PubMed Health⌕ Search

Biomedical subjects

R Stephens

Publications and source records attributed to R Stephens.

At least 37 records · Page 2Linked to original sources
PubMed2003

Radiation hybrid mapping of 304 novel microsatellites in the domestic cat genome.

Effective utilization of the domestic cat as an animal model for hereditary and infectious disease requires the development and implementation of high quality gene maps incorporating microsatellites and conserved coding gene markers. Previous feline linkage and radiation hybrid maps have lacked sufficient microsatellite coverage on all chromosomes to make effective use of full genome scans. Here we report the isolation and genomic mapping of 304 novel polymorphic repeat loci in the feline genome. The new loci were mapped in the domestic cat radiation hybrid panel using an automated fluorescent TAQ-Man based assay. The addition of these 304 microsatellites brings the total number of microsatellites mapped in the feline genome to 580, and the total number of loci placed onto the RH map to 1,126. Microsatellites now span every autosome with an average spacing of roughly one polymorphic STR every five centimorgans, and full genome coverage of one marker every 2.7 megabases. These loci now provide a useful tool for undertaking full-genome scans to identify genes associated with phenotypes of interest, such as those relating to hereditary disease, coat color, patterning and morphology. These resources can also be extended to the remaining 36 species of the cat family for population genetic and evolutionary genomic analyses.

Animals↗
PubMed2001

Sequence, chromosomal location and expression analysis of the murine homologue of human RAD51L2/RAD51C.

The Rad51 protein has been shown to play a vital role in the DNA repair process. In humans, its interaction with proteins like BRCA1 and BRCA2 has provided an insight into the mechanism of how these molecules function as tumor suppressors. Several members of the Rad51-like family have been recently identified, including RAD51L2. This gene has been found to be amplified in breast tumors suggesting its role in tumor progression. Here, we describe the cloning of the murine homologue of the human RAD51L2/RAD51C gene. Sequence analysis has revealed that the murine Rad51l2 protein is 86% identical and 93% similar to its human homologue. In spite of such high sequence conservation, the murine protein lacks the first nine amino acids present in the human protein. We have cloned and confirmed the sequence of the 5' end of the murine Rad51l2 cDNA using 5' RACE technique as well as by sequencing the genomic region flanking the first exon of the murine Rad51l2 gene. Northern analysis shows that Rad51l2 is expressed in several adult tissues as well as in embryos at various developmental stages. The murine Rad51l2 gene maps to chromosome 11 and is located in the syntenic region of human chromosome 17q22-23, where the human RAD51L2 is present.

Animals↗
PubMed2001

Feasibility of the use of eye movement data in the analysis of neurobehavioral test performance.

Better understanding of the functions and abilities underlying some neurobehavioral tests would assist the assessment of the consequences to the health or well-being of exposed populations for which decrements in such tests have been found. Eye movements, which can be useful in evaluating specific theories of visual and cognitive processes, were measured while a single participant completed the NES Symbol-Digit Substitution test. Relationships between the durations and the frequencies of eye fixations within different parts of the test material and overall test performance were examined. The overall pattern of eye-movement behavior observed was as predicted: fixations within three regions of visual interest were made, usually in the order lower matrix, upper matrix, keyboard. Both the upper matrix fixation latency and the number of regional fixations made per item were found to be strongly associated with overall item response latency. This suggests that speed and efficiency of searching and the ability to maintain concentration appeared to be key attributes related to test performance for this participant. For suitable tests, eye-movement data may be useful for assessing and measuring the latencies of subtask components in a real test situation. Monitoring eye movement represents an alternative methodology to using sub test composites, or factor analysis, as a means of tapping into the functions underlying neurobehavioral test performance.

Eye Movements↗
PubMed2001

A randomized controlled trial of brief cognitive-behavioral interventions for cannabis use disorder.

The increasing demand for treatment for cannabis dependence in Australia and internationally has led to the identification of significant gaps in knowledge of effective interventions. A randomized controlled trial of brief cognitive-behavioral interventions (CBT) for cannabis dependence was undertaken to address this issue. A total of 229 participants were assessed and randomly assigned to either a six-session CBT program (6CBT), a single-session CBT intervention (1CBT), or a delayed-treatment control (DTC) group. Participants were assisted in acquiring skills to promote cannabis cessation and maintenance of abstinence. Participants were followed-up a median of 237 days after last attendance. Participants in the treatment groups reported better treatment outcomes than the DTC group. They were more likely to report abstinence, were significantly less concerned about their control over cannabis use, and reported significantly fewer cannabis-related problems than those in the DTC group. Those in the 6CBT group also reported more significantly reduced levels of cannabis consumption than the DTC group. While the therapist variable had no effect on any outcome, a secondary analysis of the 6CBT and 1CBT groups showed that treatment compliance was significantly associated with decreased dependence and cannabis-related problems. This study supports the attractiveness and effectiveness of individual CBT interventions for cannabis use disorders and the need for multisite replication trials.

Adult↗
PubMed2001

Two episodes of life-threatening anaphylaxis in the same patient to a chlorhexidine-sulphadiazine-coated central venous catheter.

Chlorhexidine allergy has been described in the literature, mainly in Japanese individuals. Most reactions have been limited to the skin, mild in severity and a result of chlorhexidine containing solutions such as 'Savlon' (Novartis Consumer Health, Horesham, UK). We describe what we believe is the first reported case of anaphylaxis in a European patient to a chlorhexidine- sulphadiazine-coated central venous catheter.

Anaphylaxis↗
PubMed2001

The effects of balanced versus saline-based hetastarch and crystalloid solutions on acid-base and electrolyte status and gastric mucosal perfusion in elderly surgical patients.

UNLABELLED: The IV administration of sodium chloride solutions may produce a metabolic acidosis and gastrointestinal dysfunction. We designed this trial to determine whether, in elderly surgical patients, crystalloid and colloid solutions with a more physiologically balanced electrolyte formulation, such as Hartmann's solution and Hextend, can provide a superior metabolic environment and improved indices of organ perfusion when compared with saline-based fluids. Forty-seven elderly patients undergoing major surgery were randomly allocated to one of two study groups. Patients in the Balanced Fluid group received an intraoperative fluid regimen that consisted of Hartmann's solution and 6% hetastarch in balanced electrolyte and glucose injection (Hextend). Patients in the Saline group were given 0.9% sodium chloride solution and 6% hetastarch in 0.9% sodium chloride solution (Hespan). Biochemical indices and acid-base balance were determined. Gastric tonometry was used as a reflection of splanchnic perfusion. Postoperative chloride levels demonstrated a larger increase in the Saline group than the Balanced Fluid group (9.8 vs 3.3 mmol/L, P = 0.0001). Postoperative standard base excess showed a larger decline in the Saline group than the Balanced Fluid group (-5.5 vs -0.9 mmol/L, P = 0.0001). Two-thirds of patients in the Saline group, but none in the Balanced Fluid group, developed postoperative hyperchloremic metabolic acidosis (P = 0.0001). Gastric tonometry indicated a larger increase in the CO2 gap during surgery in the Saline group compared with the Balanced Fluid group (1.7 vs 0.9 kPa, P = 0.0394). In this study, the use of balanced crystalloid and colloid solutions in elderly surgical patients prevented the development of hyperchloremic metabolic acidosis and resulted in improved gastric mucosal perfusion when compared with saline-based solutions. IMPLICATIONS: This prospective, randomized, blinded trial showed that, in elderly surgical patients, the use of balanced IV solutions can prevent the development of hyperchloremic metabolic acidosis and provide better gastric mucosal perfusion compared with saline-based fluids.

Acid-Base Equilibrium↗
PubMed2001

Issues and trends in care of the hypertensive client.

This article discusses issues and trends in care of the hypertensive client that pertain to practice, education, research, and health policy. Clinical practice issues center around obtaining accurate blood pressure measurements and educating patients about health promotion interventions and use of medications. These topics are important in the education of the beginning nurse student as well. Researchers have studied risk factors, incidence, and prevalence in global populations; use of pharmacologic agents; and investigative methods employing technology. Researchers are beginning to explore more holistic approaches to controlling risk factors before hypertension occurs. Funding for public education regarding prevention and control of hypertension is a number one health policy issue.

Blood Pressure↗
PubMed2001

Severe juvenile chronic constipation.

Constipation in the paediatric population is common and encompasses a spectrum of organic and functional pathology which differ from that of the adult population. Recently an expert group published a comprehensive system of classification of childhood functional gastrointestinal disorders that may have useful clinical application. We present the case of an adolescent schoolgirl with severe constipation with extreme anorectal, urological and neurological sequelae who displayed inappropriate behavioral response to her condition. The patient appeared inappropriately unmotivated and undisturbed by the severity of her constipation. This abnormal psychological habituation and adaptation to an abnormal bowel habit perpetuated the constipation. In addition, we examined the role of recent advances in anorectal investigation techniques and treatment in the context of the recent guidelines issued by the American Gastroenterological Association

Adolescent↗
PubMed2000

Effect of intrauterine treatment with prostaglandin E2 prior to insemination of mares in the uterine horn or body.

Two trials were conducted to investigate the effects of intrauterine infusion of PGE2 and uterine horn insemination on pregnancy rates in mares achieved by breeding with a suboptimal number of normal spermatozoa. Estrus was synchronized and mares were teased daily with a stallion to detect estrus. Mares in estrus were examined by transrectal palpation and ultrasonography to monitor follicular status. On the first day a 35-mm diameter follicle was present, hCG (1500 IU, iv) was administered and the mares were bred the next day. Mares (Trial 1, n = 34; Trial 2, n = 28) were inseminated with 25 million total spermatozoa from either a stallion with good semen quality (Trial 1) or poor semen quality (Trial 2). In each trial, mares were assigned to 1 of 4 treatment groups as follows: Group PGE-HI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; Group PGE-BI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body; Group SAL-HI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; or Group SAL-BI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body. After breeding, mares were examined daily by transrectal ultrasonography to confirm ovulation, and were re-examined 14 to 16 d after ovulation for pregnancy status. Data were analyzed by Chi-square. Overall pregnancy rates were 59% for stallion 1 and 29% for stallion 2. Group pregnancy rates did not differ for mares bred by either stallion (P > 0.10). Pregnancy rates were not altered by horn insemination for either stallion (P > 0.10). Intrauterine infusion of PGE2 improved pregnancy rate in mares bred by the stallion with good quality semen (P < 0.05), but did not alter pregnancy rate in mares bred by the stallion with poor quality semen (P > 0.10). Further research is warranted to determine if intrauterine infusion of PGE2 will enhance spermatozoal colonization of the oviduct and pregnancy rates in mares, and if PGE-treatment will improve pregnancy rates achieved by subfertile stallions.

Animals↗
PubMed2000

Practice and policy of measuring quality of life and health economics in cancer clinical trials: a survey among co-operative trial groups.

BACKGROUND: Co-operative groups have played an important role in the advance of health-related quality of life (HRQL) research. However, definitions of the concept, criteria for selection of existing instruments and methods for data collection and interpretation remain poorly defined in the literature. A survey was conducted amongst the major cancer co-operative groups in order to gain a better understanding of their current policy and processes to ensure optimal HRQL data collection within cancer clinical trials. The topic of health economics was similarly addressed. METHODS: A written questionnaire was addressed to 16 major European and North American cancer co-operative groups. Eleven groups responded (response rate: 69%). however, one group could not provide information for the survey, thus ten questionnaires were available for analysis. RESULTS: The results from this survey among co-operative groups show that HRQL (more than health economics) is recognized as an important, although usually secondary, outcome measure in oncology trials. On the whole, co-operative groups have a rather flexible policy towards the inclusion of HRQL (and HE) into their clinical trials, and practice is very much on a case-by-case basis, but use standard practice guidelines and internal procedures is to ensure well-defined study protocols and enhance good quality studies.

Attitude↗
PubMed2000

Recovery from surgery: grappling with an elusive concept.

When we ask our patients 'How are you?', can we quantify the answer? There is no ideal measure for every circumstance. This article will discuss the issues in measuring postsurgical recovery, describe different approaches, and consider future research.

Humans↗