Peptide-YY (PYY) is a novel enteric peptide that is structurally related to pancreatic polypeptide and neuropeptide-Y. The objectives of the present experiments were to characterize the following aspects of PYY metabolism: the distribution of PYY in the canine gastrointestinal tract, the release of PYY in response to oral ingestion of a mixed meal or intraduodenal (ID) administration of oleic acid, the effect of ileocolectomy on the release of PYY in response to ID administration of oleic acid when transit of chyme to the distal ileum and colon is prevented, the effect of interruption of intramural neural pathways of the small bowel on the release of PYY, and the effect of iv cholecystokinin on the release of PYY. The results of these experiments demonstrate that PYY immunoreactivity is distributed primarily in the terminal ileum, colon, and rectum. Circulating levels of PYY increase significantly (P less than 0.05) within 10-30 min after ingestion of a meal or to ID administration of a fatty acid. Complete interruption of the flow of chyme to the site of PYY-containing cells (i.e. ileum-colon) did not block the release of PYY; however, ileocolectomy abolished the release of PYY in response to ID administration of oleic acid. Severance of intramural neural pathways along the small bowel did not alter the release of PYY in response to an oral meal. Intravenous administration of graded doses of cholecystokinin stimulated the release of PYY in a dose-related manner. The results of these experiments indicate that the release of PYY from the distal ileum and colon is controlled, at least in part, by an extramural neural, endocrine, or a combination of both types of mechanisms which originate in the foregut.

The objective of this study was to compare the effects of various nutrients (fats, proteins, amino acids, and carbohydrates), given directly into the duodenum or the colon, on the release of peptide-YY (PYY) in conscious dogs. As reported previously, this study showed that plasma levels of PYY increased significantly (P less than 0.05) within 15 min in response to an oral mixed meal. Intraduodenal (ID) administration of a fatty acid (oleic acid; 100 mmol/L; 100 ml/h) stimulated a robust release of PYY, whereas ID administration of an amino acid mixture (phenylalanine plus tryptophan; 100 mmol/L each; 100 ml/h), glucose (1 g/kg), or a liver extract (10%; 100 ml/h) failed to elevate plasma levels of PYY. ID administration of glucose at 2 g/kg caused a mild but significant elevation in plasma PYY levels. Intracolonic administration of saline, a fatty acid, an amino acid mixture, glucose, or a liver extract significantly stimulated PYY release. This study suggests that as chyme moves from the stomach to the proximal bowel, fat is the primary constituent of food that stimulates the prompt release of PYY. However, unabsorbed nutrients can release PYY by a direct contact with the PYY-containing cells lining the intestinal lumen of the terminal ileum, colon, and rectum. Both mechanisms probably participate in the release of PYY.

The fragmented red cell (FRC) is a useful index for diagnosing and determining the severity of thrombotic thrombocytopenic purpura (TTP), thrombotic microangiopathy (TMA) and other similar conditions, as it is found in peripheral blood in patients with these diseases. The FRC expression rate has conventionally been determined by manual methods using smear samples. However, it is difficult to attain accurate quantification by such methods as they are time consuming and prone to a great margin of error. With cases of living donor liver transplantation, the current study examined the possibility of using a multi-parameter automated hematology analyzer, the XE-2100 (Sysmex Corporation) for FRC quantification. While there was a notable correlation between the manual and automated measurements, the manual measurement resulted in higher values. This suggested remarkable variations in judgment by individuals. The FRC values had a significant correlation with the reticulocyte count, red blood cell distribution width (RDW), fibrin/fibrinogen degradation products (P-FDP) and lactate dehydrogenase (LDH) among the test parameters, and this finding was consistent with the clinical progression in patients. The automated method can offer precise measurements in a short time without inter-observer differences, meeting the requirement for standardization. The determination of FRC count (%) by the XE-2100 that enables early diagnoses and monitoring of TTP or TMA will be useful in the clinical field.

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