Current possibilities of dural reconstruction in neurosurgery.

An integral part of intracranial neurosurgery is the opening of the subdural space and its subsequent closure or reconstruction after the surgery. The optimal goal is a primary watertight suture, although that is often unfeasible for various reasons. Cerebrospinal fluid leakage in postoperative care is an undesirable and potentially dangerous complication of most of the surgical interventions. The aim of this article is to present the current possibilities of dural reconstruction in neurosurgery. Key words:  mater cerebrospinal fluid leakage dural defect craniectomy.

Comparing endoscopic and open decompression of the ulnar nerve in cubital tunnel syndrome: a prospective randomized study.

BACKGROUND: Prospective randomized data is currently lacking which compares endoscopically assisted surgery with open surgical techniques in the treatment of cubital tunnel syndrome (CUTS). The aim of this study is to compare patient outcome in both techniques. METHOD: This prospective study comprised of 45 patients who, between October 2014 and February 2017, were randomly assigned to undergo either endoscopic or open surgery (22 and 23 patients respectively) for decompression of the ulnar nerve. Patients were followed up at 3 and 12 months postoperation. McGowan classification was used to determine the severity of symptoms. Surgical outcome was evaluated by Bishop classification. Pain levels were monitored according to gender from 0 to 10 days postoperation. Other factors investigated were chronic scar pain, working status, operation duration, and patient satisfaction regarding postoperative scarring and the procedure itself. RESULTS: Both methods are equally effective in the treatment of CUTS (Bishop score excellent or good 90% vs 96%). Postoperative pain is significant particularly in the first few days following surgery, but with no significant difference depending on procedure. In the open group, postoperative pain was significantly higher in women than in men; pain did not differ between the sexes in the endoscopic group. The tendency to lower levels of pain among endoscopically operated women in comparison with women in the open group was not statistically notable. Patients who underwent open decompression experienced notably higher levels of postoperative chronic scar pain. Although working status and satisfaction with the surgical outcome were the same in both groups, satisfaction with scarring was higher in the endoscopy group. Operation time was significantly longer by endoscopy. CONCLUSIONS: Both studied methods produced equal satisfactory outcomes in the treatment of CUTS. Endoscopy has the potential to minimize chronic scar pain and improve scarring esthetics, at the expense of longer operating time. CLINICAL TRIAL REGISTRATION NUMBER: Supported by Ministry of Health, Czech Republic-conceptual development of research organization (FNOs/2014, project number 20). Graphical abstract Median postoperative pain from 0 to 10 days by group.

Impact of acute and subchronic inhalation exposure to PbO nanoparticles on mice.

Lead nanoparticles (NPs) are released into air from metal processing, road transport or combustion processes. Inhalation exposure is therefore very likely to occur. However, even though the effects of bulk lead are well known, there is limited knowledge regarding impact of Pb NPs inhalation. This study focused on acute and subchronic exposures to lead oxide nanoparticles (PbO NPs). Mice were exposed to PbO NPs in whole body inhalation chambers for 4-72 h in acute experiment (4.05 × 106 PbO NPs/cm3), and for 1-11 weeks in subchronic experiment (3.83 × 105 particles/cm3 in lower and 1.93 × 106 particles/cm3 in higher exposure group). Presence of NPs was confirmed in all studied organs, including brain, which is very important considering lead neurotoxicity. Lead concentration gradually increased in all tissues depending on the exposure concentration and duration. The most burdened organs were lung and kidney, however liver and brain also showed significant increase of lead concentration during exposure. Histological analysis documented numerous morphological alterations and tissue damage, mainly in lung, but also in liver. Mild pathological changes were observed also in kidney and brain. Levels of glutathione (reduced and oxidized) were modulated mainly in lung in both, acute and subchronic exposures. Increase of lipid peroxidation was observed in kidney after acute exposure. This study characterized impacts of short to longer-term inhalation exposure, proved transport of PbO NPs to secondary organs, documented time and concentration dependent gradual increase of Pb concentration and histopathological damage in tissues.

Sub-chronic inhalation of lead oxide nanoparticles revealed their broad distribution and tissue-specific subcellular localization in target organs.

BACKGROUND: Lead is well known environmental pollutant, which can cause toxic effects in multiple organ systems. However, the influence of lead oxide nanoparticles, frequently emitted to the environment by high temperature technological processes, is still concealed. Therefore, we investigate lead oxide nanoparticle distribution through the body upon their entry into lungs and determine the microscopic and ultramicroscopic changes caused by the nanoparticles in primary and secondary target organs. METHODS: Adult female mice (ICR strain) were continuously exposed to lead oxide nanoparticles (PbO-NPs) with an average concentration approximately 106 particles/cm3 for 6 weeks (24 h/day, 7 days/week). At the end of the exposure period, lung, brain, liver, kidney, spleen, and blood were collected for chemical, histological, immunohistochemical and electron microscopic analyses. RESULTS: Lead content was found to be the highest in the kidney and lungs, followed by the liver and spleen; the smallest content of lead was found in brain. Nanoparticles were located in all analysed tissues and their highest number was found in the lung and liver. Kidney, spleen and brain contained lower number of nanoparticles, being about the same in all three organs. Lungs of animals exposed to lead oxide nanoparticles exhibited hyperaemia, small areas of atelectasis, alveolar emphysema, focal acute catarrhal bronchiolitis and also haemostasis with presence of siderophages in some animals. Nanoparticles were located in phagosomes or formed clusters within cytoplasmic vesicles. In the liver, lead oxide nanoparticle exposure caused hepatic remodeling with enlargement and hydropic degeneration of hepatocytes, centrilobular hypertrophy of hepatocytes with karyomegaly, areas of hepatic necrosis, occasional periportal inflammation, and extensive accumulation of lipid droplets. Nanoparticles were accumulated within mitochondria and peroxisomes forming aggregates enveloped by an electron-dense mitochondrial matrix. Only in some kidney samples, we observed areas of inflammatory infiltrates around renal corpuscles, tubules or vessels in the cortex. Lead oxide nanoparticles were dispersed in the cytoplasm, but not within cell organelles. There were no significant morphological changes in the spleen as a secondary target organ. Thus, pathological changes correlated with the amount of nanoparticles found in cells rather than with the concentration of lead in a given organ. CONCLUSIONS: Sub-chronic exposure to lead oxide nanoparticles has profound negative effects at both cellular and tissue levels. Notably, the fate and arrangement of lead oxide nanoparticles were dependent on the type of organs.

Impact of acute and chronic inhalation exposure to CdO nanoparticles on mice.

Cadmium nanoparticles can represent a risk in both industrial and environmental settings, but there is little knowledge on the impacts of their inhalation, especially concerning longer-term exposures. In this study, mice were exposed to cadmium oxide (CdO) nanoparticles in whole body inhalation chambers for 4 to 72 h in acute and 1 to 13 weeks (24 h/day, 7 days/week) in chronic exposure to investigate the dynamics of nanoparticle uptake and effects. In the acute experiment, mice were exposed to 2.95 × 106 particles/cm3 (31.7 µg CdO/m3). The same concentration and a lower one (1.18 × 106 particles/cm3, 12.7 µg CdO/m3) were used for the chronic exposure. Transmission electron microscopy documented distribution of nanoparticles into all studied organs. Major portion of nanoparticles was retained in the lung, but longer exposure led to a greater relative redistribution into secondary organs, namely the kidney, and also the liver and spleen. Accumulation of Cd in the lung and liver occurred already after 24 h and in the brain, kidney, and spleen after 72 h of exposure, and a further increase of Cd levels was observed throughout the chronic exposure. There were significant differences in both Cd accumulation and effects between the two exposure doses. Lung weight in the higher exposure group increased up to 2-fold compared to the control. Histological analyses showed dose-dependent alterations in lung and liver morphology and damage to their tissue. Modulation of oxidative stress parameters including glutathione levels and increased lipid peroxidation occurred mainly after the greater chronic exposure. The results emphasize risk of longer-term inhalation of cadmium nanoparticles, since adverse effects occurring after shorter exposures gradually progressed with a longer exposure duration.

Simultaneous determination of reduced and oxidized glutathione in tissues by a novel liquid chromatography-mass spectrometry method: application in an inhalation study of Cd nanoparticles.

The paper presents the development of an advanced extraction and fast analytical LC MS/MS method for simultaneous analyses of reduced and oxidized glutathione (GSH and GSSG, respectively) in different animal tissues. The simultaneous determination of GSH and GSSG is crucial because the amount and ratio of both GSH and GSSG may be altered in response to oxidative stress, an important mechanism of toxicity. The method uses the derivatization of free thiol groups in GSH. Its performance was demonstrated for less explored tissues (lung, brain, and liver) in mouse. The combined extraction and analytical method has very low variability and good reproducibility, maximum coefficients of variance for within-run and between-run analyses under 8 %, and low limits of quantification; for GSH and GSSG, these were 0.2 nM (0.06 ng/mL) and 10 nM (6 ng/mL), respectively. The performance of the method was further demonstrated in a model experiment addressing changes in GSH and GSSG concentrations in lung of mice exposed to CdO nanoparticles during acute 72 h and chronic 13-week exposures. Inhalation exposure led to increased GSH concentrations in lung. GSSG levels were in general not affected; nonsignificant suppression occurred only after the longer 13-week period of exposure. The developed method for the sensitive detection of both GSH and GSSG in very low tissue mass enables these parameters to be studied in cases where only a little sample is available, i.e. in small organisms or in small amounts of tissue.

Wet effluent diffusion denuder technique and determination of volatile organic compounds in air. I. Oxo compounds (alcohols and ketones).

The wet effluent diffusion denuder (WEDD) preconcentration technique for the determination of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-pentanol, acetone, methyl ethyl ketone, diethyl ketone and methyl n-propyl ketone in air is discussed. The compounds are continuously collected into a thin film of deionized water flowing down the inner wall of the cylindrical wet effluent diffusion denuder. The concentrate is analysed by gas chromatography. Detection limits of alcohols and ketones are as low as 1 microg/l (GC-flame ionization detection) and/or 1 ng/l (GC-MS). This technique could be applicable for the continuous monitoring of ppb (v/v) levels of both alcohols and ketones in the air.

Pressurised liquid extraction of ketones of polycyclic aromatic hydrocarbons from soil.

Pressurised liquid extraction (PLE) was used in the extraction of three ketones of polycyclic aromatic hydrocarbons from the sample of a soil highly contaminated with polycyclic polyaromatic compounds. The choice of solvent was the only factor that considerably influenced the extraction efficiency of PLE under the conditions recommended in Method 3545A promulgated by the United States Environmental Protection Agency. The dichloromethane-ethanol solvent mixture was found to be the most efficient solvent. PLE using this mixture provided better recoveries of all analysed ketones relative to Soxhlet extraction.

[Liquid ventilation. 2]. / Kapalinová ventilace--2. cást.

The authors made two series of experiments in rabbits, using liquid ventilation. The first group was ventilated manually using RM 101 solution with an equilibration period of 30 and 60 sec., Tv = 10 ml/kg after previous administration of 30 ml/kg RM 101 at the beginning. The second group was ventilated using a specially developed liquid ventilator--part of the animals was ventilated with an equilibration interval of 30-90 sec., Tv = 10 ml/kg with administration of an initial dose od 30 ml/kg of RM 101 solution, a part of the animals in a continual manner, i.e. without an equilibration period and without administration of the initial dose of the solution. From the results it is apparent that the optimal way as regards blood gases and minimal manner of liquid ventilation. When this method was used during the 180 minutes of liquid ventilation paO2, paCO2 and pH were within the normal range. The other methods of liquid ventilation led rapidly to hypercapnia and a drop of pH as well as to serious changes in the circulation (hypertension, bradyarrhythmia).

[Liquid ventilation--1]. / Kapalinová ventilace--1. cást.

The authors investigated in detail the sorption and desorption of oxygen and carbon dioxide in a solution of perfluorocarbons (solution RM 101, Miteni, Italy). From the results of the investigation ensues that maximal oxygen saturation of 77.3 vol.% can be achieved at 8 degrees C. With rising temperature the oxygen concentration in the solution declines (67.6 vol.% at 37 degrees). The saturation of the RM 101 solution corresponds to a linear equation of seventh order (fig. 2). Desorption of the RM 101 solution fully saturated with carbon dioxide, is on the other hand, most rapid at 37 degrees C (after the 13th minute the RM 101 solution contains less than 2% carbon dioxide as compared with 25 vol.% at 8 degrees C during the same period. In general the kinetics of desorption of carbon dioxide in solution correspond to a linear equation of fifth order (fig. 4). From the practical aspect it is not expedient to saturate the RM 101 solution with oxygen longer than 15-20 minutes. The mentioned kinetic parameters are important for the construction of a special liquid membrane or bubble oxygenator. In particular the latter is useful as with its use the authors achieved a 1.9 x higher oxygen concentration in the RM 101 solution than declared by the manufacturer.

Pneumatoamperometric determination of sulfur dioxide in air on ppb level.

A simple device for the determination of sulfur dioxide at ppb concentrations in air is described. The device is composed of an enrichment unit operating continuously on the basis of gas extraction into polydisperse aerosol of a liquid transferring sulfur dioxide from liter amount of air into microliter amount of liquid. The analyte is determined pneumatoamperically from the concentrate on a gold-plated porous Teflon electrode. The detection limit is 0.3 ppb (v), i.e. 0.87 microgram/m3 of sulfur dioxide, the linear range covers several orders of magnitude. The analytical response is obtained few tenths of seconds after the gas contaminated with sulfur dioxide has entered the enrichment unit.