosomes. Cytogenetic evidence suggests that microchromosomes may be more gene-dense than macrochromosomes. In this paper, we compare the gene densities on macrochromosomes and microchromosomes based on sequence sampling of cloned genomic DNA, and from the distribution of genes mapped by genetic linkage and physical mapping. From these different approaches we estimate that microchromosomes are twice as gene-dense as macrochromosomes and show that sequence sampling is an effective means of gene discovery in the chicken. Using this method we have also detected a conserved linkage between the genes for serotonin 1D receptor (HTR1D) and the platelet-activating factor receptor protein gene (PTAFR) on chicken chromosome 5 and human chromosome 1p34.3. Taken together with its advantages as an experimental animal, and public access to genetic and physical mapping resources, the chicken is a useful model genome for studies on the structure, function and evolution of the vertebrate genome.

Animals↗
PubMed2000

An evaluation of preoperative ibuprofen for treatment of pain associated with orthodontic separator placement.

Patients undergoing orthodontic treatment can experience significant levels of pain. This study assessed the effectiveness of preoperative ibuprofen in reducing the incidence and the severity of pain after orthodontic separator placement. Sixty-three adolescent patients (mean age, 13 years) were included in this randomized, double-blind, placebo-controlled, prospective study. Patients were randomly assigned to 1 of 3 experimental conditions: (1) 400 mg of ibuprofen taken orally 1 hour before separator placement and a lactose placebo taken orally immediately after the appointment, (2) a lactose placebo taken orally 1 hour before separator placement and 400 mg of ibuprofen taken orally immediately after the appointment, or (3) a lactose placebo taken orally 1 hour before separator placement and again immediately after the appointment. The patient's level of discomfort was assessed with a visual analog scale at 2, 6, and 24 hours, as well as at 2, 3, and 7 days after placement of the orthodontic separators. An analysis of variance and Duncan's multiple range test revealed that 2 hours after their orthodontic appointment the patients who had taken ibuprofen 1 hour before separator placement had significantly less pain with chewing than did the patients who received either ibuprofen postoperatively or a placebo. Additional measures suggest a trend for less pain for this group of patients. These results support the use of pretreatment ibuprofen for patients requiring analgesics for orthodontic discomfort. Future study of the use of preemptive analgesics in orthodontics is warranted.

Adolescent↗
PubMed2000

Farm animal genome databases.

The requirements for bioinformatics resources to support genome research in farm animals is reviewed. The resources developed to meet these needs are described. Resource databases and associated tools have been developed to handle experimental data. Several of these systems serve the needs of multinational collaborations. Genome databases have been established to provide contemporary summaries of the status of genome maps in a range of farm and domestic animals along with experimental details and citations. New resources and tools will be required to address the informatics needs of emerging technologies such as microarrays. However, continued investment is also required to maintain the currency and utility of the current systems, especially the genome databases.

Animals↗
PubMed1999

The dynamics of chromosome evolution in birds and mammals.

Comparative mapping, which compares the location of homologous genes in different species, is a powerful tool for studying genome evolution. Comparative maps suggest that rates of chromosomal change in mammals can vary from one to ten rearrangements per million years. On the basis of these rates we would expect 84 to 600 conserved segments in a chicken comparison with human or mouse. Here we build comparative maps between these species and estimate that numbers of conserved segments are in the lower part of this range. We conclude that the organization of the human genome is closer to that of the chicken than the mouse and by adding comparative mapping results from a range of vertebrates, we identify three possible phases of chromosome evolution. The relative stability of genomes such as those of the chicken and human will enable the reconstruction of maps of ancestral vertebrates.

Animals↗
PubMed1999

Localization and changes in superoxide dismutase immunoreactivity in rat pulp after tooth preparation.

OBJECTIVE: To examine the distribution of superoxide in the uninflamed and inflamed dental pulp by characterizing the immunoreactivity of the detoxifying antioxidant enzymes, manganese and copper-zinc superoxide dismutases (MnSOD and CuZnSOD, respectively). STUDY DESIGN: In 12 rats, mesial cavity preparations were made on the maxillary right first molar; left molars were unoperated controls. After 5 days, the rats were killed, and histologic sections were processed by using MnSOD and CuZnSOD immunoreactivity, and the extent of inflammation was evaluated on alternate sections stained with hematoxylin and eosin. RESULTS: In the hematoxylin and eosin-stained sections, inflammation was consistent with round-cells: macrophages, lymphocytes, and plasma cells that coalesced into a distinct leukocytic "lesion", which obliterated portions of the underlying pulp. Both MnSOD and CuZnSOD immunoreactivity increased dramatically in inflammatory cells within the leukocytic lesion and in the tissue surrounding the lesion. CONCLUSIONS: The findings suggest that the protective role of SOD increases within pulp cells that are undergoing inflammatory stimulation. SOD immunoreactivity may be an early indicator of stress in pulp.

Animals↗
PubMed1999

Localization and changes in NADPH-diaphorase reactivity and nitric oxide synthase immunoreactivity in rat pulp following tooth preparation.

Inflammatory changes in the dental pulp are accompanied by release of a wide variety of chemical mediators. Nitric oxide, an oxidative free radical produced by the enzyme nitric oxide synthase (NOS), has been implicated in multiple inflammatory processes, which makes it a suitable marker for changes which likely occur following tooth pulp insult. Since limited information on nitric oxide in the pulp is available, it is necessary first to examine relative distributions of NOS in uninflamed and inflamed rat pulp. We accomplished this by characterizing regions of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity and the distribution of both macrophage NOS (macNOS) and neuronal NOS (nNOS) immunoreactivity in normal and inflamed rat molar pulp at multiple time points. The results showed that: (1) deep cavity preparation on the mesial surface of the molar produced a time-dependent inflammation, with acute inflammation early progressing to chronic, granulomatous inflammation with necrosis later that spread preferentially down the mesial root; (2) control (non-prepared) teeth showed a relatively faint and homogeneous distribution of NADPH-d and macNOS reactivity but no discernible nNOS reactivity; (3) inflamed teeth displayed localized increased intensity of NADPH-d and macNOS reactivity surrounding the inflamed area of pulp, but no increased nNOS activity; (4) pulp vessels supplying the inflamed area showed increased NADPH-d reactivity, but no increased macNOS or nNOS reactivity; and (5) neither NADPH-d, macNOS, nor nNOS reactivity was observed in pulpal nerves. Therefore, nitric oxide may mediate the pulpal inflammatory response through its effects on the paralesional pulp tissue and surrounding endothelial/vascular structures.

Analysis of Variance↗
PubMed1997

Atypical odontalgia misdiagnosed as odontogenic pain: a case report and discussion of treatment.

Atypical odontalgia is characterized by prolonged periods of throbbing or burning pain in the teeth or alveolar process, which occurs in the absence of any identifiable odontogenic etiology. The pain may be bilateral and change in location. This article presents two cases of atypical odontalgia that were misdiagnosed and initially treated as pain of odontogenic origin. A therapeutic regimen of tricyclic antidepressants alleviated the pain in one patient and was unsuccessful in the second. These two cases demonstrate the importance of having a thorough knowledge of both odontogenic and nonodontogenic causes of orofacial pain as well as the need for careful diagnosis before undertaking any treatment.

Aged↗
PubMed1997

Two applications to facilitate the viewing of database search result files on the Macintosh.

MOTIVATION: MacBOB (Macintosh BLAST Output Browser) and MacBOB Filter are two Macintosh-based applications that greatly simplify the viewing of BLAST and FASTA search results files. AVAILABILITY: The programs can be obtained via anonymous ftp from ftp.ri.bbsrc.ac.uk from the directory/pub/software/MacBOB, or via WWW from the Roslin Institute Home Page (http://www.ri.bbsrc.ac.uk/).

Base Sequence↗
PubMed1996

Expression of the gene for transforming growth factor-beta in avian dyschondroplasia.

Previous immunolocalisation studies of dyschondroplasia have indicated that there is a reduction in the number of growth plate chondrocytes containing the protein transforming growth factor beta 3 (TGF-beta 3). The reduction in TGF-beta 3 in dyschondroplasia is likely to be a direct result of a reduction in the expression of the TGF-beta 3 gene. mRNA was extracted from small (0.09 g) samples of growth cartilage from the proximal tibiotarsus of three-week-old broiler chicks. The cartilage samples contained cells from all three zones of the growth plate (proliferative, transitional and upper hypertrophic) and were collected from normal and dyschondroplastic growth plates. The dyschondroplastic growth plates were identified by an accumulation of transitional chondrocytes which were considered to be a result of a failure to differentiate to the hypertrophic phenotype. A semi-quantitative polymerase chain reaction (PCR) was used to estimate the quantity of mRNA specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and for each of the three isoforms of TGF beta (TGF-beta 1, TGF-beta 2 and TGF-beta 3) in each of the cartilage samples. The levels of expression of mRNA for GAPDH, TGF-beta 1 and TGF-beta 2 were similar in the two groups, but the expression of TGF-beta 3 mRNA was significantly reduced in the samples from the dyschondroplastic growth plates. The reduction in TGF-beta 3 levels is thought to be associated with the failure of chondrocyte hypertrophy in dyschondroplasia, and provides in vivo evidence that TGF-beta 3 is part of the cascade of events associated with the differentiation of chondrocytes during endochondral ossification in the chick.

Animals↗
PubMed1996

qValue--a program to calculate comparative measures of genomic reorganisation from cytogenetic and/or linkage information.

A program qValue, which calculates a measure of the genomic reorganisation that has occurred between pairs of species since their divergence from a common ancestor, is described. The program takes a tab-delimited text file containing data describing the location of various genetic loci in multiple species and generates an output text file, also in tab-delimited format, that lists various parameters of genomic reorganisation between all possible pairs of species considered. This provides a useful tool for the developing field of comparative genome mapping, particularly in the study of the evolution of the vertebrate genome.

Animals↗
PubMed1996

The expression of transforming growth factor-beta by cultured chick growth plate chondrocytes: differential regulation by 1,25-dihydroxyvitamin D3.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) and transforming growth factor-beta (TGF-beta) are both important regulators of chondrocyte growth and differentiation. We report here that 1,25(OH)2D3 differentially regulates the expression of the genes for TGF-beta 1 to -beta 3 and the secretion of the corresponding proteins in cultured chick chondrocytes. Confluent growth plate chondrocytes were serum-deprived and cultured in varying concentrations of 1,25(OH)2D3. Cells were assayed for TGF-beta mRNA and conditioned medium was assayed for TGF-beta activity and isoform composition. Active TGF-beta was only detected in 10(-8) M 1,25(OH)2D3-treated cultures (8.37 ng active TGF-beta/mg protein). There was a significant decrease in total (latent-active) TGF-beta activity in conditioned medium of 10(-12) M (23.4%; P < 0.05) and 10(-10) M (20.7%; P < 0.05) 1,25(OH)2D3-treated cultures but 10(-8) M 1,25(OH)2D3 significantly increased (30.9%; P < 0.01) TGF-beta activity. The amounts of TGF-beta 1, -beta 2 and -beta 3 isoforms produced were similar in control, 10(-10) or 10(-12) M 1,25(OH)2D3-treated cultures but the conditioned medium of 10(-8) M 1,25(OH)2D3-treated cultures contained significantly higher amounts of all three isoforms. Quantification of TGF-beta mRNA demonstrated differential control of TGF-beta gene expression with TGF-beta 1 and -beta 3 mRNA levels reduced by all concentrations of 1,25(OH)2D3 examined (10(-8), 10(-10) and 10(-12) M) whilst TGF-beta 2 mRNA concentrations were elevated. Our results indicated that 1,25(OH)2D3 regulates chick growth plate chondrocyte TGF-beta secretion and mRNA expression in a concentration-dependent and isoform-specific manner. This interaction may be important in the regulation of chondrocyte metabolism and endochondral bone growth.

Animals↗
PubMed1995

Expression of transforming growth factor-beta mRNA in chicken ovarian follicular tissue.

RNA was isolated from chicken thecal tissue from the largest (F1), third largest (F3), and fifth largest (F5) preovulatory follicles, from small yolky follicles, and from granulosa tissue from F1 follicles. Transforming growth factor-beta (TGF-beta) gene expression was measured using reverse transcription polymerase chain reaction. Thecal cells from all follicle sizes expressed all three isoforms of TGF-beta. TGF-beta 1 mRNA was detected in granulosa cells at levels comparable to those seen in thecal cells. However, TGF-beta 2 and TGF-beta 3 mRNA was expressed at significantly lower levels in granulosa than in thecal tissue. This is the first demonstration of TGF-beta gene expression in the ovary of a nonmammalian species. The similarities between mammalian and avian TGF-beta gene expression are remarkable, especially in light of the distinctive patterns of avian follicular development and the differing steroidogenic capacities of ovarian cell types of the two classes of vertebrates.

Animals↗
PubMed1995

Trigeminal neuralgia mimicking odontogenic pain. A report of two cases.

Trigeminal neuralgia or tic douloureux is characterized by paroxysmal episodes of facial pain in the distribution of the trigeminal nerve, although patients may have a variety of symptoms that mimic odontogenic pain. This article presents two cases of trigeminal neuralgia that were misdiagnosed and initially treated endodontically as pain of odontogenic origin. A therapeutic regimen of carbamazepine alleviated the pain in both patients. These two cases demonstrate the importance of having a thorough knowledge of both odontogenic and nonodontogenic causes of orofacial pain, as well as the need for careful diagnosis before undertaking any treatment.

Aged↗