Low genetic diversity in pygmy blue whales is due to climate-induced diversification rather than anthropogenic impacts.

Unusually low genetic diversity can be a warning of an urgent need to mitigate causative anthropogenic activities. However, current low levels of genetic diversity in a population could also be due to natural historical events, including recent evolutionary divergence, or long-term persistence at a small population size. Here, we determine whether the relatively low genetic diversity of pygmy blue whales (Balaenoptera musculus brevicauda) in Australia is due to natural causes or overexploitation. We apply recently developed analytical approaches in the largest genetic dataset ever compiled to study blue whales (297 samples collected after whaling and representing lineages from Australia, Antarctica and Chile). We find that low levels of genetic diversity in Australia are due to a natural founder event from Antarctic blue whales (Balaenoptera musculus intermedia) that occurred around the Last Glacial Maximum, followed by evolutionary divergence. Historical climate change has therefore driven the evolution of blue whales into genetically, phenotypically and behaviourally distinct lineages that will likely be influenced by future climate change.

Hybridization of Southern Hemisphere blue whale subspecies and a sympatric area off Antarctica: impacts of whaling or climate change?

Understanding the degree of genetic exchange between subspecies and populations is vital for the appropriate management of endangered species. Blue whales (Balaenoptera musculus) have two recognized Southern Hemisphere subspecies that show differences in geographic distribution, morphology, vocalizations and genetics. During the austral summer feeding season, the Antarctic blue whale (B. m. intermedia) is found in polar waters and the pygmy blue whale (B. m. brevicauda) in temperate waters. Here, we genetically analyzed samples collected during the feeding season to report on several cases of hybridization between the two recognized blue whale Southern Hemisphere subspecies in a previously unconfirmed sympatric area off Antarctica. This means the pygmy blue whales using waters off Antarctica may migrate and then breed during the austral winter with the Antarctic subspecies. Alternatively, the subspecies may interbreed off Antarctica outside the expected austral winter breeding season. The genetically estimated recent migration rates from the pygmy to Antarctic subspecies were greater than estimates of evolutionary migration rates and previous estimates based on morphology of whaling catches. This discrepancy may be due to differences in the methods or an increase in the proportion of pygmy blue whales off Antarctica within the last four decades. Potential causes for the latter are whaling, anthropogenic climate change or a combination of these and may have led to hybridization between the subspecies. Our findings challenge the current knowledge about the breeding behaviour of the world's largest animal and provide key information that can be incorporated into management and conservation practices for this endangered species.

Role of hepatic portocholecystostomy ('gallbladder Kasai') in treating infants with biliary atresia.

The aim of this study is to compare liver function and cholangitis episodes during the first year postoperatively between patients who undergo hepatic portocholecystostomy (HPC) and patients who undergo hepatic portoenterostomy (HPE). Records of six patients who underwent HPC for biliary atresia (BA) and 27 patients who underwent HPE for BA were reviewed retrospectively. Comparison was done of the patient's total bilirubin, albumin, and international normalized ratio values preoperatively and at 3 months, 6 months, and 1 year postoperatively. Comparison was also done of the occurrence of ascending cholangitis during the first year postoperatively and in rates of transplant and mortality during long-term follow-up. Preoperative laboratory values between the two groups were not significantly different. At 6 months, the patients who underwent HPC had significantly lower total bilirubin levels compared with those who underwent HPE (HPC 0.8 +/- 0.96, n = 4; HPE 4.93 +/- 7.73, n = 21; P < 0.05). No other laboratory values or rates of ascending cholangitis, transplant, or mortality showed a significant difference. Those patients who underwent HPC had significantly lower total bilirubin levels at 6 months postoperatively. This may suggest that HPC may be a superior operative technique for patients who are candidates for the operation.

Song variation of the South Eastern Indian Ocean pygmy blue whale population in the Perth Canyon, Western Australia.

Sea noise collected over 2003 to 2017 from the Perth Canyon, Western Australia was analysed for variation in the South Eastern Indian Ocean pygmy blue whale song structure. The primary song-types were: P3, a three unit phrase (I, II and III) repeated with an inter-song interval (ISI) of 170-194 s; P2, a phrase consisting of only units II & III repeated every 84-96 s; and P1 with a phrase consisting of only unit II repeated every 45-49 s. The different ISI values were approximate multiples of each other within a season. When comparing data from each season, across seasons, the ISI value for each song increased significantly through time (all fits had p << 0.001), at 0.30 s/Year (95%CI 0.217-0.383), 0.8 s/Year (95%CI 0.655-1.025) and 1.73 s/Year (95%CI 1.264-2.196) for the P1, P2 and P3 songs respectively. The proportions of each song-type averaged at 21.5, 24.2 and 56% for P1, P2 and P3 occurrence respectively and these ratios could vary by up to ± 8% (95% CI) amongst years. On some occasions animals changed the P3 ISI to be significantly shorter (120-160 s) or longer (220-280 s). Hybrid song patterns occurred where animals combined multiple phrase types into a repeated song. In recent years whales introduced further complexity by splitting song units. This variability of song-type and proportions implies abundance measure for this whale sub population based on song detection needs to factor in trends in song variability to make data comparable between seasons. Further, such variability in song production by a sub population of pygmy blue whales raises questions as to the stability of the song types that are used to delineate populations. The high level of song variability may be driven by an increasing number of background whale callers creating 'noise' and so forcing animals to alter song in order to 'stand out' amongst the crowd.

Video-assisted transumbilical Meckel's diverticulectomy in children.

The treatment of Meckel's diverticulum (MD) in children is resection. Some data exist for the use of laparoscopic resection. The Video-Assisted Transumbilical (VAT) single-trocar technique has been recently described for appendectomy. We also have used this technique for the resection of MD. The purpose of this study is to report our experience with laparoscopic-assisted resection of MD using both the three-trocar and the single-trocar techniques. The Institutional Review Board approved our retrospective chart review of all patients with the diagnosis of MD. Only the cases that were treated via laparoscopy were included. Technique of resection was at the discretion of the surgeon. Nine patients underwent laparoscopic resection of an MD from 2000 to 2005. Four patients underwent the three-trocar technique (LAP n = 4) and the remaining five underwent the video-assisted transumbilical single-trocar technique (VAT n = 5) procedure. Indications for surgery included gastrointestinal bleeding (VAT n = 3; LAP n = 2), malrotation (LAP n = 2), intussusception (VAT n = 1), and abdominal pain (VAT n = 1). All patients were male, and ages ranged from 7 months to 17 years for the VAT group and 8 months to 15 years for the LAP group. The average length of surgery for the LAP versus VAT was 128 minutes (94-170 minutes) and 81.4 minutes (42-96 minutes) respectively. Of the five patients undergoing LAP, two Ladd's procedures and three appendectomies were included during the same anesthesia. Only a single appendectomy procedure was performed during a VAT. The average time until full feeds with the LAP and VAT was 4.3 days (2-8 days) and 2.0 days (1-3 days) respectively. The overall length of stay with LAP versus VAT was 4.3 days (2-8 days) and 3.7 days (2-5 days). Only one case using the LAP method required conversion to an open laparotomy. Though no randomized trial for the removal of MD exists, our data suggest that the use of laparoscopy for removal of both symptomatic and asymptomatic MD is safe and effective. Additionally, the one trocar technique is feasible and may be beneficial in terms of fewer incisions and operative costs; however, more patients need to be studied.

From conservation genetics to conservation genomics: a genome-wide assessment of blue whales (Balaenoptera musculus) in Australian feeding aggregations.

Genetic datasets of tens of markers have been superseded through next-generation sequencing technology with genome-wide datasets of thousands of markers. Genomic datasets improve our power to detect low population structure and identify adaptive divergence. The increased population-level knowledge can inform the conservation management of endangered species, such as the blue whale (Balaenoptera musculus). In Australia, there are two known feeding aggregations of the pygmy blue whale (B. m. brevicauda) which have shown no evidence of genetic structure based on a small dataset of 10 microsatellites and mtDNA. Here, we develop and implement a high-resolution dataset of 8294 genome-wide filtered single nucleotide polymorphisms, the first of its kind for blue whales. We use these data to assess whether the Australian feeding aggregations constitute one population and to test for the first time whether there is adaptive divergence between the feeding aggregations. We found no evidence of neutral population structure and negligible evidence of adaptive divergence. We propose that individuals likely travel widely between feeding areas and to breeding areas, which would require them to be adapted to a wide range of environmental conditions. This has important implications for their conservation as this blue whale population is likely vulnerable to a range of anthropogenic threats both off Australia and elsewhere.

Glucocorticoid rescue for late-phase acute respiratory distress syndrome in trauma/surgical critical care patients.

High-dose glucocorticoid therapy (GCT) for the late fibroproliferative phase of acute respiratory distress syndrome (ARDS) is controversial and has shown mixed results in medical patients. No studies have evaluated GCT in trauma/surgical critical care patients. The purpose of this study is to review the outcomes of trauma/surgical critical care patients with refractory ARDS treated with GCT. From January 2001 through September 2005, a pharmacy log was used to identify critically ill trauma/surgical patients in refractory ARDS (7 males and 2 females) who received GCT in an attempt to salvage them. GCT consisted of 200 mg intravenous methylprednisolone bolus for one dose and then 3 mg/kg per day divided every 6 hours for 6 weeks or until weaned off the ventilator. All patients as well as the survivors were analyzed. Outcome data was analyzed with SPSS (Chicago, IL) and the paired sample test. A P value < or = 0.05 was considered significant. Data is presented as mean +/- standard deviation. The Institutional Review Board approved this retrospective chart review. Seven patients (6 males and 1 female; age, 31 +/- 16 years) survived (78%), weaned off of the ventilator, and were discharged from the hospital. The 2 deaths were secondary to refractory respiratory failure as well as cardiac arrest (n = 1) and anoxic brain injury from septic hypotension (n = 1). In survivors (n = 7), hospital length of stay (LOS) and intensive care unit LOS was 71 +/- 30 days and 53 +/- 16 days, respectively. Duration of GCT administration was 17 +/- 6.4 days (range, 11-30 days). Ventilator time before GCT, during GCT, and after GCT was 22 +/- 8.4, 15 +/- 7.5, and 1.6 +/- 6.0 days, respectively. During GCT, 8 patients developed pneumonia, 5 had urinary tract infection, and 3 had bacteremia. All infections were effectively treated with broad-spectrum antibiotics, except in one patient who died of sepsis. PaO2/FIO2 ratio just before and after GCT was 100 +/- 36 and 247 +/- 56, respectively (n = 7; P < 0.001). Sequential organ failure assessment score just before and after GCT was 9.1 +/- 2.3 and 5.0 +/- 1.6, respectively (n = 7; P < 0.001). GCT rescue may have a role in salvaging critically ill trauma/surgical critical care patients in late-stage ARDS. More patients, however, need to be studied.

Video-assisted thoracoscopic division of vascular rings in pediatric patients.

Vascular rings are usually repaired via left thoracotomy. We report our series of pediatric patients with vascular rings that were repaired thoracoscopically. From February 2002 to September 2004, 13 patients underwent video-assisted thoracoscopic surgical techniques (VATS) division of their vascular ring. Chest magnetic resonance arterography (MRA) and/or computed tomographic arteriography (CTA) were used to evaluate the vascular ring in most patients. Patients were chosen for VATS repair based on surgeon's choice and type of vascular ring. Data are expressed as mean +/- SD. The Children's Healthcare of Atlanta Institutional Review Board approved this retrospective chart review. Age and weight was 1.5 +/- 1.8 years (range: 4 months - 17 years) and 16.0 +/- 12.5 kg (range: 6.0 - 22.1 kg), respectively (n = 13). Associated diseases included congenital heart disease (n = 2). Symptoms included respiratory complaints (n = 6), dysphagia (n = 2), dysphagia and shortness of breath (n = 1), pneumonia (n = 2), tracheal deviation (n = 1), and one patient was asymptomatic. Vascular ring types included double aortic arch (n = 4) and right aortic arch with an aberrant left subclavian artery and a left ligamentum arteriosum (n = 9). Operating time was 70 +/- 20 minutes (range: 46 - 122 minutes). One patient had to be opened because of a large arch. Length of stay was 1.9 +/- 0.9 days (range: 1 - 3 days). There were no complications, and all patients improved clinically at follow-up. Thoracoscopic repair of certain types of vascular rings seems to be safe and effective in children. More patients, however, need to be studied.

Effect of bladder wall thickness on miniature pneumatic artificial muscle performance.

Pneumatic artificial muscles (PAMs) are actuators known for their high power to weight ratio, natural compliance and light weight. Due to these advantages, PAMs have been used for orthotic devices and robotic limbs. Small scale PAMs have the same advantages, as well as requiring greatly reduced volumes with potential application to prostheses and small scale robotics. The bladder of a PAM affects common actuator performance metrics, specifically: blocked force, free contraction, hysteresis, and dead-band pressure. This paper investigates the effect that bladder thickness has on static actuation performance of small scale PAMs. Miniature PAMs were fabricated with a range of bladder thicknesses to quantify the change in common actuator performance metrics specifically: blocked force, free contraction, and dead-band pressure. These PAMs were then experimentally characterized in quasi-static conditions, where results showed that increasing bladder wall thickness decreases blocked force and free contraction, while dead-band pressure increases. A nonlinear model was then applied to determine the structure of the stress-strain relationship that enables accurate modeling and the minimum number of terms. Two nonlinear models are compared and the identified parameters are analyzed to study the effect of the bladder thickness on the model.

[Anatomo-functional substrate of high risk arrhythmia after myocardial infarct]. / Sustrato anatomofuncional de las arritmias de alto riesgo tras el infarto de miocardio.

Ventricular arrhythmias detected in the late-hospital phase of myocardial infarction have been identified as a risk factor for sudden death, being their prognostic value independent of ventricular function. However, relations between both factors are not clarified. In order to study hypothetic associations between ventricular arrhythmias and some clinical, hemodynamic and angiographic variables, 60 patients (52 males, 8 females) underwent 24-hour Holter recordings and cardiac catheterization with left ventricular and coronary angiographies, 3-5 weeks after hospital admission. Past history data, acute phase complications and hemodynamic and angiographic results were compared between patients with and without significant ventricular arrhythmias during Holter monitoring (10 or more PVC's/hour and/or repetitive forms). No significant differences were found between both groups neither in mean age nor in the incidence of previous angina or infarction, cerebral ischemia, diabetes, lipid disorders or subjective feeling of being under psychological stress. Prior history of arterial hypertension was, however, significantly more frequent in patients with ventricular arrhythmias (53.3% vs 17.8%; p = 0.0183). No differences were observed in the localization of the infarct or in the complications during the acute phase (CPK peak, Killip's score, angina after 24 hours of evolution, intraventricular or A-V conduction disorders and supraventricular and ventricular arrhythmias). Among hemodynamic data, only left ventricular and aortic systolic pressures were different in both groups, being significantly higher in patients with ventricular arrhythmias. There were not differences in left ventricular segmentary contraction and in number of coronary vessels involved. To conclude, significant ventricular arrhythmias were recorded in 25% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Syncope: epidemiological characteristics of a hospital series]. / Síncope: características epidemiológicas de una serie hospitalaria.

Three hundred hospital patients with syncope (193 males and 107 females, mean age 61 +/- 17 years) were prospectively evaluated with a standard protocol. Associated diseases were found in 76.7% of cases. The incidence of heart diseases was 50.8% in males vs 32.7% in females (p less than 0.003). The cause of syncope was diagnosed in 250 patients (84%). The diagnosis was made at initial evaluation in 101 patients (group A); in the remaining patients (group B), no diagnosis was made in 25% (16.6% of the overall series) despite a wide array of investigations. Syncope due to arrhythmia was diagnosed in 57.6% (group A: 91.1% group B: 40.7; p less than 0.0001); cardiac syncope not due to arrhythmia was diagnosed in 4%, and other types of syncope in 21.6% (group A; 6.9%; group B: 29.1%; p less than 0.0001). It is concluded that a) the hospital population of patients with syncope represents a subgroup of advanced age and a high incidence of associated diseases; b) one third of patients were diagnosed at the initial evaluation, whereas in 25% of the remaining ones no diagnosis was obtained, and c) in these patients, arrhythmia is the most likely cause of syncope.

A comparison of private and public dental students' perceptions of extramural programming.

This project was undertaken to compare the opinions of private and public dental school students' perceptions concerning extramural programming, which is defined as any aspect of the curriculum in which undergraduate dental students provide dental care outside the main dental facility. A survey instrument was used to collect data from undergraduate students at a private (N = 267; 88.4 percent response rate) and at a public (N = 213; 67.2 percent response rate) dental school. When asked to rate the value of various extramural sites in making them a better dentist, both groups rated private dental offices the most valuable and prisons the least valuable. When questioned about the amount of time students should spend each year in extramural programming, private students, overall, desired 34 percent more time than did public students. When asked what percentage of the total time spent in extramural programming students should spend providing various categories of dental care, public school students thought 26 percent more time should be spent rendering preventive services/health education than did the private students. The private students indicated a stronger desire (13 percent more) for rendering clinical services than did public students. Both private and public students were most likely to enter group private practice after graduation. The increasing interest in community-based programs makes the information gained from this study useful for future curriculum planning.

Migratory movements of pygmy blue whales (Balaenoptera musculus brevicauda) between Australia and Indonesia as revealed by satellite telemetry.

In Australian waters during the austral summer, pygmy blue whales (Balaenoptera musculus brevicauda) occur predictably in two distinct feeding areas off western and southern Australia. As with other blue whale subspecies, outside the austral summer their distribution and movements are poorly understood. In order to describe the migratory movements of these whales, we present the satellite telemetry derived movements of eleven individuals tagged off western Australia over two years. Whales were tracked from between 8 and 308 days covering an average distance of 3,009±892 km (mean ± se; range: 832 km-14,101 km) at a rate of 21.94±0.74 km per day (0.09 km-455.80 km/day). Whales were tagged during March and April and ultimately migrated northwards post tag deployment with the exception of a single animal which remained in the vicinity of the Perth Canyon/Naturaliste Plateau for its eight day tracking period. The tagged whales travelled relatively near to the Australian coastline (100.0±1.7 km) until reaching a prominent peninsula in the north-west of the state of Western Australia (North West Cape) after which they travelled offshore (238.0±13.9 km). Whales reached the northern terminus of their migration and potential breeding grounds in Indonesian waters by June. One satellite tag relayed intermittent information to describe aspects of the southern migration from Indonesia with the animal departing around September to arrive in the subtropical frontal zone, south of western Australia in December. Throughout their migratory range, these whales are exposed to impacts associated with industry, fishing and vessel traffic. These movements therefore provide a valuable tool to industry when assessing potential interactions with pygmy blue whales and should be considered by conservation managers and regulators when mitigating impacts of development. This is particularly relevant for this species as it continues to recover from past exploitation.

Laparoscopic versus open reduction of intussusception in children: experience over a decade.

BACKGROUND: Intussusception is a common cause of bowel obstruction in children, which sometimes necessitates operative reduction and or resection. We report our series of patients with intussusception who were treated laparoscopically (LAP group) compared with exploratory laparotomy (OPEN group). SUBJECTS AND METHODS: After institutional review board approval, a retrospective review was performed evaluating outcomes for patients requiring surgical reduction of intussusception over a 10-year period. Analysis was based on intent to treat, and technique of exploration was surgeon's choice. Data were analyzed with the Wilcoxon rank sum test and chi-squared test where appropriate. P≤.05 was considered significant. RESULTS: During the time period studied, there were 92 patients treated surgically for intussusception: 65 LAP and 27 OPEN. Conversion to the open procedure was required for 21 patients in the LAP group, and of those, 6 required bowel resection. Seven of the patients who were started in the OPEN group ultimately required bowel resection. Operative time, length of hospital stay, time to full feeds, and total days of narcotics were all significantly shorter for the LAP group compared with the OPEN group (P=.003, P=.001, P=.001, and P=.004, respectively). A pathologic lead point was found in 14% of LAP and 15% of OPEN cases. In a subset analysis, 33% of patients who were converted from the LAP group to the open procedure had a pathologic lead point. Complication rates between the LAP and OPEN groups were comparable. CONCLUSIONS: Laparoscopy appears to be a safe and effective technique for reducing intussusception in children. The laparoscopic cases had shorter operative time, shorter time to full feeds, lower requirement for intravenous narcotics, and earlier discharges.

Estimating cetacean carrying capacity based on spacing behaviour.

Conservation of large ocean wildlife requires an understanding of how they use space. In Western Australia, the humpback whale (Megaptera novaeangliae) population is growing at a minimum rate of 10% per year. An important consideration for conservation based management in space-limited environments, such as coastal resting areas, is the potential expansion in area use by humpback whales if the carrying capacity of existing areas is exceeded. Here we determined the theoretical carrying capacity of a known humpback resting area based on the spacing behaviour of pods, where a resting area is defined as a sheltered embayment along the coast. Two separate approaches were taken to estimate this distance. The first used the median nearest neighbour distance between pods in relatively dense areas, giving a spacing distance of 2.16 km (± 0.94). The second estimated the spacing distance as the radius at which 50% of the population included no other pods, and was calculated as 1.93 km (range: 1.62-2.50 km). Using these values, the maximum number of pods able to fit into the resting area was 698 and 872 pods, respectively. Given an average observed pod size of 1.7 whales, this equates to a carrying capacity estimate of between 1187 and 1482 whales at any given point in time. This study demonstrates that whale pods do maintain a distance from each other, which may determine the number of animals that can occupy aggregation areas where space is limited. This requirement for space has implications when considering boundaries for protected areas or competition for space with the fishing and resources sectors.

Antimicrobial decapeptide KSL-W attenuates Candida albicans virulence by modulating its effects on Toll-like receptor, human ß-defensin, and cytokine expression by engineered human oral mucosa.

We investigated the toxicity of synthetic antimicrobial decapeptide KSL-W on normal human gingival epithelial cell cultures, its effect on Candida albicans adhesion and growth, and the activation of epithelial cell innate immunity. Our results indicate that KSL-W had no toxic effect on cell adhesion or growth, suggesting its safe use with human cells. Pre-treating C. albicans with KSL-W attenuated the yeast's virulence as demonstrated by its reduced adhesion and growth on engineered human oral mucosa epithelium and the subsequent decreased expression of some innate defense molecules by targeted epithelial cells. Indeed, the expression of Toll-like receptors and human ß-defensins was reduced in tissues infected with KSL-W-treated Candida. Proinflammatory cytokine secretion (IL-1ß and IL-6) by the epithelial cells was also regulated by KSL-W in a manner similar to that of antifungal molecule amphotericin B. These findings therefore show that KSL-W is safe for use with human cells and is able to attenuate Candida virulence by modulating its effects on host innate immunity. This study proposes the potential application of KSL-W peptide as an alternative antifungal agent.

Laparoscopic versus open repair of congenital duodenal obstruction in infants.

BACKGROUND/PURPOSE: Congenital duodenal obstruction (CDO) is traditionally managed via laparotomy. Laparoscopy has been suggested as an alternative; however, few series have described this in neonatal CDO. We report our series of CDO repaired laparoscopically compared to laparotomy. METHODS: After Institutional Review Board approval, a retrospective review was performed on patients with CDO who were presented between October 2001 and July 2010. Duodenal obstruction was managed laparoscopically (LAP) or via an open approach (OPEN) based on the surgeon's choice. Data were analyzed by intention to treat and were expressed as median±range. RESULTS: Twenty-two neonates underwent laparoscopy and 36 had a traditional laparotomy for management of CDO. Associated diseases included Down's syndrome (n=26), congenital heart disease (n=29), and malrotation (n=16). Median age was 4 days (range: 1-310) for LAP and 3 days (range: 0-166) for OPEN (P=.04). Gestational age and weight were similar (P=.335 and .378). The CDO was due to atresia (n=32), web (n=16), and annular pancreas (n=10). Median operative time for LAP was 116 minutes with a range of 73-164 while median time for OPEN was 103 minutes with a range of 71-220 (P=.013). There was no difference in time to full feedings (P=.69) or postoperative length of stay (P=.682). Ventilation time was 2 days with a range of 0-149 for LAP and ventilation time was 4 days with a range of 0-9 for OPEN (P=.02). Complication rates between the groups were similar. CONCLUSION: In the hands of a skilled surgeon, laparoscopy appears to be a safe and effective technique in managing CDO in neonates. In this retrospective study, laparoscopic management of CDO appeared to allow a shorter postoperative ventilator requirement with similar length of stay and time to full feedings. Operative time was slightly longer in the LAP group. Formal prospective trials are recommended to validate these findings.

Genetic composition of contemporary swine influenza viruses in the West Central region of the United States of America.

BACKGROUND: Because of continuous circulation in different animal species and humans, influenza viruses have host-specific phenotypic and genetic features. Reassortment of the genome segments can significantly change virus phenotype, potentially generating virus with pandemic potential. In 2009, a new pandemic influenza virus emerged. OBJECTIVES: In this study, we attempted to find precursor viruses or genes of pandemic H1N1 influenza 2009 among 25 swine influenza viruses, isolated in the West Central region of the United States of America (USA), between 2007 and 2009. The Phylogenetically Similar Triple-Reassortant Internal Genes (PSTRIG) cassette of all the viruses studied here as well as the PSTRIG cassette of pandemic H1N1 viruses have close but equidistant phylogenetic relationships to the early triple-reassortant swine H3N2 influenza A isolated in the USA in 1998. METHODS: Samples (nasal swabs and lung tissue lavage) were taken from swine with or without clinical signs of respiratory disease via farmer-funded syndromic surveillance. All studied viruses were isolated in Madin-Darby Canine Kidney cell cultures from the above-mentioned samples according to standard protocols recommended for influenza virus isolation. Sequences were obtained using BigDye Terminator v3.1 Cycle Sequencing kit. Phylogenetic trees were built with MEGA 4.0 software using maximum composite likelihood algorithm and neighbor-joining method for tree topology reconstruction. RESULTS: Among the 25 viruses studied, we have not found any gene segments of Eurasian origin. Our results suggest that pandemic H1N1 viruses diverged and are not directly descended from swine viruses that have been circulating in USA since 1998.

Retropleural teratoma presenting as an abdominal mass in a 9-month-old boy.

BACKGROUND: Teratomas are rare tumors that present most commonly in the anterior mediastinum and retroperitoneum. To date, the retropleural primary site has not been reported. CASE PRESENTATION: A 9-month-old boy presented with a large, painless, right-sided abdominal mass. Laboratory values, including tumor markers α-fetoprotein and ß-human chorionic gonadotropin, were within normal limits. Diagnostic imaging, including abdominal ultrasound, computed tomographic scan, and magnetic resonance imaging, suggested a large retroperitoneal mass consistent with a teratoma. Because the mass was thought to be arising from the retroperitoneum, an abdominal approach was chosen. After adequate exposure, it became clear that the tumor was arising from above the diaphragm. The diaphragm was incised, and the pleural cavity was entered. The tumor was found in the retropleural space where it was dissected away from the inferior vena cava, aorta, and chest wall. The patient recovered without complications. RESULTS: Histologic examination revealed a mature cystic teratoma with no malignant features. The patient has been disease-free at 7-year follow-up, based upon both clinical examination and diagnostic imaging. CONCLUSION: This is the first case report of a teratoma arising from the retropleural space. Preoperative imaging may be inaccurate for guiding surgical planning because the diaphragm may not be clearly visualized with current diagnostic techniques. Surgeons should be cautious regarding the location of tumors that arise near the diaphragm and should plan surgical resection carefully.