Search PubMed⌕ Search

Biomedical subjects

J R Moore

Publications and source records attributed to J R Moore.

At least 19 recordsLinked to original sources
PubMed1997

Phosphorylation-dependent power output of transgenic flies: an integrated study.

We examine how the structure and function of indirect flight muscle (IFM) and the entire flight system of Drosophila melanogaster are affected by phosphorylation of the myosin regulatory light chain (MLC2). This integrated study uses site-directed mutagenesis to examine the relationship between removal of the myosin light chain kinase (MLCK) phosphorylation site, in vivo function of the flight system (flight tests, wing kinematics, metabolism, power output), isolated IFM fiber mechanics, MLC2 isoform pattern, and sarcomeric ultrastructure. The MLC2 mutants exhibit graded impairment of flight ability that correlates with a reduction in both IFM and flight system power output and a reduction in the constitutive level of MLC2 phosphorylation. The MLC2 mutants have wild-type IFM sarcomere and cross-bridge structures, ruling out obvious changes in the ultrastructure as the cause of the reduced performance. We describe a viscoelastic model of cross-bridge dynamics based on sinusoidal length perturbation analysis (Nyquist plots) of skinned IFM fibers. The sinusoidal analysis suggests the high power output of Drosophila IFM required for flight results from a phosphorylation-dependent recruitment of power-generating cross-bridges rather than a change in kinetics of the power generating step. The reduction in cross-bridge number appears to affect the way mutant flies generate flight forces of sufficient magnitude to keep them airborne. In two MLC2 mutant strains that exhibit a reduced IFM power output, flies appear to compensate by lowering wingbeat frequency and by elevating wingstroke amplitude (and presumably muscle strain). This behavioral alteration is not seen in another mutant strain in which the power output and estimated number of recruited cross-bridges is similar to that of wild type.

Animals↗
PubMed1997

Nasal cartilage grafts: more than a decade of experience.

From 1985 to 1995, a total of 311 patients underwent nasoplasties. During this time period, the number of patients receiving grafts increased from 94 percent in 1985-1989 to 100 percent in 1993-1995. The donor grafts averaged 72 percent nasal cartilage, 10 percent conchal cartilage, 9 percent fascia, and 9 percent rib allograft. Graft recipient sites averaged 41 percent in the tip, 31 percent in the dorsum, 17 percent in the columella, and 3 percent in the region of the lower lateral cartilage; 8 percent were spreader grafts. During this time frame, tip grafting increased from 34 percent in 1985-1989 to 54 percent in 1993-1995. Reoperation for complications decreased from 17 percent in 1985-1989 to 2 percent in 1993-1995. During the time span examined, the use of rib allografts declined, the use of autologous cartilage increased, the use of onlay tip grafts increased, and the incidence of reoperations declined. Early in the series, 80 percent of the malplaced tips were shield type grafts. With the use of the onlay tip graft, the complication of a malpositioned tip has been substantially diminished. The increased use of crushed cartilage has resulted in improvement in results and patient satisfaction, as it serves to camouflage slight irregularities in the tip and dorsum of the nose.

Bone Transplantation↗
PubMed1996

Correction for distortion of echo-planar images used to calculate the apparent diffusion coefficient.

An algorithm for correcting the distortions that occur in diffusion-weighted echo-planar images due to the strong diffusion-sensitizing gradients is presented. The dominant distortions may be considered to be only changes of scale coupled with a shear and linear translation in the phase-encoding direction. It is then possible to correct for them by using an algorithm in which each line of the image in the phase-encoding direction is considered in turn, with only one parameter (the scale) to be found by searching.

Algorithms↗
PubMed1996

Endoscopic transaxillary submuscular augmentation mammaplasty with textured saline breast implants.

The utility of the endoscope was realized in a retrospective analysis of 92 consecutive patients undergoing augmentation mammaplasty with saline-filled textured implants. The transaxillary submuscular approach was used. All patients received preoperative antibiotics and instillation of methylprednisolone into the saline fill, with inflation to manufacturer-recommended levels. complications included seven implant deflations (3.8%), eight implant malpositions (4.3%), and one capsular contracture (0.6%). Of the eight malpositions, six were corrected using the endoscopic technique without removal of the implant and with early manipulation of the implant within the pocket. We conclude that endoscopic control in augmentation mammaplasty is beneficial in secondary operative procedures and we speculate that the endoscope will lessen the rate of implant malposition observed in this study.

Endoscopy↗
PubMed1995

Solid state phosphorus-31 magnetic resonance imaging of bone mineral.

Chemically selective solid state phosphorus-31 nuclear magnetic resonance (NMR) imaging of the mineral phase of bone and synthetic calcium phosphate models for bone mineral is demonstrated with microscopy-scale (about 5 mm field of view) apparatus at 6.0 T magnetic field strength. Pixel-by-pixel linear combination of image data from multiple radio frequency (RF) pulse sequences, chosen to develop contrast between chemical constituents of interest in the mineral, generates derived images showing the distribution of individual constituents. The technique combines the noninvasive character of magnetic resonance imaging (MRI) with the ability of solid state NMR spectroscopy to characterize subtle chemical variations in bone mineral, as well as to measure the amount of mineral. These methods are, in principle, extensible to larger dimensional scales suitable for live animal subjects or human limbs.

Animals↗
PubMed1995

Infant sleep position and the sudden infant death syndrome. A survey of pediatric recommendations.

A questionnaire survey was conducted to assess the impact of the April 1992 American Academy of Pediatrics Task Force Statement, "Infant Positioning and SIDS," on the routine advice provided by pediatricians in Minnesota to families with newborn infants regarding sleep practices, including sleep position. There was a trend toward more discussion between all pediatric practice groups and families regarding infant sleep practices following the AAP Sleep Position Statement (P < 0.001-0.003). Prone sleep recommendations ranged from 9.2% for newborn infants to 21.4% for infants 6 months of age. Recommendations for the supine or lateral sleep positions predominated at all infant ages. Pediatricians in private practice were more likely to identify the AAP Statement as establishing a medicolegal standard (P < 0.05). We conclude that the 1992 AAP Statement has had a significant impact on the routine advice provided to families regarding infant sleep practices, including infant sleep position.

Humans↗
PubMed1995

Elderly residents: perceptions of nurses' comforting touch.

1. Elderly nursing home residents often feel unwanted or unloved because of a lack of physical contact with others or their caregivers' inability to communicate love and belonging. 2. In a study of 25 elderly nursing home residents, it was found that those who were subjected to comforting touch by their nurses perceived an increased feeling of affection and immediacy. 3. The conscious and intentional use of comforting touch by nurses and caregivers to elderly nursing home residents should be encouraged because of its beneficial effect of conveying love and belonging.

Aged↗
PubMed1994

Steps in the evolution of extracranial time-of-flight MR angiography.

Magnetic resonance (MR) angiography is not a set technique but is constantly evolving. This article illustrates changes in image quality in extracranial MR angiography that have been achieved over the past few years by the introduction of several technical developments. Images from patients examined at intervals of 12 months or more demonstrate the improvements in image quality that have resulted from these technical changes. These include bandwidth optimization for operation at 1.0 T and changes in flip angle section thickness, repetition time, and echo time. Improved image quality was assessed with objective measures of contrast-to-noise and signal-to-noise ratios. The cases illustrated show the use of MR angiography to evaluate the portal or systemic veins in patients being evaluated for liver transplantation, venous occlusion, and other venous disease. Improvements in image quality are subjectively apparent and emphasize the importance of keeping pace with technical improvements in MR angiography.

Humans↗
PubMed1994

Antioxidant status of dairy cows supplemented prepartum with vitamin E and selenium.

Possible relationships among dietary antioxidants, oxidative status, and placental retention were investigated in periparturient dairy cows. During 6 wk prepartum, 16 cows each were given daily by capsule 1000 IU of vitamin E, 3 mg of Se, both vitamin E and Se, or neither (control). alpha-Tocopherol in serum and fast-acting antioxidants in plasma increased, but, in red blood cells, thiobarbituric acid-reactive substances decreased during the last 6 wk before parturition in cows given vitamin E. These measurements were unaffected by supplementation of Se. Cows that had retained placenta > or = 12 h had lower fast-acting antioxidants in plasma and glutathione peroxidase in red blood cells up to 2 wk before calving than did cows that shed fetal membranes in < 12 h. Results suggest that inadequate dietary antioxidants may increase oxidative stress, production of lipid peroxides, and incidence of retained fetal membranes in dairy cows.

Animal Feed↗
PubMed1993

Hypertension secondary to chlorpropamide with amelioration by changing to insulin.

A retrospective analysis of the records of 22 type II diabetics whose treatment had been changed from insulin to chlorpropamide was performed to investigate the relative effects of insulin and chlorpropamide on blood pressure. Although diastolic BP index was not significantly different between the treatments, systolic BP index was significantly higher on chlorpropamide than on insulin (141 +/- 3 v 135 +/- 3 mm Hg, P = .02). In 10 patients in whom insulin was reinstituted, systolic BP fell significantly (P < .005), suggesting that in type II diabetics chlorpropamide exerts a relative hypertensive effect in comparison to insulin.

Blood Pressure↗
PubMed1992

Neonatal compartment syndrome.

Two cases of forearm compartment syndrome in neonates are presented. The compartment syndrome may be initiated before actual delivery and may appear in an advanced stage. In both children good clinical results were achieved when standard guidelines for managing compartment syndrome and established Volkmann's contracture were applied. Although uncommon, compartment syndrome should be considered in the differential diagnosis of the neonate who is unable to move an extremity.

Compartment Syndromes↗
PubMed1992

Measurement of visceral blood flow with magnetic resonance imaging.

With the increasing application of magnetic resonance imaging (MRI) and MR angiography in parenchymal liver disease, methods are becoming more widely available for noninvasive measurement of visceral blood flow. Amplitude-based (time-of-flight) and phase-based techniques have proved effective for measurement of portal blood flow, and phase-sensitive methods are applicable to arterial flow measurements. Because respiratory motion degrades the quality of examinations in the abdomen, it is desirable to use methods that can generate flow information in a breath-hold period. Although substantial technical difficulties persist for quantitative arterial flow measurements in the abdomen, the technical requirements for venous flow are less stringent, and important clinical information can be derived using straightforward techniques. The authors describe the principles of flow measurement using time-of-flight and phase methods in visceral arteries and veins, and discuss their practical implementation. Clinical applications are discussed, based on the experience of the authors and others working in the field.

Blood Flow Velocity↗
PubMed1992

Real-time NMR beam-directed velocity mapping. V-mode NMR.

BACKGROUND: Currently available noninvasive techniques for measuring blood flow velocities are constrained by limited view orientations (Doppler ultrasound) or limited time resolution (magnetic resonance imaging, MRI). We describe an MRI technique for measuring flow velocities in real time at arbitrary orientations within a cylindrical volume or "beam": V-mode nuclear magnetic resonance (NMR). METHODS AND RESULTS: The technique was implemented on a standard 1.5-T clinical NMR imager with no special hardware and was tested on phantoms and human volunteers. The beam can be fired at rates up to 60 times per second, allowing measurements on a time scale that is appropriate for ungated cardiac studies. In phantoms, steady flow velocities were measured with the beam aligned along the direction of flow, and the measured velocities correlated well with the actual velocities (r > 0.99). The radial distribution of velocities in phantoms under constant flow conditions was also determined. In humans, flow of blood in the descending aortas of normal and aortic insufficiency subjects was measured. Distinctive backflow of blood because of aortic insufficiency was readily apparent. CONCLUSIONS: The V-mode NMR technique is capable of acquiring clinically relevant real-time blood flow information from any desired angle of view with no attenuation at bone or air-tissue interfaces.

Aorta, Thoracic↗
PubMed1992

The transverse carpal ligament. An important component of the digital flexor pulley system.

The effect of release of the transverse carpal ligament on the mechanics of the flexor tendons was investigated with use of a fresh-frozen cadaver model. A 25 per cent increase in the amount of excursion of the tendons that was consumed by motion of the wrist was demonstrated for the digitorum profundus tendons after transection of the transverse carpal ligament, and a 20 per cent increase was noted for the digitorum superficialis tendons (p < 0.001). These values represent 5.4 +/- 1.2 and 5.5 +/- 1.3 millimeters of bow-stringing for each group of tendons.

Humans↗
PubMed1991

Radial shortening for Kienböck disease.

The cases of twenty-nine consecutive patients (thirty wrists) who had radial shortening for the treatment of stages I through IIIB Kienböck disease were reviewed to assess the results of this procedure. Thirteen patients (45 per cent) had a history of trauma, and all thirty wrists had a negative ulnar variance (average, 2.8 millimeters) on radiographs. All wrists were re-examined after an average follow-up of 3.8 years (minimum, two years). At that time, the pain had decreased in 87 per cent of the wrists. Extension of the wrist had improved an average of 32 per cent; flexion, 27 per cent; radial deviation, 30 per cent; ulnar deviation, 41 per cent; and grip strength on the affected side, 49 per cent. Analysis of the radiographs by computer digitization showed no significant changes in the amount of collapse of the lunate at the latest follow-up. In two wrists, there were complications at follow-up (excessive shortening of the radius and non-union of the radial osteotomy). Radial shortening is an effective treatment for Kienböck disease in wrists that do not have degenerative changes in adjacent carpal joints. Pain, range of motion, and strength can be expected to improve, but the radiographic appearance of the lunate changes little, if any.

Adolescent↗