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Biomedical subjects

R E Hunter

Publications and source records attributed to R E Hunter.

72 records · Page 4Linked to original sources

The absorption of iron as supplements in infant cereal and infant formulas.

The absorption of iron was measured from isotopically tagged salts used in supplementing infant cereals and as the iron supplement in cow's milk and soy-based formulas. Iron as sodium iron pryophosphate and ferric orthophosphate were poorly absorbed from infant cereal (mean, smaller than 1.0%) and thus are not dependable sources of iron to meet the nutritional needs of infants. Reduced iron of very small particle size and ferrous sulfate when added to cereal was absorbed to a greater extent (mean, 4.0% and 2.7% respectively). For technical reasons, these two forms of iron had not been added to commercial cereal products because of discoloration, distribution problems of the iron in the product, and shortened shelf life. Therefore, at the present time, iron supplementation of infant cereals with sodium iron pyrophosphate, ferric orthophosphate, and reduced iron of large particle size does not provide a predictable and available source of iron to meet the needs of infants. Supplemental iron as ferrous sulfate in milk- and soy-based formulas gave a mean absorption of 3.4% and 5.4%. The iron supplements in these formulas can essentially meet the needs for dietary iron of healthy infants.

Animals↗

Meigs syndrome and ovarian fibroma: CT findings.

We present a case of ovarian fibroma with associated Meigs syndrome, Even though the CT findings of ovarian fibroma have been reported previously, our case, with associated meigs syndrome, demonstrated a broader spectrum of CT findings.

Female↗

Comparison of the biochemistry of proteoglycans isolated from normal, idiopathic scoliotic and cerebral palsy spines.

Six levels of anulus and nucleus were obtained from each of three spines: one with idiopathic scoliosis, one with cerebral palsy, and one age-matched control. Proteoglycans from all spines had the same extractability and distribution in the associative and dissociative cesium chloride density gradients. In all cases, the anulus differed from the nucleus samples in terms of all the parameters studied. There was no difference between the cerebral palsy and idiopathic scoliotic values. However, they both differed from the control values, having significantly higher levels of aggregate and larger nonaggregating monomers, but no significant differences in proteoglycan monomer chemistry. Results indicate that idiopathic scoliosis may not be the result of a biochemical alteration in proteoglycan but that curvature per se may lead to an alteration in the proteoglycan composition, particularly in the nucleus pulposis.

Adolescent↗

The effect of wearing the complete Lenox Hill Derotation Brace on energy expenditure during horizontal treadmill running at 161 meters per minute.

Ten volunteer subjects (means age = 26.6 +/- 4.9 years, means height = 177.9 +/- 5.6 cm, and means weight = 76.9 +/- 11.2 kg) who had been wearing the Lenox Hill Derotation Brace (LHB) for a mean time of 23.9 +/- 28.0 months were familiarized with horizontal treadmill running at 161 m/min with and without the LHB. They were then tested randomly for four runs, two with the LHB and two without the LHB. Metabolic measurements using a device that counted footstrikes on the treadmill were taken during the 3rd and 6th minutes of each run. Regardless of sampling time, wearing the LHB produced significantly higher values for VO2 (4.58%, P less than 0.025) and heart rate (5.10%, P less than 0.004) compared to the no brace condition. Regardless of whether or not the subjects were wearing the LHB, 6 minute values were significantly higher than 3 minute values for VO2 (5.89%, P less than 0.0004), VE (10.8%, P less than 0.004), heart rate (5.35%, P less than 0.0000), and R (2.17%, P less than 0.038). The mean 6 minute values of VO2 with (37.42 +/- 3.55 ml/kg/min) and without (35.54 +/- 2.17 ml/kg/min) the brace fall within the range of expected values of 28.1 to 39.3 ml/kg/min derived from regression equations from the literature which predict VO2 response to horizontal treadmill running. Mean stride lengths while wearing the LHB (97.85 cm) were not significantly different from mean stride lengths without the LHB (98.56 cm). It is concluded that wearing the LHB produces a 4.58% increase in energy expenditure during horizontal treadmill running at 161 m/min which cannot be attributed to changes in stride length or to time of sampling during the run.

Adult↗

Load sharing and graft forces in anterior cruciate ligament reconstructions with the Ligament Augmentation Device.

Buckle transducers were used to directly measure load sharing and overall force in three segment (semitendinosus, gracilis, Ligament Augmentation Device) and two segment (patellar tendon, LAD) composite ACL grafts during the application of anteriorly directed loads to a series of five fresh knee specimens with a pneumatic load apparatus. The total graft forces generated in the two segment and three segment composite reconstructions during this immediate postoperative state were highly variable when compared to the normal ACL in each specimen, and were irreproducible among the five specimens. Load sharing among the graft components occurred and was also variable in both reconstructions, with this variation being greater in the three segment graft. The LAD carried an average of 45% of the total graft force in the three segment graft and 28% in the two segment graft. Further work is required to clarify the source of the variability in the total graft force and load sharing observed in this study.

Biomechanical Phenomena↗

Graft force-setting technique in reconstruction of the anterior cruciate ligament.

The objective of this work was to present a method for controlling the mechanical state of the knee during graft fixation in an ACL reconstruction; that is, adjusting the unloaded length of the graft at the time of fixation so that the force-carrying characteristics of the graft match that of the intact ACL, when the normal and reconstructed knees are subjected to the same external load. To demonstrate the new method, an experimental knee testing system was used to measure ligament and graft forces with buckle transducers, as external loads were applied to five fresh knee specimens with a pneumatic load apparatus. ACL and collateral ligament force data were collected as anteriorly directed loads of 90 N (20 pounds) were applied at 0 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion in the normal intact knee and the same knee following ACL excision. A composite graft was prepared, consisting of distally based semitendinosus and gracilis autogenous tissue augmented with the Kennedy Ligament Augmentation Device. Femoral fixation was obtained using a fixation plug that was inserted through the lateral femoral condyle. With a 90 N anterior tibial load applied at 30 degrees of flexion and a single buckle transducer measuring the total composite graft force, the graft length was varied using the fixation plug until the force matched that seen by the intact ACL under the same loading condition. The graft was then clamped in the fixation plug and the anterior load sequence at the four flexion angles was applied to this reconstructed knee state.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗

The effect of an iliotibial tenodesis on intraarticular graft forces and knee joint motion.

Lateral extraarticular reconstructions are used as isolated procedures in knees with moderate rotatory instability and as "backups" in knees requiring primary repair or intraarticular reconstruction for major rotatory instability. We used an experimental knee testing system to analyze the immediate postoperative mechanical effect of an iliotibial band tenodesis on an intraarticular reconstruction of the ACL in fresh cadaver knees using a composite graft consisting of a bone-patellar tendonbone segment augmented with the Kennedy Ligament Augmentation Device (LAD, 3M Co., St. Paul, MN). The intraarticular graft was standardized by using a forcesetting technique. Ligament and graft forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to seven fresh knee specimens at 0 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion. The following knee states were tested in each specimen: intact ACL, excised ACL, intraarticular reconstruction, intraarticular reconstruction with the tenodesis added, and tenodesis with the intraarticular reconstruction added. Adding the iliotibial band tenodesis to an existing standardized intraarticular reconstruction significantly decreased the force in the ACL composite graft by an average of 43%. When the standardized intraarticular reconstruction was added to an existing tenodesis, the graft forces were an average of 15% below the level of when the reconstruction was performed alone. The force in the tenodesis was significantly less than the composite graft force at extension; however, the differences between the tenodesis and total graft force were not significant from 30 degrees to 90 degrees of flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗

Effect of anterior cruciate ligament graft tensioning direction, magnitude, and flexion angle on knee biomechanics.

The objective of this study was to determine the biomechanical effect of graft tensioning during reconstruction of the anterior cruciate ligament. We evaluated the magnitude of the tensioning force (22 or 67 N), the flexion angle at which the tension was applied (extension or 30 degrees of flexion), and the direction of application of the tensioning force (proximal, distal, or distal with a posterior force simultaneously applied to the tibia) on 10 fresh cadaveric knees. The anterior cruciate ligament was reconstructed using a bone-patellar tendon-bone graft. The graft was then temporarily fixed during the application of each of 12 combinations of tensioning variables listed above. After each fixation, graft force and joint motion were measured during anterior tibial loads. Tensioning direction and the flexion angle significantly affected graft force and joint motion, while the magnitude of the graft tensioning did not. Graft forces were greater when the tensioning was applied at 30 degrees of flexion. Compared with distal tensioning with and without posterior tibial force, graft forces with proximal tensioning were greater in extension and lower in flexion. The position of the tibia relative to the femur was posterior and externally rotated, compared with normal, for all combinations of tensioning variables in both unloaded and anterior load states.

Anterior Cruciate Ligament↗

The snowboarder's foot and ankle.

We undertook a prospective study to determine the type and distribution of foot and ankle snowboarding injuries. Reports of 3213 snowboarding injuries were collected from 12 Colorado ski resorts between 1988 and 1995. Of these, 491 (15.3%) were ankle injuries and 58 (1.8%) were foot injuries. Ankle injuries included 216 (44%) fractures and 255 (52%) sprains. Thirty-three (57%) of the foot injuries were fractures and 16 (28%) were sprains. The remaining injuries were soft tissue injuries, contusions, or abrasions. There was no significant correlation between boot type (soft, hybrid, or hard) and overall foot or ankle injury rate. There were significantly fewer ankle sprains in patients wearing hybrid boots and fewer fractures of the lateral process of the talus in patients wearing soft boots. An unexpectedly high number of fractures of the lateral process of the talus were noted. These 74 fractures represented 2.3% of all snowboarding injuries, 15% of all ankle injuries, and 34% of the ankle fractures. Many of these fractures are not visible on plain radiographs and require computed tomography imaging to be diagnosed. Diagnosis of this fracture pattern is paramount; the physician should be very suspicious of anterolateral ankle pain in the snowboarder, where subtle fractures that may require surgical intervention can be confused with anterior talofibular ligament sprains.

Ankle Injuries↗

Acute skier's thumb repaired with a proximal phalanx suture anchor.

The purpose of this study was to determine the functional outcome of a surgical technique for the repair of injuries of the ulnar collateral ligament of the thumb. A 14-point questionnaire was developed to determine functional outcome after surgical repair of acute ulnar collateral ligament rupture. Early ulnar collateral ligament repair was performed on 58 patients with grade III sprains (complete rupture) of the ligament using a new technique that employs a suture anchor for fixation. Forty-five patients were interviewed at a minimum postoperative interval of 12 months and were included in this study. Forty-four patients (98%) believed they had a stable repair, were satisfied with their surgery, and would have it again if necessary. Forty-four patients (98%) were not hindered in their day-to-day activities and had a functional range of motion. Mild discomfort was felt by eight of our patients (17%), but only three patients (7%) had pain with activities. The average time to return to skiing was 1.7 days. The use of a suture anchor provided a strong and stable repair if the surgery was performed early.

Activities of Daily Living↗

Skiing injuries.

Skiing is a winter sport enjoyed by approximately 200 million people worldwide. An overall injury rate of approximately 3 per 1000 skier-days means that skiing certainly is the riskiest sport undertaken by adults on a routine basis. However, the data suggest that one can anticipate years of enjoyable recreation free from injury. Many troubling injuries, particularly to the lower leg, have shown a steady decline over the past 20 to 30 years because of advances in boot design and binding capabilities. In addition, as information has been gathered regarding the importance of proper maintenance and adjustments, equipment now available can protect a skier more effectively than at any time in the past. Nevertheless, skiing continues to present inherent risks that can be minimized through the following strategies: 1. Enroll in a conditioning program before skiing that focuses on strength and endurance components particularly of the legs and back. 2. Have equipment that is compatible with the skier both from the standpoint of size and expertise. 3. Have equipment adjusted professionally. 4. Do routine testing of binding releases each day before beginning to ski. 5. Ski under control at speeds that are consistent with ability. 6. Stop skiing before fatigue becomes the limiting factor.

Adult↗

Nursing assessment and care plan statements.

Scope, specificity, and interrelatedness of patient problem and nursing intervention statements on nursing care plans were studied in relation to the introduction into the nursing assessment process of an objective observation checklist and a nursing history form. Ninety nursing care plans from six inpatient units in a Veterans Administration hospital were studied over an 11-month period. Results indicated that significant increases in the numbers of both types of care plan statements occurred only following the introduction of the nursing history, as did the numbers of nursing interventions related to the identified patient problems. The degree of specificity among the problem statements increased, but nursing interventions tended to become less explicit. The scope of focus of both types of statements continued to be primarily physical in orientation. The findings also suggested that, since the care plans reflected less than half the patient problems identified on the nursing histories, care plan studies alone might not be appropriate for evaluating the breadth of nursing care planning.

California↗