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B Jamieson

Publications and source records attributed to B Jamieson.

11 recordsLinked to original sources
PubMed2005

Measurement of the Michel parameter rho in muon decay.

The TWIST Collaboration has measured the Michel parameter rho in normal muon decay, mu(+)--> e(+)nu(e)nu (mu). In the standard model, rho = 3/4. Deviations from this value imply mixing of left- and right-handed muon and electron couplings. We find rho=0.750 80+/-0.000 32(stat) +/- 0.000 97(syst) +/- 0.000 23, where the last uncertainty represents the dependence of rho on the Michel parameter eta. This result sets new limits on the W(L)-W(R) mixing angle in left-right symmetric models.

Journal Article↗
PubMed2003

Effects of asthma on cell components in peripheral blood among smokers and non-smokers.

BACKGROUND: Eosinophils play a central role in asthma, but the interplay of the effects of smoking, eosinophils and asthma remains unclear. OBJECTIVE: The primary objective of our study was to investigate the extent to which smoking modifies the effect of asthma on circulating eosinophils, CD4+ and CD8+ T cell counts. METHODS: Data were collected semiannually between 1987 and 1994 from HIV-negative participants in the Multicenter AIDS Cohort Study. Asthma was defined by a questionnaire at baseline as a self-report of diagnosed asthma. A total of 1420 blood samples from 197 asthmatics and 15 822 from 1997 non-asthmatics were collected. RESULTS: Eosinophil levels were higher in asthmatics (28% of asthmatics had eosinophils >/=4% and 16% of non-asthmatics) regardless of smoking history, but smoking modified the association between eosinophils and asthma. Namely, the odds ratios for eosinophils being >/=4% in asthmatics to non-asthmatics decreased from 2.7 (95% CI: 2.0, 3.6) in never, to 2.1 (1.4, 3.1) in former, and to 1.5 (0.9, 2.3) in current smokers. Cross-sectional and longitudinal analyses coherently showed that smoking increased eosinophils in non-asthmatics, but the converse was true for asthmatics. In contrast, no differences in peripheral blood T cell counts between asthmatics and non-asthmatics were observed. CONCLUSION: Under the established link between increased eosinophils and asthma, these data indicate that smoking modified this relationship. This finding suggests that smoking plays a different immunological role in asthmatics and non-asthmatics.

Adult↗
PubMed1999

Intersubject variability and intrasubject reproducibility of the bereitschaftspotential.

We assessed the intersubject variability and intrasubject reproducibility of the bereitschaftspotential (BP). Twenty healthy volunteers performed extensions of their wrist in a self-paced manner every 5-10 seconds. A surface electromyography (EMG) electrode was attached to the wrist extensor group of the dominant hand to record at least 100 wrist movements, and electroencephalography electrodes were placed over the scalp. Trials were performed at baseline, 15 minutes, 4 hours, and 4 weeks. Measures derived from the BP included area 1 (-2000 to -650 msec), area 2 (-650-0 msec), total area (area 1 + area 2), amplitude at -650 msec, amplitude at peak negativity prior to EMG onset, and amplitude at 0 msec (trigger). Our findings revealed different variability/reproducibility depending on the particular BP measure being analyzed. Using intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC) as measures of intrasubject reproducibility, area 2, amplitude at peak negativity prior to EMG onset, and amplitude at 0 msec produced the best values. We conclude that in studies that attempt to quantify BP changes before and after an intervention in the same group of subjects, the most reproducible BP measures are those pertaining to the late BP component.

Adolescent↗
PubMed1995

Economic impact and clinical benefits of pharmacist involvement on surgical wards.

A one-year pilot project was performed to assess the economic and clinical benefit of pharmacist involvement on the surgical wards of a 600-bed tertiary care, teaching hospital. A total of 405 recommendations were collected with a physician acceptance rate of 90%. From these recommendations, 1416 patient follow-ups were performed to document outcome. The total documented cost avoidance of the pharmacists' activities was $33,265.58. The total annual drug expenditure for the department of surgery declined by $59,662 representing a 9% decrease over the previous year with the greatest decline involving antimicrobials which decreased by $52,587 compared with the previous year. Most of the cost-avoidance in this area was attributable to antimicrobial selection and dosing adjustment in renal impairment. Pharmacist-directed pharmacokinetic monitoring of aminoglycosides resulted in a clinical success rate of 93.8% for treatment regimens and a 6.2% incidence of nephrotoxicity. Housestaff education aimed at improving prescribing practices were identified and provided for select agents including midazolam, ketorolac, vancomycin and aminoglycosides. As well, select recommendations were documented which illustrated the benefit to patient care of pharmacist involvement. Pharmacist involvement on the surgery services produced both financial and clinical benefits.

Canada↗
PubMed1993

The SCID-hu mouse as a model for HIV-1 infection.

During normal fetal ontogeny, one of the first organs to harbour CD4-positive cells is the thymus. This organ could therefore be one of the earliest targets infected by human immunodeficiency virus type 1 (HIV-1) in utero. HIV-1-infected cells and pathological abnormalities of the thymus have been seen in HIV-1-infected adults and children, and in some fetuses aborted from infected women. Studies of HIV-1 pathogenesis have been hampered by lack of a suitable animal model system. Here we use the SCID-hu mouse as a model to investigate the effect of virus infection on human tissue. The mouse is homozygous for the severe combined immunodeficiency (SCID) defect. The model is constructed by implanting human fetal liver and thymus under the mouse kidney capsule. A conjoint human organ develops, which allows normal maturation of human thymocytes. After direct inoculation of HIV-1 into these implants, we observed severe depletion of human CD4-bearing cells within a few weeks of infection. This correlated with increasing virus load in the implants. Thus the SCID-hu mouse may be a useful in vivo system for the study of HIV-1-induced pathology.

Animals↗
PubMed1990

Significance of blasts in low-cell-count cerebrospinal fluid specimens from children with acute lymphoblastic leukemia.

The purpose of this study was to determine whether the presence of more than 5% blasts in a differential count of cytocentrifuged cerebrospinal fluid (CSF) with less than 6 leukocytes/microliter was predictive of central nervous system (CNS) relapse in children with acute lymphoblastic leukemia (ALL). A double concentrate method of cytocentrifuge preparation was used to analyze 4543 consecutive CSF specimens from 349 children with ALL between January 1, 1982, and September 30, 1988. One hundred nine CSF specimens from 58 evaluable children had less than 6 leukocytes/microliter and more than 5% blasts on cytocentrifuge differential count (low-cell-count specimen with blasts [LCB]). During the study period, 25 of 332 evaluable children (7.5%) had CNS leukemic recurrence. In 22 of 25 (88%), the CNS relapse was preceded by at least one abnormal low-cell-count CSF specimen. One of 34 patients with a single LCB at diagnosis (3%) had subsequent CNS relapse compared with five of eight patients (62.5%) with a single LCB during remission (P = 0.0002). Of 16 children with two or more LCB during remission, nine (56%) had CNS relapse defined by standard criteria, whereas six additional patients in this group were declared to be in CNS relapse on the basis of their repetitive LCB. Whether diagnosing CNS recurrence earlier in its course based on a modification of the definition of CNS leukemia will change the frequency of subsequent adverse events or make possible decreased intensity of CNS retreatment remains to be determined.

Adolescent↗
PubMed1990

Heterogeneity of acute "undifferentiated" leukemia of childhood: ultrastructural, immunophenotypic, and karyotypic analyses.

The present study was undertaken in an attempt to reclassify the 19 cases of childhood acute undifferentiated leukemia (AUL) diagnosed at our institution during the past 12 years. Based on ultrastructural and immunophenotypic data, seven of the cases were reclassified as lymphoid, nine as myeloid, and three remain unclassifiable. Clinical features, clonal karyotypes, and responses to treatment were also examined. Abnormal clonal karyotypes were found in 16 of 17 cases, including eight cases with translocations, three with monosomy 7 or 7q, and one with numerous complex structural rearrangements. Fourteen patients had greater than 10% French-American-British L2 blasts in bone marrow. Although nine of 15 patients who initially received induction therapy for acute lymphoblastic leukemia (ALL) achieved remission, only one patient is a long-term survivor. Only one of 10 patients who received therapy for acute nonlymphoblastic leukemia during the course of their disease remains a long-term survivor. These data suggest that the majority of cases of AUL can be reclassified as either myeloid or lymphoid leukemias, that AUL is associated with a high frequency of chromosomal abnormalities, and that AUL carries a very poor prognosis.

Adolescent↗
PubMed1985

Increasing handicapped preschoolers' peer social interactions: cross-setting and component analysis.

The purposes of our study were: (a) to train a set of observationally determined social behaviors via peer initiation; (b) to determine if effects generalized across classroom settings and to directly intervene if generalization did not occur; and (c) to analyze components of the peer-initiation intervention. After baseline, nonhandicapped preschool children (confederates) were taught to direct social initiations to the three handicapped preschool-aged students. Teachers prompted the confederates to engage the students in social interaction when necessary and rewarded the confederates with tokens. Confederates' initiations to the students resulted in increased frequencies of positive social interaction. There was no generalization to other classroom settings, and the intervention was subsequently implemented in a second and third classroom. Next, the confederates' token reinforcement system was withdrawn, with no apparent deleterious effects on the confederates' or students' social interactions. When teachers substantially reduced their prompts to the confederates, students' social interactions decreased. Finally, reinstatement of teacher prompts resulted in increases in the confederates' social initiations and, consequently, the positive social interactions of the students.

Behavior Therapy↗
PubMed1969

Epidural analgesia.

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Anesthesia, Conduction↗