An attempt to use Gore-Tex surgical membrane in lumbar disc surgery

BACKGROUND: Peridural fibrosis developing after lumbar discectomy may be responsible for as much as 20% of all Failed Back Surgery Syndrome. A variety of biological and non-biological materials have been used as a barrier to invasion of fibrous tissue into the vertebral canal. AIM: The purpose of this study was to evaluate the use of expanded polytetrafluoroethylene (ePTFE) surgical membrane (Gore-Tex membrane) to inhibit peridural fibrosis and reduce FBSS symptoms after lumbar discectomy. MATERIAL AND METHODS: In a prospective study we compared postoperative results in 20 patients who had an ePTFE membrane implanted during lumbar discectomy with the results in 20 patients in whom no material was implanted. The outcomes were evaluated using a questionnaire on activities of daily living according to the Low Back Outcome Score, pain grading scale -- Visual Analog Scale, assessment of Lasegue sign and MRI 18-24 months after the operation for all patients. RESULTS: The authors found no evident positive clinical and radiological effects of using ePTFE surgical membrane during lumbar discectomy. CONCLUSIONS: 1. It is impossible to prove that ePTFE membrane used during lumbar discectomy essentially prevents postoperative peridural scar formation. 2. The use of ePTFE membrane does not improve the outcome of the surgical treatment of lumbar disc herniation.     

Spontaneous spinal cord herniation: a rare cause of the Brown-Sequard syndrome

Recent reports have shown that spontaneous spinal cord herniation in the thoracic segment of the spine may be one of the causes of the progressive spinal cord lesion. Although it was described for the first time by Wortzman in 1974, it was only in early 1990s that a growing number of publications on single cases of the condition started to be observed. In the relevant literature collected by us we found reports on 53 patients altogether. In a number of cases herniation was diagnosed only intraoperatively in spite of complex radiological diagnostics. The analysis of relevant literature shows that spontaneous or idiopathic spinal cord herniation has a very typical clinical picture and most cases share a number of features, such as the clinical condition, age and sex of the patient as well as the level and location of the entity and its radiological picture. We conclude that spontaneous herniation of the spinal cord may be not as rare as previously thought and that it should be always taken into account in differential diagnostics of progressive myelopathy in the thoracic segment in middle-aged patients, especially females.     

Change in otosclerosis presentation over two decades

Presentation of otosclerosis in eighties and nineties was compared on the basis of analysis of patients' documentation. A group I of 80 patients treated in 1980-1990 and a group II of 148 patients treated in 1991-2000 were compared with regard to sex, age, incidence of oval window obliteration and bilateral disease. Bone conduction and air conduction threshold and air-bone gap were also compared. There was no difference between two groups regarding sex, age and bone conduction threshold. Oval window obliteration was found in 8 (10%) patients of group I and in 7 (4.7%) patients of group II and the difference was not significant. Bilateral otosclerosis was diagnosed in 77 (96.3%) patients of group I and in 121 (81.8%) patients of group II and the difference was significant (p < 0.01). Air conduction threshold and air-bone gap in patients treated in nineties were significantly smaller than in eighties (p < 0.001). In the last decade patients with otosclerosis presented with smaller hearing loss, smaller air-bone gap and had bilateral disease less frequently than patients in eighties.     

Surface functionalization and grafting of heparin and/or RGD by an aqueous-based process to a poly(carbonate-urea)urethane cardiovascular graft for cellular engineering applications

An aqueous-based process is reported for surface functionalization and grafting of anticoagulant and cell attachment moieties, such as heparin and/or arginine-glycine- aspartate (RGD) onto the lumenal surface of a prefabricated cardiovascular graft (5 mm i.d.) made of poly(carbonate- urea)urethane (MyoLink). It is a three-stage process, all aqueous: (1) hydroxylation using an azobis compound, particularly 2,2'-azobis(2-methylpropionamidine)dihydrochloride, which abstracts hydrogen via an electron transfer process from the polyurethane surface (strong oxygen purging); (2) grafting using the as-generated hydroxide groups to allow attachment of an acrylamide monomer using a conventional ceric ion technique (strong nitrogen purging); and (3) moiety attachment, preactivated with [1-ethyl-3-(3-dimethylaminopropyl)carbodiimide] in acidic solution. The technique was validated by attaching heparin and RGD/heparin to the MyoLink polymer. Following bonding, the graft segments were exposed to prolonged physiologic shear force in a flow circuit (10 h). The grafts first were analyzed by X-ray photoelectron spectroscopy (XPS) to determine the degree of attachment of the moieties and then by materials methods to assess whether any degradation of the graft material itself had occurred since polyurethanes with carbonate amorphous segments are readily susceptible to hydrolytic degradation following functionalization processes. XPS showed the moieties were present on the surface at a concentration of 10%. The S2p(3/2) states of sulfur indicated that there were high degrees of ionic covalent bonding, indicating high degrees of moiety bioactivity. Heparin was found to be present from the sulfur signal, namely NSO(3). RGD was found to be present from the nitrogen signal present at the binding energy of 399 eV. Macroscopic analysis and ESEM showed no signs of polyurethane degradation or small protuberances indicative of microgel formation. Quality control (QC) showed that the internal diameters and wall thicknesses of all the respective grafts postbonding remained within normal batch release limits (5 +/- 0.1mm, i.d.; 0.9 +/- 0.05 mm, wall thickness). Gel permeation chromatography (GPC) showed there were no statistical differences between the control, which was nonbonded (MN 45,300, MW 98,500, D 2.17) and all of the bonded samples, respectively (MN 41,800, MW 104,000, D 2.45). Radial tensile strength (RTS) analysis also showed that all of the respective samples postbonding (1.48N/mm) remained within batch release specifications (>1N/mm). A simple aqueous polymer surface functionalization and grafting technique has been developed for covalent bonding of anticoagulant and cell-attachment moieties onto poly(carbonate-urea)urethane(s) and has been validated by surface and materials analyses. The moieties were attached uniformly and were bioactive at a high surface density. No degradation in terms of a loss in mechanical properties was evident following bonding of the polyurethane.     

Differential diagnosis of frontal syndrome in patients with closed-head injuries

Background. A common sequela of head injury is "frontal syndrome", consisting in characteristic neurobehavioral disturbances. However, there is no ecologically valid research tool that would clearly indicate the presence of this syndrome. The goal of this article is to evaluate the authorized the Polish version of the Frontal Behavioral Inventory (FBInv), used to differentiate fronto-temporal dementia (FTD) from other dementias. Material and methods. The research involved 95 patients treated at the centers represented by the authors, divided into 3 groups: CHI, consisting of 39 patients with traumatic frontal lobe injuries; FTD, consisting of 28 patients with fronto-temporal dementia; and a control group of persons with post-traumatic depression without injury to the frontal lobes. The results were based on data obtained from caregivers in 24 categories of patient behavior covered by the FBInv. Results. We found important differences in total scores between patients with frontal syndrome from groups CHI and FTD, as against patients with post-traumatic depression. There are also noticeable differences between patients in group FTD and group CHI in terms of scores on particular test items. Conclusions. The FBInv in the authorized Polish version is both sensitive and specific in measuring neurobehavioral disturbances occurring in patients with post-traumatic damage to the changes in the behavioral and personality of these patients with the passage of time since injury or onset should be the topic of further research.     

Myxopapillary ependymoma of the lateral ventricle with local recurrences: histopathological and ultrastructural analysis of a case

An exceptional case of a recurrent intracranial ependymoma of myxopapillary type arising from the lateral ventricle is reported in a 37-year-old man. This distinctive morphological variant of ependymoma is virtually restricted to the region of cauda equina and filum terminale or occasionally to pre- or post-sacral soft tissue. The intracranial cases of myxopapillary ependymoma are extremely rare and are generally associated with the primary ependymal tumour at the typical lumbosacral site. This case of intraventricular myxopapillary ependymoma did not demonstrate any MRI evidence of a primary spinal cord tumour. Moreover, the initial diagnosis of this histologically benign tumour was followed by two tumour recurrences during the three-year follow-up period. To our knowledge, this is the third documented case of a primary intraventricular myxopapillary ependymoma and the first one of intracranial localisation associated with local recurrences.     

Molecular mechanisms of glutamate neurotoxicity in mixed cultures of NT2-derived neurons and astrocytes: protective effects of coenzyme Q10

Although glutamate excitotoxicity has long been implicated in neuronal cell death associated with a variety of neurological disorders, the molecular mechanisms underlying this process are not yet fully understood. In part, this is due to the lack of relevant experimental cell systems recapitulating the in vivo neuronal environment, mainly neuronal-glial interactions. To explore these mechanisms, we have analyzed the cytotoxic effects of glutamate on mixed cultures of NT2/N neurons and NT2/A astrocytes derived from human NT2/D1 cells. In these cultures, the neurons were resistant to glutamate alone (up to 2 mM for 24-48 hr), but they responded to a simultaneous exposure to 0.5 mM glutamate and 6 hr of hypoxia. Neuronal cell death occurred during subsequent periods of reoxygenation (>30% within 24 hr). This was associated with a marked decrease of intracellular ATP, a significant increase in reactive oxygen species (ROS) and downregulation of glutamate uptake by astrocytes. Thus, under energy failure and high levels of ROS production, only the neurons from these mixed cultures succumbed to glutamate neurotoxicity; the astrocytic cells remained unaffected by the treatment. Taken together, our data suggested that glutamate excitotoxicity might be due to the energy failure and oxidative stress affecting the properties of the NMDA glutamate receptors and causing impairment of glutamate transporters. Cells pretreated for 72 hr with 10 microg/ml of coenzyme Q(10) (functions both as a ROS scavenger and co-factor of mitochondrial electron transport), were protected, suggesting a useful role for coenzyme Q(10) in treatments of neurological diseases associated with glutamate excitotoxicity. A model of the complex interactions between neurons and astrocytes in regulating glutamate metabolism is presented.     

Neuroprotective effects of coenzyme Q10 at rostral ventrolateral medulla against fatality during experimental endotoxemia in the rat

Coenzyme Q10 (CoQ10, ubiquinone) is a highly mobile electron carrier in the mitochondrial respiratory chain that also acts as an antioxidant. We evaluated the neuroprotective efficacy of CoQ10 against fatality in an experimental model of endotoxemia that mimics systemic inflammatory response syndrome using a novel water-soluble formulation of this quinone derivative. Experiments were conducted in adult male Sprague-Dawley rats that were maintained under propofol anesthesia. Intravenous administration of Escherichia coli lipopolysaccharide (LPS; 30 mg/kg) induced progressive hypotension, with death ensuing within 4 h. The sequence of cardiovascular events during this LPS-induced endotoxemia can be divided into a reduction (Phase I), followed by an augmentation (Phase II; "pro-life" phase) and a secondary decrease (Phase III; "pro-death" phase) in the power density of the vasomotor components (0-0.8 Hz) of systemic arterial pressure signals. Pretreatment by microinjection bilaterally of CoQ10 (1 or 2 microg) into the rostral ventrolateral medulla (RVLM), the medullary origin of sympathetic vasomotor tone, significantly diminished mortality, prolonged survival time, and reduced the slope or magnitude of the LPS-induced hypotension. CoQ10 pretreatment also significantly prolonged the duration of and augmented the total power density of the vasomotor components of systemic arterial pressure signals in Phase II endotoxemia. The increase in superoxide anion production induced by LPS at the RVLM during Phases II and III endotoxemia was also significantly blunted. We conclude that CoQ10 provides neuroprotection against fatality during experimental endotoxemia by reducing superoxide anion production at the RVLM, whose neuronal activity is intimately related to the "life-and-death" process.     

Endothelial Dysfunction in Patients with Noncomplicated and Complicated Hypertension

Endothelial dysfunction plays an important role in the pathogenesis of hypertension. Other risk factors of atherosclerosis also affect its development. The aim of the study was to assess nitric oxide metabolites concentration (nitrites and nitrates No_x) and endothelin (ET-1) in plasma and cyclic 3,5-guanosine monophosphate (cGMP) in 24 h-urine collection in patients with noncomplicated hypertension without risk factors of atherosclerosis and in hypertensive patients with coronary artery disease (CAD). Sixty-eight subjects were included in the study (44 men, 24 women), aged 47 ± 76 years, allotted into four groups: I – controls (18 clinically healthy subjects); II – 12 subjects with hypertension without risk factors of atherosclerosis; III – 16 subjects with hypertension and risk factors of atherosclerosis; and IV – 22 subjects with hypertension and CAD. Plasma NO_x concentration was determined using the Greiss method, plasma ET-1 by ELISA, and urine cGMP using the immunoenzymatic method. Plasma NO_x concentration was 14.00 ± 6.88 μmol/L in group I, in group II – 18.62 ± 5.84 μmol, in group III – 9.96 ± 4.72 μmol/L, and in group IV – 8.78 ± 3.72 μmol/L. Statistically significant differences were between groups I and III (p < 0.05) and I and IV (p < 0.04) and groups II and III (p < 0.01) and II and IV (p < 0.01). The concentration of cGMP in 24 h urine collection was in group I – 40 ± 24 pmol/L; in group II – 54 ± 41 pmol/L; in group III – 38 ± 32 pmol/L; and in group IV – 42 ± 36 pmol/L. There were no significant differences between the groups. Plasma ET-1 concentration was 3.86 ± 0.52 pg/mL in group I, in group II – 4.05 ± 0.71 pg/mL, in group III – 4.22 ± 0.79 pg/mL and in group IV – 4.38 ± 0.75 pg/mL. Statistically significant differences were between group I and III (p < 0.05), I and IV (p < 0.03), and between group II and IV (p < 0.04). Endothelial dysfunction was not found in hypertensive patients without a family history of cardiovascular diseases and without other risk factors of atherosclerosis. Deterioration of endothelial function was observed in patients with hypertension with risk factors of atherosclerosis. It was most pronounced in those with CAD.