Biomedical subjects
Publications and source records attributed to A Raabe.
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BACKGROUND: The quality of the contributions to "Strahlentherapie und Onkologie" is assessed, aiming for improvement of the journal and consequently its impact factor. MATERIAL AND METHODS: All 164 articles published during 1999 and 2000 in the categories "review article", "original article", and "short communication" were analyzed concerning number and age of references. RESULT: In 1999 and 2000 there was a median number of 26 citations per article (range: 0-264). The median age of the cited articles was 4 years. CONCLUSION: The work of other authors should properly be referred to. Citation of the same journal might influence the impact factor of the journal.
BACKGROUND: Gaps are a common feature of clinical radiotherapy. Only little information is available about the influence of the position of a gap on tumor response. MATERIAL AND METHODS: In a rodent tumor model (rhabdomyosarcoma R1H of the rat) three split-course schedules were carried out by inserting a 2-week gap either after the 1st, the 3rd, or the 5th week into a standard schedule of 30 fractions in 6 weeks. For comparison a standard and an accelerated treatment were carried out. RESULT AND CONCLUSION: The position of the gap was found to have a significant influence on the tumor response (p = 0.018).
BACKGROUND AND PURPOSE: In clinical practice a concomitant boost is usually given as a second daily dose to a reduced field. The question arises which part of treatment should be accelerated to achieve optimal tumor control. An experiment was performed on tumor bearing rats to determine the optimal timing of treatment acceleration for this experimental tumor system. MATERIAL AND METHODS: Rhabdomyosarcoma R1H of the rat were treated applying 30 fractions in an overall treatment time of 40-42 days, up to total doses ranging from 67.5 to 97.5 Gy were administered. For control a standard treatment was given as continuous treatment applying one fraction per day. A boost of five additional fractions was given as a second fraction during 5 days. Three experimental arms received a boost either in the 1st, 4th, or in the last week of treatment. Treatment outcome was assessed using tumor control as endpoint. RESULTS: All experimental arms proved more effective than the standard treatment. Treatment was most effective when the boost was administered in the 1st week of treatment. A TCD37% of 87.1 Gy (95% CI: 82.8 ... 92.7 Gy), 96.5 Gy (89.9 ... 107.1), and 107.3 Gy (97.2 ... 131.0) was determined, when the boost was given in the 1st, 4th, or last week of treatment, respectively. The observed difference between the experimental arms was statistically significant (p = 0.004). CONCLUSIONS: Initially accelerated treatment schedules were found to be more effective for tumor control in an experimental tumor system.
OBJECTIVES: Preservation of brain function while maximizing resection is the main aim of brain tumour surgery. The purpose of this study was to evaluate the efficacy of intra-operative magnetic resonance imaging to preserve brain function in patients with tumours in or near eloquent brain areas. METHODS AND MATERIAL: Between August 1997 and January 1999 fifty-eight craniotomies for intracranial tumours or vascular malformations have been performed at the University of Leipzig using a 0.5 T superconducting MR system "SIGNA SP" (General Electric Medical Systems, USA). In 32 of these patients (15 male/17 female) with intracranial tumours, located in or near eloquent brain areas (sensorimotor cortex/speech center), 34 craniotomies were performed using the image guidance of the interventional MRI. RESULTS: Using intra-operative MRI criteria, complete tumour removal could be achieved in 28 (82%) of 34 procedures. In 3 patients only subtotal tumour removal was possible, because the residual tumour was not visible on the intra-operative MR images, but could be identified on early diagnostic follow-up MR-scans. In 3 patients, incomplete tumour resection was performed in order to avoid neurological impairment. In these patients intra-operative MR-images revealed residual tissue abnormalities involving or encroaching on deep brain structures or motor/language cortex. Pre-operative neurological status was unchanged in 24 patients (70%), worsened in 4 patients (12%) and improved in 6 patients (18%). CONCLUSIONS: Intra-operative MRI is helpful for navigation as well as to demonstrate the tumour margins to achieve a complete and safe resection of intracranial lesions located in or near eloquent brain areas. It enables an image based functional monitoring of the brain which is critical for motor, sensory or language function. Complications related to the surgical procedure are reduced and the risk of neurological deterioration due to tumour removal and postoperative complications is minimized.
OBJECTS: To analyze the management-related morbidity and mortality in unselected aneurysms of the basilar trunk and vertebrobasilar junction. The secondary objective was to investigate the factors associated with favourable or unfavourable surgical outcome in order to define subgroups for surgical and endovascular treatment. METHODS: 24 consecutive patients with aneurysms of the basilar trunk and vertebrobasilar junction were included in this study. They comprised 2.7% of all aneurysms treated during the study period between 1990 and 1997. 22 patients presented with acute subarachnoid hemorrhage (SAH) and 2 patients with symptoms of brainstem compresssion. All patients were managed using a standard protocol including surgery at the earliest possible moment, aggressive tripe-H therapy in patients with symptomatic vasospasm and mandatory follow-up angiography. 23 patients underwent surgical clipping and one patient endovascular coiling of the aneurysm. 12 patients had an excellent outcome. 6 patients had a good outcome, resulting in a total of satisfactory outcomes in 18 patients (75%). 4 patients (17%) had moderate to severe deficits. Two patients died (8%). Both patients had fusiform basilar trunk aneurysms. Good or excellent outcome was observed in 7 of 8 patients with aneurysms of the vertebrobasilar junction, 13 of 14 patients with moderate or minor SAH or without SAH (Fisher grade 0 to 2) and all patients with small sized aneurysm (n = 6). Factors mostly associated with poor outcome or death after surgical treatment were aneurysm location at the basilar trunk, large aneurysm size or fusiforme aneurysm type and severe SAH. CONCLUSIONS: Location, aneurysm size and the severity of SAH may help to predict the subgroup which highly benefits from surgical clipping of these rare vascular lesions.
BACKGROUND: To analyse the rate of postoperative haemorrhage during a 4-year period of early postoperative administration (< 24 hours) of fractionated heparin plus compression stockings in a large cohort of patients undergoing intracranial surgery. METHOD: A total of 1564 patients who underwent intracranial surgery at our institution were included in our study. 1197 of the 1564 patients (77%) had major intracranial surgery (group 1). Group 2 was made up of 367 patients in whom ventriculoperitoneal shunting or external ventriculostomy was performed (minor intracranial procedures). All patients were investigated retrospectively for the occurrence of major postoperative haemorrhage confirmed by CT scanning and requiring surgical evacuation. The protocol for prophylaxis of thrombo-embolic events included early (< 24 hours) postoperative fractionated low-dose heparin (3 x 5000 IE subcutaneously) until discharge plus intra- and postoperative compression stockings. FINDINGS: Major postoperative haemorrhages were observed in 31 of the 1564 patients (2.0%). In three patients, the haemorrhage occurred on the day of surgery before the administration of heparin. The haemorrhage rate of patients receiving heparin was 1.8% (28/1564). All haemorrhages occurred in patients undergoing major intracranial procedures (group 1; 31/1197; 2.6%). There was no haemorrhage in minor intracranial procedures (group 2; 0/367; 0%). INTERPRETATION: Although retrospective, this is to date the largest study supporting the concept of postoperative pharmacological thrombo-embolic propylaxis in patients undergoing intracranial surgery. The question as to whether pharmacological prophylaxis is beneficial for a given patient can only be answered by weighing the risk reduction of thrombo-embolic events against the risk increase of postoperative haemorrhage associated with different surgical procedures and heparin protocols.
The authors report the case of a 10-year-old girl with intervertebral disc calcifications from the levels C6/C7 to Th1/Th2, presenting with a herniated calcified intervertebral disc at the C7/Th1 level, causing spinal cord compression with subsequent progressive paresis and sensory loss of her left leg. After anterior cervical discectomy and fusion the neurological deficits completely resolved within 2 weeks. It can be concluded that calcification of an intervertebral disc is a rare syndrome in childhood, causing progressive neurological deficit only in a few reported cases. Although the treatment of choice is conservative, surgery is required in patients who develop progressive neurological deficit.
PURPOSE: The aim was to investigate the influence of pulmonary metastases of the rhabdomyosarcoma R1H on the radiation response of the lung of the WAG/Rij rat. MATERIAL AND METHODS: Three groups of animals were investigated: metastases-free animals treated with fractionated irradiation of the lungs; metastases-bearing animals receiving no irradiation; and metastases-bearing animals treated with fractionated irradiation initiated 14, 21 or 28 days after induction of pulmonary metastases of the R1H-tumour by i.v. injection of viable tumour cells. Metastases were thus treated at various well-defined sizes. Total doses of 20-60Gy were applied in fractions of 2 Gy within 11 days. Complication rate and survival time were used as endpoints. RESULTS: About 2 months after onset of irradiation treatment, animals had to be sacrificed because of severe respiratory distress either caused by irradiation-induced lung damage (median 57 days, range 36-77 days), or because of development of lung metastases (65, 20-160 days). A decrease of the ED(50) (dose required to induce lethal lung damage in 50% of irradiated animals) was determined for metastases-bearing animals. This effect increased with metastatic volume. CONCLUSIONS: The results suggest that the presence of tumours in the lung decreased the lung tolerance to radiation. This effect can hardly be explained by a reduction in functional lung volume by metastatic volume.
OBJECTIVE: Endothelin (ET)-1 may be involved in the regulation of cerebrovascular resistance under pathological conditions, most notably during the development of vasospasm after subarachnoid hemorrhage. Blocking ET-converting enzyme activity may be a promising approach to the prevention of cerebral vasospasm after subarachnoid hemorrhage. METHODS: In this study, the effects of several putative ET-converting enzyme inhibitors were investigated after intracisternal application in rabbits, to inhibit basilar artery contractions induced by big ET-1 (2 x 10(-6) mol/L). RESULTS: In the group pretreated with [D-Val22]big ET-1[16-38] (2 x 10(-5) mol/L) (n = 8), the angiographically measured diameter of the basilar artery changed from 0.63 +/- 0.12 mm to 0.66 +/- 0.12 mm. In the control group (n = 8), the diameter of the basilar artery decreased from 0.71 +/- 0.13 mm to 0.57 +/- 0.15 mm. These results corresponded to an increase in vessel diameter of 5 +/- 10% in the treatment group and a decrease in vessel diameter of 20 +/- 16% in the control group (P = 0.014). In the group pretreated with captopril (2 x 10(-4) mol/L) (n = 8), the angiographically measured diameter of the basilar artery changed from 0.64 +/- 0.11 mm to 0.71 +/- 0.10 mm. These results corresponded to an increase in vessel diameter of 14 +/- 19% in the treatment group, compared with a decrease in vessel diameter of 20 +/- 16% in the control group (P = 0.014). CONCLUSION: These results demonstrate that [D-Val22]big ET-1[16-38] and captopril act as highly potent ET-converting enzyme inhibitors, affecting big ET-1-induced contraction of the rabbit basilar artery.
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The experimental design of studies using small laboratory animals may require repeated venous access for the application of drugs or diagnostics. An appropriate device should provide quick intravenous access without causing severe handling stress to the animals or the necessity of anaesthesia. In addition, the system should be suitable for repeated injections over several weeks. A silicone catheter is connected to an intravenous indwelling cannula with fixation wings. A closure stopper with injection port completes this system. The device is fixed subcutaneously on the back of the animal and the catheter is inserted into the jugular vein. The device is easily and quickly assembled and is more economic than commercial systems. It is easily implanted and allows repeated intravenous injections for several weeks without anaesthesia or restraint of the animals. The method allows repeated intravenous drug delivery over a couple of weeks in small animals.
BACKGROUND: The statistical quality of the contributions to "Strahlentherapie und Onkologie" is assessed, aiming for improvement of the journal and consequently its impact factor. MATERIAL AND METHODS: All 181 articles published during 1998 and 1999 in the categories "review", "original contribution", and "short communication" were analyzed concerning the appropriate consideration of Type II error. RESULT: Ninety-nine publications were excluded from analysis for different specified reasons. In none of the remaining 82 clinical publications Type II error was considered. CONCLUSION: Authors, peer reviewers, and editors could contribute to improve the quality of the journal by setting value on adequate consideration of Type II error.
The objective of our study was to investigate S-100B protein as a serum marker of brain cell damage after severe head injury. Eighty-three patients with severe head injury (Glasgow Coma Scale < or =8) were included in this prospective study. Venous blood samples for S-100B protein were taken after admission and every 24 h for a maximum of 10 consecutive days. Outcome was assessed at 6 months using the Glasgow Outcome Scale. In this study, we analysed the preliminary results from the outcomes of 25 patients at 6 months. Levels of S-100B were significantly higher in patients with unfavourable outcome compared to those with favourable outcome. In patients with favourable outcome, slightly increased initial levels of S-100B returned to normal within 3 to 4 days. In patients with unfavourable outcome, initial levels were markedly increased, with a tendency to decrease from day 1 to day 6. After day 6, there was a secondary increase in serum S-100B, indicating secondary brain cell damage. Our preliminary results suggest that serum S-100B protein might be a promising biochemical marker which may provide additional information on the extent of primary injury to the brain and the prediction of outcome after severe head injury.
OBJECTIVES: A number of different image-guided surgical techniques have been developed during the past decade. None of these methods can provide the surgeon with information about the dynamic changes that occur intra-operatively. The development of open configurated MRI-scanners leads to new perspectives in the intra-operative management and resection control of intracranial tumours. MATERIAL AND METHOD: Using a vertical open 0.5 T MRI-scanner for intra-operative MR image guided neurosurgery, forty-four patients (20 female/24 male) with different intracranial tumours have been operated on since August 1997. The patients ranged in age from 20 to 70 years (mean +/- standard deviation = 47.2 +/- 15.9 ys). RESULTS: In 36 (82%) of 44 patients the tumours were completely removed with the aid of MR image-guidance. In 8 cases (18%) complete removal was not achieved. Postoperatively 6 (14%) of 44 patients developed neurological deficits which were transient in 5 cases (paresis, dysphasia). In these patients the tumours were located in or near eloquent brain areas (sensorimotor cortex/speech center). CONCLUSION: Intra-operative MRI is helpful for navigation as well as determining of tumour margins to achieve a complete and safe resection of intracranial lesions. Complications related to the surgical procedure are reduced and the risk of neurological deterioration due to tumour removal and postoperative complications is minimized. It can be concluded that the intra-operative application of interventional MRI technology may represent a major step foreward in the field of neurosurgery.
BACKGROUND: Factor XIII is of physiological importance for hemostasis, especially in patients undergoing surgery. It catalyzes the enzymatic cross-linking of fibrin monomers into stable polymers and protects polymers from plasmatic and nonspecific degradation. Postoperative hemorrhage in patients with congenital and acquired Factor XIII deficiencies has been described in various surgical fields. However, there are no data about the incidence and clinical relevance of decreased Factor XIII after neurosurgical procedures. The objective of our study was to investigate the association between Factor XIII deficiency and postoperative hemorrhage after intracranial surgery. METHODS: A total of 1264 patients who underwent intracranial operations were reviewed retrospectively. Standard coagulation parameters were monitored during the perioperative course in all patients. Factor XIII testing was performed postoperatively in 34 patients in whom coagulopathies were suspected despite normal platelets, fibrinogen, prothrombin, and partial thromboplastin time. Data were analyzed to evaluate the association of Factor XIII deficiency and major postoperative hemorrhage. RESULTS: In this series of 1264 patients, a total of 20 patients (1. 6%) suffered from a major postoperative hemorrhage. Of the 34 patients with suspected coagulopathies and postoperative Factor XIII testing, 11 had a major postoperative hemorrhage. Normal levels of Factor XIII, defined as more than 60%, were found in 26 of the 34 patients. Factor XIII deficiency, defined as less than 60%, was found in eight patients. All patients with Factor XIII deficiency (n = 8) had a major postoperative hemorrhage. Of the remaining 26 patients with normal Factor XIII levels only three had a postoperative hemorrhage (p < 0.00001, Fisher's exact test). CONCLUSIONS: Decreased Factor XIII activity may be associated with an increased risk of postoperative hemorrhage after intracranial surgery.
BACKGROUND AND PURPOSE: Macroscopic subcutaneously growing R1H-tumours have been shown to respond almost independently of the dose per fraction when treated under ambient conditions. In addition decelerated repopulation during fractionated irradiation has been shown for this experimental tumour. The aim of the present study was to investigate whether this is also the case for pulmonary micrometastases which are assumed to be fully oxygenated or whether differences in the oxygenation status of the tumour possibly alters its response to fractionation. The influence of the dose per fraction and overall treatment time on the response of micrometastases to fractionated irradiation was studied. MATERIALS AND METHODS: Pulmonary metastases were induced by i.v. injection of viable tumour cells. Treatment was started 14 days later, when metastases reached an average size of four cells. Total doses of 16 to 28 Gy were administered within an overall treatment time of 11 or 25 days, using doses per fraction of 1, 2, or 4 Gy. Tumour response was quantified by metastatic control (MCD(37%)). RESULTS: Fractionation had a significant influence on local control (P=0.009). After application of 1, 2, or 4 Gy and an overall treatment time of 11 days the MCD(37%) was 25.4 (95% C.I.: 21.5-32.0) Gy, 20.7 (17. 0-24.0) Gy, and 18.5 (14.9-21.6) Gy, respectively. When overall treatment time was prolonged to 25 days the MCD(37%) increased to 25. 5 (21.3-33.5) Gy when fractions of 2 Gy where applied, but this difference was not significant (P=0.13). The doubling time of 12.8 days determined for the metastatic clonogenic tumour cells during fractionated irradiation was significantly longer than the 4.1 days observed for untreated metastases (P=0.006). CONCLUSIONS: The results show a strong influence of fractionation on treatment outcome and a decelerated repopulation during fractionated irradiation treatment for well oxygenated pulmonary metastases of the R1H-tumour.