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PubMed1991

[Enzymatic ligation of DNA fragments containing phosphoamide modification of the internucleotide bonds].

DNA fragments with the point amidophosphate (cyclohexylamido- or morpholido-) modification in the sugar-phosphate backbone were synthesized and separated into individual diastereoisomer. The isomers were separated by the reversed-phase HPLC (RPC), and chirality at phosphorus was assigned by a stereochemical correlation scheme using phosphorothioate standards. The RPC-retention time values for Rp-isomers were found to be lower than for Sp-analogues. Amidophosphate DNA fragments were used as P- and OH-components in the T4 DNA-ligation. The enzyme does not ligate amidated fragments with modified internucleotide linkage near 5'- or 3'-end, independently of the amidophosphate chirality. When an unmodified phosphodiester linkage separates the amidophosphate group from 3'-end in O-component, the ligation occurs only with Sp-isomer, whereas Rp-analogue does not give the ligation product. In the P-component of the ligation, configuration of the modified linkage separated from 5'-phosphate by an unmodified linkage does not affect the result of the enzymatic reaction: both Sp-and Rp-stereomers do take part in the ligation. As a result of the ligation of the modified fragments on unmodified templates a set of 31-mers was obtained. They contain FokI and EcoRI recognition sites with the cleavage points of both endonucleases coinciding and being amidated. Upon treatment of duplex DNA consisted of unmodified and amidated strands with these endonucleases Sp-configuration did not hinder the cleavage of the unmodified strand, whereas Rp-configuration inhibited the EcoRI and did not affect the FokI cleavage.

Base Sequence↗
PubMed1986

Lymphangiographic evaluation of experimentally induced chylothorax after ligation of the cranial vena cava in dogs.

Ligation of the cranial vena cava (CrVC) distal to the entrance of the azygous vein resulted in chylothorax in 7 of 10 dogs. Of the remaining 3 dogs, 1 developed a serosanguineous effusion that did not become chylous, and 2 dogs did not develop pleural effusion. In 2 of the 7 dogs developing chylothorax, the pleural effusion became serosanguineous within 2.5 weeks after CrVC ligation. Mesenteric lymphangiography was performed 2 to 6 weeks after ligation of the CrVC. Lymphangiectasia was seen in 4 dogs with chylothorax, but was not seen in the 3 dogs with serosanguineous effusions or the 2 dogs that did not develop effusions. One dog with chylothorax died prior to repeat lymphangiography. Less dye entered the thoracic duct, and alternate lymphaticovenous communications to the caudal vena cava were evident in the dogs without chylothorax. Ligation of the thoracic duct at the lymphaticovenous junction was performed in 3 dogs. These dogs did not develop pleural effusion. Lymphangiography was performed immediately after ligation and indicated filling of abdominal lymphatics but not of the thoracic duct. Lymphangiographic findings 6 weeks after ligation also indicated filling of intestinal lymphatics. Results of the present study indicated that ligation of the CrVC causes chylothorax, and that thoracic lymphangiectasia is a consistent finding in animals with experimental chylothorax. Obstruction of the thoracic duct did not induce lymphangiectasia or chylothorax. Impedence of thoracic duct flow into the CrVC may be a cause of clinical chylothorax in the dog.

Animals↗
PubMed1980

Kinetics of ligation of fibrin oligomers.

Human fibrinogen was treated with thrombin in the presence of fibrinoligase and calcium ion at pH 8.5, ionic strength 0.45, and the ensuring polymerization was interrupted at various time intervals (t) both before and after the clotting time (tc) by solubilization with a solution of sodium dodecyl sulfate and urea. Aliquots of the solubilized protein were subjected to gel electrophoresis on polyacrylamide gels after disulfide reduction by dithiothreitol and on agarose gels without reduction. The degree of gamma-gamma ligation was determined from the former and the size distribution of ligated oligomers, for degree of polymerization x from 1 to 10, from the latter. The degree of gamma-gamma ligation was calculated independently from the size distribution with the assumption that every junction between two fibrin monomers remaining intact after solubilization is ligated, and this agreed well with the direct determination. The size distribution at t/tc = 1.3 to 1.6 differed somewhat from that calculated by the classical theory of linear polycondensation on the assumption that all reactive sites react with equal probability and rate. Analysis of the difference suggests that ligation of a fibrin digomer is not a random process; the probability of ligation of a given junction between two monomers increases with the oligomer length. The number-average degree of polymerization, xn, of ligated oligomers increases approximately linearly with time up to a value of 1.6.

Binding Sites↗
PubMed1993

Increased neutrophil function induced by bile duct ligation in a rat model.

Neutrophil function was studied in rats with common bile duct ligation. Superoxide production stimulated by phorbol myristate acetate, opsonized zymosan or formyl-methionyl-leucyl-phenylalanine; phagocytosis; and chemotaxis were significantly greater in neutrophils from rats with common bile duct ligation than in sham-operated control rats. Enhanced neutrophil activity was observed within 12 hr of bile duct ligation; it remained increased during the 15-day study. Preincubation of neutrophils from control rats with sera of rats with common bile duct ligation did not increase superoxide generation. This suggests that the high superoxide production observed in neutrophils of rats with common bile duct ligation was not an immediate effect of the serum. Neutrophils of rats with portal vein ligation exhibited normal activity, indicating that portal systemic shunting per se is not the underlying mechanism for increased activity. The elevated levels of AST and alkaline phosphatase, indicating liver damage, that appeared within 12 hr of bile duct ligation correlated with the increased superoxide generation.

Animals↗
PubMed1995

The role of increased nitric oxide in the vascular hyporeactivity to noradrenaline in long-term portal vein ligated rats.

To test the possible role of nitric oxide production in long-term portal vein ligation in the rat, where the hyperdynamic circulation was reported to be absent, in vivo experiments on isolated thoracic aortic rings from partial portal vein ligated or sham-operated rats were performed, 6 months postoperatively. The concentration-response curves to noradrenaline of both intact and endothelium-denuded rings from portal hypertensive rats were significantly shifted to the right as compared to those from sham-operated animals. In intact rings, addition of NG-nitro-L-arginine, a specific inhibitor of nitric oxide synthase, resulted in a significant shift of the curves to the left in sham-operated and portal vein ligated rats. In endothelium-denuded rings, addition of NG-nitro-L-arginine resulted in a significant shift of the curves to the left in portal vein ligated but not in sham-operated animals. After blockade of the nitric oxide biosynthesis with NG-nitro-L-arginine, the negative logarithm of the concentration of nonadrenaline causing half-maximal response did not significantly differ any more between portal vein ligated and sham-operated rats; in endothelium-denuded rings hyporeactivity to noradrenaline persisted in portal vein ligated rats. Only in the intact rings did NG-nitro-L-arginine significantly increase the maximal contractions. No differences were demonstrated in endothelium-dependent relaxations to acetylcholine between sham-operated and portal hypertensive animals. From these results, it can be concluded that in vitro aortic hyporeactivity to noradrenaline is still present in long-term portal vein ligated rats, and that it results at least partially from activation of the L-arginine: nitric oxide pathway in the aortic vascular wall.

Animals↗
PubMed1990

Effects of maternal bilateral ureteral ligation on the development of the proximal tubule of the kidney in fetal rats: morphometry and electron microscopic study.

Development of the proximal tubule in the fetal kidney was studied following ligation of both ureters of pregnant rats. The ligation was performed on days 15, 17, 19, and 21 of gestation and autopsy followed 24 hours after each operation. On fetal days 20 and 22, the proximal tubular length per unit volume (1 mm3) of whole kidney of the fetuses from the ligated mothers was significantly increased, while the ratio of total glomerular volume to total proximal tubular volume was remarkably decreased when compared to that of the fetuses from the non-ligated mothers. Apical vacuoles in proximal tubular cells were increased by the ligation on fetal days 20 and 22. These findings suggest that maternal bilateral ureteral ligation accelerates the growth and differentiation of the proximal tubule in fetal kidney, when the fetal kidney is functional in urine production.

Animals↗
PubMed1981

A randomized trial to compare rubber band ligation with phenol injection for treatment of haemorrhoids.

A prospective randomized trial has compared rubber band ligation with phenol injection in 82 patients with symptomatic haemorrhoids. The symptomatic results in all patients 12 months after treatment were indistinguishable, 64 per cent being improved after rubber band ligation, compared with 70 per cent after injection. Complications of treatment were recorded in 5 patients after rubber band ligation, 3 of whom required hospital admission compared with one minor complication after infection. However, repeated treatment was necessary in 13 patients after phenol injection compared with only 4 following rubber band ligation (P less than 0.05). Additional treatment was necessary in 6 patients from each group. Two-thirds of patients with third-degree piles required additional therapy. It is concluded that rubber band ligation and injection provide similar results, but rubber band ligation is more liable to complications with inexperienced operators.

Female↗
PubMed1977

Chronotropism and blood flow patterns following teratogenic doses of catecholamines in 5-day-old chick embryos.

In vivo heart rates of 5-day-old chick embryos were recorded from electrodes placed in close proximity to the heart. L-epinephrine (4X10(-10) mole), 1-norepinephrine (1X10(-9)mole) and 1-isoproterenol (1.6X10(-10)mole) in 5 microliter of isotonic saline transiently accerlerated the mean heart rate by almost 9 percent. L-phenylephrine (2X10(-9)mole/5microliter) and the experimental procedure produced no appreciable effect. The positive chronotropic effect of the catecholamines was found to be highly significant (P less than 0.0005) as computed by Student's t test. However, no direct relationship could be established between the chronotropic response and the aortic arch anomalies produced. A prolonged reduction of blood flow in the primitive heart tube and the sixth aortic arch after administration of epinephrine and isoproterenol is apparently related to the induction of hypoplastic right pulmonary artery with absent or hypoplastic right ductus arteriosus.

Abnormalities, Drug-Induced↗
PubMed1993

Intestinal migrating myoelectric complexes in rats with acute pancreatitis and bile duct ligation.

Intestinal migrating myoelectric complexes (MMC) were studied in rats subjected to common bile duct ligation. Four pairs of bipolar electrodes were implanted on the jejunum and the ileum of 21 rats. Animals were allowed to recover 7 days before electrical recordings were made. Bile duct ligation at the entrance to the duodenum (low) or above the pancreas (high) or sham operation was performed. MMCs were recorded before and 48 and 72 hr after the operation in each animal. MMC intervals were unchanged following high ligation or sham operation. However, 48 hr after low bile duct ligation, the MMC interval (20.6 +/- 2.5 min) was significantly prolonged compared with that before ligation (14.0 +/- 1.2 min). Further prolonged intervals (28.4 +/- 4.2 min) were observed 72 hr after the ligation. There were no significant differences among the slow wave frequencies in any group of animals, being in the range of 34.1 +/- 1.1 to 36.3 +/- 1.0 cycles/min. Thus, the MMC pattern in this rat model may be affected by the development of acute pancreatitis. The mechanism(s) responsible for altering the MMC pattern are not known; however, hepatic biliary secretion alone does not appear to play a primary role.

Acute Disease↗
PubMed1996

Ligation of portal vein branch induces DNA polymerases alpha, delta, and epsilon in nonligated lobes.

Ligation of a portal vein branch supplying 70% of the rat liver causes compensatory hypertrophy of the nonligated hepatic lobes with concomitant atrophy of the ligated lobes. To elucidate the mechanism of this response, the induction of the replication enzymes DNA polymerases alpha, delta, epsilon, as well as proliferating cell nuclear antigen (PCNA), were investigated in nonligated lobes after portal branch ligation. The induction patterns were compared with the well studied liver regeneration after 70% partial hepatectomy. DNA polymerases alpha, delta, and epsilon in the liver were extracted with 5 mM KCl (low-salt extract), then with 600 mM KCl (high-salt extract). DNA polymerases alpha, delta, and epsilon in low-salt extract were partially separated on a hydroxyapatite column and quantified. All enzyme activities in the nonligated lobes started to increase within 24 hr and reached maximum levels by 48 hr after portal branch ligation. These patterns were quite similar to those obtained with the remnant liver after partial hepatectomy. In low-salt extract, DNA polymerase delta and epsilon were prominent, while, in high-salt extract, largely DNA polymerases alpha and some activity of epsilon were recovered. PCNA was also induced after both portal branch ligation and partial hepatectomy, reaching maximum levels at 48 hr. From the similar changes in DNA polymerases and PCNA, our data indicate that portal branch ligation induces hepatocyte proliferation in the nonligated lobes in a way similar to partial hepatectomy.

Animals↗
PubMed1997

Cholesterol and bile acid metabolism after selective portal vein ligation.

AIM: To examine the regulatory effect of bile acid level on bile acid synthesis in the liver. METHODS: The portal branch perfusing left lateral and median lobes of the liver was ligated in rats and the activities of hepatic microsomal cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme of bile acid synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, and intrahepatic concentrations of cholesterol and bile acids were determined in the liver lobes deprived of and supplied with portal blood on Days 0, 1, 2, 4, and 7 after selective portal vein ligation (SPVL). RESULTS: In the portal vein (PV)-ligated lobes, liver weight decreased, hepatic cholesterol concentration was unchanged, and microsomal cholesterol concentration increased after SPVL. In the PV-nonligated lobes, liver weight increased, hepatic cholesterol concentration increased, and microsomal cholesterol concentration was unchanged. There were no significant differences in the activities of HMG-CoA reductase and cholesterol 7 alpha-hydroxylase among the PV-ligated and PV-nonligated lobes and the sham-operated controls. Intrahepatic bile acid level increased significantly in the PV-nonligated lobes for 4 days after SPVL, whereas those were essentially constant in the PV-ligated and the sham-operated control liver. Despite significant changes in the concentrations of intrahepatic cholesterol and bile acid, no significant correlations were observed between these concentrations and the activities of cholesterol 7 alpha-hydroxylase. CONCLUSIONS: SPVL causes atrophy and hypertrophy of the PV-ligated and nonligated liver lobes, respectively, without any significant changes in cholesterol and bile acid synthesis. Intrahepatic concentrations of bile acids and cholesterol have no regulatory effect on cholesterol 7 alpha-hydroxylase activity in the SPVL rat model.

Animals↗
PubMed1997

Clinical trial of prophylactic endoscopic variceal ligation for esophageal varices.

Endoscopic variceal ligation is an effective therapy for variceal bleeding, and use of the method has recently been increasing. We evaluated the clinical usefulness of prophylactic endoscopic variceal ligation. Twenty-two patients with enlarged, tortuous varices and "red color signs" were selected. These patients were treated with ligation therapy alone and the varices were eradicated, i.e., reduced to small, straight varices without red color signs. Ligation therapy was withdrawn if the general condition of the patient worsened or if the varices could not be removed by suction. Follow-up endoscopy was performed every 4 months, and another ligation was performed if there were recurrent varices or variceal bleeding. The total reduction rate was 86.4%, and eradication required two sessions of therapy and 30 days of hospitalization on average. Complications included esophageal injury in 1 patient and treatment-induced bleeding in 1 patient; both complications were easily controlled. No variceal bleeding occurred after the eradication. There was no mortality due to gastrointestinal bleeding during the median follow-up period of 346 days. Prophylactic endoscopic variceal ligation made it possible to prevent fatal variceal bleeding with a minimum risk of complications, suggesting that this could be an alternative method for the prevention of first-time variceal bleeding.

Adult↗
PubMed1988

Gastric diversion or pylorus ligation for gastric mucosal integrity and acid secretion studies in the rat?

The advantages of gastric diversion over pylorus ligation in rat gastric mucosal integrity and acid secretion studies over 6 hr were investigated. Mucosal injury developed in 80% of pylorus-ligation controls. Atropine (5 mg/kg) or cimetidine (40 mg/kg) had no effect on this injury (2.9 mm2 +/- 0.9 and 2.8 mm2 +/- 0.7, respectively, vs 3.1 mm2 +/- 1, mean +/- SEM, N = 10); however vagotomy increased it (13.7 mm2 +/- 1.5, mean +/- SEM, N = 10, P less than 0.001). Gastric diversion produced no mucosal injury. Pylorus-ligation H+ output was higher than that of gastric diversion (390.5 mumol +/- 54.8 vs 61 mumol +/- 2.5, mean +/- SEM, N = 10, P less than 0.001). Cimetidine (40 mg/kg) depressed H+ output of gastric diversion (21.3 mumol +/- 1.2 vs 61 mumol +/- 2.5, mean +/- SEM, N = 10, P less than 0.001), but not of pylorus ligation (424 mumol +/- 74.2 vs 390.5 mumol +/- 54.8, mean +/- SEM, N = 10). Vagotomy or atropine depressed pylorus-ligation H+ output (P less than 0.001), but each allowed an output (36.6 mumol +/- 5.5 and 120 mumol +/- 29, respectively, mean +/- SEM, N = 10) significantly (P less than 0.001) higher than that associated with it in gastric diversion (16 mumol +/- 1.4 and 17.1 mumol +/- 1.6, respectively, mean +/- SEM, N = 10). This study demonstrates that in the rat pylorus ligation, in contrast to gastric diversion, injures the gastric mucosa, stimulates H+ secretion, and overshadows the efficacy of antisecretory agents.

Animals↗
PubMed2001

Rubber band ligation for hemorrhoidal disease can be safely performed in select HIV-positive patients.

PURPOSE: Many surgeons have abandoned the use of rubber band ligation for the treatment of hemorrhoids in patients infected with human immunodeficiency virus because of the belief that this procedure could lead to disastrous outcomes. This study was designed to evaluate the safety and efficacy of rubber band ligation in otherwise healthy human immunodeficiency virus-positive patients. METHODS: A retrospective chart review of healthy human immunodeficiency virus-positive patients who underwent rubber band ligation for symptomatic hemorrhoids between April 1993 and May 2000 was conducted. RESULTS: The study group comprised 11 patients. All patients were male, with a median age of 48 (range, 32-64) years. Mean T-cell helper count was 450 (range, 200-1,000) cells/microl. A median of 2 (range, 1-4) rubber band ligations were performed per patient. The median length of follow-up was seven (range, 1-28) months. There were no deaths or complications in any study group patient. Eight patients (73 percent) had excellent results, with complete resolution of symptoms. Two patients (18 percent) had initial improvement but subsequently had hemorrhoidectomy because of recurrent symptoms. Only one patient (9 percent) had no benefit from rubber band ligation and underwent hemorrhoidectomy. CONCLUSION: These data suggest that asymptomatic human immunodeficiency virus-positive patients can be treated safely and effectively with rubber band ligation for symptomatic hemorrhoids.

Adult↗
PubMed1988

Alterations in key carbohydrate-metabolizing enzyme activities in rat livers following bile duct ligation and its release.

Activities of key carbohydrate-metabolizing enzymes in the livers of rats after bile duct ligation were studied during the recovery phase, after releasing the bile duct from ligation as an external biliary drainage. Enzyme activities were analyzed on the 3rd and 7th days after ligation and on the 3rd and 7th days after releasing the ligation. The altered enzyme activities, which resulted from the ligation of the bile duct, recovered after its release, although the recovery was delayed as when compared with those in the serum liver function tests. Glucokinase was the enzyme which was most delayed in recovery. The decreased activity of glucokinase had not returned to normal, even on the 7th day after release of the bile duct from its 7 day-ligation, whereas all the other enzyme activities had returned to normal by this time. It was also suggested that the decreased activity of glucokinase, which regulates the glucose uptake by the liver, was related to the glucose intolerance in obstructive jaundice. Accordingly, glucokinase can be used as a marker for determining the time of operation after biliary drainage.

Animals↗
PubMed1983

A randomized comparison of single and multiple rubber band ligations.

One hundred consecutive office patients with internal hemorrhoidal disease were treated by rubber band ligations. They were assigned randomly to one, two, or three ligations at one session. No statistically significant differences in morbidity or complications resulted from multiple ligations, as compared with one ligation. No serious complications were encountered in any of the treatment groups. These results confirm that multiple rubber band ligation is as safe and effective a procedure for managing internal hemorrhoidal disease as single ligations.

Adult↗
PubMed1996

Effects of pancreatic duct ligation and aging on acute taurocholate-induced pancreatitis. Experiments in the perfused pancreas in rats.

CONCLUSION: When taurocholate was injected into the common bile duct, high ductal pressure due to ligation of the pancreatic duct did not produce more damage in the pancreas of both old rats and young adult rats, and levels of pancreatic enzymes in portal venous effluent were lower in old rats than in younger rats. BACKGROUND: The effects of ligation of the pancreatic duct and aging on acute pancreatitis caused by taurocholate are still unclear. METHODS: Young adult and old male Wistar rats were used. Six hours after ligation of the common bile duct in both the duodenum and liver hilus, rats were killed and the pancreata were perfused. Taurocholate or normal saline was injected retrogradely into the common bile duct. The levels of amylase and lipase in the portal venous effluent were determined as markers of damage to the pancreas. The pancreas was also histologically examined after the perfusion experiments using an Image Analysis System. RESULTS: (1) A nonsignificant elevation of pancreatic enzymes was found in portal venous effluent by the retrograde injection of saline into the common bile duct. Injection of taurocholate caused a marked elevation of enzymes in the effluent for the first 30 min after injection, which then gradually decreased. (2) Basal levels of pancreatic enzymes were significantly higher in the ligation group than in the nonligation group. Injection of saline into the common bile duct had no apparent effect on enzymes in the effluent. In contrast, taurocholate injection into the common bile duct produced a marked increase in enzymes in the portal venous effluent. However, no significant difference was found between the ligation group and the nonligation group. (3) Similar findings were obtained when old rats were used. (4) Although basal levels of enzymes were almost the same in nonligated old and young adults rats, taurocholate injection into the pancreatic duct in old rats resulted in a significant depression of enzymes compared to that in young adult rats. In the ligation group, pancreatic enzymes in the portal venous effluent following taurocholate injection tended to be lower in old rats than in young adult rats. The results were histologically supported in that various degrees of fibrosis were found in the pancreata of old rats.

Acute Disease↗
PubMed1991

Altered anomeric specificity of glucose-induced insulin release in rabbits with duct-ligated pancreas.

Ligation of the pancreatic duct in rabbits provokes a decrease in the insulin and glucagon content of the pancreas, and may lead to chronic hyperglycemia. The insulin secretory behavior of the perfused pancreas is perturbed in duct-ligated animals, and this is illustrated in several respects: 1. The steady-state insulin output evoked by L-leucine (10 mM) is higher in duct-ligated than control rabbits; 2. In the presence of the amino acid, the response to D-glucose is characterized by a delayed onset, the absence of an early secretory peak, and a sluggish return towards basal value upon removal of the hexose from the perfusate; and 3. Whereas control rabbits display a higher secretory response to alpha- than beta-D-glucose, such is no more the case in duct-ligated rabbits. The perturbation of the anomeric specificity in secretory response is most obvious in diabetic duct-ligated rabbits, in which case beta-D-glucose stimulates insulin release more efficiently than alpha-D-glucose. In both control and duct-ligated rabbits, however, the alpha-anomer is more potent than the beta-anomer in suppressing leucine-stimulated glucagon secretion. These findings are compatible with the view that chronic hyperglycemia leads to alteration in the anomeric preference of the pancreatic B-cell for alpha-D-glucose, possibly as a result of the nonenzymatic glycation of glycolytic enzymes in insulin-producing, but not glucagon-producing, islet cells.

Animals↗