Non-uniform displacement and strain between the soleus and gastrocnemius subtendons of rat Achilles tendon.

Achilles tendon (AT) comprises of 3 subtendons arising from the soleus (SOL) and the lateral (LG) and medial (MG) heads of the gastrocnemius muscle. While recent human studies show differential displacement within AT, these displacements have not been attributed to specific subtendons. We tested the hypothesis that the SOL and LG subtendons show differential displacement and strain during various combinations of SOL, LG, and MG excitations. Movement of knots, sutured onto SOL and LG subtendons of 12 Wistar rats, was videotaped, while the muscles were stimulated intramuscularly and ankle torque was assessed. When SOL only was stimulated, the plantar flexion torque was the smallest among the different conditions (P < .001). In this condition, from passive to active state, the displacement (0.57 vs 0.47 mm, P = .002) and strain (8.4% vs 2.4%, P < .001) in the SOL subtendon were greater than in LG subtendon. When LG only was stimulated, a higher ankle torque was measured as compared to SOL stimulation (P < .001); the displacement was similar in both subtendons (~0.6 mm), while the strain was greater in LG than in SOL (4.7% vs 1.7%, P < .001). When all 3 muscles were stimulated simultaneously, ankle torque was highest and the displacement (0.79 vs 0.74 mm, P = .002) and strain (7.7% vs 4.4%, P = .003) were greater in SOL than in LG. These data show that the different subtendons of AT can experience relative displacement and differential strains. Together with anatomical dissections, the results revealed that such uniformities may be due to a lower stiffness of SOL subtendon compared to LG.

Altered mechanical interaction between rat plantar flexors due to changes in intermuscular connectivity.

Connective tissue formation following muscle injury and remedial surgery may involve changes in the stiffness and configuration of the connective tissues linking adjacent muscles. We investigated changes in mechanical interaction of muscles by implanting either a tissue-integrating mesh (n = 8) or an adhesion barrier (n = 8) to respectively increase or decrease the intermuscular connectivity between soleus muscle (SO) and the lateral gastrocnemius and plantaris complex (LG+PL) of the rat. As a measure of mechanical interaction, changes in SO tendon forces and proximal-distal LG+PL force differences in response to lengthening LG+PL proximally were assessed 1 and 2 weeks post-surgery. The extent of mechanical interaction was doubled 1 week post-implantation of the tissue-integrating mesh compared to an unaffected compartment (n = 8), and was more than four times higher 2 weeks post-surgery. This was found only for maximally activated muscles, but not when passive. Implanting the adhesion barrier did not result in a reduction of the mechanical interaction between these muscles. Our findings indicate that the ratio of force transmitted via myofascial, rather than myotendinous pathways, can increase substantially when the connectivity between muscles is enhanced. This improves our understanding of the consequences of connective tissue formation at the muscle boundary on skeletal muscle function.

Probiotic-enriched foods and dietary supplement containing SYNBIO positively affects bowel habits in healthy adults: an assessment using standard statistical analysis and Support Vector Machines.

A randomised, double-blind, placebo-controlled, parallel group study assessed in healthy adults how daily consumption of the probiotic combination SYNBIO®, administered in probiotic-enriched foods or in a dietary supplement, affected bowel habits. Primary and secondary outcomes gave the overall assessment of bowel well-being, while a Psychological General Well-Being Index compiled by participants estimated the health-related quality of life as well as the gastrointestinal tolerance determined with the Gastrointestinal Symptom Rating Scale. Support Vector Machine models for classification problems were used to validate the total outcomes on bowel well-being. SYNBIO® consumption improved bowel habits of volunteers consuming the probiotic foods or capsules, while the same effects were not registered in the control groups. The recovery of probiotic bacteria from the faeces of a cohort of 100 subjects for each supplemented group showed the persistence of strains in the gastrointestinal tract.

Grafting odorant binding proteins on diamond bio-MEMS.

Odorant binding proteins (OBPs) are small soluble proteins found in olfactory systems that are capable of binding several types of odorant molecules. Cantilevers based on polycrystalline diamond surfaces are very promising as chemical transducers. Here two methods were investigated for chemically grafting porcine OBPs on polycrystalline diamond surfaces for biosensor development. The first approach resulted in random orientation of the immobilized proteins over the surface. The second approach based on complexing a histidine-tag located on the protein with nickel allowed control of the proteins' orientation. Evidence confirming protein grafting was obtained using electrochemical impedance spectroscopy, fluorescence imaging and X-ray photoelectron spectroscopy. The chemical sensing performances of these OBP modified transducers were assessed. The second grafting method led to typically 20% more sensitive sensors, as a result of better access of ligands to the proteins active sites and also perhaps a better yield of protein immobilization. This new grafting method appears to be highly promising for further investigation of the ligand binding properties of OBPs in general and for the development of arrays of non-specific biosensors for artificial olfaction applications.

Percolation and three-dimensional structure of supercritical water.

It is well established that at ambient and supercooled conditions water can be described as a percolating network of H bonds. This work is aimed at identifying, by neutron diffraction experiments combined with computer simulations, a percolation line in supercritical water, where the extension of the H-bond network is in question. It is found that in real supercritical water liquidlike states are observed at or above the percolation threshold, while below this threshold gaslike water forms small, sheetlike configurations. Inspection of the three-dimensional arrangement of water molecules suggests that crossing of this percolation line is accompanied by a change of symmetry in the first neighboring shell of molecules from trigonal below the line to tetrahedral above.

Identification of melanoma with a gas sensor array.

BACKGROUND/PURPOSE: The relationship between diseases and alterations of the airborne chemicals emitted from the body has been found in many different pathologies and in particular for various forms of cancer. Metabolism of cancer cells is greatly altered during their lifetime; then, modification of chemicals is supposed to be large around cancer tissues. Positive hints in this direction were provided, as an example, on studying the breath composition of lung cancer-affected subjects. Besides the conventional analytical approaches, in recent years sensor arrays were also applied to these researches considering the chemical composition changes as those occurring in other applications such as for instance, those dealing with food quality measurements. METHODS: In this paper, the first application of sensor arrays to study the differentiation between melanomas and nevi, namely malignant and benign affection of melanocytary cells, respectively, is presented and discussed. The localization of lesions on the skin surface made possible the utilization of differential measurements aimed at capturing the differences between two adjacent skin regions. This approach strongly reduces the influence of skin headspace variability due to the peculiar subjective odour background and the skin odour variability. The measurement campaign involved 40 cases; 10 of these were diagnosed melanomas referred to surgical intervention. Nine of these diagnoses were further confirmed by histological examinations of the removed tissue and one was a false positive. RESULTS: The differences in the chemical composition of headspace were verified with a gas-chromatographic investigation, and the classification of electronic nose data provided an estimated cross-validated accuracy of the same order of magnitude as the currently used diagnostic instruments. CONCLUSION: Electronic nose sensors have been shown to have good sensitivity towards volatile organic compounds emitted by skin lesions, and the method seems to be effective for malign lesions identification. The results presented in this paper encourage a second experimental campaign with a larger number of participants and a systematic use of gas chromatography mass spectrometer technology in order to identify some possible melanoma biomarkers.

Determination of total and polycyclic aromatic hydrocarbons in aviation jet fuel.

The aviation jet fuel widely used in turbine engine aircraft is manufactured from straight-run kerosene. The combustion quality of jet fuel is largely related to the hydrocarbon composition of the fuel itself; paraffins have better burning properties than aromatic compounds, especially naphthalenes and light polycyclic aromatic hydrocarbons (PAHs), which are characterised as soot and smoke producers. For this reason the burning quality of fuel is generally measured as smoke fermation. This evaluation is carried out with UV spectrophotometric determination of total naphthalene hydrocarbons and a chromatographic analysis to determine the total aromatic compounds. These methods can be considered insufficient to evaluate the human health impact of these compounds due to their inability to measure trace (ppm) amounts of each aromatic hyrcarbon and each PAH in accordance with limitations imposed because of their toxicological properties. In this paper two analytical methods are presented. Both are based on a gas chromatographic technique with a mass detector operating in be selected ion monitoring mode. The first method was able to determine more than 60 aromatic hydrocarbons in a fuel sample in a 35-min chromatographic run, while the second was able to carry out the analysis of more than 30 PAHs in a 40-min chromatographic run. The linearity and sensitivity of the methods in measuring these analytes at trace levels are described.

Alginate microparticles for enzyme peroral administration.

In order to protect protein and peptide drugs against inactivation by different barriers in the gastro-intestinal tract and to improve their absorption, alginate microparticles as a carrier of L-lactate dehydrogenase, were developed by spray-drying technique. However, alginate complexation and spray-drying conditions led to enzyme activity loss. Such a drawback was overcome by using protectant additives (carboxymethylcellulose sodium salt, polyacrylic acid sodium salt, lactose) preventing the enzyme inactivation by both interaction with alginate and experimental conditions, lactose having the most protective effect. Nevertheless, only polyacrylic acid sodium salt provided a microparticulate structure required for the target of the Peyer's patches.

Protein immobilization in crosslinked alginate microparticles.

Oral administration of peptide and protein drugs requires their protection from the acidic and enzymatic degradation in the gastro-intestinal environment and their targeting to the absorption zone. For this purpose, an alginate microsystem, as a carrier of bovine serum albumin (BSA), as a model protein, was developed using a spray-drying technique. A hardening process with Ca2+ and chitosan (CS) provided a system with resistance to the gastro-intestinal barriers and of appropriate size for targeting to the Peyer's patches. The present work aims to evaluate the effects of the ratio of sodium alginate (Na-A) and BSA as well as the pH of the crosslinking medium on the microsystem properties. Microparticle morphological and dimensional characteristics did not change significantly with the formulation variables. BSA loading at a pH value less than the protein isoelectric point (pI) was higher than that at a pH similar to the pI owing to an electrostatic interaction between the charged protein and the polyanionic alginate. The maximum encapsulation efficiency was obtained at the highest Na-A/BSA ratio. Protein release in a simulated gastro-intestinal fluid was not affected by the preparative variables, but was controlled by the pH-dependent nature of the polymer material. Polyacrylamide gel electrophoresis (PAGE) demonstrated the stability of the protein to both the preparative conditions and the gastro-intestinal pH values.

Chitosan-alginate microparticles as a protein carrier.

The oral administration of peptidic drugs requires their protection from degradation in the gastric environment and the improvement of their absorption in the intestinal tract. For these requirements, a microsystem based on cross-linked alginate as the carrier of bovine serum albumin (BSA), used as a model protein, was proposed. A spray-drying technique was applied to BSA/sodium alginate solutions to obtain spherical particles having a mean diameter less than 10 microm. The microparticles were hardened using first a solution of calcium chloride and then a solution of chitosan (CS) to obtain stable microsystems. The cross-linking process was carried out at different CS concentrations and pH values of the cross-linking medium. The CS concentration affected the BSA loading in the microparticles prepared at a pH value less than the protein isoelectric point (pI). Moreover, the BSA loading at a pH value less than the pI was higher than that at a pH similar to the pI regardless of the CS concentration. This finding could be attributable to the formation of a BSA/alginate complex. The evaluation of the interaction between BSA and alginate at different pH values by means rheological measurements confirmed this hypothesis. This approach may represent a promising way to devise a microcarrier system with appropriate size for targeting the Peyer's patches, with appropriate immobilization capacity, and suitable for the oral administration of peptidic drugs.

Can kinetic analysis be a tool for evaluating pore characteristics?

As the pore morphology influences drug release, the purpose is to study pore characteristics by comparing bead performances. Casein/gelatin beads have been prepared by the emulsification extraction method, cross-linked with D,L-glyceraldehyde in acetone:water mixture 3:1 (v/v) and loaded with sodium fluorescein as a model drug. The beads with higher casein percentage have a higher matrix porosity, a wider average pore diameter and a higher cross-linking degree. The higher casein percentage causes a lower drug release rate. The kinetic analysis shows that the drug release occurs by diffusion and that the diffusion coefficient is affected by the casein percentage and the cross-linking degree. It can be hypothesized that the pore and channel morphology (tortuosity), due to the casein percentage in the matrix and the cross-linking treatment, can be evaluated by kinetic analysis of the release data.

PVP solid dispersions for the controlled release of furosemide from a floating multiple-unit system.

The poor bioavailability of orally dosed furosemide (FUR) is due to the presence of a biological window in the upper gastrointestinal tract. The purpose of the present study was to develop and optimize in vitro a multiple-unit floating system with increased gastric residence time for FUR. The incomplete release of FUR from the units, related to its low water solubility, led to the preparation and evaluation of different FUR samples to be incorporated into the units. The complete dose release over the actual intragastric residence time of the system (about 8 hr) was achieved by loading both the core and the membrane forming the units with a 1:5 FUR/polyvinylpyrrolidone (FUR/PVP) solid dispersion. Physicochemical analyses suggested the predominant role of the amorphous state of FUR in producing enhanced drug solubility and dissolution rate, which led to the desired release profile from the floating units.

Effect of matrix composition and process conditions on casein-gelatin beads floating properties.

Casein-gelatin beads have been prepared by emulsification extraction method and cross-linked with D,L-glyceraldehyde in an acetone-water mixture 3:1 (v/v). Casein emulsifying properties cause air bubble incorporation and the formation of large holes in the beads. The high porosity of the matrix influences the bead properties such as drug loading, drug release and floatation. These effects have been stressed by comparison with low porous beads, artificially prepared without cavities. The percentage of casein in the matrix increases the drug loading of both low and high porous matrices, although the loading of high porous matrices is lower than that of low porous matrices. As a matter of fact, the drug should be more easily removed during washing and recovery because of the higher superficial pore area of the beads. This can explain the drug release rate increase, observed in high porous matrix, in comparison with beads without cavities. This is due to the rapid diffusion of the drug through water filled pores. The study shows that cavities act as an air reservoir and enable beads to float. Therefore, casein seems to be a material suitable to the inexpensive formation of an air reservoir for floating systems.

Determination of phenolic antioxidants in aviation jet fuel.

The world-wide aviation jet fuel used for civil and military aircraft is of a kerosene type. To avoid peroxide production after the refinery process a specific antioxidant additive should be added on fuel. The antioxidants generally used are based on hindered phenols in a range of concentration 10-20 microg/ml. In the present work a specific method to measure the concentration of phenolic antioxidants is shown. The method is based on a liquid chromatographic technique with electrochemical detection. The technique, because of its selectivity, does not require sample pre-treatments. The analysis of a 5-10 ml fuel sample can be performed in less than 10 min with a sensitivity of 0.1 microg/ml and a RSD=2.5%. A comparison with another highly selective gas chromatographic technique with mass spectrometric detection with selected ion monitoring (GC-MS-SIM) is reported. The sensitivity of GC-MS-SIM method was 2 microg/ml with a RSD=3.1%.

Surface drug removal from ibuprofen-loaded PLA microspheres.

The preparation, characterisation and drug release behaviour of ibuprofen loaded poly(D,L-lactic acid) (PLA) microspheres are described. Depending on the gelatin concentration in the aqueous external solution (1, 0.5, 0.1% w/v), microspheres with three different sizes (2.2, 4.1, 7.5 micrometer) were obtained. The properties of microspheres washed with water (Untreated microspheres) (Un-Ms) were compared to those of the microspheres washed with a sodium carbonate solution in order to remove the surface drug (treated microspheres) (T-Ms). The results indicate that the removal of the surface drug did not induce any change in the size of the microspheres whereas the morphology of the smallest T-Ms appeared to be modified. The release profiles of both Un-Ms and T-Ms resulted in biphasic patterns. The initial burst effect (first release phase) of the T-Ms was lower than that of the Un-Ms. The rate of the second release phase did not change for the microspheres with the biggest size but increased for the smallest microspheres probably owing to the modification of the matrix porosity.

Casein/gelatin beads: I. Cross-linker solution composition effect on cross-linking degree.

The effect of the cross-linker solution composition (aqueous and organic ratio) on the cross-linking degree of hydrophilic casein/gelatin beads has been evaluated. Casein/gelatin beads with different radii have been prepared and treated over the same time with three different cross-linker solvent compositions containing d, l-glyceraldehyde at the same concentration. The cross-linking degree was studied not only comparing the results of swelling process and degradation rate, widely reported in literature as methods for the cross-linking degree evaluation, but also determining the solvent penetration rate and the d,l-glyceraldehyde reacting percentage. It has been observed, in fact, that the cross-linker solvent composition influences the penetration rate through the matrix of the cross-linker, thus controlling the homogeneity of the matrix cross-linking.

Surgical closure of muscular ventricular septal defects using double umbrella devices (intraoperative VSD device closure).

OBJECTIVES: Surgical closure of some muscular ventricular septal defects has been proven to be difficult. In order to simplify the surgical technique we have used intraoperatively Rashkind double umbrella devices to occlude muscular ventricular septal defects. METHODS: On the basis of haemodynamic and echocardiographic study five children aged 4, 6, 7, 14 and 41 months were considered suitable candidates for intraoperative closure of muscular ventricular septal defects (midmuscular in three cases, apical in two) by Rashkind devices. Three of them had previously undergone pulmonary artery banding at 10, 11 and 41 days, respectively. During hypothermic cardiopulmonary by pass a delivery system was introduced across the tricuspid valve into the right ventricle and then passed through the ventricular septal defect; the distal umbrella of a 17 mm device was opened in the left ventricular cavity; a traction was applied to the introducer and the proximal umbrella was opened on the right side straddling the interventricular septum; the device was then secured on the right side by few stitches. In one case because of the wide diameter of the ventricular septal defect two umbrellas were used. The surgical procedure was completed with debanding and/or closure of other defects close to the aortic or tricuspid valve. RESULTS: Immediate results, tested by epicardial or transesofageal echo, showed a minimal residual shunt in 4 patients and a moderate shunt in one. No early deaths occurred. A complete atrioventricular block developed in 1 patient who had an additional perimembranous defect closed with a prosthetic patch: a permanent pace maker was inserted 3 months after the operation. There was a late death for untractable right ventricular failure in 1 patient who had a large residual shunt erroneously considered moderate. In this patient, the size of the defect was underestimated both preoperatively then intraoperatively. The four survivors are doing well with no signs of hemodynamically significant residual shunts. CONCLUSIONS: The use of Rashkind umbrella devices for closing intraoperatively muscular defects can be helpful to standard surgical techniques when technical problems make patch closure difficult. Its use avoid the need of left ventriculotomy. Careful definition of the size of the defect is mandatory to select suitable candidates.

[Classification of congenital heart diseases and surgical interventions in pediatric cardiology for the standardization of hospitalization records]. / Classificazione delle cardiopatie congenite e degli interventi di cardiologia e cardiochirurgia pediatrica per una codifica standardizzata della documentazione di ricovero.

The utilization of DRGs for the evaluation of hospital activity requires the availability, on a current basis, of coded in-patient records (Hospital Discharge Form, SDO) with information concerning nosology of the patient and procedures performed. Consequently, the promotion of a standardized use of ICD.9 and ICD.9.CM code systems (International Classification of Diseases, 9th Revision, and International Classification of Diseases, 9th Revision, Clinical Modification) among clinicians is necessary. The National Research Council, Council Research Hospital for Cardiology and Cardiac Surgery (CREAS-IFC-CNR) has promoted the establishment of a permanent work group for the evaluation of the activity in the field of pediatric cardiology and cardiosurgery at a national level. In co-operation with two leading institution (AO "Bambino Gesù", Rome; AO "G. Gaslini", Genoa) an in-patient survey has been promoted including an overall revision of the ICD.9.CM code systems both for diagnosis and procedures in order to improve the standardization of data. Besides, the fitness of DRGs allocation by different codes has been judged. Some general and specific suggestions upon codes adequacy and DRGs identification have emerged from this study. The aim of this paper is to spread this preliminary standardization activity of the group as a contribution to the improvement of in-patient coded records quality.