Immunohistochemical localization of neurofilaments and neuron-specific enolase in 29 cases of neuroblastoma.

Twenty-nine neuroblastomas have been examined with the use of rabbit antibodies specific for each of the three neurofilament polypeptides, with a monoclonal antibody specific for the NF-L polypeptide, and with a rabbit antibody specific for neuron-specific enolase. When frozen material was used, all neuroblastomas were positive with the neurofilaments antibodies. When alcohol-fixed paraffin-embedded material was used, neurofilament staining was weaker and the fixation procedure appeared to destroy the epitopes recognized by the NF-L antibodies preferentially. Although all neuroblastomas were positive for neurone-specific enolase, so were two rhabdomyosarcomas, suggesting that NSE is not an appropriate marker to distinguish the different small blue cell tumors of children.     

Parasympathetic non-adrenergic, non-cholinergic-induced protein synthesis and mitogenic activity in rat parotid glands

Electrical stimulation of the parasympathetic auriculo-temporal nerve (40 Hz, 30 min), in the anaesthetized rat under - and -adrenoceptor blockade, increased [3H]thymidine and [3H]leucine uptake into the parotid glands by 80 and 263 %, respectively. The increase in response to parasympathetic stimulation was almost the same ([3H]thymidine 82 % and [3H]leucine 283 %) when atropine (2 mg kg-1 I.P. or I.V.) was included in the pretreatment. Neither intravenous infusion of vasoactive intestinal peptide (0.5-20 mg kg-1 min-1, 30 min) nor of bethanechol (10 mg kg-1 min-1, 30 min), under adrenoceptor blockade, increased the uptake of [3H]thymidine into the glands. However, these drugs increased [3H]leucine uptake, and in combination they interacted positively. Whereas vasoactive intestinal peptide is likely to be involved in the parasympathetic nerve-evoked protein synthesis, the nature of the non-adrenergic, non-cholinergic component(s) involved in the mitogenic response is presently unknown.     

Numerical chromosomal aberrations in prostate cancer: correlation with morphology and cell kinetics

Eleven routinely processed radical prostatectomy specimens were studied for the presence of numerical chromosomal aberrations by means of in situ hybridization with nucleic acid probes specific for chromosomes 7, 10, 17, X, and Y. Cytogenetic information was correlated with morphology, tumour stage and volume as well as with cell kinetics, the latter being assessed by immunohistochemistry with antibodies raised against the proliferative cell nuclear antigen (PCNA) and against a formalin-resistant epitope of the Ki-67 antigen, MIB 1. In 5 of 11 cases, numerical aberrations of at least one chromosome were found. The cases with normal chromosome numbers were those with the smallest volumes of Gleason grade 4 and/or 5 tumour (mean 0.5 cm³) and represented tumours restricted to the prostate. Tumours with aberrations in the number of detected chromosomes showed advanced stages and large volumes of high-grade tumour (mean 12.5 cm³). All 4 tumours with positive surgical margins were recruited from a group with marked local heterogeneity in chromosome numbers. Immunostaining with MIB 1 and PCNA was most intense in areas of high-grade tumour and was positively correlated with the emergence of chromosomal aberrations. The data suggest that the appearance of numerical chromosomal aberrations in prostate cancer coincides with aggressive tumour behaviour and could be used as an additional prognostic marker.This work is part of E.K.'s doctoral thesis     

Variable selection under multiple imputation using the bootstrap in a prognostic study

Background  

Missing data is a challenging problem in many prognostic studies. Multiple imputation (MI) accounts for imputation uncertainty that allows for adequate statistical testing. We developed and tested a methodology combining MI with bootstrapping techniques for studying prognostic variable selection.     

Extrinsic risk factors for compromised blood flow in the vertebral artery: anatomical observations of the transverse foramina from C3 to C7

The vertebral artery (VA) is often involved in the occurrence of complications after spinal manipulative therapy. Due to osteophytes compressing the VA anteriorly from the uncinate process or posteriorly from the facet complex, the VAs are susceptible to trauma in the transverse foramina. Such altered anatomical configurations are of major clinical significance, as spinal manipulations may result in dissection of the VA with serious consequences for the blood supply to the vertebrobasilar region. The purpose of this study is to describe numerous structural features of the third to seventh cervical vertebrae in order to contribute to the understanding of pathological conditions related to the VA. The minimal and maximal diameter of 111 transverse foramina in dry cervical vertebrae were studied. The presence of osteophytes and their influence on the VA were evaluated at the vertebral body and at the superior and inferior articular facets. The diameter of the transverse foramina increased from C3 to C6, while the transverse foramina of C7 had the smallest diameter. At all levels the mean dimensions of the left foramina were greater than those of the right side. Osteophytes from the uncinate process of C5 and C6 vertebrae were found in over 60% of dry vertebrae. Osteophytes from the zygapophyseal joints were more frequent at C3 and C4 vertebrae. About half of the osteophytes of the uncinate and of the superior articular process partially covered the transverse foramina. This was less common with those of the inferior articular facets. Osteophytes covering the transverse foramen force the VAs to meander around these obstructions, causing narrowing through external compression and are potential sites of trauma to the VAs potentially even leading to dissection. We strongly advocate that screening protocols for vertebrobasilar insufficiency (VBI) be used prior to any manipulation of the cervical spine and should include not only extension and rotation but any starting position from which the planned manipulation will be performed.     

Comparison of edge analysis techniques for the determination of the MTF of digital radiographic systems

The modulation transfer function (MTF) is well established as a metric to characterize the resolution performance of a digital radiographic system. Implemented by various laboratories, the edge technique is currently the most widespread approach to measure the MTF. However, there can be differences in the results attributed to differences in the analysis technique employed. The objective of this study was to determine whether comparable results can be obtained from different algorithms processing identical images representative of those of current digital radiographic systems. Five laboratories participated in a round-robin evaluation of six different algorithms including one prescribed in the International Electrotechnical Commission (IEC) 62220-1 standard. The algorithms were applied to two synthetic and 12 real edge images from different digital radiographic systems including CR, and direct- and indirect-conversion detector systems. The results were analysed in terms of variability as well as accuracy of the resulting presampled MTFs. The results indicated that differences between the individual MTFs and the mean MTF were largely below 0.02. In the case of the two simulated edge images, all algorithms yielded similar results within 0.01 of the expected true MTF. The findings indicated that all algorithms tested in this round-robin evaluation, including the IEC-prescribed algorithm, were suitable for accurate MTF determination from edge images, provided the images are not excessively noisy. The agreement of the MTF results was judged sufficient for the measurement of the MTF necessary for the determination of the DQE.     

Target motion measurement without implanted markers and its validation by comparison with manually obtained data

For an effective radiotherapy the exact tumor location must be determined. The localization has to take into account patient's setup position as well as internal organ motion. Among the different localization methods, the use of a computer tomography (CT) scanner in the therapy room has been proposed recently. Achieving a CT with the patient on the therapy couch, a patient's treatment position is captured. We present a method to locate tumor considering internal organ motion and displacements due to respiration. We tested the method with prostate and lung patients. The method found the most probable tumor position as well as, for high-mobility tumors located in the lung, its trajectory during the respiratory cycle. The results of this novel method were validated by comparison with manually determined target position.