Biomedical subjects

A Berlis

Publications and source records attributed to A Berlis.

32 records · Page 2Linked to original sources

PubMed2001

Neurosurgical interventions in children with Maroteaux-Lamy syndrome. Case report and review of the literature.

This paper reports the case of a 14-year-old child with Maroteaux-Lamy syndrome (mucopolysaccharidosis type 6) who was treated consecutively for compressive damage of the optic nerves, hydrocephalus communicans and progressive spastic tetraparesis within 2 years. The clinical course of the patient is presented and the pathophysiologic mechanisms of disease progression in patients with Maroteaux-Lamy syndrome are discussed and reviewed.

Adolescent↗

PubMed2000

Detectability and detection rate of acute cerebral hemisphere infarcts on CT and diffusion-weighted MRI.

Our purpose was to compare the detectability and detection rate of acute ischaemic cerebral hemisphere infarcts on CT and diffusion-weighted MRI (DWI). We investigated 32 consecutive patients with acute hemisphere stroke with unenhanced CT and DWI within 6 h of stroke onset. The interval between CT and DWI ranged from 15 to 180 min (mean 60 min). Infarct detectability on CT and DWI was determined by comparing the initial CT, DWI and later reference images in a consensus reading of five independent examiners. The "true" detection rate was assessed by analysing all single readings. Two patients had intracerebral haematomas on DWI and CT and were excluded. There were 27 patients with ischaemic infarcts; all were visible on DWI and proven by follow-up. DWI was negative in three patients without a final diagnosis of infarct (100% sensitivity, 100% specificity, chi2 = 30, P < 0.0001). Ischaemic infarcts were visible on 15 and not seen on 12 CT studies (55 % sensitivity, 100% specificity, chi2 = 1.48, P = 0.224). With regard to the single readings (30 examinations x 5 examiners = 150 readings), 63 CT readings were true positive and 72 false negative (sensitivity 47 %, specificity 86%, chi2 = 2.88, P = 0.089). Of the DWI readings 128 were true positive and 7 false negative (sensitivity 95%, specificity 87 %, chi2 = 70.67, P < 0.0001). Interobserver agreement was substantial for CT (chi = 0.72, 95 % confidence interval, 0.6-0.84) and DWI (chi = 0.82, 95 % confidence interval, 0.46-1). Taken together, detectability and detection rate of acute (< 6 h) hemisphere infarcts are significantly higher with DWI than with CT.

Brain↗

PubMed1999

The role of tumor resection in the treatment of glioblastoma multiforme in adults.

BACKGROUND: The therapeutic impact of tumor resection is poorly defined. Therefore the current study was conducted. METHODS: A retrospective, 2-institutional study was conducted (1991-1994) to compare the treatment results of stereotactic biopsy plus radiation therapy (99 patients; tumor dose: 60 gray [Gy]) with those of surgical resection plus radiation therapy (126 patients; tumor dose: 60 Gy). Only adult patients with supratentorial, lobar located, de novo glioblastoma were included. Survival time was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from the multivariate Cox proportional hazards model. RESULTS: Patients were categorized in the Radiation Therapy Oncology Group (RTOG) Classes IV (46 patients), V (157 patients), and VI (22 patients). The resection group and the biopsy group did not differ in terms of age, pretreatment Karnofsky performance status KPS), gender, duration of symptoms, presenting symptoms, tumor location, tumor size, and the frequency of midline shift. Patients in the biopsy group more often were found to have left-sided tumors (P < 0.001). Transient perioperative morbidity and mortality rates were 1% and 1%, respectively, in the biopsy group and 5% and 1.6%, respectively, in the resection group (P > 0.05). The median survival time was 37 weeks for the resection group and 33 weeks for the biopsy group. The difference was not statistically significant (P = 0.09). The most favorable pretreatment prognostic factor was patient age < 60 years (P < 0.01). Tumor resection was highly effective in patients with midline shift (P < 0.01). In patients without midline shift radiation therapy alone was found to be as effective as tumor resection plus radiation therapy (P = 0.5). Patients with midline shift were more likely to have a worse KPS during the course of primary radiation therapy (P < 0.05). CONCLUSIONS: For RTOG Classes IV-VI patients with moderate mass effect of the tumor, radiation therapy alone is a rational treatment strategy. Tumor resection should be performed in patients with pretreatment midline shift whenever possible.

Adult↗

PubMed1999

[Anticoagulation control during neuroradiological interventions with ACT (activated clotting time)].

PURPOSE: To evaluate the effect of anticoagulation control by bedside ACT during interventional neuroradiological procedures with intraarterial heparin application. MATERIALS AND METHODS: The study included 168 patients with intraarterial anticoagulation. Depending on the expected duration of the intervention and the body weight, a heparin dose of 5000 i.u. (70 patients) or 7500 i.u. (98 patients) was given through the catheter. The clotting time was measured with the Hemochrom 401 (Fa. Fresenius). RESULTS: The effect of anticoagulation with heparin was measurable a few minutes after administration. Within the first 20 minutes the ACT increased about two times above the normal ACT from 156.1 +/- 26.1 (5000 i.u. heparin) to 296 +/- 58.0 and from 146.5 +/- 26.3 (7500 i.u. heparin) to 317.2 +/- 72.0. Additional administration of 2500 i.u. heparin was necessary in 16 patients. An ACT monitored neutralisation with protamine hydrochloride took place in 15 patients with high ACT values at the end of the intervention. Three thromboembolic events and one bleeding complication occurred during the interventions. CONCLUSIONS: (1) The ACT is a useful and readily available parameter to monitor the anticoagulation status of patients in the interventional suits. (2) ACT detects heparin nonresponders. (3) Exact monitoring of heparin administration and neutralisation with protamine hydrochloride is helpful in preventing thromboembolic events and bleeding complications.

Anticoagulants↗

PubMed1999

Polyethylene terephthalate and polyurethane coatings for endovascular stents: preliminary results in canine experimental arteriovenous fistulas.

PURPOSE: To evaluate polyethylene terephthalate and polyurethane as coatings of vascular endoprostheses in the treatment of experimental arteriovenous fistulas (AVFs). MATERIALS AND METHODS: Nineteen bilateral carotid artery-to-external jugular vein AVFs were created in 10 adult dogs. Fourteen polyethylene terephthalate-coated and five polyurethane-coated self-expandable nitinol stents were placed with a transfemoral approach. Angiography was performed immediately after placement, after 1 and 3 weeks, and at months 3, 6, 9, and 12. All grafts were examined histopathologically. RESULTS: The AVF was successfully occluded with all but one of the polyethylene terephthalate-coated stents. Graft patency was seen with 12 polyethylene terephthalate-coated stents, while acute vessel occlusion was evident with two polyethylene terephthalate-coated stents following percutaneous transluminal angioplasty immediately after implantation. In the group with polyurethane-coated stents, three graft dislocations and two delayed vessel occlusions were observed. In both groups, histologic examination disclosed a mild foreign body reaction with a few macro-phages. No inflammatory reactions were seen. An unorganized fibrin layer was found adjacent to the polyurethane coating. CONCLUSION: Polyethylene terephthalate-coated nitinol stents showed good biocompatibility and a high rate of occlusion of experimental AVFs. The mechanical properties of the polyethylene terephthalate coating were similar to those of the nitinol stents, which facilitated handling. Polyurethane-coated stents showed frequent dislocation.

Alloys↗

PubMed1999

A new technique for oral endotracheal airway access in rabbits under fluoroscopic control: An easy way for drug administration in chronic experiments.

Endotracheal drug administration plays an important role in rabbit models of pulmonary injury and lung disease. However, anatomical features of the oral fissure and pharynx of rabbits make orotracheal intubation a difficult task with a high failure rate. We developed a new technique for airway access in rabbits under fluoroscopic control using a balloon catheter. The procedure consists of four major steps: (1) a shortened 5-french vertebralis catheter is placed into the mesopharynx just above the epiglottic valve, (2) through the catheter lumen a guidewire is carefully moved across the epiglottis and inserted into the trachea, (3) the vertebralis catheter is replaced by a balloon catheter that subsequently is introduced into the tracheal tree over the guidewire, and (4) with the balloon catheter in the right position the guidewire is removed and the balloon is inflated so that finally the drug can be delivered. This procedure was performed in 55 New Zealand White rabbits under general anesthesia with ketamine/xylazine. In all 55 cases the procedure was performed successfully without any major complications and within a reasonably short time period. Removal of the catheter and awakening of the animals were uneventful. The described technique is a simple and safe method for airway access in rabbits and can be useful in chronic experiments for endotracheal drug administration.

Animals↗

PubMed1997

Significant reduction of seizure incidence and increase of benzodiazepine receptor density after interstitial radiosurgery in low-grade gliomas.

Epilepsy is the leading symptom in low grade gliomas. In order to evaluate the effect of interstitial radiosurgery on seizure incidence the authors retrospectively analysed the outcome of 80 patients with temporal grade-II astrocytomas and a history of epilepsy. Patients were treated by 125-iodine temporary implants using 60 Gy as reference dose. The dose rate was 9.6 +/- 1.6 cGy/h. Median follow-up was 4.1 years. In 20 patients benzodiazepine receptor imaging was performed using single photon emission computed tomography and iomazenil. Treatment with carbamazepine alone led to a significant reduction in seizure incidence with 28% of patients being seizure-free (p < 0.05). Interstitial radiosurgery led to a further reduction of seizures rendering 40% of patients seizure-free after 3 months. After 6 months only 21% of patients still had seizures that were refractory to medical treatment (p < 0.01). SPECT imaging revealed that all tumours had a significant reduction of benzodiazepine receptors which also applied to the surrounding brain. After interstitial radiosurgery of tumours, receptor density increased in brain adjacent to the tumour (0.68 to 0.94 ratio ipsi to contralateral brain, p < 0.01) coincident with significant tumour shrinkage. Thus, in epileptogenic temporal low grade gliomas, interstitial radiosurgery not only reduced the tumour burden but also effectively treated the concomitant epilepsy, resulting in 79% of patients being seizure-free after combined treatment by radiosurgery and anticonvulsive medication. These results compare favourably to the outcome after resection in lesional epilepsy raising the issue of radiosurgery as a less invasive alternative to open epilepsy surgery.

Adult↗

PubMed1997

Effect of LINAC radiosurgery on regional cerebral blood flow, glucose metabolism and sodium-potassium AtPase in skull base meningiomas and metastasis.

Stereotactic radiosurgery is an elegant alternative to microsurgery in both skull base meningiomas and solitary brain metastasis. Though efficacy for both entities has been established prognostic variables pertaining to individual tumour biology have not yet been identified. Therefore the authors measured regional glucose utilisation, thallium-uptake and blood flow in 20 patients (10 meningiomas, 10 metastasis) before and after LINAC radiosurgery. Measurements were performed using SPECT and stable xenon-CT. The mean tumour dose given was 16.3 and 19.5 Gy in meningiomas and metastasis respectively. Metastatic tumours were hypermetabolic in comparison to contralateral normal brain and responders to radiosurgery showed a lower tumour/brain ratio than non-responders (1.43 vs 0.91 respectively, p < 0.01). Meningiomas did not exhibit hypermetabolism and therapeutic outcome was not related to glucose utilisation. Thallium-uptake, however, was closely related to therapeutic response in meningiomas (1.37 vs 2.2 in responders vs non-responders, p < 0.01). This relationship could not be established in metastatic lesions. Blood flow was widely distributed in both meningiomas and metastasis (26-72.8 and 30.2-70.8 ml/100 g/min). rCBF did not correlate with therapeutic outcome. Using FDG-SPECT and thallium-201-SPECT the authors were able to distinguish between tumours likely to respond to stereotactic radiosurgery and those not prone to respond. Furthermore the methodology can be used to monitor therapeutic response in treated tumours before morphologic changes occur.

Adult↗

PubMed1997

MRI of active otosclerosis.

Our aim was to determine whether MRI reliably shows pathology in patients with active otosclerosis (otospongiosis). We studied five patients with clinical and audiometric signs of this disorder and positive findings on high-resolution CT and tympanocochlear scintigraphy. Contrast enhancement of otospongiotic lesions was found in all affected ears, and could be topographically related to demineralised otospongiotic foci on CT. In lesions in the lateral wall of the labyrinth MRI sometimes showed the pathology better than CT, where partial-volume effects could be troublesome.

Adolescent↗

PubMed1997

Poly-lactic-acid coating for endovascular stents. Preliminary results in canine experimental arteriovenous fistulae.

RATIONALE AND OBJECTIVES: The authors evaluate polylactic-acid (PLA) as a coating of vascular endoprostheses in the treatment of experimental arteriovenous fistulae (AVF) in a canine model. METHODS: Bilateral carotid external jugular AVF were created in five adult dogs. Seven PLA-coated nitinol stents were placed using a transfemoral approach to cover five AVF. Contralateral controls remained untreated. Angiography was performed immediately after stent placement and at weeks 1 and 3, as well as at months 3, 6, and 9. All grafts were removed and underwent histologic examination. RESULTS: In two cases, the occlusion of the AVF was successful, but misplacement of stents occurred in three cases, which showed occlusion of the parent vessel between week 1 and month 3. One thrombembolic stent occlusion was evident during angiographic control. One vessel occlusion was disclosed distal to the stented arterial segment. Histologic examination revealed a mild inflammatory reaction with the presence of macrophages. However, there was no foreign-body reaction of fragmentation of the vessel wall. CONCLUSIONS: Histologic examination revealed good biocompatibility of PLA, which is a well-known biodegradable material. Elastic mismatch of the nonelastic coating and the self-expandable nitinol stent led to misplacement, whereas vessel occlusion was probably due to PLA filaments fraying into the vessel lumen. Using a different textile structure, PLA might be a material suitable for coated stents.

Alloys↗

PubMed1995

Localization of active otosclerotic foci by tympano-cochlear scintigraphy (TCS) using correlative imaging.

High-resolution, tympano-cochlear scintigraphy (TCS) is a useful tool for visualizing changes in labyrinthine bone metabolism in active otosclerosis in vivo. But until now, the activity patterns have mostly been rather imprecisely ascribed to the labyrinthine structures; more exactly by means of high-resolution CT (HR-CT). Experimental studies on TCS using a human temporal bone model revealed that correlative imaging of X-ray photographs and the scintigrams or superimposition with masks of the temporal bone drawn from the X-rays can facilitate the localization of small foci of about 0.5-1 mm. Clinical applications of the visualization technique, combining functional with structural images, confirmed the benefit of this method, improving the accuracy in detection and localization of focal activity enrichment of the petrous bone in cases of active otosclerosis by means of TCS.

Diphosphonates↗

PubMed1995

[High resolution computerized tomography of the petrous bones in a bone algorithm and 2D reconstruction for evaluation of the facial nerve canal].

Radiographic imaging of the intratemporal portion of the fallopian canal is important in cases of traumatic facial nerve palsy to visualize the site of involvement. Even if high-resolution computed tomography is used, several images in various planes are necessary to obtain satisfactory diagnostic information. By using a classic axial scan and a wide window (bone algorithm), a 2D reconstruction can be performed "off-line" to visualize the mastoid portion of the fallopian canal. A reconstruction plane 45 degrees to the median-sagittal plane and through the lateral genu of the facial nerve provides the best imaging of the mastoid portion down to the stylomastoid foramen. In cases of temporal bone fractures with facial paralysis, an excellent demonstration of fracture line without further radiation exposure can be obtained in cases considered for surgical decompression.

Adult↗

PubMed1992

Direct and CT measurements of canals and foramina of the skull base.

This investigation is based on measurements of 60 macerated adult European skulls from the Alexander-Ecker Collection at the Anatomy Department of the University of Freiburg. Computer tomographical (CT) and anatomical measurements were compared to assess the accuracy of the CT representation of osseous structures. Nine structures were examined: the optic canal; the superior orbital fissure; the foramen rotundum; the foramen ovale; the foramen spinosum; the foramen Vesalii (venosum); the carotid canal; the internal auditory canal, and the hypoglossal canal. The results show a good and even excellent correlation if the cranial opening is approximately at a right angle to the scanline. For this reason, the results of the coronal examination of the internal auditory canal are less satisfactory, and the coronal and axial measurements of the hypoglossal canal show only a moderately good correlation.

Cephalometry↗

PubMed1992

[Measurements and variations in the region of the optic canal. CT and anatomy].

This investigation of the optic canal is based on measurements of 60 macerated adult European skulls from the Alexander-Ecker Collection at the Anatomy Department of the University of Freiburg. An indian skull is also described, in which the cranial end of the left optic canal is closed by a bony plate. Computer tomographical and anatomical measurements were compared in order to assess the correlation of the two methods of investigation and the accuracy of the CT representation of osseous structures. The coronal projection of the optic canal proved to be optimal for CT examination--the sections meet the optic canal at an angle of 85.5 degrees. The measurements of transverse diameters correlate poorly, whereas vertical diameters and distances correlate well. The extent to which anatomical variations can be assessed by CT was also investigated. All anatomical variants could be observed in coronal sections, except the bony lamina in the Indian skull, which could not be seen until a contrast medium was used. The so-called "keyhole anomaly" appeared in 3.3% in our material, the "figure-of-eight" variant in 2.5%, and a carotid clinoid canal in 13.3%.

Adult↗