Host preference and host colonization of the Asian long-horned beetle, Anoplophora glabripennis (Coleoptera Cerambycidae), in Southern Europe.

The Asian long-horned beetle (ALB), Anoplophora glabripennis (Motschulsky), is a highly polyphagous invasive pest with a broad range of host species, but showing relevant differences between infestation areas. Host preference and host colonization (female fecundity, egg and larval survival) were assessed in a population in Northern Italy by choice and no-choice experiments conducted in both field and laboratory conditions. During 5 years of field observations, ALB was found to infest seven genera of trees: Acer, Aesculus, Betula, Populus, Prunus, Salix and Ulmus. However, Acer, Betula, Ulmus and Salix resulted to be the preferred hosts corresponding to 97.5% (1112) of the 1140 infested trees. In both laboratory and field trials carried out on these four host genera, no-choice experiments recorded the highest host colonization of A. glabripennis on Acer trees, with the highest number of laid eggs and the lowest egg and larval mortality. Ulmus and Salix showed a lower number of laid eggs during laboratory choice test, but egg and larval mortality had mean values similar to Acer. On the contrary, despite the high number of Betula trees felled during the eradication plan carried out in the infestation area, this tree species showed the lowest beetle suitability in terms of number of laid eggs and insect survival. An overestimation of the number of infested Betula occurring during the tree survey may explain the discordance between high number of infested Betula and low beetle suitability. Instead, the large number of infested Acer recorded in the field was probably due to the high abundance of these trees occurring in parks and gardens within the infestation area and to the low adult dispersal of A. glabripennis. Overall, results from this study confirm that host species affects both beetle colonization and breeding performance. The study shows ALB host preference and host suitability varying between tree species, suggesting an ALB acceptance even of sub-optimal hosts.

Emx2 is a dose-dependent negative regulator of Sox2 telencephalic enhancers.

The transcription factor Sox2 is essential for neural stem cells (NSC) maintenance in the hippocampus and in vitro. The transcription factor Emx2 is also critical for hippocampal development and NSC self-renewal. Searching for 'modifier' genes affecting the Sox2 deficiency phenotype in mouse, we observed that loss of one Emx2 allele substantially increased the telencephalic ß-geo (LacZ) expression of a transgene driven by the 5' or 3' Sox2 enhancer. Reciprocally, Emx2 overexpression in NSC cultures inhibited the activity of the same transgene. In vivo, loss of one Emx2 allele increased Sox2 levels in the medial telencephalic wall, including the hippocampal primordium. In hypomorphic Sox2 mutants, retaining a single 'weak' Sox2 allele, Emx2 deficiency substantially rescued hippocampal radial glia stem cells and neurogenesis, indicating that Emx2 functionally interacts with Sox2 at the stem cell level. Electrophoresis mobility shift assays and transfection indicated that Emx2 represses the activities of both Sox2 enhancers. Emx2 bound to overlapping Emx2/POU-binding sites, preventing binding of the POU transcriptional activator Brn2. Additionally, Emx2 directly interacted with Brn2 without binding to DNA. These data imply that Emx2 may perform part of its functions by negatively modulating Sox2 in specific brain areas, thus controlling important aspects of NSC function in development.

Neonicotinoids in the agroecosystem: In-field long-term assessment on honeybee colony strength and microbiome.

Bees can be severely affected by various plant protection products (PPP). Among these, neonicotinoid insecticides are of concern as they have been shown to be responsible for extensive honeybee colonies death when released into the environment. Also, sublethal neonicotinoid doses contaminating single honeybees and their colonies (e.g. through contaminated pollen) are responsible for honeybees physiological alterations with probable implication also on microbiome functionality. Honeybees show symbiotic interactions with specific gut bacteria that can enhance the adult host performances. Among the known mechanisms, the modulation of the immune system, the degradation of recalcitrant secondary plant metabolites, pollen digestion, and hormonal signaling, are the most important functional benefits for the host honeybee. To date, few research efforts have aimed at revealing the impact of PPP on the gut microbial community of managed and wild honeybees. The majority of the existing literature relays on cage or semifield tests of short duration for research investigating neonicotinoids-gut microbiome interactions. This research wanted to unravel the impact of two neonicotinoids (i.e. imidacloprid and thiacloprid) in natural field conditions up to 5 weeks of exposure. A long-term impact of neonicotinoids on gut microbial community of honeybees was observed. The alterations affected several microbial genera and species such as Frischella spp., lactobacilli and bifidobacteria, whose shifting is implicated in intestinal dysbiosis. Long-term impact leading to dysbiosis was detected in case of exposure to imidacloprid, whereas thiacloprid exposure stimulated temporary dysbiosis. Moreover, the microbial diversity was significantly reduced in neonicotinoid-treated groups. Overall, the reported results support a compromised functionality of the gut microbial community, that might reflect a lower efficiency in the ecosystemic functionality of honeybees.

Sox2 is not required for melanomagenesis, melanoma growth and melanoma metastasis in vivo.

Melanoma is a dangerous form of skin cancer derived from the malignant transformation of melanocytes. The transcription factor SOX2 is not expressed in melanocytes, however, it has been shown to be differentially expressed between benign nevi and malignant melanomas and to be essential for melanoma stem cell maintenance and expansion in vitro and in xenograft models. By using a mouse model in which BRafV600E mutation cooperates with Pten loss to induce the development of metastatic melanoma, we investigated if Sox2 is required during the process of melanomagenesis, melanoma growth and metastasis and in the acquisition of resistance to BRAF inhibitors (BRAFi) treatments. We found that deletion of Sox2 specifically in Pten null and BRafV600E-expressing melanocytes did not prevent tumor formation and did not modify the temporal kinetics of melanoma occurrence compared to Sox2 wt mice. In addition, tumor growth was similar between Sox2 wt and Sox2 deleted (del) melanomas. By querying publicly available databases, we did not find statistically significant differences in SOX2 expression levels between benign nevi and melanomas, and analysis on two melanoma patient cohorts confirmed that Sox2 levels did not significantly change between primary and metastatic melanomas. Melanoma cell lines derived from both Sox2 genotypes showed a similar sensitivity to vemurafenib treatment and the same ability to develop vemurafenib resistance in long-term cultures. Development of vemurafenib resistance was not dependent on SOX2 expression also in human melanoma cell lines in vitro. Our findings exclude an oncogenic function for Sox2 during melanoma development and do not support a role for this transcription factor in the acquisition of resistance to BRAFi treatments.

Thyroid hormone reduces inflammatory cytokines improving glycaemia control in alloxan-induced diabetic wistar rats.

AIM: This study aimed at evaluating whether thyroid hormone treatment could improve glycaemia and insulin response in alloxan-induced diabetic rats by altering cytokine expression in the skeletal muscle and epididymal white adipose tissue (eWAT) as well as altering inflammatory cell infiltration in eWAT. METHODS: Diabetes mellitus (DM) was induced in male Wistar rats by alloxan injection, and a subset of the diabetic rats was treated with T3 (1.5 µg per 100 g body weight) for a 28-day period (DT3 ). Cytokines were measured in serum (MILIplex assay kit) as well as in soleus and EDL skeletal muscles and eWAT by Western blotting. Thyroid function was evaluated by morphological, molecular and biochemical parameters. Cardiac function was assessed by measuring heart rate, blood pressure, maximal rate of pressure development (dp/dtmax ) and decline (dp/dtmin ) as well as the contractility index (CI). Sixty rats were used in the study. RESULTS: Diabetic rats exhibited decreased thyroid function and increased inflammatory cytokines in serum, soleus muscle and eWAT. T3 treatment decreased glycaemia and improved insulin sensitivity in diabetic animals. These alterations were accompanied by decreased TNF-alpha and IL-6 content in soleus muscle and eWAT, and inflammatory cell infiltration in eWAT. T3 treatment did not affect cardiac function of diabetic rats. CONCLUSIONS: The present data provide evidence that T3 treatment reduces glycaemia and improves insulin sensitivity in diabetic rats, and that at least part of this effect could result from its negative modulation of inflammatory cytokine expression.

Organisation of the tmb catabolic operons of Pseudomonas putida TMB and evolutionary relationship with the xyl operons of the TOL plasmid pWW0.

In Pseudomonas putida (Pp) TMB the genes involved in the catabolism of methyl-substituted aromatic hydrocarbons 1,2,4-trimethylbenzene, m- and p-xylene (tmb operon), are functionally and genetically homologous to the xyl genes of the plasmid pWW0, but are chromosomally encoded. We have analysed by cloning. Southern blotting and sequencing of selected regions the organisation of the tmb cluster. This analysis shows that the structural and regulatory genes of the tmb and xyl systems exhibit a high degree of homology and are similarly organised in operons. However the operons are differently arranged on the Pp TMB chromosome and on the pWW0 plasmid. Comparison of the two systems suggests that the operon arrangement found in pWW0 may have originated from that found in Pp TMB via cointegration mediated by replicative transposition or by intermolecular recombination between two copies of the insertion element IS1246.

Assessment of vitamin A status in chronic obstructive pulmonary disease patients and healthy smokers.

The relation between vitamin A status and the degree of lung airway obstruction was examined in a cross-sectional study of 36 male subjects aged 43-74 y who were assigned to five groups as follows: healthy nonsmokers (n = 7), healthy smokers (n = 7), mild chronic obstructive pulmonary disease (COPD-mild) patients (n = 9), COPD-moderate-severe patients (n = 7), and COPD-moderate-severe patients with exacerbation (+ex; n = 6). Smoking habits, pulmonary function tests, energy-protein status were assessed; serum concentrations of retinyl esters, retinol, retinol binding protein, and transthyretin and relative dose responses were measured. In addition, 12 male smokers aged 45-61 y with mild COPD were randomly assigned to two groups for a longitudinal study: six subjects consumed vitamin A (1000 RE/d; COPD-vitamin A) and six subjects received placebo for 30 d. Lowered serum retinol concentrations were found in the COPD-moderate-severe and COPD-moderate-severe+ex groups. Measurements of vitamin A status in healthy smokers and in COPD-mild patients were not different from those in healthy nonsmokers. The improvement of pulmonary function test results after vitamin A supplementation [mean increase for 1-s forced expiratory volume (FEV1) = 22.9% in the COPD-vitamin A group] may support the assumption of a local (respiratory) vitamin A deficiency in patients with this disease.

Evaluation of rose bengal staining test and rapid dark-adaptation test for the field assessment of vitamin A status of preschool children in Southern Brazil.

The objective of this study was to evaluate two of several methods presently available for assessing vitamin A status of marginally malnourished preschool children of socioeconomically deprived families in Southern Brazil. The rose bengal staining test and rapid dark-adaptation test were evaluated by comparing their results with conventional methods that require estimation of dietary intake of vitamin A equivalents and determination of plasma levels of retinol before and after an oral supplementation of 200 000 IU vitamin A. Results indicate that neither test evaluated is useful by itself. There was no significant correlation between the results of the rose bengal staining test and the plasma levels of retinol. Also, no significant correlation was observed between the rapid dark-adaptation time and the vitamin A status of the preschool children as determined by plasma-retinol levels before and after vitamin A supplementation.

Vitamin A status of young children in Southern Brazil.

A comprehensive survey was carried out to assess the vitamin A status of preschool children of poor migrant families in the periurban population of Ribeirao Preto, a typical agricultural town in the sugarcane and coffee region of the State of Sao Paulo in Southern Brazil. The intake of vitamin A and carotenoids from the rice and bean based diet of these children is considered low and appears to influence blood concentrations and liver reserves of this vitamin. With respect to plasma vitamin A, 1.8% of the children had a deficient level (less than 10 micrograms%), whereas 48.8% of the children had a low level (less than 20 micrograms%). Most children with inadequate plasma vitamin A (less than 20 micrograms%) responded positively to a massive dose of 200,000 IU vitamin A, suggesting that these children may be at risk of having low liver stores of vitamin A. Rose Bengal staining test and rapid dark adaptation time did not indicate definite signs of conjunctival xerosis and night blindness among these children. No ocular evidence of hypovitaminosis A was found in the children studied, but marginal or inadequate vitamin A status appears to be a common public health problem among young children in this region of Brazil.

Studies on the bioavailability of zinc in humans: intestinal interaction of tin and zinc.

Mineral/mineral interactions at the intestinal level are important in animal nutrition and toxicology, but only limited understanding of their extent or importance in humans has been developed. An inhibitory interaction of dietary tin on zinc retention has been recently described from human metabolic studies. We have explored the tin/zinc interaction using the change-in-plasma-zinc-concentration method with a standard dosage of 12.5 mg of zinc as zinc sulfate in 100 ml of Coca-Cola. Sn/Zn ratios of 2:1, 4:1, and 8:1, constituted by addition of 25, 50, and 100 mg of tin as stannous chloride, had no significant overall effect on zinc uptake. The 100-mg dose of tin produced noxious gastrointestinal symptoms. Addition of iron as ferrous sulfate to form ratios of Sn/Fe/Zn of 1:1:1 and 2:2:1 with the standard zinc solution and the appropriate doses of tin produced a reduction of zinc absorption not dissimilar from that seen previously with zinc and iron alone, and addition of picolinic acid did not influence the uptake of zinc from the solution with the 2:2:1 Sn/Fe/Zn ratio.

Bioavailability of vitamin A in the rat following ingestion of neomycin sulfate or aluminium hydroxide.

The objective of the present paper was to study the interaction of Neomycin and aluminium hydroxide with vitamin A in terms of the effect of these drugs on the bioavailability of vitamin A in the rat. Bioavailability was determined on the basis of the effects of the drugs on growth and on the plasma and hepatic levels of the vitamin. Vitamin A deficient animals were used in assay 1 and normal animals in assay 2. In each assay the animals were divided into 3 groups: one received Neomycin sulfate (0.1% in the diet), the second received aluminium hydroxide (0.05% in the diet) and the third (control) received no drug. Each of these three groups was subdivided into two groups receiving two different concentrations of vitamin A palmitate. The bioavailability of vitamin A was estimated by the parallel line method from the concentration of vitamin A in the diet and in the liver of the animals. No significant differences in growth or plasma retinol levels were observed between the groups of animals studied in assays 1 and 2. Total vitamin A concentration in the liver of the animals which received Neomycin was lower (p < 0.05) than that observed in the controls. Neomycin reduced the bioavailability of vitamin A by 13.9% (maximum, 18.1% and minimum, 9.6%) in assay 1 and by 13.5% (maximum, 17.7% and minimum, 9.3%) in assay 2. Aluminium hydroxide at the level tested did not affect the bioavailability of vitamin A.

[Plasma zinc levels and the anthropometry of children in the outskirts of urban centers in Brazil]. / Níveis plasmáticos de zinco e antropometria de crianças da periferia de centro urbano no Brasil.

The main objective of the present study was to estimate plasma zinc concentration in children belonging to low-income families residing in three different neighborhoods on the outskirts of Ribeirão Preto, SP, Brazil, and to determine a possible correlation of this parameter with several anthropometric measurements. Plasma zinc levels were lower than 70 micrograms% in 13% of the children studied. Weight for age, height for age and weight/height ratio were below 90% of the 50th percentile of National Center for Health Statistics (NCHS) in 42.9%, 6.3% and 9.5% of children, respectively. Tricipital fold, arm circumference and muscle circumference were also below 90% of the 50th percentile in 65.8%, 11.0% and 7.3% of the children, respectively. No correlation was observed between plasma zinc levels and the anthropometric parameters studied.

Enrichment of the diet with synthetic and natural sources of provitamin A.

The use of available food rich in provitamin A and retinol as well as fortification of local food are known to result in adequate vitamin A status. In Brazil, several regional foods are known to be good sources of provitamin A such as buriti, several palm oils, mango and others. Improving the consumption of these locally available natural sources of provitamin and vitamin A would cover the needs of the vulnerable population. At the same time fortification of industrialized foods with natural and/or synthetic forms of provitamin A could speed up and fill the gap between requirement and low intake of this vitamin in many parts of the country. This approach has been considered by many as the most effective intervention program to prevent micronutrient deficiencies in developing countries. Our previous studies on the subject have shown that cooking vegetable oil, mainly soybean oil, is a very good alternative vehicle to be fortified and supply vitamin A to the population. Lately we have also enriched the same soybean oil with beta-carotene. Addition of this provitamin A to the oil showed it to be stable when heated at cooking and frying temperatures (retention of 92.4 +/- 6.7% and 65.4 +/- 8.6%, respectively). When rat or human food was prepared with carotene-enriched cooking oil, its bioavailability in experimental animals and absorption in humans were shown to be adequate. An alternative for Brazil, besides adding chemical forms of the vitamin to the cooking oil, would be to mix available carotene-rich palm oil to the soybean oil. There are already regional uses of carotenoid-rich palm oils in the preparation of local dishes in some parts of Brazil and this would facilitate its acceptance by the population. Enrichment of common foods in Brazil, such as soybean oil, with chemical forms of beta-carotene or mixing rich sources of provitamin A can be a good alternative to improve the intake of vitamin A by the Brazilian population.

Progress in the diagnosis of hypovitaminosis A: clinical and biochemical correlations.

Hypovitaminosis A is a widespread problem, especially among preschool children in many parts of the world. According to the World Health Organization (WHO) estimates, about 100,000 children become blind every year, and many are dying due to vitamin A deficiency while millions of others are suffering from other consequences of vitamin A deficiency such as growth retardation and increased susceptibility to infection. It is, therefore, very important that not only the severe cases of hypovitaminosis A be diagnosed for immediate treatment, but also the marginal cases of vitamin A deficiency in vulnerable populations be diagnosed as early as possible so that appropriate preventive measures be implemented. Available methods for the diagnosis of vitamin A deficiency can be classified into four categories: clinical, biochemical, functional, and dietary. Clinical diagnosis is based on examining ocular and extraocular signs of hypovitaminosis A, and is only useful for the detection of severe cases. Biochemical methods are based on the plasma concentrations of retinol and retinol-binding protein (RBP), and liver reserve of vitamin A whenever possible. Two other commonly used diagnostic tests are: functional testing for nightblindness using dark adaptation time, and pathological testing for ocular signs of conjunctival xerosis, with or without the use of Rose Bengal or lissamine green dye. Dietary method for the diagnosis of vitamin A deficiency is based on the estimation of dietary intake of vitamin A and carotenoids. In addition, there are newer methods such as isotope dilution and relative dose response (RDR) techniques which have been recently proposed for the diagnosis of vitamin A deficiency. RDR appears to be a reliable and sensitive indicator of marginal vitamin A. However, the most desirable approach to diagnosis may be one based on multiple indicators for the accurate assessment of vitamin A status in the community. The purpose of this paper is to draw attention to the problems of diagnosis, to recent advances and to our Brazilian experience in this important area of vitamin A research with significant global implications.

Long-term type 1 diabetes impairs decidualization and extracellular matrix remodeling during early embryonic development in mice.

INTRODUCTION: Endometrial decidualization and associated extracellular matrix (ECM) remodeling are critical events to the establishment of the maternal-fetal interface and successful pregnancy. Here, we investigated the impact of type 1 diabetes on these processes during early embryonic development, in order to contribute to the understanding of the maternal factors associated to diabetic embryopathies. METHODS: Alloxan-induced diabetic Swiss female mice were bred after different periods of time to determine the effects of diabetes progression on the development of gestational complications. Furthermore, the analyses focused on decidual development as well as mRNA expression, protein deposition and ultrastructural organization of decidual ECM. RESULTS: Decreased number of implantation sites and decidual dimensions were observed in the group mated 90-110 days after diabetes induction (D), but not in the 50-70D group. Picrosirius staining showed augmentation in the fibrillar collagen network in the 90-110D group and, following immunohistochemical examination, that this was associated with increase in types I and V collagens and decrease in type III collagen and collagen-associated proteoglycans biglycan and lumican. qPCR, however, demonstrated that only type I collagen mRNA levels were increased in the diabetic group. Alterations in the molecular ratio among distinct collagen types and proteoglycans were associated with abnormal collagen fibrillogenesis, analyzed by transmission electron microscopy. CONCLUSIONS: Our results support the concept that the development of pregnancy complications is directly related with duration of diabetes (progression of the disease), and that this is a consequence of both systemic factors (i.e. disturbed maternal endocrine-metabolic profile) and uterine factors, including impaired decidualization and ECM remodeling.

The transcription factor Sox2 is required for osteoblast self-renewal.

The development and maintenance of most tissues and organs require the presence of multipotent and unipotent stem cells that have the ability of self-renewal as well as of generating committed, further differentiated cell types. The transcription factor Sox2 is essential for embryonic development and maintains pluripotency and self-renewal in embryonic stem cells. It is expressed in immature osteoblasts/osteoprogenitors in vitro and in vivo and is induced by fibroblast growth factor signaling, which stimulates osteoblast proliferation and inhibits differentiation. Sox2 overexpression can by itself inhibit osteoblast differentiation. To elucidate its function in the osteoblastic lineage, we generated mice with an osteoblast-specific, Cre-mediated knockout of Sox2. These mice are small and osteopenic, and mosaic for Sox2 inactivation. However, culturing calvarial osteoblasts from the mutant mice for 2-3 passages failed to yield any Sox2-null cells. Inactivation of the Sox2 gene by Cre-mediated excision in cultured osteoblasts showed that Sox2-null cells could not survive repeated passage in culture, could not form colonies, and arrested their growth with a senescent phenotype. In addition, expression of Sox2-specific shRNAs in independent osteoblastic cell lines suppressed their proliferative ability. Osteoblasts capable of forming 'osteospheres' are greatly enriched in Sox2 expression. These data identify a novel function for Sox2 in the maintenance of self-renewal in the osteoblastic lineage.

Early postoperative cognitive recovery after remifentanil-propofol or sufentanil-propofol anaesthesia for supratentorial craniotomy: a randomized trial.

BACKGROUND AND OBJECTIVE: This study was designed to evaluate early postoperative cognitive recovery after total intravenous anaesthesia with remifentanil-propofol or sufentanil-propofol in patients undergoing craniotomy for supratentorial expanding lesions. METHODS: Sixty patients were consecutively enrolled, and randomly assigned to one of two study groups: remifentanil-propofol or sufentanil-propofol anaesthesia. To evaluate cognitive function the Short Orientation Memory Concentration Test (SOMCT) and Rancho Los Amigos Scale (RLAS) were administered to all patients in a double-blind procedure before surgery at 15, 45 min and 3 h after extubation. RESULTS: Mean extubation time was similar in the two groups (13 +/- 5 min vs. 19 +/- 6 min). A significantly larger number of patients in the remifentanil-propofol group than in the sufentanil-propofol group required antihypertensive medication postoperatively to maintain mean arterial pressure within 20% of baseline (18/30 vs. 4/29; P = 0.0004). Intergroup analysis showed no differences in baseline SOMCT scores (28 +/- 1 vs. 28 +/- 1) whereas mean SOMCT scores at 15, 45 min and 3 h after extubation were significantly higher in the remifentanil-propofol group (30 patients) than in the sufentanil-propofol group (29 patients) (22 +/- 3 vs. 16 +/- 3; P < 0.0001 and 27 +/- 1 vs. 22 +/- 3; P < 0.0001; 28 +/- 1 vs. 26 +/- 2; P = 0.0126). CONCLUSIONS: In conclusion, propofol-remifentanil and propofol-sufentanil are both suitable for fast-track neuroanaesthesia and provide similar intraoperative haemodynamics, awakening and extubation times. Despite a higher risk of treatable postoperative hypertension propofol-remifentanil allows earlier cognitive recovery.

Assessment of zinc nutritional status of pellagra patients.

The objective of the present study was to assess zinc nutritional status in alcoholic patients with pellagra using plasma, hair, urine and nail zinc levels, as well as the zinc tolerance test. The study was conducted on 81 patients, 73 males and eight females. Zinc parameters were compared with those of 84 individuals with no apparent disease aged 23-45 years. Plasma zinc levels were lower in patients with pellagra than in the controls (P < 0.01). The results of the zinc tolerance test showed that: (1) basal zinc levels were 69.7 +/- 16.8 micrograms/100 ml in pellagrins and 82.3 +/- 34.0 micrograms/100 ml in the controls (P < 0.01); (2) after 1 h the increase in plasma levels was similar in the pellagrin and control groups; (3) during the second hour the increase was more marked in the controls (P < 0.01), and the same was observed during the third and fourth hours (P < 0.05). Urinary zinc excretion (mg/24 h) was higher in pellagrins (P < 0.01). Zinc concentration in hair and toenails did not differ between pellagrins and controls. We conclude that pellagrins present zinc deficiency as demonstrated by plasma and urine zinc levels and by their abnormal response to the zinc tolerance test. We suggest that hair and nail zinc levels should not be used to assess zinc nutritional status in patients with pellagra.

Occurrence of aflatoxins M(1) and M(2) in milk commercialized in Ribeirão Preto-SP, Brazil.

Aflatoxins are toxic metabolites found in foods and feeds. When ruminants eat foodstuffs containing aflatoxins B(1) and B(2), these toxins are metabolized and excreted as aflatoxin M(1) and M(2) in milk. The aim was to determine the incidence of these aflatoxins in commercial milk collected from supermarkets in Ribeirão Preto-SP, Brazil, and consisting of 60 ultrahigh temperature (UHT) milk samples and 79 pasteurized milk samples. The milk samples were analysed according to method 986.16 of AOAC International. None of the milk samples analysed were contaminated with aflatoxin M(2), and aflatoxin M(1) was detected in 29 (20.9%) of samples in the range 50-240 ng l(-1). The results show that despite a high occurrence of aflatoxin M(1) in commercial pasteurized and UHT milk sold in Ribeirão Preto in 1999 and 2000, the contamination level of these toxins could not be considered a serious public health problem according to MERCOSUR Technical Regulations. However, levels in 20.9% of the milk samples exceeded the concentration of 50 ng l(-1) permitted by the European Union. Although it is not necessary to continue monitoring the incidence and levels of aflatoxins M(1) and M(2) in milk samples, surveillance could be appropriate.