Thyroid hormones concentration in portal and peripheral blood in patients with pancreatic cancer: Preliminary study.

BACKGROUND: The prognostic value of D-dimers concentration in portal blood in patients with pancreatic cancer has been established in several studies. Thyroid hormones and their receptors, especially T3 also seems to have a specific role in process of neoplasia and metastatic spread. OBJECTIVE: The aim of the study was to look for changes of thyroid hormones concentration between portal and peripheral blood. METHODS: We included prospectively 8 patients with pancreatic cancer, without liver dysfunction, qualified to surgical treatment. D-dimers, THS, fT3, fT4 concentration was determined in blood samples from portal and peripheral vein taken intraoperatively. RESULTS: The difference and quotient of portal and peripheral concentration of D-dimers, THS, fT3 and fT4 was calculated (D-dimer-; THS-; fT3-; fT4-d and -q). The level of D-dimers measured in portal blood was > 2700 ng/mL in 3 patients. The peripheral fT3 level was significantly higher In high portal D-dimers group. FT3 change coefficients showed strong statistically significant negative correlation with portal D-dimer concentration level. CONCLUSIONS: We suggest that fT3 or its receptors can influence progression of pancreatic malignancies. The results of this study are also a new evidence that both fT3 and portal D-dimers are biologically linked to intensity of local neoplastic process. Nevertheless, deeper knowledge about portal circulation probably constitute missing part in understanding nature of pancreatic neoplasia. Investigations both on larger group and in the field of basic sciences are needed.

Fetal liver hematopoietic stem cell niches associate with portal vessels.

Whereas the cellular basis of the hematopoietic stem cell (HSC) niche in the bone marrow has been characterized, the nature of the fetal liver niche is not yet elucidated. We show that Nestin(+)NG2(+) pericytes associate with portal vessels, forming a niche promoting HSC expansion. Nestin(+)NG2(+) cells and HSCs scale during development with the fractal branching patterns of portal vessels, tributaries of the umbilical vein. After closure of the umbilical inlet at birth, portal vessels undergo a transition from Neuropilin-1(+)Ephrin-B2(+) artery to EphB4(+) vein phenotype, associated with a loss of periportal Nestin(+)NG2(+) cells and emigration of HSCs away from portal vessels. These data support a model in which HSCs are titrated against a periportal vascular niche with a fractal-like organization enabled by placental circulation.

Evaluation of equations predicting the net portal appearance of amino acid nitrogen in ruminants.

A better assessment of digestible protein and AA flows is required to improve the predictions of animal performance in ruminants (e.g., growth and yields of milk and milk protein). In that respect, 2 recent meta-analyses were conducted in our laboratory to establish the relationships between net portal appearance of AA nitrogen (NPA-AAN) and dietary characteristics either from the National Research Council (Washington, DC) or Institut National de la Recherche Agronomique (INRA; St Genès Champanelle, France). Three prediction equations were selected from these meta-analyses: one equation based only on N intake (NI) and 2 equations based on NI, the intake of neutral detergent fiber, plus the dietary concentration of either total digestible nutrients or digestible organic matter. In the current meta-analysis, 2 new equations were developed to predict NPA-AAN from the estimated supply of metabolizable protein (MP) and the protein truly digestible in the intestine (PDI). The reliability of these 5 equations to predict NPA-AAN was evaluated using an independent database. On average, NPA-AAN predictions based on the supply of MP or PDI had the highest coefficient of determination and the lowest root of mean square prediction error and mean and regression biases compared with predictions based on dietary characteristics, suggesting better reliability with the former. No major difference was detected between NPA-AAN predictions based on parameters from the National Research Council or INRA, except that predictions based on MP had the lowest mean and regression biases. In each equation, mean of residual NPA-AAN (observed NPA-AAN minus predicted values) was lowest and negative for sheep compared with dairy cows, suggesting that NPA-AAN were overpredicted in sheep. Many continuous variables biased NPA-AAN predictions based on NI only, but none of the tested variables biased the predictions based on the supply of MP or PDI, corroborating the better reliability for the prediction equations based on the supply of digestible protein. Of the tested continuous variables, only the dietary concentration of crude protein (CP) biased NPA-AAN predictions based on NI plus dietary characteristics. The NPA-AAN responses to dietary CP concentration were overpredicted as dietary CP concentration increased and underpredicted as CP decreased, suggesting that ruminants were more efficient at converting ingested N into digestible protein when fed low-CP diets compared with high-CP diets.

Endotoxinemia in the portal and the systemic circulation in obstructive jaundice.

Endotoxinemia in patients with obstructive jaundice is linked to acute renal failure and sepsis and remains a major cause of complications during postoperative treatment. The current study examines the mechanisms of endotoxinemia in the portal and the systemic circulation in obstructive jaundice. As an experimental model of the disease we used rabbits subjected to sham operation. Serum total bilirubin aminotransferases and endotoxin concentrations were determined at 2, 5, 8, and 13 days after operation. Endotoxin concentrations were estimated by the limulus lysate endotoxin test. A high frequency of portal or systemic endotoxinemia is observed in obstructive jaundice, but no difference between endotoxinemia levels in the portal and systemic circulation was observed.

Endogenous benzodiazepine activity in the peripheral and portal blood of dogs with congenital portosystemic shunts.

OBJECTIVE: The purpose of this study was to determine whether an endogenous benzodiazepine receptor ligand (EBZ) was present in the arterial and portal blood of dogs with congenital portosystemic shunts (CPSS). STUDY DESIGN: The presence or absence of an EBZ was determined by the collection of systemic and portal blood from dogs with CPSS. ANIMALS: Fifteen client-owned dogs with a confirmed CPSS. All dogs had historical signs compatible with hepatic encephalopathy. Eight healthy dogs were used as controls. METHODS: In all dogs, systemic blood samples were collected after they were anesthetized. Portal blood samples were collected intraoperatively. EBZ was measured by radioreceptor assay. RESULTS: In 10 of 15 dogs, the portal blood concentration of EBZ was significantly elevated compared with normal dogs (mean, 13.2 +/- 18.55 ng/mL). Five dogs had elevated systemic blood EBZ levels (mean, 8.2 +/- 16.08 ng/mL). Eleven of 15 dogs had a higher portal than systemic blood concentration of EBZ. In contrast, control dogs had extremely low EBZ concentrations detected in their portal blood (mean, 0.16 +/- 0.3 ng/mL) and systemic blood (0 ng/mL). The mean portal and systemic blood concentrations in dogs with CPSS were significantly greater than in control dogs (P < .05). CONCLUSIONS: Elevated blood levels of EBZ were found in dogs with CPSS. The portosystemic gradient noted in 11 dogs suggests the gastrointestinal tract as a possible source for the endogenous ligand. CLINICAL RELEVANCE: Generalized motor seizures have been reported in dogs after surgical correction of CPSS. If the presence of a CPSS results in stimulation of brain receptors for benzodiazepines, post-CPSS ligation seizures may result from a withdrawal of EBZ after ligation of the portosystemic shunt.

Portal and biliary phases of enterohepatic circulation of corrinoids in humans.

The assimilation of labeled cobalamin and the transport of corrinoids in portal blood, peripheral venous blood, and bile were studied in eight cholecystectomized patients, after ingestion of a dose of cyano[57Co]cobalamin (0.5 microCi). The radioactivity appeared in the portal vein after a delay of 1.5-2 hours and in the peripheral vein 1 hour later. In bile, it reached a maximum at 24-72 hours; the excreted cobalamin corresponded to 1.42% +/- 0.92% of the dose ingested. The output of total corrinoids was 1.85 nmol/day. The high-performance liquid chromatography analysis of bile showed the presence of methylcobalamin, 5'-deoxyadenosylcobalamin, hydroxocobalamin, and an unknown corrinoid. This corrinoid bound to R binder but not to the intrinsic factor, and it had the same retention time as cobinamide. The R binder was the single cobalamin-binding protein found in bile. It was completely saturated in some periods of bile secretion. The corrinoids corresponding to such a period were eluted in Sephacryl S 300 gel filtration (Pharmacia Fine Chemicals, Uppsala, Sweden) in two peaks corresponding to saturated R binder and to free cobalamin. The mean level of total corrinoid was significantly higher in the portal vein (593 +/- 238 pmol/L) than in the peripheral vein (376 +/- 114 pmol/L) (P less than 0.01). This "cobalamin analogue" fraction was hypothetical because it was calculated from the difference between total corrinoid concentration and the so called "true cobalamin" concentration. This difference corresponded to the cobalamin analogue fraction. These data show that bile removes not only cobalamin but also cobalamin analogues and that R binder is the single carrier protein involved in their excretion.