517 research outputs found
Histamine H3 and H4 receptors are expressed on distinct endocrine cell types in the rat fundic mucosa
No full textThe present study was designed to explore the expression and distribution of histamine H3 and H4
receptors within the rat gastric fundus by immunohistochemistry using our unique immunological
probes. Groups of rats were either fed ad libitum or fasted for 24h before the sacrifice. Tissue
samples from the fundic region of the stomach were removed, fixed and processed for
immunohistochemistry, using our validated anti-H3 (349-358) and anti–H4 (374-390) antibodies.
The results showed that cells immunoreactive for H3R and H4R are located in the fundic epithelium.
The vast majority of H3R immunopositive cells occupied the lower half of the glands, and were
absent in the superficial portion. Their number per gland was 5.38 ± 0.19 in freely fed rats and 3.21
± 0.40 in fasted rats. Conversely, cells immunoreactive for H4R were dispersed throughout the
glands. Their number per gland was 0.75 ± 0.03 in fed rats and 0.90 ± 0.05 in fasted rats. Double
immunostaining revealed that the H3R is not colocalized with the H4R, while both H3R and H4R
positive cells were immunoreactive for chromogranin A, suggesting that these immunopositive cells
are endocrine cells. Because five different endocrine cell types have been identified in the rat fundic
epithelium, we used double immunostaining to identify the cell types expressing H3R and H4R,
respectively. Approximately 90% of cells positive for H3R were also immunoreactive for histidine
decarboxylase, demonstrating that the H3R is located on ECL cells. Cells positive for H4R were
immunoreactive for ghrelin, originating from A-like cells.
These findings may imply that histamine, via a balanced interaction with H3R and H4R expressed
on ECL and A-like cells respectively, regulates not only acid secretion and mucosal protection but
could also have a role in feeding behaviour and growth hormone release
Immunolocalization of histamine H3 receptors on endocrine cells in the rat gastrointestinal tract
No full textThe histamine H3 receptor (H3R) has been identified in the gastrointestinal tract of the rat by immunohistochemistry, using the first validated anti-H3 receptor antibody. Immunoreactivity to H3R was exclusively localized to the endocrine cells scattered in the gastrointestinal mucosa, with positive cells being prominently abundant in the gastric fundus, while they were rarely found in the other regions. In the fundus, positive cells were distributed in the lower half of the mucosa and their number significantly decreased after a 24 h-fasting period. Double-labeling studies were undertaken to identify the H3R-immunoreactive cell types in the fundic and antral mucosa. The H3R-immunoreactive cells were positive for chromogranin A. In the fundus, approximately 90% of cells positive to H3R were also positive to the histamine-forming enzyme, histidine decarboxylase. None of the cells expressing H3R displayed immunoreactivity for gastrin, somatostatin or ghrelin. Location, the influence of food deprivation and colocalization with histidine decarboxylase indicate that H3R positive cells correspond to the enterochromaffin-like cells (ECL)
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Moment series for the coefficient of variation in Weibull sampling
No full textFor the 2-parameter Weibull distribution function F(t) = 1 - exp(-t/b)/sup c/, t > 0, with c and b positive, a moment estimator c* for c is the solution of the equationGAMMA(1 + 2/c*)/GAMMA/sup 2/ (1 + 1/c*) = 1 + v*/sup 2/ where v* is the coefficient of variation in the form ..sqrt..m/sub 2//m/sub 1/', m/sub 1/' being the sample mean, m/sub 2/ the sample second central moment (it is trivial in the present context to replace m/sub 2/ by the variance). One approach to the moments of c* (Bowman and Shenton, 1981) is to set-up moment series for the scale-free v*. The series are apparently divergent and summation algorithms are essential; we consider methods due to Levin (1973) and one, introduced ourselves (Bowman and Shenton, 1976)
sj-pdf-1-jhc-10.1369_00221554221079579 – Supplemental material for Comprehensive BCMA Expression Profiling in Adult Normal Human Brain Suggests a Low Risk of On-target Neurotoxicity in BCMA-targeting Multiple Myeloma Therapy
No full textSupplemental material, sj-pdf-1-jhc-10.1369_00221554221079579 for Comprehensive BCMA Expression Profiling in Adult Normal Human Brain Suggests a Low Risk of On-target Neurotoxicity in BCMA-targeting Multiple Myeloma Therapy by Mathieu Marella, Xiang Yao, Vinicius Carreira, Marta F. Bustamante, H. Brent Clark, Carolyn C. Jackson, Enrique Zudaire, Jordan M. Schecter, Tynisha D. Glover, Jacintha Shenton and Ingrid Cornax in Journal of Histochemistry & Cytochemistry</p
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Estimation problems associated with the Weibull distribution
No full textSeries in descending powers of the sample size are developed for the moments of the coefficient of variation v* for the Weibull distribution F(t) = 1 -exp(-(t/b)/sup c/). A similar series for the moments of the estimator c* of the shape parameter c are derived from these. Comparisons are made with basic asymptotic assessments for the means and variances. From the first four moments, approximations are given to the distribution of v* and c*. In addition, an almost unbiased estimator of c is given when a sample is provided with the value of v*. Comments are given on the validity of the asymptotically normal assessments of the distributions
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