A virtual dairy herd as a tool to teach dairy production and management.

The objective of this project was to develop and test a web-based virtual dairy herd to help students understand the structure and functioning of a dairy herd, and to promote active learning. At the beginning of the course, the instructor defines the profiles of herds to be assigned to students (e.g., herd size, production, diets, fertility). Each student has a unique herd and engages in decision-making for desired management practices in the herd. Modeled events are based on cow physiology and normal dairy herd management practices. Students' activities and decisions include heat detection, insemination, pregnancy diagnosis, dry-off, diet specifications, feeding groups, colostrum and milk-replacer feeding, weaning, treatment of diseases, and milk withdrawal from the tank if antibiotics are used, among others. The daily output provides information on technical indexes, economic performance, counters of incorrect decisions as feedback for students, and score. Time in class can be devoted to discussions of dairy management issues. Additional exercises based on students' own herds (e.g., calculating required space for cows, land for forage production, manure management) can also be implemented. Students' performance in the virtual dairy farm was monitored over 3 years. The average score (n = 326) was 87.8 ± 1.1 over 100 points, suggesting that self-learning with the virtual dairy farm was highly successful. At the end of each semester, students (n = 277) responded to a survey on the experience of working with the virtual dairy herd. Most students (>87%) agreed that the virtual dairy herd was more effective and motivating than traditional lectures and helped them understand dairy production better. In an unannounced test conducted at least 2 wk before the final exam, students (n = 207) were asked 14 questions on dairy cattle and 14 similar questions on other species taught in the same class through traditional lectures. A similar test on the same students (n = 142) was conducted in their fifth semester (2 years later). Results were better in dairy compared with other species questions in the first (9.6 vs. 3.7) and fifth (8.0 vs. 3.8) semesters. The virtual dairy herd is an effective tool for teaching introductory courses in dairy production. The program can be accessed at www.virtualdairyfarm.org, and a manual and videos with instructions for instructors and students are available online.

Cannabinoid pharmacology and therapy in gut disorders.

Cannabis sp. and their products (marijuana, hashish…), in addition to their recreational, industrial and other uses, have a long history for their use as a remedy for symptoms related with gastrointestinal diseases. After many reports suggesting these beneficial effects, it was not surprising to discover that the gastrointestinal tract expresses endogenous cannabinoids, their receptors, and enzymes for their synthesis and degradation, comprising the so-called endocannabinoid system. This system participates in the control of tissue homeostasis and important intestinal functions like motor and sensory activity, nausea, emesis, the maintenance of the epithelial barrier integrity, and the correct cellular microenvironment. Thus, different cannabinoid-related pharmacological agents may be useful to treat the main digestive pathologies. To name a few examples, in irritable bowel syndrome they may normalize dysmotility and reduce pain, in inflammatory bowel disease they may decrease inflammation, and in colorectal cancer, apart from alleviating some symptoms, they may play a role in the regulation of the cell niche. This review summarizes the main recent findings on the role of cannabinoid receptors, their synthetic or natural ligands and their metabolizing enzymes in normal gastrointestinal function and in disorders including irritable bowel syndrome, inflammatory bowel disease, colon cancer and gastrointestinal chemotherapy-induced adverse effects (nausea/vomiting, constipation, diarrhea).

Enfermedad de Grover, una patología ampollar poco frecuente: a propósito de 2 casos / Grover's disease, a pathology blistering unusual: About 2 cases

Grover's disease (GD) or transient acantholytic dermatosis, is a papulovesicular pruritic disease of unknown etiology. It´s most important histopathological finding is the presence of focal acantholysis. The incidence has not been firmly established. Case report: We report two cases of papulovesicular rashes, the first one in a 79 year old man with good response to second line treatment and the second one, in a 30 year old woman. Both with different suspected triggering factors. Comment: GD predominates in white men with an average age of presentation of 61. Clinically, it presents as erythematous papules, crusted-papule and is usually pruritic. The etiopathology is still unknown, but it is associated with triggers such as: ultraviolet radiation (UVR), ionizing radiation, heat, sweat, friction and chemotherapy. Acantholysis is the classic histological finding. Management includes general measures, topical corticosteroids, calcineurin inhibitors, tretinoin, calcipotriene and antihistamines. In refractory cases, second-line treatment is used: oral isotretinoin, systemic corticosteroids and phototherapy. Paradoxically, phototherapy can also trigger GD. Conclusions: Due to the low prevalence of GD in Chile, 2 new cases are provided to the literature. In both cases, the diagnostic presumption was based on an exhaustive clinical history, confirmed by histopathological findings. (AU)

Identification of an osteopontin-like protein in fish associated with mineral formation.

Fish has been recently recognized as a suitable vertebrate model and represents a promising alternative to mammals for studying mechanisms of tissue mineralization and unravelling specific questions related to vertebrate bone formation. The recently developed Sparus aurata (gilthead seabream) osteoblast-like cell line VSa16 was used to construct a cDNA subtractive library aimed at the identification of genes associated with fish tissue mineralization. Suppression subtractive hybridization, combined with mirror orientation selection, identified 194 cDNA clones representing 20 different genes up-regulated during the mineralization of the VSa16 extracellular matrix. One of these genes accounted for 69% of the total number of clones obtained and was later identified as theS. aurata osteopontin-like gene. The 2138-bp full-length S. aurata osteopontin-like cDNA was shown to encode a 374 amino-acid protein containing domains and motifs characteristic of osteopontins, such as an integrin receptor-binding RGD motif, a negatively charged domain and numerous post-translational modifications (e.g. phosphorylations and glycosylations). The common origin of mammalian osteopontin and fish osteopontin-like proteins was indicated through an in silico analysis of available sequences showing similar gene and protein structures and was further demonstrated by their specific expression in mineralized tissues and cell cultures. Accordingly, and given its proven association with mineral formation and its characteristic protein domains, we propose that the fish osteopontin-like protein may play a role in hard tissue mineralization, in a manner similar to osteopontin in higher vertebrates.

A comparison between an in vitro method to determine carbohydrate digestion rate and the glycemic response in young men.

OBJECTIVE: This study examines the relationship between the results of in vitro determinations of carbohydrate digestion rates and the glycemic index. SUBJECTS: Ten healthy non smoking men, aged between 21 and 24-y-old, were selected to participate in the study. METHODS: Six different meals with similar levels of carbohydrates were assayed at breakfast in ten subjects and blood samples were obtained at 0, 15, 30, 60 and 120 min to determine glucose levels. The Englyst's enzymatic method was used in the in vitro study. The six meals were based in cereals (rice or spaghetti); legumes (lentil soup and beans with spaghetti); and potato (potato stew with meat and vegetables). RESULTS: The meals showed different glycemic indices: rice and spaghetti based meals had lower values (mean value 31.4 and 42, respectively); the intermediate values corresponded to lentil soup and the bean dish (49.3, and 76.8 respectively) and the higher glycemic index was shown by the potato based meal (82). CONCLUSIONS: A significant correlation was observed when the ratio of rapid carbohydrate digestion rate and the lente carbohydrate digestion rate was correlated with the glycemic index of the meals, but not when only the rapid carbohydrate digestion rate was considered. These results demonstrate a useful, simple and inexpensive method to estimate the biological response of high carbohydrate meals.

[Effect of dietary polyunsaturated fatty acids on the content and metabolism of glutathione in rat kidney]. / Contenido de glutation en riñon de ratas: effecto del aumento de los acidos grasos poliinsaturados dieteticos.

The effect of dietary polyunsaturated fatty acids (PIFA) upon the content of reduced glutathione (GSH) of the kidney was studied in 32 male Wistar rats. Two equal size groups were fed diets supplemented with either 10% or 18% corn oil. Sixteen hours before death, half of each experimental group was submitted to fasting. The content of GSH and the activity of gamma glutamyl transpeptidase (GGTP) and gamma glutamyl cysteine synthetase was determined in kidney tissue. Fasting led to a reduction of GSH from 3.21 +/- 0.54 to 1.25 +/- 0.20 mumol per gm in the group fed 10%. PIFA. Equivalent figures for the group fed 18% PIFA were 3.49 +/- 0.54 and 0.49 +/- 0.08, respectively. GGTP activity increased significantly after fasting but no differences were observed according to level of PIFA intake. The exaggerated reduction of GSH during fasting after a high PIFA intake may expose the animals to risk of cell damage induced by peroxides or other oxidating agents.

Effect of diet composition on renal morphology in diabetic rats.

Streptozotocin-induced diabetic rats were fed rodent diets with standard (4.5%) or high (10%) polyunsaturated fatty acid content for up to 12 months. Diabetic rats fed a standard diet developed thickening of glomerular basement membrane (GBM) when compared to similarly fed controls (285 +/- 21 vs. 243 +/- 18 nm, respectively; p = 0.0003). No differences in GBM thickening were observed between control and diabetic rats fed high-fat diets (188 +/- 23 vs. 195 +/- 21 nm, respectively; p = n.s.). Regardless of diabetes, all rats fed high polyunsaturated fat diets had decreased GBM thickness compared to standard-fed rats (p = 0.0001). Glomerular and mesangial volumes were similar in control and diabetic rats fed standard or high fat diets. Diets high in polyunsaturated fatty acids prevent GBM thickening in diabetes and reduce GBM thickness in control rats.

[Effect of increase of dietary polyunsaturated fatty acids (omega 6) on the hepatic glutathione content and gamma-glutamil transpeptidase activity in the kidney of rats]. / Efecto del aumento de los ácidos grasos poliinsaturados (omega 6) dietéticos en el contenido de glutatión hepático y actividad de gama glutamil transpeptidasa en riñón de ratas.

The effect of feeding 24 to 52-days-old male rats of the Wistar strain, with beans diet deficient in sulfur-containing amino acids or supplemented with 0.3% DL-methionine and two corn oil concentrations, 2% and 20% (g/kg/diet), on the glutathione content (GSH) in liver, and on the renal gamma glutamyl transpeptidase (GGTP) (E.C.2.3.2.2) activity was studied. Results indicated that rats fed the bean diet with 2% corn oil decreased significantly the liver GSH content and GGTP renal activity. Supplementation with 0.3% methionine and/or the 20% increment of the diet corn oil, significantly stimulated the liver GSH content and the transpeptidase activity in the kidney. It is postulated that the increase of polyunsaturated fatty acids, stimulated the GGTP activity as a way of increasing substrate bioavailability for synthesis de novo of liver GSH, necessary for the protection of the hydroperoxides formation, attributed to the increment of polyunsaturated acids at cellular level.

[Soluble and insoluble dietary fiber in cereals and legumes cultivated in Chile]. / Fibra dietética soluble e insoluble en cereales y leguminosas cultivadas en Chile.

Insoluble, soluble and total dietary fiber (DF) were determined in 35 varieties of certified whole seeds (without processing) of cereals (rice, oat, rye, and wheat) and legumes (pea, cowpea, beans, chikpea, lentil and lupine). The enzymatic method of Asp, Johansson and Siljestrom was used, with modifications in relation to time of incubation with alpha amylase, filtration system and volumes of the filtrates. Results were expressed as g/100 g dry weight. Total DF for cereals showed a range from 10.1 (wheat var. Chasqui) to 22.2 (rice var Quella). Rye, var. Tetra Baer and oats var. Pony Baer presented the highest soluble fiber content (3.3 and 3.9, respectively). In legumes, total DF fluctuated between 12.7 (pea, var. yellow) and 36.6 (lupine, var. Multolupa). Bean, var. Pinto INIA and lupine var. Multolupa presented the highest soluble fiber values (5.8 for both). Based on the results of this research work, it might be concluded that great variation exists in regard to the amount of total soluble and insoluble DF in cereals and legumes, a fact which impedes generalization as to its content in each food item.

[Legume consumption among pre-school children: effect of energy density and type of preparation]. / Consumo de leguminosas en preescolares: efecto de la densidad energética y tipo de preparación.

The objective of this study was to evaluate the effect of the energy density (E.D.), children's age and type of meals on the consumption of dishes based on legumes and its combination with cereals by preschool children, for the purpose of defining if they were adequate for preschool children's feeding. Thirty children aged 2 to 5 years old who lived in a foster home, were assigned to three experimental groups. Each group was formed by 10 children. Twenty-nine meals were offered to all groups, differing in their energy density: 0.85, 0.94 and 1.03 kcal/g in dishes of legumes and cereals, and 0.47, 0.62 and 0.80 kcal/g in soups. The study was conducted during 29 non-consecutive days throughout a period of 80 days. Food consumption of each child was determined by differential weighing. Food and energy consumption of the legume-cereal dishes was significantly higher than those observed in the case of soups (312 vs 223 g and 288 vs 138 kcal, respectively). The effect of age was verified only when the volume and energy intake was expressed by kg of body weight, being the group with the highest age which showed the lowest food and energy intake, either in dishes or in soups. The relationship between meal consumption and E.D. was significantly inverse. Dishes based on legume-cereal were consumed by pre-school children in sufficient amounts to satisfy their energy requirements in one meal, when these meals have an E.D. of 1.03 kcal/g (3% of added oil). The low E.D. of soups conditioned the fact that these meals were inadequate for the feeding of this age group.

[Index of nutritional quality per volume: a new indicator to evaluate the nutritional quality of food preparations and diets]. / Indice de calidad nutricional por volumen (ICNV): un nuevo indicador para evaluar la calidad nutricional de preparaciones y dietas.

The purpose of this study was to propose a new dietary index to evaluate the nutritional quality of common dishes and diets: the index of nutritional quality per volume (INQV). In its expression, this index takes into account the nutrient density (amount of nutrient/1,000 g of diet) and the nutrient density per reference volume. The last one is the ratio between the recommended allowances of the nutrient and the volume that it is possible to consume during the day, when the diet is offered freely. Zinc was used as example in the analysis. A total of 14 dishes of habitual consumption in Chile were studied in relation to its consumption by 30 preschool children. The volume that children were able to consume was determined by differential weighing between the amount offered and the amount left on the dish, during a period of 180 days. The percentage of water and energy value were established by means of chemical analysis performed according to the AOAC, and the zinc concentration by atomic absorption spectrophotometry. The results of the INQV were then compared with those of the index of nutritional quality (INQ), which considers zinc density/1,000 kcal, and zinc and energy requirements. This comparison demonstrated that the INQV values were lower than those of the INQ in dishes with energy densities lower than 1.0 kcal/g. The opposite tendency was observed in the case of those dishes with energy densities higher than 1.0 kcal/g. The analysis herein presented demonstrates the usefulness of the INQV in diets which are voluminous and with low energy densities, commonly consumed by the low socioeconomic strata of developing countries.

[Analysis of the application of methods recommended by FAO/WHO 1973 for determining the protein quality in Chilean food. Effect of the dietary protein concentration]. / Análisis de la aplicación de los métodos recomendados for FAO/OMS 1973 para determinar calidad proteínica en alimentos chilenos. Efecto de la concentración de la proteína dietaria.

The 1973 FAO/WHO Joint Expert Committee on Energy and Protein Requirements has recommended two methods to adjust the safe level of protein intake according to protein quality: chemical score and net protein utilization (NPU). However, the effect of protein concentration on protein utilization is not considered. The results of the present work, as well as those obtained by other investigators, show that there is an inverse relationship between protein concentration and protein utilization. The net protein utilization (NPU) at 10% of protein-calories or the chemical score adjusted by the nitrogen digestibility can be applied when results are to be projected to national average diets, which have values ranging between 9 and 13%. When it is necessary to evaluate the diet of specific relatively homogeneous population groups, the recommended method should use the NPU determined or calculated in each meal considering the level of protein concentration of the diet as eaten (NPU op). This method takes into account the amino acid complementation in each meal. The data on which these conclusions are based have been presented and discussed.