Physiologic Observations on Patients With External Pancreatic Fistula

Computer modelling of the chemical speciation of caesium, uranium(VI) and neptunium(V) in human duodenal fluids under fasting conditions

A model simulating the human duodenal contents under physiologically realistic, fasting conditions was developed using the joint expert speciation system (JESS) computer program and database and used to investigate the chemical speciation of caesium, uranium(VI) and neptunium(V). Over the pH range 5.0-9.0, and the concentration range 5 x 10(-15) x 10(-5) mol dm(-3), caesium was predicted to occur predominantly as the absorbable free monovalent cation Cs+ (approximately 95%) with species such as CsHPO4- and CsCl representing the remainder. The presence or absence of sulphate at 2.1 x 10(-3) mol dm(-3) did not influence the predicted speciation. Uranium was predicted to be present entirely as a soluble, highly charged species, both in the absence and in the presence of sulphate. Between pH 5.0 and approximately 6.5 the UO2H2(PO4)2(2-) predominated, above this pH carbonate species, either UO2(CO3)4(6-) or, possibly, UO2(CO3)5(8-). At pH 8.0, and in the presence of sulphate, neptunium(V) was predicted to exist solely as the tetrasulphate species, whilst in the absence of sulphate, an array of negatively charged soluble carbonate species predominated. Studies over the pH range 5.0-9.0 predicted the formation of a spectrum of negatively charged carbonate and phosphate species, approximately 40% of the total neptunium was predicted to be present as the electrically net-neutral species NpO2HCO3 at pH6.0, approximately 20% at pH 7.0, approximately 10% at pH 7.5 and approximately 1% at pH 8.0. The observed speciation patterns of uranium and neptunium did not change over the concentration range 5 x 10(-15) - 5 x 10(-5) mol dm(-3) and no solid species were predicted to occur under the conditions simulated. Whether the predicted electrically net-neutral neptunium species or the uranium pentacarbonate species do actually occur under true physiological conditions remains to be established. The observed speciation patterns for caesium and uranium are consistent with the observed absorption of these elements by humans; however, the observations for neptunium appear to be equivocal.

Thermostability of purified human pancreatic alpha-amylase is increased by the combination of Ca2+ and human serum albumin

Pancreatic fluid from a patient with a post operative pancreatic fistula was used to isolate human alpha-amylase by means of acarbose affinity chromatography. Amylase thermostability was measured in 4 solutions: (1) EDTA-dialyzed; (2) dialyzed solution plus 0.15 mmol/l (1.0 g/dl) human serum albumin; (3) dialyzed solution plus 0.25 mmol/l (1.0 mg/dl) calcium ions; and (4) dialyzed solution with both human serum albumin and calcium ions. Amylase activity was measured at predetermined times in samples heated to 60 degrees C. Thermostability was characterized by t1/2, the time to 50% initial amylase enzyme activity. In the dialyzed solution t1/2 was 0.75 +/- 0.19 min. This rose to 1.62 +/- 0.34 min with added human serum albumin, and to 8.24 +/- 0.13 min with added calcium ions. The combination of human serum albumin and calcium ions resulted in a synergistic increase of t1/2 to 180 +/- 26 min. These findings support our contention that human serum albumin, calcium ions and possibly other body fluid constituents must be considered in any utility involving amylase thermostability as a clinically relevant diagnostic marker.

Human pancreatic tissue concentration of bactericidal antibiotics

Pancreatic infection represents the most important cause of fatal outcome in human acute pancreatitis. In a comparative analysis, human pancreatic tissue concentrations of 10 different bactericidal antibiotics were determined in 89 patients undergoing pancreatic surgery. Concentrations of the antibiotics were determined in the blood and pancreatic tissue using high-pressure liquid chromatography. Pancreatic tissue concentrations 120 minutes after intravenous administration were as follows: mezlocillin, 19.0 mg/kg; piperacillin, 20.3 mg/kg; cefotaxime, 9.1 mg/kg; ceftizoxime, 7.9 mg/kg; netilmicin, 0.4 mg/kg; tobramycin, 0.4 mg/kg; ofloxacin, 1.7 mg/kg; ciprofloxacin, 0.9 mg/kg; imipenem, 6.0 mg/kg; metronidazole, 3.5 mg/kg. Three groups of antibiotics were established: group A, substances with low tissue concentrations (netilmicin, tobramycin), which were below the minimal inhibitory concentrations of most bacteria found in pancreatic infection; group B, antibiotics with pancreatic tissue concentrations which were sufficient to inhibit some but not all bacteria in pancreatic infection (mezlocillin, piperacillin, ceftizoxime, cefotaxime); group C, substances with high pancreatic tissue levels as well as high bactericidal activity against most of the germs present in pancreatic infection (ciprofloxacin, ofloxacin, imipenem). These data could serve as the basis for adequate antibiotic prophylaxis or treatment of pancreatic infection.

The penetration of antibiotics into human pancreas

In order to analyse the penetration of two antibiotics (mezlocillin and metronidazole) which cover the spectrum of microorganisms involved in pancreatic infection, we determined their concentration in pancreatic tissue, juice and cyst fluid in 16 patients undergoing pancreatic surgery. In addition, the external pancreatic fistula fluid of one patient was analysed for antibiotic concentration and bacterial counts during a seven-day treatment with mezlocillin, metronidazole and netilmicin (i.v.). Antibiotic concentrations were determined by HPLC between 16 and 210 (median 74) min after i.v. administration of 4 g mezlocillin and 500 mg metronidazole, respectively. The median concentration of mezlocillin was 23.2 (range: 3.1-37.4) mg/kg, 15.9 (range: 4.2-55.0) mg/l and 9.9 (range: 5.2-14.8) mg/l in pancreatic tissue, juice and cyst fluid, respectively. The median concentration of metronidazole was 5.1 (range: 1.8-13.0) mg/kg, 8.5 (range: 3.6-16.2) mg/l and 1.2 (0.9-1.4) mg/l in pancreatic tissue, juice and cyst fluid, respectively. From the fistula patient, seven different bacteria were cultured (five aerobic and two anaerobic isolates); their concentration in fistula fluid ranged from 10(5) to 10(7) CFU/ml. The bacteria sensitive for mezlocillin and metronidazole disappeared after four days of i.v. treatment, whereas the two isolates sensitive for netilmicin showed continuous growth seven days after i.v. treatment. The peak concentrations for mezlocillin, metronidazole and netilmicin in the fistula fluid were 6.8 mg/l, 5.6 mg/l and less than 0.1 mg/l, respectively.

Metal concentrations in human pancreatic juice

Concentrations of 11 metals (cadmium [Cd], lead [Pb], copper [Cu], iron [Fe], manganese [Mn], cobalt [Co], chromium [Cr], nickel [Ni], zinc [Zn], magnesium [Mg], and calcium [Ca]) and protein in human pancreatic juice were studied. Human pancreatic juice was sampled by endoscopic cannulation after administration of secretin (intravenous [i.v.], 1 mu/kg). There were 19 subjects (11 males and 8 females) and the means of their ages were 50.3 yr (male, 20-68 yr) and 52.5 yr (female, 45-64 yr). Diagnoses were: normal, 5; early pancreatic cancer, 9; and chronic pancreatitis, 5. None had symptoms suggestive of disturbances in endocrine and exocrine functions of the pancreas. Concentrations of metals and protein in pancreatic juice did not change significantly between males and females or with pathological changes in the pancreas. Assuming the flow rate of pancreatic juice to be 1500-2000 ml/day, the daily excretions of metals into duodenum via pancreatic juice were calculated as follows (mumoles of metal/day): Cd, 0.012-0.012; Pb, 0.216-0.288; Cu, 6.20-8.26; Fe, 2.34-3.12; Mn, 0.100-0.133; Co, 0.165-0.220; Zn, 7.46-9.94; Cr, 0.084-0.112; Mg, 274.1-365.4; Ni, 1.64-2.18; and Ca, 0.221-0.295. Toxic (Cd and Pb) and essential metals (Cu, Zn, Fe, Mn, Cr, and Ni) are excreted daily into duodenum via pancreatic juice.

Biliary and urinary excretion of metals in humans

Fifteen metals (lead, cadmium, arsenic, inorganic mercury, organic mercury, iron, manganese, magnesium, chromium, zinc, copper, nickel, cobalt, tin, and aluminum) were determined in the hepatic bile and urine collected simultaneously from three Japanese individuals (2 males, 1 female). The presence of these metals was classified as follows: hepatic biliary concentrations were higher than urinary concentrations (lead, arsenic, and iron); urinary concentrations were higher than hepatic biliary concentrations (cadmium, inorganic mercury, tin, cobalt, magnesium, chromium, copper, zinc, and nickel); hepatic biliary concentrations were almost equal to urinary concentrations (manganese and organic mercury); and relationship between hepatic biliary and urinary concentrations changed occasionally (aluminum). Eight essential metals (iron, manganese, magnesium, zinc, chromium, copper, nickel, and cobalt) were detected at considerable concentrations in hepatic bile. Accounting for the daily flow volume of hepatic bile and the reabsorption of these metals, the supplementation of these metals should occur during treatment of diseases accompanied by loss of hepatic bile.

Secretion of beta-lactam antibiotics in pure human pancreatic juice

The secretion of cephalothin and cefoxitin in stimulated pure pancreatic juice was studied in 13 persons after intravenous administration of antibiotics. Of all these studied, three had acute relapsing pancreatitis, five chronic pancreatitis, and five were control subjects. Antibiotic levels were measured in paired pure pancreatic juice and serum samples at fixed time intervals after administration. Cephalothin was detected in very low levels (1 to 1.8 micrograms/ml) in the pure pancreatic juice of four of the six persons studied (3 micrograms/ml). Although therapeutic levels were not obtained in stimulated pure pancreatic juice with either antibiotic, additional studies evaluating antibiotic levels in unstimulated pure pancreatic juice and in pancreatic tissue would be helpful in assessing the role of antibiotic therapy in the treatment of pancreatitis.

In vitro-in vivo evaluation of bacampicillin hydrochloride from microcapsules of water-insoluble and an acid-soluble polymer

Bacampicillin hydrochloride has been microencapsulated to mask its very bitter taste. The objective of the study was to compare the in vitro release and bioavailability of bacampicillin hydrochloride from microcapsules coated with two principally different polymers: a water-insoluble polymer, ethylcellulose, and an acid-soluble polymer, Eudragit E 100. The last mentioned was supposed to have advantages from a bioavailability point of view since this polymer should dissolve rapidly upon reaching the stomach. In vitro release studies were performed in different types of media by using a flow-through cell technique and USP paddle apparatus. The in vivo study was performed on 20 healthy volunteers taking single 400 mg doses of the drug in the two microcapsule suspensions and a reference tablet according to a randomized cross-over design. When standard dissolution fluids were used, the Eudragit E 100-coated microcapsules revealed very rapid dissolution but were greatly dependent on buffer concentration and ionic strength. The ethylcellulose-coated microcapsules released the drug much more slowly than Eudragit E 100 when using standard dissolution fluids. They were also affected by buffer concentration and ionic strength. The reference tablet had a significantly higher bioavailability than the two microcapsule suspensions. In vitro-in vivo correlation was not obtained when using standard dissolution fluids according to USP. However when stimulated intestinal fluid was adjusted to have an ionic strength similar to intestinal fluid, a better in vitro-in vivo correlation was obtained. The Eudragit E 100 polymer did not give better bioavailability than ethylcellulose as a coating polymer on bacampicillin microcapsules.

Effects of morphine on human pancreatic secretion: studies on pure pancreatic juice

Data concerning the effects of morphine on human pancreatic secretion are fragmentary and inconclusive. In the present study, we evaluated the effects of morphine on pure pancreatic secretion in nine subjects with external transduodenal drainage of the main pancreatic duct performed after biliary tract surgery. Intravenous infusion of a small dose of morphine, 40 microgram/kg/h, during pancreatic stimulation with secretin and cholecystokinin, caused a significant increase in volume, bicarbonate, and calcium secretion, and a significant decrease in protein secretion. The stimulatory effect on water and electrolyte secretion was rapid and much more pronounced, reaching about 45-50% of the control levels, whereas the inhibition of protein output was slightly delayed and of lesser magnitude, reaching about 20-25% of the control values. Both effects were long-lasting. The addition of naloxone, potent opiate antagonist, prevented in part the effects of morphine on pancreatic secretion, suggesting that specific opiate receptors might be involved in these effects.

Effect of pancreatitis on ampicillin excretion in pancreatic fluids of dogs

Pancreatic excretion of ampicillin was evaluated in normal dogs and in dogs with induced pancreatis. A 100-mg/kg ampicillin dose administered intravenously induced mean peak serum levels of 100 micrograms/ml, and a 200-mg/kg intravenous dose induced a mean peak serum level of 273 microgram/ml. Ampicillin serum levels did not differ between the group of normal dogs and those with pancreatitis. In normal dogs, the peak pancreatic fluid ampicillin concentration after the 100-mg/kg dose was 0.4 microgram/ml, and that after the 200-mg/kg dose was 2.7 micrograms/ml. In dogs with pancreatitis, the mean peak ampicillin concentration in the pancreatic fluid after the 100 mg/kg dose was 19 micrograms/ml, and that after the 200-mg/kg dose was 38.5 micrograms/ml. Pancreatic fluid ampicillin concentrations were therapeutic in dogs with pancreatitis and subtherapeutic in normal dogs.