84 research outputs found
Why regionality is an important value in organic agriculture: the case of the Netherlands
Organic agriculture is a system of production and consumption in which values play a prominent role. The new IFOAM principles reflect the current worldwide consensus on the most important values of organic agriculture. Regionality or proximity is not explicitly mentioned in these principles. Also in the present EU-regulation on organic agriculture hardly any standards are formulated concerning this issue. On the other hand, some private organic labels do have extra standards - concerning for instance the origin of organic feed - while both producers and consumers of organic products often mention regional production as an important value. The question is whether, and if so why regionality is an important issue to be dealt with in the upcoming reformed EU-regulation on organic agriculture. To answer this question, the consequences are evaluated of the de-velopment of intensive, large-scale organic animal production in the Netherlands in the light of the value of regionality
Lung dendritic cells and host immunity to infection
The lung is a portal of entry for numerous microbial pathogens, against
which evolution has created an adequate innate and adaptive immune
response. Dendritic cells (DCs) are central to the integration of innate
and specific immunity. These cells are located within the epithelium and
interstitium of the lung where they are influenced by the innate immune
system. Upon recognition and internalization of microbial antigens, DCs
migrate to the draining lymph nodes of the lung to initiate the specific
cellular and humoral immune response. By their capacity to integrate
stimuli derived from the pathogen, the host and the environment, they are
specialized to induce a protective immune response while at the same time
avoiding damage to the host. It is becoming increasingly clear that
dendritic cells are involved in the induction of immunity to viruses,
bacteria, mycobacteria and fungi. Some pathogens subvert the function of
dendritic cells to escape immune recognition. Not surprisingly, if
dendritic cell function fails, the consequence for the host is
immunodeficiency
Segmental bronchial provocation induces nasal inflammation in allergic rhinitis patients
Allergic rhinitis and asthma often coexist and share a genetic background.
Pathophysiologic connections between the nose and lungs are still not
entirely understood. This study was undertaken to compare allergic
inflammation and clinical findings in the upper and lower airways after
segmental bronchial provocation (SBP) in nonasthmatic allergic rhinitis
patients. Eight nonasthmatic, grass pollen-sensitive patients with
allergic rhinitis and eight healthy controls were included. Bronchial
biopsies and blood samples were taken before (T(0)) and 24 h (T(24)) after
SBP. Nasal biopsies were obtained at T(0), 1 h after SBP (T(1)), and
T(24). Immunohistochemical staining was performed for eosinophils (BMK13),
interleukin (IL)-5, and eotaxin. The number of eosinophils increased in
the challenged and unchallenged bronchial mucosa (p < 0.05) and in the
blood (p = 0.03) of atopic subjects at T(24). We detected an increase of
BMK13-positive and eotaxin-positive cells in the nasal lamina propria and
enhanced expression of IL-5 in the nasal epitheliu
Dyspnoea perception during clinical remission of atopic asthma
Symptoms of atopic asthma often disappear around puberty. The authors
recently demonstrated that this clinical remission is accompanied with
ongoing airways inflammation in most subjects. The discrepancy between
lack of symptoms and persistent airway inflammation suggests that
perception of the symptoms is unclear. In the present study, young adults
in clinical remission of atopic asthma assigned themselves a modified Borg
score during methacholine and adenosine-5'-monophosphate induced
bronchoconstriction. Borg scores of subjects in clinical remission were
compared with those of symptomatic asthmatic subjects. A marked variation
in the Borg scores at a 20% fall in the forced expiratory volume in one
second was found. Significant differences in Borg scores between remission
patients and asthmatics could not be detected. It was concluded that
perception of dyspnoea, induced with methacholine and adenosine challenge,
is similar in young adults in clinical remission of atopic asthma compared
to that of patients with symptomatic asthma. Hence, an unclear perception
seems to be an unlikely explanation for the discrepancy between lack of
symptoms and ongoing inflammation. Other factors, including both physical
and psychological ones, may play a role in the apparent absence of
symptoms, thereby potentially leading to undertreatment
Adolescents in clinical remission of atopic asthma have elevated exhaled nitric oxide levels and bronchial hyperresponsiveness
Symptoms of atopic asthma often decrease or even seem to disappear around
puberty. The aim of this study was to investigate whether this so-called
clinical remission is accompanied by remission of airway inflammation,
since symptoms relapse in a substantial proportion of subjects later in
life. To assess indicators of inflammation and/or structural damage of the
airways, exhaled nitric oxide (eNO) and bronchial responsiveness to
adenosine-5'-monophosphate (AMP) and methacholine (MCh) were determined in
21 subjects in clinical remission of atopic asthma. Clinical remission was
defined as complete absence of symptoms of asthma without the use of any
medication in the year preceding the study. Results were compared with
those of 21 patients with current asthma and 18 healthy control subjects.
We found significantly higher eNO values in the remission group than in
healthy controls (geometric mean, 18.9 and 1.0 ppb, respectively; p <
0.001) whereas eNO values of the remission group and those of the subjects
with current asthma (geometric mean, 21.9 ppb) were similar (p = 0.09).
The responsiveness to both AMP and MCh of subjects in clinical remission
was significantly higher as compared with responsiveness of healthy
controls, and lower than responsiveness of subjects with current asthma. A
significant correlation could be established between eNO and
responsiveness to AMP, but not between eNO and responsiveness to MCh. The
results of this study are suggestive of persistent airway inflammation
during clinical remission of atopic asthma. We speculate that subclinical
inflammation is a risk factor for asthma relapse later in life, and that
eNO and responsiveness to both AMP and MCh can be used as different,
noninvasive indices of the inflammatory process of the airways
Lipopolysaccharide-induced suppression of airway Th2 responses does not require IL-12 production by dendritic cells
The prevalence of atopic asthma, a Th2-dependent disease, is reaching
epidemic proportions partly due to improved hygiene in industrialized
countries. There is an inverse correlation between the level of
environmental endotoxin exposure and the prevalence of atopic
sensitization. As dendritic cells (DC) have been implicated in causing
sensitization to inhaled Ag, we studied the effect of endotoxin on Th2
development induced by bone marrow DC in vitro and by intratracheal
injection in vivo, with particular emphasis on the role played by the
polarizing cytokine IL-12. Bone marrow-derived DC stimulated with
Escherichia coli O26:B6 LPS produced IL-12p70 for a limited period of
time, after which production became refractory to further stimulation with
CD40 ligand, a phenomenon previously called "exhaustion." The level of
IL-12 production of DC did not correlate with Th1 development, as
exhausted OVA-pulsed DC were still capable of shifting the cytokine
pattern of responding OVA-specific Th cells toward Th1 in vitro and in
vivo. When mice were first immunized by intratracheal injection of OVA-DC
and subsequently challenged with OVA aerosol, prior in vitro stimulation
of DC with LPS reduced the development of airway eosinophilia and Th2
cytokine production. Most surprisingly, the capacity of LPS to reduce
Th2-dependent eosinophilic airway inflammation was IL-12-independent
altogether, as IL-12p40 knockout DC had a similar reduced capacity to
prime for Th2 responses. These results suggest that LPS reduces
sensitization to inhaled Ag by reducing DC-driven Th2 development, but
that IL-12 is not necessary for this effect
Segmental bronchoprovocation in allergic rhinitis patients affects mast cell and basophil numbers in nasal and bronchial mucosa
Mast cells and basophils are cells that play an important role in the
initiation and control of allergic inflam
iPSC-based modeling of RAG2 severe combined immunodeficiency reveals multiple T cell developmental arrests
RAG2 severe combined immune deficiency (RAG2-SCID) is a lethal disorder caused by the absence of functional T and B cells due to a differentiation block. Here, we generated induced pluripotent stem cells (iPSCs) from a RAG2-SCID patient to study the nature of the T cell developmental blockade. We observed a strongly reduced capacity to differentiate at every investigated stage of T cell development, from early CD7(-)CD5(-) to CD4(+)CD8(+). The impaired differentiation was accompanied by an increase in CD7(-)CD56(+)CD33(+) natural killer (NK) cell-like cells. T cell receptor D rearrangements were completely absent in RAG2SCID cells, whereas the rare T cell receptor B rearrangements were likely the result of illegitimate rearrangements. Repair of RAG2 restored the capacity to induce T cell receptor rearrangements, normalized T cell development, and corrected the NK cell-like phenotype. In conclusion, we succeeded in generating an iPSC-based RAG2-SCID model, which enabled the identification of previously unrecognized disorder-related T cell developmental roadblocks
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