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Biomedical subjects

R Taylor

Publications and source records attributed to R Taylor.

At least 199 records · Page 11Linked to original sources
PubMed1999

Lipids increase after solitary pancreas transplantation.

OBJECTIVE: The aims of this study were to determine 1) changes in lipids after solitary pancreas transplantation (SPTX) in patients with type 1 diabetes and 2) factors that influence those changes. RESEARCH DESIGN AND METHODS: Lipids were evaluated prospectively in 24 patients who underwent SPTX. Three were excluded because of early graft failure. The remaining patients (n = 21; 13 men, 8 women) were studied for changes in lipids over time (pre-SPTX, 0-2, 3-6, 7-12, and > 12 months). Glycohemoglobin, serum creatinine, BMI, and medications were also analyzed for their effects on lipid changes. RESULTS: Cholesterol, HDL, and LDL decreased in the immediate postoperative period (0-2 months), whereas triglycerides (TGs) increased (P < 0.05). At 3-6 months, cholesterol, HDL, and TG were higher than before the SPTX, whereas LDL returned to pre-SPTX levels. After 12 months, HDL and TG remained higher than their pre-SPTX levels (P < 0.05). During the study, systolic and diastolic blood pressure increased, renal function decreased, glyco-hemoglobin improved, and weight was unchanged. Changes in cholesterol/HDL ratio, HDL, and TG correlated with changes in prednisone dose (P < 0.05), and changes in TG correlated with changes in creatinine (P < 0.05). The same pattern of lipids occurred in patients prescribed or not prescribed hypolipidemic agents. CONCLUSIONS: Lipids do not improve within the 1st year after SPTX, despite improved glycemic control and blood pressure control, and renal function is worse. These results are in contrast to those reported for combined kidney-pancreas transplantation, where lipids, blood pressure, and renal function improved immediately after transplant. Further studies are needed to determine whether lipids continue to change with time after SPTX. The impact of these changes after SPTX on overall cardiovascular risk is unknown.

Blood Pressure↗
PubMed1999

Personality and performance on a frustrating cognitive task.

Eysenck's biological model of personality suggests that extravertive persons will not persevere when solving boring, frustrating problems. This hypothesis was tested using a difficult jigsaw task. Quitting behaviour was strongly associated with scores on Extraversion.

Cognition↗
PubMed1999

Mood disorders in patients after treatment for primary intracranial tumours.

The frequency of mood disorder was studied in a cohort of patients with treated intracranial glioma or meningioma, where psychological morbidity was related to physical and neuropsychological functioning and to the patients' knowledge of their disease. Forty patients were assessed on a range of physical, psychological and neuropsychological measures, with additional interview of a relative to obtain supplementary information regarding each patients' knowledge of their disease. Two (5%) of the 40 patients had clinically significant levels of anxiety, six (15%) clinically significant levels of depression and 92% full or intermediate knowledge about their prognosis. Psychological morbidity was associated with high levels of physical disability and also with cognitive dysfunction, but was not related to the grade of the patient's tumour or the extent to which the patient was aware of the nature of his or her disease. A proportion of patients with intracranial tumours suffer levels of psychological distress sufficient to warrant psychological and/or pharmacological intervention.

Adolescent↗
PubMed1999

The role of heat shock proteins in mammalian differentiation and development.

Heat shock proteins (HSPs) have been identified in all cells, prokaryotic and eukaryotic, to protect the cells from harmful insults and stress. Increased HSP synthesis can also result during normal cellular functions and also respond to exposure from environmental stress and infection. Although the molecular mechanisms responsible for HSP cellular protection are still not fully understood, their expression is critical for cellular survival and can be modified by cell signal transducers such as intracellular pH, cyclic AMP, Ca2+ Na+, inositol [correction of inostitol] triphosphate, protein kinase C, and protein phosphates. Most HSPs interact, assemble, fold, unfold, bind, transport, translocate and 'chaperone' other proteins in the cell and alter their function.

Animals↗
PubMed1998

Purification and characterization of monomeric Escherichia coli vitamin B12 receptor with high affinity for colicin E3.

The btuB gene product from Escherichia coli is a 66.5-kDa integral outer membrane protein required for high-affinity uptake of cyanocobalamin and the translocation of E group colicins and colicin A. Efficient purification of overexpressed BtuB containing stoichiometric levels of bound lipopolysaccharide has been achieved through the extraction of the outer membrane with nonionic detergent followed by ion-exchange chromatography. Analysis of far UV circular dichroism spectra indicates a predominantly beta-sheet secondary structure (76 +/- 4%) with a low alpha-helical content (15 +/- 3%), providing the first direct evidence for secondary structure models derived from sequence and hydropathy analysis. Characterization of the octylglucoside-solubilized receptor by sedimentation equilibrium and sedimentation velocity analysis reveals a monodisperse protein-detergent complex of approximately 89 kDa with a sedimentation coefficient of 4.7 S which, after correction for bound detergent, indicates that BtuB is purified as a monomer. BtuB binds vitamin B12 with a stoichiometry of approximately 1:1, as observed by a shift in the sedimentation profile of the vitamin to the much faster velocity observed for the protein-detergent complex. The preincubation of colicin E3 with stoichiometric levels of BtuB protects susceptible strains from the lethal effects of the colicin and results in a complex with a sedimentation coefficient appropriate for a BtuB-detergent-colicin E3 complex, demonstrating that monomeric BtuB retains high affinity for this particular ligand after isolation.

Bacterial Outer Membrane Proteins↗
PubMed1998

Directional preferences of intermolecular contacts to hydrophobic groups.

Analysis of data from the IsoStar library shows that many hydrophobic groups exhibit strikingly strong directional preferences in their intermolecular interactions. Specific directional interactions may occur because of the large quadrupole moments of many aromatic ring systems, the residual electropositive charge on most carbon-bound H atoms and the effects of polarization on soft hetero-ring atoms such as sulfur. In consequence, the binding of a hydrophobic group to a hydrophobic protein cavity is not simply a matter of matching complementary shapes. Directional preferences of nonbonded contacts to hydrophobic groups may need to be taken into account in parameterizing the next generation of protein-ligand docking programs.

Databases, Factual↗
PubMed1998

Rapid method for the simultaneous measurement of nicotine and cotinine in urine and serum by gas chromatography-mass spectrometry.

A simple, sensitive, and rapid gas chromatographic-mass spectrometric method is described for the simultaneous detection and quantitation of nicotine and its metabolite, cotinine, in urine and serum. The analytes and their respective deuterated internal standards were extracted by liquid-liquid extraction coupled to centrifugation and evaporation. The detection limit of the assay was 0.16 ng/ml for both nicotine and cotinine. The limit of quantitation for each analyte was 1.25 ng/ml.

Cotinine↗
PubMed1998

Effects of resective surgery for left-sided intracranial tumours on language function: a prospective study.

BACKGROUND: Although language disorders occur in about 50% of patients with a left hemispheric tumour and are a significant cause of morbidity, the effects of resective neurosurgery and their relation to tumour pathology are unclear. We report the immediate effects of resective surgery on language functions in a heterogeneous group of patients with left-sided intracranial tumours. METHODS: 40 patients were studied. The Western Aphasia Battery (WAB) and Boston Naming Test (BNT) were administered preoperatively and before discharge following resective neurosurgery. Dexamethasone dose at time of testing was recorded, as was time taken to complete the tests, and tumour neuropathology. FINDINGS: 15 patients with normal aphasia quotients and language quotients before resective surgery all had normal quotients postoperatively. 25 who were dysphasic (ie, aphasia quotient <93.8) preoperatively showed significant postoperative improvements in both their mean aphasia quotient (from 81.8 to 89.1, p=0.004) and their mean language quotient (from 73.4 to 85.4, p=0.001), though 13 remained dysphasic. Two of the 25 dysphasic patients had their WAB scores lowered by tumour resection. The findings and postoperative changes in BNT scores were almost identical to the pattern of those in WAB scores. At second assessment, dexamethasone therapy was significantly (p<0.01) lower than preoperative dose (reduction from mean 10.3 mg/day to 0.7 mg/day in the dysphasic group). Patients with glioblastoma were more likely to have lower aphasia quotients, language quotients, and BNT scores than patients with anaplastic glioma, metastasis, or meningioma. Although the glioblastoma group had the greatest improvements in WAB operative scores, 57% remained dysphasic after resective surgery. Two additional patients declined postoperative assessment. INTERPRETATION: Resective surgery for left-sided intracranial tumours significantly improves language function in dysphasic patients, and is unlikely to impair language functions in non-dysphasic patients. Dysphasia and its response to resective surgery are related to the tumour neuropathology.

Aphasia↗
PubMed1998

Secretory component of immunoglobulin A in maternal serum and the prediction of preterm delivery.

OBJECTIVE: Our purpose was to determine whether the secretory component of immunoglobulin A in maternal serum predicts delivery before 34 weeks' gestation. STUDY DESIGN: Primigravid women of an urban population in New Zealand were recruited at booking into a prospective longitudinal nested case control study (n = 1651; after exclusions and withdrawals, n = 1511). Serum was collected at 8 to 12 weeks, 15 to 18 weeks, 21 to 24 weeks, 28 to 30 weeks, and 36 to 38 weeks of gestation and 6 weeks post partum. Concentrations of the secretory component of immunoglobulin A were determined by enzyme-linked immunosorbent assay in all women who were delivered preterm (n = 53) and in controls randomly selected from women delivered at > or =37 weeks' gestation (n = 178). RESULTS: Serum concentrations of the secretory component of immunoglobulin A were similar in women delivered at term or preterm throughout pregnancy (n = 21 delivered at <34 weeks and n = 32 at 34 to 36.9 weeks, incidence 3.5%). Receiver-operator characteristic curves showed no discriminating ability of the secretory component of immunoglobulin A. Smokers had 50% higher concentrations than nonsmokers did (p < 0.0001 by analysis of variance). CONCLUSION: The secretory component of immunoglobulin A in maternal serum does not predict preterm delivery in a low-risk population.

Adolescent↗
PubMed1998

Rater reliability of Fahn's tremor rating scale in patients with multiple sclerosis.

OBJECTIVE: Assessment of movement disorders in patients with multiple sclerosis (MS) is difficult because of the complex nature of the movement disorders. The aim of this study was to determine the reliability of Fahn's Tremor Rating Scale (FTRS) in assessing movement disorders in patients with MS. METHOD: Videos were made of 10 patients with MS showing their rest, postural, action/intention, and goal-related movement disorders as well as their performance of spirometry, a volumetric task, and timed functional tasks. Ratings of tremor were carried out by one rater on two occasions 3 months apart and by 8 raters on one occasion using FTRS. RESULTS: Intrarater reliability was generally very good, with no significant "drift" in ratings over time. Interrater reliability was generally good, with some variation in interpretation of scoring criteria that may reflect raters' backgrounds. CONCLUSION: The FTRS is a reliable and potentially useful tool with which to assess movement disorders in patients with MS.

Activities of Daily Living↗
PubMed1998

Retention of oral microorganisms on cobalt-chromium alloy and dental acrylic resin with different surface finishes.

STATEMENT OF PROBLEM: The effect of surface finish of dental materials on the subsequent contamination by microorganisms. PURPOSE: This study compared the retention of Streptococcus oralis, Actinomyces viscosus, and Candida albicans on polished, sandblasted (fine and coarse) and electrobrightened cobalt-chromium alloy and dental acrylic resin to assess in vitro the effect of such techniques on prosthesis contamination. MATERIAL AND METHODS: Standardized cell suspensions were incubated with test materials for 1 hour at 37 degrees C, after which retained cells were counted by using image analysis (percentage area of a microscopic field covered by cells). RESULTS: Retention of bacterial cells was substantial (S oralis 12% to 20% and A viscosus 9% to 16%) irrespective of surface finish. Maximal retention was observed on cobalt-chromium alloy that had undergone fine sandblasting and electrobrightening (P < .01). For C albicans, an increase in surface roughness (0.15 to 3.53 microns) resulted in an increase in retention (3% to 9%). CONCLUSION: Cell size and the type of roughening significantly affected the retention of microorganisms on surfaces. Electrobrightening of cobalt-chromium alloy did not reduce the surface roughness or subsequent cell attachment.

Acrylic Resins↗