Suggestive evidence for the induction of colonic aberrant crypts in mice fed sodium nitrite.

A reported linkage between processed (nitrite-treated) meat products and the incidence of colon cancer could be due to sodium nitrite (NaNO2) itself or to N-nitroso compounds produced from the nitrite. Exposure to nitrite occurs due to residual nitrite in processed meat and to salivary nitrite arising by reduction of nitrate in vegetables and drinking water. Here we tested whether NaNO2 could induce colonic aberrant crypts (ABC) or ABC foci (ACF), which are putative precursors of colon cancer. We fed NaNO2 in drinking water for 20-25 wk to groups of 8-20 adult female mice. After sacrifice, ABC and ACF were counted in 2-cm distal colonic segments. In Experiment 1, no significant differences in ABC/ACF induction were seen between groups of 13-14 A/J mice fed 0, 0.5, or 1.0 g NaNO2/l drinking water. NaNO2 also did not affect fasting blood glucose levels. In Experiment 2, we fed 0, 1.0, 1.25, or 1.5 g NaNO2/l water to groups of 15 CF-1 mice. Five of the mice fed 1.5 g NaNO2/l showed ABC, whereas all other groups showed only 0-2 ABC/group, including 0 ABC for the group fed 1.25 g NaNO2/l. Overall statistical analysis indicated a dose-response p trends of 0.04. Pairwise comparison of ABC between groups fed 1.25 and 1.5 g NaNO2/l showed p 0.02 for both ABC and ACF, but a similar comparison between the untreated and 1.5 g/l groups showed no significant effects. In Experiment 3, hot dogs (18% of diet), which were fed to CF-1 mice previously treated with azoxymethane, inhibited ABC and ACF induction, but this effect was not significant (P = 0.10-0.12). In conclusion, these results support the view that NaNO2 may be a risk factor for colon carcinogenesis.

Urinary excretion of N-nitroso compounds in rats fed sodium nitrite and/or hot dogs.

Nitrite-treated meat is a reported risk factor for colon cancer. Mice that ingested sodium nitrite (NaNO2) or hot dogs (a nitrite-treated product) showed increased fecal excretion of apparent N-nitroso compounds (ANC). Here, we investigated for the first time whether rats excrete increased amounts of ANC in their urine after they are fed NaNO2 and/or hot dogs. Rats were treated for 7 days with NaNO2 in drinking water or were fed hot dogs. Their 24 h urine samples were analyzed for ANC by thermal energy analysis on days 1-4 after nitrite or hot dog treatment was stopped. For two rats fed 480 mg NaNO2/L drinking water, mean urinary ANC excretion on days 1-4 was 30, 5.2, 2.5, and 0.8 nmol/day, respectively. For two to eight rats/dose given varied NaNO2 doses, mean urinary ANC output on day 1 increased from 0.9 (for no nitrite) to 37 (for 1000 mg NaNO2/L drinking water) nmol ANC/day. Urine samples of four rats fed 40-60% hot dogs contained 12-13 nmol ANC on day 1. Linear regression analysis showed highly significant correlations between urinary ANC excretion on day 1 after stopping treatment and varied (a) NaNO2 level in drinking water for rats fed semipurified or commercials diet and (b) hot dog levels in the diet. Some correlations remained significant up to 4 days after nitrite treatment was stopped. Urinary output of ANC precursors (compounds that yield ANC after mild nitrosation) for rats fed semipurified or commercial diet was 11-17 or 23-48 µmol/day, respectively. Nitrosothiols and iron nitrosyls were not detected in urinary ANC and ANCP. Excretion of urinary ANC was about 60% of fecal ANC excretion for 1 to 2 days after NaNO2 was fed. Administered NaNO2 was not excreted unchanged in rat urine. We conclude that urinary ANC excretion in humans could usefully be surveyed to indicate exposure to N-nitroso compounds.

Calcium inhibits promotion by hot dog of 1,2-dimethylhydrazine-induced mucin-depleted foci in rat colon.

Epidemiology suggests that processed meat is associated with colorectal cancer risk, but few experimental studies support this association. We have shown that a model of cured meat made in a pilot workshop promotes preneoplastic lesions, mucin-depleted foci (MDF) in the colon of rats. This study had two aims: to check if real store-bought processed meats also promote MDF, and to test if calcium carbonate, which suppresses heme-induced promotion, can suppress promotion by processed meat. A 14-day study was done to test the effect of nine purchased cured meats on fecal and urinary biomarkers associated with heme-induced carcinogenesis promotion. Fecal water from rats given hot dog or fermented raw dry sausage was particularly cytotoxic. These two cured meats were thus given to rats pretreated with 1,2-dimethylhydrazine, to evaluate their effect on colorectal carcinogenesis. After a 100-days feeding period, fecal apparent total N-nitroso compounds (ATNC) were assayed and colons were scored for MDF. Hot dog diet increased fecal ATNC and the number of MDF per colon compared with the no-meat control diet (3.0 ± 1.7 vs. 1.2 ± 1.4, p < 0.05). In a third study, addition of calcium carbonate (150 µmol/g) to the hot dog diet decreased the number of MDF/colon and fecal ATNC compared with the hot dog diet without calcium carbonate (1.2 ± 1.1 vs. 2.3 ± 1.4, respectively, p < 0.05). This is the first experimental evidence that a widely consumed processed meat promotes colon carcinogenesis in rats. It also shows that dietary prevention of this detrimental effect is possible.

Renal Infiltration as a Primary Presentation of Burkitt Lymphoma Secondary to Systemic Lupus Erythematosus: A Rarity Unto a Rarity.

Burkitt lymphoma (BL) is a highly aggressive non-Hodgkin B-cell lymphoma characterized by the translocation and deregulation of the MYC (MyeloCytomatosis) gene on chromosome 8. Three distinct clinical forms of BL are recognized: endemic (African), sporadic (non-endemic), and immunodeficiency-associated. Bilateral renal infiltration leading to acute kidney injury (AKI) is a rare initial presentation of BL. Diagnosis is usually made after evaluating the histology and immunophenotyping of the affected tissue. We report a case of a 46-year-old male who presented with symptoms of AKI resulting from infiltrative disease, a primary presentation of lymphoma. The patient was a known case of systemic lupus erythematosus (SLE) for the last five years and was referred to the nephrology department due to acute elevation in creatinine, from 0.8 mg/dL to 3.57 mg/dL. On physical examination, there was no lymphadenopathy. Nephrology and SLE workup revealed low complement protein levels and absolute neutrophils, lymphocytes, and metamyelocytes. Renal ultrasound (USG) showed both kidneys with symmetric and edematous appearance. Biopsy affirmed high-grade B-cell lymphoma, positive for BCL-6 (B-cell leukemia/lymphoma) and CD-10 (cell surface marker) and negative for BCL-2 (B-cell leukemia/lymphoma). PET (positron emission tomography) scan showed extensive hypermetabolic lymphadenopathy in multiple areas. The patient was started on chemotherapy and on continuous renal replacement therapy. He improved clinically, and his creatinine lowered down to 0.8 mg/dL. Repeat USG showed decreased edematous appearance of both kidneys. Primary renal infiltration by BL is a rare presentation in adults. Prompt renal biopsy will change the course of treatment and can affect the prognosis. It is thoroughly advised to keep this malignancy in mind when making a diagnosis for AKI.

Primary Cutaneous Nocardiosis: A Rare Presentation of Nocardiosis.

Nocardia is an uncommon gram-positive, weakly acid-fast bacterium that causes systemic or localized suppurative disease in humans and animals. Nocardiosis is typically regarded as an opportunistic infection, but approximately one-third of the patients are immunocompetent. The most common presentation is pulmonary disease (39%) followed by systemic involvement, defined as involvement of more than two sites; cutaneous presentation constitutes only 8% of the cases. Nocardia is widely distributed geographically; however, in the US, it is mostly found in warm and dry areas of South West and South East. We present a perfect case of cutaneous nocardiosis of a 70-year-old male, who presented with a traumatic splinter injury, leading to pustules formation on the right index finger, along with erythema and induration of the right arm. The patient was empirically diagnosed and treated for cellulitis, with amoxicillin and clavulanic acid, resulting in deterioration of the wound. The patient underwent incision and drainage and wound culture grew nocardia. The index of suspicion should be kept in mind while treating infectious blisters which have failed outpatient cellulitis treatment, immunocompromised hosts, and in nocardia prevalent regions.

Rheumatoid Vasculitis: Is It Always a Late Manifestation of Rheumatoid Arthritis?

Rheumatoid vasculitis (RV) is an infrequent complication of longstanding severe rheumatoid arthritis (RA). The active vasculitis associated with rheumatoid disease occurs in about 1%-5% of the patient population. RV is a manifestation of "extra-articular" rheumatoid arthritis and involves the small- and medium-sized arteries in the body. Newer RA treatments, including biologic therapies, offer a broader array of potential therapeutic options, although no controlled trials exist to guide treatment. In general, following tissue confirmation of the diagnosis, the severity of organ involvement and disease manifestations can guide treatment decisions. We want to alert clinicians of this unique yet severe complication of RA which has high morbidity and mortality. We describe a thought-provoking case of a 44-year-old male with past medical history (PMH) of hypertension who presented with over three-month history of lower extremity (LE) swelling, discoloration, and ulceration. Arthralgias with constitutional symptoms (fatigue, weight loss), large pericardial effusion, was found to have leukocytoclastic vasculitis along with rheumatoid factor (RF) >650, and anti-cyclic citrullinated peptide (anti-CCP) antibodies >300, low C4 and normal C3. Pericardial fluid appeared serous, exudative, showed histiocytes, multinucleated giant cells and necrotic debris consistent with rheumatoid effusion. Skin, right shin, punch biopsy showed epidermal necrosis from underlying occlusive vasculopathy. Skin, left lower back, punch biopsy showed focal leukocytoclastic vasculitis. The patient was started on high dose steroids with marked improvement in the symptoms, Rituximab was planned awaiting QuantiFERON to be negative. Pan-CT angiography of the whole body was negative for any vascular changes ruling out polyarteritis nodosa (PAN).

Targeting the NF-κB and mTOR pathways with a quinoxaline urea analog that inhibits IKKß for pancreas cancer therapy.

PURPOSE: The presence of TNF-α in approximately 50% of surgically resected tumors suggests that the canonical NF-κB and the mTOR pathways are activated. Inhibitor of IκB kinase ß (IKKß) acts as the signaling node that regulates transcription via the p-IκBα/NF-κB axis and regulates translation via the mTOR/p-S6K/p-eIF4EBP axis. A kinome screen identified a quinoxaline urea analog 13-197 as an IKKß inhibitor. We hypothesized that targeting the NF-κB and mTOR pathways with 13-197 will be effective in malignancies driven by these pathways. EXPERIMENTAL DESIGN: Retrospective clinical and preclinical studies in pancreas cancers have implicated NF-κB. We examined the effects of 13-197 on the downstream targets of the NF-κB and mTOR pathways in pancreatic cancer cells, pharmacokinetics, toxicity and tumor growth, and metastases in vivo. RESULTS: 13-197 inhibited the kinase activity of IKKß in vitro and TNF-α-mediated NF-κB transcription in cells with low-µmol/L potency. 13-197 inhibited the phosphorylation of IκBα, S6K, and eIF4EBP, induced G1 arrest, and downregulated the expression of antiapoptotic proteins in pancreatic cancer cells. Prolonged administration of 13-197 did not induce granulocytosis and protected mice from lipopolysaccharide (LPS)-induced death. Results also show that 13-197 is orally available with extensive distribution to peripheral tissues and inhibited tumor growth and metastasis in an orthotopic pancreatic cancer model without any detectable toxicity. CONCLUSION: These results suggest that 13-197 targets IKKß and thereby inhibits mTOR and NF-κB pathways. Oral availability along with in vivo efficacy without obvious toxicities makes this quinoxaline urea chemotype a viable cancer therapeutic.

Diuron-induced rat bladder epithelial cytotoxicity.

Diuron, a substituted urea herbicide, is carcinogenic to the rat urinary bladder at high dietary levels (2500 ppm). To further elucidate the mode of action, this study aimed to determine the time course and sequence of bladder cytotoxic and proliferative changes induced by diuron treatment of male Wistar rats. Rats were randomized into two groups (control and 2500 ppm diuron) and treated for 28 days. Ten rats from each group were terminated on each of study days 1, 3, 7, or 28. Scanning electron micro scopy (SEM) showed urothelial cell swelling beginning on day 1, and by day 28, showed extensive necrosis, exfoliation and piling up of cells suggestive of hyperplasia. No difference in the bromo deoxyuridine labeling index was detected. In a second experiment, rats were randomized into control and diuron-treated groups and treated for 7 days or 8 weeks. After 7 days, transmission electron microscopy showed cell degenerative changes and distention of the cytoplasm, organelles, and nuclei characteristic of cytolysis. This resulted in protrusion of the superficial cells into the lumen, corresponding to the cell swelling observed previously by SEM. After 8 weeks, bladders in the diuron-treated group showed an increased incidence of simple hyperplasia by light microscopy (6/10, p < 0.05) compared with controls (0/10) and a significantly different SEM classification. In summary, our results support the hypothesis that urothelial cytotoxicity followed by regenerative cell proliferation are the sequential key events that occur with high-dose diuron exposure in rats.

Mode of action of pulegone on the urinary bladder of F344 rats.

Essential oils from mint plants, including peppermint and pennyroyal oils, are used at low levels as flavoring agents in various foods and beverages. Pulegone is a component of these oils. In a 2-year bioassay, oral administration of pulegone slightly increased the urothelial tumor incidence in female rats. We hypothesized that its mode of action (MOA) involved urothelial cytotoxicity and increased cell proliferation, ultimately leading to tumors. Pulegone was administered by gavage at 0, 75, or 150 mg/kg body weight to female rats for 4 and 6 weeks. Fresh void urine and 18-h urine were collected for crystal and metabolite analyses. Urinary bladders were evaluated by light microscopy and scanning electron microscopy (SEM) and bromodeoxyuridine (BrdU) labeling index. Pulegone and its metabolites, piperitenone, piperitone, menthofuran, and menthone, were tested for cytotoxicity in rat (MYP3) and human (1T1) urothelial cells by the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. No abnormal urinary crystals were observed by light microscopy. Urine samples (18-h) showed the presence of pulegone, piperitone, piperitenone, and menthofuran in both treated groups. By SEM, bladders from treated rats showed superficial necrosis and exfoliation. There was a significant increase in the BrdU labeling index in the high-dose group. In vitro studies indicated that pulegone and its metabolites, especially piperitenone, are excreted and concentrated in the urine at cytotoxic levels when pulegone is administered at high doses to female rats. The present study supports the hypothesis that cytotoxicity followed by regenerative cell proliferation is the MOA for pulegone-induced urothelial tumors in female rats.