Exploring diastolic pressure ratio to fractional flow reserve discordance and a hypothesis on tailoring diastolic pressure ratio cut-off values to improve diagnostic accuracy in the mid- and distal-LAD.

Previous studies have identified a higher rate of discordance between non-hyperaemic pressure ratios and FFR in the LAD when compared to the other two coronary arteries. We hypothesised that in keeping with recently published data, we would identify a higher discordance rate between diastolic pressure ratio (DPR) and FFR in the LAD compared to the RCA or LCx. In our study, 12.7% of LAD lesions had discordant results compared with 2.4% of non-LAD lesions. This represents a statistically significant increased rate of discordance in LAD lesions compared to non-LAD lesions (p = 0.04986). Note was made of a tendency for non-proximal LAD lesions to be associated with false-positive DPR results in the borderline range (0.88 and 0.89). In a speculative, hypothesis generating post-hoc analysis, we found an improved diagnostic accuracy of DPR when the cut-off value for a positive DPR in the non-proximal LAD was changed to ≤0.87. It is fathomable that improvements in the diagnostic accuracy of DPR for FFR may be improved by tailoring DPR cut-offs to the location of the lesion assessed.

Light scattering and random lasing in aqueous suspensions of hexagonal boron nitride nanoflakes.

Liquid phase exfoliation allows large scale production of 2D materials in solution. The particles are highly anisotropic and strongly scatter light. While spherical particles can be accurately and precisely described by a single parameter-the radius, 2D nanoflakes, however, cannot be so easily described. We investigate light scattering in aqueous solutions of 2D hexagonal boron nitride nanoflakes in the single and multiple scattering regimes. In the single scattering regime, the anisotropic 2D materials show a much stronger depolarization of light when compared to spherical particles of similar size. In the multiple scattering regime, the scattering as a function of optical path for hexagonal boron nitride nanoflakes of a given lateral length was found to be qualitatively equivalent to scattering from spheres with the same diameter. We also report the presence of random lasing in high concentration suspensions of aqueous h-BN mixed with Rhodamine B dye. The h-BN works as a scattering agent and Rhodamine B as a gain medium for the process. We observed random lasing at 587 nm with a threshold energy of 0.8 mJ.

Nurse Triage in an Irish Out-of-hours General Practice Co-Operative.

Specially trained triage nurses play a crucial role in the operation of out-of-hours GP co-operatives. This study aimed to establish the proportion of all patient contacts with the out-of-hours GP co-operative based in the Mid-West of Ireland (Shannondoc), which were managed by triage nurses. A retrospective, descriptive analysis was conducted on the database of contacts to the Shannondoc urgent, out-of-hours primary care co-operative. Of the 110,039 contacts to the service in 2013, 19,147 (17.4%) were classified as being managed by nurses and 14.2% were managed by nurse telephone triage alone. Twenty-four percent of the 19,147 calls managed by nurses involved children under six years. Triage nurses play an important role in administering safe medical advice over the phone. This has implications for the training of triage nurses and the future planning of urgent out-of-hours primary care services.

The Global Genome Biodiversity Network (GGBN) Data Standard specification.

Genomic samples of non-model organisms are becoming increasingly important in a broad range of studies from developmental biology, biodiversity analyses, to conservation. Genomic sample definition, description, quality, voucher information and metadata all need to be digitized and disseminated across scientific communities. This information needs to be concise and consistent in today's ever-increasing bioinformatic era, for complementary data aggregators to easily map databases to one another. In order to facilitate exchange of information on genomic samples and their derived data, the Global Genome Biodiversity Network (GGBN) Data Standard is intended to provide a platform based on a documented agreement to promote the efficient sharing and usage of genomic sample material and associated specimen information in a consistent way. The new data standard presented here build upon existing standards commonly used within the community extending them with the capability to exchange data on tissue, environmental and DNA sample as well as sequences. The GGBN Data Standard will reveal and democratize the hidden contents of biodiversity biobanks, for the convenience of everyone in the wider biobanking community. Technical tools exist for data providers to easily map their databases to the standard.Database URL: http://terms.tdwg.org/wiki/GGBN_Data_Standard.

Osteosarcoma: A rare cause of painful enlargement of the hallux.

Malignant osseous and soft-tissue tumors of the foot are rare. We report a case of osteosarcoma in the proximal phalanx of the hallux in a 45-year-old man. In patients with foot-related symptoms, a high index of suspicion for pedal osteosarcoma is required. Delayed or inappropriate diagnosis may compromise limb-sparing surgery and survivorship.

The use of uncemented extensively porous-coated femoral components in the management of Vancouver B2 and B3 periprosthetic femoral fractures.

We assessed the outcome of patients with Vancouver type B2 and B3 periprosthetic fractures treated with femoral revision using an uncemented extensively porous-coated implant. A retrospective clinical and radiographic assessment of 22 patients with a mean follow-up of 33.7 months was performed. The mean time from the index procedure to fracture was 10.8 years. There were 17 patients with a satisfactory result. Complications in four patients included subsidence in two, deep sepsis in one, and delayed union in one. Concomitant acetabular revision was required in 19 patients. Uncemented extensively porous-coated femoral stems incorporate distally allowing stable fixation. We found good early survival rates and a low incidence of nonunion using this implant.

The return of silent ischaemia? Not really.

Patients with a positive but asymptomatic test for the detection of underlying ischaemia should be treated with the same commitment as those with a similar but symptomatic test.

Effect of alum treatment on the trihalomethane formation and bacterial regrowth potential of natural and synthetic waters.

Waters from five reservoirs and "synthetic waters", prepared using terrestrially derived dissolved organic matter (DOM) extracted from vegetation and reservoir catchment soils, were studied for their treatability with alum using a jar test procedure. DOM in drinking water is a precursor for the formation of trihalomethanes (THM) following chlorine disinfection and can also be a substrate for microbial growth in the drinking water distribution system. The trihalomethane formation potential (THMFP) represents an upper concentration limit on THMs formed by chlorination, while bacterial regrowth potential (BRP) is an indicator of the bioavailability of DOM. BRP and THMFP were measured before and after alum treatment and the results were related to the source of the DOM. It was found that freshly derived terrestrial DOM in synthetic water resulted in higher THMFP and BRP than DOM in reservoir waters. For the samples investigated, conventional alum treatment did not always reduce the THM precursor levels formed in laboratory tests below the NH&MRC (1996) guideline level of 250 microg/L nor produce microbially stable waters.

Value of Mycobacterium tuberculosis fingerprinting as a tool in a rural state surveillance program.

OBJECTIVE: This study demonstrates the value of Mycobacterium tuberculosis fingerprinting used in conjunction with traditional epidemiologic methods to identify smoldering outbreaks of tuberculosis in endemic areas where background rates of tuberculosis are high. METHODS: IS6110 DNA fingerprinting was performed on isolates of M tuberculosis from verified cases of tuberculosis in Alabama from 1994 to 1998. A statewide database groups isolates into "clusters" and tracks them cumulatively over time. A large cluster was identified and was secondarily investigated using traditional epidemiologic methods. RESULTS: Twenty-five isolates were found to be identical by fingerprinting analysis. Patients were living within 10 counties across the state, and 12 cases were localized to a single county. This represented an ongoing, statewide tuberculosis outbreak previously unrecognized by local and state health officials. Secondary investigation of the cases revealed the primary sites of transmission to be a correctional facility and two homeless shelters. CONCLUSIONS: Population surveillance using M tuberculosis fingerprinting was successfully utilized to detect a significant and smoldering tuberculosis outbreak. Measures are currently in place to identify and prevent further transmission in the involved locations.

Why is recurrent myocardial ischaemia a predictor of adverse outcome in unstable angina? An observational study of myocardial ischaemia and its relation to coronary anatomy.

OBJECTIVE: To establish why recurrent myocardial ischaemia predicts adverse outcome in patients with refractory unstable angina on maximal medical treatment. DESIGN: Prospective observational study in 101 patients with refractory unstable angina who underwent continuous ST-segment monitoring and kept detailed pain charts prior to cardiac catheterization. Setting Tertiary referral centre. RESULTS: Significant coronary disease was identified in 90 subjects with 74 (82%) having multivessel disease, 41 (46%) complex lesion morphology, and 10 (11%) subjects with definite features of intra-coronary thrombus. The frequency of complex lesions or intra-coronary thrombus did not differ in relation to the extent of coronary disease. Recurrent chest pain was present in 72 of the 90 (80%) subjects, while transient ischaemia was detected in 26 (29%). The presence of transient ischaemia was a powerful predictor of complex lesions or thrombus (odds ratio 7.1;P<0.001). Subjects with severe recurrent chest pain had a greater frequency of intracoronary thrombus (odds ratio 9.5;P<0.05). CONCLUSIONS: In unstable angina once the normal mechanisms causing myocardial ischaemia (i.e. increased myocardial demand and coronary vasoconstriction) have been treated using maximal antianginal treatment, the continued development of transient myocardial ischaemia is strongly associated with complex coronary lesion morphology and intracoronary thrombus. It is already known that patients with complex lesion morphology and intracoronary thrombus have an adverse outcome in unstable angina and therefore it is this association that explains why transient ischaemia is a predictor of poor outcome in unstable angina.

Epidemiologic usefulness of spoligotyping for secondary typing of Mycobacterium tuberculosis isolates with low copy numbers of IS6110.

Restriction fragment length polymorphism (RFLP) analysis of IS6110 is commonly used to DNA fingerprint Mycobacterium tuberculosis. However, low-copy (< or =5) IS6110 M. tuberculosis strains are poorly differentiated, requiring secondary typing. When spoligotyping was used as the secondary method, only 13% of Maryland culture-positive tuberculosis (TB) patients with low-copy IS6110-spoligotyped clustered strains had epidemiologic linkages to another patient, compared to 48% of those with high-copy strains clustered by IS6110 alone (P < 0.01). Spoligotyping did not improve a population-based molecular epidemiologic study of recent TB transmission.

Oxytropism: a new twist in pollen tube orientation.

Chemical gradients and structural features within the pistil have been previously proposed as factors determining the directionality of pollen tube growth. In this study, we examine the behavior of pollen of eight species germinated in a dynamic oxygen gradient. While the germination rates of some species decreased directly with decreasing oxygen tension, other species showed no decrease in germination at oxygen tensions as low as 2 kPa. In one species, germination was consistently greater at decreased oxygen tensions than at ambient atmospheric levels. In three of the eight species tested, the developing pollen tube showed clear directional growth away from the more-oxygenated regions of the growth medium, while in one species growth was towards the more-oxygenated region. The remaining four species showed random tube growth. The pattern of oxytropic responses among the taxa suggests that this tropic behavior is both widespread and phylogenetically unpredictable.

Identification of a contaminating Mycobacterium tuberculosis strain with a transposition of an IS6110 insertion element resulting in an altered spoligotype.

Molecular fingerprinting with the IS6110 insertion sequence is useful for tracking transmission of Mycobacterium tuberculosis within a population or confirming specimen contamination in the laboratory or through instrumentation. Secondary typing with other molecular methods yields additional information as to the relatedness of strains with similar IS6110 fingerprints. Isolated, relatively rare, random events within the M. tuberculosis genome alter molecular fingerprinting patterns with any of the methods; therefore, strains which are different by two or more typing methods are usually not considered to be closely related. In this report, we describe two strains of M. tuberculosis, obtained from the same bronchoscope 2 days apart, that demonstrated unique molecular fingerprinting patterns by two different typing methods. They were closely linked through the bronchoscope by a traditional epidemiologic investigation. Genetic analysis of the two strains revealed that a single event, the transposition of an IS6110 insertion sequence in one of the strains, accounted for both the differences in the IS6110 pattern and the apparent deletion of a spacer in the spoligotype. This finding shows that a single event can change the molecular fingerprint of a strain in two different molecular typing systems, and thus, molecular typing cannot be the only means used to track transmission of this organism through a population. Traditional epidemiologic techniques are a necessary complement to molecular fingerprinting so that radical changes within the fingerprint pattern can be identified.

Trochanteric union in revision hip arthroplasty.

A total of 69 patients undergoing revision hip arthroplasty using a transtrochanteric approach who all had at least 1 previous transtrochanteric surgical approach. In 6 patients, it was the third time the trochanter was taken down, and in 2 patients, it was the fourth time. We believe this is the first review of trochanteric union in such a subgroup of patients. The mean age was 66 years (range, 46-82 years). Before revision, 49 of 69 patients (71%) had a united trochanter, whereas 20 of 69 (29%) had a pseudarthrosis. The overall pseudarthrosis rate decreased from 20 patients (29%) to 10 patients (14%) after revision surgery. The mean Harris hip score was 86 (range, 29-100). Repeated transtrochanteric osteotomy was not associated with any significant morbidity and did not affect the clinical outcome.

Phylogeography and speciation of the morphologically variable, widespread species Bufo valliceps, based on molecular evidence from mtDNA.

The widespread, lowland toad Bufo valliceps has an unusual distribution in North and Middle America that straddles two major biogeographic areas; previous morphological studies of this species suggested the existence of two species. We used mitochondrial DNA sequences to examine the phylogeography of this species and discovered the existence of two distinct clades. We recognize these as two species: B. valliceps and B. nebulifer. These molecular data support morphological data from previous studies. Our results show low levels of molecular variation in a morphologically uniform temperate species (B. nebulifer) and high levels of molecular variation in a morphologically variable tropical species (B. valliceps), providing an example of molecules matching morphology. Two biogeographic hypotheses are tested to explain the current distribution of these species, based on a calibrated rate of evolution and the percent sequence divergence between the two species. A more recent Pleistocene dispersal event, followed by vicariance associated with rising sea level, is rejected in favor of an earlier Miocene-Pliocene vicariant hypothesis associated with the formation of the Trans-Mexican Neovolcanic Belt.