21 research outputs found
A Creatine Transporter Is Operative at the Brush Border Level of the Rat Jejunal Enterocyte
Abstract
Although ergogenic effects and health benefits have been reported for creatine used as nutritional supplement, to date little is known about the mechanism of creatine absorption in the small intestine. Thus the current study was undertaken to elucidate the mechanism of creatine intake in rat jejunum with the use of well-purified brush border membrane vesicles, isolated from jejunal enterocyte. Creatine uptake was found markedly stimulated by inwardly directed Na(+) and Cl(- )gradients, potential-sensitive, strongly reduced by the substitution of Na(+) and Cl(-) with various cations and anions and positively affected by intravesicular K(+). Moreover, creatine uptake is: 1) significantly inhibited by creatine structural analogs, 2) abolished by low concentrations of 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA), 3) saturable as a function of creatine concentration with an apparent Michaelis-Menten constant of 24.08 +/- 0.80 muM and a maximal velocity of 391.30 +/- 6.19 pmoles mg protein(-1) 30 s(-1). The transport is electrogenic since at least two Na(+) and one Cl(-) are required to transport one creatine molecule. Western blot analysis showed the same amount of creatine transport protein in the jejunal apical membrane when compared to ileum. Thus, these data demonstrate the existence of a Na(+)- and Cl(-)-dependent, membrane potential-sensitive, electrogenic carrier-mediated mechanism for creatine absorption in rat jejunal apical membrane vesicles, which is biochemically and pharmacologically similar to those observed in other tissues. However, in other cell types the stimulatory effect of intravesicular K(+) was never detected
Testing seed germination from herbaria: Application of seed quality enhancement techniques and implication for plant resurrection and conservation
Herbaria are an important source of data and material useful in many fields, including plant conservation. Seeds preserved in herbarium specimens may have the potential to germinate, although few studies focused on this topic. Here, the first systematic assessment of six techniques, including priming techniques and melatonin application, aimed at improving the germination of seeds from herbarium specimens is presented. Seed germination of 26 species common in Europe, some of which congeneric to extinct species, collected in herbaria and in the wild (20,549 seeds in total, including 19,509 from 297 herbarium specimens from 8 different herbaria) was tested with the following treatments: exogenous melatonin addition to the germination medium, priming with melatonin, osmopriming, hydropriming for 24 and 48 hours, standard soil, heat sterilization and gibberellins addition. More than 85% of the fresh seeds and 1% of the seeds collected in herbaria germinated, including seeds older than 50 years. Data show that treatment with exogenous melatonin had a positive effect on the germination of fresh seeds, but a negative effect on the germination of herbarium-derived seeds. Furthermore, osmopriming treatment had a slightly positive effect on the germination of herbarium-derived seeds. Osmopriming and exogenous melatonin addition seem to be promising techniques that need further investigation and improvement and might be useful for the development of an optimal germination protocol for old and herbarium-derived seeds. The germination of seeds from herbaria could be an important tool in plant conservation, with the aim of reversing the extinction trend of many species through de-extinction, safeguarding biodiversity, and genetic variability. This study provides preliminary data for the development of germination protocols, especially for old seeds of species of conservation interest, to maximise the chance of recovering lost genetic diversity and leading to the first de-extinction ever
Clinicopathological Factors Influencing Lymph Node Yield in Colorectal Cancer: A Retrospective Study
Many colorectal resections do not meet the minimum of 12 lymph nodes (LNs) recommended by the American Joint Committee on Cancer for accurate staging of colorectal cancer. The aim of this study was to investigate factors affecting the number of the adequate nodal yield in colorectal specimens subject to routine pathological assessment. We have retrospectively analysed the data of 2319 curatively resected colorectal cancer patients in San Raffaele Scientific Institute, Milan, between 1993 and 2017 (1259 colon cancer patients and 675 rectal cancer patients plus 385 rectal cancer patients who underwent neoadjuvant therapy). The factors influencing lymph node retrieval were subjected to uni- and multivariate analyses. Moreover, a survival analysis was carried out to verify the prognostic implications of nodal counts. The mean number of evaluated nodes was 24.08±11.4, 20.34±11.8, and 15.33±9.64 in surgically treated right-sided colon cancer, left-sided colon cancer, and rectal tumors, respectively. More than 12 lymph nodes were reported in surgical specimens in 1094 (86.9%) cases in the colon cohort and in 425 (63%) cases in the rectal cohort, and patients who underwent neoadjuvant chemoradiation were analysed separately. On univariate analysis of the colon cancer group, higher LNs counts were associated with female sex, right colon cancer, emergency surgery, pT3-T4 diseases, higher tumor size, and resected specimen length. On multivariate analysis right colon tumors, larger mean size of tumor, length of specimen, pT3-T4 disease, and female sex were found to significantly affect lymph node retrieval. Colon cancer patients with 12 or more lymph nodes removed had a significantly better long-term survival than those with 11 or fewer nodes (P=0.002, log-rank test). Rectal cancer patients with 12 or more lymph nodes removed approached but did not reach a statistically different survival (P=0.055, log-rank test). Multiple tumor and patients’ factors are associated with lymph node yield, but only the removal of at least 12 lymph nodes will reliably determine lymph node status
Age at Onset and Social Cognitive Impairment in Clinically Stabilized Patients with Schizophrenia: An Ecological Cross-Sectional Study
Objective: Purposes of the present study were to assess the social cognitive impairment in schizophrenia and to detect if some clinical variables (particularly age at onset) are predictive of general/social cognitive deficit in schizophrenia patients.
Method: Thirty-five clinically stabilized schizophrenia outpatients were assessed by the Brief Assessment of Cognition in Schizophrenia (BACS) and by Torralva’s social cognition battery. Binary logistic models were performed to find an eventual association between continuous clinical variables and cognitive test failures. The total sample was divided in groups according to dichotomous variables (gender, diagnostic subtypes and type of abuse) and the presence of cognitive deficits was compared between groups by χ2 tests.
Results: An earlier age at onset was found to be predictive of frontal cognitive impairment (Tower of London p=0.038, OR=0.702). Female gender was more probably associated with mistakes at MET-HV (χ2= 4.80, p=0.05, phi=0.40) and HOTEL tests (χ2= 5.25, p=0.04, phi=0.4) than male one. Cannabis abusers showed more frequently deficits on verbal fluency (χ2= 9.35, p=0.04, phi=0.52) and executive functioning (Tower of London) (χ2= 11.67, p=0.02, phi=0.58) than alcohol/cocaine ones.
Conclusion: Female patients with an early age at onset and cannabis abuse seem to have the worst general and social cognitive profile among patients suffering from schizophreni
Protein Kinase C Regulation of Rat Jejunal Transport Systems: Mechanisms Involved in Lactate Movement
Litter decomposition: effects of temperature driven by soil moisture and vegetation type
Aims
We examined the importance of litter quality and microclimate on early-stage litter mass loss, analysed the importance of interactions among environmental factors in determining key decomposition parameters and compared the variation in decomposition rates in vegetation types and sites with similar climate.
Methods
Following the Tea-Bag Index approach, 464 tea-bags were incubated in the soil in 79 sites, distributed across Italy, which included six vegetation types and a broad range of microclimatic conditions.
Results
Litter type exerted a stronger control on mass loss compared to climatic factors. The effects of soil moisture were not the same for high and lower quality litter. In addition, the effects of temperature on the decomposition rate depended on soil moisture. The stabilization factor was strongly temperature-dependent, but the influence of temperature differed among vegetation types: those dominated by small-size plants showed a strong decrease in the potential amount of plant material entering into the soil stock under warmer temperatures. The lowest variation in decomposition rate was found in sites characterised by low temperatures, and, among the vegetation types, in alpine snowbeds.
Conclusions
The role of litter quality and of the interactions among environmental conditions can potentially determine significant shifts in the expected patterns of ecosystem carbon fluxes
Global and Regional IUCN Red List Assessments: 15
In this contribution, the conservation status assessment of three vascular plants are presented according to IUCN categories and criteria. It includes the assessment of Oryza rhizomatis D.A.Vaughan and Saxifraga facchinii W.D.J.Koch at a global level and Helianthemum caput-felis Boiss. at a regional level
PYY-Tag transgenic mice displaying abnormal (H+-K+)ATPase activity and gastric mucosal barrier impairment
The mechanism by which the gastrointestinal hormones peptide YY and glucagon inhibit gastric acid secretion is largely unknown. PYY-Tag transgenic mice develop endocrine tumors in the colon that are composed mainly of peptide YY/enteroglucagon-producing L type cells. Therefore we studied the functional activity of such tumors and the gastric functions of PYY-Tag mice. Fasting and fed PYY-Tag transgenic mice and CD1 controls were assayed for circulating levels of peptide YY, glucagon, insulin, and gastrin. The gastric pH was determined and gastric samples were examined for (a) histologic appearance; (b) K(+)-stimulated p-nitrophenylphosphatase activity and [(14)C]aminopyrine accumulation of apical and tubulovesicle membranes; (c) adherent mucus determination by Alcian blue recovery; and (d) DNA/RNA/protein epithelial content and in vivo incorporation of [(3)H]thymidine into DNA. Transgenic mice showed high serum levels of peptide YY and glucagon, increased gastric pH, and a high incidence of gastric ulcers after fasting. p-Nitrophenylphosphatase activity, [(14)C] aminopyrine accumulation, and proton pump redistribution from cytoplasmic tubulovesicles to apical membranes were significantly lower in the gastric mucosa of transgenic mice compared with the controls. In addition, the adherent mucus was thinner, and [(3)H]thymidine incorporation into the DNA was decreased. The abnormal and unregulated levels of circulating peptide YY and glucagon led to gastric acid inhibition and an impairment of gastric barrier function as a result of a striking reduction in epithelial proliferation
A pragmatic and prudent consensus on the resurrection of extinct plant species using herbarium specimens
Abstract Herbaria may represent remarkable sources of viable diaspores for recovering lost genetic variation and extinct plant species, but the application of rewilding extinct species using these collections has not been explored in detail. De-extinction in plants may be achieved by germinating viable diaspores or culturing tissues preserved in herbarium specimens. Germination of old diaspores (fruits, seeds, spores) preserved in sub-optimal uncontrolled storage conditions demonstrates that the recovery of extinct plants from herbarium specimens may be possible. Plant de-extinction via herbarium specimens relies on the availability of samples containing viable diaspores, and on the inclination of curators and the conservation community to use such material for this purpose. We developed an internet-based survey to assess (i) whether the scientific community would consent to the use of herbarium specimens of extinct species to attempt de-extinction, and (ii) the limitations of removing diaspores from specimens. Despite the risk of potential damages to valuable specimens from historical collections when harvesting diaspores, a consensus for using specimens of extinct plant species emerged. Most respondents would permit the collection of a low number of diaspores, preferably from duplicate specimens and only if the integrity of the specimen is preserved. These considerations would be more restrictive for type specimens and those of historical value. These results help to formalise a decision framework for the grant and use of material from natural history collections and a pragmatic approach to attempt to resurrect extinct species from herbarium specimens