Investigation of accelerated aging of lignin-containing polymer materials.

This paper presents the results of an accelerated aging test of biocomposites containing kraft lignin, where the resistance of the materials against humidity and light exposure was investigated. Low molecular weight lignin, modified with methacrylic anhydride (LWL-Met), was copolymerized with two commercial monomers: styrene (St) and methyl methacrylate (MMA). The biocomposites were obtained by a bulk polymerization method using α,α'-azoiso-bis-butyronitrile (AIBN) as a free radical polymerization initiator. The Shore D hardness of the obtained materials was determined before and after aging test. The changes in the chemical structures of polymers, as the result of aging were analyzed by using the attenuated total reflection Fourier transform infrared (ATR/FT-IR) spectroscopy method. The thermal behavior and stability of the obtained materials were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The surface topography was determined using the optical topography method to evaluate the changes on the surface of synthesized materials resulted from accelerated aging. Application of modified lignin as a biocomponent in the polymerization process and its influence on the properties of the obtained materials before and after the accelerated aging test are discussed.

Enhanced TLR2 responses in multiple sclerosis.

The roles of the microbiome and innate immunity in the pathogenesis of multiple sclerosis (MS) remain unclear. We have previously documented abnormally low levels of a microbiome-derived Toll-like receptor (TLR)2-stimulating bacterial lipid in the blood of MS patients and postulated that this is indicative of a deficiency in the innate immune regulating function of the microbiome in MS. We postulated further that the resulting enhanced TLR2 responsiveness plays a critical role in the pathogenesis of MS. As proof-of-concept, we reported that decreasing systemic TLR2 responsiveness by administering very low-dose TLR2 ligands attenuated significantly the mouse model of MS, experimental autoimmune encephalomyelitis. Studies of Toll-like receptor responses in patients with MS have been conflicting. Importantly, most of these investigations have focused on the response to TLR4 ligation and few have characterized TLR2 responses in MS. In the present study, our goal was to characterize TLR2 responses of MS patients using multiple approaches. Studying a total of 26 MS patients and 32 healthy controls, we now document for the first time that a large fraction of MS patients (50%) demonstrate enhanced responsiveness to TLR2 stimulation. Interestingly, the enhanced TLR2 responders include a significant fraction of those with progressive forms of MS, a subset of patients considered unresponsive to adaptive immune system-targeting therapies. Our results suggest the presence of a pathologically relevant TLR2 related innate immune abnormality in patients with both relapsing-remitting and progressive MS. These findings may have significant implications for understanding the role of innate immunity in the pathogenesis of MS.

Results of surgical treatment of cervical esophageal diverticula.

On the basis of 20 years' experience, the authors present the immediate and long-term results of operative treatment of Zenker's diverticulum. Comparison of two methods of surgery - diverticulopexia (in 21 patients) and excision (in 16), both associated with upper esophageal sphincter myotomy - shows good immediate and longterm results (from 1 to 19 years), with disappearance of symptoms (dysphagia) in all patients. There was no perioperative mortality. Postoperative complications were most commonly of pulmonary origin and were observed in a third of patients in both groups. In two patients from the group treated with excision, a leak from the suture line occurred, which healed spontaneously. These two patients had transient dysphagia in the postoperative period. On the basis of this analysis, the authors conclude that diverticulopexia is a safer surgical procedure than excision, giving less complications and a very good long-term functional result.

TEM studies of the nitrided/oxided Ni-Ti surface layer.

TiN and TiO(2) coatings, which are known from their low chemical reactivity, high hardness and wear and corrosion resistance, are used for protecting the NiTi surface. In the present work, nearly equiatomic NiTi (50.6 at.%) shape memory alloy was covered with the layers obtained by nitriding under glow discharge at 1073 K. Additionally, at the end of the process some amount of oxygen was added. Characterization of the nitrided/oxided layers structure was carried out using transmission and scanning electron microscopy. The investigations were focused on the structure of the multilayer nitrided/oxided NiTi surface. The surface is formed from nanocrystalline and columnar grains of the TiN phase. Between the top layer and beta-NiTi substrate the interface Ti(2)Ni layer was formed. Addition of oxygen at the end of the process created a thin layer of TiO(2) phase nanograins at the surface of the TiN phase. In the same areas, small amount of amorphous phase was identified. The combination of nitriding and oxidation formed layers that reveal relatively high corrosion resistance.

TEM studies of the nitrided Ni-Ti surface layer.

The structure of surface layer, obtained on the nearly equiatomic Ni-Ti alloy after nitriding under glow discharge conditions at temperatures 700 or 800 degrees C, was investigated. The structural characterization of the intruded layer was performed on cross-sectional thin foils by the use of the transmission and scanning electron microscopes. The obtained results show that the nitrided layers consist mainly of the nanocrystalline TiN phase and small amount of Ti(2)N. Between the nitrided layers and beta-NiTi matrix an intermediate Ti(2)Ni phase layer was observed.

Surgical results of leg amputation according to Ghormley's technique in the treatment of chronic lower limb ischaemia.

The authors present their experience in the treatment of chronic lower limb ischaemia resulting from atherosclerosis by below knee amputation according to Ghormley's technique, with the immediate application of a semi-rigid plaster cast and early rehabilitation. From a group of 664 patients requiring major amputations, 61 patients (52 men) aged 64 +/- 11 fulfilled the criteria for unilateral below-knee amputation for critical limb ischaemia for atherosclerosis consequences. Peri-operative (30-days) mortality was of 3.28%. Stump healing was very good or good (no need for further surgery) in over 2/3 of patients, but in 20% the need for above-knee amputation developed. Postoperative knee contracture (defined as 15 degrees or more limitation to the movement range) was observed in 11.5% of patients.

Serum cholesterol in cerebral malignancies.

Reduced blood cholesterol levels were reported in patients with a variety of malignant peripheral tumors. This fact is likely related to increased cholesterol demand by proliferating tumor cells. The question arises whether this 'tumor-associated hypocholesterolemia' occurs also in patients with brain tumors, and--if it does not--whether its absence can be related to the location of the tumors. We have compared fasting serum total cholesterol levels among three groups of patients: 52 patients with gliomas, 56 patients with symptomatic metastatic brain tumors, and 50 patients harboring malignant tumors of peripheral location but showing no clinical signs of brain metastases. Patients in the last group, despite being--on an average--more age-advanced, had lower total serum cholesterol levels than either the patients with gliomas, or the patients with brain metastases. No difference in the cholesterol levels was found between the two latter groups, and a majority of these patients had borderline or elevated cholesterol levels. This apparent absence of 'tumor-associated hypocholesterolemia' in brain tumor patients may be related to either brain tumors' ability to synthesize cholesterol de novo and their reduced dependence on peripheral cholesterol supply, the existence of brain tumor-blood barrier, effect of medications used to counteract brain edema and seizures, or a combination of these factors.

Results of surgical treatment of cervical esophageal diverticula.

On the basis of 20 years' experience, the authors present the immediate and long-term results of operative treatment of Zenker's diverticulum. Comparison of two methods of surgery--diverticulopexia (in 21 patients) and excision (in 16), both associated with upper esophageal sphincter myotomy--shows good immediate and long-term results (from 1 to 19 years), with disappearance of symptoms (dysphagia) in all patients. There was no perioperative mortality. Postoperative complications were most commonly of pulmonary origin and were observed in a third of patients in both groups. In two patients from the group treated with excision, a leak from the suture line occurred, which healed spontaneously. These two patients had transient dysphagia in the postoperative period. On the basis of this analysis, the authors conclude that diverticulopexia is a safer surgical procedure than excision, giving less complications and a very good long-term functional result.

[Treatment of liver injuries in personal clinical material from 1990-1996]. / Leczenie obrazen watroby w materiale wlasnym Kliniki w latach 1990-1996.

From 1990 to 1996 two hundred and sixteen patients with abdominal trauma were treated in our Department. In 170 cases there were blunt, and in 46-penetrating injuries (stab and gunshot wounds). Injuries of the other regions of the body coexisted in 117 patients (multiple trauma). In 42 cases (19.4%) abdominal trauma caused injury to the liver. In this group blunt mechanism of trauma also dominated (71%). The victims were usually young men (90% of the group, mean age - 35.3 years). The most common cause of injury were traffic accidents (47.6%), penetrating injury being the second commonest cause (12 patients i.e. 29%). Four patients were treated conservatively, the remaining 38 required surgical intervention. Most frequently liver suture and peritoneal drainage were performed (20), followed by liver tissue resections (16) and liver packing (12). Other surgical procedures to treat coexisting injuries were performed in 24 patients. In 22 patients postoperative complications occurred: liver abscess in 6 cases, hemorrhage in 4, wound infection in 4, biliary fistula in 2, intrahepatic aneurysm in 2 and other complications in 8 patients. The mean time of hospitalisation were of 20 days (range: 0-64 days). Mean volume of blood transfused equaled 6.9 U. There were 16 deaths (38%), in all cases in multiple trauma victims. All patients with penetrating liver trauma survived.

[Results of surgical treatment for Zenker's diverticula]. / Wyniki leczenia chirurgicznego uchylków Zenkera.

From 1976 to 1996, thirty nine patients were surgically treated for pharyngoesophageal diverticulum. The present study aimed to compare two methods of operative treatment of Zenker's diverticulum: excision (group I) and pexy, both of which were associated with upper esophageal sphincter myotomy. The main indication for surgery was dysphagia. The diagnosis of Zenker's diverticulum was based on clinical symptoms and the result of upper GI tract barium examination. In 75% of patients the diameter of diverticulum exceeded 2 cm. No patient died in the perioperative period. The main complications observed in the postoperative period were of pulmonary origin. In group I (excision) a leakage from the suture line occurred in 2 patients (12.5%). Time of follow-up ranged from 1 to 20 years (mean: 7 years). The comparison of both methods of treatment employed is in favour of diverticulopexy, being a safer and less complications-bearing method, although both of them give similar functional results.

[Esophageal resection for cancer--analysis of postoperative complications from personal materials]. / Resekcje przelyku z powodu raka--analiza powiklan pooperacyjnych w materiale wlasnym.

The aim of the present study was to analyse the rate of postoperative complications in patients after esophageal resection for cancer, as well as the dependence of its frequency from surgical tactics employed during the operation. Postoperative complications occurring in 38 patients who underwent esophagectomy and intrathoracic esophagogastric anastomosis (treated from 1978 to 1987) were compared with the same data of 74 patients (1988-1996) in whom the operation consisted of the total intrathoracic esophagectomy, cardia, lesser curvature of the stomach and large regional lymph nodes dissection. In these latter cases the esophagogastric anastomosis was performed in the neck. The most frequent postoperative complications in both groups were of cardiopulmonary origin. The anastomotic leak occurred less frequently in patients with cervical esophagogastric anastomosis. However, when occurred, healing was more likely by local drainage and conservative treatment. Anastomotic leaks after intrathoracic esophagogatric anastomoses were usually fatal. In these cases the only chance of patient's survival was an aggressive surgical treatment consisting of disconnection of alimentary tract: esophageal fistula in the neck and feeding jejunostomy.

Endoscopic laser treatment of benign tracheal stenoses.

We present the technique and results of endoscopic neodymium-yttrium aluminum garnet laser treatment of benign tracheal stenoses. This therapy was used in 15 patients with tracheal stenoses. Benign tracheal granulomas were caused by prolonged tracheal intubation in eight patients, permanent maintenance of tracheostomy tube in five patients, and nonspecific inflammatory process of the trachea in two patients. The clinical picture was dominated by dyspnea and stridor. The achievement of normal tracheal patency required several laser therapy sessions, repeated at 5- to 7-day intervals. In 30% of patients additional laser vaporization was required as well. The immediate and short-term results were encouraging; in all cases the normal tracheal lumen was restored, resulting in alleviation of patients' symptoms.

[Portal vein thrombosis. Etiology, diagnosis and treatment]. / Zakrzepica zyly wrotnej. Etiologia, diagnostyka i leczenie.

The authors present 225 patients with various forms of portal system venous thrombosis (PSVT), of various origin and etiology. The largest group (120 patients) were the young people suffering from portal hypertension due to pre-hepatic venous obstruction of uncertain etiology, lasting since childhood. The next group consisted of 75 patients with liver cirrhosis coexisting with PSVT. In other cases PSVT was diagnosed as coincident with: Budd-Chiari Syndrome (8 cases), liver tumors (9 cases), chronic pancreatitis (3 cases) and polycythaemia (2 cases). In 3 cases PSCT developed postoperatively and in 5 cases after oral contraceptives. Diagnosis of coexisting PSVT deteriorates the prognosis in liver cirrhosis. The overall mortality was 16%. The course of the disease depends on extensiveness and dynamism of thrombosis, but consequently leads to the development of portal hypertension. The most effective diagnostic procedures are: CT and USG with Doppler flowmetry. Bleeding esophageal varices require either sclerotherapy or surgical treatment--decompressive shunts or "non-shunt" procedures. In the cases of recent thrombosis, without bleeding varices, thrombolytic therapy appears to be effective.

[Endoscopic treatment of iatrogenic tracheal stenosis by laser Nd:YAG]. / Endoskopowe leczenie jatrogennych zwezen tchawicy laserem Nd:YAG.

The authors present the technique and results of endoscopic Nd:YAG laser treatment of inflammatory tracheal stenoses. This kind of therapy was employed in 10 patients with tracheal stenosis, resulting from long-term nastotracheal intubation (6 cases), tracheostomy tube after radical laryngectomy (3 cases) and tracheal trauma. The laser fiber was introduced into trachea by the operative channel of a flexible bronchoscope and vaporization of obstructing tissues carried out using contact method in continuous mode of light emission (power 7-20 Watts). The achievement of normal tracheal patency usually required several laser therapy sessions (3-5), repeated in 3-5 days intervals. The short-term results are encouraging: in all cases the normal tracheal was lumen was restored, resulting in alleviation of patients' symptoms. In 3 cases a recurrent tracheal stenosis, requiring additional laser treatment was observed.