Energy Reallocation to Breeding Performance through Improved Nest Building in Laboratory Mice.

Mice are housed at temperatures (20-26°C) that increase their basal metabolic rates and impose high energy demands to maintain core temperatures. Therefore, energy must be reallocated from other biological processes to increase heat production to offset heat loss. Supplying laboratory mice with nesting material may provide sufficient insulation to reduce heat loss and improve both feed conversion and breeding performance. Naïve C57BL/6, BALB/c, and CD-1breeding pairs were provided with bedding alone, or bedding supplemented with either 8g of Enviro-Dri, 8g of Nestlets, for 6 months. Mice provided with either nesting material built more dome-like nests than controls. Nesting material improved feed efficiency per pup weaned as well as pup weaning weight. The breeding index (pups weaned/dam/week) was higher when either nesting material was provided. Thus, the sparing of energy for thermoregulation of mice given additional nesting material may have been responsible for the improved breeding and growth of offspring

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

WSES guidelines for management of Clostridium difficile infection in surgical patients

In the last two decades there have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease in many countries worldwide. The incidence of CDI has also increased in surgical patients. Optimization of management of C difficile, has therefore become increasingly urgent. An international multidisciplinary panel of experts prepared evidenced-based World Society of Emergency Surgery (WSES) guidelines for management of CDI in surgical patients.Peer reviewe

Breaking up is hard to do : does splitting cages of mice reduce aggression?

Injurious aggression in group housed male laboratory mice is a common welfare issue that can also negatively affect study outcomes. Often, one mouse in the cage appears unwounded, and the current standard practice is to remove this presumed aggressor. This procedure is not based on empirical evidence and may impede welfare by singly housing animals. We experimentally tested the hypothesis that the apparently uninjured mouse is indeed the aggressor, and that aggression is reduced in his absence. We separated cages of four or five male mice, reported for fight wounds to our university’s veterinary service, into cages of two or three mice containing either only wounded mice (“wounded” treatment) or both wounded and unwounded mice (“mixed” treatment). We recorded aggressive behavior for 30 min immediately pre- and post-separation, and scored wound severity at separation and over two weeks after. We predicted that if unwounded mice are aggressors: mice in the wounded treatment would show less escalated aggression (involving biting) than mice in the mixed treatment, and would be wounded less and/or heal faster during the two weeks following separation. Wound scores decreased significantly after separation in both treatments (wounded: p < 0.0001; mixed: p = 0.011), but mice in the wounded treatment healed faster than those in the mixed treatment (p = 0.006). There was no significant effect of treatment on duration of escalated aggression in the 30 min following separation (p = 0.240), nor did treatment predict which cages would be re-separated due to continued aggression (p = 0.104). Our results support the hypothesis that the unwounded mouse is the aggressor, as mice in cages with an unwounded mouse healed more slowly than those without. Both types of groups healed significantly over time, suggesting that separation into groups of two or three is a possible management alternative to social isolation of the presumed aggressor. By identifying spontaneous cases of severe aggression in an existing colony, we obtained a heterogeneous and representative sample of clinical cases, bolstering the generalizability of our conclusions