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Biomedical subjects

E Uhl

Publications and source records attributed to E Uhl.

At least 19 recordsLinked to original sources
PubMed2005

Thermography - a valuable tool to test hydrocephalus shunt patency.

INTRODUCTION: Shunt-function in hydrocephalic patients is verified by clinical examination and repeated cranial computed tomography (CCT) in most cases. Because of the disadvantages of multiple radiation especially in children it was our aim to introduce video-thermography as a simple and non-invasive methodology to evaluate shunt function. METHODS: 54 patients treated with shunts for hydrocephalus were tested. A ventriculo-peritoneal shunt had been implanted in 38 patients, a ventriculo-atrial shunt in 16 patients. Recent CCT-scans were available for all patients and served as control. None of the patients presented with clinical signs of shunt-dysfunction. The temperature of the skin covering the drainage catheter distal to the valve was recorded real-time by a calibrated infrared camera. After cooling the skin area downstream of the valve for exactly 1 min with an ice pack, changes of the skin temperature in the area downstream were registered by a thermocamera. The signals were transferred to a video screen and recorded on videotape. By off-line analysis of the obtained pseudo colour images variations of 0.1 degrees C in skin temperature could be measured. RESULTS: Temperature distribution of the area under investigation revealed a significant reduction of the skin temperature according to the location of the downstream catheter segment in 48 patients after cooling. In 6 patients skin temperature remained constant, although clinical evaluation and CCT-scan showed no signs of shunt dysfunction. Shunt patency could be verified in more than 85% of the patients by thermal imaging. CONCLUSION: Infrared-thermography is a valuable and promising tool for replacing CCT-scanning as a screening method to test shunt function in hydrocephalic patients.

Adolescent↗
PubMed2005

Head injury after a fall on stairs: poorer prognosis in inebriated patients?

AIM: The aim of the present study was to determine whether inebriated patients falling on stairs sustain more severe head injuries than sober patients because of a delayed reaction time and a pathological coagulation and clotting system. PATIENTS AND METHODS: The files of 140 head-injured patients who came to admission after falling on stairs were retrospectively reviewed with respect to demographic data, initial Glasgow coma scale (GCS) score, type of hematoma, coagulation parameters and outcome (death versus survival, Glasgow Outcome Scale [GOS] score GOS 3-5 vs. GOS 1 and 2). RESULTS: There were 69 patients who had an alcohol level of > or = 0.8 parts per thousand at the time of the fall (49.0 %). The mortality in the group of inebriated patients was 12.9 %, in the group of sober patients 33.3 % (p = 0.001). The characteristics of the two groups were comparable, except for age (50.4 vs. 69.1 years, p = 0.001). The analysis of mortality in relation to age confirmed the finding of a lower mortality rate in inebriated patients. CONCLUSION: The hypothesis that inebriated patients sustain more severe head injuries with higher mortality rates could not be validated. Routine laboratory tests did not detect coagulation and clotting disorders in inebriated patients. Instead, our study again showed that age is one of the major prognostic factors in head injury.

Aged↗
PubMed2005

Gamma-knife surgery is effective in normalising plasma insulin-like growth factor I in patients with acromegaly.

OBJECTIVE: For patients in whom acromegaly persists despite pituitary surgery or drug treatment, gamma-knife surgery represents an additional treatment option. Considering carefully the different reported biochemical outcomes, the central point is whether gamma-knife radiosurgery has advantages compared to conventional radiotherapy or, furthermore, to newer medical therapies, such as long-acting somatostatin analogues or growth hormone receptor antagonists. DESIGN AND METHODS: We report the outcome of 44 patients with acromegaly, who received gamma-knife surgery with the Leksell gamma knife. The median follow-up time was 1.9 years (0.5-4.3 years) post-radiosurgery. 43 of 44 patients had previously undergone pituitary surgery. RESULTS: Immediately prior to gamma-knife surgery, median xULN of patients' serum IGF-I was 1.9 times above upper limit of normal (range: 0.5-8.9 xULN [multiple of upper limit of normal range]). There was a significant decline of serum IGF-I at patients' final follow-up. We found a normal age-adjusted IGF-I in 21/44 patients (xULN of IGF-I<1). Furthermore, as the number of treated patients increased, we found an improvement in remission rate, which let us assume that there was a learning effect for the gamma-knife performing team over time. In addition, the median adenoma size decreased from 1.5 ml (0.1-6.9 ml) prior to gamma-knife therapy to 0.3 ml (no rest vol. detectable-2.4 ml) at patients' last visit. CONCLUSION: We have shown that pituitary gamma-knife surgery is effective in lowering serum IGF-I levels. At the end of the follow-up period, 48 % of our cohort had normal age-adjusted IGF-I levels.

Acromegaly↗
PubMed2005

Bacterial endotoxin (lipopolysaccharide) stimulates interleukin-6 production and inhibits growth of pituitary tumour cells expressing the toll-like receptor 4.

Members of the Toll receptor (Tlr) family have a crucial role in the innate immune response following bacterial infection. The effects of Gram-negative bacteria-derived endotoxins (lipopolysaccharide, LPS) are predominantly mediated by Tlr4, and we have recently shown that pituitary folliculostellate cells express functional Tlr4. In the present study, we investigated whether Tlr4 is also present in normal and transformed endocrine epithelial pituitary cell types. By reverse transcriptase-polymerase chain reaction, Tlr4 mRNA expression was found in some pituitary epithelial tumour cell lines (AtT20, HP75), whereas others were negative (GH3, alphaT3-1). Tlr4 protein was detected by immunohistochemistry in a few epithelial cells in normal human anterior pituitaries and in 26 out of 67 human pituitary tumours analysed. LPS had no effect on adrenocorticotropic hormone secretion in Tlr4-positive AtT20 cells, but it suppressed the growth of these cells in a dose-dependent manner. As expected, neither hormone secretion, nor growth of Tlr4-negative GH3 cells was affected by LPS. In cell cultures of Tlr4-positive pituitary adenomas, LPS dose-dependently stimulated the production of interleukin (IL)-6, which is known to induce growth and hormone production in pituitary tumours. The LPS-induced IL-6 production was blocked by the specific p38alphaMAP kinase inhibitor, SB203580, and by the synthetic glucocorticoid, dexamethasone. The data suggest that, during Gram-negative bacteria-induced infections or inflammatory processes, LPS could affect pituitary tumour pathophysiology and progression in the subset of Tlr4-expressing pituitary adenomas.

Adenoma↗
PubMed2004

[Pituitary insufficiency following head injury--how common is it, and what is to be done?].

In Germany,traumatic brain injury (TBI) has an annual incidence of approximately 200000. In contrast to earlier assumptions, pituitary insufficiency is a common complication of TBI, with a prevalence of 30-50%. Since the symptoms are often nonspecific and may be masked by the sequelae of head injury, it may go unrecognized and may possibly aggravate the symptomatology of such injury. It is therefore to be recommended that patients who suffer a head injury should be examined to exclude pituitary gland insufficiency, by measuring the basal hormone level--where necessary in combination with stimulation tests.

Brain Injuries↗
PubMed2004

Gamma knife radiosurgery for nonfunctioning pituitary adenomas.

The efficacy of gamma knife radiosurgery (GKS) for non-functioning pituitary adenomas (NPAs) has been assessed. Sixty patients with NPA were treated by GKS. Complete neurological and endocrinological follow-up information was available for 51 patients. Follow-up examinations included stereotactic magnetic resonance imaging for sequential measurements of the NPA volume. The median dose to the tumor margin was 16.5 Gy (range 11-20 Gy). The mean prescription isodose was 50% (range 45-75%). All patients underwent surgery for NPA before GKS. Fractionated radiotherapy was not applied. Median follow up after GKS was 21,7 months. Actuarial recurrence-free survival was 95% after three years with respect to a single GKS and 100% for patients who underwent repeated GKS. No neurological side effects were detected. Two patients developed new partial pituitary insufficiency after radiosurgery. Postoperative GKS for residual or recurrent small fragments of NPAs is an effective and safe treatment option. The follow-up examination for NPAs should include tumor volumetric analysis.

Actuarial Analysis↗
PubMed2004

Outcome and prognostic factors of hemicraniectomy for space occupying cerebral infarction.

OBJECTIVE: To determine long term functional outcome and length of survival of patients undergoing decompressive craniectomy for space occupying infarction of the middle cerebral artery (MCA), and to identify risk factors associated with death and unfavourable outcomes METHODS: Databases of patients undergoing decompressive craniectomy for space occupying MCA infarction compiled at eight neurosurgical departments (1996-2001) were merged, and 188 patients were evaluated. Mortality was calculated by the Kaplan-Meier method. Clinical outcome was rated using the Glasgow outcome scale (GOS). The prognostic impact of patient related covariates on length of survival and the GOS was analysed multivariately. RESULTS: The unadjusted 3, 6, and 12 month mortality rates were 7.9%, 37.6%, and 43.8%, respectively (median follow up, 26 weeks). In the "best" multivariate model, age >50 years (p<0.02) and the involvement of two or more additional vascular territories (p<0.01) had an unfavourable impact on length of survival. The adjusted six month mortality was as low as 20.0% (no risk factor) and as high as 59.7% (two risk factors). A GOS score of 50 years (p<0.0003): 34.9% of the patients 3, as compared with 12.0% of the elderly subpopulation. The side of the infarct did not have prognostic relevance. CONCLUSIONS: Results of surgical treatment in patients <50 years of age undergoing decompressive craniectomy are encouraging. The effectiveness of decompressive craniectomy for patients >50 years remains questionable and should be analysed in the framework of a prospective randomised study.

Adolescent↗
PubMed2003

Delayed oedema in the pyramidal tracts remote from intracerebral missile path following gunshot injury.

A 60-year-old man developed a severe left hemiparesis and central facial palsy, accompanied by somnolence and dysarthria 9 days after a gunshot wound to the right temporal region, from which he slowly recovered over 3 months. MRI disclosed bilateral oedema of the pyramidal tracts. This was interpreted as a consequence of the impact of the pressure wave caused by the bullet, after excluding an infectious or vascular cause.

Brain Edema↗
PubMed2003

Ruptured intracranial dissecting aneurysms: management considerations with a focus on surgical and endovascular techniques to preserve arterial continuity.

BACKGROUND: The present retrospective analysis was undertaken to review an institutional experience with 13 intracranial dissecting aneurysms as source of subarachnoid haemorrhage (SAH) among a total of 585 ruptured intracranial aneurysms. METHODS AND RESULTS: In 6 patients the vertebral artery (VA) was affected, in 2 patients the basilar artery (BA), in 3 the internal carotid (ICA), in 1 the middle cerebral (MCA) and in 1 the postcommunicating (A2) segment of the anterior cerebral artery (ACA). Maintaining arterial patency was aimed at in all patients. Tangential clipping or circumferential wrapping were used as surgical methods. Endovascular stenting and/or coiling was applied in 2 instances. Four of the 6 VA dissecting aneurysms underwent surgical exploration between 1 and 22 days after haemorrhage. Two patients were in WFNS grade V and died subsequently with the aneurysms untreated, one after rehaemorrhage. In the patients with secured VA aneurysms the postoperative course was uncomplicated with the exception of additional caudal cranial nerve injury in 1 instance. Both BA aneurysms were initially treated by endovascular methods. In the first patient incomplete packing with Gugliemi detachable (GDC) coils was achieved. Follow-up angiography 6 months later showed growth and coil compaction and subsequent wrapping with Teflon fibres resulting in angiographic stabilization. The other BA aneurysm was treated by a combination of a coronary stent and GDC coils. The 3 dissecting ICA aneurysms were all explored surgically. In only 1 instance ICA continuity could be preserved by wrapping, in the other 2 cases a major portion of the vessel wall disintegrated upon removal of the surrounding clot. The only ACA dissecting aneurysm, on A2, was successfully treated with a Dacron cuff. In the single patient with a MCA aneurysm, a decision for conservative management was taken, because neither a surgical nor an endovascular solution was seen as a possibility that did not risk occlusion of lenticulostriate branches. The patient suffered a fatal rehaemorrhage 4 weeks later at her home. CONCLUSIONS: The reported experience suggests that in Western countries also dissecting aneurysms are an occasional source of SAH. The outcome in our conservatively managed patients confirms the poor prognosis of conservative management. Wrapping and endovascular stent based methods can achieve stabilization of the dissected artery without sacrificing the artery. Results of treatment appear to depend largely on the location of the dissecting aneurysm.

Aged↗
PubMed2003

Neuronavigation based on CT angiography for surgery of intracranial aneurysms: primary experience with unruptured aneurysms.

Several reports have demonstrated the use of three-dimensional (3D) computed tomographic angiography (CTA) for preoperative planning in patients with intracranial aneurysms. Until now, there are no reports on the potential role of navigation systems in combination with CTA in aneurysm surgery. In the present study we report our experience with neuronavigation based on CTA in 16 patients with unruptured anterior circulation aneurysms for 1) planning craniotomy; 2) guided approach to the aneurysm; and 3) 3D presentation of the aneurysm and adjacent arteries in correct orientation. The reconstructed CTA images were analyzed preoperatively with regard to diameter of aneurysm neck and dome as well as projection and possible daughter aneurysms, and these parameters were compared with the intraoperative findings. In addition the accuracy of the navigator to locate the aneurysm neck was measured intraoperatively. Navigated approach planning resulted in variable keyhole craniotomies for the 7 middle cerebral artery aneurysms, but did not result in deviation from small standard craniotomies for the internal carotid and anterior communicating artery aneurysms. Precision of the indication of the navigator with regard to the aneurysm neck ranged from < 1 mm to 4 mm. Intraoperative assessment confirmed the CTA data with regard to aneurysm size and projection in all, and definition of daughter aneurysms and adjacent arteries in most cases. The computer assisted approach allowed a smaller, exactly placed craniotomy primarily in MCA aneurysms. 3D presentation of the aneurysms and the adjacent arteries in correct orientation facilitated identification and dissection the aneurysms. Current navigation systems are not precise enough to allow "blind" aneurysm clipping by placing a real clip on the virtual aneurysm neck.

Adult↗
PubMed2002

Effect of C-peptide on wound healing and microcirculation in diabetic mice.

AIM: Recent studies have demonstrated that C-peptide is biologically active and might have a beneficial effect on late complications in diabetes mellitus. The aim of this study was to investigate the effects of systemically given C-peptide on dermal wound healing in diabetic mice. METHODS: Experiments were carried out in male SKH-1 hr hairless mice. Dermal wounds were created (diameter 2.5mm) in streptozotozin-diabetic and normal control mice. Mice were randomized into three treatment groups (n = 10 each): Normal controls, diabetic mice with PBS or C-peptide injection twice daily. At various time points (prior wounding as well as days 4, 7, 10 and 15) microcirculation was quantitatively analyzed by intravital fluorescent microscopy to determine wound surface area, vessel diameter, red blood cell velocity, plasma leakage, functional capillary density. In addition, leukocyte/endothelium interaction was quantified by in vivo visualization of leukocytes. RESULTS: Systemic administration of C-peptide showed no influence on wound healing or standard microcirculatory parameters. The leukocyte/ endothelium interaction revealed a significant (p<0.05) increase in the number of adherent leukocytes 15 days after wound creation in C-peptide treated diabetic mice. CONCLUSION: Except for the significantly increased number of leukocytes adherent to venular endothelium in the C-peptide group no alteration was observed in wound healing and microcirculation. Neutrophil recruitment after C-peptide injection is of interest because it may reduce the risk of infection in diabetes mellitus.

Animals↗
PubMed2001

Ventral discectomy with pmma interbody fusion for cervical disc disease: long-term results in 249 patients.

STUDY DESIGN: Retrospective study of patients who underwent ventral discectomy and polymethyl-methacrylate (PMMA) interbody fusion for cervical radiculopathy. OBJECTIVES: To evaluate the long-term outcome after ventral discectomy and PMMA interbody fusion and to compare it with previous data from other surgical techniques for the treatment of cervical radiculopathy. SUMMARY OF BACKGROUND DATA: Because PMMA interbody fusion after ventral discectomy does not result in solid bony fusion in all cases, a good long-term outcome using this surgical technique has been questioned. METHODS: Long-term follow-up evaluation after surgery was performed in 249 patients (96 women and 153 men) with radicular signs only. The mean age was 46.0 +/- 8.7 years (range, 24-74 years), and the observation time ranged from 10-15 years (mean, 12.2 +/- 1.2 years). Clinical grading after surgery according to Odom's criteria was based on a questionnaire. The outcome was related to morphologic findings, lumbar symptoms, physical stress, duration of symptoms, age, sex, and cervical level involved. RESULTS: Complications related to surgery occurred in 13 (5.2%) patients, but only three (1.2%) had persistent problems. Of the 249 patients, 101 (40.6%) were without any symptoms (Odom I), 92 (36.9%) had a good outcome (Odom II), and 47 (18.9%) a fair outcome (Odom III). Only nine patients (3.6%) reported an unchanged or worse status than before surgery (Odom IV). Additional lumbar symptoms, high occupational physical stress, and discrepancy of preoperative findings were significantly correlated with a worse outcome. Short duration of symptoms and soft disc disease were favorable prognostic factors. CONCLUSIONS: PMMA interbody fusion after ventral discectomy in cervical disc surgery is a safe and reliable method with few complications and an outcome comparable with other ventral procedures.

Adult↗
PubMed2001

Transorbital keyhole approach to anterior communicating artery aneurysms.

OBJECTIVE: The transorbital keyhole approach to anterior communicating artery aneurysms was developed as a minimally invasive method for safe control of the anterior communicating artery complex. This approach does not necessitate resection of the gyrus rectus. METHODS: The technique is described in detail. The transorbital keyhole approach provides more ventral access than the supraorbital approaches, and the anterior communicating artery complex can be controlled by splitting the basal aspect of the interhemispheric fissure. RESULTS: Since late 1998, the authors have used the transorbital keyhole approach routinely. During the initial experience with 33 patients, the only observed complication specific to this approach was transient diplopia in one patient. At follow-up examinations 2 to 15 months after surgery, the cosmetic results were favorable as compared with those of standard pterional craniotomy. CONCLUSION: We have designed a small, custom-tailored approach to the anterior communicating artery complex for routine use. The small orbitocranial approach is a step toward the ideal of purely extra-axial safe control of anterior communicating artery aneurysms. The orbitocranial keyhole approach seems to be substantially better than the craniotomy, although it requires additional effort and time.

Esthetics↗
PubMed2001

M2/M2 side-to-side rescue anastomosis for accidental M2 trunk occlusion during middle cerebral artery aneurysm clipping: technical note.

OBJECTIVE: A technically feasible and rapid technique for revascularizing the main branches of the middle cerebral artery (MCA) is described. This technique is applied mainly when clipping of an MCA aneurysm is complicated and occlusion of the origin of an MCA main branch results. METHODS: M2/M2 side-to-side anastomosis was applied in two patients in whom unplanned M2 occlusion occurred during the course of complicated MCA aneurysm clipping. The first patient underwent an emergency procedure after temporoparietal intracerebral hemorrhage. Unilateral mydriasis precluded preoperative angiographic workup, and a complex large MCA aneurysm was found as the source of hemorrhage. Shaping of the aneurysm neck by bipolar coagulation and clipping resulted in accidental occlusion of the superior trunk, and patency could not be regained despite multiple clip corrections. The second patient had an unruptured multilobulated aneurysm 8 mm in maximum diameter. Continuity of the inferior trunk was lost during clipping because of a tear at the origin. In both instances, side-to-side anastomosis was placed approximately 15 mm from the bifurcation, where the MCA main trunks ran side by side for a length of approximately 5 mm. RESULTS: After intracerebral hemorrhage, the first patient recovered to a level of moderate disability within 2 months. Substantial hemiparesis and expressive dysphasia remained as sequelae of the intracerebral hemorrhage. Digital subtraction angiography 2 months after the emergency procedure confirmed patency of the side-to-side anastomosis. The second patient was neurologically intact after recovery from anesthesia. Before discharge from the hospital on postoperative Day 8, digital subtraction angiography confirmed patency of the anastomosis. CONCLUSION: The MCA main branches usually run in close proximity for a short segment at the bottleneck entrance to the insular cistern. M2/M2 side-to-side anastomosis at this site is a rapid and feasible mode of revascularization of an M2 trunk accidentally occluded during complicated MCA aneurysm clipping.

Adult↗
PubMed2001

Vascular endothelial growth factor production and regulation in rodent and human pituitary tumor cells in vitro.

Angiogenesis, the formation of a new blood supply, is an essential step in tumorigenesis. Although vascular endothelial growth factor (VEGF) is known to be a very potent angiogenic factor in most solid tumors, little is known about its production and regulation in pituitary adenomas. We have investigated basal and stimulated VEGF production by rodent pituitary tumor cells (mouse corticotrope AtT20, rat lactosomatotrope GH3, mouse gonadotrope alpha T3-1 and mouse folliculostellate TtT/GF cells), and by hormone-inactive (27), corticotrope (9), lactotrope (3) and somatotrope (21) human pituitary adenoma cell cultures. All 4 pituitary cell lines secreted VEGF, which in the case of AtT20, GH3 and TtT/GF cells was inhibited by approximately 50% by dexamethasone. TtT/GF cells were the most responsive to the different stimuli used since basal values were augmented by pituitary adenylate cyclase activating polypeptide-38 (PACAP-38), interleukin-6 (IL-6), transforming growth factor-alpha (TGF-alpha), IGF-I and the somatostatin analogue ocreotide. However, in GH3, AtT20 and alpha T3-1 cells, basal VEGF levels where not enhanced with any of the stimuli tested. The majority of the human adenomas tested (92%) basally secreted measurable VEGF which was inhibited by dexamethasone in most cases (84%). VEGF levels were increased in hormone inactive adenomas, somatotrope tumors and prolactinomas by TGF-alpha, PACAP-38, and 17 beta-estradiol, respectively. In conclusion, pituitary tumor cells are capable of producing VEGF which may be involved in tumoral angiogenesis. Our results concerning the suppression of VEGF by dexamethasone suggest that glucocorticoids may have anti-angiogenic properties and therefore therapeutic relevance for the treatment of pituitary adenomas.

Adenoma↗