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PubMed2002

Lessons learned from ligation of indirect hernia sac: an alternative to reduction during endoscopic extraperitoneal inguinal hernioplasty.

BACKGROUND: During endoscopic totally extraperitoneal inguinal hernioplasty (TEP), complete reduction of the hernia sac is not always feasible because a sac extends into the scrotum or is adhesed. In such circumstances, ligation of the hernia sac appears to be a sound alternative to reduction. The present study was undertaken to evaluate the safety of sac ligation and the clinical results for patients who underwent ligation of an indirect hernia sac during TEP. PATIENTS AND METHODS: From September 1999 to July 2001, patients undergoing unilateral TEP for indirect inguinal hernia were recruited. Patients were divided into two groups. Group 1 (n = 65) underwent complete reduction of the hernia sac, whereas group II (n = 34) underwent ligation of the sac with a Vicryl suture followed by distal transection. Clinical parameters and outcome data were compared between the two groups of patients. RESULTS: Demographic features and hernia types between the two groups were comparable. The mean operative times of patients from groups I and II were 58 and 62 minutes, respectively (P = NS). Intraoperative complications occurred in two patients in group II, including a vas deferens transection and a gonadal vessel division. Comparison of the lengths of hospital stay, postoperative pain scores at rest and on coughing, rates of postoperative morbidity, and incidences of groin collection showed no significant differences between the two groups. CONCLUSIONS: Our findings highlight the importance of clear identification and protection of the vas deferens and gonadal vessels before transection of the ligated sac, particularly in patients with abundant preperitoneal adipose tissue. Ligation of an indirect hernia sac was associated with a higher incidence of intraoperative complications and should be performed with caution during TEP.

Case-Control Studies↗
PubMed1988

Simultaneous endocardial and epicardial monophasic action potential recordings during brief periods of coronary artery ligation in the dog: influence of adrenaline, beta blockade and alpha blockade.

Local differences in the time course of recovery of excitability during the early phase of myocardial ischaemia are important in the genesis of arrhythmias. Catecholamines are known to encourage the formation of arrhythmias and adrenergic blockade is a recognised therapeutic regime. The purpose of this study was to compare the effect of short periods of coronary artery ligation on endocardial and epicardial repolarisation time, to assess any disparity between the two surfaces, and investigate the influence of catecholamines and adrenergic blockade. Simultaneous left ventricular endocardial and epicardial monophasic action potentials (MAPs) were recorded during short periods of left anterior descending coronary artery (LAD) ligation in 9 open chested dogs. Recordings were made during two 90 s periods of LAD ligation. Two further ligations were made during infusion of adrenaline (1 microgram.kg-1.min-1). Subsequently ligations were made after beta blockade with propranolol (0.25 mg.kg-1) and then in the presence of a combination of alpha blockade (phentolamine, 0.15 mg.kg-1) and beta blockade. MAP duration was measured at 90% repolarisation. LAD ligation produced a marked shortening of MAP duration epicardially with only minimal shortening endocardially, which resulted in a highly significant difference between the repolarisation times on the two surfaces. The disparity between surfaces tended to be augmented by adrenaline and was significantly minimised by either beta blockade alone or in combination with alpha blockade. Our results show rapid development of substantial regional differences in repolarisation time between endocardium and epicardium in response to "ischaemia".(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed2003

Fertility and pregnancy outcomes following hypogastric artery ligation for severe post-partum haemorrhage.

BACKGROUND: Hypogastric artery ligation is a therapeutic option for severe post-partum haemorrhage. Little is known about the outcomes of subsequent fertility and pregnancy. We studied these parameters in women who required hypogastric artery ligation for severe post-partum haemorrhage in our institution over a 13-year period. METHODS: All patients who required hypogastric artery ligation for severe intractable post-partum haemorrhage from January, 1989 to April, 2001 were included. Data were retrieved from medical files and telephone interviews. RESULTS: A total of 68 patients required hypogastric artery ligation during the study period. Seventeen patients had 21 pregnancies with 13 term deliveries, two ectopic pregnancies, three miscarriages, and three abortions. Twenty-eight patients did not want a new pregnancy and one patient refused the interview. Twenty-three (34%) patients were lost to follow up. None of the patients suffered subsequent infertility and pregnancy was achieved in <12 months once planned. Pregnancy outcomes were normal. Fifty-four percent had vaginal deliveries. Three patients suffered a threatened post-partum haemorrhage that was easily treated medically. CONCLUSIONS: This is the largest reported series of pregnancies following hypogastric artery ligation. Hypogastric artery ligation for post-partum bleeding >1 l appears to be a safe procedure that does not impair subsequent fertility and pregnancy outcomes.

Adult↗
PubMed1994

Impaired cerebral autoregulation in the newborn lamb during recovery from severe, prolonged hypoxia, combined with carotid artery and jugular vein ligation.

OBJECTIVE: To study the effect of severe prolonged hypoxia combined with ligation of the carotid artery and jugular vein (simulating pre-extracorporeal membrane oxygenation [ECMO] events) on cerebral autoregulation in the newborn lamb. DESIGN: Animal studies, using the newborn lamb, with comparison of two randomized treatment groups. SUBJECTS: Newborn lambs of mixed breed, 1 to 7 days of age, were used for the study. Two groups of animals were studied: a normoxic control group (n = 7) and a hypoxic group (n = 8). SETTING: Work was conducted in the research laboratories of the Department of Anesthesiology, Critical Care Medicine at The Johns Hopkins Medical Institutions, Baltimore, MD. INTERVENTIONS: Animals were anesthetized (pentobarbital), intubated, and mechanically ventilated. We examined the effect of prolonged severe hypoxia combined with carotid artery and jugular vein ligation on cerebral autoregulation during recovery from this insult. Control animals were maintained in a normoxic state (3 hrs) without carotid artery or jugular vein ligation. Hypoxic animals with carotid artery and jugular vein ligation were exposed to a 2-hr period of hypoxia (arterial oxygen saturation 44 +/- 14%; PaO2 30 +/- 3 torr [4 +/- 0.4 kPa]) followed by a 1-hr normoxic recovery period. Cerebral autoregulation was evaluated at the end of the 1-hr recovery period in hypoxic animals, and after 3 hrs of normoxia in control animals. Cerebral perfusion pressure was decreased by increasing intracranial pressure, with infusion of artificial cerebrospinal fluid into an intracranial pressure catheter in the lateral ventricle of the brain. MEASUREMENTS: Studies were taken at four ranges of cerebral perfusion pressure: > 55 mm Hg; 55 to 40 mm Hg; 39 to 26 mm Hg; and < or = 25 mm Hg. Cerebral blood flow was measured using the radiolabeled microsphere technique. Cerebral oxygen consumption, fractional oxygen extraction, and oxygen transport values were calculated at each study period. MAIN RESULTS: Two hours of severe hypoxia increased cerebral blood flow by 110%, whereas cerebral oxygen consumption was unchanged. In hypoxic animals, cerebral autoregulation was altered, with both cerebral blood flow and cerebral oxygen consumption decreasing at a cerebral perfusion pressure of 39 to 26 mm Hg compared with unchanged cerebral blood flow or cerebral oxygen consumption at a cerebral perfusion pressure of < or = 25 mm Hg in control animals. At the point of loss of autoregulation, significant right-to-left hemispheric cerebral blood flow changes occurred in hypoxic animals. In hypoxic animals, cerebellar cerebral blood flow changes were similar to those changes in the total cerebrum, while brain stem and caudate decreased cerebral blood flow only at a cerebral perfusion pressure of < or = 25 mm Hg. CONCLUSIONS: These findings indicate that cerebral autoregulation is disrupted during the recovery phase from an insult caused by prolonged, severe hypoxia with carotid artery and jugular vein ligation. This insult results in significant differences in right and left hemispheric cerebral blood flow rates when cerebral autoregulation is lost. If these results can be extrapolated to the human state, they may help to explain the role of pre-ECMO hypoxia combined with vessel ligation as a risk factor in cerebral injury in ECMO patients.

Animals↗
PubMed1996

Comparative effects of idazoxan, prazosin, and yohimbine on coronary ligation-induced arrhythmias in spontaneously hypertensive rats.

We investigated whether certain drugs with alpha-adrenergic antagonist activity display anti-arrhythmic effects in hypertensive animals subjected to acute coronary artery ligation. The left anterior descending coronary artery (LAD) was ligated in open-chest pentobarbital-anesthetized spontaneously hypertensive rats (SHR); arrhythmias were subsequently recorded for 30 min. Drugs were administered intravenously, (i.v.) 5 min before ligation. The effects of yohimbine and idazoxan were compared with those of prazosin. Prazosin (100 mu g/kg) increased the occurrence of ventricular tachycardia (VT). In contrast, yohimbine 1.6 mg/kg decreased both the occurrence and the duration of VT and the occurrence and the duration of ventricular fibrillation, (VF). The results obtained with idazoxan 1 mg/kg were similar to those with yohimbine. The ECG alterations induced by coronary artery ligation in rats treated with yohimbine and idazoxan were more pronounced than in controls and in rats treated with prazosin, suggesting that the antiarrhythmic effects observed were not mediated by antiischemic activity. The protective effects against ligation-induced arrhythmias were preceded by a hypotensive effect and a decrease in the rate-pressure product in yohimbine-treated but not in idazoxan-treated animals. In rats treated with prazosin, more arrhythmic events were observed, although hemodynamics were similar to those in rats treated with yohimbine. Our results suggest that the yohimbine-induced antiarrhythmic action is not due to an alteration of conduction or repolarization rates. In this model, yohimbine and idazoxan appear to protect against ligation-induced arrhythmias. These data suggest that drugs with alpha-adrenergic properties might influence the nervous drive to the heart in SHR with cardiac ischemia. However, further investigations are needed to ascertain whether the alpha-adrenoceptor blockade participates in this effect.

Adrenergic alpha-Antagonists↗
PubMed1995

Laparoscopic simultaneous ligation of internal and external spermatic veins for varicocele.

The conventional treatment of varicocele consists of interruption of reflux in the internal spermatic vein either by open retroperitoneal high ligation, an open inguinal approach or percutaneous embolization. Recently, high ligation of the internal spermatic vein has been performed via laparoscopy. We previously suggested that ligation of the internal spermatic vein alone is not adequate, and a comparative study has shown that our method of trans-inguinal ligation of the internal and external spermatic (cremasteric) veins yields better surgical results. A laparoscopic version of this operation is described, which was performed in 25 patients for 31 ligations (6 bilateral cases). Short-term results (followup at 3 months) have shown that the procedure is safe and effective (no complications, 24-hour hospitalization and 1 case of persistence due to a technical error). This procedure seems to be an attractive alternative to our trans-inguinal combined approach especially if bilateral ligation is necessary.

Adolescent↗
PubMed2005

Distinct mouse coronary anatomy and myocardial infarction consequent to ligation.

UNLABELLED: This study describes the coronary anatomy of C57BL/6 mice and the functional impact of that anatomy on myocardial infarctions induced by ligation of the left coronary artery. In contrast to humans, a distinct septal coronary artery was observed in all mice arising either from a separate ostium from the right sinus of Valsalva or as a branch of the right coronary artery. Ligation of the left coronary artery at the site of its emergence from under the left atrium resulted in reproducible large myocardial infarctions involving the anterolateral, posterior, and apical regions of the heart as evidenced by histology and echocardiography. Interestingly, the septum was spared from infarction as predicted by the presence of the distinct septal branch found in mice. Thus, the distinct mouse coronary artery anatomy results in different regionality of infarction compared with man and large laboratory animals, and this may affect on the associated pathological remodeling of the heart. BACKGROUND: The objective of this study was to describe the coronary anatomy of C57BL/6 mice and determine the functional impact of that anatomy on myocardial infarctions induced by ligation of the left coronary artery. METHODS: C57BL/6 mice were used to visualize mouse coronary anatomy and to generate myocardial infarction. Mouse coronary artery visualization was performed on isolated hearts using injection of Silastic sealant into the aortic arch. After left thoracotomy myocardial infarction was produced by ligating the left coronary artery at the site of the vessels' emergence past the tip of the left atrium. Echocardiography was performed to analyze heart function, and histology was performed to delineate myocardial infarction. RESULTS: The different septal coronary artery was observed in all mice arising either from a separate ostium from the right sinus of Valsalva or as a branch of the right coronary artery. The mouse left coronary artery passed obliquely across the left ventricular free wall similar to the ramus intermedius coronary artery variant in man. Ligation of the left coronary artery as it emerged from under the left atrium resulted in reproducible large infarctions involving the anterolateral, posterior, and apical regions of the heart as demonstrated by histology and echocardiography. Notably, the septum was spared from infarction as predicted by the presence of the distinct septal coronary artery found in mice. CONCLUSIONS: Mouse coronary anatomy is distinct compared to man or large laboratory animals, and myocardial infarctions resulting from ligation of the mouse left coronary artery spare the septum, which may affect the pathological remodeling of the heart.

Animals↗
PubMed2005

Endoscopic variceal ligation vs. propranolol for prevention of first variceal bleeding: a randomized controlled trial.

OBJECTIVES: Data in the literature regarding the role of endoscopic variceal ligation for the prevention of first variceal bleeding in cirrhotic patients are controversial. To further explore this issue we have compared ligation and propranolol treatment in a prospective randomized study. METHODS: Sixty patients with cirrhosis and oesophageal varices with no history but at high risk of bleeding were randomized to ligation treatment (30 patients) or propranolol (30 patients). Patients were followed for approximately 27.5 months. RESULTS: Variceal obliteration was achieved in 28 patients (93.3%) after 3+/-1 sessions. The mean daily dose of propranolol was 60.3+/-13.3 mg. Two patients (6.7%) in the ligation group and nine patients (30%) in the propranolol group developed variceal bleeding (P = 0.043). The actuarial risks of variceal bleeding at 2 years were 6.7% and 25%, respectively. On multivariate analysis, propranolol treatment and grade III varices turned out to be predictive factors for the risk of variceal bleeding. Mortality was not different between the two groups. There were no serious complications due to ligation. Propranolol treatment was discontinued in four patients because of side effects. CONCLUSIONS: Variceal ligation is a safe and more effective method than propranolol treatment for the prevention of first variceal bleeding in cirrhotic patients with high-risk varices.

Adrenergic beta-Antagonists↗
PubMed2006

How many ligations of bilateral segmental arteries cause ischemic spinal cord dysfunction? An experimental study using a dog model.

STUDY DESIGN: Segmental arteries were interrupted bilaterally for up to 7 levels to study the effects on spinal cord blood flow and neurologic function in dogs. OBJECTIVE: To examine how many ligations of bilateral segmental arteries cause ischemic spinal cord dysfunction. SUMMARY OF BACKGROUND DATA: Interruption of bilateral segmental arteries for up to 3 levels has been reported not to damage spinal cord function. However, to our knowledge, the effects of ligating more than 3 levels have not yet been clearly determined. METHODS: There were 15 dogs divided into 5 groups: sham group, no ligation; group 1, ligation of bilateral segmental arteries at 3 levels (T11-T13); group 2, at 4 levels (T10-T13); group 3, at 5 levels (T10-L1); and group 4, at 7 levels (T9-L2). Spinal cord blood flow at T12 measured by laser Doppler flowmetry, and spinal cord-evoked and motor-evoked potentials were measured simultaneously until 10 hours after ligation. Neurologic function was assessed using a modified Tarlov grading system 1 week after operation in 20 other dogs divided into 4 groups (1, 2, 3, and 4). RESULTS: Spinal cord blood flow was 99.3%, 80.7%, 71.5%, 44.3%, and 25.0% in the sham group, and groups 1, 2, 3, and 4, respectively, 10 hours after ligation. Abnormal spinal cord-evoked potentials were observed in 2 of 3 dogs in group 3 and all 3 in group 4. Abnormal motor-evoked potentials were observed in 1 of 3 dogs in group 3 and all 3 in group 4. Postoperative neurologic evaluation identified all 5 dogs in groups 1 and 2, respectively, and 3 in group 3 as having grade 5. There were 2 dogs in group 3 and 3 in group 4 that had grade 4, and 2 in group 4 had grade 3. CONCLUSION: Interruption of bilateral segmental arteries at > or =5 consecutive levels risks producing a spinal cord ischemia capable of injuring the spinal cord.

Animals↗
PubMedDate not supplied

Comparison of artery-ligating and artery-preserving varicocelectomy: effect on post-operative spermatogenesis.

To evaluate the effects of ligature of the internal spermatic artery at varicocelectomy on fertility, we conducted a prospective randomized study for comparison of two surgical methods (artery-ligated and artery-preserved). A total of 66 infertile patients with palpable varicocele was randomly assigned to an artery-ligated or artery-preserved group at varicocelectomy and the change in seminal characteristics and testis volume was prospectively investigated. Sperm density and motility improved significantly in the artery-ligated group. There was significant improvement in sperm density in the artery-preserved group, but motility did not reach the level of statistical significance in this group. The significant change in testis volume was not observed in both groups. Seven (23.3%) of 30 patients in the artery-ligated group and 5 (13.9%) of 36 men in the artery-preserved group managed to impregnate their partners. The difference was not statistically significant. In spite of the advocative advantage of artery preservation, our present study did not show any significant difference between artery-ligating and artery-preserving varicocelectomy when improvements in semen quality and pregnancy rate were assessed. Thus, artery-ligated varicocelectomy is warranted with regard to post-operative fertility in the patients with clinical varicocele.

Adult↗
PubMed2004

Experimental bile-duct ligation resulted in accumulation of oxidized low-density lipoproteins in BALB/c mice liver.

BACKGROUND AND AIM: Oxidized low-density lipoproteins (LDL), which are produced during oxidative stress by the process of lipid peroxidation, have also been proposed to have complex roles in many other immuno-inflammatory mechanisms. It has been shown that bile-duct ligation results in oxidative stress in the liver of animals. The aim of this study was to investigate if oxidized LDL are produced in the liver tissues of bile-duct-ligated mice. METHODS: Obstructive jaundice was induced in BALB/c mice by the ligation and division of the common bile duct. Liver concentrations of glutathione and malondialdehyde were measured in the sham-operated (n = 10) and bile-duct-ligated (n = 10) mice on the 10th day of obstructive jaundice. The presence of oxidized LDL in the liver tissue sections was evaluated using a special, novel immunofluorescent staining method. The final step was to explore the existence of oxidized LDL under fluorescent microscopy. RESULTS: Compared with sham-operated mice, jaundiced mice showed significantly higher levels of malondialdehyde and lower concentrations of reduced glutathione in the liver. While there was no staining in the sham-operated group, bile-duct ligation resulted in positive oxidized LDL staining in the liver tissues of mice. The present study testifies that bile-duct ligation results in oxidative stress and enhanced lipid peroxidation in the hepatic tissues of BALB/c mice and moreover, that oxidized LDL accumulate in the liver of mice with experimental obstructive jaundice. CONCLUSION: Oxidized LDL may be an important and direct indicator of ongoing oxidative stress and enhanced lipid peroxidation in obstructive jaundice. The potential roles of this finding were also discussed, briefly.

Animals↗
PubMed2005

Endothelial nitric oxide synthase is not essential for the development of fibrosis and portal hypertension in bile duct ligated mice.

BACKGROUND/AIMS: It is postulated that nitric oxide (NO) is responsible for the hyperdynamic circulation of portal hypertension. Therefore, we investigated induction of fibrosis and hyperdynamic circulation in endothelial NO synthase knock-out (KO) mice. METHODS: Fibrosis was induced by bile duct ligation. Hemodynamic studies were performed after portal vein ligation. All studies were performed in wild-type (WT) and KO mice. RESULTS: Three to 4 weeks after bile duct ligation (BDL), both WT and KO groups had similar degrees of portal hypertension, 12 (9-14) and 11(8-15) mmHg, median (range), and liver function. Fibrosis increased from 0.0% in sham operated to 1.0 and 1.1% in WT and KO mice, respectively. Cardiac output was similar after portal vein ligation (20 and 17 ml/min in WT and KO mice, respectively). There was no difference in liver of mRNA for endothelin 1, inducible NO synthase (iNOS) and hem-oxygenase 1 (HO1); proteins of iNOS, HO1 and HO2; nor in endothelin A and B (EtA and EtB) receptor density between WT and KO mice after BDL. CONCLUSIONS: These results suggest that endothelial NO synthase is neither essential for the development of fibrosis and portal hypertension in bile duct ligated mice, nor for the hyperdynamic circulation associated with portal hypertension in the portal vein ligated mice.

Animals↗
PubMed1998

Combined high ligation and stab avulsion for varicose veins in an outpatient setting.

BACKGROUND: In recent years, the transition from radical surgery for the treatment of primary varicose veins has been modified from the previously described high ligation with complete stripping of the greater or lesser saphenous vein. OBJECTIVE: The purpose of the herewith-described technique is to present a less invasive technique that incorporates saphenofemoral ligation with hook avulsion of branch varicosities. METHODS: Sapheno-femoral ligation with hook avulsion of branch varicosities is carried out under local anesthesia utilizing the tumescent technique with dissection, ligation, and division of the greater saphenous vein and its tributaries. The hook avulsion procedure removes residual diseased venous segments. RESULTS: Patients treated by this combined ligation-hook avulsion approach achieve excellent functional and clinical results associated with a minimal side effect profile. CONCLUSIONS: Combined flush sapheno-femoral ligation of normal saphenous veins (< 8 mm in diameter) and hook avulsion of branch tributaries produces excellent functional and cosmetic results with minimal morbidity.

Ambulatory Surgical Procedures↗
PubMed2000

Bacterial peritonitis after elective endoscopic variceal ligation: a prospective study.

OBJECTIVE: Endoscopic variceal ligation is becoming the therapy of choice for esophageal varices, replacing endoscopic variceal sclerotherapy. The latter is associated with a 5-53% incidence of port-procedural bacteremia and a 0.5-3% incidence of peritonitis, whereas the former carries a 3-6% risk of bacteremia. However, the incidence of peritonitis after variceal ligation has not been well studied. This prospective study is designed to investigate the risk of developing bacteremia and bacterial peritonitis after elective endoscopic variceal ligation. METHODS: Sixty-seven patients with esophageal varices and ascites secondary to liver cirrhosis underwent elective endoscopic variceal ligation. Before the procedure, ascitic fluid was drawn under ultrasound guidance and sent for cell counts, Gram stain, and cultures. Two to 4 days afterward, a repeat ascitic fluid sample was sent for the same studies whether or not the patient had symptoms or signs suggestive of infection. Blood cultures were drawn both immediately before and after the endoscopic ligation procedure. RESULTS: Of 67 subjects, 11 developed asymptomatic bacteremia with Gram-positive commensals. However, none of them progressed to peritonitis. Two patients who did not have bacteremia developed mild febrile peritonitis with Escherichia coli and were successfully treated with oral antibiotics. No other infectious complications were noted. CONCLUSIONS: There is a significant risk of asymptomatic bacteremia and bacterial peritonitis after elective variceal ligation. The peritonitis does not seem to be related to the bacteremia, as patients who had bacteremia did not develop peritonitis and vice versa. In addition, the involved organisms were quite different. Unlike the bacteremia, postligation peritonitis may be a consequence of severe liver cirrhosis rather than the procedure itself. The clinical significance of postligation bacteremia is doubtful. With regard to peritonitis, in our opinion the use of prophylactic antibiotics should be reserved for patients with Child's C class cirrhosis, a recent history of variceal bleeding, a past history of bacterial peritonitis, or a comorbid immunosuppressive condition.

Adult↗
PubMed1972

Compensatory hypertrophy of the contralateral kidney after unilateral ureteral ligation.

1. The ligation of one ureter is accompanied by compensatory hypertrophy of the contralateral kidney.2. The rate of growth of the contralateral kidney after ligation of the opposite ureter is similar to that observed after unilateral nephrectomy.3. Ligation of one ureter produced ipsilateral hydronephrosis.4. The development of hydronephrosis was accompanied by a marked increase of DNA, suggesting hyperplasia, and of the rate of anaerobic glycolysis, while the rate of oxygen uptake decreased, especially in the cortex.5. During compensatory hypertrophy of the contralateral kidney, after ligation of the opposite ureter, there were increases of RNA/DNA ratios and of oxygen uptake, especially marked in the cortex, and in every respect similar to those observed after unilateral nephrectomy.6. Ligation of one ureter resulted in an increase of glomerular filtration rate of the contralateral kidney similar to that observed after unilateral nephrectomy.7. The mechanisms of contralateral renal hypertrophy after ligation of one ureter and after unilateral nephrectomy are discussed. It is suggested that in both cases the prime mover to compensatory hypertrophy is the increase of glomerular filtration rate.

Animals↗
PubMed1983

Renin dependence of captopril-induced drinking after ureteric ligation in the rat.

In experiments lasting 8 h, low (0.5 mg kg-1) or medium (5 mg kg-1) subcutaneous doses of the angiotensin-converting enzyme inhibitor captopril were mildly dipsogenic in sham-operated rats, much more so in rats subjected to bilateral ureteric ligation and not at all in bilaterally nephrectomized rats. Rats with ligated ureters drank enough water to gain weight during the experiments. All other groups lost weight. The enhanced responsiveness of rats with ligated ureters, despite fluid retention, shows that captopril-induced drinking was not secondary to increased renal fluid loss. Ureteric ligation alone which caused some increase in renin secretion was mildly dipsogenic compared with sham operation. Captopril caused further increases in plasma renin concentration and more drinking suggesting that the captopril response is renin-dependent. The failure of the nephrectomized rat to drink after captopril also shows that the response is renin-dependent. The highest dose (50 mg kg-1) of captopril did not at first stimulate drinking, though water intake increased later. Slowness to drink was not the result of general depression of behaviour since drinking in response to subcutaneous hypertonic NaCl or intracranial angiotensin II was not inhibited by the highest dose. Slowness to drink after the highest dose was attributable to blockade of converting enzyme centrally as well as peripherally. This meant that the increased circulating angiotensin I resulting from peripheral blockade of converting enzyme was only slowly converted to angiotensin II in the brain. When cerebral conversion of angiotensin I was prevented by a single intracranial injection of 25 micrograms captopril, drinking in response to the lower doses of captopril was also inhibited in normal rats and in rats with ligated ureters. The same intracranial dose of captopril also inhibited drinking in response to intracranial injections of renin or angiotensin I, but not angiotensin II. The time course of inhibition of renin-induced drinking was similar to that of inhibition of subcutaneous captopril-induced drinking. In conclusion, subcutaneous captopril causes increased water intake through activation of the renal renin-angiotensin system, an effect that is enhanced when the system has already been partly activated by ureteric ligation. Increased circulating angiotensin I resulting from blockade of peripheral converting enzyme must be converted to angiotensin II in the brain in order to stimulate drinking. Drinking is not the consequence of increased fluid loss.

Angiotensins↗
PubMed1984

Exchange area and surface properties of the microvasculature of the rabbit submandibular gland following duct ligation.

The exchange area of the submandibular salivary gland microvasculature has been measured to allow the value of microvascular permeability (P) to hydrophilic solutes to be calculated from previous measurements of permeability-surface area (PS) products. Glands whose ducts had been ligated for 2 weeks and the contralateral control glands were perfusion-fixed with a modified Karnovsky's fixative after perfusion with a solution containing cationized ferritin, and examined with transmission electron microscopy. Stereological techniques were used to estimate the surface area of the exchange vessels on random thin sections from four control and four duct-ligated glands. The mean exchange surface area in control glands was 512 cm2 g-1 and 336 cm2 g-1 in duct-ligated glands. The fenestral density was calculated to be 0.57% of the exchange surface in control glands and 0.30% in duct-ligated tissue. Molecules of cationized ferritin appeared bound to the luminal surface of the microvascular endothelium, including the surface of the fenestrae to a depth of about 25 nm in both control and ligated glands. These experiments have shown that the exchange surface area of the fenestrated endothelium of the submandibular salivary gland is comparable to that in cardiac muscle but the permeability (P) to small solutes is about 10 times greater. Following ligation of the salivary gland duct, solute permeability falls and an explanation of this, based on the reduced surface area and the nature of the permeability-flow relationship for small solutes is offered.

Animals↗
PubMed1983

Prospective randomised comparison of photocoagulation and rubber band ligation in treatment of haemorrhoids.

Two hundred and sixty eight patients with haemorrhoids were allocated at random to treatment by either photocoagulation (group 1, n=141) or rubber band ligation (group 2, n=127) and followed up for one year. There was no significant difference in the symptomatic outcome of treatment between the two groups at one, four, or 12 months, irrespective of whether first or second degree haemorrhoids were treated. Side effects of treatment (bleeding or severe pain) were significantly more common after rubber band ligation (n=11) than after photocoagulation (n=2; p less than 0.01). Further outpatient treatment, however, was required significantly more often after photocoagulation (n=23) than rubber band ligation (n=6) (p greater than 0.02), and 19 patients (14 in group 1 and five in group 2; NS) subsequently had a haemorrhoidectomy. At one year 26 of 103 patients were dissatisfied after photocoagulation compared with 20 of 88 after rubber band ligation. Photocoagulation is a safe and comfortable treatment which gives long term results that are as good as those of rubber band ligation. Complications are more common after rubber band ligation, but further treatment is required more commonly after photocoagulation.

Adolescent↗