Monitoring of mycotoxin biomarkers in the Czech Republic.

AFM1 was determined in 72 (72%) samples of human urine, range 19-6064 pg/g creatinine, mean 367 pg/g creatinine, median 158 pg/g creatinine and 90% percentile 755 pg/g creatinine in 1997. AFM1 was determined in 46 (43.8%) samples of human urine, range 21-19219 pg/g creatinine, mean 414 pg/g creatinine, median 96 pg/g creatinine and 90% percentile 415 pg/g creatinine in 1998. OTA was determined in 2077 (94.2%) samples of human serum, range 0.1-13.7 µg/L, mean 0.28 µg/L, median 0.2 µg/L and 90% percentile 0.5 µg/L in 1994-2002. OTA was determined in 12 (40%) samples of human kidneys, range 0.1-0.2 µg/kg, mean 0.07 µg/kg, and median 0.05 µg/kg in 2001.

[Monitoring the important mycotoxin biomarkers (ochratoxin A, aflatoxin M1) in the Czech population]. / Stav sledováni významných biomarkeru mykotoxinu (ochratoxinu A, aflatoxinu M1) u populace v Ceské republice.

BACKGROUND: In among mycotoxins, secondary metabolites of toxinogenic moulds, ochratoxin A and aflatoxins occupy a prominent place. These mycotoxins have been--as etiologic agents-- associated with a wide numbers of acute and chronic human diseases including mycotoxicoses like Balkan endemic nephropathy or liver cancer. While the risk of acute toxic effects of ochratoxin A and aflatoxin B1 is usually considered to be minimal in the Czech Republic, the situation is different as far as the risk of the late toxic effects (particularly carcinogenic), which result from a single or repeated intake of low doses of these mycotoxins from foodstuffs is concerned. METHODS AND RESULTS: The presence of ochratoxin A and aflatoxins in human environment has been monitored within the program "Monitoring the health state of the population". As for ochratoxin A, 2206 samples of blood serum were investigated, 2077 (94 %) of them turned out to be positive (with levels > or = 0.1 microg x l(-1)), the average was 0.28 microg x l(-1), the median was 0.2 microg x (l(-1), and the percentile (90%) was 0.5 microg x l(-1). The ochratoxin A levels ranged from 0.1 to 13.7 microg x l(-1) of sera. The presence of ochratoxin A was also analyzed in 30 samples of human kidneys; 12 samples were positive (with levels > or = 0.1 microg l(-2), the average was 0.07 microg x kg(-1), the median was 0,05 microg x kg(-1). As for aflatoxins, in 1997-1998 the presence of aflatoxin M1 was investigated in 205 samples of human urine; 118 samples (58%) were positive (with levels >125 pg x l(-1) of urine). CONCLUSIONS: When calculated to a concentration of creatinine in urine, the average was 391 pg x g(-1), the median was 127 pg x g(-1), and the percentile (90%) was 585 pg x g(-1). The aflatoxin M1 levels ranged from 19 to 19 219 pg x g(-1) of creatinine.

Renal tubular dysfunction and urinary zinc excretion in breast cancer patients treated with anthracycline-based combination chemotherapy.

The survival of breast cancer patients has significantly improved through the treatment with anthracyclines. Although anthracyclines are known to produce renal disease in experimental animals, little is known about the toxicity of anthracyclines at clinically relevant doses in humans. In a previous study on cancer patients we have observed an increase in the urinary activity of N-acetyl-beta-D-glucosaminidase (NAG), an indicator of renal tubular cell dysfunction that was accompanied by increased urinary zinc loss. Because an increase in NAG activity was reported after the treatment with anthracyclines, we hypothesized that an increase in urinary NAG activity in breast cancer patients treated with anthracycline-based regimens will be accompanied by hyperzincuria and hypozincemia. Urinary and serum zinc, urinary NAG and serum creatinine were examined during chemotherapy in 26 breast cancer patients treated with anthracycline-based chemotherapy. A trend for increased NAG activity, as compared to baseline, was observed throughout the first 4 cycles of treatment. NAG activity was significantly elevated compared to pretreatment levels one week after the first, third and fourth dose of chemotherapy. Serum creatinine concentrations decreased significantly after the second cycle of therapy. On the other hand, urinary and serum zinc levels did not change significantly during the treatment. In conclusion, our data confirm the presence of mild renal tubular cell dysfunction in breast cancer patients treated with doxorubicin-based chemotherapy. Increased urinary NAG is accompanied by a decrease in serum creatinine which is consistent with hyperfiltration. These changes are not associated with abnormalities of renal zinc handling or a decrease in serum zinc concentrations.

The dialysis of Ochratoxin A (OTA).

Standard dialysis did not result in a decrease of the OTA level in the blood serum of patients regularly treated by dialysis. Therefore, we examined the effect of dialysis on both OTA bound to the blood plasma proteins and free OTA. We carried out an in vivo experiment to determine OTA levels in the serum of patients in the terminal stage of chronic renal insufficiency (CHRI) before and after dialysis and also in the dialysate in which we did not find OTA. OTA bound to blood plasma proteins did not penetrate the dialysis membrane. In contrast, free OTA during an in vitro experiment with the identical dialyzer (as during the in vivo experiment), easily penetrated the same dialysis membrane.

Increased urinary zinc excretion in cancer patients is linked to immune activation and renal tubular cell dysfunction.

Urinary zinc excretion is known to be increased in cancer patients, but the pathogenesis of this phenomenon remains uncertain. Both skeletal muscle catabolism and renal tubular cell dysfunction have been proposed to explain this observation. We have investigated urinary zinc and N-acetyl-beta-D-glucosaminidase (NAG), an indicator of renal tubular cell dysfunction, as well as serum neopterin, an index of systemic immune activation, in 22 patients with cancer and seven controls. Both serum neopterin and urinary zinc were significantly elevated in cancer patients (15.8 +/- 12.7 versus 7.3 +/- 2.3 nmol l-1 and 1.77 +/- 0.80 versus 1.21 +/- 0.41 mmol mol-1 creatinine, P < 0.02 and P < 0.05, respectively), while NAG was similar in cancer patients and the controls (13.58 +/- 13.80 versus 13.68 +/- 12.19 mu kat mol-1 creatinine). A significant correlation was observed between serum neopterin and urine zinc (rs = 0.5119, P < 0.02), serum neopterin and urine NAG (rs = 0.6761, P < 0.002), and urinary zinc and NAG (rs = 0.6348, P < 0.002). In conclusion, the present data indicate a link between urinary zinc excretion and immune activation as well as renal tubular cell dysfunction. In addition, renal tubular cell dysfunction appears to be linked to immune activation.

Association between renal tubular cell dysfunction and increased urinary zinc excretion in cancer patients.

Although an increase in renal zinc excretion in cancer patients is well documented, the mechanisms involved are still disputed. As recent studies have raised the question of the role of renal tubular cell dysfunction in the elevation of urinary zinc output, we have examined urinary zinc excretion and the excretion of N-acetyl-beta-D-glucosaminidase (NAG), an indicator of tubular cell dysfunction, in 30 patients with cancer, 28 healthy controls and 20 patients with benign non-inflammatory disorders. As expected, urinary zinc excretion was significantly higher in the cancer patients compared with controls and patients with benign disorders (2.64 +/- 3.05 vs. 0.86 +/- 0.36 and 0.89 +/- 0.29 mmol mol creatinine-1, p < 0.001). NAG activity was also elevated (18.9 +/- 20.1 vs. 4.32 +/- 3.33 and 9.99 +/- 9.72 mukat mol creatinine-1, p < 0.001 and p < 0.05, respectively). A significant correlation between urine zinc and NAG was observed in all three groups (rho = 0.73, p < 0.001, rho = 0.55, p < 0.01 and rho = 0.45, p < 0.05, respectively). In conclusion, our data provide additional support for the role of renal tubular cell dysfunction in hyperzincuria in cancer. Urinary zinc measurement may represent an alternative approach to detecting renal tubular dysfunction in human pathology.

Increased urinary zinc and copper excretion in colorectal cancer.

Although several studies have described an increase in urinary zinc output in cancer patients, little attention has been paid to the excretion of copper. In this study, we investigated urinary excretion of zinc and copper, and serum levels of alpha-1 acid glycoprotein, an acute phase protein, in 22 patients with colorectal cancer. Urinary excretion of copper and zinc were significantly increased compared to the reference group (77 +/- 72 vs. 32 +/- 14 mumol/mol creatinine, P < 0.05, and 1.50 +/- 0.62 vs. 0.70 +/- 0.41, P < 0.002, respectively). In addition, a negative correlation was observed between urinary copper and serum alpha-1 acid glycoprotein (rs = -0.5256, P < 0.02). In conclusion, urinary excretion of copper, as well as that of zinc, appears to be elevated in colorectal cancer. The finding of a negative correlation between urinary copper and alpha-1 acid glycoprotein supports the postulated role of the latter in regulating renal glomerular permselectivity.

Urinary zinc excretion and acute phase response in cancer patients.

We investigated urinary zinc and serum levels of C-reactive protein, alpha-1 acid glycoprotein, haptoglobin, transferrin and prealbumin in 55 patients with solid tumors and 20 controls. Urinary zinc, serum C-reactive protein, alpha-1 acid glycoprotein and haptoglobin were significantly higher, and serum prealbumin was significantly lower in cancer patients. A significant positive correlation between urinary zinc and C-reactive protein, alpha-1 acid glycoprotein and haptoglobin, as well as a negative correlation with transferrin and prealbumin were observed. Hyperzincuria in cancer patients appears to be linked to the acute phase response. Our data provide further evidence implicating systemic inflammatory response in increased urinary zinc excretion.

Urinary zinc excretion in patients with different disorders: the acute phase response in the kidney.

While depressed circulating zinc levels constitute a well-characterized part of the acute phase response, relatively little attention has been paid to the changes in urinary zinc excretion, although urine zinc output has been reported to be elevated in various disorders, mainly those known to be accompanied by inflammatory phenomena. In order to assess the significance of urinary zinc loss and its relationship with the acute phase response, zinc concentration was determined by atomic absorption spectrophotometry together with creatinine in urine samples of patients with different disorders. Plasma zinc, C-reactive protein, alpha-1 acid glycoprotein, haptoglobin, prealbumin, transferrin, and iron have also been determined in some patients. In accordance with the results of previous studies, we report an increase in urinary zinc, notably in solid tumors, hematologic malignancies, autoimmune rheumatic disorders, bacterial infections, diabetes mellitus and nephropathy. We also found a significant positive correlation between urinary zinc and acute phase proteins alpha-1 acid glycoprotein (rs = 0.4649, P < 0.005), haptoglobin (rs = 0.4688, P < 0.005) and C-reactive protein (rs = 0.3636, P < 0.025), as well as a negative correlation with plasma zinc (rs = 0.3640, P < 0.025). As the role of lipid peroxidation in renal tubular cell injury has been proposed, the increased urinary levels of zinc, which has antioxidant properties, may be an important protecting mechanism, representing a part of the acute phase response in the kidney.

Neopterin in the diagnosis of disorders associated with immune system activation.

While the knowledge concerning the role of the immune system in many internal disorders has grown rapidly in recent years, there are few methods to assess immune system activation in clinical practice. Measurement of urine neopterin, product of a metabolic pathway controlled by interferon-gamma, has been found useful in many clinical conditions. The present study concerns neopterin excretion in 157 patients with different internal disorders. As expected, we found an increase in urine neopterin in patients with malignant tumors, autoimmune disorders like systemic lupus erythematosus or inflammatory bowel disease, and infections. Elevated neopterin levels were also observed in acute pancreatitis and in acute myocardial infarction. In addition, significant correlations between urine neopterin and zinc and neopterin and copper excretion were found suggesting a physiological role of neopterin as urine antioxidant.

[Excretion of phenol and p-cresol in the urine in fasting obese individuals and in persons treated with total enteral nutrition]. / Vylucování fenolu a p-krezolu mocí u hladovejících obézních a u osob lécených úplnou enterální výzivou.

In the literature it is maintained that phenol and p-cresol are produced in humans in the gut by bacteria from dietary protein. Both substances are absorbed from the small intestine and excreted in the urine. If the urinary output of phenol and p-cresol depends really on the dietary protein intake it should decline to zero values during fasting and correlate with the protein supply into the gut. The objective of the present work was therefore to investigate the urinary phenol and p-cresol excretion in fasting obese subjects (21 fasting subjects, 7 subjects with modified fasts--Nutramine R-350) and in subjects treated by complete enteral nutrition by a nasojejunal tube (8 patients with Crohn's disease, 8 with another disease of the gastrointestinal tract). Phenol and p-cresol in 24-hour urine specimens were assessed by gas chromatography in all four groups always on the 1st, 7th and 14th day. In fasting obese subjects the phenol and p-cresol values did not decline (the difference of values from the assumed zero value is significant z = 0.000055). There was no difference between patients with a complete and modified fast. The phenol and p-cresol values did not correlate mutually, nor with the protein intake, nitrogen balance and cumulated nitrogen balance. There are great individual differences in the urinary phenol and p-cresol excretion and it does not depend on the oral dietary protein intake, as hitherto assumed. It has most probably more complex causes and the decisive factor seems to be the metabolic activity of the intestinal bacterial microflora.

[Urinary excretion of phenol in Crohn disease during total parenteral nutrition]. / Vylucování fenolu mocí u Crohnovy choroby v prubehu totální parenterální výzivy.

Urinary phenol is a product of dietary tyrosine metabolism generated in the gut by bacteria. In our previous study we found in 42 patients with Crohn's disease a significantly higher level of urinary phenol in terminal ileitis and ileal resection when compared with Crohn's segmental colitis. Urinary phenol is believed to be extensively influenced by diet. For this purpose our present paper investigated urinary phenol in Crohn's disease before and after two weeks of total parenteral nutrition. Spectrophotometric analysis of urinary phenol was carried out in 10 patients (7 males, 3 females). They ranged from 24 to 40 (average 34.9) years of age. The patients received on an average 1.45 g of amino acids/kg/day (no tyrosine; 0.022 g of L-phenyl-alanine/kg/day), 25-30 kcal/kg/day (105-125 kJ/kg/day) in non-protein sources of energy, and fat-emulsions (80 g/day) twice a week. There was a significant decrease in the urinary phenol after two weeks of total parenteral nutrition (median 79.5, interquartile range 41.5 to 288.5 mumols/24 hours vs. median 37.5, interquartile range 0-93.5 mumols/24 hours), p = 0.032 using the paired t-test. In two patients with severe involvement of the gut, urinary phenol, though decreased, remained at higher levels (above 300 mumols/24 hours). A significant decrease of the urinary phenol can be explained in particular by exclusion of dietary proteins, although clinical and nutritional improvement was observed, too. However, persisting higher levels of urinary phenol in some patients with serious involvement of the gut may reflect the severity of Crohn's disease.

Lack of nephrotoxicity of styrene at current TLV level (50 ppm).

Biochemical markers of kidney damage were examined in 37 female workers exposed to an average concentration of 225 mg/m3 of styrene. The concentration of mandelic acid in urine was on the average 759 mg/g creatinine. The mean duration of employment of the exposed subjects was 11 years. The results were compared to those obtained in 35 control female workers matched for age and a number of demographic and lifestyle factors and with no history of exposure to organic solvents. No difference was found in the urinary excretion of albumin, beta 2-microglobulin, retinol-binding protein, total proteins, glucose, lysozyme, lactate dehydrogenase and beta-N-acetyl-D-glucosaminidase. The present study provides thus further evidence that exposure to styrene at the current TLV (215 mg/m3) does not entail any detectable risk for the renal function.

[Chromosome aberrations in peripheral blood lymphocytes in workers occupationally exposed to styrene]. / Vysetrení chromozómových aberací v lymfocytech periferní krve zamestnancu profesionálne exponovaných styrénu.

We performed the investigation of the number of chromosomal aberrations in the peripheral blood lymphocytes of 13 women--workers occupationally exposed to styrene. Our set consisted exclusively of women in the age span from 23 to 54 years. Nine of the workers were smokers, 4 of them did not smoke. The control group was represented by 6 women working in the offices of the same factory. The clinical investigation of both the groups of women was performed at the Clinic of occupational diseases. The common physical check-up was combined with the hematological and biochemical tests including the assessment of the mandelinic acid level in the urine. Also the styrene concentration in the working place was measured by the help of the Regional hygiene center. The average working day's concentration of styrene was found to be 225 +/- 89 mg.m-3 ranging from 83 to 366 mg.m-3. From hte total number of 1220 cytogenetically investigated cells in the group of higher risk in 31 of them (2.54% AB.C.) the chromosomal aberration were found. In 27 cases (2.21%) the structural aberrations were involved; mostly the chromatid breaks and four times the chromosomal breaks were present. Four cells were laden by the numeric aberrations (type of 4n). Moreover, there was also checked the number of gaps (total of 9 gaps; 6 of chromatid, 3 chromosomal ones) and the number of satellite association of chromosomes (total of 87). The number of chromosomal aberrations in the exposed group is statistically significantly higher when compared with the control group (1.17% of AB.C.). Due to the restricted volume of the set our results cannot be taken as a confirmation of the relevant factory to be a working place with the higher exposition to genotoxic agents. Nevertheless, concerning the upper limit of spontaneous aberrations in the unladen population reaching maximally 2% we must consider our results to witness the increased occupational hazard.