First isolations in India of Candida nivariensis, a globally emerging opportunistic pathogen

We randomly screened 363 yeast isolates during 2008 for their ability to form white colonies on CHROM agar Candida medium. Two of these isolates (0.5%) were identified as Candida nivariensis based on detailed phenotypic characterization and DNA sequencing. One was recovered from the sputum of an HIV-positive patient with a pneumonic lesion and the second from the blood of a diabetic with oropharyngeal lesions. Direct DNA sequencing of the D1/D2 region of 28S rRNA gene and/or the internal transcribed spacer (ITS) regions of rDNA confirmed that both of the isolates were C. nivariensis. The carbohydrate assimilation profiles with the ID 32 C and VITEK 2 yeast identification systems revealed only glucose assimilation. In vitro antifungal susceptibility profiles by broth microdilution and Etest methods revealed susceptibility of both isolates to fluconazole, itraconazole, voriconazole, amphotericin B and 5-flucytosine, with low MICs for posaconazole and caspofungin. These results document the occurrence of Candida nivariensis for the first time in India and focus on its potential as an opportunistic human pathogen.

Sprouty-2 controls c-Met expression and metastatic potential of colon cancer cells: sprouty/c-Met upregulation in human colonic adenocarcinomas

Sprouty negatively regulates receptor tyrosine kinase signals by inhibiting Ras/ERK pathways. Sprouty is down-regulated in breast, prostate and liver cancers and appears to function as a tumor suppressor. The role of Sprouty in colonic neoplasia, however, has not been investigated. Sprouty-2 protein and mRNA transcripts were significantly up-regulated in human colonic adenocarcinomas. Strikingly, the c-Met receptor was also upregulated in tumors with increased sprouty-2. To delineate a potential causal relationship between sprouty-2 and c-Met, K-ras mutant HCT-116 colon cancer cells were transduced with purified TAT-sprouty-2 protein or stably transfected with full-length human sprouty-2 gene. Sprouty-2 up-regulation significantly increased cell proliferation by accelerating cell cycle transition. Sprouty-2 transfectants demonstrated strong up-regulation of c-Met protein and mRNA transcripts and hepatocyte growth factor stimulated ERK and Akt phosphorylation and enhanced cell migration and invasion. In contrast, knockdown of c-Met by siRNA significantly decreased cell proliferation, migration and invasion in sprouty-2 transfectants. Further, knockdown of sprouty-2 by siRNA in parental HT-29 and LS-174T colon cancer cells also decreased cell invasion. Sprouty-2 transfectants formed significantly larger tumor xenografts and demonstrated increased proliferation and angiogenesis and suppressed apoptosis. Sprouty-2 tumors metastasized to liver from cecal orthotopic implants suggesting sprouty-2 might also enhance metastatic signals. Thus in colon cancer sprouty functions as an oncogene and its effects are mediated in part by c-Met up-regulation.

Multilocus analysis of honeyeaters (Aves: Meliphagidae) highlights spatio-temporal heterogeneity in the influence of biogeographic barriers in the Australian monsoonal zone

Multilocus studies in phylogenetics and comparative phylogeography have the power to explore a broader spectrum of evolutionary questions than either discipline has alone. To examine the origins of sympatry in a group of closely related birds of mostly mesic eucalypt woodlands in Australia, we reconstructed the relationships among species of Entomyzon and Melithreptus honeyeaters (Aves: Passeriformes: Meliphagidae) using a mitochondrial marker, ND2, and six non-coding nuclear loci (total 4719 base pairs). By sampling across the geographical range of each species, we studied not only their phylogenetic relationships to each other but also the spatial distribution of their genetic diversity. We tested several biogeographic hypotheses concerning the role of Pleistocene environmental change in Australia. Phylogenetic gene trees support the current understanding of E. cyanotis as the sister to Melithreptus. Non-monophyly of M. lunatus in Australia's southern temperate woodlands highlights the need for a revision of systematics within Melithreptus. Phylogeographic analysis of the three northern species in Australia's monsoon tropics, M. gularis, M. albogularis and E. cyanotis, suggests that the roles of the Carpentarian and Torresian Barriers in shaping geographic structure in each of the species have been more complex and temporally dynamic than earlier morphology-based arguments of vicariance had suggested. We discuss their roles as ecological filters as well as barriers.

Polymyalgia rheumatica prevalence in a population-based sample

OBJECTIVE

To determine polymyalgia rheumatica (PMR) prevalence using population-based administrative data, and to estimate the error associated with case ascertainment approaches when using these databases.

METHODS

Cases were ascertained using physician billing and hospitalization data from the province of Manitoba (population 1.1 million). Focusing on the population age >/=45 years, we compared 3 different case definition algorithms and also used statistical methods that accounted for imperfect case ascertainment to estimate the prevalence and the properties of the ascertainment algorithms. A hierarchical Bayesian latent class regression model was developed that also allowed us to assess differences across patient demographics (sex and region of residence).

RESULTS

Using methods that account for the imperfect nature of both billing and hospitalization databases, we estimated the prevalence of PMR in women age >/=45 years to be lower in urban areas (754.5 cases/100,000; 95% credible interval [95% CrI] 674.1-850.3) compared with rural areas (1,004 cases/100,000; 95% CrI 886.3-1,143). This regional trend was also seen in men age >/=45 years, where the prevalence was estimated at 273.6 cases/100,000 (95% CrI 219.8-347.6) in urban areas and 380.7 cases/100,000 (95% CrI 311.3-468.1) in rural areas. Billing data appeared more sensitive in ascertaining cases than hospitalization data, and a large proportion of diagnoses was made by physicians other than rheumatologists.

CONCLUSION

These data suggest a higher prevalence of PMR in rural versus urban regions. Our approach demonstrates the usefulness of methods that adjust for the imperfect nature of multiple information sources, which also allow for estimation of the sensitivity of different case ascertainment approaches.

Estimating the sensitivity and specificity of Kato-Katz stool examination technique for detection of hookworms, Ascaris lumbricoides and Trichuris trichiura infections in humans in the absence of a 'gold standard'

The accuracy of the Kato-Katz technique in identifying individuals with soil-transmitted helminth (STH) infections is limited by day-to-day variation in helminth egg excretion, confusion with other parasites and the laboratory technicians' experience. We aimed to estimate the sensitivity and specificity of the Kato-Katz technique to detect infection with Ascaris lumbricoides, hookworm and Trichuris trichiura using a Bayesian approach in the absence of a 'gold standard'. Data were obtained from a longitudinal study conducted between January 2004 and December 2005 in Samar Province, the Philippines. Each participant provided between one and three stool samples over consecutive days. Stool samples were examined using the Kato-Katz technique and reported as positive or negative for STHs. In the presence of measurement error, the true status of each individual is considered as latent data. Using a Bayesian method, we calculated marginal posterior densities of sensitivity and specificity parameters from the product of the likelihood function of observed and latent data. A uniform prior distribution was used (beta distribution: alpha=1, beta=1). A total of 5624 individuals provided at least one stool sample. One, two and three stool samples were provided by 1582, 1893 and 2149 individuals, respectively. All STHs showed variation in test results from day to day. Sensitivity estimates of the Kato-Katz technique for one stool sample were 96.9% (95% Bayesian Credible Interval [BCI]: 96.1%, 97.6%), 65.2% (60.0%, 69.8%) and 91.4% (90.5%, 92.3%), for A. lumbricoides, hookworm and T. trichiura, respectively. Specificity estimates for one stool sample were 96.1% (95.5%, 96.7%), 93.8% (92.4%, 95.4%) and 94.4% (93.2%, 95.5%), for A. lumbricoides, hookworm and T. trichiura, respectively. Our results show that the Kato-Katz technique can perform with reasonable accuracy with one day's stool collection for A. lumbricoides and T. trichiura. Low sensitivity of the Kato-Katz for detection of hookworm infection may be related to rapid degeneration of delicate hookworm eggs with time.

Scleroderma prevalence: demographic variations in a population-based sample

OBJECTIVE

To estimate the prevalence of systemic sclerosis (SSc) using population-based administrative data, and to assess the sensitivity of case ascertainment approaches.

METHODS

We ascertained SSc cases from Quebec physician billing and hospitalization databases (covering approximately 7.5 million individuals). Three case definition algorithms were compared, and statistical methods accounting for imperfect case ascertainment were used to estimate SSc prevalence and case ascertainment sensitivity. A hierarchical Bayesian latent class regression model that accounted for possible between-test dependence conditional on disease status estimated the effect of patient characteristics on SSc prevalence and the sensitivity of the 3 ascertainment algorithms.

RESULTS

Accounting for error inherent in both the billing and the hospitalization data, we estimated SSc prevalence in 2003 at 74.4 cases per 100,000 women (95% credible interval [95% CrI] 69.3-79.7) and 13.3 cases per 100,000 men (95% CrI 11.1-16.1). Prevalence was higher for older individuals, particularly in urban women (161.2 cases per 100,000, 95% CrI 148.6-175.0). Prevalence was lowest in young men (in rural areas, as low as 2.8 cases per 100,000, 95% CrI 1.4-4.8). In general, no single algorithm was very sensitive, with point estimates for sensitivity ranging from 20-73%.

CONCLUSION

We found marked differences in SSc prevalence according to age, sex, and region. In general, no single case ascertainment approach was very sensitive for SSc. Therefore, using data from multiple sources, with adjustment for the imperfect nature of each, is an important strategy in population-based studies of SSc and similar conditions.

Mammographically non-calcified ductal carcinoma in situ: sonographic features with pathological correlation in 35 patients

AIM

To present the sonographic findings of mammographically non-calcified ductal carcinoma in situ (DCIS) with histopathologic correlation.

MATERIALS AND METHODS

The mammographic and ultrasonographic presentations of 47 radiographically non-calcified DCIS lesions in 35 patients were retrospectively analysed. Histological characteristics (architectural appearance, nuclear grade, percent of involved lobules, and presence of necrosis) were reviewed.

RESULTS

Seventeen lesions were not mammographically visible (17/47, 36%). Ultrasonographically, these lesions showed an irregular shape (28/47, 60%), microlobulated margins (34/47, 72%) and abrupt interfaces (42/47, 90%). Only 11% (5/47) displayed posterior shadowing. The echotexture of these lesions was most frequently complex (29/47, 62%); therefore, they were divided into two types: type I (24 cases), which were predominantly solid with cystic components, and type II (five cases), which were predominantly cystic with a solid intra-cystic component. A trend to have greater than 50% DCIS cells in cancerous lobules was observed in masses displaying type I echotexture (difference=36%, 95% confidence interval 10.6-62.5) and microlobulated margins (difference=32%, 95% confidence interval 5.1-58.7).

CONCLUSION

Ultrasonographically detected radiographically non-calcified DCIS commonly displays an irregular shape, microlobulated margins, and complex echotexture, giving a "pseudomicrocystic" appearance. Microlobulated margins and "pseudomicrocystic" echotexture seem to be associated with a cancerization of the lobules.

Application of a nomogram for exercise capacity in women with systemic lupus erythematosus

The aim of this study is to examine the exercise capacity in women with systemic lupus erythematosus (SLE). Women with SLE underwent exercise testing; their performance was compared to nomogram predictions. We assessed the potential effects of disease activity and cumulative damage on exercise capacity. We evaluated 52 female SLE patients aged >35 years. The mean workload achieved was somewhat higher than the nomogram predictions. However, over one fifth of the women performed at a very poor level, which in the general population is associated with a twofold increased risk of cardiovascular disease. Compared to other subjects, participants who did poorly tended toward higher disease activity, higher body mass index, and greater smoking prevalence, although the results were not definitive. Exercise testing may be used to identify a subpopulation of lupus patients with a low level of fitness. Extrapolating from general population data, these individuals are likely at particular risk for cardiovascular disease and may, therefore, benefit the most from aggressive cardiovascular risk factor reduction.

Epidermal growth factor receptor-targeted therapy

High epidermal growth factor receptor (EGFR) expression is a feature of human tumours and is an adverse prognostic factor for radiotherapy outcome. High expression is associated with benefit from accelerated radiotherapy in patients with head and neck squamous cell carcinoma. Anti-EGFR strategies potentiate the effects of radiotherapy and the inhibition of deoxyribonucleic acid repair appears to be important amongst a wide range of mechanisms, which include effects on angiogenesis, differentiation and the immunological response. There is considerable interest in exploring combined modality therapies involving radiation and EGFR antagonists for the curative treatment of cancer patients. Important issues in designing new trials are to investigate optimal scheduling and to establish biobanks to develop biomarkers for future patient selection.

Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota

The integration of phylogenetics, phylogeography and palaeoenvironmental studies is providing major insights into the historical forces that have shaped the Earth's biomes. Yet our present view is biased towards arctic and temperate/tropical forest regions, with very little focus on the extensive arid regions of the planet. The Australian arid zone is one of the largest desert landform systems in the world, with a unique, diverse and relatively well-studied biota. With foci on palaeoenvironmental and molecular data, we here review what is known about the assembly and maintenance of this biome in the context of its physical history, and in comparison with other mesic biomes. Aridification of Australia began in the Mid-Miocene, around 15 million years, but fully arid landforms in central Australia appeared much later, around 1-4 million years. Dated molecular phylogenies of diverse taxa show the deepest divergences of arid-adapted taxa from the Mid-Miocene, consistent with the onset of desiccation. There is evidence of arid-adapted taxa evolving from mesic-adapted ancestors, and also of speciation within the arid zone. There is no evidence for an increase in speciation rate during the Pleistocene, and most arid-zone species lineages date to the Pliocene or earlier. The last 0.8 million years have seen major fluctuations of the arid zone, with large areas covered by mobile sand dunes during glacial maxima. Some large, vagile taxa show patterns of recent expansion and migration throughout the arid zone, in parallel with the ice sheet-imposed range shifts in Northern Hemisphere taxa. Yet other taxa show high lineage diversity and strong phylogeographical structure, indicating persistence in multiple localised refugia over several glacial maxima. Similar to the Northern Hemisphere, Pleistocene range shifts have produced suture zones, creating the opportunity for diversification and speciation through hybridisation, polyploidy and parthenogenesis. This review highlights the opportunities that development of arid conditions provides for rapid and diverse evolutionary radiations, and re-enforces the emerging view that Pleistocene environmental change can have diverse impacts on genetic structure and diversity in different biomes. There is a clear need for more detailed and targeted phylogeographical studies of Australia's arid biota and we suggest a framework and a set of a priori hypotheses by which to proceed.