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Biomedical subjects

M Brock

Publications and source records attributed to M Brock.

At least 145 records · Page 8Linked to original sources
PubMed1985

[Chymopapain allergy. Diagnostic value of a skin test before and after chemonucleolysis].

Chemonucleolysis with Chymopapain (Chymodiactin, Disease) bears the risk of unpredictable anaphylactic reactions. The rate of anaphylaxis is reported to be between 0.35 and 1.5%. Serological in vitro tests such as RAST (Radio Allergo Sorbent Test) or ChymoFAST (Fluorescent Allergo Sorbent Test) are used to determine increased specific IgE antibody titres against chymopapain in patients submitted to chemonucleolysis for lumbar disc disease. Alternatively skin prick tests have also been applied in clinical trials. A skin prick test including Discase, Chymodiactin and Solutrast 250 M, which is a radiopaque dye used for discography, has been performed in a total of 208 patients. One-hundred and seventy-seven patients were tested before, 31 patients were tested after chemonucleolysis with chymopapain. From the group tested before chemonucleolysis, 2.3-3.5% had positive skin testes. After chemonucleolysis, the overall allergy rate to chymopapain increased to 41.9%. Positive skin reactions seem to be time-dependent: Between the 3rd and 12th week after chemonucleolysis more than 70% of the patients had positive skin tests. There was no correlation between a history of previous allergy and the skin test result. Patients with positive skin tests should be excluded from chemonucleolysis. This procedure increases the safety for patients submitted to chemonucleolysis. No anaphylactic reaction has been observed hitherto in nearly 350 patients who were treated with the intradiscal injection of chymopapain following a negative skin prick test.

Adult↗
PubMed1985

Maximal regeneration distance. How far can a peripheral axon regenerate?

Peripheral nerves of the fore- and hindlimbs of 20 rats were induced to regenerate over double and triple of their original lengths through consecutive orthograde and retrograde (zigzag) anastomoses along parallel nerves of the same limb. Morphological changes were followed on longitudinal sections of the whole-mount composite nerves by several histological techniques. Regeneration regularly took place along this pathway. The regenerated axonal segments were intensively remyelinated, demonstrating the capacity of the spinal neurons to produce and maintain disproportionately long axonal processes. These observations may be relevant for reconstructive neurosurgery when very long peripheral nerve gaps have to be bridged.

Animals↗
PubMed1985

[Anesthesiologic aspects of chemonucleolysis in local anesthesia].

After treatment of herniation of a lumbar disc by injection of the enzyme chymopapain, i. e. after chemonucleolysis, anaphylactic reactions can occur in about one per cent of the cases. In order to recognise the pattern of signs associated with such reactions, well in advance, while avoiding the additional risk of general anaesthesia, some authors propagate local anaesthesia. We report on our perioperative procedure in 102 cases of chemonucleolysis under local anaesthesia. Prick's tests were carried out before surgery to exclude sensitization to the substances to be injected. In two cases only due to a positive prick test to chymopapain chemonucleolysis had to be effected with collagenase; as a matter of fact, collagenase is not known to have caused any anaphylactic reactions, but it may be responsible for local side effects, such as destruction of adjacent tissues. The patients were kept under observation by an anaesthetist during and after surgery. No anaphylactic reaction was seen. Chemonucleolysis appears to be a suitable treatment method provided it is carried out under local anaesthesia with the same precautions as applied under regional anaesthesia by the anaesthetist.

Adult↗
PubMed1985

Correlation of clinical findings, duplex carotid artery scanning and CT scanning of the brain in 54 consecutive patients with bruits over the carotid artery bifurcation.

Fifty-four patients presenting consecutively with bruits over the carotid artery bifurcation have been studied by Duplex ultrasonography of the carotid artery and CT of the brain. The patients were divided into symptomatic (transient ischaemic attacks (TIA), non-focal neurological symptoms, minor and major strokes) and asymptomatic groups. The duplex scans were subdivided into those showing a greater than 50% stenosis of the internal carotid artery and those with a less than 50% stenosis. The CT brain scans were subdivided into those showing evidence of cerebral infarction and those without. Symptomatic patients were found to be more likely to have an area of cerebral infarction than asymptomatic ones (P = 0.0086 Fisher's Exact Test). Patients with a significant stenosis (greater than 50%) of the internal carotid artery were more likely to have an ipsilateral cerebral infarction on CT than patients with a minor stenosis (less than 50% stenosis) (P = 0.028 Fisher's Exact Test). Three patients (two with TIA's and one with non-focal neurological symptoms) were found to have unsuspected cerebral infarcts on CT of the brain. These patients could theoretically be at risk following carotid endarterectomy and revascularization if the infarct were an early one. Patients with non-focal neurological symptoms and carotid bruit were more likely to have a significant stenosis than asymptomatic patients with carotid bruit (P = 0.0069 Fisher's Exact Test). Therapy should be directed at the carotid artery lesion in these cases. Duplex scanning of the carotid artery bifurcation may be combined usefully with CT brain scanning in the non-invasive investigation of patients with symptomatic extracranial carotid artery bruits.

Adult↗
PubMed1984

Ultrasonic aspiration in neurosurgery.

A short review describes the equipment of the ultrasonic aspirator CUSA, the microscopic and ultramicroscopic changes of brain tissue exposed to ultrasonic aspiration, as well as the indications and clinical experience in brain tumour operations.

Animals↗
PubMed1984

Severe local tissue lesions after chemonucleolysis with collagenase.

The authors report the case of a young female patient submitted to chemonucleolysis at L4-5 with collagenase, in whom severe tissue lesions affecting the cartilaginous end-plate, the vertebral bone, the posterior intervertebral ligament, the epidural fat, and the dura mater were verified at laminectomy, which had become necessary due to functional motor deterioration.

Adult↗
PubMed1984

Changes in intracranial pressure associated with delayed cerebral radionecrosis.

Continuous recording of intracranial pressure (ICP) from one lateral ventricle in a case of histologically proven delayed temporal radionecrosis due to previous irradiation of the pituitary gland for the treatment of an adiposity of the Cushing type has revealed the occurrence of B-waves and ramplike waves despite the absence of raised intracranial pressure. Ventriculo-atrial shunting failed to relieve the severe psychic symptomatology, which was due to direct tissue damage. These observations indicate that B-waves may have a neurogenic origin.

Brain↗
PubMed1984

Effect of intra-arterial sodium nitroprusside on intracranial pressure and cerebral autoregulation.

In cats with normal intracerebral pressure (ICP), administration of sodium nitroprusside (40 micrograms/Kg/min) through the common carotid leads to an increase of ICP, which is attributed to vasodilatation. When ICP is raised gradually to 40 mmHg by intracisternal infusion of artificial CSF prior to the application of SNP, increments of ICP due to SNP become smaller. This reduced vasodilatatory response can be attributed to either a decrease in cerebral perfusion pressure or a direct influence of intra-arterially administered SNP on the autoregulatory capacity of cerebral vessels.

Animals↗
PubMed1984

Morphological alterations of the degenerated lumbar disc following chemonucleolysis with chymopapain.

Lumbar disc tissue from 10 patients who had previously undergone chemonucleolysis without success was studied by light and scanning electron microscopy. Seven patients had a sequestrated disc; three had large protrusions. As a control, material from 10 patients subjected to disc surgery without previous chemonucleolysis was studied in the same way. The control discs revealed the characteristic signs of degeneration: alteration of the collagen, microcystic areas, and giant chondromas. Changes following chemonucleolysis were restricted exclusively to the ground substance and characterized by a marked loss of basophilia in the cartilage matrix. There was no involvement of the anulus fibrosus, cartilage plate, or bone. Following chymopapain administration, scanning electron microscopy showed a naked collagen network devoid of ground substance.

Adult↗
PubMed1984

Intradiscal pressure-volume response: a methodological contribution to chemonucleolysis. Preliminary results.

A new method is presented to verify whether a lumbar disc is degenerated prior to chemonucleolysis. This consists in rapid injection of a 0.3-ml bolus of saline into the center of the disc (through the needle employed for chemonucleolysis), under continuous recording of the intradiscal pressure changes caused by this volume load. If the intradiscal pressure falls below 600 mm Hg within 2 minutes after the injection, there is a high probability (p less than 0.001) that the disc is degenerated. This method has many advantages: it obviates additional injection of contrast medium prior to chemonucleolysis, it prevents inhibition of chymopapain by the contrast medium, it saves time, and it reduces the total amount of fluid injected during chemonucleolysis.

Adult↗
PubMed1984

Complications following chemonucleolysis with collagenase.

Lumbar disc tissue from eight patients previously submitted to unsuccessful chemonucleolysis with collagenase was studied by light and scanning electron microscopy (SEM). Similar material from eight patients subjected to primary disc surgery served as control. The control discs revealed the characteristic signs of degeneration of collagen tissue, microcystic areas, and giant chondromas. However, the anulus fibrosus and the end-plates remained intact. Following chemonucleolysis with collagenase, "digestion" of the nucleus pulposus, the anulus fibrosus, and extensive damage to the end-plates, bone, ligaments, and epidural fat were seen.

Adult↗
PubMed1984

[Case report].

Explore the source record for details and available documents.

Adolescent↗
PubMed1983

Clinical signs and evoked response alterations associated with chronic experimental cord compression.

Cortical and spinal evoked potentials were used to monitor the effect of experimental chronic cord compression in cats. An implantable compression screw made it possible to maintain the animals unrestrained. The mean compression period was 10 weeks (maximum 16.5 weeks). Compression was increased by stepwise tightening of the screw at intervals of 4 to 7 days under ketamine anesthesia. Evoked potentials were monitored before and after each compression step with repeated recordings, and were analyzed in terms of alterations in amplitude, latency, and waveform. Amplitude response curves were plotted where the amount of compression at each recording was expressed as a percentage of total compression. Changes in spinal evoked potentials occurred rather early (mean 36% of total compression), while obvious cortical evoked potential changes appeared rather late (mean 91% of total compression). Neurological alterations appeared later than alterations in spinal evoked response but prior to alterations in cortical evoked response. Thus, alterations in cortical somatosensory evoked potentials in the presence of chronic spinal compression indicate a severe degree of compression and do not seem to be of diagnostic value in the early detection of chronic spinal cord compression. It is suggested that the monitoring of spinal rather than cortical evoked responses would be more useful in locating and detecting chronic compression spinal cord damage.

Animals↗
PubMed1983

Experimental investigation on the spinal cord evoked injury potential.

Averaged somatosensory evoked potentials from the epidural space in response to sciatic nerve stimulation were recorded in bipolar and common reference mode in cats following various types of injury. An investigation was conducted on the development and properties of the spinal evoked response recorded from the center of the injury site, designated here as the "spinal cord evoked injury potential." Typically it is a two-peak monophasic positive potential, approximately 40 msec in duration, with a slight negative afterwave. With increasing distance from the site of injury, its amplitude rapidly decreases, whereas latency remains constant. The common reference recording technique resulted in an earlier and better demonstration of the evoked injury potential, especially when it was transitory or incomplete. When impairment of conduction developed gradually, the evoked injury potential developed gradually too. In serial recordings along the spinal cord axis, the transition from a normal triphasic to a monophasic evoked injury potential allowed a precise localization of the lesion. These data suggest that the diagnostic value of intraoperative spinal cord monitoring may be increased by adopting a technique that incorporates several epidural recordings with a common reference recording technique. The spinal cord evoked injury potential seems to be a more sensitive indicator of spinal cord injury than the cortical evoked potential. The findings are discussed in the light of the presently developing spinal cord monitoring techniques.

Animals↗
PubMed1982

Vascular malformations as a cause of spontaneous spinal epidural haematoma.

Seven cases of spinal epidural haematoma occurred in a series of 2,500 neurosurgical procedures. Five of these seven cases were non-traumatic in origin. In four cases the bleeding could be ascribed to various types of vascular malformations. The clinical and histological features are described, and the relevance of these findings for surgical management is discussed.

Adolescent↗