Cross Determination of Exciton Coherence Length in J-Aggregates.

The coherence length of the Frenkel excitons (Ncoh) is one of the most critical parameters governing many key features of supramolecular J-aggregates. Determining experimentally the value of Ncoh is a nontrivial task since it is sensitive to the technique/method applied, causing discrepancies in the literature data even for the same chemical compound and aggregation conditions. By using a combination of different experimental techniques including UV-vis-NIR, fluorescence emission, time-resolved photoluminescence, and transient absorption spectroscopies, we determined Ncoh values for J-aggregates of a cyanine dye. We found that the absorption spectroscopy alone - a widely used technique- fails in determining right value for Ncoh. The correct approach is based on the modification of photoluminescence lifetime and nonlinear response upon aggregation and careful analysis of the Stokes shift and electron-phonon coupling strength. This approach revealed that Ncoh of JC-1 J-aggregates ranges from 3 to 6.

Dielectric spectroscopy of novel bio-based aliphatic-aromatic block copolymers: Poly(butylene terephthalate)-b-poly(lactic acid).

Broadband dielectric spectroscopy has been used to characterize in deep the relaxation behavior of novel bio-based aliphatic-aromatic block copolymers based on poly(butylene terephthalate) (PBT) and poly(lactic acid) (PLA). The results indicate that the copolymerization decreases the ability to crystallize of the resulting block copolymer. The [Formula: see text] relaxation of the block copolymers is consistent with this fact exhibiting initially the characteristics features of an amorphous polymeric material cold crystallizing upon heating. The cold crystallization can be easily visualized by dielectric spectroscopy by a discontinuous and abrupt change of the shape parameters of the [Formula: see text] relaxation. The sub-glass dynamics of the block copolymers is complex and be ascribed to a [Formula: see text] relaxation composed of two local modes, [Formula: see text] and [Formula: see text], which can be assigned to the relaxation in PBT of the bond between the ester oxygen and the aliphatic carbon and to the bond between the aromatic ring carbon to the ester carbon, respectively. With increasing amount of the PLA block the crystallinity decreases as well as the activation energy of the [Formula: see text] mode approaching the expected value for amorphous PBT. On the contrary, the activation energy for the [Formula: see text] exhibits an unexpected increase as the amount of PLA increases. This effect has been explained by considering that at lower temperatures the [Formula: see text] mode of PBT is the more significant while at higher temperatures the [Formula: see text] relaxation of the PLA block becomes the dominant one.

Immunomodulatory tetracyclines shape the intestinal inflammatory response inducing mucosal healing and resolution.

BACKGROUND AND PURPOSE: Immunomodulatory tetracyclines are well-characterized drugs with a pharmacological potential beyond their antibiotic properties. Specifically, minocycline and doxycycline have shown beneficial effects in experimental colitis, although pro-inflammatory actions have also been described in macrophages. Therefore, we aimed to characterize the mechanism behind their effect in acute intestinal inflammation. EXPERIMENTAL APPROACH: A comparative pharmacological study was initially used to elucidate the most relevant actions of immunomodulatory tetracyclines: doxycycline, minocycline and tigecycline; other antibiotic or immunomodulatory drugs were assessed in bone marrow-derived macrophages and in dextran sodium sulfate (DSS)-induced mouse colitis, where different barrier markers, inflammatory mediators, microRNAs, TLRs, and the gut microbiota composition were evaluated. The sequential immune events that mediate the intestinal anti-inflammatory effect of minocycline in DSS-colitis were then characterized. KEY RESULTS: Novel immunomodulatory activity of tetracyclines was identifed; they potentiated the innate immune response and enhanced resolution of inflammation. This is also the first report describing the intestinal anti-inflammatory effect of tigecycline. A minor therapeutic benefit seems to derive from their antibiotic properties. Conversely, immunomodulatory tetracyclines potentiated macrophage cytokine release in vitro, and while improving mucosal recovery in colitic mice, they up-regulated Ccl2, miR-142, miR-375 and Tlr4. In particular, minocycline initially enhanced IL-1ß, IL-6, IL-22, GM-CSF and IL-4 colonic production and monocyte recruitment to the intestine, subsequently increasing Ly6C- MHCII+ macrophages, Tregs and type 2 intestinal immune responses. CONCLUSIONS AND IMPLICATIONS: Immunomodulatory tetracyclines potentiate protective immune pathways leading to mucosal healing and resolution, representing a promising drug reposition strategy for the treatment of intestinal inflammation.

Immunomodulatory tetracyclines ameliorate DNBS-colitis: Impact on microRNA expression and microbiota composition.

OBJECTIVE: The use of immunomodulatory antibiotics to simultaneously target different factors involved in intestinal inflammatory conditions is an interesting but understudied pharmacological strategy. A great therapeutic potential has been obtained with minocycline and doxycycline in experimental colitis. Therefore, understanding the contribution of the different activities of immunomodulatory tetracyclines is crucial for the improvement and translation of their use into clinic. DESIGN: A comparative pharmacological study including tetracyclines and other antibiotic or immunomodulatory drugs was performed in 2,4-dinitrobenzene sulfonic acid (DNBS)-induced colitis in mice. The correlation between the therapeutic efficacy of each drug and changes in the gut microbiota composition, markers of barrier integrity, inflammatory mediators, microRNAs and TLRs was analysed to identify the main mechanisms of action. RESULTS: Tetracyclines counteracted most of the markers found altered in DNBS-colitis, which differed from effects of corticosteroid treatment. Of note, administration of tetracyclines led to increased mucosal protection, associated with up-regulated expression of CCL2, miR-142 and miR-375. All drugs with antibiotic activity ameliorated the progression of inflammation and reduced neutrophil-related genes, such as miR-223, despite their effects were not associated with restored intestinal dysbiosis. However, reduced bacterial richness was correlated with increased expression of TLR2 and TLR9 in antibiotic-treated groups and TLR6 was also up-regulated by the immunomodulatory tetracyclines with higher efficacy (doxycycline, minocycline and tigecycline). CONCLUSION: The anti-inflammatory effect of tetracyclines involves specific modifications in TLR and microRNA expression leading to an improved microbial-derived signalling and mucosal protection. These results support the potential of immunomodulatory tetracyclines to prevent inflammation-associated tissue damage in acute intestinal inflammation.

Effect of chemical structure on the subglass relaxation dynamics of biobased polyesters as revealed by dielectric spectroscopy: 2,5-furandicarboxylic acid vs. trans-1,4-cyclohexanedicarboxylic acid.

The chemical structure-dynamics relationship for poly(trimethylene 2,5-furanoate) and poly(trimethylene 1,4-cyclohexanedicarboxylate) was investigated via dielectric spectroscopy and compared with that of poly(trimethylene terephthalate) in order to evaluate the impact on the subglass dynamics of the chemical nature of the ring. Further comparison was accomplished with the neopentyl glycol containing counterparts: poly(neopentyl 2,5-furanoate) and poly(neopentyl 1,4-cyclohexanedicarboxylate). Our study reveals a multimodal nature of the subglass ß process. For the more flexible polymers (containing cyclohexane rings) three modes for the ß process were detected. The faster mode was assigned to the relaxation of the oxygen linked to the aliphatic carbon, the slower one to the link between the aliphatic ring and the ester group, and the third mode to the aliphatic ring. For stiffer polymers (containing aromatic rings), the local modes appear more coupled. This effect is more evident in the polymers with the furan ring where essentially a single ß mode can be resolved.

Mammalian Adaptation of an Avian Influenza A Virus Involves Stepwise Changes in NS1.

Influenza A viruses (IAVs) are common pathogens of birds that occasionally establish endemic infections in mammals. The processes and mechanisms that result in IAV mammalian adaptation are poorly understood. The viral nonstructural 1 (NS1) protein counteracts the interferon (IFN) response, a central component of the host species barrier. We characterized the NS1 proteins of equine influenza virus (EIV), a mammalian IAV lineage of avian origin. We showed that evolutionarily distinct NS1 proteins counteract the IFN response using different and mutually exclusive mechanisms: while the NS1 proteins of early EIVs block general gene expression by binding to cellular polyadenylation-specific factor 30 (CPSF30), NS1 proteins from more evolved EIVs specifically block the induction of IFN-stimulated genes by interfering with the JAK/STAT pathway. These contrasting anti-IFN strategies are associated with two mutations that appeared sequentially and were rapidly selected for during EIV evolution, highlighting the importance of evolutionary processes in immune evasion mechanisms during IAV adaptation.IMPORTANCE Influenza A viruses (IAVs) infect certain avian reservoir species and occasionally transfer to and cause epidemics of infections in some mammalian hosts. However, the processes by which IAVs gain the ability to efficiently infect and transmit in mammals remain unclear. H3N8 equine influenza virus (EIV) is an avian-origin virus that successfully established a new lineage in horses in the early 1960s and is currently circulating worldwide in the equine population. Here, we analyzed the molecular evolution of the virulence factor nonstructural protein 1 (NS1) and show that NS1 proteins from different time periods after EIV emergence counteract the host innate immune response using contrasting strategies, which are associated with two mutations that appeared sequentially during EIV evolution. The results shown here indicate that the interplay between virus evolution and immune evasion plays a key role in IAV mammalian adaptation.

Fish cell lines as a tool for the ecotoxicity assessment and ranking of engineered nanomaterials.

Risk assessment of engineered nanomaterials (ENMs) is being hindered by the sheer production volume of these materials. In this regard, the grouping and ranking of ENMs appears as a promising strategy. Here we sought to evaluate the usefulness of in vitro systems based on fish cell lines for ranking a set of ENMs on the basis of their cytotoxicity. We used the topminnow (Poeciliopsis lucida) liver cell line (PLHC-1) and the rainbow trout (Oncorhynchus mykiss) fibroblast-like gonadal cell line (RTG-2). ENMs were obtained from the EU Joint Research Centre repository. The size frequency distribution of ENM suspensions in cell culture media was characterized. Cytotoxicity was evaluated after 24 h of exposure. PLHC-1 cells exhibited higher sensitivity to the ENMs than RTG-2 cells. ZnO-NM was found to exert toxicity mainly by altering lysosome function and metabolic activity, while multi-walled carbon nanotubes (MWCNTs) caused plasma membrane disruption at high concentrations. The hazard ranking for toxicity (ZnO-NM > MWCNT ≥ CeO2-NM = SiO2-NM) was inversely related to the ranking in size detected in culture medium. Our findings reveal the suitability of fish cell lines for establishing hazard rankings of ENMs in the framework of integrated approaches to testing and assessment.

Effects of a silver nanomaterial on cellular organelles and time course of oxidative stress in a fish cell line (PLHC-1).

Among the nanomaterials currently in commercial products, those based on silver are the most used, and so there is a high probability that silver nanoparticles (AgNPs) will be released into aquatic environments where they could adversely affect aquatic organisms, including fish. Taking this into account, the aim of the present work was to characterize in depth the mechanisms underlying the toxic action of AgNPs using fish cell lines, determining specifically the contribution of alterations in cellular structures and oxidative stress time course to the cytotoxicity of AgNPs. Since liver plays a key role in detoxification, the hepatoma cell line PLHC-1 was used. Exposure to AgNPs (NM-300K, obtained from the Joint Research Centre Repository) caused alterations at the lysosomal and mitochondrial levels at lower concentrations than those that disrupted plasma membrane (evaluated by means of neutral red, alamarBlue, and 5-carboxyfluorescein diacetate, acetoxymethyl ester assays respectively). AgNO3, used as a control Ag+ ion source, produced similar cytotoxic effects but at lower concentrations than AgNPs. Both silver forms caused oxidative disruption but the initial response was delayed in AgNPs until 6h of exposure. Transmission electron microscopy analysis also evidenced the disruption of mitochondrial structures in cells exposed to cytotoxic concentrations of both forms of silver. At non-cytotoxic concentrations, AgNPs were detected inside the nucleoli and mitochondria, thereby pointing to long-term effects. The present work evidences the mutual interaction between the induction of oxidative stress and the alterations of cellular structures, particularly mitochondria, as cytotoxicity mechanisms not exclusively associated to NPs.

Effect of aqueous and particulate silk fibroin in a rat model of experimental colitis.

Silk fibroin (SF) has anti-inflammatory properties and promotes wound healing. Moreover, SF particles act as carriers of active drugs against intestinal inflammation due to their capacity to deliver the compound to the damaged colonic tissue. The present work assesses the effect of SF in the trinitrobenzenesulfonic acid model of rat colitis that resembles human intestinal inflammation. SF (8mg/kg) was administered in aqueous solution orally and in two particulate formats by intrarectal route, following two technologies: spray drying to make microparticles and desolvation in organic solvent to produce nanoparticles. SF treatments ameliorated the colonic damage, reduced neutrophil infiltration and improved the compromised oxidative status of the colon. They also reduced the gene expression of pro-inflammatory cytokines like IL-1ß and the anti-inflammatory cytokine IL-10. Moreover, they improved the intestinal wall integrity by increasing the gene expression of some of its markers (villin, trefoil factor-3 and mucins), thus accelerating the healing. The immunomodulatory properties of SF particles were also tested in vitro in macrophages: they activated the immune response in basal conditions without increasing it after a pro-inflammatory insult. In conclusion, SF particles could be useful as carriers to deliver active drugs to the damaged intestinal colon with additional anti-inflammatory and healing properties.

Intestinal anti-inflammatory activity of calcium pyruvate in the TNBS model of rat colitis: Comparison with ethyl pyruvate.

Pyruvate is a key intermediate of the carbohydrate metabolism with endogenous scavenger properties. However, it cannot be used in clinics due to its instability. Ethyl pyruvate (EP) has shown better stability as well as an antioxidant and anti-inflammatory activity. Calcium pyruvate monohydrate (CPM) is another stable pyruvate derivative that could also provide the benefits from calcium, fundamental for bone health. Considering everything, we propose CPM as a therapeutic strategy to treat diseases with an immune component in which there is also a significant dysregulation of the skeletal homeostasis. This could be applicable to inflammatory bowel disease, which is characterized by over-production of pro-inflammatory mediators, including cytokines and reactive oxygen and nitrogen metabolites that induces intestinal mucosal damage and chronic inflammation, and extra-intestinal symptoms like osteopenia and osteoporosis. The effects of CPM and EP (20, 40 and 100mg/kg) were evaluated on the trinitrobenzenesulfonic acid (TNBS) model of colitis in rats, after a 7-day oral treatment, with main focus on colonic histology and inflammatory mediators. Both pyruvates showed intestinal anti-inflammatory effects in the TNBS-induced colitis. They were evident both histologically, with a recovery of the mucosal cytoarchitecture and a reduction of the neutrophil infiltration, and through the profile of inflammatory mediators (IL-1, IL-6, IL-17, IL-23, iNOS). However, CPM appeared to be more effective than ethyl pyruvate. In conclusion, CPM exerts intestinal anti-inflammatory effect on the TNBS-induced colitis in rats, although further experiments are needed to explore its beneficial effects on bone health and osteoporosis.

Structure and morphology of thin films of linear aliphatic polyesters prepared by spin-coating.

Thin films, with thicknesses from 10 to 400 nm of linear aliphatic polyesters (X, Y), based on propylenediol (X = 3) and on dicarboxylic acid of different chain length (Y = 2, 3, and 4 CH(2) units) were prepared by spin coating of CHCl(3) polymer solutions with different polymer concentrations. Morphology and structure of the spin coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence X-ray scattering techniques at small, (GISAXS) and wide angles (GIWAXS). AFM revealed a strong dewetting for all three polymers for coatings thinner than 100 nm. The polymer films are clearly semicrystalline for thicknesses higher than 50 nm. GIWAXS of the thicker films revealed their oriented crystalline nature. An edge-on-lamellae morphology is clearly shown by the AFM-phase images even for relatively thin films. SAXS with the beam parallel to the sample plane also support the presence of lamellae perpendicular to the substrate. The use of a mu-beam helped to interpret the GIWAXS patterns and allowed to obtain oriented WAXS patterns from melt solidified filaments. Thus, a crystal chain packing is proposed for the three polymers and consequently the indexing of the observed reflections. Accordingly, the polymer chains lie parallel to the substrate being the bc plane of the monoclinic crystal unit cell parallel to the substrate.

The impact of telemedicine on quality of life in rural areas: the Extremadura model of specialized care delivery.

BACKGROUND: Referrals from rural health centers to urban hospitals join waiting lists as outpatients for hospital admission and hospital treatment. This influences quality of life (QoL) of the rural population and retired people who require medical attention without traveling, provided no risks are involved. For this reason, a rural region of Spain has adopted a strategy to deliver telemedicine (TM) specialized care (Extremadura model) as a political decision. OBJECTIVES: The present study aimed at objectively assessing QoL on aspects of health and well-being for citizens benefiting from this system. METHODS: We performed a randomized study of 800 primary care patients referred for specialized care: 420 regular face-to-face hospital referrals and 380 referred to a hospital specialist at a distance by TM. The study used two questionnaires: a modified version of the classical SF-12v2 short form questionnaire for health and well-being and a specific author-elaborated questionnaire. The latter focused on major patient concerns such as (1) discomfort and pain relief, (2) swift diagnosis, (3) swift treatment, (4) swift decision on hospital admission or not, (5) avoidance of traveling, (6) avoidance of red tape, and (7) personal attention. QoL was assessed twice: before referral to a hospital specialist and 6 months after referral to the same. The results were statistically compared. RESULTS: Both groups showed comparable health status with added advantages for TM referrals such as (1) less traveling (p = 0.0001) and (2) faster diagnosis, health examination, and treatment (p = 0.0001). CONCLUSION: Telemedicine care by a hospital specialist through videoconferencing was comparable to hospital referral for face-to-face medicine. Teleconsultations managed by nurses had a positive impact on the QoL of rural patients. They did not have to travel and thus diagnoses and examinations to start treatment were initiated faster.

Evidence of early stage precursors of polymer crystals by dielectric spectroscopy.

Dielectric spectra of the polyester poly(propylene succinate) were measured upon crystallization. For this model aliphatic polyester the alpha and beta relaxations appear simultaneously and are well resolved in the experimental frequency window. During isothermal crystallization, this fact allows one to use the beta relaxation to characterize the crystalline structural development while the alpha relaxation provides information about the evolution of the amorphous phase dynamics. In this way structure development and dynamics evolution can be characterized by a single experiment during the crystallization process. The unambiguous analysis of the dielectric loss clearly supports the existence of precursors of crystallization in the induction period.

Confined crystallization in phase-separated poly(ethylene terephthalate)/poly(ethylene naphthalene 2,6-dicarboxilate) blends.

The isothermal cold crystallization of poly(ethylene terephthalate)(PET) in cryogenic mechanical alloyed blends of PET and Poly(ethylene naphthalene 2,6-dicarboxilate)(PEN) 1:1 by weight has been investigated by simultaneous small and wide angle X-ray scattering (SAXS and WAXS) and dielectric spectroscopy (DS). For transesterification levels higher than 23% the blends tend to transform into a one-phase system and the crystallization of PET is strongly inhibited due to the significant reduction of the PET segment length. For lower levels of transesterification the blends are phase separated and the overall crystallization behaviour can be explained considering the confined nature of the PET domains in these blends. The formation of a rigid amorphous phase in the intra-lamellar stack amorphous regions is reduced in the blends due to a lower probability of stack formation in the confined PET-rich domains. The more effective filling of the space by the lamellar crystals in the blends provokes a stronger restriction to the amorphous phase mobility of PET in the blends than in pure PET.

Epistatic effects occurring among susceptibility and protective MHC genes in IgA deficiency.

Immunoglobulin A deficiency (IgAD), the most prevalent primary immunodeficiency in Caucasian populations, shows strong evidence of polygenic inheritance with several associated genes being located in the major histocompatibility complex (MHC). Our aims were to determine which previously described MHC associations were primary and not secondary to a decrease or an increase in other MHC haplotype frequencies, to study the genetic interactions between all disease-associated MHC haplotypes and, finally, to ascertain the relative importance of protection vs susceptibility. A relative predispositional effect (RPE) study showed that in addition to the primary positive association of IgAD with HLA-DRB1*0102, DR3/TNFa2b3, and DR7 carrying haplotypes, DRB1*1501 was a marker of a primary protective factor in the Spanish population. Our data also indicate that the combined presence in an individual of two MHC susceptibility haplotypes notably increases the predisposition to the disease and that DRB1*1501 positive haplotypes eliminate the susceptibility conferred by any other MHC haplotype.

Two new mutations in cis on (G)gamma chain of fetal hemoglobin: Hb F-Madrid [G gamma 50(D1)Ser-->Cys] and [G gamma 75(E19)Ile-->Thr].

We describe a new structural hemoglobin variant of (G)gamma with two amino acid replacements in cis found in the umbilical cord blood of a neonate in Madrid, Spain. The substitutions were identified on exon 2 of the (G)gamma globin gene, at codon 50 (T CT-->T GT) and at codon 75 (A TA-->A CA). We have named it Hb F-Madrid. The father of the propositus was the carrier of the same (G)gamma chain variant and, moreover, molecular study of alpha genes revealed the loss of an alpha gene (-alpha(3.7)/alpha alpha) both in the propositus and his mother.

Influence of estradiol and gestagens on oxidative stress in the rat uterus.

OBJECTIVE: We studied the effect of ovariectomy, estradiol (E2), and E2 + medroxyprogesterone (MPA) on the Wistar rat uterus. METHODS: We used 15 adult female rats. The study was divided into the following four stages: (a) extirpation of the upper half of the left hemi-uterus (basal state) and ovariectomy; (b) animals were maintained for 15 days without treatment, performance of a new laparotomy, and extirpation of the remaining left hemi-uterus (OVX state); (c) beginning of E2 replacement therapy (ERT) (8 microg/day) for 15 days, followed by extirpation of the upper half of the right hemi-uterus (ERT state); and (d) the administration of E2 was continued, and oral treatment with MPA was begun (20 microg/day) to last for a further 15 days. At the end of the combined hormone replacement therapy (HRT) the remaining right hemi-uterus was extirpated (HRT state). At the end of each intervention, the plasma concentrations of E2 and PRG were measured. RESULTS AND DISCUSSION: The ovariectomy significantly reduced the malonaldehyde (MDA) levels (P < 0.0008) and catalase activity (P < 0.0006). The ERT very significantly (P < 0.0033) raised the catalase and MDA levels; these significance levels were maintained after the Bonferroni method was applied (overall error 5%). The HRT reduced the levels of MDA and catalase, but not significantly after the Bonferroni test was applied.Conclusions. Uterine oxidative stress is increased by E2, resulting in a significant increase in MDA. This may be modulated in part by the catalase activity. Although it cannot be confirmed categorically, MPA seems to intervene by decreasing the said oxidative stress.

On the relationship between crystalline structure and amorphous phase dynamics during isothermal crystallization of bacterial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymers.

The isothermal crystallization process of a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer, P(HB-co-HV) with a HB/HV ratio 78/22 was investigated by simultaneous small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and dielectric spectroscopy (DS). By use of this experimental setup (SWD), we have obtained simultaneous information about changes occurring in both the crystalline and the amorphous phases during crystallization. By using the Havriliak-Negami formalism to analyze the dielectric relaxation data, a strong dependence of the relaxation curve shape with the development of the crystalline phase was found. However, in this particular copolymer, the developing crystalline domains do not affect significantly the average segmental mobility in the amorphous phase. This effect is discussed in the light of the enrichment of amorphous phase by HV comonomer units during primary crystallization, hindering the secondary crystallization processes. Results support the hypothesis that the decrease of the physical-aging-like behavior, observed in P(HB-co-HV) copolymers as the amount of HV increases, can be attributed to the progressive inhibition of secondary crystallization mechanisms.

Influence of estrogen replacement therapy on plasma lipid peroxidation.

OBJECTIVE: To observe whether any relationship exists between the concentration of plasma estradiol (E2) and the plasma concentrations of malondialdehyde (MDA) or whether a relationship exists between the concentration of plasma E2 and the activity of the erythrocyte enzymes, superoxide dismutase (SOD) and catalase, in ovariectomized female Wistar rats (treated and untreated with E2). DESIGN: We used 40 ovariectomized Wistar rats randomly assigned to four groups. The first group was allowed to evolve freely with no treatment. A gel containing 17beta-estradiol was administered transdermally to the other three groups at doses of 4, 8, and 16 microg/day, respectively. After 15 days of treatment, blood samples were obtained from the four groups. The concentrations of plasma MDA and E2 and the activities of erythrocyte catalase and SOD were determined. RESULTS: There were significant correlations between the MDA levels and the logarithm (base 10) of the plasma E2 concentrations in both linear (p = 0.00093) and quadratic (p = 0.000001) regression analyses. No relationship was found between the E2 concentrations and the catalase and SOD activities. CONCLUSIONS: There was a clear relationship between the plasma levels of MDA and the logarithm of the plasma E2 concentrations, which was best demonstrated with a quadratic regression. This model may explain the contradictory findings presented by estrogens with respect to their pro-or antioxidant action.

Influence of estradiol on oxidative stress in the castrated rat uterus.

OBJECTIVE: We set out to study how the concentration of estradiol influences oxidative stress (malondialdehyde) and the superoxide dismutase and catalase antioxidant systems in the castrated female Wistar rat uterus. METHODS: We used 28 castrated female Wistar rats: 7 were left to evolve freely and the rest were divided into three groups of 7 animals receiving respective doses of 4, 8, and 16 microg/day of estradiol (E2) for 15 days. At the end of the study period, we determined the plasma concentrations of E2 and the concentrations of malondialdehyde (MDA) and superoxide dismutase and catalase activities in the uterus. RESULTS: There was a significant correlation (P < 0.000028) between the uterine malondialdehyde levels and the logarithm (base 10) of the plasma E2 concentrations and also between malondialdehyde and the uterine catalase activity (P < 0.002). The regression plane that best fitted the correlation among the three variables was MDA = 10.21 + 12.88 x Log [E2] - 0.49 x catalase activity. We found no significant relationships with the superoxide dismutase activity. CONCLUSIONS: There was a linear correlation between the base-10 logarithm of the estradiol plasma concentration and the phenomenon of uterine lipid peroxidation as measured by the MDA concentration in the uterus. This phenomenon was in part modulated by the inverse linear relationship between the antioxidant activity of the uterine catalase and the concentration of uterine MDA.