Determination of the lower threshold of apolipoprotein E resulting in remnant lipoprotein clearance.

Apolipoprotein E (apoE) is the ligand for receptor-mediated clearance of remnant lipoproteins. ApoE at concentrations only 10% of normal, achieved through transplantation of wild-type marrow into apoE(-/-) mice, is sufficient for the maintenance of normal serum lipid and lipoprotein levels. The goal of the present study was to identify the minimal concentration of serum apoE still affecting cholesterol levels, and to determine whether any effects on remnant clearance below this level of apoE were detectable. ApoE(+/+) marrow was mixed with apoE(-/-) marrow in proportions of 1, 5, 10, and 25% to make chimeric mice with serum levels of apoE ranging from 0.005 to 0.46 mg/dl. Analysis of serum cholesterol and apoE levels demonstrated a positive correlation between apoE levels and cholesterol reduction (r = 0.83), with levels of 0.04 mg/dl representing the functional threshold level. There were no differences in lipoprotein profiles and clearance between apoE(-/-) mice and mice with serum apoE of less than 0.04 mg/dl, as assessed by FPLC, non-denaturing gel electrophoresis, and turnover studies. However, electron microscopy of negative stains showed fewer lipoprotein particles with a diameter of <30 nm in the serum of these mice compared to apoE(-/-) mice. These data demonstrate that the threshold of serum apoE resulting in cholesterol reduction is 0. 04 mg/dl, and indicate that apoE below this level affects lipoprotein size distribution possibly by accelerating the clearance of smaller remnants.     

Meal size and feeding management strategies influence the daily rhythm of total locomotor activity in horses (Equus caballus)

Keeping and management of horses can induce changes to instinctive and innate behavioural patterns. We investigated the effect of five different management conditions in five groups of horses. All groups were housed in individual boxes under natural environmental and lighting conditions. They were fed three times a day (07:00, 12:30 and 20:00) and had free access to water. Group A was fed with 8 kg/capo/die of hay divided in the three meals. Group B was fed with 8 kg/capo/die of an unifeed divided in the three meals. Group C was fed with unifeed at 07:00 and 12:30 and with hay at 20:00. They were kept in wood-bedded boxes. Groups D and E were fed with unifeed at 07:00 and 12:30, respectively, and in the other, two meals received hay. They were kept in straw-bedded boxes. Our results showed a daily rhythm of total locomotor activity in all groups, influenced by management conditions. Group A engaged in meal patterns similar to those seen in grazing animals. Groups B and C showed the highest MESOR values due to a high searching behaviour. Group C showed a nocturnal acrophase contrary to the other groups. Groups D and E showed a total locomotor activity pattern similar to that observed in Group A probably due to an increase in straw-bedding consuming. The reduction of fibre in diet has an impact on physiology and behaviour of horses. The valuation of diet and in bedding provided to horses kept in box is useful to guarantee the maintenance of the physiological daily rhythm of total locomotor activity.     

Effect of storage time on haematological parameters in mullet,Mugil cephalus

The aim of the present study was to assess the effect of storage time at +4 °C on red blood cell count (RBC), haematocrit (Hct), haemoglobin (Hb), white blood cell count (WBC), thrombocyte count (TC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) in mullet (Mugil cephalus) using an automatic method. After blood collection (T₀), all samples were analyzed using both the manual and automatic method. To test the validation of the automatic method, a paired t‐test was applied, and no statistical difference was observed. The samples were successively divided into four different aliquots and stored at +4 °C to assess the haematological parameters using the automatic method. The first aliquot was refrigerated for 6 h, the second one for 24 h, the third one for 48 h and the last one at for 72 h. One‐way repeated‐measures ANOVA showed a significant effect of storage time (P < 0.05) on Hb, WBC, TC, MCH and MCHC. These results suggest that haematological parameters can be assessed within 6 h from blood collection when samples are stored at +4 °C because long‐term storage modifies the results of the analyses. Further studies on these parameters could be still needed in various fish species to validate an appropriate method for haematological analysis useful not only for the evaluation of the health status of animal living in captivity and in aquaculture but also to have reliability environmental haematological biomarkers. Copyright © 2012 John Wiley & Sons, Ltd.     

A new method for faster blood clearance in radioimmuno-guided surgery

A major inconvenience of intraoperative tumor detection with radiolabeled monoclonal antibody (MoAb) by means of a probe is the long interval needed between the injection of MoAb and surgery (at least 20 days). We describe a new method which entails injection of 125I-labeled biotinylated monoclonal antibodies and cold avidin in order to obtain a rapid blood clearance of the radiotracer. The first clinical application of this protocol has been carried out in a colon cancer patient operated on six days after the administration of 125I-labeled biotinylated MoAb and cold avidin, with an optimal tumor-to-normal tissue ratio and with 90% of the circulating radioactivity cleared in two days.     

Male urine signals social rank in the Mozambique tilapia (Oreochromis mossambicus)

Background  

The urine of freshwater fish species investigated so far acts as a vehicle for reproductive pheromones affecting the behaviour and physiology of the opposite sex. However, the role of urinary pheromones in intra-sexual competition has received less attention. This is particularly relevant in lek-breeding species, such as the Mozambique tilapia (Oreochromis mossambicus), where males establish dominance hierarchies and there is the possibility for chemical communication in the modulation of aggression among males. To investigate whether males use urine during aggressive interactions, we measured urination frequency of dye-injected males during paired interactions between size-matched males. Furthermore, we assessed urinary volume stored in the bladder of males in a stable social hierarchy and the olfactory potency of their urine by recording of the electro-olfactogram.     

Protein kinases in protists

Summary The vast preponderance of our understanding of protein kinases comes from studies of mammalian or of other higher eukaryotic systems. A survey of the Wilson reference databank yielded 3,807 citations for protein kinases; only nine of these were reports of protein kinases in protists. It is apparent, nonetheless, that this understudied group offers unique opportunities for resolving the mechanisms by which protein kinases mediate a variety of cellular processes. Moreover, generalities about cofactor requirements (e.g., Ca²⁺ alone activates many protist protein kinases), substrate specificity, and the nature of the enzymes themselves (monomeric versus dimeric cyclic-nucleotide dependent protein kinases) will certainly need to be modified.     

Influence of reproductive status on the daily rhythms of oxidative stress markers in <Emphasis Type="Italic">Ovis aries</Emphasis>

Changes in circadian rhythms of dROMs, Oxy-ads and SHp during reproductive stages were studied in Comisana ewes. Twelve ewes were divided in two equal groups. The experimental group consisted of ewes undergoing gestation and lactation following artificial insemination and the control group consisted of non-pregnant ewes. Blood samples were collected every 3 h over a 24 h period, 20 days before insemination, on days 100 and 140 of pregnancy, on days 10, 30 and 200 post-partum and during the dry period. In the control group, blood samples were collected on the same days and with the same procedures as those used for the experimental group. A significant effect of time on all parameters studied was observed in the experimental group. Daily rhythms of the parameters studied were observed in the control group in all experimental conditions, and in the experimental group during pre-pregnancy and dry periods. We conclude that the reproductive status of sheep affects oxidative stress markers in blood and their circadian rhythms.