Peroxisome proliferator-induced hepatocarcinogenesis: histochemical analysis of ciprofibrate-induced preneoplastic and neoplastic lesions for gamma-glutamyl transpeptidase activity

Previous studies revealed that putative preneoplastic and neoplastic lesions induced in the liver by Wy-14,643, a peroxisome proliferator, were gamma-glutamyl transpeptidase (GGT) negative. For ascertainment as to whether phenotypes of foci and carcinomas induced by all peroxisome proliferators are similarly GGT negative, altered areas (AAs), neoplastic nodules (NNs), and hepatocellular carcinomas (HCCs) induced in the livers of male F344 rats by chronic dietary administration of ciprofibrate (0.025% wt/wt in chow; CAS: 52214-84-3) were analyzed histochemically for GGT activity. Eighty-nine percent of AAs, 91% of NNs, and 91% of HCCs were GGT negative. The GGT-negative property of these various hepatic preneoplastic and neoplastic lesions persisted at 8 weeks after the withdrawal of ciprofibrate treatment. The results of this study indicate that the absence of GGT activity is a common feature in hepatic lesions induced by structurally unrelated peroxisome proliferators and is not related to the drug toxicity. The proposal was made that peroxisome proliferators do not derepress the activity of the GGT gene during hepatocarcinogenesis in the rat.

Analysis of peroxisome proliferator-induced preneoplastic and neoplastic lesions of rat liver for placental form of glutathione S-transferase and gamma-glutamyltranspeptidase

Structurally unrelated peroxisome proliferators induce altered areas (AA), neoplastic nodules (NN), and hepatocellular carcinomas (HCC) in rats and mice. In this study we have examined several AA, NN, and HCC induced by Wy-14,643 and ciprofibrate in rats for gamma-glutamyltranspeptidase (GGT) and the placental form of glutathione S-transferase (GST-P) by histochemical and immunohistochemical procedures, respectively. In Wy-14,643-treated animals 96-100% of NN and HCC was negative for both GGT and GST-P. Eighty-seven % of the AA was negative for both GGT and GST-P, and only 2% was positive for both the marker enzymes. In ciprofibrate-treated animals 52% and 75% of AA were negative for GST-P and GGT, respectively, and 16% was positive for both the enzymes. However, a large majority of NN and HCC (more than 95%) was devoid of both these marker enzymes. Thus these studies clearly indicate that the hepatic lesions induced by peroxisome proliferators display different phenotypic properties as compared to the lesions induced by commonly used classical liver carcinogens. We conclude that GGT and GST-P are not the ideal markers for identifying AA, NN and HCC induced by peroxisome proliferators.

Induction of altered hepatic foci in rats by the administration of hypolipidemic peroxisome proliferators alone or following a single dose of diethylnitrosamine

The effect of feeding hypolipidemic peroxisome proliferators on the induction of altered hepatic foci (AHF) in Fischer rats was studied in order to determine whether such agents can induce or promote the development of AHF. In the first study, rats were fed ciprofibrate (10 mg/kg/day) for 1 yr. AHF, neoplastic nodules, and hepatocellular carcinomas were induced. The presence of putative gamma-glutamyltranspeptidase (GGT) activity was numerically the most common marker, although it was absent in larger foci and nodules. A deficiency in canalicular ATPase and glucose-6-phosphatase provided the best markers for the larger foci and nodules. In the second study, rats were subjected to partial hepatectomy, and half of the animals were then intubated with diethylnitrosamine (10 mg/kg). One wk later, rats were fed Wy-14,643 at concentrations of 0, 0.05, and 0.1% in the diet for 6 mo. At 6 mo, the number and volume of foci were increased by the feeding of Wy-14,643 after partial hepatectomy alone and were greatly increased when Wy-14,643 was fed after partial hepatectomy/diethylnitrosamine administration. Canalicular adenosine triphosphatase and glucose-6-phosphatase deficiencies were the most common markers of AHF, and AHF of these phenotypes occupied practically all of the focal volume. The larger AHF did not express GGT, and those foci exhibiting GGT were much less common and occupied very little volume. The absence of the GGT protein itself, as opposed to an inhibition of GGT activity, was verified by immunohistochemical staining using an antibody to GGT. These studies show that hypolipidemic peroxisome proliferators can stimulate an increase in AHF following a single dose of diethylnitrosamine and a mitotic stimulus, and they thus can act as promoters in two-stage liver carcinogenesis. GGT is a poor marker for identifying AHF induced by peroxisome proliferators during the early, premalignant phase of hepatocarcinogenesis.

Induction of peroxisome proliferation in hepatocytes transplanted into the anterior chamber of the eye. A model system for the evaluation of xenobiotic-induced effects

The effect of two hypolipidemic peroxisome proliferators, ciprofibrate and di(2-ethylhexyl)phthalate (DEHP), on hepatocytes transplanted into the anterior chamber of the eye was examined. Young male F-344 rats transplanted with dissociated hepatocytes were fed either a control diet or a diet containing 0.025% ciprofibrate or 2% DEHP. After 4-5 weeks of treatment, all rats were sacrificed and the transplanted liver cells and portions of homotopic liver were processed for light and electron microscopy and for immunofluorescence microscopy. Morphometric analysis of transplanted hepatocytes showed a ninefold and fivefold increase in the volume density of peroxisomes in ciprofibrate and DEHP-fed rats, respectively. Indirect immunofluorescence studies revealed a marked induction of peroxisome-associated enzymes. From these data it is concluded that hepatic peroxisome proliferators cross the blood aqueous humor barrier and the transplanted hepatocytes in the anterior chamber of the eye retain their ability to recognize and respond to peroxisome proliferators.

DNA synthesis in exocrine and endocrine pancreas after partial hepatectomy in Syrian golden hamsters

3H-thymidine autoradiography showed an enhanced DNA synthesis in acinar and islet cells of pancreas after partial hepatectomy in syrian golden hamsters. A significant nuclear labeling index of acinar cells was observed between 48 and 84 h and reached control levels by 120 h. An increased labeling index of islet cells was also observed, however, this increase was not statistically significant. These results indicate growth factor(s) produced after partial hepatectomy is capable of inducing DNA synthesis in pancreas.

Increased resistance of peroxisome proliferator-induced hepatic lesions to iron overload in rats

Altered areas (AA), neoplastic nodules (NN) and hepatocellular carcinomas (HCC) induced by chronic administration of ciprofibrate and Wy-14,643 were examined for iron accumulation after systemic iron overload. Eighty percent of AA, 90% NN and 100% HCC showed increased resistance to iron accumulation. However, marked heterogeneity was observed in the amount of iron from area to area within the same lesion with some cells containing no iron, while others showing blue reaction to iron. These findings indicate, that putative preneoplastic and neoplastic hepatic lesions induced by peroxisome proliferators exclude iron in a fashion similar to that of hepatic nodules and carcinomas induced by DNA damaging carcinogens.

Vesical calculi associated with vesicovaginal fistulas: management considerations

Vesical calculi were detected in 5 patients with a vesicovaginal fistula. Of these patients 3 had undergone unsuccessful repair of the fistula previously. The predisposing factors for vesical calculous formation in patients with a vesicovaginal fistula in whom urine leaks continuously into the vagina and urinary stasis does not occur in the bladder, as in patients with neurogenic bladder dysfunction or bladder outlet obstruction, are a foreign body (for example nonabsorbable suture material used during previous surgery), incrustation around an indwelling catheter and infection. The vesical calculus is removed transvaginally after enlarging the fistula by a vertical incision at the 6 o'clock position. The incised edges do not usually bleed because of fibrosis and scar formation, and they need not be approximated at that operation. Indwelling catheter drainage is not necessary after transvaginal cystolithotomy in this situation. This operation is preferable to suprapubic cystolithotomy, which may lead to more morbidity from urine leakage in the retropubic space and subsequent fibrosis, in addition to producing bladder scarring, hindering any future reconstructive surgery requiring the use of vesical flaps. Transvaginal cystolithotomy is contraindicated when the fistula is situated close to the bladder neck (for fear of damaging the bladder neck and the vesical continence mechanism) or when the stone is large. Repair of the fistula is undertaken after an interval of 3 months to allow for resolution of stone-induced edema and friability of the vesical wall.

Pancreatic lesions induced by a single dose of N-nitrosobis(2-oxopropyl)amine and selection by resistance to cytotoxicity

The experiments reported here were undertaken to ascertain whether the principle of the selection and rapid emergence of carcinogen-initiated cells based on their resistance to cytotoxicity demonstrated in rat liver is applicable to hamster pancreas. Hamsters injected with a single dose of 70 mg/kg body weight of the pancreatic carcinogen, N-nitrosobis(2-oxopropyl)amine, were subjected to pancreatic injury and regeneration induced by DL ethionine followed by methionine rescue while on a continuous daily regimen of 10 mg/kg body weight of N-nitroso-2,6-dimethylmorpholine by gavage. Randomly selected animals were killed weekly from the 4th week following the induction of regeneration through the 10th week. This carcinogenic schedule significantly decreased the time of emergence of cell injury, cell death, and proliferative, preneoplastic, and neoplastic lesions of the exocrine pancreas. Carcinoma in situ and invasive adenocarcinoma of pancreatic ducts appeared during the 7th and 8th week after induction of pancreatic regeneration, earlier than results obtained with multiple dose carcinogenesis experiments.

Standardization and demonstration of antibody-coated Candida in urine by direct immunofluorescence test

Acetone, carbontetrachloride, ethyl alcohol, mixture of ethyl alcohol and acetone, and heat were assessed for fixative property for direct immunofluorescent (IF) staining of antibody-coated Candida cells. The results indicated that ethyl alcohol was the most suitable fixative for the test. Antisera containing 16 units of Candida albicans type A agglutinin were found essential to get optimal detectable fluorescence of antibody-coated yeast cells. IF test showed cross reactivity between the yeasts of C. albicans and C. tropicalis. However, there was no cross reactivity with the conidia of A. flavus. The direct IF test could demonstrate antibody-coated yeast cells and pseudomycelia in deposits of urine in the direct smear. It correlated well with microscopy and culture studies. At times, it could demonstrate the antibody-coated yeasts earlier than routine significant culture. It could also differentiate the significant from non-significant fungal isolates from urine.

Comparison of hepatic peroxisome proliferative effect and its implication for hepatocarcinogenicity of phthalate esters, di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipate with a hypolipidemic drug

Peroxisome proliferation is inducible in hepatocytes of rodent and nonrodent species by structurally dissimilar hypolipidemic drugs and certain phthalate ester plasticizers. The induction of peroxisome proliferation appears to be a tissue specific response limited largely to the hepatocyte. Peroxisome proliferation is associated with increases in the activity of the H2O2-generating peroxisomal fatty acid beta-oxidation system and in the amount of peroxisome proliferation-associated 80,000 MW polypeptide (PPA-80). Chronic administration of these non-DNA damaging and nonmutagenic peroxisome proliferators to rats and mice results in the development of hepatocellular carcinomas. Comparative morphometric and biochemical data from rats treated with varying dose levels of ciprofibrate, a hypolipidemic drug, and di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipate, the widely used plasticizers, indicate that the hepatocarcinogenic potency of these agents is correlatable with their ability to induce peroxisome proliferation, peroxisomal beta-oxidation and PPA-80. Available evidence strongly favors the role of peroxisome proliferation-associated oxidative stress in the induction of liver tumors by peroxisome proliferators.

Induction of hepatocytes in the pancreas of copper-depleted rats following copper repletion

Pancreatic hepatocytes are induced in rats maintained on copper-deficient diet containing 0.6% D-penicillamine for 8-10 weeks, followed by copper repletion. These induced hepatocytes are morphologically and functionally very similar to parenchymal cells of the liver. Immunofluorescence stains demonstrated the presence of albumin and catalase in these cells. Stains for pancreatic enzymes and hormones were negative. As expected, the hypolipidemic compound, ciprofibrate, induced peroxisome proliferation in these cells. These results indicate that a simple depletion and repletion of copper can trigger transdifferentiation in the pancreas of adult rats.

Characterization of pancreatic-type tissue in the liver of rat induced by polychlorinated biphenyls

Pancreatic-type tissue induced in the livers of rats treated with polychlorinated biphenyls was characterized by transmission electron microscopy and high-resolution immunocytochemistry. The cells of pancreatic-type tissue were arranged as acini and in small groups. By electron microscopy the pancreatic-type tissue showed features very similar to normal pancreatic acinar tissue, such as well developed rough endoplasmic reticulum (RER), large numbers of mature zymogen granules, and a basally located nucleus. Protein A-gold imunocytochemical technique showed localization of amylase and trypsinogen over the zymogen granules and RER. These findings confirm that this tissue in the liver is morphologically and functionally identical to pancreatic acinar tissue.

Duct-like morphogenesis of Longnecker pancreatic acinar carcinoma cells maintained in vitro on seminiferous tubular basement membranes

We have investigated the behavior of dissociated cells of a moderately differentiated Longnecker transplantable pancreatic acinar carcinoma (Longnecker et al., Cancer Lett., 7: 197-202, 1979) maintained in vitro on acellular seminiferous tubular basement membranes of rat testis. The tumor cells, which grow as solid masses in vivo with little organization, undergo organogenesis in vitro into distinct duct-like structures with lumina in the presence of basement membrane scaffoldings. These duct-like structures were formed by flattened epithelial cells, which exhibited poorly differentiated acinar cell characteristics with few or no zymogen (secretory) granules. The cells lining the duct-like structures retained the pancreatic acinar cell specific antigen as determined by indirect immunofluorescence. DNA synthesis did not accompany duct-like organization; however, all of the cells lining these structures continued to incorporate [3H]leucine for up to 4-5 days of culture. They continued to synthesize and secrete amylase, a marker protein of pancreatic acinar cells, into the medium. These results demonstrate that neoplastic epithelial cells of Longnecker pancreatic tumor differentiate into duct-like structures when they come into contact with a basement membrane scaffolding and do not accumulate well-formed secretory granules. This is in marked contrast to the previously reported in vitro differentiation of cells derived from another transplantable rat pancreatic acinar cell carcinoma where the neoplastic cells were fully cytodifferentiated on seminiferous tubular basement membrane without forming duct-like structures but accumulated abundant well-developed zymogen granules (Watanabe et al., Cancer Res., 44: 5361-5366, 1984). Although the basal lamina promotes differentiation of cells of two different pancreatic carcinomas in vitro, we conclude that the in vitro expression of morphogenetic and cytodifferentiation patterns is dependent upon the intrinsic properties of cells of these two transplantable pancreatic tumors.

Lack of clastogenic effects of irradiated glucose in somatic and germ cells of mice

The clastogenic ability of irradiated glucose was evaluated using the micronucleus test in bone marrow cells and the chromosomal aberration assay in the spermatogonial cells of mice. Glucose was irradiated with 0.2, 2.0, 20 and 50 kGy of gamma-rays and administered to mice for various periods. No evidence of mutagenic effects was observed in somatic or germ cells.

Physicochemical properties of oilseed proteins

This review attempts to consolidate the information on the physicochemical properties of proteins from groundnut, soybean, sesame seed, mustard seed, rapeseed, sunflower seed, cottonseed, and other oilseeds. It deals with the extraction and characterization of the oilseed proteins and describes the methods for isolation of the various protein fractions and determination of their physicochemical characteristics. Also discussed are the subunit composition of the oligomeric proteins, their hydrodynamic properties, and the effect of denaturants on these proteins. The similarity in the properties of the proteins from various oilseed materials is discussed. The review article aims to indicate the gaps in our knowledge about the physicochemical properties of oilseed proteins and suggests areas for future investigation.

Circadian desynchronization in pulse rate, systolic and diastolic blood pressure, rectal temperature and urine output in traumatic tetraplegics

An investigation was undertaken to study the circadian rhythmicity in pulse rate, systolic and diastolic blood pressure, rectal temperature and urine output in eight traumatic tetraplegics in view of the fact that diurnal rhythmicity in prolactin response to thyrotropin-releasing hormone was absent in such patients. The data, analysed by single cosinor procedure, showed absence of rhythmicity in all five parameters. Analysis of variance also showed no significant difference in these parameters at various time points. Knowledge of the alterations in circadian biology subsequent to cervical spinal cord trauma would provide useful guidelines towards chronotherapy and vocational rehabilitation of tetraplegics besides possible restoration of euchronism by pharmacological means.

Carcinogenic effect of N-nitrosobis (2-oxopropyl)amine in newborn rats

N-nitrosobis(2-oxopropyl)amine (BOP) was administered twice weekly for a total of 11 doses to 2-day-old Fischer F-344 rats of both sexes to ascertain the spectrum of tissues sensitive to its carcinogenic effects. At 26 weeks, the following incidence of neoplasms were encountered in male and females, respectively; hepatocellular carcinoma (53 and 46%); nephroblastoma (21 and 11%); and in males gonadal stromal tumors of testis (68%). Although acidophilic and basophilic acinar cell foci were encountered in pancreas, these were few in number and microscopic. These findings indicate that in newborn Fischer rats, hepatocytes, epithelial and mesenchymal cells of the kidney, and mesenchymal cells of testis are more sensitive to BOP than those of exocrine pancreas.

Intravesical irrigation with alum for the control of massive bladder hemorrhage

Continuous vesical irrigation with 1 per cent alum solution was performed without anesthesia in 9 patients in whom massive bladder hemorrhage persisted despite evacuation of clots and normal saline irrigation for at least 24 hours. Hematuria ceased promptly in all patients, although the effect was transient in 3. No side effect was observed. Biopsy of the tumor subsequent to alum irrigation showed no alteration in the histological characteristics. Biopsy of the normal-appearing bladder mucosa also showed no evidence of epithelial damage. Ultrastructure of the tumor in 1 patient in whom transurethral resection was performed 2 weeks after alum irrigation revealed well preserved nuclear chromatin, thus, suggesting that whatever changes occur after alum irrigation are short-lived.

Prostaglandins and their precursors can modify genetic damage-induced by gamma-radiation and benzo(a)pyrene

Experiments were performed to study the effect of various prostaglandins (PGs) and their precursors, gamma-linolenic acid (GLA) and arachidonic acid (AA) on gamma-radiation and benzo (a) pyrene (BP)-induced genetic damage to the bone marrow cells of mice, using the sensitive micronucleus (MN) test. Thromboxane B2 prostaglandin E1 and GLA completely prevented BP-induced and reduced to a great degree radiation-induced genetic damage, where as PGE2, PGF2 alpha and AA were without any effect. Since GLA and AA are widely distributed in the cell membranes, and as PGs can be formed virtually in response to any type of stimulus, it is likely that GLA and PGE1 may function as endogenous anti-mutagenic chemicals.

Spectroscopic study of the interaction of gossypol with bovine serum albumin

The interaction of gossypol with bovine serum albumin (BSA) at pH 7.6 in 0.02 M borax-borate buffer has been followed by circular dichroism (CD) and difference spectroscopy. From the extrinsic CD band at 390 nm, a binding constant of 2.7 X 10(3) M-1 was calculated. At 54 degrees the induced CD spectrum was abolished, suggesting that the interaction is not favoured at that temperature. The effect of various solvents and salts on the interaction has been followed by difference spectroscopy. The modification of epsilon-amino groups of lysine did not affect the interaction. Binding of gossypol to BSA does not cause a change in its secondary structure or sedimentation coefficient.

Lack of mutagenicity of irradiated glucose in Salmonella typhimurium using host-mediated assay

Experiments were conducted to study the ability of irradiated glucose to induce reverse mutations in S. typhimurium by host-mediated assay. The results revealed no significant increase in the frequency of reverse mutations compared to controls.