Results of modified uncut Roux-en-Y reconstruction after distal gastrectomy for gastric cancer

BACKGROUND/AIMS

The frequent occurrence of bile gastritis and esophagitis associated with dehiscence of 'uncut' jejunal portion was of concern for "uncut" Roux-en-Y reconstruction after distal gastrectomy. Our aim was to study if our technique of a modified, uncut Roux-en-Y procedure would decrease this dehiscence.

METHODOLOGY

Ten patients with gastric cancer underwent distal gastrectomy with a modified, uncut Roux-en-Y reconstruction. Transmural silk stitches were added around the staples at the "uncut" portion in attempt to prevent dehiscence of the staple line. Dehiscence of the jejunum at the enterically closed site was investigated endoscopically or fluoroscopically.

RESULTS

Mean operative time and intraoperative blood loss were 246 minutes and 381 mL, respectively. Morbidity occurred in three patients. No dehiscence was observed in any of the patients examined.

CONCLUSIONS

These results suggest the possibility that our technique of a modified, uncut Roux-en-Y reconstruction after distal gastrectomy decreases dehiscence of enterically closed portion.

Effect of viscosity of enteral nutrient on gut motility and hormone secretion in dogs

BACKGROUND/AIMS

Our aim was to study the effect of the viscosity of enteral nutrient solutions on upper gut motility and gut hormone secretion.

METHODOLOGY

We used 5 beagle dogs equipped with strain gauge force transducers to measure upper gastrointestinal motility. Upper gut motility and gut hormone secretion were compared across 6 experimental conditions; control (oral solid meal), liquid-120, liquid-5 (liquid enteral nutrients administered for 120 and 5 min, respectively), low, middle, and high viscosity conditions.

RESULTS

The magnitude of receptive relaxation was decreased in the liquid-120 compared to control, but this decrease was reversed with the increase of viscosity. The duration of the postprandial contractions in the proximal jejunum was decreased in the liquid-5 compared to the control, but this decrease was reversed in the middle and high viscosity conditions (p < 0.05). Rapid increase in plasma concentrations of gastric inhibitory polypeptide observed in the liquid-5 compared to the control was reversed in the low, middle, and high viscosity conditions.

CONCLUSIONS

Although patterns of upper gut motility and gut hormone secretion after liquid enteral nutrients were considerably altered compared to those after solid meal ingestion, increasing the viscosity of liquid enteral nutrients reversed those altered patterns.

[A case of anal cancer with rapidly rising CEA in longstanding perianal Crohn disease after infliximab administration]

Infliximab is effective in the treatment of steroid-resistant Crohn disease. However, there is clinical concern about a possible correlation between an increased risk of anorectal cancer and infliximab treatment. We report a case of anorectal cancer in long-standing perianal Crohn disease. A 34-year-old patient with a long-standing perianal lesion of Crohn disease underwent 3 sessions of infliximab therapy. After therapy, the concentration of plasma CEA was 36.5ng/ml and rose to 91.4ng/ml. We suspected anorectal cancer, so abdominoperineal resection was performed. The histological findings indicated mucinous adenocarcinoma. Monitoring of patients with long-standing perianal Crohn disease is considered essential for early diagnosis of anal cancer after obtaining biopsy samples from perianal lesions. Additionally, when infliximab is started for perianal Crohn disease, thorough examination for perianal lesion should be performed.

Intracolonic capsaicin stimulates colonic motility and defecation in conscious dogs

BACKGROUND

The aim of this study was to investigate the effects of intracolonic capsaicin on colonic motility and defecation.

METHODS

The effects of capsaicin (1, 2, 5, and 10 mg) administrated into the proximal colon on ileocolonic motility and defecation were studied in neurally intact dogs with or without various antagonists (atropine, hexamethonium, ondansetron, propranolol, and FK224), dogs with extrinsic denervation of an ileocolonic segment, and dogs with enterically isolated ileocolonic loops equipped with strain gauge force transducers.

RESULTS

Capsaicin at 5 and 10 mg evoked giant migrating contractions in a dose-independent manner, and it induced defecations with more than 90% probability in neurally intact dogs. These effects of capsaicin were abolished by atropine and hexamethonium. Ondansetron inhibited the capsaicin-induced increase in colonic motility but did not affect the induction of defecation. The other antagonists had no effect. In dogs with extrinsic denervation, capsaicin did not evoke giant migrating contractions in the colon but still induced defecation in 30-40% of experiments. In dogs with ileocolonic loops, capsaicin did not stimulate colonic motility nor induce defecation.

CONCLUSION

These results indicate that intracolonic capsaicin causes giant migrating contractions and defecation. Intact extrinsic innervation, continuity of the colon, and intraluminal contents were considered necessary for this effect.

[Laparoscopic biliary surgery]

Laparoscopic cholecystectomy has become the standard treatment for patients with symptomatic gallbladder disease. However, there is a substantial proportion of patients in whom laparoscopic cholecystectomy cannot be successfully performed, and conversion to open surgery is required because of technical difficulties or complications. The incidence of bile duct injury has increased in laparoscopic cholecystectomy. Meticulous dissection and intraoperative cholangiography could significantly reduce the rate of that injury. Laparoscopic cholecystectomy for acute cholecystitis is still controversial because of surgical difficulty. In our experience, early laparoscopic cholecystectomy is a beneficial option for patients with acute cholecystitis, and it may even be safe in the acute stage. A better alternative for high-risk early operation and septic cases is percutaneous transhepatic gallbladder drainage. The coexistence of gallbladder cancer should be ruled out and preoperative diagnosis should be done carefully. Laparoscopic management of common bile duct (CBD) stones has many advantages. However it has been reported to be demanding and time-consuming to perform, which limits its widespread adoption. In our experience with 258 patients, laparoscopic CBD exploration was feasible for almost all CBD stones. The technical difficulties associated with laparoscopic CBD exploration could be overcome with the development of suitable equipment and increased expertise.

LST-2, a human liver-specific organic anion transporter, determines methotrexate sensitivity in gastrointestinal cancers

BACKGROUND & AIMS

One approach to the development of targeted cancer chemotherapy exploits increased uptake of the agent into neoplastic cells. In this scenario, higher concentrations of the agent in cancer cells are responsible for differential killing, whereas the low concentration in normal human cells decreases side effects. The aim of this study was to isolate an organic anion transporter that is weak in normal cells, but abundantly expressed in cancer cells, to deliver the anticancer drugs to the cells.

METHODS

A human liver complementary DNA (cDNA) library was screened with liver-specific transporter (LST)-1 cDNA as a probe. Northern blot analyses were performed using the isolated cDNA (termed LST-2). An LST-2-specific antibody was raised, and immunohistochemical analyses including immunoelectron microscopy were performed. Xenopus oocyte expression system was used for functional analysis. We also established a permanent cell line that consistently expresses LST-2 to examine the relationship between methotrexate uptake and sensitivity.

RESULTS

The isolated cDNA, LST-2, has 79.7% of overall homology with human LST-1. LST-2 exclusively expressed in the liver under normal conditions and its immunoreactivity was highest at the basolateral membrane of the hepatocytes around the central vein. Although its weak expression in the liver, LST-2 is abundantly expressed in the gastric, colon, and pancreatic cancers. On the other hand, the LST-1 was only detected in a hepatic cell line. LST-2 transports methotrexate in a saturable and dose-dependent manner. Furthermore, introduction of the LST-2 gene into mammalian cells potentiates sensitivity to methotrexate.

CONCLUSIONS

LST-2 is one of the prime candidate molecules for determining methotrexate sensitivity and may be a good target to deliver anticancer drugs to the gastrointestinal cancers.

Molecular characterization and functional regulation of a novel rat liver-specific organic anion transporter rlst-1

BACKGROUND & AIMS

Recently, we isolated a new complementary DNA (cDNA) encoding human liver-specific organic anion transporter (LST-1), representing the multispecificity of human liver. The aim of this study was to isolate a rat counterpart of human LST-1 and examine the expression regulation of its messenger RNA (mRNA) to clarify the molecular basis of cholestasis.

METHODS

A rat liver cDNA library was screened with human LST-1 cDNA as a probe. Xenopus oocyte expression system was used for functional analysis. Northern blot analyses were performed using the isolated cDNA (termed rlst-1). The bile duct ligation model and the cecum ligation and puncture model were used for expression analyses.

RESULTS

rlst-1 encodes 652 amino acids, predicting at least 11 transmembrane regions. The overall homology with human LST-1 was 60.2%, which is the highest among all known organic anion transporters. rlst-1 also belongs to the same new gene family as human LST-1, located between the organic anion transporter family and the prostaglandin transporter. rlst-1 preferably transports taurocholate (K(m), 9.45 micromol/L) in an Na(+)-independent manner. The rlst-1 mRNA is exclusively expressed in the liver. In both the bile duct ligation model and the cecum ligation and puncture model, mRNA expression levels of rlst-1 were down-regulated.

CONCLUSIONS

rlst-1 is a counterpart of human LST-1 and is one of the important transporters in rat liver for the clearance of bile acid. The expression of rlst-1 may be under feedback regulation of cholestasis by biliary obstruction and/or sepsis.

Identification of a novel gene family encoding human liver-specific organic anion transporter LST-1

We have isolated a novel liver-specific organic anion transporter, LST-1, that is expressed exclusively in the human, rat, and mouse liver. LST-1 is a new gene family located between the organic anion transporter family and prostaglandin transporter. LST-1 transports taurocholate (Km = 13.6 microM) in a sodium-independent manner. LST-1 also shows broad substrate specificity. It transports conjugated steroids (dehydroepiandrosterone sulfate, estradiol-17beta-glucuronide, and estrone-3-sulfate), eicosanoids (prostaglandin E2, thromboxane B2, leukotriene C4, leukotriene E4), and thyroid hormones (thyroxine, Km = 3.0 microM and triiodothyronine, Km = 2.7 microM), reflecting hepatic multispecificity. LST-1 is probably the most important transporter in human liver for clearance of bile acids and organic anions because hepatic levels of another organic anion transporter, OATP, is very low. This is also the first report of the human molecule that transports thyroid hormones.

Immunohistochemical distribution and functional characterization of an organic anion transporting polypeptide 2 (oatp2)

The rabbit polyclonal antibody against rat organic anion transporting polypeptide 2 (oatp2) was raised and immunoaffinity-purified. Western blot analysis for oatp2 detected two bands ( 74 and 76 kDa) in rat brain and a single band (76 kDa) in the liver. By immunohistochemical analysis, the oatp2 immunoreactivity was specifically high at the basolateral membrane of rat hepatocytes. Functionally, the oatp2-expressing oocytes were found to transport dehydroepiandrosterone sulfate, delta1 opioid receptor agonist [D-Pen2,D-Pen5]enkephalin, Leuenkephalin, and biotin significantly, as well as the substrates previously reported. These data reveal the exact distribution of the rat oatp2 at the protein level in the liver, and that oatp2 appears to be involved in the multispecificity of the uptaking substrates in the liver and brain.

Molecular characterization and tissue distribution of a new organic anion transporter subtype (oatp3) that transports thyroid hormones and taurocholate and comparison with oatp2

Two complementary DNAs for the organic anion transporter subtypes oatp2 and oatp3, which transport thyroid hormones as well as taurocholate, were isolated from a rat retina cDNA library. The sequence of oatp2 is identical to that recently reported (Noé, B., Hagenbuch, B., Stieger, B., and Meier, P. J. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 10346-10350), whereas the sequence of oatp3 is novel. oatp3 consists of 670 amino acid residues and exhibits a structural architecture common to the organic anion transporter family, possessing the 12 putative membrane-spanning segments. Oocytes injected with oatp2 and oatp3 cRNAs showed taurocholate uptake in a saturable manner. The oatp2 and oatp3 cRNA-injected oocytes also showed significant uptake of both thyroxine and triiodothyronine. Northern blot and in situ analyses showed that the oatp2 mRNA was widely expressed in neuronal cells of the central nervous system, especially in the hippocampus, cerebellum, and choroid plexus as well as in the retina and liver. The oatp3 mRNA was highly expressed in the kidney and moderately abundant in the retina. This suggests that oatp2 and oatp3 are multifunctional transporters involved in the transport of thyroid hormones in the brain, retina, liver, and kidney.