Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus)

The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations.     

Household obesity prevention: Take Action--a group-randomized trial

The purpose of the present study was to evaluate an intervention to prevent weight gain among households (HHs) in the community. Ninety HHs were randomized to intervention or control group for 1 year. Intervention consisted of six face-to-face group sessions, placement of a television (TV) locking device on all home TVs, and home-based intervention activities. Measures were collected in person at baseline and 1 year. Weight, height, eating behaviors, physical activity (PA), and TV viewing were measured among HH members ages ≥ 12 years. Follow-up rate at 1 year was 96%. No significant intervention effects were observed for change in HH BMI-z score. Intervention HHs significantly reduced TV viewing, snacks/sweets intake, and dollars per person spent eating out, and increased (adults only) PA and self-weighing frequency compared with control HHs. A 1 year obesity prevention intervention targeting entire HHs was effective in reducing TV viewing, snack/sweets intake and eating out purchases. Innovative methods are needed to strengthen the home food environment intervention component. Longer intervention durations also need to be evaluated.     

A dye mixture (Neurobiotin and Alexa 488) reveals extensive dye-coupling among neurons in leeches; physiology confirms the connections

Although the neuronal circuits that generate leech movements have been studied for over 30 years, the list of interneurons (INs) in these circuits remains incomplete. Previous studies showed that some motor neurons (MNs) are electrically coupled to swim-related INs, e.g., rectifying junctions connect IN 28 to MN DI-1 (dorsal inhibitor), so we searched for additional neurons in these behavioral circuits by co-injecting Neurobiotin and Alexa Fluor 488 into segmental MNs DI–1, VI–2, DE–3 and VE–4. The high molecular weight Alexa dye is confined to the injected cell, whereas the smaller Neurobiotin molecules diffuse through gap junctions to reveal electrical coupling. We found that MNs were each dye-coupled to approximately 25 neurons, about half of which are likely to be INs. We also found that (1) dye-coupling was reliably correlated with physiologically confirmed electrical connections, (2) dye-coupling is unidirectional between MNs that are linked by rectifying connections, and (3) there are novel electrical connections between excitatory and inhibitory MNs, e.g. between excitatory MN VE-4 and inhibitory MN DI-1. The INs found in this study provide a pool of novel candidate neurons for future studies of behavioral circuits, including those underlying swimming, crawling, shortening, and bending movements.     

Measurement of myocardial mechanics in mice before and after infarction using multislice displacement-encoded MRI with 3D motion encoding

Cardiac MRI is an accurate, noninvasive modality for assessing the structure and function of the murine heart. In addition to conventional imaging, MRI tissue tracking methods can quantify numerous aspects of myocardial mechanics, including intramyocardial displacement, strain, twist, and torsion. In the present study, we developed and applied a novel pulse sequence based on displacement-encoded imaging using stimulated echoes (DENSE) that achieves multislice coverage, high spatial resolution, and three-dimensional (3D) displacement encoding. With the use of this technique, myocardial mechanics of C57Bl/6 mice were measured at baseline and 1 day after experimental myocardial infarction. At baseline, the mean systolic transmural circumferential strain was -0.14 +/- 0.02 and the mean systolic radial strain was 0.30 +/- 0.05. Changes in circumferential and radial strains from the subepicardium to the subendocardium were detected at baseline (P < 0.05). One day after infarction, significantly reduced 3D displacements and strain were detected in infarcted and noninfarcted myocardium. Infarction also reduced normalized systolic torsion from its baseline value of 1.35 +/- 0.27 degrees /mm (R = 0.99) to 0.07 +/- 0.54 degrees /mm (R = 0.96, P < 0.05). DENSE MRI can assess the 3D myocardial mechanics of the murine heart in <1 h of scan time at 4.7 T and may be applied to studies of myocardial mechanics in genetically engineered mice.     

The E2 glycoprotein of classical swine fever virus is a virulence determinant in swine

To identify genetic determinants of classical swine fever virus (CSFV) virulence and host range, chimeras of the highly pathogenic Brescia strain and the attenuated vaccine strain CS were constructed and evaluated for viral virulence in swine. Upon initial screening, only chimeras 138.8v and 337.14v, the only chimeras containing the E2 glycoprotein of CS, were attenuated in swine despite exhibiting unaltered growth characteristics in primary porcine macrophage cell cultures. Additional viral chimeras were constructed to confirm the role of E2 in virulence. Chimeric virus 319.1v, which contained only the CS E2 glycoprotein in the Brescia background, was markedly attenuated in pigs, exhibiting significantly decreased virus replication in tonsils, a transient viremia, limited generalization of infection, and decreased virus shedding. Chimeras encoding all Brescia structural proteins in a CS genetic background remained attenuated, indicating that additional mutations outside the structural region are important for CS vaccine virus attenuation. These results demonstrate that CS E2 alone is sufficient for attenuating Brescia, indicating a significant role for the CSFV E2 glycoprotein in swine virulence.     

Modifications in P62 occur due to proteasome inhibition in alcoholic liver disease

P62 is capable of binding the polyubiquitin chain that targets proteins for degradation by the proteasome through its ubiquitin associated domain (UBA). Immunostaining of hepatocytes from human liver with alcoholic hepatitis showed colocalization of ubiquitin and P62 in Mallory bodies. Rats fed ethanol chronically and their controls showed that P62 is colocalized with the proteasome in hepatocytes as shown by confocal microscopy. P62 cosedimented with 26S proteasomes isolated from livers of control and alcohol fed rats. P62 was increased in the 26S proteasome fraction when the proteasome chymotrypsin-like (ChT-L) activity decreased in rats fed ethanol. PS-341, a potent proteasome inhibitor was used to compare the inhibition of the proteasome with the inhibition which occurs with ethanol feeding. P62 protein levels were also increased in the purified proteasome fraction of rats given PS-341. This data indicates that modifications in P62 occur due to proteasome inhibition in experimental alcoholic liver disease.     

A nanoparticle-based model delivery system to guide the rational design of gene delivery to the liver. 2. In vitro and in vivo uptake results

In Part 1 of our work (1), four nanoparticles were synthesized specifically for the purpose of identifying design constraints to guide next generation gene delivery to the liver. The four nanoparticles are Gal-50 and Gal-140 (galactosylated 50 and 140 nm nanoparticles) and MeO-50 and MeO-140 (methoxy-terminated 50 and 140 nm nanoparticles). All four particles have the same surface charge, and Gal-50 and Gal-140 have the same surface galactose density (ca. 25-30 pmol/cm2). Here, the hepatocyte uptake in vitro and hepatic distribution in vivo of these four nanoparticles is investigated. With freshly isolated hepatocytes, Gal-50 nanoparticles are taken up to a greater extent than are MeO-50, and both 50 nm beads are taken up to a much greater extent than either of the 140 nm nanoparticles. In mice, about 90% of the in vivo dose of Gal-140 nanoparticles is found within the liver 20 min after tail-vein injection. TEM and immunohistochemistry images confirm that Gal-140 nanoparticles are primarily internalized by Kupffer cells, though isolated examples of a few Gal-140 in hepatocytes are also observed. Gal-50 nanoparticles are overwhelmingly found in vesicles throughout the cytoplasm of hepatocytes, with only isolated examples of Kupffer cell uptake 20 min after tail vein injections in mice. Despite similar surface charge and ligand density, 50 nm nanoparticles are primarily found in hepatocytes while 140 nm nanoparticles are primarily observed in Kupffer cells. These results clearly show that slightly anionic, galactose-PEGylated nanoparticles with 25-30 pmol/cm2 galactose should be about 50 nm in diameter to preferentially target hepatocytes while they should be about 140 nm in diameter to selectively target Kupffer cells.     

Effects of treatment with a cetylated fatty acid topical cream on static postural stability and plantar pressure distribution in patients with knee osteoarthritis

The purpose of the present investigation was to examine the effects of 30 days of treatment with a topical cream consisting of cetylated fatty acids on static postural stability and plantar pressures in patients with osteoarthritis (OA) of one or both knees. Forty patients diagnosed with knee OA were randomly assigned to 1 of 2 topical treatment groups: (a) cetylated fatty acid (CFA; N = 20; age = 62.7 +/- 11.7 years); or (b) placebo (P; N = 20; age = 64.6 +/- 10.5 years). Patients were tested on 2 occasions: (a) baseline (T1), and (b) following a 30-day treatment period consisting of cream application twice per day (T2). Assessments included 20- and 40-second quiet standing protocols on a force plate to measure center of pressure (COP) total excursion length, COP velocity, and rearfoot and forefoot plantar pressure distribution. In the CFA group, a significant reduction in the COP excursion length and velocity were observed at T2, whereas no significant differences were observed in the P group. No significant differences in mean forefoot, rearfoot, or rearfoot-to-forefoot plantar pressure ratios were observed in either group at T2. However, in a subgroup of participants designated to be right- or left-side dominant, improvements in the right-to-left forefoot plantar pressure ratios were observed in both groups. These data indicate that 30 days of treatment with a topical cream consisting of cetylated fatty acids improves static postural stability in patients with knee OA presumably due to pain relief during quiet standing. Such over-the-counter treatment may help improve the exercise trainability of people with OA.     

Androgen receptor content following heavy resistance exercise in men

The purpose of the present investigation was to examine androgen receptor (AR) content in the vastus lateralis following two resistance exercise protocols of different volume. Nine resistance-trained men (age=24.3+/-4.4 years) performed the squat exercise for 1 (SS) and 6 sets (MS) of 10 repetitions in a random, counter-balanced order. Muscle biopsies were performed at baseline, and 1h following each protocol. Blood was collected prior to, immediately following (IP), and every 15 min after each protocol for 1h. No acute elevations in serum total testosterone were observed following SS, whereas significant 16-23% elevations were observed at IP, 15, and 30 min post-exercise following MS. No acute elevations in plasma cortisol were observed following SS, whereas significant 31-49% elevations were observed for MS at IP, 15, and 30 min post-exercise. Androgen receptor content did not change 1h following SS but significantly decreased by 46% following MS. These results demonstrated that a higher volume of resistance exercise resulted in down-regulation of AR content 1h post-exercise. This may have been due to greater protein catabolism associated with the higher level of stress following higher-volume resistance exercise.