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Biomedical subjects

D L Riddle

Publications and source records attributed to D L Riddle.

At least 37 records · Page 2Linked to original sources
PubMed1998

Sensitivity to change of the Roland-Morris Back Pain Questionnaire: part 2.

BACKGROUND AND PURPOSE: One purpose of this study was to determine whether the Roland-Morris Back Pain Questionnaire (RMQ) could be used to detect clinically meaningful change in individual patients. The construct that served as the basis for this study was that RMQ change scores should be greater for patients meeting their treatment goals than for patients who did not meet their goals. The second purpose of the study was to determine whether sensitivity to change (STC) varies depending on the magnitude of the initial RMQ score. SUBJECTS AND METHODS: Of the 143 patients with low back pain who completed the study, 104 patients achieved their goals and 39 patients did not achieve their goals. Receiver operating characteristic (ROC) curve analysis and likelihood ratios were used to determine the RMQ change scores that best classify patients as having met or not met their goals. RESULTS: The area under the ROC curve for the entire RMQ scale was 0.68, while the curve areas for smaller RMQ intervals varied from 0.80 to 0.97. CONCLUSION AND DISCUSSION: The STC for the entire RMQ scale was poor for the construct examined in this study. The likelihood ratios for smaller RMQ intervals support the construct validity of the RMQ for assessing change in disability. Initial RMQ score magnitudes must be taken into account to improve the rate of making correct predictions about whether meaningful change in disability will occur following treatment.

Adolescent↗
PubMed1998

Examination and management of a patient with tarsal coalition.

The purpose of this case report is to illustrate how the literature can be used to guide clinical decisions related to a relatively uncommon pathological condition of the foot. This case report describes the approach used to examine and treat a 14-year-old boy referred by a physician for physical therapy with a diagnosis of peroneal spastic flatfoot (PSFF). Peroneal spastic flatfoot is a syndrome typically characterized by limited tarsal joint motion, a clonus response of the evertors, and a pes planus deformity. The patient reported having a limp for several years, but he said he was pain-free until he had an inversion injury of his foot. Because the physical therapists had not seen a patient with a diagnosis of PSFF, they reviewed the literature related to PSFF. They describe how their review enhanced their understanding of PSFF and how PSFF is related to the diagnosis of tarsal coalition, a pathological condition eventually identified in this child. Following 5 unsuccessful physical therapy sessions, they referred the patient to another physician who diagnosed a talocalcaneal coalition, a type of tarsal coalition.

Adolescent↗
PubMed1998

Classification and low back pain: a review of the literature and critical analysis of selected systems.

Classification systems for patients with low back pain have become more abundant in the literature since the mid-1980s. Some classification systems are designed to determine the most appropriate treatment, some are designed to aid in prognosis, and others are designed to identify pathology. Still other classification systems categorize patients into homogeneous groups based on selected variables. The purpose of this review is to describe and critically evaluate low back pain classification systems. Several classification systems were summarized and examined. Four classification systems that were judged to be the most commonly cited and most relevant to physical therapists were critiqued using a more thorough systematic approach. The analysis suggests that future research should address the usefulness of existing classification systems as well as the development of new classification systems designed using commonly accepted measurement principles.

Humans↗
PubMed1998

Use of generic versus region-specific functional status measures on patients with cervical spine disorders.

BACKGROUND AND PURPOSE: Few data exist to support the use of functional status measures on patients with disorders of the cervical spine. This study was designed to compare the construct validity and sensitivity to change of the Neck Disability Index (NDI) and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). SUBJECTS AND METHODS: Patients (N = 146) with a variety of disorders of the cervical spine completed the NDI and the SF-36 prior to treatment. Following discharge from treatment, 69 of these patients completed a second NDI and SF-36. RESULTS: There was evidence for the construct validity and sensitivity to change of the NDI and the physical and mental component scores of the SF-36. The ability of the NDI and SF-36 to detect change varied, depending on the construct tested. The SF-36 was superior in some instances, and the NDI was superior in other instances. The NDI appears to measure both mental and physical health-related factors. CONCLUSION AND DISCUSSION: There appears to be substantial overlap between the 2 measures. The use of both measures, therefore, is probably not necessary. [Riddle DL, Stratford PW. Use of generic versus region-specific functional measures on patients with cervical spine disorders.

Adult↗
PubMed1997

The shoulder pain and disability index: the construct validity and responsiveness of a region-specific disability measure.

BACKGROUND AND PURPOSE: The purposes of this study were (1) to assess the construct validity of the Shoulder Pain and Disability Index (SPADI) and (2) to determine whether the SPADI is more responsive than the Sickness Impact Profile (SIP), a generic health status measure. SUBJECTS: The sample consisted of 94 patients who were diagnosed with a shoulder problem and referred to six outpatient physical therapy clinics. METHODS: Clinically meaningful change was determined by use of an ordinal rating scale designed to determine whether the patient's shoulder function was improved, the same, or worse following treatment. Spearman rho correlations were calculated for the initial visit SPADI and SIP scores. The standardized response mean (SRM) was used to measure responsiveness for the patients who were judged to be improved. One-tailed paired t tests (alpha = .01) were used to determine whether differences existed among SRM values. RESULTS: Correlations between the SPADI and SIP scores ranged from r = .01 to r = .57. The SRM value was higher for the SPADI total score (SRM = 1.38) than for the SIP total score (SRM = 0.79). CONCLUSION AND DISCUSSION: Most correlations between SPADI and SIP scores provided support for the construct validity of the SPADI. The SPADI does not appear to strongly reflect occupational and recreational disability and is more responsive than the SIP.

Disability Evaluation↗
PubMed1996

Control of C. elegans larval development by neuronal expression of a TGF-beta homolog.

The Caenorhabditis elegans dauer larva is specialized for dispersal without growth and is formed under conditions of overcrowding and limited food. The daf-7 gene, required for transducing environmental cues that support continuous development with plentiful food, encodes a transforming growth factor-beta (TGF-beta) superfamily member. A daf-7 reporter construct is expressed in the ASI chemosensory neurons. Dauer-inducing pheromone inhibits daf-7 expression and promotes dauer formation, whereas food reactivates daf-7 expression and promotes recovery from the dauer state. When the food/pheromone ratio is high, the level of daf-7 mRNA peaks during the L1 larval stage, when commitment to non-dauer development is made.

Amino Acid Sequence↗
PubMed1996

Environmental induction and genetic control of surface antigen switching in the nematode Caenorhabditis elegans.

Nematodes can alter their surface coat protein compositions at the molts between developmental stages or in response to environmental changes; such surface alterations may enable parasitic nematodes to evade host immune defenses during the course of infection. Surface antigen switching mechanisms are presently unknown. In a genetic study of surface antigen switching, we have used a monoclonal antibody, M37, that recognizes a surface antigen on the first larval stage of the free-living nematode Caenorhabditis elegans. We demonstrate that wild-type C. elegans can be induced to display the M37 antigen on a later larval stage by altering the growth conditions. Mutations that result in nonconditional display of this antigen on all four larval stages fall into two classes. One class defines the new gene srf-6 II. The other mutations are in previously identified dauer-constitutive genes involved in transducing environmental signals that modulate formation of the dauer larva, a developmentally arrested dispersal stage. Although surface antigen switching is affected by some of the genes that control dauer formation, these two process can be blocked separately by specific mutations or induced separately by environmental factors. Based on these results, the mechanisms of nematode surface antigen switching can now be investigated directly.

Animals↗
PubMed1996

Longevity in Caenorhabditis elegans reduced by mating but not gamete production.

Theories of life-history evolution propose that trade-offs occur between fitness components, including longevity and maximal reproduction. In Drosophila, female lifespan is shortened by increased egg production, receipt of male accessory fluid and courting. Male lifespan is also reduced by courting and/or mating. Here we show that in the nematode Caenorhabditis elegans, mating with males reduces the lifespan of hermaphrodites by a mechanism independent of egg production or receipt of sperm. Conversely, males appear unaffected by mating. Thus, in C. elegans there is no apparent trade-off between longevity and increased egg or sperm production, but there is a substantial cost to hermaphrodites associated with copulation.

Animals↗
PubMed1996

Health status measures: strategies and analytic methods for assessing change scores.

Over the last 15 years, numerous self-report health status measures have appeared in the literature. An important parallel development has been the development of numerous strategies for assessing change in health status over time. The purpose of this article is to summarize and critique the more common design and analytic strategies for assessing the meaningfulness of change over time. Five commonly reported designs are presented, critiqued, and depicted using examples from the literature. Methods for analyzing results are reviewed and illustrated using two data sets. Insights into comparing competing health status measures are provided. In summary, the article suggests that some designs and analytic strategies are more adept than others at assessing change and that these methods should be considered when planning sensitivity-to-change studies.

Activities of Daily Living↗
PubMed1996

Intertester reliability of a modified version of McKenzie's lateral shift assessments obtained on patients with low back pain.

BACKGROUND AND PURPOSE: McKenzie described a two-step process for assessing patients with low back pain for a lateral shift. The purpose of this study was to determine whether reliable judgments about lateral shifts could be obtained. SUBJECTS: Forty-nine patients with low back pain were each examined separately by two randomly paired physical therapists. METHODS: Assessments of the presence and direction of lateral shifts (step 1) were obtained by use of a simple instrument. The relevance of the lateral shifts to the patients' pain complaints (step 1) also was assessed by use of the side-glide test sequence. RESULTS: Generalized kappa coefficients were calculated to determine reliability. The kappa value for the two-step process of lateral shift assessment was .16. The percentage of agreement was 47%. CONCLUSION AND DISCUSSION: Each step in this two-step process was examined separately for possible sources of error. The kappa value for determinations of the presence and direction of lateral shifts was .00, indicating very poor reliability. The kappa value for the determination of the presence of a positive side-glide test sequence was .74, indicating high reliability. The role of lateral shift assessment in the McKenzie system should be reconsidered, given the strong research evidence for poor reliability of determinations of the presence and direction of lateral shifts.

Adolescent↗
PubMed1996

Utilization of tests for Lyme disease antibody at a university hospital.

We performed a retrospective study on patients who had a positive screening antibody test result for antibody to Borrelia burgdorferi to determine the clinical indicators used by physicians to order this test. Eighty-two evaluable patients who were screen positive (indirect enzyme-linked immunosorbent assay) between August 1991 and March 1993 were included. Additional tests, isotype-specific capture immunoglobulin enzyme immunoassay and Western blot (immunoblot) analysis (immunoglobulin G), were performed on positive samples. Of 82 patients with a positive screening test result, 54 (66%) had no serologic evidence of Lyme disease on the basis of additional testing (positive predictive value, 34%). Only 28 of 82 patients (34%) had clinical indicators suggestive of Lyme disease. Antibody screening tests may provide misleading information if they are not accompanied by more specific assays. Inappropriate testing of patients without indications of Lyme disease is frequently performed, and the ordering practices of physicians should be reassessed.

Antibodies, Bacterial↗
PubMed1995

Mutations affecting the chemosensory neurons of Caenorhabditis elegans.

We have identified and characterized 95 mutations that reduce or abolish dye filling of amphid and phasmid neurons and that have little effect on viability, fertility or movement. Twenty-seven mutations occurred spontaneously in strains with a high frequency of transposon insertion. Sixty-eight were isolated after treatment with EMS. All of the mutations result in defects in one or more chemosensory responses, such as chemotaxis to ammonium chloride or formation of dauer larvae under conditions of starvation and overcrowding. Seventy-five of the mutations are alleles of 12 previously defined genes, mutations which were previously shown to lead to defects in amphid ultrastructure. We have assigned 20 mutations to 13 new genes, called dyf-1 through dyf-13. We expect that the genes represented by dye-filing defective mutants are important for the differentiation of amphid and phasmid chemosensilla.

Animals↗
PubMed1995

Genes that regulate both development and longevity in Caenorhabditis elegans.

The nematode Caenorhabditis elegans responds to conditions of overcrowding and limited food by arresting development as a dauer larva. Genetic analysis of mutations that alter dauer larva formation (daf mutations) is presented along with an updated genetic pathway for dauer vs. nondauer development. Mutations in the daf-2 and daf-23 genes double adult life span, whereas mutations in four other dauer-constitutive genes positioned in a separate branch of this pathway (daf-1, daf-4, daf-7 and daf-8) do not. The increased life spans are suppressed completely by a daf-16 mutation and partially in a daf-2; daf-18 double mutant. A genetic pathway for determination of adult life span is presented based on the same strains and growth conditions used to characterize Daf phenotypes. Both dauer larva formation and adult life span are affected in daf-2; daf-12 double mutants in an allele-specific manner. Mutations in daf-12 do not extend adult life span, but certain combinations of daf-2 and daf-12 mutant alleles nearly quadruple it. This synergistic effect, which does not equivalently extend the fertile period, is the largest genetic extension of life span yet observed in a metazoan.

Animals↗
PubMed1995

Blocking antibody assay for confirmation of urogenital Chlamydia infection.

We evaluated the Syva MicroTrak Chlamydia Blocking Antibody Assay as a confirmatory assay for the detection of Chlamydia trachomatis in urogenital specimens. During a 5-month period, 109 positives were obtained (4.9%) by the MicroTrak II Enzyme Immunoassay as implemented with the Syva XL automated enzyme immunoassay instrument. Of 98 evaluable samples, 92 (93.9%) were confirmed as positive by the blocking assay, and 3 blocking-negative samples had organisms detected by direct fluorescent-antibody analysis (blocking sensitivity, 96.8%). We found that direct fluorescent-antibody analysis of samples with a specimen-to-cutoff absorbance ratio of < or = 2.0 was a reasonable confirmation alternative and was more cost-effective than the blocking assay.

Adult↗
PubMed1995

Intertester reliability of measurements obtained with the KT-1000 on patients with reconstructed anterior cruciate ligaments.

Clinicians frequently measure anterior tibial displacement on patients following surgical reconstruction for a torn anterior cruciate ligament (ACL). Little is known about the reliability of measurements of anterior tibial displacement obtained on patients following an ACL reconstruction. The purpose of this study was to describe the degree of error associated with repeated measurements of anterior tibial displacement on patients with reconstructed ACLs. Random pairs of physical therapists used the KT-1000 to measure the anterior tibial displacement of 30 subjects. Each pair of examiners took measurements according to the manufacturer's instructions. Examiners took three sets of measurements while applying 6.8, 9.1, and 13.6 kg (15, 20, and 30 lbs) of force to the handle of the KT-1000. Intraclass correlation coefficients (ICC 2,1) and the standard error of the difference (SED) were calculated to describe the intertester reliability of the mean of three measurements of anterior tibial displacement at each force level and of the individual measurements at each force level. The SED was then multiplied by 2 to provide a 95% confidence estimate of the magnitude of error present with KT-1000 measurements. The SED estimates the magnitude of change in anterior tibial displacement necessary to infer that a real change in anterior tibial displacement has occurred. Clinicians can be 95% confident that changes in anterior tibial displacement of greater than 5 mm (+/- 2 SED) during KT-1000 tests at 6.8, 9.1, or 13.6 kg (15, 20, or 30 lbs) of force indicate that a true change in anterior tibial displacement has occurred.

Adult↗
PubMed1994

Identification of type I receptors for osteogenic protein-1 and bone morphogenetic protein-4.

Bone morphogenetic proteins (BMPs) are multifunctional proteins, structurally related to transforming growth factor-beta (TGF-beta) and activin. TGF-beta and activin exert their effects by forming heteromeric complexes of type I and type II serine/threonine kinase receptors. We have previously identified a series of type I serine/threonine kinase receptors, termed activin receptor-like kinase (ALK)-1 to -6. ALK-5 is a TGF-beta type I receptor, whereas ALK-2 and ALK-4 are activin type I receptors. Here we investigated the binding of proteins in the BMP family to ALKs. In transfected COS cells, the binding of osteogenic protein (OP)-1 and BMP-4 to certain ALKs was observed in the absence of type II receptors, and their binding was increased after co-transfection of a BMP type II receptor from Caenorhabditis elegans, DAF-4. OP-1 bound to ALK-2 and ALK-6 efficiently, and to ALK-3 less efficiently, whereas BMP-4 bound to ALK-3 and ALK-6 efficiently. Similarly, OP-1 bound to ALK-2, ALK-3, and/or ALK-6 in various nontransfected cell lines, although the binding profiles were different between different cell types. BMP-4 bound to ALK-3 in MC3T3-E1 osteoblasts and human foreskin fibroblasts. These results suggest that ALK-3 and ALK-6 are type I receptors for OP-1 and BMP-4; in addition, ALK-2 is a type I receptor shared by activin and OP-1, but not by BMP-4.

Activin Receptors↗
PubMed1994

Clinical comparison of the Baxter MicroScan Yeast Identification Panel and the Vitek Yeast Biochemical Card.

To determine the reliability of the Baxter MicroScan Yeast Identification Panel, processed by the Walkaway-96, and the Vitek Yeast Biochemical Card, 150 clinical yeast isolates (30 Candida albicans, 67 Candida species, not albicans, 26 Torulopsis glabrata, 13 Cryptococcus neoformans, 4 Saccharomyces cerevisiae, 6 Trichosporon beigelii, 3 Rhodotorula species, and 1 Geotrichum species) were tested on both systems. Results were compared with those obtained by the API 20C and the appearance of yeast cells on cornmeal Tween-80 agar. After inoculation of each system, results were available in 4 hours with MicroScan panels, 24-48 hours with Vitek cards, and 72 hours with the API 20C strips. On initial testing, 101 (67%) and 128 (85%) isolates, respectively, were correctly identified by MicroScan and Vitek. After repeat testing, the number of correctly identified isolates increased to 123 (82%) by MicroScan and to 142 (95%) by Vitek. Yeasts most commonly misidentified were Candida tropicalis, T glabrata, and Candida parapsilosis by MicroScan and C tropicalis and T glabrata by Vitek.

Mycology↗