182 research outputs found
Photosynthates : mainly stored and yet limiting in propagation of rose cuttings.
Leaves are essential in the propagation of roses by cuttings. However, about the underlying principles, there is no unequivocal opinion in the literature. We investigated the hypothesis that current photosynthesis would represent the dominating factor. To validate this hypothesis variations in photosynthesis were created by reducing leaf area, covering of leaves and by reducing CO2 air concentration. The consequences in terms of survival percentage, root formation, and carbohydrate concentrations were followed throughout the first 3 weeks of propagation. Moreover, the known promoting effect of auxins was studied in a comparative experiment to investigate potential auxin deficiencies created by the leaf treatments. Leaf removal, leaf covering or CO2 depletion had a quantitative negative effect on survival and growth of cuttings. Auxins did not promote rooting when leaves were covered or removed. Dry matter distributed uniformly by the leaf and stem of cuttings after 21 days of propagation. Unexpected, and perhaps contradictory, was that, although current leaf photosynthesis seemed the limiting factor for propagation, the majority of photosynthates was stored as starch. This apparent ineffective use of photosynthates could be explained in terms of competition within different sinks. The weak sink of starch accumulating organelles becomes the major sink relatively to the modest sink activity of the new roots and new shoots. In fact, the new formed organs accounted for less than 15␘f the total dry weight of cuttings. It is concluded that photosynthetic capacity of cuttings is to be considered an important determinant for quality in rose propagation. Further research should confirm the relationship between photosynthesis and its value as criterion for quality in rose propagation
Somatostatin does not attenuate intestinal injury in dextran sodium sulphate-induced subacute colitis.
FRom several in vitro and in vivo studies involvement of somatostatin (SMS) in intestinal inflammation emerge. Acute colitis induced in rats is attenuated by the long-acting SMS analogue octreotide. We studied the potential beneficial effect of SMS on non-acute experimental colitis. BALB/c mice received either saline, SMS-14 (36 or 120 microg daily) or octreotide (3 microg daily) subcutaneously delivered by implant osmotic pumps. A non-acute colitis was induced by administration of dextran sodium sulphate (DSS) 10% in drinking water during 7 days. DSS evoked a mild, superficial pancolitis, most characterized by mucosal ulceration and submucosal influx of neutrophils. Neither SMS-14 nor octreotide reduced mucosal inflammatory score or macroscopical disease activity, although reduction of intestinal levels of interleukin-1beta (IL-1beta), IL-6 and IL-10 during DSS was augmented both by SMS and octreotide. A slight increase of neutrophil influx was seen during SMS administration in animals not exposed to DSS. In conclusion, SMS or its long-acting analogue did not reduce intestinal inflammation in non-acute DSS-induced colitis. According to the cytokine profile observed, SMS-14 and octreotide further diminished the reduction of intestinal macrophage and Th2 lymphocyte activity
Body mass index at diagnosis of a childhood brain tumor; a reflection of hypothalamic-pituitary dysfunction or lifestyle?
Purpose: Childhood brain tumor survivors (CBTS) are at risk of becoming overweight, which has been shown to be associated with hypothalamic-pituitary (HP) dysfunction during follow-up. Body mass index (BMI) at diagnosis is related to BMI at follow-up. It is uncertain, however, whether aberrant BMI at brain tumor diagnosis reflects early hypothalamic dysfunction or rather reflects genetic and sociodemographic characteristics. We aimed to examine whether BMI at childhood brain tumor diagnosis is associated with HP dysfunction at diagnosis or its development during follow-up. Methods: The association of BMI at diagnosis of a childhood brain tumor to HP dysfunction at diagnosis or during follow-up was examined in a Dutch cohort of 685 CBTS, excluding children with craniopharyngioma or a pituitary tumor. Individual patient data were retrospectively extracted from patient charts. Results: Of 685 CTBS, 4.7% were underweight, 14.2% were overweight, and 3.8% were obese at diagnosis. Being overweight or obese at diagnosis was not associated with anterior pituitary deficiency or diabetes insipidus at diagnosis or during follow-up. In children with suprasellar tumors, being obese at diagnosis was associated with central precocious puberty. Conclusion: Overweight or obesity at diagnosis of a childhood brain tumor seems not to be associated with pituitary deficiencies. These results suggest that genetics and lifestyle may be more important etiologic factors for higher BMI at diagnosis in these children than hypothalamic dysfunction. To improve the long-term outcome of CBTS with regards to overweight and obesity, more attention should be given to lifestyle already at the time of brain tumor treatment
Functional health status in subjects after a motor vehicle accident, with emphasis on whiplash associated disorders: design of a descriptive, prospective inception cohort study
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70254.pdf (publisher's version ) (Open Access)BACKGROUND: The clinical consequences of whiplash injuries resulting from a motor vehicle accident (MVA) are poorly understood. Thereby, there is general lack of research on the development of disability in patients with acute and chronic Whiplash Associated Disorders. METHODS/DESIGN: The objective is to describe the design of an inception cohort study with a 1-year follow-up to determine risk factors for the development of symptoms after a low-impact motor vehicle accident, the prognosis of chronic disability, and costs. Victims of a low-impact motor vehicle accident will be eligible for participation. Participants with a Neck Disability Index (NDI) score of 7 or more will be classified as experiencing post-traumatic neck pain and will enter the experimental group. Participants without complaints (a NDI score less than 7) will enter the reference group. The cohort will be followed up by means of postal questionnaires and physical examinations at baseline, 3 months, 6 months, and 12 months. Recovery from whiplash-associated disorders will be measured in terms of perceived functional health, and employment status (return to work). Life tables will be generated to determine the 1-year prognosis of whiplash-associated disorders, and risk factors and prognostic factors will be assessed using multiple logistic regression analysis. DISCUSSION: Little is known about the development of symptoms and chronic disability after a whiplash injury. In the clinical setting, it is important to identify those people who are at risk of developing chronic symptoms.This inception prospective cohort study will provide insight in the influence of risk factors, of the development of functional health problems, and costs in people with whiplash-associated disorders
Beyond the ‘Migrant Network’? Exploring assistance received in the migration of brazilians to Portugal and the Netherlands
This paper explores the tenability of three important critiques to the ‘migrant
network’ approach in migration studies: (1) the narrow focus on kin and community
members, which connect prospective migrants in origin countries with immigrants in
the destination areas, failing to take due account of sources of assistance beyond the
‘migrant network’ like institutional or online sources; (2) that it is misleading to assume
a general pattern in the role of migrant networks in migration, regardless of contexts of
arrival or departure, including the scale and history of migration or the immigration
regime; and (3) that ‘migrant networks’ are not equally relevant to all migrants, and that
important differences may exist between labour migrants and other types of migrants
like family migrants or students. Drawing on survey data on the migration of Brazilians
to Portugal and the Netherlands we find support for these critiques but also reaffirm the
relevance of ‘migrant networks’.info:eu-repo/semantics/publishedVersio
Triterpenoid modulation of IL-17 and Nrf-2 expression ameliorates neuroinflammation and promotes remyelination in autoimmune encephalomyelitis
Inflammatory cytokines and endogenous anti-oxidants are variables affecting disease progression in multiple sclerosis (MS). Here we demonstrate the dual capacity of triterpenoids to simultaneously repress production of IL-17 and other pro-inflammatory mediators while exerting neuroprotective effects directly through Nrf2-dependent induction of anti-oxidant genes. Derivatives of the natural triterpene oleanolic acid, namely CDDO-trifluoroethyl-amide (CDDO-TFEA), completely suppressed disease in a murine model of MS, experimental autoimmune encephalomyelitis (EAE), by inhibiting Th1 and Th17 mRNA and cytokine production. Encephalitogenic T cells recovered from treated mice were hypo-responsive to myelin antigen and failed to adoptively transfer the disease. Microarray analyses showed significant suppression of pro-inflammatory transcripts with concomitant induction of anti-inflammatory genes including Ptgds and Hsd11b1. Finally, triterpenoids induced oligodendrocyte maturation in vitro and enhanced myelin repair in an LPC-induced non-inflammatory model of demyelination in vivo. These results demonstrate the unique potential of triterpenoid derivatives for the treatment of neuroinflammatory disorders such as MS
LPA Is a Chemorepellent for B16 Melanoma Cells: Action through the cAMP-Elevating LPA5 Receptor
Lysophosphatidic acid (LPA), a lipid mediator enriched in serum, stimulates cell migration, proliferation and other functions in many cell types. LPA acts on six known G protein-coupled receptors, termed LPA1–6, showing both overlapping and distinct signaling properties. Here we show that, unexpectedly, LPA and serum almost completely inhibit the transwell migration of B16 melanoma cells, with alkyl-LPA(18∶1) being 10-fold more potent than acyl-LPA(18∶1). The anti-migratory response to LPA is highly polarized and dependent on protein kinase A (PKA) but not Rho kinase activity; it is associated with a rapid increase in intracellular cAMP levels and PIP3 depletion from the plasma membrane. B16 cells express LPA2, LPA5 and LPA6 receptors. We show that LPA-induced chemorepulsion is mediated specifically by the alkyl-LPA-preferring LPA5 receptor (GPR92), which raises intracellular cAMP via a noncanonical pathway. Our results define LPA5 as an anti-migratory receptor and they implicate the cAMP-PKA pathway, along with reduced PIP3 signaling, as an effector of chemorepulsion in B16 melanoma cells
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