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Biomedical subjects

D Atkinson

Publications and source records attributed to D Atkinson.

At least 55 records · Page 3Linked to original sources
PubMed1994

Magnetic resonance angiography.

Magnetic resonance (MR) angiography is a broad and expanding field. The technology of MR angiograms is evolving to produce higher spatial resolution, faster acquisition times, and reduced artifact. Rather than a straight, linear evolution, this progress is going forward in a number of areas inherent to the MR imaging process. Considerable progress has been demonstrated in such diverse areas as flow-sensitized radiofrequency pulses, reduced background signal with off-resonance pulses, improved vessel depiction with reduced echo times via improved hardware and reconstruction techniques, and improved display with more powerful computer algorithms. This review is a brief survey and comparison of available techniques for the visualization of blood vessels within the human body.

Humans↗
PubMed1994

Skin simulation for minor surgical procedures.

A simulated skin preparation is described which is made by bonding siliconized rubber to a latex foam base. This composite material, which simulates both the dermis/epidermis and subcutaneous fat, provides a realistic model which can be used to teach excision of skin lesions and a variety of suturing methods. We believe that this simulator is of value not only for surgeons in-training but also will allow general practitioners to improve their technical skills in performing minor surgical procedures.

Dermatologic Surgical Procedures↗
PubMed1993

Hepatic cryosurgery with and without the Bair Hugger.

Hypothermia is a significant clinical problem during hepatic cryosurgery, which at times causes the procedure to be halted until the patient's body temperature can be raised. This study examines the effects of the Bair Hugger (a warming device) on body temperature during hepatic cryosurgery. Twenty-eight cases of hepatic cryosurgery were performed without the Bair Hugger, while 44 cases included the Bair Hugger. The lowest mean temperature was significantly lower in the group without the Bair Hugger (34.2 degrees C vs. 35.3 degrees C; P < 0.0001). In addition, this group showed a significantly greater mean change in temperature during the procedure (1.81 degrees C vs. 0.73 degrees C; P < 0.0001). No patient in the Bair Hugger group reached the point of clinically significant hypothermia. In conclusion, the Bair Hugger is safe and very effective in regulating body temperature and it is an essential piece of equipment performing hepatic cryosurgery.

Cryosurgery↗
PubMed1993

Hemizygosity at the elastin locus in a developmental disorder, Williams syndrome.

Williams syndrome (WS) is a developmental disorder affecting connective tissue and the central nervous system. A common feature of WS, supravalvular aortic stenosis, is also a distinct autosomal dominant disorder caused by mutations in the elastin gene. In this study, we identified hemizygosity at the elastin locus using genetic analyses in four familial and five sporadic cases of WS. Fluorescent in situ hybridization and quantitative Southern analyses confirmed these findings, demonstrating inherited and de novo deletions of the elastin gene. These data indicate that deletions involving one elastin allele cause WS and implicate elastin hemizygosity in the pathogenesis of the disease.

Adult↗
PubMed1993

Locus heterogeneity of autosomal dominant long QT syndrome.

Autosomal dominant long QT syndrome (LQT) is an inherited disorder that causes syncope and sudden death from cardiac arrhythmias. In genetic linkage studies of seven unrelated families we mapped a gene for LQT to the short arm of chromosome 11 (11p15.5), near the Harvey ras-1 gene (H ras-1). To determine if the same locus was responsible for LQT in additional families, we performed linkage studies with DNA markers from this region (H ras-1 and MUC2). Pairwise linkage analyses resulted in logarithm of odds scores of -2.64 and -5.54 for kindreds 1977 and 1756, respectively. To exclude the possibility that rare recombination events might account for these results, we performed multipoint linkage analyses using additional markers from chromosome 11p15.5 (tyrosine hydroxylase and D11S860). Multipoint analyses excluded approximately 25.5 centiMorgans of chromosome 11p15.5 in K1756 and approximately 13 centiMorgans in K1977. These data demonstrate that the LQT gene in these kindreds is not linked to H ras-1 and suggest that mutations in at least two genes can cause LQT. While the identification of locus heterogeneity of LQT will complicate genetic diagnosis, characterization of additional LQT loci will enhance our understanding of this disorder.

Chromosome Mapping↗
PubMed1993

Effects of argon laser light, alternate source light, and cyanoacrylate fuming on DNA typing of human bloodstains.

Restriction fragment length polymorphism (RFLP) profile results were obtained from deoxyribonucleic acid (DNA) isolated from human bloodstains that had been subjected to cyanoacrylate ester ("superglue") fuming, argon ion laser light and alternate light sources. All RFLP profile results obtained from treated samples were consistent with the DNA pattern from untreated bloodstains.

Argon↗
PubMed1992

Conformational analysis of apolipoprotein A-I and E-3 based on primary sequence and circular dichroism.

The primary and secondary structure of human plasma apolipoprotein A-I and apolipoprotein E-3 have been analyzed to further our understanding of the secondary and tertiary conformation of these proteins and the structure and function of plasma lipoprotein particles. The methods used to analyze the primary sequence of these proteins used computer programs: (a) to identify repeated patterns within these proteins on the basis of conservative substitutions and similarities within the physicochemical properties of each residue; (b) for local averaging, hydrophobic moment, and Fourier analysis of the physicochemical properties; and (c) for secondary structure prediction of each protein carried out using homology, statistical, and information theory based methods. Circular dichroism was used to study purified lipid-protein complexes of each protein and quantitate the secondary structure in a lipid environment. The data from these analyses were integrated into a single secondary structure prediction to derive a model of each protein. The sequence homology within apolipoproteins A-I, E-3, and A-IV is used to derive a consensus sequence for two 11 amino acid repeating sequences in this family of proteins.

Amino Acid Sequence↗
PubMed1991

Sexual showiness and parasite load: correlations without parasite coevolutionary cycles.

Hamilton & Zuk (1982, Science 218, 384-387.) produced a model of sexual selection in which coevolutionary cycles of host and parasites generate consistently positive correlations between parent and offspring viability, and that animals choose mates for genetic disease resistance by scrutinizing characters whose full expression is dependent on health and vigour. They predicted a positive correlation between sexual showiness and parasite burden across species, and a negative correlation within a species. First, recent suggestions that interspecific correlations in the opposite direction to that indicated above are consistent with the mechanisms of Hamilton & Zuk's model are discussed. Second, it is shown that the model's predictions can be produced by heritable variation maintained by non-parasite fluctuating selection. In this case, the parasites associated with degree of sexual showiness are those able to amplify any initial heritable differences in vigour. Alternative sources of positive correlation between parent and offspring viability, which include the indirect effects of climatic change and exclude the need for host-parasite coevolutionary cycles, are also proposed.

Animals↗
PubMed1991

Linkage of a cardiac arrhythmia, the long QT syndrome, and the Harvey ras-1 gene.

Genetic factors contribute to heart disease. In this study, linkage analyses have been performed in a family that is predisposed to sudden death from cardiac arrhythmias, the long QT syndrome (LQT). A DNA marker at the Harvey ras-1 locus (H-ras-1) was linked to LQT with a logarithm of the likelihood ratio for linkage (lod score) of 16.44 at theta = 0, which confirms the genetic basis of this trait and localizes this gene to the short arm of chromosome 11. As no recombination was observed between LQT and H-ras-1, and there is a physiological rationale for its involvement in this disease, ras becomes a candidate for the disease locus.

Chromosome Mapping↗
PubMed1991

Evaluation and management of supraventricular tachycardia in children.

Emergency physicians may be called on to resuscitate acute complications in pediatric patients with congenital heart disease. Supraventricular tachycardia, with or without hemodynamic decompensation, is one of the most serious complications. We present the case of a 22-month-old boy with a history of single ventricle who presented to our institution with a history of syncope and hemodynamically stable supraventricular tachycardia. Initial attempts at pharmacologic conversion with propranolol and verapamil failed. The arrhythmia was terminated in response to an IV fluid bolus and dopamine infusion and probably resulted from a combination of anemia, hypovolemia, and impaired contractility. Appropriate evaluation and management relating to the cre of acute supraventricular tachycardia in children are discussed.

Anemia↗
PubMed1991

Consistent linkage of the long-QT syndrome to the Harvey ras-1 locus on chromosome 11.

The long-QT syndrome (LQT; Ward-Romano syndrome) is a cardiac disorder that is inherited as an autosomal dominant trait. Affected family members suffer from recurrent syncope and sudden death due to ventricular arrhythmias. Recently, we identified a DNA marker on the short arm of chromosome 11 (the Harvey ras-1 locus [H-ras-1]) that was completely linked to the LQT locus in one large family. In the study presented here, we performed linkage investigations on six new and unrelated families with LQT. The LQT locus was again completely linked to the H-ras-1 locus in all families examined, with a combined lod score of 5.25 at a recombination fraction of 0. This work confirms our previous assignment of the LQT locus to chromosome 11p and supports the hypothesis that LQT is genetically homogeneous. As no obligate recombinants were identified in either this or our previous study, the H-ras-1 protooncogene remains a candidate for the LQT disease gene. Identification of LQT families with locus homogeneity is an important step in the development of a refined genetic map of this locus and will help determine whether the H-ras-1 marker would be of general use for presymptomatic diagnosis of this potentially fatal, but treatable, disorder.

Chromosome Mapping↗