A Direct Link Implicating Loss of SLC26A6 to Gut Microbial Dysbiosis, Compromised Barrier Integrity and Inflammation

BACKGROUND

Putative anion transporter-1 (PAT1, SLC26A6) plays a key role in intestinal oxalate and bicarbonate secretion. PAT1 knockout (PKO) mice exhibit hyperoxaluria and nephrolithiasis. Notably, diseases such as inflammatory bowel diseases (IBD) are also associated with higher risk of hyperoxaluria and nephrolithiasis. However, the potential role of PAT1 deficiency in gut barrier integrity and susceptibility to colitis is currently elusive.

METHODS

Age-matched PKO and wild-type (WT) littermates were administered 3.5%-DSS in drinking water for 6 days. Ileum and colon of control and treated mice were harvested. mRNA and protein expression of tight junction (TJ) proteins were determined by RT-PCR and western blotting. Severity of inflammation was assessed by measuring diarrheal phenotype, cytokine expression and H&E staining. Gut microbiome and associated metabolome were analyzed by 16S rRNA sequencing and mass spectrometry, respectively.

RESULTS

PKO mice exhibited significantly higher loss of body weight, gut permeability, colonic inflammation, and diarrhea in response to DSS treatment. Additionally, PKO mice showed microbial dysbiosis and significantly reduced levels of butyrate and butyrate-producing microbes compared to controls. Cohousing WT and PKO mice for 4 weeks resulted in PKO-like signatures on the expression of TJ proteins in the colon of WT mice.

CONCLUSION

Our data demonstrate that loss of PAT1 disrupts gut microbiome and related metabolites, decreases gut barrier integrity, and increases host susceptibility to intestinal inflammation. These findings, thus, highlight a novel role of the oxalate transporter PAT1 in promoting gut barrier integrity and its deficiency appears to contribute to the pathogenesis of IBD.

Ion Transport Basis of Diarrhea, Paneth Cell Metaplasia, and Upregulation of Mechanosensory Pathway in Anti-CD40 Colitis Mice

BACKGROUND

Anti-Cluster of differentiation (CD)-40-induced colitis, driven by innate inflammatory responses in the intestine, is a potent animal model exhibiting IBD pathophysiology including diarrhea. However, the ion transport basis of diarrhea and some key mucosal pathways (Paneth cells, stem cell niche, and mechanosensory) in this model have not been investigated.

METHODS

Mucosal scrapings and intestinal tissue from control and CD40 antibody (150 µg) treated Rag2-/- mice were examined for gut inflammation, Paneth cell numbers, expression of key transporters, tight/adherens junction proteins, stem cell niche, and mechanosensory pathway via hematoxylin and eosin staining, quantitative polymerase chain reaction, and western blotting.

RESULTS

Compared with control, anti-CD40 antibody treatment resulted in a significant loss of body weight (P < .05) and diarrhea at day 3 postinjection. Distal colonic tissues of anti-CD40 mice exhibited increased inflammatory infiltrates, higher claudin-2 expression, and appearance of Paneth cell-like structures indicative of Paneth cell metaplasia. Significantly reduced expression (P < .005) of downregulated in adenoma (key Cl- transporter), P-glycoprotein/multidrug resistantance-1 (MDR1, xenobiotic transporter), and adherens junction protein E-cadherin (~2-fold P < .05) was also observed in the colon of anti-CD40 colitis mice. Interestingly, there were also marked alterations in the stem cell markers and upregulation of the mechanosensory YAP-TAZ pathway, suggesting the activation of alternate regeneration pathway post-tissue injury in this model.

CONCLUSION

Our data demonstrate that the anti-CD40 colitis model shows key features of IBD observed in the human disease, hence making it a suitable model to investigate the pathophysiology of ulcerative colitis (UC).

Need for enrichment of lutetium isotope and design of a laser based separator module

Lutetium-177 radio-pharmaceutical has become an important theranostic candidate in cancer treatment. Its availability from bench-to-bed requires strategic implementation of isotope-enrichment, neutron-irradiation and radio-chemical techniques. In this paper, the need for enrichment of lutetium-176 is emphasized by estimating specific activity of lutetium-177 as a function of enrichment percentage for typical neutron flux available at Dhruva reactor, India. A novel Atomic Vapour Laser Isotope Separation (AVLIS) module for lutetium-176 enrichment is designed to meet the above requirement. The paper documents its characteristics and production estimates. The design is carried out after critical assessment and evaluation of available AVLIS-infrastructure in the country. Outline of lutetium-177 enrichment, capable of producing non-carrier-added lutetium is also provided. This work concludes that India has taken a step forward towards self-reliance (Atmanirbhar Bharat) in securing the supply chain of lutetium-177.

Loss of SLC26A3 Results in Colonic Mucosal Immune Dysregulation via Epithelial-Immune Cell Crosstalk

BACKGROUND & AIMS

Down-regulation of chloride transporter SLC26A3 or down-regulated in adenoma (DRA) in colonocytes has recently been linked to the pathogenesis of ulcerative colitis (UC). Because exaggerated immune responses are one of the hallmarks of UC, these current studies were undertaken to define the mechanisms by which loss of DRA relays signals to immune cells to increase susceptibility to inflammation.

METHODS

NanoString Immunology Panel, fluorescence assisted cell sorting, immunoblotting, immunofluorescence, and quantitative real-time polymerase chain reaction assays were used in wild-type and DRA knockout (KO) mice. Interleukin (IL)-33 blocking was used to determine specific changes in immune cells and co-housing/broad spectrum antibiotics administration, and ex vivo studies in colonoids were conducted to rule out the involvement of microbiota. Colonoid-derived monolayers from healthy and UC patient biopsies were analyzed for translatability.

RESULTS

There was a marked induction of Th2 (>2-fold), CD4⁺ Th2 cells (∼8-fold), RORγt⁺ Th17, and FOXP3⁺ regulatory T cells (Tregs). DRA KO colons also exhibited a robust induction of IL-33 (>8-fold). In vivo studies using blocking of IL-33 established that T2 immune dysregulation (alterations in ILC2, Th2, and GATA3⁺ iTregs) in response to loss of DRA was due to altered epithelial-immune cell crosstalk via IL-33.

CONCLUSIONS

Loss of DRA in colonocytes triggers the release of IL-33 to drive a type 2 immune response. These observations emphasize the critical importance of DRA in mucosal immune homeostasis and its implications in the pathogenesis of UC.

Randomized control trial evaluating the use of a shared decision-making aid for older ventral hernia patients in the Geriatric Assessment and Medical Preoperative Screening (GrAMPS) Program

PURPOSE

Shared decision making (SDM) is ideally suited to abdominal wall surgery in older adults given the breadth of decision making required by the hernia surgeon and the impact on quality of life (QOL) by various treatment options. Given the paucity of literature surrounding SDM in hernia patients, the feasibility of a novel, formalized SDM aid/tool was evaluated in a pilot randomized trial.

METHODS

Patients 60 years or older with a diagnosed ventral hernia were prospectively randomized at an academic hernia center. In the experimental arm, a novel SDM tool, based on the SHARE Approach, guided the consultation. Previously validated SDM assessments and patient's hernia knowledge retention was measured.

RESULTS

Eighteen (18) patients were randomized (9 control and 9 experimental). Cohorts were well matched in age (p = 0.51), comorbidities (Charlson Comorbidity Score: p = 0.43) and frailty (mFI-11: p = 0.19; Risk Analysis Index: p = 0.33). Consultation time was 11 min longer in the experimental cohort (p < 0.01). There was a trend towards better Decisional Conflict Scores in the experimental group (p = 0.25) and the experimental cohort had improved post-visit retained hernia knowledge (p < 0.01). All patients in the experimental arm (100%) enjoyed working through the SDM aid/tool and felt it was a worthwhile exercise.

CONCLUSION

Incorporating a formalized SDM tool into a busy hernia surgical practice is feasible and well received by patients. In addition, early results suggest it improves retention of basic hernia knowledge and may reduce patient's decisional conflict. Next steps include condensing the SDM tool to enhance efficiency within the clinic and beginning a large, randomized control trial.

Phenomenological Constraints on the Transport Properties of QCD Matter with Data-Driven Model Averaging

Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150-350  MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma's final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities.

Recurrent aplastic anemia with donor-type aplasia: A rare occurrence in the Indian subcontinent

Donor-type aplasia (DTA) is a condition where an individual continues to be aplastic even after a successful engraftment of a hematopoeitic stem cell transplant with a majority of donor type cells in the bone marrow. This entity has been seen with varying frequency around the world, especially in Southeast Asia. However, its incidence in the Indian subcontinent remains fairly low. Here is a case of a 17-year-old child with DTA who had a 89% population of donor cells after a successful transplant and presented with recurrent severe aplastic anemia later. The patient eventually succumbed to his condition before a second transplant could be performed. The awareness about the seriousness of this relatively rare condition, therefore, needs to be emphasized.

A combinational approach to restore cytokine balance and to inhibit virus growth may promote patient recovery in severe COVID-19 cases

The COVID-19 pandemic has led to twin public health and economic crises around the world. Not only has it cost hundreds of thousands of lives but also severely impacted livelihoods and placed enormous strain on community healthcare and welfare services. In this review, we explore the events associated with SARS-CoV-2 pathogenesis and host immunopathological reactivity due to the clinical manifestations of this coronavirus infection. We discuss that the metallopeptidase enzyme ADAM17, also known as tumor necrosis factor-α-converting enzyme, TACE, is responsible for shedding of angiotensin-converting enzyme 2 and membrane-bound interleukin (IL)-6 receptor. This leads to elevated pro-inflammatory responses that result in cytokine storm syndrome. We argue that cytokine balance may be restored by recovering an IL-6 trans-signaling neutralizing buffer system through the mediation of recombinant soluble glycoprotein 130 and recombinant ADAM17/TACE prodomain inhibitor. This cytokine restoration, possibly combined with inhibition of SARS-CoV-2 entry as well as replication and coagulopathy, could be introduced as a novel approach to treat patients with severe COVID-19. In cases of co-morbidity, therapies related to the management of associated disease conditions could ameliorate those clinical manifestations.

Decoding the enigma of antiviral crisis: Does one target molecule regulate all?

•

IL-6 class switching provides regulation over pro- and anti-inflammatory responses.

•

Unregulated IL-6 trans-signaling promotes uncontrolled pro-inflammatory responses.

•

ADAM-17 regulates class switching between IL-6 trans- and classical-signaling.

•

Selective ADAM-17 blocking restricts overexpression of pro-inflammatory cytokines.

•

ADAM-17 may be an antiviral drug target to reduce immunopathology disease severity.

Disease fatality associated with Ebola, SARS-CoV and dengue infections in humans is attributed to a cytokine storm that is triggered by excessive pro-inflammatory responses. Interleukin (IL)-6 acts as a mediator between pro- and anti-inflammatory reactivity by initiating trans- and classical-signaling, respectively. Hence, IL-6 is assumed to provide a target for a broad range of antiviral agents. Available immunosuppressive antivirals are directed to control an often exaggerated pro-inflammatory response that gives rise to complex clinical conditions such as lymphocytopenia. It is known that IL-6, via its soluble receptor (sIL-6R), initiates a pro-inflammatory response while an anti-inflammatory response is triggered by the membrane-bound IL-6 receptor (IL-6R). Future antivirals should thus aim to target the mechanism that regulates switching between IL-6 trans- and classical-signaling. In this review, we propose that the tumour necrosis factor-α converting enzyme ADAM-17 could be the master molecule involved in regulating IL-6 class switching and through this in controlling pro- and anti-inflammatory responses to viral antigenic stimuli. Therefore, ADAM-17 should be considered as a potential target molecule for novel antiviral drug discovery that would regulate host reactivity to infection and thereby limit or prevent fatal outcomes.

The use of Vicryl mesh in a porcine model to assess its safety as an adjunct to posterior fascial closure during retromuscular mesh placement

BACKGROUND

Posterior component separation has become a common approach to complex abdominal wall reconstructions. This technique includes creation of an extraperitoneal retromuscular space for subsequent large synthetic mesh reinforcement. In certain cases, when complete restoration of "posterior" layer is precluded by significant tissue loss/damage, one proposed strategy is to replace the posterior fascia with an absorbable synthetic polyglactin (Vicryl) mesh. However, the safety of this strategy to prevent mesh-related visceral complication is unknown. Herein, we aimed to characterize mesh-viscera adhesion profiles and host tissue response of synthetic mesh either exposed directly to the viscera, or protected with Vicryl mesh.

METHODS

Using adult Yorkshire pigs, 5 × 5 cm pieces of mesh were secured to the intact peritoneum in each of the four quadrants (n = 6 pigs, 24 mesh samples). The study groups were Vicryl (V), Marlex (M), Softmesh (S), Marlex + Vicryl construct (MV), Softmesh + Vicryl construct (SV). The self-made composite meshes were then implanted with the Vicryl side facing the exposed viscera. The pigs were survived for 60 days. At necropsy, grossly, the extent and tenacity of visceral adhesions were evaluated using established scales. Histologically, all specimens for fibrous encapsulation on the visceral surface of the mesh were reviewed by an experienced pathologist blind to meshes used.

RESULTS

At necropsy, all Vicryl meshes were completely resorbed. The mean adhesion and tenacity scores for M and MV were 1.8 and 1.1 (P > 0.05), 2.0 and 1.5 (P > 0.05), respectively; while the mean adhesion extent scores and tenacity scores for S and SV were 2.0 and 1.2 (P > 0.05), 2.0 and 1.7 (P > 0.05). No significant difference in adhesion extent and tenacity was observed between Synthetic and Vicryl composite mesh groups. Histologically, Marlex + Vicryl mesh and Softmesh + Vicryl mesh constructs had thicker fibrous capsules than the corresponding unprotected Marlex and Soft mesh implants. Furthermore, visceral adhesions in the composite groups were noted to be to the fibrous capsule and not synthetic mesh itself.

CONCLUSION

Utilization of the absorbable polyglactin (Vicryl) mesh as a separating layer between a synthetic mesh and intestines, did not reduce adhesions across various mesh types and composites. Histologically, however, a thick fibrous capsule replaced the Vicryl mesh and may be an important layer to prevent intestinal erosion into retromuscular synthetic meshes.

Dengue epidemiology and pathogenesis: images of the future viewed through a mirror of the past

Every year, millions of individuals throughout the world are seriously affected by dengue virus. The unavailability of a vaccine and of anti-viral drugs has made this mosquito-borne disease a serious health concern. Not only does dengue cause fatalities but it also has a profoundly negative economic impact. In recent decades, extensive research has been performed on epidemiology, vector biology, life cycle, pathogenesis, vaccine development and prevention. Although dengue research is still not at a stage to suggest definite hopes of a cure, encouraging significant advances have provided remarkable progress in the fight against infection. Recent developments indicate that both anti-viral drug and vaccine research should be pursued, in parallel with vector control programs.

Note: Design principles of a linear array multi-channel effusive metal-vapor atom source

Atomic beams can easily be produced by allowing atoms to effuse through a channel. In an earlier investigation [A. Majumder et al., Vacuum 83, 989 (2009)], we had designed, fabricated, and characterized an effusive metal-vapor source using collinear-array of multi-channel. In this note, we describe the theoretical basis of designing the source. Atom density in atomic beam has been estimated using a set of analytical expressions for long-channel operated in transparent mode. Parametric studies on aspect ratio of channel, inter-channel separation, beam width, and vertical distance from the source are carried out. They are useful in providing physical picture and optimizing design parameters.

Peripheral neuropathy in diabetes

Peripheral neuropathy is common complication of diabetes. The prevalence of peripheral neuropathy among diabetic patients on the basis of loss of vibration sensation had been studied. Detailed clinical history of each patient including age, gender, duration of diabetes, foot ulcer and biothesiometry was recorded in 211 diabetic patients between 20 and 80 years of age. It was observed that all patients under 30 years age (n = 8) felt vibration below 15 volts (no risk zone); 77% (24 out of 31) of the patients in the age group of 30-39 years were in the no risk zone, and 23% (n = 7) had mild peripheral neuropathy. Sixty per cent of the patients between 40 and 50 years (n = 44) were in the no risk zone, while 32% (n = 24) had mild peripheral neuropathy, 5% (n = 4) had moderate neuropathy and 3% (n = 2) had severe peripheral neuropathy. Amongst patients above 50 years of age, 31% (n = 31) were in no risk zone, 34% (n = 34) had mild peripheral neuropathy, 22% (n = 20) had moderate peripheral neuropathy and 13% (n = 13) had severe peripheral neuropathy. Of the patients with diabetes for less than 5 years, 58% had no neuropathy, and only 3% had severe neuropathy. Of the patients with diabetes for 5 to 15 years, 50% had no neuropathy, 30% had mild, and 10% had severe peripheral neuropathy. When patients with diabetes for over 15 years were studied, only 6% had no neuropathy and 19% had severe peripheral neuropathy. The study re-establishes that the severity of peripheral neuropathy increases with age and vibration perception decreses progressively with increased duration of diabetes. Vibration perception threshold testing helps to identify the high risk subjects who require special counselling and education to protect their feet.

Suppression of the high-p(T) charged-hadron R(AA) at the LHC

We present a parameter-free postdiction of the high-p(T) charged-hadron nuclear modification factor (R(AA)) in two centralities, measured by the CMS Collaboration in Pb-Pb collisions at the LHC. The evolution of the bulk medium is modeled using viscous fluid dynamics, with parameters adjusted to describe the soft hadron yields and elliptic flow. Assuming the dominance of radiative energy loss, we compute the medium modification of the R(AA) using a perturbative QCD-based formalism, the higher twist scheme. The transverse momentum diffusion coefficient q[over ^] is assumed to scale with the entropy density and is normalized by fitting the R(AA) in the most central Au-Au collisions at the Relativistic Heavy-Ion Collider. This setup is validated in noncentral Au-Au collisions at the Relativistic Heavy-Ion Collider and then extrapolated to Pb-Pb collisions at the LHC, keeping the relation between q[over ^] and entropy density unchanged. We obtain a satisfactory description of the CMS R(AA) over the p(T) range from 10 to 100 GeV.

Primary squamous cell carcinoma of kidney - a case report of unusual local recurrence with literature review

Primary squamous cell carcinoma of the kidney is a rare clinical entity. Primary squamous cell carcinoma is more frequently reported in urinary bladder and male urethra than in kidney. Primary renal squamous cell carcinoma (RSCC) accounts for less than 5% of urothelial tumours in urinary system. Very few cases of primary squamous cell carcinoma of kidney have been reported in the world literature. Only forty-six cases over forty four years had been reported from Mayo Clinic. These neoplasms are highly aggressive and locally advanced or metastatic at the time of presentation. Here we report such a case of primary squamous cell  carcinoma of kidney in a 50-year-old lady at a locally recurrent stage with fistulous tract formation.  Palliative radiotherapy came out to be a good clinical modality even in locally recurrent stage in this patient. DOI: http://dx.doi.org/10.3329/bjms.v11i3.11734 Bangladesh Journal of Medical Science Vol. 11 No. 03 July’12

Is immediate postoperative CA15.3 assay a predictive marker of early postoperative recurrence of carcinoma breast?

Breast cancer is still an enigma. Systemic metastasis is an important prognostic factor. Tumour marker can predict occult systemic metastasis. To evaluate the immediate postoperative CA15.3 as predictor of early recurrence, a study was carried out in 48 patients of carcinoma breast in whom immediate postoperative marker level was done. In follow-up, recurrence was noted and relation with tumour size and stage done. Null hypothesis and 't' test were used for analysis. Relation of tumour size with marker is weak but strong relation exists between tumour stage with marker and recurrence with marker. CA15.3 predicts tumour load, can also predict occult residual/occult metastatic disease better than other prognostic markers which only predict tumour behaviour.

Multiphoton ionization and Coulomb explosion of C2H5Br clusters: a mass spectrometric and charge density study

Using time-of-flight mass spectrometry (TOFMS), laser-induced photochemistry of ethyl bromide clusters has been investigated at three different wavelengths (viz. 266, 355 and 532  nm) utilizing nanosecond laser pulses of ~5 × 10(9)  W/cm(2). An interesting finding of the present work is the observation of multiply charged atomic ions of carbon and bromine at 355 and 532  nm, arising from the Coulomb explosion of (C(2)H(5)Br)(n) clusters. At 266  nm, however, the (C(2)H(5)Br)(n) clusters were found to exhibit the usual multiphoton dissociation/ionization behaviour. The TOFMS studies are complemented by measuring the total charge density of the ionized volume at 266, 355 and 532  nm, using the parallel plate method, and the charge densities were found to be ~2 × 10(9), 6 × 10(9) and 2 × 10(11)  charges/cm(3), respectively. The significantly higher charge density and the presence of energetic, multiply charged atomic ions at 532  nm are explained by the higher ponderomotive energy of the 532  nm photon, coupled with the Coulomb stability of the residual multiply charged ethyl bromide clusters generated upon laser irradiation, due to their larger effective cluster size at 532  nm than at 355 and 266  nm.

Energy and momentum deposited into a QCD medium by a jet shower

For a hard parton moving through a dense QCD medium, we compute self-consistently the energy loss and the fraction deposited into the medium due to showering and rescattering of the shower, assuming weak coupling between probe and medium. The same transport coefficients thus determine both the energy loss and its deposition into the medium. This allows a parameter free calculation of the latter once the former are computed or measured. We compute them for a weakly interacting medium. Assuming a short thermalization time for the deposited energy, we determine the medium's hydrodynamical response and obtain a conical pattern that is strongly enhanced by showering.

Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation

State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data.

Modified dihadron fragmentation functions in hot and nuclear matter

Medium modification of dihadron fragmentation functions due to gluon bremsstrahlung induced by multiple partonic scattering is studied in both deep-inelastic scattering (DIS) off large nuclei and high-energy heavy-ion collisions within the same framework of twist expansion. The modification for dihadrons is found to closely follow that for single hadrons, leading to a weak nuclear suppression of their ratios in DIS experiments. A mild enhancement of the near-side correlation of two high transverse momentum hadrons with increasing centrality is found in heavy-ion collisions due to trigger bias and the rise in parton energy loss with centrality. Successful comparisons between theory and experiment for multihadron observables in both confining and deconfined media offer comprehensive evidence for partonic energy loss as the mechanism of jet modification in dense matter.

Longitudinal broadening of quenched jets in turbulent color fields

The nearside distribution of particles at intermediate transverse momentum, associated with a high momentum trigger hadron produced in a high energy heavy-ion collision, is broadened in rapidity compared with the jet cone. This broadened distribution is thought to contain the energy lost by the progenitor parton of the trigger hadron. We show that the broadening can be explained as the final-state deflection of the gluons radiated from the hard parton inside the medium by soft, transversely oriented, turbulent color fields that arise in the presence of plasma instabilities. The magnitude of the effect is found to grow with medium size and density and diminish with increasing energy of the associated hadron.

Functional characterization and mutation analysis of family 11, Carbohydrate-Binding Module (CtCBM11) of cellulosomal bifunctional cellulase from Clostridium thermocellum

The non-catalytic, family 11 carbohydrate binding module (CtCBM11) belonging to a bifunctional cellulosomal cellulase from Clostridium thermocellum was hyper-expressed in E. coli and functionally characterized. Affinity electrophoresis of CtCBM11 on nondenaturing PAGE containing cellulosic polysaccharides showed binding with β-glucan, lichenan, hydroxyethyl cellulose and carboxymethyl cellulose. In order to elucidate the involvement of conserved aromatic residues Tyr 22, Trp 65 and Tyr 129 in the polysaccharide binding, site-directed mutagenesis was carried out and the residues were changed to alanine. The results of affinity electrophoresis and binding adsorption isotherms showed that of the three mutants Y22A, W65A and Y129A of CtCBM11, two mutants Y22A and Y129A showed no or reduced binding affinity with polysaccharides. These results showed that tyrosine residue 22 and 129 are involved in the polysaccharide binding. These residues are present in the putative binding cleft and play a critical role in the recognition of all the ligands recognized by the protein.

Cherenkov radiation from jets in heavy-ion collisions

The possibility of Cherenkov-like gluon bremsstrahlung in dense matter is studied. We point out that the occurrence of Cherenkov radiation in dense matter is sensitive to the presence of partonic bound states. This is illustrated by a calculation of the dispersion relation of a massless particle in a simple model in which it couples to two different massive resonance states. We further argue that detailed spectroscopy of jet correlations can directly probe the index of refraction of this matter, which in turn will provide information about the mass scale of these partonic bound states.

Baryon-strangeness correlations: a diagnostic of strongly interacting matter

The correlation between baryon number and strangeness elucidates the nature of strongly interacting matter, such as that formed transiently in high-energy nuclear collisions. This diagnostic can be extracted theoretically from lattice QCD calculations and experimentally from event-by-event fluctuations. The analysis of present lattice results above the critical temperature severely limits the presence of qq bound states, thus supporting a picture of independent (quasi)quarks.

Fenofibrate-induced myopathy

Fenofibrate induced myopathy is a rare adverse event. We present a case of muscle pain and quadriparesis following administration of 200mg of fenofibrate for 35 days. Patient gradually improved after stopping the drug. As per our knowledge, this is probably the first case report of fenofibrate induced myopathy from India.

Effect of osmolytes and chaperone-like action of P-protein on folding of nucleocapsid protein of Chandipura virus

Amino acid sequences of nucleocapsid proteins are mostly conserved among different rhabdoviruses. The protein plays a common functional role in different RNA viruses by enwrapping the viral genomic RNA in an RNase-resistant form. Upon expression of the nucleocapsid protein alone in COS cells and in bacteria, it forms large insoluble aggregates. In this work, we have reported for the first time the full-length cloning of the N gene of Chandipura virus and its expression in Escherichia coli in a soluble monomeric form and purification using nonionic detergents. The biological activity of the soluble recombinant protein has been tested, and it was found to possess efficient RNA-binding ability. The state of aggregation of the recombinant protein was monitored using light scattering. In the absence of nonionic detergents, it formed large aggregates. Aggregation was significantly reduced in the presence of osmolytes such as d-sorbitol. Aggregate formation was suppressed in the presence of another viral product, phosphoprotein P, in a chaperone-like manner. Both the osmolyte and phosphoprotein P also suppressed aggregation to a great extent during refolding from a guanidine hydrochloride-denatured form. The function of the phosphoprotein and osmolyte appears to be synergistic to keep the N-protein in a soluble biologically competent form in virus-infected cells.

A 72-base pair AT-rich DNA sequence element functions as a bacterial gene silencer

We have previously demonstrated that sequential activation of the bacterial ilvIH-leuO-leuABCD gene cluster involves a promoter-relay mechanism. In the current study, we show that the final activation of the leuABCD operon is through a transcriptional derepression mechanism. The leuABCD operon is transcriptionally repressed by the presence of a 318-base pair AT-rich upstream element. LeuO is required for derepressing the repressed leuABCD operon. Deletion analysis of the repressive effect of the 318-bp element has led to the identification of a 72-bp AT-rich (78% A+T) DNA sequence element, AT4, which is capable of silencing a number of unrelated promoters in addition to the leuABCD promoter. AT4-mediated gene silencing is orientation-independent and occurs within a distance of 300 base pairs. Furthermore, an increased gene-silencing effect was observed with a tandemly repeated AT4 dimer. The possible mechanism of AT4-mediated gene silencing in bacteria is discussed.

LeuO expression in response to starvation for branched-chain amino acids

The recently identified role of LeuO in the regulation of transcription has prompted us to search for the specific function(s) of LeuO in bacterial physiology. The cryptic nature of expression of leuO has previously limited such analysis. A conditional leuO expression was found when bacteria enter stationary phase and was shown to be guanosine 3',5'-bispyrophosphate-dependent. Multiple physiological events, including the stringent response, are induced upon the increase of the bacterial stress signal, guanosine 3',5'-bispyrophosphate. In this study, we tested whether LeuO was directly involved in the bacterial stringent response. LeuO was shown to be indispensable for growth resumption following a 2-h growth arrest caused by starvation for branched-chain amino acids in an E. coli K-12 relA1 strain. This result supports a functional role for LeuO in the bacterial stringent response.

ppGpp-dependent leuO expression in bacteria under stress

Despite the known potential transcription regulatory role of leuO gene product, LeuO, the condition when leuO expresses during bacterial growth cycle remains unclear. Mechanistically, leuO expression was shown to be part of promoter relay mechanism, however, the factor(s) responsible for the regulation of leuO expression is not known. Combining Northern and Western results, we demonstrate in the present communication that leuO expression is normally low and enhanced when bacteria are in transition from exponential growth to stationary phase. The stationary phase-associated leuO expression is ppGpp dependent and rpoS (sigma(s) factor) independent.

Antibacterial activity of Litsea glutinosa bark

The methanol extract of the bark of Litsea glutinosa showed antibacterial activity, comparable to chloramphenicol, against all 16 tested microorganisms.

Anomalies in hepatobiliary excretion of technetium-99m-MAG3 preparations

Technetium-99m-MAG3 is accepted as a renal tubular function agent. However, sporadic liver and gall bladder visualisation during its clinical use is clearly a disadvantage. HPLC-purified 99mTc-MAG3 samples exhibited appreciable hepatobiliary uptake (7%), and an elevated level of such uptake was observed in unpurified kit preparations, which was stated to be associated with the excretory property of the radiolabeled kit impurities. To verify this we attempted to quantitate the hepatobiliary uptake of the kit preparations with that of its radiolabeled components. The contribution of each component toward hepatobiliary uptake of the sample was calculated from their abundance in the chelate mixture and the individual biodistribution of the isolated components. However, the anticipated hepatobiliary uptake of different preparations of 99mTc-MAG3 calculated in this way was always lower than that of the experimental value determined directly. Further work is needed to explain the anomaly.

Measuring child cost--an intermediate situation between the Engel and Rothbarth measures

"This paper examines the structure of cost functions underlying the Engel and Rothbarth measures [of measuring child costs]. A generalised cost function, based on these cost functions, is proposed here. The cost of [a] child, according to this cost function, lies between the Engel and Rothbarth measures."