Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Statistical Regression”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1990

Serum 5'nucleotidase activity in rats: a method for automated analysis and criteria for interpretation.

A manual kit for determining serum 5'nucleotidase (5'NT, EC 3.1.3.5) activity was adapted for use with rat samples on a large discrete clinical chemistry analyzer. The precision of the method was good (within-run C.V. = 2.14%; between-run C.V. = 5.5%). A comparison of the new automated method with a manual and semi-automated method gave regression statistics of y = 1.18X -3.66 (Sy. x = 4.54), and y = 0.733X + 1.97 (Sy. x = 1.69), respectively. Temperature conversion factors provided by the kit manufacturer for human samples were determined to be inaccurate for converting results from rat samples. Analysis of components contributing to normal variation in rat serum 5'NT activity showed age and sex to be major factors. Increased serum 5'NT activity was observed in female rats when compared to male rats beginning at about 5 to 6 weeks of age. An analysis of variance of serum 5'NT, alkaline phosphatase, and GGT activities observed over a 9-week period in normal rats suggests several advantages for 5'NT as a predictor of biliary lesions in rats.

Journal Article↗
PubMedDate not supplied

Hospital accreditation and patient satisfaction: testing the relationship.

This article describes a study that examines the relationship between two principal measures of institutional healthcare quality: accreditation scores and independently measured patient-satisfaction ratings. This study involved a retrospective review and comparison of summative and selected categorical hospital accreditation scores from the Joint Commission on Accreditation of Healthcare Organizations and independently measured patient satisfaction ratings. A total of 41 acute care, 200-plus bed, not-for-profit hospitals in New Jersey and eastern Pennsylvania were included. Correlation and multiple-regression statistical methods were employed. The results revealed no relationship between these quality indicators on a summative level and no meaningful pattern categorical relationships. This finding suggests a disassociation between these two quality indicators, thus supporting the use of a balanced scorecard approach to hospital quality management. The study also revealed certain shortcomings in these two quality indicators, relating to insufficient score variability, which should be considered by those using such data to manage quality outcomes.

Accreditation↗
PubMed2002

Factors underlying the speech-recognition performance of elderly hearing-aid wearers.

This paper reports the aided and unaided speech-recognition scores from a group of 171 elderly hearing-aid wearers. All hearing-aid wearers were fit with identical instruments (linear Class-D amplifiers with output-limiting compression) and evaluated with a standard protocol. In addition to including multiple measures of speech recognition, an extensive set of physiological and perceptual measures of auditory function, as well as general measures of cognitive function, were completed prior to the hearing-aid fitting. Comparison of the results from this study to available norms suggested that this group of participants was fairly typical or representative for their hearing loss and age. Approaches to the prediction of general speech-recognition performance that were examined included methods based on an acoustical index, the Speech Intelligibility Index (SII), and others based on linear-regression statistical analysis. The latter approach proved to be the most successful, accounting for about two-thirds of the variance in speech-recognition performance, with the primary predictive factors being measures of hearing loss and cognitive function.

Aged↗
PubMed1989

Pharmacokinetic comparison of 5 g of azlocillin every 8 h and 4 g every 6 h in healthy volunteers.

To compare the multiple-dose pharmacokinetics of two dosage regimens of azlocillin, we studied 12 healthy volunteers via a randomized, crossover design with a 2-week washout phase between regimens. Serum and urine samples were collected for 8 h following the fifth dose of a regimen of 4 g every 6 h and the fourth dose of a regimen of 5 g every 8 h. Data for concentrations in serum were fitted to a two-compartment open model by nonlinear regression. Statistically significant differences (P less than 0.05) were observed in the following parameters (mean +/- standard deviation) for the 4- and 5-g regimens, respectively: area under the serum concentration-time curve during the dosing interval, 592 +/- 140 versus 772 +/- 151 micrograms.h/ml; terminal elimination rate constant, 0.5364 +/- 0.0912 versus 0.4758 +/- 0.0486 h-1; renal clearance, 87.6 +/- 16.1 versus 76.1 +/- 13.5 ml/min; maximum drug concentration in serum, 381 +/- 89 versus 473 +/- 90 micrograms/ml; and minimum drug concentration in serum, 19 +/- 10 versus 8 +/- 4 micrograms/ml. No significant differences were seen in the following parameters: V1, V beta, k10, k12, k21, total systemic clearance, and nonrenal clearance. These data support the presence of saturable renal elimination of azlocillin, as well as the feasibility of an 8-h dosing interval.

Adult↗
PubMed2006

Use of fluconazole as a surrogate marker to predict susceptibility and resistance to voriconazole among 13,338 clinical isolates of Candida spp. Tested by clinical and laboratory standards institute-recommended broth microdilution methods.

Clinical laboratories frequently face the problem of delayed availability of commercially prepared approved reagents for performing susceptibility testing of new antimicrobials. Although this problem is encountered more often with antibacterial agents, it is also an issue with antifungal agents. A current example is voriconazole, a new triazole antifungal with an expanded spectrum and potency against Candida spp., Aspergillus spp., and other opportunistic fungal pathogens. The present study addresses the use of fluconazole as a surrogate marker to predict the susceptibility of Candida spp. to voriconazole. Reference broth microdilution MIC results for 13,338 strains of Candida spp. isolated from more than 200 medical centers worldwide were used. Voriconazole MICs and interpretive categories (susceptible, < or =1 microg/ml; susceptible dose dependent, 2 microg/ml; resistant, > or =4 microg/ml) were compared with those of fluconazole by regression statistics and error rate bounding analyses. For all 13,338 isolates, the absolute categorical agreement was 91.6% (false susceptible or very major error [VME], 0.0%). Since voriconazole is 16- to 32-fold more potent than fluconazole, the performance of fluconazole as a surrogate marker for voriconazole susceptibility was improved by designating those isolates with fluconazole MICs of < or =32 microg/ml as being susceptible to voriconazole, resulting in a categorical agreement of 97% with 0.1% VME. Clinical laboratories performing antifungal susceptibility testing of fluconazole against Candida spp. can reliably use these results as surrogate markers until commercial FDA-approved voriconazole susceptibility tests become available.

Antifungal Agents↗
PubMed1988

Quantitation of indirect sandwich enzyme-linked immunosorbent assay parameters.

The optimization of data from the indirect sandwich enzyme-linked immunosorbent assay has been commonly accomplished by linear regression analysis, even though the data are often essentially sigmoid. A new microcomputer software program (LISACRV) that uses a nonlinear regression statistical model to analyze the data from enzyme-linked immunosorbent assay titration experiments was developed.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Disk diffusion test interpretive criteria and quality control recommendations for testing linezolid (U-100766) and eperezolid (U-100592) with commercially prepared reagents.

Two new oxazolidinones were tested to determine interpretive susceptibility testing criteria for MIC and disk diffusion methods. Commercial lots of linezolid (formerly U-100766) and eperezolid (formerly U-100592) disks containing 30 microg of drug were tested against 728 isolates of bacteria with defined mechanisms of resistance. Results from linezolid were highlighted because of its choice for clinical development. By using preliminary pharmacokinetic data, a tentative susceptibility breakpoint of < or = 4 microg/ml was selected. Corresponding breakpoint zone diameters for linezolid were > or = 21 mm (< or = 4 microg/ml) for susceptibility and < or = 17 mm (> or = 16 microg/ml) for resistance. Regression statistics demonstrated a high correlation coefficient (r > or = 0.98), and absolute categorical agreement between methods was obtained, when staphylococci and enterococci were tested with the cited criteria. When Streptococcus spp. (including S. pneumoniae) were tested, only the susceptibility breakpoint was suggested. Quality control (QC) guidelines for linezolid disk diffusion tests were established by a multilaboratory trial as follows: 27 to 31 mm for Staphylococcus aureus ATCC 25923 and 28 to 34 mm for S. pneumoniae ATCC 49619. More than 95% of all QC results were within these proposed ranges. Although not advanced to clinical trials, eperezolid demonstrated potency comparable to that of linezolid and had identical interpretive testing criteria. These preliminary interpretive criteria and QC limits (accepted by the National Committee for Clinical Laboratory Standards) should be applied to linezolid tests during the clinical-trial phases of oxazolidinone drug development in order to ensure test accuracy and reproducibility.

Acetamides↗
PubMed2004

Cross-resistance between fluconazole and ravuconazole and the use of fluconazole as a surrogate marker to predict susceptibility and resistance to ravuconazole among 12,796 clinical isolates of Candida spp.

Cross-resistance within a class of antimicrobial agents is a problem that is often encountered with antibacterial agents, and it is also an issue with antifungal agents. A current example is ravuconazole, a new triazole antifungal with an expanded spectrum and potency against Candida spp., Aspergillus spp., and other opportunistic fungal pathogens. The present study addresses the issue of cross-resistance between fluconazole and ravuconazole and the use of fluconazole as a surrogate marker to predict the susceptibility of Candida spp. to ravuconazole. Reference broth microdilution MIC results for 12,796 strains of Candida spp. isolated from more than 200 medical centers worldwide were used. Ravuconazole MICs and tentative interpretive categories (susceptible, </=1 microg/ml; resistant, >/=2 microg/ml) were compared with those of fluconazole by using regression statistics and error rate bounding analyses. For all 12,796 isolates, the absolute categorical agreement rate was 92.5% (rate of false-susceptible results, or very major errors [VME], 0.1%). Ravuconazole was active (MIC, </=1 microg/ml) against 99.9% of the fluconazole-susceptible isolates, 96% of the fluconazole-susceptible dose-dependent isolates, and 49% of the fluconazole-resistant isolates, including 99% of the Candida krusei isolates. Since ravuconazole is 16- to 32-fold more potent than fluconazole, the performance of fluconazole as a surrogate marker for ravuconazole susceptibility was improved by designating those isolates with fluconazole MICs of </=32 microg/ml susceptible to ravuconazole, resulting in a categorical agreement rate of 98.3%, with a VME rate of 0.3% (99 and 0.4%, respectively, when C. krusei was omitted). Cross-resistance between fluconazole and ravuconazole applies most directly to fluconazole-resistant Candida glabrata and is variable among other species of Candida. Fluconazole may serve as a surrogate marker to predict the susceptibility of Candida spp. to ravuconazole.

Antifungal Agents↗
PubMed1979

Polyoma DNA synthesis in isolated nuclei: evidence for defective replication forks.

Nuclei, isolated from polyoma virus-infected mouse 3T6 cells, were incubated under condtions suitable for polyoma DNA synthesis. By using electrom microscopy and standard regression statistics, it was shown that replication is mainly unidirectional in a large number of molecules, indicating the presence of inactive replication forks. The replication forks were inactivated randomly, and the defect seemed to be present from the beginning of the in vitro incubation.

Animals↗
PubMed1989

Effects of hepatic blood flow on hepatic ethanol kinetics measured in cats and predicted from the parallel tube model.

In cats anesthetized with pentobarbital, a long-circuit technique was used to measure hepatic blood flow while portal flow was varied from 0 to 300% of normal in random steps. Arterial, portal, and hepatic venous blood samples were analyzed for ethanol concentrations during continuous infusion of ethanol (20 mumol/(min.kg body weight) into the reservoir. Measured values for logarithmic mean sinusoidal ethanol concentration, hepatic venous ethanol concentration, hepatic ethanol uptake, and ethanol extraction were compared with the values predicted by the parallel tube model for hepatic uptake of substrates using Vmax and Km determined in each cat at the start of the experiment. Measured and predicted values were very similar at all blood flows above 65% control, but statistical regression analysis indicated a small but highly significant deviation of the measured values from the predicted values. At low flows, measured values of logarithmic mean sinusoidal and hepatic venous concentrations markedly exceeded the predicted values in most cats. The results indicate that the parallel tube model, which assumes all sinusoids are identical and equally perfused, provides a useful approximation for the effects of hepatic blood flow on hepatic ethanol kinetics except at low flows. However, there appears to be a significant degree of sinusoidal heterogeneity that results in a better fit to the distributed model. Our previously reported data for hepatic galactose uptake followed a similar pattern when reanalyzed in this more rigorous way.

Animals↗
PubMed2003

Multi-detector row CT: radiation dose characteristics.

PURPOSE: To determine the dose characteristics of multi-detector row computed tomography (CT) and to provide tabulated dose values and rules of thumb that assist in minimizing the radiation dose at multi-detector row CT. MATERIALS AND METHODS: Weighted CT dose index (CTDI100w) values were obtained from three multi-detector row CT scanners (LightSpeed; GE Medical Systems, Milwaukee, Wis) for both head and body CT modes by using standard CT-dose phantoms. The CTDI100w was determined as a function of x-ray tube voltage (80, 100, 120, 140 kVp), tube current (range, 50-380 mA), tube rotation time (0.5-4.0 seconds), radiation profile width (RPW) (5, 10, 15, 20 mm), and acquisition mode (helical high-quality and high-speed modes and axial one-, two-, and four-section modes). Statistical regression was performed to characterize the relationships between CTDI100w and various technique factors. RESULTS: The CTDI100w (milligray) increased linearly with tube current: in head mode, CTDI100w = (0.391 mGy/mA +/- 0.004) x tube current (milliampere) (r2 = 0.999); in body mode, CTDI100w = (0.162 mGy/mA +/- 0.002) x tube current (milliampere) (r2 = 0.999). The CTDI100w increased linearly with rotation time: in head mode, CTDI100w = (34.7 mGy/sec +/- 0.2) x rotation time (seconds) (r2 = 1.0); in body mode, CTDI100w = (13.957 mGy/sec +/- 0.005) x rotation time (seconds) (r2 = 1.0). The relationship of normalized CTDI100w (milligrays per 100 mAs) with tube voltage followed a power law: in head mode, CTDI100w = (0.00016 mGy/100 mAs. kVp +/- 0.00007) x (tube voltage)(2.5+/-0.1) (r2 = 0.997); in body mode, CTDI100w = (0.000012 mGy/100 mAs. kVp +/- 0.000007) x (tube voltage)(2.8+/-0.1) (r2 = 0.996). In all scanning modes, CTDI100w decreased when RPW increased. CTDI100w was 10% higher in head mode and 13% lower in body mode compared with the value suggested by the manufacturer, which is displayed at the scanner console. When deposited power exceeded 24 kW, CTDI100w increased by 10% as a result of use of the large focal spot. CONCLUSION: The authors provide a set of tables of radiation dose as a function of imaging protocol to facilitate implementation of radiation dose-efficient studies.

Head↗
PubMed1994

Mechanical actions of heterogenic reflexes linking long toe flexors with ankle and knee extensors of the cat hindlimb.

1. To study the means whereby ankle biomechanics are represented in the interneuronal circuitry of the spinal cord we examined stretch-evoked reflex interactions between the physiological extensors flexor hallucis longus (FHL) and flexor digitorum longus (FDL) as well as their interactions with gastrocnemius (G), soleus (S), and the quadriceps group (Q) in 34 unanesthetized decerebrate cats. To evoke stretch, DC motors provided ramp-hold-release length changes to tendons detached from their bony insertions. Semiconductor myographs measured resultant muscle force response. Reflexes were examined under both quiescent (no active force generation) and activated conditions; muscle activation was achieved through either crossed-extension or flexion reflexes. 2. FHL and FDL share mutual excitatory stretch-evoked interactions under most conditions examined. These interactions depended on muscle length, were asymmetric (with FHL contributing a larger magnitude of reflex excitation onto FDL), and occurred at a latency of 16 ms. Mutual Ia synergism previously described for these two muscles provides a basis for all of the above findings. Our data demonstrate that for this muscle pair, reflex connectivities revealed at the intracellular level can be extrapolated to cover the entire motoneuron pool; further, our data directly demonstrate the net mechanical result of ensemble synaptic events. 3. FHL was found to share strong, mutually inhibitory stretch-evoked interactions with G, S, and Q. Stepwise regression statistical analyses determined that these interactions depended on recipient muscle force and donor muscle force. These reflex interactions all occurred at a latency of 28 +/- 4 (SE) ms. Further, the heterogenic inhibition between FHL/G and FHL/S was attenuated by strychnine infusion (intravenous) but unaffected by either mecamylamine, picrotoxin, or baclofen infusion (intravenous, intrathecal). Disynaptic Ib inhibition previously described among hindlimb extensors provides a basis for the above findings; our data demonstrate that under certain conditions the ensemble activity of this system can cause a dramatic decline in whole muscle force output. 4. By contrast, FDL was found to share mutually inhibitory, stretch-evoked reflex interactions with G, S, and Q that were much weaker than those observed between FHL and these same muscles. The small magnitude of inhibition observed in these interactions made it difficult to assess reflex latency or to determine the factor(s) that best predicted the heterogenic inhibition. 5. This study provides further evidence of intrinsic differences in interneuronal organization between muscles whose activity occurs in a periodic manner during locomotion ("stereotypical") and a muscle whose locomotor activity is characterized by both periodic and nonperiodic components ("facultative").(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed2006

Phase I trial of a novel intradermal idiotype vaccine in patients with advanced B-cell lymphoma: specific immune responses despite profound immunosuppression.

The immunoglobulin receptor of B-cell lymphomas constitutes a specific tumor antigen (idiotype) and a target for active immunotherapy. Encouraging results have been reported in phase II trials after s.c. vaccination of follicular lymphoma patients during clinical remission with idiotype produced from eukaryotic cell lines and coupled to an immunogenic carrier macromolecule. We have developed a good manufacturing protocol for rapid expression of idiotype vaccines as recombinant Fab fragments in Escherichia coli. The objectives of this trial were to show safety and feasibility of intradermal immunization with this vaccine and to investigate whether immune responses were induced by this immunization route. Patients (n = 18) with advanced B-cell malignancies received repetitive intradermal vaccinations with 0.5 to 1.65 mg recombinant idiotype Fab fragment mixed with lipid-based adjuvant in combination with 150 mug granulocyte macrophage colony-stimulating factor s.c. at the same location. The patients' immune status was assessed by flow cytometry of peripheral blood lymphocytes and concomitant hepatitis B vaccination. Cellular and humoral immune responses to the vaccine were assessed by enzyme-linked immunospot and ELISA. Side effects of a total of 65 vaccinations were mild and did not affect the immunization schedule. No patient developed hepatitis B surface antibodies (anti-HBs) after two hepatitis B immunizations. Of 17 evaluable patients, five developed specific anti-vaccine antibodies, and eight developed anti-Fab T-cell responses. T-cell reactivity was independent of the cellular immune status and was idiotype specific as shown by statistical regression analysis (P = 0.0024) and epitope mapping studies. Intradermal administration of uncoupled recombinant idiotype with appropriate adjuvants may overcome profound clinical immunosuppression and induce specific immune responses.

Adult↗
PubMed2003

Chlamydia pneumoniae in elderly patients with stroke (C-PEPS): a case-control study on the seroprevalence of Chlamydia pneumoniae in elderly patients with acute cerebrovascular disease.

BACKGROUND AND PURPOSE: Multiple studies have suggested an association between Chlamydia pneumoniae infection and atherosclerotic vascular disease. We investigated whether serological markers of C. pneumoniae infection were associated with acute stroke or transient ischaemic attack (TIA), exclusively in elderly patients. METHODS: One-hundred white patients aged over 65 years admitted with acute stroke or TIA, and 87 control patients admitted with acute non-cardiopulmonary, non-infective disorders were recruited prospectively. Using an enzyme-linked immunosorbent assay kit, the presence of C. pneumoniae immunoglobulins IgA, IgG, IgM in patients' sera was determined. RESULTS: The seroprevalence of C. pneumoniae-specific IgA, IgG, IgM were 63, 71, and 14% in the stroke/TIA group (median age = 80), and 62, 65, and 17% in the control group (median age = 80), respectively. Using a logistic regression statistical model, adjusting for age and sex, history of hypertension, smoking, diabetes, ischaemic heart disease (IHD), ischaemic electrocardiogram (ECG), the odds ratios (ORs) of having a stroke/TIA in relation to C. pneumoniae-specific IgA, IgG, IgM were 1.04, 1.24, 0.79 (p = NS). Further analysis identified 43 acute stroke/TIA cases and 44 controls without history of IHD or ischaemic ECG or both. After adjusting for history of hypertension, smoking, diabetes, age and sex, the ORs in this subgroup were 1.40 for IgA [95% confidence interval (CI) 0.53-3.65; p = 0.49], 2.41 for IgG (95% CI 0.90-6.46; p = 0.08) and 1.55 for IgM (95% CI 0.45-5.40; p = 0.49). CONCLUSIONS: Although a high seroprevalence of C. pneumoniae in elderly patients was confirmed, no significant association between serological markers of C. pneumoniae infection and acute cerebrovascular events was found. There was, however, a weak trend towards increased ORs for acute cerebrovascular disease in a subgroup of C. pneumoniae seropositive elderly patients without any history of IHD or ischaemic ECG.

Acute Disease↗
PubMed2004

Mycoplasma pneumoniae in elderly patients with stroke. a case-control study on the seroprevalence of M. pneumoniae in elderly patients with acute cerebrovascular disease - the M-PEPS Study.

BACKGROUND AND PURPOSE: Previous studies have suggested certain infections as potential risk factors for stroke. Chlamydia pneumoniae, an atypical respiratory pathogen, has been linked to atherosclerotic vascular diseases. Mycoplasma pneumoniae, another atypical respiratory micro-organism, can rarely cause stroke. We investigated whether serological markers of M. pneumoniae infection were associated with acute stroke or transient ischaemic attack (TIA) in elderly patients. METHODS: This case-control study was nested within the C-PEPS study - a case-control study on the seroprevalence of C. pneumoniae in elderly stroke and medical patients. Ninety-five incident cases of patients admitted consecutively with acute stroke or TIA, and 82 control subjects admitted concurrently with acute non-cardiopulmonary, non-infective disorders, were included in this study (both groups aged 65 years or older). Using commercial enzyme-linked immunosorbent assay (ELISA) kits, the presence of M. pneumoniae immunoglobulins IgA, IgG and IgM in patients' sera was determined. RESULTS: The seroprevalence of M. pneumoniae IgA, IgG and IgM in the stroke or TIA group (median age = 80) were 79, 61 and 6%, respectively. In the control group (median age = 80), the seroprevalence of respective M. pneumoniae IgA, IgG and IgM were 84, 50 and 11%. Using a logistic regression statistical model, adjusting for history of hypertension, smoking, diabetes mellitus, age and sex, history of ischaemic heart disease, and ischaemic electrocardiogram, the odds ratios of having a stroke or TIA in relation to M. pneumoniae IgA, IgG and IgM were 0.63 (95% confidence interval (CI) = 0.26-1.52, p = 0.31), 1.32 (95% CI = 0.66-2.64, p = 0.43) and 0.52 (95% CI = 0.14-1.92, p = 0.32), respectively. CONCLUSIONS: The study showed a high seroprevalence of M. pneumoniae in an elderly hospital population, using ELISA. Although the study ruled out M. pneumoniae seropositivity as a major risk factor for stroke in this elderly population, a smaller effect could not be excluded due to the small sample size. Future larger studies may be required to determine the precise role of M. pneumoniae infection in the pathogenesis of different subtypes of ischaemic stroke, in all age groups, and in different ethnic populations.

Aged↗
PubMed1985

Improved graft patency in patients treated with platelet-inhibiting therapy after coronary bypass surgery.

One hundred forty-seven consecutive coronary bypass patients were enrolled in a randomized, double-blind, risk-stratified, placebo-controlled prospective trial evaluating the effect on graft patency of 325 mg tid aspirin (ASA) plus 75 mg tid dipyridamole (DP) or ASA alone. One hundred twenty-seven patients (399 total grafts) underwent surgery, initiation of drug therapy 67 +/- 27 (SD) hr postoperatively, five clinic visits, and repeat angiography at 1 year. A logistic regression statistical model was used to determine the effects of 28 different measured variables on graft patency and to adjust for these effects in determining the relationship between antiplatelet therapy and graft occlusion. No patient-specific variable contributed significantly to the prediction of occlusion in either the placebo or the treated group. Six graft-specific variables (arterial diameter, severity of stenosis, graft flow, reactive hyperemia, presence or absence of collaterals, and graft type) did contribute and were included in the model. Twenty-one percent of placebo-treated grafts became occluded. Compared with placebo, the relative risk of graft occlusion with ASA was 0.47 (p = .04); with ASA + DP, it was 0.50 (p = .04). This benefit was principally due to reduction of occlusion in the most common and presumably most important groups of grafts, those in which flow exceeded 40 ml/min, or supplying arteries having luminal diameters greater than 1.5 mm. Grafts lacking reactive hyperemia had a 32% occlusion frequency in placebo-treated patients; relative risk of their occlusion averaged 0.26 (p less than .01) with platelet-inhibiting therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2005

Falls in older people: effects of age and blurring vision on the dynamics of stepping.

PURPOSE: The risk of falling increases dramatically with age, and visual impairment is known to be an important risk factor. Therefore, it is highly pertinent to assess the effects of age and vision on the performance of everyday tasks linked to falling, such as stepping from one level to another. METHODS: Nine young (age, 26 +/- 4 years) and ten elderly (age, 72 +/- 5 years) subjects performed a stepping-up task of three different heights. Their stepping strategies with blurred and optimally corrected vision were compared. Center of mass (CM), center of pressure (CP) dynamics (in the mediolateral and anteroposterior directions), and foot clearance parameters were determined, and statistical regression modeling was applied. RESULTS: Elderly subjects spent 20% more time (P = 0.03) than young subjects during double support and they had reduced anteroposterior CM-CP divergence (P < 0.001) during double support and slower anteroposterior (P < 0.001) and mediolateral (P = 0.002) CM velocities during initiation of movement and single limb support. Blur caused similar adaptations, such as increased toe clearance, across both age groups, though mediolateral (ML) CM-CP divergence in elderly subjects was significantly more reduced than in young subjects (P < 0.001). CONCLUSIONS: Findings indicate, in general, that older subjects used a more cautious and controlled stepping strategy. However, the lack of significant age differences in toe clearance suggests this strategy was mainly aimed at reducing ML instability rather than increasing margins of safety regarding toe clearance.

Accidental Falls↗
PubMed1998

Two-year outcome in first-episode schizophrenia: predictive value of symptoms for quality of life.

OBJECTIVE: Many studies have validated the grouping of schizophrenic symptoms into three independent dimensions: negative, psychotic, and disorganized. Negative symptoms are considered to be an important prognostic indicator, but this clinical observation requires further empirical study, especially with respect to psychosocial functioning. When present at the onset of the first episode, negative symptoms suggest that the patient will develop significant psychosocial impairment. The predictive values of the psychotic and disorganized symptom dimensions, on the other hand, have been less certain. METHOD: In this study of 50 first-episode schizophrenic patients, who were mostly neuroleptic-naive at intake, the authors examined the relationship between the severity of these three symptom dimensions (measured by using the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms) at index hospitalization and quality of life at 2-year follow-up. RESULTS: Negative symptom severity was positively and significantly correlated with later occupational impairment, financial dependence on others, impaired relationships with friends, impaired ability to enjoy recreational activities, and global assessment of functioning. The magnitudes of correlation between the levels of psychotic symptoms or disorganized symptoms and 2-year quality of life measures were comparatively lower. Analyses using multivariate regression statistics also revealed similar findings. CONCLUSIONS: Severity of negative symptoms at index hospitalization may be a portent of poor outcome. In general, severity of psychotic or disorganized symptoms at intake does not appear to predict subsequent quality of life.

Adult↗