Preclinical safety of topically administered nanostructured lipid carriers (NLC) for wound healing application: biodistribution and toxicity studies.

Re-activation of the healing process is a major challenge in the field of chronic wound treatment. For that purpose, lipid-nanoparticles, especially nanostructured lipid carriers (NLC), possess extremely useful characteristics such as biodegradability, biocompatibility and long-term stability, besides being suitable for drug delivery. Moreover, they maintain wound moisture due to their occlusive properties, which have been associated with increased healing rates. In the light of above, NLC have been extensively used topically for wound healing; but to date, there are no safety-preclinical studies concerning such type of application. Thus, in this work, biodistribution studies were performed in rats with the NLC previously developed by our research group, using technetium-99 m (99mTc-NLC) as radiomarker, topically administered on a wound. 99mTc-NLC remained on the wound for 24 h and systemic absorption was not observed after administration. In addition, toxicological studies were performed to assess NLC safety after topical administration. The results obtained demonstrated that NLC were non-cytotoxic, non-sensitizing and non-irritant/corrosive. Overall, it might be concluded that developed NLC remained at the administration area, potentially exerting a local effect, and were safe after topical administration on wounds.

Effects of fasting and gender on ochratoxin A toxicokinetics in F344 rats.

Ochratoxin A (OTA) is a mycotoxin that causes renal tumors in rats, particularly in males. In previous kinetic studies performed in fed conditions (Vettorazzi et al., 2008), mature F344 male rats presented a significantly lower OTA bioavailability than females and young animals. The objective of the present study was to evaluate two factors which could explain this different kinetic profile: the presence of food and the male-specific protein alpha-2u-globulin. Therefore, a 24h kinetic study has been performed in rats under fasting conditions. Food ingestion has been controlled in both sexes during two months. The presence of alpha-2u-globulin in the urine has been analyzed with SDS-gradient mini-gel electrophoresis. Fasting tends to increase the maximum OTA plasma concentrations and the rate of absorption. The relative bioavailability is significantly increased under fasting conditions only in males. Mature males consumed a higher amount of food but, as the OTA dose administered, it was proportional to body weight. The reason why the OTA bioavailability is more affected in presence of food only in males is unclear. Several possibilities, such as differences in gastric emptying, OTA-food interactions and the involvement of alpha-2u-globulin are discussed.

A different kinetic profile of ochratoxin A in mature male rats.

Ochratoxin A (OTA) is a mycotoxin that causes renal tumors in rodents, particularly in male rats. The present work explored the impact of gender and age on OTA toxicokinetics in F344 rats after a single oral dose (0.5mg/kg b.w.). OTA plasma concentrations were analysed with a validated HPLC-FLD method and a population approach (NONMEM VI) was used to perform the kinetic analysis and the one year exposure simulation (0.21 mg/kg daily). Maximum observed OTA concentration (CMAX(obs)) was at 2h in all groups except in mature females (6h). Mature females reached higher CMAX(obs) than males of the same age. Apparent volume of distribution, but not apparent total plasma clearance, increased significantly with body weight (P<0.01) resulting in the following values for the terminal plasma half life (h) in males: 219 (young), 264 (matures) and females: 191 (young), 205 (matures). In addition mature males showed a significant lower relative bioavailability. The simulation showed similar plasma concentrations in males and females after two-months. Thus, toxicokinetic does not seem to explain sex-differences in toxicity in long-term studies. However, the age and weight should be taken into account in short-term toxicological studies if sex-differences are studied.

Ministerio ruso para la Protección Civil, Emergencias y Eliminación de las Consecuencias de los Desastres Naturales (EMERCOM) / No disponible

El campo de las Emergencias es un campo realmentecomplejo en el que intervienen numerosos actores siemprebajo el amparo gubernamental de un país. Aunque con lapalabra emergencias, parece que nos estemos refiriendo almarco sanitario de un evento que requiere una atenciónsanitaria, es un vocablo extensible a todo lo que acontecey pone en peligro la vida humana. Por lo tanto, abarca unespectro mucho más amplio que la asistencia sanitaria,teniendo muchas veces, poco o nada que ver. Esta asistenciaemergente, engloba a su vez varias disciplinas parapaliar, prevenir, combatir y restaurar las consecuenciasocasionadas por alguna situación drástica, y por lo tanto,juega un papel fundamental en la política de un país, en elque va enfocado gran parte de los presupuestos generales yuna gran carga social. En España, está fundamentalmenteenfocado en la Dirección General de Protección Civil,subsidiaria del Ministerio del Interior, mientras que enotros países, constituye de por sí un Ministerio propio. Eneste artículo, se describe precisamente uno de losMinisterios más representativos en cuanto a esta materia ypionero en su funcionamiento, cuyas tácticas han demarcadono sólo las Emergencias en los países del Este, sinoactualmente a nivel internacional. Dicho ministerio es elde las Emergencias y prevención de los desastres ruso, másconocido como EMERCOM(AU)

The field of Emergency is a really complex field thatinvolves many actors always under the umbrella governmentof a country. Although the word emergency, it seemsthat we are referring to the health framework of an eventthat requires immediate attention, is a term extending toeverything that occurs and endangers human life.Therefore covers a much broader spectrum of health care,often having little or nothing to do. This emergency assistance,in turn encompasses several disciplines to mitigate,prevent, combat and restore the consequences caused by adrastic situation, and therefore plays a key role in the politicsof a country, which is largely focused the general budgetand a great social burden. In Spain, is mainly focusedon the General Directorate of Civil Protection, a subsidiaryof the Interior Ministry, while in other countries, isin itself a ministry itself. This article describes just one ofthe most representative ministries regarding this matterand pioneer in its operation, whose tactics have beendemarcated Emergencies not only in countries of the East,but now internationally. This is the ministry of emergenciesand disaster prevention Russian, better known asEMERCOM(AU)

Minimizing creatine kinase variability in rats for neuromuscular research purposes.

Rat serum or plasma creatine kinase (CK) activity is widely used to evaluate myopathic processes, to test the myotoxicity of different drugs, or to analyse the benefits of emerging gene therapies in some neuromuscular disorders. However, great variability is found in this determination. The aim of this study has been to control some factors of variation in order to reduce variability and increase the reproducibility of analytical data. 8-10-week-old Wistar-Han rats were used. The study consisted of four sequential phases. Phase I aimed to analyse the effect of ether and isoflurane as anaesthetic drugs. The objective of Phase II was to evaluate bleeding rats via retro-orbital sinus vs. tail vein. Phases III and IV were designed as two separate, repeated measure experiments on two factors: habituation to laboratory handling procedures in Phase III and gender in Phase IV. The repeated factor was the storage temperature of blood sample prior to centrifugation. Ether did not significantly increased the CK value. Using isoflurane, getting rats accustomed to laboratory handling procedures and whole blood refrigeration prior to centrifugation and serum separation resulted in statistically significant reduction in CK value and variability. Male rats showed significantly higher values than female rats. In the light of our findings, CK value and variability in rats may be minimized by choosing tail vein as site of bleeding, getting rats accustomed to laboratory handling procedures and maintaining whole blood refrigerated until centrifugation and serum separation.

Aplicación de la estrategia secuencial de la OCDE para evaluar la irritación y corrosión dérmica por un producto fitosanitario / Application of the OCDE sequential strategy for the evaluation of dermal irritation and corrosion

Con la intención de reemplazar los ensayos en animales y mejorar las propiedades predictivas, la Guía TG404 de la OCDE sobre irritación/corrosión dérmica aguda ha desarrollado una nueva estrategia secuencial que promueve el uso de métodos alternativos tales como los test en sistemas in vitro. Se ha aplicado el procedimiento de esta estrategia para evaluar la irritación y corrosión dérmica por un nuevo fertilizante con fines de registro, con el objetivo de comprobar sus ventajas en un estudio normalizado. Para evaluar la corrosión dérmica se ha utilizado el sistema in vitro validado EpiDerm™, epidermis reconstituída formada por queratinocitos humanos. Puesto que por el momento no existe un modelo in vitro validado para irritación dérmica, ésta fue evaluada en el sistema EpiDerm™ y mediante un método in vivo. En ambos ensayos in vitro se midió también la liberación de IL1α. El producto fue clasificado como no corrosivo y no irritante. Los resultados del estudio demuestran las ventajas de la estrategia secuencial propuesta por la OCDE en la evaluación de la corrosión e irritación por las siguientes razones: a) se adquiere un conocimiento previo sobre las propiedades físicoquímicas de los compuestos químicos con el fin de evitar la exposición innecesaria de los animales a sustancias corrosivas b) los métodos in vitro de corrosión dérmica pueden sustituir los animales de experimentación c) las modificaciones propuestas para el test in vivo reducen el sufrimiento de los animales y suponen un importante ahorro económico y de tiempo. No obstante, se requiere con urgencia disponer de métodos alternativos in vitro para evaluar la irritación cutánea

In order to replace the assays carried out on animals and improve the predictive properties, the Guideline TG404 of the OCDE on acute dermal corrosion/irritation has developed a new sequential strategy that promotes the use of alternative methods such as the tests in in vitro systems. The procedure of this strategy has been applied in order to evaluate the irritation and dermal corrosion produced by a new fertilizer with the objective of obtaining a patent and in order to determine the advantages of using said fertilizer in a normalized study. In order to evaluate the dermal corrosion, the validated in vitro system EpiDermTM, a reconstituted epidermis formed by human keratinocytes, has been used. Since, at this moment, no in vitro model which is validated for dermal irritation exists, this method was evaluated in the EpiDermTM system and by means of and in vivo method. In both in vivo assays, the release of IL1α was measured also. The product was classified as noncorrosive and nonirritant. The results of the study showed the advantages of the sequential strategy proposed by the OCDE in the evaluation of the corrosion and irritation due to the following reasons: a) prior knowledge is acquired regarding the physicochemical properties of the chemical compounds for the purpose of avoiding unnecessary exposure of corrosive substances to the animals; b) the in vitro methods of dermal corrosion can substitute the experimentation animals and c) the modifications proposed for the in vivo test reduce animal suffering and represent important time and economical savings. However, there is an urgent need for available alternative in vitro methods for the evaluation of cutaneous irritation

Immunotoxic effects of Ochratoxin A in Wistar rats after oral administration.

Ochratoxin A (OTA) is a mycotoxin produced by species of the genus Aspergillus and Penicillium. Human exposure has been demonstrated worldwide and its origin seems to be the intake of contaminated foods. The kidneys are the target organ of this mycotoxin. Immunotoxic and genotoxic effects of OTA were investigated in Wistar male rats (aged 12 weeks), treated by gavage with 50, 150 or 450 microg OTA/kg body weight for 28 days, in the context of a general toxicity study, which was designed following the recommendations of OECD guideline 407. At the end of the study, the mean plasma concentration of the mycotoxin was determined, several immune function assays were performed and bone marrow smears were obtained and stained in order to analyse micronuclei in polychromatic erytrocytes. Mean plasma concentration was found to be 187, 600 and 807 microg/L, respectively. At the highest dose, a decrease in body weight gain was observed. Histopathological investigations revealed tubulonephrosis and acute tubular necrosis in the kidneys of the animals treated with OTA. The frequency and severity of the lesions increased with the dose. The response of splenocytes to sheep red blood cells was decreased in a dose-dependent manner; however, nonstatistically significant differences were obtained. The natural killer cell activity was strongly affected by OTA treatment. Cytotoxic T lymphocyte activity was lower in the animals exposed to 50 microg OTA/kg b.w. but was not modified in the groups exposed to 150 and 450 microg OTA/ kg b.w. The bacteriolytic capability of macrophages was significantly reduced in groups exposed to 50 and 450 microg OTA/ kg b.w. The number of micronuclei in bone marrow polychromatic erytrocytes did not vary significantly with respect to the control at any dose, but a false negative result can not be ruled out because the exposure doses were much lower than those recommended in OECD guideline 474.

A comparative study on the gastroduodenal tolerance of different antianaemic preparations.

The most significant adverse effect of repeated oral administration of iron-containing antianaemic preparations is the gastroduodenal toxicity, attributable to a direct toxic effect of iron on the glandular epithelium. To assess gastroduodenal mucosal damage and the potential protective effect of different antianaemic preparations, a study was carried out to compare the gastroduodenal toxicity caused by three different types of antianaemic drugs in normal and anaemic rats administered at repeated therapeutic doses. Histological damage to the gastroduodenal mucosa was evaluated using light and electron microscopy. In both normal and anaemic rats, pathological changes were less marked in animals treated with ferrimannitol-ovoalbumin (TM/FMOA) than in those treated with iron protein succinylate or ferrous sulphate. Electron microscopic studies of duodenal mucosa in normal rats treated with iron protein succinylate and ferrous sulphate confirmed a severe ultrastructural alteration, whereas no changes were detected in animals treated with TM/FMOA. In anaemic rats, slight duodenal ultrastructural changes were noted with all three types of treatment. The effectiveness of the preparations in resolving the anaemia was similar in the three groups. It was concluded that TM/FMOA exerts a protective effect against the toxicity normally observed of the iron in other formulations in normal and anaemic rats, which was attributed to the fact that administration of iron bound to a protein core allows for gradual release of iron.

Liver damage using suicide genes. A model for oval cell activation.

Liver regeneration from the facultative hepatic stem cells, the oval cells, takes place in situations in which liver regeneration from pre-existing hepatocytes is prevented. Different models have been used to stimulate oval cell response. Many of them involve the use of carcinogenic agents with or without partial hepatectomy. In this study we show that adenovirus-mediated gene transfer of the suicide gene thymidine kinase followed by ganciclovir administration caused hepatotoxicity of variable intensity. Rats with moderate elevation in serum transaminases recovered normal liver architecture few weeks after adenovirus injection. In contrast, rats with severe liver damage exhibited a marked and persisting activation of oval cells accompanied by ductular hyperplasia. In some rats, such lesion eventually evolved to cholangiofibrosis and in one rat to cholangiocarcinoma. Deposition of fibronectin and increased number of hepatic stellate cells were found in association with oval cells and cholangiofibrotic lesions. Hepatocyte growth factor was hyperexpressed in the livers with intense oval cell response or ductular proliferation, suggesting a participation of this factor in those lesions. In summary, our data demonstrate activation of oval cell response after gene transfer of thymidine kinase followed by ganciclovir administration. These findings indicate that high doses of this therapy causes liver damage together with an impairment in hepatocellular regeneration.

The impact of Hurricane Andrew on deviant behavior among a multi-racial/ethnic sample of adolescents in Dade County, Florida: a longitudinal analysis.

Findings from a longitudinal study are presented on the relationships between the problems and stresses resulting from Hurricane Andrew and posthurricane minor deviant behavior. The sample (N = 4,978) included Hispanic, African-American, and White non-Hispanic middle school students enrolled in Dade County, Florida public schools. Two waves of data were collected prior to the hurricane; a third was obtained approximately 6 months following the storm. Results indicated that females were likely to report higher levels of hurricane-related stress symptoms than males. After controlling for prehurricane levels of minor deviance, family support, and race/ethnicity, hurricane stress symptom level remained a significant predictor of posthurricane minor deviant behavior. The findings lend support to stress theories of social deviance.

Disaster related stresses, depressive signs and symptoms, and suicidal ideation among a multi-racial/ethnic sample of adolescents: a longitudinal analysis.

Longitudinal findings are presented on the relationships between disaster related stresses, depression scores, and suicidal ideation among a multi-racial/ethnic sample of adolescents (N = 4,978) all of whom have been exposed to Hurricane Andrew. Regression analysis showed that being female, hurricane generated stresses, low levels of family support, pre-hurricane suicidal ideation, and post-hurricane depression scores were significant predictors of post-hurricane suicidal ideation. Path analysis revealed that being female, low socioeconomic status, pre- and post-hurricane depression, high stress scores, low family support, and pre-hurricane suicidal ideation had significant direct/indirect effects on post-hurricane suicidal ideation.

A replication and elaboration of the esteem-enhancement model.

Adolescents treated in clinical settings for drug use problems are often observed to have low self-esteem. This has led some researchers to the belief that mood or personality characteristics of adolescents predispose them to drug use. However, longitudinal field studies have failed to confirm a direct relationship between low self-esteem and substance abuse (Petraitis et al. 1995). Evidently, if an important causal relationship exists between self-esteem and drug use in the nonclinical adolescent population, it is complex and mediated by other factors. To address this issue, explanatory theories are needed that can organize the relationships between drug abuse and its antecendent causes including low self-esteem. One of the few theoretical approaches that has been put forward for empirical verification is the esteem-enhancement theory of Kaplan, Johnson, and Bailey (1986a, 1987, 1988).

Gender and ethnic differences in the prevalence of alcohol, cigarette, and illicit drug use over time in a cohort of young Hispanic adolescents in south Florida.

The purpose of this study was to describe patterns of substance use among young Hispanic adolescents of Cuban and Central/South American heritage, many of whom are recent immigrants to the U.S. At present there are very little epidemiologic data on these Hispanic ethnic subgroups, particularly for girls. A cohort of 848 middle school boys and girls in Miami, Florida completed questionnaires in 7th, 8th, and 9th grades concerning their use of alcohol, cigarettes, marijuana, and other illicit drugs. African Americans and White non-Hispanics were used as comparison groups. In general, White non-Hispanics and U.S.-born Hispanics had the highest lifetime and past year prevalence rates of substance use. While no statistically significant gender differences were found for any of the racial/ethnic groups, the use of substances among Hispanic girls often exceeded that of their male counterparts. A progressive increase in use of alcohol, cigarettes, marijuana, and other illicit drugs was evident over the two and one-half year duration of the study for both gender groups.

Teacher and parent perceptions of behavior problems among a sample of African American, Hispanic, and non-Hispanic white students.

A multiracial/multiethnic sample of middle school adolescents and their teachers was used to assess whether teacher ratings of student behavior problems varied according to teacher-student racial/ethnic differences and students' perception of teachers' attitudes toward them. No significant mean score differences were found for Hispanic or non-Hispanic white students according to the race/ethnicity of the teachers doing the ratings. However, African American students rated by Hispanic and non-Hispanic white teachers had significantly higher mean total behavior problem scores than African American students rated by African American teachers. Teacher ratings were also compared to those made by parents. The percentage of students rated as cases by teachers but not by parents differed significantly by race/ethnicity of student. Other findings indicated highly significant relationships between student-perceived teacher disparagement and the assignment of high behavior problem scores to students by teachers.

Self-rejection/derogation, peer factors, and alcohol, drug, and cigarette use among a sample of Hispanic, African-American, and white non-Hispanic adolescents.

Data from the first two waves of a longitudinal study are reported on the relationships between self-rejection/derogation and substance use among a multiracial/ethnic sample of adolescents (N = 4,983). Significant increases were found for all three groups between Waves 1 and 2. African-Americans had the lowest rates at both time periods. Peer factors, rejection/derogation, and race/ethnicity were significant predictors of alcohol and cigarette use but not of illicit drug use. Peer factors were more powerful predictors of substance use than rejection/derogation. Interaction analyses indicated peer and rejection/derogation factors were independent predictors of substance use.

Who is Hispanic? Definitions and their consequences.

What is the appropriate method for classifying Spanish-speaking-origin inhabitants of the United States? This paper presents relevant data from the first wave of a longitudinal study of adolescents in the greater Miami area. As expected, the broadest definition--"up to third generation" Hispanic--identified the largest proportion of the sample as Hispanic, whereas parent self-report placed the smallest proportion into the Hispanic category. When policymakers are concerned about enumerating the entire Hispanic population, a definition broader than self-identification should be used; in estimating prevalence rates, however, the use of self-identification may be adequate.

Acculturation and delinquent behavior among Cuban American adolescents: toward an empirical model.

Uses data derived from a study of 6th- and 7th-grade Cuban American adolescents in the greater Miami, Florida, area. The effects of immigrant cultural adjustment on the behavior of adolescents, especially deviant behavior, has been a subject of interest for decades. However, heretofore, little empirical research has been conducted. Key findings indicate that family factors are related to the development of attitudes favoring deviance, whereas acculturation conflicts are associated with delinquent behavior. Results are considered tentative but important for developing a comprehensive and theoretically grounded model of factors contributing to deviant behavior among Hispanic adolescents.

Risk factors for early adolescent drug use in four ethnic and racial groups.

OBJECTIVES: It is widely believed that risk factors identified in previous epidemiologic studies accurately predict adolescent drug use. Comparative studies are needed to determine how risk factors vary in prevalence, distribution, sensitivity, and pattern across the major US ethnic/racial groups. METHODS: Baseline questionnaire data from a 3-year epidemiologic study of early adolescent development and drug use were used to conduct bivariate and multivariate risk factor analyses. Respondents (n = 6760) were sixth- and seventh-grade Cuban, other Hispanic, Black, and White non-Hispanic boys in the 48 middle schools of the greater Miami (Dade County) area. RESULTS: Findings indicate 5% lifetime illicit drug use, 4% lifetime inhalant use, 37% lifetime alcohol use, and 21% lifetime tobacco use, with important intergroup differences. Monotonic relationships were found between 10 risk factors and alcohol and illicit drug use. Individual risk factors were distributed disproportionately, and sensitivity and patterning of risk factors varied widely by ethnic/racial subsample. CONCLUSIONS: While the cumulative prevalence of risk factors bears a monotonic relationship to drug use, ethnic/racial differences in risk factor profiles, especially for Blacks, suggest differential predictive value based on cultural differences.

Patterns of drug use among Cuban-American, African-American, and white non-Hispanic boys.

This study examined initiation into drug use during grade school years in a sample of Cuban-American, Black, and White non-Hispanic students in the greater Miami, Fla, area. Findings indicate that first use of alcohol occurs in fifth grade and cigarettes in sixth grade for all subgroups except White non-Hispanics, who peak in the fifth grade. White non-Hispanics had the highest life-time levels of alcohol and cigarette use. Foreign-born Cuban Americans had a lower lifetime prevalence of alcohol and cigarette use than US-born Cuban Americans. Higher acculturation level was related to first use of alcohol. One important implication of this study is that alcohol interventions should begin no later than third grade and smoking interventions no later than fourth grade.