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Biomedical subjects

N Schwarz

Publications and source records attributed to N Schwarz.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Radiologic and histologic observations in central talus fractures].

In a prospective study of central fractures of the talus, radiological data (plain radiography, CT, MRI) were scrutinized in terms of correlation with histological findings (biopsy taken at time of screw removal). The study looked at nine fractures in eight patients aged 14-48 years. There was one fracture of Hawkins type I, one fracture of type II, four fractures of type III, and three corpus fractures. All were operated on within 24 h after injury; seven had screw fixation, two had adaptation with K wires. The patients were kept non-weight-bearing for 14-53 weeks. Duration of follow-up was 2 years or more in all but one patient. In the final radiograph the talus was intact in four patients, while four showed a partial avascular collapse; in one patient, a partial collapse was doubtful. Histology taken 16-52 weeks after injury showed osteocyte-free original bone in all cases, with deposition of new bone varying in extent. Hawkins sign was partially positive in six patients, positive in one, and negative in one. Decalcification as well as fracture healing can be better followed by CT than by plain radiography. MRI appeared normal in five patients, partially pathological in two, and abnormal in one. A positive Hawkins sign and normal signal behavior can be seen as prognostically favorable signs. However, in the case of a central talus fracture, even with a favorable course osteonecrosis of at least a part of the talus with gradual replacement by new bone occurred. Vascularization of the central talus seems to be disturbed more frequently than is reflected radiologically.

Adolescent↗
PubMed1996

Acetaminophen anaphylaxis with aspirin and sodium salicylate sensitivity: a case report.

BACKGROUND: Aspirin idiosyncrasy can present with bronchospasm or cutaneous reactions, but combined pulmonary and cutaneous reactions are rare. High-dose acetaminophen has been reported to provoke bronchospasm in aspirin-sensitive asthmatic patients. CASE HISTORY: We report an asthmatic adolescent female who had anaphylaxis with 650 mg acetaminophen after tolerating 325-mg doses for years. She subsequently in sequence had urticaria with aspirin and ibuprofen, and anaphylaxis with sodium salicylate. She was then challenged with acetaminophen, 325 mg orally. RESULTS: Approximately 30 minutes after acetaminophen challenge, she developed rhinoconjunctivitis, urticaria, pruritus, cough, and bronchospasm reversed with antihistamines and bronchodilators. CONCLUSIONS: Aspirin sensitivity has not frequently been described in younger age groups. This patient also had several unusual features in that she presented first with sensitivity to acetaminophen that was then followed by aspirin sensitivity. She had urticaria with both aspirin and sodium salicylate; she had combined pulmonary and cutaneous reactions to both acetaminophen and aspirin, which are rarely described; and she had anaphylaxis with low-dose acetaminophen.

Acetaminophen↗
PubMed1996

Insult, aggression, and the southern culture of honor: an "experimental ethnography".

Three experiments examined how norms characteristic of a "culture of honor" manifest themselves in the cognitions, emotions, behaviors, and physiological reactions of southern White males. Participants were University of Michigan students who grew up in the North or South. In 3 experiments they were insulted by a confederate who bumped into the participant and called him an "asshole". Compared with northerners--who were relatively unaffected by the insult--southerners were (a) more likely to think their masculine reputation was threatened, (b) more upset (as shown by a rise in cortisol levels), (c) more physiologically primed for aggression (as shown by a rise in testosterone levels), (d) more cognitively primed for aggression, and (e) more likely to engage in aggressive and dominant behavior. Findings highlight the insult-aggression cycle in cultures of honor, in which insults diminish a man's reputation and he tries to restore his status by aggressive or violent behavior.

Affect↗
PubMed1996

Mood and the use of scripts: does a happy mood really lead to mindlessness?

The authors tested whether happy moods increase, and sad moods decrease, reliance on general knowledge structures. Participants in happy, neutral, or sad moods listened to a "going-out-for-dinner" story. Happy participants made more intrusion errors in recognition than did sad participants, with neutral mood participants falling in between (Experiments 1 and 2). Happy participants outperformed sad ones when they performed a secondary task while listening to the story (Experiment 2), but only when the amount of script-inconsistent information was small (Experiment 3). This pattern of findings indicates higher reliance on general knowledge structures under happy rather than sad moods. It is incompatible with the assumption that happy moods decrease either cognitive capacity or processing motivation in general, which would predict impaired secondary-task performance.

Attention↗
PubMed1996

[Recurrent fracture of the pediatric forearm].

In a retrospective multicenter study 28 relapse fractures of the forearm in children were reviewed. The male to female ratio was 23:5. Six children were younger than 6 years, 12 were between 6 and 10 years, and 10 were between 10 and 14 years old. The primary fracture was treated by cast fixation of 3-7 weeks duration. The refracture occurred on a average 14 weeks (4-32 weeks) after the primary fracture by a simple fall (n = 14) or a fall from height (n = 4), or during school (n = 6) or leisure-time (n = 3) sporting activities. In 84% of the patients partial consolidation, i.e. incomplete healing of one cortex of one or both forearm bones, preceded the refracture. In the majority of patients this was observed after a green stick fracture due to permanent angulation. Six patients were operated upon for irreducibility of the relapse fracture; the others were treated by conservative means. In two patients a second refracture occurred. Fifteen patients were available for a 2 year result. Definitive angulation of more than 10 degrees caused a clinically relevant limitation of pro-supination in five of six patients. To prevent relapse fractures of the forearm in children, complete circular consolidation of the original fracture has to be guaranteed. It remains unclear whether this is best achieved by special plaster techniques or by converting a greenstick fracture into a complete, unstable fracture.

Adolescent↗
PubMed1996

[Isolated ossicle of the dens axis. Case reports and differential diagnosis].

Two patients with an incidental finding of isolated ossicles adjacent to the dens axis are presented. One case was thought to be based on an isolated part of the dens axis, possibly due to trauma; the second case could be a true ossiculum terminale. Such ossicles can be confused with acute fractures, initiating treatment that is not indicated.

Adolescent↗
PubMed1996

Refracture of the forearm in children.

In a retrospective study we reviewed 28 refractures of the forearm in children, which occurred at a mean of 14 weeks after conservative treatment of the primary fracture. The cause for the refracture was incomplete healing of a primary greenstick fracture in 21 cases (84%). Twenty-two recurrent fractures were treated conservatively, but two had a second refracture. Fifteen patients were followed for over two years. Definitive angulation of more than 10 degrees caused a deficit of forearm rotation. To prevent refracture of the forearm in children, complete and circular consolidation of the primary fracture must be guaranteed.

Adolescent↗
PubMed1995

Seidel interlocking nailing for healing problems in humeral shaft fractures.

In 14 patients aged 38 to 87 years humeral shaft fractures were operated on for failure of reduction, for delayed healing or for established non-union with the Seidel interlocking nail system. In five patients intraoperative technical problems were encountered. The healing rate was eight out of 12 patients. In cases of pseudarthrosis of the humeral shaft, bone grafting or local osteosynthesis in addition to medullary nailing seem advisable. The distal interlocking mechanism of the Seidel nail should be improved.

Adult↗
PubMed1995

[Post-traumatic os odontoideum].

This is a report about a 20-month-old child with acquired os odontoideum caused by a fall. Diagnosis of atlanto-axial instability was eventually made 29 months later after repeated trauma and transitory tetraparesis. Dorsal C1/2 fusion with an autogenic rib graft and plaster fixation for 8 weeks failed; an autogenic iliac bone graft plus external fixation for 12 weeks finally resulted in solid fusion.

Aged↗
PubMed1995

[Fixed atlanto-axial rotational dislocation--a rare cause of torticollis in the child].

Two patients aged 2 and 13 years old are presented, both of whom had torticollis caused by atlanto-axial rotatory subluxation. The correct diagnosis was delayed for 3 months as a result of inappropriate radiologic evaluation. In each patient increased atlanto-dental distance, anterolisthesis of the atlas, and malrotation of the atlas relative to the axis were found on a simple lateral projection. Treatment, consisting in reduction under anaesthesia and plaster fixation for 8 weeks, was successful in the smaller child, whereas redislocation occurred in the other patient. It is imperative to exclude by early radiological examination skeletal abnormality in the presence of persisting acquired torticollis in children.

Atlanto-Axial Joint↗
PubMed1995

Repair of complete acromioclavicular separations using the acromioclavicular-hook plate.

Complete Tossy III acromioclavicular separations in 21 male patients (according to the Rockwood classification: 7 Type III and 14 Type V lesions) with a mean age of 31 years were treated by surgical repair with the acromicroclavicular-hook plate within a period of 6 years. The population consisted of 18 patients with acute injuries and 3 with old injuries. Six patients experienced infections and delayed wound healing; osteitis did not occur. In 1 case, delayed wound healing was combined with dislocation of the hook. Bending of the implant occurred in another patient. Sixteen patients underwent clinical and radiographic followup at a mean of 38 months. Four patients who had no complications and free mobility of the shoulder joint at the end of treatment after removal of the implant did not appear for followup. One patient died of a malignant brain tumor. According to a modified evaluation system by Poigenfürst et al, clinical and radiographic findings showed 8 excellent, 7 good, and 1 poor result. A secondary widening of the hook hole in the acromion was seen in 13 patients; this was related to the large range of motion of the acromioclavicular joint. Calcifications and ossifications in the coracoclavicular ligaments, diastases in the acromioclavicular joint, and redislocations were not significantly different when this method was compared with other surgical techniques as reported in the literature. Use of the acromioclavicular-hook plate permits retention in the transverse plane without impairing the joint itself, but the technique is challenging.

Acromioclavicular Joint↗
PubMed1994

Post-traumatic cervical kyphosis in children cannot be prevented by non-operative methods.

Eleven children with a vertebral body flexion-compression fracture of the lower cervical spine were reviewed. Eight were treated non-operatively, two had a ventral interbody fusion and one a dorsal fusion. Follow-up time was 1 month to 12 years (mean 55 months). Following non-operative therapy six had a kyphotic deformity of more than 10 degrees at the last follow-up. Kyphosis cannot be prevented or cured by non-operative methods.

Adolescent↗
PubMed1994

Biocompatibility of xenogeneic bone, commercially available coral, a bioceramic and tissue sealant for human osteoblasts.

The drawbacks of freshly harvested autologous bone have resulted in the search for an alternative, capable of supporting osteogenic cell growth. This capability was examined in potential bone graft materials by culturing human osteoblasts on each material. Test materials included rat bone, Surgibone, Ostilit, Biocoral and Tisseel. After 3 days osteoblasts had adhered to all materials, except Ostilit. With increasing time the cells multiplied on the materials, to varying extents. Cell affinity was greatest for rat bone and Tisseel. Fewer cells attached to Biocoral and Surgibone. Thus all the materials, with the exception of Ostilit, were biocompatible for human osteoblasts.

Animals↗
PubMed1994

[2 years results of conservative therapy of unstable fractures of the pelvic ring in children].

Unstable fractures of the pelvic ring in children are usually treated conservatively. The results of this therapy were evaluated retrospectively in 17 children who had been under 13 years old at the time of injury. All but 4 of the children had additional injuries. The pelvic fracture had a rotational instability in 9 patients and was vertically unstable in 8 patients. The follow-up period was 2-25 years. Clinical results were good provided that there was a good radiological result with only minimal asymmetry of the pelvic ring or none at all. Functional leg length differences and scoliotic deformation of the lumbar spine due to traumatic and/or growth-related asymmetry of the pelvis caused chronic low back pain in 5 of 8 patients. Only fracture healing in a near-anatomical position can ensure good clinical results in pelvic fractures in children. Considering the results presented here, operative reduction has to be recommended when reduction cannot be achieved by conservative means. However, there is no proof that open reduction and internal fixation provide better results than conservative therapy in unstable pelvic ring fractures in children.

Adolescent↗
PubMed1993

Color-coded Duplex sonography of vertebral arteries. 11 cases of blunt cervical spine injury.

In 11 patients with locked cervical spine facets after blunt injury, the patency of the vertebral arteries was evaluated by color-coded Duplex sonography (CCDS) up to 11 years after the accident. In 7 patients the dislocations had been reduced, 2 had been treated conservatively, and 9 had been fused. In 9 patients (3 of them with persistent locking) the mean systolic peak flow velocity was 55 cm/sec and the vessel diameter was 0.35 cm. Only 2 patients had an abnormal CCDS. In 1 with persistent locking the ipsilateral vertebral artery was occluded, and in the other flow signals were abnormal and the vessel diameter was smaller than on the contralateral side. The high coincidence of vertebral artery occlusions and locked dislocations, as well as fracture dislocations reported by others, was not confirmed in our series.

Adolescent↗
PubMed1993

The role of fibrin sealant in osteoinduction.

Mesenchymal cell stimulation and angiotropic effects suggest a fibrin sealant-mediated enhancement of osteogenesis. For its glueing capacity fibrin sealant is also regularly used in bone surgery. However, its influence on osteoregeneration is debatable. The effect of fibrin sealant on bone matrix gelatin dependent ectopic and orthotopic osteoinduction in rats was studied. Neither biochemical nor histologic parameters revealed a direct influence of fibrin sealant on any osteoinductive process.

Animals↗
PubMed1993

[Unilateral locking of cervical facet joints. Frequency and value of roentgenologic signs].

Unilateral locking of cervical facet joints is often misdiagnosed and inadequately treated, because it is not readily detected on plain radiographs. Primary radiographs of 17 patients were analysed to evaluate radiographical signs with reference to frequency and significance. Direct signs of locking were present in no more than 53% of cases. Of these, an abrupt change in laminar space width, seen in 88.2%, proved to be the most reliable sign. Displacement of the spinous processes above and below the lesion was found in the same percentage of cases, but it carries less diagnostic weight. While present in all cases, anterolisthesis is only diagnostic if additional oblique views show evidence of lateralized cervical anterolisthesis. Clearly less reliable indirect signs included: the bow tie sign (29.4%), dehiscence of the spinous processes (23.5%), differences in the sagittal diameters of the vertebral bodies above and below the lesion (35.2%), double facet contour (47%) and tilting of the cranial segment of the cervical spine away from the locked facets (58.8%). Abnormalities of disc shape were not seen on a.-p. projections. Those detectable in axial views are irrelevant to locking, as are empty facets. If more than one indirect sign is present and if unilateral locking is suspected but cannot be established unequivocally even on additional oblique views, computed tomography is indicated, because reduction continues to be the first step in the management of fresh injuries.

Adolescent↗