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Biomedical subjects

J S Noble

Publications and source records attributed to J S Noble.

17 recordsLinked to original sources
PubMed1998

Tracheal intubating conditions after induction with propofol, remifentanil and lignocaine.

We have studied the intubating conditions in 60 ASA I or II patients, after induction of anaesthesia with propofol 2 mg kg-1, allocated to one of the following three groups: group 1, remifentanil 1 microgram kg-1; group 2, remifentanil 1 microgram kg-1 and lignocaine 1 mg kg-1; group 3, remifentanil 2 micrograms kg-1. No neuromuscular blocking agents were administered. Intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, jaw relaxation, position of vocal cords, degree of coughing and limb movement. Overall intubating conditions were acceptable in 35% of patients in group 1, 100% of patients in group 2 and 85% of patients in group 3. There was a statistically significant drop in blood pressure after induction in groups 2 and 3, and two patients in each group required ephedrine 6 mg i.v. boluses, as dictated by the intervention criteria (mean arterial pressure fall > 25% from baseline). Similarly, there was a drop in heart rate in groups 2 and 3, but this did not reach statistical or clinical significance, and no patient required atropine.

Adolescent↗
PubMed1997

Identification of an arginine452 to histidine substitution in the erythroid 5-aminolaevulinate synthetase gene in a large pedigree with X-linked hereditary sideroblastic anaemia.

The coding region of the erythroid 5-aminolaevulinate synthetase gene (ALAS2) from a large pedigree with pyridoxine-responsive X-linked hereditary sideroblastic anaemia was examined for mutations. In three affected males from this pedigree, single strand conformational polymorphism (SSCP) analysis showed anomalous migration of a PCR product spanning exon 9. Sequencing of amplified genomic DNA from one of these affected males revealed a guanine to adenine transition at nucleotide 1407 of the cDNA sequence in exon 9 of the gene. This mutation results in the loss of an HhaI restriction enzyme digest site. An HhaI digest assay demonstrated the presence of this mutation in other affected males but not in unaffected males and unrelated individuals. The point mutation results in an arginine to histidine substitution at amino acid residue 452. The arginine residue is conserved in both the erythroid and housekeeping ALAS genes in all known vertebrate sequences. This arginine is located in the middle of a predicted alpha-helix.

5-Aminolevulinate Synthetase↗
PubMed1995

Linkage analysis of a large pedigree with hereditary sideroblastic anaemia.

A large pedigree showing a history of pyridoxine responsive X linked sideroblastic anaemia was screened with several polymorphic DNA markers from the X chromosome. Linkage analysis between each marker and disease status was performed, giving a maximum two point lod score of 3.64 at zero recombination with the microsatellite marker PGK1P1 at Xq11.2-12. Close linkage to PGK at Xq13.3, one of the candidate regions for X linked sideroblastic anaemia, was excluded. Linkage to DNA markers distal to PGK and at Xp21 was also excluded. Multipoint linkage analysis was performed with markers located between Xq11.2-21. The maximum map specific lod score obtained was 3.56 at PGK1P1 (Xq11.2-12). Linkage remained significant over the interval 20 cM proximal to PGK1P1 and 5 cM distal to PGK1P1, with definite exclusion around the PGK locus. The most likely location of the gene involved in sideroblastic anaemia in this pedigree is therefore within the pericentromeric region of the X chromosome. This region includes the erythroid 5-aminolaevulinate synthetase gene of the haem synthesis pathway, which is a candidate gene for X linked sideroblastic anaemia located at Xp11.21.

Alleles↗
PubMed1995

Failure of total shoulder arthroplasty: why does it occur?

From a historical perspective, shoulder arthroplasty has evolved significantly from its inception. Much like arthroplasty of the lower extremities, shoulder implant design had its roots in a constrained device. Unfortunately, the inherently high loads that these devices generated across the implant articulation and the glenoid bone interface resulted in an unacceptably high failure rate. Beginning with Neer's original hemiarthroplasty of the 1950s and the more recent implant designs, there has been a strong trend toward less constraint and a greater emphasis on soft tissue preservation in shoulder replacement. In the ideal arthroplasty patient with an intact rotator cuff and a stable, yet degenerative, glenohumeral joint, arthroplasty invariably yields good-to-excellent results 90% of the time. However, owing to the enormous functional range of motion of the joint and its inherent dependence on soft tissues for both stability and motion, there are many areas for potential complications. This article addresses the etiology, recognition, and treatment of these problems.

Humans↗
PubMed1994

Automated analysis of multiplex microsatellites.

The use of automated DNA fragment analysis with the Applied Biosystems 672 Genescanner system was evaluated in a routine diagnostic setting. The aim of the study was to compare automated fragment detection and analysis with conventional methods. For cystic fibrosis analysis the delta F508 mutation in exon 10 of the cystic fibrosis transmembrane regulator (CFTR) gene was multiplexed with two intragenic microsatellites. The analysis of the Prader-Willi/Angelman region of chromosome 15 used a panel of five microsatellites. For dystrophin, seven microsatellites covering the entire dystrophin gene were co-amplified. Automated analysis was faster and more accurate than analysis using radiolabelled products with sequencing gels, although some inconsistencies in the sizing of microsatellite alleles were seen.

Angelman Syndrome↗
PubMed1992

Isolation and sequencing of CA/GT repeat microsatellites from chromosomal libraries without subcloning.

A method for the isolation of (CA)n microsatellites from chromosome-specific genomic libraries is described. Clones were first screened using a polynucleotide CA/GT probe. Those shown to contain CA repeats were plaque purified and either subcloned or the insert amplified directly using vector primers. Polymerase chain reaction products were then used to directly sequence the regions flanking CA repeats by using biotinylated primers that amplify cloned inserts outward from CA repeat containing regions of DNA to vector primers. This method provides rapid access to microsatellites from chromosomes or chromosome regions of interest.

Alleles↗
PubMed1991

The effects of graft tensioning on the laxity and kinematics of the anterior cruciate ligament reconstructed knee.

An in vitro study of eight cadaveric knees was conducted to investigate the effect of initial graft tension on the laxity and full three-dimensional kinematics of the anterior cruciate ligament reconstructed knee. A parallel strand, prototype, expanded polytetrafluoroethylene graft (W. L. Gore and Associates, Flagstaff, AZ, U.S.A.) was used. The graft was placed in the over-the-top position with initial tensions of 18, 36, 54, 72, and 90 N applied with the knee in full extension or at 30 degrees of flexion. The motion of the tibia relative to the femur was measured by a 6 degrees-of-freedom spatial linkage, and the applied forces and moments, the quadriceps force, and the graft tension were measured by load cells. Near normal anterior laxity in the Lachman test was restored with all the tested initial graft tensions. However, over constraint, posterior, lateral, and external tibial subluxation, and abnormalities in joint stiffness developed as the initial graft tension increased. Graft tension-related posterior tibial subluxation resulted in an increase in quadriceps force needed to achieve full extension.

Aged↗
PubMed1991

An appreciation of posterior instability of the shoulder.

Fortunately, posterior instability of the shoulder is a relatively uncommon occurrence in the athlete. Acute traumatic posterior dislocations can be readily managed by conservative measures. Recurrent posterior subluxation, however, represents a more challenging problem for the orthopedic surgeon. As has been discussed, most patients with this disorder respond to nonsurgical treatment including physical therapy and modification of the offending activities. Should these modalities fail, operative treatment may be necessary. Careful assessment of the patient to rule out the associated presence of excessive ligamentous laxity or a voluntary component to the instability is mandatory. Pain is clearly the principal indicator for surgical treatment. Painless subluxation, either voluntary or involuntary, should first be treated conservatively. The surgical options discussed in this article range from simple soft-tissue repair to more complex osteotomies with combined capsular plication. It is important that the procedure be appropriate to the pathology. We do not believe that one technique alone can address all variants of posterior instability. Most instances of recurrent posterior subluxation represent unidirectional instability in patients with otherwise normal bony morphology. In these patients, a posterior capsulorrhaphy combined with appropriate immobilization should be effective. In select instances, when either excessive glenoid retroversion or deficiency is encountered, a glenoid osteotomy and posterior capsulorrhaphy have proved successful. This technique, more than any other, carries a number of potential technical pitfalls and should be employed cautiously. Multidirectional posterior instability, now a well-recognized entity, requires a different surgical approach--the capsular shift. Designed to address the inferior redundancy, as well as posterior laxity, this procedure is applicable to the multidirectional posterior subluxator. In conclusion, posterior instability of the athlete's shoulder is an increasingly recognized entity. Most instances are amenable to nonsurgical care. Should surgical treatment be necessary, optimal results may be achieved by careful attention to patient assessment, instability categorization, determination of the presence of ligamentous laxity, and appropriate surgical technique.

Humans↗
PubMed1979

Isolation and translation in vitro of poly(A)+RNA from the free-living nematode Panagrellus silusiae.

Polysomal RNA was isolated from the free-living nematode Panagrellus silusiae. Passage of this RNA through a cellulose column resulted in the fractionation of the input RNA into poly(A)-RNA (ca. 97.5% of the total) and poly(A)+ RNA (ca. 2.5% of the total). RNase digestion, followed by polyacrylamide gel electrophoresis, revealed that the poly(A)+ RNA contained poly(A) tracts that ranged from 75 to 104 nucleotides in length with a mean value of about 90 residues. There was no evidence of poly(A) sequences in the poly(A)- RNA fraction. Poly(A)+ RNA gave a 25- to 50-fold stimulation (over background) of amino acid incorporation in the wheat germ cell-free protein-synthesizing system. At least 26 proteins were evident after electrophoresis in cylindrical sodium dodecyl sulfate-polyacrylamide gels. Poly(A)-RNA was capable of stimulating protein synthesis in vitro with about five discrete proteins being produced. In summary, the properties of mRNA from a simple organism such as P. silusiae are very similar to those of more complex eukaryotes.

Animals↗
PubMed1976

Relative ribosomal RNA cistron multiplicity in oocytes and postembryonic stages of the eutelic nematode Panagrellus silusiae.

The number of ribosomal RNA cistrons has been measured in the total DNA extracted from L2 juvenile and adult stages of the free-living nematode Panagrellus silusiae. Saturation hybridization studies with homologous rRNA indicate that both stages have about 275 ribosomal genes per haploid equivalent. Using homologous 125I-labelled rRNA for in situ hybridization, the mean number of silver grains per DNA content for oocyte, hypodermis and gut nuclei was similar. The mean DNA contents of maturing oocyte, hypodermis and gut nuclei are about 20C, 2C, and 10C respectively. We conclude that rDNA amplication alone is insufficient to account for the variation in DNA content of oocytes and that postembryonic development in this eutelic organism occurs without a significant differential increase in the number of ribosomal cistrons per worm.

Animals↗
PubMed1975

Properties and synthesis of ribosomal RNA in the free-living nematode Panagrellus silusiae.

The normal S values of ribosomes and ribosomal subunits extracted from the free-living nematode. Panagrellus silusiae are similar to those of other eukaryotic organisms. Upon heating (70 degrees C, 15 min) a 5.5-S RNA is released from the larger ribosomal RNA (27 S; 1.40-10(6) daltons). Unlike other protostomes, however, the 27-S rRNA does not dissociate in an orderly manner to yield 18-S components. The electrophoretic mobility of the small ribosomal RNA species (18 S; 0.72-10(6) daltons) is unaltered by heat treatment. The base composition of both Panagrellus rRNA species has a 51% G+C content. Labelling worms with either [Me-3H] methionine or [14C] uridine at various stages of postembryonic development and subsequent analysis of the extracted RNA revealed eight radioactive fractions, two of which were the mature ribosomal RNAs. From both the time sequence of appearance of the eight RNA species and the relative degree of methylation of the various RNA fractions two maturation pathways for ribosomal RNA processing were deduced. A 37-S (3.6-10(6) daltons) RNA is the precursor to both 27-S and 18-S RNA. During processing about two-fifths of the original transcriptional unit is lost. In this organism the "transcribed spacer" regions may be methylated although alternate interpretations have not been precluded.

Cell Fractionation↗
PubMedDate not supplied

A rapid PCR-based method to distinguish between fetal and maternal cells in chorionic biopsies using microsatellite polymorphisms.

In some chorionic villus biopsy (CVB) cases the fetal/maternal origin of the tissue obtained is uncertain. An approach which only requires small amounts of CVB tissue to establish its origin is described. Since it is only the samples typed as female that could be either fetal or maternal, a paternal X chromosome contribution is sought by using highly polymorphic X-linked microsatellites.

Alleles↗
PubMedDate not supplied

Severely displaced proximal humeral epiphyseal fractures: a follow-up study.

Forty-eight patients with severely displaced proximal humeral epiphyseal fractures were reviewed. Twenty-one patients were followed up for an average of 9 years after injury with a personal interview, examination, and radiographs. Average age was 14.1 years, half of whom were age 15 years or older. Initial head-shaft displacement averaged 80%, and 31 fractures were displaced by > or = 80%. All underwent attempted closed reduction. Radiographs for all except three were sufficient to judge the adequacy of reduction. Twenty-six of 45 attempted closed-reductions failed to improve displacement significantly. Nine patients underwent operative treatment, and the remainder had a closed reduction. In the operative group, complications occurred in three of nine patients. No complications occurred in the nonoperative group. No patients seen at late follow-up identified any activity or employment restrictions as a result of their injuries. Several patients incurred humeral shortening or imperfect radiographic remodeling, but this did not correlate with clinical outcome. Comparing the operative complications with the excellent late results after nonoperative treatment in this series supports previous recommendations to avoid operative intervention with few exceptions. The magnitude of displacement alone does not appear to justify operative treatment.

Adolescent↗