Hematological toxicity associated with tissue extract from poisonous fish Lagocephalus lagocephalus--influence on erythrocyte function in Wistar rats.

The puffer fish Lagocephalus lagocephalus represents serious public health problems in the world. The relative toxicity of each organ (liver and flesh) was determined by the relation dose-death time "mouse bioassay." The average liver toxicity of the puffer fish was the highest when compared with flesh giving 14.32 and 10.88 MU/g, respectively. A mouse unit is the amount of toxin (extract of fish organ) that kills a 20 g male mouse in 30 min after intraperitoneal injection. One mouse unit is equivalent to 0.22 microg of TTX. For the rat bioassay tests, Wistar rats were daily i.p. injected, for 10 d, with extracts of liver (LT) or flesh (FT) (muscles + skin) of L. lagocephalus. Control rats received injection of NaCl (0.9%). During the experiment, a significant reduction in red blood cell number (RBC), hemoglobin (HGB) concentration, and hematocrit (HCT) was observed essentially after 10 d of treatment in the FT and LT-exposed groups. Consequently, treatment led to severe anemia and hemolytic action as indicated by a significant reduction in the total number of erythrocytes. In fact, our study revealed a significant increase in erythrocyte lipid peroxidation (LPO) in FT and LT groups compared with controls after experimental exposure. The flesh and liver tissue extracts also altered antioxidative enzymes activities: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Histopathological alterations in the spleen occurred exclusively at the end of treatment. We marked also an increase in reticulo-endothelial cells, which led to remove damaged erythrocytes.

Effects of liver-supplemented food on the development of embryos in mice.

We examined whether dietary intake of cattle liver-supplemented food induces reproductive effects in dams and developmental effects in embryos in the mouse model. Seven groups of 19 to 35 female mice each were given either powdered food or the food supplemented with crude liver homogenate, its lipophilic component, the defatted liver homogenate or vitamin A (retinol palmitate) during a 25-d period spanning from a week prior to mating to gestation day 18 (GD18). Fetal mortality and incidence of external abnormalities of the fetuses whose dams were given the diet supplemented with the crude liver homogenate increased dose-dependently with an increase in the supplemented amount of the crude liver homogenate. On the other hand, the defatted liver homogenate did not induce any reproductive or teratological effect. The vitamin A (VA)-supplemented food (950 IU/5 g food as VA) induced approximately the same levels of the incidence of total external abnormalities appearing at the same affected regions or organs as the foods supplemented with the 700 mg crude liver homogenate (1029 IU/5 g food as VA) and its lipophilic component (950 IU/5 g food as VA). The content of VA (as 1029 IU/5 g food) in the crude liver homogenate was found to be approximately equal to that in the lipophilic component (950 IU/5 g food as VA). Therefore, it was concluded that VA plays an important role in induction of the lethal and teratogenic effects in the fetuses whose dams were given the powdered foods supplemented with the crude liver homogenate and its lipophilic component.

Base-substitution profiles of externally activated polycyclic aromatic hydrocarbons and aromatic amines determined in a lacZ reversion assay.

Using an improved set of lactose-auxotrophic Escherichia coli tester strains, the proportion of the six possible transitions and transversions after mutagen exposure was assessed. Mutagenic specificity was determined in plate-incorporation assays using lactose-containing minimal medium for the selection of revertants, either after application of directly acting mutagens or by including a metabolic activation system with rat liver S9-extract. The differential and dose-dependent response of the six tester strains was shown by treating the bacteria with described diagnostic mutagens and other directly DNA damaging substances, e.g., N-methyl-N-nitrosoguanidine (MNNG) and benzo[a]pyrene-diolepoxide (BPDE). Polycyclic aromatic hydrocarbons and aromatic amines were investigated in the presence of an external metabolic activation system. Benzo[a]pyrene (BaP) yielded similar mutation profiles as its ultimate mutagen BPDE, if 100-fold increased doses were applied. In contrast to the mutation profile of BaP, which was dominated by G:C-T:A transversions, mutagenesis with benzo[c]phenanthrene (BcPh) produced predominantly A:T-T:A transversions. The same base change was observed with 5-methylchrysene and found to be missing with 5,6-dimethylchrysene, while both compounds caused G:C-A:T transitions. The aromatic amines 4-aminobiphenyl (4-ABP), 2-aminoanthracene (2-AA) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhlP) yielded similar yet distinguishable mutation profiles. Base-substitution reversion profiles of the chemical mutagens were in agreement with those obtained in other systems and with molecular analysis of mutants induced by these agents.

A comparison of mutational specificity of mutations induced by S9-activated B[a]P and benzo[a]pyrene-7,8-diol-9,10-epoxide at the endogenous aprt gene in CHO cells.

We have determined the mutational specificity of S9-activated benzo[a]pyrene (B[a]P) at the endogenous aprt locus in a hemizygous Chinese hamster ovary cell line. The aprt gene of recovered mutants was amplified using the polymerase chain reaction (PCR) and directly sequenced. This spectrum was then compared to mutations recovered following treatment with the B[a]P metabolite, benzo[a]pyrene diol-epoxide (BPDE). No significant difference between the two spectra in the types of mutations produced, or their distribution was observed. This observation supports the hypothesis that BPDE is the reactive metabolite of B[a]P, responsible for the significant biological effects caused by this ubiquitous polycyclic aromatic hydrocarbon. The major mutation recovered was the G:C-->T:A transversion, and mutations were primarily localized within runs of guanines. We also confirmed our previous finding that mutation by B[a]P is non-random, targeting events in runs of guanines flanked by adenine residues. This same target hotspot region is found in codon 61 of the human c-Ha-ras1 proto-oncogene. This may help explain the selective activation of this codon by BPDE.

Potential in vitro activity of Kutapressin against Epstein-Barr virus.

BACKGROUND: Kutapressin (KU), a porcine liver extract with bradykinin-potentiating effects but no vitamin B 12 activity, has been used in the treatment of Herpes zoster. We examined a phenol-free preparation of this drug for in vitro activity against Epstein-Barr Virus (EBV). MATERIALS AND METHODS: Immortalization-inhibition assays were used to assess EBV infectivity. Mitogen stimulation and cell viability assays were used to assess kutapression toxicity. Lytic replication assays and flow cytometry were used to assess the mechanism of drug activity. RESULTS: Seventy-five hundred mcg/ml of KU blocked the infection of 2 x 10(5) human umbilical cord mononuclear cells when added together with two strains of EBV (B95-8 and FF41). Doses as low as 250 mcg/ml were occasionally effective as well. Unlike acyclovir, KU does not inhibit viral DNA polymerase nor does it appear to compete with EBV as it binds to its receptor on the B-cell surface. CONCLUSIONS: The mechanism whereby KU may inhibit EBV immortalization remains to be determined. KU, a drug which is safe in humans, deserves further study as an agent with potential to block EBV-induced immortalization of B-lymphocytes.

Metabolic activation in the fetal mouse salivary gland culture system with rat hepatocytes, rat S-9, and human S-9.

The usefulness of an in vitro assay for embryotoxicity may depend on the availability of metabolic activation systems that will function in the culture system. The fetal mouse salivary gland has been investigated as an in vitro assay system. To see if the glands would grow in the presence of metabolic activators and if the glands would react to metabolites known to be embryotoxic, the glands were grown in the presence of cyclophosphamide (CP) and several activation systems. These included isolated rat hepatocytes, uninduced rat S-9, rat S-9 induced with 3-methylcholanthrene (3-MC), rat S-9 induced with Aroclor 1254, and human S-9. Twenty salivary glands were isolated from 13 day embryos (plug day = 0) and were grown in each treatment for 48 h. One control had no activation system of CP, one had an activation system but no CP, and three treatments had the activation system and 25, 75, or 150 micrograms/ml CP. The S-9 with cofactors and the appropriate amount of CP was contained in dialysis bags. The greatest suppression of salivary gland growth occurred in co-culture with hepatocytes activating CP. The S-9 induced by Aroclor 1254 was nearly as effective as the hepatocytes. The next most effective was a group with similar activity consisting of the uninduced rat S-9 and the three samples of human S-9. The 3-MC-induced S-9 was the least effective in suppressing growth of salivary glands. All the activation systems tested can be used with the salivary gland culture system.

Precipitable tissue proteins can cause experimental acute renal failure.

UNLABELLED: A previous investigation demonstrated that intravenous infusion of a saline-liver extract into rats causes acute renal failure (ARF), manifested by severe azotemia, extensive cast formation, and patchy tubular necrosis. The purpose of the present study was to explore its pathogenesis. Histologic assessments of rat kidneys made 1.5 hours after liver extract infusion demonstrated eosinophilic material within glomerular capillaries, Bowman's space, and proximal tubular lumina, distal nephron cast formation, and tubular dilation without evidence of tubular necrosis. Renal blood flow at this time was normal but the rats were anuric. Assessments made 24 hours after liver extract infusion demonstrated persisting ARF (blood urea nitrogen, 132 +/- 8; creatinine, 2.54 +/- 0.19 mg/dl), profound cast deposition almost exclusively in the inner medulla/papilla, and the appearance of patchy proximal tubular necrosis. Sephacryl S200 fractionation and 10% polyacrylamide gel electrophoresis of liver extract showed high and low molecular weight proteins (less than 30,000). Proteins in both regions demonstrated prominent acid precipitability (pH 4.5) and autoaggregation (at 37 degrees C). Trace amounts of spontaneously precipitated protein recovered from urine during liver extract infusion demonstrated a predominance of low molecular weight proteins by polyacrylamide gel electrophoresis. Infusing rats with filterable low molecular weight proteins (cytochrome c, ribonuclease, myoglobin) without autoaggregation/acid precipitation characteristics or liver extract made devoid of precipitable proteins failed to induce ARF. However, infusing a kidney extract containing acid precipitating/autoaggregating proteins caused inner medullary/papillary cast formation and ARF. CONCLUSION: normal parenchymal tissues contain proteins which can undergo glomerular filtration and which can spontaneously aggregate under conditions which exist in the distal nephron. If released into the circulation, or if shed from tubular cells into lumina after nephrotoxic or ischemic renal injury, they could help to induce intratubular obstruction and ARF.

[Study of the toxic factor in liver extracts]. / Izuchenie toksicheskogo faktora pechenochnykh ékstraktov.

Dissolution of mitochondrial fraction of ischemic liver was carried out using various detergents, the most effective of which was sodium dodecylsulphate (SDS). Excess of SDS was removed by dialysis or by sorption on anion exchange resin. The optically homogenous solution obtained was subsequently purified by gel filtration on Sephadex G-75. The preparation contained two fractions: the molecular weight of the major fraction corresponded to that of gamma-globulin and the molecular weight of the minor fraction--to that of cytochrome C. Interrelation was observed between the toxic activity and hydrophobic components of the fraction isolated.

Properties of hepatic tissue extracts: 2. An approach to the artificial liver.

In the previous paper [3], the lethal effect of normal rabbit liver extract intravenously infused into rabbits was described. By comparing to the course of destruction of the liver tissue in fulminant hepatitis, the toxicity of the liver extract was recently studied. Attempts were also made to adsorbing the liver extract by activated clay and detoxifying the liver extract with a formaldehyde solution, and the results suggested that the findings would be applicable as an approach to the artificial liver.