Acetyl coenzyme A kinetic studies on N-acetylation of environmental carcinogens by human N-acetyltransferase 1 and its NAT1*14B variant

N-acetyltransferase 1 (NAT1) is a xenobiotic metabolizing enzyme that uses acetyl coenzyme A (AcCoA) as a cofactor for N-acetylation of many carcinogens including aromatic amines and alkylanilines. NAT1 is characterized by single nucleotide polymorphisms (SNPs) that may modulate affinity towards AcCoA. In the current study, we used Chinese hamster ovary (CHO) cells stably transfected with human NAT1*4 (reference allele) or NAT1*14B (variant allele) to measure AcCoA kinetic parameters for N-acetyltransferase activity measurements towards p-aminobenzoic acid (PABA), 4-aminobiphenyl (4-ABP), β-naphthylamine (BNA), benzidine and 3,4-dimethylaniline (3,4-DMA). Our results showed higher N-acetylation rates for each substrate catalyzed by NAT1*4 compared to NAT1*14B. NAT1*4 exhibited higher affinity to AcCoA when catalyzing the N-acetylation of BNA and benzidine compared to NAT1*14B. The results of the current study provide further insights into differences in carcinogen metabolism among individuals possessing the NAT1*14B haplotype.

Intake of milk and other dairy products and the risk of bladder cancer: a pooled analysis of 13 cohort studies

BACKGROUND

Inconsistent associations between milk and other dairy product consumption and bladder cancer (BC) have been reported. We aimed to investigate possible associations with BC risk for total and individual dairy products by bringing together the world's data on this topic.

METHODS

Thirteen cohort studies, included in the BLadder cancer Epidemiology and Nutritional Determinants (BLEND) study, provided data for 3590 BC cases and 593,637 non-cases. Associations between milk and other dairy product consumption and BC risk were investigated using Cox proportional hazard regression analyses stratified by study center and adjusted for potential confounders.

RESULTS

Overall, total 'other' dairy product consumption was not associated with BC risk (HR comparing highest with lowest tertile: 0.97 (95% CI: 0.87-1.07; p_trend = 0.52) and likewise no association was observed for either liquid milk, processed milk, cream, cheese or icecream. However, an inverse association was observed between yoghurt consumption and BC risk when comparing those in the moderate (25-85 g/day) and high categories (>85 g/day) with non-consumers, with multivariate HR of 0.85 (95% CI: 0.75-0.96) and 0.88 (95% CI: 0.78-0.98), respectively.

CONCLUSIONS

We found no evidence of association between either total or individual dairy products and BC risk, but suggestive evidence that consumption of yoghurt may be associated with a decreased risk.

Safety and efficacy of methenamine hippurate for the prevention of recurrent urinary tract infections in adult renal transplant recipients: A single center, retrospective study

BACKGROUND

Recurrent urinary tract infections (UTI) are an important cause of morbidity and mortality in renal transplant recipients (RTR).

METHODS

In this retrospective study we gathered clinical data from patients prescribed methenamine hippurate to prevent recurrent UTI pre- and post-intervention. Thirty-eight RTR ≥18 years old at Northwestern Memorial Hospital from 2006-2017 were included in the final analysis.

RESULTS

The median and range for follow-up days were 365 (299-365) pre- vs 314 (105-365) post-methenamine. Total UTI frequency (9.16 vs 5.01/1000 patient follow-up days), days of antibiotic therapy to treat UTI (215 vs 132/1000 patient follow-up days), and hospitalization due to UTI (2.64 vs 1.07/1000 patient follow-up days) decreased while patients took methenamine. Escherichia coli and Klebsiella pneumoniae were the most commonly identified cause of UTI both pre- and post-intervention. Drug resistant bacteria (ESBL-producing or VRE) affected 3 patients pre- and recurred in 1 of those patients plus 3 new patients post-methenamine. Methenamine had few adverse side effects for patients. One patient had nausea and 1 was intolerant.

CONCLUSION

We found that methenamine is well tolerated and is useful in reducing UTI, antibiotic prescriptions, and hospitalization in RTR with recurrent UTI. Larger prospective studies are needed to confirm these findings.

Defining the Pathways of Urogenital Schistosomiasis-Associated Urothelial Carcinogenesis through Transgenic and Bladder Wall Egg Injection Models

Urogenital schistosomiasis (infection with Schistosoma haematobium) is a major cause of bladder carcinogenesis. However, the exact mechanisms of the sequelae leading up to the development of bladder cancer are poorly understood, mainly because of a dearth of tractable mouse models. We developed a mouse model of urogenital schistosomiasis through intramural injection of parasite eggs into the bladder wall to mimic the trapping of parasite eggs in the bladder. This approach recapitulates many of the sequelae observed in infected humans. Here, we describe procedures for utilizing this surgical technique in combination with well-established transgenic mouse strains to dissect the role of cancer-related genes in the initiation and establishment of bladder carcinogenesis. The described method utilizes CRE-mediated flox activity to render mice p53 haploinsufficient before challenging them with bladder wall egg injection. These techniques are potentially amenable to studying the role of other pro-carcinogenic and cancer suppressor gene(s) in urogenital schistosomiasis-associated urothelial carcinogenesis.

Molecular markers and Schistosoma-associated bladder carcinoma: A systematic review and meta-analysis

BACKGROUND

Molecular mechanisms and pathogenesis of schistosomal-associated bladder cancer (SABC), one of the most common malignancies in Africa and parts of the Middle East, is still unclear. Identification of host molecular markers involved in schistosomal related bladder carcinogenesis is of value in prediction of high-risk group, early detection and timely intervention.

METHODS

PubMed, Scopus, Google Scholar, Cochrane Library and African Journals Online databases were systematically searched and reviewed. A total of 63 articles reporting 41 host molecular factors were included in the meta-analysis.

RESULTS

Pooled odds ratio demonstrated associations of p53 expression, telomerase activity and sFas with SABC as compared to other schistosomal patients (p53 expression: OR=9.46, 95%CI=1.14-78.55, p=0.04; telomerase by TERT: OR=37.38, 95%CI=4.17-334.85, p=0.001; telomerase by TRAP: OR=10.36, 95%CI=6.08-17.64, p<0.00001; sFas: OR=34.37, 95%CI=3.32-355.51, p=0.003). In comparison to bladder cancers of other etiology, positive associations were found between SABC and p15 deletion, p16 deletion, telomerase activity and sFas (p15 deletion: OR=4.20, 95%CI=2.58-6.82, p<0.00001; p16 deletion: OR=4.93, 95%CI=2.52-9.65, p<0.00001; telomerase by TERT: OR=3.01, 95%CI=1.51-5.97, p=0.002; telomerase by TRAP: OR=2.66, 95%CI=1.18-6.01, p=0.02; sFas: OR=4.50, 95%CI=1.78-11.40, p=0.001). Other identified associations were reported by few numbers of studies to enable reliable interpretation.

CONCLUSIONS

Variations in gene expression or genomic alterations of some molecular markers in SABC as compared to non-SABC or other schistosomal patients were identified. These suggest minute differences in the pathogenesis and physiological profile of SABC, in relation to non-SABC.