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P Fuentealba

Publications and source records attributed to P Fuentealba.

8 recordsLinked to original sources
PubMed2003

Electron probability distribution in AIM and ELF basins.

The probabilities of finding a certain number of electrons enclosed in a given volume is calculated and discussed for a series of molecules. Two different methodologies to do the partition of the molecular space in separate volumes are investigated: the Atoms in the Molecules, AIM, topologic analysis of the density, and the topologic analysis of the Electron Localization Function (ELF). The formulas to calculate the probability distribution are reviewed and the way to implement them shortly explained. For a series of molecules, we present how the probability distribution complement the chemical information about the localization of the electrons in certain regions of the space. The calculations show that the probability of finding Z electrons in the AIM atomic basin associated to an atom of atomic number Z is, in general, low, even when the average number of electrons is close to Z. The probability distribution on the ELF basins associated to bonds yields new insight about the nature of the respective bond.

Journal Article↗
PubMed2000

Anatomical substrate for separate processing of ascending and descending visceral information in the nucleus of the solitary tract of the rat.

We examined the possible existence of divergent visceral pathways arising from the nucleus of the solitary tract, by co-injecting axonal tracers into the parabrachial nucleus and into the ventrolateral medulla. We found that around 5% of NTS neurons projected to both sites, and that neurons projecting to VLM were larger. This parallel organization allows a differential control of the ascending versus descending visceral pathways at an early stage of processing.

Animals↗
PubMed1997

DNA ploidy pattern and tumor suppressor gene p53 expression in gallbladder carcinoma.

The relationship between p53 gene expression and DNA content in advanced gallbladder carcinoma was studied. Fifty-three cases of advanced gallbladder carcinoma (45 primary tumors and 8 metastases) were analyzed, p53 protein expression was determined by immunohistochemistry, DNA content was measured by cytophotometric techniques. Study subjects included 45 (85%) female and 8 male patients, with an overall mean age of 58.6 years. Positive staining for p53 protein was observed in 27 (51%) cases. In subserosal tumors, the expression was significantly less than that in tumors that reached the serosa (P = 0.01). Twenty-nine (55%) cases were diploid and 24 were aneuploid. Sixty-seven % of primary tumors were diploid, whereas 87% of metastases showed an aneuploid DNA content. Both diploid and aneuploid tumors were positive for the p53 protein in the same proportion, and p53 was also expressed equally in both primary and secondary tumors. In advanced gallbladder carcinoma, the expression of the p53 gene was earlier than the accumulation of abnormal quantities of chromosomal DNA in the tumor cells. The determination of these events as markers in preneoplastic lesions is warranted in gallbladder carcinogenesis.

Adenocarcinoma↗
PubMed1997

[Determination of DNA content in salivary gland tumors].

BACKGROUND: DNA content determination is a useful tool in the characterization of different malignant tumors. AIM: To measure DNA content in cells of salivary gland tumors as adjunct to histological diagnosis, correlating morphologic and biological features of these tumors. MATERIAL AND METHODS: From the archives of the Pathology service of a general hospital, 21 salivary gland tumors, 15 pleomorphic adenomas, 3 mucoepidermoid carcinomas and 3 cystic adenoid carcinomas were selected. DNA content was determined in the histological samples using a flow cytometric DNA analysis. RESULTS: All pleomorphic adenomas had a normal or diploid DNA content. Fifty percent of malignant tumors had an aneuploid DNA content (1 mucoepidermoid carcinoma and 2 cystic adenoid carcinomas). CONCLUSIONS: DNA determination may help in the histological diagnosis of salivary gland tumors. The presence of aneuploidy suggests malignity.

Adenoma, Pleomorphic↗