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Biomedical subjects

H Wassmann

Publications and source records attributed to H Wassmann.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Effects of nimodipine in experimental permanent focal cerebral ischemia].

In a controlled double blind experiment the influence of a continuous i.v. infusion of Nimodipine (1 microgram kg-1 min-1) upon infarct size, histopathology and neurological outcome in rats with permanent middle cerebral artery (MCA) occlusion was examined. The infusion was started 20 min. before the induction of ischemia and continued 4 hours thereafter. The nimodipine treated animals were subdivided into hypotensive (MABP lower than 85 mmHG for more than 5 minutes after arterial occlusion) and normotensive groups. Infarction size, documented by TTC, H&E and Nissl staining was significantly smaller (p less than 0.001) in nimodipine normtonic rats than the lesions in placebo and saline treated rats, as well as compared with hypotonic nimodipine animals (largest infarction). These differences were found to be entirely at the expense of the cortical (frontoparietal) component of the lesion, suggesting "penumbra" action of the drug. Moreover, nimodipine normotonic rats displayed lower cortical neuronal injury in the periinfarct zone. These findings were corroborated by corresponding better neurological scores. Our results indicate that nimodipine is effective in reducing focal cerebral ischemia, provided the MABP is maintained higher than 85 mmHg.

Animals↗
PubMed1991

Barbiturates in severe head injuries?

Possible mechanisms for the therapeutic effects of barbituric acid derivatives in severe head injuries have been discussed for half a century. In the following, a survey of the literature, and a discussion of three controlled clinical studies available until now is presented. A proven effect in terms of a beneficial long-term outcome for all injured patients has not been established. On the other hand there might be a subgroup of patients with an intact CO2 reactivity of the brain vessels who may profit from barbiturates administered after head trauma.

Barbiturates↗
PubMed1991

Effect of nimodipine in treatment of experimental focal cerebral ischaemia.

Despite the voluminous current literature the potential of nimodipine to modify the outcome in experimental cerebral ischaemia remains a controversial matter. The authors have evaluated in controlled double blind experiments the influence of a continuous i.v. infusion of the drug (1 microgram kg-1 min-1) upon infarct size, histopathology and neurological outcome in rats with permanent middle cerebral artery (MCA) occlusion. The infusion was started 20 min before induction of ischaemia and continued 4 hours thereafter. The nimodipine treated animals were subdivided into hypotensive (MABP lower than 85 mmHg for more than 5 min after arterial occlusion) and normotensive groups. Infarction size, documented by TTC, H&E and Nissl staining was significantly smaller (p less than 0.001) in nimodipine normotonic rats than the lesions in placebo and saline treated rats, as well compared with hypotonic nimodipine animals (largest infarction). These differences were found to be entirely at the expense of the cortical (frontoparietal) component of the lesion, suggesting 'penumbra' action of the drug. Moreover, nimodipine normotonic rats displayed lower cortical neuronal injury in the periinfarct zone. These findings were corroborated by corresponding better neurological scores. Our results indicate that nimodipine is effective in reducing focal cerebral ischaemia, provided the MABP is maintained higher than 85 mmHg.

Animals↗
PubMed1991

Lack of effect of PN 200-110 on neuronal injury and neurological outcome in middle cerebral artery-occluded rats.

We evaluated the influence of a continuous intravenous infusion of 0.24 mg/kg PN 200-110 started 20 minutes before the induction of ischemia and continued for 2 hours on infarct size, histopathology, and neurological outcome in middle cerebral artery-occluded rats treated with PN 200-110 (n = 8), placebo (n = 7), or saline (n = 8). Neurological examination was performed 24 hours after occlusion. We quantified infarct size by 2,3,5-triphenyl-tetrazolium chloride, hematoxylin and eosin, and Nissl staining and by computerized analysis of tracings of the infarcted areas and evaluated neuronal injury at the infarct periphery. The different types of ischemic cell damage were quantified by direct visual counting. We found no differences among saline-, placebo-, and PN 200-110-treated rats regarding infarct size, amount of neuronal alteration, and neurological outcome. Our results indicate the lack of a significant protective effect of this drug in experimental focal ischemia.

Animals↗
PubMed1988

Angiolipoma of the spinal cord. Magnetic resonance imaging and microsurgical management.

Radiologic diagnosis of intramedullary lipomas has been unreliable for a long time and many of these tumors have not been recognized. The introduction of computed tomography, and lately of magnetic resonance imaging, has led to great progress in the accurate identification of spinal cord tumors as well as in the recognition of type specificity of these lesions. An evaluation of the diagnostic value of magnetic resonance imaging and microsurgical technique for the optimal therapeutic outcome is discussed.

Adult↗
PubMed1988

Pseudomeningocele of the lumbar spine.

A patient with a lumbar pseudomeningocele after intervertebral disc surgery is reported and the findings of computed tomography and magnetic resonance imaging are described.

Adult↗
PubMed1987

Diagnosis of neurinoma in the region of the jugular foramen--a case report.

Neurinomas in the region of the jugular foramen are extremely rare, are difficult to diagnose before surgery, and have seldom been described in the literature. The typical jugular foramen syndromes (Collet-Sicard syndrome, Vernet's paralysis) may be caused by many various disorders. The diagnostic problems are illustrated using one of our cases as an example. The differential diagnosis was made before surgery using currently available radiologic techniques. The tentative diagnosis "neurinoma of the hypoglossal nerve" was confirmed intraoperatively and histologically.

Cerebral Angiography↗
PubMed1987

Tissue pO2 of human brain cortex--method, basic results and effects of pentoxifylline.

A polarographic multiwire surface electrode was used for measurement of local oxygen partial pressure (pO2) on human brain cortex during neurosurgical operations. The two major problems encountered in this application of the electrode involved sterility of the equipment and mounting of the electrode. The described method of sterilization does not alter the electrical properties of the electrode. A special mount was designed to allow free three-dimensional placement of the electrode without exerting pressure on the cortex. Basic results of this technique demonstrated that it is possible to distinguish different pO2 distribution patterns displayed in pO2 histograms for various types of brain tumors and edematous brain tissue. In patients with arteriovenous malformations (AVMs) of the brain, an increase of tissue pO2 in cortical areas adjacent to the AVM was the result of extirpation of the lesion. The effect of intravenously administered pentoxifylline was studied during extraintracranial bypass operations in patients with cerebrovascular disease. In 7 patients a consistent shift of the pO2 histograms to the right, i.e., to higher pO2 values, could be demonstrated. Mean pO2 values increased statistically significantly by 16 +/- 7 mmHg as early as ten minutes after infusion of pentoxifylline. The rapid improvement of tissue oxygenation of human brain cortex is thought to be the result of an improvement of microcirculation, for other parameters influencing tissue pO2 showed no significant alterations if any.

Arteries↗
PubMed1986

'Open angioplasty' in carotid artery obstructions.

A new method has been introduced for the treatment of highly located or long-segment stenoses or obstructions of the internal carotid artery not accessible by conventional carotid-endarterectomy. Following conventional carotid-endarterectomy a balloon catheter is passed through the incised carotid artery as far as the stenosis and then inflated several times. Possibly dislodged plaque material can be washed out by the retrograde blood stream. The results in 30 cases, with angiopraphic, Doppler sonographic and neurologic follow-up examinations, are reported. It was possible to achieve a distinct additional cerebral blood supply through the recanalized internal carotid artery by this method, without a severe complication rate.

Carotid Arteries↗
PubMed1986

[Psychometric studies of cerebral performance before and following extra-intracranial bypass operations].

34 patients suffering from cerebro-vascular occlusive disease and treated by an extra-intracranial anastomosis (EIAB) were examined by 5 different psychological tests (Test d 2, Benton Test, Revision Test, Subtest "ZN" of the Hawie, K-L-T) before and after the operation. The results showed a significant improvement of intellectual functioning in most cases. In a addition, disturbances of drive and activity and symptoms of depression were all diminished.

Attention↗
PubMed1985

Immediate postangiographic intraarterial treatment of cerebral vasospasm after subarachnoid hemorrhage with nimodipine. Report on 3 cases.

Three cases of symptomatic vasospasm after spontaneous subarachnoid hemorrhage are reported. Vasospasm occurred preoperatively in two instances and postoperatively in another. All three cases received an intraarterial perfusion with 0.2 mg nimodipine (BAY e 9736) per hour for 90 minutes. Resolution of the spasms was demonstrated by angiography. As there were no side effects attributable to this form of treatment, new possibilities for neuroradiological intervention may arise in selected cases.

Adult↗
PubMed1985

[Revascularization of extensively stenosed or nearly occluded carotid arteries].

Various therapeutical procedures in patients with extensive and/or distal stenoses of the internal carotid artery (ICA) are discussed. Possible complications are pointed out, such as cerebral embolism during percutaneous intraluminal angioplasty or symptomatic occlusion of the stenotic segment after extracranial-intracranial arterial bypass operation involving haemodynamic changes. In suitable cases, a combined method of endarterectomy and angioplasty is recommended, and the results of 8 cases treated by this method are reported with a distinct post-operative increase of the ICA blood flow. Follow-up remained without recurrent ischaemic attacks.

Aged↗
PubMed1984

Cerebral protection during carotid endarterectomy--EEG monitoring as a guide to the use of intraluminal shunts.

The authors have reviewed the literature concerning measures for cerebral protection during carotid endarterectomy, with particular reference to the controversy regarding the use of an intraluminar shunt. The authors use preoperative EEG analysis during the carotid compression test as well as intraoperative EEG monitoring, and insert a shunt only when signs of cerebral ischaemia appear. This approach was used in 100 patients during a 4 year period and an internal shunt was required in only 10% of these patients. The mortality was 1% and morbidity 1% in this series. The authors believe that EEG monitoring is a reliable technique in detecting signs of cerebral ischaemia before irreversible changes occur and that an intraoperative shunt should be used only when necessary, and not routinely, as it may contribute to operative and postoperative complications.

Adult↗
PubMed1984

Multiple spinal hemangioblastomas in a case of Lindau's disease.

A 32-year-old man with Lindau's syndrome is presented. After an initial operation for cerebellar hemangioblastoma and laser coagulation of retinal tumors, other retinal tumors, a second cerebellar tumor, and four spinal hemangioblastomas occurred 10 years later; cystic lesions of both kidneys and of the pancreas could also be shown. There is no family history. Consequences for further diagnostic procedures in patients with hemangioblastomas are discussed.

Adult↗
PubMed1984

Long term EEG analytical and neurological follow-up study in completed stroke patients after extra-intracranial vascular anastomosis.

In 33 chronic stroke patients, who had internal carotid or middle cerebral artery occlusion that resulted in neurological deficit persisting for an average of more than 10 weeks, it was possible to perform a postoperative follow-up study for a period of six to eight years after extra-intracranial vascular anastomosis. Serial neurological examinations with grading of motor deficit and EEG analyses were performed to assess the clinical course of the cerebral lesion. These long term examinations showed a postoperative continuing improvement of electrical brain activity in nearly two thirds of the patients, nine patients showed no significant changes and three worsened. The EEG analytical findings correlated well to the neurological findings. An increase of electrical brain activity was bilateral with accentuation over the affected hemisphere, a phenomenon known from follow-up nrCBF measurements after anastomosis. During the follow-up one patient died five years, one six years following stroke under signs of cardiovascular disease, and one after six years suffering from a recurrent stroke opposite to the side of anastomosis. In conclusion the findings indicate that EEG analysis is of value for assessment of long term follow-up of cerebral ischaemic lesions, chronic ischaemic alterations of the brain can be improved by anastomosis, and especially in comparison to a non-operated group of stroke patients, the course of the operated one seemed to be more advantageous, as the five-year survival rate of the Framingham study for stroke victims is 69%.

Cerebral Revascularization↗
PubMed1983

[Lasers in neurosurgery].

In recent years neurosurgeons have shown an increasing interest in lasers. An understanding of the basic laser mechanism and tissue effects is important. CO2 laser is an excellent no-touch tool for excising and evaporating brain tumors. It has several other uses in neurosurgery both with free hand technique and with microscope attachment and micromanipulator. Nd: YAG and Argon lasers are more effective for coagulation of blood vessels and dealing with vascular neoplasms. Advantages and disadvantages of this technique are discussed and compared with other methods like bipolar coagulation and CUSA. Indications for the use of the different laser types in neurosurgery are summarized and a prospect of laser in neurosurgery is given.

Brain Diseases↗
PubMed1983

Paragangliomas of the spinal canal.

Paragangliomas are tumors arising in the paraganglia and rarely occur in the spinal canal. In the literature, 11 such cases have been reported. We present 7 additional cases, 3 of which were epidural in location in contrast to previously described intradural cases. The problems of histological diagnosis of these tumors are discussed. The value of determination of biogenic amines in the tumor tissue or the urine has been pointed out.

Adult↗