Vertebrate mating strategies and life history patterns show great variation within and among species. Variation in reproductive tactics results from a combination of phylogenetic and environmental ...factors, and detailed natural and life history data among taxa are required to provide a comparative perspective or to infer evolutionary forces. Collection of such data in secretive species can often only be accomplished through long-term monitoring or the use of molecular tools. We used a combination of monitoring via radiotelemetry and microsatellite DNA markers to describe the reproductive ecology of a population of Timber Rattlesnakes, Crotalus horridus, in northwestern Arkansas. Female C. horridus in northwestern Arkansas were smaller at maturity and produce small litters compared to most estimates for other populations. Female snout–vent length and not the body condition of preparturient females was positively related to litter size and total litter mass. Both pregnant females and females found in association with males during the late-summer mating season were in better body condition compared to the general female population, suggesting an energetic component is involved in both female attractiveness and reproduction. Behavioral monitoring of radiotagged females showed that 15% of females engaging in association with a male went on to associate with additional males during that year. At least 44% of females found in association with males did not produce a litter the following year, indicating that females will associate with males (or vice versa) even with little chance of producing a litter the subsequent year. Genetic analysis of eight microsatellite markers confirmed multiple paternity in three of the seven litters analyzed. Males also associated with multiple females in a single mating season. Therefore, the mating system of C. horridus in northwestern Arkansas could probably be best described as polygynandrous.
In the 1950s and 1960s, translocation projects reintroduced black bears (Ursus americanus) from Minnesota and Manitoba to Arkansas and Louisiana. Today, several geographically disconnected ...populations exist in Arkansas and Louisiana, but their origins are unclear. Some populations may represent a separate subspecies, U. a. luteolus, which is federally protected. We characterized 5 microsatellite loci in 5 isolated populations in Arkansas and Louisiana and compared them with genotypes from Minnesota. Our data indicate that bears of the Ozark and Ouachita mountains of Arkansas, an inland area of Louisiana, and those of Minnesota are similar in overall genetic diversity and allele frequencies, consistent with these populations being wholly or mostly descended from bears from the reintroduction programs. In contrast, bears from southeastern Arkansas and the coastal region of Louisiana genetically are more restricted and homogeneous. Because they exhibit a limited set of genotypes found in the other black bear populations, they represent isolated fragments of a single North American black bear population. Furthermore, genetic distance estimates indicate that the bears in southeastern Arkansas are more genetically distinct from bears in Louisiana, which are currently federally protected.
Plexogenic arteriopathy rarely develops in existing animal models of pulmonary arterial hypertension (PAH). Rapidly growing chickens spontaneously develop PAH accompanied by the formation of ...plexiform‐like complex vascular lesions (CVL). The objective of this study was to evaluate the frequency with which at least one CVL per tissue section was observed in the lungs of chicks from lines selected for susceptibility (S) or resistance (R) to PAH. At 1, 7, 14 and 21 days of age (n ≥ 10 chicks per age and line) the CVL incidences were 33, 30, 35 and 50% for S chicks, and 20, 30, 28, and 25% for R chicks. The combined CVL incidences over days 1–21 did not differ significantly (P = 0.105) between S (36.4%) and R (25.5%) chicks. Early CVL formed when proliferating intimal cells occluded an arteriole lumen distal to branch points in muscular inter‐parabronchial arterioles that typically exhibited medial hypertrophy and intimal proliferation. Mature CVL in chicken lungs strikingly resemble published photomicrographs of plexiform lesions in the lungs of human PAH patients. The development of CVL in the lungs of young chicks suggests a complex interaction between pulmonary hemodynamics, vascular development and vascular pathology. Supported by NIH grant 1R15HL092517.
In the 1950s and 1960s, translocation projects reintroduced black bears (Ursus americanus) from Minnesota and Manitoba to Arkansas and Louisiana. Today, several geographically disconnected ...populations exist in Arkansas and Louisiana, but their origins are unclear. Some populations may represent a separate subspecies, U. a. luteolus, which is federally protected. We characterized 5 microsatellite loci in 5 isolated populations in Arkansas and Louisiana and compared them with genotypes from Minnesota. Our data indicate that bears of the Ozark and Ouachita mountains of Arkansas, an inland area of Louisiana, and those of Minnesota are similar in overall genetic diversity and allele frequencies, consistent with these populations being wholly or mostly descended from bears from the reintroduction programs. In contrast, bears from southeastern Arkansas and the coastal region of Louisiana genetically are more restricted and homogeneous. Because they exhibit a limited set of genotypes found in the other black bear populations, they represent isolated fragments of a single North American black bear population. Furthermore, genetic distance estimates indicate that the bears in southeastern Arkansas are more genetically distinct from bears in Louisiana, which are currently federally protected.
The mitochondrial regulatory region (mrr) located between the tRNAphe and tRNApro genes of mitochondrial DNA (mtDNA) is essential for regulation of replication and transcription of the mitochondrial ...genome. Polyadenylated short RNAs complementary to the L-strand of the mrr in human cells and similar RNAs (polyadenylation status unknown) in rat and mouse cells have been reported. We now report detection of ca. 0.2 kb polyadenylated mrrRNAs in cultured cells of Chinese hamster, African green monkey, mouse, rat, and human. We isolated a cDNA clone to a rat polyadenylated mrrRNA of 158 bp in length excluding the polyadenyl tail, which spans the region from the light strand promoter (LSP) to the origin of heavy strand replication (OriH). This cDNA contains both an open reading frame encoding a 26 amino acid polypeptide and a 12 nucleotide sequence complementary to the 3'-terminus of rat mitochondrial 12S rRNA. A cDNA clone to a human HeLa cell polyadenylated mrrRNA also contains a 12 nucleotide region complementary to the human mitochondrial 12S rRNA. We used a mitochondrial genome-deficient HeLa cell line, ρ° HeLa, and a derived cybrid cell line, HeEB, with a reconstituted mitochondrial genome, to demonstrate that the occurrence of the mrrRNA is dependent on the presence of a mitochondrial genome, and these polyadenylated mrrRNAs are transcribed from the mitochondrial genome. Our results further substantiate the common existence of polyadenylated mrrRNAs among mammals and support previously proposed hypotheses for the multi-functional nature of polyadenylated mrrRNA.
Whether video laryngoscopy as compared with direct laryngoscopy increases the likelihood of successful tracheal intubation on the first attempt among critically ill adults is uncertain.
In a ...multicenter, randomized trial conducted at 17 emergency departments and intensive care units (ICUs), we randomly assigned critically ill adults undergoing tracheal intubation to the video-laryngoscope group or the direct-laryngoscope group. The primary outcome was successful intubation on the first attempt. The secondary outcome was the occurrence of severe complications during intubation; severe complications were defined as severe hypoxemia, severe hypotension, new or increased vasopressor use, cardiac arrest, or death.
The trial was stopped for efficacy at the time of the single preplanned interim analysis. Among 1417 patients who were included in the final analysis (91.5% of whom underwent intubation that was performed by an emergency medicine resident or a critical care fellow), successful intubation on the first attempt occurred in 600 of the 705 patients (85.1%) in the video-laryngoscope group and in 504 of the 712 patients (70.8%) in the direct-laryngoscope group (absolute risk difference, 14.3 percentage points; 95% confidence interval CI, 9.9 to 18.7; P<0.001). A total of 151 patients (21.4%) in the video-laryngoscope group and 149 patients (20.9%) in the direct-laryngoscope group had a severe complication during intubation (absolute risk difference, 0.5 percentage points; 95% CI, -3.9 to 4.9). Safety outcomes, including esophageal intubation, injury to the teeth, and aspiration, were similar in the two groups.
Among critically ill adults undergoing tracheal intubation in an emergency department or ICU, the use of a video laryngoscope resulted in a higher incidence of successful intubation on the first attempt than the use of a direct laryngoscope. (Funded by the U.S. Department of Defense; DEVICE ClinicalTrials.gov number, NCT05239195.).
PDF
