Effects of Dinner Composition on Postprandial Macronutrient Oxidation in Prepubertal Girls

Objective: To see whether a fat‐rich (50%) evening meal promoted fat oxidation and a different spontaneous food intake on the following day at breakfast than a meal with a lower fat content (20%) in 10 prepubertal obese girls. Research Methods and Procedures: The postabsorptive and postprandial (10.5 hours) energy expenditure after a low‐fat (LF) (20% fat, 68% carbohydrate, 12% protein) and an isocaloric (2.1 MJ) and isoproteic high‐fat (HF; 50% fat, 38% carbohydrate, 12% protein) meal were measured by in direct calorimetry. Results: Fat oxidation was not significantly different after the two meals [LF, 31 ± 9 vs. HF, 35 ± 9 g/10.5 hours, p = not significant (NS)]. The girls oxidized 1.8 ± 0.9 times more fat than that ingested (11.1 grams) with the LF meal vs. 0.3 ± 0.3 times more fat than that ingested (27.1 grams) with the HF meal (p < 0.001). Carbohydrate oxidation was significantly higher after an LF than an HF meal (39 ± 12 vs. 29 ± 9 g/10.5 hours, p < 0, 05). At breakfast, the girls spontaneously ingested a similar amount of energy (1.5 ± 0.7 vs. 1.5 ± 0.6 MJ, p = NS) and macronutrient proportions (fat, 23% vs. 26%, p = NS; protein, 9% vs. 10%; carbohydrate, 68% vs. 64%,) independently of their having eaten an HF or an LF dinner. Discussion: An HF dinner did not stimulate fat oxidation, and no compensatory effect in spontaneous food intake was observed during breakfast the following morning. Cumulated total fat oxidation after dinner was higher than total fat ingested at dinner, but a much larger negative fat balance was observed after the LF meal. Spontaneous energy and nutrient intakes at breakfast were similar after LF and HF isocaloric, isoproteic dinners. This study points out the lack of sensitivity of short‐term fat balance to subsequently readjust fat intake and emphasizes the importance of an LF meal to avoid transient positive fat imbalance.     

p32 (gC1qBP) is a general protein kinase C (PKC)-binding protein; interaction and cellular localization of P32-PKC complexes in ray hepatocytes.

The aim of this study was to identify cellular proteins that bind protein kinase C (PKC) and may influence its activity and its localization. A 32-kDa PKC-binding protein was purified to homogeneity from the Triton X-100-insoluble fraction obtained from hepatocytes homogenates. The protein was identified by NH(2)-terminal amino acid sequencing as the previously described mature form of p32 (gC1qR). Recombinant p32 was expressed as a glutathione S-transferase fusion protein, affinity-purified, and tested for an in vitro interaction with PKC using an overlay assay approach. All PKC isoforms expressed in rat hepatocytes interacted in vitro with p32, but the binding dependence on PKC activators was different for each one. Whereas PKCdelta only binds to p32 in the presence of PKC activators, PKCzeta and PKCalpha increase their binding when they are in the activated form. Other PKC isoforms such as beta, epsilon, and theta bind equally well to p32 regardless of the presence of PKC activators, and PKCmu binds even better in their absence. It was also found that p32 is not a substrate for any of the PKC isoforms tested, but interestingly, its presence had a stimulatory effect (2-fold for PKCdelta) on PKC activity. We also observed in vivo interaction between PKC and p32 by immunofluorescence and confocal microscopy. A time course of phorbol ester treatment of cultured rat hepatocytes (C9 cells) showed that PKCtheta and p32 are constitutively associated in vivo, whereas PKCdelta activation is required for its association with p32. Our data also showed that phorbol ester treatment induces a transient translocation of p32 from the cytoplasm to the cell nucleus. Together, these findings suggest that p32 may be a regulator of PKC location and function.     

The effect of temperature on the behaviour and development of Triatoma brasiliensis

Abstract. The effects of temperature on the development of early stages and the thermopreference of nymphs and adults were analysed in the haematophagous bug Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae). Egg hatching, mortality of nymphs, feeding and moulting success of the early stages of T. brasiliensis were all affected by temperature. While high rates of egg hatching were observed between 25 and 27 °C, no hatching occurred at 12, 19 and 38 °C. The mortality of first‐instar nymphs was highest at 38 °C, at which no insects survived after 10 days of exposure. Feeding success was only affected at the lowest temperature (12 °C). No ecdysis was observed in the groups exposed to 12, 19 and 21 °C. Recently fed fourth‐instar nymphs preferred to stay at a temperature of approximately 30 °C. The preferred temperature began to decline gradually to approximately 27 °C during ecdysis, reaching 26 °C at 30 days after ecdysis. After a second blood meal, the insects' preferred temperature was again approximately 30 °C. The thermopreference pattern of females was similar to that of nymphs. Nymphs and females showed a daily fluctuation in their preferred temperature, moving towards higher values at the beginning of the dark phase, and choosing lower ones after this time interval, at which they remained until the end of the light phase. The females laid their eggs in all sectors of the arena, although the largest numbers of eggs were found between 28 and 32 °C.     

Genetic Variability within Borrelia burgdorferi Sensu Lato Genospecies Established by PCR-Single-Strand Conformation Polymorphism Analysis of the rrfA-rrlB Intergenic Spacer in Ixodes ricinus Ticks from the Czech Republic

In Europe the Borrelia burgdorferi sensu lato complex is represented by five distinct genospecies: Borrelia burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii, Borrelia valaisiana, and Borrelia lusitaniae. These taxonomic entities are known to differ in their specific associations with vertebrate hosts and to provoke distinct clinical manifestations in human patients. However, exceptions to these rules have often been observed, indicating that strains belonging to a single genospecies may be more heterogeneous than expected. It is, therefore, important to develop alternative identification tools which are able to distinguish Borrelia strains not only at the specific level but also at the intraspecific level. DNA from a sample of 370 Ixodes ricinus ticks collected in the Czech Republic was analyzed by PCR for the presence of a ~230-bp fragment of the rrfA-rrlB intergenic spacer of Borrelia spp. A total of 20.5% of the ticks were found to be positive. The infecting genospecies were identified by analyzing the amplified products by the restriction fragment length polymorphism (RFLP) method with restriction enzyme MseI and by single-strand conformation polymorphism (SSCP) analysis. The two methods were compared, and PCR-SSCP analysis appeared to be a valuable tool for rapid identification of spirochetes at the intraspecific level, particularly when large samples are examined. Furthermore, by using PCR-SSCP analysis we identified a previously unknown Borrelia genotype, genotype I-77, which would have gone unnoticed if RFLP analysis alone had been used.     

Home range dynamics of male roe deerCapreolus capreolus in a mountainous habitat

Male spacing behaviour of roe deer Capreolus capreolus (Linnaeus, 1758) was studied in a wooded mountainous habitat in the Casentinesi Forest National Park, Italy. Data were collected using radio-tracking techniques from March 1997 to February 1998. Annual, seasonal, and bimonthly home ranges were analysed. Different factors may influence male spacing behaviour throughout the year. Winter home range sizes may be dependent on environmental conditions, while social factors could determine a high level of individual variability during the territorial and reproductive period. Prime age males showed great spatial stability, in contrast to the ranging movements of yearlings.     

Chromosome changes in human monocytic cell lines with in vitro spontaneous malignant transformation

Summary Serial chromosome studies were performed on four monocytic cell lines established from bone marrow samples of patients suffering from hematopoietic disorders other than leukemia. A spontaneous in vitro transformation towards a malignant phenotype has been found to be related to the karyotype evolution. The correlation between the chromosome changes of these cell lines and those described in human cancer and leukemia is discussed.     

Central role of the placenta during viral infection: Immuno-competences and miRNA defensive responses

Pregnancy is a unique immunological condition in which an “immune-diplomatic” dialogue between trophoblasts and maternal immune cells is established to protect the fetus from rejection, to create a privileged environment in the uterus and to simultaneously be alert to any infectious challenge. The maternal-placental-fetal interface (MPFI) performs an essential role in this immunological defense. In this review, we will address the MPFI as an active immuno-mechanical barrier that protects against viral infections. We will describe the main viral infections affecting the placenta and trophoblasts and present their structure, mechanisms of immunocompetence and defensive responses to viral infections in pregnancy. In particular, we will analyze infection routes in the placenta and trophoblasts and the maternal-fetal outcomes in both. Finally, we will focus on the cellular targets of the antiviral microRNAs from the C19MC cluster, and their effects at both the intra- and extracellular level.     

Human plasma transforms prostacyclin (PGI2) into a platelet antiaggregatory substance which contracts isolated bovine coronary arteries

Prostacyclin (PGI₂) incubated in Human Platelet Rich Plasma (PRP); in Platelet Poor Plasma (PPP) or in Krebs-Ringer-Bicarbonate (KRB) during different periods of time on contractions of bovine coronary arteries and on the ADP platelet aggregative capacity of human PRP, were explored. It was documented that incubates in PRP or in PPP retain an antiaggregatory activity at higher levels and during a longer time than in KRB. On the other hand, PGI₂ incubates in KRB exhibited only a relaxing activity on isolated bovine coronary arteries, whereas when incubated in PRP or in PPP presented a biphasic influence. The initial effects (evoked by incubates of 30 minutes) were distinctly relaxing but those obtained with later incubates (60–150 minutes) stimulated clearly the resting basal tone of the arteries. The possibility that the human plasma might have an enzyme(s) able to transform prostacyclin into a more stable material with human antiaggregatory platelet function and bovine coronary contracting capacity is discussed.     

Interfacial Susceptibilities in Nanoplasmonics via Inversion of Fresnel Coefficients

The reflection coefficients of a nanoparticle film are driven to a large extent by perpendicular and parallel interfacial susceptibilities that have the meaning of “dielectric thicknesses” which combine the actual geometry of the film and its dielectric properties. The direct determination of these parameters faces the long-standing issue of the derivation of complex optical constants from Fresnel coefficients via a unique spectroscopic measurement. The present work sets up an iterative algorithm based on inversion of the reflection coefficients recorded in the UV–visible range for two polarization states s and p and Kramers–Kronig (KK) analysis. To calculate the KK integrals over a limited energy window, the strategy was to complement measurements by spectra calculated in the framework of the spheroidal dipole approximation. The algorithm has been successfully tested on synthetic data of differential reflectivity for supported truncated spheres. These were chosen to span different dielectric behaviors, involving (a) for the particles, metals whose optical response is dominated by plasmonic excitations with a noticeable Drude behavior (Ag and Au) and (b) for the substrate, either nonabsorbing wide bandgap (alumina) or semiconducting (zincite and titania) oxides. Unlike the thin plate model, the approach was proven to apply to “dielectric thicknesses” of several tens of nanometres in cases in which, even for geometric sizes of the order of the nanometer, the classical long-wavelength dielectric approximation fails because of strong plasmon resonances. Therefore, the disentanglement of dielectric behaviors along the parallel and perpendicular directions simplifies the understanding on the interface polarization process by removing substrate contribution. The present work that deals with plasmonics in nanoparticles can be easily generalized to different morphologies as well as to other combinations of Fresnel coefficients.