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J Carlson

Publications and source records attributed to J Carlson.

At least 55 records · Page 3Linked to original sources
PubMed2001

Measurement of the top quark p(T) distribution.

We have measured the p(T) distribution of top quarks that are pair produced in pp collisions at sqrt[s] = 1.8 TeV using a sample of tt decays in which we observe a single high- p(T) charged lepton, a neutrino, and four or more jets. We use a likelihood technique that corrects for the experimental bias introduced due to event reconstruction and detector resolution effects. The observed distribution is consistent with the standard model prediction. We use these data to place limits on the production of high- p(T) top quarks suggested in some models of anomalous top quark pair production.

Journal Article↗
PubMed2001

Nicotine produces selective degeneration in the medial habenula and fasciculus retroflexus.

Nicotine's neurotoxic properties in rats were investigated by administering (-)-nicotine tartrate for 5 days either continuously in doses of 5.01, 5.72, 6.44, 7.13, 20.41 and 43.1 mg/kg/day via osmotic minipump or intermittently at 11.32 mg/kg/day via one daily subcutaneous injection. As assessed by silver staining, neurotoxicity was seen almost exclusively in the axons of the medial habenula and its output tract, the fasciculus retroflexus, in all treatment groups except the lowest dose. Within the habenula, the damage was noted in the ventral-medial-most portion of the nucleus which is thought to be dense with the alpha 4 beta 2 and/or alpha 3 beta 4 receptor subtypes. Past research has shown the medial habenula to be highly sensitive to the effects of nicotine, and these findings, in conjunction with related research using dopaminergic stimulants, indicate that the habenula may be a weak link in the neurotoxicity seen following stimulant drugs of abuse.

Animals↗
PubMed2001

Search for neutral supersymmetric Higgs bosons in pp collisions at sqrt[s] = 1.8TeV.

We present the results of a search for neutral Higgs bosons produced in association with b quarks in pp-->bb(phi)-->bbb final states with 91+/-7 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV recorded by the Collider Detector at Fermilab. We find no evidence of such a signal and the data are interpreted in the context of the neutral Higgs sector of the minimal supersymmetric extension of the standard model. With basic parameter choices for the supersymmetric scale and the stop-quark mixing, we derive 95% C.L. lower mass limits for neutral Higgs bosons for tan(beta) values in excess of 35.

Journal Article↗
PubMed2001

Production of chi(c1) and chi(c2) in pp collisions at sqrt[S] = 1.8 TeV.

We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV. The photon from their decay into J/psi(gamma) is reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.

Journal Article↗
PubMed2001

First measurement of the ratio B(t --> Wb)/B(t --> Wq) and associated limit on the Cabibbo-Kobayashi-Maskawa element /V(tb)/.

We present the first measurement of the ratio of branching fractions R identical withB(t-->Wb)/B(t-->Wq) from p_p collisions at sqrt[s] = 1.8 TeV. The data set corresponds to 109 pb(-1) of data recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(+0.31)(-0.24)(stat+syst) or R>0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element /V(tb)/ under the assumption of three generations and unitarity.

Journal Article↗
PubMed2001

Influence of timing of administration of 5-fluorouracil to donors on bone marrow engraftment in nonmyeloablated hosts.

We evaluated the engraftment and the cell cycle status of marrow cells at various times after 5-fluorouracil (5-FU) administration. 5-FU (150 mg/kg) was given to donor male BALB/c mice at 1, 2, 6, or 12 days prior to marrow harvest. The donor cells were then assessed in host nonmyeloablated female mice. Bone marrow engraftment of marrow treated with 5-FU was evaluated and compared to marrow treated with diluent (phosphate-buffered saline) at 3 and 10 weeks after marrow infusion. Our data show a rapid induction of an engraftment defect 1 day after 5-FU, persistence of this defect through day 6, and a recovery by day 12. Experiments using hydroxyurea (which selectively kills cells in the S phase) to determine the cell cycle status indicated that cells that engrafted in post-5-FU marrow were noncycling at days 1, 2, and 12 but cycling at day 6. Post-5-FU bone marrow was also analyzed in vitro by colony assays and its cycling status determined by 3H-thymidine suicide assay. High-proliferative-potential colony-forming cells (HPP-CFCs) and low-proliferative-potential colony-forming cells (LPP-CFCs) decreased rapidly 1 day after 5-FU, with a nadir observed at day 6 for HPP-CFCs and day 2 for LPP-CFCs. By day 12, LPP-CFCs showed a total recovery, but HPP-CFCs were still defective. Significant numbers of HPP-CFCs were cycling, mostly at days 6 and 8 after 5-FU, whereas LPP-CFCs appeared quiescent except at day 2. These results emphasize the importance of timing if post-5-FU marrow is used for gene therapy or marrow transplantation.

Animals↗
PubMed2001

Alpha-1-antitrypsin is present in the specific granules of human eosinophilic granulocytes.

Eosinophils may be found at sites of inflammation, for example in asthma, allergy and helminthic infestation, but their role in human inflammatory disease is unclear. In the present study, we investigated the presence of alpha-1-antitrypsin (AAT), a serine proteinase inhibitor, in human eosinophils. When lysates of highly purified eosinophils were subjected to Western blotting, with a chemiluminescent substrate, immunoreactive bands were seen. An ELISA was developed to measure the AAT content, which was found to be about 100 ng/5 x 106 eosinophils, about 50 ng/5 x 106 neutrophils, and about 25 ng/5 x 106 monocytes. Immunoelectron microscopy showed localization of AAT to the specific granules of eosinophils. During prolonged incubation of eosinophils, no significant increase in the total amount of AAT could be detected by ELISA. However, there was an increased level of AAT in the medium, in parallel with a decrease in the intracellular AAT content, suggesting release of preformed AAT. Apparent complex formation between iodinated elastase and AAT in eosinophil lysates provided evidence that the AAT is functionally active. On the basis of these findings it is suggested that by releasing AAT, eosinophils may, in a microenvironment, play a role in counteracting the tissue damage caused by serine proteinases released by neutrophils in inflammatory conditions.

Cytoplasmic Granules↗
PubMed2001

Documentation of pain assessment and treatment: how are we doing?

The purpose of this analysis was to evaluate documentation of practice provided by a multidisciplinary team of nurses, physicians, and pharmacists who participated in an educational program on postoperative pain management. Chart audit of 787 patient charts at 6 sites revealed documentation of pain histories in approximately 75% of the charts, most often in the surgeon's history and physical examination. Examination of multiple assessment items indicated that the experimental group, relative to the control group, experienced an increase of more than 10% in the documentation of pain intensity, pain quality, pain duration, numeric rating scale used, pain behavior, factors that increase pain, vital signs, sedation level, cognitive status, social interaction, and mood from before the program to 6 months after the program. Across all sites, documentation of assessment, treatment, and treatment outcome data was infrequent and inconsistent. Calculation of documentation of 4 items that constituted a focused assessment of postoperative pain on the surgical floor revealed a significant program effect for assessment of pain quality and pain intensity. A postprogram survey of participants in the educational program revealed an increase in discussion of postoperative pain management with other practitioners and an increase in use of a 0 to 10 scale to rate pain. More documentation of patient pain history, clinical problems, treatment, and follow-up action is needed to improve practice and research.

Clinical Competence↗
PubMed2001

Effects of MgSO4 and glucose, insulin and potassium (GIK) on atrial conduction during the first 12 hours after DC-conversion of chronic atrial fibrillation.

OBJECTIVE: To investigate changes in atrial conduction induced by MgSO4 and glucose, insulin and potassium (GIK) during the first 12-h period of sinus rhythm after successful DC-conversion of chronic atrial fibrillation (CAF). METHODS: Signal-averaged P-wave duration, QRS-duration and PQ-time were recorded in 20 patients who were randomly assigned to control or intervention. Ten patients received no infusates (control group) and 10 patients received MgSO4 and GIK infusions (intervention group). P-wave duration was determined from the X-, Y- and Z-leads, which were further combined to obtain a spatial magnitude. P-wave morphology was studied by analysing global activation patterns and discrete components from the calculated spatial magnitude signal. RESULTS: No changes in the measured parameters were seen in the control group. The P-wave duration, QRS-duration and PQ-time increased from 139(13) [mean(SD)] to 149(15) (p < 0.01), 90(7) to 94(9) (p < 0.05) and 188(10) to 207(13) ms (p < 0.01). respectively, after bolus infusion of MgSO4. The time from the start of the P-wave to its 1st and 2nd max. locations increased by 6 ms (p < 0.01) in both cases after bolus infusion of MgSO4 and had reversed after 10 h of MgSO4 and GIK infusion. P-wave duration and PQ-time decreased after 10 h of MgSO4 and GIK infusion, from 149(34) (bolus) to 138(12) and from 207(13) to 195(27) ms (p < 0.05), respectively, in spite of an even higher serum Mg concentration at the end of this period. CONCLUSION: Bolus infusion of MgSO4 2 h after DC-conversion of CAF produced an intra-atrial conduction delay that could be reversed by adding a GIK infusion, in spite of a concomitant increase in serum Mg concentration. No recovery of the intra-atrial conduction delay, seen after DC-conversion of CAF, was observed in either of the two groups during the 12-h study period.

Aged↗
PubMed2001

Surgical patients' fear of addiction to pain medication: the effect of an educational program for clinicians.

OBJECTIVE: The appropriate and optimal use of analgesics is essential for the adequate management of postoperative pain. Concern that use of opioid analgesics contributes to the development of addiction is a barrier to effective pain relief. The purpose of this study was to determine the prevalence of fear of addiction in postoperative patients in relation to surgical outcomes and staff participation in an educational program. DESIGN: Two treatment levels (program vs. control) and three data collection periods (before program, immediately after the program, and 6 months after the program). SETTING: Six community hospitals with 100-500-bed capacities in a southeastern state. PATIENTS: Seven hundred eighty-seven patients who had undergone orthopedic or laparotomy procedures. INTERVENTIONS: Staff at three of the six hospitals received an educational program to promote implementation of Agency for Health Care Policy and Research acute pain management guidelines. OUTCOME MEASURES: Patient report of preoperative and postoperative fear of addiction, satisfaction with pain treatment, communication with clinicians, and pain intensity. RESULTS: Only 10.8% of the sample reported preoperative or postoperative fear of addiction. Staff participation in the educational program was found to decrease fear of addiction in this sample. Fear of addiction was also related to surgery type, with disc surgery patients more likely to report fear of addiction as compared with patients undergoing other types of surgery. Fear of addiction was not related to other outcomes in this sample. CONCLUSIONS: Fear of addiction is not prevalent among postoperative patients, yet clinician education can further decrease the proportion of surgical patients who fear of addiction to pain medication.

Adolescent↗
PubMed2001

Classification of electrocardiographic P-wave morphology.

The atrial activity of the human heart is normally visible in the electrocardiogram as a P-wave. In patients with intermittent atrial fibrillation, a different P-wave morphology can sometimes be seen, indicating atrial conduction defects. The purpose of this study was to develop a method to discriminate between such P-waves and normal ones. 20 recordings of each type were used in a classification which, based on impulse response analysis of the P-wave and linear discrimination between various parameters, produced a correct classification in 37 of the 40 recordings (sensitivity 95%, specificity 90%).

Atrial Fibrillation↗
PubMed2001

Stem cell engraftment strategies.

The donor stem cell phenotype and host microenvironment determine the outcome of a stem cell transplant. In a series of transplant studies in syngeneic male to female or congenic Ly5.1/Ly5.2 models in which hosts have received no or minimal irradiation (100 cGy), evidence overwhelmingly supports the concept that syngeneic engraftment is determined by stem cell competition. These approaches can be extended to H-2 mismatched allogeneic mouse combination when antigen pre-exposure and CD40-CD40 ligand antibody blockage are employed. A human trial in patients with resistant neoplasia infusing pheresed blood with 10(8) CD3 cells/kg showed that tumor responses and complete chimerism occur with very low levels of CD34+ cells/kg and that the extent of previous treatment is a critical factor in determining chimerism. A major feature of transplants is the phenotype of the donor stem cell. This phenotype shows dramatic reversible plasticity involving differentiation, adhesion protein expression, and engraftment with cytokine-induced cell-cycle transit. Homing is probably also plastic. Marked fluctuations in engraftment capacity are also seen at different points in marrow circadian rhythm.

Adolescent↗
PubMed2001

From paper electrophoresis to computer-supported interpretation of capillary electrophoresis--clinical plasma protein analysis in Malmö, Sweden.

Protein analyses have been used in Malmö as a routine clinical diagnostic tool since 1953. Most serum samples are submitted for "protein profiles" including capillary zone electrophoresis and rate immune nephelometric quantification of nine proteins (five in urines), although analysis of single proteins may be requested. Standardization between laboratories in our region has been greatly improved by automation, CRM 470 calibration and external quality assurance. We are further extending standardization by developing computer supported interpretations using a program with improved user interface and graphical representation of electrophoretic curves superimposed upon a shaded reference interval. Programming is underway to provide complete automatic interpretation of these curves. Together, capillary electrophoresis (with access to mathematical analysis) and immunochemical quantifications allow a highly automated process accessible to further digital analysis and automated interpretation. Rapid, cost-effective and standardized analysis of serum protein profiles should improve the diagnostic evaluation of many categories of patients.

Blood Proteins↗
PubMed2001

Computer-supported detection of M-components and evaluation of immunoglobulins after capillary electrophoresis.

BACKGROUND: Electrophoresis of serum samples allows detection of monoclonal gammopathies indicative of multiple myeloma, Waldenström macroglobulinemia, monoclonal gammopathy of undetermined significance, and amyloidosis. Present methods of high-resolution agarose gel electrophoresis (HRAGE) and immunofixation electrophoresis (IFE) are manual and labor-intensive. Capillary zone electrophoresis (CZE) allows rapid automated protein separation and produces digital absorbance data, appropriate as input for a computerized decision support system. METHODS: Using the Beckman Paragon CZE 2000 instrument, we analyzed 711 routine clinical samples, including 95 monoclonal components (MCs) and 9 cases of Bence Jones myeloma, in both the CZE and HRAGE systems. Mathematical algorithms developed for the detection of monoclonal immunoglobulins (MCs) in the gamma- and ss-regions of the electropherogram were tested on the entire material. Additional algorithms evaluating oligoclonality and polyclonal concentrations of immunoglobulins were also tested. RESULTS: CZE electropherograms corresponded well with HRAGE. Only one IgG MC of 1 g/L, visible on HRAGE, was not visible after CZE. Algorithms detected 94 of 95 MCs (98.9%) and 100% of those visible after CZE. Of 607 samples lacking an MC on HRAGE, only 3 were identified by the algorithms (specificity, 99%). Algorithms evaluating total gammaglobulinemia and oligoclonality also identified several cases of Bence Jones myeloma. CONCLUSIONS: The use of capillary electrophoresis provides a modern, rapid, and cost-effective method of analyzing serum proteins. The additional option of computerized decision support, which provides rapid and standardized interpretations, should increase the clinical availability and usefulness of protein analyses in the future.

Aged↗
PubMed2001

Acute tacrolimus overdose and treatment with phenytoin in liver transplant recipients.

As a potent immunosuppressive agent, Tacrolimus is widely used in organ transplantation. Although complications due to chronic Tacrolimus use are rather well recognized, little is known about acute overdose and its treatment. Phenytoin, an anti-convulsant agent, can induce the Cytochrome P450 enzyme in the liver, which metabolizes Tacrolimus. Therefore, it can be considered as a potential treatment option for acute Tacrolimus toxicity. We hereby report two cases of acute Tacrolimus overdose after Orthotopic Liver Transplantation and the treatment with Phenytoin. Probable mechanisms of metabolism and interactions of these two drugs are discussed and the literature is reviewed.

Child, Preschool↗
PubMed2000

Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV.

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]<P(T)<20 GeV/c and |y|<0.6. For P(T) greater than or approximately equal 12 GeV/c we do not observe significant polarization in the prompt component.

Journal Article↗