Acidic urine pH is associated with elevated levels of free urinary benzidine and N-acetylbenzidine and urothelial cell DNA adducts in exposed workers

We evaluated the influence of urine pH on the proportion of urinary benzidine (BZ) and N-acetylbenzidine present in the free, unconjugated state and on exfoliated urothelial cell DNA adduct levels in 32 workers exposed to BZ in India. Postworkshift urine pH was inversely correlated with the proportions of BZ (r = -0.78; P < 0.0001) and N-acetylbenzidine (r = -0.67; P < 0.0001) present as free compounds. Furthermore, the average of each subject's pre- and postworkshift urine pH was negatively associated with the predominant urothelial DNA adduct (P = 0.0037, adjusted for urinary BZ and metabolites), which has been shown to cochromatograph with a N-(3'-phosphodeoxyguanosin-8-yl)-N'-acetylbenzidine adduct standard. Controlling for internal dose, individuals with urine pH < 6 had 10-fold higher DNA adduct levels compared to subjects with urine pH > or = 7. As reported previously, polymorphisms in NAT1, NAT2, and GSTM1 had no impact on DNA adduct levels. This is the first study to demonstrate that urine pH has a strong influence on the presence of free urinary aromatic amine compounds and on urothelial cell DNA adduct levels in exposed humans. Because there is evidence that acidic urine has a similar influence on aromatic amines derived from cigarette smoke, urine pH, which is influenced by diet, may be an important susceptibility factor for bladder cancer caused by tobacco in the general population.     

Exposure to glycols and their renal effects in motor servicing workers

Ten car mechanics frequently exposed to glycol-based cooling liquids were followed during a workshift. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were measured. The car mechanics gave urine samples after the workshift and their excretion of ethylene glycol, propylene glycol, oxalic acid, calcium and ammonia was analysed and compared to that of unexposed office workers. Urinary succinate dehydrogenase activity and glycosaminoglycans were also measured in both groups. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were negligible. Urinary ethylene glycol excretion in exposed workers was significantly higher than that in unexposed workers, but propylene glycol excretion was at the same levels as in controls. In the exposed group, the excretion of the end metabolite of ethylene glycol, oxalic acid (47 +/- 11 mmol/mol creatinine, mean +/- SD, n = 10) differed slightly from that of controls (36 +/- 14 mmol/mol creatinine, mean +/- SD, n = 10). Urinary excretion of ammonia was higher among exposed workers than office workers. The excretion of calcium did not differ from that of controls. A marginally decreased urinary succinate dehydrogenase activity was found in the exposed men. The excretion of glycosaminoglycans was significantly lower in exposed workers. Therefore, it seems that ethylene glycol is absorbed by skin contact. The internal body burden is associated with oxaluria and increased ammoniagenesis typical of chronic acidosis.     

Reproductive hormone profile among pesticide factory workers

Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels, as well as urinary levels of FSH, LH, and E1C, a metabolite of testosterone, were measured to investigate the adverse reproductive effects of organophosphate pesticides among Chinese factory workers who were occupationally exposed to ethylparathion and methamidophos. Thirty-four exposed workers were randomly chosen and recruited from a large pesticide factory, and 44 unexposed workers were selected from a nearby textile factory. A quantitative pesticide exposure assessment was performed among a subset of the exposed and unexposed workers. Information on potential confounders was collected in an interview. A single blood sample was collected at the end of a work shift, when each subject also donated a semen sample. Three first-voided urine samples were collected from each worker on 3 consecutive days. Urinary p-nitrophenol level at 1 hour after the work shift correlated with serum (r = 0.71, P < 0.01) and urinary (r = 0.51, P = 0.04) FSH levels. Stratifying by the subjects' exposure status, we found a significant negative correlation among the exposed group between urinary FSH level and sperm count (r = -0.61, P < 0.01) and between urinary FSH level and sperm concentration (r = -0.53, P = 0.03). Pesticide exposure alone was significantly associated with serum LH level (beta [coefficient of exposure effect] = 0.79; 95% confidence interval [CI] = 0.42, 1.16) but not with serum FSH or testosterone or with any urinary hormone levels. With adjustment for age, rotating shift work, current cigarette smoking, and current alcohol consumption, exposure significantly increased the serum LH level by 1.1 mIU/mL (95% CI = 0.34, 1.82). Meanwhile, the serum FSH level was slightly elevated (beta [coefficient of exposure effect] = 1.38; 95% CI = -0.09, 2.85) and the serum testosterone level was decreased (beta = -55.13; 95% CI = -147.24, 37) with increased pesticide exposure. Age and rotating shift work appeared to act as confounders. We conclude that organophosphate pesticides have a small effect on male reproductive hormones, suggestive of a secondary hormonal disturbance after testicular damage.     

Detection of 8-hydroxydeoxyguanosine, a marker of oxidative DNA damage, in white blood cells of workers occupationally exposed to styrene

Styrene-7,8-oxide (SO), the major in vivo metabolite of styrene, is a genotoxic compound and a potential carcinogenic hazard to occupationally exposed workers. The aim of the present work was to investigate the ability of styrene exposure to induce formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in white blood cells (WBC) of boatbuilders occupationally exposed to styrene. The study of these adducts was conducted to see if styrene exposure can cause oxidative damage of DNA. The 8-OHdG/10(5) dG ratio from 17 styrene-exposed workers showed significant increases (mean +/- SD, 2.23 +/- 0.54, median 2.35, P < 0.001) in comparison to the controls (1.52 +/- 0.45, median 1.50). However, 11 out of 17 workers who were between the ages of 32 and 60 years and had been occupationally exposed to styrene for > 10 years showed higher 8-OHdG/10(5) dG ratios (2.31 +/- 0.62, median 2.37) in comparison to 6 workers with < 6 years of occupational styrene-exposure (2.11 +/- 0.36, median 2.05; P > 0.05, no significant difference between the two groups of workers). The studies presented here provide an indication that styrene exposure can result in oxidative DNA damage.     

Anti-benzo[a]pyrene diolepoxide--DNA adduct levels in peripheral mononuclear cells from coke oven workers and the enhancing effect of smoking

The level of (+/-)-r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE) bound to DNA of lymphocytes plus monocytes in 39 coke oven workers exposed to polycyclic aromatic hydrocarbons (PAH) and 39 non-exposed persons (controls) were investigated, each of the groups consisting of smokers and non-smokers. The adduct level was measured by an improved HPLC/fluorescence method (Rojas, M., Alexandrov, K., van Schooten, F. J., Hillebrand, M., Kriek, E. and Bartsch, H., Carcinogenesis, 15, 557-560, 1994) through the release of the corresponding benzo[a]pyrene (B[a]P) tetrols. The anti-BPDE-DNA adduct was detected in 51% of coke oven workers exposed to PAH and in 18% of the non-exposed (control) subjects. The mean level of anti-BPDE-DNA adducts/10(8) nucleotides in coke oven workers (15.7 +/- 37.8) was approximately 8 times higher than in non-exposed subjects (2.0 +/- 8.7). The interindividual variation of adduct levels was approximately 100-fold in coke oven workers and approximately 50-fold in controls respectively. Smokers in the exposed group had 3.5 times more DNA adducts than non-smokers. With the exception of one non-smoker with very high adduct levels (52.8 adducts/10(8)), the control subjects showed the presence of barely detectable adducts in only 16% of the samples examined. The increased in vivo formation in some smokers and high variability of anti-BPDE-DNA adducts in coke oven workers suggests variations in genetically controlled activation/inactivation reactions of PAH metabolism.     

The usefulness of three biallelic restriction fragment length polymorphisms versus a polymorphic dinucleotide tandem repeat polymorphism at the low-density-lipoprotein receptor gene locus for diagnosis of familial hypercholesterolemia

The DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) has been widely used as a biomarker for oxidative stress. Bulky DNA adducts, which are detectable by the 32P-postlabelling method, provide evidence for exposure to and metabolic activation of large, mainly apolar compounds, e.g. polycyclic aromatic hydrocarbons. We determined both types of adducts in placental tissues of 30 term pregnancies and related the adduct levels to the exposure to tobacco smoke and the plasma antioxidant status. Urine and plasma continine concentrations were used to select 10 nonsmokers, 9 nonsmokers exposed to environmental tobacco smoke (ETS) and 11 smoking women. Placental levels of 8-OHdG were 0.84 +/- 0.11, 0.90 +/- 0.21 and 0.83 +/- 0.20/10(5) deoxyguanosine bases (dG) for nonsmokers, nonsmokers exposed to ETS and smokers, respectively. The differences between the groups were not significant. Smoking women had significantly lower plasma vitamin C and beta-carotene concentrations than nonsmoking women or nonsmoking women exposed to environmental tobacco smoke. The 8-OHdG adduct level in placental DNA was inversely correlated with the plasma vitamin E concentration (r = -0.47, P < 0.05). There was no association between placental 8-OHdG adducts and vitamin A, C and beta-carotene in plasma. In total, 15 different adducts could be identified in the 30 placenta samples by the 32P-postlabelling method. There was a strong inter-individual variation in both the number of adducts and adduct intensities. No smoking-related or vitamin-related effects on adduct patterns or intensities were found. Our findings suggests that, within the limits of the methods used, tobacco smoke exposure during pregnancy does not lead to a measurable increase in placental DNA adduct levels and that vitamin E appears to have a protective effect on placental 8-OHdG formation.     

Pilot study of free and conjugated urinary mutagenicity during consumption of pan-fried meats: possible modulation by cruciferous vegetables, glutathione S-transferase-M1, and N-acetyltransferase-2

Epidemiological and experimental evidence indicates that consumption of fried meats in conjunction with certain genotypes of phase I and II metabolism genes poses an elevated risk for colorectal cancer. Parallel to this, the consumption of cruciferous vegetables is associated with a reduced risk of colon cancer. Therefore, we designed a 6-week pilot feeding study to evaluate the effect of these variables on urinary mutagenicity, which is a biomarker associated with fried-meat consumption. Eight subjects were fed fried meats daily for six weeks; four ate cruciferous vegetables, and four ate non-cruciferous vegetables. Urinary mutagenicity was evaluated in the presence of S9 in strain YG1024 of Salmonella, which is a frameshift strain that overproduces acetyltransferase. C18/methanol extracts of 24-h urines collected once each week were tested unhydrolyzed (free mutagenicity) and hydrolyzed (total mutagenicity); the difference between the two was the conjugated mutagenicity. Although not significant, the levels of conjugated urinary mutagenicity doubled among crucifera consumers and decreased to 30% of the initial levels among non-crucifera consumers, suggesting the possibility that crucifera may enhance the level of conjugated urinary mutagenicity resulting from consumption of fried meats. Such an effect would be consistent with the documented ability of cruciferous vegetables to induce phase II enzymes. The NAT2 rapid phenotype was significantly associated with approximately 2-fold increases in conjugated (p = 0.05) and total (p = 0.004) urinary mutagenicity relative to NAT2 slow subjects, consistent with the elevated risk confirmed by the NAT2 rapid phenotype for colorectal cancer among meat consumers. An approximately 2-fold increase in urinary mutagenicity among the GSTM1- subjects relative to the GSTM1+ subjects approached significance for free (p = 0.18) and total (p = 0.13) urinary mutagenicity. This is the first report on (a) the mutagenicity of hydrolyzed urine, which was consistently more mutagenic than unhydrolyzed urine; (b) the potential enhancement of conjugated urinary mutagenicity by crucifera; and (c) the association of the rapid NAT2 and possibly the GSTM1- phenotype with elevated levels of fried meat-associated urinary mutagenicity.     

Inductively coupled plasma mass spectroscopy quantitation of platinum-DNA adducts in peripheral blood leukocytes of patients receiving cisplatin- or carboplatin-based chemotherapy

Platinum-DNA adducts can be assayed in peripheral blood leukocytes by means of atomic absorption spectroscopy and ELISA, and high adduct levels have been correlated previously with favorable clinical response to platinum-based chemotherapy. Our purpose was to study adduct formation in peripheral blood leukocytes by means of a new method, inductively coupled plasma mass spectroscopy (ICP-MS), and to correlate adduct formation with clinical response and toxicity. Platinum (Pt)-DNA adducts were measured by means of ICP-MS in leukocytes of 66 patients receiving a cisplatin- or carboplatin-based chemotherapy, collected either before the beginning of treatment and incubated in vitro with cisplatin or 1 and 24 h after the administration of drug to the patient. The Pt-DNA adduct level in leukocytes from patients exposed to drug in vitro was 14.33 +/- 14.71 fmol/microgram DNA (mean +/- SD), which was not significantly different from the value of 23.4 +/- 19.53 fmol/microgram DNA observed in leukocytes from nine healthy volunteers. In samples collected after the administration of chemotherapy, Pt-DNA adducts ranged from 1.91 +/- 3.59 fmol/microgram DNA (mean +/- SD) at the 1-h time point to 2.61 +/- 3.35 fmol/microgram DNA at 24 h (P > 0.05). Adduct levels in leukocytes exposed in vitro did not correlate with adduct levels from patients treated with cisplatin-based chemotherapy (r = 0.085 and 0.011 at 1 and 24 h, respectively). At 24 h, adduct levels in patients receiving cisplatin (3.15 +/- 3.64 fmol/microgram DNA, mean +/- SD) were significantly higher (P = 0.02) than those observed in patients treated with standard dose carboplatin (0.57 +/- 0.73 fmol/microgram DNA) and also higher than those in patients receiving high-dose carboplatin (1.18 +/- 1.06 fmol/microgram DNA), although the latter difference did not reach statistical significance (P = 0.071). No differences in adduct levels (mean +/- SD) were evident between patients responsive (3.23 +/- 3.51 fmol/microgram DNA) and nonresponsive (2.34 +/- 3.01 fmol/microgram DNA) to chemotherapy. In the homogeneous group of patients treated with combination of cisplatin and 5FU, received dose intensity, hemoglobin decrease, and posttreatment creatinine could not be linked with the extent of leukocyte adduct formation. The data presented here demonstrate that ICP-MS allows the detection of adducts in patients treated with cisplatin or carboplatin and suggest that adduct formation in leukocytes is not a major determinant of response or toxicity.     

DNA adduct formation in the bone marrow of B6C3F1 mice treated with benzene

We used P1-enhanced 32P-postlabeling to investigate DNA adduct formation in the bone marrow of B6C3F1 mice treated intraperitoneally with benzene (BZ). No adducts were detected in the bone marrow of controls or mice treated with various doses of BZ once a day. After twice-daily treatment with BZ, 440 mg/kg, for 1 to 7 days, one major and two minor DNA adducts were detected. The relative adduct levels ranged from 0.06-1.46 x 10(-7). In vitro treatment of bone marrow from B6C3F1 mice with various doses of hydroquinone (HQ) for 24 h also produced three DNA adducts. These adducts were the same as those formed after in vivo treatment of bone marrow with BZ. Co-chromatography experiments indicated that the principal DNA adduct detected in the bone marrow of B6C3F1 mice was the same as that detected in HL-60 cells treated with HQ. This finding suggests that HQ may be the principal metabolite of BZ leading to DNA adduct formation in vivo. DNA adduct 2 corresponds to the DNA adduct formed in HL-60 cells treated with 1,2,4-benzenetriol. DNA adduct 3 remains unidentified. After a 7-day treatment with BZ, 440 mg/kg twice a day, the number of cells per femur decreased from 1.6 x 10(7) to 0.85 x 10(7), indicating myelotoxicity. In contrast, administration of BZ once a day produced only a small decrease in bone marrow cellularity. These studies demonstrate that metabolic activation of BZ leads to the formation of DNA adducts in the bone marrow. Further investigation is required to determine the role of DNA adducts and other forms of DNA damage in the myelotoxic effects of exposure to BZ.     

Ovarian sensitivity to exogenous gonadotrophins in phenobarbital treated unilaterally ovariectomized albino rats

To evaluate platelet activity in patients with non-insulin-dependent diabetes mellitus (NIDDM), we measured the mean platelet volume (MPV) and 24-hour urinary excretion of 11-dehydro-thromboxane B2 (11-dTXB2) and 6-keto-prostaglandin F1 alpha (6-kPGF1 alpha), stable metabolites of thromboxane A2 and prostacyclin, respectively. The MPV of the 103 subjects in the NIDDM group were 10.72 +/- 0.82 fl for males and 10.52 +/- 1.01 fl for females (mean +/- SD), significantly higher than those of normal controls (9.95 +/- 0.75 fl for males and 9.84 +/- 0.72 fl for females). The MPV of patients with NIDDM showed positive correlations with fasting plasma glucose level and HbA1c (r = 0.234, P < 0.05; r = 0.267, P < 0.01, respectively). The urinary excretion of 11-dTXB2 was greater in the NIDDM group (7.58 +/- 4.42 micrograms/day for males and 5.65 +/- 2.38 micrograms/day for females) than in the normal controls (4.61 +/- 2.31 and 3.83 +/- 1.60, respectively), suggesting that the synthesis of thromboxane A2 by platelets may be accelerated in vivo in patients with NIDDM. The urinary 6-kPGF1 alpha was not different between the NIDDM group and normal controls among the males, but was greater in the NIDDM group among the females. As MPV showed a positive correlation (r = 0.364, P < 0.05) with urinary excretion of 11-dTXB2, MPV may be related to platelet activity. These findings suggest that the platelets of patients with NIDDM may be in a hyperactive state.     

Concentration-dependent block of sodium current in guinea pig ventricular myocytes by a class III antiarrhythmic agent, MS-551

The 32P-post-labelling assay for DNA adduct quantification gives the opportunity to examine endogenous exposure to DNA reactive compounds. Most human biomonitoring studies applied white blood cells (WBC) or cells obtained by broncho-alveolar lavages (BAL) as source of DNA, but still it is not clear what cell type represents the most reliable indicator for exposure to cigarette smoke-associated genotoxins. At first, we examined DNA adduct levels by means of nuclease P1 (NP1) enriched 32P-post-labelling in separated WBC subpopulations after in vitro incubations for 18 h with 10 microM benzo[a]pyrene (B[a]P). DNA adduct levels were highest in monocytes (10.7 +/- 2.9 adducts/10(8) nucleotides, n = 8), followed by lymphocytes (5.9 +/- 1.7, n = 8), and granulocytes (0.5 +/- 0.2, n = 8). Secondly, aromatic-DNA adduct levels were determined in BAL cells and WBC-subsets from (non-)smoking volunteers. In smoking individuals, adduct levels were in the ranking order: BAL cells (3.7 +/- 1.0, n = 5) > monocytes (2.0 +/- 0.5, n = 8) > or = lymphocytes (1.6 +/- 0.4, n = 8) > granulocytes (0.8 +/- 0.2, n = 8) by NP1-enrichment and monocytes (9.0 +/- 3.2, n = 5) > or = lymphocytes (8.0 +/- 2.1, n = 6) > granulocytes (2.1 +/- 0.3, n = 7) by butanol-enriched 32P-post-labelling. Aromatic-DNA adduct levels were significantly higher in WBC-subsets of smokers as compared with non-smokers, except for DNA adducts in granulocytes using butanol enrichment. Thirdly, dose-response relationships were investigated in mononuclear white blood cells (MNC, i.e. monocytes plus lymphocytes) and BAL-cells of a larger group of smoking individuals (n = 78). Adduct levels in MNC were related to daily exposure to cigarette-tar (r = 0.31, P < 0.01). Adduct levels in BAL cells seemed to be correlated with pack-years, but after correction for age this relationship was lost. Butanol extraction resulted in 5-6-fold higher DNA adduct levels in MNC, whereas butanol extraction of BAL-DNA of the same individuals yielded only 2-fold higher adduct levels. The two enrichment procedures of 32P-post-labelling were correlated in BAL cells (r = 0.86, P < 0.001, n = 12). We conclude that particularly MNC are good surrogates for the detection of smoking-related DNA adducts.     

Determination of glycyrrhizic acid and 18-beta-glycyrrhetinic acid in biological fluids by micellar electrokinetic chromatography

Human urine is known to contain substances that strongly inhibit bacterial mutagenicity of aromatic and heterocyclic amines in vitro. The biological relevance of these anti-mutagens was examined by comparing levels of tobacco-related DNA adducts in exfoliated urothelial cells from smokers with the anti-mutagenic activity in corresponding 24-h urine samples. An inverse relationship was found between the inhibition of PhIP-mutagenicity by urine extracts in vitro and two DNA adduct measurements: the level of the putatively identified ABP-dG adduct and the total level of all tobacco-smoke-related carcinogen adducts including those probably derived from PhIP. These substances appear to be dietary phenolics and/or their metabolites because (i) the anti-mutagenic activity of urine extracts (n=18) was linearly related to their content in phenolics; (ii) the concentration ranges of these substances in urine extracts were similar to those of various plant phenols (e.g., quercetin, isorhamnetin) for which an inhibitory effect on the liver S9-mediated mutagenicity of PhIP was obtained; (iii) treatment of urines with beta-glucuronidase and arylsulfatase enhanced both anti-mutagenicity and the levels of phenolics in urinary extracts; (iv) urinary extracts inhibited non-competitively the liver S9-mediated mutagenicity of PhIP as did quercetin, used as a model phenolics. Onion, lettuce, apples and red wine are important sources of dietary flavonoids which are probably responsible for the anti-mutagenicity associated with foods and beverages. After HPLC fractionation of urinary extracts, the distribution profile of anti-mutagenic activity corresponded roughly to that of onion and wine extract combined. Overall, our study strongly suggests that smokers ingesting dietary phenolics, probably flavonoids, are partially protected against the harmful effects by tobacco carcinogens within their bladder mucosal cells.     

Increased formation of distinct F2 isoprostanes in hypercholesterolemia

BACKGROUND: F2 isoprostanes are stable, free radical-catalyzed products of arachidonic acid that reflect lipid peroxidation in vivo. METHODS AND RESULTS: Specific assays were developed by use of mass spectrometry for the F2 isoprostanes iPF2alpha-III and iPF2alpha-VI and arachidonic acid (AA). Urinary excretion of the 2 F2 isoprostanes was significantly increased in hypercholesterolemic patients, whereas substrate AA in urine did not differ between the groups. iPF2alpha-III (pmol/mmol creatinine) was elevated (P<0.0005) in homozygous familial hypercholesterolemic (HFH) patients (85+/-5. 5; n=38) compared with age- and sex-matched normocholesterolemic control subjects (58+/-4.2; n=38), as were levels of iPF2alpha-VI (281+/-22 versus 175+/-13; P<0.0005). Serum cholesterol correlated with urinary iPF2alpha-III (r=0.41; P<0.02) and iPF2alpha-VI (r=0. 39; P<0.03) in HFH patients. Urinary excretion of iPF2alpha-III (81+/-10 versus 59+/-4; P<0.05) and iPF2alpha-VI (195+/-18 versus 149+/-20; P<0.05) was also increased in moderately hypercholesterolemic subjects (n=24) compared with their controls. Urinary excretion of iPF2alpha-III and iPF2alpha-VI was correlated (r=0.57; P<0.0001; n=106). LDL iPF2alpha-III levels (ng/mg arachidonate) were elevated (P<0.01) in HFH patients (0.32+/-0.08) compared with controls (0.09+/-0.02). The concentrations of iPF2-III in LDL and urine were significantly correlated (r=0.42; P<0.05) in HFH patients. CONCLUSIONS: Asymptomatic patients with moderate and severe hypercholesterolemia have evidence of oxidant stress in vivo.     

Effect of oral calcium loading on intact PTH and calcitriol in idiopathic renal calcium stone formers and healthy controls

The calciuric response after an oral calcium load (1000 mg elemental calcium together with a standard breakfast) was studied in 13 healthy male controls and 21 recurrent idiopathic renal calcium stone formers, 12 with hypercalciuria (UCa x V > 7.50 mmol/24 h) and nine with normocalciuria. In controls, serum 1,25(OH)2 vitamin D3 (calcitriol) remained unchanged 6 h after oral calcium load (50.6 +/- 5.1 versus 50.9 +/- 5.0 pg/ml), whereas it tended to increase in hypercalciuric (from 53.6 +/- 3.2 to 60.6 +/- 5.4 pg/ml, P = 0.182) and fell in normocalciuric stone formers (from 45.9 +/- 2.6 to 38.1 +/- 3.3 pg/ml, P = 0.011). The total amount of urinary calcium excreted after OCL was 2.50 +/- 0.20 mmol in controls, 2.27 +/- 0.27 mmol in normocalciuric and 3.62 +/- 0.32 mmol in hypercalciuric stone formers (P = 0.005 versus controls and normocalciuric stone formers respectively); it positively correlated with serum calcitriol 6 h after calcium load (r = 0.392, P = 0.024). Maximum increase in urinary calcium excretion rate, delta Ca-Emax, was inversely related to intact PTH levels in the first 4 h after calcium load, i.e. more pronounced PTH suppression predicted a steeper increase in urinary calcium excretion rate. Twenty-four-hour urine calcium excretion rate was inversely related to the ratio of delta calcitriol/deltaPTHmax after calcium load (r = -0.653, P = 0.0001), indicating that an abnormally up-regulated synthesis of calcitriol and consecutive relative PTH suppression induce hypercalciuria.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased urinary hyaluronic acid and interstitial cystitis

PURPOSE: We compared urinary levels of hyaluronic acid in patients who met the National Institute for Diabetes, and Digestive and Kidney Diseases criteria for interstitial cystitis and in age matched healthy female controls. MATERIALS AND METHODS: Urinary hyaluronic acid was measured by solid phase radiometric assay using hyaluronic acid binding protein. Hyaluronic acid and symptom scores were compared in interstitial cystitis patients who gave multiple urine samples during treatment. Since hyaluronic acid changed with treatment in some patients, 17 samples from untreated interstitial cystitis patients were selected and compared with 17 control samples. RESULTS: Mean plus or minus standard deviation urinary hyaluronic acid concentrations were similar in the 2 groups (interstitial cystitis group 574 +/- 496, controls 512 +/- 324 ng./ml., p = 0.77). When normalized to creatinine urinary hyaluronic acid was significantly higher in interstitial cystitis patients (interstitial cystitis group 674 +/- 220, controls 446 +/- 220 ng./mg. creatinine, p = 0.0019). Urinary creatinine concentrations did not differ significantly (interstitial cystitis group 842 +/- 715, controls 1,162 +/- 516 mg./l., p = 0.12). CONCLUSIONS: Urinary hyaluronic acid was higher in interstitial cystitis patients than healthy controls. Since bladder hyaluronic acid is below the epithelium, this finding may indicate leakage across the epithelium into the urine in interstitial cystitis patients.     

Circulating levels of interleukin-6 and tumor necrosis factor-alpha are elevated in primary hyperparathyroidism and correlate with markers of bone resorption--a clinical research center study

The pathogenesis of PTH-induced bone loss is uncertain. Experimental evidence suggests that PTH induces the production by osteoblasts of the bone-resorbing cytokine, interleukin-6. We measured the circulating levels of interleukin-6, tumor necrosis factor-alpha, and interleukin-1 beta and examined their relationship to biochemical markers of bone turnover in 38 patients with primary hyperparathyroidism (7 of whom also were studied after successful parathyroid adenomectomy), 6 patients with hypoparathyroidism, and 12 subjects with normal parathyroid function. The patients with untreated primary hyperparathyroidism had mean serum levels of interleukin-6 that were 16-fold higher than control values (mean +/- SEM; primary hyperparathyroidism 18.6 +/- 2.1 pg/mL, controls 1.1 +/- 0.1; P < 0.001). Circulating levels of interleukin-6 soluble receptor (primary hyperparathyroidism 41.7 +/- 1.2 ng/ mL, controls 25.1 +/- 1.0; P < 0.001), and tumor necrosis factor-alpha (primary hyperparathyroidism 11.6 +/- 0.8 pg/mL, controls 2.5 +/- 0.2; P < 0.001) were also elevated. After successful parathyroid adenomectomy, levels of each of these cytokines fell into the normal range. The mean levels of interleukin-6, its soluble receptor, and tumor necrosis factor-alpha in the subjects with hypoparathyroidism were lower than control values (P < 0.001 for each variable). There was no difference between subjects with primary hyperparathyroidism and controls in the circulating level of interleukin-1 beta. In the subjects with untreated primary hyperparathyroidism, serum levels of interleukin-6 correlated strongly with those of intact PTH (r = 0.47, P = 0.003) and biochemical markers of bone resorption: serum deoxypyridinoline (r = 0.93, P < 0.001), serum type I collagen carboxyterminal telopeptide (r = 0.87, P < 0.001), urinary pyridinoline (r = 0.81, P < 0.001), and urinary deoxypyridinoline (r = 0.63, P = 0.005). Levels of tumor necrosis factor-alpha correlated less strongly with the same variables: PTH (r = 0.41, P = 0.01), serum deoxypyridinoline (r = 0.48, P = 0.002), serum type I collagen carboxyterminal telopeptide (r = 0.46, P = 0.004), urinary pyridinoline (r = 0.61, P = 0.008), and urinary deoxypyridinoline (r = 0.61, P = 0.007). Levels of interleukin-6 also correlated with those of tumor necrosis factor-alpha (r = 0.44, P = 0.005). Multiple regression analysis indicated that interleukin-6, but not tumor necrosis factor-alpha, was independently predictive of bone resorption. We conclude that serum levels of interleukin-6 and tumor necrosis factor-alpha are increased in patients with primary hyperparathyroidism and are normalized by successful surgical treatment. The finding that these cytokines correlate with biochemical markers of bone resorption suggests that they play a role in the pathogenesis of bone loss in primary hyperparathyroidism.     

Biological monitoring of environmental exposure to PAHs in the vicinity of a S?derberg aluminium reduction plant

OBJECTIVES: To assess environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in the vicinity of a S?derberg aluminium reduction plant in Shawinigan, Canada with urinary 1-hydroxypyrene (1-OHP) as a biomarker. METHODS: Urine samples were collected from 20 non-occupationally exposed subjects living less than 500 m from the plant and from 20 controls living in Trois-Rivières, another industrial town 40 km from Shawinigan. Concentrations of 1-OHP were measured by high performance liquid chromatography (HPLC). RESULTS: Among controls, geometric mean (range) 1-OHP concentrations were 0.046 (0.012-0.116) mumol/mol creatinine in non-smokers and 0.125 (0.051-0.282) mumol/mol creatinine in smokers. Among exposed subjects, values were 0.103 (0.056-0.196) mumol/mol creatinine in non-smokers and 0.250 (0.112-0.448) mumol/mol creatinine in smokers. Excretion of 1-OHP was significantly higher in exposed subjects than in controls among non-smokers and smokers (P < 0.05). CONCLUSION: Based on urinary 1-OHP as a biomarker, it seems that living near an industrial point source of PAHs is associated with higher exposure. The health significance of this finding will require further investigation.     

Tumors of the oral cavity, oropharynx and salivary glands. Role of TC and MRI in neoplasm staging

The 32P-postlabelling assay is one of the most sensitive methods for detection of DNA adducts induced by exposure to genotoxic chemicals. Under optimal conditions, detection limits of one adduct per 10(9)-10(10) nucleotides have been reported. This sensitivity now allows monitoring of occupational and even environmental exposure of humans to certain classes of chemicals, mainly polycyclic aromatic hydrocarbons (PAH). Despite its widespread use, 3P-postlabelling is still not a standardized method. Rigorous interlaboratory comparisons are scarce, and those that have been undertaken often show rather different results, both in relative and in absolute values, for the amounts of DNA adducts in the same samples. Furthermore, the optimization of many steps in the procedure has still not been given adequate attention. This paper deals with some technical aspects of detection of PAH-DNA adducts by 32P-postlabelling, in particular with assay calibration and adduct quantification. For this purpose, benzo[a]pyrene (BP)-modified DNA standards were prepared, the adduct contents of which were determined by use of an independent fluorometric method, viz. synchronous fluorescence spectrophotometry (SFS). These BP-DNA standards are processed along with the test samples throughout the entire 32P-postlabelling procedure, from the enzymic digestion up to and including the determination of radioactivity in adduct spots on the chromatogram. As such, these reference samples can be considered as external standards for inter-assay calibration. This method for adduct quantification was compared with the commonly used relative adduct labelling (RAL) and comparative dAMP labelling, which appeared to give rise to an underestimation of adduct levels. The method was applied in a biomonitoring study among workers in a carbon-electrode manufacturing plant, exposed to PAH. Although DNA adduct levels in peripheral blood lymphocytes of exposed workers, as determined by 32P-postlabelling, were not significantly different from those of controls, a significant difference was seen when smokers and non-smokers were compared.     

Urinary N-acetyl-beta-glucosaminidase as an indicator of renal dysfunction in electroplating workers

OBJECTIVES: To investigate chromium-induced renal dysfunction in electroplating workers. METHODS: A cross-sectional study was used to evaluate four biochemical markers of renal function. A total of 178 workers were divided into 3 comparable groups consisting of 34 hard-chrome plating workers, 98 nickel-chrome electroplating workers. and 46 aluminum anode-oxidation workers, who represented the reference group. Ambient and biological monitoring of urinary chromium were performed to measure exposure concentrations. RESULTS: Overall, urinary chromium concentrations were highest among hard-chrome plating workers (geometric mean 2.44 microg/g creatinine), followed by nickel-chrome electroplating workers (0.31 microg/g creatinine) and aluminum workers (0.09 microg/g creatinine). Airborne chromium concentrations were also highest in the hard-chrome plating area (geometric mean 4.20 microg/m3), followed by the nickel-chrome electroplating area (0.58 microg/m3) and the aluminum area (0.43 microg/m3). A positive correlation was found between urinary chromium and airborne concentrations (r=0.54, P < 0.01). Urinary concentrations of N-acetyl-beta-D-glucosaminidase (NAG) were also highest among hard-chrome plating workers (geometric mean 4.9 IU/g creatinine), followed by nickel-chrome workers (3.4 IU/g creatinine) and aluminum workers (2.9 IU/g creatinine). The prevalence of "elevated" NAG (>7 IU/g creatinine) was significantly highest among hard-chrome plating workers (23.5%), then among nickel-chrome workers (7.1%) and aluminum workers (8.7%). Differences in beta2-microglobulin, total protein, and microalbumin were not significant. CONCLUSION: The author's evidence indicates that NAG is an early indicator of renal dysfunction in hard-chrome plating workers.     

8-epi PGF2 alpha generation during coronary reperfusion. A potential quantitative marker of oxidant stress in vivo

BACKGROUND: Myocardial reperfusion is believed to be associated with free radical injury. However, indexes of oxidative stress in vivo have been limited by their poor specificity and sensitivity. Isoprostanes are stable products of arachidonic acid formed in a nonenzymatic, free radical-catalyzed manner. We have developed a sensitive and specific assay for one of these compounds, 8-epi prostaglandin (PG) F2 alpha. METHODS AND RESULTS: To address its utility as an index of oxidative stress during coronary reperfusion, we measured urinary levels by gas chromatography/mass spectrometry in a canine model of coronary thrombolysis, in patients with acute myocardial infarction treated with thrombolytic therapy, and in patients after elective coronary artery bypass surgery. Urinary 8-epi PGF2 alpha was unchanged after circumflex artery occlusion in a canine model of coronary thrombolysis (n = 13; 437.2 +/- 56.4 versus 432.7 +/- 55.2 pmol/mmol creatinine) but increased significantly (P < .05) immediately after reperfusion (553.8 +/- 64.7 pmol/mmol). Urinary levels were increased (P < .001) in patients (n = 12) with acute myocardial infarction given lytic therapy (265.8 +/- 40.8 pmol/mmol) compared with age-matched control subjects (n = 20; 91.5 +/- 11.8 pmol/mmol) and patients with stable coronary disease (n = 20; 95.7 +/- 6.3 pmol/mmol). Preoperative levels rose from 113.2 +/- 11.8 to 248.2 +/- 86.3 pmol/mmol at 30 minutes into revascularization to 332.2 +/- 82.6 pmol/mmol by 15 minutes after global myocardial reperfusion (P < .05) and dropped to 181.2 +/- 50.4 pmol/mmol at 30 minutes and 120.2 +/- 9.9 pmol/mmol at 24 hours after bypass surgery (n = 5). Corresponding changes in spin adduct formation, found with electron paramagnetic resonance, were noted in 2 patients. CONCLUSIONS: These data support the hypothesis that free radical generation occurs during myocardial reperfusion. Measurement of isoprostane production may serve as a noninvasive index of oxidative stress.