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Biomedical subjects

P Butler

Publications and source records attributed to P Butler.

At least 109 records · Page 6Linked to original sources
PubMed1987

Arterial PaO2 and PaCO2 influence seizure duration in dogs receiving electroconvulsive therapy.

The influence of arterial O2 and CO2 tensions on electroconvulsive seizure duration was investigated in five mongrel dogs under consistent anaesthetic conditions. Seizure durations were measured in a randomized protocol of nine possible combinations of arterial gas tension spanning increased, normal or decreased levels of PaO2 and PaCO2. Seizure duration was directly related to PaO2 (p less than 0.00001) and inversely related to PaCO2 (p less than 0.0001). A significant synergism was evident at the extremes of PaO2 and PaCO2, with seizure duration being greater than predicted for hyperoxia-hypocapnia and hypoxia-hypercapnia and shorter than predicted for hypoxia-hypocapnia and hyperoxia-hypercapnia. We conclude that arterial gas tensions strongly influence ECT-induced seizure duration and through this may influence the therapeutic efficacy of electroconvulsive therapy.

Animals↗
PubMed1987

The incidence of craniocervical bony anomalies in the adult Chiari malformation.

Detailed linear, angular and surface area measurements were undertaken on the lateral skull radiographs of 32 patients with proven idiopathic adult Chiari type 1 malformation. Basal angles were larger, the clivus was shorter and Klaus' index was reduced in patients compared to normal controls. The size of the posterior fossa was smaller in patients than in controls. By discriminant analysis of the skull X-ray data it was possible to identify correctly two thirds of patients as belonging to the patient group. The findings indicate that craniocervical bony anomalies in the adult Chiari malformation are commoner than was previously realised, and they support the view that tonsillar herniation in these patients results from bony occipital dysplasia.

Adolescent↗
PubMed1987

Digital subtraction angiography (DSA): a neurosurgical perspective.

The purpose of this article is to review the contribution of DSA to neurosurgical practice and to outline its advantages and limitations compared to conventional film-screen angiography. DSA is a technique whereby electronic subtraction allows the near instantaneous demonstration of vascular anatomy essentially free of bony detail. Because DSA possesses a high degree of contrast sensitivity, arterial images can be produced after an intravenous injection of contrast medium as well as by selective arterial catheterisation.

Adult↗
PubMed1986

Carotid ligation: what happens in the long term?

The authors reviewed a consecutive series of 115 patients who underwent common carotid ligation during the period 1954-1984. Average follow-up was 10 years. Seventy-three (63%) patients presented following a subarachnoid haemorrhage (SAH) and 42 (36%) presented with the mass effect of an unruptured aneurysm. Thirty-nine (34%) patients were lost to follow-up of whom 27 had had a previous SAH. Forty-six (63%) of the 73 patients traced had suffered a SAH and amongst this group, 11 patients (24%) died from a proven or suspected recurrent haemorrhage within 10 years of ligation. The fatal recurrent haemorrhage rate was, therefore, 2.4%/year. Thirty (71%) of the 42 patients who presented with unruptured aneurysms were traced. Seven of these (23%) died: two following haemorrhage, 1 year and 16 years after carotid ligation and three patients died as a direct consequence of carotid ligation. Check angiographic studies were available for 55 patients following carotid ligation, a mean of 8.4 years after the procedure. Thirteen were conventional angiograms and 42 were intravenous angiograms obtained using the digital subtraction technique. Seventy-six per cent of the aneurysms visualised on the initial studies were either smaller or had apparently disappeared. Only four new aneurysms were detected and in two of these instances, the initial angiographic studies had been incomplete. The authors conclude that the annual rate of fatal recurrent haemorrhage from an intracranial aneurysm following common carotid ligation is of a similar magnitude to that of the natural history of conservatively managed ruptured intracranial aneurysms. Moreover, carotid ligation apparently does not prevent haemorrhage from a previously unruptured aneurysm and the procedure appears to carry a significant morbidity and mortality, even in patients with an unruptured aneurysm.

Adult↗
PubMed1986

Intravenous digital subtraction angiography.

Intravenous digital subtraction angiography (ivDSA) is a method whereby arterial images are produced following a peripheral or central venous injection of contrast medium. It is a safe and relatively simple procedure to undertake and is becoming more widely available. The purpose of this article is to review its clinical applications, its advantages and limitations.

Angiography↗
PubMed1985

The relation of preoperative coagulation findings to diagnosis, blood usage, and survival in adult liver transplantation.

A group of 70 adults with end-stage liver disease received 87 homologous liver transplants from 7/11/81 and 7/11/83. The recipients fell into the following diagnostic categories: postnecrotic cirrhosis (PNC) in 22, primary biliary cirrhosis (PBC) in 18, cancer or neoplasia (CA) in 11, sclerosing cholangitis (SC) in 8 and miscellaneous (MISC) in 11. Survival for six months or longer was 46%: survival by group was PBC = 67%, CA = 55%, PNC = 45%, SC = 25%, and MISC = 18%. Preoperative coagulation profiles were evaluated on 64 of the 70 first transplant patients by assigning a score derived from one point per abnormality in each of 8 tests. Mean coagulation abnormality scores (CAS) were strikingly elevated in the PNC and MISC groups. Mean intraoperative blood product usage was 43 units of RBCs, 40 units of fresh frozen plasma (FFP), 21 units of platelets, and 9 bags of cryoprecipitate. Direct correlations were found between CAS and RBC usage (+0.454, P = less than .001), CAS, and survival of 6 months or longer (-0.281, P = less than .02), and RBC usage and survival (-0.408, P = less than .001). These findings indicate that the degree of coagulation abnormality and the type of liver disease may be predictive of intraoperative blood usage and survival in liver transplantation in adults.

Adolescent↗
PubMed1984

Mobile domains in ribosomes revealed by proton nuclear magnetic resonance.

Ribosomes and subunits from eukaryotic and prokaryotic sources were studied by high-resolution proton magnetic-resonance spectroscopy. If all ribosomal components are firmly bound within the particle, then only broad spectra would be expected. However, relatively sharp resonances were found both in ribosomal subunits and in 70 or 80 S ribosomes. The regions of these mobile protein domains have been partially assigned in Escherichia coli ribosomes. Large and small ribosomal subunits were treated to remove selectively proteins L7/12 and S1, respectively. Sharp proton magnetic resonance spectra were not observed for the stripped large subunit showing that proteins L7/12 comprise the flexible protein region and that there is little other flexibility in the stripped subunit. Complete removal of S1 from the small subunit greatly reduced but did not abolish the sharp protein resonance peaks, indicating that protein S1 contains a substantial flexible component but that other flexible components remain in the stripped small subunit. Evidence for generality of these features of ribosome organization is provided by similar studies on ribosomes from eukaryotic sources.

Animals↗
PubMed1984

Physiological cost index of walking for normal children and its use as an indicator of physical handicap.

Seventy-two normal children aged between three and 12 years were assessed to establish their walking function. Speed of walking and heart rate were monitored continuously, both barefoot and in shoes, over eight consecutive lengths of a 25m walkway. Since heart rate is affected by speed, the physiological cost index (PCI)--which combines the two parameters--was calculated for each child, both barefoot and in shoes. Speed tends to increase and walking heart rate to decrease with age. However, resting heart rate also decreases with age, so the PCI has the same range for all ages. The mean PCI in shoes was 0.4 and barefoot was 0.38. The PCI for children with pathological gait is appreciably greater than that for normal children, so the PCI is a valuable quantitative indicator of the level of handicap.

Child↗
PubMed1983

Direct cross-links between initiation factors 1, 2, and 3 and ribosomal proteins promoted by 2-iminothiolane.

Complexes were prepared containing 30S ribosomal subunits from Escherichia coli and the three initiation factors IF1, IF2, and IF3. In different experiments, each of the factors was radiolabeled with the others unlabeled. The complexes were allowed to react with 2-iminothiolane and then oxidized to promote the formation of intermolecular disulfide bonds, some of which were between factors and ribosomal proteins. Each of the labeled factors becomes covalently cross-linked to the complex as judged by its failure to dissociate when centrifuged in a sucrose gradient containing a high salt concentration. Proteins from the complexes were extracted and analyzed on two-dimensional polyacrylamide gels by nonequilibrium isoelectric focusing and sodium dodecyl sulfate gel electrophoresis. Spots corresponding to cross-linked dimers that contained initiation factors, as indicated on autoradiographs, were cut out and analyzed further. The following cross-linked dimers between factors and ribosomal proteins were identified: IF1-S12, IF1-S18, IF2-S13, IF3-S7, IF3-S11, IF3-S13, and IF3-S19. Cross-links between factors IF1-IF2 and IF3-IF2 were also identified. A model integrating these findings with others on the protein topography of the ribosome is presented.

Binding Sites↗