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PubMed1983

[Effect of moderate local hyperthermia in combination with chemotherapy with cyclophosphamide or N-nitroso- 1,3-bis(2-chloroethyl)urea(BCNU) on Yoshida sarcoma implanted in the descending colon of rats. 1. Repeated hyperthermia within 8 days and combination of chemotherapy followed by hyperthermia 24 h later].

The application of hyperthermia in cytostatic therapy has been discussed for a long time. Recently the question arose whether the chances of therapy might be improved by combining chemotherapy with hyperthermia. We used an inoculated gastrointestinal tumor to verify this hypothesis experimentally. 2 X 10(6) Yoshida sarcoma ascites cells were implanted in the descending colon of 101 Sprague-Dawley rats. A preternatural anus with two lumina was established concomitantly. Chemotherapy started on day 6 after surgery. 24 h later local hyperthermia was applied by means of a silicone tube inserted in the immobilized descending colon. The temperature in the tumor was raised to 43 +/- 0.5 degrees C. No acute toxic effects of hyperthermia were noted. The body temperature was kept from rising above normal by cooling. The differences in survival time between the chemotherapeutically treated groups and the control group were statistically validated. Additional hyperthermia did not result in additive effects. No advantage of hyperthermia alone was noted over the control. The results support scepticism about the therapeutic efficacy of hyperthermia and underline the necessity of further investigations in clinically adapted animal experiments.

Animals↗
PubMed2006

Endolaparoscopic left hemicolectomy and synchronous laparoscopic radical nephrectomy for obstructive carcinoma of the descending colon and renal cell carcinoma.

Colorectal self-expandable metal stents (SEMS) have been used successfully as preoperative bridges to surgery for obstructive left-sided colorectal carcinoma. Endoscopic relief of the obstruction allows for full bowel preparation and accurate preoperative staging. A laparoscopic approach, considered by many to be contraindicated in the presence of obstruction, becomes feasible after endoscopic decompression. We present a case of obstructive carcinoma of the descending colon successfully treated with endoscopic decompression with colorectal SEMS. Subsequent staging with computed tomography revealed a renal cell carcinoma in the left kidney. Synchronous laparoscopic resection of the two carcinomas was performed, with no morbidity. To the best of our knowledge, this is the first report of endolaparoscopic left hemicolectomy and synchronous laparoscopic radical nephrectomy for obstructive carcinoma of the descending colon and renal cell carcinoma. The advantages of colorectal SEMS and the endolaparoscopic approach in managing obstructive colorectal carcinoma are discussed.

Aged, 80 and over↗
PubMed1999

Antegrade continence enema for the treatment of fecal incontinence in adults: use of gastric tube for catheterizable access to the descending colon.

PURPOSE: We describe the use of a gastric segment in performing the antegrade continence enema procedure in patients with refractory fecal incontinence. MATERIALS AND METHODS: The antegrade continence enema procedure was performed in 4 women and 3 men with refractory neurogenic fecal incontinence. Preoperative evaluation included defecography and anorectal manometry. Operative technique involves tunneling a 10 cm. segment of tubularized stomach isolated along the greater curve with preservation of the right gastroepiploic vessels through the anterior tenia of the colon just distal to the splenic flexure. After the stoma is mature the patient passes a catheter and runs 1 to 2 l. warm tap water through it while seated on the toilet. Digital stimulation may be required to initiate bowel emptying and irrigation is continued until clear. RESULTS: Creation of a nonrefluxing catheterizable gastric tube to the descending colon was successful in all 7 patients. At a mean postoperative followup of 22.4 months all patients are continent and use antegrade continence enema irrigation every other day on average. One patient required early revision because of stomal stenosis. Special measures include application of a generic antacid tablet to the stoma and use of a skin barrier. CONCLUSIONS: Catheterizable access to the descending colon for the antegrade continence enema procedure more closely approximates normal defecation patterns by emptying ("unloading") the left side of the colon. The stomach is a suitable option in close proximity for this purpose and is especially advantageous when the appendix is not available. The antegrade continence enema procedure using a gastric segment can be safely and effectively performed, and is well suited for use by reconstructive surgeons who are familiar with the Mitrofanoff principle.

Adult↗
PubMed1979

Epithelial cell kinetics in the descending colon of the rat.

Epithelial cell kinetics were investigated in the descending colon of the rat. The number of cells per crypt was found to be approximately 625, with 33 cells per cell column and 19 cell columns per crypt circumference. The growth fraction of the colonic crypt was 0.42, and proliferating cells were situated largely in the lower half of the crypt. The cell cycle time was 50.5 h, with values for the G1, S and G2 phases of 40.0, 7.6 and 2.9 h respectively. Cell migration studies showed that it took 60-72 h for a cell to migrate from the upper border of the proliferative cell compartment in the crypt to the luminal surface of the colon. Data were also obtained from continuous labelling with tritiated thymidine and from studying the circadian rhythm of proliferative activity, which suggest that the cells in the bottom of the crypt may constitute a separate, more slowly cycling (stem)cell compartment.

Animals↗
PubMed1985

Apical membrane potassium and chloride permeabilities in surface cells of rabbit descending colon epithelium.

The apical membranes of surface cells in the rabbit descending colon possess a significant ionic conductance in parallel to amiloride-blockable Na+ channels. The identity of the ion(s) responsible for the amiloride-insensitive conductance is unknown. The purpose of the present paper was to assess the permeability and net driving forces for K+ and Cl- across this membrane using conventional and ion-sensitive micro-electrode techniques. Intracellular Cl- activity (aiCl) averaged 23 +/- 2 mM with an equilibrium potential (ECl) of -38 +/- 2 mV. This value is less than previous estimates of the electromotive force (e.m.f.) of the amiloride-insensitive pathway (ca. -50 mV). Consequently, Cl- alone cannot account for the amiloride-insensitive conductance. Replacement of Cl- by gluconate in the serosal solution decreased aiCl to 17 +/- 2.8 mM. aiCl was lowered to approximately 1 mM by replacement in the mucosal bath or by replacement in both solutions. The results indicate a low Cl- conductance in the basolateral membrane, in agreement with previous electrophysiological studies of this epithelium. In contrast to Cl-, the chemical driving force for K+ was large enough to support the e.m.f. of the amiloride-insensitive pathway (K+ equilibrium potential, EK = -66 mV). The basolateral membrane potential (Vbl), EK and the intracellular K+ activity (aiK) were decreased in parallel following inhibition of the basolateral Na-K pump, providing evidence that Vbl is largely due to a K+ diffusion potential. In the presence of serosal 10(-4) M-ouabain, aiK appeared to remain above equilibrium and more than doubled after addition of Ba2+ to the serosal bath. Replacement of the mucosal bathing solution with KCl or gluconate Ringer solution largely restored Vbl and the transepithelial potential (VT) in tissues which had been previously treated with ouabain. The restoration of VT was decreased and the transepithelial resistance (RT) was increased by addition of tetraethylammonium to the mucosal bath. The above results suggest that there are at least four routes for ion movement across the apical membrane of rabbit colon surface epithelial cells. These are: (1) an amiloride-sensitive Na+ channel, (2) a K+ conductance, (3) electroneutral uptake of Cl- from lumen to cell interior and (4) an active K+ transport mechanism, also from lumen to cell interior.

Animals↗
PubMed1984

Ion transport by rabbit descending colon: mechanisms of transepithelial potassium transport.

In vitro preparations of rabbit descending colon were studied under steady-state short-circuit conditions to determine 1) the K concentration dependence of unidirectional K fluxes; 2) the effects of the K channel blocker barium and the diuretic agent furosemide; and 3) the steady-state tissue specific activity of 42K when added to the luminal bathing solution. Results from these studies reveal that 1) labeling of cellular K from the mucosal solution is less than 25% of that from the serosal solution; 2) both unidirectional K fluxes are composed of saturable and nonsaturable components; 3) the serosal-to-mucosal saturable component is abolished by ouabain, and subsequent addition of 2,4-dinitrophenol abolishes the saturable component of the mucosal-to-serosal K flux; 4) luminal or serosal barium alters K transport in a manner consistent with the presence of barium-sensitive K conductances at both membranes; 5) luminal furosemide did not alter K transport; and 6) there is no shunt selectivity for K. We conclude that the majority of both unidirectional K fluxes follow a transcellular pathway and that both the apical and basolateral membranes possess active K uptake mechanisms and barium-sensitive K exit mechanisms.

2,4-Dinitrophenol↗
PubMed1993

Mechanisms of the secretory response to luminal propionate in rat descending colon in vitro.

Short chain fatty acids stimulate Cl secretion in rat descending colon in vitro via an enteric reflex involving mucosa and cholinergic nerves. We used the short circuit current as the measure of Cl secretion caused by Na propionate (NaP) (0.5 mM) in luminal bath fluid and studied the mechanism of the response. The NaP response was decreased 81% by atropine and 76% by lidocaine. It was unaffected by tetrodotoxin, omega-conotoxin or by tachyphylaxis to capsaicin, CGRP, substance P, histamine or PGE2. It was not reduced by inhibitors of 5-HT2 or 5HT3 receptors or by partial tachyphylaxis to 5-HT. However, superficial mucosal injury with hypertonic Na sulfate (2 M) or xylose (4.5 M) reduced the NaP response by 90% and 86%, respectively, and mucosal concanavalin A (1 mg/ml) reduced it by 73%. Neither piroxicam (10 microM) nor nordihydroguaretic acid (10 microM) affected the NaP response. We hypothesize that NaP stimulates the superficial epithelium to release an unidentified agonist that depolarizes predominantly cholinergic nerve terminals and causes colonic secretion.

Acetylcholine↗
PubMed1979

Necessity for end colostomy with transection of the descending colon in guinea pigs.

Surgical procedures for resection and transection of the descending colon in the guinea pig were studied. Wedge resection with removal of less than 1 cm diameter of tissue resulted in an 80% (8 of 10 guinea pigs) survival rate. Colonic transection with restorative anastomosis, either end-to-end or side-to-side, resulted in a 94% (35 of 37 guinea pigs) death rate due to colonic impaction proximal to the site of anastomosis. A modified procedure for ventral end colostomy resulted in a 79% (19 of 24 guinea pigs) survival rate. These results indicated that caution should be taken in surgical manipulations intended to treat or study diseases of the colon in the guinea pig.

Animals↗
PubMed1980

Lymphatic cyst of the descending colon: a report of a case.

A patient with a lymphatic cyst of the descending colon, treated by segmental colon resection, is reported. Lymphatic cysts of the colon are extremely rare, and there have been only fourteen previously reported cases. In no case has the diagnosis of lymphatic cyst of the colon been made prior to the excision of the lesion.

Aged↗
PubMed1981

Potassium transport by rabbit descending colon, in vitro.

Studies of the bidirectional fluxes of K across segments of rabbit descending colon indicate that: a) when the tissue is short-circuited, the net flux does not differ significantly from zero under control conditions and in the presence of aldosterone; and b) the bidirectional fluxes of K conform to the Ussing flux-ratio equation over a wide range of transepithelial electrochemical potential differences. These and other findings strongly suggest that the movements of K across the epithelium are restricted to paracellular routes and are entirely passive. Studies dealing with the mechanism of homocellular K transport indicate that: a) K is actively transported into the cells across the basolateral membranes against an electrochemical potential difference of approximately 30 mV; and b) the active uptake of K may be mediated by a rheogenic Na-K exchange pump that is also responsible for transcellular Na transport. These results are entirely consistent with the model proposed by Koefoed-Johnson and Ussing for isolated frog skin.

Aldosterone↗
PubMed1992

Endothelin-1 stimulates chloride and potassium secretion in rabbit descending colon.

The vasoactive peptide endothelin-1 (ET-1) which is present in high concentrations in the colon, causes concentration-dependent electrogenic Cl- secretion in rabbit descending colon. This effect is half-maximal at 0.11 mumol/l. Like other secretagogues, ET-1 also stimulates K+ secretion. The secretory effect of ET-1 is associated with increased release of prostaglandin E2 from the serosal surface of the mucosa. ET-1-induced Cl- secretion is completely inhibited by the loop diuretic bumetanide and by indomethacin and quinacrine, inhibitors of prostaglandin synthesis. Neuronal mechanisms do not seem to be involved, as tetrodotoxin did not affect the secretory response to ET-1 significantly. On the other hand, neither the catalytic activity nor the transport function of the Na+/K(+)-ATPase of rabbit colon epithelium is affected by endothelin-1 (ET-1) in concentrations up to 10 mumol/l. It is concluded that ET-1 causes Cl- and K+ secretion by stimulating phospholipase A2 and release of prostaglandins, whereas Na+ transport is not altered.

Animals↗
PubMed1979

Active and passive properties of rabbit descending colon: a microelectrode and nystatin study.

The electrical properties of the basolateral membrane of rabbit descending colon were studied with microelectrode methods in conjunction with the polyene antibiotic nystatin. Two problems were examined: (i) the relative distribution of tight junctional, apical membrane and basolateral membrane resistances, and (ii) the ionic basis of the basolateral membrane potential. Intracellular K+ activity (K+) was measured using liquid ion exchanger microelectrodes ((K+) = 76 +/- 2 MM) and was found not to be in equilibrium with the basolateral membrane potential. In order to measure membrane resistances and to estimate the selective permeability of the basolateral membrane, the apical membrane was treated with nystatin and bathed with a K2SO4 Ringer's solution which was designed to mimic intracellular K+ composition. This procedure virtually eliminated the resistance and electromotive force of the apical membrane. Shunt resistance was calculated by two independent methods based on microelectrode and transepithelial measurements. Both methods produced similar results (Rs = 691 +/- 63 omega cm2 and 770 +/- 247 omega cm2, respectively). These findings indicate that the shunt has no significant selectivity, contrary to previous reports. Native apical membrane resistance was estimated as 705 +/- 123 V cm2 and basolateral membrane resistance was 95 +/- 14 V cm2. To estimate basolateral membrane selectivity, the serosa was bathed in a NaCl Ringer's solution followed by a series of changes in which all or part of the Na+ was replaced by equimolar amounts of K+. From measures of bi-ionic potentials and conductance during these replacements, we calculated potassium permeability and selectivity ratios for the nystatin-treated colon by fitting these results to the constant field equations. By correcting for shunt conductance, it was then possible to estimate the selective permeability of the basolateral membrane alone. Selectivity estimates were as follows: PNa/PK = .08 and PCl/ PK = .07 (uncorrected for shunt) and PNa/PK = .04 and PCl/PK = .06 (basolateral membrane alone). In a second set of experiments, evidence for an electrogenic Na+ pump in the basolateral membrane is presented. A small ouabain-sensitive potential could be generated in the nystatin-treated colon in the absence of chemical or electrical gradients by mucosal, but not serosal, addition of NaCl. We conclude that this electrogenic pump may contribute to the basolateral membrane potential; however, the primary source of this potential is "passive": specifically, a potassium gradient which is maintained by an "active" transport process. An appendix compares the results of nystatin experiments to amiloride experiments which were conducted separately on the same tissues. The purpose of this comparison was to develop a comprehensive model of colonic transport. The analysis reveals a leak conductance in the apical membrane and the presence of an amiloride-insensitive conductance pathway.

Animals↗
PubMedDate not supplied

Leiomyoma of Meckel's diverticulum associated with adenocarcinoma of the descending colon.

A case of leiomyoma of Meckel's diverticulum associated with a carcinoma of the descending colon, presenting with intestinal obstruction, is described. Only two cases of smooth muscle tumors of the small intestine associated with carcinoma of the large bowel have been described so far, and ours is probably the first case of its kind to be reported. The importance of angiography and a through intraoperative exploration is stressed.

Adenocarcinoma, Mucinous↗
PubMed1984

Effects of histamine and histamine receptor antagonists on ion transport in rabbit descending colon.

The effects of histamine on colonic ion transport were examined in in vitro preparations of rabbit descending colon. Serosal addition of histamine (10(-5) M) produced a transient increase in short-circuit current (Isc) and transepithelial conductance. The Isc response to histamine could be blocked by removing Cl from both bathing solutions, adding furosemide (10(-3) M) to the serosal bathing solution, adding indomethacin to the serosal and mucosal bathing solutions (10(-5) M), or removing Ca from the serosal bathing solution. In addition, the histamine-induced increase in Isc was inhibited in a dose-dependent manner by the H1-receptor antagonist diphenhydramine, with a maximal inhibition at 10(-4) M and a half-maximal inhibition at 3 X 10(-7) M. The H2-receptor antagonist cimetidine (10(-3) M) was without effect on the histamine response. Measurement of unidirectional Na, K, and Cl fluxes revealed that serosal addition of diphenhydramine (10(-3) M) reduced basal Isc due to a decrease in mucosal-to-serosal Na flux. Serosal addition of diphenhydramine (10(-3) M) also inhibited the increase in Isc produced by serosal addition of prostaglandin E1, 8-bromo-cAMP, cholera toxin, or the ionophore A23187. Measurement of unidirectional K and Cl fluxes revealed that prostaglandin E1 alone increased serosal-to-mucosal K and Cl fluxes and reduced the mucosal-to-serosal K flux, thereby increasing net K and Cl secretion. Serosal diphenhydramine (10(-3) M) abolished the changes in Cl fluxes produced by prostaglandin E1 and reduced the magnitude of the changes in K fluxes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Primary descending colon lymphoma: case communication].

Primary colon lymphomas are very uncommon gastrointestinal tumors, more so in the descending colon. We would like to present this clinical entity with the case of a 33-year-old woman in order to inform them about the case of Primary colon lymphoma that was encountered and to review the literature. In her case, the diagnosis was suspected from the clinical symptoms, images and fiber endoscopy study. The diagnosis was confirmed by anatomopathology and inmunohistoquimic study. The woman was subjected to exploratory laparotomy and the final diagnosis was given to be high-grade MALT type Lymphoma B cells (Non-Hodgkins Lymphoma Big Cell) big cells) EII2.

Adult↗
PubMed2005

Propulsive activity induced by sequential electrical stimulation in the descending colon of the pig.

UNLABELLED: This work was performed to study electrically induced contractions in the descending colon of pigs. Contractions were monitored using impedance planimetry and manometry. The luminal pressure, cross-sectional area (CSA), latency and velocity of CSA decrease were compared when using 3 ms, 9, 12, 15 or 30 mA pulses at 10 Hz for 10 s, and 15 mA, 0.03, 0.3 or 3 ms pulses at 10 Hz for 10 s. Stimulation was performed prior and after the application of N(G)-nitro-L-arginine methyl ester (L-NAME) and atropine. In the untreated colon, contraction was always of an 'off' type. A current increase from 9 to 30 mA increased the pressure. An increase of pulse duration from 0.03 to 3 ms shortened the latency, accelerated contraction and increased pressure. By sequential stimulation, contractions were coordinated to propel semi-fluid and solid luminal contents. L-NAME increased the magnitude of CSA decrease. Atropine induced inhibitory effects on contractions elicited by 3 ms pulses and abolished contractions induced by 0.03 and 0.3 ms pulses. IN CONCLUSION: (i) electrical stimulation evokes'off' colon contractions, which can be coordinated to result in propulsion; (ii) the best combination for current and pulse duration to induce propulsive contractions is 15 mA and 3 ms; (iii) nitrergic and cholinergic pathways mediate responses to electrical stimulation.

Animals↗
PubMedDate not supplied

Adrenergic factors involved in the control of crypt cell proliferation in jejunum and descending colon of mouse.

The mitotic rates in the crypts of Lieberkühn of the proximal jejunum and descending colon of mouse, following different treatments, were measured using a stathmokinetic technique. Regression coefficients, representing mitotic rates, were then calculated by the method of least squares. Treatment with adrenaline, isoprenaline, phenylephrine, phentolamine, and yohimbine all resulted in decreased mitotic rate of jejunal and colonic crypt cells. Chemical sympathectomy and cryosympathectomy had a similar effect, and chemical sympathectomy was followed by a supersensitivity to clonidine. Intraperitoneal injection of metaraminol, clonidine, propranolol, prazosin, labetolol and simultaneous injection of propranolol and adrenaline all resulted in an increased rate of crypt cell proliferation in both jejunum and colon. A significant increase in mitotic rate was observed in both tissues at night. The amplitude of this diurnal variation was decreased in both jejunum and colon following chemical sympathectomy. In addition, the amplitude of this variation in jejunum was decreased after treatment with yohimbine or phentolamine. The results of the study suggest that the sympathetic nervous system stimulates epithelial cell proliferation in both the small and large intestine and that this effect is mediated by an alpha 2-adrenoceptor. By contrast, stimulation of alpha 1- and beta-adrenoceptors is inhibitory to cell proliferation in these tissues.

Animals↗