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Biomedical subjects

P McClure

Publications and source records attributed to P McClure.

At least 19 recordsLinked to original sources
PubMed2000

A polymerase chain reaction method for the amplification of full-length envelope genes of HIV-1 from DNA samples containing single molecules of HIV-1 provirus.

Polymerase chain reaction (PCR) amplification of full-length envelope genes from the human immunodeficiency virus type 1 (HIV-1) directly from uncultured clinical samples is difficult. This paper describes a comparative assessment of the performance of three thermostable polymerases in an HIV-1 full-length envelope gene PCR. The PCR method utilising Expand HiFi polymerase was successful when using DNA samples extracted from a variety of sources including blood, semen and various tissues. This method generated high and specific yields of product from samples containing as little as one copy of HIV-1 proviral DNA. The resulting PCR products were suitable for a variety of downstream analytical methods including DNA sequence analysis.

Base Sequence↗
PubMed1999

Identification, mapping, and phylogenomic analysis of four new human members of the T-box gene family: EOMES, TBX6, TBX18, and TBX19.

Brachyury(T) is a mouse mutation, first described over 70 years ago, that causes defects in mesoderm formation. Recently several related genes, the T-box gene family, that encode a similar N-terminal DNA binding domain, the T-box, and that play critical roles in human embryonic development have been identified. It has been shown that human TBX5 and TBX3, if mutated, cause developmental disorders, Holt-Oram syndrome (OMIM 142900) and ulnar-mammary syndrome (OMIM 181450), respectively. We have identified four new human members of the T-box gene family, EOMES, TBX6, TBX18, and TBX19, and these genes have been mapped to different chromosomal regions by radiation hybrid mapping. The four T-box genes were classified into four different subfamilies and have also been subjected to phylogenomic analysis. Human EOMES maps at 3p21.3-p21.2. This Tbr1-subfamily gene is likely to play a significant role in early embryogenesis similar to that described for Xenopus eomesodermin. Human TBX6 maps at 16p12-q12. This Tbx6-subfamily gene is likely to participate in paraxial mesoderm formation and somitogenesis in human embryo. TBX18 is a novel member of the Tbx1 subfamily that maps at 6q14-q15. Two subgroups, TBX1/10 and TBX15/18 subgroups, could be distinguished within the Tbx1 subfamily. TBX19 is an orthologue of chick TbxT and maps at 1q23-q24. The genomic organization of TBX19 is highly similar to that of human T(Brachyury), another human member of the same subfamily.

Adult↗
PubMed1999

Health risk above the reference dose for multiple chemicals.

Recent work indicates that the regression of toxicity data viewed as categories of pathological staging is useful for exploring the likely health risk at doses above a Reference Dose (RfD), which is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. Toxic effects, which may include both quantal and continuous data, are classified into ordered categories of total toxic severity (e.g., none, mild, adverse, severe). These severity categories are regressed on explanatory variables, such as dose or exposure duration, to estimate the probability of observing an adverse or severe effect. In this paper, categorical regression has been expanded to compare the likely risks across multiple chemicals when exposures are above their RfDs. Existing health risk data for diazinon, disulfoton, S-ethyl dipropylthiocarbamate, fenamiphos, and lindane were analyzed. As expected, the estimated risks of adverse effects above the RfD varied among the chemicals. For example, at 10-fold above the RfD these risks were modeled to be 0.002, 0.0001, 0.0007, 0.002, and 0.02, respectively. The results and impacts of this analysis indicate that categorical regression is a useful screening tool to analyze risks above the RfD for specific chemicals and suggest its application in evaluating comparative risks where multiple chemical exposures exist.

Animals↗
PubMed1999

Stretching and strengthening exercises: their effect on three-dimensional scapular kinematics.

OBJECTIVE: To quantitatively evaluate the effects of commonly used shoulder exercises on shoulder kinematics and resting posture. STUDY DESIGN: A repeated-measures design was used with measurements performed before and after a 6-week exercise program. METHOD: Twenty asymptomatic subjects with forward shoulder posture were recruited. Stretching exercises for the pectoral muscles and resisted strengthening exercises for the scapular retractors and elevators and the glenohumeral abductors and external rotators were performed three times per week for 6 weeks. A three-dimensional electromechanical digitizer was used to measure thoracic inclination and scapular orientation and position. These measurements were taken with the arm (1) at the side, (2) abducted to 90 degrees, and (3) at maximal abduction. The isometric force of glenohumeral external and internal rotation and horizontal abduction and adduction were measured with a hand-held dynamometer. All subjects were tested before and after the 6-week exercise program. Hotelling's T2 and paired t tests were used for data analysis. RESULTS: The strength of horizontal abduction and internal and external rotation increased after exercise (p < .01). The anterior inclination of the thoracic spine decreased, and the glenohumeral contribution to arm elevation increased (p < .01). Resting scapular posture did not change. As the arm was abducted to 90 degrees, the scapula showed less upward rotation and less superior translation after the exercise program (p < .01). CONCLUSION: The exercise program improved muscle strength, produced a more erect upper trunk posture, increased scapular stability, and altered scapulohumeral rhythm.

Adult↗
PubMed1999

Thoracic position effect on shoulder range of motion, strength, and three-dimensional scapular kinematics.

OBJECTIVES: To determine the effect of thoracic posture on scapular movement patterns, active range of motion (ROM) in scapular plane abduction, and isometric scapular plane abduction muscle force. STUDY DESIGN AND METHOD: Repeated measures design. There were 34 healthy subjects (mean age, 30.2 yrs). Each subject was positioned and stabilized while sitting in both erect and slouched trunk postures. In each sitting posture a three-dimensional electromechanical digitizer was used to measure thoracic flexion and scapular position and orientation in three planes. Measurements were taken with the arm (1) at the side, (2) abducted to horizontal in the scapular plane, and (3) at maximum scapular plane abduction. In each posture, isometric abduction muscle force was measured with the arm at the side and abducted to horizontal in the scapular plane. RESULTS: In the slouched posture, the scapula was significantly more elevated in the interval between 0 to 90 degrees abduction. In the interval between 90 degrees and maximum abduction, the slouched posture resulted in significantly less scapular posterior tilting. There was significantly less active shoulder abduction ROM in the slouched posture (mean difference = 23.6 degrees +/- 10.7 degrees). Muscle force was not different between slouched and erect postures with the arm at the side, but with the arm horizontal muscle force was decreased 16.2% in the slouched position. CONCLUSION: Thoracic spine position significantly affects scapular kinematics during scapular plane abduction, and the slouched posture is associated with decreased muscle force.

Adult↗
PubMed1999

Comparison of 3-dimensional scapular position and orientation between subjects with and without shoulder impingement.

STUDY DESIGN: Nonrandomized 2 group post-test only. OBJECTIVE: To compare scapular position and orientation between subjects with and without impingement syndrome. BACKGROUND: Abnormal scapular motion is commonly believed to be a contributing factor to shoulder impingement syndrome. METHODS AND MEASURES: Twenty nonimpaired subjects with a mean age of 34.3 (+/- 7.5 years) and 17 patients with impingement syndrome with a mean age of 45.8 (+/- 11.0) participated. A 3-dimensional electromechanical digitizer was used to measure scapular position and orientation in 3 planes. Measurements were taken with the arm at the side, elevated in the scapular plane to horizontal, and at maximum elevation. One-way analysis of variance was used to compare nonimpaired subjects to the impingement group and the symptomatic and asymptomatic sides within the impingement group. Five scapular kinematic variables were assessed at each arm position. Orientation was described by posterior tilting angle, upward rotation angle, and internal rotation angle. Position was described by medial-lateral position and superior-inferior position and determined by the distance from the scapula centroid to the seventh cervical vertebra (C7). RESULTS: During scapular plane elevation of the arm, the scapula showed a general pattern of increasing posterior-tilt angle, increasing upward-rotation angle, and decreasing internal-rotation angle in both impingement and nonimpaired groups. Also, the scapula moved to a more superior position and a slightly more medial position with increasing arm elevation. Compared to nonimpaired subjects (34.6 degrees +/- 9.7), those with impingement demonstrated a significantly lower posterior tilting angle of the scapula in the sagittal plane (25.1 degrees +/- 9.1). Subjects with impingement also demonstrated higher superior-inferior scapular position with maximal arm elevation (5.2 cm +/- 1.6 below the first thoracic vertebrae) compared to nonimpaired subjects (7.5 cm +/- 1.5). CONCLUSIONS: These results suggest that altered scapular kinematics may be an important aspect of the impingement syndrome.

Adult↗
PubMed1998

Three-dimensional flexibility characteristics of the human cervical spine in vivo.

STUDY DESIGN: A test-retest design to establish the reliability of a new system capable of quantifying the load-displacement characteristics of the cervical spine. The study was primarily descriptive, but the design allowed comparisons between men and women as well as within-group comparisons among different cervical motions. OBJECTIVES: To determine the flexibility of the entire cervical spine in vivo and to establish the reliability of a new system developed for this purpose. SUMMARY OF BACKGROUND DATA: The flexibility of the cervical spine has been studied primarily in vitro by applying loads to isolated osteoligamentous segments. Quantification of the mechanical characteristics of the cervical spine in vivo may provide insights to the effects of pathology and treatment interventions. In vivo flexibility measurements differ from those in vitro in that they involve the entire cervical spine composite, including the muscles, rather than isolated segments. METHODS: Our method uses a 6 degrees of freedom mechanical linkage system aligned anatomically according to Grood and Suntay parameters and allows manual application of torque around each axis. We determined the range of motion and flexibility of the cervical spine in a sample of young, healthy subjects (n = 20) for flexion, right lateral bending, and bilateral axial rotation. RESULTS: Acceptable test-retest reliability were found for range of motion and flexibility measurements performed several days apart. The general shape of the torque-angle curves was nonlinear and biphasic. An early, very flexible portion of the curve was defined as the neutral zone, and the less flexible, end portion of the curve was defined as the elastic zone. We found that men were less flexible than women and that men could tolerate greater amounts of passively applied torques. All subjects showed significantly greater flexibility and less torque tolerance in axial rotation compared with those values in flexion and lateral bending. Possible anatomic explanations for these differences include the effect of muscle alignment and flexibility differences between synovial and fibrocartilaginous articulations. CONCLUSIONS: This study provides data regarding the in vivo flexibility of the human neck in young, healthy subjects and forms the basis for comparison in future studies that assess the effects of pathology and treatment. Men have lower flexibility than women, and axial rotation flexibility is significantly greater than that in lateral bending and flexion.

Adult↗
PubMed1996

The influence of different sitting positions on cervical and lumbar posture.

STUDY DESIGN: This study used a repeated measures design to assess the effects of multiple sitting postures on various spinal angles. All subjects were tested in slouched, erect, forward inclined, and comfortable postures. OBJECTIVES: The purposes of this study were to evaluate the changes in head, cervical, lumbar, and pelvic postures in different sitting positions and also to determine if there is a relation between lumbar posture and cervical posture during sitting. SUMMARY OF BACKGROUND DATA: Clinicians commonly assert that head and neck position is strongly influenced by lumbar and pelvic position. A biomechanical model was developed that allowed detailed, quantitative description of head, neck, lumbar, and pelvic postures. This model enabled a distinction to be made between upper and lower cervical motions. METHODS: Various spinal angles were measured in 30 healthy subjects in four sitting positions using a three-dimensional digitizing system. Reliability of the measurement procedure was determined using an intraclass correlation coefficient and the values for most angles was above 0.8. RESULTS: With the exception of head orientation, analysis of variance revealed significant differences in spinal angles between different sitting positions. Head orientation appeared to be maintained by compensatory adjustments in both the upper and lower cervical spine and changes in lumbar posture were associated with compensatory changes in overall cervical position. As the lumbar spine moved toward extension, the cervical spine flexed and as the lumbar spine flexed the cervical spine extended. However, there was variation among subjects as to whether cervical spine adjustments occurred primarily in the upper or lower cervical region. CONCLUSIONS: Different sitting postures clearly resulted in changes in cervical spine position. Lumbar and pelvic position should be considered when control of cervical posture is desired.

Adult↗
PubMed1995

Evaluating a comprehensive outpatient clinical information system: a case study and model for system evaluation.

Decisions about information system implementation are often justified through a cost-benefit analysis. The ability to improve efficiency and outcomes while decreasing costs through information systems--by allowing for multiple and instant simultaneous access to information, through data monitoring and altering, through automation of protocols, and by collecting information for population-based health care as opposed to individual illness-care--are all potential benefits of a comprehensive clinical information system. Measuring the quantitative impact of these system improvements, however, is difficult. Doing a complete cost-benefit analysis of a comprehensive clinical information system is unrealistic due to the many assumptions necessary and the multiple confounding factors that are involved. In our Clinical Information Systems deployment in Kaiser Permanente, Northwest Region, we have elected not to do a detailed cost-benefit analysis. Instead, we have done an evaluation, based on success criteria, of a pilot implementation of a vendor-supplied system. This evaluation is based on clinician acceptance, system usage, technical factors, and quantitative effects on physician productivity. We also considered qualitative factors such as relationship with and responsiveness of the system vendor. We are moving ahead to regionalize this clinical information system based on such an evaluation of our pilot project. This paper outlines the approach that we have taken in evaluating our implementation of this system. It may provide some guidance for organizations on how to make a decision about whether or not to regionalize a clinical information system based on the evaluation of a pilot-site implementation.

Ambulatory Care Information Systems↗
PubMed1995

Integrated clinical database in a health maintenance organization.

This paper describes the development and implementation of the first phase of a comprehensive clinical information system in the Kaiser Permanente Northwest Region. This system integrates information from disparate departmental systems into a single clinical database. By using periodic batch downloads of patient data from departmental systems into the clinical database, rather than requiring real-time updates, we have been able to implement this system with relative ease and speed. It contains patient demographics, lab, outpatient pharmacy, radiology, pathology, dictated consults, admission histories and physicals, discharge summaries, and other dictated reports for over 380,000 Health Plan Members. The system is fast, intuitive, reliable, and user-friendly. In March 1994, there were approximately 1,600 active users. These individuals accounted for approximately 410,000 transactions in the month, with an average daily transaction volume of 11,450. Quantifiable cost-savings, in terms of decreased chart pulls and decreased phone calls for information, have offset the cost of development and implementation to some extent. Less quantifiable improvements in the quality of care and the associated cost-savings may eclipse the quantifiable benefits. This system lays the foundation for our clinical information system efforts.

Health Maintenance Organizations↗
PubMed1984

Intracranial hemorrhage in hemophilic children. CT follow-up.

In a follow-up examination of intracranial hemorrhage in hemophilic children, 9 patients were examined clinically and with CT. The results stress the value of CT in the evaluation of hemophilic children with possible head trauma. The extent of the structural brain damage after intracranial hemorrhage in most cases is more marked than clinically expected, and such damage may also be present in patients who clinically have no neurologic sequelae.

Brain↗
PubMed1982

Hodgkin's disease in children: treatment results with MOPP and low-dose, extended-field irradiation.

Combined therapy with MOPP and extended-field irradiation for all children with Hodgkin's disease (except those with favorable clinical stage [CS] 1) was effective in disease control. Overall 5-year survival and relapse-free survival rates were 92% and 82%, respectively. Only one of 27 CS 2 and 3 patients has relapsed (median followup, 4.3 years). Two patients in complete remission died of viral infection. The cost-benefit ratio for such treatment remains to be determined. Morbidity was decreased by the omission of staging laparotomy with splenectomy and by reduction in radiation dose and to a lesser extent volume, but it was increased by the addition of MOPP. In such combined treatment, the smallest number of cycles of MOPP, the lowest radiation dose, and the smallest radiation volume that may be used without loss of treatment effectiveness remain to be determined.

Adolescent↗
PubMed1979

Hodgkin's disease in children: treatment with low dose radiation and MOPP without staging laparotomy: a preliminary report.

Twenty-seven children with previously untreated Hodgkin's disease (CS I-2, II-13, III-3, IV-9) were given three cycles of MOPP to induce a remission which was consolidated with extended field radiation (2000--3500 rad) and three cycles of MOPP. Surgical staging was discontinued. Twenty-five of 27 children have not relapsed (range 15+--64+ months; median 39+ months); two children have died, one of uncontrolled Hodgkin's disease and one of acute infection while in complete remission. Actuarial 3 and 5 year survival rates and relapse-free rates are 91%. The merits of this treatment approach are discussed.

Antineoplastic Agents↗
PubMed1975

Idiopathic thrombocytopenic purpura in two children with Graves disease.

Chronic idiopathic thrombocytopenic purpura (ITP) and hyperthyroidism coexisted in two children. In one, hyperthyroidism developed nine years after the onset of purpura. In the other, the two diseases appeared concomitantly. It is important to distinguish the thrombocytopenia due to ITP from that due to antithyroid drugs.

Azathioprine↗
PubMed1975

Storage and retrieval properties of dual codes for pictures and words in recognition memory.

Storage and retrieval properties of pictures and words were studied within a recognition memory paradigm. Storage was manipulated by instructing subjects either to image or to verbalize to both picture and word stimuli during the study sequence. Retrieval was manipulated by representing a proportion of the old picture and word items in their opposite form during the recognition test (i.e., some old pictures were tested with their corresponding words and vice versa). Recognition performance for pictures was identical under the two instructional conditions, whereas recognition performance for words was markedly superior under the imagery instruction condition. It was suggested that subjects may engage in dual coding of simple pictures naturally, regardless of instructions, whereas dual coding of words may occur only under imagery instructions. The form of the test item had no effect on recognition performance for either type of stimulus and under either instructional condition. However, change of form of the test item markedly reduced item-by-item correlations between the two instructional conditions. It is tentatively proposed that retrieval is required in recognition, but that the effect of a form change is simply to make the retrieval process less consistent, not less efficient.

Concept Formation↗
PubMedDate not supplied

The degenerative cervical spine: pathogenesis and rehabilitation concepts.

The degenerative process associated with spondylosis in the cervical spine has been reviewed. The two compressive syndromes commonly associated with spondylosis, radiculopathy and myelopathy, are briefly reviewed. Except for more severe, multilevel degenerative changes producing neurologic compromise, correlation between degenerative changes and patient symptoms or functional limitations is generally poor. A conceptual scheme for guiding rehabilitation of mechanical neck pain, based on irritability level and the effects of mechanical stress on symptoms, is proposed. Further research is required to test the reliability and validity of categorization schemes like the one proposed. Such schemes based on history and effects of mechanical stresses, rather than solely on degenerative radiographic findings, are necessary to classify patients in meaningful ways that help guide specific rehabilitation strategies and tactics. When meaningful classification schemes exist, treatments matched with specific categories of dysfunction can be tested for effectiveness.

Cervical Vertebrae↗