Cytodiagnosis of cutaneous histoplasmosis in HIV positive patient initially presenting with multiple umbilicated disseminated skin nodules

Histoplasmosis is usually an opportunistic fungal infection in patients with defective cell mediated immunity, and has been considered as one of the acquired immunodeficiency syndrome (AIDS) defining illness. However, cutaneous involvement in human immunodeficiency virus (HIV) positive patients is less common, and very rarely can be the initial presenting symptom for the diagnosis of AIDS. We present here an unusual case of multiple diffuse cutaneous nodular lesions predominantly in face, trunk, and upper extremities diagnosed initially on aspiration cytology as histoplasmosis. Subsequent serological test revealed positivity for HIV 1 and 2, along with a low CD4 count and low CD4:CD3 ratio. The cytomorphological features were further corroborated by histology and histochemical stains. Hence, cutaneous histoplasmosis can cause multiple wide spread nodular or umbilicated lesions in AIDS patients as the initial presentation. Fine needle aspiration cytology (FNAC) is a rapid, cost effective tool for diagnosis of the fungi from such lesions and initiating work up for immunocompromised states including AIDS. Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.     

Detection of New Delhi Metallo‐beta‐Lactamase and Extended‐Spectrum beta‐Lactamase Genes in Escherichia coli Isolated from Mastitic Milk Samples

In this study, eight Escherichia coli isolates were obtained from milk samples of dairy cattle suffering from clinical/subclinical mastitis. Isolates were characterized for antimicrobial resistance traits and virulence genes. Results revealed that one isolate was harbouring New Delhi metallo‐beta‐lactamase gene (bla_NDM). Cloning and sequencing of the PCR amplicon confirmed the identity of the gene (GenBank accession no. KC769583 ) having 100% homology with bla_NDM‐5 (GenBank accession no. JN104597.1 ), and this isolate was susceptible to colistin, chloramphenicol and tetracycline only. Moreover, another isolate carried extended‐spectrum beta‐lactamase (ESBL) gene – bla_CTX‐M, and all isolates possessed bla_TEM gene. Of the eight isolates, only one isolate was positive for shiga toxin gene (stx2), and none were harbouring stx1 gene. Occurrence of New Delhi metallo‐beta‐lactamase (bla_NDM) in one E. coli isolate and ESBL genes in other isolates poses a potential threat to human health following possible entry and spread through food chain.     

Loss of p53 cooperates with K‐ras activation to induce glioma formation in a region‐independent manner

Gliomas are recognized as a heterogeneous group of neoplasms differing in their location and morphological features. These differences, between and within varying grades of gliomas, have not been explained solely on the grounds of an oncogenic stimulus. Interactions with the tumor microenvironment as well as inherent characteristics of the cell of origin are likely a source of this heterogeneity. There is an ongoing debate over the cell of origin of gliomas, where some suggest a progenitor, while others argue for a stem cell origin. Thus, it is presumed that neurogenic regions of the brain such as the subventricular zone (SVZ) containing large numbers of neural stem and progenitor populations are more susceptible to transformation. Our studies demonstrate that K‐ras^G12D cooperates with the loss of p53 to induce gliomas from both the SVZ and cortical region, suggesting that cells in the SVZ are not uniquely gliomagenic. Using combinations of doxycycline‐inducible K‐ras^G12D and p53 loss, we show that tumors induced by the cooperative actions of these genes remain dependent on active K‐ras expression, as deinduction of K‐ras^G12D leads to complete tumor regression despite absence of p53. These results suggest that the interplay between specific combinations of genetic alterations and susceptible cell types, rather than the site of origin, are important determinates of gliomagenesis. Additionally, this model supports the view that, although several genetic events may be necessary to confer traits associated with oncogenic transformation, inactivation of a single oncogenic partner can undermine tumor maintenance, leading to regression and disease remission. GLIA 2013;61:1862–1872     

DOACs for stroke prevention in patients with AF and cancer

Stroke prophylaxis in atrial fibrillation is an important consideration in patients with cancer. However, there is little consensus on the choice of anticoagulation, due to the numerous difficulties associated with active cancer. Direct oral anticoagulants (DOACs) have been shown to be a promising option. Here, we conduct a simple cross-sectional analysis of 29 cancer patients receiving DOACs for stroke prophylaxis in atrial fibrillation at a tertiary-care institution in London. Our study demonstrates an encouraging efficacy and safety profile of DOACs used in this setting. We conclude by suggesting that, while DOACs may be useful, anticoagulation in cancer patients should continue to be individualised.     

The phenomenon of drop in output at larger field sizes for telecobalt units

It is known that the output factors (OPFs) for external-beam radiotherapy units increase with field size due to increased scattered radiation from the collimator system. Saturation in the OPF value is generally reported beyond approximately 30 × 30 cm². For the first time, to the best of our knowledge, we report on a drop in OPF values, although marginal, measured for a telecobalt machine beyond the 38 × 38 cm² field size. We believe that reporting and explaining the results will lead to a better understanding of the scatter composition of the radiation from telecobalt machines. This also has the potential to impact the estimation of low dose regions in patients, in addition to being a purely scientific inquiry. We used Monte Carlo (MC) simulations to validate the measured values. The MC data showed that the decrease in OPF was due to decreased scatter from the machine head.