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Biomedical subjects

S Linton

Publications and source records attributed to S Linton.

16 recordsLinked to original sources
PubMed2001

Protein oxidation and ageing.

Organisms produce reactive oxygen species (ROS) throughout their lives. The activities of a number of key antioxidant enzymes, such as catalase, superoxide dismutase and glutathione peroxidase, which protect against the damaging effects of ROS, have been reported to decrease with increasing age, though this is not unequivocal. In contrast, sacrificial antioxidants such as ascorbate, thiols and tocopherol do not appear to decrease with increasing age. It is also possible that ROS production increases with age as a result of poorer coupling of electron transport components, and an increased level of redox-active metal ions that could catalyse oxidant formation. As a result of this decrease in antioxidant defences, and increased rate of ROS formation, it is possible that the impact of ROS increases with age. ROS are known to oxidise biological macromolecules, with proteins an important target. If the argument that the impact of ROS increases with age is true, then proteins would be expected to accumulate oxidised materials with age, and the rate of such accumulation should increase with time, reflecting impaired inefficiency of homeostasis. Here we review the evidence for the accumulation of oxidised, or modified, extra- and intra-cellular proteins in vivo.

Aging↗
PubMed2001

Judgment under emotional certainty and uncertainty: the effects of specific emotions on information processing.

The authors argued that emotions characterized by certainty appraisals promote heuristic processing, whereas emotions characterized by uncertainty appraisals result in systematic processing. The 1st experiment demonstrated that the certainty associated with an emotion affects the certainty experienced in subsequent situations. The next 3 experiments investigated effects on processing of emotions associated with certainty and uncertainty. Compared with emotions associated with uncertainty, emotions associated with certainty resulted in greater reliance on the expertise of a source of a persuasive message in Experiment 2, more stereotyping in Experiment 3, and less attention to argument quality in Experiment 4. In contrast to previous theories linking valence and processing, these findings suggest that the certainty appraisal content of emotions is also important in determining whether people engage in systematic or heuristic processing.

Adult↗
PubMed2001

A comparison of two methods for identifying surgical site infections following orthopaedic surgery.

Many infection control practitioners (ICPs) dedicate a significant amount of time and resources to surveillance of surgical site infections (SSIs). Alternative surveillance methods need to be explored to reflect the changes to the healthcare system and the increasing economic constraints placed on infection control units. This study was undertaken to compare two methods of identifying SSIs in orthopaedic surgery. Surveillance data collected routinely by ICPs was compared with data obtained from the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) coding in the medical record. Concordant results between the two methods were obtained. The use of ICD-9-CM coding, as stored in hospital patient administration system databases, has the ability to enhance routine surgical site surveillance programmes. These systems can be used as the basis for screening large data sets for SSIs and identifying where SSIs resulted in patient re-admission. A reduction in the duplication of data and time spent by the ICP on the collection of information for surveillance purposes can be achieved.

Forms and Records Control↗
PubMed2001

Animal models of inherited complement deficiency.

The initial description of murine strains deficient in complement component C5 has been followed by the recognition in a range of animal species of a variety of natural complement component deficiencies, many of which have been characterized at the molecular level. The use of such species in inflammatory and infectious experimental models has led to significant progress in understanding the role of specific complement factors (and pathways) in disease pathogenesis. Deficiencies of early complement factors are characterized by impairment of immune response, possibly due to defective processing of immune complexes. Complete (but not partial) deficiency of the central component C3 predisposes affected animals to significant risk of infection and renal disease. Studies in species deficient in the terminal pathway component C6 are particularly relevant for investigating the pathogenetic role of the terminal membrane attack complex (MAC), implicating it as a causative agent in diverse inflammatory insults such as reperfusion injury, glomerular damage, and xenograft hyperacute rejection. Further investigations in such naturally deficient strains, added to results derived from studies in knockout animals, are likely to expand our understanding of the role of the activated complement system in experimental inflammatory disease, with significant potential implications for the treatment of human disease.

Animals↗
PubMed2000

Inherited complement deficiencies in animals.

Following the initial description of natural C5 deficiency in inbred mice, a growing number of complement component deficiencies in animals have been described, caused by a variety of genetic defects. Studies on such animals have contributed greatly to an understanding of the specific roles of classical, alternative and terminal pathway activation and inhibition in many infectious and inflammatory diseases. Further investigations in the more recently described models, in combination with the use of genetically engineered knockout mice (with targeted disruption of individual complement components and inhibitors), should continue to provide a fertile source of information regarding the role of complement in such experimental situations. This information is likely to have significant therapeutic implications for human disease.

Animals↗
PubMed1998

A national center for biocomputation: in search of a patient-specific interactive virtual surgery workbench.

This report describes the three-dimensional imaging and virtual environment technologies developed in NASA's Biocomputation Center for scientific purposes that have now led to applications in the field of medicine. A major goal is to develop a virtual environment surgery workbench for planning complex craniofacial and breast reconstructive surgery, and for training surgeons.

Breast Neoplasms↗
PubMed1997

Clinical diagnosis of ocular sarcoidosis.

PURPOSE: To assess the value of raised serum angiotensin converting enzyme (ACE) levels in making a clinical diagnosis of ocular sarcoidosis in patients with intraocular inflammation, compatible with sarcoidosis, in whom tissue biopsy is either not practical or not possible. METHODS: The ocular manifestations and clinical course of 22 patients with intraocular inflammation compatible with sarcoidosis and elevated ACE level (including 11 patients with abnormal chest radiograph) were compared with those of a group of 18 patients with intraocular inflammation due to biopsy-proven sarcoidosis. The mean follow-up (+/- SD) was 4.5 +/- 3.4 years in the presumed ocular sarcoidosis group and 7.8 +/- 5.3 years in the biopsy-proven sarcoidosis group. RESULTS: There was no difference in sex, race and age distribution between the two groups. No statistically significant difference could be found between the ocular manifestations seen in each group. The most common finding was retinal vasculitis with panuveitis, seen in 86.4% of the presumed ocular sarcoidosis group and in 83.3% of the biopsy-proven sarcoidosis group. CONCLUSIONS: These results suggest that intraocular inflammation compatible with sarcoidosis in conjunction with raised ACE levels would be accordant with a diagnosis of sarcoidosis in patients in whom histological diagnosis is either not practical or not possible.

Adolescent↗
PubMed1997

Urate deposits in the gecarcinid land crab Gecarcoidea natalis are synthesised de novo from excess dietary nitrogen

The urate content of the gecarcinid land crab Gecarcoidea natalis was correlated to the amount of nitrogen assimilated. Crabs fed a high-nitrogen diet (ad libitum amounts of soy beans and fig leaves, Ficus macrophylla) for 6 weeks assimilated approximately 23 times more nitrogen (33.9±5.6mmolkg-1day-1) than animals fed a diet low in nitrogen (fig leaves alone) (1.5±0.7mmolkg-1day-1). Animals maintained on a high-nitrogen diet accumulated urate (67.1±29.4mmolkg-1drymass), while animals fed the low-nitrogen diet did not accumulate significant amounts of urate compared with the control animals killed at the beginning of the dietary period. The urate deposits clearly originate from the excess dietary nitrogen ingested on the high-nitrogen diet. The intake of preformed dietary purine was low (0.028±0.005mmolkg-1drymass) and at most could only account for 0.04% of the urate accumulated by crabs fed the high-nitrogen diet. This indicates that the urate was synthesised de novo. When crabs were fed a high-nitrogen diet supplemented with [15N]glycine, the 15N heavy isotope was incorporated into urate. This provided direct evidence that the urate was synthesised de novo.

Journal Article↗
PubMed1993

The GALS locomotor screen and disability.

OBJECTIVES: Examination of the locomotor system is frequently neglected. Therefore, the GALS locomotor screen (Gait, Arms, Legs, Spine) has been proposed by Doherty et al as a practical method of identifying functionally important problems. This study was designed to test whether this screen reflects functional impairment, as measured by accepted health status measures. METHODS: Two observers performed the GALS screen in a total of 83 patients with a variety of musculoskeletal conditions. The examination components of GALS were rated by a simple 0 to 3 scale. Physical ability was further assessed by Health Activity Questionnaire (HAQ), Barthel index and Steinbrocker's ARA classification. RESULTS: For the total patient group, Spearman correlations between GALS and the three functional indices were good (r = 0.62 to 0.71, p < 0.001). Correlations were equally good for rheumatoid arthritis patients alone (r = 0.65 to 0.70, p < 0.001), but less good although still significant for the other miscellaneous rheumatic conditions (r = 0.31 to 0.46, p < 0.05). Observed proportional agreement between the two observers for the individual scores was > 70%, with a kappa statistic k = 0.49 to 0.74. CONCLUSIONS: The GALS screen is a reliable and valid measure of functional ability, compared with standard accepted indices in a variety of musculoskeletal diseases. This supports the proposal for its use as a screening test by general practitioners and medical students.

Adolescent↗
PubMed1986

Effects of graded levels of dietary phosphorus on bone mineralization in the very young poult.

An experiment was conducted to determine the effects of graded levels of dicalcium phosphate on bone mineralization in 1 and 3-week-old poults. Corn-soybean meal diets calculated to contain 1.5% calcium and either .35, .55, .75, .95, or 1.15% available phosphorus were fed to battery brooder reared poults for 3 weeks. Body weights and percent tibia ash were determined at 1 and 3 weeks. Body weight was not significantly affected by dietary phosphorus at either 1 or 3 weeks of age. Percent tibia ash was significantly greater in 1-week-old poults receiving a minimum of .75% available phosphorus. In 3-week-old poults, maximum tibia ash was obtained with with a minimum of .55 available phosphorus. This study suggests the level of dietary phosphorus necessary to achieve maximum tibia ash in 3-week-old poults is not sufficient for maximum tibia ash in 1-week-old poults.

Aging↗
PubMed1979

A child is born.

Explore the source record for details and available documents.

Child↗