Starch gelatinization and in vitro digestibility behaviour after heat treatment: Comparison between plantain paste and piece of pulp.

Over the 65-100°C range and at a water content of 1.6kgkg(-1)db, a comparison was conducted between plantain paste (dispersion made of flour and water) and pulp pieces after cooking to evaluate their respective degree of starch gelatinization (α) and in vitro digestibility. Below 76°C and at 100°C, the gelatinization behaviour of starch into pulp pieces and paste was similar, whereas at 85°C a significant mean relative difference was observed in between. For α in the 0-1 range, pieces of plantain pulp exhibited a lower rapidly digestible starch fraction (30%) and a higher resistant starch fraction (33%) than the flour paste, suggesting some structural effects. Both Weibull and exponential models showed a good fit for α over temperature range and starch digestibility fractions over α. Although no explicit relationship was established between the intact pulp structure and grinded flour state of plantain, the evaluation of the degree of starch gelatinization and digestibility of a plantain flour paste, could be used to predict the gelatinization and digestibility behaviour of plantain starch in entire pieces of pulp.

Hyperthermic intraperitoneal chemotherapy leads to an anticancer immune response via exposure of cell surface heat shock protein 90.

The occurrence of peritoneal carcinomatosis is a major cause of treatment failure in colorectal cancer and is considered incurable. However, new therapeutic approaches have been proposed, including cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Although HIPEC has been effective in selected patients, it is not known how HIPEC prolongs a patient's lifespan. Here, we have demonstrated that HIPEC-treated tumor cells induce the activation of tumor-specific T cells and lead to vaccination against tumor cells in mice. We have established that this effect results from the HIPEC-mediated exposure of heat shock protein (HSP) 90 at the plasma membrane. Inhibition or blocking of HSP90, but not HSP70, prevented the HIPEC-mediated antitumoral vaccination. Our work raises the possibility that the HIPEC procedure not only kills tumor cells but also induces an efficient anticancer immune response, therefore opening new opportunities for cancer treatment.

Effect of fragarin on the cytoplasmic membrane of the phytopathogen Clavibacter michiganensis.

Fragarin, an antibiotic that was isolated and purified from a soluble fraction of strawberry leaves, may be a new type of preformed antimicrobial compound (phytoanticipin). Here, we report that the growth and oxygen consumption of the phytopathogenic bacterium Clavibacter michiganensis were rapidly inhibited after the addition of fragarin to cultures. Also, dissipation of the membrane potential and an increase of cell membrane permeability were observed in the presence of fragarin. The ability of fragarin to dissipate the membrane potential was confirmed with the use of small unilamellar liposomes made with lipids extracted from C. michiganensis. Our results suggest that fragarin is able to act at the membrane level, and that this action is correlated with a decrease in cell viability.

Protein denaturation induced by cyclic silicone.

While it has been demonstrated that such low-molecular-weight cyclic silicones as octamethylcyclotetrasiloxane (D4) exhibit adjuvant activity, the mechanism of immunological response to silicone is still not clear. This study therefore used fluorescence and circular dichroism (CD) spectroscopy to investigate the denaturation and conformational change of two proteins, fibronectin (Fn) and fibrinogen (Fbg), induced by D4 in vitro. Incubating D4 with Fbg or Fn at D4-to-protein ratios of > 100 or for > 10 h yielded white and mould-like precipitates of the proteins, indicating massive denaturation and aggregation. The fact that the decrease in fluorescence intensity of D4-treated Fn and Fbg was accompanied by a red shift in the maximum wavelength also indicated that denaturation of the proteins had taken place. These changes in fluorescence might result from exposure of tryptophan residuals in the proteins to polar water molecules inasmuch as the denaturation would lead to changes in the tertiary structures of the proteins and rearrangement of the tryptophan residues. The loss of the tertiary structure leads to protein denaturation and, consequently, precipitation. The difference in CD spectra between control Fbg (or Fn) and D4-treated Fbg (or Fn) indicated conformational changes of the proteins when incubated with D4. Thus it has been demonstrated that D4 can induce denaturation and conformational changes in Fbg and Fn and it can be expected that protein molecules that have undergone denaturation or conformational change induced by D4 may act as antigens and stimulate the immune system to generate antibodies, ultimately resulting in autoimmune disease.

Analysis of osteoblast mineral deposits on orthopaedic/dental implant metals.

Neonatal rat calvarial osteoblasts were cultured on Ti-6Al-4V, Co-Cr-Mo alloy, 316L stainless steel and polystyrene (reference substrate) in the presence of ascorbic acid and 10 mM beta-glycerophosphate for 16, 17, 18, 19, 20, 21, 24 and 28 d. Scanning electron microscopy examination revealed that osteoblasts cultured on these orthopaedic/dental implant metals synthesized and deposited an extracellular matrix containing collagenous and non-collagenous components, as well as mineral nodules of various morphologies. Energy dispersive spectrometry revealed that the mineral deposits consisted of three distinct chemical compositions: calcium phosphate, calcium-sulphur-phosphorus, and calcium only. Backscattered electron imaging demonstrated that both the calcium phosphate and calcium-only deposits were electron dense, while the calcium-sulphur-phosphorus deposits were electron translucent. X-ray diffraction analysis indicated that the bulk of the osteoblast mineral deposits was amorphous hydroxyapatite; in addition, electron diffraction analysis revealed small regions of crystalline hydroxyapatite.

Trends in use of barium enema examination, colonoscopy, and sigmoidoscopy: is use commensurate with risk of disease?

PURPOSE: To assess replacement of barium enema examination with colonoscopy in relation to age- and sex-related risk factors, place of service, physician specialty, and cost. MATERIALS AND METHODS: Between 1985 and 1992, 894,777 insurance claims for barium enema examination and lower gastrointestinal endoscopy were retrospectively examined. Changes in use were investigated. Use of proctosigmoidoscopy and flexible sigmoidoscopy, two office-based endoscopic procedures, was also examined. RESULTS: Use of diagnostic colonoscopy increased from 191 to 406 services per 100,000 persons; colonoscopy with biopsy, from 77 to 183 services; and colonoscopy with lesion removal, from 77 to 202 services. Barium enema examination use declined from 929 to 511 services per 100,000 persons; diagnostic proctosigmoidoscopy, from 854 to 193 services; and diagnostic flexible sigmoidoscopy, from 656 to 620 services. Increases in use of colonoscopy in patients aged younger than 40 years were greater than overall increases. CONCLUSION: Colonoscopy has been replacing barium enema examination as the initial colorectal examination since 1985. Increased use of colonoscopy in patients with lower risk of neoplasia suggests that indications have become overly broad.