Hemosuccus Pancreaticus

Hemosuccus pancreaticus (HP) defined as bleeding into the pancreatic duct was first described in 1931 by Lower and Farell. HP also popularly known as wirsungorrhaghia and pseudohemobilia is a rare cause of gastrointestinal bleed. The unfamiliarity of this condition makes HP a diagnostic challenge. HP should be considered in patients with chronic pancreatitis presenting with acute gastrointestinal bleeding. The diagnosis is usually confirmed with a computerized tomography (CT) scan of the abdomen. A mesenteric angiogram with coil embolization can be performed to arrest the bleeding. The literature on this condition is restricted to case reports, case series and retrospective studies. We describe a case of HP in a patient with gastrointestinal bleeding and take this opportunity to review the literature outlining the diagnosis and management of HP.

Variations in antibiotic use across India: multi-centre study through Global Point Prevalence survey

The aim of the study was to assess antimicrobial prescribing patterns, and variation in practice, in India. A point prevalence survey (PPS) was conducted in October to December 2017 in 16 tertiary care hospitals across India. The survey included all inpatients receiving an antimicrobial on the day of PPS and collected data were analysed using a web-based application of the University of Antwerp. In all, 1750 patients were surveyed, of whom 1005 were receiving a total of 1578 antimicrobials. Among the antimicrobials prescribed, 26.87% were for community-acquired infections; 19.20% for hospital-acquired infections; 17.24% for medical prophylaxis; 28.70% for surgical prophylaxis; and 7.99% for other or undetermined reasons. Antibiotic prescribing quality indicators, such as reason in notes and post-prescription review score, were low. This PPS showed widespread antibiotic usage, underlining the need for antibiotic stewardship to promote evidence-based practice.

A New Lupane Triterpenoid from Peganum Harmala

A new lupane triterpenoid, 27-hydroxylup-20(29)-en-27-O-(3,4-dimethoxycinnamoyl)-28-oic acid methyl ester (1) was isolated from the seeds of Peganum harmala. The structure was determined from extensive 1D- and 2D- NMR spectroscopic data.

Transoral endoscopic thyroidectomy using vestibular approach: A single center experience

Background:

Thyroid Natural Orifice Transluminal Endoscopic Surgery (NOTES) or transoral endoscopic thyroidectomy using vestibular approach is a recent advance embraced by the surgical community because of its potential for a scar-free thyroidectomy. In this article, we present our initial experience with this technique.

Materials and Methods:

We used a three-port technique through the oral vestibule, one 10 mm port for the laparoscope and two additional 5 mm ports for the endoscopic instruments required. The carbon dioxide insufflation pressure was set at 12 mm of Hg. Anterior cervical subplatysmal space was created from the oral vestibule down to the sternal notch, and the thyroidectomy was done using conventional laparoscopic instruments and a harmonic scalpel.

Results:

From May 2016 to December 2017, we have performed ten such procedures in the Department of General Surgery in our hospital, which is a tertiary referral center. Six patients had solitary thyroid nodules, for which a hemi-thyroidectomy was done. Four patients had multi-nodular goiter and total thyroidectomy or near-total thyroidectomy was done. The preoperative fine-needle aspiration cytology (FNAC) was suggestive of Bethesda class 2 lesions in all the patients with multinodular goiter and in five of the six patients with solitary nodular goiter. Only one patient with solitary nodular goiter had a Bethesda class 3 lesion on FNAC. The final histopathological report of the specimen was benign, either colloid goiter, or degenerative nodule in all cases of multinodular goiter and in four cases of solitary thyroid nodule. In one Bethesda class 2 solitary nodule, the histopathological report was suggestive of follicular carcinoma; in the Bethesda class 3 solitary nodule, the histopathological report was suggestive of follicular variant of papillary carcinoma. No complication such as temporary or permanent vocal cord paralysis, hypoparathyroidism, subcutaneous emphysema, pneumomediastinum, tracheal injury, esophageal injury, mental nerve palsy, or surgical site infection was found postoperatively. However, two patients developed small hematomas in the midline.

Conclusion:

Transoral endoscopic thyroidectomy is a safe, feasible, and minimally invasive technique with excellent cosmetic results.

Identifying avoidable switchboard delays in England's NHS hospitals: phase one of the national SWITCH project

BACKGROUND

Inter-hospital communication frequently requires mediation via a switchboard. Identifying and eliminating switchboard inefficiencies may improve patient care.

METHODS

All 175 acute hospital switchboards in England were contacted six times. Call contents and duration were recorded. No clinician calls or bleeps were connected.

RESULTS

The mean delay before contacting a switchboard operative was 55±46 seconds. 115 hospitals (66%) used automated switchboards; 34 of these (30%) had infection control messages. Robot operators introduced an additional 40 second delay versus humans (mean 70.3±28 versus 29.8±23 seconds, p<0.0001). Multivariate analysis identified robot operators (HR 5.1, p<0.0001) and infection control messages (HR 2.9, p=0.003) as predictors of delays over 60 seconds.

CONCLUSIONS

There are significant avoidable delays in contacting switchboard operatives across England. Quality improvement is underway.

Purification, Characterization and in vitro Evaluation of Polymyxin A From Paenibacillus dendritiformis: An Underexplored Member of the Polymyxin Family

Nosocomial infections caused by antibiotic-resistant Gram-negative pathogens are of grave concern today. Polymyxins are considered as the last resorts of therapy to treat these multi-drug resistant (MDR) bacteria. But their associated nephrotoxicity and neurotoxicity calls for the development of safer polymyxin therapy until novel and less toxic antibiotics are discovered. No other polymyxin molecule except polymyxin B and E (colistin) is explored thoroughly in literature to demonstrate its clinical relevance. In the present study, we have isolated two antimicrobial compounds named P1 and P2 from the soil isolate Paenibacillus dendritiformis strain PV3-16, which we later identified as polymyxin A₂ and A₁ respectively. We tested their minimum inhibitory concentrations (MICs) against MDR clinical isolates, performed membrane permeabilization assays and determined their interaction with lipopolysaccharide (LPS). Finally, we studied their toxicity against human Leukemic monocyte cell line (THP-1) and embryonic kidney cell line (HEK 293). Both compounds displayed equal efficacy when compared with standard polymyxins. P1 was 2-4 fold more active in most of the clinical strains tested. Moreover, P1 showed higher affinity toward LPS. In cytotoxicity studies, P1 had IC₅₀ value (>1000 μg/ml) similar to colistin against HEK cells but immune cells, i.e., THP-1 cell lines were more sensitive to polymyxins. P1 showed less toxicity in THP-1 cell line than all other polymyxins checked. To sum up, P1 (polymyxin A₂) possessed better efficacy than polymyxin B and E and had least toxicity to immune cells. Since polymyxin A was not investigated thoroughly, we performed the comprehensive in vitro assessment of this molecule. Moreover, this is the first report of isolation and characterization of polymyxin A from P. dendritiformis. This compound should be further investigated for its in vivo efficacy and toxicity to develop it as a drug candidate.

Severe hypocalcemia mimicking acute inferior ST-segment elevation myocardial infarction

We report the case of a 52-year-old gentleman, admitted to the medical intensive care unit with multiple organ system dysfunction due to acute severe pancreatitis. He was found to have severe hypocalcemia, bradycardia and an electrocardiogram (EKG) showing ST-segment elevation in infero-lateral leads. The patient was treated with intravenous calcium gluconate with prompt improvement of heart rate and reversal of EKG changes. Subsequent evaluation for myocardial ischemia was negative. We believe the EKG changes mimicking acute ST-segment elevation myocardial infarction were due to severe hypocalcemia. To our knowledge this is very rare occurrence.

Rv3272 encodes a novel Family III CoA transferase that alters the cell wall lipid profile and protects mycobacteria from acidic and oxidative stress

The availability of complete genome sequence of Mycobacterium tuberculosis has provided an important tool to understand the mycobacterial biology with respect to host-pathogen interaction, which is an unmet need of the hour owing to continuous increasing drug resistance. Hypothetical proteins are often an overlooked pool though half the genome encodes for such proteins of unknown function that could potentially play vital roles in mycobacterial biology. In this context, we report the structural and functional characterization of the hypothetical protein Rv3272. Sequence analysis classifies Rv3272 as a Family III CoA transferase with the classical two domain structure and conserved Aspartate residue (D175). The crystal structure of the wild type protein (2.2 Å) demonstrated the associated inter-locked dimer while that of the D175A mutant co-crystallized with octanoyl-CoA demonstrated relative movement between the two domains. Isothermal titration calorimetry studies indicate that Rv3272 binds to fatty acyl-CoAs of varying carbon chain lengths, with palmitoyl-CoA (C16:0) exhibiting maximum affinity. To determine the functional relevance of Rv3272 in mycobacterial biology, we ectopically expressed Rv3272 in M. smegmatis and assessed that its expression encodes significant alteration in cell surface with marked differences in triacylglycerol accumulation. Additionally, Rv3272 expression protects mycobacteria from acidic, oxidative and antibiotic stress under in vitro conditions. Taken together, these studies indicate a significant role for Rv3272 in host-pathogen interaction.

Structural and Biophysical Characterization of Rab5a from Leishmania Donovani

Leishmania donovani possess two isoforms of Rab5 (Rab5a and Rab5b), which are involved in fluid phase and receptor-mediated endocytosis, respectively. We have characterized the solution structure and dynamics of a stabilized truncated LdRab5a mutant. For the purpose of NMR structure determination, protein stability was enhanced by systematically introducing various deletions and mutations. Deletion of hypervariable C-terminal and the 20 residues LdRab5a specific insert slightly enhanced the stability, which was further improved by C107S mutation. The final construct, truncated LdRab5a with C107S mutation, was found to be stable for longer durations at higher concentration, with an increase in melting temperature by 10°C. Solution structure of truncated LdRab5a shows the characteristic GTPase fold having nucleotide and effector binding sites. Orientation of switch I and switch II regions match well with that of guanosine 5'-(β, γ-imido)triphosphate (GppNHp)-bound human Rab5a, indicating that the truncated LdRab5a attains the canonical GTP bound state. However, the backbone dynamics of the P-loop, switch I, and switch II regions were slower than that observed for guanosine 5'-(β, γ-imido)triphosphate (GMPPNP)-bound H-Ras. This dynamic profile may further complement the residue-specific complementarity in determining the specificity of interaction with the effectors. In parallel, biophysical investigations revealed the urea induced unfolding of truncated LdRab5a to be a four-state process that involved two intermediates, I1 and I2. The maximal 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (Bis-ANS) binding was observed for I2 state, which was inferred to have molten globule like characteristics. Overall, the strategy presented would have significant impact for studying other Rab and small GTPase proteins by NMR spectroscopy.

Facile synthesis of WS2 nanotubes by sulfurization of tungsten thin films: formation mechanism, and structural and optical properties

While 2D layers of WS2 have been extensively studied, there are very few investigations of WS2 nanotubes. These have usually been grown via a 2-step process involving a WO3-x intermediate. We report a simple process for the synthesis of WS2 nanotubes via the sulfurization of tungsten films under appropriate conditions and present details of their structural and optical properties that help elucidate the formation mechanism. Electron-beam evaporated films of tungsten are sulfurized under flowing N2 gas at 950-1000 °C temperature under atmospheric pressure to obtain WS2 nanotubes. High-resolution scanning and transmission electron microscopy studies show that 2D WS2 flakes curl up and wrap around themselves to form nanotubes. Interlayer spacings in both 'a' and 'c' directions are slightly smaller than the corresponding values in bulk and thin film WS2. Micro-photoluminescence and micro-transmission studies show a resonance that seems intrinsic to the WS2 nanotubes since it cannot be related to the known optical characteristics of WS2 flakes.

Antibacterial properties of human beta defensin-3 derivative: CHRG01

Antibiotic resistance in bacteria is a major health concern. Antimicrobial peptides (AMPs) are a class of peptides that are efficient in killing most microbes yet development of resistance to AMPs is rare. However, complex secondary and tertiary structures and difficulties in isolating AMPs have limited their use as antibiotics. It has been demonstrated earlier that small peptides derived from human β defensin-3 (HBD-3) also show antibacterial activity. Here, we perform a detailed characterization of the antibacterial activity of one such derivative: CHRG01. While HBD-3 has 45 amino acids with three disulphide bonds and a β-sheet folded structure, CHRG01 has only 14 amino acids with the cysteine residues replaced by serine. The antibacterial nature of CHRG01 was studied using scanning electron microscopy (SEM), confocal microscopy, circular dichroism (CD) and small-angle X-ray scattering (SAXS). CD data show that CHRG01 is random coiled in solution. SEM and confocal studies show that the mode of action of CHRG01 is pore forming. SAXS studies show that CHRG01 induces a negative Gaussian curvature, the type of curvature needed for pore formation. The above results show that CHRG01, a small peptide without any complex structure, is capable of killing bacteria by permeabilizing their outer membranes.

Valley-contrasting optics of interlayer excitons in Mo- and W-based bulk transition metal dichalcogenides

Recently, spatially indirect ("interlayer") excitons have been discovered in bulk 2H-MoTe2. They are theoretically predicted to exist in other Mo-based transition metal dichalcogenides (TMDCs) and are expected to be present in W-based TMDCs as well. We investigate interlayer excitons (XIL) in bulk 2H-MoSe2 and 2H-WSe2 using valley-resolved magneto-reflectance spectroscopy under high magnetic fields of up to 29 T combined with ab initio GW-BSE calculations. In the experiments, we observe interlayer excitons in MoSe2, while their signature is surprisingly absent in WSe2. In the calculations, we find that interlayer excitons exist in both Mo- and W-based TMDCs. However, their energetic positions and their oscillator strengths are remarkably different. In Mo-based compounds, the interlayer exciton resonance XIL is clearly separated from the intralayer exciton X1sA and has a high amplitude. In contrast, in W-based compounds, XIL is close in energy to the intralayer A exciton X1sA and possesses a small oscillator strength, which explains its absence in the experimental data of WSe2. Our combined experimental and theoretical observations demonstrate that interlayer excitons can gain substantial oscillator strength by mixing with intralayer states and hence pave the way for exploring interlayer exciton physics in Mo-based bulk transition metal dichalcogenides.