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Biomedical subjects

N Schwarz

Publications and source records attributed to N Schwarz.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Injuries of the cervical spine in children and adolescents].

Ligamentous and osseous injuries of the cervical spine during growth are extremely rare and therapeutic principles for such lesions are ill-defined. In order to help solve some diagnostic and therapeutic problems a retrospective study of 30 children was carried out. There were 5 discoligamentous injuries, 5 fractures of the atlas, 1 fracture of the arcus C2, 8 fractures of the odontoid, and 11 vertebral body compression fractures. The injuries were caused by motor vehicle accident in 9, by diving into shallow water in 7, by falling from a height in 7, by a sports accident in 6, and by a direct trauma in 1 patient. Four children died, three of them due to concomitant brain injury. Two patients suffered permanent neurologic disability due to spinal cord trauma. Five patients underwent an operation. Conservative therapy of flexion-compression fractures of the vertebral bodies caused kyphotic deformity. Ventral interbody fusion in two patients had excellent long-term results. All odontoid fractures were treated by applying a plaster cast and healed promptly. Diagnostic problems were mainly caused by the hypermobility of the upper cervical spine.

Adolescent↗
PubMed1993

Early osteoinduction in rats is not altered by fibrin sealant.

The angiogenic and fibrogenic activities of fibrin sealant (Tisseel) suggest that it could enhance osteoinductivity during the first days after implantation. To test this hypothesis, the osteoinductivity of sealed and unsealed bone matrix gelatin was tested by implantation into rat abdominal wall muscle pouches for two to ten days. A sponge of collagen with or without fibrin sealant was used for control. Alkaline phosphatase (ALPase) was employed to quantify osteoinduction, and myeloperoxidase (MPO) was used to determine the inflammatory reaction. Plain histologic analysis of bone matrix gelatin implants at Days 2, 4, and 10 did not demonstrate any significant differences between sealed and nonsealed implants. Histologic analysis at Day 21 confirmed the osteoinductivity of the implant. The combination of bone matrix gelatin and fibrin sealant induced an early significant increase in ALPase activity, which could be interpreted as early induction of histologically undetectable osteogenesis. A simultaneous increase in the level of MPO suggested that the bone matrix gelatin/fibrin sealant-induced ALPase reaction might be caused by an inflammatory process, but neutrophil counting did not correlate to the MPO data. Morphometry, however, seems to be insufficient to assay a heterogenous histologic distribution of singular cells. It is proposed that the ALP/MPO ratio may be used as an inflammation-independent marker of osteogenesis. This study does not support the notion of an osteoinductive potency of fibrin sealant per se; however, it is clear that fibrin sealant does not impair bone matrix gelatin-dependent osteoinduction.

Abdominal Muscles↗
PubMed1992

Mood effects on attitude judgments: independent effects of mood before and after message elaboration.

This study investigated the independent effects of induced mood on the encoding of persuasive messages and on the assessment of attitude judgments. In Experiment 1, positive or negative mood was induced either before the encoding of a counterattitudinal message or before the assessment of attitude judgments. When mood was induced before message presentation, Ss in a bad mood were more persuaded by strong than by weak arguments, whereas Ss in a good mood were equally persuaded by strong and by weak arguments. When Ss encoded the message in a neutral mood, however, the advantage of strong over weak arguments was more pronounced when Ss were in a good rather than in a bad mood at the time of attitude assessment. In Experiment 2, Ss exposed to a counterattitudinal message composed of either strong or weak arguments formed either a global evaluation or a detailed representation of the message. Positive, negative, or neutral mood was then induced. Ss in a good mood were most likely and Ss in a negative mood least likely to base their reported attitudes on global evaluations.

Adult↗
PubMed1992

Osteosynthesis of irreducible fractures of the clavicle with 2.7-MM ASIF plates.

Thirty-six patients with Allman group-2 fractures of the clavicle were treated by ORIF with 2.7-mm ASIF dynamic compression plates. The indications for surgery were an open fracture in one patient, ipsilateral fractures of the arm or the ribs in five patients, bilateral clavicular fractures in one patient, and an inability to reduce the fracture in all other patients. There were no instances of deep infection. One patient suffered a refracture after plate removal; three patients developed pseudarthrosis because plates that were too short were used. The total failure rate was 12%. It is concluded that the 2.7-mm DCP is the method of choice for internal fixation of midshaft clavicular fractures and that a minimum of three screws should be placed in each fragment.

Adolescent↗
PubMed1992

[Locked rotational dislocation of the cervical spine].

There is no generally accepted treatment protocol for dislocations of single articular processes of the cervical spine. However, the data in our own series and a survey of the literature show that in this type of injury the primary diagnosis rate is low (around 50%), that closed reduction maneuvers can be neurologically hazardous, and that operative fusion prevents certain complications. Among the 20 patients treated at the authors' institution the injury was located in the lower cervical spine in all but one patients and it was caused by a high-speed traffic accident in 14 patients. Four patients had no therapy at all; the others were fused by an anterior approach in 8, a dorsal approach in 6, and a combined method in 2 patients. There was one death due to intimal tearing of a vertebral artery. Closed reduction caused a transient neurological lesion in 2 patients. In 6 patients whose dislocation was neither reduced nor fused, 3 developed chronic instability. In our new treatment protocol dislocation of a single articular process is only reduced after a diskectomy to prevent extrusion of the disc. If reduction from the anterior approach fails or if it cannot be achieved due delayed treatment, the entrapped nerve root is decompressed. Fusion of the injured segments is carried out by bone blocks and plates or hooks.

Adolescent↗
PubMed1992

[The Spiegelberg device for epidural registration of the ICP].

The Spiegelberg device is based on air-filled balloon system and was designed for epidural ICP monitoring. Zero adjustment is done automatically with the device in situ, thus avoiding zero drift. In 14 patients with mostly severe head injury (Glasgow Coma Scale score of 8 or lower in 10 patients) and 19-84 years old monitoring was carried out during treatment in the intensive care unit. ICP values were checked by repeating functional tests of the monitoring system, by serial cranial CT, and by a study of the clinical outcomes. Four patients died. There were no technical problems or infections. Clinically reliable data were obtained in 10 patients. The ICP shown was correlated with all other parameters; it was lower than would be expected in 1, and higher in 3 patients. With six simultaneous measurements with Gaeltec ICT/b, Camino subdural or an intraventricular catheter system the values were found to correlate only in 1 case. Experimental and clinical data suggest that the Spiegelberg-monitored ICP is somewhat higher than the ICP shown by other epidural systems. Clinical trials will be continued.

Adult↗
PubMed1991

Decalcified and undecalcified cancellous bone block implants do not heal diaphyseal defects in dogs.

UNLABELLED: In a previous study it has been shown that granulae of decalcified bone matrix do not induce bony healing of 8-week-old mid-diaphyseal defects in dogs. The aim of this study was to test whether osteoinduction combined with the osteoconductive mechanisms provided by the natural structure of cancellous bone blocks would yield better results. A 30-mm-long diaphyseal defect of the left ulna was created in eight adult mongrel dogs and the bone was stabilized with a plate. A Silastic spacer was inserted in the defect for 8 weeks, followed by implantation of frozen undecalcified or decalcified allogeneic cancellous bone blocks for 16 weeks. Healing was analyzed using morphologic methods. At 16 weeks after implantation all grafts had been resorbed. In the decalcified group one defect healed, while none in the other group did so. The implant material was bioassayed in nude rats for osteoinductivity, which was found to be low in decalcified matrix and not detectable in undecalcified bone. CONCLUSION: Allogeneic cancellous bone blocks, demineralized or not, have no osteoinductive capacity and no osteoconductive function that promotes healing of mid-diaphyseal bone defects in dogs.

Animals↗
PubMed1991

Injuries to the cervical spine causing vertebral artery trauma: case reports.

In four patients with lesions of the vertebral artery resulting from cervical spine injury, two were due to unilateral facet dislocation and two to fractures of the dens. There was one arterial occlusion with minor vertebrobasilar symptoms, and an arterial lesion with thrombosis causing embolic occlusion of the basilar artery with lethal outcome. In one patient a fresh fracture of the dens caused dislocation of C1/2 with reversible occlusion of the left and stenosis of the right vertebral artery, resulting in unconsciousness. In a patient with pseudarthrosis of the dens an aneurysm of the vertebral artery could be detected. Cerebellar or cerebral symptoms associated with cervical spine injury should be investigated by vertebral angiography because vertebral arterial injury may be more common than suspected and may simulate traumatic brain damage.

Adult↗
PubMed1991

Fresh autogeneic, frozen allogeneic, and decalcified allogeneic bone grafts in dogs.

In fully-grown mongrel dogs, diaphyseal ulnar defects 25 mm long were stabilised by screws and plates, and were temporarily filled with silicone rubber blocks. After eight weeks the block was replaced either by fresh autogeneic cancellous bone, allogeneic deep-frozen cancellous bone, allogeneic decalcified bone matrix, or bone matrix gelatin. After 24 weeks the implants were evaluated by radiography, histology, and measurements of new bone volume, using computer-assisted density registration on microradiographs. Only the autogeneic bone grafts led to healing in all instances. Bone regeneration in the other groups was not significantly better than in the sham group in which no graft was employed. Decalcified bone matrix proved ineffective.

Animals↗
PubMed1990

[Treatment results and indications for surgery in subtrochanteric femur fractures during growth].

A series of 29 subtrochanteric femoral fractures in children and adolescents treated during the last twenty years is presented. Primary osteosynthesis was done in five, secondary osteosynthesis in eleven patients. Ten patients were treated by an unilateral external fixator, two by a DC-plate, two by intramedullary nails, one by a Rushpin and one by cerclage wires. There were no deep infections. 13 patients were treated conservatively. Axial deviations resulted from conservative therapy in 9 of 11 patients, from osteosynthesis in one of 15 patients. One third of both series showed rotatory malalignment. Spontaneous corrections of axial deviations during growth can only be expected in small children to a small amount. In the average, operatively treated children had a positive leg length difference of one to two centimeters, whereas conservative treatment mostly resulted in equal leg lengths, but few patients showed differences from -4cm to +1 cm. Rotation and leg length seem to be more important for the clinical outcome than axial deviations of less than 20 degrees. Except in cases of severe concomitant injuries subtrochanteric fractures of the femur do not present an indication for primary osteosynthesis. If fracture reduction is not achieved by conservative means during the first four days osteosynthesis by DC-plates is recommended.

Adolescent↗
PubMed1990

[Bone replacement using demineralized allogeneic bone in animal experiments].

The implantation of bone matrix in muscle bag or trepanation defects of rats with greatest reproducibility will induce osteogenesis and defect healing. The phenomenon of osteo-induction was possible to obtain only in first steps in higher developed mammals. Investigations in nude rats have shown a clear difference in biologic reaction on the matrix of various species. The osteo-regeneration in replacement weak defect of ulnar bone in dogs showed a massive greater reactivity of autogenous spongiosa, whereas bank spongiosa and bone matrix produced not more new bone as the control. An increase of osteoinductive matrix potency is a supposition for practical use in case of severe bone defects.

Animals↗
PubMed1989

Cognitive and affective bases of opinion survey responses.

Two experiments investigated the determinants of agreement with propositions that advocated social privileges for either people in general or specific social groups. Liking for the group to which a group-specific proposition referred had a contrast effect on agreement with a related general proposition that was considered immediately after it, but had a positive influence on agreement with a general proposition that did not occur until several items later. The latter effect was eliminated by instructing Ss to base their judgments on the consequences of the policies described in the propositions. Instructions to base judgments on affective reactions to the propositions produced contrast effects of group-specific propositions on judgments of general ones regardless of whether these items were separated or together in the questionnaire.

Affect↗
PubMed1989

Dog bone less osteogenetic than rat bone. Bone-matrix transplants in nude rats.

Demineralized bone matrix and bone-matrix gelatin prepared from cortical rat bone, and from cortical and cancellous canine bone were implanted into muscle pouches of nude rats for 6 weeks. Evaluation was done by histology, histomorphometry, and determination of alkaline phosphatase. Rat matrix consistently induced new bone and high phosphatase levels. Canine matrix induced but small amounts of bone and lower phosphatase levels, with cortical matrix somewhat more inductive than cancellous matrix; demineralized cancellous bone matrix from the dog was the only material tested not showing any inductivity. Irrespective of bone type or species, gelatin had clearly higher induction capacity than demineralized bone matrix.

Alkaline Phosphatase↗
PubMed1989

The influence of fibrin sealant on demineralized bone matrix-dependent osteoinduction. A quantitative and qualitative study in rats.

Allogeneic demineralized bone matrix (DBM) and bone matrix gelatin (BMG) were implanted with or without fibrin sealant (FS) ectopically (abdominal wall) and orthotopically (7-mm trepanation defect) in 38 male Sprague-Dawley rats. Evaluation was done by descriptive histology, histomorphometry of orthotopic implants, and determination of alkaline phosphatase in ectopic implants. The observation period was 21 days with ectopic implantation and 26 days with orthotopic implantation. In all ectopic specimens, new bone developed without any qualitative difference between specimens with and without FS. The alkaline phosphatase activity did not change significantly upon addition of FS. Morphometry revealed slight differences between the groups with and without FS. The peripheral bone deposits in the BMG + FS group, was significantly larger than in the BMG group. These investigations demonstrated neither a clearly positive nor negative effect of FS on ectopic osteoinduction or BMG-dependent osteoregeneration.

Alkaline Phosphatase↗
PubMed1989

[Stability of the spine following osteosynthesis with internal fixation. Case report].

Fractures of the first and third lumbar vertebrae were primarily reduced and stabilized with a Fixateur interne (The XII-LIV) and filled with transpedicular bone grafts in a 21 years old girl. Nine months after this injury she fell from the fifth floor sustaining a flexion-distraction fracture of Th XI whereas the lumbar spine as well as the Fixateur interne remained intact. Stabilization by a Fixateur interne was carried out again. This is an example of the broad application of Fixateur interne in lower thoracic and lumbar spine traumatology and for the high degree of stability of the Fixateur system.

Adult↗
PubMed1989

[Post-traumatic hemarthrosis of the hip joint. Pathophysiolgic significance and therapeutic consequences].

A correlation between the intra-articular pressure in the hip joint and blood flow in the femoral head has been demonstrated in both experimental and clinical data. A small effusion volume (2.5 cc) is capable of causing pathological pressure values, depending upon the position of the joints, although the highest volume capacity in the hip is well over 10 cc. Relief of post-traumatic tension hemarthrosis seems to be an essential therapeutic step, as it may prevent necrosis of the femoral head.

Blood Pressure↗