Venous blood lactate evaluation in equine neonatal intensive care

The use of blood lactate concentration as an indicator of prognosis and disease severity has become a common practice in equine medicine, especially with the validation of handheld analyzers. However, few authors described lactate concentration in critically ill foals, and there are no published studies about the use of handheld analyzers in neonatal foals. In this study, for the first time in the equine neonate, we validated the Lactate Scout analyzer, both in healthy and in critically ill foals. The study also describes the normal range for blood lactate in 26 healthy neonatal foals during the first 72 h of life. Moreover, the utility of venous lactate measurement in 88 critically ill foals was determined, describing lactate values in the most common neonatal pathologies, evaluating serial blood lactate measurements, and investigating its prognostic value. The comparison with the enzymatic-colorimetric reference method showed that the Lactate Scout analyzer is reliable. The mean difference (bias ±2SD) between the two methods was close to zero for all comparisons, and the SD of difference was ±0.76 with a 95% confidence interval from −1.58 to 1.40 mmol/L. In healthy foals, blood lactate concentrations at birth and at 12 h of life were statistically higher (P < 0.01) than lactate concentrations measured at subsequent times. In critically ill foals, the highest lactate concentration at admission was found in hemorrhagic shock, septic shock, and complicated perinatal asphyxia syndrome (PAS). Our results showed that hyperlactatemia, although it does not provide diagnostic information, indicates the severity of illness and the need for an early and aggressive intervention. This could be very useful both during hospitalization and in the field to support veterinarians in making a decision about referral. Furthermore lactatemia proved to be a reliable prognostic parameter: In nonsurviving foals, hyperlactatemia persisted during the entire hospitalization, whereas in survivors there were no significant differences after 24 h from admission. Because prognostic parameters have certain limitations, hyperlactatemia should not be used alone to decide whether to discontinue treatments in critically ill foals. A careful and complete clinical examination is always essential.     

Acid gel formation in (pseudo) alginates with and without G blocks produced by epimerising mannuronan with C5 epimerases

The main scope of this paper is the characterization, in terms of viscoelastic and mechanical properties, of acid gels formed from solutions of mannuronan ALG (0%G/0%GG) and its enzymatically epimerised products. The epimerised products were obtained using recombinantly produced mannuronan C5 epimerases named AlgE1 and AlgE4, which catalyse the conversion of mannuronic residues into guluronic (G) and guluronic–mannuronic (GM) blocks, respectively. The products used in this study resulted from either the action of AlgE1 on mannuronan for 5 and 24 h (named ALG(44%G/32%GG) and ALG (68%G/59%GG), respectively) or AlgE4 on mannuronan (named ALG (47%G/0%GG)). d-gluconic acid-δ-lactone (GDL) was used as H⁺-donor to produce acidic gels. ALG (0%G/0%GG) yields strong, stable solid-like structures. As predicted by circular dichroism measurements performed at different pH, gelation of ALG (47%G/0%GG) occurs at lower values of pH (1) than those obtainable using GDL. Hydrochloric acid was therefore added to ALG (47%G/0%GG) solutions yielding rapid sol–gel transitions and gels with a remarkable resistance to thermal treatment.

The introduction of guluronic residues along the chain (ALG (44%G/32%GG)) causes a reduction in the storage modulus at the equilibrium with respect to that of ALG (0%G/0%GG) and the occurrence of negligible syneresis at the highest polymer concentrations. The increase in the average length of the G blocks (ALG (68%G/59%GG)) is accompanied by a further increase in the storage modulus without the occurrence of any significant syneresis.     

Enzymatic cross-linking versus radical polymerization in the preparation of gelatin PolyHIPEs and their performance as scaffolds in the culture of hepatocytes

Highly open porous biodegradable scaffolds, based on gelatin A3, were fabricated with the aim of using them for tissue-engineering applications. The fabrication process is based on an emulsion-templating technique. In the preparation of gelatin scaffolds two different cross-linking procedures were adopted: (I) radical polymerization of the methacrylate functionalities, previously introduced onto the gelatin chains and (II) formation of isopeptide bridges among the gelatin chains promoted by the enzyme microbial transglutaminase. The method of cross-linking exerts a pronounced effect on the morphology of the porous biomaterials: radical polymerization of methacrylated gelatin allowed the production of scaffolds with a better defined porous structure, while the enzymatically cross-linked scaffolds were characterized by a thinner skeletal framework. A suitable sample of each kind of the differently cross-linked porous biomaterials was tested for the culture of hepatocytes. The scaffold obtained by radical polymerization possessed a morphology characterized by relatively large voids and interconnects, and as a consequence, it was more suitable for hepatocytes colonization. On the other hand, the enzymatically cross-linked scaffold resulted in less cytotoxicity and the cultured hepatocytes expressed a better differentiated phenotype, as evidenced by a greater expression and more correct localization of key adhesion proteins.     

C6-oxidation and c5-epimerization of locust bean galactomannan studied by high field NMR and circular dichroism

Galactose depleted locust bean gum was selectively oxidized in C(6) position and epimerized with mannuronan C(5)-epimerases to obtain the corresponding artificial uronanes. These new pseudo-alginates were characterized by NMR spectroscopy and circular dichroism (CD). Specifically, 1D and 2D NMR techniques allowed the degree of epimerization, the distribution of mannuronic and guluronic acid residues in the polysaccharidic chain, and the average G block length to be determined. In addition, NMR diffusion experiments showed that the epimerization reaction did not significantly degrade the polysaccharidic chains. Circular dichroism was used to investigate the kinetics of the epimerization reaction and to evidence the specific interaction between the epimerized locust bean samples with Ca(II) ions in dilute solution. All of the samples considered in this study form wall to wall gels in concentrated polymer solutions.     

SEC23-SEC31 the interface plays critical role for export of procollagen from the endoplasmic reticulum

COPII proteins are essential for exporting most cargo molecules from the endoplasmic reticulum. The membrane-facing surface of the COPII proteins (especially SEC23-SEC24) interacts directly or indirectly with the cargo molecules destined for exit. As we characterized the SEC23A mutations at the SEC31 binding site identified from patients with cranio-lenticulo-sutural dysplasia, we discovered that the SEC23-SEC31 interface can also influence cargo selection. Remarkably, M702V SEC23A does not compromise COPII assembly, vesicle size, and packaging of cargo molecules into COPII vesicles that we have tested but induces accumulation of procollagen in the endoplasmic reticulum when expressed in normal fibroblasts. We observed that M702V SEC23A activates SAR1B GTPase more than wild-type SEC23A when SEC13-SEC31 is present, indicating that M702V SEC23A causes premature dissociation of COPII from the membrane. Our results indicate that a longer stay of COPII proteins on the membrane is required to cargo procollagen than other molecules and suggest that the SEC23-SEC31 interface plays a critical role in capturing various cargo molecules.     

Using a dual-stable isotope tracer method to study the uptake, xylem transport and distribution of Fe and its chelating agent from stereoisomers of an Fe(III)-chelate used as fertilizer in Fe-deficient Strategy I plants

A dual-stable isotope tracer experiment was carried out with Fe-deficient sugar beet plants grown hydroponically and resupplied with differentially Fe labeled racemic and meso Fe(iii)-chelates of the ethylendiamine di(o-hydroxyphenylacetic) acid (o,oEDDHA). No short-term Fe isotope exchange reactions occurred in the nutrient solution and plants did not discriminate between (54)Fe and (57)Fe. After 3-6 h, stable Fe isotopes, chelating agents and chelates were analyzed in roots, xylem sap and leaves by ICP-MS and HPLC-ESI/TOFMS. Ferric chelate reductase rates, xylem transport and total uptake were 2-fold higher with the meso isomer than with the racemic one. Both chelating agent isomers were incorporated and distributed by plants at similar rates, in amounts one order of magnitude lower than those of Fe. After 6 h of Fe resupply, most of the Fe acquired was localized in roots, whereas most of the chelating agent was in leaves. In a separate experiment, Fe-deficient sugar beet and tomato plants were treated with different concentrations of Fe(iii)-o,oEDDHA (with a meso/racemic ratio of 1). The xylem sap Fe concentration at 24 h was unaffected by the chelate concentration, with xylem Fe(iii)-o,oEDDHA accounting for 1-18% of total Fe and xylem meso/racemic ratio close to 1. Although most of the Fe coming from Fe(iii)-o,oEDDHA was taken up through a reductive dissociative mechanism, a small part of the Fe may be taken up via non-dissociative mechanisms.     

Effects of egg testosterone on female mate choice and male sexual behavior in the pheasant

Evidence is accumulating that sex steroids in the eggs, besides affecting progeny phenotype and behavior in the short term, also have enduring effects until adulthood, when they may translate into differences in reproductive strategies and success. Maternal steroids transfer may therefore affect both agonistic behavior and mate choice decisions, either through the promotion of body size and condition or through a priming effect on the neuroendocrine system. However, owing to the prevalence of a short-term perspective, relevance of maternal transfer of sex steroids to sexual selection processes has been seldom studied. Here we investigate the effects of an experimental increase in egg testosterone on male dominance and copulation success in the ring-necked pheasant, Phasianus colchicus, a polygynous galliform with multiple male ornamental traits, in captivity. We found that females from testosterone (T) injected eggs copulated less than control females. Males from T-injected eggs obtained more copulations than control males, specifically with control females. The effect of male ‘ordinary’ and secondary sexual traits on either dominance or copulation frequency did not depend on early exposure to T, nor did T treatment affect male dominance. Present results demonstrate that variation in the early hormonal environment set up by mothers affects sexual behavior of the offspring, which might translate into fitness differences.     

Induction of alkaline phosphatase activity by exposure of human cell lines to a low-frequency electric field from apparatuses used in clinical therapies

Low‐frequency (LF) electric fields (EFs) are currently used in clinical therapies of several bone diseases to increase bone regenerative processes. To identify possible molecular mechanisms involved in these processes, we evaluated the effects on cell cultures of 1 h exposures to the signal generated by an apparatus of current clinical use (frequency 60 kHz, frequency of the modulating signal 12.5 Hz, 50% duty cycle, peak‐to‐peak voltage 24.5 V). Two different human cell lines, bone SaOS‐2 and liver HepG2, were used. Exposures significantly increased alkaline phosphatase (ALP) enzymatic activity in both cell lines. The increase was about 35% in SaOS‐2 cells and about 80% in HepG2 cells and occurred in the first 4 h after exposure and decreased to almost no change by 24 h. Since ALP represents a typical marker of bone regeneration, these results represent a first molecular evidence of biological effects from 60 kHz EF exposures. The finding of similar effects in cells derived from two different tissues more likely indicates the effective operation of the mechanism in living organisms. Bioelectromagnetics 32:113–119, 2011. © 2010 Wiley‐Liss, Inc.