Peripancreatic tuberculosis.

Peripancreatic tuberculosis (PTB) is a very rare variant of tuberculosis and its clinical and radiological findings are similar to those of pancreatic malignancy. Diagnosis of PTB is usually incidental and is made after surgical resection. We are presenting a male patient who had complaints of prolonged fever, significant weight loss and yellowish discolouration of eyes and dark-coloured urine. Investigations revealed that there was a pancreatic mass causing obstructive jaundice. However, the aetiology of the mass, whether tubercular or malignant, was not clear. Hence, the patient was planned for endoscopic ultrasound-guided fine needle aspiration cytology. Cytology and aspirate were sent for a cartridge-based nucleic acid amplification test which revealed the presence of Mycobacterium tuberculosis, sensitive to rifampicin. The patient improved completely after treatment with antitubercular therapy.

Primary hepatoid adenocarcinoma of lung: A rare malignancy mimicking tuberculosis.

Hepatoid adenocarcinoma of lung (HAL) is a rare aggressive malignant tumour which histologically resembles hepatocellular carcinoma (HCC). Hepatoid adenocarcinoma (HAC) mostly produces high levels of alphafetoprotein (AFP) and is frequently found in extrahepatic organs including stomach, testes, ovaries, lungs and pancreas. Our patient was a male in his 40s with a chronic smoking history, presented with complaints of fever, weight loss, cough and anorexia for one month. On the basis of history, examination and initial investigation patient were started on empirical antitubercular therapy. However, within a span of 10 days, patient's condition worsened, and he developed a pulmonary embolism, which despite adequate treatment did not improve and the patient succumbed to his illness. Postmortem biopsy revealed a rare primary lung tumour, HAL.

A critical analysis of urea transporter B inhibitors: molecular fingerprints, pharmacophore features for the development of next-generation diuretics.

Urea transporter is a membrane transport protein. It is involved in the transferring of urea across the cell membrane in humans. Along with urea transporter A, urea transporter B (UT-B) is also responsible for the management of urea concentration and blood pressure of human. The inhibitors of urea transporters have already generated a huge attention to be developed as alternate safe class of diuretic. Unlike conventional diuretics, these inhibitors are suitable for long-term therapy without hampering the precious electrolyte imbalance in the human body. In this study, UT-B inhibitors were analysed by using multi-chemometric modelling approaches. The possible pharmacophore features along with favourable and unfavourable sub-structural fingerprints for UT-B inhibition are extracted. This information will guide the medicinal chemist to design potent UT-B inhibitors in future.

Urea transporter and its specific and nonspecific inhibitors: State of the art and pharmacological perspective.

Hypertension is a major concern for a wide array of patients. The traditional drugs are commonly referred as 'water pills' and these molecules have been successful in alleviating hypertension. However, this comes at the high expense of precious electrolytes in our body. To dissipate this major adverse effect, the urea transporter inhibitors play especially important roles in maintaining the fluid balance by maintaining the concentration of urea in the inner medullary collecting duct. The purpose of this communication is to provide insights into the structural feature of these target proteins and inhibition of both urea transporter types A (UT-A) and B (UT-B) selectively and non-selectively with a special focus on the UT-A inhibitors as they are the primary target for diuresis. It was observed that a wide class of drugs such as thiourea analogues, 2,7-disubstituted fluorenones can inhibit both the protein non-selectively whereas 8-hydroxyquinoline, aminothiazolone, 1,3,5-triazine, triazolothienopyrimidine, thienoquinoline, arylthiazole, γ-sultambenzosulfonamide and 1,2,4-triazoloquinoxaline classes of compounds inhibit UT-A. The goal of this study is to highlight the important aspects that may be useful to understanding the perspectives of urea transporter inhibitors in rational drug discovery.

Facile and green approach to prepare fluorescent carbon dots: Emergent nanomaterial for cell imaging and detection of vitamin B2.

Carbon dots (CDs) are a new representative in carbonaceous family and have initiated remarkable research interests over the past one decade in a large variety of fields. Herein, we have utilized a facile, one-step carbonization method to prepare fluorescent carbon dots using poly(vinyl alcohol) (PVA) both as a carbon source and as a surface passivating agent. The as prepared CDs emit bright blue fluorescence under ultraviolet illumination. The structure and optical properties of the CDs are thoroughly investigated by several methods such as high-resolution transmission electron microscopy; dynamic light scattering; UV-vis, fluorescence and Fourier transform infrared spectroscopy. The CDs exhibit excellent water solubility and demonstrate average hydrodynamic diameter of 11.3 nm, holding great promise for biological applications. The biocompatibility evaluation and in vitro imaging study reveals that the synthesized CDs can be used as effective fluorescent probes in bio-imaging without noticeable cytotoxicity. In addition, a unique sensor for the detection of vitamin B2 in aqueous solution is proposed on the basis of spontaneous fluorescence resonance energy transfer from CD to vitamin B2. These findings therefore suggest that the CDs can find potential applications in cellular imaging along with sensing of vitamin B2.

Fluorescent graphene oxide via polymer grafting: an efficient nanocarrier for both hydrophilic and hydrophobic drugs.

Functionalized graphene-based drug delivery vehicles have conquered a significant position because functionalization improves its biocompatibility and stability in cell medium, leaving sufficient graphitic basal plane for drug loading through π-π stacking. In this study, poly(N-isopropylacrylamide) (PNIPAM) is covalently grafted from the surface of graphene oxide (GO) via a facile, eco-friendly and an easy procedure of free radical polymerization (FRP) using ammonium persulfate initiator. Various spectroscopic and microscopic studies confirm the successful grafting of PNIPAM from GO surface. PNIPAM-grafted GO (GPNM) exhibits enhanced thermal stability, improved dispersibility both in aqueous and cell medium, and better biocompatibility and cell viability compared to GO. Interestingly, GPNM displays an exciting fluorescence property in aqueous medium, which is a hike of intensity at 36 °C due to the lower critical solution temperature (LCST) of PNIPAM chains (32 °C). Moreover both hydrophilic (doxorubicin (DOX)) and hydrophobic (indomethacin (IMC)) drugs loaded on the surface of GPNM hybrid exhibits its efficacy as an efficient carrier for both types of drugs. Cellular uptakes of free DOX and DOX-loaded GPNM (GPNM-DOX) are evidenced both from optical and fluorescence imaging of live cells, and the efficiency of drug is significantly improved in the loaded system. The release of DOX from GPNM-DOX was achieved at pH 4, relevant to the environment of cancer cells. The pH-triggered release of hydrophobic drug was also studied using UV-vis spectroscopy via alginate encapsulation, showing a great enhancement at pH = 7.4. The IMC is also found to be released by human serum albumin using dialysis technique. The GPNM nanomaterial shows the property of simultaneous loading of DOX and IMC as well as pH-triggered simultaneous release of both of the drugs.

Nanojacketing and dejacketing of ds-DNA: a nondestructive characterization of a nanojacketed sample by impedance spectroscopy.

A facile approach of nanojacketing DNA in intact conformation is evolved by the in situ polymerization of o-methoxyaniline (OMA) at 30 °C using HAuCl4 as an oxidant and DNA as a soft template. It concomitantly produces poly(o-methoxyaniline) (POMA) and a Au nanojacket encapsulating the double stranded DNA (ds-DNA). The POMA chains remain adhered to the Au nanojacket, facilitating the dissolution of nanojacketed DNA (DNA-Au-POMA) in organic solvent without affecting its conformation. Digestion of the nanojacketed system with saturated iodine solution dejackets the ds-DNA with retention of its conformation, leaving the POMA nanotube. The nanojacketing and dejacketing phenomena are established by transmission electron microscopy (TEM), UV-vis spectroscopy, and CD spectroscopy, and the nanostructure is further characterized by FTIR, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The impedance study of the DNA-Au-POMA sample suggests the Cole-Cole plots at both the impedance and modulus planes and the values of capacitance and electron-transfer resistance of the material (R(et)) are calculated to be 13.74 pF and 388 kΩ, respectively. The presence of a single Debye peak in both the impedance and modulus vs frequency plots suggests an isotropic nature of the system, and the frequency dependent ac-conductivity suggests the presence of short-range translational and reorientational (localized) hopping of charge carriers at lower and higher frequency region.

Fluorescence resonance energy transfer from sulfonated graphene to riboflavin: a simple way to detect vitamin B2.

We have prepared sulfonated graphene (SG) by diazonium coupling technique and it has been characterized by UV-vis absorption spectroscopy, Raman spectroscopy, electron microscopy, energy-dispersive spectroscopy (EDS), EDS elemental mapping, X-ray photoelectron spectroscopy (XPS), and FTIR spectroscopy. The photoluminescence (PL) property of SG at different pH (pH 4, 7, and 9.2) has been investigated and SG shows highest PL-intensity and quantum yield at pH 4 compared to those at higher pH and that of GO at pH 4. Due to the strong overlap between the emission spectrum of SG and absorption spectrum of riboflavin (RF, vitamin B2) at pH 4, it has been tactfully used as donor for the fluorescence resonance energy transfer (FRET) process. However, graphene oxide (GO) does not exhibit any FRET with RF at an identical condition due to its much lower quantum yield. We have demonstrated a selective detection of vitamin B2 in presence of nucleic acid (DNA, RNA), protein (BSA), amino acid (Lysine) and other water-soluble vitamins (Becosules, Zevit capsules) based on the spontaneous FRET from PL-active SG (donor) to RF (acceptor). The calibration curve indicates excellent affirmation to detect vitamin B2 using FRET and it is superior to the ordinary fluorescence method of detecting RF in presence of different biomolecules.

Ethidium bromide-adsorbed graphene templates as a platform for preferential sensing of DNA.

Sulfonated graphene (SG) and graphene oxide (GO) are used as an ethidium bromide (EtBr, E) binding platform, to preferentially sense DNA (D) among the other biomolecules such as RNA (R), bovine serum albumin (BSA, P) and glucose (G) using spectroscopic techniques. EtBr loses its intrinsic fluorescence property after binding with SG. DNA can "turn on" the quenched fluorescence of an SG-EtBr hybrid to a greater extent compared to the RNA, BSA, and glucose. UV-vis absorption spectra and circular dichroism (CD) spectra also support the higher ability of DNA to release adsorbed EtBr from the SG surface in comparison to the above-mentioned biomolecules. Compared to GO-EtBr, the SG-EtBr hybrid is superior to preferentially sense DNA, as the enhancement of fluorescence intensity is 16 times in the later but it is 4.5 times in the former from their respective complexes. An analysis of Raman spectral data indicates that the interaction of EtBr in its adsorbed state on an SG template is greater with DNA than with RNA.