Vagal afferent-dependent cholecystokinin modulation of visceral pain requires central amygdala NMDA-NR2B receptors in rats.

BACKGROUND: Cholecystokinin (CCK), a gut hormone that is released during feeding, exerts gastrointestinal effects in part through vagal pathway. It is reported to be a potential trigger for increased postprandial visceral sensitivity in healthy subjects and, especially in patients with irritable bowel syndrome. NR2B-containing N-methyl-d-aspartate (NMDA) receptors in the central amygdala (CeA) participate in pain modulation. Systemically administered CCK activates the CeA-innervating neurons. Here, we investigated whether CCK modulation of visceral sensitivity is mediated through CeA NMDA-NR2B receptors and whether this modulation involves vagal pathway. METHODS: We first examined the visceromotor response (VMR) to colorectal distention (CRD) following i.p. injection of CCK octapeptide (CCK-8) in a rat model. Next, the NR2B antagonist ifenprodil and the NR2A antagonist NVP-AAM077 were microinjected into the CeA before systemic CCK injection. NR2B phosphorylation was detected by Western blot. To down-regulate NR2B gene expression, NR2B-specific small interfering RNA (siRNA) was delivered into CeA neurons by electroporation. In addition, the effects of functional deafferentation by perivagal application of capsaicin and pretreatment with the CCK1 receptor antagonist devazepide were investigated. KEY RESULTS: CCK-8 increased VMR to CRD in a dose-dependent manner. This effect was blunted by intra-CeA administration of ifenprodil (but not NVP-AAM077) and was accompanied by phosphorylation of NR2B subunits in the CeA. CCK failed to increase VMR to CRD in NR2B siRNA-treated rats. Perivagal capsaicin application and pretreatment with devazepide prevented CCK-induced pronociception and CeA NR2B phosphorylation. CONCLUSIONS & INFERENCES: The pronociception induced by systemic CCK, which is vagal afferent-dependent, requires activation of CeA NMDA-NR2B receptors.

Endoscopic balloon dilatation is a safe method in the management of common bile duct stones.

BACKGROUNDS AND AIMS: Endoscopic sphincterotomy is a widely accepted treatment for patients with common bile duct stones. Despite improvement in this technique, endoscopic sphincterotomy is still associated with some biliary complications. Endoscopic balloon dilatation is a less traumatic and sphincter preserving method for removal of common bile duct stones. However, the results of controlled studies in comparison with these two methods are contradictory. The aim of this study is to compare the safety and efficacy of endoscopic balloon dilatation and endoscopic sphincterotomy in Chinese patients. PATIENTS AND METHODS: A total of 104 patients with common bile duct stones on endoscopic retrograde cholangiopancreatography were enrolled. They were randomly assigned to endoscopic balloon dilatation or endoscopic sphincterotomy. Endoscopic balloon dilatation was performed by using a balloon dilator to dilate the sphincter for 5 min. The common bile duct stones were then removed by a Dormia basket after endoscopic balloon dilatation or endoscopic sphincterotomy. Mechanical lithotripsy was performed if the stones were difficult to remove by Dormia basket. After discharge, patients were regularly followed up for biliary complications. RESULTS: The successful bile duct stone clearance rate was 94.1% in endoscopic balloon dilatation group and 100% in endoscopic sphincterotomy group. Post-procedural significant haemorrhage was higher in endoscopic sphincterotomy group than in endoscopic balloon dilatation group (14/53 versus 1/48, P < 0.001). The bleeding patient from endoscopic balloon dilatation group was a case of uremia and bleeding occurred 48 h after endoscopic balloon dilatation. All the patients with post-procedural haemorrhage were controlled endoscopically. The post-procedural serum amylase level showed no significant difference in both groups and none of them developed clinical pancreatitis. After a mean 16 months follow-up, three patients (6.3%) in endoscopic balloon dilatation group and four patients (7.5%) in endoscopic sphincterotomy group developed recurrent common bile duct stones. The recurrent common bile duct stones were multiple and muddy in consistency. They were successfully removed endoscopically. CONCLUSION: Both endoscopic balloon dilatation and endoscopic sphincterotomy are safe and effective techniques for the treatment of common bile duct stones. Endoscopic balloon dilatation can be safely applied in patients with coagulopathy and does not increase the incidence of pancreatitis or bleeding.

Effect of somatostatin on the sphincter of Oddi in patients with acute non-biliary pancreatitis.

BACKGROUND: Somatostatin has been used to prevent pancreatitis after endoscopic retrograde cholangiopancreatography but its effect on acute non-biliary pancreatitis is still unclear. AIM: The purpose of this study was to evaluate the function of the sphincter of Oddi (SO) and the effect of somatostatin on patients with non-biliary pancreatitis. METHODS: Twenty patients (18 males, two females) with acute pancreatitis (alcoholic 18, idiopathic two) received SO manometry within one week after admission. After baseline measurement, a bolus dose of somatostatin (Stilamin, Serono) 250 microg was infused slowly, and SO manometry was repeated after five minutes. Continuous infusion of somatostatin 250 microg/h was given for 12 hours after SO manometry. Serum amylase, lipase, glucose, and C reactive protein (CRP) levels were examined before and after somatostatin infusion. RESULTS: SO manometry was unsuccessful in six patients due to contracted sphincter. In the remaining 14 patients, high SO basal pressure (SOBP >40 mm Hg) was found in seven patients. After somatostatin infusion, mean SOBP decreased from 48.8 (29) to 31.9 (22) mm Hg (p<0.01). One patient had a paradoxical reaction to somatostatin (SOBP increased from 30 to 50 mm Hg) while the other 13 patients had a fall in SOBP after somatostatin. One patient developed abdominal pain with a serum amylase level of 2516 IU/l after SO manometry. No other side effects or changes in amylase, lipase, glucose, or CRP levels were observed in the other 19 patients after SO manometry and somatostatin infusion. DISCUSSION: Sphincter of Oddi dysfunction is common in patients with acute non-biliary pancreatitis and in most cases somatostatin can relax the sphincter.

The effects of endoscopic variceal ligation and propranolol on portal hypertensive gastropathy: a prospective, controlled trial.

BACKGROUND: Endoscopic treatment of esophageal varices may accentuate portal hypertensive gastropathy. The impact of the combination of band ligation and propranolol on this condition remains unknown. METHODS: Patients with history of variceal bleeding were randomized to receive band ligation alone (control group, 40 patients) or a combination of band ligation and propranolol (propranolol group, 37 patients). Serial endoscopic evaluation of gastropathy was performed. Gastropathy was classified into 3 grades and scored as 0, 1, or 2. RESULTS: Before endoscopic treatment, 17% of the control group and 22% of the propranolol group had gastropathy (p = 0.78). The occurrence of gastropathy after endoscopic treatment was significantly higher in the control group than in the propranolol group (p = 0.002). Serial endoscopic follow-up revealed that the mean gastropathy score was significantly higher in the control group than in the propranolol group (p < 0.05). In patients with gastropathy the gastropathy score reached a peak at 6 months after endoscopic treatment in both the control and propranolol groups (85% vs. 48%, respectively). After variceal obliteration, accentuation of gastropathy was significant in the control group (p < 0.01) but not in the propranolol group. Gastropathy was less likely to develop in patients who developed gastric varices. Esophageal variceal recurrence was not related to the development of gastropathy after variceal obliteration with banding. Only one patient in the control group bled from gastropathy. CONCLUSION: Band ligation of esophageal varices may accentuate gastropathy, which in this study was partly relieved by propranolol.

Sequential changes of gastric hyperplastic polyps following endoscopic ligation.

BACKGROUND: Endoscopic ligation has been extensively applied in the management of esophageal and gastric varices with or without bleeding. The varices are automatically eradicated through the use of ligation. However, whether avascular necrosis will occur in a gastrointestinal polyp when the base is ligated remains unclear. The aims of this pilot study were to investigate the sequential changes of gastric hyperplastic polyps following endoscopic detachable snare ligation and to determine the possibility of induction of avascular necrosis in these lesions following ligation. METHODS: Eleven patients with eighteen gastric hyperplastic polyps were treated with endoscopic detachable-snare ligation. The polyps were observed for 5 minutes and biopsies were then conducted. At 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcome of the strangulated polyps. RESULTS: After being strangulated by the detachable snares, a majority of the polyps immediately congested (94%), and then developed cyanotic change (89%) approximately 4 minutes later. Pathological examination revealed severe venous congestion in the lamina propria of the strangulated polyps. On follow-up endoscopy 2 weeks later, all the snares had dropped off, and avascular necrosis occurred in sixteen polyps (89%). All of the polyps with avascular necrosis were detected to have developed cyanotic changes in initial endoscopy. No complications occurred during or following the ligation procedure. CONCLUSIONS: Most gastric hyperplastic polyps develop avascular necrosis following ligation by detachable snare. Cyanotic change is an important predictor of the outcomes of the lesions following endoscopic ligation. The application of this ligation technique in treatment of bleeding or non-bleeding gastrointestinal polyps deserves further investigation.

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Gamma knife radiosurgery for torsion spasm. Report of two cases.

The authors report on two patients who underwent radiosurgery for torsion spasm and evaluate the efficiency of gamma knife radiosurgery (GKS) as an alternative treatment. The first patient was a 33-year-old woman with severe right-sided lower-limb torsion dystonia. The second patient was a 20-year-old man with right-sided upper-limb torsion dystonia. The target was located at the anterior portion of the ventrolateral nucleus. The maximum doses were 150 Gy and 145 Gy, respectively. Double isocenters with a 4-mm collimator were used. Follow up lasted for 18 months and 8 months, respectively. Both patients had excellent clinical improvement 2 to 3 months after GKS, respectively. The authors believe that GKS may be a safe and efficient treatment for torsion spasm.

Radiosurgery for growth hormone-producing pituitary adenomas.

OBJECT: The authors sought to evaluate the effect of gamma knife radiosurgery (GKS) on growth hormone (GH)-producing pituitary adenoma growth and endocrinological response. METHODS: From 1993 to 1997, 79 patients with GH-producing pituitary adenomas were treated with GKS. Seventy-six patients had acromegaly. Sixty-eight patients were treated with GKS as the primary procedure. The tumor margin was covered with a 50 to 90% isodose and the margin dose was 18 to 35 Gy (mean 31.3 Gy). The dose to the visual pathways was less than 10 Gy except in one case. Sixty-eight patients (86%) were followed for 6 to 52 months. Growth hormone levels declined with improvement in acromegaly in all cases in the first 6 months after GKS. Normalization of the hormone levels was achieved in 23 (40%) of 58 patients who had been followed for 12 months and in 96% of cases for more than 24 months (43 of 45), or more than 36 months (25 of 26), respectively. With the reduction of GH hormone levels, 12 of 21 patients with hyperglycemia regained a normal blood glucose level (p < 0.001). The tumor shrank in 30 (52%) of 58 patients who had been followed for 12 months (p < 0.01), 39 (87%) of 45 patients for more than 2 years (p = 0.02), and 24 (92%) of 26 patients for more than 36 months. In the remainder of patients tumor growth ceased. CONCLUSIONS: Gamma knife radiosurgery for GH-producing adenomas showed promising results both in hormonal control and tumor shrinkage. A margin dose of more than 30 Gy would seem to be effective in improving the clinical status, reducing high blood glucose levels, and normalizing hypertension.

Gamma knife radiosurgery for cavernous hemangiomas.

OBJECT: The authors analyzed the outcome of 53 patients with cavernous hemangiomas who underwent gamma knife radiosurgery (GKS) and evaluated the benefit of the treatment. METHODS: From 1994 to 1995, 57 patients were treated with GKS for cavernous hemangiomas. The mean margin dose to the lesions was 20.3 Gy (range 14.5-25.2 Gy) and the prescription isodose was 50 to 80%. The mean follow-up period was 4.2 years. Four patients were lost to follow up. In 18 of 28 patients whose chief complaint was seizures, there was a decrease in seizure frequency. Five of 23 patients with hemorrhage suffered rebleeding 4 to 39 months after GKS. Seventeen patients in whom the hemangiomas were located at the frontal or parietal lobe had neurological disability and in five this was severe. Two patients underwent resection of their hemangioma after GKS. Three experienced visual problems. Follow-up imaging demonstrated shrinkage of the lesion in 19 patients. CONCLUSIONS: A higher margin dose (> 16 Gy) may be associated with a reduction in the incidence of rebleeding after GKS. Higher dosage and severe brain edema after GKS may decrease the frequency and intensity of seizures at least temporarily. Gamma knife radiosurgery may play a role in protection against hemorrhage and in reduction of the rate of seizure in selected cases with the appropriate dose.

Long-term effect of large biliary endoprostheses in high-risk surgical patients with irretrievable common bile duct stones.

BACKGROUND: Endoscopic sphincterotomy and basket extraction are currently used to remove bile duct stones, with a duct clearance rate of 85% to 90%. A biliary endoprosthesis (stent) is an alternative method to treat difficult cases, especially high-risk surgical patients. The aim of this study was to investigate the long-term effect of biliary endoprostheses in patients with irretrievable common bile duct stones. METHODS: From December, 1990, to November, 1998, 546 patients were referred to the Veterans General Hospital-Kaohsiung for endoscopic removal of common bile duct stones. Of them, 12 received long-term biliary endoprosthesis because endoscopic removal or surgery was not suitable. Large-caliber stents (> 10 French) were inserted into 12 patients (5 women and 7 men, mean age, 78.4 years) and they were followed up with regular clinical visits. Quantitative cholescintigraphy was performed in four patients to evaluate biliary emptying after liver function returned to normal. RESULTS: No early complications from stent insertion occurred and a satisfactory resolution of jaundice, pain and fever were noted in all patients. One patient had repeated cholangitis due to stent occlusion and five died from unrelated causes. The median effective period of stent placement was 11 months (range, 1-38 months). Quantitative cholescintigraphy revealed delayed biliary drainage in four patients despite an absence of symptoms after their liver function returned to normal. CONCLUSIONS: Large-caliber stents are a safe and effective treatment for long-term palliation in high-risk patients with retained common bile duct stones.

Influence of endoscopic variceal ligation on oesophageal motility.

BACKGROUND: To determine the change of oesophageal manometry in patients with oesophageal varices before and after oesophageal variceal ligation (EVL). METHODS: Forty-five patients who had liver cirrhosis and oesophageal varices with high risk of bleeding were managed by EVL. Oesophageal manometry was performed just prior to the ligation and 4-6 weeks after obliteration of varices. Another 45 age- and sex-matched patients without hepatic, oesophageal or systemic disease served as the control group. RESULTS: At 5 cm above the lower oesophageal sphincter (LES), the amplitude of the contractive wave was significantly lower in patients before EVL (56.9 +/- 31.8 vs 80.1 +/- 30.1, P< 1.05) and returned to the level of control subjects after EVL (76.5 +/- 37.0 vs 80.1 +/- 30.1, P> 0.05). At 10 cm above LES, the amplitude of the contractive wave was significantly lower in patients before and after EVL than the control group (54.3 +/- 29.2 vs 68.1 +/- 29.5, 54.2 +/- 26.0 vs 68.1 +/- 29.5, respectively, P< 0.05). The percentage of tertiary waves was significantly higher in patients before and after EVL than in the control group (31.4 +/- 36.6 vs 5.8 +/- 15.1, 26.9 +/- 32.9 vs 5.8 +/- 15.1, respectively, P< 0.05). However, no significant swallowing disturbance was noted in patients after EVL. There was significantly greater LES length in patients before EVL (4.0 +/- 0.9 vs 3.4 +/- 0.7, P<0.05) but there was no significant difference in the LES length after EVL as compared with the control group. Eighty-six per cent (39/45) of patients developed paraoesophageal varices and 31% (14/45) developed new varices 6 months after variceal obliteration. However, there was no significant difference in manometry at the time of variceal obliteration between patients with variceal recurrence and those without. CONCLUSIONS: The presence of varices affected oesophageal motility. However, such abnormality had little clinical significance. Endoscopic variceal ligation normalized oesophageal motility and may not induce abnormal oesophageal motility. The manometric change can not be used to predict the recurrence of varices in cirrhotic patients after variceal obliteration.

Gamma knife radiosurgery for hemangioblastomas.

Thirteen patients (11 males, 2 females) with cerebral hemangioblastomas (HABs) were treated with Gamma Knife radiosurgery (GKR). Four patients had multiple lesions in the brain. The remainder had a single lesion. The total number of lesions was 20. Eight cases had recurrent or residual HABs after surgery. In one case diagnosis was confirmed following surgical resection 22 months after GKR. One case was diagnosed by computed tomography (CT), magnetic resonance imaging (MRI) and digital subtraction angiography (DSA). Three patients had von Hippel Lindau (VHL) disease. The mean tumor diameter was 20 mm (range 7.5 to .55 mm). The mean margin dose was 18 Gy (range 12 to 24 Gy). In 5 cases, there was an improvement of symptoms and reduction in tumor volume. In 4 cases the tumor volume and clinical status remained unchanged. In 3 patients, there was clinical deterioration. The cause of this was an increase in tumor cyst volume in 2 cases. Subsequent surgery resulted in clinical improvement. In a third patient with multiple lesions, deterioration was the result of adverse radiation effects in the medulla oblongata. Three patients were subjected to post GKR-surgery with subsequent histopathology. In one, this was due to cyst expansion. In one, it was at the patient's insistence in the presence of a stable clinical and radiological picture. In a third patient with a temporal lobe tumor, it was because of late-developing epileptic seizures. The histopathological findings in these patients showed varying degrees of small vessel thickening and occlusion together with loss of tumor cells. The observations varied in degree according to the time between GKR and the secondary operation. These findings indicate the effectiveness of the treatment. The reduction in vascularity suggests that GKR could make subsequent surgery less hazardous. The observations of this study suggest that while GKR is not adequately reliable for the control of HAB cysts, it can be an effective treatment for solid tumors, especially those in eloquent regions.

Gallbladder function and recurrent stones of the biliary tract in patients after endoscopic sphincterotomy.

BACKGROUND: Change in gallbladder function may occur in patients with an intact gallbladder after endoscopic sphincterotomy (EST). This study was designed to evaluate the factors influencing gallbladder filling after EST and the correlation between gallbladder function and stone recurrence. METHODS: Sixty Chinese patients with symptomatic choledocholithiasis and an intact gallbladder received EST to clear the bile ducts. They were further investigated with sphincter of Oddi manometry (SOM), quantitative cholescintigraphy (QC), and long-term clinical follow-up. RESULTS: Fifty-six of the 60 patients in the study group were confirmed to have a loss of sphincteric function by SOM. QC showed normal gallbladder filling in 35 of these patients and delayed or non-filling in 21 patients. A significantly higher incidence of normal gallbladder filling occurred in patients with juxtapapillary diverticulum than in those without (P < 0.02), but preexisting cholecystolithiasis had no effect on it. During the follow-up period (median, 32 months: range, 9-54 months) 10 of 56 patients developed recurrent choledocholithiasis. There was no correlation between the status of gallbladder filling, preexisting cholecystolithiasis, and recurrent stones, but 9 of the 10 patients with recurrent stones had a juxtapapillary diverticulum. Repeated endoscopic treatment was satisfactory in eight patients, and only two patients received cholecystectomy. CONCLUSIONS: EST does not alter gallbladder function in most patients. Juxtapapillary diverticulum may facilitate gallbladder filling after EST, but it is also a possible factor for recurrent choledocholithiasis.

The efficacy of endoscopic sphincterotomy in patients with sphincter of Oddi dysfunction.

BACKGROUND: Dysfunction of the sphincter of Oddi (SOD) is one of the causes of postcholecystectomy syndrome and biliary pain. Endoscopic sphincterotomy (EST) is recommended in some patients refractory to conservative treatment. This study was designed to evaluate the efficacy of, and complications from EST in patients with SOD. METHODS: Between 1990 and 1993, 24 patients clinically diagnosed as having papillary stenosis were treated by endoscopic sphincterotomy. All patients had dilated common bile duct (CBD) in addition to 1) elevation of transaminases and alkaline phosphatase (n = 13); 2) elevation of transaminases and serum amylase (n = 4); 3) normal liver enzymes but delayed biliary emptying on quantitative hepatobiliary scintigraphy (QHS) (n = 7). No CBD stones, organic obstruction or other disorders were found in these patients. RESULTS: EST was successfully performed in 24 patients. One patient had minor hemorrhage and one patient developed pancreatitis after EST. Twenty-two of the 24 patients (91.7%) were symptomatically improved before discharge. Twenty-one patients were regularly followed over a median period of 18 months (range 5-36) after EST. Two patients with symptom had recurrence at five and eight month follow up because of restenosis of papilla; another two patients with recurrent biliary symptoms, but the sphincter of Oddi remained wide open. Seventeen of 21 regularly followed patients were symptom free after the median 18-month follow up. CONCLUSIONS: EST is an effective and safe modality for treatment of sphincter of Oddi dysfunction.

Factors influencing the success rates of endoscopic nasobiliary drainage in treatment of obstructive jaundice.

BACKGROUND: Endoscopic nasobiliary drainage (ENBD) is a safe and effective modality which has been well documented for obstructive jaundice. However, factors predicting success rate of ENBD remain inconclusively. This study analyses those factors and discusses the outcome of patients with obstructive jaundice. METHODS: One hundred and sixteen patients (male 99, female 17; mean age 68.2 years) with obstructive jaundice received ENBD after endoscopic retrograde cholangiogram (ERC) by Olympus JF-lT20 endoscope and 7F Wilson-Cook nasobiliary catheter from Sep. 1990 to Oct. 1993. Bile output (QD), serum bilirubin (BIW), liver biochemistry (QW), bile culture (next day), blood culture (if BT > 38.5 degrees C) were checked until definite treatment or death. Adequate drainage was defined as a daily output of bile more than 200cc, a gradual drop in serum bilirubin and no signs of cholangitis. Factors such as causes of jaundice, obstruction level, serum bilirubin, albumin, juxtapapillary diverticulum (JPD), bacteremia, fever before ERCP and ascites were analyzed. RESULTS: The success rate was 86.2% (100/116) in ERC and 78% (78/100) in ENBD. Adequate biliary drainage was 82.1% (64/78), and serum bilirubin was reduced from 14.3 +/- 8.5 mg% to 7.5 +/- 5.6 mg% within one week. In patients with non-cancerous causes, higher success rate and adequate drainage rate were obtained compared with those with cancerous causes (94.3% vs. 69.2%, p < 0.01 and 88.6% vs. 50.8%, p < 0.01, respectively). In all patients, a higher success rate was achieved at the obstruction level at the common bile duct (CBD) compared with periampullary and hilar levels (90.7% vs 69.2%, p < 0.05 and 90.7% vs 28.6%, p < 0.001, respectively). In patients with cancer as a cause, higher success rate was achieved at CBD level than at hilar level (85% vs 28.6%, p < 0.05). Those patients with cancer and serum bilirubin above 15 mg/dl had a higher failure rate in ENBD. Success rate of ENBD was not related to the presence of JPD, bacteremia or fever before ERCP and serum albumin level. CONCLUSIONS: Factors decreasing the success rates of ENBD were underlying cancerous causes, obstruction level at hilum or periampullary region and serum bilirubin level more than 15 mg%.

In vitro antioxidant properties of the iron chelator pyridoxal isonicotinoyl hydrazone and some of its analogs.

Since there are several problems with desferrioxamine (DFO) therapy, pyridoxal isonicotinoyl hydrazone (PIH) has been studied for more than 10 years as a promising new candidate for iron chelation therapy in iron-overload diseases. Iron chelation could also be helpful for experimental treatment of several other pathologies including rheumatoid arthritis and heart ischemia/reperfusion, due to the generation of oxyradicals and lipid peroxidation mediated by delocalized iron. We demonstrate here that sub-millimolar levels of PIH can inhibit the Fe(III)-EDTA/ascorbate-mediated formation of hydroxyl-like radicals as tested by the release of ethylene from 2-keto-4-methylthiobutyric acid (KMB assay) and the formation of malonaldehyde from 2-deoxyribose damage. PIH could also decrease the rates of Fe(III)-EDTA-mediated oxidation of ascorbate and block the peroxidation of liposomes of rat brain phospholipids induced by ferrous iron-EDTA. In all cases the in vitro antioxidant effectiveness of PIH was comparable to its analogs-including salicylaldehyde isonicotinoyl hydrazone-and to DFO. We conclude that PIH and its analogs are effective new candidates against iron-mediated oxidative stress for use in experimental medicine.

Deoxyribose degradation catalyzed by Fe(III)-EDTA: kinetic aspects and potential usefulness for submicromolar iron measurements.

Iron ions play a central role in .OH radicals formation and induction of oxidative stress in living organisms. Iron-catalyzed .OH radical formation degrades deoxyribose to thiobarbituric acid reactive substances (TBA-RS). This paper analyzes kinetic properties of the Fe(III)-EDTA-catalyzed deoxyribose degradation in the presence of ascorbate. The yield of TBA-RS formation in the presence of EDTA was 4-fold higher than in its absence, contrasting with results reported elsewhere, Cu(II)-EDTA and Fe(III)-citrate were unable to catalyze deoxyribose degradation. The dependence on deoxyribose concentration was fitted to a Lineweaver Burk-like plot and it was calculated that approximately 4.5 mM deoxyribose scavenged half of the .OH radicals formed. The data for Fe(III)-EDTA concentration dependence could also be fitted to a rectangular hyperbolic function. This function was linear up to 1 microM added FeCl3 and this property could be utilized as an assay for the estimation of submicromolar iron concentrations. Submicromolar concentrations of iron could induce measurable yields of TBA-RS. Differences of as little as 0.1 microM Fe(III)-EDTA could be reproducibly detected under optimum experimental conditions, above a consistent background absorbance that was equivalent to 0.35 +/- 0.05 microM Fe(III)-EDTA and represented contaminating iron in the reactants that could not be removed with Chelex-100. The low method determination limit makes the deoxyribose degradation reaction potentially useful as a new, highly sensitive and cost effective assay for iron quantification.

[Preparation and characteristic analysis of monoclonal antibodies against human growth hormone].

Four hybridomas stably secreting monoclonal antibodies (McAbs) against human growth hormone (hGH) have been obtained by fusion of immunized mice spleen cells with myeloma SP2/0 cells. After inoculation of hybridoma cells to BALB/c mice i.p., the ascitic fluids were collected and characterized, the titre of the 4 McAbs being in the range of 0.6-10.0 X 10(5). As determined by Ouchterlony analysis, all the 4 McAbs were IgG1. They varied in affinities, with equilibrium constants from 0.53 X 10(9) to 9.0 X 10(9) L/mol. McAb-1 showed 52.5% cross-reactivity with human placental lactogen (hPL). McAb-2, McAb-3 and McAb-4 displayed no crossreactivity with hPL and human prolactin (hPRL). Antigenic determinants recognized by the 4 McAbs were mapped through their reactions with hGH fragment consisting of residues 1-43, cross-reaction with hPL, hPRL and antibody-antibody competition test. The results showed that the antigenic determinants of the McAbs are not located in the site of hGH comprising residues 1-43 but on the three non-overlapping antigenic sites of hGH. As shown in receptor assay, all the 4 McAbs exhibited specific inhibition on the binding of pregnant rabbit liver GH receptor to 125I-hGH. It seems likely that receptor-binding site is larger than the antigenic determinant or there are more than one site on hGH surface capable of binding to the hormone receptor. The McAbs could only bind with the peak 2 (MW22000) but not the peak 1 (MW 45000) of old 125I-hGH after gel filtration.(ABSTRACT TRUNCATED AT 250 WORDS)