Structural and chemical characterization of Yb2O3-ZrO2 system by HAADF-STEM and HRTEM

ZrO2:Yb3+ nanocrystalline phosphors with high concentrations of ytterbium ions were prepared using the sol-gel method. X-ray diffraction, high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy (HRTEM) were used to characterize the nanocrystalline phosphors annealed at 1000 degrees C. Unit-cell distortion and changes in the crystalline structure of the monoclinic zirconia to tetragonal zirconia, and subsequently cubic zirconia, were observed with increased Yb concentration. Yb ions were randomly distributed into the lattice of the crystalline structure. No segregation of Yb2O3 phase was observed. The substitution of Zr atoms by Yb atoms on different crystalline phases was confirmed by the experimental results and theoretical simulations of HRTEM and HAADF-STEM.

[Tooth loss in diabetic patients with and without chronic kidney disease and dialysis]

AIM

To compare tooth loss (TL) in ESRD (ESRD DM) and non-ESRD (DM) type 2 diabetic patients.

METHODS

Teeth loss was quantified, and dentition classified as: Non-Compromised (NCD) with > or = 25 teeth, partially compromised (PCD) with 9 to 24, and compromised (CD) with 0 to 8 teeth.

RESULTS

ESRD DM and DM: n> or = 103 and 130, mean age 57.9 and 58.5 yr (p> or =0.716), and at diabetes diagnosis 38.5 and 47.8 yr (p<0.001). Edentulous 23.5% and 13.8% (p> or =0.057), NCD 24.5% and 35.4% (p> or =0.074). TL was strongly associated mainly to periodontal disease (p<0.001). For ESRD DM, a low serum albumin (<3.5 g/dl) was more prevalent in peritoneal dialysis cases (p> or =0.0014), women (p> or =0.0100), people reporting unpleasant taste (UT) (p> or =0.0174), and those with a CD (p> or =0.0242).

CONCLUSIONS

There was a clear trend for more severe TL in ESRD DM cases, but no statistical difference was found. The association between low serum albumin, UT and CD imply a need for treatment of these conditions as a part of nutritional intervention in ESRD DM cases.

[Optimization of the pertussis vaccine production process]

The production of Pertussis Vaccine was reevaluated at the Instituto Nacional de Higiene "Rafael Rangel" in order to optimise it in terms of vaccine yield, potency, specific toxicity and efficiency (cost per doses). Four different processes, using two culture media (Cohen-Wheeler and Fermentación Glutamato Prolina-1) and two types of bioreactors (25 L Fermentador Caracas and a 450 L industrial fermentor) were compared. Runs were started from freeze-dried strains (134 or 509) and continued until the obtention of the maximal yield. It was found that the combination Fermentación Glutamato Prolina-1/industrial fermentor, shortened the process to 40 hours while consistently yielding a vaccine of higher potency (7.91 +/- 2.56 IU/human dose) and lower specific toxicity in a mice bioassay. In addition, the physical aspect of the preparation was rather homogeneous and free of dark aggregates. Most importantly, the biomass yield more than doubled those of the Fermentador Caracas using the two different media and that in the industrial fermentor with the Cohen-Wheeler medium. Therefore, the cost per doses was substantially decreased.

Oral findings in Mexican AIDS patients with cancer

Oral findings of 42 Mexican AIDS patients with cancer were reviewed. Kaposi's sarcoma (KS) was the most frequent malignancy (81%) followed by non-Hodgkin's lymphoma (NHL) (12%). All cases of NHL were of high or intermediate grade and most of them were extranodal. Out of the 34 individuals with KS, 22 (65%) showed oral KS and in 21 of them the palate was involved. The clinical features of oral KS including site, appearance and size are described. Pseudomembranous candidosis (PC), hairy leukoplakia (HL) and exfoliative cheilitis (ECh) were also found in these patients. There was no association of these lesions with any type of cancer. A strong association of oral candidosis and history of this infection was found, RR = 7.0 (1.3-4.1). There was evidence of severe immunosuppression in most patients, with mean average CD4 counts of 116 mm3 (range 4-841/mm3). Oral KS, ECh, PC and HL were more common in patients with lower CD4 counts. Our findings illustrate the most frequent oral lesions associated with HIV-1 infection in patients with AIDS and cancer, and further support the importance of oral examination in HIV infected patients.

[Oral pathology in 161 asymptomatic and symptomatic HIV-positive patients]

The aim of this study was to establish the prevalence of oral manifestations in HIV-infected patients and to correlate their frequency with the clinical stage. One hundred and sixty one HIV-positive individuals were examined, of whom 64 (40%) were in stages CDC-II and III and 97 (60%) in stage CDC-IV. The patients were examined at the AIDS out-patient clinic of the Instituto Nacional de la Nutrición Salvador Zubirán. The oral exams were performed by three examiners who were intra and inter calibrated, so that standard clinical criteria were followed. One hundred and twenty five patients (78%) showed one or more oral lesions. The proportion of patients with oral lesions increased significantly (p less than 0.05) according to the severity of the infection. Hairy leukoplakia (40%) and erythematous candidiasis (31%) were the most frequent lesions. When the prevalence of the different oral lesions was compared between the patients at early stages with the patients at the late stage no significant differences were found; only the pseudomembranous candidiasis and the exfoliative cheilitis were found with significantly higher values at stage CDC-IV than at earlier stages (p less than 0.001 and p less than 0.05 respectively). No association was found between oral candidiasis and tobacco use or xerostomia. Our study demonstrates that the prevalence and clinical features of the oral manifestations found showed similarities with those reported in other countries, but ulcero-necrotizing gingivitis was not found in our patients.

Oral lesions in Mexican HIV-infected patients

One hundred and twenty-five HIV-infected patients, of whom 49 (39%) were at early stages of the infection (CDC-II & III) and 76 (61%) in CDC IV, were prospectively examined. In 100 (80%) one or more oral mucosal lesions were observed; candidiasis (51%) and hairy leukoplakia (43%) were the commonest. Erythematous candidiasis was more often seen (35%) than the pseudomembranous type (16%), and appeared with the higher values at early than later stages. The prevalence of hairy leukoplakia, oral hyperpigmentation and xerostomia were incremented in groups CDC-IV. Pseudomembranous candidiasis and exfoliative cheilitis increased significantly with severity of disease. Our study demonstrates that oral alterations associated to HIV are a frequent finding, both at early (76%) and late (83%) stages of the infection in Mexican patients.