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Biomedical subjects

W Davies

Publications and source records attributed to W Davies.

At least 37 records · Page 2Linked to original sources
PubMed1996

A comprehensive linkage map of the pig based on a wild pig-Large White intercross.

A comprehensive linkage map, including 236 linked markers with a total sex-average map length of about 2300 cM, covering nearly all parts of the pig genome has been established. Linkage groups were assigned to approximately all 18 autosomes, the X chromosome and the X/Y pseudoautosomal region. Several new gene assignments were made including the assignment of linkage group U1 (EAK-HPX) to chromosome 9. The linkage map includes 77 types I loci informative for comparative mapping and 72 in situ mapped markers physically anchoring the linkage groups on chromosomes. A highly significant heterogeneity in recombination rates between sexes was observed with a general tendency towards an excess of female recombination. The average ratio of female to male recombination was estimated at 1.4:1 but this parameter varied between chromosomes as well as between regions within chromosomes. An intriguing finding was that blood group loci were overrepresented at the distal ends of linkage groups.

Animals↗
PubMed1996

Laparoscopic versus open appendectomy: a prospective randomized trial of 81 patients.

OBJECTIVE: To compare the efficacy of laparoscopic appendectomy (LA) and open appendectomy (OA) in the treatment of acute appendicitis. DESIGN: A prospective randomized trial. SETTING: A university teaching hospital. PATIENTS: Eighty-one patients with a diagnosis of acute appendicitis were prospectively randomized to undergo either LA or OA. The two groups were matched for age and sex. INTERVENTIONS: LA or OA. MAIN OUTCOME MEASURES: Number of days in hospital and time to full recovery. RESULTS: The mean hospital stay for LA was 3.23 days compared with 3.03 days for OA (p < 0.001). The mean number of narcotic injections required for patients in the LA group was 4.05 compared with 5.58 for patients in the OA group (p < 0.001). The mean time to complete recovery for patients in the LA group was 9.0 days compared with 16.2 days for patients in the OA group (p < 0.001). The mean operative time for LA was 73.8 minutes compared with 45.0 minutes for OA (p < 0.001). Three patients in the LA group had intra-abdominal abscesses (p > 0.25). No significant difference in wound infection rates was demonstrated (p > 0.05). Similarly, pain scores at 7 and 28 days showed no significant difference (p > 0.05). CONCLUSIONS: With LA significantly fewer narcotic injections are required and there is a more rapid return to normal activities. LA takes longer to perform and was associated with three intra-abdominal abscesses. In cases of simple acute appendicitis the hospital stay for LA is significantly shorter.

Adult↗
PubMed1995

Awake oral fibreoptic intubation for caesarean section.

A 35-week pregnant patient with ankylosing spondylitis and a known previous failed intubation required an elective caesarean section for intrauterine growth retardation. Regional anaesthesia was prevented by extensive spinal fusion. The anaesthetic management involved an awake oral fibreoptic intubation followed by induction and maintenance of general anaesthesia allowing delivery of a live infant without harm to the mother.

Journal Article↗
PubMed1995

Extrahepatic biliary cystadenomas and cystadenocarcinoma. Report of seven cases and review of the literature.

OBJECTIVE: The aim of this investigation was to describe the clinical features, diagnosis, pathologic characteristics, and optimal surgical management for patients with extrahepatic biliary cystadenomas. SUMMARY BACKGROUND DATA: Extrahepatic biliary cystadenomas are rare epithelial neoplasms. The clinical features and optimal surgical management for these lesions have not been defined clearly. The usual presenting symptom is jaundice. These lesions should be considered premalignant and necessitate resection. Sporadic case studies have reported instances of recurrence with local excision. To the authors' knowledge, this study represents the largest collected single series of extrahepatic biliary cystadenomas and reviews previously reported cases. METHODS: The authors reviewed and reported their institutional experience from 1950 to 1993 in treating seven patients with extrahepatic biliary cystadenomas as well as 19 previously reported cases in the literature. RESULTS: A strong female predominance (96.3% of patients reviewed) was associated with extrahepatic biliary cystadenomas. Obstructive jaundice was the most common presenting symptom (85%). Abdominal pain occurred in 50% of patients; other symptoms included fever and hemobilia. The most common site of occurrence was the common hepatic duct (32%). Papillary cystadenoma with foci of invasive adenocarcinoma, thus supporting the malignant potential of cystadenomas, occurred in one patient. Local excision from the wall of the bile duct was performed in 18 patients and was associated with 50% recurrence within a mean follow-up of 13 months (range, 4-24 months). No recurrence was reported after formal sleeve resection and bilioenteric reconstruction. CONCLUSIONS: Extrahepatic biliary cystadenomas can become malignant, and in this study, local surgical excision was associated with a 50% local recurrence rate. Sleeve resection with negative histologic resection margins followed by bilioenteric reconstruction, therefore, is recommended.

Adenoma, Bile Duct↗
PubMed1995

Alignment of two genetic linkage maps on porcine chromosome 13.

A set of four microsatellite markers from the USDA genetic linkage map of porcine chromosome 13 were mapped in the European Pig Gene Mapping Project (PiGMaP) reference pedigrees. A two-point linkage analysis was performed between these markers and a set of markers known to map to chromosome 13. Pairs of markers that had a lod score greater than three were used to construct a multi-point linkage map, permitting alignment of the United States Department of Agriculture (USDA) map to the PiGMaP.

Animals↗
PubMed1995

Long-range mapping of the calcium release channel and glucosephosphate isomerase loci using pulsed-field gel electrophoresis.

Long range restriction maps of the calcium release channel (CRC) and glucosephosphate isomerase (GPI) loci have been constructed using pulsed field electrophoresis, Southern blotting and CRC- and GPI-specific probes. The maps, deduced from the restriction fragments detected by the probes, covered 1.1 and 0.3 Mb respectively and no overlap between the maps of these closely linked loci was detected. The minimal distance between the GPI and CRC loci was estimated to be at least 500 kb.

Animals↗
PubMed1994

Isolation of region-specific probes from pig chromosome 6 by coincidence cloning.

Coincidence cloning is a technique that permits the isolation of sequences common to two independent sources of complex DNA, and this method has been used to isolate a set of probes from a region of porcine Chromosome (Chr) 6 containing the loci for glucosephosphate isomerase (GPI) and the skeletal muscle calcium release channel (CRC). Porcine DNA was specifically PCR-amplified from a pig x hamster hybrid cell line containing the centromere region (p1.2-q1.2) of pig Chr 6 and other pig chromosome fragments by use of a porcine SINE specific primer with an EcoRI site in the 5'-end. Flow-sorted Chr 6 preparations were amplified with the same SINE primer, but with a SalI site in the 5'-end. The products were digested with EcoRI and SalI respectively, combined, denatured, and reannealed. The heteroduplex molecules, containing both an EcoRI and a SalI cohesive end, were selected by cloning in SalI/EcoRI-digested pUC13. Approximately 40% of the primary clones contained a single SalI/EcoRI-insert, indicating that they are coincidence clones. The average insert size was 1.4 kb. Fluorescence in situ hybridization of a pool of 34 coincidence clones to pig chromosomes showed a preferential labeling of the centromere region and of the q2.5-q2.7 region of pig Chr 6. Nineteen coincidence clones were hybridized to SINE-PCR products from flow-sorted pig Chr 6 and to pig x rodent hybrid cell lines. Eighteen clones gave positive signals correlated with the GPI/CRC content of the source DNAs.

Animals↗
PubMed1994

Characterization of microsatellites from flow-sorted porcine chromosome 13.

Porcine flow-sorted Chromosome (Chr) 13 was PCR amplified with primers based on porcine short interspersed element (SINE) sequences. The product was cloned, gridded in microtiter plates, and screened with a [GT]10 oligonucleotide which gave 45 positive clones. Sequencing of these clones showed that 36 were unique, and 26 [GT]n microsatellites were characterized. Six other simple repeat sequences, the majority of which were associated with the 3' end of the SINE sequence, were also detected. Twenty-one primers sets were selected, and 13 of these detected useful polymorphisms in the grandparents (n = 26) of the European porcine mapping collaboration (PiGMaP) reference families. These 13 markers were mapped in the "PiGMaP" reference families, and a two-point linkage analysis was performed. The Lod scores indicated that three of the markers were not linked and the remaining 11 formed two linkage groups of two and nine markers respectively. The larger linkage group was also linked to the transferrin locus, permitting assignment of nine markers to porcine Chr 13.

Animals↗
PubMed1993

A rare complication of dental treatment: Streptococcus oralis meningitis.

A case of Streptococcus oralis meningitis is reported. This followed extraction of a normal tooth during routine orthodontic treatment. No focus of infection could be demonstrated, either local to or distant from the extraction site. Full recovery followed hospital admission and intravenous benzyl penicillin.

Child↗
PubMed1993

Characterization of a porcine glucosephosphate isomerase-processed pseudogene at chromosome 1q1.6-1.7.

A porcine glucosephosphate isomerase-processed pseudogene has been isolated and sequenced. The pseudogene has several base substitutions as well as an insertion and deletions, and is 83% homologous to the corresponding cDNA. It contains an intervening sequence of 565 bp, is truncated at the 3' end, and is flanked by direct repeats of seven nucleotides. Fluorescent in situ hybridization to porcine metaphase chromosomes localized the processed pseudogene to Chromosome (Chr) 1q1.6-1.7. A (GT)14(AT)15 microsatellite was detected close to the processed pseudogene.

Animals↗
PubMed1993

Characterization of 24 porcine (dA-dC)n-(dT-dG)n microsatellites: genotyping of unrelated animals from four breeds and linkage studies.

Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P < 0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.

Alleles↗
PubMed1992

Isolation and sequencing of porcine lipoprotein lipase cDNA and its use in multiallelic restriction fragment length polymorphism detection.

Porcine lipoprotein lipase (LPL) cDNA has been cloned and sequenced. The deduced amino acid sequence shows a high degree of identity to LPL from other species, and contains the Ser/His/Asp triade characteristic of serine proteases and esterases. A repetitive element is present in the 3'-untranslated region of the cDNA. A partial cDNA covering the coding region of LPL detects three restriction fragment length polymorphisms with HindIII. This represents the first marker assigned to porcine chromosome 14.

Alleles↗
PubMed1992

DNA sequence of the skeletal muscle calcium release channel cDNA and verification of the Arg615----Cys615 mutation, associated with porcine malignant hyperthermia, in Norwegian landrace pigs.

Porcine calcium release channel (CRC) cDNA from skeletal muscle has been cloned and sequenced. The deduced amino acid sequence showed 97% identity to the corresponding rabbit and human sequences. Using oligonucleotide primers based on the nucleotide sequence, CRC cDNA fragments from seven pigs representing HALNN, HALNn and HALnn genotypes have been amplified. Sequencing and restriction digestion of the amplified cDNA confirm that the reported C----T mutation, which gives rise to Arg615----Cys615 change in the calcium release channel, is associated with the halothane sensitive allele in Norwegian Landrace pigs. The mutation may alter the reactivity of a neighbouring serine residue which is potentially phosphorylated.

Animals↗
PubMed1992

Characterization of a porcine variable number tandem repeat sequence specific for the glucosephosphate isomerase locus.

A variable number of tandem repeat from a porcine glucosephosphate isomerase intron has been isolated and sequenced. The repeat has a unit size of 39 bp, is highly conserved and is present in at least 14 copies. Flanking sequences show a sequence periodicity of 53-54 bp and some sequence homology to the 39 bp repeat. A considerable part of the genomic DNA has been lost during subcloning and is considered to be deletion prone or refractory to propagation in E. coli. The tandem repeat is locus specific and detects at least six alleles in BamHI digested porcine DNA. No homology to other tandem repeat sequences has been found.

Animals↗