Influence of temperature and concentration on thermophysical properties of yellow mombin (Spondias mombin, L.)

Thermal conductivity, thermal diffusivity, and density of yellow mombin juice were determined at 8.8–49.4 °Brix and at temperature from 0.4 to 77.1 °C. Apparent viscosity was also measured between 7.8 and 30 °Brix and at temperature from 0 to 60 °C. Yellow mombin juice was produced from fruits of two different batches and the concentration process was performed using a roto evaporator or a rising film evaporator, single effect, with recirculation, under vacuum, to obtain concentrated juice. In order to obtain different concentrations, concentrated juice was diluted with distilled water. Multiple regression analysis was performed to fit thermal conductivity, thermal diffusivity and density experimental data obtaining a good fit. Arrhenius and power law relationships were proposed to fit apparent viscosity as a function of temperature and juice concentration at typical shear rates found during processing. The rheological parameters together with experimental values of pressure loss in tube flow were used to calculate friction factors, which were compared to those resulting from theoretical equation.     

VEGI, a novel cytokine of the tumor necrosis factor family, is an angiogenesis inhibitor that suppresses the growth of colon carcinomas in vivo

A novel member of the tumor necrosis factor (TNF) family has been identified from the human umbilical vein endothelial cell cDNA library, named vascular endothelial growth inhibitor (VEGI). The VEGI gene was mapped to human chromosome 9q32. The cDNA for VEGI encodes a protein of 174 amino acid residues with the characteristics of a type II transmembrane protein. Its amino acid sequence is 20-30% identical to other members of the TNF family. Unlike other members of the TNF family, VEGI is expressed predominantly in endothelial cells. Local production of a secreted form of VEGI via gene transfer caused complete suppression of the growth of MC-38 murine colon cancers in syngeneic C57BL/6 mice. Histological examination showed marked reduction of vascularization in MC-38 tumors that expressed soluble but not membrane-bound VEGI or were transfected with control vector. The conditioned media from soluble VEGI-expressing cells showed marked inhibitory effect on in vitro proliferation of adult bovine aortic endothelial cells. Our data suggest that VEGI is a novel angiogenesis inhibitor of the TNF family and functions in part by directly inhibiting endothelial cell proliferation. The results further suggest that VEGI maybe highly valuable toward angiogenesis-based cancer therapy.     

Development and evaluation of a novel pH indicator biodegradable film based on cassava starch

A pH indicator film based on cassava starch plasticized with sucrose and inverted sugar and incorporated with grape and spinach extracts as pH indicator sources (anthocyanin and chlorophyll) has been developed, and its packaging properties have been assessed. A second‐order central composite design (2²) with three central points and four star points was used to evaluate the mechanical properties (tensile strength, tensile strength at break, and elongation at break percentage), moisture barrier, and microstructure of the films, and its potential as a pH indicator packaging. The films were prepared by the casting technique and conditioned under controlled conditions (75% relative humidity and 23°C), at least 4 days before the analyses. The materials were exposed to different pH solutions (0, 2, 7, 10, and 14) and their color parameters (L*, a*, b*, and haze) were measured by transmittance. Grape and spinach extracts have affected the material characterization. Film properties (mechanical properties and moisture barrier) were strongly influenced by extract concentration presenting lower results than for the control. Films containing a higher concentration of grape extract presented a greater color change at different pH's suggesting that anthocyanins are more effective as pH indicators than chlorophyll or the mixture of both extracts. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Comparison of nipple projection with the modified double-opposing tab and star flaps

This study compared nipple projection after nipple reconstruction (following breast mound reconstruction) with either the modified double-opposing tab flap or the star flap. Areolar reconstruction and pigmentation of the nipple were achieved with tattooing. Nipple projection for 153 nipples was measured at least 6 months after the reconstruction, when projection was believed to have become stable. Mean follow-up was 2.27 years. In the 106 nipples reconstructed with modified double-opposing tab flaps, the mean projection was 2.4292 mm, while in the 47 nipples reconstructed with star flaps, the mean projection was 1.9681 mm (p = 0.021). We conclude that although both methods are effective, the modified double-opposing tab flap has slightly more projection after approximately 2 years. It is not known, however, whether this is because of reduced flap atrophy or longer initial projection by the modified double-opposing tab flap; further studies are ongoing.     

Modulation of the cleavage of glycosylphosphatidylinositol-anchored proteins by specific bacterial phospholipases

Many enzymes are tethered to the extracellular face of the plasma membrane by a glycosylphosphatidylinositol (GPI) anchor. These proteins can be released in soluble form by the action of GPI-specific phospholipase. Little is currently known about the factors modulating this release. We investigated the effects of several experimental variables on the cleavage of the GPI-anchored proteins 5'nucleotidase, acetylcholinesterase, and alkaline phosphatase by phospholipases from Bacillus thuringiensis and Staphylococcus aureus. Phospholipase activity was not inhibited by isotonic salt and was relatively unaffected by buffer type and concentration. In both cases, the optimum pH for cleavage was approximately 6.5. Over 80% of 5'-nucleotidase activity present in the lymphocyte plasma membrane was cleaved by the B. thuringiensis enzyme, and the initial rate of release was linear with phospholipase concentration. All three GPI-anchored proteins were released from lymphocyte plasma membrane at comparable phospholipase concentrations, suggesting that they have similar anchor structures. The catalytic activity of 5'-nucleotidase appeared to increase following conversion to the soluble form. The relative surface charge of the host plasma membrane modulated catalytic activity towards GPI-anchored proteins, depending on the net charge of the phospholipase. Studies on purified lymphocyte 5'-nucleotidase reconstituted into bilayers of dimyristoylphosphatidylcholine indicated that the efficiency of phospholipase cleavage was 12- to 50-fold lower when compared with the native plasma membrane. The ability of the phospholipase to cleave the GPI anchor was further reduced when the bilayer was in the gel phase.     

Increasing clinical pregnancy rates after IVF/ET. Can immunosuppression help?

OBJECTIVE: To evaluate the safety and efficacy of immunosuppression as an adjunct to improving the success of in vitro fertilization/embryo transfer (IVF-ET). STUDY DESIGN: A randomized, double-blind, placebo-controlled clinical trial. RESULTS: Seventy-five patients were randomized to receive either prednisone (39 patients, 51%) or placebo (36 patients, 49%). Patients in both groups had similar ages and numbers of preembryos transferred. CONCLUSION: Both the implantation and clinical pregnancy rates were higher in the prednisone group (16% vs. 11% and 43.5% vs. 32.3%, respectively). However, these differences did not achieve statistical significance. Evaluation of the ongoing pregnancy rate revealed little difference between the prednisone-treated patients (30.7%) and those receiving placebo (28.0%). There were no side effects reported by patients in either group.     

Color Doppler imaging and plasma levels of endothelin-1 in low-tension glaucoma

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by vascular endothelin cells There are reports in the literature that ET-1 plasma levels are raised in low tension glaucoma (LTG). ET-1 plasma concentration and Color Doppler Imaging (CDI) evaluation in ophthalmic and posterior ciliary arteries were measured in 15 LTG patients and in 15 healthy subjects. The blood flow index recorded for the ophthalmic artery in normal subjects was a PSV of 36.646 +/- 6.611 cm/sec with RI of 0.717 +/- 0.019 while in the LTG patients it was 32.961 +/- 3.045 cm/sec (p < 0.003) with RI of 0.789 +/- 0.018 (p < 0.001). For the posterior ciliary arteries in the same two groups, we obtained a PSV of 13.878 +/- 4.149 cm/sec vs 8.720 +/- 1.645 cm/sec (p < 0.001) and an RI of 0.679 +/- 0.039 vs 0.722 +/- 0.024 (p < 0.001). The plasma ET-1 level in normal subjects was 1.720 +/- 0.174 pg while in LTG patients it was 2.947 +/- 0.217 pg (p < 0.001). On the basis of our experience, we think that GON and the visual field damage found in LTG can be attributed to an alteration in the endothelial self-regulating sections and consequent vascular insufficiency, particularly pronounced in the posterior ciliary arteries which, since it is these that provide the blood supply to the optic nerve head, leads to irreversible functional damage.     

Variability in the stability of DNA-peptide nucleic acid (PNA) single-base mismatched duplexes: real-time hybridization during affinity electrophoresis in PNA-containing gels

The stability of all single-base mismatched pairs between a peptide nucleic acid 11-mer and its complementary DNA has been quantified in terms of their melting temperature and compared with the limited amount of data published to date. The strength of the interaction was determined by an automated affinity-electrophoretic approach permitting the visualization, in real time, of hybridization between a physically immobilized peptide nucleic acid and a complementary DNA migrating in an electric field. The dissociation constants are in the range of 10(-7) M (for mismatches) to 10(-10) M (for fully complementary DNA), which are in excellent agreement with solution studies. These and other thermodynamic constants can be accurately, rapidly, and reproducibly measured in this system at concentrations approaching dissociation conditions by using fluorescently labeled DNA in conjunction with commercial DNA sequencers. The stability of single-base mismatched peptide nucleic acid-DNA duplexes depends both on the position as well as on the chemical nature of the mismatch. The stability is at a minimum when the mutation is positioned 4 bases from either terminus (a loss of 20 degreesC or more in the melting temperature) but regains substantial stability when the mismatch is at the center of the duplex. The most stable mismatched pairs are G:T and T:T whereas destabilization is maximal for A:A and G:G. These observations are of significance in the design of probes for detecting mutations by hybridization.