Impact of reduced-representation sequencing protocols on detecting population structure in a threatened marsupial.

Reduced-representation sequencing methods have wide utility in conservation genetics of non-model species. Several methods are now available that reduce genome complexity to examine a wide range of markers in a large number of individuals. We produced two datasets collected using different laboratory techniques, comprising a common set of samples from the greater bilby (Macrotis lagotis). We examined the impact of differing data filtering thresholds on downstream population inferences. We found that choice of restriction enzyme and data filtering thresholds, especially the rate of allowable missing data, impacted our ability to detect population structure. Estimates of FST were robust to alterations in laboratory and bioinformatic protocols while principal coordinates and STRUCTURE analyses showed variation according to the number of loci and percent missing data. We advise researchers using reduced-representation sequencing in conservation projects to examine a range of data thresholds, and follow these through to downstream population inferences. Multiple measures of population differentiation should be used in order to fully understand how data filtering thresholds influence the final dataset, paying particular attention to the impact of allowable missing data. Our results indicate that failure to follow these checks could impact conclusions drawn, and conservation management decisions made.

DNA based method for determining source country of the short beaked echidna (Tachyglossus aculeatus) in the illegal wildlife trade.

The illegal trade in wild animals being sold as 'captive bred' is an emerging issue in the pet and zoo industry and has both animal welfare and conservation implications. DNA based methods can be a quick, inexpensive, and definitive way to determine the source of these animals, thereby assisting efforts to combat this trade. The short beaked echidna (Tachyglossus aculeatus) is currently one of the species suspected to be targeted in this trade. As this species is distributed throughout Australia and in New Guinea (currently comprising of five recognised sub-species), this project aimed to develop a DNA based method to definitively determine the source country of an echidna and explore the use of non-invasive sampling techniques. Here we use non-invasively sampled echidna quills and demonstrate the extraction of mitochondrial DNA and amplification of a region of the mitochondrial genome. Phylogenetically informative markers for analysis of a 322bp segment of the D-loop region were developed, and subsequently validated, using animals with known source locations allowing us to reliably distinguish between echidnas from New Guinea, and Australia. This research presents the first validated forensic protocols for short beaked echidnas and will be an integral tool in understanding the movement of animals in this emerging trade.

Unexplained vision loss following removal of epiretinal membrane.

PURPOSE: To report unexplained severe central vision loss accompanied by a dense central scotoma as an uncommon complication following epiretinal membrane removal. METHODS: Retrospective, multicentred, case series. RESULTS: Six patients underwent uncomplicated vitrectomy surgery between 2000 and 2007 at four separate retina practices for removal of an epiretinal membrane. Preoperative vision ranged from 20/60 to 20/100, with a median of 20/70. On the first day postoperatively, all patients noted decreased vision ranging from counting fingers to light perception and were found to have a dense central scotoma. Posterior segment examination revealed a white, oedematous macula in all affected eyes. Vision improved minimally during the follow-up period, which ranged from 2 months to 5 years. The final vision ranged from 20/200 to hand movements. No anatomic or physiologic cause for the decreased vision and central scotoma was identified. CONCLUSIONS: While uncommon, severe, permanent, central vision loss accompanied by a dense central scotoma can occur following epiretinal membrane removal and should be considered when assessing the risks and benefits of such surgery.

Genetic control of the honey bee (Apis mellifera) dance language: segregating dance forms in a backcrossed colony.

We studied the genetic control of the dance dialects that exist in the different subspecies of honey bees (Apis mellifera) by observing the variation in dance form observed in a backcross between two lines that showed widely different dance dialects. To do this we generated the reciprocal of the cross performed by Rinderer and Beaman (1995), thus producing phenotypic segregation of dance forms within a single colony rather than between colonies. Our results are consistent with Rinderer and Beaman (1995) in that inheritance of the transition point from round dancing --> waggle dancing is consistent with control by a single locus with more than one allele. That is, we found one dance type to be dominant in the F(1), and observed a 1:1 segregation of dance in a backcross involving the F(1) and the recessive parent. However, we found some minor differences in dance dialect inheritance, with the most significant being an apparent reversal of dominance between our cross (for us "black" is the dominant dialect) and that of Rinderer and Beaman (1995) (they report "yellow" to be the dominant dialect). We also found that our black bees do not perform a distinct sickle dance, whereas the black bees used by Rinderer and Beaman (1995) did perform such a dance. However, our difference in dominance need not contradict the results of Rinderer and Beaman (1995), as there is no evidence that body color and dominance for dance dialect are linked.

Massive suprachoroidal hemorrhage during pars plana vitrectomy associated with Valsalva maneuver.

PURPOSE: To report the intraoperative occurrence of massive intraocular suprachoroidal hemorrhage associated with Valsalva maneuver. METHODS: Retrospective, multicenter study of patients who developed massive choroidal hemorrhage associated with Valsalva maneuver during vitrectomy. RESULTS: Massive intraoperative suprachoroidal hemorrhage in seven patients (seven eyes) involved three men and four women with a median age of 52 years (range, 26 to 82 years). General anesthesia was used in six of seven cases. Coughing or "bucking" on the endotracheal tube during general anesthesia or severe coughing during the one vitrectomy performed under local anesthesia was associated with massive suprachoroidal hemorrhage. In five of seven eyes, this occurred near the end of surgery, after air-fluid exchange but before sclerotomy closure. Scleral plugs were immediately placed, and sclerotomy closure was performed exigently. Immediate posterior sclerotomy was performed on five of seven eyes; an additional patient underwent posterior sclerotomy postoperatively. After median follow-up of 18 months (range, 3 to 36 months), final visual acuity was no light perception in four eyes, light perception in one eye, 20/250 in one eye, and 20/20 in one eye. Four eyes became phthisical. CONCLUSIONS: Valsalva maneuver during pars plana vitrectomy may result in massive suprachoroidal hemorrhage with disastrous visual consequences. Precautionary measures to prevent coughing or "bucking" on the endotracheal tube during general anesthesia, or a prolonged episode of coughing during local anesthesia, may prevent this potentially devastating complication.

Error detection and measurement in glucose monitors.

In a quality review of glucose monitors, we measured the inaccuracy and imprecision of 26 systems. In each case, measurements on at least 50 capillary specimens from diabetic patients were compared with results from capillary blood that had been deproteinized and assayed with hexokinase. We also tested the monitors with commercial control solutions. In patients' specimens having a mean blood glucose concentration of about 9 mmol/l, the bias of the 26 monitors ranged from -5.1 to +20.1% (median=+7.5%). Imprecision of the monitors with blood specimens gave coefficients of variation (CV) ranging from 4.5% to 22.8% (median=8.7%) at the mean glucose concentration. A control solution for the monitors gave a glucose concentration of 7.6-13.6 mmol /l (median=9.2 mmol/l) with CV that varied from 1.7 to 19.8% (median=4.7%). While the means and CV's of the control were significantly correlated with bias and imprecision of the blood specimens, much of the variance remained unexplained (for bias, r(2)=0.17; for imprecision, r(2)=0.43). We conclude that a common basis for calibration could remove a significant component of variation and that control solutions may give a false impression of analytical performance.

Traumatic macular hole: observations, pathogenesis, and results of vitrectomy surgery.

PURPOSE: To review our experience with vitrectomy surgery techniques for the treatment of traumatic macular holes and the biomicroscopic and surgical findings. DESIGN: Retrospective noncomparative, multicenter, case series. PARTICIPANTS AND INTERVENTION: Twenty-five patients with traumatic macular hole underwent surgical repair. INTERVENTION: Vitrectomy with membrane peeling and gas injection followed by prone positioning for 7 to 14 days. MAIN OUTCOME MEASURES: Postoperative evaluation included visual acuity testing, closure of the macular hole, and ocular complications. RESULTS: The macular hole was successfully closed in 24 of 25 cases (96%). The visual acuity improved two or more lines in 21 (84%) cases, and 16 (64%) achieved 20/50 or better vision. CONCLUSIONS: Vitrectomy surgery can successfully close macular holes associated with trauma and improve vision.

Sympathetic ophthalmia associated with pars plana vitrectomy without antecedent penetrating trauma.

PURPOSE: To evaluate, describe, and categorize the clinical presentation, clinical course, histopathology, and response to therapy in patients without a history of penetrating ocular trauma who developed sympathetic ophthalmia following pars plana vitrectomy. METHODS: The records of patients without a history of trauma who underwent pars plana vitrectomy and developed sympathetic ophthalmia were retrospectively reviewed. Cases were analyzed with respect to clinical presentation, fluorescein angiographic findings, anatomic and visual outcomes, histopathology, and response to therapy. RESULTS: Eight eyes were identified. The median age at presentation was 55 years, with a range of 14 to 62 years. The time from vitrectomy to diagnosis of sympathetic ophthalmia ranged from 2 months to greater than 2 years, with a median of 7 months. Six of eight patients (75%) presented with anterior chamber reaction. All eight patients presented with a vitreous inflammatory response. The optic nerve was inflamed clinically or angiographically in four of eight cases (50%). Small yellow-white sub-retinal pigment epithelial deposits were present in four of eight cases (50%). Two eyes had lesions characterized as multifocal choroiditis. One eye had larger yellow placoid-like lesions. One eye presented with vitritis but no retinal lesions. Subretinal choroidal neovascularization was noted in the inciting eye of one patient. Vision improved in the sympathizing eye with immunosuppressive therapy in five of eight cases (62.5%). CONCLUSIONS: Sympathetic ophthalmia can be seen following pars plana vitrectomy in patients without penetrating injuries or a history of trauma. Indeed, it may be seen after successful vitrectomy for retinal detachment. Diverse clinical presentations are possible, and persistent or atypical uveitis following vitrectomy should alert the surgeon to the development of sympathetic ophthalmia.

Soccer ball-related retinal injuries: a report of 13 cases.

PURPOSE: To describe the clinical characteristics and management of retinal injuries caused by soccer ball impact as well as the mechanism of injury, prognostic features, risk factors, and possible prevention strategies. METHODS: Thirteen cases of soccer ball injuries from retina referral practices were retrospectively reviewed, with attention to the mechanism of associated ocular complications and the anatomic and visual outcomes. RESULTS: Soccer ball injuries occurred in both male and female patients (9 male, 4 female) with ages ranging from 8 to 21 years (median 14 years). These patients were observed from 0 to 64 months (median follow-up, 8 months). Four patients had traumatic macular holes, two eyes had retinal detachment associated with retinal dialysis, two had retinal tears associated with hemorrhage, one had a choroidal rupture, and one had only vitreous hemorrhage and Berlin's edema. Although six eyes had some degree of traumatic retinal pigment epitheliopathy, it was the primary diagnosis in only three. Visual acuity at presentation ranged from 20/20 to count fingers, with 7/13 (54%) having 20/200 or worse vision. Seven eyes underwent surgical procedures; the remainder were observed. Final visions ranged from 20/20 to count fingers, with 3/13 (23%) having 20/200 or worse vision. Six eyes (46%) improved by two or more lines by the last follow-up. CONCLUSION: Soccer ball-related ocular injuries disproportionately affect young players, are more frequent in females than previously reported, and have more severe visual consequences than previously recognized. Injury prevention strategies to minimize contact between the eye and the soccer ball may reduce the incidence and severity of eye injuries.

Vitrectomy update for macular traction in ocular toxocariasis.

PURPOSE: To study the results of modern vitrectomy in traction and combined traction-rhegmatogenous retinal detachment involving the macula in cases of ocular toxocariasis. METHODS: This was a cohort study of patients seen in different institutions in the United States. Ten eyes of 10 patients were studied. Vitrectomy was performed in all eyes, combined with membrane removal, scleral buckle, fluid-gas exchange, silicone oil, or lensectomy in certain cases. The anatomic and visual results of surgery were reviewed. RESULTS: Ten eyes from 10 patients ranging in age from 2 to 33 years (median, 6 years) were reviewed. Follow-up ranged from 3 months to 8 years (median, 2 years). All eyes achieved macular attachment following surgery; vision improved in 5 (50%) eyes, and was unchanged in 5 (50%). Histologic specimens from six eyes were reviewed, and revealed combinations of fibrous tissue, eosinophils, plasma cells, lymphocytes, and giant cells. One specimen revealed an encysted Toxocara canis organism. CONCLUSION: Inflammation created in response to Toxocara larvae may lead to traction retinal detachment of the macula. Vitreoretinal surgery has a good chance of reattaching the macula and improving vision.

Serum troponins T and I after elective cardioversion.

AIMS: To describe the pattern of release of five myocardial proteins after elective cardioversion. METHODS AND RESULTS: We measured serum levels of the myocardial proteins creatine kinase, creatine kinase MB mass, myoglobin, troponin T and troponin I serially from baseline to 24 h after 72 elective cardioversion attempts. The total energy used for attempted cardioversion was 408+/-318 J (range 50 to 1280 J). Maximal creatine kinase levels (median 232 IU x l(-1), interquartile range 91 to 1152 IU x l(-1)) occurred at 24 h and correlated with the total energy delivered (r=0.75, P<0.0001). The peak creatine kinase MB mass levels exceeded the discrimination level for myocardial injury (>/=5 microg x l(-1)) in seven patients (10%). The peak myoglobin levels were elevated (>85 microg x l(-1)) in 40 patients (56%) and correlated with the peak creatine kinase levels (r=0.83, P<0.0001). Troponin T reached the discrimination level (0.10 microg x l(-1)) in one patient with a serum creatinine level of 0.16 mmol x l(-1)and severe left ventricular impairment. Twelve patients had baseline troponin I levels above our prespecified discrimination level of 0.4 microg x l(-1)(range 0.4 to 3.1 microg x l(-1)), which did not increase after cardioversion. In two patients the levels rose from <0.4 microg x l(-1) to 0.5 microg x l(-1) and 0.6 microg x l(-1) respectively. CONCLUSIONS: Troponin T levels do not rise after elective cardioversion. The minor increases in troponin I may reflect our choice of discrimination level. Cardiac troponins are useful in determining whether arrhythmias requiring emergency cardioversion are primary or secondary to myocardial infarction.

Analytical error of home glucose monitors: a comparison of 18 systems.

In a quality review of 18 home blood glucose monitors, we measured the imprecision and incidence of significant error of 12 colorimetric and six amperometric systems by using capillary blood specimens from patients attending diabetes clinics. Imprecision at the mean glucose concentration found in the respective blood specimens (about 9 mmol/L) gave coefficients of variation (CV) ranging from 5.2 to 22.8%. Eight monitors including five of amperometric design had a CV of less than 10%. The incidence of significant error (defined as the proportion of specimens differing in value by more than 15% from a reference hexokinase assay of glucose in capillary blood) varied from 6 to 76%. Among the eight monitors identified as being most precise, the majority produced results that differed markedly from the reference assay, underlining the need for a common approach to calibration of home glucose monitors.

Phlebotomine sand fly (Diptera: Psychodidae) seasonal distribution and infection rates in a defined focus of Leishmania tropica.

A two-year study was conducted of phlebotomine sand fly fauna in a defined focus of Leishmania tropica. A total of 17,947 sand flies representing 10 species were collected from the location. Phlebotomus guggisbergi, a vector of L. tropica in Kenya, was the most prevalent species through the entire period, representing about 80% of the total catch. There was marked seasonal fluctuation in the populations of the three most common species, with highest population levels reached in December and lowest levels reached in July and August. Leishmania-like infections were encountered in 489 P. guggisbergi. No flagellate infections were observed in any other species of sand fly. Although infected P. guggisbergi were collected during each month of the year, the percent parous infected flies was highest (27.5%) during the November through January time period. These data show that the greatest risk of transmission to humans at this focus occurs during December, when the vector is prevalent and infections are common.

Rash, fever, and chills after intravenous fluorescein angiography.

PURPOSE: To report a previously unreported complication associated with intravenous injection of fluorescein dye. METHOD: Case report. A 75-year-old man developed a unique complication after intravenous injection of fluorescein dye for angiography. RESULTS: Two hours after receiving an intravenous injection of fluorescein for angiography, the patient developed a fever, rash, and chills. Admission to a hospital and careful systemic evaluation determined that this reaction was a noninfectious allergic response to intravenous fluorescein dye injection. CONCLUSION: A delayed allergic response to intravenous fluorescein dye injection can occur.

Crystalline retinopathy associated with chronic retinal detachment.

OBJECTIVE: To describe the presence of crystalline opacities located at the level of the inner retina in patients with chronic retinal detachment. METHODS: We reviewed the clinical records, fundus photographs, and fluorescein angiograms of patients with superficial retinal crystals in the presence of a chronic retinal detachment. RESULTS: Eleven eyes in 11 patients with chronic retinal detachment were found to have these peculiar crystalline opacities on the inner retinal surface. In 5 patients, the crystalline opacities were noted on initial assessment prior to surgery and persisted without change in appearance or number after surgical repair. In 6 eyes, the crystals were not appreciated until after surgical repair of the retinal detachment. The crystals appeared similar in all 11 eyes, were highly refractile, and were located in the posterior pole. Eight of the eyes had retinal detachment associated with retinal dialysis and 6 of these had a history of trauma. There was a definite history of vitreous hemorrhage in 2 eyes. The crystals did not seem to be associated with any visual deficit. CONCLUSIONS: Chronic retinal detachment can be associated with crystals on the inner retinal surface. The cause and composition of these crystals are unknown. They seem to be visually inconsequential and unchanging.