Measurement of micronucleated erythrocytes and DNA damage during chronic ingestion of phenolphthalein in transgenic female mice heterozygous for the p53 gene.

Phenolphthalein, a common ingredient in nonprescription laxatives and a multisex, multispecies rodent carcinogen, was evaluated under chronic exposure conditions for genotoxicity in transgenic female mice heterozygous for the p53 gene (heterozygous TSG-p53 mice). Phenolphthalein was administered in the diet at 200, 375, 750, 3,000, and 12,000 ppm (corresponding to a time-weighted average of 37, 71, 146, 569, and 2,074 mg/kg/day, respectively) for 6 months (183 days). On days 39, 92, 137, and 183 of treatment, peripheral blood samples were collected and evaluated for the frequency of micronucleated polychromatic and normochromatic erythrocytes (MN-PCE and MN-NCE, respectively), the percentage of PCE (%PCE) among total erythrocytes, and the extent of DNA damage (single strand breaks, alkali labile sites, DNA crosslinking) in leukocytes. In addition, the extent of DNA damage was evaluated in liver parenchymal cells sampled from mice at the end of the 6-month treatment period. DNA damage was evaluated using the alkaline (pH > 13) Single Cell Gel (SCG) assay. In addition, using a modified SCG technique, the frequencies of leukocytes and liver parenchymal cells with extremely low molecular weight DNA (indicative of apoptosis and/or necrosis) were determined. At each sample time, phenolphthalein induced a highly significant, dose-dependent increase in the frequency of MN-PCE and MN-NCE and in %PCE. Maximal induction of MN-PCE and %PCE decreased with increasing treatment duration, most likely due to a treatment duration-dependent decrease in the relative amount of ingested phenolphthalein. A comparative analysis of the kinetochore status of MN in erythrocytes sampled from control mice and mice ingesting phenolphthalein at 12,000 ppm for 183 days indicates that the induced MN resulted predominantly but not exclusively from numerical chromosomal damage. The analysis for increased levels of DNA damage in blood leukocytes was inconclusive, with a small but statistically significant increase in DNA migration on days 39 and 137 but not on days 92 and 183. The extent of DNA migration in liver parenchymal cells sampled from mice at the end of treatment was not altered significantly. The frequencies of apoptotic and/or necrotic leukocytes and liver parenchymal cells were not increased among mice ingesting phenolphthalein. The lowest effective dose at which a significant genotoxic response (i.e., the induction of MN-NCE) was detected was 200 ppm, the lowest dose tested in this study. This dose in mice is comparable to doses (on a mg/m2 basis) experienced by humans.

Therapeutic modalities for mechanical cleansing of the colon.

Mechanical cleansing of the colon is an accepted standard of practice prior to colon surgery, and endoscopic and radiographic procedures. Cleansing the bowel prior to these procedures increases the accuracy of the diagnostic procedures and decreases the morbidity and mortality following surgery, where fecal contamination is a concern. Mechanical cleansing agents are sometimes used for acute constipation, but because of the extent and harshness of the evacuation they induce, and because of their adverse effects, they are not used for long-term management of constipation. Dosages vary among products, procedures, and individuals. Manufacturer guidelines should be consulted for proper dosing and administration.

Renal failure associated with laxative abuse.

Eating disorder patients often abuse laxatives in an attempt to purge excess food. Laxative abuse can cause hypokalemia and volume depletion. Hypokalemia, in turn, can lead to rhabdomyolysis. Laxative-induced hypokalemia and volume depletion have been previously reported to cause renal insufficiency, but not severe enough to require hemodialysis. A 27-year-old woman with a long history of laxative abuse presented with severe renal failure associated with hypokalemia and volume depletion. She required acute hemodialysis for worsening acidosis (pH 7.05) despite assisted ventilation. A prior episode of hypokalemic rhabdomyolysis at age 23 had resulted in only mild renal insufficiency. Her later episode of severe renal failure was linked to profound volume depletion (blood urea nitrogen 135 mg/dl). This patient calls attention to a potentially life-threatening complication of laxative abuse and indicates that volume depletion can exacerbate laxative-associated renal failure.

Laxative use not a risk for colorectal cancer: data from the Melbourne Colorectal Cancer Study.

Commercial laxative use as a risk factor in colorectal cancer was investigated as one part of a large population based epidemiological study of colorectal cancer incidence, aetiology and survival "The Melbourne Colorectal Cancer Study", conducted in Melbourne, Australia. Commercial laxative use was similar in 685 colorectal cancer patients and 723 age/sex matched community based controls. Also, when laxatives were subdivided into various groups containing anthraquinones, phenolphthalein, mineral salts and others, previous laxative intake was similar between cases and controls. Previous use of anthraquinone laxatives and of phenolphthalein containing laxatives was not associated with the risk of colorectal cancer.

Diagnosis of magnesium-induced diarrhea.

BACKGROUND: There is no specific method of diagnosing magnesium-induced diarrhea. Therefore, the frequency and clinical importance of diarrhea caused by magnesium are unknown. The purposes of this study were to establish a method for diagnosing magnesium-induced diarrhea and to apply it to patients with chronic diarrhea. METHODS: We measured fecal output of soluble magnesium and fecal magnesium concentration in 19 normal subjects with formed stools (15 collection periods), with non-magnesium-induced diarrhea (36 collection periods), and with diarrhea induced by magnesium hydroxide alone (11 collection periods) or in combination with phenolphthalein (3 collection periods), and in 359 patients with chronic diarrhea. RESULTS: The upper limits of fecal output of soluble magnesium and fecal magnesium concentration in normal subjects were 14.6 mmol per day and 45.2 mmol per liter, respectively. When normal subjects had diarrhea due to the ingestion of magnesium hydroxide alone or in combination with phenolphthalein, fecal magnesium output was always abnormally high. For each millimole increase in fecal magnesium output, fecal weight increased by approximately 7.3 g. The fecal magnesium concentration was very high when magnesium was the only cause of diarrhea but only moderately elevated when diarrhea was induced by magnesium hydroxide plus phenolphthalein. Biochemical and clinical evidence indicated that excessive ingestion of magnesium was an important cause of chronic diarrhea in 15 of the 359 patients with chronic diarrhea (4.2 percent), if not the only cause. CONCLUSIONS: Quantitative fecal analysis for soluble magnesium is an accurate method of diagnosing magnesium-induced diarrhea. Some patients with chronic diarrhea ingest excessive amounts of magnesium (in antacids or food supplements), and physicians may fail to discover this before embarking on an expensive and invasive diagnostic evaluation.

Drug metabolism and metabolite transport in the small and large intestine: experiments with 1-naphthol and phenolphthalein by luminal and contraluminal administration in the isolated guinea pig mucosa.

The metabolism and metabolite transport of the monophenol 1-naphthol (I) and the diphenol phenolphthalein (II) have been studied in a symmetrical setup of the isolated jejunal and colonic mucosa from the guinea pig (Lauterbach 1977). In both tissues, the main metabolites of I were its sulphoconjugate and glucuronide, but the rate of metabolism, relative proportion of the metabolites and their distribution pattern varied with tissue and drug administration side in the following manner: By luminal administration (50 nmol/ml) in the jejunum, the metabolism was nearly complete within 45 min., more sulphate (1.5-3x) than glucuronide was formed, and both metabolites were predominantly transferred back to the lumen. By blood-side administration, the metabolism was less complete due to a significant decrease of the sulphated fraction. In consequence, more glucuronide (1.5-3x) than sulphate was formed. Moreover, the efflux pattern of the metabolites changed completely; the greater part of the glucuronide fraction now being conveyed to the blood side, whereas the sulphate tended to distribute in a 1:1 fashion on the lumen and blood side. The colonic mucosa behaved in a dissimilar way, since neither I metabolism nor metabolite efflux pattern in this tissue was influenced significantly by drug administration side. More sulphate (1.5-3x) than glucuronide was formed by both routes, and the metabolite distribution was similar to that observed by blood side administration in the jejunum. The changes described above were associated with changes in tissue accumulation of free I and metabolites; accumulation of I by luminal administration in jejunum was insignificant and that of the metabolites small. The main change caused by a higher concentration of I (130 nmol/ml) was a decrease in the sulphated fraction in the colon. II was metabolized at a slower rate than I, and a significant tissue accumulation of free II was observed in all instances. The monoglucuronide was the main metabolite. Only minor amounts of II monosulphate were formed, making its distribution pattern difficult to ascertain. The distribution of II monoglucuronide on the other hand was generally similar to that described for its I analogue.

Radiopaque contrast media XXXI-Glucoside conjugation of iodophthalein in rabbit.

Report is given on the identification of the metabolites of the iodophthalein sodium (TIP) in rabbit. After i.v. administration two meabolites (S1 and S2) were excreted mostly in the bile, but both were also found in the urine. The TIP glucoronide (S1) is formed in much greater yield than the glucoside (S2). This latter is a further example of glucoside conjugation in mammals.

A model system for investigating the biliary excretion of an anion in the rat.

1. The biliary excretion of phenolphthalein di[35S]sulphate was studied in rats. 2. The conjugate was administered by continuous infusion at rates of 3, 4.5, 6, 9 and 12 mug/min, and kinetic analysis of the rate of biliary excretion was consistent with a two-compartment open-model system. 3. The results obtained after single injections of the ester were also consistent with the model. 4. An essential feature of the model is the presence of a compartment into which the ester may pass as an alternative to direct excretion via the bile. 5. It is suggested that such a compartment may be located within the liver.