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Biomedical subjects

M Weisskopf

Publications and source records attributed to M Weisskopf.

At least 19 recordsLinked to original sources
PubMed2005

A Vitex agnus-castus extract inhibits cell growth and induces apoptosis in prostate epithelial cell lines.

Extracts of Vitex agnus-castus fruits (VACF) are described to have beneficial effects on disorders related to hyperprolactinemia (cycle disorders, premenstrual syndrome). A VACF extract has recently been shown to exhibit antitumor activities in different human cancer cell lines. In the present study, we explored the antiproliferative effects of a VACF extract with a particular focus on apoptosis-inducing and potential cytotoxic effects. Three different human prostate epithelial cell lines (BPH-1, LNCaP, PC-3) representing different disease stages and androgen responsiveness were chosen. The action of VACF on cell viability was assessed using the WST-8-tetrazolium assay. Cell proliferation in cells receiving VACF alone or in combination with a pan-caspase inhibitor (Z-VAD-fmk) was quantified using a Crystal Violet assay. Flow cytometric cell cycle analysis and measurement of DNA fragmentation using an ELISA method were used for studying the induction of apoptosis. Lactate dehydrogenase (LDH) activity was determined as a marker of cytotoxicity. The extract inhibited proliferation of all three cell lines in a concentration-dependent manner with IC (50) values below 10 microg/mL after treatment for 48 h. Cell cycle analysis and DNA fragmentation assays suggest that part of the cells were undergoing apoptosis. The VACF-induced decrease in cell number was partially inhibited by Z-VAD-fmk, indicating a caspase-dependent apoptotic cell death. However, the concentration-dependent LDH activity of VACF treated cells indicated cytotoxic effects as well. These data suggest that VACF contains components that inhibit proliferation and induce apoptosis in human prostate epithelial cell lines. The extract may be useful for the prevention and/or treatment not only of benign prostatic hyperplasia but also of human prostate cancer.

Antineoplastic Agents, Phytogenic↗
PubMed2001

CT scans versus conventional tomography in acute fractures of the odontoid process.

Four different radiological diagnostic methods were compared as to their diagnostic relevance in the analysis of odontoid fractures. Thirty-one patients with fresh odontoid fractures were investigated using standard anteroposterior and lateral radiographs, conventional tomography, axial computerized tomography and two-dimensional reconstruction in the sagittal and the coronal planes. As a control, 13 patients without odontoid fractures were examined. The results of the different investigations were correlated with the actual (clinical and/or intra-operative) findings. The coefficients of correlation for the conventional tomography and two-dimensional reconstruction were kappa=0.774 and kappa=0.907, respectively. For conventional radiography and axial computerized tomography (CT), the coefficients were clearly lower, at kappa=0.364 and kappa=0.627, respectively. The less time-consuming CT examination with sagittal and coronal reconstructions is equivalent with respect to diagnostic accuracy and can, therefore, replace conventional tomography in the evaluation fractures.

Acute Disease↗
PubMed2001

Smoking during pregnancy in Wisconsin compared to the United States, 1997.

PURPOSE: The purpose of this study is to identify disparities in maternal smoking between Wisconsin and United States women and to determine differences that explain the higher percentage of pregnant women who smoke in Wisconsin compared to the United States. METHODS: 1997 Wisconsin and US birth certificate data were compared and stratified by age, education, and race/ethnicity. The relative risks (the risk of Wisconsin women smoking during pregnancy compared to US women smoking during pregnancy) were calculated by direct standardization to the 1997 US distribution for these characteristics. RESULTS: In 1997, 17.9% of Wisconsin women smoked during pregnancy, compared with 13.2% nationally (relative risk [RR] = 1.4; Wisconsin women were 40% more likely to smoke than US women). Age and education adjusted RRs among Wisconsin women aged 20 and older were 2.3 (American Indian), 2.8 (Hispanic), and 2.2 (non-Hispanic black), while the RR was 1.2 for non-Hispanic white mothers. Among women 20 and older, the crude RR for Wisconsin was 1.5; adjusting for age, education, and race/ethnicity only slightly decreased the RR to 1.4. CONCLUSIONS: The percentage of women who smoke during pregnancy in Wisconsin continues to be above the national rate and the Healthy People 2000 goal of 10% or less. Disparities with the US average are particularly great for minority women in Wisconsin. Adjusting for age, education and ethnicity does not explain Wisconsin's higher prenatal smoking rate.

Adolescent↗
PubMed1999

Bisegmental rotational fracture dislocation of the pediatric cervical spine. A case report.

STUDY DESIGN: A case of a bisegmental rotational fracture dislocation in the pediatric cervical spine is presented. OBJECTIVES: To highlight the problems in the diagnostics and surgical management of this rare type of injury. SUMMARY OF BACKGROUND DATA: Fractures of the cervical spine are relatively uncommon in childhood. To the authors' knowledge, this is the first reported case of a bisegmental rotational fracture dislocation in the pediatric cervical spine managed by a combined anteroposterior approach. METHODS: A 6-year-old girl was hit by a car as a pedestrian. In addition to an open fracture dislocation of the Lisfranc joint in the right foot, she sustained a bisegmental fracture dislocation at the lower cervical spine (C3-C5) with no neurologic deficit. The complete diagnosis of a locked rotational fracture dislocation could be established only by using computed tomography scans with three-dimensional reconstructions. The injury was managed with a combined anteroposterior open reduction and a bisegmental anterior fusion. RESULTS: Implant removal was performed after bony fusion 6 months after surgery. At follow-up assessment 2.5 years later, the girl had a good radiologic result and a full and pain-free functional recovery. CONCLUSIONS: Bisegmental rotational fracture dislocations in pediatric cervical spines are not easily diagnosed and may require three-dimensional computed tomography scan reconstructions for complete assessment. In such rare cases, a combined anteroposterior surgical procedure may be indicated, with a bisegmental anterior fusion providing a good functional result.

Bone Plates↗
PubMed1999

[Fixed rotatory subluxation of the atlanto-axial joint in polytrauma patients].

Traumatic atlanto-axial instabilities are rare entities in cervical spine injuries. There may be only subtle abnormal findings by plain radiographs, frequently resulting in a missed or delayed diagnosis. We report a polytraumatized patient with severe maxillofacial injuries, where preliminary radiological studies failed to verify rotatory instability of the atlanto-axial joint. A definite diagnosis was only established by further imaging studies, including CT scan reformations.

Adolescent↗
PubMed1999

[Value of MRI in traumatic disco-ligament instability of the lower cervical spine].

The diagnostic accuracy of magnetic resonance imaging (MRI) for traumatic discoligamentous instabilities of the lower cervical spine was evaluated. MRI findings were correlated with the intraoperative findings. Fifteen patients were included in the study (11 males, 4 females, 33 years old on average). Indication for surgery was established with dynamic a.p. instability under fluoroscopy. In the operation, all patients showed complete traumatic rupture of the intervertebral disc. In contrast, MRI sequences revealed only eight mild and four severe disc lesions. Intraoperatively ruptures of the anterior and posterior longitudinal ligaments were verified in 7 patients each. MRI studies depicted only five ruptures of the anterior and three ruptures of the posterior longitudinal ligaments. In three cases MRI demonstrated no pathological findings (3 of 15 false-negative results). MRI and intraoperative findings showed no statistical correlation. MRI is of only limited value in diagnosing traumatic discoligamentous instabilities of the lower cervical spine.

Adolescent↗
PubMed1998

[Dorsal removal and stabilization of giant cell tumor of the thoracic spine].

The incidence of giant cell tumors accounts for less than 5% of all bone tumors. In the thoracic spine these tumors are extremely rare (1-1.5% of the giant-cell tumors). The potential malignant character of giant cell tumors of the spine usually leads to wide surgical extirpation by ventral approach. The filling of bone defects with palacos cement after tumor resection is sufficient in the metaphysis of long bones. The case presented here is a giant cell tumor of the upper thoracic spine with primarily posterior destruction of the vertebral body and left arch. A single dorsal approach allowed for intralesional resection and filling of the defect with bone cement. This procedure was sufficient to achieve a solid fixation without recurrence of the giant cell tumor.

Adolescent↗
PubMed1996

[Dens fracture and multiple fracture of the thoracic spine after fall from great height. Diagnostic standard].

Multiple level spine fractures after a fall from a great height frequently cause a neurological deficit with paraplegia. In general, survival after a free fall from 20 m height without any neurological deficit is very unlikely. Since a considerable part of the trauma may not be detected by conventional radiograms, it is recommended that CT scans of all affected spine regions always be carried out with 2 D reconstructions. In addition, 3 D reconstructions should be performed if rotatory instability is suspected. This case report illustrates the management and diagnostic problems of a serial spine trauma.

Accidental Falls↗
PubMed1994

Night sleep does not predict day sleep in narcolepsy.

It has been suggested that the increased day sleep in narcolepsy-cataplexy is secondary to the known fragmentation and reduction of night sleep, there being no differences in 24 h sleep totals from normals. Twenty-two untreated patients underwent 24 h sleep wake recordings by ambulatory monitoring. Correlations were assessed by stepwise multiple regression between day sleep and night sleep measures. Almost no significant or near significant correlations emerged. It is concluded that day sleep in narcolepsy is based upon a different mechanism, perhaps a diurnal "subvigilance syndrome" of impaired arousal mechanisms.

Adult↗
PubMed1991

Neurons with callosal projections in visual areas of newborn kittens: an analysis of their dendritic phenotype with respect to the fate of the callosal axon and of its target.

Combined retrograde transport of Rhodamine-labeled latex beads and intracellular injection of Lucifer Yellow in aldehyde-fixed slices of areas 17 and 18 in kittens indicate that neurons with similar dendritic morphology send axons into the corpus callosum from the 17/18 border and from parts of area 17 destined to become acallosal. At both sites callosally projecting neurons (callosal neurons) include pyramids, spiny stellate cells and star-pyramids; two types of pyramidal neurons can be distinguished on the basis of the complexity of their apical dendrites. At both sites, the dendritic morphology of callosal neurons appears basically unaffected by the ablation at the beginning of the second postnatal week of the contralateral areas 17 and 18 to which they have sent their axon. Thus the dendritic morphology of this type of cortical neuron seems independent of retrograde signals coming from their contralateral target and may instead depend on "programs" intrinsic to the neurons and/or conditions acting locally on their cell bodies, dendrites or initial axon collaterals.

Animals↗
PubMedDate not supplied

[Comparative analysis of lumbar spine degeneration documented by x-rays versus large specimen cryomicrotome sections].

AIM OF THE STUDY: The extent of degenerative changes in the lumbar spine as seen on conventional radiographs is interpreted on the basis of visualized osseus structures and indirect signs such as diminution of disc height. In order to analyze the accuracy of these interpretations we compared and correlated different stages of degeneration in conventional radiographs with cuts of large-specimen cryomicrotome sections (LSCS), offering a direct macroscopic vision of the degenerative anatomic features. METHOD: A total of 50 human cadaver lumbar spines with 251 spine segments (Th 12 - S1) was investigated by plain radiograms and LSCS. The degenerative changes were differentiated into 5 stages for both diagnostic measures. Criteria for radiological degeneration were: diminution of disc space, presence of osteophytes and sclerosis of the endplates. Degenerative changes as seen by LSCS were evaluated by the following features: cracks in the endplate, bleeding into the intervertebral disc, alignment of the annulus fibrosus fibres and osseous alterations in the spine segment. RESULTS: Complete matches of the evaluated radiological and macroscopic stages of degeneration were observed in 206 cases. A difference of 1 degree on the degeneration scale was registered in 42 segments, whereas a difference of 2 degrees was seen in 3 cases. The correlation coefficient between the degeneration stages of the two diagnostic measures scored rho = 0.883. CONCLUSION: The comparison of the different degrees of degeneration in the lumbar spine as evaluated by both plain radiographs and LSCS revealed a good correlation.

Adolescent↗
PubMedDate not supplied

[Kyphoplasty - a new minimally invasive treatment for repositioning and stabilising vertebral bodies].

AIM OF THE STUDY: Osteoporotic vertebral fractures are an ailment of the aging population of increasing incidence and high socioeconomic impact. Intractable pain causing significant morbidity leads to long-term hospitalisation. Kyphoplasty offers a new minimal invasive operative stabilisation procedure for these vertebral compression fractures. This study is conducted to investigate whether this procedure significantly reduces both pain and the duration of hospital stay in comparison to conservative treatment modalities. METHOD: From January until July 2002 a total of 22 patients had undergone kyphoplasty in 37 vertebral bodies. Osteoporotic vertebral fractures were treated in 18 cases, while in another 4 cases prophylactic stabilisation for osteolytic lesions was performed. Both the duration of hospital stay and the reduction of pain symptoms were determined and compared to a conservatively treated control group of 20 patients suffering from 35 fractured vertebral bodies. Pre- and postoperative endplate angles were measured to assess the restoration of the sagittal alignment. The effects on pain symptoms were measured on a self-reported Visual Analogue Score Scale. RESULTS: The mean pain relief for the patients undergoing kyphoplasty was 82 %, which was significantly higher (p < 0.0001) compared to the group of the conservatively treated patients (42 %). Reduction of the kyphotic deformity was achieved in 4 cases (average 8.5 degrees ). The average in-patient treatment duration for the surgical treated patients was 10 days as opposed to a significantly longer mean hospitalisation of 20 days (p = 0.003). Cement extravasation was observed in 5 out of 37 treated vertebral bodies without clinical sequelae. CONCLUSION: Kyphoplasty is a safe minimal invasive procedure for the stabilisation of osteoporotic vertebral fractures leading to a statistically significant reduction both of pain status and duration of hospitalisation.

Aged↗
PubMedDate not supplied

[Correlation of low back pain and enhanced vascularization in the vertebral endplate].

AIM OF THE STUDY: Degenerative changes of the motion segments are accompanied by an increased vascularization of the endplates. Nerve elements have been demonstrated in the environment of the endplate vessels, which might play a role in pressure related pain sensation. In order to investigate this theory we compared and correlated the extent of memory pain as determined by discography with the amount of vascularization in the endplates on histological examination. METHOD: Discography was performed in 32 Patients (21 female, 11 male), who underwent spinal fusion. The extent of pain sensation was determined on a self reported visual analogue scale ranging from 0-10 Points. Bone chips from the anterior vertebral endplates were obtained during surgery. Decalcified paraffin-embedded samples were then immunostained with the vascular endothelial marker CD 34. The quantification of endothelium as part of the whole cross section area was performed by means of a computerized optical method. RESULTS: The extent of the pain sensation during discography ranged from 0-9 points on the VAS (average: 5.3 points, SD 3.1). On the histological quantification the total endothelial area per observed field varied from 0.04 to 7.39 % (average: 2.19 %, SD 1.62). The comparison of the pain extent on discography and the vascularization of the endplate resulted in a correlation coefficient after Spearman of rho = + 0.64 (p=0.0006). CONCLUSION: The extent of vascularization in the degenerated endplates of a motion segment shows a moderate correlation with the self reported VAS scores after discography. Further investigations will have to clarify, whether neurogenic structures originating from vascular endothelium yield a better correlation to discogenic pain.

Endothelium, Vascular↗
PubMedDate not supplied

[The cement-free modular revision prosthesis MRP-hip revision stem prosthesis in clinical follow-up].

INTRODUCTION: We present prospective medium-term results of the modular revision prostheses "MRP-TITANIUM". MATERIAL AND METHODS: 45 patients (n = 48 prostheses) were evaluated. The mean follow-up was 4.7 years (min.-max.: 1.0-9.0 years). Pre- and postoperatively the Harris hip score (differentiated to Paprosky I-III) was examined. 66.67 % of the cases had extensive bony defects (> or = Paprosky II b). By means of X-ray examinations, the stability of the prostheses, periprosthetic bone remodelling, the presence of radiolucent lines as well as bone defect regeneration were assessed postoperatively. RESULTS: The mean Harris hip score improved from 25.6 preoperative to 71.4 postoperative (p < or = 0.05). In 44 cases the X-ray showed stable fixation without secondary migration. In one case the stem (stand time 2.36 years) was revised due to secondary migration (> or = 5 mm). The survival rate (Kaplan-Meier) was 97 %. Bone transplantation with consecutive defect regeneration was (n = 30) complete in all cases. In six cases (12.5 %) a postoperative dislocation occurred with subsequent successful closed reposition four times (8.3 %). In two cases (4.2 %) an open reposition was done with correction of the antetorsion angle of the prostheses. CONCLUSION: The "MRP-TITANIUM modular revision prostheses" has proved to be reliable in cases of revision surgery with extensive bony defects. The failure rate was 2.1 % for 48 prospectively examined prostheses.

Aged↗
PubMedDate not supplied

[Minimally-invasive computer-assisted fluoroscopic navigation for kyphoplasty].

AIM: The transpedicular placement of a hollow needle into vertebral bodies for kyphoplasty requires utmost accuracy and thereby permanent multiplanar X-ray control. Facing the increasing number of vertebral compression fractures, the aim of this work was the implementation of computer-assistance to optimise the issue. Prior to clinical implementation, experimental trials were undertaken to analyse the quality-improving options of the technique. METHOD: The virtual image of the planning and the puncture were correlated with the postoperative X-ray image of the needle. The real canal in the bone was then correlated with the preoperative planning in a CT-based 3D model and differences were calculated. As a measure of accuracy the deviation of the needle from the ideal intruding vector and the distance between its top and the centre of a predefined target were scrutinised and related to the indications of the navigation system. Operating time, radiation exposure and general applicability were additionally assessed. All data were compared with those of a conventional control group. RESULTS: Planning and navigation could be executed with high accuracy. With an exactly transpedicular approach, neural structures were safely circumnavigated without once missing the target. In the control group the distance fault was up to 9 mm. The navigated drilling differed from the ideal trajectory by 1 degrees to max. 4 degrees. Conventional C-arm control led to a divergence of 4 degrees to 8 degrees . Radiation exposure could be reduced through computer assistance by 76 % to a fourth of the conventionally resulting amount and the pure operating time thereby decreased by 40 %. The inconvenient course of repeated positioning of the C-arm was overcome. CONCLUSION: In challenging cases of deteriorated anatomy and difficult radiomorphologic orientation, especially of the lower thoracic spine, the CAOS-procedure succeeds in finding the optimal pedicular approach to the vertebral body, helps to avoid collateral damage and minimises the overall risk of the procedure. High accuracy and reduced radiation exposure justify the clinical use of fluoroscopic navigation for transpedicular instrumentation.

Decompression, Surgical↗
PubMedDate not supplied

[epiDRB--a new minimally invasive concept for referencing in the field of computer-assisted orthopaedic surgery].

AIM: Optoelectronic navigation for computer-assisted orthopaedic surgery (CAOS) is based on a firm connection of bone with passive reflectors or active light-emitting diodes in a specific three-dimensional pattern. Even a so-called "minimally-invasive" dynamic reference base (DRB) requires fixation with screws or clamps via incision of the skin. Consequently an originally percutaneous intervention would unnecessarily be extended to an open procedure. Thus, computer-assisted navigation is rarely applied. Due to their tree-like design most DRB's interfere with the surgeon's actions and therefore are at permanent risk to be accidentally dislocated. Accordingly, the optic communication between the camera and the operative site may repeatedly be interrupted. The aim of the research was the development of a less bulky, more comfortable, stable and safely trackable device that can be fixed truly percutaneously. METHOD: With engineering support of the industrial partner the radiolucent epiDRB was developed. It can be fixed with two or more pins and gains additional stability from its epicutaneous position. The intraoperative applicability and reliability was experimentally tested. RESULTS: Its low centre of gravity and its flat design allow the device to be located directly in the area of interest. Thanks to its epicutaneous position and its particular shape the epiDRB may perpetually be tracked by the navigation system without hindering the surgeon's actions. Hence, the risk of being displaced by accident is minimised and the line of sight remains unaffected. CONCLUSION: With the newly developed epiDRB computer-assisted navigation becomes easier and safer to handle even in punctures and other percutaneous procedures at the spine as much as at the extremities without an unproportionate amount of additional trauma. Due to the special design referencing of more than one vertebral body is possible at one time, thus decreasing radiation exposure and increasing efficiency.

Equipment Design↗