Self-expanding intestinal expansion sleeves (IES) for short gut syndrome.

PURPOSE: Many disease processes (necrotizing enterocolitis, caustic esophageal injury, malrotation with volvulus), can result in short-gut syndrome (SGS), where remnant intestinal segments may dilate axially, but rarely elongate longitudinally. Here we mechanically characterize a novel model of a self-expanding mesh prototype intestinal expanding sleeve (IES) for use in SGS. METHODS: Gut lengthening was achieved using a proprietary cylindrical layered polyethylene terephthalate IES device with helicoid trusses with isometric ends. The IES is pre-contracted by diametric expansion, deployed into the gut and anchored with bioabsorbable sutures. IES expansion to its equilibrium dimension maintained longitudinal gut tension, which may permit remodeling, increased absorptive surface area while preserving vascular and nervous supplies. We performed mechanical testing to obtain the effective force-displacement characterization achieved on these prototypes and evaluated minimal numbers of sutures needed for its anchoring. Furthermore, we deployed these devices in small and large intestines of New Zealand White rabbits, measured IES length-tension relationships and measured post-implant gut expansion ex vivo. Histology of the gut before and after implantation was also evaluated. RESULTS: Longitudinal tension using IES did not result in suture failure. Maximum IES suture mechanical loading was tested using 4-6 sutures; we found similar failure loads of 2.95 ± 0.64, 4 ± 1.9 and 3.16 ± 0.24 Newtons for 4, 6 and 8 sutures, respectively (n = 3, n.s). Pre-contracted IES tubes were deployed at 67 ± 4% of initial length (i.l.); in the large bowel these expanded significantly to 81.5 ± 3.7% of i.l. (p = 0.014, n = 4). In the small bowel, pre-contracted IES were 61 ± 3.8% of i.l.; these expanded significantly to 82.7 ± 7.4% of i.l. (p = 0.0009, n = 6). This resulted in an immediate 24 ± 7.8% and 36.2 ± 11% increase in gut length when deployed in large and small bowels, respectively, with maintained longitudinal tension. Maintained IES induced tension produced gut wall thinning; gut histopathological evaluation is currently under evaluation. CONCLUSION: IES is a versatile platform for gaining length in SGS, which may be simply deployed via feeding tubes. Our results need further validation for biocompatibility and mechanical characterization to optimize use in gut expansion.

Form and Function of the Vertebrate and Invertebrate Blood-Brain Barriers.

The need to protect neural tissue from toxins or other substances is as old as neural tissue itself. Early recognition of this need has led to more than a century of investigation of the blood-brain barrier (BBB). Many aspects of this important neuroprotective barrier have now been well established, including its cellular architecture and barrier and transport functions. Unsurprisingly, most research has had a human orientation, using mammalian and other animal models to develop translational research findings. However, cell layers forming a barrier between vascular spaces and neural tissues are found broadly throughout the invertebrates as well as in all vertebrates. Unfortunately, previous scenarios for the evolution of the BBB typically adopt a classic, now discredited 'scala naturae' approach, which inaccurately describes a putative evolutionary progression of the mammalian BBB from simple invertebrates to mammals. In fact, BBB-like structures have evolved independently numerous times, complicating simplistic views of the evolution of the BBB as a linear process. Here, we review BBBs in their various forms in both invertebrates and vertebrates, with an emphasis on the function, evolution, and conditional relevance of popular animal models such as the fruit fly and the zebrafish to mammalian BBB research.

Early life stress induces dysregulation of the heme pathway in adult mice.

Early life stress (ELS) is associated with cardiovascular disease (CVD) risk in adulthood, but the underlying vascular mechanisms are poorly understood. Increased hemoglobin and heme have recently been implicated to mediate endothelial dysfunction in several vascular diseases. Chronic physiological stress is associated with alterations in the heme pathway that have been well-described in the literature. However, very little is known about the heme pathway with exposure to ELS or chronic psychosocial stress. Utilizing a mouse model of ELS, maternal separation with early weaning (MSEW), we previously reported that MSEW induces endothelial dysfunction via increased superoxide production. We reasoned that heme dysregulation may be one of the culprits induced by MSEW and sustained throughout adulthood; thus, we hypothesized that MSEW induces heme dysfunction. We investigated whether circulating levels of heme, a circulating pro-oxidant mediator, are increased by MSEW and examined the role of the heme metabolic pathway and heme homeostasis in this process. We found that circulating levels of heme are increased in mice exposed to MSEW and that plasma from MSEW mice stimulated higher superoxide production in cultured mouse aortic endothelial cells (MAECs) compared to plasma from normally reared mice. The heme scavenger hemopexin blunted this enhanced superoxide production. Splenic haptoglobin abundance was significantly lower and hemoglobin levels per red blood cell were significantly higher in MSEW versus control mice. These findings lead us to propose that ELS induces increased circulating heme through dysregulation of the haptoglobin-hemoglobin system representing a mechanistic link between ELS and CVD risk in adulthood.

3D printing of face shields to meet the immediate need for PPE in an anesthesiology department during the COVID-19 pandemic.

BACKGROUND: Anesthesia providers are at risk for contracting COVID-19 due to close patient contact, especially during shortages of personal protective equipment. We present an easy to follow and detailed protocol for producing 3D printed face shields and an effective decontamination protocol, allowing their reuse. METHODS: The University of Nebraska Medical Center (UNMC) produced face shields using a combination of 3D printing and assembly with commonly available products, and produced a simple decontamination protocol to allow their reuse. To evaluate the effectiveness of the decontamination protocol, we inoculated bacterial suspensions of E. coli and S. aureus on to the face shield components, performed the decontamination procedure, and finally swabbed and enumerated organisms onto plates that were incubated for 12-24 hours. Decontamination effectiveness was evaluated using the average log10 reduction in colony counts. RESULTS: Approximately 112 face shields were constructed and made available for use in 72 hours. These methods were successfully implemented for in-house production at UNMC and at Tripler Army Medical Center (Honolulu, Hawaii). Overall, the decontamination protocol was highly effective against both E. coli and S. aureus, achieving a ≥4 log10 (99.99%) reduction in colony counts for every replicate from each component of the face shield unit. DISCUSSION: Face shields not only act as a barrier against the soiling of N95 face masks, they also serve as more effective eye protection from respiratory droplets over standard eye shields. Implementation of decontamination protocols successfully allowed face shield and N95 mask reuse, offering a higher level of protection for anesthesiology providers at the onset of the COVID-19 pandemic. CONCLUSIONS: In a time of urgent need, our protocol enabled the rapid production of face shields by individuals with little to no 3D printing experience, and provided a simple and effective decontamination protocol allowing reuse of the face shields.

Blood-brain barrier function, cell viability, and gene expression of tight junction-associated proteins in the mouse are disrupted by crude oil, benzo[a]pyrene, and the dispersant COREXIT.

Exposure to crude oil, its components, and oil dispersants during a major crude oil spill, such as the Deepwater Horizon Oil Spill, can elicit behavioral changes in animals and humans. However, the underlying mechanisms by which oil spill-related compounds alters behavior remains largely unknown. A major cause of behavioral changes generally is dysfunction of the blood-brain barrier (BBB). We investigated the impact of a crude oil high energy water accommodated fraction (HEWAF), benzo[a] pyrene (BaP; a major component of crude oil), and the oil dispersant COREXIT, on BBB function. BBB function was assessed by measuring transendothelial electrical resistance (TEER) of mouse brain microvascular endothelial cells (BMECs). Within 3 h after treatment, TEER was significantly reduced by exposure to high concentrations of all test compounds. TEER remained reduced in response to COREXIT after 48 h, but this effect waned in BMECs treated with HEWAF and BaP, with low-mid range concentrations inducing increased TEER compared to vehicle controls. At 48 h of treatment, BMEC viability was significantly reduced in response to 2% HEWAF, but was increased in response to BaP (25 and 50 µM). BMEC viability was increased with 80 ppm COREXIT, but was reduced with 160 ppm. Gene expression of tight junction-associated proteins (claudin-5 and tight junction protein-1), and cell adhesion receptor (vascular cell adhesion molecule-1) was reduced in response to HEWAF and COREXIT, but not BaP. Taken together, these data suggest that oil spill-related compounds markedly affect BBB function, and that these changes may underlie the observed behavioral changes due to crude oil exposure.

Polyomaviruses of the skin: integrating molecular and clinical advances in an emerging class of viruses.

BACKGROUND: Human polyomaviruses (HPyVs) are small, nonenveloped, double-stranded DNA viruses that express tumour antigen proteins. Fourteen species of polyomaviruses have been discovered in humans, and since the 2008 discovery of the first cutaneous polyomavirus - Merkel cell polyomavirus (MCPyV) - six more species have been detected in the skin: trichodysplasia spinulosa-associated polyomavirus (TSPyV), HPyV6, HPyV7, HPyV9, HPyV10 and HPyV13. Of these cutaneous species, only MCPyV, TSPyV, HPyV6 and HPyV7 have been definitively associated with diseases of the skin, most commonly in immunocompromised individuals. MCPyV is a predominant aetiology in Merkel cell carcinomas. TSPyV is one of the aetiological factors of trichodysplasia spinulosa. HPyV6 and HPyV7 have been recently linked to pruritic skin eruptions. The roles of HPyV9, HPyV10 and HPyV13 in pathogenesis, if any, are still unknown, but their molecular features have provided some insight into their functional biology. RESULTS: In this review, we summarize the known molecular mechanisms, clinical presentation and targeted therapies of each of the eight cutaneous HPyVs. CONCLUSIONS: We hope that heightened awareness and clinical recognition of HPyVs will lead to increased reports of HPyV-associated diseases and, consequently, a more robust understanding of how to diagnose and treat these conditions.

Chronic Pruritus: A Review of Neurophysiology and Associated Immune Neuromodulatory Treatments.

Chronic pruritus remains a difficult condition to treat with many non-specific therapeutic options. Recent scientific discoveries have elucidated the physiology associated with pruritus. Combined with clinical and experimental trials with immune-modulatory agents, chronic pruritus now has novel treatment options with known mechanisms of action. This review goes over recent scientific progress in understanding the molecular mechanisms governing pruritus, the cross-talk between the immune and nervous systems that regulate itch, and central nervous pathways and projections affected by itch. In light of these recent discoveries, we briefly discuss a growing body of data from relevant clinical trials investigating immunomodulatory drugs targeting specific interleukin receptors (IL-4/13/31) and intracellular signaling (e.g., Janus kinase) pathways. We focus on the physiological processes that control this complex physical and emotional experience, as well as the role of newer drugs used to treat chronic itch.

Early life stress induces immune priming in kidneys of adult male rats.

Early life stress (ELS) in humans is associated with elevated proinflammatory markers. We hypothesized that ELS induces activation of the immune response in a rat model of ELS, maternal separation (MatSep), in adulthood. MatSep involves separating pups from the dam from postnatal day 2 to postnatal day 14 for 3 h/day. Control rats are nonseparated littermates. We determined circulating and renal immune cell numbers, renal immune cell activation markers, renal cytokine levels, and the renal inflammatory gene expression response to low-dose lipopolysaccharide (LPS) in male MatSep and control rats. We observed that MatSep did not change the percentage of gated events for circulating CD3+, CD4+, CD8+, and CD4+/Foxp3+ cells or absolute numbers of mononuclear and T cells in the circulation and kidneys; however, MatSep led to an increase in activation of renal neutrophils as well as CD44+ cells. Renal toll-like receptor 4 (TLR4) and interleukin 1 beta (IL-1ß) was significantly increased in MatSep rats, specifically in the outer and inner medulla and distal nephron, respectively. Evaluation of renal inflammatory genes showed that in response to a low-dose LPS challenge (2 mg/kg iv) a total of 20 genes were significantly altered in kidneys from MatSep rats (17 genes were upregulated and 3 were downregulated), as opposed to no significant differences in gene expression in control vs. control + LPS groups. Taken together, these findings indicate that MatSep induces priming of the immune response in the kidney.

Metabolic rate and hypoxia tolerance are affected by group interactions and sex in the fruit fly (Drosophila melanogaster): new data and a literature survey.

Population density and associated behavioral adjustments are potentially important in regulating physiological performance in many animals. In r-selected species like the fruit fly (Drosophila), where population density rapidly shifts in unpredictable and unstable environments, density-dependent physiological adjustments may aid survival of individuals living in a social environment. Yet, how population density (and associated social behaviors) affects physiological functions like metabolism is poorly understood in insects. Additionally, insects often show marked sexual dimorphism (larger females). Thus, in this study on D. melanogaster, we characterized the effects of fly density and sex on both mass-specific routine oxygen consumption (V̇O2) and hypoxia tolerance (PCrit). Females had significantly lower routine V̇O2 (∼4 µl O2 mg-1 h-1) than males (∼6 µl O2 mg-1 h-1) at an average fly density of 28 flies·respirometer chamber-1 However, V̇O2 was inversely related to fly density in males, with V̇O2 ranging from 4 to 11 µl O2 mg-1 h-1 at a density of 10 and 40 flies·chamber-1, respectively (r2=0.58, P<0.001). Female flies showed a similar but less pronounced effect, with a V̇O2 of 4 and 7 µl O2 mg-1 h-1 at a density of 10 and 40 flies·chamber-1, respectively (r2=0.43, P<0.001). PCrit (∼5.5 to 7.5 kPa) varied significantly with density in male (r2=0.50, P<0.01) but not female (r2=0.02, P>0.5) flies, with higher fly densities having a lower PCrit An extensive survey of the literature on metabolism in fruit flies indicates that not all studies control for, or even report on, fly density and gender, both of which may affect metabolic measurements.

Novel genomic microsatellite markers for genetic population and diversity studies of tropical scalloped spiny lobster (Panulirus homarus) and their potential application in related Panulirus species.

Fourteen polymorphic microsatellites with perfect di-, tri-, and tetra-nucleotide repeats were identified for Panulirus homarus using Roche 454 whole-genome sequencing method. Microsatellites were efficiently co-amplified in four multiplexes and a singleplex, providing consistent and easily interpretable genotypes. The number of alleles per locus ranged from 2 to 11 with the observed and expected heterozygosity ranging between 0.000-0.532 and 0.031-0.836, respectively. A significant deviation from Hardy-Weinberg equilibrium was observed for majority of the loci, probably due to homozygote excess. Genetic linkage disequilibrium analysis between all the possible pairs of the loci showed significant departure from the null hypothesis in the loci pairs Pho-G11-Pho-G33 and Pho-G33-Pho-G57. High success in primer cross-species amplification of these microsatellite markers indicates their utility for genetic studies of different Panulirus species.

Early life stress in male mice induces superoxide production and endothelial dysfunction in adulthood.

Early life stress (ELS) is a risk for cardiovascular disease in adulthood although very little mechanistic insight is available. Because oxidative stress and endothelial dysfunction are major contributors to cardiovascular risk, we hypothesized that ELS induces endothelial dysfunction in adult male mice via increased superoxide production. Studies employed a mouse model of ELS, maternal separation with early weaning (MSEW), in which litters were separated from the dam for 4 h/day [postnatal days (PD) 2-5] and 8 h/day (PD6-16), and weaned at PD17. Control litters remained undisturbed until weaning at PD21. When compared with control mice, thoracic aortic rings from adult male MSEW mice displayed significant endothelial dysfunction that was reversed by the superoxide scavenger, polyethylene glycol-superoxide dismutase (PEG-SOD). PEG-SOD-inhibitable superoxide production by aortae from MSEW mice was significantly greater than observed in control aortae, although unaffected by nitric oxide synthase inhibition, suggesting that uncoupled nitric oxide synthase was not responsible for the accelerated superoxide production. Aortic SOD expression, plasma SOD activity, and total antioxidant activity were similar in MSEW and control mice, indicating unaltered antioxidant capacity in MSEW mice. Increased expression of the NADPH oxidase subunits, NOX2 and NOX4, was evident in the aortae of MSEW mice. Moreover, endothelial dysfunction and superoxide production in MSEW mice was reversed with the NADPH oxidase inhibitor, apocynin, indicating increased NADPH oxidase-dependent superoxide production and endothelial dysfunction. The finding that MSEW induces superoxide production and endothelial dysfunction in adult mice may provide a mechanistic link between ELS and adult cardiovascular disease risk.

Dahl SS rats demonstrate enhanced aortic perivascular adipose tissue-mediated buffering of vasoconstriction through activation of NOS in the endothelium.

Perivascular adipose tissue (PVAT) mediates buffering of vasoconstriction through activation of endothelium-derived factors. We hypothesized that the PVAT of Dahl salt-sensitive (Dahl SS) rats has reduced ability to buffer vasoconstriction. Vascular reactivity experiments were performed on aortic rings with PVAT intact (+PVAT) or removed (-PVAT), and endothelium intact (+ENDO) or removed (-ENDO) from Dahl SS rats and control SS.13(BN) rats (Dahl SS rats that have had chromosome 13 completely replaced with that of the Brown Norway rat, rendering this strain insensitive to high-salt or high-fat diet-induced hypertension). Endothelial dysfunction, assessed by ACh-mediated vasorelaxation, was confirmed in aortic rings of Dahl SS rats. The +PVAT+ENDO aortic rings had indistinguishable phenylephrine-induced vasoconstriction between genotypes. In both strains, removal of PVAT significantly enhanced vasoconstriction. Dahl SS rat -PVAT+ENDO aortic rings displayed exaggerated vasoconstriction to phenylephrine vs. SS.13(BN) rats, indicating that PVAT-mediated buffering of vasoconstriction was greater in Dahl SS rats. Removal of both the ENDO and PVAT restored vasoconstriction in both strains. The nitric oxide synthase (NOS) inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), produced a similar effect as that seen with -ENDO. These data indicate that the function of the PVAT to activate endothelium-derived NOS is enhanced in Dahl SS compared with SS.13(BN) rats and, most likely, occurs through a pathway that is distinct from ACh-mediated activation of NOS. PVAT weight and total PVAT leptin levels were greater in Dahl SS rats. Leptin induced a significantly decreased vasoconstriction in -PVAT+ENDO aortic rings from Dahl SS rats, but not SS.13(BN) rats. In contrast to our initial hypothesis, PVAT in Dahl SS rats buffers vasoconstriction by activating endothelial NOS via mechanisms that may include the involvement of leptin. Thus, the PVAT serves a vasoprotective role in Dahl SS rats on normal-salt diet.

The Lissajous lens: a three-dimensional absolute optical instrument without spherical symmetry.

We propose a three dimensional optical instrument with an isotropic gradient index in which all ray trajectories form Lissajous curves. The lens represents the first absolute optical instrument discovered to exist without spherical symmetry (other than trivial cases such as the plane mirror or conformal maps of spherically-symmetric lenses). An important property of this lens is that a three-dimensional region of space can be imaged stigmatically with no aberrations, with a point and its image not necessarily lying on a straight line with the lens center as in all other absolute optical instruments. In addition, rays in the Lissajous lens are not confined to planes. The lens can optionally be designed such that no rays except those along coordinate axes form closed trajectories, and conformal maps of the Lissajous lens form a rich new class of optical instruments.

Isolation, characterization, and multiplexing of novel microsatellite markers for the tropical scalloped spiny lobster (Panulirus homarus).

Of the various spiny lobster species in the tropical and subtropical Indo-West Pacific region, the tropical scalloped spiny lobster (Panulirus homarus) supports one of the most commercially valuable fishery resources in many coastal African and Asian countries. The last decade has witnessed a serious decline in the wild populations of this species. Knowledge of the genetic basis of spiny lobster population structure is a prerequisite to achieve a sustainable fisheries management for this species. Here, we describe 13 novel polymorphic microsatellite markers developed for P. homarus, using a cross-species primer design strategy based on P. ornatus Roche 454 shot-gun generated sequencing. Microsatellite polymorphisms were assessed in 96 unrelated P. homarus individuals of a natural population, with the number of alleles per locus varying from 2 to 14, the observed and expected heterozygosity from 0.00 to 0.78 and from 0.03 to 0.79, respectively, and with only four loci (Pho-G27, Pho-G32, Pho-G36, and Pho-G58) deviating from Hardy- Weinberg equilibrium. Genetic linkage disequilibrium analysis between all pairs of the loci showed significant departure from the null hypothesis between loci Pho-G22 - Pho-G30, and Pho-G30 - Pho-G35. The successful cross amplification of these microsatellites highlights the potential of the developed microsatellites for future population genetic research within the different Panulirus species.

Histone deacetylase 1 reduces NO production in endothelial cells via lysine deacetylation of NO synthase 3.

The lysine acetylation state of nonhistone proteins may be regulated through histone deacetylases (HDACs). Evidence suggests that nitric oxide (NO) synthase 3 (NOS3; endothelial NOS) is posttranslationally lysine acetylated, leading to increased NO production in the endothelium. We tested the hypothesis that NOS3 is lysine acetylated and that upregulated HDAC1-mediated deacetylation leads to reduced NO production in endothelial cells. We determined that NOS3 is basally lysine acetylated in cultured bovine aortic endothelial cells (BAECs). In BAECs, HDAC1 is expressed in the nucleus and cytosol and forms a novel protein-protein interaction with NOS3. Overexpression of HDAC1 in BAECs resulted in a significant reduction in NOS3 lysine acetylation (control = 1.0 ± 0.1 and HDAC1 = 0.59 ± 0.08 arbitrary units, P < 0.01) and significantly blunted basal nitrite production (control 287.7 ± 29.1 and HDAC1 172.4 ± 31.7 pmol·mg(-1)·h(-1), P < 0.05) as well as attenuating endothelin-1-stimulated nitrite production (control = 481.8 ± 50.3 and HDAC1 243.1 ± 48.2 pmol·mg(-1)·h(-1), P < 0.05). While HDAC1 knockdown with small-interfering RNA resulted in no change in NOS3 acetylation level, yet increased basal nitrite production (730.6 ± 99.1 pmol·mg(-1)·h(-1)) and further exaggerated increases in endothelin-1 stimulated nitrite production (1276.9 ± 288.2 pmol·mg(-1)·h(-1)) was observed. Moreover, overexpression or knockdown of HDAC1 resulted in no significant effect on NOS3 protein expression or NOS3 phosphorylation sites T497, S635, or S1179. Thus these data indicate that upregulated HDAC1 decreases NOS3 activity, most likely through direct lysine deacetylation of NOS3. We propose that HDAC1-mediated deacetylation of NOS3 may represent a novel target for endothelial dysfunction.

Transgenerational epigenetics: the role of maternal effects in cardiovascular development.

Transgenerational epigenetics, the study of non-genetic transfer of information from one generation to the next, has gained much attention in the past few decades due to the fact that, in many instances, epigenetic processes outweigh direct genetic processes in the manifestation of aberrant phenotypes across several generations. Maternal effects, or the influences of maternal environment, phenotype, and/or genotype on offsprings' phenotypes, independently of the offsprings' genotypes, are a subcategory of transgenerational epigenetics. Due to the intimate role of the mother during early development in animals, there is much interest in investigating the means by which maternal effects can shape the individual. Maternal effects are responsible for cellular organization, determination of the body axis, initiation and maturation of organ systems, and physiological performance of a wide variety of species and biological systems. The cardiovascular system is the first to become functional and can significantly influence the development of other organ systems. Thus, it is important to elucidate the role of maternal effects in cardiovascular development, and to understand its impact on adult cardiovascular health. Topics to be addressed include: (1) how and when do maternal effects change the developmental trajectory of the cardiovascular system to permanently alter the adult's cardiovascular phenotype, (2) what molecular mechanisms have been associated with maternally induced cardiovascular phenotypes, and (3) what are the evolutionary implications of maternally mediated changes in cardiovascular phenotype?

Ant-coccid mutualism in citrus canopies and its effect on natural enemies of red scale, Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae).

Mutualistic relationships between honeydew-producing insects and ants have been widely recognized for several decades. Iridomyrmex rufoniger (Lowne) is the commonest ant species associated with black scale, Saissetia oleae (Olivier), in the citrus orchards of the mid latitudes of coastal New South Wales. Citrus trees with high densities of both red and black scale and high ant activity were identified and the results of excluding ants from half of those trees (using a polybutene band on each trunk) were compared with the results of not excluding ants from the other half. Trees with a low incidence of black scale and ants were also studied. Exclusion of ants from trees was soon followed by collapse of black scale populations because most individuals were asphyxiated by their own honeydew. Also, parasitism of the red scale by Encarsia perniciosi (Tower) and Encarsia citrina Craw was significantly higher than in the control trees over the following year, as was the predation rate on red scale due to three coccinellid predators, Halmus chalybeus (Boisduval), Rhyzobius hirtellus Crotch and Rhyzobius lophanthae (Blaisdell). In contrast, another coccinellid, Orcus australasiae (Boisduval), and a noctuid moth larva, Mataeomera dubia Butler, were seen in low numbers on banded (ant exclusion) trees, probably because of the low availability of their black scale prey, but were significantly higher on control trees apparently because of their invulnerability to ants.

Parental hypoxic exposure confers offspring hypoxia resistance in zebrafish (Danio rerio).

Parental influences are a potentially important component of transgenerational transfer of phenotype in vertebrates. This study examined how chronic hypoxic exposure on adult zebrafish (Danio rerio) affected the phenotype of their offspring. Separate adult populations were exposed to hypoxia (13.1 kPa O(2)) or normoxia (21.1 kPa O(2)) for periods ranging from 1 to 12 weeks. Adults were then returned to normoxia and bred within experimental groups. Adult fecundity and egg characteristics (volume of egg, yolk and perivitelline fluid) were assessed. Subsequently, larval body length, time to loss of equilibrium in severe hypoxia (~4 kPa O(2)), and critical thermal minima (CT(min)) and maxima (CT(max)) were measured at 6, 9, 12, 15, 18, 21 and 60 days post-fertilization (d.p.f.). Adult fecundity was depressed by hypoxic exposure. Egg component volumes were also depressed in adults exposed to 1-2 weeks of hypoxia, but returned to control levels following longer hypoxic exposure. Adult hypoxic exposures of >1 week resulted in longer body lengths in their larval offspring. Time to loss of equilibrium in severe hypoxia (i.e. hypoxic resistance) in control larvae decreased from 6 to 12 d.p.f., remaining constant thereafter. Notably, hypoxic resistance from 6 to 18 d.p.f. was ~15% lower in larvae whose parents were exposed to just 1 week of chronic hypoxia, but resistance was significantly increased by ~24-30% in 6-18 d.p.f. larvae from adults exposed to 2, 3 or 4 weeks of hypoxia. CT(min) (~10-12°C) and CT(max) (~39.5°C) were unchanged by parental hypoxic exposure. This study demonstrates that parental hypoxic exposure in adult zebrafish has profound epigenetic effects on the morphological and physiological phenotype of their offspring.

Changing standard chow diet promotes vascular NOS dysfunction in Dahl S rats.

We hypothesized that vascular nitric oxide synthase (NOS) function and expression is differentially regulated in adult Dahl salt-sensitive rats maintained on Teklad or American Institutes of Nutrition (AIN)-76A standard chow diets from 3 to 16 wk old. At 16 wk old, acetylcholine (ACh)-mediated vasorelaxation and phenylephrine (PE)-mediated vasoconstriction in the presence and absence of NOS inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), was assessed in small-resistance mesenteric arteries and aortas. Rats maintained on either diet throughout the study had similar responses to ACh and PE in the presence or absence of L-NAME in both vascular preparations. We reasoned that changing from one diet to another as adults may induce vascular NOS dysfunction. In the absence of L-NAME, small arteries from Teklad-fed rats switched to AIN-76 diet and vice versa had similar responses to ACh and PE. Small-arterial NOS function was maintained in rats switched to AIN-76A from Teklad diet, whereas NOS function in response to ACh and PE was lost in the small arteries from rats changed to Teklad from AIN-76A diet. This loss of NOS function was echoed by reduced expression of NOS3, as well as phosphorylated NOS3. The change in NOS phenotype in the small arteries was observed without changes in blood pressure. Aortic responses to ACh or PE in the presence or absence of L-NAME were similar in all diet groups. These data indicate that changing standard chow diets leads to small arterial NOS dysfunction and reduced NOS signaling, predisposing Dahl salt-sensitive rats to vascular disease.