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Biomedical subjects

J Pugh

Publications and source records attributed to J Pugh.

At least 37 records · Page 2Linked to original sources
PubMed1989

Characterization of the major duck hepatitis B virus core particle protein.

The amino acid composition of the major duck hepatitis B virus (DHBV) core particle proteins was determined. The results of this analysis indicated that cores are composed of a single major protein that initiates translation from the second available AUG in the DHBV core gene. Proteins isolated from core particles purified from the cytoplasm of DHBV-infected duck hepatocytes exhibited heterogeneity in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, independent of the stage of viral DNA maturation. Incubation of native cores with alkaline phosphatase removed this heterogeneity, indicating that phosphorylation of external amino acids was responsible. Core protein isolated from mature DHBV purified from serum of infected animals did not display heterogeneity, suggesting a possible role for dephosphorylation in virus maturation.

Alkaline Phosphatase↗
PubMed1988

Nebuhaler or nebulizer for high dose bronchodilator therapy in chronic bronchitis: a comparison.

We have compared the clinical efficacy of high dose terbutaline sulphate (10 mg four times daily) delivered by either a Nebuhaler or jet nebulizer in 13 patients with chronic bronchitis in a 2-week, open, crossover study. Both treatment regimens improved run-in symptom scores but no significant changes were recorded in peak flow and spirometry. Side-effects were more common with the Nebuhaler and more patients preferred the nebulizer. However, the Nebuhaler is an alternative therapeutic option for delivery of high doses of bronchodilators in patients with chronic bronchitis.

Aged↗
PubMed1987

Healing of experimentally produced lesions in articular cartilage following chondrocyte transplantation.

Articular cartilage is known to have limited ability to heal once injured, and attempts to heal lesions in cartilage have yielded equivocal results. The following experiments were performed to investigate healing in cartilage transplantation of chondrocytes grown in vitro. The knee joint of the New Zealand White rabbit was used as the experimental model. An initial baseline study was made to determine the intrinsic capability of cartilage for healing defects that do not fracture the subchondral plate. A second experiment examined the effects of autologous in vitro grown chondrocytes on the healing rates of these defects. The results were evaluated by qualitative and quantitative light microscopy. In control defects not grafted with chondrocytes, 6 weeks after the initial defect was created, there was little repair. Macroscopic and histological findings were consistent with an osteoarthritic pathology such as synovitis and "cell nests." Macroscopic results from grafted specimens displayed a marked decrease in synovitis and other degenerative changes. Defects which had received transplants had a significant amount of cartilage reconstituted (82%) compared to ungrafted controls (18%). Controls showed a healing rate comparable to that obtained in the initial baseline study.

Animals↗
PubMed1987

Alterations in primary and coupled neck motions after facetectomy.

Normal neck motion is a complicated phenomenon. A primary motion results from an applied force or torque. Secondary coupled motions also result as a consequence of the primary motion. These resulting coupled motions were measured in isolated cervical motion segments using three-dimensional videophotogrammetry with a coordinate system fixed in space. A cross coupling algorithm provided error correction and conversion from local to true cartesian coordinates. The data were analyzed by computer, and the true coupled motions resulting from any applied force were obtained. A second group of specimens was facetectomized, and the experiments were repeated. After facetectomy, a moment about the anteroposterior axis resulted in marked reduction in lateral displacement, decrease in vertical displacement, and decrease in rotation about the vertical axis. Results were significant at P less than 0.01 and represent a significant decrease in coupled motions resulting from lateral bending. At P less than 0.05, a laterally applied force causes less lateral displacement and lateral flexion, but more longitudinal displacement. Flexion and extension movements are not significantly altered after facetectomy.

Biomechanical Phenomena↗
PubMed1987

Do upper-body and centralized adiposity measure different aspects of regional body-fat distribution? Relationship to non-insulin-dependent diabetes mellitus, lipids, and lipoproteins.

Both central and upper-body adiposity are associated with high rates of type II non-insulin-dependent diabetes mellitus (NIDDM), high triglyceride levels, and low high-density lipoprotein (HDL) cholesterol levels. Previous data have also suggested that central and upper-body adiposity are relatively uncorrelated and hence may measure different aspects of regional body fat distribution. We assessed body mass index (BMI), the ratio of subscapular-to-triceps skinfold (STR), the ratio of waist-to-hip circumference (WHR), lipids, lipoproteins, and glucose tolerance in 738 Mexican Americans (ages 25-64 yr), who participated in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. NIDDM was diagnosed according to National Diabetes Data Group criteria. In general, STR and WHR were associated with high NIDDM rates, low HDL cholesterol levels, and high triglyceride levels, although WHR was somewhat more predictive of these than STR. In females, BMI, WHR, and STR all made independent contributions to prediction of NIDDM and HDL cholesterol; in males, WHR and STR both made independent contributions to prediction of triglyceride levels. This suggests that both indices may measure different aspects of body-fat distribution. Investigators should consider measuring both of these indicators of body-fat distribution in studies of diabetes and other cardiovascular risk factors, although if only a single measure is feasible, WHR appears to be preferable.

Adipose Tissue↗
PubMed1986

Auditory biofeedback in spastic diplegia.

Using a simple auditory feedback device that produces a continuous buzzing signal on heel contact, we studied the effects of augmented auditory biofeedback on the gait of four spastic diplegic children. The purpose of the biofeedback was to attempt to increase dorsiflexion at heel strike without causing other compensatory changes at the knee and hip, which might lead to crouch gait. We measured velocity, stride length, and thigh, knee, and ankle angles at the heel strike, midswing, and toe-off phases of gait. Four subjects, aged 5-8 years, were given a standard gait training program, supplemented with biofeedback two times per week in a clinical setting and 1 h daily in a home program over an 8-week period. Three computer video gait analyses of the sagittal plane were conducted without biofeedback in the pre- and posttraining conditions and twice with biofeedback over the course of treatment. We performed linear regression analysis of joint angles at heel strike, midswing, and toe-off as a function of days into the study for each patient. Angle-angle diagrams for a test subject before, during, and after treatment indicate changes toward a normal gait pattern with biofeedback. The linear regression analysis showed a statistically significant (p less than 0.01) shift toward dorsiflexion at heel strike with repeated exposure to biofeedback. A compensatory crouch gait was not induced. The linear regression analyses for hip and knee angles were not statistically significant (p greater than 0.25), indicating a disassociation of movement among hip, knee, and ankle.

Acoustic Stimulation↗
PubMed1986

Upper body and centralized adiposity in Mexican Americans and non-Hispanic whites: relationship to body mass index and other behavioral and demographic variables.

Mexican Americans have a higher prevalence of NIDDM, more overall obesity and more centralized adiposity than non-Hispanic whites, but have thus far not been characterized as to whether they have greater upper body adiposity. Waist-to-hip circumferences (WHR, a measure of upper body adiposity) and subscapular-to-triceps skinfold ratios (centrality index, a measure of centralized adiposity) were determined in 725 Mexican Americans and 226 non-Hispanic whites as part of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. Mexican American females had higher centrality indices and WHRs than non-Hispanic white females, even after adjustment for demographic (age, menopausal status) and behavioral variables (body mass index, parity, cigarette smoking, alcohol consumption, exercise, and oral contraceptive and estrogen use). Mexican American males had higher centrality indices than non-Hispanic white males, but differences in WHR disappeared after adjustment for overall adiposity (body mass index). Of the demographic and behavioral variables, only age and body mass index were consistently related to regional body fat distribution. The lack of an association between body fat distribution and behavioral variables suggests that genetic factors may play the principal role in determining body fat distribution. Surprisingly, the distributions of centrality index and WHR were relatively independent of one another suggesting that they may be used as distinct, independent predictors of metabolic diseases.

Adipose Tissue↗
PubMed1985

Cervical facetectomy and its effect on spine strength.

Fourteen cervical spine motion segments consisting of two adjacent vertebral bodies and their connecting ligaments were tested in shear. Five had intact facet joints, five had bilateral facetectomy of 50% or less, and four had bilateral 70% facetectomy. Three to 5 mm of root could be exposed in the specimens with 50% facetectomy, and 8 to 10 mm in those with 70% facetectomy. Anterior-posterior shear tests were run alternately in compression and distraction. Facetectomy was found to have no effect on compression and distraction stiffness. Failure in the 70% facetectomized specimens was due to fracture of the remaining joint at 159 lbs. In the specimens with 50% facetectomy, a fracture load could not be established since failure of the specimen mounting occurred at 208 lbs, as it did in two of the specimens without facetectomy that were tested to failure. The difference in bone fracture at 159 lbs and mounting failure at 208 lbs is significant at p less than 0.05. Bilateral resection of more than 50% of the facet joint significantly compromises the shear strength of a cervical spine motion segment.

Cervical Vertebrae↗
PubMed1984

The problem of evaluating in situ pinning of slipped capital femoral epiphysis: an experimental model and a review of 63 consecutive cases.

Over a 3-year follow-up period, 63 hips (in 49 patients) that were pinned as treatment for slipped capital femoral epiphysis were examined and evaluated. A 36.8% incidence of unsuspected pin penetration was discovered. Four types of experimental models representing different degrees of severity of slipped capital femoral epiphysis were designed and manufactured in the bioengineering laboratory. In situ pinning was performed on each model. An extensive series of controlled test films on the models indicated the difficulty of accurately determining the true position of the pins with conventional roentgenographic views. Subsequent fluoroscopic analysis revealed a verifiable correlation between the limited visualization of conventional X-ray analysis following the pinning of a slipped capital femoral epiphysis and unrecognized pin penetration.

Bone Nails↗
PubMed1984

A method of evaluating possible pin penetration in slipped capital femoral epiphysis using a cannulated internal fixation device.

A technique that utilizes a newly designed cannulated screw with injection of radiographic dye through the screw cannula provides a reliable and practical method for detection and avoidance of pin penetration when operating on slipped capital femoral epiphyses. Adoption of this method minimizes the possibility of poor results occurring as a consequence of internal fixation.

Bone Nails↗
PubMed1984

Comparison of the relative effects of aspirin, mefenamic acid, dihydrocodeine, dextropropoxyphene and paracetamol on visceral pain, respiratory rate and prostaglandin biosynthesis.

A comparison was made between the relative effects of aspirin, mefenamic acid, dihydrocodeine , dextropropoxyphene and paracetamol on visceral pain (chemically-inducing writhing), respiratory rate and prostaglandin (PG) biosynthesis (cyclo-oxygenase activity). A close correlation was found to exist between inhibition of PG biosynthesis and inhibition of visceral pain for mefenamic acid, aspirin and paracetamol. Analysis of the complete activity profiles derived from evaluation of the test parameters yielded the following rank order of overall ratios of their beneficial anti-writhing/anti-cyclo-oxygenase to respiratory depressive activities: (1) mefenamic acid, (2) aspirin, (3) dihydrocodeine , (4) dextropropoxyphene and paracetamol.

Acetaminophen↗
PubMed1983

Scoliosis and growth. An analysis of the literature.

A review of the literature discloses the buckling phenomenon as responsible for the initiation of lateral deformation and the progression of small curves in idiopathic scoliosis. From the point of view of parsimony, buckling explains how ligamentous laxity, increased interdiscal flexibility, muscular asymmetries, neurologic lesions, morphologic, anthropometric, and sexual differences would contribute to development of the deformity. Thus, a buckling theory seems to embody the fragmented character of present information about the etiology of idiopathic scoliosis.

Adolescent↗
PubMed1982

Osteomyelitis and neoplasia associated with use of the Jonas intramedullary splint in small animals.

In 11 cases (10 dogs, 1 cat) in which fractures were repaired with the Jonas intramedullary splint, osteomyelitis developed in 6 and tumors developed in 5. In each case, the tumor originated in close proximity to the splint, at the midshaft of the femur or radius. All implants had been in place for 6 months to 6 years in the case of tumors, and for 4 months to 6 years in the cases involving osteomyelitis. Corrosion was evident in all retrieved implants. The corrosion was attributed to fabrication of the devices with a corrosion-susceptible stainless steel, AISI type 304. The corrosion was believed to have been accelerated by stress effect due to differences in cold work of the sleeve and pin and the difference in composition between the sleeve and spring of the splint. It was concluded that fixation of fractures in small animals should not be performed with the Jonas intramedullary splint.

Animals↗
PubMed1982

Three-dimensional lordosimeter. A device for the nonradiographic assessment of spinal configuration.

A technique is presented for the nonradiographic assessment of spinal configuration. Its use in the assessment of scoliotic curvatures is discussed in the light of existing radiographic and nonradiographic techniques. The reproducibility of point-encoding measurements relative to a fixed standard is shown to be 98.8 percent. The correlation of pointencoded spinal angles with similar data taken from x-rays is significant at p less than 0.0005. The average standard deviation in the measurement of spinal angles of 10 successive trials on five test subjects is 3.55 degrees +/- 1.95 degrees.

Humans↗
PubMed1982

Biomechanics of pathologic fractures.

The successful treatment of a patient with a tumor involves an estimate of weakening due to the tumor and a consideration of the probability of gross fracture through that defect. Weakening due to an open section defect usually results in fracture. Holes produce a stress concentration that is of concern to the orthopedist in reconstituting such fractures. The reconstitution itself must be such that the postoperative possibility of refracture is minimized. Surface-structured intramedullary devices and polymethylmethacrylate offer conversion of open sections into closed sections and minimize the stress risers to allow significant uniaxial bending and torsional loads to be carried by the reconstituted bone, which is usually of inadequate quality to allow reconstitution with screws, plates, and cement. Treatment of a pathologic fracture often involves extensive bony resection, necessitating reconstitution for mechanical stability and reduction of limb shortening. Several combinations of polymethylmethacrylate bone cement and standard metallic devices are satisfactory for reconstitution. Those combinations that offer the maximum cement-metal interface interactions should be chosen and used with proper cement preparation and delivery.

Animals↗