Showing papers by "Rowett Research Institute published in 2009"
TL;DR: Findings are discussed that address aspects of the fate, transport, and persistence of antibiotics and antibiotic resistance genes in natural environments, with emphasis on mechanisms pertaining to soil environments following land application of animal waste effluent.
Abstract: Antibiotics are used in animal livestock production for therapeutic treatment of disease and at subtherapeutic levels for growth promotion and improvement of feed efficiency. It is estimated that approximately 75% of antibiotics are not absorbed by animals and are excreted in waste. Antibiotic resistance selection occurs among gastrointestinal bacteria, which are also excreted in manure and stored in waste holding systems. Land application of animal waste is a common disposal method used in the United States and is a means for environmental entry of both antibiotics and genetic resistance determinants. Concerns for bacterial resistance gene selection and dissemination of resistance genes have prompted interest about the concentrations and biological activity of drug residues and break-down metabolites, and their fate and transport. Fecal bacteria can survive for weeks to months in the environment, depending on species and temperature, however, genetic elements can persist regardless of cell viability. Phylogenetic analyses indicate antibiotic resistance genes have evolved, although some genes have been maintained in bacteria before the modern antibiotic era. Quantitative measurements of drug residues and levels of resistance genes are needed, in addition to understanding the environmental mechanisms of genetic selection, gene acquisition, and the spatiotemporal dynamics of these resistance genes and their bacterial hosts. This review article discusses an accumulation of findings that address aspects of the fate, transport, and persistence of antibiotics and antibiotic resistance genes in natural environments, with emphasis on mechanisms pertaining to soil environments following land application of animal waste effluent.
701 citations
TL;DR: The development of an immunoassay based on a monoclonal antibody for free deoxypyridinoline (Dpd) and its use in healthy individuals and patients with bone‐related disorders to measure the urinary excretion of Dpd as an improved assessment of bone resorption rate are described.
Abstract: Several studies in recent years have shown that the pyridinium crosslinks of collagen provide good urinary markers of collagen degradation, primarily reflecting bone resorption. Most studies, however, were based on time-consuming HPLC assays of the crosslinks. We now describe the development of an immunoassay (ELISA) based on a monoclonal antibody for free deoxypyridinoline (Dpd) and its use in healthy individuals and patients with bone-related disorders to measure the urinary excretion of Dpd as an improved assessment of bone resorption rate. The Dpd antibody exhibited less than 1% cross-reaction with free pyridinoline and was shown to react only with free Dpd in urine, having no significant interaction with peptide forms of the crosslinks. The intra- and interassay variations were less than 10 and 15%, respectively. A total of 402 urine samples from patients and healthy volunteers were analyzed by both the immunoassay and HPLC. The ELISA results were highly correlated with those for total Dpd measured by HPLC over the full range of sample groups (r = 0.95). In normal adults, the excretion of Dpd (mean +/- SD) was 4.7 +/- 1.6 nmol/mmol creatinine, with about fivefold higher excretion rates in children. For 31 osteoporotic patients, the ELISA Dpd values (median 6.7; range 3.0-13.5 nmol/mmol Cr) were significantly higher (p < 0.0001) than the corresponding values for age- and sex-matched controls (median 4.0; range 1.8-7.4). The difference between the groups was similar for total Dpd by HPLC (osteoporotic: mean 12.8, range 4.8-30.7; controls: 6.6, range 3.0-18.1; p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
311 citations
TL;DR: This review discusses a selection of available modeling approaches and applications relevant for nutrition and identifies a dearth of models that consider processes occurring between the microscopic and macroscopic scale, and proposes a “middle-out” strategy to develop the required full-scale, multilevel computational models.
Abstract: The use of computational modeling and simulation has increased in many biological fields, but despite their potential these techniques are only marginally applied in nutritional sciences. Nevertheless, recent applications of modeling have been instrumental in answering important nutritional questions from the cellular up to the physiological levels. Capturing the complexity of today's important nutritional research questions poses a challenge for modeling to become truly integrative in the consideration and interpretation of experimental data at widely differing scales of space and time. In this review, we discuss a selection of available modeling approaches and applications relevant for nutrition. We then put these models into perspective by categorizing them according to their space and time domain. Through this categorization process, we identified a dearth of models that consider processes occurring between the microscopic and macroscopic scale. We propose a "middle-out" strategy to develop the required full-scale, multilevel computational models. Exhaustive and accurate phenotyping, the use of the virtual patient concept, and the development of biomarkers from "-omics" signatures are identified as key elements of a successful systems biology modeling approach in nutrition research - one that integrates physiological mechanisms and data at multiple space and time scales. © 2009 de Graaf et al.
154 citations
TL;DR: This study provides the first example of porcine extrahepatic expression and regulation of C-reactive protein, haptoglobin, fibrinogen, pig major acute phase protein, and transferrin in peripheral lymphoid tissues and suggests that the acute phaseprotein response is a more disseminated systemic response than previously thought.
Abstract: The acute phase protein response is a well-described generalized early host response to tissue injury, inflammation and infection, observed as pronounced changes in the concentrations of a number of circulating serum proteins. The biological function of this response and its interplay with other parts of innate host defence reactions remain somewhat elusive. In order to gain new insight into this early host defence response in the context of bacterial infection we studied gene expression changes in peripheral lymphoid tissues as compared to hepatic expression changes, 14-18 h after lung infection in pigs. The lung infection was established with the pig specific respiratory pathogen Actinobacillus pleuropneumoniae. Quantitative real-time PCR based expression analysis were performed on samples from liver, tracheobronchial lymph node, tonsils, spleen and on blood leukocytes, supplemented with measurements of interleukin-6 and selected acute phase proteins in serum. C-reactive protein and serum amyloid A were clearly induced 14-18 h after infection. Extrahepatic expression of acute phase proteins was found to be dramatically altered as a result of the lung infection with an extrahepatic acute phase protein response occurring concomitantly with the hepatic response. This suggests that the acute phase protein response is a more disseminated systemic response than previously thought. The current study provides to our knowledge the first example of porcine extrahepatic expression and regulation of C-reactive protein, haptoglobin, fibrinogen, pig major acute phase protein, and transferrin in peripheral lymphoid tissues.
91 citations
TL;DR: The results demonstrate that the immunoassay technique provides measurements of pyridinium crosslinks that are highly correlated with HPLC findings, and beyond age 50, urinary concentrations of total and free PYD and DPD are not linearly influenced by age or anthropometric factors but change with sex independently of osteoporotic status.
Abstract: The urinary pyridinium crosslinks pyridinoline (PYD) and deoxypyridinoline (DPD) have been shown to provide valid indices of bone resorption. At present, both crosslink components are determined by reversed-phase HPLC, a time-consuming method precluding the use of these markers for routine purposes. Therefore, efforts have been made to develop simple immunoassays for the rapid measurement of urinary crosslinks, and their application to large-scale osteoporosis screening has been proposed. To evaluate the applicability and diagnostic validity of pyridinium crosslink measurements for screening purposes, urinary concentrations of total and free PYD and DPD were determined by HPLC and immunoassay technique (ELISA) in a sample of 269 individuals (male to female ratio = 130:139; age 50-81 years) recruited at random within a population survey of vertebral osteoporosis. On a molar basis, ELISA measures of crosslink-related epitopes were highly correlated with both total and free PYD and DPD as determined by HPLC (r > 0.82, p < 0.001). Age-specific means for creatinine-corrected total and free pyridinium crosslinks were significantly higher in females than in males (p < 0.001). In both sexes, neither age nor anthropometric variables (weight, height, and body mass index) showed a linear effect on the urinary crosslink/creatinine ratio. On average, 50% of the total amount of urinary crosslinks were present in free form. For both PYD and DPD, this proportion was significantly higher in women than in men (p < 0.05), but no change was observed with age or anthropometric measures. The excretion of pyridinium crosslinks was higher in osteoporotic (n = 18) than in nonosteoporotic individuals (n = 208) from the same population.(ABSTRACT TRUNCATED AT 250 WORDS)
87 citations
TL;DR: In this paper, the authors examined the effect of iron deficiency and supplementation on the hierarchy of iron supply and gene expression of proteins that regulate iron metabolism in the rat, and found that iron levels in the fetal, and not maternal, liver regulate the expression of liver transferrin receptor and hepcidin expression in the mother.
Abstract: Iron metabolism during pregnancy is biased toward maintaining the fetal supply, even at the cost of anemia in the mother. The mechanisms regulating this are not well understood. Here, we examine iron deficiency and supplementation on the hierarchy of iron supply and the gene expression of proteins that regulate iron metabolism in the rat. Dams were fed iron-deficient diets for 4 wk, mated, and either continued on the deficient diet or an iron-supplemented diet during either the first half or the second half of their pregnancy. A control group was maintained on normal iron throughout. They were killed at 0.5, 12.5, or 21.5 days of gestation, and tissues and blood samples were collected. Deficiency and supplementation had differential effects on maternal and fetal hematocrit and liver iron levels. From early in pregnancy, a hierarchy of iron supply is established benefiting the fetus to the detriment of the mother. Transferrin receptor, transferrin receptor 2, and hepcidin mRNA expression were regulated by both iron deficiency and supplementation. Expression patterns showed both organ and supplementation protocol dependence. Further analysis indicated that iron levels in the fetal, and not maternal, liver regulate the expression of liver transferrin receptor and hepcidin expression in the mother.
81 citations
TL;DR: Although the bacterial genera and species responsible for biohydrogenation in the rumen and the human intestine differ, and a second route of RA formation via a 10-OH-18 : 1 is present in the intestine, the overall labelling patterns of different CLA isomers formation are common to both gut ecosystems.
Abstract: Faecal bacteria from four human donors and six species of human intestinal bacteria known to metabolize linoleic acid (LA) were incubated with LA in deuterium oxide-enriched medium to investigate the mechanisms of conjugated linoleic acid (CLA) and vaccenic acid (VA) formation. The main CLA products in faecal suspensions, rumenic acid (cis-9,trans-11-CLA; RA) and trans-9,trans-11-CLA, were labelled at C-13, as were other 9,11 geometric isomers. Traces of trans-10,cis-12-CLA formed were labelled to a much lower extent. In pure culture, Bifidobacterium breve NCFB 2258 formed labelled RA and trans-9,trans-11-CLA, while Butyrivibrio fibrisolvens 16.4, Roseburia hominis A2-183T, Roseburia inulinivorans A2-192T and Ruminococcus obeum-like strain A2-162 converted LA to VA, labelled in a manner indicating that VA was formed via C-13-labelled RA. Propionibacterium freudenreichii subsp. shermanii DSM 4902T, a possible probiotic, formed mainly RA with smaller amounts of trans-10,cis-12-CLA and trans-9,trans-11-CLA, labelled the same as in the mixed microbiota. Ricinoleic acid (12-OH-cis-9-18 : 1) did not form CLA in the mixed microbiota, in contrast to CLA formation described for Lactobacillus plantarum. These results were similar to those reported for the mixed microbiota of the rumen. Thus, although the bacterial genera and species responsible for biohydrogenation in the rumen and the human intestine differ, and a second route of RA formation via a 10-OH-18 : 1 is present in the intestine, the overall labelling patterns of different CLA isomers formation are common to both gut ecosystems. A hydrogen-abstraction enzymic mechanism is proposed that may explain the role of a 10-OH-18 : 1 intermediate in 9,11-CLA formation in pure and mixed cultures.
76 citations
TL;DR: The 76% decrease in methane described here, one of the largest reported to date, exceeds the inhibition that might be expected from purely stoichiometric considerations, suggesting an adaptive effect on the rumen microbial community.
70 citations
TL;DR: PBMSC mimic the known activities of stromal cells from other species, including the human, suggesting that they are a valid model for skeletal research.
Abstract: Neonatal pig bone marrow stromal cells (PBMSC) were tested in vivo and in vitro to establish their use as a large-animal model for the study of skeletogenesis. When implanted in diffusion chambers in athymic mice for 6-8 weeks, both freshly isolated pig bone marrow and passage 2 PBMSC formed partially mineralized cartilage, bone-like material, and fibrous tissue. The cartilage showed metachromatic, perilacunar staining with toluidine blue and safronin O, alcian blue staining for chondroitin and keratan sulfate, and intense immunostaining for type II collagen. Osteocalcin was immunolocalized to the mineralized regions, consistent with the formation of bone. Alkaline phosphatase was primarily observed in cell layers at boundaries between tissue types. Unstimulated monolayer cultures of PBMSC produced type I but not type II collagen, responded to dexamethasone (10(-8) M) with a 1.7-fold increase in alkaline phosphatase activity, and were stimulated to divide by basic fibroblast growth factor (1.5-fold; EC50 1 ng/ml). Transforming growth factor beta (TGF-beta) blocked both dexamethasone-induced alkaline phosphatase expression (EC50, 1 ng/ml of TGF-beta) and the mitogenic effects of bFGF (EC50 0.06 ng/ml of TGF-beta). When incubated for 10-14 days in medium containing dexamethasone, beta-glycerophosphate and ascorbate PBMSC formed mineralized nodules. Calcification occurred in the middle of the aggregates and was associated with intensely alkaline phosphatase positive cells and a dense type I collagen-rich matrix. PBMSC also displayed colony-forming unit-fibroblastic activity, with approximately 1 in 80 of the plated cells formed colonies > 128 cells over 14-21 days. PBMSC therefore mimic the known activities of stromal cells from other species, including the human, suggesting that they are a valid model for skeletal research.
63 citations
TL;DR: The sensitivity of growth and fetal development to the lack of zinc is hypothesized to relate to a requirement for the element during certain critical alterations in gene expression, and the evidence for this and possible underlying mechanisms is examined.
Abstract: For many of the genes encoding proteins involved in the transport, storage, and function of the trace elements, expression is regulated by the availability of the elements concerned. This control is exercised through a variety of mechanisms, including metal-activated transcription factors, modified usage of stop codons, and use of secondary structure within mRNA to regulate its translation and stability. Two widely represented groups of transcription factors, often classed as zinc-finger proteins, depend on constituent zinc ions for their activity. In addition, the sensitivity of growth and fetal development to the lack of zinc is hypothesized to relate to a requirement for the element during certain critical alterations in gene expression. The evidence for this and possible underlying mechanisms is examined.
54 citations
TL;DR: Correlation analysis revealed down‐regulation of classical biomarkers of ER stress in their adipose tissue, suggesting that disruption of the IL‐1RI‐mediated inflammatory response may attenuate cellular stress, which was associated with significant protection from diet‐induced insulin resistance, independent of obesity.
Abstract: The development of insulin resistance in the obese is associated with chronic, low-grade inflammation. We aimed to identify novel links between obesity, insulin resistance and the inflammatory response by comparing C57BL/6 with type I interleukin-1 receptor knockout (IL-1RI(-/-)) mice, which are protected against diet-induced insulin resistance. Mice were fed a high-fat diet for 16 wk. Insulin sensitivity was measured and proteomic analysis was performed on adipose, hepatic and skeletal muscle tissues. Despite an equal weight gain, IL-1RI(-/-) mice had lower plasma glucose, insulin and triacylglycerol concentrations, compared with controls, following dietary treatment. The higher insulin sensitivity in IL-1RI(-/-) mice was associated with down-regulation of antioxidant proteins and proteasomes in adipose tissue and hepatic soluble epoxide hydrolase, consistent with a compromised inflammatory response as well as increased glycolysis and decreased fatty acid beta-oxidation in their muscle. Their lower hepatic triacylglycerol concentrations may reflect decreased flux of free fatty acids to the liver, decreased hepatic fatty acid-binding protein expression and decreased lipogenesis. Correlation analysis revealed down-regulation of classical biomarkers of ER stress in their adipose tissue, suggesting that disruption of the IL-1RI-mediated inflammatory response may attenuate cellular stress, which was associated with significant protection from diet-induced insulin resistance, independent of obesity.
TL;DR: Results indicate that PAP may be effective in controlling acidosis of heifers during a rapid transition to a high-concentrate diet and the fermentation profile of animals with acidosis was similar between treatments.
Abstract: Physiological changes in rumen fermentation during acidosis induction and its control using a multivalent polyclonal antibody preparation (PAP) were studied in a completely randomized experiment using 12 crossbred heifers (452 +/- 20 kg of BW). Treatments were control (CTR) or PAP. The acidosis induction protocol consisted of 3 periods: 3 mo of 100% fescue hay fed for ad libitum intake, 10 d (from d 1 to 10 of the experiment) of adaptation to the treatment (100% forage feeding + 10 mL/d of PAP top-dressed to the treatment group), and 5 d (from d 11 to 15 of the experiment) of transition, which consisted of increasing the concentrate (16.5% CP) 2.5 kg/d up to 12.5 kg/d while maintaining ad libitum intake of fescue and providing 10 mL/d of PAP to the treated heifers. Concentrate feeding of 12.5 kg/d was maintained until heifers developed acidosis (from d 16 to 22 of the experiment). When an animal was considered acidotic, it was changed to a 50:50 forage:concentrate diet, monitored for 4 d, and removed from the experiment. Samples of ruminal fluid were collected before and 6 h after feeding to determine pH, VFA, lactate, protozoa counts, and DNA extraction for quantitative real-time PCR and denaturing gradient gel electrophoresis analyses. Only samples collected during adaptation to the treatment, at 3 and 1 d before acidosis, on the acidosis day, and at 1 and 4 d after acidosis were analyzed. Differences were declared at P < 0.05. Heifers (83% for CTR, and 50% for PAP) entered into acidosis 5.25 +/- 0.17 d after the beginning of the transition. The fermentation profile of animals with acidosis was similar between treatments. From 3 d before acidosis to acidosis day, decreases in pH and in acetate-to-propionate ratio and increases in total VFA, butyrate, and entodiniomorph counts were observed. However, the greatest concentrations of Streptococcus bovis and Megasphaera elsdenii (79 +/- 54 and 104 +/- 73 ng of DNA/mL of ruminal fluid, respectively) and a decrease in DMI (10.6 vs. 6.46 kg, respectively) were recorded 1 d after acidosis. Compared with CTR heifers, heifers fed PAP had greater pH before feeding on d 6 (6.70 vs. 6.11), 8 (6.54 vs. 5.95), and 9 (7.26 vs. 6.59) after the beginning of the feeding challenge. Heifers fed PAP tended to have greater total VFA concentrations than CTR (124 and 114 +/- 4.0 mM, respectively). These results indicate that PAP may be effective in controlling acidosis of heifers during a rapid transition to a high-concentrate diet.
TL;DR: The CLA formed in the intestine of different individuals may differ according to their resident microbiota, with possibly important implications with respect to gut health.
Abstract: Conjugated linoleic acid (CLA) is formed from linoleic acid (LA; cis-9,cis-12-18:2) by intestinal bacteria. Different CLA isomers have different implications for human health. The aim of this study was to investigate LA metabolism and the CLA isomers formed in two individuals (V1 and V2) with different faecal metabolic characteristics, and to compare fatty acid metabolism with the microbial community composition. LA incubated with faecal samples was metabolized at similar rates with both subjects, but the products were different. LA was metabolized extensively to stearic acid (SA; 18:0) in V1, with minor accumulation of CLA and more rapid accumulation of vaccenic acid (VA; trans-11-18:1). CLA accumulation at 4 h was almost tenfold higher with V2, and little SA was formed. At least 12 different isomers of CLA were produced from LA by the colonic bacteria from the two individuals. The predominant (>75%) CLA isomer in V1 was rumenic acid (RA; cis-9,trans-11-18:2), whereas the concentrations of RA and trans-10,cis-12-18:2 were similar with V2. Propionate and butyrate proportions in short-chain fatty acids were higher in V1. A 16S rRNA clone library from V1 contained mainly Bacteroidetes (54% of clones), whereas Firmicutes (66% of clones) predominated in V2. Both samples were devoid of bacteria related to Clostridium proteoclasticum, the only gut bacterium known to metabolize VA to SA. Thus, the CLA formed in the intestine of different individuals may differ according to their resident microbiota, with possibly important implications with respect to gut health.
TL;DR: The World Health Organization (WHO) has proposed body mass index (BMI) as a simple measure of obesity as discussed by the authors, but it should be remembered that calculation of a raised BMI does not automatically indicate a high degree of adiposity.
Abstract: It is important to establish what the medical view of obesity should be. An important step is the development of a standardised definition of obesity. The World Health Organisation (WHO) has proposed body mass index (BMI) as a simple measure of obesity. Whereas BMI has great clinical utility, it should be remembered that calculation of a raised BMI does not automatically indicate a high degree of adiposity. This is because BMI does not distinguish between weight due to excess fat, and weight due to a large mass of muscle or bone. Gender and age also have to be considered when evaluating BMI measurements. Obesity is related to many disorders, most of which are metabolic in origin. For example, hypertension and the adverse lipid profile associated with obesity increases the risk of coronary heart disease (CHD). There is also a profound association between obesity, particularly intra-abdominal adiposity, and the development of non-insulin dependent diabetes mellitus (NIDDM). Obesity has reached epidemic proportions. This is paralleled by an increasing incidence of NIDDM. There is no doubt that weight gain and obesity are major clinical problems, which need to be prevented and managed more effectively. This is essential, given the role of obesity in many of the chronic health problems affecting westernised societies.
TL;DR: The results suggest that 1,25‐(OH)2D3 in vivo does not increase the rate of chondrocyte prolferation but accelerates the onset of maturation.
Abstract: A combination of immunocytochemistry and in situ biochemistry has been used to determine the in vivo effects of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] on the proliferation and differentiation of chondrocytes. Chicks were fed a diet supplemented with 1,25-(OH)2D3 (2.5, 5, or 10 micrograms/kg diet) for 3 weeks, and measurements were made in sections of growth plate of chondrocyte proliferation and rate of maturation through the growth plate [using bromodeoxyuridine (BrdUrd) labeling] and also chondrocyte differentiation [assessed by alkaline phosphatase (ALP) activity]. The labeling indices of the control and supplemented chicks were similar (23.1 +/- 1.3 versus 23.2 +/- 1.6%); however, within a 21 h period the BrdUrd-positive cells of the supplemented chicks had moved down the growth plate significantly farther than in the control chicks (71.0 +/- 2.8 versus 52.6 +/- 1.8%). Greater ALP (mean integrated absorbance) activity higher up the growth plate of the supplemented chicks indicated a more differentiated phenotype in cells closer to the epiphyseal junction. Within individual transitional chondrocytes ALP activity in the 10 micrograms/kg supplemented chicks was 26.6 +/- 0.85, which was significantly higher (p < 0.01) than that of the control chicks (19.2 +/- 0.9). These results suggest that 1,25-(OH)2D3 in vivo does not increase the rate of chondrocyte proliferation but accelerates the onset of maturation.
TL;DR: Data indicated that intestinal mass as a proportion of maternal BW declined in overnourished, gestating ewe lambs and was more pronounced during late gestation and is likely explained by the increasing maternal BW and adiposity rather than by the changing cellularity or cell proliferation.
Abstract: Peripubertal ewe lambs (44.3 +/- 1.1 kg of initial BW) were used in a 2 x 3 factorial design to test the effects of plane of nutrition (diet) and stage of gestation on maternal visceral tissue mass, intestinal cellularity, crypt cell proliferation, and jejunal mucosal vascularity. Singleton pregnancies to a single sire were established by embryo transfer, and thereafter ewes were offered a control (Control) or high (High) amount of a complete diet (2.84 Mcal/kg and 15.9% CP; DM basis) to promote slow or rapid maternal growth rates. After d 90 of gestation, feed intake of the Control group was adjusted weekly to maintain BCS and meet the increasing nutrient demands of the gravid uterus. Ewes were slaughtered at 50 d (n = 6 Control; n = 5 High), 90 d (n = 8 Control; n = 6 High), or 130 d (n = 8 Control; n = 6 High) of gestation. Ewes were eviscerated and masses of individual organs were recorded. The jejunum was sampled and processed for subsequent analyses. Final ewe BW for Control-fed ewes was similar at d 50 and 90 and increased (P = 0.10) from d 90 to 130 (46.0, 48.9, and 58.2 +/- 1.6 kg, respectively), whereas final BW increased (P
TL;DR: Data suggest that engulfment of chloroplasts is a major contributor to the high 18:3 (n-3) concentration of protozoa, and that Epidinium spp.
TL;DR: The results do not support beneficial effects of CLA/n-3 LC-PUFA for β-cell dysfunction or insulin resistance in humans but suggest that insulin sensitivity in older obese subjects is reduced.
Abstract: Dietary addition of either conjugated linoleic acid (CLA) or n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) has been shown to alter adiposity and circulating lipids, risk markers of cardiovascular diseases. However, CLA may decrease insulin sensitivity, an effect that may be reversed by n-3 LC-PUFA. Thus, the potential of CLA plus n-3 LC-PUFA to affect insulin secretion and sensitivity in non-diabetic young and old, lean and obese subjects was tested. CLA (3 g daily) plus n-3 LC-PUFA (3 g daily) or control oil (6 g daily) was given to lean (n=12; BMI 20–26 kg/m2) or obese (n=10; BMI 29–35 kg/m2) young (20–37 years old) or lean (n=16) or obese (n=11) older men (50–65 years) for 12 weeks. The study had a double-blind, placebo-controlled randomized crossover design, and primary end points were insulin secretion and sensitivity during a standardized meal test, evaluated by modeling glucose, insulin and C-peptide data. The combination was well tolerated. There was no significant difference in fasting levels of glucose, insulin or C-peptide after CLA/n-3 LC-PUFA treatment compared with control oil. Neither insulin secretion nor estimated sensitivity was affected by CLA/n-3 LC-PUFA in lean or obese young subjects or in older lean subjects. However, in older obese subjects, estimated insulin sensitivity was reduced with CLA/n-3 LC-PUFA compared with control (P=0.024). The results do not support beneficial effects of CLA/n-3 LC-PUFA for β-cell dysfunction or insulin resistance in humans but suggest that insulin sensitivity in older obese subjects is reduced.
TL;DR: Results indicate that GH stimulates the commitment of chondrocytes within the resting/germinal layer to a proliferative phenotype but only in the presence of other pituitary hormones, and shows that enzyme activities within single chond rocytes and osteoclasts are GH‐sensitive.
Abstract: Longitudinal growth is a result of proliferation and differentiation of chondrocytes in the growth plate. Growth hormone (GH) stimulates longitudinal growth, and GH receptors have been shown on growth plate chondrocytes, but the effects of GH on chondrocytes of different cell layers are not clear. To study the effect of GH on chondrocyte activity, in situ biochemical techniques were used to measure enzyme activities, which are associated with cell differentiation (alkaline phosphatase [ALP]) and osteoclast activity (tartrate-resistant acid phosphatase [TRAP]), within single cells of the growth plate. Uptake of bromodeoxyuridine (BrdU) was used as a parameter for proliferative activity. In addition, glucose-6-phosphate dehydrogenase (G6PD) was measured since increased proliferation has been associated with increased G6PD activity. The role of GH was studied in a model of isolated GH deficiency (dwarf rat) and complete pituitary deficiency (hypophysectomized rat). Groups of GH-deficient dwarf rats were infused with recombinant human GH in either a continuous or a pulsatile manner, since the pattern of GH secretion is an important regulator of growth in the rat. After 7 days, G6PD activity in proliferative chondrocytes and TRAP activity in osteoclasts was increased, while ALP activity in hypertrophic chondrocytes was decreased. GH not only increased the number of chondrocytes that incorporated BrdU but also the total number of chondrocytes in the proliferative zone; therefore, its ratio, the labeling index (an indicator of proliferative rate), was not increased. The widths of the proliferative and hypertrophic zones were increased by both patterns of GH administration. The width of the resting zone was unaffected by continuous GH but decreased by pulsatile GH. ALP and TRAP activities were, respectively, higher and lower in hypophysectomized rats compared with the GH-deficient animals. Hypophysectomized rats had smaller growth plates than dwarf rats with a disproportionally wide resting zone, which, like BrdU uptake, was not affected by GH. GH treatment resulted in increased TRAP and decreased ALP activity. These results indicate that GH stimulates the commitment of chondrocytes within the resting/germinal layer to a proliferative phenotype (as opposed to stimulating the rate of chondrocyte proliferation) but only in the presence of other pituitary hormones. Furthermore, this study shows that enzyme activities within single chondrocytes and osteoclasts are GH-sensitive. The extent to which these effects are direct or mediated by systemic or local growth factors remains to be clarified.
TL;DR: The results suggest that folate deficiency during gestation causes modest changes to the insulin axis of the fetus, and this affects the growth, blood pressure and insulin action in the offspring.
Abstract: In humans poor maternal folate status is associated with a decrease in infant birth weight. As low birth weight increases the risk of cardiovascular and metabolic disease in adults, an inadequate supply of folic acid in the mother's diet may increase the susceptibility of the offspring to disease. We have fed laboratory rats diets deficient in folic acid and the related methyl donors methionine and choline to examine the effects on growth, blood pressure and insulin action in the offspring. Poor folate status transiently increased fetal growth but did not produce a long-term change in body weight. There were, however, small changes in the hearts of the female offspring. When folate deficiency was combined with low intakes of methionine and choline, the kidneys of the male offspring were proportionately smaller, probably because of the limited availability of methionine. There was no effect on the blood pressure of either the male or female offspring. The pancreatic insulin content of fetuses from animals fed the folate-deficient diets were higher than those of the controls. Following an oral glucose challenge, there was a weak trend for glucose-stimulated insulin release to be increased in the offspring of dams fed the folate-deficient diet. The changes in insulin concentrations were, however, much smaller than the corresponding changes observed in the offspring of animals fed protein-deficient diets. These results suggest that folate deficiency during gestation causes modest changes to the insulin axis of the fetus.
TL;DR: A physiological role for EMMPRIN other than MMP induction in mammary gland biology is supported, as its expression decreases during early pregnancy and briefly after induction of mammary glands involution by litter removal.
Abstract: Extracellular matrix metalloproteinase inducer (EMMPRIN/basigin/CD147) is a cell surface protein, which has been associated with the induction of matrix metalloproteinase (MMP) genes during cancer metastasis. EMMPRIN plays a role in a variety of physiological processes as is evident by the diverse deficiencies detectable in EMMPRIN knockout mice. We have analysed the role of EMMPRIN in the induction of MMP genes during mammary gland differentiation and involution. Co-transfection studies showed that EMMPRIN has diverse effects on MMP promoter activity in different mammary and non-mammary cell lines. Expression of EMMPRIN mRNA is enhanced markedly by insulin in a mammary gland cell line but appears to have no direct effect on MMP gene expression in these cells. Microarray analysis and quantitative PCR show that EMMPRIN is expressed throughout mammary gland differentiation in the mouse. Its expression decreases during early pregnancy and briefly after induction of mammary gland involution by litter removal. Immunohistochemical analysis shows that EMMPRIN expression is limited to the stromal compartment during pregnancy, whereas it is strongly expressed in the epithelium during lactation. In summary the data argue against a causal role for EMMPRIN for the induction of MMP gene expression during adult mammary gland development. These data therefore support a physiological role for EMMPRIN other than MMP induction in mammary gland biology.
TL;DR: This study identified several photoperiodically regulated genes in the dmpARC that are known to have roles in secretory and intracellular signalling pathways, including secretogranin (sg) III and SgVI (secretory pathway), melanocortin 3 receptor (MC3‐R) and serotonin (5‐HT) receptors 2A and 7 (signalling pathway), all of which increase in expression under a short Photoperiod.
Abstract: The mechanism(s) involved in the regulation of the seasonal-appropriate body weight of the Siberian hamster are currently unknown. We have identified photoperiodically regulated genes including VGF in a sub-region of the arcuate nucleus termed the dorsomedial posterior arcuate (dmpARC). Gene expression changes in this nucleus so far account for a significant number of those reported as photoperiodically regulated and are therefore likely to contribute to seasonal physiological responses of the hamsters. The present study aimed to identify additional genes expressed in the dmpARC regulated by photoperiod that could be involved in regulating the activity of this nucleus with respect to seasonal physiology of the Siberian hamster. Using laser capture microdissection coupled with a microarray analysis and a candidate gene approach, we have identified several photoperiodically regulated genes in the dmpARC that are known to have roles in secretory and intracellular signalling pathways. These include secretogranin (sg) III and SgVI (secretory pathway), melanocortin 3 receptor (MC3-R) and serotonin (5-HT) receptors 2A and 7 (signalling pathway), all of which increase in expression under a short photoperiod. The spatial relationship between receptor signalling and potential secretory pathways was investigated by dual in situ hybridisation, which revealed that 5-HT2A and 5-HT7 receptors are expressed in neurones expressing VGF mRNA and that a sub-population (approximately 40%) of these neurones express MC3-R. These gene expression changes in dmpARC neurones may reflect the functional requirement of these neurones for seasonal physiological responses of the hamster.
TL;DR: In this article, a comparison of the intramolecular Sn O bond lengths in solid 1 (X = Cl, Br or I) indicates that the strength of the Sn O interaction increases in the order X = I O bond is greater in Cl3SnCH2CH2CO2Me than in the corresponding ketotin compound, Cl3snCMe2CCH2COMe, another chelated complex.
01 Jan 2009
TL;DR: This chapter focuses upon the influence of diet composition upon the metabolic activities and species composition of the human colonic microbiota.
Abstract: Microbial colonization of the human intestine has multiple consequences. On the negative side, the gut is a source of pathogens and inflammation, and microbial activity can produce toxic metabolites. On the positive side, the gut community in healthy individuals helps to create a barrier that reduces the risk of infection by pathogens, while the major products of microbial fermentation in the colon, the short chain fatty acids, especially butyrate, play a generally beneficial role in maintaining gut health. This chapter focuses upon the influence of diet composition upon the metabolic activities and species composition of the human colonic microbiota.
TL;DR: It is suggested that the potentiation of the response to PTH occurs after only 8 minutes and represents a nongenomic response to the vitamin D3 metabolites.
Abstract: With the development of a sensitive bioassay for the skeletal effects of parathyroid hormone (PTH), it has become possible to investigate the possible interaction between PTH and vitamin D3 metabolites. This assay is based on the stimulation of glucose-6-phosphate dehydrogenase (G6PD) activity in either the hypertrophic chondrocytes of the growth plate or the osteoblasts lining the metaphyseal trabeculae of rat metatarsals. The response to PTH is paralleled by the activity of dibutyryl cAMP. None of the vitamin D3 metabolites tested had any effect on enzyme activity when tested by themselves. However, both 1,25(OH)2D3 and 25(OH)D3 caused a dose-related potentiation of the response to PTH. Neither 1,24,25(OH)3D3 nor 1,25(OH)2D3 26,23-lactone potentiated the response to PTH. Because this potentiation of the response to PTH occurs after only 8 minutes, it is suggested that it represents a nongenomic response to the vitamin D3 metabolites.