Endoscopic Treatment for Vesicoureteral Reflux in Recurrent Urinary Tract Infections in Kidney Transplant: Experience of One Center.

Vesicoureteral reflux (VUR) after renal transplantation in adult patients has been reported. In renal transplant recipients, symptomatic urinary tract infection can cause high morbidity despite improved immunosuppressive and antibiotic treatment. In our country there have been few reported cases about use of copolymer of dextranomer and hyaluronic acid (DX-HA) injection in a renal transplant. We present 3 cases of recurrent or complicated infections with evidence of high-grade VUR, which were treated with DX-HA. Only 1 case had a partial remission; however, there were no episodes of urinary tract infection in 12 months of follow-up. Suburethral injection is an endoscopic treatment modality with low morbidity in our country.

Charge delocalization characteristics of regioregular high mobility polymers.

Controlling the regioregularity among the structural units of narrow bandgap conjugated polymer backbones has led to improvements in optoelectronic properties, for example in the mobilities observed in field effect transistor devices. To investigate how the regioregularity affects quantities relevant to hole transport, regioregular and regiorandom oligomers representative of polymeric structures were studied using density functional theory. Several structural and electronic characteristics of the oligomers were compared, including chain planarity, cation spin density, excess charges on molecular units and internal reorganizational energy. The main difference between the regioregular and regiorandom oligomers is found to be the conjugated backbone planarity, while the reorganizational energies calculated are quite similar across the molecular family. This work constitutes the first step on understanding the complex interplay of atomistic changes and an oligomer backbone structure toward modeling the charge transport properties.

Pendant ionic groups of conjugated oligoelectrolytes govern their ability to intercalate into microbial membranes.

Conjugated oligoelectrolytes (COEs) bearing pyridinium and carboxylate groups are synthesized, characterized, and compared to the trimethylammonium analogue from which they are derived. All COEs are able to spontaneously intercalate into liposomes, whereas only positively charged COEs intercalate into E. coli membranes. Membrane intercalation is determined necessary for performance enhancement in microbial fuel cells.

Role of average speed in N2O exhaust emissions as greenhouse gas in a huge urban zone (MVMZ): would we need a cold sun?

Nowadays, the drastic pollution problems, some of them related with greenhouse gas emissions, have promoted important attempts to face and diminish the global warming effects on the Mexico Valley Metropolitan Zone (MVMZ) as well as on the huge urban zones around the world. To reduce the exhaust gas emissions, many efforts have been carried out to reformulate fuels and design new catalytic converters; however, it is well known that other variables such as socio-economic and transport structure factors also play an important role around this problem. The present study analyzes the roles played by several commonly-used three-way catalytic converters (TWC) and the average traffic speed in the emission of N(2)O as greenhouse gas. According to this study, by increasing the average traffic flow and avoiding constant decelerations (frequent stops) during common trips, remarkable environmental and economic benefits could be obtained due to the diminution of N(2)O and other contaminant emissions such as ammonia (NH(3)) and even CO(2) with the concomitant reduced fossil fuel consumption. The actions mentioned above could be highly viable to diminish, in general, the global warming effects and contamination problems.

Reversible switching among three adsorbate configurations in a single [2.2]paracyclophane-based molecule.

Single 4,7,12,15-tetrakis(4'-dimethylaminostyryl)[2.2]paracyclophane molecules adsorb on NiAl(110) in different configurations. When the symmetry axes of the molecules are properly oriented with respect to the surface lattice, three adsorbate states of different conductance can be reversibly induced and directly imaged with a scanning tunneling microscope. Couplings between tunneling electrons and adsorbate vibrational and electronic states are primarily responsible for the transformation. However, change from low to high conductance configuration can also be triggered by electric field in the junction.

Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols.

High charge-separation efficiency combined with the reduced fabrication costs associated with solution processing and the potential for implementation on flexible substrates make 'plastic' solar cells a compelling option for tomorrow's photovoltaics. Attempts to control the donor/acceptor morphology in bulk heterojunction materials as required for achieving high power-conversion efficiency have, however, met with limited success. By incorporating a few volume per cent of alkanedithiols in the solution used to spin-cast films comprising a low-bandgap polymer and a fullerene derivative, the power-conversion efficiency of photovoltaic cells (air-mass 1.5 global conditions) is increased from 2.8% to 5.5% through altering the bulk heterojunction morphology. This discovery can potentially enable morphological control in bulk heterojunction materials where thermal annealing is either undesirable or ineffective.

Chemical imaging of single 4,7,12,15-tetrakis[2.2]paracyclophane by spatially resolved vibrational spectroscopy.

Single 4,7,12,15-tetrakis[2.2]paracyclophane were deposited on NiAl(110) surface at 11 K. Two adsorbed species with large and small conductivities were detected by the scanning tunneling microscope (STM). Their vibrational properties were investigated by inelastic electron tunneling spectroscopy (IETS) with the STM. Five vibrational modes were observed for the species with the larger conductivity. The spatially resolved vibrational images for the modes show striking differences, depending on the coupling of the vibrations localized on different functional groups within the molecule to the electronic states of the molecule. The vibrational modes are assigned on the basis of ab initio calculations. No IETS signal is resolved from the species with the small conductivity.

Glass-forming binaphthyl chromophores.

The use of the binaphthyl framework to synthesize glass-forming organic chromophores is described. Suzuki coupling reactions of racemic 6,6'-dibromo-2,2'-dialkoxy-1,1'-binaphthyl with 1,1-diphenyl-2-(4-dihydroxyboronphenyl)-ethene using [Pd(dppf)Cl2] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) as the catalyst provide a set of chromophores with the 4-(2,2'-diphenylvinyl)-1-phenyl group at the 6- and 6'-positions and a range of groups on the oxygen atom. Starting with enantiomerically enriched (R)-6,6'-dibromo-2,2'-dihexyloxy-1,1'-binaphthyl ((R)-2Hex), one can obtain (R)-3Hex. Heck coupling reactions of 6,6'-dibromo-2,2'-dialkoxy-1,1'-binaphthyl compounds with styrene provide chromophores of the type 2,2'-dialkoxy-1,1'-binaphthyl-6,6'-bis(2-phenyl-vinyl). Starting with enantiomerically enriched (R)-2Hex, one obtains (R)-4Hex. Molecules of the type 4 contain two 1-naphthyl-2-phenyl ethylene chromophores with a pseudoorthogonal relationship. Similar procedures can be used to obtain fragments with more extended conjugation length. Thus, the Heck coupling reaction of 2Hex with 4-(4'-tert-butylstyryl)styrene, 1-(4'-tert-butylstyryl)-4-(4'-vinylstyryl)benzene, and 1-(3',5'-dihexyloxystyryl)4-(4'-vinylstyryl)benzene provides 5Hex, 6Hex, and 7Hex, respectively. DSC measurements and powder diffraction experiments indicate that the binaphthol chromophores show a resistance to crystallization. In some cases, considerably different thermal behavior is observed between enantiomerically enriched samples and their racemic counterparts. Increasing the size of the conjugated fragment on the binaphthol core leads to materials with higher glass-transition temperatures and a less pronounced tendency to crystallize. Fluorescence spectroscopy gives evidence of "excimer"-type interactions in the solid state, except for the chromophores with 4-(2,2'-diphenylvinyl)-1-phenyl groups. It is possible to obtain amorphous films of these chromophores directly from solution, and to fabricate light-emitting diodes, in which the electroluminescent layer corresponds to the binaphthyl chromophore.

Bichromophoric paracyclophanes: models for interchromophore delocalization.

The electronic delocalization between chromophores in the solid is an important parameter to optimize when designing organic materials for optoelectronic applications. The [2.2]paracyclophane framework allows for the synthesis of well-defined, nonfluxional molecules that bring together two chromophores into close proximity. From the photophysical properties of these molecules we can examine how the chromophore conjugation length, their relative orientation, and the regiochemistry of contact affects the electronic delocalization between the two subunits.

[Molecular variants of human papillomavirus (HPV) types 16 and 18 in adenocarcinomas of the cervix]. / Variantes moleculares de virus papiloma humano (HPV) tipos 16 y 18 en adenocarcinomas de cérvix.

Human Papillomavirus (HPV), placebo clinical trial particularly types 16 and 18, are considered human carcinogens since an etiological association has been demonstrated between these viruses and the development of cervical cancer. While the viral role in squamous carcinoma has been largely studied, the information available on adenocarcinoma is scarce, partly because of its lower frequency. In this paper we investigated the presence of HPV types and intratype variants in adenocarcinomas of the cervix. A total of 23 archive samples, fixed and paraffin embedded biopsies, were included. The detection and viral typing was performed by generic PCR and subsequent single stranded conformational polymorphism analysis (SSCP). Genetic variability was investigated in a 450 bp-fragment corresponding to L1 gene by post-PCR direct sequencing. We detected 11 HPV 16 positive samples (9 prototypes and 2 variants: 1 European and 1 Asiatic-American), 10 HPV 18 (9 prototypes and 1 European variant), 1 HPV 31 and 1 negative. The high risk HPV association with this neoplasia was confirmed with a high prevalence (43%) of HPV 18, (but) without predominance over the other types as previously published. The demonstrated variability in L1 protein epitopes originated aminoacidic changes which could have implications on the immune response and therefore should be considered in a vaccine design.

[Ha-ras and p53 gene mutations scanned by PCR-SSCP in premalignant and malignant lesions of the uterine cervix associated with human papillomavirus]. / Mutaciones en genes Ha-ras y p53 detectadas mediante PCR-SSCP en lesiones premalignas y malignas de cuello uterino asociadas con virus papiloma humano.

The aim of this study w trial randomized as to investigate the frequencies of human papillomavirus (HPV) and mutation in Ha-ras oncogene and tumour suppressor p53 gene in cervical cancer and precursor lesions. A total of 30 invasive carcinomas (IC), 36 cervical intraepithelial neoplasia grade III (CIN III) and 12 normal tissues adjacent to the tumor (NT) were included. HPV typification and scanning of possible mutations in Ha-ras and p 53 genes were made by SSCP-PCR. The IC cases showed 93% HPV positivity, 41% having mobility shifts for Ha-ras mutations and 17% for p53 mutations while in CIN III, these percentages were 80%, 18% and 11%, respectively. In normal tissues HPV frequency was 17%. All Ha-ras mutated samples were HPV positive but 33% of p53 mutated cases were HPV negative. All mutations were heterozygous. HPV 16 was more prevalent (44%) than HPV 18 (15%) and the high rate of undetermined HPV types (18%) would indicate the circulation in our country of other types different from the assayed HPV controls (6, 11, 16, 18, 31 and 33), being variants or mixed infections. The low frequency of p53 mutations (17%) strengthens the view that wild type p53 inactivation by HPV probably plays a major role in the pathogenesis of cervical cancer. Because mutated Ha-ras was found in HPV associated premalignant lesions, we speculate that it represents an early marker for progression. Our findings provide additional evidence for an interactive effect between high risk types of HPV and oncogene activation in the development of uterine cervical cancer.

Variantes moleculares de virus papiloma humano (HPV) tipos 16 y 18 en adenocarcinomas de cérvix. / [Molecular variants of human papillomavirus (HPV) types 16 and 18 in adenocarcinomas of the cervix]

Human Papillomavirus (HPV), placebo clinical trial particularly types 16 and 18, are considered human carcinogens since an etiological association has been demonstrated between these viruses and the development of cervical cancer. While the viral role in squamous carcinoma has been largely studied, the information available on adenocarcinoma is scarce, partly because of its lower frequency. In this paper we investigated the presence of HPV types and intratype variants in adenocarcinomas of the cervix. A total of 23 archive samples, fixed and paraffin embedded biopsies, were included. The detection and viral typing was performed by generic PCR and subsequent single stranded conformational polymorphism analysis (SSCP). Genetic variability was investigated in a 450 bp-fragment corresponding to L1 gene by post-PCR direct sequencing. We detected 11 HPV 16 positive samples (9 prototypes and 2 variants: 1 European and 1 Asiatic-American), 10 HPV 18 (9 prototypes and 1 European variant), 1 HPV 31 and 1 negative. The high risk HPV association with this neoplasia was confirmed with a high prevalence (43

) of HPV 18, (but) without predominance over the other types as previously published. The demonstrated variability in L1 protein epitopes originated aminoacidic changes which could have implications on the immune response and therefore should be considered in a vaccine design.

Mutaciones en genes Ha-ras y p53 detectadas mediante PCR-SSCP en lesiones premalignas y malignas de cuello uterino asociadas con virus papiloma humano. / [Ha-ras and p53 gene mutations scanned by PCR-SSCP in premalignant and malignant lesions of the uterine cervix associated with human papillomavirus]

The aim of this study w trial randomized as to investigate the frequencies of human papillomavirus (HPV) and mutation in Ha-ras oncogene and tumour suppressor p53 gene in cervical cancer and precursor lesions. A total of 30 invasive carcinomas (IC), 36 cervical intraepithelial neoplasia grade III (CIN III) and 12 normal tissues adjacent to the tumor (NT) were included. HPV typification and scanning of possible mutations in Ha-ras and p 53 genes were made by SSCP-PCR. The IC cases showed 93

HPV positivity, 41

having mobility shifts for Ha-ras mutations and 17

for p53 mutations while in CIN III, these percentages were 80

, 18

and 11

, respectively. In normal tissues HPV frequency was 17

. All Ha-ras mutated samples were HPV positive but 33

of p53 mutated cases were HPV negative. All mutations were heterozygous. HPV 16 was more prevalent (44

) than HPV 18 (15

) and the high rate of undetermined HPV types (18

) would indicate the circulation in our country of other types different from the assayed HPV controls (6, 11, 16, 18, 31 and 33), being variants or mixed infections. The low frequency of p53 mutations (17

) strengthens the view that wild type p53 inactivation by HPV probably plays a major role in the pathogenesis of cervical cancer. Because mutated Ha-ras was found in HPV associated premalignant lesions, we speculate that it represents an early marker for progression. Our findings provide additional evidence for an interactive effect between high risk types of HPV and oncogene activation in the development of uterine cervical cancer.

Persistence of human papillomavirus DNA in cervical lesions after treatment with diathermic large loop excision.

OBJECTIVE: The aim of this study was to identify human papillomavirus (HPV) in cervical intraepithelial neoplasia (CIN) lesions and to evaluate the persistence of viral DNA after diathermic large loop excision (DLLE) treatment. STUDY DESIGN: Biopsies from 36 patients with low- and high-grade CIN lesions were studied before and after DLLE treatment looking for HPV sequences. DNA was extracted to perform a radioactive polymerase chain reaction (PCR) using GP 5,6 generic primers. PCR products were analyzed by the single-stranded conformational polymorphism (SSCP) which is a simultaneous detection and typing method. Dot-blot hybridization with generic and type-specific biotinylated oligonucleotide probes was applied in some cases. RESULTS: HPV DNA was found in all pretreatment samples, and the viral type was identified in 80% of them, HPV 16 being the most prevalent. The viral type coincided with that detected in the first biopsy in all except one case. Seventy five percent of the patients (27 cases) were negative for CIN at follow up, but 50% of them remained HPV DNA positive. CONCLUSION: DLLE treatment was effective in removing the CIN lesion but not the HPV. This fact points out the need to asses the presence of HPV in DNA during the follow-up, since viral persistence has been considered a high risk factor for recurrence and/or malignant transformation.

Nucleosynthesis in stars: recent developments.

The development of new observational, experimental, and computational technologies is changing our understanding of the origins of the elements by thermonuclear burning in stars. Gamma-ray lines from newly made radioactive nuclei have been identified using instruments onboard low-Earth orbiting satellites. Grains in meteorites have isotopic anomalies which suggest that the grains were put together in a stellar explosion such as a supernova. Computer simulations allow such anomalies to be used to probe how these events happen. The simulations are being independently tested by experiments with high-energy density lasers. These developments are beginning to provide a quantitative diagnostic of galactic evolution, and of the epoch of formation of the first stars and galaxies.