Activated charcoal: in vivo and in vitro studies of effect on gas formation

It has been reported that activated charcoal reduces intestinal gas production after ingestion of beans as evidenced by decreased breath hydrogen excretion and decreased passage of flatus. In the present study we assessed the ability of activated charcoal to reduce intestinal gas production by in vitro and in vivo methods. In vitro studies were performed using human fecal homogenates incubated with or without additional carbohydrate. In all studies hydrogen and carbon dioxide production and consumption occurred at similar rates in the charcoal-treated homogenate as compared with the untreated control. The influence of activated charcoal on gas production, in vivo, was studied by double-blind assessment of breath hydrogen excretion and flatus excretion after ingestion of a baked bean meal. No significant difference was observed in breath hydrogen concentration or number of passages of flatus in subjects who ingested 16 capsules of activated charcoal (4 g) as opposed to the placebo. We conclude that activated charcoal does not influence gas formation in vitro or in vivo.

Evaluation of an inhibitor assay to determine serum isoamylase distribution

We tested a technique to distinguish salivary from pancreatic isoamylase using a wheat protein which inhibits salivary isoamylase. The inhibitor technique accurately reflected the preponderance of pancreatic or salivary isoamylase in sera which had been "spiked" with human pancreatic or salivary isoamylase. Comparison of the results of either cellulose acetate electrophoresis or isoelectric focusing showed an excellent correlation (r = 0.99) in 43 hyperamylasemic sera which did not contain macroamylase. Normal values obtained in 160 healthy subjects indicated that pancreatic isoamylase comprised 41 +/- 21% (1 SD) of total serum amylase activity and the upper limit of normal for serum pancreatic isoamylase was 166 IU/liter. The inhibitor assay provides a simple and accurate means of differentiating salivary from pancreatic hyperamylasemia.

A rapid and simple assay to determine if macroamylase is the cause of hyperamylasemia

Macromolecules are known to precipitate selectively in concentrated solutions of polyethylene glycol. This report describes the use of polyethylene glycol 6000 to distinguish macroamylase from normal-sized serum amylase. Preliminary studies indicated that a PEG concentration of 12% and a 10-min incubation at 37 degrees C separated normal serum amylase from macroamylase. Using these conditions, study of 18 macroamylase-containing sera showed precipitation of at least 73% of the amylase activity. In contrast, in 46 normal sera and 16 hyperamylasemic (but not macroamylasemic) sera, less than 52% of the amylase activity was precipitated by polyethylene glycol. This test provides a rapid, simple, and accurate means of determining if macroamylasemia is the cause of hyperamylasemia.

Comparison of trimethoprim-sulfamethoxazole with ampicillin in acute infectious exacerbations of chronic bronchitis: a double-blind crossover study

Two separate acute bacterial exacerbations of chronic bronchitis or chronic asthmatic bronchitis were treated in 20 patients in a double-blind crossover study. One course of treatment consisted of 320 mg of trimethoprim (TMP) plus, 1,600 mg of sulfamethoxazole (SMZ) daily and the other of 2 g of ampicillin daily; each drug was given for 14 days. Patients were observed initially, twice a week during therapy, and weekly after therapy. Observations that were recorded included graded chest symptoms and physical findings, vital signs, pulmonary function, hematologic parameters, and objective sputum measurements (daily volume, purulence, differential quantitative cytology, quantitative bacterial counts, physical properties, levels of lactate dehydrogenase with its isoenzymes, levels of myeloperoxidase, and presence of deoxyribonucleic acid fibers). Both antibiotic regimens were effective in resolving these acute bacterial exacerbations. Paired t-test analysis revealed few and minor differences between TMP-SMZ and ampicillin during therapy, although three patients did not complete TMP-SMZ therapy because of adverse reactions. However, the period between the two bacterial exacerbations was significantly longer after ampicillin therapy. Innovative in this investigation are the study design and the objective quantitative measurements of inflammatory response and bacterial populations in sputum.

Bile acid metabolism in the cirrhotic rat

Bile acid metabolism was studied in rats with cirrhosis induced by carbon tetrachloride (CCl4). Although the typical histologic features of cirrhosis were seen, cholestasis was not present in these animals as evidenced by a normal total serum bilirubin concentration and by a normal hepatic capacity to remove taurocholate infused intravenously. The cirrhotic rats also secreted taurocholate into bile at a normal rate. The total bile salt pool size in the cirrhotic rats was not significantly different from the pool size in normal rats (10.59 +/- 1.19 mumoles per gm. of liver (+/- 1 standard error of the mean) and 10.43 +/- 0.92 mumoles per gm. of liver, respectively). When the bile was drained externally through a chronic bile fistula, the normal rats increased the bile salt synthetic rate approximately 3-fold after 48 hours of drainage. However, the cirrhotic rats failed to significantly increase the synthetic rate for bile salts in response to biliary drainage. The normal rats also had a significant increase in cholic acid synthesis at the maximal synthetic rate, whereas the cirrhotic rats did not. These findings indicate that (when feedback inhibition is removed) CCl4 cirrhotic rats lack the ability to normally increase the activity of 7 alpha-hydroxylase and 12 alpha-hydroxylase, rate-limiting enzymes in the synthesis of bile salts.

Reverse transcriptase from avian myeloblastosis virus

From lots of 20 to 30 g of avian myeloblastosis virus RNA-dependent DNA polymerase was obtained in preparations of purity greater than 95% by using a two-step column chromatographic procedure employing DEAE (DE 52) and carboxymethylcellulose (CM 52.). Yields of RNA-dependent DNA polymerase varied from approximately 20,000 to 35,000 U/g of virus. Specific activity of the enzyme was about 35,000 to 60,000 U/mg of protein. Free of detectable RNase activity, the product exhibited a molecular weight of about 160,000, an isoelectric point of 6.5, and approximately 2 mol of fatty acid per mol of enzyme.

Serum isoamylase measurements in pancreatitis complicating chronic renal failure

This investigation was designed to determine whether serum isoamylase measurements can aid in establishing the diagnosis of acute pancreatitis in renal failure patients. Twenty-two hemodialysis patients were studied, four of whom had documented acute pancreatitis. Total serum amylase and pancreatic isoamylase concentrations were significantly higher (p less than 0.02) in the pancreatitis patients than in the 18 patients without pancreatitis, but there was appreciable overlap between these two groups. In each of the four patients with pancreatitis, the percentage of serum amylase derived from the pancreas (range, 80% to 90%) was well above the highest value (67%) observed in the patients without pancreatitis. These results suggest that determination of the percentage of serum amylase represented by pancreatic isoamylase is of assistance in establishing the diagnosis of acute pancreatitis in renal failure patients.

Protein kinase from avian myeloblastosis virus

A protein kinase associated with purified virions of avian myeloblastosis BAI strain A was partially purified by ion-exchange chromatography and gel filtration. The transfer of phosphate catalyzed by this enzyme required a divalent metal ion and ATP as phosphate donor. GTP could not be substituted for ATP, and the reaction was unaffected by either cyclic AMP or beef-heart protein-kinase inhibitor. Of the virus and nonvirus proteins tested as phosphate acceptors, only acidic proteins were phosphorylated. In particular, purified preparations of reverse transcriptase from avian myeloblastosis virus did not accept phosphate. The enzyme is a basic protein (pI = 9.3), and, on the basis of molecular sieving through Sephadex G-200 and velocity sedimentation on glycerol gradient, the protein kinase has a molecular weight of 45,000.