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Natural silk fibers show valuable changes in elastic modulus, E, and failure stress, σf, upon treatment with an air flux of gaseous Si-alkoxides bearing a thin sol-gel layer of SiO2 on the fiber surface. These mechanical features are studied here as a function of the composition of gaseous flux and reaction time. Owing to the different behavior between original and treated fibers submitted to loading-unloading cycles, the maximum increase in E (about 50%) and σf (about 30%) are discussed in terms of intermolecular surface interactions of -O-Si-O- bridging groups and protein macromolecules. As an extension of this system, composed of a thin sol-gel SiO2 layer (0.05–0.1 μm) on protein surfaces, the mechanical improvement of collagen + cell deposits upon deposition of sol-gel SiO2 is suggested. [ABSTRACT FROM AUTHOR]

Pancreatic rat islets are encapsulated by a siliceous layer deposited on the surface of single islets upon reaction with gaseous siliceous precursors. The process preserves original islet dimensions and does not suppress viability or function. The encapsulated material is homogeneously distributed on the islet surface, and layer thickness can be controlled in the 0.1–2.0 μm interval. Dynamic perfusion experiments with glucose stimulation were carried out in both encapsulated and non-encapsulated islets. Results were treated according to a kinetic model presented here for the analysis of perfusion data; the model tested by literature data, was used to substantiate the diffusion features of the siliceous layer, which does not affect mass transfer of insulin but which modifies the texture of the islet surface tissue. The clinical potential of silica encapsulation was demonstrated by in vivo experiments using encapsulated islets transplanted into diabetic rats. Transplantation was carried out in both inbred and outbred rats and indicated prolonged restoration of normal glycaemia levels and protection from immunological attack. [Copyright &y& Elsevier]

Plant cell cultures have emerged as a promising tool for producing active molecules due to their numerous advantages over traditional agricultural methods. Flavonols, and anthocyanin pigments in particular, together with other phenolic compounds such as chlorogenic acid, are known for their beneficial health properties, mainly due to their antioxidant, antimicrobial, and anti-inflammatory activities. The synthesis of these molecules is finely regulated in plant cells and controlled at the transcriptional level by specific MYB and bHLH transcription factors that coordinate the transcription of structural biosynthetic genes. The co-expression of peach PpMYB10.1 and PpbHLH3 in tobacco was used to develop tobacco cell lines showing high expression of both the peach transgenes and the native flavonol structural genes. These cell lines were further selected for fast growth. High production levels of chlorogenic acid, anthocyanins (mainly cyanidin 3-rutinoside), and other phenolics were also achieved in pre-industrial scale-up trials. A single-column-based purification protocol was developed to produce a lyophile called ANT-CA, which was stable over time, showed beneficial effects on cell viability, and had antioxidant, anti-inflammatory, antibacterial, and wound-healing activities. This lyophile could be a valuable ingredient for food or cosmetic applications.

Rat hepatocytes in a collagen-gel sandwich configuration were exposed to silicon alkoxides in a gas phase, yielding a 0.05 to 0.15 microm porous silica layer on the gel surface. Cell viability was unaffected by the procedure. After 24 h, bilirubin conjugation, ammonia removal, urea synthesis, and diazepam metabolism were unaffected by the procedure. However, both the ammonia removal rate and diazepam metabolism were increased after 48 hr, whereas urea synthesis was unaffected. These data indicate that silica overlay allows efficient metabolic activity of collagen-gel entrapped hepatocytes. The fact that the KM of bilirubin conjugation was unaffected by the presence of the silica membrane suggests that the transport of albumin-bound substrates is not decreased. The enhancement in some metabolic activities found 48 h after the entrapment procedure may be the result of favorable changes in the hepatocyte microenvironment. These characteristics might be useful for the development of organotypical bioartificial liver devices.

Aim of the Study: In the recent literature it has been emerged the importance of grading and staging of chronic viral hepatitis. Numerous different methods of grading and staging have been proposed. Purpose of the present paper was to compare the methods proposed by Knodell et al., Scheuer, and Ishak et al., Materials and Methods: Forty consecutive cases of chronic viral hepatitis constituted the basis of the study. Each case was graded as mild, moderate and severe activity and staged according to the criteria described in the three methods. In particular portal-periportal activity, lobular activity and fibrosis were evaluated. The final evaluation of the liver biopsy, together with the result of each single feature, were then compared., Results: The three different methods gave grossly similar results in the overall grading of the cases. Analyzing the single features, differences were noted in the evaluation of the lobular activity. This is probably the consequence of the different qualitative and quantitative criteria applied. Comparison of the data obtained by evaluating the extension of fibrosis was quite difficult, owing to the extremely different scales of grading used in each single method., Conclusions: In this study three different methods of grading and staging of chronic viral hepatitis were compared. The final evaluations of the cases obtained with the different methods were almost superimposable. Comparing the data obtained with long term follow-up of the patients may better clarify which of the different methods can have a prognostic value.

The presence and distribution of hepatitis B core antigen (HBcAg) was studied in the liver of 227 chronic carriers of hepatitis B surface antigen (HBsAg) to investigate its relationship with serum HBV-DNA, the status of hepatitis B 'e' antigen/antibody (HBeAg/anti-HBe) and the underlying liver disease. HBcAg was detected in 144 of the 227 (63%) liver specimens and HBV-DNA in 132 (58%) of the corresponding sera. Serum HBV-DNA showed a constant link with intrahepatic HBcAg. Out of 96 HBeAg-positive patients, 91 (95%) had HBcAg in the liver and 85 (89%) had HBV-DNA in serum. Overall there was a significant link between HBeAg and HBV-DNA in serum, but there was no correlation in 58 out of 227 (26%) cases. In HBeAg/HBV-DNA-positive carriers, HBcAg expression was predominantly nuclear. It was nuclear and cytoplasmic in patients with the highest levels of viremia. Eleven out of 13 (85%) HBV-DNA-positive patients who had only cytoplasmic HBcAg were HBcAg-negative and had low levels of HBV-DNA. Nine of 13 (69%) patients with exclusively cytoplasmic HBcAg had severe chronic liver disease. Neither the presence of HBV-DNA and HBeAg in serum nor the nuclear localization of HBcAg were associated with the severity of liver damage. In the group of HBV-DNA-positive patients (132), the presence of liver disease was significantly connected with the absence of HBeAg in serum (P less than 0.05; C.L. 3-35).(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of this study was to gain experience concerning efficacy and safety of famotidine, the new H2-receptor antagonist, for the maintenance of duodenal ulcer disease. 344 patients whose acute duodenal ulceration had recently been healed under famotidine or ranitidine were recruited for a year maintenance treatment with 20 mg bedtime dose of famotidine or placebo. 167 patients were treated with famotidine over 6 and 52 over 12 months. The corresponding numbers in the placebo control were 177 and 21. A life table method of analyses showed that the ulcer relapse rate was consistently and significantly (p less than 0.01) lower on famotidine than on placebo after 6 months (26% [43/167] versus 55% [98/177]). Of the 52 patients treated with 20 mg famotidine at night for further 6 months 7 (14%) developed an ulcer relapse. Of the 21 patients treated for further 6 months with placebo 5 (24%) showed an acute ulcer crater at endoscopy. Famotidine was well tolerated in the longterm therapy. The results confirm the efficacy and safety of famotidine in the prevention of duodenal ulcer relapse for at least 6 months.