Olaquindox-induced airborne photoallergic contact dermatitis followed by transient or persistent light reactions in 15 pig breeders

Subchronic toxicity and hepatocyte apoptosis of dietary olaquindox in common carp (Cyprinus carpio)

Olaquindox as one of the effective antimicrobial agents and growth-promoting feed additives, had been widely used in animal and fish production. However, few studies have been done to unveil its possible toxic effect and tissue injury on aquatic animal. In this study, the toxic effect and underlying mechanisms of olaquindox toxicity were investigated in common carp when feed with different doses of olaquindox for 90 days. The morbidity and mortality, pathological changes, hematology parameters, residue concentration in the tissues of common carp were assessed, hepatocyte apoptosis was detected through ultrastructural observation and flow cytometry methods. The results showed that the morbidity and mortality increased with the increasing dosages of dietary olaquindox, subchronic exposure to olaquindox caused remarkably pathological changes, including congestion and bleeding, intramuscular edema, vacuolar degeneration, degeneration and deformation in renal tubules architecture, respiratory epithelium fusion and intestinal epithelial microvilli disintegration. Besides, dietary olaquindox led to significant changes in blood biochemical parameters including red blood cell, hemoglobin, alanine aminotransferase and aspartate aminotransferase, an elevated residue concentration of olaquindox was detected in liver and kidney after exposure, hepatocyte apoptosis and necrosis were observed. Moreover, insulin-like growth factor I (IGF-I) mRNA level in liver was higher than normal level with the dose below 25 mg/kg olaquindox and was lower than normal level with the dose above 50 mg/kg. Our results demonstrated that dietary olaquindox may pose subchronic toxicity and residue in fish organs and provided scientific data for the safe application of olaquindox in fish.

Olaquindox induces apoptosis through the mitochondrial pathway in HepG2 cells

Olaquindox is used in China as feed additive for growth promotion in pigs. Recently, we have demonstrated that olaquindox induced genome DNA damage and oxidative stress in HepG2 cells. The aim of this study was to explore the molecular mechanism of cell cycle arrest and apoptosis induced by olaquindox in HepG2 cells. In the present study olaquindox induced cell cycle arrest to the S phase and dose-dependent apoptotic cell death in HepG2 cells, indicated by accumulation of sub-G1 cell population, nuclear condenstion, DNA fragmentation, caspases activation and PARP cleavage. Meanwhile, the data showed that olaquindox triggered ROS-mediated apoptosis in HepG2 cells correlated with both the mitochondrial DNA damage and nuclear DNA damage, collapse of Δψ(m), opening of mPTP, down-regulation of Bcl-2 and up-regulation of Bax. Furthermore, we also found that olaquindox increased the expression of p53 protein and induced the release of cytochrome C from mitochondria to cytosol. In conclusion, olaquindox induced apoptosis of HepG2 cells through a caspase-9 and -3 dependent mitochondrial pathway, involving p53, Bcl-2 family protein expression, Δψ(m) disruption and mPTP opening.

A novel in vitro method for the detection and characterization of photosensitizers

Photoactivation and binding of photoactive chemicals to proteins is a known prerequisite for the formation of immunogenic photoantigens and the induction of photoallergy. The intensive use of products and the availability of new chemicals, along with an increasing exposure to sun light contribute to the risk of photosensitizing adverse reactions. Dendritic cells (DC) play a pivotal role in the induction of allergic contact dermatitis. Human peripheral blood monocyte derived dendritic cells (PBMDC) were thus perceived as an obvious choice for the development of a novel in vitro photosensitization assay using the modulation of cell surface protein expression in response to photosensitizing agents. In this new protocol, known chemicals with photosensitizing, allergenic or non-allergenic potential were pre-incubated with PBMDCs prior to UVA irradiation (1 J/cm(2)). Following a 48 h incubation, the expression of the cell surface molecules CD86, HLA-DR and CD83 was measured by flow cytometry. All tested photosensitizers induced a significant and dose-dependent increase of CD86 expression after irradiation compared to non-irradiated controls. Moreover, the phototoxicity of the chemicals could also be determined. In contrast, (i) CD86 expression was not affected by the chosen irradiation conditions, (ii) increased CD86 expression induced by allergens was independent of irradiation and (iii) no PBMDC activation was observed with the non-allergenic control. The assay proposed here for the evaluation of the photoallergenic potential of chemicals includes the assessment of their allergenic, phototoxic and toxic potential in a single and robust test system and is filling a gap in the in vitro photoallergenicity test battery.

Experimental evaluation of cyadox phototoxicity to Balb/c mouse skin

BACKGROUND

Cyadox is a veterinary drug mainly used as an effective antimicrobial promoter in animal husbandry. It was reported that the other quinoxaline-1,4-dioxide compounds had phototoxicity, but only few data are reported on phototoxicity of cyadox. This study was performed to evaluate the phototoxicity of cyadox on skin.

METHODS

Eighty mice were equally divided into eight groups. Five groups with ultraviolet A (UVA) irradiation for 2 h (21 J/cm2) were administered at doses of 0, 10, 50, 200 mg/kg cyadox and 50 mg/kg olaquindox, respectively, and others as controls without irradiation administered at doses of 0, 200 mg/kg cyadox and 50 mg/kg olaquindox, respectively. Drugs were administered by gavage once daily with a suspension in 0.8% carboxymethyl-cellulose for consecutive 4 days. After administration, a recovery period of 7 days was arranged. Histopathological examination of auricular skin was performed on days 5 and 12. Measurement of auricular thickness, gross pathology and erythema score were conducted once daily.

RESULTS

Cyadox groups (200, 50 and 10 mg/kg) with irradiation had erythema and oedema of auricular skin with dose-response relationship, which gradually convalesced after dosing and irradiation ceased. Severe erythema, oedema and necrosis of auricles were observed on olaquindox group with irradiation.

CONCLUSION

The phototoxicity of cyadox was mild and reversible, which demonstrated a good safety profile of cyadox in terms of phototoxicity.

Subchronic oral toxicity study with cyadox in Wistar rats

To investigate the potential subchronic toxicity of cyadox, groups of 15 male and 15 female Wistar rats were fed with diets containing cyadox (0, 50, 150 or 2500 mg/kg) or olaquindox (150 mg/kg), approximately equivalent to cyadox 5, 15, 250 or olaquindox 15 mg/kg b.w./day, for 13 weeks. Five rats/sex/group were sacrificed on days 30, 60 and 90. No test-material-related changes were seen in mortality, clinical signs, hematology, clinical chemistry, organ weight data and macroscopic examinations. Except that body weights of both sexes of the 2500 mg/kg cyadox group were significantly lower than controls beginning after the second week of treatment. Body weights of females of 150 mg/kg olaquindox group were significantly lower than those of the control group at weeks 3 and 4. Other groups were unaffected by treatments. Histopathological observations revealed that 2500 mg/kg cyadox or 150 mg/kg olaquindox induced swelling and fatty degeneration of the hepatocytes and proximal renal tubular epithelial cells. It was for the first time that changes were found in the liver and kidneys of rats fed 2500 mg/kg cyadox. The no-observed-adverse-effect level (NOAEL) of cyadox for rats was estimated to be 150 mg/kg dietary dose level.

Veterinary pharmacovigilance. Part 4. Adverse reactions in humans to veterinary medicinal products

Although seemingly rare, adverse reactions to veterinary products do occur. These may arise from inadvertent exposure during use or as a result of occupational accidents. They are often mild in nature and include adverse effects such as minor skin reactions. However, more serious reactions may occur, and they are not restricted to the effects of the veterinary medicines themselves. For example, high-pressure injection injuries may occur as a result of accidents occurring during animal vaccination operations. This paper reviews some of these events, mentions where appropriate the regulatory actions taken, and describes some of the measures used to minimise such effects in the future, and serves to bring the issues discussed here to the attention of pharmacologists, pharmacoepidemiologists and others who train those who use veterinary medicinal products.

Photocontact dermatitis

Photocontact dermatitis is not a common condition, but neither is it rare. Both photo-irritant contact dermatitis (PICD) and photoallergic contact dermatitis (PACD) are seen by most dermatologists in general practice. PICD is diagnosed on clinical grounds and is usually caused by furocoumarins in plants like limes and celery. PACD is caused primarily by sunscreens but can also be the result of fragrances and antibacterial agents. PACD can only be diagnosed by photo-patch testing that most dermatologists, even those who patch test and give phototherapy in their office, do not perform. The procedure as outlined in this manuscript is relatively simple and can easily be accomplished in the dermatologist's office.

Photoallergic contact dermatitis

PURPOSE

To determine whether photoallergic contact dermatitis is as uncommon as it is usually considered to be and to review the associated clinical features.

METHODS

We reviewed the literature on photoallergic reactions induced by the topical contact of the skin with a chemical in the presence of, or followed by, exposure to UV or visible light. Some of the more recently observed photo-allergens and those presenting special clinical features are discussed.

RESULTS

The literature cites several topical substances that give rise to photoallergic contact dermatitis, some of them only exceptionally but others quite frequently. The clinical features are not always those of a eczematous eruption, and several parts of the body may be affected.

CONCLUSIONS

Many topical photoallergic culprits have been reported in the literature, the most important of which are sunscreen agents and, recently, non-steroidal anti-inflammatory agents (NSAIDs). Not at all exceptional is the occurrence of photoaggravation and recurrent transient or even persistent light reactions on previously exposed as well as non-exposed areas (often sparing the original application site), particularly with the NSAID ketoprofen. Moreover, cross-reactions with chemically-related as well as non-chemically related molecules are common. The potentially misleading clinical features observed in some cases, the diversity of the casual substances identified, and the low frequency with which photopatch testing is carried out in general indicate that the occurrence of photoallergic contact dermatitis might well be underestimated.

Fragrance allergy and hand eczema - a review

Because hand eczema and fragrance allergy are common both among patients and in the general population, simultaneous occurrence by chance must be expected. Fragrances are ubiquitous and a part of many domestic and occupational products intended for hand exposure. The present review is based on a systematic literature research using both a manual and a Medline based search. The search identified 39 studies, including epidemiological patch test studies, general population patch test studies, case studies, and studies of occupational groups. The published data indicate a possible association between fragrance allergy and hand eczema. In future studies, a more detailed exposure assessment is needed, combined with patch test studies among patients with hand eczema tested with relevant fragrance allergens, as well as experimental control exposure studies to specific fragrance allergens on the hands. As exposures to fragrances on the hands are often simultaneous exposures to irritants, this combined exposure approach needs to be considered.

An update on airborne contact dermatitis

This review is an update of 2 previously published articles on airborne contact dermatoses. Because reports in the literature often omit the term 'airborne', 18 volumes of Contact Dermatitis (April 1991-June 2000), 8 volumes of the American Journal of Contact Dermatitis (1992 1999) and 4 volumes of La Lettre du Gerda (1996-1999) were screened, and the cases cited were classified as to history, lesion locations, sensitization sources, and other factors. Reports on airborne dermatitis are increasingly being published, sometimes in relation to specific occupational areas.

Allergic contact dermatitis to ethoxyquin in a farmer handling chicken feeds

Farm workers handling animal feeds are exposed to a variety of chemicals, some of which may cause allergic contact dermatitis. A case of allergy to ethoxyquin (a preservative added to chicken feed to inhibit vitamin degradation) in a chicken farmer is presented. Although the offending allergen was identified in this patient, it proved difficult to find ethoxyquin-free chicken feed products and the patient's dermatitis persisted. When facing the clinical problem of dermatitis in animal workers, the possibility of allergic contact dermatitis to components in animal feeds must be considered.