Nd:YAG laser in treatment of rectal cancer. Are there features predicting a curative result?

In the present study we report the results of Nd:YAG laser treatment in 36 patients with rectal carcinoma in whom negative biopsies were obtained at the end of the treatment. The laser (100-W maximal power output) was applied through a flexible endoscope during 20- to 40-min sessions repeated every three days until the lesion was destroyed completely. Follow-up examinations, including endoscopy with biopsies, liver and endorectal ultrasonography and chest x-ray were performed every three months during the first year and thereafter once a year. Between 1980 and 1991, 272 patients were treated. All were unfit for surgery because of metastasis (78), recurrence after an other procedure (54), associated conditions, or old age (140). No circumferential tumors of any size were obliterated, but among the 139 patients presenting with a noncircumferential lesion less than 7 cm in diameter, negative biopsies were obtained after laser treatment in 36 patients (26%). Of these 36 patients, eight had been treated previously by surgery (5) or radiotherapy (3). Mean follow-up is 37 months (range 12-71). Recurrences were observed in four cases. Seven patients died during the study but only one death was related to the cancer (pelvic extension 19 months after treatment). Endorectal ultrasonography was performed prior to treatment in 15 patients and showed no invasion of the rectal wall deeper than the submucosa. After treatment, endorectal ultrasonography in 22 patients showed significant changes corresponding to cicatricial pattern in 60% of controlled patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Gallbladder dyskinesia and manometry of Oddi's sphincter]. / Gallenblasendyskinesie und Manometrie des Sphinkter Oddi.

Sphincter of Oddi activity partly regulates bile flow into the small intestine. This regulation is mainly controlled by phasic contractions and basal tone of the sphincter, together with gallbladder contraction. Manometric studies of the sphincter have permitted a better understanding of its physiological role and implication in biliary dyskinesia symptoms. Motility abnormalities of Oddi's sphincter present classically as bouts of recurrent pain and/or idiopathic pancreatitis, that can be successfully cured by endoscopic sphincterotomy.

Microscopic examination of bile directly collected during endoscopic cannulation of the papilla. Utility in patients with suspected microlithiasis.

The usefulness of microscopic examination of pure bile directly collected from the biliary tract during endoscopic retrograde cholangiography and without hormonal simulation was prospectively evaluated in 72 patients. According to clinical, biochemical, ultrasonographic, and radiographic data, the patients were separated into two groups: group 1, patients with proven stones (N = 50), and group 2, patients with suspected microlithiasis presenting symptoms suggestive of cholelithiasis but without evidence of macroscopic stones at echography or cholangiography (N = 22). Cholesterol crystals and/or bilirubinate granules were observed (eg, positive examination) in the bile of 41 of the 50 patients of group 1 (82%). Among patients of group 2, seven (32%) had a positive bile examination: cholecystectomy (N = 2) or endoscopic sphincterotomy (N = 5) disclosed minute stones in all cases. In the 15 patients of group 2 with a negative bile examination, cholecystectomy (N = 3), sphincterotomy (N = 2), and clinical (and/or echographic) 20-month follow-up (N = 9) revealed biliary lithiasis in only one patient, in whom recurrent cholangitis led to disclosure of one bile duct stone. According to these results, microscopic examination of bile samples collected during endoscopic retrograde cholangiography exhibited a sensitivity and a specificity for cholelithiasis recognition of 82.7% and 100%, respectively, with a positive predictive value of 88%. We conclude that the accuracy of this method makes it useful to investigate and manage patients with suspected microlithiasis.

Putrescine and spermidine uptake is regulated by proliferation and dexamethasone treatment in AR4-2J cells.

Polyamines are essential for cell growth and differentiation. Their specific uptake contributes to the regulation of intracellular polyamine levels. In this study, we describe the modulation of this transport mechanism in a rat tumoral pancreatic acinar cell line (AR4-2J) and analyze the transport system characteristics of the normal rat pancreatic acini. Normal acini had a common carrier for spermidine and spermine, like AR4-2J cells, but not a specific putrescine carrier. Intracellular polyamine deprivation enhanced putrescine and spermidine uptake of AR4-2J cells with no modification of polyamine carrier affinity. Uptake was modulated during growth and decreased for both polymaines at confluence. AR4-2J cell differentiation with dexamethasone prevented cell proliferation and diminished uptake of both putrescine and spermidine without affecting their respective carrier affinities. Our data show, first, that the polyamine transport system could be modulated by polyamine metabolism with no change in its affinity characteristics. Second, in rat pancreatic acinar cells, neoplastic transformation was partly characterized by induction of a high-affinity putrescine carrier. This phenotype was not reversed by dexamethasone-induced cell differentiation.

Characterization of putrescine- and spermidine-transport systems of a rat pancreatic acinar tumoral cell line (AR4-2J).

Polyamines are polycationic molecules essential for cell growth and differentiation. Recent work has focused on cell polyamine-transport systems as a way to regulate intracellular polyamine levels. In this study, we demonstrate the presence of two different active transporters for putrescine and spermidine in a rat tumoral cell line (AR4-2J). The first has a Km of 3.1 microM and a Vmax of 3.7 pmol/15 min per micrograms of DNA for putrescine and the second a Km of 0.42 microM and a Vmax of 4.7 pmol/15 min per micrograms of DNA for spermidine. Competition studies performed between the polyamines confirm the difference between these two carriers; one has an equal affinity for the three main polyamines, and the other has a lower affinity for putrescine. Amino acids do not share this transport system, which is Na(+)-independent. Choline chloride inhibits selectively and in a dose-responsive manner the uptake of putrescine without affecting that of spermidine. These data demonstrate that AR4-2J cells possess two polyamine transporters; one is specific for aminopropyl groups (spermidine and spermine), and the other is choline-sensitive, but cannot discriminate between aminobutyl (putrescine) and aminopropyl groups.

Gastrin modulates growth of a rat acinar pancreatic cell line: receptor analysis and signal transduction.

Recent studies have demonstrated the presence of both CCKA and CCKB receptors on dog and guinea pig pancreas. Although CCKA receptors are implicated in enzymatic secretion, biological effects of CCKB receptors are still unknown. We have previously found that a rat acinar pancreatic cell line (AR4-2J) possesses both receptor subtypes. In this work we report the ability of various CCK/gastrin agonists and antagonists to bind with these receptors. We found that gastrin, pentagastrin and Gastrin/CCK4 induce ornithine decarboxylase activity, an early event involved in cell proliferation, as well as 3H-thymidine incorporation. Furthermore, these effects occur at doses at which these peptides interact only with the CCKB receptor subtype. In view of these data we propose that modulation of AR4-2J cell growth by gastrin agonists specifically involve occupation of the CCKB receptor.

Exocrine pancreatic nodules after longterm pancreaticobiliary diversion in rats. An effect of raised CCK plasma concentrations.

Surgical diversion of bile and pancreatic secretions to the mid small bowel has been shown to provoke increased CCK plasma concentration and growth of the pancreas in rats. This study was undertaken to investigate the effects of chronic pancreaticobiliary diversion on pancreatic morphology as well as the circulating concentrations of pancreatic polypeptide, secretin, gastrin, and CCK. Fifteen month diversion provoked 73 and 86% increases in pancreatic weight and volume (p less than 0.001). Cholecystokinin blood concentration increased by 98%, from 20.9 +/- 5.7 pg/ml in controls to 41.3 +/- 5.4 after diversion (p less than 0.05), but pancreatic polypeptide, secretin, and gastrin levels were not affected. The volume of the exocrine pancreas doubled from 1104.6 +/- 78.2 mm3 in controls to 2201.2 +/- 229.2 (p less than 0.001), with a matching increase in interstitial tissue. On the contrary, the volume of the endocrine pancreas remained unchanged. Hyperplastic nodules developed in the exocrine pancreas, in 71% of diverted rats, but not in transected controls. We conclude from these observations that chronic diversion of bile and pancreatic juice stimulated pancreatic growth, most likely through a persistent rise of CCK plasma concentrations. Furthermore, this long lasting stimulation induced the development of exocrine pancreatic nodules.