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Bone plate fixation was reviewed in 29 distal radial fractures of small- and miniature-breed dogs. Twenty-two fractures in 18 dogs were available for follow-up. Number of complications and return to function were evaluated. Complications occurred in 54% of the fractures. Catastrophic complications occurred in 18% of fracture repairs with follow-up, while minor complications occurred in 36%. Sixteen (89%) of 18 dogs had a successful return to function. Bone plate fixation is a successful repair method for distal radius and ulna fractures in small-breed dogs, compared to previously reported methods.

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Micelles and vesicles coexist in native bile. Mixed micelles are composed of bile salt, phospholipid, and cholesterol. Micellar bile salt is in equilibrium with the aqueous phase bile salt (intermicellar bile salt), and mixed micelles can be converted to cholesterol-phospholipid vesicles by depletion of bile salt. To determine the amount of cholesterol carried in vesicles and micelles, these two populations must be separated without altering the relative proportion of each. Based on the size difference between micelles and vesicles, gel filtration chromatography has been used to accomplish this separation. We reasoned that to maintain the proportion of micelles and vesicles in bile, the column must be equilibrated and eluted with buffer containing the intermicellar bile salt concentration (IMBC) and species. To test this hypothesis we created a model bile composed exclusively of micelles, a solution containing micelles and vesicles, and a model bile containing all vesicles, as demonstrated by quasielastic light scattering. Gel filtration on Sepharose 4B demonstrated that model vesicles and micelles could be separated on a column eluted with buffer containing bile salt at the IMBC. However, a modest decrease in the buffer bile salt concentration (less than 1 mmol/L) resulted in complete conversion of micelles to vesicles. A comparable increase in the buffer bile salt concentration converted vesicles to micelles. Using only taurocholate in the eluting buffer at the IMBC caused a complete shift of micelles to vesicles, whereas using only taurochenodeoxycholate resulted in conversion of vesicles to micelles. An initial collection of rat bile separated on a column equilibrated with the measured IMBC demonstrated that 94% of the cholesterol was in the micellar fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

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Recurrent hip dislocation after corrective orthopaedic surgery in children and teenagers with intermediate spinal atrophy has not been reported in the literature. Four cases with long-term follow-up are presented. These represent the only cases surgically treated in 30 years of following spinal atrophy patients. Thus, it seems significant that all hips redislocated after the surgical procedure. In addition, two patients had second operations with subsequent dislocation. Pelvic obliquity should not be the basis for the surgery, as spinal fusion is generally necessary for wheelchair users. The sagacity of performing surgery for hip dislocations is raised.

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Three children were presented having similar facies, musculoskeletal anomalies and a common ethnic background. All had dislocated hips, scoliosis, congenital vertical tali and hand deformities. There was a very small web space between the first and second metacarpals, extension deformities at the wrist, flexion deformities at the metacarpophalangeal joints, and at one or more proximal interphalangeal joints. In addition, 2 of the 3 youngsters had marked crowding of the teeth and a small maxillary arch. All laboratory studies were normal. The most alarming finding was the poor wound healing which averaged 48%. The wound complication rate at Shriner's Hospital in San Francisco during the identical period of time these children were treated ranged from 1.2% to 1.8%. It is believed that this represents a new syndrome, as similar cases could not be found in the literature. The orthopedist may treat these anomalies in the standard fashion but should keep in mind the propensity for poor wound healing in these patients. The common ethnic background was that of Spanish-American or Chicago families.

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Fifty hips in forty-four children with Legg-Calvé-Perthes disease, treated at the Shriners Hospital for Crippled Children, San Francisco, were evaluated with a simplified method of Catterall's classification. Our data indicate that the Catterall rating changed in 40 per cent of the hips when they were classified before they had reached the fragmentation stage of Waldenström compared with only 6 per cent when they were classified after fragmentation had occurred.

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In 15 patients with arthrogryposis multiplex congenita, 18 operations were performed to improve elbow function. These operations were for seven cases of pectoralis transfer, seven cases of anterior transfer of triceps, two cases of posterior elbow release, and two cases of Steindler flexoroplasty. Results were evaluated on two simple criteria: single-hand feeding and improved elbow joint motion. These criteria showed that the pectoralis transfer was the most effective procedure.

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The role of the calf muscles during the single-limb stance phase of gait was assessed in fifteen normal subjects and in seven with either an amputation or a neuromuscular deficit. Normal activity of the muscles, paralysis by nerve blocks, and stability versus instability of the ankle were studied. Pelvic displacement and velocity, step length, and step time were evaluated for each limb during the gait cycle, and the contribution of activity of calf muscles to each was determined. Limb-segment position, lower-limb joint angles, over-all cadence, velocity, and stride length were measured to reveal compensatory mechanisms in the absence of muscle strength in the calf. The results indicate that the force produced by activity of calf muscles is used to restrain the body's own forward momentum and not used to propel it further. Absence of the calf muscle causes an immediate compensatory reaction directed toward maintaining over-all stability rather than speed.

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Two theories concerning the effects of surgical release of the proximal origins of the rectus femoris in spastic patients are (1) that release reduces hip flexion contracture and lumbar lordosis and diminishes crouch, and (2) that release primarily enhances early swing-phase knee flexion. A series of eight patients with pre-operative electromyography and pre- and post-operative dynamic knee measurements are reviewed. In these patients, back-knee thrust did not improve because it was not caused by rectus contracture. The effect upon hip was also variable: two patients had increased hip flexion and a third had diminished hip flexion after release. In six of the eight patients knee flexion was improved in early swing phase. Improvement from surgery can be expected when rectus spasticity is sufficient (1) to interfere with the initiation of swing phase, and (2) to decrease the amplitude of knee flexion. Little change occurred in the patients who did not have these functional deficits. A review of the cases supports the primary knee effect theory of Silfvenskiöld; however, insufficient information was obtained from this series to rule out hip and pelvic changes.

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This study was performed to determine the mechanism whereby hypertonic sucrose inhibits the immune bactericidal reaction. Other investigators had postulated that the initial attack of complement (C) on the cell wall was followed with lysozyme-containing whole serum by an enzymatic reaction upon the peptidoglycan substrate resulting in cell death. In the absence of serum lysozyme, secondary lethal changes might occur from damage to the cell's inner membrane as a result of osmotic forces in the presence of a defective cell wall. Hypertonic sucrose giving rise to plasmolysis and protection of the inner membrane was presumed to differentially inhibit the immune response mediated by lysozyme-free serum. The experimental results observed in this investigation have indicated, however, that the inhibitory effect of sucrose upon the bactericidal reaction may be explained simply by its anticomplementary effect and not by any effect on the bacterial cell. This view was supported by the following observations: (i) the comparability of the inhibitory effect of sucrose upon the immune hemolytic and bactericidal reactions, (ii) the comparable percentage loss in bactericidal activity of whole serum and lysozyme-free serum resulting from hypertonic sucrose, (iii) bactericidal antibody titrations were relatively unaffected and C titrations markedly inhibited by sucrose, (iv) the inhibitory effect of sucrose on the bactericidal reaction was unaffected by prior growth of the organism in the presence of sucrose, (v) the kinetics of the bactericidal reactivity of lysozyme-free serum in hypertonic sucrose, compared with whole serum, did not reveal a prolonged lag phase with lysozyme-free serum, but simply diminished reactivity at all times. These observations are compatible with the view that the C attack upon the outer surface of gram-negative bacteria, which plays a part in the cell's permeability control, may account for cell death. In this regard, the immune bactericidal reaction is quite comparable to the lysis of red cells or nucleated cells by C despite the lack of overt lysis in bacteria, probably because of their underlying supporting structures.

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The sensitivity of different bacteria to actinimycin D was not related to their cell surface morphology. Bacteria with simple and complex surfaces were both extremely susceptible.

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