PubMed Health⌕ Search

Biomedical subjects

S L Weinstein

Publications and source records attributed to S L Weinstein.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intra-articular benign osteoblastoma of the acetabulum: a case report.

The acetabulum is an unusual location for benign osteoblastoma, usually seen in adolescents and young adults. This article reports a case of an intra-articularly expanding benign osteoblastoma of the acetabulum in a 6-year-old boy. The diagnostic and surgical features of the disease in this unusual location at this young age are discussed. Excisional biopsy and curettage of the lesion followed by bone grafting resulted in healing of the acetabular lesion without acetabular dysplasia, but with a resultant coxa magna.

Acetabulum↗
PubMed1998

Atypical congenital kyphosis. Report of two cases with long-term follow-up.

We describe two patients with an atypical congenital kyphosis in which a hypoplastic lumbar vertebral body lay in the spinal canal because of short pedicles. There were no defects in the posterior elements, or any apparent instability of the facet joints. Both patients were treated successfully by anterior fusion to the levels immediately above and below the affected vertebra, and posterior fusion which extended one level more both proximally and distally. This gave progressive correction of the kyphotic deformity by allowing some continued anterior growth at the levels which had been fused posteriorly.

Humans↗
PubMed1997

Transfusion management in pediatric and adolescent scoliosis surgery. Efficacy of autologous blood.

STUDY DESIGN: A retrospective review of consecutive pediatric and adolescent patients who required posterior spinal fusion to correct scoliosis. OBJECTIVES: To 1) measure the participation of pediatric patients in predeposit programs for autologous and directed blood donation 2) to assess the success of autologous predonation in preventing allogeneic blood use, 3) to determine whether transfusion indications differed between patients who received allogeneic blood and those who received autologous blood, and 4) to assess factors that predict transfusion requirements during scoliosis surgery. SUMMARY OF BACKGROUND DATA: Authors of recent studies in adults have questioned whether transfusion of autologous blood is a cost-effective therapy when compared with the less-expensive alternative--transfusion of allogeneic blood. In children, the efficacy of autologous blood has not been assessed in a large population of surgical patients. In adults, the frequency of patient participation, the success of autologous donors in avoiding allogeneic transfusion, and the proportion of collected autologous units used during the perioperative period are measures used to establish the efficacy of autologous predonation programs. METHODS: Hospital and clinic records for each patient who underwent posterior spinal fusion from September 1, 1989 through September 1, 1994 were reviewed. Blood bank consultation, autologous donation records, anesthesia records, surgical reports, and hospital records were reviewed. Seventy percent of patients (164 of 243) participated in autologous donation. RESULTS: More than 90% of autologous donors successfully avoided receiving allogeneic blood. Patients with idiopathic scoliosis (n = 168) were more likely to participate in autologous donation (n = 144) and to avoid allogeneic blood (n = 135). Patients with neurologic causes of scoliosis more commonly used allogeneic or directed donation (56 of 75 patients). Nineteen patients with neuromuscular causes of scoliosis participated in autologous donation, but more than one half of this group (10 of 19 patients) required allogeneic blood in addition to autologous units. CONCLUSIONS: Using measures of efficacy similar to those reported in studies of adults, autologous blood was found to be more effective in meeting the transfusion needs of pediatric patients who required posterior spinal fusion than in meeting those needs in adult surgical patients in previous studies.

Adolescent↗
PubMed1997

Spine update. The management of scoliosis in neurofibromatosis.

When evaluating patients with neurofibromatosis and scoliosis, a careful search for the evidence of dystrophic changes should done, because prognosis and management depend highly on the presence of these changes. Preoperative imaging studies including computed tomography or magnetic resonance imaging are recommended, especially in cases of dystrophic scoliosis, to detect unrecognized intraspinal lesions. The radiographic findings and the response to treatment in patients with nondystrophic scoliosis are similar to those in patients with idiopathic scoliosis, and the same decision-making process for idiopathic scoliosis is applicable. Careful follow-up evaluation is mandatory, however, because of the tendency for extraordinary progression to occur with growth. Brace treatment of the short, angulated, dystrophic curves is ineffective; early and aggressive surgical intervention is strongly recommended. In most cases, dystrophic curvatures are best treated with combined anterior and posterior spinal arthrodesis. The fusion area should be generous, and the entire structural area of the deformity both anteriorly and posteriorly should be fused.

Adolescent↗
PubMed1997

Delayed postoperative paraparesis in scoliosis surgery. A case report.

STUDY DESIGN: A case report is presented of an unusual complication of scoliosis surgery that, to the authors' knowledge, has never been reported in the literature. OBJECTIVE: Neurologic complications can occur after an uneventful posterior spinal instrumentation and fusion for scoliosis. Careful observation during the post-operative period is crucial for early detection of impending neurologic deficit. SUMMARY OF BACKGROUND DATA: Nerve compression of the cauda equina has been reported as a complication of different types of surgery in the lumbar spine, but an ascending paraparesis has never been described as a complication of scoliosis surgery. METHODS: A 12-year-old boy with a right thoracic scoliosis measuring 68 degrees and a 72 degrees left lumbar curve underwent Cotrel-Dubousset instrumentation and fusion from T5 to L4. Spinal cord monitoring with somatosensory evoked potentials and motor action potential were recorded and stable through out the entire procedure. Thirty hours later, a rapidly progressive ascending para-paresis developed that required urgent decompression. RESULTS: This patient underwent urgent decompression and removal of the Cotrel-Dubousset instrumentation. After surgery, the clinical picture improved gradually, and at 2-month follow-up he had regained normal strength in his lower limbs except for a grade 4 left extensor hallucis longus. By 4 months postdecompression, he had made a total recovery. CONCLUSIONS: Although clinical examination may be difficult to perform in patients who are unconscious, on large doses of narcotic drugs, or mentally retarded, careful observation during the postoperative period and awareness of this complication can allow early detection of impending reversible neurologic deficit and provision of appropriate treatment.

Child↗
PubMed1997

All-D-enantiomers of beta-amyloid exhibit similar biological properties to all-L-beta-amyloids.

The amyloidogenic peptide beta-amyloid has previously been shown to bind to neurons in the form of fibrillar clusters on the cell surface, which induces neurodegeneration and activates a program of cell death characteristic of apoptosis. To further investigate the mechanism of Abeta neurotoxicity, we synthesized the all-D- and all-L-stereoisomers of the neurotoxic truncated form of Abeta (Abeta25-35) and the full-length peptide (Abeta1-42) and compared their physical and biological properties. We report that the purified peptides exhibit nearly identical structural and assembly characteristics as assessed by high performance liquid chromatography, electron microscopy, circular dichroism, and sedimentation analysis. In addition, both enantiomers induce similar levels of toxicity in cultured hippocampal neurons. These data suggest that the neurotoxic actions of Abeta result not from stereoisomer-specific ligand-receptor interactions but rather from Abeta cellular interactions in which fibril features of the amyloidogenic peptide are a critical feature. The promiscuous nature of these beta-sheet-containing fibrils suggests that the accumulation of amyloidogenic peptides in vivo as extracellular deposits represents a site of bioactive peptides with the ability to provide inappropriate signals to cells leading to cellular degeneration and disease.

Amyloid beta-Peptides↗
PubMed1997

Traction in developmental dislocation of the hip. Is its use justified?

Traction has been used for decades in the treatment of developmental dislocation of the hip. Traction is advocated to facilitate closed reduction and to decrease the need for open reduction. The use of prereduction traction also is advocated to decrease the incidence of proximal femoral growth disturbance (aseptic necrosis). Recently, several studies have called into question this widely accepted adjunct in the treatment of developmental dislocation of the hip. A critical look was taken at the use of traction in the treatment of developmental dislocation of the hip and whether its use can be justified by the existing medical literature was ascertained. Although there are several impressive reports of the positive effects of traction in developmental dislocation of the hip, there are no clinical or experimental studies on the direct effect of traction. There are also no well controlled studies to analyze the effect of traction as a single variable. Thus, it cannot be proven that traction alters the outcome of developmental dislocation of the hip treatment, and hence, there is only anecdotal basis for its use in the treatment of developmental dislocation of the hip.

Femur Head Necrosis↗
PubMed1997

Long-term outcome after open reduction through an anteromedial approach for congenital dislocation of the hip.

We reviewed the long-term outcome of open reduction of ninety-three congenitally dislocated hips (in seventy-six children) through an anteromedial approach. The average age of the patients was fourteen months (range, two to fifty months) at the time of the reduction and eleven years (range, four to twenty-three years) at the time of the most recent follow-up evaluation. At the most recent follow-up evaluation, sixty-six hips (71 per cent) had an excellent or good result, twenty-four (26 per cent) had a fair result, and three (3 per cent) had a poor result, according to the Severin classification system. An inverted neolimbus at the time of the operation and postoperative growth disturbance of the femoral head were associated with a poor roentgenographic result. According to the classification of Bucholz and Ogden, twenty-two hips (24 per cent) had type-II avascular necrosis, thirteen hips (14 per cent) had type-III, three (3 per cent) had type-IV, two (2 per cent) had non-classifiable lesions, and fifty-three (57 per cent) did not have avascular necrosis. A high hip dislocation and an operation after the age of twenty-four months were associated with a higher rate of growth disturbances of the femoral head. With the numbers available for study, we did not find any association between short-term preoperative traction, ligation of the medial circumflex vessel, or the type of neolimbus and the prevalence of growth disturbances. Two hips redislocated postoperatively, and seven had transient stiffness. We consider the anteromedial approach to be useful in the management of patients with congenital dislocation of the hip who are twenty-four months old or less. The advantages of this approach include direct access to the obstacles to reduction, avoidance of damage of the iliac apophysis and the abductor muscles, minimum blood loss, the need for only a single operative session for treatment of both hips, and a cosmetically acceptable scar. The prevalence of type-II growth disturbances of the femoral head was higher than had been expected, emphasizing the need for additional investigation.

Acetabulum↗
PubMed1997

Natural history and treatment outcomes of childhood hip disorders.

Normal hip joint growth and development occur as a result of a genetically determined balance of growth of the acetabular and triradiate cartilages and the presence of a well located centered spheric femoral head. The majority of acetabular development is determined by age 8 years. This is a watershed age for prognosis in many pediatric hip disorders. Hip joint growth and development and how these are affected by the disease process and treatment interventions profoundly affect outcome. Outcomes of these disease processes (congenital hip dislocation and dysplasia, Legg-Calvé-Perthes disease and slipped capital femoral epiphysis), is multifactorial but profoundly influenced by the age at the disease onset (birth to the adolescent growth spurt), and the effects of treatment on the relationship between femoral head and acetabular development. The natural history of many of these childhood hip disorders is the development of degenerative joint disease. Degenerative joint disease and clinical disability may develop in these conditions despite standard up to date treatment interventions. In most of the hip diseases discussed, patients usually do well clinically for many years regardless of treatment.

Adolescent↗
PubMed1996

Activation of multiple proline-directed kinases by bacterial lipopolysaccharide in murine macrophages.

Bacterial LPS stimulation of murine macrophages leads to increased tyrosine phosphorylation and activation of the 42- and 44-kDa mitogen-activated protein kinases (MAPK) and the activation of stress-activated protein kinases (SAPK)/c-Jun N-terminal kinase (JNK) and p38, related to the high osmolarity glycerol protein kinase in Saccharomyces cerevisiae (HOG1). LPS caused a rapid increase (10 min) in phosphotransferase activity toward myelin basic protein (MBP), a polypeptide that encompassed the first 169 residues of c-Jun fused to gluthathione S-transferase (GST-c-Jun (1-169)) and 27-kDa heat shock protein (hsp27). MonoQ fractionation of cell extracts resolved phosphotransferase activity peaks toward MBP, GST-c-Jun (1-169), and hsp27, which contained MAPK, SAPK/JNK, and MAPKAPK2, respectively, as indicated by immunoblotting data. In RAW 264.7 macrophages, LPS stimulation of MAPKAPK2, a substrate of p38 HOG1 and MAPK, appeared to occur predominantly via p38 HOG1 and not the MAPK. PMA, which activated the MAPK as potently as LPS, did not strongly activate MAPKAPK2, as assessed by hsp27 phosphorylation. Consistent with p38 HOG1-mediating LPS activation of MAPKAPK2, treatment with LPS, but not PMA, increased the tyrosine phosphorylation of p38 HOG1, a modification known to elevate the enzymatic capacity of this kinase. In LPS-treated cells, the activity of SAPK/JNK was increased 5- to 10-fold, as measured by precipitating SAPK/JNK with Abs or immobilized GST-c-Jun and performing an in vitro kinase assay. In addition, the kinases thought to be upstream of SAPK/JNK, SAPK/ERK kinase 1 (SEK1), and MAPK/ERK kinase kinase 1 (MEKK1), were activated following LPS, but not PMA, exposure (5-fold and 2.5-fold, respectively.

Amino Acid Sequence↗
PubMed1996

Activation of c-Jun N-terminal kinase in bacterial lipopolysaccharide-stimulated macrophages.

Activation of macrophages by bacterial lipopolysaccharide (LPS) induces transcription of genes that encode for proinflammatory regulators of the immune response. Previous work has suggested that activation of the transcription factor activator protein 1 (AP-1) is one LPS-induced event that mediates this response. Consistent with this notion, we found that LPS stimulated AP-1-mediated transcription of a transfected reporter gene in the murine macrophage cell line RAW 264.7. As AP-1 activity is regulated in part by activation of the c-Jun N-terminal kinase (JNK), which phosphorylates and subsequently increases the transcriptional activity of c-Jun, we examined whether LPS treatment of macrophages resulted in activation of this kinase. LPS treatment of RAW 264.7 cells, murine bone marrow-derived macrophages, and the human monocyte cell line THP-1 resulted in rapid activation of the p46 and p54 isoforms of JNK. Treatment with wild-type and rough mutant forms of LPS and synthetic lipid A resulted in JNK activation, while pretreatment with the tyrosine kinase inhibitor herbimycin A inhibited this response. Binding of LPS-LPS binding protein (LBP) complexes to CD14, a surface receptor that mediates many LPS responses, was found to be crucial, as pretreatment of THP-1 cells with the monoclonal antibody 60b, which blocks this binding, inhibited JNK activation. These results suggest that LPS activation of JNK in monocyte/macrophage cells is a CD14- and protein tyrosine phosphorylation-dependent event that may mediate the early activation of AP-1 in regulating LPS-triggered gene induction.

Animals↗
PubMed1996

Use of the Milwaukee brace for progressive idiopathic scoliosis.

One hundred and two (92 per cent) of 111 immature patients in whom idiopathic scoliosis had been treated with a Milwaukee brace were followed to determine the effectiveness of the brace in preventing progression of the scoliosis. The average time from cessation of bracing until the latest radiographs were made for the patients who were managed non-operatively was six years and four months. The average progression of the curve, from the time of initial bracing until use of the brace was stopped, in the eighty-eight patients who were included in the statistical analysis was 4 degrees. The curve continued to progress an average of 5 degrees after use of the brace was stopped in the patients who did not have an arthrodesis. Forty-two patients (48 percent) had more than 5 degrees of progression at the time that use of the brace was stopped. Thirty-seven patients (42 per cent) had an operation or a curve of sufficient magnitude to warrant operative intervention. The maximum correction of the Cobb angle in the brace had prognostic importance for progression of the curve. The patients in whom the curve did not progress or who did not need operative intervention had had an average correction of 20 per cent, while the patients who had a failure had had an average correction of 8 per cent. The patients who eventually had the indications for an arthrodesis were on the average, one year younger (eleven years and none months) and had a curve of a larger magnitude at the time of bracing than the patients who did not need an arthrodesis. The findings of this study do not agree with previously reported favorable results with bracing and raise questions about whether the natural history of progressive idiopathic scoliosis is truly altered by use of the Milwaukee brace.

Adolescent↗
PubMed1996

The teardrop in congenital dislocation of the hip diagnosed late. A quantitative study.

We retrospectively reviewed the radiographs of the pelvis and hips of forty-five patients who had unilateral congenital dislocation of the hip treated with closed reduction and application of a cast without subsequent operations. The radiographs were made at the time of the initial diagnosis, two years after the reduction, when the child was ten years old, and at skeletal maturity. The width, shape, and type of the teardrop; the thickness of the acetabular floor; the acetabular index; the center-edge angle; the articulotrochanteric distance; and the Severin class at maturity were measured in the dislocated and contralateral, normal hips. At the time of the initial diagnosis, a well defined teardrop was seen in thirty-six (80 per cent) of the normal hips and in seven (16 per cent) of the dislocated hips. There was no difference in the width of the teardrop in the seven dislocated hips compared with that in the normal hips, although the v-shaped and crossed types of teardrops were more frequent in the dislocated hips. The v shape was not observed in the normal hips but was seen in sixteen dislocated hips two years after the reduction and in twelve dislocated hips when the children were ten years old. The superior and inferior widths of the teardrop of the dislocated hips were significantly greater than those of the normal hips (p < 0.001 and p < 0.05, respectively) when the children were ten years old. The hips with residual acetabular dysplasia had a v-shaped teardrop, widening of the superior width of the teardrop, and thickening of the acetabular floor. These hips, which were usually Severin class IV at the time of skeletal maturity, had a poor prognosis in adult life.

Acetabulum↗
PubMed1996

Natural history of untreated chronic slipped capital femoral epiphysis.

From 1915 to 1952, 31 hips in 28 patients with slipped capital femoral epiphysis were observed without interventional treatment at the University of Iowa Department of Orthopaedic Surgery. A slip was considered chronic if the symptoms had been present for 3 weeks or more. The severity of the slip was determined by radiographs. Assessment included Iowa Hip Rating and grading of radiographic degenerative changes. The mean duration of patient followup from the onset of symptoms was 41 years. The mean patient age was 54 years old at review, and 13 years old at onset of symptoms. Degenerative arthritis developed in hips with displaced slipped capital femoral epiphysis. Untreated slipped capital femoral epiphysis can progress to a severe degree. The natural history of chronic slipped capital femoral epiphysis is favorable provided that displacement is minimal and remains so.

Adolescent↗
PubMed1995

Chronic stress tolerance levels for human articular cartilage: two nonuniform contact models applied to long-term follow-up of CDH.

Two computer models of nonuniform contact stress on the articular surface of the human hip were used to study the relationship between chronically excessive articular cartilage contact stress and long-term clinical outcome in a series of patients with congenital dislocation of the hip (CDH). The analyzed database consisted of 409 stylus digitized radiographs from 83 patients with unilateral CDH, who had been treated by closed reduction, and whose average follow-up time was 29.2 y. The first model (nonuniform Legal) involved a three-dimensional contact stress distribution function whose pole was coincident with the resultant force acting through the hip, and which acted over a contact area whose borders were determined soley by bony landmarks. In the second model (Brinckmann), the direction of the pole of the contact stress distribution function was initially unknown; one border of the contact region was determined by radiographic landmarks, while the other border depended upon the pole of the iteratively determined contact stress distribution function. In both models, the contact stress distributions were converted to area engagement histograms, corresponding to the fractional areas of cartilage experiencing specific ranges of stress (0.5 MPa increments). These histograms were integrated over time to calculate a cumulative contact stress overdose, which was then compared to clinical outcome. Reasonable correlations (Spearman rho = 0.63-0.66) with patient outcomes were obtained for optimally chosen damage thresholds, although these thresholds were appreciably different (2.0 versus 4.5 MPa) due to the respective modelling assumptions.

Biomechanical Phenomena↗