Ultrasound-guided gradual reduction using flexion and abduction continuous traction for developmental dysplasia of the hip: a new method of treatment.

We describe our experience in the reduction of dislocation of the hip secondary to developmental dysplasia using ultrasound-guided gradual reduction using flexion and abduction continuous traction (FACT-R). During a period of 13 years we treated 208 Suzuki type B or C complete dislocations of the hip in 202 children with a mean age of four months (0 to 11). The mean follow-up was 9.1 years (five to 16). The rate of reduction was 99.0%. There were no recurrent dislocations, and the rate of avascular necrosis of the femoral head was 1.0%. The rate of secondary surgery for residual acetabular dysplasia was 19.2%, and this was significantly higher in those children in whom the initial treatment was delayed or if other previous treatments had failed (p = 0.00045). The duration of FACT-R was significantly longer in severe dislocations (p = 0.001) or if previous treatments had failed (p = 0.018). This new method of treatment is effective and safe in these difficult cases and offers outcomes comparable to or better than those of standard methods.

Septic arthritis and atopic dermatitis: 2 cases and a review of the recent literature

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Spontaneous rupture of extensor tendons at the wrist in a patient with mixed connective tissue disease.

Abstract A 54-year-old woman who had been treated for mixed connective tissue disease for 4 years developed spontaneous rupture of extensor tendons in the wrist. The patient was surgically treated by tendon reconstruction. Histopathological examination of the synovial membrane showed lymphocytic inflammatory cellular infiltration around small blood vessels. The tendon ruptures in this case were most likely caused by synovial membrane proliferation in the wrist and mechanical stress generated by the subluxated distal ulna.

[Effect of probucol on the concentration of cyclosporin A in patients with nephrotic syndrome].

The first choice of therapy for nephrotic syndrome is steroid, and cyclosporin A(CyA) or other immunosuppressants are selected for steroid resistant or recurrent cases. Nephrotic syndrome accompanies hyperlipidemia for which HMG-CoA reductase inhibitors are mainly used. On the other hand, probucol is used in cases showing inadequate effects or some adverse reactions under treatment with HMG-CoA reductase inhibitors. Recently, we experienced several cases whose blood levels of CyA were decreased to about half that before the combined use of probucol, and concomitant administrations were discontinued. Based on these cases, we considered that the use of probucol should be prescribed in patients with nephrotic syndrome accompanying hyperlipidemia giving preference to CyA treatment. In cases of unavoidable usage of probucol, CyA dose adjustments are required on the basis of frequent CyA blood level monitoring.

Sequential magnetic resonance imaging in slipped capital femoral epiphysis: assessment of preslip in the contralateral hip.

Thirty-three images using magnetic resonance imaging (MRI) in 10 patients with slipped capital femoral epiphysis were evaluated. The MRI of affected hips delineated typical widening of the physis. Sequential MRI demonstrated the process of premature closure of the physis developing from the posterior portion anteriorly. In 4 of the 10 asymptomatic contralateral hips, physeal widening was clearly observed in the center or posteromedial region of the physis on T1-weighted images. We performed prophylactic pinning for the four cases showing physeal widening on MRI, and none of the other cases developed a slip. MRI accurately documented detailed features of slips, as well as physeal changes, and may provide indicative information on prophylactic pinning for contralateral hips.

Upregulation of H(+)-peptide cotransporter PEPT2 in rat remnant kidney.

The progression of renal damage resulting from reduced nephron mass has been extensively studied in the 5/6 nephrectomized rat. However, reabsorption of small peptides and D-glucose across the renal proximal tubule in this model remains poorly understood. In this study, we examined the alterations of H(+)-peptide cotransporters (PEPT1 and PEPT2) and Na(+)-D-glucose cotransporters (SGLT1 and SGLT2) in chronic renal failure. Two weeks after surgery, H(+)-dependent [(14)C]glycylsarcosine uptake by the renal brush-border membrane vesicles isolated from 5/6 nephrectomized rats was significantly increased compared with that from sham-operated controls. Kinetic analysis revealed that the maximum velocity value for [(14)C]glycylsarcosine uptake by the high-affinity-type of peptide transporter was increased threefold by 5/6 nephrectomy, without significant changes in the apparent Michaelis-Menten constant value. Competitive PCR analyses indicated that the expression of PEPT2 mRNA was markedly increased in the remnant kidney, but PEPT1, SGLT1, and SGLT2 mRNA levels showed no significant changes. These findings indicated that the high-affinity-type H(+)-peptide cotransport activity is upregulated by 5/6 nephrectomy, accompanied by the increased expression of PEPT2. The upregulation of PEPT2 expression would result in an increase in reabsorption of small peptides and peptide-like drugs across the brush-border membranes in chronic renal failure.

Bilateral humeral lengthening in achondroplasia.

Twenty humeral lengthenings were done on 10 achondroplastic dwarfs using the Ilizarov circular fixator. There were five female and five male patients from 6 years 11 months to 17 years 8 months of age (mean, 12 years 10 months) at the time of the operation. Mean length obtained was 7.8 cm (range, 3.5 cm-10 cm). External fixation time ranged from 105 days to 368 days (mean, 221 days). Healing index averaged 30 days/cm (27 days/cm when two patients with radial nerve palsy were excluded). Two half pins in one patient required replacement. Two humeral fractures occurred, one while in the fixator and the other after removal of the apparatus. Transient radial nerve palsy developed during lengthening in two patients, and lengthening was discontinued. Symptoms of radial nerve palsy resolved completely in both patients, but one patient required an additional surgery to explore the radial nerve for persistent paresthesia of the forearm. Although preexisting loose shoulders deteriorate during lengthening and sometimes cause pain and discomfort, they always resolve spontaneously as lengthening proceeds. Bilateral humeral lengthening was very effective for improving function and overall proportion in patients with achondroplasia.

Flexor tendon rupture in the rheumatoid wrist caused by bony spurs in the carpal tunnel.

Abstract Five cases of flexor tendon rupture in surgically treated rheumatoid wrists were studied. The tendon ruptures occurred in the thumb and index finger, and the ruptures site was in the carpal tunnel in all five cases. The main cause of rupture was the formation of bony irregularities in the form of bony spurs in the carpal bones, mainly in the scaphoid, or at the volar aspect of the distal radius, as a result of rheumatoid erosion. In all five cases, tendon reconstruction and bony spur excision were conducted, and good recovery of phalangeal function was achieved. To clarify the causes of the rupture of the flexor pollicis longus in rheumatoid hands, we used three-dimensional computed tomography on 19 rheumatoid wrists without tendon rupture to investigate the presence or absence of bony spurs in the volar aspect of the scaphoid. The results showed a correlation between the frequency of scaphoid spurs and progression of bone changes as checked by radiography.

[Effect of itraconazole on digoxin clearance in patients with congestive heart failure].

We showed a digoxin-itraconazole interaction in three patients in whom digoxin serum concentrations were increased. Their electrocardiograms revealed arrhythmias such as ventricular premature contraction, atrioventricular block, and ST depression. The elimination half-life of digoxin in case 3 patient who continued itraconazole therapy was 8.4 days, which was estimated by nonlinear least squares method from the serum concentrations of digoxin versus time curve. In order to evaluate the influence of itraconazole on pharmacokinetic parameters of digoxin, we estimated digoxin clearance by the Bayesian method using the population pharmacokinetic parameters in Japanese patients. During the concomitant use of itraconazole and digoxin, the digoxin clearance in all patients decreased to 50.5 +/- 8.8% (mean +/- S.D.) of the clearance without itraconazole. When digoxin and itraconazole are used concomitantly, careful monitoring of digoxin serum concentrations is necessary. Based on our results of digoxin clearance evaluation, the dose of digoxin should be reduced to 50% of original dose after itraconazole is started, and digoxin serum concentration might be controlled at the same level before the concomitant use.

Magnetic resonance imaging of growth plate injuries: the efficacy and indications for surgical procedures.

In 23 patients with growth plate injuries, magnetic resonance imaging (MRI) studies were performed a total of 31 times to evaluate the physis which showed plain radiographic evidence of possible damage. Fourteen patients clinically showed growth arrest, and 10 patients required a Langenskiold operation. In 3 patients who underwent this operation, subsequent premature total fusion of the physis adversely affected the postoperative results. We propose that the merging shape of the arrest line with calcification of the provisional zone of the metaphysis shown by MRI indicates poor viability of the physis. MRI provided useful information on the appearance of the growth plate and changes in the metaphysis, both of which affected the prognosis and the results of the surgical procedures.

A histochemical investigation of the bone formation process by guided bone regeneration in rat jaws. Effect of PTFE membrane application periods on newly formed bone.

BACKGROUND: Guided bone regeneration (GBR) has been widely utilized for the promotion of bone augmentation in bone loss areas. However, little information has been available regarding chronological changes in newly formed bone and alterations in the nature of newly formed bone after removal of a barrier membrane. The present study attempted to establish a GBR model for rat maxillae. We also examined the effects of membrane application periods on newly formed bone and its remodeling process after removal of the membrane in this experimental model. METHODS: Thirty-five Wistar rats were divided into 2 groups: a membrane application group and a membrane removal group. The chronological changes of newly formed bone were evaluated histologically and statistically. RESULTS: At 2 weeks after the GBR procedure, bony cavities had completely filled the newly formed bone in the experimental side. In the control side, corticalization on the surface of the newly formed bone proceeded with a decrease in the bone marrow cavity, whereas the bone marrow space had enlarged by 12 weeks post-surgery in the experimental side. In the membrane removal group, the osteoblasts appeared on newly formed bone at 1 week after membrane removal. Comparatively thick compact bone had formed on the surface of the newly formed bone at 4 weeks after membrane removal, and corticalization proceeded later. CONCLUSIONS: The long-term application of a barrier membrane induces the enlargement of the bone marrow spaces. We suggest that PTFE membrane removal in adequate time promotes the corticalization and maturation of the newly formed bone by the GBR technique.

Tissue response to titanium implants in the rat maxilla: ultrastructural and histochemical observations of the bone-titanium interface.

BACKGROUND: The detailed mechanism of osseointegration, the most appropriate implant-bone interface, remains unclear in jaw tissues at the ultrastructural level in contrast to the many reports using long bones. The present study reports on tissue response to titanium-implantation on an animal model using rat maxilla. METHODS: Animals were sacrificed at 1 to 28 days post-implantation and prepared tissue specimens, freed from implants by a cryofracture technique, were processed for transmission electron microscopy and histochemistry for tartrate resistant acid phosphatase activity (TRAPase). RESULTS: Different patterns in bone formation were recognized between lateral and base areas of implant cavities. In the lateral area with narrow gaps, bone deposition took place from the pre-existing bone towards the implant after active bone resorption by osteoclasts reactive to TRAPase. However, no distinct bone formation appeared in the lateral area where the implant had been installed close to the osteotomy margin. On the other hand, new bone formation was found at the base area without any apparent bone resorption. Interestingly, mononuclear cells reactive to TRAPase, presumably preosteoclasts, frequently occurred near preosteoblasts. Osseointegration around the implants was obtained in this model by 28 days post-implantation except for the lateral area with complete contact with implants, where the thin layer remained in contact with the implant surface. CONCLUSIONS: These findings indicate that ossification proceeds at different modes around the titanium implant in rat maxilla, depending on the nature of the recipient bones and the dimension of the gap between the implant and osteotomy margin.

Preliminary traction and the use of under-thigh pillows to prevent avascular necrosis of the femoral head in Pavlik harness treatment of developmental dysplasia of the hip.

One hundred and sixty-one hips of 145 patients were treated with the Pavlik harness for developmental dysplasia of the hip. The patients were divided into two groups. Group A consisted of 65 patients (70 hips) who were treated between 1980 and 1987. The harness was applied immediately after the diagnosis. Group B consisted of 80 patients (91 hips) who were treated between 1988 and 1992. These patients received preliminary traction, and small pillows supported the lower extremities from just above the knee to the foot to prevent extreme abduction when the harness was applied. When the distance from the middle point of the proximal metaphyseal border of the femur to the Y-line (distance "a") was 8 mm or more on the initial X-ray picture, the rate of avascular necrosis in group A was 11% and that in group B was 0%; the difference was significant. However, when distance "a" was less than 8 mm, the rate of avascular necrosis in group A was 13% and that in group B was 12%, and there was no significant difference. Thus, we suggest that the Pavlik harness is indicated for developmental dysplasia of the hip in which distance "a" is 8 mm or more. Traction should precede application of the harness, and pillows placed under the thigh must be used during application.

Arrhythmic firing in dopamine neurons of rat substantia nigra evoked by activation of subthalamic neurons.

Intracellular recordings were made from dopaminergic neurons of the rat substantia nigra compacta (SNc) in in vitro slice preparations to study the synaptic influence from the subthalamic nucleus (STh). After microstimulation of STh, monosynaptic excitatory postsynaptic potentials (EPSPs) were produced in dopaminergic neurons. STh-induced EPSPs were composed of 6-cyano-7-nitroquinoxalene-2,3-dione- and 2-amino-5-phosphonovaleric acid-sensitive components. Subthreshold EPSPs evoked by STh stimulation could differentially trigger pacemaker-like slow depolarization (PLSD) and low-threshold Ca2+ spike (LTS) depending on the level of baseline membrane potentials. When a subthreshold EPSP was evoked by STh stimulation during rhythmic firing, the STh-induced EPSP could shift or elevate PLSD to a more depolarized level, resulting in generation of a spike at an earlier arrhythmic timing to restart the rhythmic firing. The interspike interval after the arrhythmic spike remained almost unchanged. In contrast, when a suprathreshold EPSP for evoking spikes was produced by STh stimulation during rhythmic firing, the STh-induced spike was just interposed between two spontaneous spikes the interspike interval of which was almost the same as those seen during the preceding rhythmic firing. This ectopically induced spike did not disturb or reset rhythmic firing. It was concluded that SNc dopaminergic neurons receive monosynaptic glutamatergic inputs from STh, and subthreshold and suprathreshold EPSPs evoked by STh stimulations can induce two types of arrhythmic firing in SNc dopaminergic neurons, similar to arrhythmic occurrences of the QRS complex seen in the electrocardiogram of the atrial and ventricular arrhythmias, respectively. The former arrhythmic firing may play a crucial role in desynchronization of dopaminergic neurons.

Effect of clarithromycin on renal excretion of digoxin: interaction with P-glycoprotein.

We present a digoxin-clarithromycin interaction in two patients in whom digoxin concentrations were unexpectedly increased. The ratio of renal digoxin clearance to creatinine clearance in one patient was lower during the concomitant administration of clarithromycin (0.64 and 0.73) than that after cessation of clarithromycin administration (1.30 +/- 0.20; mean +/- SD). Because P-glycoprotein could play an important role in the renal secretion of digoxin, we hypothesized that clarithromycin decreases renal digoxin excretion by inhibiting P-glycoprotein-mediated transport. Digoxin transport was evaluated with use of a kidney epithelial cell line, which expresses the human P-glycoprotein on the apical membrane by transfection with MDR1 complementary deoxyribonucleic acid. Clarithromycin inhibited the transcellular transport of digoxin from the basolateral to the apical side in a concentration-dependent manner and concomitantly increased the cellular accumulation of digoxin. These results suggest that clarithromycin may inhibit the P-glycoprotein-mediated tubular secretion of digoxin, and this interaction mechanism may contribute to an increase in the serum digoxin concentration.

Interaction of beta-lactam antibiotics with H+/peptide cotransporters in rat renal brush-border membranes.

Two H+/peptide cotransporters, PEPT1 and PEPT2, are expressed in the kidney, mediating the renal tubular reabsorption of oligopeptides and beta-lactam antibiotics. We examined the interactions of beta-lactam antibiotics with peptide transporters in rat renal brush-border membranes by evaluating the inhibitory potencies of the antibiotics against glycylsarcosine transport. Western blot analysis revealed that PEPT1 and PEPT2 were expressed in the renal brush-border membranes with the apparent molecular masses of 75 and 105 kDa, respectively. Using renal brush-border membrane vesicles, the uphill transport of glycylsarcosine was observed in the presence of an inward H+ gradient and an inside-negative membrane potential. Two transport systems with high affinity (Km of 50 microM) and low affinity (Km of 1.2 mM) appeared kinetically to mediate the glycylsarcosine uptake. The inhibition constants of the antibiotics for glycylsarcosine transport were more closely correlated with those in stable LLC-PK1 cells transfected with rat PEPT2 rather than PEPT1 cDNA. The beta-lactam antibiotics with an alpha-amino group showed trans-stimulation effects on the glycylsarcosine uptake, suggesting that these antibiotics and glycylsarcosine share a common peptide transporter. However, the antibiotics lacking an alpha-amino group failed to show the trans-stimulation effect. It is concluded that amino-beta-lactam antibiotics at therapeutic concentrations interact predominantly with PEPT2 localized in the brush-border membranes of rat kidney.

Functional outcomes of "floating elbow" injuries in adult patients.

OBJECTIVES: To assess elbow function, complications, and problems of floating elbow fractures in adults receiving surgical treatment. DESIGN: Retrospective clinical review. SETTING: Level I trauma center in Kanagawa, Japan. PATIENTS: Fourteen patients with fifteen floating elbow injuries, excluding one immediate amputation, seen at the Kitasato University Hospital from January 1, 1984, to April 30, 1995. INTERVENTION: All fractures were managed surgically by various methods. In ten cases, the humeral and forearm fractures were treated simultaneously with immediate fixation. In three cases, both the humeral and forearm fractures were treated with delayed fixation on Day 1, 4, or 7. In the remaining two cases, the open forearm fracture was managed with immediate fixation and the humerus fracture with delayed fixation on Day 10 or 25. MAIN OUTCOME MEASUREMENTS: All subjects underwent standardized elbow evaluations, and results were compared with an elbow score based on a 100-point scale. The parameters evaluated were pain, motion, elbow and grip strength, and function during daily activities. Complications such as infections, nonunions, malunions, and refractures were investigated. RESULTS: Mean follow-up was forty-three months (range 13 to 112 months). At final follow-up, the mean elbow function score was 79 points, with 67 percent (ten of fifteen) of the subjects having good or excellent results. The functional outcome did not correlate with the Injury Severity Score of the individual patients, the existence of open injuries or neurovascular injuries, or the timing of surgery. There were one deep infection, two nonunions of the humerus, two nonunions of the forearm, one varus deformity of the humerus, and one forearm refracture. CONCLUSION: Based on the present data, we could not clarify the factors influencing the final functional outcome after floating elbow injury. These injuries, however, potentially have many complications, such as infection or nonunion, especially when there is associated brachial plexus injury. We consider that floating elbow injuries are severe injuries and that surgical stabilization is needed; beyond that, there are no specific forms of surgical treatment to reliably guarantee excellent results.