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Biomedical subjects

B Riley

Publications and source records attributed to B Riley.

At least 19 recordsLinked to original sources
PubMed2004

Multicenter linkage study of schizophrenia loci on chromosome 22q.

The hypothesis of the existence of one or more schizophrenia susceptibility loci on chromosome 22q is supported by reports of genetic linkage and association, meta-analyses of linkage, and the observation of elevated risk for psychosis in people with velocardiofacial syndrome, caused by 22q11 microdeletions. We tested this hypothesis by evaluating 10 microsatellite markers spanning 22q in a multicenter sample of 779 pedigrees. We also incorporated age at onset and sex into the analysis as covariates. No significant evidence for linkage to schizophrenia or for linkage associated with earlier age at onset, gender, or heterogeneity across sites was observed. We interpret these findings to mean that the population-wide effects of putative 22q schizophrenia susceptibility loci are too weak to detect with linkage analysis even in large samples.

Chromosome Mapping↗
PubMed2003

Carrier risk status changes resulting from mutation testing in hereditary non-polyposis colorectal cancer and hereditary breast-ovarian cancer.

CONTEXT: In hereditary cancer syndrome families with an identified cancer associated mutation, mutation testing changes the carrier risk status of the tested person and may change the carrier risk status of relatives. OBJECTIVE: This study aimed to describe the change in the distribution of carrier risk status resulting from testing in hereditary breast-ovarian cancer (HBOC) and hereditary non-polyposis colorectal cancer (HNPCC) families. DESIGN: This was an observational cohort study. PATIENTS: The cohort included members of 75 HBOC and 47 HNPCC families. Of the 10 910 cohort members, 1408 were tested for a mutation and learned their test results. OUTCOME MEASURE: Carrier risk for all cohort members was assessed before and after mutation testing. RESULTS: There was a change in carrier risk status in 2906 subjects after testing of 1408 family members. The most common type of carrier risk change, from at risk to non-carrier status, accounted for 77% of the risk changes; 12% were a change to known carrier status from a lower risk. Sixty percent of persons with a carrier risk status change were not themselves tested; their risk status changed because of a relative's test result. CONCLUSIONS: Carrier risk status changes from uncertainty to certainty (that is, to carrier or to non-carrier) account for 89% of risk changes resulting from testing. These risk changes affect cancer prevention recommendations, most commonly reducing their burden. Current practices do not ensure that untested family members are informed about changes in their carrier risk status which result from mutation testing of their relatives.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Electrogastrographic norms in children: toward the development of standard methods, reproducible results, and reliable normative data.

BACKGROUND: Surface electrogastrography (EGG) is a noninvasive technique that detects gastric myoelectrical electric activity, principally the underlying pacemaker activity generated by the specialized interstitial cells of Cajal. Interest in the use of this methodology has grown because of its potential applications in describing functional gastrointestinal disorders, particularly as a tool in the evaluation of nausea, anorexia, and other dyspeptic symptoms. METHODS: Fifty-five healthy volunteers (27 female), ranging in age from 6 to 18 years (mean, 11.7 years), were studied for a 1-hour baseline preprandial period and a 1-hour postprandial period after consumption of a standard 448-kcal meal. Recordings were obtained with an EGG Digitrapper or modified Polygraph (Medtronic-Synectics, Shoreview, MN). Spectral analysis by an autoregressive moving average method was used to extract numerical data on the power and frequency of gastric electrical activity from the EGG signal. RESULTS: The authors present normative data for healthy children and adolescents studied under a standardized protocol. Mean dominant frequency was found to be 2.9 +/- 0.40 cycles per minute preprandially and 3.1 +/- 0.35 postprandially, with 80% +/- 13% of test time spent in the normogastric range (2-4 cycles per minute) before and 85% +/- 11% after the test meal. The response of several key parameters to meal consumption was considered, and the effects of age, gender, and body mass index (BMI) on the EGG were sought. CONCLUSIONS: There is a postprandial increase in the rhythmicity and amplitude of gastric slow waves, as other investigators have shown in adults. Key normative values are not dependent on age, gender, or BMI. The authors discuss limitations in the data set and its interpretability. The authors establish a normative data set after developing a standardized recording protocol and test meal and show that EGG recordings can be obtained reliably in the pediatric population. Development of similar norms by investigators using the EGG is crucial for future exploration of the validity and clinical application of the EGG. Differences in test conditions of signal detection and analytic methods influence EGG results substantially, and caution should be used when comparing results across centers.

Adolescent↗
PubMed2001

Dissemination of heart health promotion: lessons from the Canadian Heart Health Initiative Ontario Project.

Situated in central-eastern Canada, Ontario is the largest province with a population of 11 million. Ontario is considered a fairly rich province at the centre of Canada's manufacturing and financial sectors. Public health services in Ontario are primarily delivered through public health departments, each administered by a local board of health and regulated by provincial legislation and program guidelines. The Canadian Heart Health Initiative Ontario Project (CHHIOP) was a four year project (1994 to 1998) undertaken as part of the dissemination phase of the Canadian Heart Health Initiative (CHHI) (see O'Loughlin et al., p.4). CHHIOP is one component of a long-term process to develop and implement effective heart health programs in Ontario.

Canada↗
PubMed2001

Quality of life for women with physical disabilities.

This article emphasizes the role of several factors on the QOL of women with disabilities. Future studies might examine ways to merge these factors to examine their long-term consequences in the lives of women with disabilities and, hence, society at large. Findings should provide a basis for policymaking and clinical rehabilitation interventions designed to promote greater QOL for women with disabilities-a QOL that offers vigorous prosperity, flourishing health, and full social participation.

Adaptation, Physiological↗
PubMed2000

Identification and characterization of an ataxin-1-interacting protein: A1Up, a ubiquitin-like nuclear protein.

Expansion of a polyglutamine tract within ataxin-1 causes spinocerebellar ataxia type 1 (SCA1). In this study, we used the yeast two-hybrid system to identify an ataxin-1-interacting protein, A1Up. A1Up localized to the nucleus and cytoplasm of transfected COS-1 cells. In the nucleus, A1Up co-localized with mutant ataxin-1, further demonstrating that A1Up interacts with ataxin-1. Expression analyses demonstrated that A1U mRNA is widely expressed as an approximately 4.0 kb transcript and is present in Purkinje cells, the primary site of SCA1 cerebellar pathology. Sequence comparisons revealed that A1Up contains an N-terminal ubiquitin-like (UbL) region, placing it within a large family of similar proteins. In addition, A1Up has substantial homology to human Chap1/Dsk2, a protein that binds the ATPase domain of the HSP70-like Stch protein. These results suggest that A1Up may link ataxin-1 with the chaperone and ubiquitin-proteasome pathways. In addition, these data support the concept that ataxin-1 may function in the formation and regulation of multimeric protein complexes within the nucleus.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Halo vest effect on balance.

OBJECTIVE: To determine the effect of a halo vest, a cervical orthosis, on clinically relevant balance parameters. DESIGN: Subjects performed unipedal stance (with eyes open and closed, on both firm and soft surfaces) and functional reach, with and without the application of a halo vest. SUBJECTS: A convenience sample of 12 healthy young subjects, with an equal number of men and women. OUTCOME MEASURES: Seconds for unipedal stance (maximum 45); inches for functional reach. RESULTS: Both unipedal stance times and functional reach (mean +/- standard deviation) were significantly decreased with the halo vest as compared to without it (29.1+/-5.8 vs. 32.8+/-6.4 seconds, p = .002; 12.9+/-1.4 vs. 15.1+/-2.1 inches, p<.01). CONCLUSION: A halo vest causes an acute impairment in balance in the healthy young. It is likely that the impairment would be greater in older or injured patients, thus increasing their risk for a fall, which could have devastating consequences.

Adult↗
PubMed2000

Effects of a short-term health promotion intervention for a predominantly African-American group of stroke survivors.

BACKGROUND: The study examined the effects of a 12-week health promotion intervention for a predominantly urban African-American population of stroke survivors. DESIGN: A pre-test/post-test lag control group design was employed. PARTICIPANTS/SETTING: Participants were 35 stroke survivors (9 male, 26 female) recruited from local area hospitals and clinics. MAIN OUTCOME MEASURES: Biomedical, fitness, nutritional, and psychosocial measures were employed to assess program outcomes. RESULTS: Treatment group made significant gains over lag controls in the following areas: (1) reduced total cholesterol, (2) reduced weight, (3) increased cardiovascular fitness, (4) increased strength, (5) increased flexibility, (6) increased life satisfaction and ability to manage self-care needs, and (7) decreased social isolation. CONCLUSION: A short-term health promotion intervention for predominantly African-American stroke survivors was effective in improving several physiological and psychological health outcomes.

Black or African American↗
PubMed2000

Exercise training in a predominantly African-American group of stroke survivors.

PURPOSE: The purpose of this study was to determine the effects of a 12-wk exercise training program in a predominantly African-American group of stroke survivors with multiple comorbidities. METHODS: A lag-control group design was employed to provide training to all participants (N = 35). Two 12-wk training iterations were arranged. Participants trained 3 d x wk(-1) for 60 min x d(-1) (cardiovascular, 30 min; strength, 20 min; flexibility, 10 min). Outcome measures included peak VO2 (mL x min(-1), mL x kg(-1) x min(-1), maximal workload (MW), time to exhaustion (TTE), 10 RM on two LifeFitness strength machines, grip strength (GS), body weight (BW), total skinfolds (TS), waist to hip ratio (WHR), hamstring/low back flexibility (HLBF), and shoulder flexibility (SF). RESULTS: Compared with controls, the exercise group showed significant gains in peak VO2 (P < 0.01), strength (P < 0.01), HLBF (P < 0.01), and body composition (BW and BMI, P < 0.05; TS, P < 0.01). There was no significant difference between exercise and controls on WHR, SF, and GS. DISCUSSION: A supervised exercise training program for stroke survivors with multiple comorbidities was highly effective in improving overall fitness, potentially reducing the risk of further disease and disability. Greater effort must be made on the part of the public health community to increase access to community-based physical activity programs for persons with stroke.

Black or African American↗
PubMed1999

Structure-activity relationships for a class of inhibitors of purine nucleoside phosphorylase.

Values of inhibition constants, Ki, for a family of structurally related, competitive inhibitors of calf spleen purine nucleoside phosphorylase (PNP) have been determined employing both inosine as substrate and a manual assay and 2-amino-6-mercapto-7-methylpurine ribonucleoside (MESG) as substrate and a robot-based enzyme kinetics facility. Several of the values determined robotically were confirmed employing the same substrate and a manual assay. Surprisingly, for many of the inhibitors examined, values of Ki determined with MESG as substrate are smaller than those obtained employing inosine as substrate by a factor that varies from less than 2 to 10. Values of concentrations required for 50% inhibition of PNP, IC50, have also been determined for the same family of inhibitors employing inosine as substrate. Values of IC50ino and those for Kiino and Kimesg for subsets of the inhibitors have been employed as training sets to create quantitative structure-activity relationships (QSAR) which have substantial power to predict values of IC50 and Ki for inhibitors outside the training set. These QSAR models should be useful in guiding future medicinal chemistry efforts designed to discover inhibitors of PNP having increased potency.

Animals↗
PubMed1999

An electrophysiological exploration of the double crush hypothesis.

The double crush hypothesis has not been rigorously evaluated in humans. We therefore analyzed cases of C6, C7, and C8 radiculopathy and exploited the fact that the median sensory response is of C6/C7 origin and the median motor response is primarily of C8 origin. We hypothesized that C6 and/or C7 cases would demonstrate an increased frequency of median mononeuropathy by sensory criteria, and C8 cases would demonstrate an increased frequency of median mononeuropathy by motor criteria. We also hypothesized that median sensory and motor response parameters among these same groups would be altered in ways consistent with a proximal influence on distal nerve conduction studies. Although median mononeuropathy was unexpectedly common (22.1%) among cases of cervical radiculopathy (which may explain the clinical acceptance of the double crush hypothesis), none of the hypotheses was supported. This study identified no evidence to support a neurophysiological explanation for the double crush hypothesis.

Age Factors↗
PubMed1999

Strategies for ventilatory support.

Since the introduction of manual positive pressure ventilation during the Copenhagen polio epidemic of 1952, a range of mechanical devices and methods of ventilatory support have been developed to provide life-saving respiratory therapy to critically ill patients. In addition to the development of the equipment hardware to enable effective mechanical ventilation, there has been a gradual realisation that a single mode of ventilation is not universally applicable to all patients, individual pathologies, or to individual patients at various stages in the evolution of their pulmonary pathology. While mechanical ventilation can undoubtedly be life-saving, it can also cause lung damage as a result of its non-physiological method of promoting effective gas exchange. This iatrogenic problem is known as ventilator induced lung injury and, although it may be a problem in any patient requiring mechanical ventilation for any reason, is of particular importance to those patients requiring mechanical ventilation as a consequence of trauma. This chapter describes the range of ventilatory support techniques available, the problem of ventilator induced lung injury with specific reference to trauma patients and offers a strategy for ventilatory support in the trauma patient.

Humans↗
PubMed1996

No evidence for linkage of chromosome 22 markers to schizophrenia in southern African Bantu-speaking families.

Previous studies have demonstrated possible linkage between chromosome 22 and one of the hypothesized schizophrenia susceptibility genes. Interpretation of these data, however, is not straightforward: although not significant at the level traditionally accepted to demonstrate linkage, reported lod scores were greater than should have occurred by chance for an unlinked marker based on simulation studies. Further, these studies used sample populations which were either of mixed nationality and ethnicity, or mixed ethnic ancestry from one country. We therefore tested for linkage between highly polymorphic chromosome 22 markers and schizophrenia in a sample of southern African Bantu-speaking black families, a population known to have diverged within the last 2,000 years. We also tested one candidate locus, the gene for the soluble form of catechol-O-methyl transferase (COMT) located at 22q11, which has been suggested as the cause of psychiatric symptoms observed in velo-cardio-facial syndrome (VCFS, including DiGeorge syndrome), and which is known to be functionally as well as genetically polymorphic. There is no evidence to support the linkage of markers on chromosome 22 to susceptibility to schizophrenia in this population, using either parametric or nonparametric analysis.

Catechol O-Methyltransferase↗