During 2003 and 2004, carabid beetles were collected from the 9 largest spruce-fir sites located in the southern Appalachian Mountains. Thirty-seven species were identified from 1817 individuals of ...Carabidae caught in these habitats. When adjusted for sample size, carabid beetle diversity was highest at Grandfather Mt., NC and lowest at Mt. Rogers, VA. Results from non-metric multi-dimensional scaling (NMS) ordination analysis indicate that carabid species found in spruce-fir forest cluster independently from those found in deciduous lower-elevation forests. There were no correlations between carabid species diversity and habitat area, isolation, and elevation.
We investigated heterotopic hepatocyte transplantation on biodegradable polymers as a potential treatment for end-stage liver disease. The primary problem has been insufficient engraftment of ...transplanted cells partly because of insufficient vascularization. Increasing vascularization through locally delivered angiogenic factors may increase angiogenesis and hepatocyte engraftment.
We studied the effect of local delivery of basic fibroblast growth factor (bFGF) on angiogenesis and hepatocyte engraftment within tissue-engineered liver constructs. Poly-l-lactic acid discs were fabricated and coated with either a mixture of saline, sucralfate, and Hydron (control group) or bFGF, sucralfate, and Hydron (bFGF group). bFGF release from polymers in vitro was tested using an ELISA. Hepatocytes were isolated from Lewis rats, seeded on control (n=9) or bFGF (n=11) polymers, and implanted into the small bowel mesentery of syngeneic animals. Specimens were harvested after 2 weeks and analyzed for hepatocyte engraftment. Microvascular density was compared between control (n=6) and bFGF groups (n=5).
Three hundred twenty-three thousandths of a microgram of bFGF were incorporated per polymer. Greater than 99% of the bFGF was released into solution by 72 hr in vitro. Two weeks after implantation, microvascular density, as measured by capillaries per high-powered field (c/hpf), was significantly greater in the bFGF group (43.8 c/hpf), compared with the control group (30.5 c/hpf; P<0.005). Specimens from the bFGF group (mean engraftment, 61,355 microm2) showed a 2.5-fold increase in hepatocyte engraftment as compared with control (24,197 microm2; P<0.002).
The angiogenic growth factor bFGF can be incorporated into degradable polymers used as delivery devices for hepatocyte transplantation. Implantation of these devices increases angiogenesis into the device and increases hepatocyte engraftment.
We revise the taxonomic status of Desmognathus wrighti, which occurs in the southern Appalachians of western North Carolina, eastern Tennessee, and southwest Virginia, USA, based on a combination of ...genetic, ecological, and morphometric analyses. Previously, we reported fixed differences in allozymic loci and mitochondrial DNA sequences between lineages geographically divided by the French Broad River basin at the level of species divergence. Here, we show that these two lineages also differ in ventral pigmentation and several measures of body size, including snout–vent length, body condition, and head width. In addition, spatially explicit ecological-niche analyses of climate at more than 400 collection localities spanning the range of D. wrighti indicate that the lineages separated by the French Broad River are in unique environmental niche space. Ecological niche models resolved that population localities north of the river were generally colder and drier than localities to the south, which suggests that divergent selection pressures may exist, in addition to isolation by distance, to drive the diversification of these two lineages. The name Desmognathus wrighti (King, 1936), for which the type locality is Mt. LeConte within the Great Smoky Mountains, Tennessee, was retained for all populations south and west of the French Broad River, while the name D. organi, with type locality at Whitetop Mountain, Virginia, was given to those populations north and east of the river.
Sequence data from a 597–base pair region of the mitochondrial DNA control region and data for 19 presumed allozyme loci were used to examine genetic structure and to detect gene flow among ...populations of southern red-backed voles (Myodes gapperi, formerly known as Clethrionomys gapperi) inhabiting spruce–fir “sky-islands” in the southern Appalachians. Allozyme data showed a significant heterozygote deficiency for most populations. Average individual heterozygosity varied among populations from 1.75% to 16.78% (X̄ ± SE = 8.63% ± 2.03%). FST values between any 2 sites ranged from 0.100 to 0.517 (X̄ ± SE = 0.296 ± 0.026), with a significant metapopulation FST value = 0.599. Nei's genetic distances (based on allozyme data) among spruce–fir habitats ranged from 0.037 to 0.310 (X̄ ± SE = 0.139 ± 0.079). Analysis of molecular variance permitted determination of the extent of geographic subdivision of mitochondrial haplotypes for 3 hierarchically organized sampling regimes: 14 high-altitude sample sites; 7 spruce–fir islands within which the sample sites are located; and whether sample sites were located south or north of the dominant, low-altitude barrier, the French Broad River. Genetic variation among groups and ΦST values were highly significant for all sampling regimes, indicating significant population structure at all hierarchical levels tested. Mantel's general regression test indicated that gene flow and genetic relationships fit an isolation-by-distance model. Since the Pleistocene, gene flow within the metapopulation of M. gapperi appears to have declined as a result of increasing distances between habitat islands and because of population bottlenecks.
Morbid obesity (MO) has reached epidemic proportions and is a major health problem in developed nations. In the adolescent with MO, early intervention can minimize obesity-related comorbidities, ...avoid premature mortality, improve quality of life, and prevent obesity-related diseases as these patients mature into adulthood. The primary surgical treatment of adolescent patients meeting National Institutes of Health criteria for bariatric surgery has been the gastric bypass (GB). Although GB has led to weight loss and improvement of comorbid conditions, concerns remain over the high incidence of postoperative complications and life-style–altering long-term sequelae of gastrointestinal tract reconstruction. Based on the excellent results from international adult series as well as the authors' own experience of more than 300 adult patients, laparoscopic adjustable gastric banding (LAGB) as an alternative to GB to eligible adolescents was offered.
After medical, psychologic, and nutritional screening, 4 patients (ages 17-19 years) with a body mass index of 40 or more (range, 40-61) who failed medical attempts at weight loss were selected for LAGB.
The operative time was 40 to 90 minutes. All patients were discharged on the day of surgery. There were no early complications. One patient had cholecystitis 6 months after surgery requiring laparoscopic cholecystectomy. For the 4 patients, the amount of excess weight loss was 57% at 30 months, 34% at 12 months, 87% at 7 months, and 15% at 4 months, respectively.
In this preliminary series of the US experience in the use of LAGB for the management of adolescents with MO, the lack of operative morbidity, short operative time/hospital stay, and encouraging initial weight loss mirror the adult experience and illustrate that the LAGB is a safe and effective alternative to GB. These encouraging results support further evaluation of LAGB as a surgical option in a comprehensive adolescent weight loss program.
Sequence variation of control region mitochondrial DNA, phylogenetic reconstruction, and analysis of molecular variance (AMOVA) were used to determine the degree of genetic structure of Yellow ...Warblers (Dendroica petechia) in the Galápagos Archipelago. When the Galápagos population was partitioned into subpopulations (by island), AMOVA indicated a nonsignificant level of genetic structure. The presence of the same haplotype on more than one island also indicated low genetic divergence among subpopulations. Using these sequences and those available in Genbank, we also determined the degree of divergence between the Galápagos Yellow Warbler population and other New World populations. Mean sequence divergence between the Galápagos population and Latin American populations was 3.7%, and between the Galápagos population and North American populations was 6.7%.
Nucleotide sequence data from the mitochondrial DNA (mtDNA) cytochrome-b gene and allozymic data were used to infer the evolutionary and biogeographic histories of New World tree squirrels of the ...genus Tamiasciurus. Phylogenetic analyses of the cytochrome-b data support the existence of 3 mtDNA lineages within Tamiasciurus: a western lineage consisting of populations of T. douglasii from western British Columbia (Canada), Washington, Oregon, and California, and T. mearnsi from northern Baja California (Mexico); a southwestern lineage consisting of populations of T. hudsonicus from New Mexico and Arizona; and a geographically widespread lineage comprising populations of T. hudsonicus from the remainder of the species' range. Levels of mtDNA sequence variation observed within and among populations of Tamiasciurus were small (0-2.4%), suggesting that contemporary geographic patterns of genetic variation in Tamiasciurus have been established relatively recently (i.e., in the Late Pleistocene). Allozyme analyses also support a close relationship among extant populations of Tamiasciurus. No fixed allelic differences were observed among the 3 recognized species and interspecific genetic distances (Nei's D) were substantially less than those typically observed between sibling species. Although differing from the current taxonomy in several respects, geographic patterns of genetic variation observed within Tamiasciurus are similar to those observed in a variety of North American boreal forest taxa and most likely reflect effects of forest fragmentation associated with glacial cycles of the Pleistocene.
We demonstrate with an experiment how molecules are a natural test bed for probing fundamental quantum thermodynamics. Single-molecule spectroscopy has undergone transformative change in the past ...decade with the advent of techniques permitting individual molecules to be distinguished and probed. We demonstrate that the quantum Jarzynski equality for heat is satisfied in this set-up by considering the time-resolved emission spectrum of organic molecules as arising from quantum jumps between states. This relates the heat dissipated into the environment to the free energy difference between the initial and final state. We demonstrate also how utilizing the quantum Jarzynski equality allows for the detection of energy shifts within a molecule, beyond the relative shift.
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