Neurobiological substrates of dread

Given the choice of waiting for an adverse outcome or getting it over with quickly, many people choose the latter. Theoretical models of decision-making have assumed that this occurs because there is a cost to waiting-i.e., dread. Using functional magnetic resonance imaging, we measured the neural responses to waiting for a cutaneous electric shock. Some individuals dreaded the outcome so much that, when given a choice, they preferred to receive more voltage rather than wait. Even when no decision was required, these extreme dreaders were distinguishable from those who dreaded mildly by the rate of increase of neural activity in the posterior elements of the cortical pain matrix. This suggests that dread derives, in part, from the attention devoted to the expected physical response and not simply from fear or anxiety. Although these differences were observed during a passive waiting procedure, they correlated with individual behavior in a subsequent choice paradigm, providing evidence for a neurobiological link between the experienced disutility of dread and subsequent decisions about unpleasant outcomes.     

Influence of glycosidic linkages and molecular weight on the fermentation of maltose-based oligosaccharides by human gut bacteria

A structure-function study was carried out to increase knowledge of how glycosidic linkages and molecular weights of carbohydrates contribute toward the selectivity of fermentation by gut bacteria. Oligosaccharides with maltose as the common carbohydrate source were used. Potentially prebiotic alternansucrase and dextransucrase maltose acceptor products were synthesized and separated into different molecular weights using a Bio-gel P2 column. These fractions were characterized by matrix-assisted laser desorption/ionization time-of-flight. Nonprebiotic maltooligosaccharides with degrees of polymerization (DP) from three to seven were commercially obtained for comparison. Growth selectivity of fecal bacteria on these oligosaccharides was studied using an anaerobic in vitro fermentation method. In general, carbohydrates of DP3 showed the highest selectivity towards bifidobacteria; however, oligosaccharides with a higher molecular weight (DP6-DP7) also resulted in a selective fermentation. Oligosaccharides with DPs above seven did not promote the growth of "beneficial" bacteria. The knowledge of how specific structures modify the gut microflora could help to find new prebiotic oligosaccharides.     

Results of clinical renal transplantation in 15 dogs using triple drug immunosuppressive therapy

OBJECTIVE: To evaluate outcome of renal transplantation in dogs administered cyclosporine, azathioprine, and prednisolone immunosuppression. STUDY DESIGN: Prospective clinical study. ANIMALS: Fifteen dogs with chronic renal failure. RESULTS: Nine dogs died within 1 month of surgery; 5 died from complications associated with generalized thromboembolism. Three dogs survived for 6-25 months. Three dogs alive at the time of this report have survived 22-48 months; however, all 3 dogs have had bacterial infections that responded to antibiotic therapy. There was no biochemical evidence of acute allograft rejection in any dog. Perioperative use of enoxaparin may have prevented thromboembolism in 5 dogs. CONCLUSIONS: Triple drug immunosuppressive therapy used in this study prevented acute renal allograft rejection in 6 dogs that survived >4 weeks; however, immunosuppression was excessive, resulting in an unacceptable frequency of infection and other drug-related complications. Perioperative anticoagulation therapy seem to be warranted. CLINICAL RELEVANCE: Survival time and quality of life for this group of dogs was poor; however, there was no evidence of acute rejection in the dogs surviving >4 weeks. This protocol should only be used if the degree of immunosuppression is reduced, and early evidence of allograft rejection is monitored by renal biopsy or markers of lymphocyte activation.     

Evaluation of the effects of ischemic injury and ureteral obstruction on delayed graft function in cats after renal autotransplantation

OBJECTIVE: To determine the relative importance of ischemic injury to delayed graft function (DGF) in cats. STUDY DESIGN: Experimental study. ANIMALS: Six intact female cats. METHODS: Cats had renal autograft transplantation without ureteral transection and reimplantation and a contralateral nephrectomy. Serum creatinine and blood urea nitrogen (BUN) concentrations were measured regularly and abdominal ultrasound was performed before surgery, the day after surgery and twice weekly thereafter. Ultrasound-guided renal biopsy was performed on day 7. Cats were euthanatized on day 21. Histology of the autograft, ureter, bladder, vascular anastomoses sites, and contralateral kidney were performed. Observations were compared with those from an historic group of research cats that had extravesicular ureteroneocystostomy and contralateral nephrectomy. RESULTS: Five cats completed the study. Serum creatinine and BUN concentrations increased after surgery, peaking at 3.2+/-0.8 and 77.6+/-15.9 mg/dL, respectively, 1-2 days after surgery. Serum creatinine concentration returned to the reference interval by 6 days after surgery. BUN gradually decreased in all cats but did not return to the reference interval by study end. Serum creatinine and BUN concentrations were consistently lower but not significantly so (P=.29 and .56, respectively) compared with the historic ureteroneocystostomy group. No ultrasonographic abnormalities or renal biopsy histologic abnormalities were observed. At necropsy, 1 autograft had generalized interstitial fibrosis. CONCLUSION: Harvesting the renal graft and the ischemia before revascularization causes impaired renal function after engraftment. CLINICAL RELEVANCE: The process of harvesting and reimplanting the renal graft can contribute to DGF in cats, independent of ureteral obstruction.     

The future of training for aquatic animal health veterinarians

This article describes educational approaches for training veterinary students, veterinary graduates, and practicing veterinarians in the area of aquatic animal health and lists a range of general research, training, internship/residency, and continuing-education resources.     

Plant genotypic diversity predicts community structure and governs an ecosystem process

Theory predicts, and recent empirical studies have shown, that the diversity of plant species determines the diversity of associated herbivores and mediates ecosystem processes, such as aboveground net primary productivity (ANPP). However, an often-overlooked component of plant diversity, namely population genotypic diversity, may also have wide-ranging effects on community structure and ecosystem processes. We showed experimentally that increasing population genotypic diversity in a dominant old-field plant species, Solidago altissima, determined arthropod diversity and community structure and increased ANPP. The effects of genotypic diversity on arthropod diversity and ANPP were comparable to the effects of plant species diversity measured in other studies.     

Topography of the northern hemisphere of Mercury from MESSENGER laser altimetry

Laser altimetry by the MESSENGER spacecraft has yielded a topographic model of the northern hemisphere of Mercury. The dynamic range of elevations is considerably smaller than those of Mars or the Moon. The most prominent feature is an extensive lowland at high northern latitudes that hosts the volcanic northern plains. Within this lowland is a broad topographic rise that experienced uplift after plains emplacement. The interior of the 1500-km-diameter Caloris impact basin has been modified so that part of the basin floor now stands higher than the rim. The elevated portion of the floor of Caloris appears to be part of a quasi-linear rise that extends for approximately half the planetary circumference at mid-latitudes. Collectively, these features imply that long-wavelength changes to Mercury's topography occurred after the earliest phases of the planet's geological history.     

Innate lymphoid cells promote anatomical containment of lymphoid-resident commensal bacteria

The mammalian intestinal tract is colonized by trillions of beneficial commensal bacteria that are anatomically restricted to specific niches. However, the mechanisms that regulate anatomical containment remain unclear. Here, we show that interleukin-22 (IL-22)-producing innate lymphoid cells (ILCs) are present in intestinal tissues of healthy mammals. Depletion of ILCs resulted in peripheral dissemination of commensal bacteria and systemic inflammation, which was prevented by administration of IL-22. Disseminating bacteria were identified as Alcaligenes species originating from host lymphoid tissues. Alcaligenes was sufficient to promote systemic inflammation after ILC depletion in mice, and Alcaligenes-specific systemic immune responses were associated with Crohn's disease and progressive hepatitis C virus infection in patients. Collectively, these data indicate that ILCs regulate selective containment of lymphoid-resident bacteria to prevent systemic inflammation associated with chronic diseases.