Dose-dependent induction of both pepsinogen-altered pyloric glands and adenocarcinomas in the glandular stomach of C3H mice treated with N-methyl-N-nitrosourea

BACKGROUND: Cigarette smoking has been shown to increase oxidative DNA damage in human sperm cells. Assessment of the role of cigarette smoking in the etiology of childhood cancer has focused primarily on the effect of maternal smoking. Similar studies in relation to paternal smoking, however, have been inconclusive. Few studies have evaluated the effect of paternal smoking in the preconception period, and most of these could not disentangle the effects of paternal from maternal smoking. PURPOSE: We investigated the relationship of paternal smoking, particularly in the preconception period, with childhood cancer among offspring of the nonsmoking mothers. METHODS: We conducted a population-based, case-control study in Shanghai, People's Republic of China, where the prevalence of smoking is high among men but extremely low among women. The study included 642 childhood cancer case patients (<15 years of age) and their individually matched control subjects. Information concerning parental smoking, alcohol drinking, and other exposures of the index child was obtained by direct interview of both parents of the study subjects. Odds ratios (ORs), derived from conditional logistic regression models, were used to measure the association between paternal smoking and risk of childhood cancers. RESULTS AND CONCLUSIONS: Paternal preconception smoking was related to a significantly elevated risk of childhood cancers, particularly acute leukemia and lymphoma. The risks rose with increasing pack-years of paternal preconception smoking for acute lymphocytic leukemia (ALL) (P for trend = .01), lymphoma (P for trend = .07), and total cancer (P for trend = .006). Compared with children whose fathers had never smoked cigarettes, children whose fathers smoked more than five pack-years prior to their conception had adjusted ORs of 3.8 (95% confidence interval [CI] = 1.3-12.3) for ALL, 4.5 (95% CI = 1.2-16.8) for lymphoma, 2.7 (95% CI = 0.8-9.9) for brain tumors, and 1.7 (95% CI = 1.2-2.5) for all cancers combined. Statistically significant increased risks of cancer were restricted to children under the age of 5 years at diagnosis or those whose fathers had smoked during all of the 5 years prior to conception. IMPLICATIONS: Further studies are needed to confirm the association of paternal smoking with increased risk of cancer in offspring, to clarify the pattern of risks in relation to the timing of cigarette smoking, and to elucidate the biologic mechanism involved in predisposing the offspring to cancer. For example, it may be that paternal smoking induces prezygotic genetic damage that, in turn, acts as the predisposing factor.     

Clonal composition of malignant fibrous histiocytoma: analysis by PCR-based assay of the human androgen receptor gene (HUMARA)

Poly(A)+ mRNA was isolated from leaves of potato plants (Solanum tuberosum L. cv. Desiree) according to standard protocols. This poly(A)+ mRNA was injected via glass microcapillaries into oocytes that were surgically removed from the African clawed toad Xenopus laevis. As a control, oocytes were either injected with H2O or remained untreated. Three days after injection the oocytes were analyzed by two electrode voltage clamping. Current voltage analysis revealed that a K+ channel from potato was functionally expressed in injected oocytes. The identity of this K+ channel was confirmed by its substrate specificity and a shift in the reversal potential. In particular, when the outside K+ concentration was increased the reversal potential of poly(A)+ injected oocytes shifted to more positive values. Furthermore, K+ outward currents declined when the outside K+ concentration was raised from 0.1 to 100 mM. Inward currents increased with an elevation of the K+ concentration. Several pharmaceuticals were tested for their potential to block this K+ channel. As a result, the channel was completely blocked by BaCl2. A three state reaction kinetic model was used to simulate the currents through the K+ transport protein as function of the extracellular K+ concentration. In particular, the simulation revealed current voltage relations that exactly matched the measured ones. Saturation of current voltage curves emerged from the simulation as a consequence of high extracellular potassium concentration.     

Appraisal of a manual blunt dissection for an intraoperative diagnosis of extrahepatic cancer invasion

BACKGROUND/AIMS: Liver cancer extension to the adjacent organs does not necessarily indicate tumor invasion. It is very hard to diagnose extrahepatic cancer invasion to the adjacent organs using preoperative imaging. This study was undertaken, therefore, to determine the real cancer invasion using a manual dissection. METHODOLOGY: Of the 51 consecutive patients with liver cancer, 6 cases with extrahepatically growing tumors were suspected to have cancer invasion both preoperatively and intraoperatively. Thus, we diagnosed whether or not any real extrahepatic cancer invasion was present by either removing the tumour by hand or by performing a blunt gauze dissection. RESULTS: Three hepatocellular carcinomas and one metastatic cancer were stripped off from the adjacent organ using a manual blunt dissection. However, the other two tumors could not be removed in the same manner and therefore a combined resection of the invaded portion had to be performed along with the hepatectomy. A postoperative detailed pathological examination revealed no cancer cells on the surface of the adjacent organ in the former 4 tumors. Cancer invasion was recognized, however, on the outside of the liver in the latter 2 combined resected tumors. CONCLUSIONS: An accurate intraoperative diagnosis of extrahepatic cancer invasion can be made using manual blunt dissection.     

A backward extrusion analysis by the rigid–plastic integralless–meshless method

The rigid–plastic integralless–meshless method is applied to the analysis of plane strain backward extrusion. The rigid–plastic integralless–meshless method, based on the moving least squares approximation and the partial differential equations of mechanical equilibrium, is a truly meshless method. In addition, since there is no any integration in the formulation of the rigid–plastic integralless–meshless method, this method is also an integralless method. Compared with the conventional rigid–plastic FEMs, the rigid–plastic integralless–meshless method has some advantages that are briefly no mesh generation, no remeshing and no integration. Compared with BEMs and FBEMs, the rigid–plastic integralless–meshless method is found to have some merits such as sparse matrix, no singularity, no integration and no fundamental solution. Contours of the equivalent strain rate, the equivalent strain, the equivalent stress and the shear stress, etc. of the backward extrusion analysis using the rigid–plastic integralless–meshless method are obtained successfully.     

Catching a molecule at the air-water interface: Dynamic pore array for molecular recognition

As a soft and flexible porous structure, a pore array of a steroid cyclophane SC(OH), which consists of the rigid 1,6,20,25-tetraaza[6.1.6.1]paracyclophane ring connected to four steroid moieties (cholic acid) through flexible L-lysine spacers, was prepared at the air-water interface. As confirmed by surface pressure (π)-molecular area (A) isotherms, transition between open conformation and cavity conformation of the SC(OH) molecule was reversibly induced upon repeated compression and expansion of its monolayer at pH 11 where amino groups of the lysine residues are not fully deprotonated. Capture and release of an aqueous fluorescent guest (TNS) by SC(OH) was observed upon dynamic cavity formation through surface fluorescence spectroscopy. At pH 12, dynamic cavity formation of SC(OH) was sufficiently suppressed, and the capture and release of an aqueous TNS by the monolayer was not virtually observed. Lessened electrostatic repulsion between the SC(OH) molecules due to conversion of ammonium to free amine may prevent the cavity from reopening. The importance of dynamic nature of cavity formation on the guest binding was also proved by control experiments using SC(H), which cannot form cavity conformation at any surface pressures at both pH 11 and 12.     

Poly(L‐lactide). X. Enhanced surface hydrophilicity and chain‐scission mechanisms of poly(L‐lactide) film in enzymatic,alkaline, and phosphate‐buffered solutions

Attempts were carried out to enhance the surface hydrophilicity of poly(L ‐lactide), that is, poly(L ‐lactic acid) (PLLA) film, utilizing enzymatic, alkaline, and autocatalytic hydrolyses in a proteinase K/Tris–HCL buffered solution system (37°C), in a 0.01N NaOH solution (37°C), and in a phosphate‐buffered solution (100°C), respectively. Moreover, its chain‐scission mechanisms in these different media were studied. The advancing contact‐angle (θ_a) value of the amorphous‐made PLLA film decreased monotonically with the hydrolysis time from 100° to 75° and 80° without a significant molecular weight decrease, when enzymatic and alkaline hydrolyses were continued for 60 min and 8 h, respectively. In contrast, a negligible change in the θ_a value was observed for the PLLA films even after the autocatalytic hydrolysis was continured for 16 h, when their bulk M_n decreased from 1.2 × 10⁵ to 2.2 × 10⁴ g mol^?1 or the number of hydrophilic terminal groups per unit weight increased from 1.7 × 10^?5 to 9.1 × 10^?5 mol g^?1. These findings, together with the result of gravimetry, revealed that the enzymatic and alkaline hydrolyses are powerful enough to enhance the practical surface hydrophilicity of the PLLA films because of their surface‐erosion mechanisms and that its practical surface hydrophilicity is controllable by varying the hydrolysis time. Moreover, autocatalytic hydrolysis is inappropriate to enhance the surface hydrophilicity, because of its bulk‐erosion mechanism. Alkaline hydrolysis is the best to enhance the hydrophilicity of the PLLA films without hydrolysis of the film cores, while the enzymatic hydrolysis is appropriate and inappropriate to enhance the surface hydrophilicity of bulky and thin PLLA materials, respectively, because a significant weight loss occurs before saturation of θ_a value. The changes in the weight loss and θ_a values during hydrolysis showed that exo chain scission as well as endo chain scission occurs in the presence of proteinase K, while in the alkaline and phosphate‐buffered solutions, hydrolysis proceeds via endo chain scission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1628–1633, 2003     

Fracture toughness of silica particulate‐filled epoxy composite

The relationship between the postcuring conditions and fracture toughness on three silica particulate‐filled epoxy composites was investigated. The glass transition temperature, T_g, and the fragility parameter, m, derived from the thermo‐viscoelasticity, were used to characterize the composites, which were postcured under various conditions. The glass transition temperature and fragility both depended on both of the curing conditions and the volume fraction of silica particles. The glass transition temperature increased with the postcuring time and temperature, while the fragility generally decreased as the volume fraction increased. There was no direct correlation between the glass transition temperature and fragility. The fracture toughness depended on both the glass transition temperature and fragility. The composites with a high glass transition temperature and low fragility had high fracture toughness. These results indicate that the glass transition temperature and fragility are useful parameters for estimating the fracture toughness of the silica particulate‐filled epoxy composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2261–2265, 2002     

Electrochemical formation of AlN in molten LiCl-KCl-Li3N systems

Electrochemical formation of aluminum nitride was investigated in molten LiCl-KCl-Li₃N systems at 723 K. When Al was anodically polarized at 1.0 V (versus Li⁺/Li), oxidation of nitride ions proceeded to form adsorbed nitrogen atoms, which reacted with the surface to form AlN film. The obtained nitrided film had a thickness of sub-micron order. The obtained nitrided layer consisted of two regions; the outer layer involving AlN and aluminum oxynitride and the inner layer involving metallic Al and AlN. When Al electrode was anodically polarized at 2.0 V, anodic dissolution of Al electrode occurred to give aluminum ions, which reacted with nitride ions in the melt to produce AlN particles (1-5 μm of diameter) of wurtzite structure.     

Stabilization of poly(vinyl chloride). I. Change in color of poly(vinyl chloride) compounded with some metal soaps

Poly(vinyl chloride) (PVC) with one or more metal salts added was colored by the action of heat to investigate the stabilization mechanism. The coloration and the color difference of heated PVC compound films varied according to the metal salt added. The decoloration of the colored compound films was advanced markedly in THF, DMF, acetone, and ammonia. On the other hand, the heated achromatic PVC film containing Cd/Ba soaps underwent an opposite change, from colorless to yellow orange, in the above materials. This means that the coloration of heated compound films may result from the formation of some complex (for example, π complex of the polyene with the metal chloride). Furthermore, the colored film with cadmium stearate was decolored by roll mixing with the colored film containing barium stearate. These results indicate that the stabilization with metal soaps may be founded on a physical phenomenon such aa an effect of complementary color.     

Phase Separation in Gelling Silica–Organic Polymer Solution: Systems Containing Poly(sodium styrenesulfonate)

Phase separation which occurs in parallel to the hydrolysis and gelation of alkoxysilane solution containing poly(sodium styrenesulfonate) (NaPSS) has been investigated. Depending on the reaction conditions, gel morphologies such as isolated pores, particle aggregates, and interconnected continuous pores from 0.1 to 100 μm long have been observed. Time-resolved light scattering of gelling solution suggested the occurrence of spinodal phase separation through the polymerization of silica and the subsequent freezing of the developing structure by sol-gel transition. The effects of reaction parameters on the periodic size are explained mainly in terms of their influence on the "chemical cooling" rate which is determined by the polymerizatica rate of silica and the solubility of NaPSS in the reacting solution.