Examining Adolescent Tennis Participation in Contemporary China Using an Ecological Framework.

Physical activity and sport participation behaviors in children and adolescents are consistently shaped by surrounding ecological systems. Accumulating evidence highlights individual, family, peer, school and teacher, and macroenvironment elements such as policies that affect unstructured physical activity choices in youth populations. However, the reason for participation has not been fully interpreted from the perspective of the youth themselves, especially those from an Asian cultural background. In our study, we aimed to better understand the self-identified reasons for adolescents' participation in non-organized or spontaneous tennis practice in contemporary China. Twenty-six adolescents and informants were recruited in mainland China and participated in semi-structured interviews to provide thick descriptions of their continued tennis participation behaviors. Data were coded and analyzed via NVivo 12. Four themes emerged: (a) Individual characteristics and self-interpretations of tennis culture; (b) microsystems mediating adolescents' tennis participation; (c) barriers and obstacles impacting tennis participation; and (d) policies and macroenvironments. Adolescent tennis participation is a result of the integration effect of the sociocultural and ecological factors dominated by multifaceted ecological systems. As a particular vision of their physical activity experiences, adolescents' interpretation of tennis and their broader worldview has been continuously reshaped by concurrent sport and educational policies.

Fewer butterflies seen by community scientists across the warming and drying landscapes of the American West.

Uncertainty remains regarding the role of anthropogenic climate change in declining insect populations, partly because our understanding of biotic response to climate is often complicated by habitat loss and degradation among other compounding stressors. We addressed this challenge by integrating expert and community scientist datasets that include decades of monitoring across more than 70 locations spanning the western United States. We found a 1.6% annual reduction in the number of individual butterflies observed over the past four decades, associated in particular with warming during fall months. The pervasive declines that we report advance our understanding of climate change impacts and suggest that a new approach is needed for butterfly conservation in the region, focused on suites of species with shared habitat or host associations.

Temporary vascular shunting in vascular trauma: a 10-year review from a civilian trauma centre.

BACKGROUND: Temporary intravascular shunts (TIVSs) can replace immediate definitive repair as a damage control procedure in vascular trauma. We evaluated their use in an urban trauma centre with a high incidence of penetrating trauma. METHOD: A retrospective chart review of all patients treated with a TIVS in a single centre between January 2000 and December 2009. RESULTS: Thirty-five TIVSs were placed during the study period: 22 were part of a damage control procedure, 7 were inserted at a peripheral hospital without vascular surgical expertise prior to transfer, and 6 were used during fixation of a lower limb fracture with an associated vascular injury. There were 7 amputations and 5 deaths, 4 of the TIVSs thrombosed, and a further 3 dislodged or migrated. Twenty-five patients underwent definitive repair with an interposition graft, 1 primary anastomosis was achieved, and 1 extra-anatomical bypass was performed. Five patients with non-viable limbs had the vessel ligated. CONCLUSIONS: A TIVS in the damage control setting is both life- and limb-saving. These shunts can be inserted safely in a facility without access to a surgeon with vascular surgery experience if there is uncontrollable bleeding or the delay to definitive vascular surgery is likely to be more than 6 hours. A definitive procedure should be performed within 24 hours.

A ten year review of civilian iliac vessel injuries from a single trauma centre.

OBJECTIVE: To report the surgical management and outcome of iliac vessel (IV) injuries in a civilian trauma centre with a high incidence of penetrating trauma. DESIGN, PATIENTS AND METHODS: A retrospective record review of patients with IV injuries treated between January 2000 and December 2009. RESULTS: Sixty nine patients, 59 with gunshot wounds, sustained 108 iliac vessel injuries. Mean revised trauma and injury severity scores was 7.06 and 28.4, respectively. Twenty nine patients required damage control laparotomy. Common or external iliac arteries were repaired by primary repair (10), temporary shunt with delayed graft (6), interposition graft (5) or ligation if limb non-viable (3). Forty-seven patients had injuries to the common or external iliac vein, 42 were ligated. Mortality was 25% and 6 survivors required amputation. CONCLUSIONS: In a stable patient a primary arterial repair is preferred but a temporary shunt can be a life and limb saving option in the unstable patient. Ligating the common or external iliac veins is associated with a low incidence of prolonged leg swelling.

Elective intra-aortic balloon counterpulsation during a high risk liver resection.

SUMMARY: We present the case of a 65-year-old male with severe coronary artery disease and a single colorectal liver metastasis. An elective intra-aortic balloon pump (IABP) was inserted following induction of anaesthesia to reduce left ventricular workload during his liver resection. After an uneventful recovery he was discharged on day 5. We review the literature on the elective use of these devices in cardiac surgery in which it is becoming routine practice in high risk patients. However in non-cardiac surgery there have been only 15 published cases all in very high risk patients, with favourable outcomes. To our knowledge this is the first published case of the use of elective IABP during liver surgery.

Intensive graft-versus-host disease prophylaxis is required after unrelated-donor nonmyeloablative stem cell transplantation.

Nonmyeloablative stem cell transplantation (NST) harnesses the graft-versus-tumor effect while minimizing regimen-related toxicity, and can result in donor chimerism and remission. Acute graft-versus-host disease (GVHD) and infections are major complications after sibling NST. Toxicity of unrelated-donor (UD) NST and the most appropriate GVHD prophylaxis in this setting remain poorly defined. We describe 25 patients who received UD-NST conditioned with fludarabine and cyclophosphamide. The first six patients received cyclosporine (Cs) and mycophenolate mofetil (MMF) (n=5) or methotrexate (MTX) (n=1) as GVHD prophylaxis (group 1) and all developed grade III-IV acute GVHD. The next 19 patients received the same conditioning regimen with the addition of alemtuzumab, and all received Cs/MTX post-transplant. Engraftment and donor chimerism were achieved in all but one evaluable patient. In all, 15 patients died: five of six deaths in group 1 were attributable to acute GVHD, while deaths in group 2 were due to infection or progressive disease (P=0.05). The combination of Cs/MMF is inadequate GVHD prophylaxis for UD-NST. The use of Cs, MTX, and alemtuzumab eliminated severe acute GVHD; its impact on response merits further study.

Species boundaries, phylogeography and conservation genetics of the red-legged frog (Rana aurora/draytonii) complex.

The red-legged frog, Rana aurora, has been recognized as both a single, polytypic species and as two distinct species since its original description 150 years ago. It is currently recognized as one species with two geographically contiguous subspecies, aurora and draytonii; the latter is protected under the US Endangered Species Act. We present the results of a survey of 50 populations of red-legged frogs from across their range plus four outgroup species for variation in a phylogenetically informative, approximately 400 base pairs (bp) fragment of the mitochondrial cytochrome b gene. Our mtDNA analysis points to several major results. (1) In accord with several other lines of independent evidence, aurora and draytonii are each diagnosably distinct, evolutionary lineages; the mtDNA data indicate that they do not constitute a monophyletic group, but rather that aurora and R. cascadae from the Pacific northwest are sister taxa; (2) the range of the draytonii mtDNA clade extends about 100 km further north in coastal California than was previously suspected, and corresponds closely with the range limits or phylogeographical breaks of several codistributed taxa; (3) a narrow zone of overlap exists in southern Mendocino County between aurora and draytonii haplotypes, rather than a broad intergradation zone; and (4) the critically endangered population of draytonii in Riverside County, CA forms a distinct clade with frogs from Baja California, Mexico. The currently available evidence favours recognition of aurora and draytonii as separate species with a narrow zone of overlap in northern California.

Candidate gene analysis of metamorphic timing in ambystomatid salamanders.

Although much is known about the ecological significance of metamorphosis and metamorphic timing, few studies have examined the underlying genetic architecture of these traits, and no study has attempted to associate phenotypic variation to molecular variation in specific genes. Here we report on a candidate gene approach (CGA) to test specific loci for a statistical contribution to variation in metamorphic timing. Three segregating populations (SP1, SP2 and SP3) were constructed utilizing three species of paedomorphic Mexican ambystomatid salamander, including the axolotl, Ambystoma mexicanum. We used these replicated species to test the hypothesis that inheritance of alternate genotypes at two thyroid hormone receptor loci (TRalpha, TRbeta) affects metamorphic timing in ambystomatid salamanders. A significant TRalpha*SP effect indicated that variation in metamorphic timing may be influenced by TRalpha genotype, however, the effect was not a simple one, as both the magnitude and direction of the phenotypic effect depended upon the genetic background. These are the first data to implicate a specific gene in contributing to variation in metamorphic timing. In general, candidate gene approaches can be extended to any number of loci and to any organism where simple genetic crosses can be performed to create segregating populations. The approach is thus of particular value in ecological studies where target genes have been identified but the study organism is not one of the few well-characterized model systems that dominate genetic research.

Influence of circumcision and sexual behaviour on PSA levels in patients attending a sexually transmitted disease (STD) clinic.

Early age at first intercourse, increased number of sexual partners, lack of circumcision and history of sexually transmitted diseases (STDs) are associated with prostate cancer. There has been no investigation of the effect of these factors on prostate health at an early age. Previously collected serum samples from STD clinic attendees were tested retrospectively for anti-chlamydial antibodies, and prostate specific antigen (PSA) concentration. Patients at an STD clinic were interviewed regarding age of first intercourse, number of sexual partners and circumcision status. This was compared to clinical diagnosis, anti-chlamydial antibody titre and PSA concentration. The results showed: (1) that of patients with an anti-chlamydial antibody titre equal or greater than 1 in 64 (n=27) 37% had a PSA concentration greater than 0.8 ng/ml while those with a titre less than 1/64 (n=201) only 17% had a PSA >0.8 (P<0.05). (2) No association was found with circumcision status. (3) Early age of first intercourse and more than 20 sexual partners were associated with a synergistic increase in mean anti-chlamydial antibody titre and a mean PSA concentration of 1.2 ng/ml (95% CI 0.56-1.76). It is concluded that these results provide the first evidence that sexual behaviour related risk factors for prostate cancer do damage the prostate at an early age. Though they do not prove that infection is a cause of prostate cancer they do justify further research into the specificity of agents involved and impact of antibiotic treatment.Prostate Cancer and Prostatic Diseases (2001) 4, 228-231

A multilevel time-series model for the incidence of AIDS cases in Spain.

OBJECTIVE: The main aim of this research is to study the quantitative evolution of the incidence of AIDS in the 19 Spanish Communities. The hypothesis is that incidence follows a multilevel autoregressive model, where each Community shows random variability around a general process. METHOD: On the basis of official data on the number of existing AIDS cases, an autorregressive multilevel time-series model was developed. RESULTS AND CONCLUSIONS: Analysis shows that the hypothesis is supported, indicating that overall AIDS incidence in Spain has already reached a maximum and has a tendency to remain stable or to decline in future. Long term expected values have become stable in most Communities; a slight increase is expected only in Extremadura. However, this Community has a relatively sparse population, and its contribution on the overall Spanish incidence is small. Long term expected values are estimated to be around 152.99 new cases per million inhabitants per year. This value is slightly smaller than the maximum incidence, observed in 1994 (179.4 cases).

Cucumber mosaic virus is restricted from entering minor veins in transgenic tobacco exhibiting replicase-mediated resistance.

Transgenic tobacco plants expressing an altered form of the 2a replicase gene from cucumber mosaic virus (CMV) strain Fny exhibited a suppression of viral replication and restricted viral movement when inoculated mechanically or by insect vectors. Resistant plants could be infected, however, through a graft-union with an infected nontransformed plant. The infectious entity moved quickly through intergrafts of resistant tissue, indicating that it could move without replicating in the vascular system. Viral replication continued to be suppressed in systemically infected transgenic portions of grafted plants, as demonstrated by the synthesis of lower levels of viral RNA than in systemically infected nontransformed portions of the same grafted plants. Cell-to-cell spread within this tissue also occurred much more slowly than in nontransformed tobacco. Young inoculated levels of transgenic-resistant plants exhibited limited cell-to-cell virus movement, revealed as chlorotic lesions, but no long-distance virus movement occurred. The results of in situ hybridization studies on these lesions indicated that CMV RNA does not traffic from bundle-sheath cells to vascular parenchyma or companion cells in chlorotic lesions on the inoculated leaves of transgenic-resistant tobacco plants. The inhibition of long-distance movement was a consequence of restricted entry of the infectious entity into the vascular system.

Potency of endotoxin from bicarbonate dialysate compared with endotoxins from Escherichia coli and Shigella flexneri.

Endotoxin is a potent activator of the complement system and other host immunoregulators, including the cytokines, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6. In this study, the potency of an endotoxin from bicarbonate dialysate was compared with endotoxins from two enteric microorganisms, Shigella flexneri and Escherichia coli. Endotoxin concentrations were standardized for the three endotoxins by use of the Limulus amebocyte lysate turbidimetric assay. Endotoxin potency was assessed by the comparative plasma concentrations of tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 after an in vitro whole-blood challenge by each type of endotoxin. Blood collected from 10 hemodialysis patients was spiked with 0.1, 1, and 10 ng/mL of E. coli and Shigella endotoxin and with 1 and 10 ng/mL of bicarbonate dialysate endotoxin. After incubation, plasma was separated and frozen at -70 degrees C until assayed for cytokine concentrations. Dialysate endotoxin was found to be 10 to 100 times less potent than E. coli and Shigella endotoxins. It was concluded that there are significant differences in the potency of endotoxins from different strains of bacteria and that these differences should be noted when designing or evaluating studies on the clinical effects of endotoxins in hemodialysis settings.

The effect of uremia on tumor necrosis factor-alpha release after an in vitro whole-blood endotoxin challenge.

Uremia has been associated with immunologic aberrations, including anergy, increased susceptibility to infections, and reduced phagocytic activity of polymorphonuclear leukocytes. In this study, cytokine release in uremic and nonuremic blood after in vitro endotoxin stimulation was studied. Blood from nonuremic controls, chronic renal failure patients not on dialysis, and chronic hemodialysis patients predialysis and postdialysis was spiked with 10 ng/mL of Escherichia coli endotoxin and incubated for 2 and 26 h. Plasma tumor necrosis factor-alpha (TNF alpha) concentrations were determined by ELISA after each incubation period. To further study which uremic blood component may be responsible for enhanced release of TNF alpha, plasma and cellular components of chronic renal failure patients and controls were switched and then given an in vitro endotoxin stimulation (1 ng/mL). It was found that (1) TNF alpha release is enhanced by uremia and is exacerbated with progressive declines in renal function, (2) enhanced TNF alpha release is related to a blood cellular phenomenon induced by uremia, and (3) enhanced TNF alpha release in hemodialysis patients is associated with a prolonged stimulation and/or reduced plasma elimination of TNF alpha.

Normalization of uremic acidosis in hemodialysis patients with a high bicarbonate dialysate.

Uremic acidosis accompanies chronic renal failure in hemodialysis patients because of a retention of nonvolatile acids. Standard bicarbonate (39 mEq/L) and acetate (38 mEq/L) dialysates do not completely correct the acidosis. The acid-base and biochemical effect of a high-bicarbonate (42 mEq/L) dialysate was evaluated in 38 patients during high-efficiency and high-flux dialysis over 12 wk. All patients were dialyzed on standard bicarbonate dialysate before the study and for 8 wk after the study. In order to monitor potential excessive alkalosis, predialysis and postdialysis arterial blood gases were measured in seven patients who initially had a normal predialysis pH. Serum chemistries revealed no significant changes in predialysis BUN, calcium, ionized calcium, or phosphorus during the 12-wk study. There was no change in postdialysis ionized calcium or phosphorus. Predialysis and postdialysis serum total CO2 (STCO2) increased over the 12-wk study (P < 0.0001). By week 12, 75% of the hemodialysis patients had an STCO2 > 23 mEq/L and no patient had an STCO2 > 30 mEq/L predialysis. After the 8-wk washout, all chemistries were no different from prestudy concentrations. Predialysis blood gases in seven patients with normal predialysis HCO3 revealed a significant increase (P < 0.009) in PCO2 and HCO3 over the 12-wk study; predialysis pH and PO2 did not change. There was no significant change in postdialysis blood gases. It was concluded that: (1) a high-bicarbonate dialysate corrects predialysis acidosis in 75% of hemodialysis patients without causing progressive alkalemia, hypoxia, or hypercarbia; and (2) predialysis BUN, calcium, ionized calcium, and phosphorus are unaffected by high-bicarbonate dialysate.

Cytokine kinetics in an in vitro whole blood model following an endotoxin challenge.

Whole blood and peripheral blood mononuclear cell (PBMC) culture models have been used to study cytokine stimulation and release in vitro. In this study, we characterize the kinetics of the interleukins (IL-1 beta), (IL-6), (IL-8), and tumor necrosis factor-alpha (TNF-alpha) following an endotoxin (ET) challenge using our in vitro whole blood model. Whole blood samples from 10 healthy volunteers were studied. All cytokines were measured by enzyme-linked immunosorbent assay. Peak concentrations of TNF-alpha occurred 2 h after ET challenge followed by a rapid decline in free plasma TNF-alpha concentration (half-life 18.2 min). IL-1 beta was not significantly elevated until 4 h after ET challenge. IL-8 was elevated 1 h after ET challenge. IL-6 concentration exhibited a biphasic peak occurring at 6 and 74 h after ET challenge. We conclude that (1) our whole blood in vitro model produces cytokine release kinetics similar to those reported in vivo, and (2) the presence of either binding proteins or cellular metabolism of TNF-alpha in whole blood produces a similar plasma half-life to that observed in vivo.

A prospective study of pyrogenic reactions in hemodialysis patients using bicarbonate dialysis fluids filtered to remove bacteria and endotoxin.

Pyrogenic reactions (PR) are a well-recognized complication of hemodialysis and have been associated with dialyzer reuse, high-flux dialysis, and bicarbonate dialysate. However, the roles of bacteria and endotoxin in dialysate for producing PR are not well defined. To determine the effect of removing most bacteria and endotoxin from the dialysate on the incidence of PR, a cohort of chronic hemodialysis patients receiving high-flux, high-efficiency, or conventional hemodialysis at three centers with bicarbonate dialysis fluids that had been filtered with a polysulfone high-flux hemodialyzer was prospectively studied. Unfiltered bicarbonate concentrate had median bacterial and endotoxin concentrations of 479,000 CFU/mL and 39,800 pg/mL, respectively. After filtration of the bicarbonate concentrate at the central proportioner, dialysate had a median 9.2 CFU/mL of bacteria and 17.8 pg/mL of endotoxin. Dialysate filtered at individual proportioning dialysis machines had a median 0.001 CFU/mL of bacteria and 0.19 pg/mL of endotoxin. Nine PR were identified among 303 patients after 28,007 hemodialysis treatments (0.3 PR/1,000 treatments). The rate of PR was similar for the three hemodialysis treatment modalities and for first-use compared with reused dialyzers. Although the PR rate in this study was lower (P = 0.046) than the PR rate of a previous study with unfiltered dialysis fluids (0.7 PR/1,000 treatments), it represents a difference of only 10 PR in over 28,000 treatments. It was concluded that filtration of hemodialysis fluids is efficacious in removing bacterial and endotoxin contamination and can result in a lower incidence of PR in patients receiving high-flux, high-efficiency, or conventional hemodialysis.

The effects of calcium carbonate as the sole phosphate binder in combination with low calcium dialysate and calcitriol therapy in chronic hemodialysis patients.

Alternative phosphate binders, such as CaCO3, have been shown to be effective in the control of phosphate (P) retention in hemodialysis patients (HDP). Additionally, both oral (POC) and iv (IVC) calcitriol are purported to be of benefit in the control of secondary hyperparathyroidism. This investigation was undertaken to determine: (1) the effectiveness of CaCO3 as the sole P binder in combination with low (2.5 mEq/L) Ca dialysate; (2) the effects of discontinuing Al(OH)3 binders on both unstimulated and stimulated Al concentrations; and (3) the comparative parathyroid hormone (PTH) response to both POC and IVC in a large group of hemodialysis patients. One hundred ninety-four HDP completed part 1 of the study where CaCO3 was substituted for Al(OH)3 as the sole P binder for 6 months. A cohort of 49 HDP was given desferoximine (40 mg/kg) initially and 10 months after using CaCO3. In part 2, 54 HDP were given POC and 97 HDP were given IVC in dosages of 0.25 to 0.5 micrograms/day and 1.5 to 6.0 micrograms/wk, respectively, for an additional 6 months. In part 1, Ca and P were not different from baseline values observed with Al(OH)3 therapy. Ionized Ca increased (P < 0.05) and PTH decreased (P < 0.001) during CaCO3 therapy without vitamin D. In part 2, PTH declined 23% with IVC and was unchanged with POC in equivalent dosages (P < 0.05) at 3 months. By 6 months, PTH declined a total of 54% with IVC and was unchanged with POC. Ca, ionized Ca, P, and serum calcitriol were greater (P < 0.05) in the IVC group at 6 months. Serum Al concentrations for the entire 194 HDP fell 65% (P < 0.0001) over 12 months. In the 49 HDP cohort, serum Al fell 43.6% (P < 0.001) and stimulated Al concentrations decreased 68.7% (P < 0.0001) after 10 months. We conclude that: (1) CaCO3 is as effective as Al(OH)3 in controlling P, (2) a small decrease in PTH is observed with CaCO3 alone, (3) serologic evidence of Al excess is virtually eliminated, (4) PTH suppression with IVC is superior to that seen with POC in equivalent doses.