Energy Expenditure Performing Hands-Only Cardiopulmonary Resuscitation During Average Emergency Response Times

Early cardiopulmonary resuscitation (CPR) by civilian responders is a critical aspect in the survival of cardiac arrest patients. According to the American Red Cross (ARC), the average response time to a 911 call is 8-12 min. High-quality CPR performed as soon as possible following cardiac arrest considerably increases a person’s chances of survival and recovery. It is possible that fatigue may decrease CPR quality, and to date no data exists on the metabolic cost of preforming hands-only CPR. PURPOSE: To determine the energy expenditure of performing hands-only CPR during the average emergency response time. METHODS: Eight college-aged participants (23.6 ± 4.6 years) with a current CPR certification from the ARC or American Heart Association (AHA) volunteered for the study. Anthropometric measurements were collected, participants were then fitted with a heart rate (HR) monitor. Indirect calorimetry was used to measure oxygen consumption and caloric expenditure during hands-only CPR for the minimum 8-minute response time. Participants were instructed to provide hands-only CPR to a manikin at a rate of 100-120 compressions per minute with a metronome (110 bpm) providing pacing. Descriptive statistics (mean ± SD) were evaluated for peak HR, peak metabolic equivalents (MET), estimated maximal HR, percent of maximal HR and caloric expenditure (kcals). RESULTS: Participants expended 33.3 ± 13.7 kcals when performing hands-only CPR for 8 minutes. Further, participants provided compressions at an intensity of 5.7 ± 1.5 METs. CONCLUSION: Our data suggest that the metabolic cost of performing hands-only CPR for the minimum 8-minute response time is comparable to the energy expenditure of a very brisk walk. One of the common reasons to discontinue CPR is that the responder is too exhausted to continue. The results of our study suggest it is unlikely that cardiorespiratory fatigue is the primary cause of exhaustion. Therefore, future research should aim to measure the energy expenditure of hands-only CPR to volitional exhaustion and identify perceived sources of fatigue

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

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu