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Biomedical subjects

C J Taylor

Publications and source records attributed to C J Taylor.

At least 109 records · Page 6Linked to original sources
PubMed1994

Structure of the O9 antigen from Burkholderia (Pseudomonas) cepacia.

The O9 antigen of Burkholderia (Pseudomonas) cepacia has the following disaccharide repeating-unit: -->4)-alpha-D-Glcp-(1-->3)-alpha-L-Rhap-(1--> The same unit is present in the O antigens of Serratia marcescens strain S1254 and serogroup O4 (predominantly acetylated at O-2 of rhamnose in the latter case).

Burkholderia cepacia↗
PubMed1994

Pancreatitis in patients with organic acidemias.

STUDY OBJECTIVE: The discovery of pancreatitis in two children with methylmalonic acidemia led us to review the experience with pancreatitis in a large number of patients with organic acidemias to determine whether pancreatitis is an important complication of these disorders. DESIGN: Case series. SETTING: Pediatric metabolism services at five tertiary care centers. PATIENTS: Records of all patients with organic acidemias followed at the five institutions during the past 10 years were reviewed. Pancreatitis was recognized by symptoms and laboratory findings and confirmed by imaging studies, surgery, or autopsy. At three institutions all cases of pancreatitis in children younger than 10 years were reviewed. MEASUREMENTS AND RESULTS: Nine children with pancreatitis (seven with acute and two with chronic cases) were identified among 108 children with branched-chain organic acidemias. They ranged in age from 13 months to 9 years. Five had methylmalonic acidemia, three had isovaleric acidemia, and one had maple syrup urine disease. There were three deaths; acute hemorrhagic pancreatitis occurred in two children, and chronic pancreatitis was found at autopsy in a third. All three patients with isovaleric acidemia and pancreatitis were identified after the occurrence of pancreatitis. The survey of pancreatitis at three institutions found 57 other patients (none with an inborn error) in addition to three patients with inborn errors included in this study. CONCLUSIONS: Acute or chronic pancreatitis may complicate branched-chain organic acidemias and must be considered in the assessment of patients with these disorders who have acute clinical deterioration and vomiting, abdominal pain, encephalopathy or shock, or milder symptoms. Conversely, an inborn error of organic acid metabolism should be considered in children with pancreatitis of unknown origin.

Acute Disease↗
PubMed1994

A comparison of the backgrounds of first time and repeated overdose patients.

This study examines the differences between two groups of parasuicide patients: 'first-timers' (patients admitted to hospital following their first overdose) and 'repeaters' (patients admitted with an overdose who had made at least one previous suicide attempt). The two patient groups were compared for factors known to increase the risk of parasuicide as well as for the experience of self-reported past sexual abuse and for symptoms of post traumatic stress disorder (PTSD). Out of a total of 100 patients interviewed, seven (15%) of first-timers gave a history of sexual abuse and complained of an average of 0.55 symptoms of PTSD. Among repeaters, 28 (53%) gave a history of sexual abuse and complained of an average of 1.84 symptoms of PTSD. Both results were statistically significant at P < 0.001.

Adolescent↗
PubMed1994

Loperamide inhibits the enhanced intestinal glucose absorption of cystic fibrosis in vitro.

Enhanced Na(+)-linked nutrient absorption has been demonstrated in the cystic fibrosis bowel and may contribute to the dehydration of the luminal contents. The ability of loperamide to inhibit glucose transport was therefore assessed in jejunal biopsy specimens from children with cystic fibrosis by measuring the increased short-circuit current associated with active glucose absorption using a mini-Ussing chamber technique. The presence of loperamide in the luminal solution reduced the rise in short-circuit current induced by glucose over the range of concentrations tested (2.5 to 40 mmol.L-1). This finding suggests that the enhanced Na+ absorption, which is a feature of cystic fibrosis, is amenable to treatment and can be restored to normal levels. This result may have therapeutic implications for gastrointestinal function and may be applicable to other tissues where similar therapeutic approaches to reduce Na+ and thus water absorption are being pursued.

Adolescent↗
PubMed1994

Magnetic resonance image synthesis using a flexible model.

Image synthesis methods are based on the hypothesis that a magnetic resonance (MR) image with optimized contrast can be reproduced by synthesis from three calculated basic images of T1, T2 and spin density. This method, however, is limited by noise due to uncertainties in the initial measurements. The principal component analysis (PCA) method is based on an information theory approach that decomposes MR images into a small set of characteristic feature images. PCA images, or eigenimages, show morphology by condensing the structural information from the source images. Eigenimages have also been shown to improve contrast-to-noise ratio (CNR) compared with source images. In this study we have developed a method of synthesizing MR images using a flexible model, comprising a set of eigenimages derived from PCA. A matching process has been carried out to find the best fit between the model and a synthetic image calculated from the Bloch equations. The method has been applied to MR images obtained from a group of patients with intracranial lesions. The images derived from the flexible model show increased lesion conspicuity, reduced artefact and comparable CNR to the directly acquired images while maintaining the MR characteristic information for diagnosis.

Adult↗
PubMed1993

Rapid HLA-DQB typing by eight polymerase chain reaction amplifications with sequence-specific primers (PCR-SSP).

Molecular genotyping of HLA class II genes using group-specific DNA amplification by the PCR followed by probing with (PCR-SSO) probes is too time consuming for the typing of cadaveric organ donors. Recently, amplification of DNA using PCR-SSP has proved a reliable and rapid method for typing HLA-DRB1 genes. PCR-SSP takes 2 hours to perform and is therefore suitable for the genotyping of cadaveric donors. We have designed a set of primers that in eight PCR reactions will positively identify the HLA-DQB1 alleles corresponding to the serologically defined series HLA-DQ2, DQ4, DQ5, DQ6, DQ7, DQ8, and DQ9. Presently, 30 homozygous cell lines and 138 individuals have been typed by the DQB1 PCR-SSP technique and compared with a combination of serology and RFLP with 100% concordance. No false-negative or false-positive amplifications were recorded. All combinations of DQB1 can be readily identified. DQB1 PCR-SSP can take as little as 130 minutes from start to finish, including DNA preparation.

Alleles↗
PubMed1993

Familial hypercholesterolaemia: pilot study to identify children at risk.

AIMS: To evaluate a more effective method of identifying children with familial hypercholesterolaemia by screening a population at high risk. METHODS: Domiciliary measurement of random cholesterol concentration was made in 200 children who were first or second degree relatives of subjects with premature onset coronary artery disease. Measurements were taken by a health visitor using a portable analyser. RESULTS: Twelve new cases of familial hypercholesterolaemia were identified during the first nine months of the study. Random cholesterol concentrations were within the normal range (< 5.2 mmol/l) in 70.5% of samples tested. Forty two (21%) of patients tested had a borderline cholesterol (5.2-5.9 mmol/l) but 50% of these fell within the normal range when fasting capillary samples were analysed. Children with significant hypercholesterolaemia on random testing (concentrations of > 5.9 mmol/l) (8.5%) also had fasting venous blood assayed for high density lipoprotein (HDL) cholesterol and tri-glyceride in the laboratory. Results indicated that 6.5% of patients screened were at high risk of cardiovascular disease (ratio of total: HDL cholesterol of > 4.5), and 1% had a moderately increased risk (ratio 3.5-4.5). CONCLUSIONS: Children with familial hypercholesterolaemia can be identified from a selected "high risk" population by measuring random capillary cholesterol concentration.

Adolescent↗
PubMed1993

Clinical and socioeconomic benefits of serological HLA-DR matching for renal transplantation over three eras of immunosuppression regimens at a single unit.

The efficacy of HLA-DR matching in cadaveric renal transplantation is controversial in the cyclosporine (CsA) era. Reports have questioned both the reliability of serological HLA-DR typing as well as the benefit of matching in terms of improved graft survival. Analysis of 1,000 consecutive cadaver donor transplants performed at Oxford between 1975 and 1992 has shown that with improved immunosuppressive regimens and increased transplant success there has been a steadily diminishing influence of HLA-DR matching measured in terms of first graft outcome. For patients treated with azathioprine and prednisolone (n = 278) overall one-year first graft survival was 65%, but there was a 20% improvement associated with HLA-DR matching which has been maintained for up to 15 years. With the introduction of CsA, used either alone or in conjunction with low dose steroids (n = 96), one-year first graft survival was 69% and the difference between HLA-DR-matched and -mismatched transplants was 14%. Our current maintenance immunosuppressive protocol is triple therapy (N = 425) with an 81% one-year first graft survival for both matched and mismatched transplants. However, we do continue to find a marked correlation between HLA-DR matching and clinical course. HLA-DR-mismatched patients suffer more rejection episodes, spend a longer time in the hospital, and have higher creatinine levels at 3 months. This costs, on average, an extra 1,500 pounds for each mismatched transplant. The effect is most apparent in unsensitized males. For cadaveric regrafts, one-year graft survival for patients on triple therapy is 80% (n = 116) which does not differ from first graft survival rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Graft Rejection↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

[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↗