Acquisition Of Character Research Articles

Prediction of lymph node metastasis and perineural invasion of biliary tract cancer by selected features from cDNA array data 1

To better understand the nature of the malignancy of biliary tract carcinoma and evaluate the feasibility of its prediction by gene expression profiles. We explored the gene expression profiles characteristic of progression and invasiveness in the cDNA array data obtained from 37 biliary tract carcinomas (15 bile duct, 11 gallbladder, 11 of ampulla of Vater). We pre-selected 51 and 100 genes for the presence versus absence of lymph node metastasis and perineural invasion on the basis of statistical difference. To search optimized sets of genes for prediction, we applied a sequential forward feature selection, minimizing leave-one-out error rates on a k-nearest neighbor classifier. We could predict lymph node metastasis and perineural invasion with an accuracy of 94 and 100%, respectively. When the 6-stage IA cancers without perineural invasion were precluded, a marked difference in gene expression (147 gene), discriminable with 100% accuracy, was noted between positive versus negative perineural invasion, suggesting that the acquisition of invasive character is rather a later molecular pathological event in biliary tract cancer. The present method provides a powerful means of classifying biliary tract carcinomas. We also suggest that perineural invasion is an important target of array databased pattern classification, which may predict patient outcomes and facilitate the determination of the extent of surgery to minimize the risk of recurrence.

Carácter moral y deberes éticos

Proponents of virtue ethics usually charge Kantian ethics with being act-centered because, they claim, its main object of moral evaluation are particular acts. This has the unwelcome consequence that an act can be morally worthy though the character who performs it is not virtuous. They also claim that ethics should focus on the character of persons such that only those acts that are the expression of a virtuous characters can be morally good. My purpose in this article is to show that the main object of moral evaluation in Kantian ethics is the character of persons. The categorical imperative does not demand the performance of particular acts, but the adoption of maxims of ends, which maxims are principles to guide a complete life. I claim that the adoption of such maxims necessarily requires the acquisition of a virtuous character so that whoever commits herself to living according to ethical principles both performs good acts and acquires a virtuous character.

Return of de-differentiation: why cancer is a developmental disease.

Many important advances have been made in the phenotypic and genetic characterization of malignant tumors since the publication of Peter Nowell's seminal article on the origin of cancer, but there has been no consistent effort to incorporate this wealth of knowledge into a general model of carcinogenesis. Current theoretical discussions on cancer are frequently dominated by attempts to categorize genetic alterations and phenotypic characteristics and establish correspondences between them. In this article, I argue, on the basis of recent data as well as "old" observations, that a developmental error leading to the acquisition of a unique cell character (de-differentiation) underlies all phenotypic characteristics of cancer cells and discuss how this notion can be reconciled with Nowell's model of carcinogenesis as a microevolutionary process into an updated theoretical description of cancer.

Vitamin A Deficiency Results in the Dose-Dependent Acquisition of Anterior Character and Shortening of the Caudal Hindbrain of the Rat Embryo

The developing nervous system is particularly vulnerable to vitamin A deficiency. Retinoid has been proposed to be a posteriorizing factor during hindbrain development, although direct evidence in the mammalian embryo is lacking. In the present study, pregnant vitamin A-deficient (VAD) rats were fed purified diets containing varying levels of all-trans-retinoic acid (atRA; 0, 0.5, 1.5, 6, 12, 25, 50, 125, or 250 μg/g diet) or were supplemented with retinol. Hindbrain development was studied from embryonic day 10 to 12.5 (∼6 to 40 somites). Normal morphogenesis was observed in all embryos from groups fed 250 μg atRA/g diet or retinol. The most caudal region of the hindbrain was the most sensitive to retinoid insufficiency, as evidenced by a loss of the hypoglossal nerve (cranial nerve XII) in embryos from the 125 μg atRA/g diet group. Further reduction of atRA to 50 μg/g diet led to the loss of cranial nerves IX, X, XI, and XII and associated sensory ganglia IX and X in all embryos as well as the loss of hindbrain segmentation caudal to the rhombomere (r) 3/4 border in a subset of embryos. Dysmorphic orthotopic otic vesicles or immature otic-like vesicles in both orthotopic and caudally ectopic locations were also observed. As the level of atRA was reduced, a loss of caudal hindbrain segmentation was observed in all embryos and the incidence of otic vesicle abnormalities increased. Perturbations in hindbrain segmentation, cranial nerve formation, and otic vesicle development were associated with abnormal patterning of the posterior hindbrain. Embryos from VAD dams fed between 0.5 and 50 μg atRA/g diet exhibited Hoxb-1 protein expression along the entire neural tube caudal to the r3/r4 border at a time when it should be restricted to r4. Krox-20 protein expression was expanded in r3 but absent or reduced in presumptive r5. Hoxd-4 mRNA expression was absent in the posterior hindbrain, and the rostral limit of Hoxb-5 protein expression in the neural tube was anteriorized, suggesting that the most posterior hindbrain region (r7/r8) had been deleted and/or improperly patterned. Thus, when limiting amounts of atRA are provided to VAD dams, the caudal portion of the hindbrain is shortened and possesses r4/r5-like characteristics, with this region finally exhibiting r4-like gene expression when retinoid is restricted even more severely. Thus, regions of the anterior hindbrain (i.e., r3 and r4) appear to be greatly expanded, whereas the posterior hindbrain (r5–r8) is reduced or absent. This work shows that retinoid plays a critical role in patterning, segmentation, and neurogenesis of the caudal hindbrain and serves as an essential posteriorizing signal for this region of the central nervous system in the mammal.

Aberration of p53 and DCC in gastric and colorectal cancer.

We investigated the expression of p53 protein by immunohistochemistry and the expression of deleted in colorectal carcinoma (DCC) mRNA by the reverse transcription-polymerase chain reaction (RT-PCR) method in surgically resected tumors of gastric and colorectal cancers and compared these results to the clinicopathological features. Positive immunoreactions of p53 were observed in 21 of 42 gastric cancers (50%) and 25 of 37 colorectal cancers (67.6%). Decreased expression of DCC mRNA was observed in 15 of 38 gastric cancers (39.5%) and 10 of 28 colorectal cancers (35. 7%). There was a significant correlation between the immunoreaction of p53 and the depth of tumor invasion in gastric cancer, as well as between the decreased expression of DCC mRNA and nodal metastasis in colorectal cancer. In early cases without metastasis and invasion beyond muscularis propria, none of six gastric cancers showed a p53 immunoreaction, while seven of 9 colorectal cancers showed positive immunoreactions. On the other hand, two of 4 gastric cancers showed decreased expression of DCC mRNA; whereas, none of the seven colorectal cancers did. Alteration of p53 might occur at a later stage in gastric cancer than in colorectal cancer and be associated with the acquisition of an invasive character. In contrast to gastric cancer, decreased expression of DCC mRNA might be present in a later stage in colorectal cancer than in gastric cancer, and be related to the acquisition of metastatic character to the lymph nodes. In conclusion, alterations of p53 or DCC may play different roles in the progression of gastric cancers as compared to colorectal cancers, and the occurrence of both p53 and DCC genes mutations may cause these cancers to become more malignant.

Mesenchyme to epithelium transition during development of the mammalian kidney tubule.

Kidney epithelia have two separate origins. Collecting ducts develop in the manner of most glandular organs, by growth and branching of a bud derived from a pre-existing epithelium. Excretory tubules develop by a direct mesenchyme to epithelium transition (MET), which is induced by the tips of the developing collecting duct system as it invades a specialised area of mesenchymal cells. The process by which these metanephrogenic mesenchyme cells achieve MET can be divided into several stages; induction, acquisition of stem cell character, fate determination, condensation, epitheliogenesis, polarisation and maturation. Progress through these stages is regulated by 'checkpoints' at which permission to proceed requires specific signals. The stages of development are characterised by the expression of new combinations of genes that code for transcription factors (Hox genes, Pax genes, zinc finger proteins), signalling effectors (growth factors, Wnts, receptor tyrosine kinases) and morphoregulatory molecules (CAMs, cadherins, extracellular matrix ligands). This review summarises current knowledge about the molecular interactions that control MET in the kidney, and also about how their failure might result in Wilms' tumour, one of the most common cancers of childhood.

Nucleotide sequence to a teicoplanin resistance gene from Actinoplanes teichomyceticus

A DNA fragment, isolated from A. teichomyceticus and able to confer teicoplanin resistance in a sensitive host, has been sequenced. It reveals the presence of two open reading frames (ORFs) positioned on opposite strands, named ORF1 and ORF2. ORF2 seems to be responsible for the acquisition of the resistance character.

Sex differences in the development of the motor activity circadian rhythm in rats under constant light

Differences between sexes in the maturation of the motor activity rhythm have been studied in rats (10 females and 7 males) born and raised under LL and isolated from the day of weaning. Motor activity data were registered every 30 minutes for 45 days after weaning. Periodogram analysis was applied to each animal data and the daily power spectra were calculated on the basis of the period, tau. The process of rhythm evolution was studied by means of an analysis of variance of a multivariant linear model, and by defining two mathematical functions that fit to the evolution of the total daily motor activity (TDMA) and the power content of the circadian harmonic (PCCH) through time: a sigmoidal function, which presents an inflexion point was used for the study of the evolution of the PCCH values through time; and a gaussian function, which presents a minimum was used for the evolution of the TDMA values. Results indicate that males show more ultradian components than females just after weaning, and take a longer time to acquire the circadian harmonic as the main harmonic in the daily power spectrum. The acquisition of the circadian character is preceeded by a decrease in the TDMA, in the case of the males and is followed by a decrease in TDMA in the case of the females. These results suggest sexual differences in the organization and maturation of the circadian system in rats.

Surface atomic geometry and electronic structure of II–VI cleavage faces

Recent models of the electronic structure and surface atomic geometries on wurtzite-structure CdS and CdSe have been extended to encompass zinc-blende structure CdTe. The driving force for the surface reconstruction of the cleavage faces of all these materials is the lowering in energy of a band of anion dangling bond surface states accompanied by their acquisition of back-bonding character. The resulting reconstructed surface is characterized by the eigenvalue spectrum associated with this band of states as well as the atomic geometries. The predicted geometries for CdTe(110), CdSe(101̄0), and CdSe(112̄0) are in good correspondence with low-energy electron diffraction (LEED) and low-energy positron diffraction intensity analyses. The calculated surface state eigenvalue spectra are compared with recent angle-resolved photoemission spectra (ARPES) for CdTe(110) and CdSe(101̄0). The main features of the ARPES measurements are reproduced by the calculated eigenvalue spectra. The predicted atomic geometry for CdTe(110) corresponds well both with prior predictions for ZnSe(110) and ZnS(110), and with LEED experimental surface structures indicating that these surfaces exhibit a universal structure in which the independent surface structural parameters scale linearly with the bulk lattice constant.

Transforming activity of human nasopharyngeal carcinoma DNA

NIH 3T3 cells were transfected with the DNAs from biopsy specimens of human nasopharyngeal carcinoma (NPC, EBV DNA positive) using calcium phosphate precipitation method. The malignant, transformed foci of NIH 3T3 cells have been observed and cloned. The hybridization of transfectant DNA digested by EcoRI with total human leukocyte DNA as probe was performed. The strong signal of smear comparing with NIH 3T3 DNA as control was observed. It was implied that the putative human transforming sequences had been integrated into transformed cells. Employing soft agar culture, the transformed cells can grow and form cell colonies. Following transfer, the foci were able to grow and adhere to a glass wall. These cells were easily agglutinated by con A. The cloned foci have been inoculated into nude mice with the formation of highly malignant sarcomas. In preliminary experiments for characterizing the transforming sequences, Ha-ras and Blym 1 were found in transfectants derived from one of the NPC DNA samples. It is implicated that these two oncogenes might be responsible for the acquisition of malignant phenotypic character of some human NPC. The further identification of oncogenes in NPC is currently in progress.

Sélection et analyse de mutants thermotolérants de Zymomonas mobilis, producteurs d'éthanol

Mutagenesis of Zymomonas mobilis ATCC 10988 induced by nitrosoguanidine and ethyl methanesulfonate leads to the acquisition of thermotolerant character. The nitrosoguanidine allows the obtention of the best mutants. At 38 °C, these mutant strains have growth kinetics and ethanol production rates similar to those of the wild-type strain grown at 30 °C. The mutants show delayed ethanol production when compared with Zymomonas mobilis ATCC 10988: this production occurs in part during the exponential growth phase and is still active at the beginning of the stationary phase.

Spermatozoal Ultrastructure in Branchiostoma moretonensis Kelly, a Comparison with B. lanceolatum (Cephalochordata) and with other Deuterostomes

The spermatozoon of Branchiostoma moretonensis closely resembles that of B. lanceolatum and, though near the primitive sperm, allows recognition of a cephalochordate sperm type. This has: a bell‐shaped acrosome; diffuse subacrosomal material not structured as an acrosome rod; sub‐ovoidal nucleus with shallow anterior concavity, deep tubular posterior fossa (endonuclear canal) and condensed but lacunate chromatin; single asymmetrical, postnuclear mitochondrion almost completely or completely encircling the centrioles; mutually perpendicular proximal and distal centrioles of the triplet type, with the distal forming the basal body of the flagellum and the proximal (always?), as in B. moretonensis, with a spur‐like extension (striated rootlet) into the nuclear fossa; flagellum tilted relative to the longitudinal axis (and endonuclear canal) of the nucleus; a 9 + 2 axoneme with hollow tubules and both dynein arms present on the doublets; and scattered glycogen granules, numerous around the distal centriole. The mitochondrion of B. moretonensis is C‐shaped in transverse section, as in urochordates, but cephalochordate sperm resemble those of echinoderms, and specifically holothuroids, more closely. The occurrence of flagellar rootlets and composite mitochondria in various animal groups is discussed. The term paramorphy is proposed for parallel and convergent acquisition of an identical character: symparamorphy where acquisition is by parallelism and alloparamorphy where it is by convergence; the two terms represent, however, extremes of a continuum. Superficially similar but structurally different characters acquired by convergence are termed analogomorphis.

ChemInform Abstract: A STABLE TRANS‐BENZAZONINYL ANION

The title substance (2) is formed on mild thermal treatment of the all-cis counterpart (1) with net relief of steric congestion and acquisition of aromatic character.

A stable trans-benzazoninyl anion

The title substance (2) is formed on mild thermal treatment of the all-cis counterpart (1) with net relief of steric congestion and acquisition of aromatic character.

Linkage Between Reproductive Capacity at Increased Temperature and Neurotropic Activity in A/NWS HONi (H 0 N 1 ) Influenza Virus

We investigated the rate of covariation between the ability of the NWS strain of influenza virus to reproduce at increased temperature and its neurotropic properties. Results indicated that increased growth at 39 C was related to increased neurovirulence, and acquisition of the temperature-sensitive character was related to loss of neurovirulence.

Fine structure of murine pulmonary adenocarcinomata induced by treatment with 20-methylcholanthrene in organ culture

Mouse lung tissue was treated with 20-methylcholanthrene in vitro and then implanted into host animals to await the appearance of tumours. The fine structure of pulmonary adenocarcinomata induced by this method was studied and found to resemble, in some respects, that of similarly induced adenomata and of mouse lung tumours arising spontaneously or induced in vivo. Ultrastructural differences between the adenocarcinomata and the previously described adenomata included increased irregularity of cell-surface membranes, disaggregation of ribosomes and decreased numbers of specific cytoplasmic lamellar inclusion bodies. These differences, as well as the greater variations in cell structure which were observed, appeared to be related to the acquisition of a malignant character by these tumours.