Can dynamic in vitro digestion systems mimic the physiological reality?

During the last decade, there has been a growing interest in understanding the fate of food during digestion in the gastrointestinal tract in order to strengthen the possible effects of food on human health. Ideally, food digestion should be studied in vivo on humans but this is not always ethically and financially possible. Therefore simple static in vitro digestion models mimicking the gastrointestinal tract have been proposed as alternatives to in vivo experiments but these models are quite basic and hardly recreate the complexity of the digestive tract. In contrast, dynamic models that allow pH regulation, flow of the food and injection in real time of digestive enzymes in the different compartments of the gastrointestinal tract are more promising to accurately mimic the digestive process. Most of the systems developed so far have been compared for their performances to in vivo data obtained on animals and/or humans. The objective of this article is to review the validation towards in vivo data of some of the dynamic digestion systems currently available in order to determine what aspects of food digestion they are able to mimic. Eight dynamic digestion systems are presented as well as their validation towards in vivo data. Advantages and limits of each simulator is discussed. This is the result of a cooperative international effort made by some of the scientists involved in Infogest, an international network on food digestion.

Antibacterial activity of wine phenolic compounds and oenological extracts against potential respiratory pathogens.

AIMS: To investigate the effect of seven wine phenolic compounds and six oenological phenolic extracts on the growth of pathogenic bacteria associated with respiratory diseases (Pseudomonas aeruginosa, Staphylococcus aureus, Moraxella catarrhalis, Enterococcus faecalis, Streptococcus sp Group F, Streptococcus agalactiae and Streptococcus pneumoniae). METHODS AND RESULTS: Antimicrobial activity was determined using a microdilution method and quantified as IC(50) . Mor. catarrhalis was the most susceptible specie to phenolic compounds and extracts. Gallic acid and ethyl gallate were the compounds that showed the greatest antimicrobial activity. Regarding phenolic extracts, GSE (grape seed extract) and GSE-O (oligomeric-rich fraction from GSE) were the ones that displayed the strongest antimicrobial effects. CONCLUSIONS: Results highlight the antimicrobial properties of wine phenolic compounds and oenological extracts against potential respiratory pathogens. The antimicrobial activity of wine phenolic compounds was influenced by the type of phenolic compounds. Gram-negative bacteria were more susceptible than Gram-positive bacteria to the action of phenolic compounds and extracts; however, the effect was species-dependent. SIGNIFICANCE AND IMPACT OF STUDY: The ability to inhibit the growth of respiratory pathogenic bacteria as shown by several wine phenolic compounds and oenological extracts warrants further investigations to explore the use of grape and wine preparations in oral hygiene.

Degradation of biogenic amines by vineyard ecosystem fungi. Potential use in winemaking.

AIMS: To evaluate the ability of grapevine ecosystem fungi to degrade histamine, tyramine and putrescine in synthetic medium and in wines. METHODS AND RESULTS: Grapevine and vineyard soil fungi were isolated from four locations of Spain and were subsequently identified by PCR. A total of 44 fungi were evaluated for in vitro amine degradation in a microfermentation system. Amine degradation by fungi was assayed by reversed-phase (RP)-HPLC. All fungi were able to degrade at least two different primary amines. Species of Pencillium citrinum, Alternaria sp., Phoma sp., Ulocladium chartarum and Epicoccum nigrum were found to exhibit the highest capacity for amine degradation. In a second experiment, cell-free supernatants of P. citrinum CIAL-274,760 (CECT 20782) grown in yeast carbon base with histamine, tyramine or putrescine, were tested for their ability to degrade amines in three different wines (red, white and synthetic). The highest levels of biogenic amine degradation were obtained with histamine-induced enzymatic extract. CONCLUSION: The study highlighted the ability of grapevine ecosystem fungi to degrade biogenic amines and their potential application for biogenic amines removal in wine. SIGNIFICANCE AND IMPACT OF STUDY: The fungi extracts described in this study may be useful in winemaking to reduce the biogenic amines content of wines, thereby preventing the possible adverse effects on health in sensitive individuals and the trade and export of wine.

Feasibility and application of liquid-liquid extraction combined with gas chromatography-mass spectrometry for the analysis of phenolic acids from grape polyphenols degraded by human faecal microbiota.

In this study the feasibility of a LLE-GC-EI-MS method for the analysis of 43 phenolic acids belonging to different chemical structure families which have been described in the literature as microbial-derived metabolites after consumption of dietary polyphenols was proved. In addition, the method was applied for the characterisation of phenolic metabolites resulting from the incubation, in anaerobic conditions, of a commercial grape seed extract (GSE) and their corresponding flavan-3-ol monomeric (GSE-M) and oligomeric (GSE-O) fractions with human faeces from healthy volunteers (n=3). The method showed average values of repeatability and reproducibility of 5.0% and 6.3%, respectively, adequate and low detection (1.8-30.8 µg L(-1)) and quantification limits (6.0-102.8 µg L(-1)) and good recovery values (95%, as average value). A total of 27 phenolic acids were identified in the faecal solutions after incubation with the grape seed extracts. In general, faecal samples incubated with GSE and GSE-M (monomeric fraction) yield a higher formation of phenolic acids compared to the samples incubated with the oligomer fraction (GSE-O).

Inactivation of oenological lactic acid bacteria (Lactobacillus hilgardii and Pediococcus pentosaceus) by wine phenolic compounds.

AIMS: To investigate the inactivation properties of different classes of phenolic compounds present in wine against two wine isolates of Lactobacillus hilgardii and Pediococcus pentosaceus, and to explore their inactivation mechanism. METHODS AND RESULTS: After a first screening of the inactivation potency of 21 phenolic compounds (hydroxybenzoic and hydroxycinnamic acids, phenolic alcohols, stilbenes, flavan-3-ols and flavonols) at specific concentrations, the survival parameters (MIC and MBC) of the most active compounds were determined. For the L. hilgardii strain, the flavonols morin and kaempferol showed the strongest inactivation (MIC values of one and 5 mg l(-1), and MBC values of 7.5 and 50 mg l(-1), respectively). For the P. pentosaceus strain, flavonols also showed the strongest inactivation effects, with MIC values between one and 10 mg l(-1) and MBC values between 7.5 and 300 mg l(-1). Observations by epifluorescence and scanning electron microscopy revealed that the phenolics damaged the cell membrane and promoted the subsequent release of the cytoplasm material into the medium. CONCLUSIONS: The antibacterial activity of wine phenolics against L. hilgardii and P. pentosaceus was dependent on the phenolic compound tested, and led not only to bacteria inactivation, but also to the cell death. SIGNIFICANCE AND IMPACT OF THE STUDY: New information about the inactivation properties of wine lactic acid bacteria by phenolic compounds is presented. It opens up a new area of study for selecting/obtaining wine phenolic preparations with potential applications as a natural alternative to SO(2) in winemaking.

[Histological alterations of the muscle cremaster in certain inguinal-scrotal anomalies]. / Alteraciones histológicas del músculo cremáster en determinados procesos del canal inguinal.

The alteration in the cremaster muscle has been involved in the pathogeny of certain inguinal-scrotal anomalies, even though there are no conclusive studies up to date. The target of our paper is to determine the eventual existence of alterations in the cremaster muscle (CM) that helps to explain the etiopathogeny of different anomalies such as inguinal hernia, hydrocele or undescended testicle. We carried out a study on 42 patients with: inguinal hernia (n = 14), cryptorchidism (n = 14) and hydrocele (n = 14). Samples of the cremaster muscle were taken during the surgical intervention. Surgical samples were introduced or into formol and glutaraldehyde or into physiological serum and freezing for histological study. They were dyed with hematoxilin-eosin, PAS and phosphotungstic acid haematoxilin. In the histochemical study NADH, phosphoric hydrolases and Engel's trichromic were used. Parameters indicative of myopathic changes were evaluated. All CM samples from all three groups showed myopathic changes of primary type in different levels: first, second and third stages. This changes that produce alterations in the muscle's contractility, changes might make us think in a primary myopathy even though there are data pointing to a neurological influence on it.

Alteraciones histológicas del músculo cremáster en determinados procesos del canal inguinal / Histological alterations of the muscle cremaster in certain inguinal-scrotal anomalies

La alteración en el músculo cremáster se ha implicado en la patogenia de determinados procesos inguinoescrotales, sin que en la actualidad existan estudios concluyentes. El objetivo de nuestro trabajo es determinar si existen alteraciones en el músculo cremáster (MC) que ayuden a explicar la etiopatogenia de distintos procesos como la hernia inguinal, el hidrocele o el mal descenso testicular. Realizamos el estudio en 42 pacientes afectos de: hernia inguinal (n = 14), criptorquidia (n = 14) e hidrocele (n = 14). Se toman muestras del músculo cremáster en el momento de la intervención quirúrgica. Las piezas quirúrgicas fueron repartidas por un lado para inclusión en formol y glutaraldehído y por otro, en suero fisiológico y congelación para estudio histoquímico. Se tiñeron con hematoxilina-eosina, Pas y hematoxilina fosfotúgstica. En el estudio histoquímico se empleó NADH, fosforilasas y el tricrómicro de Engel. Se valoran parámetros indicativos de cambios miopáticos. Todos las muestras de MC de los tres grupos presentaron cambios miopáticos de tipo primario en distinto grado: primer, segundo y tercer estadio. Dichas muestras producen alteraciones en la contractilidad del músculo, lo que podría colaborar en la patogenia de las mismas. Le existencia de cambios miopáticos primarios nos podría hacer pensar en una miopatía primaria, si bien existen datos que apuntan a una participación neurológica en la misma (AU)

The alteration in the cremaster muscle has been involved in the pathogeny of certain inguinal-scrotal anomalies, even though there are no conclusive studies up to date. The target of our paper is to determine the eventual existence of alterations in the cremaster muscle (CM) that helps to explain the etiopathogeny of different anomalies such as inguinal hernia, hydrocele or undescended testicle. We carried out a study on 42 patients with: inguinal hernia (n = 14), cryptorchidism (n = 14) and hydrocele (n = 14). Samples of the cremaster muscle were taken during the surgical intervention. Surgical samples were introduced or into formol and glutaraldehyde or into physiological serum and freezing for histological study. They were dyed with hematoxilin-eosin, PAS and phosphotungstic acid haematoxilin. In the histochemical study NADH, phosphoric hydrolases and Engel´s trichromic were used. Parameters indicative of myopathic changes were evaluated. All CM samples from all three groups showed myopathic changes of primary type in different levels: first, second and third stages. This changes that produce alterations in the muscle´s contractility, changes might make us think in a primary myopathy even though there are data pointing to a neurological influence on it (AU)

[Newly immigrant adolescents health and quality of life in Belgium: screening and prevention in school medicine]. / Santé et qualité de vie des adolescents récemment immigrés en Belgique: dépistage et prévention en médecine scolaire.

OBJECTIVES: Little is known so far about the health of newly immigrant adolescents. The present study aimed to evaluate their health and quality of life (QoL) and to reinforce prevention and health promotion in school medicine. METHODS: One hundred and fifty-eight adolescents (mean age: 15,4 years) from 37 nationalities were included in the study in two health centers in Brussels. This study was carried out by medical records analysis and administration of a questionnaire about health and QoL (VSP-A) in several languages. RESULTS: The results showed adolescents in good physical health. Nevertheless their quality of life deteriorated over time in Belgium. The QoL was significantly lower for adolescents without social support: 48,0 (SD=13,5) vs 60,6 (SD=11,1) compared with adolescents with social support - i.e. with one resource person - on a scale from 0 to 100. Adolescents had many subjective health problems, like "the future" cited by half of them. CONCLUSION: This study shows the importance of developping a specific approach to newly immigrant adolescents health and the contribution of school medicine in the identification of biological, psychological and social needs and hightlights the preventive answers carried out by school medicine.

Aminopeptidase activities in breast cancer tissue.

BACKGROUND: Endopeptidases such as cathepsins help determine the prognosis of breast cancer (BC). However, little information is available about the role in BC of aminopeptidases (APs), which have been implicated in the metabolism of several local hormonal factors. METHODS: Using aminoacyl-beta-naphthylamides as substrates, we measured fluorometrically alanyl-AP, arginyl-AP, cystinyl-AP, glutamyl-AP, aspartyl-AP, and pyroglutamyl-AP activities in their soluble and membrane-bound forms in surgically removed BC tissue from which we separated samples of neoplastic, adjacent tumoral, and unaffected surrounding tissue. RESULTS: Compared with unaffected tissue, neoplastic tissue had significantly higher activities of soluble alanyl-AP (553.9 +/- 82.8 vs 1615.2 +/- 183.0 pmol/mg protein; P <0.001), arginyl-AP (372.4 +/- 56.6 vs 1027.2 +/- 143.5 pmol/mg protein; P <0.001), and cystinyl-AP (74.8 +/- 10.0 vs 282.9 +/- 37.2 pmol/mg protein; P <0.001), and of membrane-bound arginyl-AP (457.7 +/- 97.9 vs 886.6 +/- 140.0 pmol/mg protein; P <0.01). However, membrane-bound aspartyl-AP activity was significantly lower in neoplastic tissue (17.3 +/- 1.4 vs 9.2 +/- 1.2 pmol/mg protein; P <0.05) and pyroglutamyl-AP activity was significantly lower in neoplastic and adjacent tissues (12.8 +/- 0.9 vs 7.0 +/- 1. 2 and 8.0 +/- 1.3 pmol/mg protein; P <0.001 for both comparisons). CONCLUSIONS: The present results document changes in AP activities in BC tissue. These changes may reflect the functional status of the AP substrates, which can be selectively activated or inhibited locally in the affected tissue as a result of specific conditions brought about by the tumor.

Direct myocardial revascularization without extracorporeal circulation: technique and initial results.

In a 10-month period, 68 patients underwent saphenous vein bypass revascularization without extracorporeal circulation. Distal sutures were performed with interruption of coronary flow without any devices for perfusion of the coronary artery; the proximal sutures were completed with tangential clamping of the aorta. Most frequently, the anterior descending and the distal right coronary arteries were revascularized; of 225 patients who underwent bypass surgery, this technique was possible in 68 cases (30.2%). The 30-day hospital mortality was 1.5%, and perioperative myocardial infarction, as determined by daily electrocardiograms (ECGs) and creatine phosphokinase isoenzyme (CKMB), occurred in two patients. Control hemodynamic studies were performed in 22 of the 68 patients (32.4%) with a patency rate of 84.2% in the grafts restudied.

Modified Blalock-Taussig shunt with an umbilical vein graft.

We describe a modification of the Blalock Taussig anastomosis, with the interposition of a glutaraldehyde-tanned umbilical vein graft between the subclavian and pulmonary arteries. This operation was performed in 64 children: 11 were less than 1 month of age (17.2%), and 23 were between 1 and 6 months of age (34.9%). Hospital deaths occurred in six patients-all less than 6 months of age (9.4%). There was no instance of shunt occlusion noted. The clinical course was uneventful among survivors, except for one patient who died of endocarditis in the late postoperative follow-up. The shunt procedure may be performed very rapidly, with minimal dissection, allowing the use of a graft larger than the diameter of the subclavian artery. This modification of the Blalock Taussig operation compares favorably with our previous experience with other shunt procedures and may be considered a valuable alternative in the palliative surgical treatment of several malformations with severe pulmonary oligemia.