Shigellosis

Niyogi Swapan Kumar The Microbiological Society of Korea 2005 The journal of microbiology Vol.43 No.2

Shigellosis is a global human health problem. Four species of Shigella i.e. S. dysenteriae, S. flexneri, S. boydii and S. sonnei are able to cause the disease. These species are subdivided into serotypes on the basis of O-specific polysaccharide of the LPS. Shigella dysenteriae type 1 produces severe disease and may be associated with life-threatening complications. The symptoms of shigellosis include diarrhoea and/or dysentery with frequent mucoid bloody stools, abdominal cramps and tenesmus. Shigella spp. cause dysentery by invading the colonic mucosa. Shigella bacteria multiply within colonic epithelial cells, cause cell death and spread laterally to infect and kill adjacent epithelial cells, causing mucosal ulceration, inflammation and bleeding. Transmission usually occurs via contaminated food and water or through person-to-person contact. Laboratory diagnosis is made by culturing the stool samples using selective/differential agar media. Shigella spp. are highly fragile organism and considerable care must be exercised in collecting faecal specimens, transporting them to the laboratories and in using appropriate media for isolation. Antimicrobial agents are the mainstay of therapy of all cases of shigellosis. Due to the global emergence of drug resistance, the choice of antimicrobial agents for treating shigellosis is limited. Although single dose of norfloxacin and ciprofloxacin has been shown to be effective, they are currently less effective against S. dysenteriae type 1 infection. Newer quinolones, cephalosporin derivatives, and azithromycin are the drug of choice. However, fluoroquinolone-resistant S. dysenteriae type 1 infection have been reported. Currently, no vaccines against Shigella infection exist. Both live and subunit parenteral vaccine candidates are under development. Because immunity to Shigella is serotype-specific, the priority is to develop vaccine against S. dysenteriae type 1 and S. flexneri type 2a. Shigella species are important pathogens responsible for diarrhoeal diseases and dysentery occurring all over the world. The morbidity and mortality due to shigellosis are especially high among children in developing countries. A recent review of literature (KotIoff et al.,1999) concluded that, of the estimated 165 million cases of Shigella diarrhoea that occur annually, $99\%$ occur in developing countries, and in developing countries $69\%$ of episodes occur in children under five years of age. Moreover, of the ca.1.1 million deaths attributed to Shigella infections in developing countries, $60\%$ of deaths occur in the under-five age group. Travellers from developed to developing regions and soldiers serving under field conditions are also at an increased risk to develop shigellosis.

Primary hepatic tuberculosis

Devayani Niyogi,Mahesh Goel,Rajesh S Shinde,Shraddha Patkar 한국간담췌외과학회 2019 Annals of hepato-biliary-pancreatic surgery Vol.23 No.1

Primary hepatic tuberculosis is a rare entity and can closely mimic malignancy with respect to clinical presentation and imaging features. We identified five patients at a high volume tertiary care cancer center, whose clinical features and imaging closely mimicked primary liver malignancy or metastases but final histopathology was suggestive of hepatic tuberculosis. Three patients underwent a surgical resection whereas two were diagnosed on a biopsy. Anti-tuberculosis therapy was started for all the patients which was well tolerated. All patients are doing well at the time of the last follow up. This case series stresses the importance of having a high index of suspicion and preoperative biopsy in cases where imaging features are equivocal.

Shigellosis

Swapan Kumar Niyogi 한국미생물학회 2005 The journal of microbiology Vol.43 No.2

Analysis of normal electrocardiograms of Jamunapari goats

N.H.Mohan,D.Niyogi,H.N.Singh 대한수의학회 2005 Journal of Veterinary Science Vol.6 No.4

In the present study, the normal electrocardiographic (ECG) values in the adult male Jamunapari breed of the goats were described. The mean heart rate in the goats was 127 ± 3.46 per minute and ranged 107 and 168. The amplitudes and duration of various waveforms of ECG for six standard limb leads (I, II, III, aVL, aVR and aVF) were estimated. The overall P, QRS and T amplitudes (millivolts) were 0.065 ± 0.01, 0.47 ± 0.06 and 0.20 ± 0.014 respectively. The duration (seconds) of these wave forms were 0.042 ± 0.005, 0.033 ± 0.002 and 0.10 ± 0.014, respectively. The P-R interval and R-R intervals ranged between 0.06-0.14 and 0.40-0.58 respectively. The average Q-T interval was 0.24 ± 0.01 second, indicating the time for which the caprine ventricle remained depolarized. The corrected QT interval was also calculated which was found to vary from 0.24 to 0.57. The mean frontal plane vectors for the wave forms P, QRS and T wave forms were +49.99 ± 6.02, +37.34 ± 4.05 and +52.26 ± 6.79 degrees respectively.

Zeaxanthin radical cation formation in minor light-harvesting complexes of higher plant antenna.

Avenson, Thomas J,Ahn, Tae Kyu,Zigmantas, Donatas,Niyogi, Krishna K,Li, Zhirong,Ballottari, Matteo,Bassi, Roberto,Fleming, Graham R American Society for Biochemistry and Molecular Bi 2008 The Journal of biological chemistry Vol.283 No.6

<P>Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5% of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N) <==> LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions.</P>

A finite element based approach to observe hydrodynamic pressure in reservoir adjacent to concrete gravity dam

Santosh Kumar, Das,Kalyan Kumar, Mandal,Arup Guha, Niyogi Techno-Press 2022 Ocean systems engineering Vol.12 No.4

This paper deals with the study of hydrodynamic pressure in reservoir adjacent to the concrete gravity dam subjected to dynamic excitation. Widely famous finite element method is used to discretize the reservoir domain for modelling purpose. Pressure is considered as nodal variable following Eulerian approach. A suitable nonreflecting boundary condition is applied at truncated face of reservoir to make the infinite reservoir to finite one for saving the computational cost. Thorough studies have been done on generation of hydrodynamic pressure in reservoir with variation of different geometrical properties. Velocity profile and hydrodynamic pressure are observed due to harmonic excitation for variation of inclination angle of dam reservoir interface. Effect of bottom slope angle and inclined length of reservoir bottom on hydrodynamic pressure coefficient of reservoir are also observed. There is significant increase in hydrodynamic pressure and distinct changes in velocity profile of reservoir are noticeable for change in inclination angle of dam reservoir interface. Change of bottom slope and inclined length of reservoir bottom are also governing factor for variation of hydrodynamic pressure in reservoir subjected to dynamic excitation.

Intraoperative Nerve Monitoring during Minimally Invasive Esophagectomy and 3-Field Lymphadenectomy: Safety, Efficacy, and Feasibility

Srinivas Kodaganur Gopinath,Sabita Jiwnani,Parthiban Valiyuthan,Swapnil Parab,Devayani Niyogi,Virendrakumar Tiwari,C. S. Pramesh 대한심장혈관흉부외과학회 2023 Journal of Chest Surgery (J Chest Surg) Vol.56 No.5

Background: The objective of this study was to demonstrate the safety, efficacy, and feasibility of intraoperative monitoring of the recurrent laryngeal nerves during thoracoscopic and robotic 3-field esophagectomy. Methods: This retrospective analysis details our initial experience using intraoperative nerve monitoring (IONM) during minimally invasive 3-field esophagectomy. Data were obtained from a prospectively maintained database and electronic medical records. The study included all patients who underwent minimally invasive (video-assisted thoracic surgery/robotic) transthoracic esophagectomy with neck anastomosis. The patients were divided into those who underwent IONM during the study period and a historical cohort who underwent 3-field esophagectomy without IONM at the same institution. Appropriate statistical tests were used to compare the 2 groups. Results: Twenty-four patients underwent nerve monitoring during minimally invasive 3-field esophagectomy. Of these, 15 patients underwent thoraco-laparoscopic operation, while 9 received a robot-assisted procedure. In the immediate postoperative period, 8 of 24 patients (33.3%) experienced vocal cord paralysis. Relative to a historical cohort from the same institution, who were treated with surgery without nerve monitoring in the preceding 5 years, a 26% reduction was observed in the nerve paralysis rate (p=0.08). On follow-up, 6 of the 8 patients with vocal cord paralysis reported a return to normal vocal function. Additionally, patients who underwent IONM exhibited a higher nodal yield and a decreased frequency of tracheostomy and bronchoscopy. Conclusion: The use of IONM during minimally invasive 3-field esophagectomy is safe and feasible. This technique has the potential to decrease the incidence of recurrent nerve palsy and increase nodal yield.

Investigating energy partitioning during photosynthesis using an expanded quantum yield convention

Ahn, T.K.,Avenson, T.J.,Peers, G.,Li, Z.,Dall'Osto, L.,Bassi, R.,Niyogi, K.K.,Fleming, G.R. Elsevier Science Publishers [etc.] 2009 Chemical physics Vol.357 No.1

In higher plants, regulation of excess absorbed light is essential for their survival and fitness, as it enables avoidance of a build up of singlet oxygen and other reactive oxygen species. Regulation processes (known as non-photochemical quenching; NPQ) can be monitored by steady-state fluorescence on intact plant leaves. Pulse amplitude modulated (PAM) measurements of chlorophyll a fluorescence have been used for over 20 years to evaluate the amount of NPQ and photochemistry (PC). Recently, a quantum yield representation of NPQ (Φ<SUB>NPQ</SUB>), which incorporates a variable fraction of open reaction centers, was proposed by Hendrickson et al. [L. Hendrickson, R.T. Furbank, W.S. Chow, Photosynth. Res. 82 (2004) 73]. In this work we extend the quantum yield approach to describe the yields of reversible energy-dependent quenching (Φ<SUB>qE</SUB>), state transitions to balance PC between photosystems II and I (Φ<SUB>qT</SUB>), and photoinhibition quenching associated with damaged reaction centers (Φ<SUB>qI</SUB>). We showed the additivity of the various quantum yield components of NPQ through experiments on wild-type and npq1 strains of Arabidopsis thaliana. The quantum yield approach enables comparison of Φ<SUB>qE</SUB> with data from a variety of techniques used to investigate the mechanism of qE. We showed that Φ<SUB>qE</SUB> for a series of A. thaliana genotypes scales linearly with the magnitude of zeaxanthin cation formation, suggesting that charge-transfer quenching is largely responsible for qE in plants.

Classification of Hybrid and Altered Vibrio cholerae Strains by CTX Prophage and RS1 Element Structure

Je Hee Lee,Seon Young Choi,Yoon-Seong Jeon,Hye Ri Lee,김은진,Binh Minh Nguyen,Nguyen Tran Hien,M. Ansaruzzaman,M. Sirajul Islam,Nurul A. Bhuiyan,S.K. Niyogi,B.L. Sarkar,G. Balakrish Nair,Dae Shick Kim,An 한국미생물학회 2009 The journal of microbiology Vol.47 No.6

Analysis of the CTX prophage and RS1 element in hybrid and altered Vibrio cholera O1 strains showed two classifiable groups. Group I strains contain a tandem repeat of classical CTX prophage on the small chromosome. Strains in this group either contain no element(s) or an additional CTX prophage or RS1 element(s) on the large chromosome. Group II strains harbor RS1 and CTX prophage, which has an El Tor type rstR and classical ctxB on the large chromosome.

Evidence for several waves of global transmission in the seventh cholera pandemic

Mutreja, Ankur,Kim, Dong Wook,Thomson, Nicholas R.,Connor, Thomas R.,Lee, Je Hee,Kariuki, Samuel,Croucher, Nicholas J.,Choi, Seon Young,Harris, Simon R.,Lebens, Michael,Niyogi, Swapan Kumar,Kim, Eun J Nature Publishing Group, a division of Macmillan P 2011 Nature Vol.477 No.7365

Vibrio cholerae is a globally important pathogen that is endemic in many areas of the world and causes 3??5??million reported cases of cholera every year. Historically, there have been seven acknowledged cholera pandemics; recent outbreaks in Zimbabwe and Haiti are included in the seventh and ongoing pandemic. Only isolates in serogroup O1 (consisting of two biotypes known as ??classical?? and ??El Tor??) and the derivative O139 (refs 2, 3) can cause epidemic cholera. It is believed that the first six cholera pandemics were caused by the classical biotype, but El Tor has subsequently spread globally and replaced the classical biotype in the current pandemic. Detailed molecular epidemiological mapping of cholera has been compromised by a reliance on sub-genomic regions such as mobile elements to infer relationships, making El Tor isolates associated with the seventh pandemic seem superficially diverse. To understand the underlying phylogeny of the lineage responsible for the current pandemic, we identified high-resolution markers (single nucleotide polymorphisms; SNPs) in 154 whole-genome sequences of globally and temporally representative V.??cholerae isolates. Using this phylogeny, we show here that the seventh pandemic has spread from the Bay of Bengal in at least three independent but overlapping waves with a common ancestor in the 1950s, and identify several transcontinental transmission events. Additionally, we show how the acquisition of the SXT family of antibiotic resistance elements has shaped pandemic spread, and show that this family was first acquired at least ten years before its discovery in V.??cholerae.