Mechanical coupling in homogeneously deformed single-wall carbon nanotubes.

We developed a full symmetry implementing method, based on classical molecular dynamics with the Brenner-Tersoff potential, for determining the optimal configuration of homogeneously deformed infinitely long single-wall carbon nanotubes. All nanotubes with diameter less than 1.3 nm are studied. Systematic analysis of the coupling between different types of deformation shows that, in the tubes with chiral angle close to zero and 30°, the torsion-induced circumferential strain is opposite to the induced axial strain. Also, torsion in zigzag tubes induces larger circumferential strain, but in armchair tubes it yields a larger axial strain. The influence of diameter on axial-stretching-induced torsion becomes significant only for narrow tubes. Finally, significant deviation from the linear dependence of axial-strain-induced radial deformation is found for zigzag tubes. The presented results are important for the calculation of electro-optical properties of nanotubes under strain.

Natural torsion in chiral single-wall carbon nanotubes.

Optimizations performed with two geometrical, molecular mechanical and density functional models show that the configuration of single-wall carbon nanotubes is slightly twisted with respect to that predicted by conventional techniques. Geometrical models are used to explain the effect by breaking of local symmetry of the equally distant neighbors in graphene in the course of rolling, which is minimized by torsion. The torsion angle is small, and decreases with nanotube diameter, being less than 1° Å(-1) for ultrathin tubes. Therefore this effect can be hard to observe in experiments. Still, we single out features in diffraction patterns which can distinguish between twisted and non-twisted configurations. In addition, torsion makes a blue shift in the radial breathing mode, which for thin tubes can be seen by Raman measurement. The effect is slightly strengthened at room temperature.

The carcinostatic and proapoptotic potential of 4-hydroxynonenal in HeLa cells is associated with its conjugation to cellular proteins.

BACKGROUND: Previous studies have shown that the lipid peroxidation product 4-hydroxynonenal (HNE) acts as a cell growth modulator if used at low, physiological concentrations being strongly cytotoxic at higher concentrations for a number of cells. These effects of HNE also appeared to be mutually dependent on the effects of serum growth factors. The aim of this investigation was to study the concentration-dependent response of human cervical carcinoma (HeLa) cells in vitro with respect to the intracellular uptake of exogenous HNE, the cellular energy metabolism, DNA synthesis, overall gene expression and susceptibility to apoptosis. MATERIALS AND METHODS: MTT assay was applied as an index of energy metabolism and the replicative activity was quantitated by the 3H-thymidine incorporation assay. The occurence and intracellular distribution was studied with monoclonal antibodies directed against HNE-protein conjugates. Binding of HNE to serum proteins was determined with the same antibodies by Western blotting. Differential gene expression was studied by differential display RT-PCR while a novel photometric assay, denoted Titer-TACS, was used for in situ detection and quantitation of apoptosis in monolayer cell cultures. RESULTS: A physiological concentration of HNE (1 microM) had hardly any effect on the parameters of the replicative activity and the energy metabolism. No morphological changes were observed and the number of HNE-positive cells was not significantly different when compared to the untreated control cells, while most of the aldehyde appeared to be bound to serum proteins (albumin fraction). A ten-fold higher concentration (10 microM) was found to be cytostatic. Spindle-shaped cells with a picnotic nucleus were observed occasionally, as well as membrane blebs, which were HNE-positive. The number of HNE-positive cells was significantly increased compared both to the control cells and cells treated with 1 microM HNE, but in the presence of serum the effects of 10 microM HNE were negated due to its binding to the serum proteins. Finally, 100 microM HNE was cytotoxic for the HeLa cells. Most of the cells were picnotic, together with a few spindle-shaped or oval cells. The staining for HNE was diffuse and strong (90% of the cells were HNE-positive) while even binding of the aldehyde to serum proteins did not prevent its cytotoxic effects. This concentration of HNE caused acute stress response of the cells resulting in the decreased expression of several as yet unidentified genes. The altered pattern of gene expression was followed by programmed cell death, i.e. an increased number of apoptotic cells after treatment with low (1 and 10 microM) concentrations of HNE. A rebound effect was observed, i.e. a decrease of apoptotic cells after 24 hours followed by an overshooting increase after 48 hours. CONCLUSIONS: For HeLa carcinoma cells there appears to be a concentration range of HNE where it does not cause necrosis but preferentially apoptosis. At this concentration range HNE is cytochemically detectable within the cells as a protein conjugate. It is proposed that a possible differential sensitivity of cancer cells and their normal counterparts to the cytostatic activity of HNE should be explored.

Symmetry of single-wall nanotubes.

Nanotubes have become attractive subjects in solid-state physics owing to their potential applications in nanotechnology. Their symmetry is one of the important tools in theoretical investigations. Here a review is presented of the symmetry groups of the single-wall nano- and microtubes considered in literature: BN, GaN, MS2, C, BC3, BC2N.

An overview on anticancer activities of the Viscum album extract Isorel.

The activity principle of the mistletoe (Viscum album L.) phytotherapeutics could be considered as combined cytotoxic and "biological response modifying" activities (increasing host defense against cancer) that result from the activities of the plant lectins and the other biologically relevant substances. We found before that the aqueous extract Isorel, produced by Novipharm GmbH (Pörtschach, Austria) from the entire plant (planta tota) of fresh mistletoe under standardized conditions with bioassay validated batch consistency, can be valuable in experimental adjuvant cancer therapy increasing efficiency of cyclophosphamide chemotherapy. In current study we found that Isorel increases the reactivity of the tumor-bearing mice lymphocytes to the mitogens (ConA and LPS) in vitro, thus indicating its immune stimulating effects for the cancer-immunosuppressed lymphocytes. Moreover, Isorel inhibited the incorporation of 3H-labelled amino acids (protein synthesis) in various malignant cell lines. For the growth inhibition mostly higher MW components were responsible, although even less than 500 Da components were also active. We further analyzed the effects of drug application in vicinity of tumor (murine mammary carcinoma) and compared it with systemic effects. The animals carried mammary carcinoma in both hind limbs and were also injected with tumor cells i.v. to develop artificial lung metastases. Isorel was applied only at the right side (in the limb distal from the tumor) and caused persistent and almost complete inhibition of the tumor growth for 2/7 animals. Anticancer effects were less pronounced on the contralateral side tumors, although tumor growth rate was transiently reduced for some mice. Histology revealed that Isorel treatment, both at the side of tumor and systemically, increased the incidence of apoptosis and necrosis in the tumors, while reduction of mitosis was noticed only for the tumors in vicinity of the tumor exposed to Isorel. Finally, animals treated with Isorel had, on the average, three times less lung metastases than the controls. Thus, we conclude that both local and systemic effects of the application of Isorel could be of benefit for the tumor-bearing organism resulting in immunomodulation combined with tumor growth inhibition and reduction of metastases. According to the in vitro results, antitumorous effects could be the result not only of the mistletoe lectins and the other high MW factors, but also of the very low MW (< 500 Da) substances that deserve further analyses.

Clinical performance of the new cardiac markers troponin T and CK-MB on the Elecsys 2010. A multicentre evaluation.

Elecsys assays for the cardiac markers Troponin T (cTnT) and CK-MB have been evaluated in an international multicenter study on the random access analyzer Elecsys 2010 to characterize their clinical performance and their comparability with respective established routine methods. In method comparison studies of Elecsys Troponin T (TnT) with Enzymun-Test TnT, good correlations (r > or = 0.95) and a high degree of correspondence (slopes in 4 laboratories between 0.95 and 1.05) were found. The method comparison studies of Elecsys CK-MB with various CK-MB routine methods lead to good correlations but some systematic deviation in the slopes due to varying standardization. In a reference population of 350 persons upper reference limits (97.5th percentile) of 0.03 milligrams/l for Elecsys TnT and 3.1 milligrams/l for Elecsys CK-MB were found. In cardiosensitivity studies the equivalent diagnostic information of the new Elecsys assays to routine methods was confirmed in the early diagnosis of acute myocardial infarction (AMI), the detection of minor myocardial damages in patients with unstable angina pectoris (UAP) and in time course data monitoring of AMI and bypass surgery patients. The superior sensitivity of cTnT versus CK-MB has been established in a screening situation where in 29 patients with cardiac diseases only cTnT, but not CK-MB, was found pathologically increased; this was due either to the larger diagnostic window of cTnT in AMI or to the more sensitive recognition of minor myocardial damage. In the same study, the cardiospecificity of Elecsys TnT was found to be at least 99.5%. This has also been demonstrated in an earlier study for Enzymun-Test TnT. Further cardiospecificity testing, e.g. in renal failure patients, showed results equivalent to those of Enzymun-Test TnT. An extended clinical study involving 294 patients with chest pain, of whom 58 had a final diagnosis of AMI, revealed highly comparable sensitivity and specificity for the Elecsys assays and routine methods. Thus, the already recommended clinical cut-off values of 0.1 milligrams/l for cTnT and 5 milligrams/l for CK-MB are also valid for the Elecsys assays. The slightly improved sensitivity of Elecsys TnT in the lower range even allows the recognition of pathological increase at cTnT concentrations below 0.1 milligrams/l in special situations with sufficient additional clinical information. Summarizing, provide the two cardiac markers on the Elecsys 2010 at least equivalent or even superior diagnostic information in various clinical situations of cardiac disease compared with routine methods. The short turn-around time and reliable performance qualify the Elecsys assays as new methods of choice for routine and emergency use.

[60 years' of the modern hospital in Pozega]. / 60 godina moderne bolnice u Pozegi.

The development of the hospital in Pozega, from medieval poor houses to the establishment of a modern hospital in 1936, is presented. In the late 19th and early 20th century, surgery departments were founded in many hospitals in Slavonia. The old town hospital built in 1836 did not meet the demands of medical work, and in the period from 1930 to 1936 a new hospital building was constructed. Since then, the hospital has played a major role in health education and promotion, prevention and treatment of disease, and training of medical staff. After 1961 new departments were established (pediatrics, gynecology, otorhinolaryngology), and in 1981 a new surgery was built with seven operation rooms, as well as a modern intensive care unit, delivery rooms etc. These developments contributed to good hospital functioning during the war in 1991-1992. The hospital reconstruction with equipment renewal is now under way. Education of medical staff and scientific activities are continuing tasks which must accompany advances in medicine.

Acute renal failure as a complication of acute pancreatitis.

To assess the prevalence of acute renal failure (ARF) in patients with acute pancreatitis, as well as the factors predictive of a lethal outcome, we retrospectively studied the data of all patients admitted to our hospital over a 5-year period. Between 1989 and 1993, 554 patients presented with acute pancreatitis, of which 24 (4.4%) subsequently developed ARF. Death occurred in 14/24 (58%) of patients with ARF, and was associated with an increased incidence of multiorgan failure. There was no statistically significant difference in the age, admission blood pressure, or admission pulse rate of the patients who survived and those who died. In contrast, death was associated with a higher Ranson score, and the increased prevalence of multiorgan failure. The length of hospitalization of the nonsurviving group was significantly shorter. Acute renal failure is not a common finding in patients with acute pancreatitis. However, when it occurs, it is associated with a poor prognosis, and is predicted by a higher Ranson score and the presence of multiorgan failure.

[Primary actinomycosis of the liver--case report]. / Primarna aktinomikoza jetara--prikaz slucaja.

The liver is a rare site of actinomycotic abscess localization. A 36-year-old man admitted to the hospital because of pain under the right costal margin with skin hyperemia and edema in that region is presented. Clinical and laboratory examinations disclosed liver actinomycotic abscess. Surgical drainage was done followed by 8 months of antibiotic (penicillin) therapy. Discussed are the difficulties in diagnostic procedure and the lack of consensus in the therapeutic approach.