Inclusive K(S);(0)K(S);(0) resonance production in ep collisions at HERA

Inclusive K_{S};{0}K_{S};{0} production in ep collisions at the DESY ep collider HERA was studied with the ZEUS detector using an integrated luminosity of 0.5 fb;{-1}. Enhancements in the mass spectrum were observed and are attributed to the production of f_{2}(1270)/a_{2};{0}(1320), f_{2};{'}(1525) and f_{0}(1710). Masses and widths were obtained using a fit which takes into account theoretical predictions based on SU(3) symmetry arguments, and are consistent with the Particle Data Group values. The f_{0}(1710) state, which has a mass consistent with a glueball candidate, was observed with a statistical significance of 5 standard deviations. However, if this state is the same as that seen in gammagamma-->K_{S};{0}K_{S};{0}, it is unlikely to be a pure glueball state.

Rate of disappearance of circulating endogenous gastrin in dogs

In five awake mongrel dogs, endogenous gastrin was released by continuous irrigation of the antrum with acetylcholine. After 60 minutes of antral perfusion, the entire vascular supply of the antrum was suddenly and totally occluded, and serial samples of peripheral blood were taken for measurement of gastrin. The rate of disappearance of endogenous gastrin was caluclated by standard linear regression analysis; the calculated half-life of endogenous gastrin was 8.62 minutes. Analysis of the data suggests that the disappearance rate of endogenous gastrin could be explained by two distinct half-lives: one of 2.8 minutes (which is similar to the half-time in dogs of both 14- and 17 -amino acid gastrin), and another of 15.4 minutes (which is similar to the half-time of 34 -amino acid gastrin). Physiologically released gastrin is a mixture of three or more molecular forms of gastrin and the half-life of 8.62 minutes probably represents the disappearance half-time of this mixture.

Suppression of gastric secretion and serum gastrin by gastrin antibody

Fourteen dogs received varying doses of antigastrin antibody; after a single dose of 0.07 ml/kg, circulating gastrin levels could not be measured for as long as forty-seven days. Gastric secretion in response to food was not diminished by antigastrin antibody doses as high as 0.07 ml/kg daily for ten days. Larger doses, 0.2 and 0.4 ml/kg, were required to produce a temporary reduction in gastric-stimulated gastric acid secretion. Mucosal levels of gastrin in the antrum, fundus, and duodenum were greatly increased ten days after injection of antigastrin antibody. The therapeutic use of antigastrin antibody to control gastric secretion seems at the present time not feasible because of the scarcity of the antigastrin antibody and because large doses aare required to obtain only a temporary effect.

Interlaboratory reproducibility of gastrin measurements by radioimmunoassay

A collaborative study was conducted to determine interlaboratory variations in the measurement of gastrin by radioimmunoassay (RIA). A kit containing reagents for a communal RIA method, as well as test samples containing different amounts of human synthetic gastrin (SHG I) and test samples of serum from a fasting normal patient admixed with varying volumes of serum from a patient with the Zollinger-Ellison syndrome, was sent to each collaborating investigator. Each investigator was requested to measure the gastrin concentrations in test samples by means of the communal RIA method, as well as the RIA method utilized in his or her laboratory. Use of the communal RIA method resulted in no significant interlaboratory variation in the determination of gastrin concentration in SHG I test samples and a maximum two- to threefold variation in determination of gastrin serum test samples. In contrast, when individual RIA methods were used to measure gastrin concentrations, the amount of SHG I in test samples reported by one laboratory was significantly different than that reported by the other three. In addition, use of different RIA methods resulted in a 2- to 19-fold interlaboratory variation in serum gastrin measurements and the maximum variation was found when the gastrin in normal fasting serum was measured. Increased variations in results, when different RIA methods were used, may be due to differences in preparation and purification of labeled antigen, to differences in separation of bound from free hormone, and to differences in the antibodies themselves.

Natural history and experience with diagnosis and treatment of the Zollinger-Ellison syndrome

With better methods of diagnosis, patients will be identified earlier in the course of their disease and will often have atypical and borderline manifestations of the syndrome. Serum gastrin measurements with calcium and especially with secretin challenge will be the most important method of diagnosis. Any patient with acid hypersecretion who has a high serum gastrin level that does higher on secretin infusion should be considered to have the Zollinger-Ellison syndrome. A firm diagnosis of the Zollinger-Ellison syndrome should be made, if at all possible, prior to operation. At operation, a thorough search of the pancreas, duodenum, stomach, greater and lesser omentum and liver should be made for primary and secondary gastrinomas. If the preoperative data firmly establish the diagnosis of the Zollinger-Ellison syndrome, a total gastrectomy should be carried out even if no primary tumor is found. Similarly, a total gastrectomy should be done even if there are massive hepatic metastases. If total gastrectomy is not performed, the patient is apt to die of complications of acid hypersecretion. The only possible exceptions to the rule of always performing a total gastrectomy are in asymptomatic patients with easily excisable tumors or patients with tumors of the duodenum that are easily excisable, providing that in both instances after the excision of the tumor the output of gastric acid as measured at operation is immediately halted. All possible metastatic tumor tissue should be removed. The more tumor tissue removed, the longer the patient will survive. Metastases should be treated aggressively. They do not disappear after total gastrectomy in our experience, and they may kill patients. Patients should be followed after operation with serial measurements of serum gastrin concentrations and by hepatic scintillation scans and hepatic angiography. If hepatic metastases develop, intrahepatic artery infusions of 5-fluorouracil may slow tumor growth.

Effect of antrectomy and subsequent vagotomy on the serum gastrin response to food in dogs

The effect of food on serum gastrin and gastric acid secretion has been studied in dogs with denervated pouches before and after antrectomy and subsequent vagotomy. A Billroth I anastomosis was used in one group of dogs and a Billroth II in the other. Serum gastrin was measured by radioimmunoassay. In both groups of dogs antrectomy significantly depressed mean basal levels of serum gastrin and abolished the rise in serum gastrin in response to a meat meal. Meal-induced pouch acid secretion was considerably lowered by antrectomy after either Billroth I or Billroth II anastomosis. Vagotomy after antrectomy increased basal levels of gastrin, but did not restore the serum gastrin response to a meat meal in either group of dogs. It is suggested that biologically active forms of gastrin are released from the antrum in response to a meal. Biologically inactive basal levels of gastrin apparently originate from extra-antral sources. The post-vagotomy increase in basal (static) gastrin suggests vagal control of the metabolism of static, extra-antral gastrin.

Depletion of antral gastrin after food in rats

The results of these studies indicate that in fasting rats, there is an abrupt and prolonged rise in circulating gastrin after feeding. This increase in serum gastrin is accompanied by an early (five minutes) diminution in antral gastrin which is followed by slightly higher and more variable antral gastrin values. These findings suggest that feeding triggers the release of gastrin with early depletion of antral gastrin and that, subsequently, gastrin syhthesis and release interact cyclically to maintain antral and serum concentrations of gastrin. Antral, fundic, and duodenal gastrin values in rats are similar to those reported in dogs and cats. The jejunum of the rat contains little, if any, gastrin.

Gastrin release by ethanol in man and in dogs

In man, oral or intravenous administration of ethanol caused a small but definite increase in peripheral serum gastrin concentration (measured by radioimmunoassay). In dogs, perfusion of the antrum with 10% ethanol caused an immediate increase in gastrin levels in the antral venous outflow. Acidification of the perfusate did not totally block the gastrin release from the antrum. Intravenous infusion of ethanol in dogs caused release of gastrin from the antrum.

Extraction of circulating endogenous gastrin by the gastric fundus

The effect of circulatory transit of the gastric fundus on serum levels of endogenous gastrin measured directly by radioimmunoassay has been studied in 14 dogs. Gastrin was measured in samples obtained simultaneously from the arterial inflow and venous outflow of the gastric fundus. During basal conditions, transit of the gastric fundus resulted in no change in gastrin concentration. During periods of stimulated gastrin release from the antrum, nine of the 14 dogs demonstrated a significant gastric acid secretory response. In these dogs there was a significant arteriovenous difference (approximately 30%) in circulating gastrin values. In the remaining five dogs, which did not demonstrate a significant gastric acid secretory response, there was no arteriovenous difference in circulating gastrin values. It is concluded that the gastric fundus is an important site for the inactivation of stimulated levels of circulating gastrin.

Measurement of endogenous release of cholecystokinin by radioimmunoassay

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Effect of nephrectomy on the rate and pattern of the disappearance of exogenous gastrin in dogs

Studies of gastrin metabolism were performed in four dogs before and after nephrectomy. Synthetic human gastrin I was infused for two hours and serum samples were obtained at various times during and after infusion. Serum concentrations of gastrin were measured by radioimmunoassay. A two-compartment model was employed to calculate half-lives under each of four experimental conditions, low and high infusion rates, used both before and after nephrectomy. The model half-life was greatly prolonged after nephrectomy at both infusion rates (from 2.54 min to 5.15 min at the low rate, and from 2.85 min to 7.88 min at the high rate). The metabolic clearance rate, an expression of the rate of catabolism during infusion, decreased significantly after nephrectomy at both infusion rates. These observations indicate that the kidney is an important organ for the catabolism of exogenous gastrin.

The role of thoracic duct lymph in gastrin transport and gastric secretion

The effect of thoracic lymph diversion on gastric secretion has been studied in dogs. In addition, the concentration of gastrin in thoracic duct lymph of nine dogs and two patients has been measured before and during antral stimulation with either food or acetylcholine. The secretory studies do not support the concept that there is a significant gastric secretagogue in thoracic duct lymph. The amount of gastrin carried in thoracic duct lymph as determined by radioimmunoassay is far less than that necessary to evoke a gastric secretory response.

Correlation of the surface pH, histology, and gastrin concentration of gastric mucosa

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