Liquid‐based cytology of pigmented phaeohyphomycotic lesion of the palm masquerading as a metastatic tumor

Phaeohyphomycosis is a chronic subcutaneous fungal infection caused by dematiaceous fungi, commonly involving the extremities, which present as single or multiple lesions mimicking a benign tumor. Fine‐needle aspiration cytology (FNAC) is an easy method for the diagnosis of the lesion. Morphology of the fungus is characteristic with no difficulty for cytopathologist for identification; with a close differential diagnosis of Candida and Aspergillosis. The special stains like periodic acid schiff (PAS) highlights the fungus and the Masson Fontana confirm the melanin pigment and dematiaceous nature of the fungi. Liquid‐based cytology (LBC) preparation of the aspirated material was attempted, which is not usually performed on day to day basis. However, in our case the conventional smears were better for appreciating the fungal morphology.     

Cutaneous nocardiosis with discharging sinus clinically mimicking tuberculosis diagnosed by cytology

Nocardiosis is primarily a pulmonary infection commonly seen in immunocompromised individuals. However, lymphocutaneous nocardiosis is observed in immunocompetent individuals often after trauma. The clinical and cytomorphological features of lymphocutaneous nocardiosis closely mimic the most common infections in India such as tuberculosis and mycetoma (very common cutaneous infection with discharging sinus). As it is crucial to differentiate nocardiosis from tuberculosis, to avoid unnecessary antitubercular treatment, special stains like modified Ziehl–Neelsen stain and Gram stain can be employed to differentiate the morphology of Nocardia from tuberculosis. Fine‐needle cytology from these cutaneous lesions helps in yielding adequate material for rapid and accurate diagnosis of immediate specific antibiotic treatment. We report a rare case that presented with clinical diagnosis of tuberculosis but turned out to be nocardiosis on cytomorphology with simple and most feasible fine‐needle aspiration method of tissue diagnosis and scrape cytology.     

Potentiation of a survival signal in the ischemic heart by resveratrol through p38 mitogen-activated protein kinase/mitogen- and stress-activated protein kinase 1/cAMP response element-binding protein signaling

Resveratrol (3,4',5-trihydroxy-trans-stilbene), a naturally occurring polyphenolic compound found abundantly in grape skins and red wines, has been found to pharmacologically precondition the heart against ischemia reperfusion injury through the potentiation of a survival signal involving cAMP response element-binding protein-dependent phosphatidylinositol 3-kinase-Akt-BclII pathway. The present study was designed to determine whether, similar to ischemic preconditioning, resveratrol uses mitogen-activated protein kinases (MAPKs) as upstream signaling targets. The isolated rat hearts were preperfused for 15 min with Krebs-Henseleit bicarbonate buffer in the absence (control) or presence of extracellular signal-regulated kinase (ERK) 1/2 inhibitor 2'-amino-3'-methoxyflavone (PD98059), p38 MAPK inhibitor 4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)-1H-imidazole (SB-202190), mitogen- and stress-activated protein kinase 1 (MSK-1) inhibitor N-[2-(4-bromocinnamylamino)ethyl]-5-isoquinoline (H89), protein kinase A inhibitor (9S,10S,12R)-2,3,9,10,11,12-hexahydro-10hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3fg: 3',2',1'-kl]-pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylic acid hexyl ester (KT5720), resveratrol only, resveratrol plus PD98059, resveratrol plus SB-202190, resveratrol plus H89, or resveratrol plus KT5720. Consistent with previous reports, resveratrol provided cardioprotection as evidenced by its ability to improve postischemic ventricular function, reduction of myocardial infarct size, and cardiomyocyte apoptosis. The cardioprotection afforded by resveratrol was partially abolished with PD98059 or SB-202190, suggesting that ERK1/2 and p38 MAPK play roles in resveratrol-mediated preconditioning. An MSK-1 inhibitor, H89, abolished resveratrol-mediated preconditioning, indicating MSK-1 to be the downstream target molecule for both ERK1/2 and p38 MAPK. KT5720 had no effect on resveratrol-mediated cardioprotection. Corroborating these results, Western blot analysis revealed phosphorylation of ERK1/2, p38 MAPK, MAPK-activated protein (MAPKAP) kinase 2, and MSK-1 with resveratrol and inhibition of phosphorylation with corresponding inhibitors. These results showed for the first time that resveratrol triggers an MAPK signaling pathway involving ERK1/2 and p38 MAPK, the former using MSK-1 as the downstream target and the latter, using both MAPKAP kinase 2 and MSK-1 as downstream targets.     

Outer membrane protein A (OmpA) from Shigella flexneri 2a: A promising subunit vaccine candidate

Shigellosis is the leading cause of childhood mortality and morbidity. Despite many years of extensive research a practical vaccine is not yet available against the disease. Recent studies illustrate that bacterial outer membrane proteins are budding target as vaccine antigen. Outer membrane proteins A (OmpA) are among the most immunodominant antigens in the outer membrane of gram negative bacteria and possess many characteristics desired of a vaccine candidate. We observe that OmpA of Shigella flexneri 2a is crossreactive and common antigen among Shigella spp. and the epitope is widely exposed on the cell surface as well as capable of evoking protective immunity in mice. The protective immunity involves participation of both the humoral and cellular immune responses, since OmpA boosts rapid induction of IgG and IgA in both the systemic and mucosal compartments and also activates Th1 cells. The immunopotentiating activity of OmpA is mediated by its ability to bind and stimulate macrophages and up-regulate the surface expression of MHCII, CD80 and CD40, leading to activation of CD4⁺ T cells to secrete cytokines and express chemokine receptor and IL-12Rβ2, thereby orchestrating the bridge between innate and adaptive immune responses. This ability is dependent on Toll-like receptor 2 (TLR2), as demonstrated by lack of response by TLR2 knockdown macrophages to OmpA. Hence this property of OmpA to link innate and adaptive immunity via TLR2 offers a novel vista to develop vaccine against shigellosis.     

MRI confirms loss of blood–brain barrier integrity in a mouse model of disseminated candidiasis

Disseminated candidiasis primarily targets the kidneys and brain in mice and humans. Damage to these critical organs leads to the high mortality associated with such infections, and invasion across the blood–brain barrier can result in fungal meningoencephalitis. Candida albicans can penetrate a brain endothelial cell barrier in vitro through transcellular migration, but this mechanism has not been confirmed in vivo. MRI using the extracellular vascular contrast agent gadolinium diethylenetriaminepentaacetic acid demonstrated that integrity of the blood–brain barrier is lost during C. albicans invasion. Intravital two‐photon laser scanning microscopy was used to provide the first real‐time demonstration of C. albicans colonizing the living brain, where both yeast and filamentous forms of the pathogen were found. Furthermore, we adapted a previously described method utilizing MRI to monitor inflammatory cell recruitment into infected tissues in mice. Macrophages and other phagocytes were visualized in kidney and brain by the administration of ultrasmall iron oxide particles. In addition to obtaining new insights into the passage of C. albicans across the brain microvasculature, these imaging methods provide useful tools to study further the pathogenesis of C. albicans infections, to define the roles of Candida virulence genes in kidney versus brain infection and to assess new therapeutic measures for drug development. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

Recent progress in development of 2,3-diaminomaleonitrile (DAMN) based chemosensors for sensing of ionic and reactive oxygen species

2,3-Diaminomaleonitrile (DAMN) has proved to be a valuable organic π-conjugated molecule having many applications in the area of chemosensors for sensing of ionic and neutral species because of its ability to act as a building block for well-defined molecular architectures and scaffolds for preorganised arrays of functionality. In this article, we discussed the utilization of 2,3-diaminomaleonitrile (DAMN) for the design and development of chemosensor molecules and their application in the area of metal ion, anion and reactive oxygen species sensing. Along with these, we present different examples of DAMN based chemosensors for multiple ion sensing. We also discuss the ion sensing mechanism and potential uses in other related areas of research.

2,3-Diamniomaleonitrile (DAMN) is valuable π-conjugated organic scaffold molecule for designing of efficient chemosensors for sensing of ionic and Reactive Oxygen Species (ROS).     

RNASEK is required for internalization of diverse acid-dependent viruses

Viruses must gain entry into cells to establish infection. In general, viruses enter either at the plasma membrane or from intracellular endosomal compartments. Viruses that use endosomal pathways are dependent on the cellular factors that control this process; however, these genes have proven to be essential for endogenous cargo uptake, and thus are of limited value for therapeutic intervention. The identification of genes that are selectively required for viral uptake would make appealing drug targets, as their inhibition would block an early step in the life cycle of diverse viruses. At this time, we lack pan-antiviral therapeutics, in part because of our lack of knowledge of such cellular factors. RNAi screening has begun to reveal previously unknown genes that play roles in viral infection. We identified dRNASEK in two genome-wide RNAi screens performed in Drosophila cells against West Nile and Rift Valley Fever viruses. Here we found that ribonuclease kappa (RNASEK) is essential for the infection of human cells by divergent and unrelated positive- and negative-strand-enveloped viruses from the Flaviviridae, Togaviridae, Bunyaviridae, and Orthomyxoviridae families that all enter cells from endosomal compartments. In contrast, RNASEK was dispensable for viruses, including parainfluenza virus 5 and Coxsackie B virus, that enter at the plasma membrane. RNASEK is dispensable for attachment but is required for uptake of these acid-dependent viruses. Furthermore, this requirement appears specific, as general endocytic uptake of transferrin is unaffected in RNASEK-depleted cells. Therefore, RNASEK is a potential host cell Achilles’ heel for viral infection.Viral pathogens are quite diverse in their replication strategies; however, all viruses must enter cells to initiate their replication cycles. The first step involves binding of virus particles to the cell surface. Such interactions can involve attachment factors, which have low affinity but concentrate viruses on the surface of cells, and receptors that intricately interact with viral envelope glycoproteins, which, in addition to binding, promote other aspects of infection such as internalization. Although a plethora of receptors and pathways can be used, most viruses take advantage of the cellular endocytic machinery and penetrate from within the cytosol (reviewed in refs. 1–3). Clathrin-mediated endocytosis, macropinocytosis, and caveolin-mediated endocytosis are the best-studied forms of uptake used by viruses. Clathrin-mediated endocytosis is the most common mechanism used by small viruses, as clathrin-coated vesicles have a diameter of 60–200 nm and can be enlarged to fit even larger particles (4, 5). This pathway is constitutive on most cells, and some viruses use preexisting clathrin-coated pits for entry (e.g., dengue virus), whereas others induce the formation of these structures (e.g., influenza virus) (6, 7). Macropinocytosis is an actin-dependent endocytic process for the nonselective uptake of nutrients in response to receptor engagement. It is the predominant pathway for many larger viruses, including vaccinia virus, but is also used by others, including influenza virus under some conditions (8–10). It also remains unclear which pathways are used by some viruses, including Rift Valley Fever virus (RVFV) (11–13).The molecular mechanisms involved in these uptake mechanisms are complex and rely on key molecules and organelles that are essential for cellular viability, as these uptake mechanisms bring nutrients and other metabolites into the cytosol for cellular growth and survival. Indeed, these processes and proteins involved are highly conserved from yeast to humans (14, 15). Depending on the virus entry requirements, some viruses fuse within early endosomal vesicles, whereas others traffic to more acidic compartments or macropinosomes for entry. Because many viruses are dependent on these endosomal trafficking pathways for entry, much effort has been made in identifying the specific cellular genes required for viral entry (16). Therapeutics targeting entry are appealing because it is the first step in the infection cycle, and many viruses use common pathways; thus, inhibition may be broadly antiviral, rather than active against only a specific virus. Furthermore, many viruses have high mutation rates and rapidly evolve resistance to therapeutics targeting virally encoded genes. Conversely, therapeutics against host encoded targets would likely be more difficult for the virus to evade.Recent advances in functional genomic technologies have facilitated the use of unbiased genome-wide RNAi screens to identify cellular genes required for viral infection (17). Such approaches allow for the discovery of otherwise unknown genes that play essential roles in infection. We recently performed such screens in insect cells against two disparate insect-borne human pathogens: the flavivirus West Nile virus (WNV) and the bunyavirus RVFV (18, 19). These are both arthropod-borne human pathogens for which there are no vaccines or therapeutics. Furthermore, these viruses are quite divergent: WNV is a flavivirus that is a globally important cause of encephalitis (20), and RVFV is a bunyavirus that causes significant morbidity and mortality in livestock and humans in Africa (21). In our screens, there were only three genes that promoted infection by both viruses: dRAB5, dSTX7, and dRNASEK (CG40127). The functions of RAB5 and STX7 have been described, but little is known about ribonuclease kappa (RNASEK). Both RAB5 and STX7 are involved in endosomal transport and have roles in viral entry (22, 23). Both WNV and RVFV are enveloped RNA viruses that require an acidic compartment for entry (12, 13, 24). RNASEK is a single-copy, 137-aa protein conserved from insects to humans (25–27) with an unknown function. We set out to determine the role of RNASEK in viral infection and found that RNASEK is required for internalization of a diverse panel of viruses of medical concern.     

Medullary carcinoma of thyroid metastasis to breast: A cytological experience

Medullary carcinoma of thyroid is a relatively uncommon malignancy, which can be sporadic and syndromic in nature. It commonly spreads to regional lymph nodes followed by spreading to distant sites. Breast is an uncommon site of metastasis of this malignancy. Our case is a 38‐year‐old woman married parous woman presenting to the outpatient department with complaints of lump in both the breasts. Fine‐needle aspiration (FNA) was attempted, which revealed a malignancy more suggestive of a metastasis, which was confirmed on CT scan. A detailed history revealed that the patient is a known case of medullary carcinoma of thyroid. The report was given as metastatic medullary carcinoma to the breast after confirming with a calcitonin immunostain. Given the versatility of primary lesions in the breast, minimally invasive FNA cytology (FNAC) technique with adequate sampling helps in identifying metastatic lesions. Differentiating primary from metastatic lesions changes the course of management to the patient. Metastatic lesions should always be kept in mind in the occurrence of known malignancies, however rare the site of occurrence may be. Morphological clues and immunohistochemical work up aid in arriving at correct diagnosis.