Kinematic CT of the patellofemoral joint.

OBJECTIVE: The purpose of this study was to determine if kinematic CT can be applied to the patellofemoral joint using current slip-ring CT scanner design in patients with anterior knee pain and thus a suspected patellar tracking disorder. SUBJECTS AND METHODS: Twenty knees in 18 patients with anterior knee pain were evaluated with kinematic CT. A single 10-sec exposure of the patellofemoral joint was obtained during active flexion and extension. Static nonkinematic and loaded kinematic examinations were compared with unloaded kinematic studies in a subset of patients. The changes in lateral patellofemoral angle and lateral shift were measured. Video cine viewing of patellofemoral motion was used to subjectively grade image quality and patellofemoral abnormalities by consensus. RESULTS: Kinematic CT was successfully used in all 20 knees. In nine knees studied with static nonkinematic and unloaded kinematic images, the lateral patellofemoral angle improved an average of 4" on the kinematic images. In addition, lateral shift improved by an average of 3%, an improvement that was statistically significant (p = .01). In 10 knees studied with and without loading, the lateral patellofemoral angle decreased an average of 3% with loading. No significant change was seen in lateral shift. In all patients, cine viewing was thought to be more useful than single images. Cine viewing was of good or diagnostic quality in all 20 knees studied. Lateral patellar translation during extension was detected in eight of 20 kinematic studies. Lateral patellar tilting also was detected in eight of 20 kinematic studies. Narrowing of the articular space was detected in 12 of 20 knees. Six knees were determined to be normal. CONCLUSION: Kinematic CT with slip-ring technology is a new technique that can be easily performed on the patellofemoral joint. This technique shows promise as a tool for determining the cause of anterior knee pain.

The Pavlik harness and developmental dysplasia of the hip: has ultrasound changed treatment patterns?

Monitoring Pavlik harness therapy for developmental dysplasia of the hip (DDH) has been used at our institution since 1986. In this study, we compared Pavlik therapy for DDH without ultrasound monitoring (group A) to similar therapy with ultrasound monitoring (group B). Both groups had similar age at diagnosis. Treatment failure was recognized earlier in group B than in group A (4.9 vs. 9.3 weeks). The total number of radiographs was significantly decreased in group B. The duration of therapy was less in group B than in group A. Successfully treated hips had an average increase in alpha angle of 8.4 degrees per month. The average failure rate in hips resting in a dislocated position at the onset of Pavlik therapy was unchanged by Pavlik monitoring.

Kinetics of leukocyte sequestration in the lungs of acutely septic primates: a study using 111In-labeled autologous leukocytes.

To further clarify the role of leukocytes in the pathogenesis of ARDS, we studied the localization and kinetics of leukocyte migration using 111In-labeled autologous white cell scans (111In wbc scans) in four primates made acutely septic with infusions of Escherichia coli. Whole body images were obtained with a gamma camera and were acquired on computer every 15 min beginning immediately after the E. coli infusion. Simultaneous measurements of C5a and peripheral blood leukocyte count were also obtained. Within 5 min of initiating sepsis, three major events occurred: complement activation as measured by the production of C5a, a profound fall in peripheral leukocyte count, and a significant increase in the sequestration of leukocytes in the lungs. The pulmonary sequestration reached a peak at 15 min with a mean of 152% of baseline activity. This sequestration consisted of a population that was predominantly neutrophils. Damage to the pulmonary capillary endothelium was demonstrated by an increase in extravascular lung water. The results support a role for neutrophils and complement as mediators in the pathogenesis of ARDS.

Complement levels in septic primates treated with anti-C5a antibodies.

During gram-negative sepsis it is known that endotoxin activates complement by the alternate pathway. The complement anaphylatoxin C5a, a result of this activation, is thought to play a key role in attracting and activating neutrophils in the lungs, leading to the adult respiratory distress syndrome. Complement levels were measured in primates made septic by Escherichia coli infusions. Anti-human C5a antibodies were administered to study their effect on neutrophil-mediated lung injury. Control (I), septic (II) and septic + anti-C5a antibody (III) groups (n = 4) were studied. The antibody-treated group (III) demonstrated a significant attenuation of septic shock and pulmonary edema as has been previously reported. All complement profiles were corrected for varying hemoglobin concentrations. C3, C4, and C5 levels were measured by radial immunodiffusion and were depleted in both septic groups. Once the levels were depleted from the plasma, they did not recover. The depletion of C4 indicates that classical pathway activation also occurred. C3a, C4a, and C5a levels were measured by radioimmunoassay. Significantly increased peak levels were reached in the septic groups 15 min after initiation of the E. coli infusion. There were no significant differences in early peak C3a and C4a levels between groups II and III. However, the mean peak C5a level in group III (anti-C5a antibodies) was 42% lower than that in group II, and after this early peak, C5a levels were not elevated above control levels in group III. The antibody to human C5a was thus shown to be cross-reactive with primate C5a and was specific since C3a and C4a levels were not decreased in group III.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of specific sheath cell proteins during peripheral nerve growth and regeneration in mammals.

Protein synthesis in the nerve sheath of injured as well as intact mature and developing sciatic nerves from rat and rabbit was investigated by incubating segments of nerve with [35S]methionine in vitro. The composition of labeled proteins under the different conditions of nerve growth was analyzed by two-dimensional gel electrophoresis and fluorography. The expression of six secreted proteins in rat sciatic nerve with the apparent molecular weights of 70,000 (70 kD), 54,000 (54 kD), 51,000 (51 kD), 39,000 (39 kD), 37,000 (37 kD), and 30,000 (30 kD) was of particular interest because of the correlation of their synthesis and secretion with aspects of nerve growth and regeneration. The synthesis of the 37-kD protein was significantly stimulated during both sciatic nerve development as well as regeneration but not in the intact mature nerve. The expression of this protein appears to be regulated by signal(s) from the axon but not the target. The 70-kD protein was exclusively synthesized in response to axotomy, thus confining its role to some aspect(s) of nerve repair. In contrast, the 54- and 51-kD proteins were expressed in the intact mature nerve sheath. Their synthesis and release was rapidly inhibited upon axotomy but returned to normal or higher levels towards the end of sciatic nerve regeneration, suggesting a role in the maintenance of the integrity of the mature (nongrowing) rat nerve. The 39- and 30-kD proteins were only transiently synthesized within the first week after axotomy. Two proteins with the apparent molecular masses of 70 and 37 kD were synthesized in denervated rabbit sciatic nerve. The similar molecular weights, net charges, and time-courses of induction suggest a homology between these proteins in rabbit and rat, indicating common molecular responses of peripheral nerve sheath cells to axon injury in both mammalian species.

A specific 37,000-dalton protein that accumulates in regenerating but not in nonregenerating mammalian nerves.

A 37-kilodalton protein is synthesized at higher rates in the peripheral and central nervous system of newborn rats than in adult animals. As a specific response to denervation, the synthesis of the 37-kilodalton protein is increased in the mature peripheral and central nervous system; however, this protein accumulates only in the peripheral nervous system. The differences in accumulation of the protein correlate with the apparent differences in the ability of peripheral and central axons to regenerate. The synthesis of the 37-kilodalton protein is inhibited when proper innervation or reinnervation is established.

The axon reaction of the goldfish mauthner cell and factors that influence its morphological variability.

The axon reaction of the goldfish Mauthner cell, elicited by spinal cord transection, included somatic swelling, nuclear eccentricity, chromatolysis, nuclear infolding, and a perinuclear buildup of basophilic material. The latter three changes were found most consistently and showed gradations which were ranked quantitatively. The time of onset of chromatolysis and nucleus-associated changes depended upon the distance of the wound from the Mauthner cell soma. Specifically, for Mauthner axons cut at 5, 10.5, and 20 mm distal to their somata, the approximate postoperative times of onset were 10, 20, and 40 days, respectively. Mauthner cells axotomized 42 mm distally did not display a consistent axon reaction. Cell atrophy and death were not found in cells axotomized 10.5, 20, or 42 mm from their somata up to 285 postoperative days, but were observed at the longer postoperative intervals (421 days) in neurons cut 5 mm distally and were consistently found in neurons axotomized less than 1.6 mm from their somata. The axon reactions of Mauthner cells within a pair were frequently different. This variability cannot be explained by the influence of cut site or postoperative interval and is hypothesized to result from different metabolic conditions of the individual cells.