Genotype and secretory response in cystic fibrosis.
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Chlorides↗
Biomedical subjects
C J Taylor
Publications and source records attributed to C J Taylor.
Bending and fracture of the femoral component in cemented total hip replacement.
A computer method was used to make 41 measurements on the geometry of insertion of the femoral component in 200 Charnley total hip replacements. Surgery had been performed at least 12 years before, giving results which were classified as: success (90); fracture (56); or loose (54), according to rigid selection criteria. Fracture was associated with heavier patients in which there was poor proximal fixation of the femoral component but adequate distal fixation. Stems with a medial disposition proximally were more common in the fracture group than in the successful or loose groups. Sequential measurements of bending and subsequent fracture were made on the follow-up radiographs of 24 of the 200 cases (6 fracture and 18 successful). These measurements allowed bending to be detected at an earlier stage than by simple inspection of the radiographs.
Aged↗
Aseptic loosening of the femoral component in cemented total hip replacement.
The purpose of this study was to identify factors which predispose to aseptic loosening of the femoral component in cemented total hip replacement. Its design was based on rigid selection criteria, so that successful and loose replacements which employed the same surgical technique were compared. Measurements of patient anatomy and of the insertion of the femoral component were made, by an accurate computer technique, on initial post-operative radiographs. Loosening was associated with heavier patients with a wider medullary canal which was flared proximally. This difference in anatomy led to differing distributions of cement in the successful and loose replacements. Medial cement-bone demarcation, at the mid-stem level, was also associated with loosening. These findings indicate the importance of optimizing the size of the prosthesis with respect to the femoral morphology.
Bone Cements↗
A new strategy for the assessment of viable myocardium and regional myocardial blood flow using 15O-water and dynamic positron emission tomography.
BACKGROUND: We have developed a new measure of myocardial viability, the water-perfusable tissue index (PTI), which is calculated from transmission, C15O, and H2(15)O positron emission tomography (PET) data sets. It is defined as the proportion of the total anatomical tissue within a given region of interest (ROI) that is capable of rapidly exchanging water and has units g (perfusable tissue)/g (total anatomical tissue). The aim of this study was to assess the prognostic value of PTI in predicting improvement in regional wall motion after successful thrombolysis for acute myocardial infarction (AMI) and to measure the myocardial blood flow to the perfusable tissue (MBFp, ml/min/g [perfusable tissue]). Furthermore, PTI was compared with 18FDG metabolic imaging in patients with old myocardial infarction (OMI). METHODS AND RESULTS: PET scans were performed in healthy volunteers (group 1, n = 8), patients with OMI (group 2, n = 15), and in patients who were successfully thrombolysed after an AMI (group 3, n = 11). Systolic wall thickening was measured by two-dimensional echocardiography within 2-4 days of AMI and after 4 months to assess contractile recovery. In the healthy volunteers, MBFp was 0.95 +/- 0.13 ml/min/g (perfusable tissue). PTI in these regions was 1.08 +/- 0.07 g (perfusable tissue)/g (total anatomical tissue), which was consistent with all normal myocardium being perfusable by water. In the OMI group, the ratio of the relative 18FDG activity to the relative MBFp defect (metabolism-flow ratio) was calculated for each asynergic segment. Regions in which the metabolism-flow ratio was greater than or equal to 1.20 were considered reversibly injured, whereas those in which the ratio was less than 1.20 were deemed irreversibly injured. PTI in the former group of regions (n = 9) was 0.75 +/- 0.14 g (perfusable tissue)/g (total anatomical tissue) and was significantly higher than in irreversibly injured regions (n = 6) (0.53 +/- 0.12 g [perfusable tissue]/g [total anatomical tissue], p less than 0.01). Values of MBFp were similar in these segments. Seven of 12 segments in the AMI patients showed improved systolic wall thickening on follow-up. PTI in these recovery segments was 0.88 +/- 0.10 g (perfusable tissue)/g (total anatomical tissue) (p = NS versus control). PTI in the nonrecovery regions was 0.53 +/- 0.11 g (perfusable tissue)/g (total anatomical tissue), which was similar to the segments in group 2 in which 18FDG uptake was absent. MBFp was similar in both the recovery and nonrecovery segments in the subacute phase. CONCLUSIONS: These data indicate that PTI may be a good prognostic indicator for the recovery of contractile function after successful thrombolysis and show that myocardial viability may be assessed by PET without metabolic imaging.
Adult↗
[Evaluation of a peptide preparation (milk) in the care of infants with various gastrointestinal intolerances].
The use of an enteral peptide feed based on hydrolysed whey protein (Pepti Junior, Cow and Gate/Nutricia Ltd.) was evaluated in 17 patients with complex GIT intolerance. Nine post surgical neonates were weaned onto the feed either following a period of parenteral nutrition (8) or after demonstrating intolerance of both breast milk and a lactose-free soy based formula. Eight infants admitted to a gastroenterology ward with multiple protein intolerances were also studied. Patients were fed to their nutritional requirements with the milk containing/100 ml; 67 kcal (280 kJ), 2.0 g protein, 3.7 g fat (50% MCT, 50% vegetable oil) and 6.7 g carbohydrate (98% maltodextrins). Patients were maintained on the feed for 7-45 weeks (mean 21 weeks). Full nutritional support was possible with the new formula in all but 2 children who had jejunostomies; in these patients > 50% of nutritional requirement were supplied by the enteral feed. All patients gained weight (mean 0.16 kg/week) (SD 0.09). With the exception of subclinical selenium deficiency, no abnormalities of haematological, biochemical or vitamin states were observed. Post prandial plasma amino-acid concentrations were within acceptable limits and similar to those reported on standard whey based infant formulae. The feed appeared well tolerated in infants with GIT intolerances with no major complications in long term usage.
Evaluation Studies as Topic↗
Association of autoimmunity and cicatricial pemphigoid: is there an immunogenetic basis?
A group of 34 patients with cicatricial pemphigoid was investigated for the presence of autoimmune disorders. Thirty-two percent of patients had autoimmune disease compared with 7% in the control population, a highly significant difference (p less than 0.002). Circulating autoantibodies were also significantly more common in patients (p less than 0.05). Twenty-four patients with cicatricial pemphigoid were typed for HLA. A statistically significant increase in the frequency of DR4 and DQw3 antigens was observed in these patients. These findings suggest a possible genetic basis for the autoimmune association and predisposition for development of cicatricial pemphigoid.
Adolescent↗
Production and characterization of human monoclonal lymphocytotoxic autoantibodies from a renal dialysis patient.
We have produced human monoclonal lymphocytotoxic autoantibodies from a renal dialysis patient by the generation of a mouse/human heterohybridoma. The antibodies are of the IgM class and react with the patient's autologous cells, the B-lymphoblastoid cell line producing the antibody, normal T and B lymphocytes, B cells from chronic lymphatic leukemia patients (CLL cells), and the autoantibody-sensitive cell line K562. Screening of the monoclonal antibodies (mAb) against panels of normal T and B cells and CLL cells demonstrated that different reactivity profiles could be generated at different dilutions of the mAb. These profiles were identical to those seen with autoantibodies from different renal patients and this suggests that these profiles do not imply different antibody specificities but differing target cell sensitivity. Reactivity profiles seen in the fluorescence binding assays suggest that the target cell sensitivity is dictated not by antigen density alone but also by antibody/antigen affinity. The results from studies of enzyme treatment of target cells and lectin inhibition of the molecular specificity suggest that the autoantibodies are polyreactive, capable of binding sialic acid-dependent epitopes and other negatively-charged cell surface molecules.
Animals↗
Measurement of intracellular mediators in enterocytes isolated from jejunal biopsy specimens of control and cystic fibrosis patients.
A method that maximises the yield of viable enterocytes has been developed for the isolation of enterocytes from human jejunal biopsy specimens. These enterocytes have been used to study the values of intracellular free calcium and the rises in adenosine 3'5'-cyclic monophosphate (cAMP) induced by secretagogues in normal and cystic fibrosis cells. Basal intracellular free calcium of cystic fibrosis enterocytes, measured fluorimetrically with fura-2, was within the range of the basal intracellular free calcium of non-cystic fibrosis enterocytes (cystic fibrosis 263 nmol/l; non-cystic fibrosis 287 nmol/l). Changes in intracellular free calcium were observed after exposure to ionomycin: a 100 nmol/l solution induced a 2.5 fold increase in intracellular free calcium in the cystic fibrosis enterocytes and a 2.2 fold increase in the intracellular free calcium concentration of the non-cystic fibrosis enterocytes. Basal cAMP values were not significantly different between cystic fibrosis and non-cystic fibrosis enterocytes (cystic fibrosis 575 fmol/100,000 cells; non-cystic fibrosis 716 fmol/100,000 cells, p greater than 0.05) and the enterocyte cAMP value increased in response to stimulation with prostaglandin E2 (7 mumol/l) (cystic fibrosis 2.2 fold increase over basal, p less than 0.05; non-cystic fibrosis 1.9 fold stimulation over basal, p less than 0.05) and vasoactive intestinal polypeptide (100 nmol/l) (cystic fibrosis 7.1 fold increase over basal, p less than 0.05; non-cystic fibrosis 5.8 fold increase over basal, p less than 0.05). There was no significant difference in the magnitude of the response between cystic fibrosis and non-cystic fibrosis enterocytes (p greater than 0.05). These results indicate that the cystic fibrosis defect in the small intestine, as in other affected epithelia, seems to be distal to the production of second messengers. The small intestine is therefore an appropriate model in which to study the biochemical defect in cystic fibrosis.
Animals↗
Failure of cholinergic stimulation to induce a secretory response from the rectal mucosa in cystic fibrosis.
The secretory response to cholinergic stimulation was investigated in rectal biopsy specimens from children with cystic fibrosis and a control group using a modified Ussing chamber technique. Acetylcholine (10(-3) mol/l) increased the short circuit current in 12 control specimens by mean (SEM) 83.0 (16.4) microA/cm2, but samples from five children with cystic fibrosis failed to exhibit such a response (-1.4 (3.2) microA/cm2). Amiloride (10(-4) mol/l), which will inhibit electrogenic sodium absorption in viable tissues, caused similar reductions in the short circuit current of both control and cystic fibrosis tissues (control = -37.7 (7.7) microA/cm2; cystic fibrosis = -44.0 (9.3) microA/cm2). Thus, the failure of chloride secretion observed in the small intestine also exists in the rectal mucosa. This observation could be used both to aid diagnosis and to study the basic defect.
Acetylcholine↗
Open access exercise electrocardiography: a service to improve management of ischaemic heart disease by general practitioners.
An initial study of the use of open access exercise electrocardiography by general practitioners (GPs) in South East Kent showed that patient selection and interpretation of test results was frequently incorrect. After issuing guidelines, modifying the request form and instituting registrar review of all requests, significant improvements in both referral pattern, result interpretation and patient management have resulted. Forty-nine GPs requested 110 exercise tests during 1988/89. Twelve per cent were not undertaken after discussion with the referring practitioner. Eighty-four per cent of those tested would have been referred to the district general hospital cardiology outpatient department in the absence of open access exercise electrocardiography service. Six per cent of patients were referred directly for invasive investigation. Thirty-five per cent were referred to the district general hospital cardiology outpatient department, whilst 42% were spared hospital referral based on the result of the investigation. Better use of the modified service was suggested by: referral of fewer patients with non-cardiac chest pains (P = 0.002); more patients with a moderate pre-test probability of ischaemic heart disease (P less than 0.05); fewer inappropriate requests (P less than 0.01); and fewer inappropriately undertaken tests (P less than 0.001) than in the previous study. All patients with strongly positive test results were appropriately managed. Open access exercise electrocardiography in the format investigated is potentially a cost-effective and useful tool to improve diagnosis and management of heart disease by GPs.
Adolescent↗
Measurement of hip prostheses using image analysis. The maxima hip technique.
A computer-based image analysis system has been developed as a research tool in total hip replacement. The system has been programmed to take multiple measurements from coronal plane radiographs. Poor quality radiographic images can be enhanced and standardised. The measurements which can be obtained include stem subsidence, cup migration, cup wear, and stem loosening. Reproducibility and accuracy were +/- 0.01 mm and +/- 0.5 mm respectively. The present application is in retrospective research, but prospective monitoring of radiographs is planned.
Hip Joint↗
Computerised image analysis of split-drop micropuncture data.
A technique is described for rapid and reproducible analysis of split-drop micropuncture sequences recorded on film. Automatic identification of the droplet menisci in each cine frame, and subsequent evaluation is performed by a computerised T.V. image analysis system. In comparison with a more conventional technique, the improvement in reproducibility of the analysis is achieved without loss of accuracy and is accompanied by a three fold increase in speed.
Animals↗
Quantitative cytophotometry and image analysis with the Magiscan.
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Autoanalysis↗
A grief experience in juvenile diabetes.
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Adaptation, Psychological↗
A blackboard architecture for automating cephalometric analysis.
This paper describes a principled attempt to use artificial intelligence methodologies for interpretation of lateral skull X-ray images. Lateral skull X-ray images are routinely used in cephalometric analysis to provide quantitative measurements useful to clinical orthodontists. Manual and interactive methods of analysis are known to be error-prone, and time-consuming. Previous attempts have been made to automate this analysis, using conventional algorithmic approaches. Unfortunately such systems typically fail to capture the expertise and adaptability required to cope with the variability in biological structure and X-ray image quality found in cephalograms. The present system makes use of a blackboard architecture and multiple knowledge sources within an integrated model-based system. A data-gathering system allows models of feature appearance and location to be built from examples. Blackboard and task control modules allow specific knowledge-based modules to act on information available to the blackboard. Knowledge-based modules include location hypothesis, intelligent segmentation, and constraint propagation systems. Results from a working experimental system are given, and compare favourably with previous algorithmic solutions.
Artificial Intelligence↗