Narrow line between benefit and harm: Additivity of hyperthermia to cisplatin cytotoxicity in different gastrointestinal cancer cells

AIM To investigate the response to hyperthermia and chemotherapy, analyzing apoptosis, cytotoxicity, and cisplatin concentration in different digestive system cancer cells.METHODS AGS(gastric cancer cell line), Caco-2(colon cancer cell line) and T3M4(pancreatic cancer cell line) were treated by cisplatin and different temperature setting(37 ℃ to 45 ℃) either in isolation, or in combination. Treatment lasted for one hour. 48 h after the treatment viability was evaluated by MTT, cell apoptosis by Annexin V-PE and 7 ADD flow cytometry. Intracellular cisplatin concentration was measured immediately after the treatment, using mass spectrometry. Isobologram analysis was performed to evaluate the mathematical combined effect of temperature and cisplatin.RESULTS AGS cells were the most sensitive to isolated application of hyperthermia. Hyperthermia, in addition to cisplatin treatment, did not provoke a synergistic effect at intervals from 37 ℃ to 41 ℃ in neither cancer cell line. However, a temperature of 43 ℃ enhanced cisplatin cytotoxicity for Caco-2 cells. Moreover, isobologram analysis revealed mathematical antagonistic effects of cisplatin and temperature combined treatment in AGS cells; variations between synergistic, additive, and antagonistic effects in Caco-2 cells; and additive and antagonistic effects in T3 M4 cells. Combined treatment enhanced initiation of cell apoptosis in AGS, Caco-2, and T3 M4 cells by 61%, 20%, and 19% respectively. The increase of intracellular cisplatin concentration was observed at 43 ℃ by 30%, 20%, and 18% in AGS, Caco-2, and T3 M4 cells, respectively.CONCLUSION In addition to cisplatin, hyperthermia up to 43 ℃ does not affect the viability of cancer cells in a synergistic manner.     

Study of the Course of Cement Hydration in the Presence of Waste Metal Particles and Pozzolanic Additives

As the construction of hydrotechnical and energy facilities grows worldwide, so does the need for special heavyweight concrete. This study presents the analysis of the influence of waste-metal particle filler (WMP) on Portland cement (PC) paste and mortars with pozzolanic (microsilica and metakaolin) additives in terms of the hydration process, structure development, and physical–mechanical properties during 28 days of hardening. Results have shown that waste-metal particle fillers prolong the course of PC hydration. The addition of pozzolanic additives by 37% increased the total heat value and the ultrasound propagation velocity (UPV) in WMP-containing paste by 16%; however, in the paste with only WMP, the UPV is 4% lower than in the WMP-free paste. The density of waste-metal particle fillers in the free mortar was about two times lower than waste-metal particle fillers containing mortar. Due to the lower water absorption, the compressive strength of WMP-free mortar after 28 days of hardening achieved 42.1 MPa, which is about 14% higher than in mortar with waste-metal particle filler. The addition of pozzolanic additives decreased water absorption and increased the compressive strength of waste-metal particle filler containing mortar by 22%, compared to pozzolanic additive-free waste-metal particle fillers containing mortar. The pozzolanic additives facilitated a less porous matrix and improved the contact zone between the cement matrix and waste-metal particle fillers. The results of the study showed that pozzolanic additives can solve difficulties in local waste-metal particle fillers application in heavyweight concrete. The successful development of heavyweight concrete with waste-metal particle fillers and pozzolanic additives can significantly expand the possibility of creating special concrete using different local waste. The heavyweight concrete developed by using waste-metal particle fillers is suitable for being used in load balancing and in hydrotechnical foundations.     

Cataracts are caused by alterations of a critical N-terminal positive charge in connexin50

PURPOSE: To elucidate the basis of the autosomal dominant congenital nuclear cataracts caused by the connexin50 mutant, CX50R23T, by determining its cellular distribution and functional behavior and the consequences of substituting other amino acids for arginine-23. METHODS: Connexin50 (CX50) mutants were generated by PCR and transfected into HeLa or N2a cells. Expressed CX50 protein was detected by immunoblot analysis and localized by immunofluorescence. Intercellular communication was assessed by microinjection of neurobiotin or by double whole-cell patch-clamp recording. RESULTS: HeLa cells stably transfected with CX50R23T or wild-type CX50 produced immunoreactive CX50 bands of identical electrophoretic mobility. Whereas HeLa cells stably expressing CX50 contained abundant gap junction plaques, CX50R23T localized predominantly in the cytoplasm. HeLa cells expressing wild-type CX50 showed large gap junctional conductances and extensive transfer of neurobiotin, but those expressing CX50R23T did not show significant intercellular communication by either assay. Moreover, CX50R23T inhibited the function of coexpressed wild-type CX50. Three CX50R23 substitution mutants (CX50R23K, CX50R23L, and CX50R23W) formed gap junction plaques, whereas two mutant substitutions with negatively charged residues (CX50R23D, CX50R23E) did not form detectable plaques. Only the mutant with a positive charge substitution (CX50R23K) allowed neurobiotin transfer at levels similar to those of wild-type CX50; none of the other mutants induced transfer. CONCLUSIONS: These results suggest that replacement of amino acid 23 in CX50 by any residue that is not positively charged would lead to cataract formation.     

Brushite mineralised Scots pine (Pinus sylvestris L.) sapwood – revealing mineral crystallization within a wood matrix by in situ XRD

Dicalcium phosphate dihydrate (CaHPO₄·2H₂O, DCPD, brushite) crystals were synthesised within Scots pine sapwood via a wet-chemistry route from aqueous solutions of Ca(CH₃COO)₂ and NH₄H₂PO₄ salts. SEM/EDS analysis was used to assess the saturation of the wood cell lumina and cell wall as well as morphological features and elemental composition of the co-precipitated mineral. Brushite mineral crystallization and crystallite growth within the wood matrix was studied by in situ XRD. The chemical composition of the mineral before and after the dissolution was evaluated using FTIR spectroscopy. The overall impact of brushite on the thermal behaviour of wood was studied by TGA/DSC and TGA/DTA/MS analysis under oxidative and pyrolytic conditions. Bending and compression strength perpendicular and parallel to the fibre directions as well as bending strengths in longitudinal and transverse directions of the mineralised wood were also evaluated. Results indicate the viability of the wet-chemistry processing route for wood reinforcement with crystalline calcium phosphate (CaP)-based minerals, and imply a potential in producing hybrid bio-based materials that could be attractive in the construction sector as an environmentally friendly building material.

Brushite mineral shows potential in wood reinforcement and development of hybrid calcium phosphate-based wood composites that could be particularly attractive in the construction sector as an environmentally friendly building material.     

Electrotonic modulation of cardiac impulse conduction by myofibroblasts

Structural remodeling of the myocardium associated with mechanical overload or cardiac infarction is accompanied by the appearance of myofibroblasts. These fibroblast-like cells express alpha-smooth muscle actin (alphaSMA) and have been shown to express connexins in tissues other than heart. The present study examined whether myofibroblasts of cardiac origin establish heterocellular gap junctional coupling with cardiomyocytes and whether ensuing electrotonic interactions affect impulse propagation. For this purpose, impulse conduction characteristics (conduction velocity [theta] and maximal upstroke velocity [dV/dtmax]) were assessed optically in cultured strands of cardiomyocytes, which were coated with fibroblasts of cardiac origin. Immunocytochemistry showed that cultured fibroblasts underwent a phenotype switch to alphaSMA-positive myofibroblasts that expressed connexin 43 and 45 both among themselves and at contact sites with cardiomyocytes. Myofibroblasts affected theta and dV/dtmax in a cell density-dependent manner; a gradual increase of myofibroblast-to-cardiomyocyte ratios up to 7:100 caused an increase of both theta and dV/dtmax, which was followed by a progressive decline at higher ratios. On full coverage of the strands with myofibroblasts (ratio >20:100), theta fell <200 mm/s. This biphasic dependence of theta and dV/dtmax on myofibroblast density is reminiscent of "supernormal conduction" and is explained by a myofibroblast density-dependent gradual depolarization of the cardiomyocyte strands from -78 mV to -50 mV as measured using microelectrode recordings. These findings suggest that myofibroblasts, apart from their role in structural remodeling, might contribute to arrhythmogenesis by direct electrotonic modulation of conduction and that prevention of their appearance might represent an antiarrhythmic therapeutic target.     

Site-specific DNA transesterification catalyzed by a restriction enzyme

Most restriction endonucleases use Mg2+ to hydrolyze phosphodiester bonds at specific DNA sites. We show here that BfiI, a metal-independent restriction enzyme from the phospholipase D superfamily, catalyzes both DNA hydrolysis and transesterification reactions at its recognition site. In the presence of alcohols such as ethanol or glycerol, it attaches the alcohol covalently to the 5' terminus of the cleaved DNA. Under certain conditions, the terminal 3'-OH of one DNA strand can attack the target phosphodiester bond in the other strand to create a DNA hairpin. Transesterification reactions on DNA with phosphorothioate linkages at the target bond proceed with retention of stereoconfiguration at the phosphorus, indicating, uniquely for a restriction enzyme, a two-step mechanism. We propose that BfiI first makes a covalent enzyme-DNA intermediate, and then it resolves it by a nucleophilic attack of water or an alcohol, to yield hydrolysis or transesterification products, respectively.     

Tumor-related factors and patient's age influence survival after resection for ampullary adenocarcinoma

BACKGROUND/PURPOSE: The majority of surgeons agree that ampullary adenocarcinoma should be removed by partial pancreatoduodenectomy. Favoring extended resection, based on the uncertainty of the preoperative diagnosis and the higher probability of clear resection margins, we aimed to disclose the results of this surgical procedure in terms of postoperative morbidity and mortality, and to identify prognosticators of long-term survival. METHODS: We documented, prospectively, 25 consecutive patients with adenocarcinoma of the papilla of Vater in whom pylorus-preserving pancreatoduodenectomy was performed. Clinical data, pathology reports, International Union Against Cancer (UICC) tumor stage, postoperative morbidity, mortality, and long-term follow-up results were evaluated. The Kaplan-Meier method and log-rank test were applied for univariate analysis. The Cox proportional hazard model was used for multivariate analysis. RESULTS: Postoperative mortality was 4%, overall morbidity was 32%, and pancreas-associated morbidity was 8%. Mean survival time was 53.8 months. Tumor size, N status, UICC stage, lymphatic invasion, blood vessel infiltration, R0 resection, and age of patient at the cutoff of 70 years were independent predictors of survival on univariate analysis. Multivariate analysis, however, disclosed no independent predictors of prognosis. CONCLUSIONS: Pancreatoduodenectomy for ampullary carcinoma is reasonable in terms of postoperative morbidity and mortality. Tumor-related factors, R0 resection, and advanced age appeared as the main predictors of survival.     

Heart Rhythm Control During Sleep

Heart rate (HR) changes during sleep were analyzed, with the aid of a minicomputer, for a group of 20 healthy subjects. In stages 1, 2, 3, and 4, HR decreased against a background of increasing respiratory arrhythmia. REM sleep was characterized by increased HR and decreased respiratory arrhythmia. HR changes during sleep were dependent on the subject's initial autonomic HR control level. The evidence from 3 healthy subjects, who were studied under baseline conditions, propranolol (a sympatholytic agent), atropine (a parasympathetic depressant), and propranolol plus atropine, showed that the HR decrease during stages 1, 2, 3, and 4 is caused by augmented parasympathetic input. The HR increase during REM sleep is due to a reduction in parasympathetic control. The sympathetic input remains relatively constant throughout all stages of sleep, except for its decrease during stage 1.