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Biomedical subjects

R Olson

Publications and source records attributed to R Olson.

At least 19 recordsLinked to original sources
PubMed2002

HLA class II markers and clinical heterogeneity in Swedish patients with primary biliary cirrhosis.

Genetic susceptibility to PBC can, at least in part, be ascribed to the major histocompatibility complex. The relevance of immunogenetic markers for the clinical presentation and course, however, is unclear. Thus, the aim of this study was to investigate the contribution of HLA class II genes to susceptibility, clinical presentation and course of disease in PBC patients. HLA genotyping for HLA-DRB1, -DQB1 and -DPB1 was carried out in a total of 99 Swedish PBC patients and 158 controls. Clinical parameters including epidemiologic variables, signs and symptoms of PBC-related liver disease and histologic data were collected and analyzed in 92 patients at study entry and at follow-up five years later. Significant clinical heterogeneity was seen among PBC patients upon study entry. Although a significant disease association was seen for HLA DRB1*08 and DQB1*0402, immunogenetic markers identified neither a particular subset of patients nor an association with the clinical course of the disease. HLA-DRB1*08 and DQB1*0402 provide the strongest immunogenetic influence in PBC. However, this association is not restricted to any particular, clinically defined subgroup of patients and it is not predictive for the course of the disease.

Adult↗
PubMed2002

The nematode Anisakis simplex in American shad (Alosa sapidissima) in two Oregon rivers.

This paper represents the first report of the nematode Anisakis simplex in the American shad (Alosa sapidissima) in its introduced range in the American Pacific Northwest. All the adult shad sampled from spawning populations in the Willamette (n = 9) and Umpqua (n = 12) rivers were infected with A. simplex with intensities ranging from 6 to 89 worms per fish. This preliminary investigation contrasts sharply with previous studies in the native range of American shad and confirms that this fish may be an important intermediate host for A. simplex in the Pacific Northwest. It is suggested that this new parasite-host relationship has led to an ecological expansion into rivers and Anisakis may present an emerging health risk for wildlife and some human consumers.

Animals↗
PubMed2001

Mechanisms for ligand binding to GluR0 ion channels: crystal structures of the glutamate and serine complexes and a closed apo state.

High-resolution structures of the ligand binding core of GluR0, a glutamate receptor ion channel from Synechocystis PCC 6803, have been solved by X-ray diffraction. The GluR0 structures reveal homology with bacterial periplasmic binding proteins and the rat GluR2 AMPA subtype neurotransmitter receptor. The ligand binding site is formed by a cleft between two globular alpha/beta domains. L-Glutamate binds in an extended conformation, similar to that observed for glutamine binding protein (GlnBP). However, the L-glutamate gamma-carboxyl group interacts exclusively with Asn51 in domain 1, different from the interactions of ligand with domain 2 residues observed for GluR2 and GlnBP. To address how neutral amino acids activate GluR0 gating we solved the structure of the binding site complex with L-serine. This revealed solvent molecules acting as surrogate ligand atoms, such that the serine OH group makes solvent-mediated hydrogen bonds with Asn51. The structure of a ligand-free, closed-cleft conformation revealed an extensive hydrogen bond network mediated by solvent molecules. Equilibrium centrifugation analysis revealed dimerization of the GluR0 ligand binding core with a dissociation constant of 0.8 microM. In the crystal, a symmetrical dimer involving residues in domain 1 occurs along a crystallographic 2-fold axis and suggests that tetrameric glutamate receptor ion channels are assembled from dimers of dimers. We propose that ligand-induced conformational changes cause the ion channel to open as a result of an increase in domain 2 separation relative to the dimer interface.

Amino Acid Sequence↗
PubMed2000

Effect of 10%, 30%, and 60% body weight traction on the straight leg raise test of symptomatic patients with low back pain.

STUDY DESIGN: Single group test-retest repeated measures. OBJECTIVES: To determine the effects of lumbar traction with 3 different amounts of force (10%, 30% and 60% body weight) on pain-free mobility of the lower extremity as measured by the straight leg raise (SLR) test. BACKGROUND: There are several recommendations on how lumbar traction should be performed, but the duration, frequency, force, and type of technique to be applied differ among the sources. METHODS AND MEASURES: Ten subjects with subjective complaints of low back pain or radicular symptoms with a positive unilateral SLR test below 45 degrees participated in this study. The pain-free mobility of the lower extremity in the SLR test position was measured prior to and immediately following 5 minutes of static traction in the supine position. Random assignment in the order of the amount of applied traction was implemented. RESULTS: The straight leg raise measurements were found to be significantly greater immediately following 30% and 60% of body weight traction as compared to pretraction and 10% of body weight traction. The mean (SD) SLR measurements were pretraction (24.1 degrees +/- 13.0), 10% of body weight traction (27.4 degrees +/- 14.5), 30% of body weight traction (34.0 degrees +/- 14.3), 60% of body weight traction (36.5 degrees +/- 15.8). CONCLUSIONS: The results of this study indicate that traction in this group of patients improved the mobility of the lower extremity during the SLR test. Both 30% and 60% of body weight tractions were shown to be effective for increasing motion beyond pretraction levels.

Adolescent↗
PubMed1999

Crystal structure of staphylococcal LukF delineates conformational changes accompanying formation of a transmembrane channel.

Staphylococcal LukF, LukS, HgammaII, and alpha-hemolysin are self-assembling, channel-forming proteins related in sequence and function. In the alpha-hemolysin heptamer, the channel-forming beta-strands and the amino latch make long excursions from the protomer core. Here we report the crystal structure of the water soluble form of LukF. In the LukF structure the channel-forming region folds into an amphipathic, three-strand beta-sheet and the amino latch forms a beta-strand extending a central beta-sheet. The LukF structure illustrates how a channel-forming toxin masks protein-protein and protein-membrane interfaces prior to cell binding and assembly, and together with the alpha-hemolysin heptamer structure, they define the end points on the pathway of toxin assembly.

Amino Acid Sequence↗
PubMed1998

Treatment with either high or low frequency TENS reduces the secondary hyperalgesia observed after injection of kaolin and carrageenan into the knee joint.

For years, physical therapists have been utilizing a variety of modalities, including transcutaneous electrical nerve stimulation (TENS), in an attempt to manage pain associated with inflammation. However, the data on clinical effectiveness is conflicting and the neurophysiological mechanism of action is not known. The purpose of this study was to investigate the effects of high and low frequency TENS on the secondary hyperalgesia that occurs after joint inflammation. Secondary hyperalgesia is thought to reflect changes in central neurons and is thus a measure of activity of central neurons. This study utilized the kaolin and carrageenan model of knee joint inflammation and measured the effects of TENS treatment on paw withdrawal latency to radiant heat (secondary hyperalgesia), spontaneous pain behaviors and joint circumference. Either high (100 Hz) or low (4 Hz) frequency TENS was applied to the knee joint for 20 min after the development of hyperalgesia. Both high and low frequency TENS resulted in a reversal of the hyperalgesia immediately following treatment. The effects of high frequency TENS lasted through at least 24 h while those of low frequency TENS lasted through 12 h. There was no effect of TENS on spontaneous pain behaviors or joint swelling when compared to controls. Thus, TENS appears to be more effective in reducing referred pain (or secondary hyperalgesia) without affecting guarding or splinting of the affected limb. Thus, clinically, the choice to use TENS may depend on patient symptoms; specifically TENS should be effective in reducing referred or radiating pain.

Animals↗
PubMed1998

XV454, a novel nonpeptide small-molecule platelet GIIb/IIIa antagonist with comparable platelet alpha(IIb)beta3-binding kinetics to c7E3.

XV454 demonstrated high potency (IC50 = 14-25 nM) in inhibiting human platelet aggregation induced by adenosine diphosphate (ADP, 10 microM), thrombin receptor agonist peptide (TRAP) (10 microM), or collagen (20 microg/ml). XV454 exhibited a high degree of selectivity for platelet alpha(IIb)beta3 in comparison with c7E3, which is a nonspecific antagonist for both alpha(IIb)beta3 and alpha(v)beta3. Both XV454 and c7E3 bind with high affinity to either activated (A) or unactivated (U) human, baboon, or canine platelets. XV454 binds with a relatively higher affinity [Kd = 0.5 nM (A), 0.6 nM (U)] as compared with c7E3 [Kd = 9.1 nM (A), 9.2 (U) nM]. XV454 demonstrated a tight association with human, baboon, and, to a lesser extent, with canine platelets (t(1/2) of dissociation = 110 +/- 6, 80 +/- 10, and 23 +/- 2 min, respectively). Both c7E3 and XV454 associate tightly with a slower dissociation rate with unactivated human platelets: t(1/2) of 42 and 116 min, respectively. In non-human primates, oral (0.1 mg/kg, p.o.) and intravenous (0.05 mg/kg, i.v. bolus administration of XV454 methyl ester pro-drug resulted a long-lasting maximal antiplatelet efficacy for < or = 72 h with significant but reversible prolongation of bleeding time and without effects on platelet count, clinical chemistry, or hemodynamic profile. In conclusion, XV454 represents a potent antiplatelet agent in inhibiting platelet aggregation along with a high affinity and relatively slow dissociation rate from human platelet GPIIb/IIIa receptors that allow a long-lasting antiplatelet efficacy after single i.v. or oral administration.

Alanine↗
PubMed1998

Stability of the MCMI-III in a substance-abusing inpatient sample.

The stability of the MCMI-III personality disorder and clinical syndrome scales was assessed in a substance-abusing inpatient sample of 35 African-American men over an average test-retest interval of 6 mo. Estimates were higher for the personality pattern scales than for the clinical syndrome scales. The Dependent personality pattern scale (.83) and the Narcissistic personality pattern scale (.80) were reliable after about six months, whereas Drug Abuse, Somatoform, and Major Depression showed lower stability. As in previous research using the MCMI-I/II, estimates were lower than those reported in the test manual.

Adult↗
PubMed1997

Assessing PTSD with the Millon Clinical Multiaxial Inventory-III.

We studied the utility of the Millon Clinical Multiaxial Inventory-III (MCMI-III) in assessing substance-abusing (n = 228), combat-related PTSD patients (n = 32). The MCMI-III produced a code type (16A) that was quite different from MCMI-I and MCMI-II code types (8A2) among similar populations. The PTSD Scale (R) successfully differentiated between a PTSD and non-PTSD substance-abusing group using mean Base Rate scores, was the best predictor of PTSD in a multiple regression equation, and the scale's sensitivity and specificity in detecting and/or ruling out the disorder was above that provided by chance alone and higher than the values reported in the test manual for that scale. The MCMI-III may be used as a broad band screening instrument for PTSD, at least among patients with combat-related stress.

Adult↗
PubMed1997

Treatment of early rheumatoid arthritis with minocycline or placebo: results of a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To determine if minocycline is an effective therapy for seropositive rheumatoid arthritis (RA) when used within the first year of disease. METHODS: The Rheumatoid Arthritis Investigational Network enrolled 46 patients with RA of <1 year duration into a 6-month study of minocycline (100 mg twice daily) versus placebo. All patients were rheumatoid factor positive. The primary end point of the study was successful completion of 6 months of treatment with no drug toxicity while maintaining 50% improvement in composite symptoms of arthritis. RESULTS: Eighteen of the 46 patients who were enrolled met 50% improvement criteria at 3 months, and maintained at least a 50% improvement for 6 months with no significant drug toxicity. Among them were 15 of the 23 patients (65%) treated with minocycline and 3 of 23 patients (13%) treated with placebo (P < 0.001). CONCLUSION: In patients with early seropositive RA, therapy with minocycline is superior to placebo.

Adult↗
PubMed1997

Long-term efficacy and safety of dronabinol for acquired immunodeficiency syndrome-associated anorexia.

We studied the effects of long-term (12 months) dronabinol in 94 late-stage acquired immunodeficiency syndrome (AIDS) patients (mean CD4 count of 45/mm3) who previously participated in a 6-week study (placebo versus dronabinol). All patients received dronabinol orally-2.5 mg twice daily (90%) or 2.5 mg once daily (10%). Appetite was measured using a visual analogue scale for hunger (VASH). Dronabinol was associated with consistent improvement in mean appetite. Patients previously treated with dronabinol continued to show improvement in VASH (percent change from baseline of 6-week trial: 48.6-76.1% at each month), whereas those previously treated with placebo exhibited substantial improvement in mean appetite, particularly during the initial 4 months of treatment (48.5-69.9%). Thereafter, dronabinol was associated with a VASH change at least twice baseline. Patients tended toward stable body weight for at least 7 months. Adverse events were primarily related to known central nervous system effects of dronabinol. These data support long-term, safe use of dronabinol for anorexia associated with weight loss in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Clinical evaluation of the Unfolder.

PURPOSE: To evaluate the clinical acceptability of the Unfolder for implantation of AMO PhacoFlex II (model SI-30NB or SI-40NB) intraocular lenses (IOLs). SETTING: Six investigational sites in five states in the United States: Utah, Texas, Missouri, Minnesota, and Massachusetts. METHODS: One hundred one patients from six investigational sites had implantation of an SI-30NB or SI-40NB IOL. Investigators evaluated the clinical acceptability of the Unfolder by comparing their experience with the injector with that using other implantation systems. Internal incision size (dimensions) was measured three times during surgery using a calibrated instrument. Data on safety and efficacy were collected. RESULTS: The investigators rated the Unfolder as clinically acceptable. Mean internal incision size after phacoemulsification but before IOL implantation was 3.0 mm +/- 0.1 (SD) (range 2.7 to 3.2 mm). Average internal incision size after IOL implantation was 3.1 +/- 0.1 mm. There were no reports of haptic deformation, lens optic damage, or postoperative complications related to the Unfolder. No adverse events were reported. CONCLUSIONS: Investigators found the Unfolder easy to use. It provided controlled lens implantation through incisions 2.7 to 3.2 mm, with post-IOL implantation incisions ranging from 2.9 to 3.3 mm.

Evaluation Studies as Topic↗
PubMed1997

MCMI-III-derived typological analysis of cocaine and heroin addicts.

A sample of 441 African American men who were either inpatient heroin or cocaine addicts, or both; were assessed with the MCMI-III. The modal codetype showed primary elevations on the Antisocial Personality Disorder Scale (6A), consistent with previous research using the MCMI-I and MCMI-II with substance abusers. The data were subjected to 3 independent clustering procedures that resulted in general consistency among procedures. The solutions were validated on a randomly selected half of the sample. Three subtypes were variants of the antisocial parent codetype, whereas another subtype was characterized by a Within Normal Limits profile suggesting no personality disorder. These 4 subtypes were also associated with different external correlates with significant clinical import. The results suggest that findings from previous research with substance-abusing patients, using the MCMI-I and MCMI-II, should be applicable to the MCMI-III as well.

Adult↗
PubMed1996

Homelessness, negative affect, and coping among veterans with gambling problems who misused substances.

Compared with other populations with addictions, pathological gamblers have higher levels of negative affect and poor coping. A total of 154 formerly homeless veterans who misused substances were assessed six months after treatment to determine whether those with a gambling problem (N = 22) had more negative affect and poorer coping than those without a gambling problem and whether they were more likely to have unstable housing and employment. The veterans with a gambling problem had significantly higher levels of negative affect and poorer coping but did not differ from the other veterans in housing and employment stability.

Adaptation, Psychological↗
PubMed1996

Drugs, athletes, and family physicians. When to withhold medications and when to document prescriptions.

Sport governing bodies restrict drug use by athletes. Family physicians need to know which common medications are banned or restricted, and what documentation of treatment is necessary. The formidable list of banned and restricted substances and methods can be distilled to manageable guidelines for situations often faced by family physicians treating patient-athletes.

Drug Prescriptions↗
PubMed1995

Dronabinol as a treatment for anorexia associated with weight loss in patients with AIDS.

The effects of dronabinol on appetite and weight were evaluated in 139 patients with AIDS-related anorexia and > or = 2.3 kg weight loss in a multi-institutional study. Patients were randomized to receive 2.5 mg dronabinol twice daily or placebo. Patients rated appetite, mood, and nausea by using a 100-mm visual analogue scale 3 days weekly. Efficacy was evaluable in 88 patients. Dronabinol was associated with increased appetite above baseline (38% vs 8% for placebo, P = 0.015), improvement in mood (10% vs -2%, P = 0.06), and decreased nausea (20% vs 7%; P = 0.05). Weight was stable in dronabinol patients, while placebo recipients had a mean loss of 0.4 kg (P = 0.14). Of the dronabinol patients, 22% gained > or = 2 kg, compared with 10.5% of placebo recipients (P = 0.11). Side effects were mostly mild to moderate in severity (euphoria, dizziness, thinking abnormalities); there was no difference in discontinued therapy between dronabinol (8.3%) and placebo (4.5%) recipients. Dronabinol was found to be safe and effective for anorexia associated with weight loss in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1995

AHA responds to proposals on medical waste incineration.

Roger Olson, chairman of facilities operations for the Mayo Clinic, Rochester, MN, testified on behalf of the American Hospital Association before the U.S. Environmental Protection Agency's Office of Air Quality Planning and Standards on the EPA's proposed rules on medical waste incinerators. Here's what he had to say.

American Hospital Association↗