K. Kan

Modulation of thermogenic response to parenteral amino acid infusion in surgical stress.

Thermogenic response to parenteral infusion of amino acid mixtures in rats undergoing surgical stress was investigated with the aid of a small animal indirect calorimeter. Male Wistar rats (n = 12) were laparotomized and received intestinal abrasion along with construction of a parenteral route. After 48 h, nutrient-induced thermogenesis (NIT) produced by amino acid mixtures was examined and compared with that of control rats (n = 12) without surgical stress. The NIT values of the leucine-enriched solution were greater than those of the control solution in both rats with and without surgical stress. The NIT generated by the leucine-enriched solution in rats with surgical stress was significantly higher than that in rats without. NIT values for 10 different kinds of single amino acid solutions with identical concentrations was then examined in 60 rats. The NIT values of the leucine and the glycine solutions were relatively higher than those of other solutions. However, when puromycin was injected intraperitoneally into 12 rats just before measurement of the NIT in response to amino acid mixtures, no significant differences were found in NIT values between the mixtures. In summary, surgical stress increased the thermogenic response to the leucine-enriched solution, indicating that utilization of leucine may be augmented under surgical stress. In fact, leucine itself may be a thermogenic amino acid. Inhibition of protein synthesis prevented the increase in thermogenic response induced by the leucine-enriched solution. We conclude that thermogenic responses to parenteral amino acid mixtures may differ depending not only upon the compositions of amino acids but also upon the host conditions.

Interrelation of Intracellular Proteases With Total Parenteral Nutrition-Induced Gut Mucosal Atrophy and Increase of Mucosal Macromolecular Transmission in Rats

Total parenteral nutrition (TPN) is known to induce mucosal atrophy and to increase macromolecular transmission of the small intestine. The potential participation of various proteases in that process was investigated. Male Wistar rats were randomly divided into two groups: the TPN group (n = 11) received a standard TPN (250 kcal/kg per day, 1.78 g nitrogen/kg per day) and the FED group (n = 10) received a standard rat food for 1 week. This was followed by an examination of gut macromolecular transmission of fluorescein isothiocyanate dextran 70,000 (FITC-dextran) after intragastric injection and of the activities of gut mucosal cathepsins B, H, and L and of proteasome. Mucosal wet weight and protein content decreased significantly by TPN for 1 week. In both groups, the activities of all proteases in the ileum were significantly greater than in the jejunum. In the TPN group, cathepsin L and H activities in the ileum, and cathepsin B activity in both the jejunum and the ileum, were greater than those in the FED group. The portal concentration of FITC-dextran was higher than arterial and venous concentrations in the both groups. In the TPN group, the portal FITC-dextran concentration increased significantly compared with the FED group. In conclusion, active proteolysis is not associated with TPN-induced mucosal atrophy. Cathepsins activities in the ileum increase as a result of TPN. Interrelationship is implicated between increase of lysosomal protease activity and the deterioration of the intestinal barrier function, which permits macromolecular transmission.

Regulation of albumin synthesis after hepatectomy and in the acute inflammation phase of rat liver

Abstract Hepatic albumin synthesis is down-regulated after both inflammation and hepatectomy. The transcriptional control of albumin synthesis was investigated in models of both conditions to differentiate the underlying mechanisms. Male Donryu rats underwent 70% hepatectomy or turpentine injection. Serum albumin and mRNA levels of albumin and promoter binding proteins (D site binding protein [DBP] CCAAT/enhancer binding protein-α[ C EBP -α], -β , and hepatocyte nuclear factor-1 [HNF-1]) in the liver were measured from 0 to 96 hr. After hepatectomy, the albumin mRNA level decreased to 0.6 at 36 hr and then recovered. After turpentine injection, it decreased to 0.4 at 36 hr and then recovered. The serum level of albumin decreased in a time-dependent manner in both models. The C EBP -α mRNA level decreased to 0.5 at 6 and 12 hr after hepatectomy and to 0.6 at 24 hr after turpentine injection. The DBP mRNA level decreased to 0.3 at 6 hr, to 0.2 at 24 hr after hepatectomy, and to 0.3 at 30 hr after turpentine injection. The C EBP -β mRNA level increased to 1.7 at 3 hr after hepatectomy and to 1.5 at 12 hr after turpentine injection. On the other hand, HNF-1 mRNA levels showed no consistent change in either model. The change in mRNA of the nuclear factors ( C EBP -α, C EBP -β , and DBP) thus precedes that of albumin. In conclusion, transcriptional regulation of albumin synthesis in the regenerating and the acute inflammation phase of the liver can be assessed by monitoring the mRNA levels of nuclear factors. The mechanisms for down-regulation of albumin in both conditions share substantial similarities.

Establishment of a multi-dose study of chondroitin sulfate iron colloid for evaluation of the reticuloendothelial system function

The assay system of chondroitin sulfate iron colloid (CSFe) was established to evaluate the reticuloendothelial system (RES) function in individual rabbits. In the multi-dose study of CSFe, CSFe was repeatedly administered to each individual rabbit with increasing doses (0.6, 1.2, 2.4, 6.0 mg/kg) at set intervals. Blood samples were serially collected after injection of CSFe and the concentration of CSFe in serum was directly measured as an iron concentration by modifying the previously described assay method [1] to minimize the sample volume. The clearance rate of CSFe at each injected dose was computed by the least-squares method and the double-reciprocal plotting of the doses against the phagocytic velocities by the Lineweaver-Burk method was obtained in each rabbit. The maximum phagocytic velocity (Vmax) and the CSFe concentration producing 1/2 Vmax (Kp) obtained in ten rabbits were 0.129 +/- 0.025 mg/kg per min and 0.417 +/- 0.121 mg/kg (mean +/- S.D.), respectively. The results obtained from this multi-dose study were comparable to our previous results obtained from the mean values of five groups given different doses [1]. The clearance rates of CSFe (0.6, 1.2, 6 mg/kg) decreased after the co-injection of 80 mg/kg of carbon colloid. The calculated Vmax and Kp in 29 rabbits were 0.125 mg/kg per min and 1.167 mg/kg. The Kp was apparently greater than that of the control (Vmax = 0.128 mg/kg per min, Kp = 0.421 mg/kg). Carbon colloid (80 mg/kg) was injected to six rabbits after the completion of the first multi-dose study of CSFe and then the second multi-dose study of CSFe was repeated after 24 h. No differences were found in Vmax and Kp between the two studies as were in the control group (10 rabbits) where saline was injected instead of carbon colloid. These results indicated that carbon colloid (80 mg/kg) gives a competitive and reversible inhibition on the RES. This multi-dose study of CSFe may be applicable for a bed-side analysis of the RES function in a patient.

Nutrient-induced thermogenesis (NIT) following amino acid infusion.

Nutrient-induced thermogenesis (NIT) induced by parenteral infusion of amino acid (AA) mixtures of different composition and of the same AA mixtures given via different routes (parenteral or intraportal infusion) were investigated in rats using a small animal indirect calorimeter. When 8 different AA solutions of differing composition but with the same total concentration were infused parenterally, both standard NIT (each AA is assumed to generate 3.28 kcal/g) and specific NIT (heat energy of each AA is calculated assuming that it is oxidized to carbon dioxide and water, and metabolised to urea and sulphuric acid) values of the leucine (Leu)-rich and the glycine (Gly)-rich solutions were significantly greater than those of the control solution. Removal of Leu or Gly from the respective AA solutions reversed the increase of both NIT values down to control levels. When the parenteral and portal infusion routes were used in one rat, both NIT values for parenteral infusion of the Leu-rich solution were again significantly greater than those of the control. Likewise, both NIT values for intrportal infusion of the Leu-rich solution were also significantly greater than those of the control. However, no difference in NIT values was found between parenteral and portal infusion of either solution. The result of this study indicated that Leu and Gly may be thermogenic AAs, and the thermogenic effect of Leu is not dependent upon the route of infusion.

Dynamic change of reticuloendothelial system function after surgical stress

The influence of surgical stress on the function of the reticuloendothelial system (RES) is not well elucidated. Because we established an in vivo functional test for the RES by using chondroitin sulfate iron colloid in rabbits, the normal range of RES function in healthy volunteers (n = 12) and the dynamic change of RES function in surgical patients after distal gastrectomy (n = 14) were examined by this method. In healthy volunteers, the maximum phagocytic velocity and membrane-particle constant were 0.0310 +/- 0.0052 mg/kg per minute and 0.575 +/- 0.205 mg/kg, respectively. In surgical patients, maximum phagocytic velocity (postoperative day 1, 0.0408 +/- 0.0088; postoperative day 3, 0.0486 +/- 0.0115; and postoperative day 7, 0.0430 +/- 0.0115 mg/kg per minute) and membrane-particle constant (postoperative day 3, 0.717 +/- 0.169 mg/kg) significantly increased postoperatively in comparison with preoperative values. These results indicate that the total capacity of the RES is augmented but that its functional phagocytic efficiency is diminished after abdominal surgery. This phenomenon is considered to be one of the immunological alterations caused by surgical stress. The chondroitin sulfate iron colloid test can be applied to monitor the dynamic change of the RES function under various conditions.

SYNCHRONOUS MULTICENTRIC SIGNET-RING CELL CARCINOMA OF THE STOMACH

A case of simultaneous multicentric signet‐ring cell carcinoma (SRC) of stomach is presented. Initially, an early gastric cancer (IIc) was diagnosed and this was cured with distal gastrectomy. Thirty‐eight months after the operation, follow‐up endoscopy revealed a tiny mucosal discoloration lesion, which was diagnosed as a minute SRC focus with biopsy. This was successfully treated with endoscopic mucosal resection (EMR). Nine months later, gastroscopy discovered another small mucosal lesion and it was again diagnosed as a tiny SRC lesion, which was also successfully treated with EMR. After a further 2 months, endoscopy showed three small mucosal lesions (discoloration) similar to previous lesions, two of which proved to be SRC with biopsy. As these lesions distributed widely over the remnant stomach, total gastrectomy of the residual stomach was performed. Pathological examination demonstrated a total of 22 simultaneous multifocal SRC lesions, which were all very small mucosal cancer. These cancers, including previously EMR‐treated ones, seemed to develop in a multicentric manner, as they were diagnosed within 11 months. This case also indicated that even subtle endoscopic findings should vigorously be sought and, if in doubt, be biopsied in order to locate gastric cancer early enough for minimal invasive curative treatment to be feasible.

Effect of platelet on protein degradation in rat skeletal muscle.

The effects of activated platelet (Plt) on muscle degradation were investigated, employing the in vivo disseminated intravascular coagulation (DIC) model induced by thrombin injection and the in vitro tissue culture system of skeletal muscles in rats. Both the release of tyrosine and leucine into the culture medium during 2 h incubation from the muscles harvested 30 min after thrombin injection increased by about 50% compared with control muscles. The addition of thrombin-activated platelet supernatant (TAPS) significantly increased the release of leucine into the incubation medium of the soleus muscles dissected from normally fed rats by 31% in comparison with the respective controls. No significant effect was observed in terms of the release of tyrosine or leucine from the incubated muscles by aspirin treatment before obtaining TAPS, or by the addition of thrombin itself up to the concentration of 0.67 micron/ml which was contained in the incubation medium of TAPS. These data suggest that protein catabolism is accelerated in the muscle from the thrombin-treated rats exhibiting DIC. The supernatant of activated Plt might contain a factor which modulates protein metabolism. That factor is different from prostaglandins or thrombin. Thus, active consumption of Plt may contribute to an increase of muscle breakdown in various catabolic states.