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Although many studies have focused on the importance of littering and (or) illegal dumping as a source of plastic pollution to freshwater, other relevant pathways should be considered, including wastewater, stormwater runoff, industrial effluent/runoff, and agricultural runoff. Here, we conducted a meta-analysis focused on these four pathways. We quantified the number of studies, amount and characteristics of microplastics reported, and the methods used to sample and measure microplastics from each pathway. Overall, we found 121 studies relevant to our criteria, published from 2014 to 2020. Of these, 54 (45%) quantified and characterized microplastics in discharge pathways. Although most focused on wastewater treatment plant effluent (85%), microplastic concentrations were highest in stormwater runoff (0.009 to 3862 particles/L). Morphologies of particles varied among pathways and sampling methods. For example, stormwater runoff was the only pathway with rubbery particles. When assessing methods, our analysis suggested that water filtered through a finer (

Success in locomotor rehabilitation programs can be improved with the use of brain-computer interfaces (BCIs). Although a wealth of research has demonstrated that locomotion is largely controlled by spinal mechanisms, the brain is of utmost importance in monitoring locomotor patterns and therefore contains information regarding central pattern generation functioning. In addition, there is also a tight coordination between the upper and lower limbs, which can also be useful in controlling locomotion. The current paper critically investigates different approaches that are applicable to this field: the use of electroencephalogram (EEG), upper limb electromyogram (EMG), or a hybrid of the two neurophysiological signals to control assistive exoskeletons used in locomotion based on programmable central pattern generators (PCPGs) or dynamic recurrent neural networks (DRNNs). Plantar surface tactile stimulation devices combined with virtual reality may provide the sensation of walking while in a supine position for use of training brain signals generated during locomotion. These methods may exploit mechanisms of brain plasticity and assist in the neurorehabilitation of gait in a variety of clinical conditions, including stroke, spinal trauma, multiple sclerosis, and cerebral palsy.

Objectives: The study investigated the impact of occupational workloads on disc surgery specimens. We report the relationship between workload and histological features., Methods: Specimens were collected prospectively from patients suffering from lumbar disc prolapse (n=90) or spinal osteochondrosis (n=19). Histomorphology and occupational workload data and histomorphological features were evaluated. Occupational data were collected in a structured, standardized patient interview assessing lifting and carrying loads. In this way the exposure was assessed for each test subject's entire working life up to surgery., Results: There was no association between cumulative workload and histological patterns. In a subgroup of patients with a workload period of 12 months prior to surgery a relevant formation of chondrocyte clusters (p=0.055) was apparent. Chondrocyte cluster formation was found in 83% (n=74) of the prolapse patients and in 58% (n=11) of the osteochondrosis patients (p=0.02). Fibrocyte mediated scar formation was found in 55% of the prolapse patients and in 45% of the spinal stenosis patients. Chondrocyte clusters and their de novo collagen matrix did not integrate biomechanically sufficient with collagen fibers of the disc. Disintegration of clusters from disc matrix and formation of intra-discal sequesters were observed., Conclusion: Matrix degeneration was common but displayed no relationship to occupational workload or other histological features. Scar formation was observed in every second specimen. Regenerative chondrocyte cluster proliferation was a common feature in disc specimens and tended to be associated in patients with a workload one year before surgery.

Study Design: Experimental study., Objective: It was aimed to establish a cadaver model to imitate osteoporotic perfused vertebral bone and to allow for transpedicular transfer of bone cement and various new materials into vertebrae. The model was perfused to simulate vertebroplasty in the presence of transvertebral blood flow., Summary of Background Data: The injection of bone cement into vertebrae bears the risk of irreversible discharge of material into the venous system of the spinal canal. The bovine cadaver model studied allows visual studies of material distribution in a vertebral bone, the potential spill-out of material, and quantification of washout and disintegration phenomena., Methods: Thoracic and lumbar vertebrae from 1-year-old calves were cut transversally into 5 mm slices, macerated, and decalcified. The softened bone slices were compressed between 2 transparent plastic discs. A standard vertebroplasty cannula (outer diameter 3.5 mm, inner diameter 2.5 mm) was inserted into the vertebral body via the pedicle to transfer the different vertebroplasty materials. Arterial blood flow was simulated by means of liquid irrigation via 2 needles in the ventral part of the vertebral body slice. Metal powder was mixed with the solution to indicate the blood flow in the bone. The model was evaluated with the vertebroplasty cement polymethylmethacrylate., Results: The model permitted visualization of the insertion and distribution of vertebroplasty materials. Liquid bone cement was effused into the spinal canal as in the clinical situation. Higher modulus cement acted in the same way as in clinical vertebroplasty. Rigid vertebroplasty agents led to trabecular fractures and stable mechanical interactions with the bone and eventually moved dorsal bone fragments into the spinal canal. Sedimentation of the metal powder indicated regions of perfusion., Conclusion: The model simulated the clinical behavior of liquid and higher modulus vertebroplasty agents in the presence of blood flow. It enabled safe ex vivo testing of the mechanical and physical properties of alternative vertebroplasty materials under flow conditions.

Objective: The study presented evaluated the first clinical use of a new multiparameter catheter measuring intracranial pressure (ICP), partial pressure of brain tissue oxygen (ptiO2), and brain temperature (TBr) (Neurovent PTO). To assess the validity of measured ptiO2 a second probe, which represents the current golden standard of ptiO2 measurement, was implanted (Licox system)., Methods: Thirty patients with indicated invasive measurement of ICP under intensive care unit conditions were included. Using a double lumen bolt, ptiO2 was measured simultaneously with Licox and Neurovent PTO. Ex vivo tests on both probes were conducted independently by the manufacturer of the Neurovent PTO (Raumedic AG, Germany)., Results: The average of individual mean ptiO2 measurements showed no relevant differences between the Licox (19.5+/-7.1) and Neurovent multiparameter probe (21.7+/-9.5). Twenty-eight Licox probes out of 30 showed proper functioning over the desired monitoring period. Raumedic multiparameter probes displayed a higher malfunction/handling error frequency (2 device errors, 11 handling errors). A comparison of the ptiO2 data between the Licox and Raumedic systems according to Bland and Altman was possible in 18 out of 30 patients and showed acceptable results (mean difference -1.24 mm Hg; limits of agreement: -25.1 to +22.6 mm Hg). A total of 95.2% of 96,083 recordings was within the calculated limits of agreement. Ex vivo tests of the probes after explantation revealed stable ICP and TBr function of the Raumedic probe. Precision of Zero ptiO2 did not differ between the probes, whereas precision of the 150 mm Hg ptiO2 was greater in the Raumedic probes., Conclusions: Combining 3 different neuromonitoring functions in 1 probe might ease monitoring by making a second (ptiO2) probe unnecessary. Interpretation of our data is limited by several factors: (1) monocentric study; (2) reduced mechanical probe stability, handling difficulties with the double lumen bolt; (3) design changes to improve mechanical stability will require further study; (4) conflict of interest with Raumedic because of its support for the study. The conclusion drawn from our study is that the new multiparameter probe evaluated does measure ICP, TBr, and ptiO2. But all the initial data given in this paper have to be interpreted cautiously. A new study will be necessary when the mechanical stability of the new probe has been improved.

Objective: A positive correlation between brain temperature and intracranial pressure (ICP) has been proposed for patients under intensive care conditions., Design and Methods: Data were recorded at 5-minute intervals in patients under ICP monitoring conditions. Brain temperature: combined ICP/temperature probe (Raumedic), core temperature: indwelling urinary catheter with temperature probe (Rüsch). The correlation between brain temperature and ICP was assessed by computing an estimated mean correlation coefficient (re) and by a time series analysis., Patients: Forty consecutive neurosurgical patients receiving intensive care therapy for trauma, cerebrovascular malformation, and spontaneous hemorrhage were studied. A total of 48,892 measurements (9778 h) were analyzed. No additional interventions were performed., Results: The median ICP was 14 mm Hg (range: -13 to 167). The brain temperature (median 38 degrees C; range 23.2 to 42.1) was 0.3 degrees C (range: -3.6 to 2.6) higher than the core temperature (median 37.7 degrees C; range 16.6 to 42.0), P<0.001. The mean Pearson correlation between ICP and brain temperature in all patients was re=0.13 (P<0.05); the time series analysis (assuming a possible lagged correlation between ICP and brain temperature) revealed a mean correlation of 0.05+/-0.25 (P<0.05). Both correlation coefficients indicate that any relationship between brain temperature and ICP accounts for less than 2% of the variability [coefficient of determination (r)<0.02]., Conclusions: These data do not support the notion of a clinically useful correlation between brain temperature and ICP.

When there is significant loss of spinal dura mater, dural substitution with synthetic or allogenic materials is essential. In the case of laminectomy, mechanical protection and reformation of the dorsal spinal canal may be useful. This is a report on a patient with total dura loss through tumour atrophy of the dura and laminae. In order to reconstruct the dorsal face of the spinal canal a polylactide sheet was cut and shaped to fit the physiological contour. A bovine dura substitute was firmly attached and sutured to the inner surface of the polylactide shield. The implant was wedged in between the pedicles and the facet joints and resulted in a water-tight dura substitute maintaining the shape of the spinal canal and protecting it against mechanical forces and intradural scar formation.

The paper reports on auto fluorescence phenomena of inter-vertebral human discs. It systematically investigates the auto fluorescence effects of ex vivo disc specimen and reports on surgical cases to demonstrate the potential value of the new method. The paper offers biologic explanations of the phenomenon and discusses the potential value of the UV auto fluorescence technique as a diagnostic tool. Intra- and postoperative observations are made by a surgical microscope with an integrated UV light source. Quantitative measurements were carried out using a photon counter and a spectrometer ex vivo. The auto fluorescence phenomenon allows the differentiation of traumatized and degenerated disc tissue intraoperatively in some cases, it allows the differentiation of bony and collagen endplate in cervical disc surgery. The source of the auto fluorescent light emission are amino acids of the collagen molecules. The proteoglycan components and the liquid components of the disc do not show relevant auto fluorescence. Emission wavelength of disc material is equivalent to color perception. It differs due to different collagen composition of the intervertebral disc components from yellow-green to blue-green and can be visualized in situ by naked eye.UV-auto fluorescence of inter-vertebral discs is a new clinical tool that has the potential to differentiate disc material from the anatomical surrounding, to distinguish between different fractions of the disc and to give information on the quality and status of the disc material. Since the technology has just emerged, it needs further investigations to quantify the clinical observations reported in this paper.

Objective: A negative effect of hyperglycemia on clinical outcome has been proposed for patients treated under intensive care conditions. So far, however, the safety and effect of fat based nutrition regimen, especially of olive oil based emulsions, have not been systematically studied., Design and Setting: Prospective, open-labeled, randomized, pilot study in a 14-bed surgical intensive care unit., Patients and Interventions: Thirty-three consecutive, severe multiple trauma patients (injury severity score 31.6+/-11.5) were included; 18 (L group) received a parenteral lipid-based nutrition; 15 (G group) were given a standard parenteral glucose-based nutrition., Measurements and Results: The energy expenditure (EE) showed no difference between groups and no significant difference between the energy intake/EE ratio. The daily mean energy intake was lower in the L group (17.9+/-6.3 kcal/kg) than in the G group (22.3+/-4.2 kcal/kg). Triglycerides and nitrogen balance showed no significant differences between groups. The L group had significantly lower blood glucose (L 7.4+/-1.6, G 8.7+/-1.6 mmol/l), carbon dioxide production, and minute volume and shorter duration of mechanical ventilation (L 13.0+/-8.9, G 20.4+/-7.0 days), and stay in the ICU (L 17.9+/-11.2, G 25.1+/-7.0 days)., Conclusions: Our findings suggest a good tolerance, a decrease in blood glucose, clinically relevant shortening of ICU stay, and shorter time on mechanical ventilation for patients treated with olive oil based than with conventional glucose-heavy nutrition.

Background: Recent developments in sensor-servomotor-driven microscopes again initiated a discussion on the value of such technology for practical use in neurosurgery. The need for less force in moving a motor-supported microscope is advantageous. However, questions remain if well-known difficulties in the past such as resonance phenomenon, loss of natural feeling, and unequal handling forces in different situations have been overcome by the new generation of sensor-servo-supported surgical microscopes., Methods: Handling forces of a mechanically counterbalanced neurosurgical microscope (Zeiss NC4, Zeiss, Oberkochen, Germany) were compared with those of a sensor-servo-supported neurosurgical microscope (Moeller HiR 20-1000, Moeller, Wedel, Germany). Handling forces were correlated with the surface electromyogram measurement of the muscle activity of 4 neurosurgeons. The activity of the forearm muscles was measured while handling the 2 different microscopes in standardized tests., Results: The electrophysiologic measurement revealed that significantly less muscle activity was required to handle the sensor-servo-driven microscope in all directions. The untrained surgeons profited less than the skilled ones. Differences were most evident with disbalanced microscopes., Conclusions: With this technology, the neurosurgeons exerted less effort, especially in strenuous test situations where the single-handed use of the microscope was mandatory. The reduced muscle forces that move the sensor-servo-type microscope and the continuously balanced state that might help prevent unwanted correction movements will ease intraoperative handling in general.

Summary: Venous aneurysms so-called isolated cerebral varix, are known as a related pathology in arteriovenous malformations (AVM) due to the arterial pressure on venous drainage (16). They are also observed in combination with developmental venous anomalies (DVA) (2,4,8,15). However, isolated varix is a rare entity (1,7,11,13). They appear in most cases without neurological deficits. Some of the cases mimic a meningioma due to their manifestation in CT and MR imaging and their axial cortical localization. The case presented here is a isolated varix of a cortical vein located rostral to the motor strip. The patient was operated on successfully. The MRI and the histology of the case are presented.

Background: The 60 year old women with no prior history of arrhythmia or other cardiac symptoms was operated on for a cervical disc herniation at the level C7/D1. The C8 nerve root was visualized via a posterior approach., Findings: Removal of the sequestrum and irritation of the anterior root with surgical instruments triggered cardiac arrest., Interpretation: We offer the opinion that irritation of the anterior root led to diminished activity of the supraspinal sympathetic control system and consecutive hyper-activation of the parasympathetic system.

Intraoperative neurophysiological mapping and monitoring of eloquent brain areas can be combined with image-guided localisation to enhance the safety and efficacy of surgical procedures in the motor cortex. We designed a new type of cortical electrode which can be repeatedly placed on the cortical surface and allows accurate and reproducible stimulation by means of a navigation pointer. The newly designed device consists of a monopolar electrode contact for direct cortical stimulation, housed in a holder which allows placement, easy removal, and precise repeated placement of a surgical navigation pointer. It can be used for navigation-guided, high-frequency anodal monopolar cortical stimulation (MCS) for the mapping of eloquent cortex, and for monitoring of motor pathways. While the cortex is stimulated, compound muscle action potentials (CMAP) are recorded from muscles of the contralateral extremities and are assessed both qualitatively and quantitatively. When the device is used in combination with intraoperative navigation, the stimulation sites may optionally be registered or displayed on the system monitor. This allows repeated pinpointing and obviates the need for strip or grid electrodes in the operative field; although such electrodes may be useful for continuous monitoring, they often are in the surgeon's way. In addition, the primary and supplementary motor cortex can be mapped by determining the location of the sites of stimulation on surface-projected images of the cerebral cortex.

Summary: This report describes three years of clinical experience with a new set of devices aimed at improving functional MRI of speech areas. They provide a valuable tool for pre-operative definition of hemispheric localization and spatial extension of these areas, especially in left-handed persons. The fibre-optic device described here transmits stimuli for cognitive tasks to patients undergoing MR investigations. Cognitive tasks elicit a defined brain activity lasting for several minutes. The resultant metabolic changes are detectable by functional MRI. The software (FIT ware) applied to process raw data allows semi-automated segmentation of the brain so as to obtain 3D images. Furthermore it allows the superposition of functional data. The effectiveness of the equipment was assessed on the basis of data from 140 fMRI studies. Intra-operative verification in eight patients with tumours located in the speech areas showed that the new set-up identified the speech-dominant side in each case and located speech areas in accordance with electrophysiological procedures.

Intra-operative neurophysiological techniques allow reliable identification of the sensorimotor region and make their anatomical and functional preservation feasible. Monopolar cortical stimulation has recently been described as a new mapping technique. In the present study this method was compared to the "traditional" technique of bipolar stimulation. Functional mapping of the motor cortex was performed in 35 patients during surgery in the central region. The central sulcus (CS) was identified by somatosensory evoked potential (SEP) phase reversal. Cortical motor mapping was first performed by monopolar anodal stimulation with a train of 500 Hz (7-10 pulses) followed by bipolar stimulation (pulses at 60 Hz with max. 4 sec train duration). Surgery was performed under general anaesthesia without muscle relaxants. Of 280 motor responses elicited by bipolar cortical stimulation, 54.23% [152] were located in the primary motor cortex (PMC), 37.85% 106[ outside the motor strip in the secondary motor cortex (SMC), and 8% 22[ posterior to the CS. Of 175 motor responses elicited by monopolar cortical stimulation. 68.57% 120[ were located in the SMC, 23.42% 41[ in the SMC and 8% 14[ posterior to the CS. Contrary to the general clinical view, there is considerable overlapping of primary motor units over a cortical area much broader than the "classical" narrow motor strip along the CS. Bipolar cortical stimulation is more sensitive than monopolar for mapping motor function in the premotor frontal cortex. Both methods are equally sensitive for mapping the primary motor cortex.

This study reports the development of a highly sensitive and reproducible RIA for the measurement of 3,5-diiodothyronine (3,5-T2) in human serum and tissue. The RIA employs 3-bromo-5-[125I]iodo-L-thyronine (3-Br-5-[125I]T1) as tracer, which was synthesized carrier free by an interhalogen exchange from 3,5-dibromo-L-thyronine (3,5-Br2T0). The detection limits were 1.0 fmol/g and 0.8 pmol/L in human brain tissue and serum, respectively. T3, diiodothyroacetic acid, and 3-monoiodothyronine cross-reacted with a 3,5-T2 antibody to the extent of 0.06%, 0.13%, and 0.65%, respectively. Serum concentrations of 3,5-T2 were measured in 62 healthy controls and 4 groups of patients with nonthyroidal illness, i.e. patients with sepsis (n = 24), liver diseases (n = 23), head and/or brain injury n = 15), and brain tumors (n = 21). The mean serum level of 3,5-T2 in the healthy subjects was 16.2 +/- 6.4 pmol/L. Concentrations of 3,5-T2 were significantly elevated in patients with sepsis (46.7 +/- 48.8 pmol/L; P < 0.01), liver diseases (24.8 +/- 14.9 pmol/L; P < 0.01), head and/or brain injury (24.1 +/- 11.3 pmol/L; P < 0.05), and brain tumors (21.6 +/- 4.8 pmol/L; P < 0.01). In all 4 patient groups, serum levels of T3 were significantly reduced, confirming the existence of a low T3 syndrome in these diseases. Serum concentrations of 3,5-T2 were significantly elevated in patients with hyperthyroidism (n = 9) and were reduced in patients with hypothyroidism (n = 8). The levels of T4, T3, and 3,5-T2 were measured in normal human tissue samples from the pituitary gland and various brain regions and in brain tumors. In normal brain tissue, the concentrations of 3,5-T2 ranged between 70-150 fmol/g, and the ratio of T3 to 3,5-T2 was approximately 20:1. In brain tumors, however, T3 levels were markedly lower, resulting in a ratio of T3 to 3,5-T2 of approximately 1:1. Recent findings suggest a physiological, thyromimetic role of 3,5-T2, possibly stimulating mitochondrial respiratory chain activity. Should this prove to be correct, then the increased availability of 3,5-T2 in nonthyroidal illness may be one factor involved in maintaining clinical euthyroidism in patients with reduced serum levels of T3 during nonthyroidal illness.

In the present study we investigated the biochemical properties of in vitro phenolic (5'D) and tyrosyl (5D) ring deiodination and the tissue concentrations of T4, T3, and rT3 in adult human central nervous system (CNS) tissue. All samples were obtained from nontumoral tissue at autopsy (n = 6) or neurosurgical operation (n = 5). Both phenolic and tyrosyl ring deiodinase activities were demonstrable in all samples obtained intraoperatively, whereas only tyrosyl ring deiodination was evident in the tissues obtained postmortem. The phenolic ring deiodination pathway corresponded to the type II 5'-deiodinase isoenzyme with regard to its high affinity for T4 and rT3 (Km = 2.2 and 2.4 nmol/L, respectively), its insensitivity to 6-propyl-n-2-thiouracil (PTU), and the sequential reaction mechanism. No PTU-sensitive 5'-deiodination of rT3 was demonstrable. Tyrosyl ring deiodination of both T4 and T3 showed typical type III 5D kinetics (Ka, 6.5 nmol/L for T4 and 3.4 nmol/L for T3) and was PTU insensitive. Nanomolar concentrations of tissue T4, T3, and rT3 were detected in samples obtained both intraoperatively and postmortem. They were very similar to the absolute values of the apparent Km for T4, T3, and rT3 in the phenolic and tyrosyl ring deiodination pathways. In conclusion, we have demonstrated the coexistence of both phenolic and tyrosyl ring deiodinase activities in the human CNS. Their kinetic characteristics, substrate specificity, and reaction mechanisms are very similar to the corresponding type II 5'- and type III 5-iodothyronine deiodinase activities in rat brain. In contrast to the findings in the rat CNS, no PTU-sensitive phenolic ring deiodinase (i.e. type I 5'D) activity was found in the human CNS. This may explain the relatively high tissue concentrations of rT3.

Medical examinations only insufficiently measure cognitive impairment in neurological and neurosurgical patients. Due to costs an personnel shortages, adequate neuropsychological test methods are typically bypassed. Indeed, the very size and methodological problems of current tests impede their application in clinical practice. To resolve this dissatisfying state of affairs, we have developed a standardized, scored form of initial neuropsychological examination. The Neuropsychological Screening Test (NST) comprises 45 items, is easy to handle, and can be conducted in 15-20 min. The NST measures psychic performance along functional parameters such as orientation in place and time, primary and secondary language, visuospatial ability, attention, and memory skills. We have assessed the validity and reliability of the NST in a prospective study. 129 neurosurgical patients (60% malignant or benign cerebral tumors, 21% vascular malformations with and without subarachnoid hemorrhage, 6% traumatic brain injury, 3% hydrocephalus, 10% others) and 52 control subjects were included in the study. The difference in average total NST-scores was highly significant for the two groups (t = -7.84, DF = 177.93, p < .001). In addition, two chronologically separate subsamples of NCH patients (N = 81) and controls (N = 35) were tested using the Mini-Mental State (MMS). The correlation between total NST-score and MMS results was r = .49 (p < .001). Cross-tabulation was used to set a cut-off score, by means of which 80% of the neurosurgical patients were identified as true positive and 74% of the controls as true negative. A 24-hour retest confirmed the NST as reliable to .85 (p < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Although the loss of tumor suppressor genes and the activation of oncogenes have been established as two of the fundamental mechanisms of tumorigenesis in human cancer, little is known about the possible interactions between these two mechanisms. Loss of genetic material on chromosome 10 and amplification of the epidermal growth factor receptor (EGFR) gene are the most frequently reported genetic abnormalities in glioblastoma multiforme. In order to examine a possible correlation between these two genetic aberrations, the authors studied 106 gliomas (58 glioblastomas, 14 anaplastic astrocytomas, five astrocytomas, nine pilocytic astrocytomas, seven mixed gliomas, six oligodendrogliomas, two ependymomas, one subependymoma, one subependymal giant-cell astrocytoma, and three gangliogliomas) with Southern blot analysis for loss of heterozygosity on both arms of chromosome 10 and for amplification of the EGFR gene. Both the loss of genetic material on chromosome 10 and EGFR gene amplification were restricted to the glioblastomas. Of the 58 glioblastoma patients, 72% showed loss of chromosome 10 and 38% showed EGFR gene amplification. The remaining 28% had neither loss of chromosome 10 nor EGFR gene amplification. Without exception, the glioblastomas that exhibited EGFR gene amplification had also lost genetic material on chromosome 10 (p less than 0.001). This invariable association suggests a relationship between the two genetic events. Moreover, the presence of 15 cases of glioblastoma with loss of chromosome 10 but without EGFR gene amplification may further imply that the loss of a tumor suppressor gene (or genes) on chromosome 10 precedes EGFR gene amplification in glioblastoma tumorigenesis.