Clinical cone beam computed tomography compared to high-resolution peripheral computed tomography in the assessment of distal radius bone.

UNLABELLED: Clinical cone beam computed tomography (CBCT) was compared to high-resolution peripheral quantitative computed tomography (HR-pQCT) for the assessment of ex vivo radii. Strong correlations were found for geometry, volumetric density, and trabecular structure. Using CBCT, bone architecture assessment was feasible but compared to HR-pQCT, trabecular parameters were overestimated whereas cortical ones were underestimated. INTRODUCTION: HR-pQCT is the most widely used technique to assess bone microarchitecture in vivo. Yet, this technology has been only applicable at peripheral sites, in only few research centers. Clinical CBCT is more widely available but quantitative assessment of the bone structure is usually not performed. We aimed to compare the assessment of bone structure with CBCT (NewTom 5G, QR, Verona, Italy) and HR-pQCT (XtremeCT, Scanco Medical AG, Brüttisellen, Switzerland). METHODS: Twenty-four distal radius specimens were scanned with these two devices with a reconstructed voxel size of 75 µm for Newtom 5G and 82 µm for XtremeCT, respectively. A rescaling-registration scheme was used to define the common volume of interest. Cortical and trabecular compartments were separated using a semiautomated double contouring method. Density and microstructure were assessed with the HR-pQCT software on both modality images. RESULTS: Strong correlations were found for geometry parameters (r = 0.98-0.99), volumetric density (r = 0.91-0.99), and trabecular structure (r = 0.94-0.99), all p < 0.001. Correlations were lower for cortical microstructure (r = 0.80-0.89), p < 0.001. However, absolute differences were observed between modalities for all parameters, with an overestimation of the trabecular structure (trabecular number, 1.62 ± 0.37 vs. 1.47 ± 0.36 mm(-1)) and an underestimation of the cortical microstructure (cortical porosity, 3.3 ± 1.3 vs. 4.4 ± 1.4 %) assessed on CBCT images compared to HR-pQCT images. CONCLUSIONS: Clinical CBCT devices are able to analyze large portions of distal bones with good spatial resolution and limited irradiation. However, compared to dedicated HR-pQCT, the assessment of microarchitecture by NewTom 5G dental CBCT showed some discrepancies, for density measurements mainly. Further technical developments are required to reach optimal assessment of bone characteristics.

Use of whole cells of Pseudomonas aeruginosa for synthesis of the antioxidant hydroxytyrosol via conversion of tyrosol.

For the first time, a soil bacterium, designated Pseudomonas aeruginosa, was isolated based on its ability to grow on tyrosol as a sole source of carbon and energy. During growth on tyrosol, this strain was capable of promoting the formation of a significant amount of hydroxytyrosol and trace quantities of parahydroxyphenyl acetic acid and 3,4-dihydroxyphenyl acetic acid. The products were confirmed by high-performance liquid chromatography and gas chromatography-mass spectrometry analyses. Using an optimized tyrosol concentration of 2 g liter(-1), the maximal hydroxytyrosol yield (80%) was achieved after a 7-h reaction in a growth experiment. To enhance the formation of hydroxytyrosol and prevent its degradation, a resting-cell method using P. aeruginosa was performed. The growth state of the culture utilized for biomass production, the carbon source on which the biomass was grown, the concentration of the biomass, and the amount of tyrosol that was treated were optimized. The optimal yield of hydroxytyrosol (96%) was obtained after a 7-h reaction using 4 g of tyrosol liter(-1) and 5 g of cells liter(-1) pregrown on tyrosol and harvested at the end of the exponential phase. This proposed procedure is an alternative approach to obtain hydroxytyrosol in an environmentally friendly way. In addition, the reaction is easy to perform and can be adapted to a bioreactor for industrial purposes.

Protein size distribution and inhibitory effect of wheat hydrolysates on Neutrase.

Neutrase, used for hydrolysis of wheat proteins, was inhibited by end-product in a competitive uncompetitive way. The inhibition ratio depends on the progress of protein hydrolysis (degree of hydrolysis) and it remains constant beyond a degree of hydrolysis of 7.5%. The inhibitor was separated, on Sephadex G-25 column, in three fractions (>2.4, 2.4-0.5 and <0.5 kDa) generating an inhibition ratio of 29%, 46% and 67% respectively. The peptides size distribution (<1, 1-2, 2-3 and >3 kDa) of fractions was determined using size exclusion-high performance liquid chromatography. The analysis of obtained data, using a simple mathematical regression, showed a correlation factor of 0.98 between the inhibition ratio and the peptides less than 1 kDa and 0.99 when considering the peptides lower than 1 kDa and higher than 3 kDa.

Decolorization of olive mill waste-waters by free and immobilized Phanerochaete chrysosporium cultures. Effect of the high-molecular-weight polyphenols.

This paper describes the decolorization and chemical oxygen demand (COD) removal of olive mill waste-waters (OMW) by Phanerochaete chrysosporium grown in agitated submerged cultures. When P. chrysosporium was cultivated in the form of pellet, no decolorization of crude OMW was observed. Decolorization occurred only after removing by ultrafiltration, the high-mol-wt (HM) polyphenolic fraction (> 60 kDa). The use of high lignin peroxidase (LiP) producing medium yielded the highest levels of OMW decolorization and COD removal. In this case, extensive depolymerization and subsequent accumulation of phenolics with intermediates molecular weight were observed. Furthermore, increasing the concentration of the HM fraction decreased the color and COD removals. The decolorizing activity was lost when the concentration of the HM fraction reached 25% (v/v). Consequently, LiP activity was found to be completely inhibited in the presence of HM fraction, but not with the low-mol-wt (LM) polyphenolic fraction (< 8 kDa). The use of P. chrysosporium immobilized on polyurethane foam resulted in efficient decolorization of crude OMW. Moreover, the addition of an induction medium was shown to perform several repeated batch cultures for OMW decolorization and COD removal.

Roles of Lignin Peroxidase and Manganese Peroxidase from Phanerochaete chrysosporium in the Decolorization of Olive Mill Wastewaters.

The relative contributions of lignin peroxidase (LiP) and manganese peroxidase (MnP) to the decolorization of olive mill wastewaters (OMW) by Phanerochaete chrysosporium were investigated. A relatively low level (25%) of OMW decolorization was found with P. chrysosporium which was grown in a medium with a high Mn(II) concentration and in which a high level of MnP (0.65 (mu)M) was produced. In contrast, a high degree of OMW decolorization (more than 70%) was observed with P. chrysosporium which was grown in a medium with a low Mn(II) concentration but which resulted in a high level of LiP activity (0.3 (mu)M). In this culture medium, increasing the Mn(II) concentration resulted in decreased levels of OMW decolorization and LiP activity. Decolorization by reconstituted cultures of P. chrysosporium was found to be more enhanced by the addition of isolated LiP than by the addition of isolated MnP. The highest OMW decolorization levels were obtained at low initial chemical oxygen demands combined with high levels of extracellular LiP. These data, plus the positive effect of veratryl alcohol on OMW decolorization and LiP activity, indicate that culture conditions which yield high levels of LiP activity lead to high levels of OMW decolorization.

[Glucose isomerase of S. violaceoniger. Fundamental and applied aspects]. / Glucose isomerase de S. violaceoniger. Aspects fondamentaux et appliques.

XylA gene of Streptomyces violaceoniger (Drocourt et coll. 1988) code for a D-xylose isomerase activity which is used as a D-glucose isomerase activity in large scale. This gene is a part of regulated region involved in xylose utilization (Marcel et coll. 1987). Sequence determination of this region enabled us to characterize xylB gene (Xylulose kinase activity) and xylX gene which is involved in xylA and xylB expression. In order to construct a new strain having a strong and constitutive glucose isomerase activity, a newly isolated strong streptomyces promoter (P1 promoter), has been cloned behind xylA gene. To avoid instability of plasmid and glucose-isomerase activity, the P1-xylA gene of S. violaceoniger has been integrated into the chromosome, using the integrative vector pTS55. The resultant CBS1 strain has four to five fold higher glucose-isomerase activity in absence of xylose compared to that of strain SV1 fully induced by xylose. In addition, specific glucose-isomerase activity of CBS1 strain increases in the secondary growth phase, in contrast to wild type and SV1 strains.

Diet, living conditions and nasopharyngeal carcinoma in Tunisia--a case-control study.

We conducted a case-control study of nasopharyngeal carcinoma (NPC) in Tunisia, on diet, dietary patterns and life style, the characteristics of which had been defined by an anthropological study. Eighty incident cases, diagnosed in Tunisia between November 1986 and November 1987, were each matched for sex, age and place of residence to 2 controls. The subjects were asked for dietary data referring to the year preceding the diagnosis of NPC and, with help of their families, during childhood and after weaning. After adjustment for an empirical living conditions score, the following food items were found to be associated with an increased risk for NPC: preserved spiced meat (quaddid), basic stewing preparation (mixture of red and black pepper, garlic, oil, caraway and coriander), and harissa (red pepper, olive oil, garlic, caraway, salt) taken with bread as a snack during childhood and youth. Moreover, subjects who had been directly weaned from mother's milk on to an adult diet were found to be at higher risk for NPC.

Prognostic value of EBV markers in the clinical management of nasopharyngeal carcinoma (NPC): a multicenter follow-up study.

Between December 1979 and April 1982, 373 patients with untreated, undifferentiated carcinoma of the nasopharynx (NPC), 99 in Hong Kong, 120 in Tunis and 154 in Villejuif, entered a longitudinal study aimed at determining the clinical prognostic value of EBV serology after radiotherapy. A minimum of 3 years' follow-up was achieved for 319 patients (83 in Tunis, 95 in Hong Kong and 141 in Villejuif) who had regular clinical and serological testing at intervals of 6-8 months. No significant difference in initial serology (i.e., before any treatment) or variations of antibody titers at time of first follow-up was observed between patients who achieved complete remission after radiotherapy and those who did not. This included IgG and IgA antibodies to VCA, EA or EBNA. However, when patients with confirmed clinical remission 1 year after completion of radiotherapy were studied, the value of IgG/EA and mainly of IgA/EA increasing titers became highly significant for prediction of relapse, regardless of the initial titers. This demonstrated the clinical usefulness of EBV serology for NPC patients who have confirmed clinical remission after radiotherapy.

Presence of in vivo-activated T-cells expressing HLA-DR molecules and IL-2 receptors in peripheral blood of patients with nasopharyngeal carcinoma.

Epstein-Barr Virus (EBV) is associated with two malignant diseases, African Burkitt's Lymphoma (BL) and Undifferentiated Nasopharyngeal Carcinoma (UNPC). North Africa is a geographical area with a high incidence of NPC. Our purpose in this study was to explore cell-mediated immunity of peripheral blood lymphocytes (PBL) from patients with UNPC and DNPC. We found an elevated percentage of OKT8 cells and of large granular lymphocytes (LGL) (30-35% HNK-I-positive cells) compared to PBL from healthy matched individuals. PBL from NPC patients contained 35% HLA-DR-positive and 30% Interleukin-2 (IL-2) receptor-positive circulating lymphocytes. PBL from NPC patients exhibited a normal proliferative response to phytohemagglutinin (PHA) and Concanavalin A (Con A) and an increased response to pokeweed mitogen (PWM). Natural killer (NK) activity towards K562 cells was low in our patients who, in addition, exhibited no lytic activity against HLA-matched EBV-transformed B cells. This lack of cytotoxicity against an EBV-transformed B-cell line cannot be explained by an impairment of IL-2 secretion, and is probably a result of the presence of high numbers of OKT8 suppressor T cells.

Immunoglobulin allotypes in patients with nasopharyngeal carcinoma.

Gm phenotypes and the Km(1) allotype were studied in Tunisian patients with nasopharyngeal carcinoma (NPC). A highly significant association was found between the Km(1) allotype and the NPC disease. Two rare Gm haplotypes, Gm(1, 17; 11, 15, 21) and Gm(1, 3, 5, 11), were found to be significantly increased among the NPC patients.

Expression of HLA-DR antigens in nasopharyngeal carcinoma: an immunohistological analysis of the tumour cells and infiltrating lymphocytes.

A panel of conventional and monoclonal antibodies was used to examine the immunohistological characteristics of malignant epithelial cells and infiltrating lymphocytes in frozen sections of nasopharyngeal carcinoma (NPC) biopsies from 10 Tunisian patients. Three main categories of cells were identified. (1) Tumour cells which were positive for Epstein-Barr nuclear antigen, HLA-ABC and keratin determinants. In most samples, the tumour cells also expressed variable amounts of HLA-DR antigens. The presence of HLA-DR antigens has not been previously reported in NPC and may be a contributory factor in effecting the transfer of Epstein-Barr virus to the epithelial cells. (2) Infiltrating lymphocytes which were mainly composed of T inducer (T4+) and T suppressor/cytotoxic (T8+) cells although one sample contained predominantly immature T cells expressing the HTA-I+ cortical thymocyte phenotype. Few B cells or natural killer cells were demonstrated. (3) Large HTA-I+ dendritic cells which were invariably present within the tumour masses. These were morphologically and phenotypically similar to antigen presenting Langerhans cells which are usually located in the skin but also found in other epithelial sites. These cells may be a residual population from the normal nasopharynx or represent part of a specific immunological response to the presence of Epstein-Barr virus in the epithelial cells.