Giuseppe Crescenzo

AFLATOXINS IN AQUATIC SPECIES: METABOLISM, TOXICITY AND PERSPECTIVES

Among all known mycotoxins, aflatoxins represent the most investigated, widespread and worrisome source of contamination of foods and feed worldwide. In the early 1960s, soon after the finding of aflatoxin B1 (AFB1) in the feedstuffs of aquacultured rainbow trout that had died in an epizootic of hepatomas, great scientific discoveries were made in several areas by a number of researchers under the direction of scientists like J. Halver, R. 0. Sinnhuber, G. S. Bailey, J. D. Hendricks and colleagues. Since that time, several studies have focused on the identification of new isoenzymes involved in AFB1 metabolism and on the discovery of new modulators in AFB1-induced cancer initiation and progression. However, metabolic and toxicological studies on aflatoxins in marine aquacultured species are fragmented and restricted to a limited number of fish species. Aflatoxins exert a substantial impact on the fish farming production, causing disease with high mortality and a gradual decline of reared fish stock quality, thus representing a significant problem in aquaculture systems. Based on these considerations, the goals of this review article are: (1) to gather the currently available scientific information, summarising existing data on aflatoxin contamination on feeds and fishmeals, and toxicological effects induced in reared aquatic species; (2) to make a comparative analysis of AFB1 metabolism in the most representative species studied; (3) to gain new insights on the risk of DNA damage caused by aflatoxins on fish genomes and their role in cancer development.

Long-term viremia and fecal shedding in pups after modified-live canine parvovirus vaccination

Abstract Canine parvovirus (CPV) modified live virus vaccines are able to infect vaccinated dogs replicating in the bloodstream and enteric mucosa. However, the exact duration and extent of CPV vaccine-induced viremia and fecal shedding are not known. With the aim to fill this gap, 26 dogs were administered two commercial vaccines containing a CPV-2 or CPV-2b strain and monitored for 28 days after vaccination. By using real-time PCR, vaccine-induced viremia and shedding were found to be long lasting for both vaccinal strains. Vaccinal CPV-2b shedding was detected for a shorter period than CPV-2 (12 against 19 mean days) but with greater viral loads, whereas viremia occurred for a longer period (22 against 19 mean days) and with higher titers for CPV-2b. Seroconversion appeared as early as 7 and 14 days post-vaccination for CPV-2b and CPV-2 vaccines, respectively. With no vaccine there was any diagnostic interference using in-clinic or hemagglutination test, since positive results were obtained only by fecal real-time PCR testing. The present study adds new insights into the CPV vaccine persistence in the organism and possible interference with diagnostic tests.

Pharmacokinetics of imidocarb dipropionate in horses after intramuscular administration

The objective of this study was to determine the pharmacokinetic behaviour of imidocarb in horses following a single i.m. injection at the dose commonly administered to treat Babesia caballi infections or to prevent babesiosis. Eight horses were injected i.m. with a single dose of 2.4 mg imidocarb dipropionate/kg bwt and blood, faecal, urine and milk samples were collected. For imidocarb determination, a high-performance liquid chromatographic method (HPLC) was used after weak cation-exchange solid phase, or liquid-liquid, extraction procedures. Twelve hours after treatment, no detectable plasma concentrations were recorded in any of the treated animals. The distribution and elimination patterns of the drug suggested that it is quickly sequestrated in some storage tissues and remains in the body for a long time. Its prolonged presence in the body may confer a reservoir effect to imidocarb in some tissues, therefore making it undetectable in the plasma of animals but sufficient to produce its described therapeutic and prophylactic activities.

Pharmacokinetic Behavior of Enrofloxacin in Estuarine Crocodile (Crocodylus porosus) after Single Intravenous, Intramuscular, and Oral Doses

Abstract The disposition kinetics of enrofloxacin at a single dose of 5 mg/kg body weight were determined in clinically healthy captive-reared estuarine crocodiles (Crocodylus porosus) after intravenous (i.v.), intramuscular (i.m.), and oral (p.o.) administration. Enrofloxacin plasma concentrations were determined by diode array detection–high-performance liquid chromatography (limit of detection/limit of quantitation: 0.05 µg/ml). Data were subjected to noncompartmental analysis. The integrated pharmacokinetic-pharmacodynamic (PK-PD) variables showed that optimal area under the curve from the time of dosing to 24 hr:minimal inhibitory concentration (MIC) (>125) and peak plasma concentrations:MIC (>8) ratios, as reported for concentration-dependent bactericidal antimicrobials like fluoroquinolones, were achievable with both a single i.v. or i.m. dose for susceptible microorganisms with MIC values of ≤0.5 µg/ml, while the relatively slow onset of peak time allowed an effective plasma drug level only on day 3. The persistence of useful plasma concentrations indicated the possibility of redosing every 3 day for parenteral routes of administration, while further studies are needed for the oral route. Nevertheless, the absence of adverse reactions in the animals following i.v., i.m., or p.o. administration of enrofloxacin after a single dose of 5 mg/kg indicates the possibility of its safe and effective clinical use in captive estuarine crocodiles.

Pharmacokinetic Behavior of Meloxicam in Loggerhead Sea Turtles (Caretta caretta) after Intramuscular and Intravenous Administration

Abstract Data on reptile analgesia are scarce for nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids and almost completely lacking in sea turtles, even though emergencies requiring correct pain management are very frequent in their rehabilitative medicine; therefore, dosage regimens extrapolated from other species involve the risk of clinical failure and damage to the animals. We describe the pharmacokinetic behavior of meloxicam in the loggerhead sea turtle (Caretta caretta). We chose meloxicam because of its selective anti-cyclooxygenase-2 activity and lesser adverse side effects. No data are available on the capacity of turtles to tolerate NSAIDs, so we chose a dose of 0.1 mg/kg of meloxicam. Plasma concentrations of meloxicam were unexpectedly low both for intravenous (IV; maximum concentration [Cmax] = 0.04±0.02 µg/mL) and intramuscular (IM; Cmax = 0.07±0.09 µg/mL) administration. A double-peak phenomenon occurred after both IV (time for second peak concentration Tmax2 = 10.33±10.89 h) and IM (Tmax2 = 1.17±0.75 h). The second peak after IM injection was premature, so some difficulty and delay in absorption appears to be an appropriate explanation. Furthermore, the area under the curve, and therefore systemic bioavailability (F = 31.82±28.24%), after both IV (0.30±0.29) and IM (0.10±0.03) injection appeared particularly limited. Terminal elimination slope and mean residence time indicated fast elimination after IM dosing; as a consequence, plasma concentrations dropped below analytic limits in 8 h. Considering that IM is the favored route of administration of drugs in rescue centers, it is unlikely that meloxicam at 0.1 mg/kg is an appropriate choice, particularly in long-term pain management protocols.

Assessing the Efficacy of Cidofovir against Herpesvirus-Induced Genital Lesions in Goats Using Different Therapeutic Regimens

ABSTRACT Caprine herpesvirus 1 (CpHV-1) infection in goats induces genital vesicular-ulcerative lesions that strictly resemble those produced by human herpesvirus 2 in humans. In previous studies, the potent inhibition of CpHV-1 by cidofovir was demonstrated. Cidofovir antiherpetic activity was evaluated in goats infected experimentally by the vaginal route with CpHV-1 and then treated locally at different times after infection. The administration of 1% cidofovir cream onto vaginal mucosa was able to prevent the onset of genital lesions and to decrease significantly the titers of the virus shed by the infected animals, notably in the groups treated shortly after infection (24 and 48 h). The efficacy of cidofovir against caprine herpesvirus infection was higher when the treatment was started shortly after infection than when lesions were already present and advanced. Herpesvirus genital infection of goats is a useful animal model to study the activity of antiviral drugs against human herpesvirus infections.

Pharmacokinetics of marbofloxacin after a single oral dose to loggerhead sea turtles (Caretta caretta).

The single-dose disposition kinetics of marbofloxacin (MBX) were determined in clinically healthy loggerhead sea turtles (n=5) after oral (PO) administration of 2 mg kg(-1) bodyweight. Marbofloxacin plasma concentrations were determined by DAD-HPLC (LOD/LOQ 0.015/0.05 microg ml(-1)). Data were subjected to non-compartmental analysis. Following PO administration, marbofloxacin achieved maximum plasma concentrations of 11.66+/-2.53 mg L(-1) at 15.00+/-3.00 h. The absence of general adverse reactions in the turtles of the study, and the favourable pharmacokinetic properties (long half-life and high maximum plasma concentration) of MBX administered PO at the single-dose of 2 mg kg(-1) suggest the possibility of its safe and effective clinical use in loggerhead sea turtles.

Pharmacokinetics of Marbofloxacin in Loggerhead Sea Turtles (Caretta caretta) after Single Intravenous and Intramuscular Doses

Abstract The disposition kinetics of marbofloxacin at a single dose of 2 mg/kg bodyweight were determined in a crossover trial with five clinically healthy loggerhead sea turtles (Caretta caretta) after i.v. and i.m. administration. Marbofloxacin plasma concentrations were determined by high-performance liquid chromatography (LOD/LOQ 0.05 µg/ml). Data were subjected to noncompartmental analysis. The integrated pharmacokinetic/pharmacodynamic variables showed that optimal area under the curve (AUC0–24 h): minimal inhibitory concentration (MIC) (>125) and Cmax: MIC (>8) ratios, as reported for concentration-dependent bactericidal antimicrobials (e.g., fluoroquinolones), were achievable with both a once daily i.v. or i.m. dose for microorganisms with MIC ≤ 0.5 µg/ml, while a Cmax: MIC > 8 for MIC ≥ 1 µg/ml was achievable only after the i.v. administration. The absence of adverse reactions in the animals after i.v. or i.m. administration of marbofloxacin and the favorable pharmacokinetic/pharmacodynamic properties after a single dose of 2 mg/kg suggest the possibility of its safe and effective clinical use in loggerhead sea turtles.

Implications for chronic toxicity of benzo[a]pyrene in sea bream cultured hepatocytes: Cytotoxicity, inflammation, and cancerogenesis.

Benzo[a]pyrene (B[a]P) is the most studied dangerous polycyclic aromatic hydrocarbon for its hepatotoxic, carcinogenic, mutagenic, teratogenic, and immunosuppressant effects, which can affect both wild and farmed marine fish through the trophic chain. This study investigated, for the first time, the chronic effects induced in vitro by B[a]P prolonged exposure on gilthead sea bream (Sparus aurata L.) hepatocytes, evaluating the cellular and nuclear latent damage. The purpose was to characterize the kind of B[a]P cyto‐ and genotoxic damage by morphological and immunocytochemical parameters applied in combination with the use of multiple assay endpoints. In light of our results, the short‐term effects at higher B[a]P doses were linked to higher cytotoxicities and necrotic lysis, whereas a sustained inflammatory response at medium–low doses was perceived as a mitochondria‐mediated apoptosis, both by surface and nuclear morphological changes. The strong immunoreactivity for the cleaved caspase‐3 showed that the labeled cells committed suicide by apoptosis. B[a]P involvement on carcinogenesis comes from prolonged exposure at lower doses, establishing the connection between the escape from apoptosis and the selection of a tumoral phenotype. Cells colabeled with proliferating cell nuclear antigen/caspase‐3 within the proliferative foci, were proliferating transformed oval stem cells, which escaped the suicide by apoptosis allowing cancer development. Finally, it was established that sea bream cultured hepatocytes are highly sensitive to chronic B[a]P exposure, as serious genotoxic effects were found even at the lowest doses.

Cidofovir does not prevent caprine herpesvirus type-1 neural latency in goats.

BACKGROUND Cidofovir (CDV) is an acyclic nucleoside phosphonate that exhibits a potent antiviral activity against several DNA viruses. In previous studies, CDV has been shown to significantly reduce the clinical severity and the viral shedding in primary caprine herpesvirus type-1 (CpHV-1) infection in goats. CpHV-1 is an alpha-herpesvirus showing many biological similarities with human herpesvirus type-2 (HHV-2); therefore, studies conducted on the CpHV-1 goat model could provide useful information on the pathogenesis, therapy and prevention of HHV-2 infection in humans. METHODS CDV was administered to goats infected by vaginal route with CpHV-1. Real-time PCR was carried out on sacral ganglia from CpHV-1-infected goats to detect and quantify latent CpHV-1 DNA. RESULTS Viral DNA was variably found in all five pairs of sacral ganglia, with a more frequent involvement of the third and fourth pair. In CDV-treated goats, the amount of CpHV-1 DNA did not appear to be related either to the severity of the clinical signs or the titre of the virus shed during primary CpHV-1 infection. CONCLUSIONS CDV failed to prevent CpHV-1 latency. Thus, vaginal CDV administration during primary herpesvirus infection, although providing immediate clinical benefits to the host might not influence the establishment of latency and, consequently, the rate of recurrent infections.