Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way.

The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.

Observer variation in the evaluation and classification of severe central tarsal bone fractures in racing Greyhounds.

OBJECTIVES: To determine observer agreement on radiographic evaluation of central tarsal bone (CTB) fractures and compare this with evaluation of the same fractures using computed tomography (CT). METHODS: Radiographs and CT scans were obtained of the right tarsi from limbs of Greyhounds euthanatized after sustaining severe CTB fracture during racing. Four observers described and classified each fracture. Inter- and intra-observer agreements were calculated. RESULTS: Inter-observer agreement was higher for assessment of fractures using CT. Several fractures assessed by radiography were misclassified as a less severe type. Intra-observer agreement for assessment and classification of CTB fractures via radiography versus CT was variable. Overall agreement among all four observers was higher for CT than radiography. Additionally, when identifying fractures of the adjacent tarsal bones, observer agreement was higher for CT than radiography. CLINICAL SIGNIFICANCE: Computed tomography improved observer ability to correctly evaluate CTB fracture and detect the degree of displacement and extent of any comminution. Identification of fractures of adjacent tarsal bones was also improved when tarsi were assessed using CT. These data suggest that treatment decisions based solely on radiographic assessment of CTB fractures may not produce the expected outcome.

Repair of Y-T humeral fractures in the dog using paired 'String of Pearls' locking plates.

OBJECTIVES: To describe a technique for treating Y-T humeral fractures using paired string of pearls (SOP) plates and to review the outcome in 13 cases. METHODS: A series of 13 consecutive Y-T humeral fractures, otherwise known as distal humeral dicondylar fractures, were treated according to a surgical protocol which involved combined medial and lateral surgical approaches, accurate reduction and fixation of the condylar fracture with a single transcondylar lag screw, and then re-alignment and fixation of the diaphyseal fracture using two SOP plates and screws. RESULTS: Functional outcome was recorded as excellent in 10 dogs, good in two and poor in one. Six of the 13 patients were working dogs and of these, five returned to pre-injury levels of activity, including work. Complications requiring additional surgery were seen in four of the 13 cases, and three of these cases had a sub-optimal functional outcome. CLINICAL SIGNIFICANCE: The results following repair of Y-T fractures using SOP locking plates, placed via combined medial and lateral incisions, compared favourably with those reported for other techniques.

The effect of bending and twisting on the stiffness and strength of the 3.5 SOP implant.

Locking plates are becoming increasingly popular in veterinary orthopaedics. The SOP is a novel locking plate system, which can be contoured with 6 degrees of freedom and which utilises standard bone screws. The purpose of this work was to investigate the mechanical consequences of contouring the 3.5 SOP plate to support the formulation of clinical guidelines. The implants were loaded in four point bending using an industry standard protocol. The uncontoured SOP was found to be significantly stiffer and stronger than the uncontoured 3.5 DCP. Bending, and to a lesser extent, twisting, diminished the SOP's stiffness and strength but the contoured SOP remained at least as stiff and strong as the untouched DCP.

Meticillin-resistant Staphylococcus aureus in a veterinary orthopaedic referral hospital: staff nasal colonisation and incidence of clinical cases.

OBJECTIVES: To evaluate staff nasal colonisation with meticillin-resistant Staphylococcus aureus in a veterinary orthopaedic referral hospital, and its effect on the occurrence of meticillin-resistant Staphylococcus aureus-associated postoperative wound complications in orthopaedic and spinal surgical patients. METHODS: Nasal bacterial swabs were collected from veterinary staff and environmental surfaces swabbed at six monthly intervals for meticillin-resistant Staphylococcus aureus monitoring over an 18 month period. The incidence of meticillin-resistant Staphylococcus aureus-associated postoperative wound complications of two veterinary orthopaedic surgeons was reviewed for a period when one was positive for nasal meticillin-resistant Staphylococcus aureus. RESULTS: Meticillin-resistant Staphylococcus aureus was isolated from a maximum of two out of 10 staff on each occasion. The persistently infected clinician was primary surgeon in 180 cases, of which four developed meticillin-resistant Staphylococcus aureus-associated wound complications. None of 141 operations led by the other surgeon developed meticillin-resistant Staphylococcus aureus-associated complications. This difference is not statistically significant (P=0.0974). The 95 per cent confidence interval for this odds ratio was 0.83 to 44.0. Meticillin-resistant Staphylococcus aureus resistance patterns of the human nasal isolates and three of four wound-associated isolates were similar. CLINICAL SIGNIFICANCE: Veterinary workers are at increased risk for meticillin-resistant Staphylococcus aureus colonisation, so it is likely that many veterinary patients are treated by meticillin-resistant Staphylococcus aureus-positive staff. Nasal colonisation of veterinary surgeons with meticillin-resistant Staphylococcus aureus appears to present only a small risk to their patients when appropriate infection control procedures are followed.

A mechanical evaluation of pre-tapped and self-tapped screws in small bones.

The purpose of this study was to compare the holding powers of 2.7 mm pre-tapped and self-tapped screws placed closely together and tightened in small bones. Pairs of metatarsals were collected from healthy, skeletally mature Greyhounds and part of a 2.7 mm dynamic compression plate was fixed to the dorsal surface of each bone using three 2.7 mm screws. Identical screws were used throughout but only one of each pair of bones had threads pre-cut using a tap prior to insertion. All of the screws were tightened before the constructs were mounted in a materials testing machine and the centrally placed screw was loaded incrementally until failure. Load-deformation curves were plotted and yield point, ultimate load to failure, stiffness and energy prior to yield point were measured. Mean values were recorded for each parameter and Student's T-test was used to test the null hypothesis that there is no difference in holding power between pre-tapped and self-tapped screws. Significant mechanical differences were not found between pre-tapped and self-tapped screws placed closely together and tightened into small bones. Self-tapped screws can be considered for use in small animal surgery even when multiple screws are to be placed closely together in relatively small pieces of bone.

Radiographic assessment of the skeletons of Dolly and other clones finds no abnormal osteoarthritis.

Our recent report detailing the health status of cloned sheep concluded that the animals had aged normally. This is in stark contrast to reports on Dolly (first animal cloned from adult cells) whose diagnoses of osteoarthritis (OA) at 5½ years of age led to considerable scientific concern and media debate over the possibility of early-onset age-related diseases in cloned animals. Our study included four 8-year old ewes derived from the cell line that gave rise to Dolly, yet none of our aged sheep showed clinical signs of OA, and they had radiographic evidence of only mild or, in one case, moderate OA. Given that the only formal record of OA in Dolly is a brief mention of a single joint in a conference abstract, this led us to question whether the original concerns about Dolly's OA were justified. As none of the original clinical or radiographic records were preserved, we undertook radiographic examination of the skeletons of Dolly and her contemporary clones. We report a prevalence and distribution of radiographic-OA similar to that observed in naturally conceived sheep, and our healthy aged cloned sheep. We conclude that the original concerns that cloning had caused early-onset OA in Dolly were unfounded.

Treatment of inherently unstable open or infected fractures by open wound management and external skeletal fixation.

OBJECTIVES: To assess the use of external skeletal fixation with open wound management for the treatment of inherently unstable open or infected fractures in dogs. METHODS: A retrospective review of 10 cases. RESULTS: Fracture stabilisation and wound management required only a single anaesthetic, and despite the challenging nature of these injuries, the final outcome was acceptable or good in every case. However, minor complications associated with the fixator pins were quite common, and two dogs developed complications which required additional surgery. CLINICAL SIGNIFICANCE: Open management of wounds, even when bone was exposed, proved to be an effective technique, and external skeletal fixators were usually effective at maintaining stability throughout an inevitably extended fracture healing period.

Systematic review of the prevalence, risk factors, diagnosis and management of meniscal injury in dogs: Part 1. [corrected].

OBJECTIVE: To systematically evaluate the evidence reporting the frequency and risk factors of meniscal injury in dogs with cranial cruciate ligament failure. STUDY DESIGN: Systematic literature review. MATERIALS AND METHODS: Research questions were defined. An electronic database search of PubMed and CAB Abstracts was performed during November 2013. Data were extracted for study participants, design, intervention, outcome measures and results. Studies were evaluated using a validated instrument for assessing methodological quality and assigned a quality index score. A level of evidence was then assigned to each study. RESULTS: Sixty-two studies were identified. The median quality index score was 14 out of a possible 26. Twenty-four studies were prospective case series, 37 retrospective case series and 1 animal research study. There were no class I or class II studies, 24 class III studies and 38 class IV studies. CLINICAL SIGNIFICANCE: Despite a large number of publications the quality of evidence was generally low. No one study or combination of studies provided high quality evidence to establish the true frequency or risk factors for meniscal injury in dogs with cranial cruciate ligament failure.

Systematic review of the prevalence, risk factors, diagnosis and management of meniscal injury in dogs: Part 2.

OBJECTIVE: To systematically evaluate the evidence reporting the diagnosis and management of meniscal injury in dogs with cranial cruciate ligament failure. STUDY DESIGN: Systematic literature review. MATERIALS AND METHODS: Research questions relating to the accuracy of diagnostic techniques for meniscal injury and the effects of meniscal treatment were defined. An electronic database search of PubMed and CAB Abstracts was performed during March 2015. Data were extracted for study participants, design, intervention, outcome measures and results. Studies were evaluated using a validated instrument for assessing methodological quality and assigned a Quality Index score. A level of evidence was then assigned to each study. RESULTS: Eighty-nine studies were identified. The median Quality Index score was 14 out of a possible 26. Twenty-seven studies were prospective case series, 31 retrospective case series, 16 animal research and 15 cadaveric studies. There were no class I or class II studies, 27 class III and 62 class IV studies. CONCLUSIONS: Despite a large number of publications the quality of evidence was generally low. No one study or combination of studies provided high quality evidence to support one diagnostic or surgical intervention over another for meniscal injuries in dogs with cranial cruciate ligament failure.

A study of patient acceptance of double-contrast barium enema and colonoscopy. Which procedure is preferred by patients?

To our knowledge, no previous study has addressed the question of which method of evaluation of the lower gastrointestinal tract is preferred by patients, air-contrast barium enema or colonoscopy. Over a four-month period, we asked 189 consecutive patients who had undergone colonoscopy to express their preference for either air-contrast barium enema or colonoscopy. A clear preference for colonoscopy was expressed by our patients in terms of comfort and polyp detection despite higher cost. Time lost from work and post-procedure constipation were significantly less for colonoscopy than for barium enema. These factors should be considered in the evaluation of suspected lower gastrointestinal tract disease.

Mechanical comparison of monofilament nylon leader and orthopaedic wire for median sternotomy closure.

OBJECTIVES: To compare the mechanical properties of monofilament nylon leader and orthopaedic wire for median sternotomy closure in the dog. MATERIALS AND METHODS: Median sternotomy was performed in 14 canine cadaver sternums with the manubrium intact. The sternotomy was closed with either 80 lb monofilament nylon leader or 20G orthopaedic stainless steel wire in a peristernal figure of 8 pattern. Constructs were loaded in a servohydraulic material testing machine. Load at yield, maximum load, stiffness, displacement and mode of failure were compared between constructs subjected to a single cycle load to failure. RESULTS: No significant differences were found in load at yield, maximum load, stiffness or displacement between the monofilament nylon leader and the stainless steel wire constructs. No implant failure was evident in the stainless steel wire constructs. Four of the monofilament nylon leader constructs failed by pulling of the nylon through the crimp. CLINICAL SIGNIFICANCE: Monofilament nylon leader is mechanically comparable to stainless steel wire and potentially a suitable alternative for closure of median sternotomy in the dog.

Effect of bending direction on the mechanical behaviour of 3.5 mm String-of-Pearls and Limited Contact Dynamic Compression Plate constructs.

OBJECTIVE: To compare the bending properties of String-of-Pearls® (SOP) and Limited Contact Dynamic Compression Plate® (LC-DCP) constructs in orthogonal bending directions. METHODS: 3.5 mm SOP and LC-DCP plates were fixed to a bone model simulating a comminuted tibial fracture. Specimens were non-destructively tested in both mediolateral and craniocaudal bending for 10 cycles. Bending stiffness and total angular deformation were compared using parametric analyses (p <0.05). RESULTS: For both constructs, stiffness was significantly less when bending moments were applied against the thickness of the plates (mediolateral bending) than against the width (craniocaudal bending). When compared to the mediolateral plane, bending constructs in the craniocaudal plane resulted in a 49% (SOP group) and 370% (LC-DCP group) increase in stiffness (p <0.001). Mediolateral bending stiffness was significantly greater in the SOP than the LC-DCP constructs. Conversely, in craniocaudal bending, SOP constructs stiffness was significantly less than that of the LC-DCP constructs. The differences between the two constructs in total angular deformation had an identical pattern of significance. CLINICAL SIGNIFICANCE: This study found that SOP showed less variability between the orthogonal bending directions than LC-DCP in a comminuted fracture model, and also described the bi-planar bending behaviour of both constructs. Although not exhibiting identical bending properties in both planes, SOP constructs had a more homogenous bending behaviour in orthogonal loading directions. The difference between the SOP with a circular cross sectional shape compared to the rectangular shape of standard plates is probably responsible for this difference.

Reactivity of CO17-1A and B72.3 in benign and malignant pancreatic diseases.

The immunoreactivity of two monoclonal antibodies, CO17-1A (recognizing 17-1A antigen) and B72.3 (recognizing TAG-72), was examined in pancreatic tissues from individuals without pancreatic disease and from those with benign and malignant pancreatic disease. 17-1A antigen was found in all cells in the normal tissue, whereas TAG-72 was present in the duct cells in only one case. Both antigens were present in benign diseases; however, in some cells and in some conditions, TAG-72 was significantly less common (P less than .01 to .001) than 17-1A antigen. In pancreatic cancer, 17-1A antigen was present in 87% of cases and TAG-72 antigen was present in 92% of cases. The results indicate that B72.3 is more specific to pancreatic cancer than C017-1A.

Disseminated Trichosporon beigelii infection after orthotopic liver transplantation.

A 25-year-old male, who received an orthotopic liver transplant for fulminant hepatic failure resulting from hepatitis B, had disseminated Trichosporon beigelii infection develop. Of the 55 cases of disseminated T. beigelii that have been reported in the English-language medical literature, most have occurred in patients who were both neutropenic and had compromised cell-mediated immunity. Mortality has ranged from 60 to 78%. Outcome appears to depend significantly on leukocyte recovery. Histologically, Trichosporon can be confused with Candida; however, recognition of the arthroconidia and pleomorphic hyphae and pseudohyphae of Trichosporon should allow their differentiation.

Acute myelogenous leukemia with eosinophilic differentiation and trisomy-1.

A 50-year-old woman presented with anemia and eosinophilia. Her bone marrow biopsy, peripheral blood, and clinical features were consistent with a diagnosis of an evolving acute myelogenous leukemia. Striking dysplastic eosinophilic differentiation associated with trisomy-1 was evident, and eosinophil granule major basic protein was detected in involved tissue. Trisomy-1 has not been previously reported in association with acute myelogenous leukemia showing eosinophilic differentiation. Intensive cytotoxic chemotherapy produced a short-lived clinical and cytogenetic remission. At autopsy multiple tumor nodules composed of dysplastic eosinophil precursors and myeloblasts were evident in multiple organs.

Anomalous right coronary artery origin in otherwise unexplained infant death.

Anomalous origin of the right coronary artery from the left sinus of Valsalva has only recently become recognized as a cause of sudden death in neonates, infants, and young children. The mechanism of death in these cases may be decreased myocardial perfusion by the anomalous vessel due to a combination of factors. Tangential takeoff of the vessel with resultant slitlike ostium and its initial investment in the aortic adventitia with diastolic entrapment and compression are both thought to be at play. Since 1983, three infants with this anomaly and associated sudden death have been described. We describe a fourth case and offer an assessment of the overall frequency of this potentially fatal abnormality.

Bronchoalveolar lavage in the assessment of pulmonary Hodgkin's disease.

Abnormal chest radiographs in patients with Hodgkin's disease are occasionally due to pulmonary Hodgkin's disease. The fluids recovered from bronchoalveolar lavages (BALs) from 50 patients prior to autologous bone marrow transplantation for advanced Hodgkin's disease were examined. Abnormal chest roentgenograms were present in 24 patients (48%); 4 (17%) of these had Reed-Sternberg cells or their mononucleated variants in the lavage fluid and an alveolar lymphocytosis averaging 31.4% (normal: 11.5%). The lymphocytes were small and monotonous. Of the 20 patients with abnormal chest roentgenograms but no Reed-Sternberg cells in the lavage fluid, the lymphocyte count was 10.88%, with only 3 patients exceeding 17%. Two patients with normal chest roentgenograms had Reed-Sternberg-like cells in their lavage fluids and averaged 23% lymphocytes in their lavage differential count. Eosinophils averaged 1% or less of the lavage differential and were not predictive of pulmonary Hodgkin's disease. This experience suggests that pulmonary Hodgkin's disease can be diagnosed by BAL. Reed-Sternberg cells and their mononucleated variants can be recognized by their characteristic cytomorphologic features, although care must be taken not to misinterpret reactive binucleated macrophages as neoplastic cells. In patients with Hodgkin's disease, Reed-Sternberg cells should be sought when an alveolar lymphocytosis is present.

Detection of Candida antigen in bronchoalveolar lavage fluid.

While bronchoalveolar lavage is frequently performed to evaluate immunocompromised hosts for infection, the significance of rare yeasts found on the cytologic examination of lavage fluid is unclear. This study used the latex agglutination method to test lavage fluids for Candida antigen to assess its usefulness in distinguishing Candida pneumonia from Candida colonization of the respiratory tract or oral contamination of the lavage specimen. Ninety-seven specimens from 87 patients were categorized on the basis of historical, microbiologic, cytologic and serologic data. Bronchoalveolar lavage fluids were positive for Candida antigen in 0 of 20 specimens from normal controls, 0 of 14 specimens from patient controls, 5 (36%) of 14 specimens from patients with Pneumocystis carinii pneumonia, 0 of 5 specimens from patients with gastrointestinal candidiasis, 0 of 9 specimens contaminated by oral-derived yeasts, 2 (10%) of 19 specimens from patients with probable Candida colonization and 15 (94%) of 16 specimens from patients with clinical and laboratory evidence of Candida pneumonia. We conclude that this test assists in the differentiation of Candida pneumonia from other situations in which yeasts are recovered by bronchoalveolar lavage.

Infiltration and redistribution of LNAPL into unsaturated layered porous media.

Enhanced understanding of light non-aqueous phase liquid (LNAPL) infiltration into heterogeneous porous media is important for the effective design of remediation strategies. We used a 2-D experimental facility that allows for visual observation of LNAPL contours in order to study LNAPL redistribution in a layered porous medium. The layers are situated in the unsaturated zone near the watertable and they are inclined to be able to observe the effect of discontinuities in capillary forces and relative permeabilities. Two experiments were performed. The first experiment consisted of LNAPL infiltration into a fine sand matrix with a coarse sand layer, and the second experiment consisted of a coarse sand matrix and a fine sand layer. The numerical multi-phase flow model STOMP was validated with regard to the experimental results. This model is able to adequately reproduce the experimental LNAPL contours. Numerical sensitivity analysis was also performed. The capillarity contrast between sands was found to be the main controlling factor determining the final LNAPL distribution.