Rat adrenocortical carcinoma 494: an integrated structural, stereological, and biochemical analysis

Snell adrenocortical tumor 494 was implanted into male Sprague-Dawley rats and recovered 7, 14, 21, 28 or 35 days following initial detection by palpation (7-10 days following transplantation). Electron microscopic, stereological and biochemical analyses of the tumor were compared to adrenals of normal animals to serve as a baseline for further studies of the effects of chemotherapeutic agents on tumor cells. Tumor cells possessed oval or elongated mitochondrial profiles with tubular cristae, one or two very large (greater than 5 micrometer) lipid droplets, abundant ribosomes and coated vesicles, and sparse rough and smooth endoplasmic reticulum. Stereologic evaluation revealed that tumor lipid volume was 41% and mitochondrial volume 29% that of the normal adrenal controls. Tumor nuclei were 2.5 times larger than adrenocortical nuclei while cellular volumes were similar. On a net weight basis, tumor cholesterol was 55%, cholesterol ester 2.2%, and lipid phosphate 25% of respective mean values for normal adrenal glands. The tumor cholesterol: cholesterol ester ratio progressively decreased with time but remained 18-fold greater than the normal adrenal. Plasma corticosterone levels in tumor-bearing rats were elevated 3-fold by 14 days and initial detection. The adrenals of the tumor-bearing host exhibited marked involution, the extent of which was directly related to tumor size.     

Comparative studies on the effects of aminoglutethimide on hamster and rat adrenal cortex.

Adult female, intact or steroid suppressed hamsters were treated twice daily with 7 mg aminoglutethimide phosphate (AG) for 5 days while intact female rats received 14 mg AG per injection. AG resulted in an increase in adrenal gland weight of both hamster and rat. In the hamster AG had no effect on the amount of lipid droplets while in the rat a slightly higher number of fine lipid vacuoles was seen. In the hamster, enlargement of the gland was due to hyperplasia of the zona reticularis cells while in the rat the number of glomerulosa and fasciculata cells increased. AG had no effect on the adrenal cortex of steroid suppressed hamsters. The serum cortisol level was markedly higher in AG-treated hamsters while the corticosterone level was notably lower in AG-administered rats. In both hamsters and rats, AG-treatment did not change the serum ACTH level. Thus the study demonstrated different responses of the hamster and rat adrenal cortex to AG.     

Cytokeratin expression in adrenocortical neoplasia: an immunohistochemical and biochemical study with implications for the differential diagnosis of adrenocortical, hepatocellular, and renal cell carcinoma.

The immunostaining patterns of adrenocortical tumors are not clearly defined, primarily due to their inconsistent expression of cytokeratins (CK). To address this issue and to investigate whether adrenocortical tumors can be immunohistochemically differentiated from histologically similar tumors arising from the kidney and liver, we studied four normal adrenal glands, two adrenocortical adenomas (ACAs), 31 adrenocortical carcinomas (ACCs), 37 renal cell carcinomas (RCCs), and 33 hepatocellular carcinomas (HCCs) with anti-CK antibodies AE1, CAM 5.2, UCD/PR10.11, 35BH11, PKK1, and Ks19.1, as well as antibodies to vimentin (VIM), epithelial membrane antigen (EMA), and HMFG-2. Normal adrenal cortical cells showed variable staining with all anti-CK antibodies on fixed and frozen sections. In contrast, only one of two fixed ACAs stained with a single anti-CK, although both neoplasms reacted with multiple anti-CK antibodies on frozen sections. Similarly, 20 of 31 fixed ACCs contained VIM, but only one tumor stained for CK; frozen sections of this and another, previously negative tumor, however, stained with most of the anti-CK antibodies tested. One-dimensional Western immunoblot analysis confirmed the presence of CKs 18 and 19 in two examples of normal adrenal cortex, one ACA, and the ACC immunohistochemically positive on fixed and frozen sections, with CK 19 identified in the ACC that was positive on frozen section alone. All fixed HCCs and most RCCs stained with multiple anti-CK antibodies (33 and 34 cases, respectively), with a proportion of tumors positive for VIM (six and 22 cases, respectively), EMA (seven and 30 cases, respectively), and HMFG-2 (15 and 28 cases, respectively). The results suggest that CK expression is diminished in most adrenocortical tumors to levels too low to be recognized following the deleterious effects of fixation. While the immunohistochemical absence of CK, EMA, and HMFG-2 in fixed sections in the majority of ACCs is distinctive, sufficient phenotypic overlap exists such that differentiation between RCC and HCC may not be possible in an individual case.     

Morphological and biochemical effects of carbon disulfide on rat liver

The early biochemical and ultrastructural effects on the liver of CS₂ administration in vivo to fasted rats were compared in animals treated and not treated with phenobarbital, to ascertain whether these effects differed quantitatively and/or qualitatively. Ultrastructural examination showed that in phenobarbital-treated rats, the main lesion induced by CS₂ was an increase in the number and size of the lysosomes containing cell debris from other cell organelles such as mitochondria. The endoplasmic reticulum was unchanged compared to that of rats treated only with phenobarbital. In particular, there was no decrease in the rough endoplasmic reticulum. By contrast, in rats not treated with phenobarbital, the main effect of CS₂ was a decrease in the number of ribosomes bound to the rough endoplasmic reticulum, with little or no change in other cell organelles. Cytochrome P-450 decreased more in phenobarbital-treated than in untreated rats, and cytochrome b5 decreased in phenobarbital-treated rats only. CS₂ lowered aniline hydroxylase activity, expressed per nanomole of cytochrome P-450 in untreated rats, but increased this activity in phenobarbital-treated rats. The opposite was observed for microsomal peroxidase and cytosolic glutathione reductase activities. Liver catalase diminished more in phenobarbital-treated than in untreated rats. The effects of CS₂ on liver endoplasmic reticulum as well as on the respective activities of aniline hydroxylase, microsomal peroxidase, and glutathione peroxidase show that untreated and phenobarbital-treated rats respond to CS₂ administration in qualitatively different ways. It is suggested that in untreated rats, the effects observed are mainly due to CS₂ itself, whereas in phenobarbital-treated animals, the effects are mainly caused by reactive CS₂ metabolites formed by the mixed function oxidase microsomal system.     

Subcutaneous undifferentiated sarcoma induced by N′-ethyl-N′-nitrosourea in rat: radiology, histopathology and mutagenesis

The aim of the present study was to investigate high dose and long-term effects of a common industrial agent, N'-ethyl-N'-nitrosourea (ENU), on soft tissues in a rat model. ENU, which was dissolved in polyethyleneglycol (PEG) was injected intra-peritoneally once a week (300 mg/kg) in the first experimental group. The second group received only PEG. The control group was free of any agent administration. Only rats treated with ENU for a period of 45 weeks developed large subcutaneous tumours (approximately 5-9 cm in size). Tumoral tissues were examined radiologically, histopathologically and immunohistochemically. There was no bone destruction beneath the soft tumoral tissues in direct X radiograms. Computed tomographic (CT) images showed heterogeneous soft tissue masses with a density ranging from 50 to 65 HU. Macroscopically, all tumors were circumscribed with a gray-white surface in the cross-sections. The histopathological and immunohistochemical examination of the subcutaneous tumoral tissues showed a spindle cell type of sarcoma. Lymphatic and skeletal muscle invasion, atypical mitoses and necroses were determined in all tumoral tissues in the experimental group. A somatic point mutation was detected in exon 2 of KRAS oncogene in sarcoma tissues using the single strand conformational polymorphism (SSCP) analysis. In conclusion, the activated KRAS oncogene might contribute to the progression of subcutaneous sarcoma in experimentally ENU induced rats due to point mutation.     

Early and delayed biochemical effects of paraquat toxicity on rat lung

This research was undertaken to study the early and delayed biochemical effects of paraquat dichloride on the lungs of rats. To accomplish this, female rats were given a sublethal dose (18 mg/kg) of paraquat, in a single (ip) injection. At the end of 24 hr, only catalase, β-N-acetylglucosaminidase, and glucose-6-phosphate dehydrogenase (G6PD) activities and nonprotein sulfhydryl (NPSH) levels were significantly (P < 0.05) increased above saline (0.9%) -injected controls. However, at 6 days after paraquat injection, all biochemical indices measured were significantly (P < 0.02) above those values of controls. These findings indicate that the biochemical changes produced by paraquat might be consistent with the changes in the population of cell types, which are well documented histologically by other investigators.     

Effect of o,p'-dichlorodiphenyldichloroethane on glutathione reductase activity and content of SH groups in the dog adrenals.

The effect of o, p'-dichlorodiphenyldichloroethane (DDD), a compound inducing atrophy of the adrenal cortex and blocking steroid production, on glutathione reductase activity was studied. As a result of feeding dogs with DDD in a dose of 50 mg/kg body weight for 14 days activation of glutathione reducatase took place in the homogenate, cytoplasmic fraction, and disintergrated mitochondria of the adrenals. On the additon of DDD in vitro the activity of the enzyme was unchanged. The content of SH groups expressed per 100 mg tissue was reduced in the homogenate and in all subcellular fractions. If expressed per 100 mg protein in the level of SH groups was lowered only in the microsomes and the disintergrated mitochondria.     

Synergistic genotoxicity caused by low concentration of titanium dioxide nanoparticles and p,p′‐DDT in human hepatocytes

The use of titanium dioxide nanoparticles (nano‐TiO₂) for the degradation of dichlorodiphenyltrichloroethane (p,p′‐DDT) increases the risk of exposure to trace nano‐TiO₂ and p,p′‐DDT mixtures. The interaction of p,p′‐DDT and nano‐TiO₂ at low concentrations may alter toxic response relative to nano‐TiO₂ or p,p′‐DDT alone. In this work, the combined genotoxicity of trace nano‐TiO₂ and p,p′‐DDT on human embryo L‐02 hepatocytes without photoactivation was studied. Nano‐TiO₂ (0.1 g/L) was mixed with 0.01–1 mmol/L p,p′‐DDT to determine adsorption isotherms. L‐02 cells were exposed to different levels of p,p′‐DDT (0, 0.001, 0.01, and 0.1 μmol/L) and nano‐TiO₂ (0, 0.01, 0.1, and 1 μg/mL) respectively. The adsorption of p,p′‐DDT by nano‐TiO₂ was approximately 0.3 mmol/g. Cell viability, apoptosis, and DNA double strand breaks were similar among all test groups. Nano‐TiO₂ alone (0.01–1 μg/mL) increased the levels of oxidative stress and oxidative DNA adducts (8‐OHdG), but it did not induce DNA breaks or chromosome damage. Addition of trace nano‐TiO₂ with trace p,p′‐DDT synergistically enhanced genotoxicity via increasing oxidative stress, oxidative DNA adducts, DNA breaks, and chromosome damage in L‐02 cells. Low concentrations of nano‐TiO₂ and p,p′‐DDT increased oxidativestress by reactive oxygen species (ROS) formation and lipid oxidation. Oxidative stress is a major pathway for DNA and chromosome damage. Dose‐dependent synergistic genotoxicity induced by combined exposure of trace p,p′‐DDT and nano‐TiO₂ suggests a potential environmental risk of nano‐TiO₂ assisted photocatalysis. Environ. Mol. Mutagen., 2010. © 2009 Wiley‐Liss, Inc.     

Aversive prenatal stimulation: effects on behavioral, biochemical, and somatic ontogeny in the rat.

Electric foot shock administered to pregnant rats altered the ontogeny of spontaneous motor activity in their pups. Prenatally stimulated (PMS) offspring were more active than controls on Days 1-10 but less active during the 3rd postpartum week. The age of peak activity, a major developmental landmark, occurred in PMS pups around 10 days of age; in controls maximum activity was not seen until the 3rd week. This effect was independent of the gender of the offspring and the timing of the gestational stimulation. Its appearance in both cross-fostered and fostered pups indicated the prenatal origin of the effect. The maturation of spontaneous alternation behavior and several reflexes and the appearance of physical features were not affected by prenatal stimulation. Moreover, both PMS and control groups exhibited an age-related increase in brain concentrations of norepinephrine, serotonin, and 5-hydroxyindoleacetic acid. These findings indicate that spontaneous motor activity is uniquely sensitive to PMS, and as far as can be determined here, PMS produces no generalized alteration in behavioral and physical ontogeny.     

Effect of o,p-dichlorodiphenyldichloroethane and perthane in vitro on glutathione reductase activity in the adrenals of dogs and guinea pigs

o,p-Dichlorodiphenyldichloroethane (o,p-DDD) and Perthane, when added in a concentration of 312 M to homogenate and cytoplasmic fraction of dog adrenals, activate glutathione reductase. In a concentration of 156 M, o,p-DDD and Perthane do not affect glutathione reductase activity of the dog adrenals. When given in vitro, o,p-DDD and Perthane activate glutathione reductase of the guinea pig adrenals. o,p-DDD has no effect on glutathione reductase activity of the cytoplasmic fraction of dog liver and kidney, thus confirming the high specificity of its effect on the adrenal cortex.Laboratory of Pathophysiology, Institute of Endocrinology and Metabolism, Kiev. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 159–161, February, 1978.     

Synthesis and properties of fluorinated polyimides, 2. Derived from novel 2,6‐bis(3′‐trifluoromethyl‐p‐aminobiphenyl ether)pyridine and 2,5‐bis(3′‐trifluoromethyl‐p‐aminobiphenyl ether)thiophene

Novel diamine monomers, 2,6‐bis(3′‐trifluoromethyl‐p‐aminobiphenyl ether)pyridine (TABP) and 2,5‐bis(3′‐trifluoromethyl‐p‐aminobiphenyl ether)thiophene (TABT) have been synthesized, which lead to a number of novel fluorinated polyimides by thermal imidization routes when reacted with different commercially available dianhydrides like pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA) or 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides ABTP/6FDA and ABTT/6FDA are soluble in several organic solvents such as N,N‐dimethylformamide (DMF), N,N‐dimethylacetamide (DMAc) and tetrahydrofuran (THF). The polyimide ABTP/PMDA is only soluble in N‐methylpyrollidone (NMP) whereas ABTT/PMDA is insoluble in all solvents. The polyimides ABTP/6FDA (2c) and ABTT/6FDA (3c) exhibited number‐average molecular weight 32 940 (polydispersity index (PDI), 1.97) and 24 760 (PDI, 1.87) respectively. These polyimide films have low water absorption rate 0.3–0.9% and low dielectric constant 2.92–3.29 at 1 MHz. These polyimides showed very high thermal stability even up to 532 °C for 5% weight loss in synthetic air and glass transition temperature up to 287 °C (by DSC) in nitrogen. All polyimides formed tough transparent films, with tensile strength up to 115 MPa, a modulus of elasticity up to 2.91 GPa and elongation at break up to 12% depending upon the exact repeating unit structure.

TGA thermograms of the thiophene ring poly(ether imide)s.     

Synchrotron X‐ray and DSC Studies of the Phase Behaviour of Poly(diethylene glycol p,p′‐bibenzoate)

Time‐resolved synchrotron X‐ray and DSC experiments were applied to investigate the phase behaviour of poly(diethylene glycol p,p′‐bibenzoate), PDEB. The DSC results are indicative of the formation of a smectic mesophase, previously identified as a SmCA type, which can be easily quenched down to room temperature. However, the synchrotron results show that the SmCA phase undergoes some kind of ordering or transformation at temperatures below 110 °C. Moreover, the annealing of PDEB at temperatures above T_g for sufficiently long times leads to the formation of a highly ordered structure, although very thin crystals and low crystallinities are obtained.

Scattering profiles corresponding to sample PDEB85 in a melting experiment.     

Effect of o,p′-dichlorodiphenyldichloroethane on gluta thione reductase activity and content of sh groups in the dog adrenals

The effect of o,p′-dichlorodiphenyldichloroethane (DDD), a compound inducing atrophy of the adrenal coretx and blocking steroid production, on glutathione reductase activity was studied. As a result of feeding dogs with DDD in a dose of 50 mg/kg body weight for 14 days activation of glutathione reductase took place in the homogenate, cytoplasmic fraction, and disintegrated mitochondria of the adrenals. On the addition of DDD in vitro the activity of the enzyme was unchanged. The content of SH groups expressed per 100 mg tissue was reduced in the homogenate and in all subcellular fractions. If expressed per 100 mg protein the level of SH groups was lowered only in the microsomes and the disintegrated mitochondria.