688 research outputs found
Frequency dependent deformation of liquid crystal droplets in an external electric field
Nematic drops suspended in the isotropic phase of the same substance were
subjected to alternating electrical fields of varying frequency. The system was
carefully kept in the isotropic-nematic coexistance region, which was broadened
due to small amounts of non-mesogenic additives. Whereas the droplets remained
spherical at low (order of 10 Hz) and high frequencies (in the kHz range), at
intermediate frequencies, we observed a marked flattening of the droplet in the
plane perpendicular to the applied field. The deformation of the liquid crystal
(LC) droplets occurred both in substances with positive and negative dielectric
anisotropy. The experimental data can be quantitatively modelled with a
combination of the leaky dielectric model and screening of the applied electric
field due to the finite conductivity.Comment: minor change
Effects of loperamide on the human hypothalamo-pituitary-adrenal axis in vivo and in vitro.
Loperamide, an opiate agonist of high specificity for p-receptors,
was recently reported to suppress ACTH and cortisol levels in normal
subjects, but not in patients with proven ACTH-dependent Cushing’s
disease. However, there is little information on the site of action of
loperamide in the hypothalamo-pituitary-adrenal axis of man. We
investigated the effect of loperamide on pituitary hormone secretion in
uiuo and in vitro. In seven normal subjects, basal ACTH plasma levels
were significantly suppressed 3 h after loperamide administration (16
mg, orally) from 5 + 1 to 2 f 0 pmol/L (P < 0.0001). After the combined
pituitary stimulation test (100 pg human CRH, 100 rg GnRH, 100 pg
GH-releasing hormone, and 200 pg TRH), the ACTH peak (maximum
increase at 30 min) was significantly blunted by loperamide from 9 +
1 to 4 of: 1 pmol/L (P < 0.001) and the area under the curve of ACTH
from O-120 min was reduced from 35 + 5 to 23 + 4 pmol/L.2 h (P <
0.05). In the insulin-hypoglycemia test (0.15 IU/kg BW), neither the
ACTH peak nor the area under the curve of ACTH was affected by
loperamide. In six patients with Cushing’s disease and one patient with
secondary adrenal insufficency due to hypothalamic failure, neither
basal ACTH and cortisol levels nor CRH-stimulated levels were influenced
by loperamide. In four cultured human corticotropic adenomas,
loperamide was not able to reduce basal and CRH-induced ACTH
secretion. In summary, loperamide is able to reduce basal and CRHinduced
ACTH and cortisol levels in normal subjects, but not in
patients with Cushing’s disease or secondary adrenal failure of hypothalamic
origin. Loperamide has no significant effect on insulin-hypoglycemia-
induced ACTH and cortisol levels and, therefore, no effect
on stress-induced elevation of cortisol levels. Loperamide might act at
a suprapituitary site in man in viuo, but, nevertheless, a pituitary site
cannot be excluded
X-By-Wire via ISOBUS Communication Network
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): X-By-Wire via ISOBUS Communication Network. Manuscript ATOE 07 002. Vol. IX. July, 2007
Preface to Special Section "ATOE 2006" of CIGR Ejournal Vol. IX
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): Preface to Special Section "ATOE 2006" of CIGR Ejournal Vol. I
Insulin-like growth factor I is an independent coregulatory modulator of natural killer (NK) cell activity.
We aimed to investigate the natural killer (NK) cell activity in
hGH-deficient adults and to analyze the effect of insulin-like growth
factor (IGF)-I in uivo and in vitro on NK cell activity. NK cell activity
was measured in a 4-h nonisotopic assay with europium-labeled and
cryopreserved K-562 cells. NK-cell numbers were measured after
incubation with murine monoclonal CD3 and CD16 antibodies by flow
cytometry analysis. In a cross-sectional study, the basal and interferon-
p (IFN-P) stimulated (1000 IU/ml) NK cell activity of 15 hGHdeficient
patients and 15 age- and sex-matched controls was measured.
The percentages and absolute numbers of CD3./16+ NK-cells
were not significantly different in the patient vs. control group. The
basal and IFN-P stimulated NK cell activity however was significantly
decreased in the patient vs. control group at all effecter/target
(E/T) cell ratios from 12.5-100 (e.g. 17 ? 3 vs. 28 ? 3% lysis without
IFN-P, P < 0.05, and 42 t 4 vs. 57 2 4% lysis with IFN-0, P < 0.05;
both at E/T 50). IGF-I levels of patients and controls showed a significant
positive correlation with NK cell activity (r = 0.37; P < 0.05).
In an IGF-I in vitro study (IGF-I in vitro 250-1250 kg/L), the basal and
IFN-P stimulated NK cell activity of 13 hGH-deficient patients and of
18 normal subjects was significantly enhanced by IGF-I in vitro (e.g.
GH-deficient patients: 9 ? 2 us. 10 2 2% lysis without IFN-P, P < 0.05
and 25 + 4 vs. 30 + 4% lysis with IFN-/3, P < 0.005; and normal
subjects: 15 + 3 vs. 23 ? 3% lysis without IFN-/3, P < 0.001 and 35 2
4 us. 44 + 5% lysis with IFN-P, P < 0.001; both at IGF-I 500 pg/L).
In summary, in our cross-sectional study, adult GH-deficient patients
showed a significantly lower basal and IFN-P stimulated NK cell
activity than matched controls, despite equal NK cell numbers. IGF-I
levels of patients and controls showed a weak positive correlation with
NK cell activity. In an in vitro study, IGF-I significantly enhanced
basal and IFN-P stimulated NK cell activity of hGH-deficient patients
and also of normal subjects. The decreased NK cell activity in GHdeficient
patients may be caused at least in part by low serum IGF-I
levels. IGF-I appears to be an independent coregulatory modulator of
NK cell activity. (Endocrinology 137: 5332-5336, 1996
Time-resolved X-ray microscopy of nanoparticle aggregates under oscillatory shear
Of all current detection techniques with nanometer resolution, only X-ray
microscopy allows imaging nanoparticles in suspension. Can it also be used to
investigate structural dynamics? When studying response to mechanical stimuli,
the challenge lies in applying them with precision comparable to spatial
resolution. In the first shear experiments performed in an X-ray microscope, we
accomplished this by inserting a piezo actuator driven shear cell into the
focal plane of a scanning transmission X-ray microscope (STXM). Thus
shear-induced reorganization of magnetite nanoparticle aggregates could be
demonstrated in suspension. As X-ray microscopy proves suitable for studying
structural change, new prospects open up in physics at small length scales.Comment: submitted to J. Synchrot. Radia
Therapeutic strategies for advanced neuroendocrine carcinomas of jejunum/ileum and pancreatic origin
Multimodal treatment options for advanced gastroenteropancreatic neuroendocrine tumours (NET) of jejunum/ileum and of pancreatic origin are reviewed. Current topics being discussed are: European Neuroendocrine Tumour Society 2006/7, American Joint Cancer Committee/Union Internationale Contre le Cancer 2009 and WHO 2010 recommendations for grading and staging of NET; surgery of the primary tumour in distant metastasised disease; surgery of metastatic liver disease and impact on survival; somatostatin analogues for symptom control and for tumour control; selective internal radiation therapy with 90Y-microspheres as novel local ablative therapy in liver metastases; peptide receptor radionuclide therapy; novel chemotherapy regimens (eg, temozolomide) and novel targeted therapies (eg, sunitinib and everolimus)
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