Malignancies of the urinary tract and their relation to analgesic abuse

Cancer in Patients on CAPD

Many workers have reported a high incidence of cancer in persons with uremia or on hemodialysis but there is no agreement on this point. Because the incidence of neoplasms in patients on CAPD is unknown, we reviewed the medical records of the 328 patients treated with CAPD at the TWH from 1977 to 1985. Of these, nine developed cancers, of whom three had been treated with immunosuppressive agents previously. Whether or not these three patients are included, we found no significant difference in cancer incidence between the CAPD and the control population (p = 0.12 and 0.51 respectively). In conclusion, this review found no evidence that our CAPD patients had an increased incidence of cancer.

Although an increased incidence of cancer has been reported in patients with chronic renal failure, before or while on hemodialysis, there is no agreement on the issue. The reported incidence of tumors in different studies ranged widely between 0.84 and 9.5% (I, 2). Even though an increasing number of patients have been treated on CAPD, the literature contains no information regarding the incidence of cancer in this population. The present study was undertaken to provide an answer to this question.

Chemical-Induced Nephropathy: A Review of the Renal Tubulointerstitial Lesions in Humans

It is almost ironic that one of the major organs that serves to maintain the “internal milieux” by secretion of various toxic agents, can itself become injured in the process. The pattern of morphologic renal injury is nonspecific and can involve any of the components of the kidney, although the injury and subsequent morphologic changes are most commonly noted in the tubules and/or interstitium. Of course, unless the drug/toxin is commonly or regularly noted to be associated with tubular and/or interstitial injury, the association of the drug with the renal changes may be missed and the correlation may not necessarily identify causation. For example, if a drug is associated with a renal injury in a given individual, it may be quite difficult to prove that the drug is the cause of the injury. This scenario is somewhat reminiscent of the test question—is it “true-true-related,” or “true-true-unrelated”? Sometimes it is only by the accrual of a great many examples or correlations, and or dissection of the pathophysiology, can it be shown that the drug is directly related to the observed morphologic (and subsequent clinical) injury. Renal changes induced by chemicals can affect the tubules, interstitium or both. This review of chemically induced nephropathy in humans considers acute tubular necrosis, interstitial nephritis , and tubulointerstitial nephritis or nephropathy. Because the tubules and the interstitium are so intimately related, injury to 1 of these 2 components may eventually lead to injury of the other, resulting in tubulointerstitial disease.

Onco-nephrology: an appraisal of the cancer and chronic kidney disease links

A bidirectional relationship has been observed for kidney disease and cancer. On the one hand, cancer is an important complication noted in kidney disease as well as a major cause of morbidity and mortality in this group. On the other hand, improved cancer treatment has prolonged survival, but also increased the development of acute and chronic kidney disease. The combination of cancer and kidney disease makes it challenging for clinicians to provide comprehensive and safe therapies for this group of patients. As such, clinicians caring for this group must develop expertise and become competent in the practice of a newly evolving subspecialty of nephrology known as 'onco-nephrology'. This brief narrative review will focus on the cancer risk in patients with underlying kidney disease, the therapies such as erythropoiesis-stimulating agents on cancer progression and other outcomes, and the appropriate dosing of anti-cancer agents in patients with underlying kidney disease.

Reduction of aromatic and heterocyclic aromatic N-hydroxylamines by human cytochrome P450 2S1

Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals, and there is also strong evidence of some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anticancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions [Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740-1751]. In the study presented here, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs.

Cancer-specific mortality in chronic kidney disease: longitudinal follow-up of a large cohort

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is known to be associated with increased all-cause and cardiovascular mortality, but no large studies examined the cancer-specific mortality in non-dialysis-dependent CKD patients. Such outcome data are needed for proper allocation of resources and would help to develop better preventive services.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between 1998 and 1999, 123,717 adults were recruited from four health screening centers in Taiwan. The estimated glomerular filtration rate was calculated using the four-variable Modification of Diet in Renal Disease Study equation for the Chinese. Mortality was ascertained by computer linkage to the national death registry after a median follow-up of 7.06 years. Cox proportional hazards regression models were used to estimate the impact of CKD on cancer-specific mortality.

RESULTS

A higher risk for overall cancer mortality was found in CKD patients compared with non-CKD patients (adjusted hazard ratio, 1.2). CKD was associated with increased mortality from liver cancer, kidney cancer, and urinary tract cancer, with an adjusted hazard ratio of 1.74, 3.3, and 7.3, respectively. A graded relationship between the severity of renal impairment and cancer mortality was also found.

CONCLUSIONS

Patients with CKD had a higher mortality risk of liver cancer, kidney cancer, and urinary tract cancer. This is the first large study that showed an inverse association between renal function and liver cancer mortality. The increased mortality could be caused by higher cancer incidence or worse response to cancer treatment. Future research is warranted to clarify the mechanism.

Evaluating human liver reserve function by measuring serum concentrations of phenacetin and its metabolites

OBJECTIVES

To evaluate human liver reserve function (LRF) by a simple and efficient method for measuring serum concentrations of phenacetin and its metabolites.

METHODS

Overall 20 patients with liver cirrhosis (Child-Pugh score ≥ 7, aged 48-79 years), 30 healthy young volunteers (aged 18-40 years), and 20 healthy elderly volunteers (aged 61-80 years) were enrolled. All participants received a single oral dose of 0.5 g phenacetin. Liquid chromatography tandem mass spectrometry was used to determine the serum concentrations of phenacetin and its metabolites, including acetaminophen, acetaminophen glucuronide and acetaminophen sulfate.

RESULTS

The serum concentration of phenacetin was significantly higher in cirrhotic patients than those in either of the healthy volunteer groups (P < 0.001). It was higher in healthy elderly volunteers than that in healthy young ones but there was no statistically significant difference (P > 0.05) between them. The serum concentrations of acetaminophen, acetaminophen glucuronide and acetaminophen sulfate were significantly lower in cirrhotic patients than in the healthy controls (P < 0.001). The serum concentrations of these three metabolites in healthy elderly volunteers were lower than those in healthy younger volunteers but again, there was no statistical significant difference (P > 0.05). The serum concentration of acetaminophen in healthy male volunteers was significantly higher than that in the women (P < 0.05).

CONCLUSION

Monitoring cytochrome P450 1A2 (CYP450 1A2)-mediated phenacetin metabolism is a simple and efficient method for evaluating human LRF. This method would warrant further validation in a large cohort clinical study.

Analgesic nephropathy and renal replacement therapy in Australia: trends, comorbidities and outcomes

BACKGROUND AND OBJECTIVES

This study examined age-specific incidence and prevalence of renal replacement therapy attributed to analgesic nephropathy from 1971 through 2005 and adjusted comorbidity prevalence and survival of patients who had analgesic nephropathy and were on renal replacement therapy (compared with control subjects without diabetes).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study, using data from the Australia and New Zealand Dialysis and Transplant registry, included all patients who were aged 35 to 84 yr and started long-term renal replacement therapy in Australia from 1971 through 2006.

RESULTS

Of 31,654 incident renal replacement therapy patients, 10.2% had analgesic nephropathy. Incidence and prevalence of renal replacement therapy attributed to analgesic nephropathy decreased earlier and faster among younger (age <55 yr) patients. Prevalence of analgesic nephropathy among 75- to 84-yr-old renal replacement therapy patients is still increasing. Compared with control subjects without diabetes, comorbidities (coronary artery, cerebrovascular, peripheral vascular, and chronic lung diseases) were more prevalent among patients with analgesic nephropathy at renal replacement therapy start. All-cause, cardiovascular, infection, and cancer mortality were higher among patients who had analgesic nephropathy and were on renal replacement therapy. For both comorbidities and mortality, the associations were stronger in younger patients.

CONCLUSIONS

Trends in renal replacement therapy attributed to analgesic nephropathy differed by age. Patients with analgesic nephropathy have more comorbidities and poorer survival on renal replacement therapy, especially among younger patients.

Renal papillary necrosis

Renal papillary necrosis (RPN) is a significant problem in human beings, especially in England and in Australia where it has been reported to account for 15% to 20% of patients needing renal transplants. Many compounds, including aspirin, phenacetin, phenylbutazone, indomethacin, mefenamic acid, flufenamic acid, fenoprofin, naproxen, and ibuprofen have been linked to renal papillary necrosis in human beings. Although the exact mechanism of RPN is unknown, there are several theories that have good scientific evidence behind them. Study of RPN in animals as models for the disease in human beings is limited by several factors, including anatomical differences between human beings and most animal species as well as technical difficulties in studying the renal papilla.

Nephrotoxicity of nonsteroidal anti-inflammatory drugs: physiologic foundations and clinical implications

Although the prevalence of nephrotoxicity in patients treated with nonsteroidal anti-inflammatory drugs (NSAIDs) is relatively low, the extensive use profile of these agents implies that many persons are at risk. At basal states of normal renal function, the role of renal prostaglandin production for maintenance of stable renal hemodynamic function is relatively limited. Nonetheless, in the clinical setting of reduced renal perfusion as seen in various forms of cardio-renal disease, dehydration, and the aging kidney, the adequacy of renal prostaglandin production mediated predominantly by cyclooxygenase-1 (COX-1) and, potentially, by COX-2 enzyme activity becomes of major significance in the activation of compensatory renal hemodynamics. Inhibition of renal prostaglandin production by the use of NSAIDs in these circumstances can potentially lead to the emergence of several distinct syndromes of disturbed renal function. These include fluid and electrolyte disorders, acute renal dysfunction, nephrotic syndrome/ interstitial nephritis, and renal papillary necrosis. In addition, by blunting the homeostatic renal effects of prostaglandins, NSAIDs can adversely influence blood pressure control, particularly during the use of angiotensin-converting enzyme (ACE) inhibitors, diuretics, and beta blockers. This is a matter of considerable public health concern, in that some 12 million US citizens are concurrently treated with NSAIDs and antihypertensive drugs. Finally, the risk of congestive heart failure is significantly increased when NSAIDs are given to patients receiving diuretic therapy who have cardiovascular risk factors. Physiologic factors, clinical presentations, diagnostic modalities, and clinical management strategies appropriate to these NSAID-induced renal syndromes are described.

Mutagenicity of p-aminophenol in E. coli WP2uvrA/pKM101 and its relevance to oxidative DNA damage

It was recently reported that p-aminophenol (p-AP) induces DNA cleavage in mouse lymphoma cells, CHO cells and human lymphoblastoid cells. The mutagenicity of p-AP has not, however, been detected by reverse mutation assays. The purpose of this study was to assess the mutagenicity of p-AP by reverse mutation assay using Escherichia coli WP2uvrA/pKM101, which has a spectrum for detecting mutations different from those of other strains in the family with an AT base pair at the mutation site and has higher sensitivity to certain oxidative mutagens as compared to other strains. We found that p-AP was mutagenic to E. coli WP2uvrA/pKM101. The mutagenic activity of this compound was suppressed with the addition of dimethylsulfoxide or catalase, suggesting the involvement of active oxygen species in the mutagenic process induced by p-AP. To further elucidate the underlying mechanism, we used isolated DNA for the following experiments. It was revealed, by gel electrophoretic analysis, that p-AP induced DNA cleavage in the presence of Fe(III). However, p-AP alone did not induce this cleavage. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine by p-AP in calf thymus DNA was also detected in the presence of Fe(III) by HPLC with an electrochemical detector. ESR-spin trapping experiments using DMPO detected the production of hydroxyl radical (.OH) in the solution of p-AP with Fe(III). Both p-AP mediated DNA damages and .OH production by p-AP in the presence of Fe(III) were completely inhibited by .OH scavengers (ethanol, mannitol, sodium formate, dimethylsulfoxide) and catalase. These results suggest that .OH derived from the reaction between H2O2 and Fe(III) (Fenton reaction) participates in the oxidative DNA damage. Accordingly, the same mechanism might be working in E. coli WP2uvrA/pKM101 during induction of the mutation by p-AP.

Habitual use of acetaminophen as a risk factor for chronic renal failure: a comparison with phenacetin

Six epidemiologic studies in the United States and Europe indicate that habitual use of phenacetin is associated with the development of chronic renal failure and end-stage renal disease (ESRD), with a relative risk in the range of 4 to 19. As a result of these and other studies, phenacetin has now been withdrawn from the market in most countries. However, three case control studies, one each in North Carolina, northern Maryland, and West Berlin, Germany, showed that habitual use of acetaminophen is also associated with chronic renal failure and ESRD, with a relative risk in the range of 2 to 4. These studies suggest that both phenacetin and acetaminophen may contribute to the burden of ESRD, with the risk of the latter being somewhat less than that of the former. This apparent difference in risk may not be due to differences in nephrotoxic potential of the drugs themselves. A lower relative risk would be expected for acetaminophen if the risk of both drugs in combination with other analgesics was higher than the risk of either agent alone. Thus, acetaminophen has been used both as a single agent and in combination with other analgesics, whereas phenacetin was available only in combinations. The possibility that habitual use of acetaminophen alone increases the risk of ESRD has not been clearly demonstrated, but cannot be dismissed.

High mortality from urothelial carcinoma despite regular tumor screening in patients with analgesic nephropathy after renal transplantation

Patients with end-stage renal failure due to analgesic nephropathy have an increased risk of developing a urothelial carcinoma. To determine the impact of renal transplantation on the frequency of urothelial carcinomas, we analyzed 2072 patients who underwent 2371 renal transplantation between 1968 and 1993, including 78 (3.8%) with clinically proven analgesic nephropathy. Before and after transplantation a regular tumor screening was performed in patients with analgesic nephropathy by urine cytology and abdominal sonography. In 11 of the 78 patients with analgesic nephropathy (14.1%; age 51-66 years, 40-108 months after initiation of dialysis treatment, 5-77 months after transplantation), a urothelial carcinoma of the native urinary tract, especially the kidneys, was diagnosed. Therapy comprised nephroureterectomy (n = 6), transurethral resection (n = 6) and/or cystectomy (n = 2). Seven patients died due to tumor progression 16.3 (4-33) months postoperatively and one patient died due to a perioperative complication. Despite regular tumor screening after transplantation, the diagnosis of a urothelial carcinoma was made very late, leading to a high tumor-related mortality. As a consequence, we suggest that a bilateral nephroureterectomy should be performed prophylactically in patients with proven analgesic nephropathy. In addition, a cystoscopy with lavage cytology testing of the bladder should be performed twice a year.

Effect of phenacetin pretreatment on renal pelvic carcinogenesis by N-butyl-N-(4-hydroxybutyl)nitrosamine in NON/Shi mice of both sexes

Influences of phenacetin (PH) pretreatment on renal pelvic carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) were examined in NON/Shi mice of both sexes. Histopathological examination revealed that PH pretreatment enhanced not only the induction of urinary tract carcinoma but also distant metastasis of renal pelvic carcinoma by BBN in male mice. The high incidence of urinary tract carcinoma by PH pretreatment might be due to hydronephrosis and epithelial proliferative lesions enhanced by PH, since a single treatment of PH induced hydronephrosis in all mice and simple hyperplasia in 70-80% of mice used.

Relevance of a rat model of papillary necrosis and upper urothelial carcinoma in understanding the role of ochratoxin A in Balkan endemic nephropathy and its associated carcinoma

Ochratoxin A is nephrotoxic and has been implicated in the genesis of Balkan endemic nephropathy (BEN), a condition that leads to end-stage renal disease and upper urothelial tumours. This compound induces renal parenchymal carcinoma in male mice only, and is not considered to be a potent carcinogen nor is there experimental evidence of its propensity to cause upper urothelial carcinoma. There is, however, evidence that exposure to more than one mycotoxin may be an important factor in the clinical spectrum of BEN. Analgesic nephropathy is clinically different, but is also associated with an upper urothelial carcinoma. The combination of urothelial initiation and an acute papillary necrosis in rats produces upper urothelial carcinoma. This two-stage experimental model offers the potential to assess the role of ochratoxin A in BEN-associated upper urothelial carcinoma under experimental conditions.

Increased frequency of sister-chromatid exchange and chromatid breaks in lymphocytes after treatment of human volunteers with therapeutic doses of paracetamol

Paracetamol was given to 10 healthy human volunteers in 3 doses of 1 g each during a period of 8 h. Blood samples for lymphocyte cultures were taken before and 24 h after paracetamol administration. A small but significant increase was found in the frequency of sister-chromatid exchanges (SCE) after intake of paracetamol (0.187 +/- 0.030 per chromosome before and 0.208 +/- 0.024 per chromosome after). After exposure the mean frequency of chromatid breaks per 100 cells was significantly increased (2.16 +/- 1.33 versus 0.33 +/- 0.50 before exposure). Exposure of human lymphocytes in vitro showed that concentrations of paracetamol above 0.1 mM induced inhibition of replicative DNA synthesis. Increased SCE was found in lymphocytes exposed to 1-10 mM paracetamol for 2 h. Furthermore, 0.75-1.5 mM paracetamol exposure for 24 h increased the frequency of chromatid and chromosome breaks in the lymphocytes. The paracetamol-induced SCE and chromosome aberrations may be secondary effects of paracetamol-induced inhibition of DNA synthesis or due to covalent binding of paracetamol metabolite(s) to DNA.

Morbidity of patients with analgesic-associated nephropathy on regular dialysis treatment and after renal transplantation

In a retrospective study, patients with end-stage renal failure from analgesic-associated nephropathy - 55 on regular dialysis treatment and 12 after renal transplantation - were under observation for 57 and 33 months, respectively. Of these 34 patients on chronic hemodialysis had suffered from different cardiovascular diseases. Hypertriglyceridemia was diagnosed in 62% of the patients, arterial hypertension requiring antihypertensive therapy in 44%. In three patients (5%) carcinoma of the urinary bladder were diagnosed. The leading causes of death in 21 patients included cardiovascular diseases (29%), hyperkalemia (19%), sepsis, and malignant tumors (14% each). Rejection occurred in 3 out of 12 patients after renal transplantation. Again, cardiovascular morbidity was high (58%) with coronary heart disease being present in 33% of the patients. Hypertriglyceridemia was observed in 5 out of 6 patients, antihypertensive therapy was needed in 50%. One patient died from primary pulmonary hypertension.

Epidemiology and mechanistic basis of analgesic-associated nephropathy

End-stage renal failure (ESRF) due to analgesic nephropathy is still a common clinical condition in several countries, but the prevalence in dialysis patients shows large geographical differences. The frequency of ESRF of unknown aetiology is the inverse of that linked to analgesic abuse, and data suggest that the occurrence of analgesic nephropathy may be underestimated. The study of analgesic nephropathy is difficult because the earliest damage to the kidney is a renal papillary necrosis (RPN), which cannot easily be diagnosed. Continued analgesic abuse generally leads to a progressive secondary cortical degeneration which is easier to diagnose. If analgesic abuse is stopped at an early enough stage in nephropathy, clinical symptoms stabilize or improve, and ESRF may be averted. A high incidence of upper urothelial carcinoma (UUC) is also observed in individuals with a history of analgesic abuse, but it is still not clear if the two have a related pathogenesis. Study of the mechanism of RPN in animals administered analgesics and nonsteroidal antiinflammatory drugs (NSAID) has been difficult owing to their extrarenal toxicity. Several model compounds cause identical clinical changes and have as their selective target the renal medullary interstitial cells; subsequently, other changes (including cortical and glomerular degeneration) develop as a secondary cascade. A number of mechanisms have been proposed to explain RPN (e.g., counter-current concentrating mechanism, ischaemic injury, altered prostaglandin metabolism, immunological changes), but peroxidative metabolism of papillotoxic chemicals within the interstitial cells seems to be the most likely cause. Analgesic abuse is a costly socioeconomic condition for which there is currently no clinical treatment. If it is diagnosed early enough, severe renal degeneration can be prevented. Additional epidemiological information is needed to establish the causative role of analgesics and other chemicals, in order to determine the relative risk of each. Additional animal experiments are needed in order to clarify the molecular pathogenesis of RPN and UUC, to differentiate the stages in progression to ESRF and to develop more sensitive and selective diagnostic criteria.

Genotoxicity of analgesic compounds assessed by an in vitro micronucleus assay

Several analgesic compounds and mixtures of analgesics were examined for both cytotoxicity and ability to induce chromosomal damage in the normal rat-kidney cell line NRK-49F. Chromosomal damage was assessed using an in vitro micronucleus assay. Of all the compounds tested, only N-hydroxyparacetamol caused a high degree of cell death at the concentrations used. 4 analgesic compounds were found to be inducers of micronuclei in NRK cells; in order of decreasing potency these were: N-hydroxyparacetamol, N-hydroxyphenacetin, caffeine and paracetamol. An aspirin, phenacetin, caffeine mixture (APC) failed to induce micronuclei above the background level, and a paracetamol-codeine combination did not increase the level of micronuclei induction above that induced by paracetamol alone. This report suggests paracetamol and some related compounds are capable of inducing chromosomal damage in mammalian cells in vitro, which is consistent with recent reports of a possible paracetamol-DNA interaction.

Analgesic-associated nephropathy

Although the question of whether or not analgesic abuse leads to a certain type of nephropathy has been investigated since 1953, no conclusive answer has been forthcoming. Epidemiologic investigations on the correlation between analgesic abuse and renal function as well as experimental animal studies have given contradictory results concerning the possibility of analgesic-associated kidney damage. However, studies on the correlation between analgesic abuse and papillary necrosis have demonstrated that this lesion coincides in 69% of the cases with an analgesic history. Follow-up studies of patients with analgesic nephropathy have shown that renal function deteriorates in 60% of the patients with continued abuse and that it stabilizes in 80% of the patients after cessation of abuse. Studies on the legislative restriction of phenacetin/acetaminophen, carried out mostly in Scandinavian countries since 1965, show a 50%-90% decline in signs of analgesic nephropathy (papillary necrosis) following a reduction in the sale of these drugs. The prevalence of analgesic abuse may be underestimated, since up to 80% of the abusers tend to deny their analgesic intake. Obviously, only a small percentage of analgesic abusers (approximately 1%) finally develop nephropathy. Even though the results of epidemiologic and experimental studies are contradictory, the results of investigations on papillary necrosis and on legislative prevention as well as of patient follow-ups tend to indicate a correlation between analgesic abuse and a well-defined type of nephropathy.

Inhibition of DNA, RNA and protein synthesis and chromatin alteration by N-hydroxyphenacetin

The effects of N-hydroxyphenacetin on DNA function and structure were investigated to elucidate the involvement of phenacetin in analgesic nephropathy and transitional cell carcinoma. N-Hydroxyphenacetin or a metabolite inhibited synthesis of DNA, RNA and protein; DNA inhibition was greater at higher pH. No single-strand breaks were detectable in DNA after N-hydroxyphenacetin treatment and no appreciable effect on cell viability was observed at concentrations up to 5 mM. N-Hydroxyphenacetin-induced alteration to chromatin structure was detected using nucleoid sedimentation analysis. Direct binding to plasmid DNA was not observed. These observations are consistent with a role for phenacetin metabolites in renal disease.

Phenacetin and papillary necrosis: independent risk factors for renal pelvic cancer

A case-control study was undertaken to determine whether renal papillary necrosis (RPN) is an essential step in the genesis of analgesic-associated cancer of the renal pelvis (CaP). Kidneys of 66 patients (and 86 cases of renal parenchymal cancer (CaK), for comparison) were examined for evidence of RPN. Information concerning past consumption of phenacetin-containing analgesics (PhA) was obtained from all cases and 751 population controls by means of a questionnaire. Separately, RPN and regular consumption of PhA each conferred a relative risk for CaP of 3-1/2 to 7, while together they increased the risk some 20 times that for non-consumers without RPN. This suggests that each factor has independent, and when they coexist sequential, effects. The risk for CaK was doubled by regular PhA consumption but was not increased by RPN.

Species differences in cytotoxic and genotoxic effects of phenacetin and paracetamol in primary monolayer cultures of hepatocytes

The cytotoxic and genotoxic effects of phenacetin and paracetamol were examined in monolayer cultures of hepatocytes isolated from the mouse, hamster, rat and guinea pig. No marked increase in unscheduled DNA synthesis (UDS) after exposing hepatocytes from any of the species to phenacetin was observed. At cytotoxic concentrations of paracetamol, an increased UDS in mouse hepatocytes in vitro was observed. Pretreatment of the mice by inducers of drug-metabolizing enzymes, such as 3-methylcholanthrene and Aroclor 1254, lowered the concentration threshold for the toxic responses. With rat hepatocytes only a minor increase in UDS was noted, while with hepatocytes from hamsters and guinea pigs in fact a decrease was seen. The narrow range observed between the cytotoxic and genotoxic effects of paracetamol makes it difficult to predict whether the initial DNA damage could lead to a mutation or whether the cells will die before the mutation is expressed. With respect to the cytotoxic effects, hamster hepatocytes were found to be most susceptible to paracetamol, followed by mouse, while rat and guinea pig were less affected. These data were in accordance with in vivo findings (Davis et al., 1974), indicating the potential value of hepatocyte culture when screening for possible liver toxic substances.

Acquired cystic disease of kidney with multiple renal and urothelial neoplasms

Acquired polycystic disease with concurrent development of renal cell tumours is a well documented complication of long term haemodialysis. We present a case of acquired polycystic disease with renal cell tumours and multifocal urothelial tumours. Only two similar cases have been recorded.

Chemically induced renal papillary necrosis and upper urothelial carcinoma. Part 1

In the past, renal papillary necrosis (RPN) has been commonly associated with long-term abusive analgesic intake, but over recent years a wide variety of industrially and therapeutically used chemicals have been shown to induce this lesion experimentally or in man. Destruction of the renal papilla may result in: (1) secondary degenerative cortical changes which precede chronic renal failure or (2) a rapidly metastasizing upper urothelial carcinoma, which has a very poor prognosis. This article will briefly review the published data on the morphology, function, and biochemistry of the normal renal medulla and the pathology associated with RPN, together with the secondary changes which give rise to cortical degeneration or epithelial carcinoma. It will then examine in detail those chemicals which have been reported to cause RPN in an attempt to delineate structure-activity relationships. Finally, the many different theories that have been proposed to explain the pathophysiology of RPN will be examined and an hypothesis will be put forward to explain the primary pathogenesis of the lesion and its secondary consequences.

Chemically induced renal papillary necrosis and upper urothelial carcinoma. Part 2

In the past, renal papillary necrosis (RPN) has been commonly associated with long-term abusive analgesic intake, but over recent years a wide variety of industrially and therapeutically used chemicals have been shown to induce this lesion experimentally or in man. Destruction of the renal papilla may result in: (1) secondary degenerative cortical changes which precede chronic renal failure or (2) a rapidly metastasizing upper urothelial carcinoma, which has a very poor prognosis. This article will briefly review the published data on the morphology, function, and biochemistry of the normal renal medulla and the pathology associated with RPN, together with the secondary changes which give rise to cortical degeneration or epithelial carcinoma. It will then examine in detail those chemicals which have been reported to cause RPN in an attempt to delineate structure-activity relationships. Finally, the many different theories that have been proposed to explain the pathophysiology of RPN will be examined and an hypothesis will be put forward to explain the primary pathogenesis of the lesion and its secondary consequences.

The effect of N-phenylanthranilic acid-induced renal papillary necrosis on urinary acidification and renal electrolyte handling

The oral administration of a suspension of N-phenylanthranilic acid (N-PAA), over the range of 0.5 to 2 mmol/kg for 14 consecutive days, caused a dose-related renal papillary necrosis (RPN), which involved no more than 30% of the medullary apex. This area of necrosis was no greater following daily doses of 3 and 5 mmol/kg of N-PAA for 14 days, but cortical degenerative changes were induced. The area of the necrotic lesion was greater in the left kidneys of individual rats than in the right kidneys. The apex-limited histopathological changes associated with the administration of low doses of N-PAA were not reflected by altered electrolyte or water homeostasis and only high doses of N-PAA caused significant changes. Urinary volume was significantly increased (in animals treated with 5 mmol/kg), whereas urinary osmolality (greater than 2 mmol/kg N-PAA), and Na+ (5 mmol/kg), K+ (5 mmol/kg), and Cl- (5 mmol/kg) excretion was decreased compared to controls. Blood urea nitrogen was increased at doses greater than 3 mmol/kg in association with cortical degenerative changes. When untreated rats were dosed orally with NH4Cl (400 mg/kg) there was a lag period between 0 and 2 hr (when no changes in H+ excretion occurred), but the urinary pH was depressed in the 2- to 4-hr collection period. Only those rats treated with the highest dose of N-PAA (5 mmol/kg) showed a significantly impaired urinary acidification after NH4Cl loading. There was, however, a statistically significant dose-related decrease in the excretion of Cl- following NH4Cl dosing, provided urine was sampled between 0 and 2 hr. These data highlight the failure of the commonly used renal function tests (such as urinary volume, osmolality, and electrolyte excretion) to reflect apex-limited RPN, unless cortical degenerative changes were also present. The dose-related depression of Cl- excretion in the 0- to 2-hr period following oral NH4Cl loading, suggests that appropriately timed sampling of this urinary anion could offer an improved criterion for the diagnosis of RPN.

The role of metabolic activation of analgesics and non-steroidal anti-inflammatory drugs in the development of renal papillary necrosis and upper urothelial carcinoma

There has been no cogent hypothesis to explain the molecular basis of analgesic and non-steroidal anti-inflammatory drug (NSAID) associated renal papillary necrosis (RPN) and upper urothelial carcinoma (UUC). The microsomal cytochrome P-450 enzyme system may generate reactive intermediates which promote pathophysiological effects in the lung, liver and renal cortex, but the absence of P-450 activity in the medulla suggests that it is unlikely that similar events lead to RPN and UUC. Other enzymes (eg. peroxidases) convert substituted aromatics into benzoquinoneimines (an intermediate that has previously been defined in P-450-mediated toxicity). The medulla is rich in fatty acid peroxidases involved in the metabolism of arachidonic acid. NSAID and analgesics interact with key enzymes in this pathway, which could lead to the co-oxygenation of exogenous and endogenous compounds via the peroxidase, lipoxygenase, or prostaglandin hydroperoxidase enzymes. The generation of reactive molecules in the medulla could explain both RPN and UUC via the alkylation of macromolecules. The formation of free radicals would give rise to extensive lipid peroxidation, (there are large quantities of free polyunsaturated fatty acids in the medullary interstitial cells), an event of major potential importance to local cell destruction and genotoxic effects. At present this proposed mechanism of co-oxygenation offers the most attractive working hypothesis to explain the molecular pathogenesis of both RPN and UUC.

Renal effects of antipyretic analgesics

Most antipyretic analgesics can cause acute nephrotoxic effects, including acute tubular necrosis, acute interstitial nephritis, glomerular toxicity, and functional changes, such as "salicyl edema," following large doses of sodium salicylate. Most functional changes are related to acute suppression of prostaglandin synthesis, "the acute prostaglandin-effect," and have been primarily noted with the use of indomethacin. The association between prolonged and excessive consumption of compound analgesics and the development of renal disease and renal failure, characterized by renal papillary necrosis, is now well established. Studies in several countries have shown that the incidence of analgesic nephropathy as an indication for dialysis and transplantation corresponds to the per capita consumption of phenacetin in compound analgesics. Analgesic nephropathy, which is part of a wider clinical syndrome, the analgesic syndrome, is uncommon following the use of single analgesics. Analgesic nephropathy and the analgesic syndrome are discussed in detail, including the development of uroepithelial tumors.

Epithelial abnormalities in the renal pelvis in experimental hydronephrosis and pyelonephritis

Unilateral hydronephrosis was induced by temporary ligature of the left ureter in 29 rabbits. In 21 animals so treated, chronic pyelonephritis was simultaneously induced by intravenous application of a suspension of E. coli. Histologic examination of renal pelvic epithelia in animals killed four weeks after the surgical intervention, revealed the following features: 1. Simple hyperplasia of urothelium in 12 cases, 2. atypical hyperplasia - (dysplasia) of urothelium in 10 cases, 3. v. Brunn's nests in 20 renal pelvises; 11 cases of cystic pyelitis, all combined with Brunn's nests, 4. metaplastic transformation of visceral mono- or bilayered epithelium into multi-layered urothelium-like structures in 19 renal pelvises. These changes are observed almost exclusively in the left renal pelvis of animals subjected to temporary ureteral ligature. Atypical urothelial hyperplasia is found only together with chronic pyelonephritis. Hyperplastic and dysplastic epithelial changes in the renal pelvis, the formation of Brunn's nests, and cystic pyelitis are interpreted as sequelae of postrenal obstruction or concomitant chronic inflammation.

Phenacetin abuse and malignant tumors. An autopsy study covering 25 years (1953-1977)

The findings presented in this study are based on 29.226 autopsies performed (between 1953 and 1977) at Basel University on adult inhabitants of Basel, from which 409 urinary tract tumors (UTT) and 513 phenacetin abusers (PA) were discovered. There were 44 (8.6%) PA with UTT which, when compared with the control group (1.27%), represents a statistically significant increased incidence. Of the 50 UTT in PA, 52% occurred in the bladder, 6% in the ureter, and 42% in the renal pelvis. The induction time for tumors of the urinary bladder was about 27 years, and for tumors of the renal pelvis about 20 years. The commonest tumors arising in PA were invasive solid and non-invasive papillary urothelial carcinomas. PA with UTT died earlier than nonabusers but had metastases as frequently as nonabusers. Analgesic nephropathy was not always an accompanying disease. The daily dose of g/phenacetin in tumor patients in general, and in patients with tumors of the urinary bladder in particular, was about 1 g lower than in patients with analgesic nephropathy (without tumors) and in those with tumors of the renal pelvis. Thus, for the localization of the tumors, the daily dose seems to be more important than the total dose. Our investigation proved that not only tumors of the renal pelvis, but also of the ureter and the urinary bladder, are significantly more frequent in PA than in nonabusers. It is suspected that despite restriction of the over-the-counter sale of phenacetin-containing analgesics and even after stopping any analgesic abuse, UTT will further increase due to the longer induction time. Routine cytological screening tests of the urine are recommended for all known PA. A prescription for all phenacetin- and paracetamol-containing analgesics is necessary.

Analgesics and cancer of the renal pelvis in New South Wales

A lifetime history of analgesics and tobacco consumption was obtained by a questionnaire completed at interview from 67 patients with carcinoma of the renal pelvis (40 women, 27 men) and 180 control subjects drawn from two sources, friends of patients and persons attending a health screening clinic. Regular consumption of analgesics conferred a tenfold relative risk of renal pelvic cancer in women and in men a risk ratio of 4-8. The fraction of cases for which analgesic consumption was an attributable risk was 0.74 in women and 0.43 in men. The effect of tobacco, much less than that of analgesics, was significant only in women (risk ratio approximately four; attributable risk 0.4), and no dose-response relationship was demonstrated. Relative excess risks suggested a synergistic effect when both analgesics and tobacco had been consumed. Standardized risk ratios indicated a dose-response relationship for both phenacetin-containing and non-phenacetin analgesics: moderate consumption doubled the risk of renal pelvic cancer, and heavy consumption increased at risk to 6-16 times that for noncomsumers.

Inhibition of DNA synthesis and alteration to DNA structure by the phenacetin analog p-aminophenol

p-Aminophenol a structural analog and minor metabolite of phenacetin has previously been shown to be a potent nephrotoxic agent. In this report we have shown that p-aminophenol has a marked effect on DNA function and structure. DNA synthesis was inhibited in a dose-dependent manner in human lymphoblastoid cells after exposure to p-aminophenol. Results suggest that DNA synthesis is inhibited by the action of p-aminophenol on DNA structure. At low concentrations of p-aminophenol a reduction in the degree of supercoiling of cellular DNA is observed, as determined by sedimentation under neutral conditions. However at higher concentrations an increase in sedimentation of nucleoids (supercoiled molecules) is obtained which is indicative of an increased level of supercoiling or a more compact structural form of DNA due to folding or aggregation. The number of single strand breaks in DNA, when determined by sedimentation in alkaline sucrose gradients, increases with increasing dose of p-aminophenol. The increase in strand breakage observed at lower concentrations of p-aminophenol agrees with the reduced sedimentation rate obtained under neutral conditions. At higher concentrations of p-aminophenol the extent of breakage of DNA increases under alkaline conditions but an increase in sedimentation occurs under neutral conditions.

Renal pelvic neoplasms and atypical urothelium in patients with end-stage analgesic nephropathy

In a series of 772 renal transplant patients, 84 had analgesic nephropathy (AN). Four of them had renal pelvic carcinoma. The incidence of atypical urothelial changes of the renal pelvis was studied in 56 AN patients, the majority nephrectomized before or shortly after the renal transplantation. Urothelial atypia, usually bilaterally, was found in 27 patients. Multiple sections resulted in an even higher incidence (8/9). No atypical changes were found in normal kidneys or in end-stage diseased kidneys with other diseases, or in chronically rejected renal allografts. These findings further strengthen the association between intake of phenacetin-containing analgesics and the development of renal pelvic tumors. Patients with end-stage analgesic nephropathy are a high-risk group for developing urinary tract tumors and should be subjected to endoscopic and cytologic surveillance. After renal transplantation, prophylactic bilateral nephroureterectomy is advocated.

PaperChase: a computer program to search the medical literature

This report describes PaperChase, a computer program that permits users to search medical literature by author's name, journal of publication, title word, or medical subject heading (MeSH term), as indexed by the National Library of Medicine. PaperChase was installed in the medical library of Beth Israel Hospital in Boston, with a data base of 400,000 references--nearly all the articles shelved there. During the first year of operation, 1032 medical students, house officers, practicing physicians, and other library users, without formal instruction or user's manual, conducted 8459 searches and displayed 399,821 references, 97,769 of which they selected for printing. Among users who conducted an initial search, 49 per cent returned to complete five or more searches, and 14 per cent returned to complete 20 or more. The large number of satisfied users and the low installation and operating costs suggest that PaperChase could be a valuable means of providing widespread computerized bibliographic retrieval.

Carcinogenicity of analgesics: long-term treatment of Sprague-Dawley rats with phenacetin, phenazone, caffeine and paracetamol (acetamidophen)

Six groups of male Sprague-Dawley rats were treated with phenacetin, phenazone or caffeine in the diet or with combinations of these chemicals. Another group received paracetamol in the diet and a further group received only the control diet. The rats were treated for up to 117 weeks. Renal pelvic tumors were only seen in rats treated with phenacetin or phenazone alone or in combination with caffeine, phenazone having slightly greater activity toward the urinary tract than phenacetin. Phenacetin, however, had a greater overall carcinogenic effect, inducing 31 malignant tumors. The urinary tract and the kidneys had the highest incidence of tumor followed by squamous-cell carcinomas of the head and neck. Half of the rats treated with phenacetin, phenazone and caffeine in combination developed hepatomas. The explanation may be that the addition of phenazone and caffeine altered the metabolism of phenacetin, increasing the production of N-hydroxyphenacetin, a known liver carcinogen. The justification of using phenacetin as a human analgesic must be seriously questioned, and further studies with phenazone are required.

Unsuspected analgesic nephropathy in transitional cell carcinoma of the upper tract: a morphological study

Analgesic nephropathy is known to have a high incidence in Australia where, following the experience in Scandinavia, reports have been published for some time recording the association between analgesic nephropathy and urothelial malignancies. The morbid anatomical features of analgesic nephropathy are now sufficiently well accepted to allow a retrospective study of unselected nephrectomies for transitional cell carcinoma of the renal pelvis and ureter, in order to assess the incidence of analgesic-type changes in this well defined group of malignancies. The records of a large general histopathology department between 1972-1978 were searched and 24 consecutive transitional cell carcinomas in these sites treated by nephrectomy were selected for study. Of these, 21 were suitable for assessment and on review were shown to comprise II cases with papillary changes acceptable as analgesic in type and five which were suggestive of early analgesic change. Of these 16, seven were female, only two were known analgesic abusers and five were recorded as consuming analgesics on a regular basis. These findings suggest that analgesics may play a significant role in the pathogenesis of urothelial malignancy in the general population.