Biological fate of styrene oxide adducts with globin: Elimination of cleavage products in the rat urine.

The in vivo fate of globin adducts with styrene 7,8-oxide (SO), an electrophilic metabolic intermediate of styrene, was studied in male Wistar rats dosed intraperitoneally with racemic SO, 100mg/kg b.w. Regioisomeric hydroxy(phenyl)ethyl (HPE) adducts at Cys, N-terminal Val, Lys and His in globin were determined and their elimination from blood was followed during 60days, corresponding to life span of rat erythrocytes. In the rat urine, Nα-acetylated products of hydrolytic cleavage of the HPE adducts with Cys, Lys and His were determined. On the first day post-exposure, abundant Nα-acetyl-HPE-Cys adducts (mercapturic acids) formed via direct conjugation of SO with hepatic glutathione were excreted rapidly, but then a much slower phase of elimination reflecting formation of Nα-acetyl-HPE-Cys via cleavage of the adducted globin was observed. A two-phase elimination occurred also in urinary Nα-acetyl-HPE adducts with His and Lys. While a decline by 75-85% during the first 7days post-exposure most likely reflected elimination of adducted albumin, the subsequent slow decline until day 60 corresponded to elimination kinetics of the adducted globin. Thus, the study not only provided original data on the fate of SO-globin adducts but also allowed to reveal general toxicokinetics properties of the urinary cleavage products as a novel type of chemical exposure biomarkers.

Hydrolytic Cleavage Products of Globin Adducts in Urine as Possible Biomarkers of Cumulative Dose: Proof of Concept Using Styrene Oxide as a Model Adduct-Forming Compound.

A new experimental model was designed to study the fate of globin adducts with styrene 7,8-oxide (SO), a metabolic intermediate of styrene and a model electrophilic compound. Rat erythrocytes were incubated with SO at 7 or 22 °C. Levels of specific amino acid adducts in globin were determined by LC/MS analysis of the globin hydrolysate, and erythrocytes with known adduct content were administered intravenously to recipient rats. The course of adduct elimination from the rat blood was measured over the following 50 days. In the erythrocytes incubated at 22 °C, a rapid decline in the adduct levels on the first day post-transfusion followed by a slow phase of elimination was observed. In contrast, the adduct elimination in erythrocytes incubated at 7 °C was nearly linear, copying elimination of intact erythrocytes. In the urine of recipient rats, regioisomeric SO adducts at cysteine, valine, lysine, and histidine in the form of amino acid adducts and/or their acetylated metabolites as well as SO-dipeptide adducts were identified by LC/MS supported by synthesized reference standards. S-(2-Hydroxy-1-phenylethyl)cysteine and S-(2-hydroxy-2-phenylethyl)cysteine, the most abundant globin adducts, were excreted predominantly in the form of the corresponding urinary mercapturic acids (HPEMAs). Massive elimination of HPEMAs via urine occurred within the first day from the erythrocytes incubated at both 7 and 22 °C. However, erythrocytes incubated at 7 °C also showed a slow second phase of elimination such that HPEMAs were detected in urine up to 50 days post-transfusion. These results indicate for the first time that globin adducts can be cleaved in vivo to modified amino acids and dipeptides. The cleavage products and/or their predictable metabolites are excreted in urine over the whole life span of erythrocytes. Some of the urinary adducts may represent a new type of noninvasive biomarker for exposure to adduct-forming chemicals.

Urine versus brushed samples in human papillomavirus screening: study in both genders.

AIM: To investigate whether urine is a good medium for screening and whether there is a correlation between the amount of extracted DNA and human papillomavirus (HPV)-positivity. METHODS: In the present study, 30 first-voided urine (FVU) specimens and 20 urethroglandular swabs using cervex-brushes from male partners of HPV-positive patients, and 31 FVU specimens and 100 liquid-based cervix cytology leftovers sampled with cervix-brushes from HPV-positive women were examined for the presence of beta-globin. Oncogenic HPV were detected using type-specific PCR. RESULTS: beta-globin was found in all the brushed samples, whereas it was found in only 68.9% of the FVU specimens. HPV-PCR was positive in 60.0% of the male brushes, in 29% of the female brushes and in 0% of the male FVU specimens. DNA concentration was, respectively, 0.9998 ng/microL, 37.0598 ng/microL and 0.0207 ng/microL. CONCLUSION: Urine is not a good tool for HPV detection, probably because the low DNA concentration reflects a low amount of collected cells. beta-globin is measurable in FVU by real time quantitative PCR, but the DNA concentration is lower compared to brush sampling for both genders. beta-globin-positivity of urethral and cervical swabs is 100%, showing a higher mean concentration of DNA, leading to a higher detection rate of HPV. This is the first article linking DNA-concentration to the presence of HPV.

Absence of increased alpha1-microglobulin in IgA nephropathy proteinuria.

To search for biomarkers of IgA nephropathy, protein profiles of urine samples from patients with IgA nephropathy and normal volunteers were compared using two-dimensional DIGE. Most of the 172 spots identified in the urine were serum proteins, and their amounts in IgA nephropathy urine were much higher than those in normal urine; this can be explained as proteinuria caused by glomerular dysfunction. However, only alpha(1)-microglobulin, also one of the major serum proteins, in IgA nephropathy urine was not higher in amount than that in normal urine. We confirmed using ELISA analysis that the amounts of transferrin and albumin in IgA nephropathy and diabetic nephropathy urine were much higher than those in normal urine, whereas the amount of alpha(1)-microglobulin in IgA nephropathy urine was not higher than that in normal urine and was much lower than that in diabetic nephropathy urine. Approximately 50% of alpha(1)-microglobulin forms a complex with IgA in serum. These results suggest that alpha(1)-microglobulin in IgA nephropathy urine is a characteristic protein and might be a biomarker for IgA nephropathy and that alpha(1)-microglobulin might have a relationship with IgA nephropathy pathology.

[Reference intervals of urinary biochemical analysis in Japanese men].

To determine the reference intervals of urinary albumin, immunoglobulin G, transferrin, alpha 1 microglobulin, and N-acetyl-beta-D-glucosaminidase, we measured those components and creatinine in urine from men with normal blood pressure(systolic < or = 139 mmHg and diastolic < or = 89 mmHg), HbA1c < or = 5.8% and negative qualitative tests of urinary protein and hematuria. The subjects were 150 men in their thirties, 136 in their forties, and 135 in their fifties. Urines was collected in the morning after at least 12 hours fast and stored at -80 degrees C until assayed. The levels of creatinine decreased with age, whereas no change was observed in the levels of other urinary components. Consequently, the levels of those components expressed as g. creatinine increased with age. The reference intervals per g. creatinine were determined for each age-bracket using the iterative truncation method after logarithmical transformation of the values.

High prevalence of human papillomavirus infection in Mexican males: comparative study of penile-urethral swabs and urine samples.

BACKGROUND: Although extensive information has been gathered about the prevalence and determinants of human papillomavirus infection among women, little is known about the prevalence and natural history of this infection among males. GOAL: To investigate the potential usefulness of urine specimens to assess the presence of genital human papillomavirus DNA infection. STUDY DESIGN: The authors conducted a study of 120 healthy men from Cuernavaca, Mexico. A urine specimen and urethral and coronal sulcus swab samples were collected and tested for human papillomavirus using the GP5+/6+ polymerase chain reaction enzyme immunoassay method. RESULTS: In 95% of the urethral-coronal sulcus samples, the beta-globin gene was detectable, indicating adequacy of the specimen for DNA amplification; however, only 14% of the urine specimens had detectable beta-globin. Removal of inhibitors by DNA purification in a sample of subjects produced beta-globin amplification, but no increase in human papillomavirus DNA positivity was detected. Human papillomavirus DNA was not detectable in penile-urethral swab samples in any of the subjects who reported not having engaged in sexual activity but was present in 43% of men who reported sexual activity, a strong indication of the sexual transmission of human papillomavirus. CONCLUSIONS: Human papillomavirus is a common sexually transmitted infection among Mexican males, and urine sample specimens cannot adequately detect the presence of this infection in males.