Surfactant-like material on the chemoreceptorial surface of the frog's taste organ: an ultrastructural and electron spectroscopic imaging study

Tannic acid treatment was used to study the morphology of surfactant-like material (SLM) in the taste organ of Rana esculenta and the relation between this material and the cell types of the organ. On the surface of the taste organ SLM was associated with the apical processes of wing and putative taste cells. In SLM, a biphasic pattern was visible, a portion showed a lamellar periodicity (the repeating period of lamellae approximated 45 A), and a second portion showed an homogeneous electron density. Electron spectroscopic imaging revealed the presence of phosphorus and a large amount of calcium associated with the SLM. The result of our work suggests that SLM has a role in the perireceptorial events in the gustatory transduction by concentrating calcium in specific sites of the chemoreceptorial surface

A Tool to Support Complex Detective Inquiries

We present the architecture of an Inquiry Support System whose aim is to help a detective or a judge in: 1. generating hypotheses (automatically in some stereotypical cases), 2. eliciting a maximally consistent set of beliefs as the most believable piece of knowledge to reason with; this is done by: 2.1. finding the incoherences inside and across the various depositions, 2.2. generating the alternate maximally consistent sets of beliefs, 2.3. estimating the credibilities of the various evidences, 2.4. estimating the reliabilities of the various informants. The solution of the case is intended to be searched among the various possible plots compatible with the maximally consistent set of beliefs retained by the system as the most believable one

Secretory gralunes of endocrine and chief cells of human stomach mucosa contain leptin

BACKGROUND: Leptin plays an important role in the control of food intake and body weight homeostasis. In humans, leptin is produced by adipocytes, placental cells and secretory cells of the mammary epithelium. Recently, it has been reported that stomach glands produce leptin in rats. OBJECTIVE: To test the expression of leptin protein in human stomach and localize, by immunocytochemistry. the specific cell type producing leptin. DESIGN: Endoscopic stomach biopsies of six patients were used to investigate leptin production in the fundic epithelium using reverse transcription polymerase chain reaction (RT-PCR) of RNA. Leptin protein was detected by immunoblot analysis and localized by immunohistochemistry and ultrastructural immunocytochemistry (immunogold method). RESULTS: Human gastric epithelium expresses leptin mRNA and leptin protein. The cells in the lower half of the stomach glands were immunoreactive for leptin. Ultrastructural immunocytochemistry showed leptin immunoreactivity in the pepsinogen granules of chief cells, but the granules of a specific endocrine cell type in the basal portion of the glands were also positive. CONCLUSIONS: Our results suggest that gastric leptin could function in the short-term system to control feeding behaviour and is probably secreted in the stomach lumen by chief cells and into the stomach circulation by a special type of endocrine cell

Secretory granules of endocrine and chief cells of human stomach mucosa contein leptin.

BACKGROUND: Leptin plays an important role in the control of food intake and body weight homeostasis. In humans, leptin is produced by adipocytes, placental cells and secretory cells of the mammary epithelium. Recently, it has been reported that stomach glands produce leptin in rats. OBJECTIVE: To test the expression of leptin protein in human stomach and localize, by immunocytochemistry. the specific cell type producing leptin. DESIGN: Endoscopic stomach biopsies of six patients were used to investigate leptin production in the fundic epithelium using reverse transcription polymerase chain reaction (RT-PCR) of RNA. Leptin protein was detected by immunoblot analysis and localized by immunohistochemistry and ultrastructural immunocytochemistry (immunogold method). RESULTS: Human gastric epithelium expresses leptin mRNA and leptin protein. The cells in the lower half of the stomach glands were immunoreactive for leptin. Ultrastructural immunocytochemistry showed leptin immunoreactivity in the pepsinogen granules of chief cells, but the granules of a specific endocrine cell type in the basal portion of the glands were also positive. CONCLUSIONS: Our results suggest that gastric leptin could function in the short-term system to control feeding behaviour and is probably secreted in the stomach lumen by chief cells and into the stomach circulation by a special type of endocrine

Leptin in the human stomach

Secretory granules of both endocrine and chief cells of the stomach contain leptin. It is probably secreted in the stomach lumen by chief cells and into the stomach circulation by a special type of endocrine cell. The observation that intravenous infusions of pentagastrin or secretin caused an increase in circulating leptin levels and leptin release into gastric juice is in keeping with both endocrine and exocrine secretory sources. They could function in the short term system to control feeding behaviour and in the gastrointestinal lumen to regulate the availability of nutrients acting in the sites where a non-degraded form of hormone would approach.There is a need for further investigation in humans, with difficulties arising from ethical limitations. However, we can conclude that three important pathways (endocrine, exocrine, and autocrine) for the action of leptin are present in human stomach, where the main physiological role for this hormone is foreseen