Glutaraldehyde-treated homologous vein graft as a vein substitute: experimental study in rabbits.

AIM: Vein reconstruction using grafts may prevent sequelae of venous interruption or lesion. Autologous vein is sometimes unsuitable or absent for a vascular restoration. The aim of this study was to study glutaraldehyde-treated homologous vein graft as vein substitute and compare it with autologous vein as a substitute for a vena cava segment in rabbits. METHODS: Sixty rabbits were allocated into two groups: autologous vein graft (AG), and glutaraldehyde-treated homologous vein graft (HG). Each group was subdivided into three subgroups (N.=10) to be studied at: 24 hours, 14 days, and 28 days. The veins were treated in 0.19% glutaraldehyde, pH=7.4, for 1 hour and kept at 4 degrees C in saline with added gentamicin and amphotericin B. The animals received benzanthine penicillin on the day of graft implantation and heparin only during surgery. The grafts were implanted into the vena cava. Anastomosis was performed with interrupted sutures. Cavography was performed, after surgery, and at the time the animals were killed. Evaluation of the veins was made macroscopically and by light and scanning electron microscopy. RESULTS: Fibrosis was seen around the grafts at 14 and 28 days, with no difference in intensity between the groups. Cavography performed before euthanasia of the animals showed 4 partial thrombi in AG (2 at 24 hours and 2 at 14 days), 3 in HG (2 at 24 hours and 1 on day 14), and 4 occlusive thombi in HG (3 at 14 days and 1 at 28 days). Macroscopic examination did not show any thrombus in AG. In HG, two partial thrombi were confirmed at 24 hours and three occlusive thrombi at 14 days. There was no statistical difference in relation to patency between the two groups. At 14 and 28 days, the histological sections showed intimal hyperplasia of similar intensity and variable distribution in both groups. Evaluation by electron microscopy showed at 24 hours lesion areas characterized by absence of the endothelium on the graft surface, presence of inflammatory cells, and, at some sites, presence of mural thrombi in AG and HG. Both groups at 14 and 28 days showed endothelial cells covering the lesion area on the graft surface, this covering being larger in AG than in HG. CONCLUSIONS: In the studied model, both grafts behaved similarly in relation to patency and morphological characteristics. This suggests that the glutaraldehyde-treated graft can be a promising alternative for vein reconstruction, justifying further animal studies with the aim of using it in human surgery.

Prevalence of deep vein thrombosis and pulmonary embolism in superficial thrombophlebitis of the lower limbs: prospective study of 60 cases.

AIM: Superficial thrombophlebitis (ST) ascending the lower limbs is a common disease, which may be associated with deep vein thrombosis (DVT) and pulmonary embolism (PE). The aim of this study was to investigate the prevalence of DVT and PE as complications of ascending ST of the lower limbs in the great saphenous vein (GSV) or SSV (SSV) and probable risk factors. METHODS: For this study 60 consecutive patients were enrolled with ascending ST of the GSV or SSV, seen between 2000 and 2003 at a public hospital in Botucatu, SP, Brazil. All patients were assessed clinically, by venous Duplex scanning of the lower limbs to confirm ST and test for DVT, and by means of pulmonary scintigraphy to test for PE. RESULTS: In 13 ST cases (21.67%) there was concomitant DVT and 17 ST patients (28.33%) also had PE. Eleven patients had a clinical status suggestive of DVT, but only in eight of these (61.5%), this clinical diagnosis was confirmed. Fourteen patients had a clinical status suggestive of PE, and this diagnosis was confirmed in six cases (35.30%). ST patients who also had DVT and/or PE were given anticoagulant treatment with heparin and warfarin. None of the variables studied was predictive of DVT or PE (P>0.05). However, the presence of varicose veins reduced the risk of patients having DVT (relative risk=9.09; 95%CI:1.75 - 50.00 and P=0.023). CONCLUSIONS: The prevalence rates of PE (28.3%) and DVT (21.6%) were elevated in this sample of ascending ST cases, indicating a need for detailed assessment of patients for signs of these complications, including for therapeutic management decision making.

Advances in ultrasound techniques improve early detection of deep vein thrombosis.

AIM: This study aimed at assessing the accuracy of ultrasound (US) in the diagnosis of recent deep vein thrombosis (DVT) in an experimental study in dogs. DESIGN: blinded and randomized experimental study. Twenty dogs were randomly divided in two groups: control group (CG) and thrombosis group (TG). US was performed in the pre- and postoperative period. Phlebography was performed immediately prior to the postoperative US. After the second US, a surgery was performed to detect whether thrombus was present or not. US results were compared to those of phlebography and surgical findings. RESULTS: In all dogs, inferior vena cava (IVC) was compressible. The relations of IVC diameter with the aorta were higher (P<0.005) in TG than in CG. Spectral Doppler in spontaneous breathing, tissue harmonic imaging, power Doppler and B flow showed sensitivity, specificity and accuracy of 1. Phlebography presented sensitivity of 90%, specificity of 80% and accuracy of 85%, when compared to surgical finding. CONCLUSIONS: For the diagnosis of recent DVT in the experimental model used, venous compressibility proved to be inefficient. The ratio of IVC diameter to aorta, when increased, suggests thrombosis. The use of new US technological advances increases accuracy. Phlebography was less accurate than US.

Incorrect use of thromboprophylaxis for venous thromboembolism in medical and surgical patients: results of a multicentric, observational and cross-sectional study in Brazil.

OBJECTIVES: Although effective strategies for the prevention of venous thromboembolism (VTE) are widely available, a significant number of patients still develop VTE because appropriate thromboprophylaxis is not correctly prescribed. We conducted this study to estimate the risk profile for VTE and the employment of adequate thromboprophylaxis procedures in patients admitted to hospitals in the state of São Paulo, Brazil. METHODS: Four hospitals were included in this study. Data on risk factors for VTE and prescription of pharmacological and non-pharmacological thromboprophylaxis were collected from 1454 randomly chosen patients (589 surgical and 865 clinical). Case report forms were filled according to medical and nursing records. Physicians were unaware of the survey. Three risk assessment models were used: American College of Chest Physicians (ACCP) Guidelines, Caprini score, and the International Union of Angiololy Consensus Statement (IUAS). The ACCP score classifies VTE risk in surgical patients and the others classify VTE risk in surgical and clinical patients. Contingency tables were built presenting the joined distribution of the risk score and the prescription of any pharmacological and non-pharmacological thromboprophylaxis (yes or no). RESULTS: According to the Caprini score, 29% of the patients with the highest risk for VTE were not prescribed any thromboprophylaxis. Considering the patients under moderate, high or highest risk who should be receiving prophylaxis, 37% and 29% were not prescribed thromboprophylaxis according to ACCP (surgical patients) and IUAS risk scores, respectively. In contrast, 27% and 42% of the patients at low risk of VTE, according to Caprini and IUAS scores, respectively, had thromboprophylaxis prescribed. CONCLUSION: Despite the existence of several guidelines, this study demonstrates that adequate thromboprophylaxis is not correctly prescribed: high-risk patients are under-treated and low-risk patients are over-treated. This condition must be changed to insure that patients receive adequate treatment for the prevention of thromboembolism.

Levels of antimicrobial molecules defensin and lactoferrin are elevated in the cerebrospinal fluid of children with meningitis.

OBJECTIVE: To measure levels of defensins and lactoferrin in the cerebrospinal fluid (CSF) of children with meningitis. STUDY DESIGN. Prospective descriptive study involving children undergoing lumbar puncture during evaluation for meningitis. METHODS: CSF concentrations of defensins and lactoferrin were determined using enzyme-linked immunosorbent assays on 19 children with bacterial meningitis, 31 children with aseptic meningitis, and 32 control children found to have normal CSF during evaluation for meningitis. Pertinent clinical and laboratory data were gathered on all children. RESULTS: CSF concentrations of both defensins and lactoferrin were elevated markedly in children with bacterial and aseptic meningitis, compared with control children. No control subject had detectable levels of defensins in the CSF. Lactoferrin was undetectable in the CSF of 31 of 32 control subjects. Defensin and lactoferrin levels were significantly higher in the CSF of children with bacterial meningitis than in those with aseptic meningitis. Defensin levels in the CSF of children with bacterial meningitis ranged from 128 ng/mL to 99 430 ng/mL with a mean of 30 311 ng/mL (SD +/- 28 865) and a median of 23 042 ng/mL. Defensin levels in the CSF of children with aseptic meningitis ranged from 0 ng/mL to 1675 ng/mL with a mean of 227 ng/mL (SD +/- 433) and a median of 23 ng/mL. A significant correlation was found between defensin levels in the CSF and the total leukocyte count and the absolute neutrophil count in the CSF of children with bacterial meningitis. Lactoferrin levels in the CSF of children with bacterial meningitis ranged from 184 ng/mL to 31 412 ng/mL with a mean of 13 209 ng/mL (SD +/- 9644) and a median of 10 382 ng/mL. Lactoferrin levels in the CSF of children with aseptic meningitis ranged from 0 ng/mL to 2715 ng/mL with a mean of 1042 ng/mL (SD +/- 878) and a median of 852 ng/mL. No correlation was found between lactoferrin level in the CSF and the total leukocyte count or the absolute neutrophil count in the CSF of children with bacterial meningitis. In our study population, the sum total of CSF defensins and lactoferrin was found to be highly sensitive and specific in delineating bacterial from aseptic meningitis when compared with standard CSF studies. CONCLUSIONS: Significant elevations of defensins and lactoferrin, indicative of endogenous local antimicrobial peptide and polypeptide release, are found in the CSF of children with meningitis. We speculate that elevations in these antimicrobial molecules may reflect the intensity of the host response. Defensins seem to parallel neutrophil activation more closely than lactoferrin. Cumulative levels of CSF defensins and lactoferrin clearly distinguished bacterial meningitis from aseptic meningitis and control patients. Further investigation is warranted to determine the usefulness of measuring defensins and lactoferrin as a diagnostic tool and therapeutic monitor in the evaluation of children with meningitis.

Factor XIII Val34Leu is a genetic factor involved in the etiology of venous thrombosis.

A mutation in the factor XIII gene (FXIII Val34Leu) gene was recently reported to confer protection against myocardial infarction, but its relationship with venous thrombosis is unknown. In addition, a mutation in the 5'-untranslated region of the FXII gene (46 C->T) was identified which is associated with low plasma levels of the protein. Its prevalence in patients with venous thrombosis is also unknown. We investigated the frequency of the FXIII Val34Leu and FXII 46 C->T mutations in 189 patients with deep venous thrombosis and in 187 age-, gender- and race-matched controls. FXIII Val34Leu was detected in 38.6% of the patients and in 41.2% of the controls. Interestingly, homozygosity for the FXIII mutation was found in 1.6% of the patients and in 9.6% of the controls, yielding an odds ratio (OR) for venous thrombosis of 0.16 (95% CI: 0.05-0.5). The OR for heterozygotes was 1.1 (95% CI: 0.7-1.7). The FXII 46 C->T mutation was detected in 46.0% of the patients and in 48.6% of the controls. The OR for heterozygotes was 0.9 (95% CI: 0.6-1.4) and for homozygotes the OR was 0.8 (95% CI: 0.3-1.9). Our data indicate that the FXII 46 C->T mutation is unlikely to be a major risk factor for venous thrombotic disease. In contrast, the homozygous state for FXIII Val34Leu is a strong protective factor against venous thrombosis, which emerges as a novel genetic factor involved in the aetiology of thrombophilia.

Interactive effects between trichloroethylene and pesticides at metabolic and genetic level in mice.

A combined cytogeneticurine metabolite analysis approach was used to assess potential interactive effects between Fenarimol (FN), a fungicide, and trichloroethylene (TRI), a halogenated solvent. FN was demonstrated to selectively induce P450-2B1 isoforms in different organs of treated mice. Since the rate of metabolism and the stereospecificity of metabolism are dependent on the types and amount of P450s available, FN might drastically alter the metabolic activation of a precarcinogen, such as TRI, and its toxicological consequences. Male CD1 mice were divided into untreated, vehicle control, and experimental groups. Animals of the latter groups were treated ip with 150 mg/kg bw FN in corn oil, 457 mg/kg bw TRI in corn oil, TRI plus FN separated by different time intervals. Bone marrow cells were harvested for determination of micronuclei (MN) frequencies in polychromatic erythrocytes (PCE). The presence of the known metabolite of TRI, trichloroethanol (TCE), was quantitated in collected urine by gas chromatography using an electron-capture detector. Linear regression analysis shows that MN frequency by TRI is correlated with TCE concentration in urine. Observed potentiation of genotoxicity of TRI by FN pretreatment (1 hr before TRI treatment) apparently reflects changes in the spectra of enzymes involved in TRI metabolism, and altered toxicokinetic, as witnessed by the 20% difference in TCE excretion from combined treated mice. However, no increased genetic or metabolic effects were observed when FN was administered 3 hr before TRI. No significant interactive effects were observed at a genetic level when FN was administered 1 hr and 3 hr after TRI whereas a 33 to 47% loss in TCE excretion was recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of licorice on glycyrrhizin pharmacokinetics.

The effects of components of aqueous licorice root extract (LE) on the pharmacokinetics of glycyrrhizin (G) and glycyrrhetic acid (GA) were investigated in rats and humans. The aim of this work was to define the role of pharmacokinetics in G toxicity. In the procedure, G and GA were detected in biological fluids by means of recently improved HPLC methods. Significantly lower G and GA plasma levels were found in rats and humans treated with LE compared to the levels obtained with those in which G alone was administered. The pharmacokinetic curves showed significant differences in the areas under the plasma-time curve (AUC), Cmax, and Tmax parameters. The data obtained from urine samples are in agreement with the above results and confirm a reduced bioavailability of G present in LE compared to pure G. This should be attributed to the interaction during intestinal absorption between the G constituent and the several components in LE. The modified bioavailability could explain the various clinical adverse effects resulting from the chronic oral administration of G alone as opposed to LE.

Treatment of shigellosis with cefixime: two days vs. five days.

BACKGROUND: Although the recommended standard course of therapy for shigellosis is 5 days of oral ampicillin or trimethoprim-sulfamethoxazole therapy, successful outcome has been reported in adults treated with abbreviated courses of antibiotics. The purpose of this study was to compare short course (2-day) vs. 5-day therapy with cefixime for treatment of diarrheal disease caused by Shigella sonnei in children. METHODS: This was a prospective, randomized, double blind, placebo-controlled study. Patients were eligible if they were at least 6 months of age and presented to the Children's Hospital of Pittsburgh during an outbreak of diarrhea caused by S. sonnei, with (1) a history of fever and diarrhea (at least three loose or watery stools per day), (2) bloody diarrhea or (3) diarrhea and known exposure to an individual with documented shigellosis. Patients were randomized to receive either 2 days of cefixime (8 mg/kg(day) given once daily followed by 3 days of placebo or 5 days of cefixime. Telephone follow-up was performed on Days 3, 7 and 14 after enrollment. Follow-up stool cultures were obtained on Day 7 to assess bacteriologic cure. There were standardized definitions for cure, improvement, failure and relapse. RESULTS: Forty-seven patients were enrolled. Eleven were eliminated from analysis because their stool cultures were not positive for S. sonnei. There were 36 evaluable patients, 21 in the 2-day group and 15 in the 5-day group. Patients ranged in age from 6 months to 17 years. Forty-four percent of the subjects were male. Symptoms were improved or had resolved by Day 3 of therapy in all patients. There were 8 patients who experienced a clinical relapse: 5 of 21 (24%) patients in the 2-day treatment group and 3 of 15 (20%) in the 5-day group. There were 13 patients who experienced a bacteriologic failure (defined as the occurrence of a positive culture at the Day 7 follow-up visit), 11 of 20 (55%) in the 2-day group and 2 of 14 (14%) in the 5-day group (P < 0.02). CONCLUSION: Two- and 5-day treatment courses with cefixime for treatment of diarrheal disease caused by S. sonnei result in similar rates of clinical cure and clinical relapses; however, there was a higher rate of bacteriologic failure with shorter course therapy.

Varicose veins and chronic venous insufficiency in Brazil: prevalence among 1755 inhabitants of a country town.

The prevalence of varicose veins (VV) and of chronic venous insufficiency (CVI) was studied among 1755 adults over 15 years of age (443 men and 1312 women). These people attended the University Health Center in Botucatu, a country town in the State of Sao Paulo, Brazil, for routine examination or for any disease complaints. The prevalence of all grades of VV not including telangiectasis and reticular varices grade I was 47.6% (37.9% in men and 50.9% in non-pregnant women). The prevalence of VV recorded as moderate or severe was 21.2%. The more severe form of CVI with active or healed ulcer was present in 3.6% of the subjects (2.3% of men and 4% of women). For only 5.5% of the patients was VV or CVI the reason for medical consultation. The prevalence of VV increased with age and number of pregnancies and was greater among white than non-white people. Working posture or posture adopted for defaecation did not influence the prevalence of VV. Our data show the prevalence of VV and CVI to be higher or as high as the prevalence found in developed western countries. We therefore propose that studies of these conditions should be included in epidemiological surveys of other developing areas or countries, so that if data similar to ours are verified prophylaxis and early treatment could be included in health planning for these areas with the aim of reducing future morbidity and the related social onus.

Effect of different glycosaminoglycans in a guinea-pig carotid artery thrombosis model.

Heparin is the most frequently used drug for the prevention and treatment of thrombosis. Its use, however, is restricted by its side-effects. To study the efficacy of other glycosaminoglycans that could substitute heparin in the management of arterial thrombosis, 60 guinea-pigs were randomly allocated into 6 groups: G1 = control, G2 = heparin (150 IU/kg), G3 = heparan sulfate from beef pancreas (2.5 mg/kg), G4 = heparan sulfate from beef lung (2.5 mg/kg), G5 = N-acetylated heparan from beef pancreas, G6 = dermatan sulfate from beef intestine (2.5 mg/kg). Ten minutes after intravenous injection of the drugs, thrombosis was induced by the injection of a 50% glucose solution into a segment of the right carotid artery isolated between 2 thread loops during 10 minutes. Three hours later the artery was re-exposed and if a thrombus was present it was measured, withdrawn and weighed. Thrombin time and activated partial thromboplastin time were measured in all animals. Thrombus developed in 90% of the animals in the control group, 0% in G2 and G3, 62.5% in G4, 87.5% in G5 and G6. Only in the animals treated with heparin the coagulation tests were prolonged. In conclusion, in the used dose only the heparan sulfate from beef pancreas presented an antithrombotic effect similar to heparin in this experimental model.

Influence of nitroreductase and O-acetyltransferase on the mutagenicity of substituted nitrobenzothiophenamines in Salmonella typhimurium.

The mutagenic activity of 17 substituted (aryl)(2-nitrobenzo[b]thiophen-3yl)amines has been evaluated in the Ames test with different isogenic strains of Salmonella typhimurium, that varied in their expression of nitroreductase and O-acetyltransferase. Active derivatives induced frameshift mutations in TA98 strain, and differences in the chemical structure resulted in up to 15-fold changes in mutagenic activity. The non-mutagenic compounds are the unsubstituted parent compound and derivatives with para-chloro, para-fluoro, para-diethylamino, meta-bromo and para-dimethylamino groups. They do not show any activity even in strains with higher level of nitroreductase or O-acetyltransferase. The addition of S9 fraction decreases the mutagenic potential or gives comparable results to those obtained without metabolic activation. For electron-donating substituents, the meta-isomers display the greatest mutagenic potency, whereas the transfer of the group to the para-position leads to less active or unactive molecules. All active nitrobenzothiophenes are substrates for bacterial nitroreductase and O-acetyltransferase, as shown by the reduced mutagenicity in the deficient strains and increased mutagenicity in the corresponding overproducing bacteria. Previous reports have pointed out interest in nitrothiophene analogues with para-chloro and para-fluoro substituents as promising anti-inflammatory drugs. The present study further enhances the putative interest in these derivatives, based on absence of mutagenicity.

Bromodeoxyuridine labelling as an alternative method to identify 6-thioguanine-resistant mutant lymphocytes in humans.

6-Thioguanine-resistant (TGR) mutant lymphocytes in human blood are usually enumerated by the cloning assay which allows the molecular characterisation of the HPRT mutations to be detected. A "short-term" alternative approach is provided by the anti-bromodeoxyuridine (anti-BrdU) technique in which TGR lymphocytes are identified immunocytochemically by their ability to synthesise DNA in the presence of 6-thioguanine (TG). We have evaluated the influence of various experimental factors that could affect the frequency of TGR lymphocytes. A standard protocol is proposed, based on 24-h cold storage of isolated lymphocytes at 4 degrees C and 40-h culture with and without TG, the last 16 h with BrdU. The harvested cells are treated with hypotonic (0.075 M) KCl, fixed with methanol:acetic acid (3:1) and put on microscopic slides. For the TG cultures, all cells are prepared on the slides, while slides from the control cultures are made by a 1/50 dilution. DNA is denatured by formamide, and the BrdU label is identified by anti-BrdU antibody detected by immunoperoxidase staining using a peroxidase-conjugated secondary antibody with diaminobenzidine as substrate. In 10 donors, the frequency of TGR lymphocytes (variant frequency, Vf) detected by this protocol ranged from 69.65 x 10(-6) to 83.45 x 10(-6), and split measurements showed a relatively small intra-assay variation in Vf values of each donor. BrdU in DNA was also detected by immunofluorescence using a fluorescein-conjugated anti-BrdU monoclonal antibody. This method, facilitating easy identification of positive cells and rapid microscopic scoring, may serve as a basis for an automated analysis of TGR lymphocytes. Vf values detected by the anti-BrdU assay are higher than mutant frequencies obtained by the cloning assay, which has been assigned to the presence of non-mutant phenocopies considered to represent spontaneously cycling lymphocytes. Although the anti-BrdU assay is rapid and easy and has been shown to respond to genotoxic exposures, its true value could be evaluated only when it can be ascertained that phenocopies do not significantly contribute to the Vf values obtained.

Cytogenetic effects of Metalaxyl on human and animal chromosomes.

The purpose of this study was to assess the cytogenetic effects in vitro and in vivo of a commonly used fungicide, Metalaxyl. Chromosome damage in vitro, quantified by cultured human peripheral blood lymphocytes, demonstrated dose-related effects not associated with mitotic inhibition or cell death. Significant induction of chromosomal aberrations was observed with between 300 and 1000 micrograms/ml Metalaxyl in the absence of microsomal activation. Incubation in the presence of S9 mix produced less cytogenetic damage. Single i.p. injections of 75-300 mg/kg Metalaxyl had no effect on the frequency of micronuclei, detected in murine polychromatic erythrocytes. Micronuclei results were not compromised by direct evidence of cytotoxicity in the bone marrow of treated animals. The results in the present study indicated that genotoxicity of Metalaxyl was detected only in vitro and not in vivo. Available data reported that Metalaxyl was non-carcinogenic and gave negative results in a battery of genotoxicity tests. So, clastogenicity of Metalaxyl may not be evidence for DNA reactivity, but it may indicate alterations in cell homeostasis which are well implicated in the process of carcinogenesis.

Mutagenic and clastogenic activity of gastric juice in human gastric diseases.

To investigate whether subjects with low-acid states are exposed to increased genetic risk with respect to controls, we evaluated mutagenicity and presence of clastogenic factors (CF) in the gastric juice of chronic atrophic gastritis and omeprazole-treated patients. Mutagenic gastric juice was found in 8/15 (53%) chronic atrophic gastritis patients, 8/11 (73%) omeprazole-treated patients, and 2/13 (15%) healthy control subjects. The mean mutagenicity ratio of omeprazole-treated patients (1.52+/-0.48/0.1 ml gastric juice) was significantly higher than those of either controls (1.07+/-0.15; P<0.01) or chronic atrophic gastritis patients (1.16+/-0.21; P<0.05). Only chronic atrophic gastritis patients showed an increased clastogenic index with respect to healthy controls (2.67+/-2.13 versus 0.38+/-0.51; P<0.001). These findings expand our knowledge of gastric disease risk factors, and indicate that there may well be a risk of mucosal DNA damage arising from the presence of mutagenic and CF in the gastric juice.

Genetic and non-genetic biomarkers related to carcinogenesis in evaluating toxicological risk from Fenarimol.

A multibiomarker approach based on the study of toxicity mechanisms at both genetic and metabolic levels has been applied to Fenarimol. With regard to genotoxicity, particular attention was given to assays for chromosomal aberration and micronuclei; clastogenic potential was assessed in human peripheral blood lymphocytes in vitro, while the induction of micronuclei was studied in male CD1 mouse bone marrow polychromatic erythrocytes (PCE). Fenarimol did not induce any significant dose-related increase in micronucleated PCEs, up to 4-fold above the control level at a single dose of 75 mg/kg b.w., was observed 24 h after treatment. Using selective biochemical markers of effect Fenarimol was found to induce CYP 2B1 isoforms in liver, kidney and lung microsomes of Swiss Albino CD1 male and female mice, as shown by the significant increase in specific 2B1-probe pentoxyresorufin O-dealkylase activity. On the contrary, CYP 3A, probed by N-demethylation of aminopyrine, were only induced in the liver. Results were corroborated by means of Western immunoblotting using rabbit polyclonal antibodies anti-CYP 2B1 and 3A. Northern blotting analysis with CYP 2B1 and 3A cDNA biotinylated probes showed that the expression of such isoforms is regulated at mRNA level. Taken as a whole, these data indicate the possible (mutagenic) cotoxic/cocarcinogenic and promoting potential of this fungicide.

Synthesis, metabolism and structure-mutagenicity relationships of novel 4-nitro-(imidazoles and pyrazoles) in Salmonella typhimurium.

A new series of 4-nitro-(imidazoles and pyrazoles) were synthesized as novel antimycotics and tested for their activation to mutagenic forms using Salmonella typhimurium TA98 and TA100, in the presence and in the absence of metabolic activation. TA100NR, TA100/1,8-DNP6, YG1026 and YG1029 strains were employed to identify a specific metabolic reaction which governs the mutagenic potency. Derivatives in the pyrazole group were generally found to be non mutagenic and active imidazoles were weak-direct-acting mutagens. For most of the compounds the mutagenic responses in TA98 were absent or 12- to 22-fold lower compared to TA100. The presence of a methyl or a benzylic group on the imidazole ring and substituents on the N1 and N3 positions were determinant for mutagenicity. Metabolism by bacterial enzyme systems was important to the expression of genotoxicity. Active compounds showed no mutagenicity toward the strain defective in classical nitroreductase and increased mutagenicity, from 2- to 7-fold depending on the test compound, toward the corresponding overproducing bacteria. On the other hand, compounds displayed reduced mutagenicity to the O-acetyltransferase strain without having increased activity in the corresponding overproducing bacteria, YG1029.

Genetic safety evaluation of pesticides in different short-term tests.

Cyanazine, cyhexatin, dicamba and DNOC are pesticides commonly and broadly used in agriculture pest control. However, there is little information on their toxicity and mutagenicity in human cells and in whole animals. Therefore, UDS assay and SCE assay in human peripheral lymphocytes, and chromosome aberration analysis in bone marrow of rats have been used to assess the DNA-damaging activity of the above pesticides. Cyanazine proved non-genotoxic in all the test systems. Cyhexatin showed only weakly positive results for SCE induction in human lymphocytes, providing no concern for genotoxicological hazard. While dicamba did not show clastogenic effects in rodents, DNOC gave significant dose-related increases of structural chromosome aberrations in rat bone marrow cells. Female animals showed increased sensitivity to the toxic effects by DNOC at the highest dose. The results provide further information on the intrinsic genotoxic activity of the tested pesticides, which may contribute to the toxicological assessment of the risk associated with human exposure.

Influence of different routes of flush perfusion on the distribution of lung preservation solutions in parenchyma and airways.

OBJECTIVE: The present study was performed to investigate the influence of different routes of perfusion on the distribution of the preservation solutions in the lung parenchyma and upper airways. METHODS: Pigs were divided into four groups: control (n = 6), pulmonary artery (PA) (n = 6), simultaneous PA + bronchial artery (BA) (n = 8), and retrograde delivery (n = 6). After preparation and cannulation, cardioplegia solution and Euro-Collins solution (ECS) for lung preservation were given simultaneously. After removal of the heart, the double lung bloc was harvested. Following parameters were assessed: total and regional perfusion (dye-labeled microspheres), tissue water content, PA, aorta, left atrial and left ventricular pressures, cardiac output and lung temperature. RESULTS: Our data show that flow of the ECS in lung parenchyma did not reach control values (9.4+/-1.0 ml/min per g lung wet weight) regardless of the route of delivery (PA 6.3+/-1.5, PA + BA 4.8+/-0.9, retrograde 2.7+/-0.9 ml/min per g lung wet weight). However, flow in the proximal and distal trachea were significantly increased by PA + BA delivery (0.970+/-0.4, respectively, 0.380+/-0.2 ml/min per g) in comparison with PA (0.023+/-0.007, respectively, 0.024+/-0.070 ml/min per g), retrograde (0.009+/-0.003, respectively, 0.021+/-0.006 ml/min per g) and control experiments (0.125+/-0.0018, respectively, 0.105+/-0.012 ml/g per min). Similarly the highest flow rates in the right main bronchus were achieved by PA + BA delivery (1.04+/-0.4 ml/min per g) in comparison with 0.11+/-0.03 in control, 0.033+/-0.008 in PA, and 0.019+/-0.005 ml/min per g in retrograde group. Flows in the left main bronchus were 0.09+/-0.02 ml/min per g in control, 0.045+/-0.012 ml/min per g in PA, and 0.027+/-0.006 ml/min per g in retrograde group. The flow rates were significantly (P = 0.001) increased by PA + BA delivery of the storage solution (0.97+/-0.3 ml/min per g). CONCLUSIONS: Our data show that the distribution of ECS for lung preservation is significantly improved in airway tissues (trachea and bronchi) if a simultaneous PA + BA delivery is used.

The involvement of reactive oxygen species in the direct-acting mutagenicity of 5-nitro-3-thiophenecarboxanilides in Salmonella typhimurium.

The primary basis of 5-nitro-3-thiophenecarboxanilides (NTCAs) direct-acting mutagenicity in Salmonella typhimurium appears to be the reduction of the nitro function to the corresponding hydroxylamine via diamagnetic and free radicals intermediates. In Ames test conditions, mutagenicity of NTCAs may be partly attributed to the action of reactive oxygen species and other radicals generated during the bioreductive process. The nitro anion radical seems to be particularly susceptible to react with oxygen and generate superoxide, as shown by the inhibitory effects exerted by superoxide dismutase on genotoxicity by most NTCAs in the study. On the other hand, hydroxyl radical-trapping agents such as mannitol, the enzyme catalase and other scavengers as 3-tert-butyl-4-hydroxyanisole (BHA), and vitamins C, A, and E showed weak inhibitory potency, and rather increased the mutagenic activity of some NTCAs. Our results contribute to the mechanistic understanding of genotoxic activity of NTCAs.