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Biomedical subjects

J Perry

Publications and source records attributed to J Perry.

At least 55 records · Page 3Linked to original sources
PubMed1988

In vivo oxidation of the methyl group of hepatic 5-methyltetrahydrofolate.

Methionine given parenterally to rats caused rapid disappearance of methyltetrahydrofolate from the liver and a corresponding rise in tetrahydrofolate and formyl-tetrahydrofolate concentrations. When [14C]H3--H4folate was given, methionine caused an increased [14C]0(2) excretion, indicating that oxidation of the methyl group had occurred. Methionine was more effective than S-adenosylmethionine at causing oxidation, but serine was ineffective. The lowest dose of methionine to produce an effect was 0.5 mumol, which is less than the daily dietary intake in a rat. The data suggest that the concentration of methylfolate in rat livers is controlled by the concentrations of methionine.

Adenosine↗
PubMed1988

ACR-NEMA digital imaging and communications standards: minimum requirements.

The purposes, implications, and history of development of the American College of Radiology-National Electrical Manufacturers Association (ACR-NEMA) Digital Imaging and Communication Standard and its contents are briefly described, and the minimum requirements of the ACR-NEMA Digital Imaging and Communication Standard are described with a concise introduction of each layer. The usefulness, validity, current status, and future development of the standard are also discussed.

Computer Systems↗
PubMed1988

Demyelination and decreased S-adenosylmethionine in 5,10-methylenetetrahydrofolate reductase deficiency.

We previously described demyelination in the brain and subacute combined degeneration of the spinal cord in a patient with 5,10-methylenetetrahydrofolate reductase deficiency. To assess the role of methionine, S-adenosylmethionine, folate, and neurotransmitter amine metabolism in the demyelination process, we measured these metabolites in CSF from this patient; the findings are compared with those obtained from three patients in whom neurologic deterioration had been halted by the administration of betaine. Folate concentrations were low, and amine and biopterin metabolism were abnormal in all patients. Methionine and S-adenosylmethionine concentrations were undetectable in the first patient. In those receiving betaine, methionine concentrations were proportional to the dose administered and S-adenosylmethionine concentrations were near normal. The results provide the first evidence for an association between defective S-adenosylmethionine metabolism and demyelination in humans.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed1988

Functional comparison of posterior cruciate-retained versus cruciate-sacrificed total knee arthroplasty.

Gait of 11 patients with bilateral paired posterior cruciate-retaining and cruciate-sacrificing total knee arthroplasties (TKA) was studied preoperatively and two years postoperatively on walking and stair climbing. Five-year clinical and roentgenographic examinations were included in the study. Differences between the two prostheses were noted both in level walking and in stair climbing. On level walking, cruciate-sacrificed TKA had more flexion in loading response and increased flexion and varus moments with increased muscle activity of quadriceps and biceps femoris. Abnormal gaits common to both types of knee were decreased flexion in stance and decreased single-limb stance. Both knees had a stiff-legged gait during stance. On stairs, the cruciate-sacrificed TKA substituted soleus muscle activity for knee stability. The single-limb stance and range of motion were similar for both knees. In clinical terms, the cruciate-sacrificed TKA is less efficient and has greater medial loading and higher joint reaction forces that may affect durability of the prosthesis. The five-year knee scores, patient satisfaction, and roentgenographic examinations were equal for both sets of knees.

Adult↗
PubMed1988

Informal communication networks and change in physicians' practice behavior.

This study used influential physicians to disseminate information concerning the advantages of developing and using computer-stored personal order sets with a hospital information system. The results indicate that continuing medical education delivered through influential physicians is an effective way of changing physicians' practice behavior.

Communication↗
PubMed1988

Tomorrow's nurses.

Explore the source record for details and available documents.

Career Choice↗
PubMed1988

Dynamic electromyographic analysis of the throwing shoulder with glenohumeral instability.

Fifteen male athletes who were skilled in throwing and who had chronic anterior instability of the shoulder (Group 1) were evaluated by dynamic intramuscular electromyography while pitching a baseball. Indwelling wire electrodes recorded the levels of activity in the biceps, middle deltoid, supraspinatus, infraspinatus, pectoralis major, subscapularis, latissimus dorsi, and serratus anterior throughout the entire pitching sequence. These signals were synchronized electronically with records of the pitch that were made using high-speed photography. The pitch was divided into five phases: wind-up, early cocking, late cocking, acceleration, and follow-through. The results were compared with previous identical studies of twelve healthy, uninjured male athletes who were skilled in throwing (Group 2). Activity increased mildly in the biceps and supraspinatus in Group 1 as compared with Group 2. Similar patterns of activity were demonstrated in the deltoid. In Group 1 the infraspinatus had increased activity during early cocking and follow-through but had decreased activity during late cocking. The pectoralis major, subscapularis, latissimus dorsi, and serratus anterior in Group 1 all were shown to have markedly decreased activity. The study revealed a difference between Groups 1 and 2 in all of the muscles of the shoulder that were tested with the exception of the deltoid. The mildly increased activity levels of the biceps and supraspinatus that were found in Group 1 may compensate for anterior laxity. The marked reduction in activity in the pectoralis major, subscapularis, and latissimus dorsi added to the anterior instability by decreasing the normal internal-rotation force that is needed during the phases of late cocking and acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The postpolio syndrome. An overuse phenomenon.

Persons with good recovery of function following their initial poliomyelitis are now, more than 30 years later, experiencing new weakness, fatigue, and muscle pain. The likelihood of muscle overuse being the cause of this late functional loss was investigated by dynamic electromyography (EMG) and foot-switch stride analysis in 34 symptomatic patients. Manual testing grouped the muscles, with strong (S) encompassing Grades Good (G) and Normal (N) while weak (W) included Fair plus (F+) to zero (0). After testing quadriceps and calf strength, the patients fell into one of four classes: strong quadriceps and calf (SQ/SC), strong quadriceps and weak calf (SQ/WC), weak quadriceps and strong calf (WQ/SC), or combined weak quadriceps and calf (WQ/WC). Quantified EMG (normalized by the manual muscle test EMG) defined the mean duration and intensity of the quadriceps, soleus, lower gluteus maximus, and long head of the biceps femoris during walking. Overuse was defined as values greater than the laboratory normal (mean + 1 SD). Each muscle exhibited instances of overuse, normalcy, and sparing. The biceps femoris was the only muscle with dominant overuse (82%). Quadriceps overuse was next in frequency (53%). Soleus activity infrequently exceeded normal function (34%), but this still represented more than twice the intensity and duration of the other muscles. Gluteus maximus action was also seldom excessive (34%). The patients averaged two muscles with excessive use during walking. Gait velocity of the SQ/SC strong group was highest (71% of normal) while the three categories that included weak muscles had walking speeds in the range of 50% of normal. The finding of muscle overuse during a single free-speed walking test that does not attain normal velocity supports the concept of muscle overuse being the cause of the patient's dysfunction.

Adult↗
PubMed1987

Impaired formylation and uptake of tetrahydrofolate by rat small gut following cobalamin inactivation.

The effect of inactivation of cobalamin by N2O on the intestinal absorption of folate was studied using rat everted gut sacs. Further, in view of uncertainties about the presence of methionine synthetase in gut [1], this enzyme was measured. Everted gut sacs were incubated with [2-14C]tetrahydrofolate, and the subsequent appearance of labelled formyl- and methyl [14C] tetrahydrofolate in everted segments of small intestine of rats was studied. Considerable methionine synthetase activity was present in washed everted gut sacs but not in gut segments in the absence of such treatment. Methionine synthetase activity declined after exposure to N2O, which oxidizes and inactivates cob(I)alamin. Folate uptake by gut sacs was not affected by 24 h exposure of the animals to N2O but fell significantly after 7 days exposure. There was a significant fall in the amount of formyltetrahydrofolate formed after cobalamin inactivation and this was reversed by supplying either methionine, methylthioadenosine or sodium formate. Serine had no effect. The data support the hypothesis that methionine and methylthioadenosine act by supplying single carbon units at the formate level of oxidation.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1987

Lisfranc fracture-dislocations of the foot: a clinical-kinesiological study.

Twenty-three patients with Lisfranc fracture dislocation of the foot were reviewed at an average of 19.4 months following injury. Results were assessed by a subjective questionnaire, physical examination, and radiographic analysis. There were 10 good (43.5%), 10 fair (43.5%), and 3 poor (13.0%) results. A subgroup of 11 patients underwent gait analysis in the pathokinesiology laboratory. No patient had a normal gait following a displaced Lisfrance fracture. Limp was thought to be due to a prolonged hindfoot period, and a delayed and shortened period of weight transfer through the midfoot to the forefoot as a result of pain inhibition. The best results both clinically and by gait analysis were achieved in those patients who had anatomic reductions.

Adult↗
PubMed1987

Energy cost of three-point crutch ambulation in fracture patients.

The energy consumption associated with unilateral nonweight-bearing (three-point) crutch ambulation was evaluated in a group of 25 newly injured fracture patients immobilized in a long or short leg cast. After 5 min of crutch ambulation, the rate of oxygen uptake was 32% greater than the value for normal walking (averaging 15.7 ml/kg-min); the heart rate was 53% greater than normal (averaging 153 beats/min); and the respiratory quotient was markedly elevated (averaging 1.03). In those subjects able to ambulate for 10 min, these values averaged 17.6 ml/kg-min and 173 beats/min, approaching the peak values for maximal upper extremity exercise. The prescription of three-point crutch ambulation is a severe exercise challenge requiring strenuous arm and shoulder exertion under anaerobic conditions. These findings account for the common clinical experience that the newly injured fracture patient, unable to weight bear on an injured limb and requiring crutches, is a severely restricted ambulator.

Adult↗
PubMed1987

Distal rectus femoris transfer.

A major concern in the management of children with cerebral palsy is crouch gait with its excessively flexed knee and hip stance. Earlier, attention was given to the flexed hip and it was assumed that the rectus femoris, as an active component of the quadriceps, contributed an unwanted effect. Proximal surgical release of the rectus from its attachment on the ilium was recommended. However, dynamic electromyographic records of 45 children with cerebral palsy demonstrated that the rectus more commonly was active in the swing phase, and such an approach is appropriate only when electromyography confirms that rectus function is occurring in stance. The recording technique must be capable of differentiating rectus femoris action from that of the underlying vasti, which surface electrodes are not able to do. Past experience indicates that routine inclusion of a proximal rectus femoris release (without confirmation that the muscle's action was limited to stance) resulted in the patient having a stiff-legged gait. Hence the actions of the rectus femoris need closer attention.

Cerebral Palsy↗
PubMed1987

Rectus femoris transfer to improve knee function of children with cerebral palsy.

Stance phase stability and swing phase clearance, prerequisites for normal ambulation, often are lost in the gait of children with cerebral palsy. Lengthening of the hamstrings usually will improve stance-phase knee extension but will not greatly alter swing-phase knee flexion. This paper presents the outcome of transfer of the distal end of the rectus femoris in conjunction with hamstrings lengthening in 37 knees, and compares it with a control group of 24 knees in which only hamstrings lengthening was done. In the first group swing-phase knee flexion was improved by 16.0 +/- 14.4 degrees, compared to 9.5 +/- 7.5 degrees in the control group, and residual knee flexion in stance was reduced to 8.9 +/- 8.1 degrees, compared to 15.1 +/- 13.8 degrees in the controls. Poor outcome in the transfer-plus-lengthening group was associated mainly with foot rotation in excess of 8 degrees internally or externally, or postoperative knee flexion in stance. Criteria for selection of cases and methods of improving surgical outcome are discussed.

Adolescent↗
PubMed1987

Selective tarsal arthrodesis: an in vitro analysis of the effect on foot motion.

Five different intertarsal arthrodeses were simulated in 15 fresh cadaver feet/ankles utilizing external fixation. Pin placement was verified radiographically. Range of motion measurements were performed before pin placement, after pin placement, and after simulated arthrodesis. The deficit in foot motion created by selected limited intertarsal fusions was then measured. The prearthrodesis range of motion measurements were found to be dorsiflexion (DF), 27 degrees; plantarflexion (PF), 57 degrees; total inversion (INVT), 29 degrees; eversion total (EVT), 22 degrees; hindfoot varus (VRH), 16 degrees; hindfoot valgus (VLH), 12 degrees. The deficits in motion after arthrodesis were as follows. Ankle (tibiotalar): DF, 50.7%; PF, 70.3%; INVT, 8.7%; EVT, 9.4%; VRH, 34.6%; VLH, 27.8%. Hindfoot arthrodesis (Tibiotalar calcaneal): DF, 53%; PF, 71.3%; INVT, 49.5%; EVT, 47.6%, VRH, 100%; VLH, 100%. Pantalar (Tibotalar calcaneal cuboid navicular): DF, 62.8%; PF, 82.2%; INVT, 71.7%; EVT, 67.4%; VRH, 100%; VLH, 100%. Triple (Talocalcaneal cuboid navicular): DF, 12.5%; PF, 15.5%; INVT, 50%; EVT, 51.4%; VRH, 60.5%; VLH, 60.5%. Total tarsal arthrodesis: DF, 78.5%; PF, 90.2%, INVT, 87.5%; EVT, 83.6%; VRH, 100%; VLH, 100%.

Ankle Joint↗
PubMed1987

Contractures. A historical perspective.

Orthopedic history vividly documents the continuing battle between restoring tissue stability and preserving functional mobility. Prolonged and uninterrupted rest, popularized by Hilton and Thomas, but promoted by many before them and subsequently continued by Jones, Orr, and others, assures healing. Contractures that permanently limit function are not an uncommon consequence. Hippocrates, Hunter, Lucas-Championniere, and David advocated judicious motion. Timing and the interpretation of the patient's pathologic state have proved to be the critical criteria. Modern antibiotics, antiinflammatory medications, acute surgical repair, and techniques that combine stability and early motion provide today's orthopedic surgeons' great versatility and capability. Despite these advantages the threat of contractures remains. The dictum "rest until healed" persists. Physiologic posturing of inflamed or swollen joints to minimize tissue strain introduces resting positions of 15 degrees plantar flexion at the ankle, and 30 degrees flexion at the knee and hip. These will be perpetuated by contractures if not actively counteracted by timely mobilizing procedures. Each of these joint positions is a serious deterrent to walking without stressful substitutive posturing, and the patient's ability to function is impaired.

Contracture↗
PubMed1987

Surgical treatment of displaced olecranon fractures by tension band wiring technique.

Forty-five displaced olecranon fractures including 14 accompanying dislocated radial heads and seven radial head fractures were treated over a 13-year period by the tension band wiring technique. The use of supplemental internal fixation when necessary allows excellent results with the use of this technique, even in the presence of severe comminution or radial head dislocation. Primary silicone radial head implants fractured in all three patients in which they were used, necessitating repeat surgery in two patients to date. While loss of motion in terminal extension was a common aftermath of displaced olecranon fracture (59%), it was usually minor and functionally insignificant. True Kirschner-wire migration was not a common problem and can probably be eliminated by proper technique. The presence of gaps in the intraarticular surface of the semilunar notch of the ulna produced no ill effects and was compatible with excellent results. If only those cases with isolated olecranon fractures in this series are considered, there were good and excellent results in 29 of 30 cases (97%). Excision of the olecranon fragment(s) should be reserved for those cases when anatomic restoration cannot be achieved with internal fixation.

Adolescent↗
PubMed1987

The energy cost of walking with arthritis of the hip and knee.

The physiologic energy expenditure of walking was measured in patients with severe arthritis. Nine patients were tested following Girdlestone hip resection arthroplasty, six patients prior to total knee arthroplasty (TKA) for unilateral osteoarthritis of the knee, and 49 rheumatoid arthritis patients prior to unilateral TKA; 27 were retested after operation. The results were compared with previously published pre- and postoperative data for total hip arthroplasty (THA) following primary osteoarthritis. There were severe energetic penalties caused by rheumatoid or osteoarthritis involving the hip or knee or following Girdlestone arthroplasty. Walking speed was severely reduced in all groups (range, 33-46 m/minute). The rate of oxygen consumption was not significantly greater than the mean rate of oxygen uptake for normal subjects; however, the oxygen cost per meter travelled was elevated because of the slow walking speed. The heart rate was significantly elevated in all patient groups. The elevated cardiac response can be accounted for on the basis of deconditioning resulting from the patients' pain, limited ambulatory activities, and the systemic effects of rheumatoid disease. In addition, the elevated cardiac response may be caused by added physical exertion by the arms in patients on crutches or walkers. The improvements in speed and energy cost were the same for the group of rheumatoid patients tested after unilateral TKA as in the group of patients tested before and after THA. The clinician can anticipate the same magnitude of improvement from surgery in a rheumatoid patient as in an osteoarthritis patient if the primary joint disease is restricted to a single joint.

Arthritis, Rheumatoid↗