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Biomedical subjects

A Marcos

Publications and source records attributed to A Marcos.

At least 37 records · Page 2Linked to original sources
PubMed2002

Functional foods and the immune system: a review.

In the last decade, preventive medicine has undergone a great advance, especially in developed countries. Research has demonstrated that nutrition plays a crucial role in the prevention of chronic diseases, as most of them can be related to diet. Functional food enters the concept of considering food not only necessary for living but also as a source of mental and physical well-being, contributing to the prevention and reduction of risk factors for several diseases or enhancing certain physiological functions. In reference to the immune system, many studies have pointed out that not only pre- and probiotics, but also single micronutrients incorporated into functional foods contribute to an enhancement of immunocompetence. In fact, one of the authorized claims consists of pointing out the immunomodulator properties of functional foods. In this article, the effect of some functional foods and ingredients such as probiotics, selenium and dietary antioxidants (vitamins A, E and C) on the immune function are reviewed. However, the optimum intake level and recommended amounts of functional foods have not yet been established. Thus, in order to remove the controversy surrounding functional food, further research studies are necessary, both in experimental animals and in humans. Finally: efforts should be directed towards the ultimate goal, that is, a 'functional diet'.

Adjuvants, Immunologic↗
PubMed2002

The adaptive response of the immune system to the particular malnutrition of eating disorders.

Despite the seriously undernourished state of patients with anorexia nervosa (AN) and bulimia nervosa (BN), controversial findings have been published regarding some aspects of the immune system that are otherwise impaired in more typical types of malnutrition, such as protein-energy malnutrition. In general, adaptation processes seem to occur enabling immune function to be preserved during long periods of the illness. However, cell-mediated immunity is usually altered in AN and BN as reflected by lymphocyte subset counts and the response to delayed hypersensitivity tests. Regarding the helper/cytotoxic T cell ratio (CD4:CD8), an immunological marker of the nutritional status, the results of our studies on AN and BN patients showed that the duration of the eating disorder and the time when appropriate treatment is achieved are likely contributors to the alteration of this ratio. Despite these findings, it has been repeatedly pointed out that anorexic patients seem to be free of common viral infections at least until the most advanced stages of debilitation. Some hypotheses that could explain the lack of infection symptoms are reviewed. Cytokines and the altered acute phase response to infection, as well as cortisol and leptin, are considered to be potential factors involved in the adaptation processes occurring in these syndromes. Further progress in the knowledge of the psychoneuroendocrine-immune interactions established in AN and BN will be relevant to the understanding of the aetiology and maintenance mechanisms of these pathologies.

Adaptation, Physiological↗
PubMed2002

The implication of the binomial nutrition-immunity on sportswomen's health.

The diet of many athletes is inadequate due to overly restrictive habits and an obsession with losing weight in order to maintain a particular level of body weight. Many female athletes, particularly those who participate in sports that emphasize leanness (gymnastics, distance running, diving, figure skating and classical ballet), have suboptimal energy and nutrient intakes and are at risk of compromised nutritional status, including fatigue, dehydration, nutrient inadequacies, delayed growth and an impaired immunocompetence. It is very well known that active women and girls who are driven to excel in sports may develop the so-called female athlete triad in which malnutrition, amenorrhoea and osteoporosis appear as typical signs of medical complications, frequently linked to serious psychological alterations. This outcome is mainly related to that found in eating disorders-syndromes in which athletes have been defined to be at increased risk. As a consequence of all these alterations, the immune system may be affected in athletes, and subsequently they might be more prone to infections. As there is a lack of knowledge about how the immune system may be affected in basal conditions of athletes, the study of immunocompetence as an index of the nutritional status is reviewed. In summary, it is necessary to encourage all professionals surrounding athletes to be aware of the importance of taking care of their nutritional status in order not only to avoid physical and psychological complications but also to improve performance and, thus, to achieve sporting goals.

Amenorrhea↗
PubMed2002

Influence of alcohol consumption on immunological status: a review.

The aim of this review is to present and discuss the effect of different levels of alcohol consumption on the immune system. Not only the amount consumed but also the type of alcoholic beverage have to be taken into account in order to determine the consequences on activity, number, distribution, balance, interaction and response of immunocompetent cells. The association between alcohol exposure and the risk of developing an alcohol-related disease is multifactorial. In fact, age, gender, smoking habits, dietary intake and exercise are involved among other factors. The evaluation of the host cellular and humoral immune responses has shown that alcohol may induce some benefits when consumption is moderate. Moreover, those alcoholic beverages that contain antioxidants, such as red wine, could be protectors against immune cell damage. According to the literature consulted, the daily consumption of 10-12 g and 20-24 g of alcohol for women and men, respectively, is considered to be a moderate intake; the type of beverage has been established not to be important when defining moderation. Particular attention is often focused on the U- or J-shaped curve which also suggests that light to moderate drinking produces a protective effect. Such an inverse relationship indicates a reduction of risk for both light and moderate consumers and a higher risk not only for hard drinkers, but also for non-consumers.

Alcohol Drinking↗
PubMed2002

Probiotics as a help in children suffering from malnutrition and diarrhoea.

Malnutrition is associated with a significant impairment of cell-mediated immunity, phagocyte function, immunoglobulin A concentrations and cytokine production. This situation-which is unfortunately very frequent in infants and children from developing countries-leads to a high risk of infection, and often to episodes of diarrhoea, hence aggravating the nutritional status. Fermented milks are known to exert a beneficial influence on the host's health. They act by modulating gut microflora, regulating any alteration of gut mucosa and stimulating immune response. A number of studies have shown that probiotics shorten the duration of diarrhoea and prevent recurrence of other episodes. Furthermore, probiotics can prevent diarrhoea from infection in infants with malnutrition. In addition, it has been shown that cytokines could be used as biological markers of both impaired immune system and the immune stimulation of probiotics. The aim of this review is to update the effect of fermented milks in situations of malnutrition and diarrhoea as a consequence of infection as well as the role of cytokines produced by fermented milks in these deficient conditions.

Animals↗
PubMed2002

Chronobiological features of the immune system. Effect of calorie restriction.

The circadian organization of living organisms is fully established being a key component the activity of the neuro-endocrin-immune system that maintains the homeostasis. Secondary lymph organs, such as submaxillary lymph nodes and spleen, have been shown to exhibit a 24 h variation in blastogenic proliferative capacity and distribution of B and T subsets, with specific achrophases depending on the parameter studied or the lymphoid organ considered. However, less is known about the thymus. The immune system has been shown to change by calorie restriction, although no information is available about possible effects in 24 h variations. Similar questions can be posed for the neuro-endocrine system. As an example, some data are shown in this article about the effects of calorie restriction on the neuro-endocrin-immune system in growing male Wistar rats. Calorie restriction blunted the circadian secretory pattern of TSH observed in the control group that was characterized by the existence of two peaks at 17:00 or 01:00 h and that explained the low basal metabolic rate of these animals under this experimental condition. Concerning the immune system, the thymus gland exhibited 24 h variations in T, B and immature cells in both control and calorie-restricted male rats, thus confirming the circadian organization of the immune system. Moreover this circadian organization was changed by calorie restriction.

Animals↗
PubMed2002

The effect of fermented milk on interferon production in malnourished children and in anorexia nervosa patients undergoing nutritional care.

For several years cytokine production has been associated with infections but it was not suspected that some types of food could also induce cytokines, even in a state of non-infection. Lactic bacteria can induce interferon (IFN) production in human healthy subjects, thus, a better protection against infections would be expected. Therefore, we planned to evaluate the effect of two diets including yoghurt or milk on IFN-gamma production during nutritional recovery in two different situations of malnutrition: (1) children with diarrhoea; and (2) patients with anorexia nervosa (AN). Both the diet including yoghurt of that including milk seemed to increase IFN-gamma production at the end of nutritional recovery in the malnourished children with diarrhoea. The significance of interferon production and the lymphocyte subset increase should be explored to know if a better resistance against pathogens is related to them. Regulation of intestinal absorption and moderate stimulation of interferon production make the yoghurt-based diet a good choice in the nutritional care of children. In the same way, an increase in the IFN-gamma production was observed in AN patients consuming yoghurt. This increase of IFN-gamma production could be considered a biological marker to detect the effect of probiotics on the immune response, especially in the improvement of a deficient nutritional status.

Adolescent↗
PubMed2001

Adult-to-adult living donor liver transplantation.

Adult-to-adult living donor liver transplantation has become the subject of a great deal of attention over the last few years. Until the use of the donor right lobe was introduced and demonstrated to be relatively safe, it was not possible to offer this alternative to conventional transplantation to most adults. Recent clinical work has focused on the results of these procedures in both donors and recipients, perfecting surgical techniques for right-lobe transplantation, streamlining donor evaluation protocols, and containing costs. This overview summarizes many of the recent publications and presentations in the field of adult-to-adult living donor liver transplantation.

Anastomosis, Surgical↗
PubMed2001

A one-year follow-up study in anorexia nervosa. Dietary pattern and anthropometrical evolution.

OBJECTIVE: To find out the modifications and the interrelationships between the energy and macronutrient intakes and anthropometric measurements of a group of anorexia nervosa patients (ANP), with homogenous diagnosis, age and treatment, during a 1 y follow-up. DESIGN: Longitudinal study design. SUBJECTS: Fourteen restricting-type ANP in the adolescent age (11-21 y) were recruited for the study and evaluated at four time intervals during 1 y of multidisciplinary treatment: (a) on admission (AN0); (b) after 1 month (AN1); (c) after 6 months (AN6); (d) after 1 y (AN12). MEASURES: Energy and macronutrient composition of the diet (48 h recall) and anthropometric measurements including skinfold thickness. RESULTS: Mean weight and BMI were under the 3rd percentile in AN0. All anthropometrical parameters increased significantly in AN1 compared to AN0 and did not change in AN6 and AN12. Energy and macronutrient intakes increased significantly in AN1. The dietary changes were not maintained in the subsequent time intervals and there was an overall tendency to turn back to AN0 results. Energy intake adequacy to Spanish Recommended Intakes (RI) showed only an acceptable ratio in AN1 (94% RI); however, a preserved protein intake was found throughout the study (mean intakes between 128.5% and 230.0% RI). Negative correlations were found at AN12 between size of arm's subcutaneous fat stores and energy and macronutrient intakes. CONCLUSION: In this 1 y follow-up study the decrease in the intake of energy and macronutrients after discharge seems to be related to anthropometric evolution, so that a return to restrictive eating behaviour had occurred in those subjects who had reached the highest values in their subcutaneous fat stores, probably related to dissatisfaction with self-body image.

Adolescent↗
PubMed2001

Evaluation of the effect of data pre-treatment procedures on classical pattern recognition and principal components analysis: a case study for the geographical classification of tea.

A simple transformation that uses the half-range and central value has been used as a data pre-treatment procedure for principal component analysis (PCA) and pattern recognition techniques. The results obtained have been compared with the results from classical normalisation of data (mean normalisation, maximum normalisation and range normalisation), autoscaling and the minimum-maximum transformation. Three data sets were used in the study. The first was formed by determining 17 elements in 53 tea samples (901 pieces of data). The second and third data sets arose from two long-term drift studies performed to examine instrumental stability at standard and robust conditions. The instruments used were an inductively coupled plasma atomic emission spectrometer and an inductively coupled plasma mass spectrometer. Each drift diagnosis experiment consisted of replicate determinations of a test solution containing 15 analytes at 10 mg l-1 over 8 h without recalibration. Twenty-nine emission lines were determined 99 times, thus, each data set was formed by 2881 pieces of data. Data pre-treatment was applied to the three data sets prior to the use of principal component analysis, cluster analysis, linear discrimination analysis and soft independent modelling of class analogy. The study revealed that the half-range and central value transformation resulted in a better classification of the tea samples than that achieved using the classical normalisation. The loadings in the PCA for the long-term stability study, under both standard and robust conditions, were found to be similar to the drift trends only when the minimum-maximum transformation and the mean or maximum normalizations were used as data pre-treatments.

Humans↗
PubMed2001

Double aortic arch in a dog (Canis familiaris): a case report.

We herein report a case of a double aortic arch in a 10-week-old male dog of no defined race, which presented episodes of regurgitation at the time of weaning. This vascular malformation was characterized by the persistence of two aortic arches, right and left, of varying dimensions. The right aortic arch was observed to be larger. During post mortem examination the vessels of the animal were injected with coloured latex bi-centrifuged CIS 1-4 polisopreno which revealed the patency of the two aortic arches. Concomitantly, dilation of the cranial oesophagus causing constriction was observed, indicating megaesophagus. Apart from the constriction, the oesophagus presented normal morphometric parameters in relation to its dimensions.

Animals↗
PubMed2001

Obesity and immune function relationships.

The immunological processes involved in the collaborative defence of organisms are affected by nutritional status. Thus, a positive chronic imbalance between energy intake and expenditure leads to situations of obesity, which may influence unspecific and specific immune responses mediated by humoral and cell mediated mechanisms. Furthermore, several lines of evidence have supported a link between adipose tissue and immunocompetent cells. This interaction is illustrated in obesity, where excess adiposity and impaired immune function have been described in both humans and genetically obese rodents. However, limited and often controversial information exist comparing immunity in obese and non-obese subjects as well as about the cellular and molecular mechanisms implicated. In general terms, clinical and epidemiological data support the evidence that the incidence and severity of specific types of infectious illnesses are higher in obese persons as compared to lean individuals together with the occurrence of poor antibody responses to antigens in overweight subjects. Leptin might play a key role in linking nutritional status with T-cell function. The complexities and heterogeneity of the host defences concerning the immune response in different nutritional circumstances affecting the energy balance require an integral study of the immunocompetent cells, their subsets and products as well as specific and unspecific inducer/regulator systems. In this context, more research is needed to clarify the clinical implications of the alterations induced by obesity on the immune function.

Adipose Tissue↗
PubMed2001

Wheat germ agglutinin-binding glycoproteins are decreased in Alzheimer's disease cerebrospinal fluid.

A number of biomarkers (e.g. Abeta, tau) has been identified in Alzheimer's disease CSF. However, none fulfils the criteria of sensitivity and specificity (> 80%) needed for the development of an accurate diagnostic test. The lack of a suitable marker has prompted the search for new CSF biomarkers. In this study, the glycosylation of CSF proteins was examined using lectin blotting. Lumbar CSF was collected ante mortem from 22 non-Alzheimer's disease and 12 probable Alzheimer's disease cases and ventricular CSF collected post mortem from 7 non-Alzheimer's disease and 16 Alzheimer's disease cases confirmed by pathologic examination. When CSF glycoproteins were stained with wheat germ agglutinin (WGA), the staining intensity was found to be significantly lower in the Alzheimer's disease group. No difference in staining was found using other lectins (Canavalia ensiformis agglutinin, Ricinus communis agglutinin, Lens culinaris agglutinin). The measurement of WGA-reactive glycoproteins in CSF may be a useful biomarker for diagnosis of Alzheimer's disease.

Aged↗
PubMed2001

Reconstruction of double hepatic arterial and portal venous branches for right-lobe living donor liver transplantation.

Double hepatic arterial and portal venous branches are common anatomic variations of the isolated right hepatic lobe. Reconstruction of these vessels during transplantation can be challenging because of their small caliber, close proximity to other hilar structures, and abnormal alignment with the native vasculature. Practical techniques for the creation of these anastomoses would simplify the recipient surgery and might minimize the incidence of vascular complications. Alternative methods for management of these structures are summarized. The recipient's proper hepatic artery and its bifurcation are resected for use as an arterial Y-type graft. The donor arteries are individually anastomosed at the bifurcation of the recipient's hepatic artery at the back table. The free end of the Y graft is then replaced at the origin of the gastroduodenal artery using standard branch-patch technique. Reconstruction of a second donor portal branch is similarly facilitated by ex situ placement of a Y-type vascular conduit derived from the recipient's portal vein. Surgical management of these vessels and reconstruction of other hilar structures are noticeably less cumbersome. There have been no short-term vascular complications. The use of autologous vascular conduits with ex situ reconstruction facilitates management of double donor arterial and portal venous branches. The incidence of complications attributable to these methods is expected to be low.

Angiography↗
PubMed2001

Functional venous anatomy for right-lobe grafting and techniques to optimize outflow.

Right-lobe living donor liver transplantation has emerged as an alternative to cadaveric transplantation. An appreciation of the unique anatomy and behavior of the right lobe has emerged and has precipitated technical modifications. Living donors underwent right lobectomy, including preservation of significant inferior hepatic veins. The parenchyma was divided following a plane approximating the right border of the posterior two thirds of the midhepatic vein (MHV), but deviating anteriorly to include the distal one third of the MHV with the graft. Large venous tributaries from segment VIII were preserved. Anastomosis in the recipient was accomplished by means of complete cavoplasty. Significant inferior veins, tributaries to the MHV, and the distal portion of the MHV were reconstructed when technically possible. Forty-eight right-lobe resections and transplantations were performed in the manner described. There were no donor complications attributable to the technique. Forty-six of the 48 recipients are alive, and 44 of the 46 surviving patients have their original graft. Venous tributaries from segment VIII and/or the distal portion of the MHV were reconstructed in only 3 patients. Outflow obstruction was recognized intraoperatively in 2 patients; 1 patient had a caval web excised and the other patient required revision of the main anastomosis. Neither organ was lost. There were no other significant venous complications. The incidence of ascites was the same as that in recipients of whole organs. These methods of parenchymal transection and venous reconstruction resulted in a low rate of complications. The wide anastomosis and collateral pathways between the MHV and right hepatic vein seem to be more critical than reconstruction of tributaries from segment VIII or the distal MHV.

Adult↗
PubMed2001

Ethical considerations and rationale of adult-to-adult living donor liver transplantation.

Adult-to-adult living donor liver transplantation (ALDLT) is a reality; shortly after its introduction into clinical practice, it is being performed in approximately 50 centers throughout the United States and Europe. The quick development of ALDLT and some deaths among donors repropose old ethical dilemmas and confront the transplant community with new urgent problems. To minimize risks for recipients and, especially, donors, two key questions are addressed: (1) who can or should perform the procedure, and (2) what patient should undergo the procedure. The high risks taken by live donors undergoing a hemihepatectomy seem to be justified by the steadily increasing mortality of adult recipients waiting for transplantation. A comprehensive consent procedure is at the base of responsible decision making for both donors and recipients. In adherence to basic medical criteria, the autonomy of decision of donors and recipients may allow the extension of indications to patients not suitable to undergo transplantation with cadaveric grafts. The broadening of indications is appropriate only in centers with adequate experience and proven expertise in ALDLT. The medical community faces the duty of regulating ALDLT before external influences force undesired policy changes, particularly if not based on medical grounds. Individual centers and patients are ultimately responsible for the correct use of LDLT.

Adult↗