The Bacillus subtilis yqgC-sodA operon protects magnesium-dependent enzymes by supporting manganese efflux

Microbes encounter a myriad of stresses during their life cycle. Dysregulation of metal ion homeostasis is increasingly recognized as a key factor in host-microbe interactions. Bacterial metal ion homeostasis is tightly regulated by dedicated metalloregulators that control uptake, sequestration, trafficking, and efflux. Here, we demonstrate that deletion of the Bacillus subtilis yqgC-sodA (YS) complex operon, but not deletion of the individual genes, causes hypersensitivity to manganese (Mn). YqgC is an integral membrane protein of unknown function and SodA is a Mn-dependent superoxide dismutase (MnSOD). The YS strain has reduced expression of two Mn efflux proteins, MneP and MneS, consistent with the observed Mn sensitivity. The YS strain accumulated high levels of Mn, had increased reactive radical species (RRS), and had broad metabolic alterations that can be partially explained by the inhibition of Mg-dependent enzymes. Although the YS operon deletion strain and an efflux-deficient mneP mneS double mutant both accumulate Mn and have similar metabolic perturbations they also display phenotypic differences. Several mutations that suppressed Mn intoxication of the mneP mneS efflux mutant did not benefit the YS mutant. Further, Mn intoxication in the YS mutant, but not the mneP mneS strain, was alleviated by expression of Mg-dependent, chorismate-utilizing enzymes of the menaquinone, siderophore, and tryptophan (MST) family. Therefore, despite their phenotypic similarities, the Mn sensitivity in the mneP mneS and the yqgC-sodA deletion mutants results from distinct enzymatic vulnerabilities.

Metabolic Rewiring of Mycobacterium tuberculosis upon Drug Treatment and Antibiotics Resistance

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a significant global health challenge, further compounded by the issue of antimicrobial resistance (AMR). AMR is a result of several system-level molecular rearrangements enabling bacteria to evolve with better survival capacities: metabolic rewiring is one of them. In this review, we present a detailed analysis of the metabolic rewiring of Mtb in response to anti-TB drugs and elucidate the dynamic mechanisms of bacterial metabolism contributing to drug efficacy and resistance. We have discussed the current state of AMR, its role in the prevalence of the disease, and the limitations of current anti-TB drug regimens. Further, the concept of metabolic rewiring is defined, underscoring its relevance in understanding drug resistance and the biotransformation of drugs by Mtb. The review proceeds to discuss the metabolic adaptations of Mtb to drug treatment, and the pleiotropic effects of anti-TB drugs on Mtb metabolism. Next, the association between metabolic changes and antimycobacterial resistance, including intrinsic and acquired drug resistance, is discussed. The review concludes by summarizing the challenges of anti-TB treatment from a metabolic viewpoint, justifying the need for this discussion in the context of novel drug discovery, repositioning, and repurposing to control AMR in TB.

Mycobacterium smegmatis, a Promising Vaccine Vector for Preventing TB and Other Diseases: Vaccinomics Insights and Applications

Mycobacterium smegmatis (M.sm) is frequently used as an alternative model organism in Mycobacterium tuberculosis (M.tb) studies. While containing high sequence homology with M.tb, it is considered non-pathogenic in humans. As such it has been used to study M.tb and other infections in vivo and more recently been explored for potential therapeutic applications. A body of previous research has highlighted the potential of using genetically modified M.sm displaying rapid growth and unique immunostimulatory characteristics as an effective vaccine vector. Novel systems biology techniques can further serve to optimize these delivery constructs. In this article, we review recent advancements in vaccinomics tools that support the efficacy of a M.sm-based vaccine vector. Moreover, the integration of systems biology and molecular omics techniques in these pioneering studies heralds a potential accelerated pipeline for the development of next-generation recombinant vaccines against rapidly developing diseases.

Insights into the central role of N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmU) in peptidoglycan metabolism and its potential as a therapeutic target

Several decades after the discovery of the first antibiotic (penicillin) microbes have evolved novel mechanisms of resistance; endangering not only our abilities to combat future bacterial pandemics but many other clinical challenges such as acquired infections during surgeries. Antimicrobial resistance (AMR) is attributed to the mismanagement and overuse of these medications and is complicated by a slower rate of the discovery of novel drugs and targets. Bacterial peptidoglycan (PG), a three-dimensional mesh of glycan units, is the foundation of the cell wall that protects bacteria against environmental insults. A significant percentage of drugs target PG, however, these have been rendered ineffective due to growing drug resistance. Identifying novel druggable targets is, therefore, imperative. Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) is one of the key building blocks in PG production, biosynthesized by the bifunctional enzyme N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmU). UDP-GlcNAc metabolism has been studied in many organisms, but it holds some distinctive features in bacteria, especially regarding the bacterial GlmU enzyme. In this review, we provide an overview of different steps in PG biogenesis, discuss the biochemistry of GlmU, and summarize the characteristic structural elements of bacterial GlmU vital to its catalytic function. Finally, we will discuss various studies on the development of GlmU inhibitors and their significance in aiding future drug discoveries.

Mutations in rpoB That Confer Rifampicin Resistance Can Alter Levels of Peptidoglycan Precursors and Affect β-Lactam Susceptibility

Bacteria can adapt to stressful conditions through mutations affecting the RNA polymerase core subunits that lead to beneficial changes in transcription. In response to selection with rifampicin (RIF), mutations arise in the RIF resistance-determining region (RRDR) of rpoB that reduce antibiotic binding. These changes can also alter transcription and thereby have pleiotropic effects on bacterial fitness. Here, we studied the evolution of resistance in Bacillus subtilis to the synergistic combination of RIF and the β-lactam cefuroxime (CEF). Two independent evolution experiments led to the recovery of a single rpoB allele (S487L) that was able to confer resistance to RIF and CEF through a single mutation. Two other common RRDR mutations made the cells 32 times more sensitive to CEF (H482Y) or led to only modest CEF resistance (Q469R). The diverse effects of these three mutations on CEF resistance are correlated with differences in the expression of peptidoglycan (PG) synthesis genes and in the levels of two metabolites crucial in regulating PG synthesis, glucosamine-6-phosphate (GlcN-6-P) and UDP-N-acetylglucosamine (UDP-GlcNAc). We conclude that RRDR mutations can have widely varying effects on pathways important for cell wall biosynthesis, and this may restrict the spectrum of mutations that arise during combination therapy. IMPORTANCE Rifampicin (RIF) is one of the most valued drugs in the treatment of tuberculosis. TB treatment relies on a combination therapy and for multidrug-resistant strains may include β-lactams. Mutations in rpoB present a common route for emergence of resistance to RIF. In this study, using B. subtilis as a model, we evaluate the emergence of resistance for the synergistic combination of RIF and the β-lactam cefuroxime (CEF). One clinically relevant rpoB mutation conferred resistance to both RIF and CEF, whereas one other increased CEF sensitivity. We were able to link these CEF sensitivity phenotypes to accumulation of UDP-N-acetylglucosamine (UDP-GlcNAc), which feedback regulates GlmS activity and thereby peptidoglycan synthesis. Further, we found that higher CEF concentrations precluded the emergence of high RIF resistance. Collectively, these results suggest that multidrug treatment regimens may limit the available pathways for the evolution of antibiotic resistance.

Therapeutic Potentials of Immunometabolomic Modulations Induced by Tuberculosis Vaccination

Metabolomics is emerging as a promising tool to understand the effect of immunometabolism for the development of novel host-directed alternative therapies. Immunometabolism can modulate both innate and adaptive immunity in response to pathogens and vaccinations. For instance, infections can affect lipid and amino acid metabolism while vaccines can trigger bile acid and carbohydrate pathways. Metabolomics as a vaccinomics tool, can provide a broader picture of vaccine-induced biochemical changes and pave a path to potentiate the vaccine efficacy. Its integration with other systems biology tools or treatment modes can enhance the cure, response rate, and control over the emergence of drug-resistant strains. Mycobacterium tuberculosis (Mtb) infection can remodel the host metabolism for its survival, while there are many biochemical pathways that the host adjusts to combat the infection. Similarly, the anti-TB vaccine, Bacillus Calmette-Guerin (BCG), was also found to affect the host metabolic pathways thus modulating immune responses. In this review, we highlight the metabolomic schema of the anti-TB vaccine and its therapeutic applications. Rewiring of immune metabolism upon BCG vaccination induces different signaling pathways which lead to epigenetic modifications underlying trained immunity. Metabolic pathways such as glycolysis, central carbon metabolism, and cholesterol synthesis play an important role in these aspects of immunity. Trained immunity and its applications are increasing day by day and it can be used to develop the next generation of vaccines to treat various other infections and orphan diseases. Our goal is to provide fresh insight into this direction and connect various dots to develop a conceptual framework.

OC-021 HYBRID ROBOTIC SURGERY - USING LAPAROSCOPY TO BETTER ROBOTIC OUTCOMES

Aim

To show that Hybrid Robotic Surgery is essential for a successful and a cost effective General Surgery Robotic Surgery Program

Material & Methods

38 Consecutive cases of General Surgery done from October 2021 to June 2022 were studied with respect to usage of Robotic Instruments & Laparoscopic Instruments, the utility of each instrument, Surgical time, costs & patient outcomes.

Results

A Hybrid approach by using Laparoscopic Instruments (Ports and/or Instruments) was necessary in 38/38 patients (100%) for atleast some step & in 32/38 patients for atleast one important surgical step. Robotic Platform was used to perform Hernia Surgery like TAPP (Trans Abdominal Pre-Peritoneal) & IPOM (Intra-peritoneal Onlay Meshplasty) (n=23). Laparoscopic Instruments were used in all the cases 23/23 (100%).

Conclusions

Usage of Laparoscopic Instruments helped reduce the Surgery duration, decrease use of Robotic instruments, help negate the Haptic blind spots proving to be a cost effective & a tool for optimal Robotic utilization. Laparoscopic instrumentation and steps remain an integral part of Robotic Surgery. The findings highlight the need for dual instrument set, both Robotic & Laparoscopic Instruments, in each Robotic Surgery and underscores the importance of adequate Laparoscopy knowledge and skills for a Robotic Surgery Program.

P-059 ROBOT ASSISTED TRANS ABDOMINAL PRE-PERITONEAL (RTAPP) MESHPLASTY FOR GIANT GROIN HERNIAS - OUR HYBRID ROBOTIC SURGERY CHOREOGRAPHY FOR OPTIMIZING OUTCOMES

Aim

To demonstrate our successful, cost effective & time saving choreography for managing Large Groin Hernia with Robot assisted Trans Abdominal Pre-Peritoneal (rTAPP) Meshplasty Surgery

Materials & Methods

7 patients with Groin Hernia EHS Classification P/R M/L 3 were operated using Da Vinci Xi Robotic platform and underwent TAPP Meshplasty between October 2021 & June 2022. We noted the instruments used(Robotic and Laparoscopic), the Surgery duration & Console Time, the ease of the surgery & the Choreography, Intra-operative challenges, intra-operative change in surgical steps, post-op pain scores, analgesia usage & outcomes.

Results

Laparoscopic instruments were used in 7/7 (100%) patients for accomplishing various steps. Both flat & 3D Anatomically contoured meshs were used. Usage of Laparoscopic Instruments at various steps & in tandem with Robotic instruments optimizes the cost of the surgery, helps in decreasing surgical duration & utilization of resources. The trends evolve as one negotiates the learning curve.

Conclusions

Our study demonstrated that for Large Groin Hernia it is recommended to include Laparoscopic instruments during Robot assisted surgery along with specific surgical steps for successful completion of rTAPP in a cost-effective manner.

A hydrogel-based implantable multidrug antitubercular formulation outperforms oral delivery

We present a non-immunogenic, injectable, low molecular weight, amphiphilic hydrogel-based drug delivery system (TB-Gel) that can entrap a cocktail of four front-line antitubercular drugs, isoniazid, rifampicin, pyrazinamide, and ethambutol. We showed that TB-Gel is more effective than oral delivery of the combination of four drugs in reducing the mycobacterial infection in mice. Results show that half the dose of chemotherapeutic drugs is sufficient to achieve a comparable therapeutic effect to that of oral delivery.

Signature of strong localization and crossover conduction processes in doped ZnO thin films: synergetic effect of doping fraction and dense electronic excitations

Ga_xZn_1-xO thin films with varying Ga fraction within the solubility limit were irradiated with high-energy heavy ions to induce electronic excitations. The films show good transmittance in the visible region and a reduction of about 20% in transmittance was observed for irradiated films at higher ion fluences. The Urbach energy was estimated and showed an augmenting response upon increase in doping fraction and ion irradiation, this divulges an enhancement of localized states in the bandgap or disorder in the films. The evolution of such localized states plays a vital role in charge transport and thus the temperature dependent electrical conductivity of irradiated thin films was studied to elucidate the dominant conduction mechanisms. The detailed analysis unfolds that in the high-temperature regime (180 K <T< 300 K), the charge conduction was dominated by thermally activated band conduction followed by the nearest neighbor hopping (NNH) mechanism. Whereas in the lower temperature regime (25 K <T< 170 K), the conduction mechanism was governed by Mott-VRH (variable range hopping) followed by Efros-Shklovskii (ES)-VRH. A sudden and steep rise in resistivity below 30 K was observed for GZO films with higher doping fraction at higher ion fluence and proclaims the presence of strong localization of carriers.

Abrogation of red blood cell G6PD enzyme activity through Heat treatment: development of survey material for the UK NEQAS G6PD scheme

INTRODUCTION

Participation in external quality assessment (EQA) is central to the maintenance of high-quality laboratory results in patient diagnosis and clinical trials. Laboratories in the TAF112582 DETECTIVE study (ClinicalTrials.gov identifier: NCT01376167) are enrolled in the United Kingdom National Quality Assessment Scheme (UK NEQAS) for glucose-6-phosphate dehydrogenase (G6PD) quantitative assay, which utilizes ovine (sheep) blood as a readily available source of apparently G6PD-deficient survey material. A substitute for sheep blood was sought because some non-UK sites in the study encountered participation difficulties due to the strict regulations on the import of sheep blood into their countries.

METHODS

G6PD activity in normal human donor blood was abrogated by the action of heat under controlled conditions. Residual G6PD activity in the heated samples was measured by UK NEQAS using the Trinity Biotech 345 kit (Trinity Biotech) and a Jenway 6715 UV/Vis spectrophotometer with external temperature control to monitor enzyme kinetics and linearity over a set time. Heat-treated material was also assayed for G6PD activity and assessed for its acceptability as EQA survey material by selected UK laboratories.

RESULTS

Blood heated at 45 °C for 15 h showed a reduction in G6PD activity of 76.3 ± 4.6% (n = 6) and was considered acceptable as EQA material in terms of appearance and behaviour by the majority of UK sites in the trial.

CONCLUSIONS

We have developed a simple heat-treatment procedure to produce EQA survey material with low/intermediate G6PD activity, similar to that found in females heterozygous for G6PD deficiency.

Depletion of M. tuberculosis GlmU from Infected Murine Lungs Effects the Clearance of the Pathogen

M. tuberculosis N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmU_Mtb) is a bi-functional enzyme engaged in the synthesis of two metabolic intermediates N-acetylglucosamine-1-phosphate (GlcNAc-1-P) and UDP-GlcNAc, catalyzed by the C- and N-terminal domains respectively. UDP-GlcNAc is a key metabolite essential for the synthesis of peptidoglycan, disaccharide linker, arabinogalactan and mycothiols. While glmU_Mtb was predicted to be an essential gene, till date the role of GlmU_Mtb in modulating the in vitro growth of Mtb or its role in survival of pathogen ex vivo / in vivo have not been deciphered. Here we present the results of a comprehensive study dissecting the role of GlmU_Mtb in arbitrating the survival of the pathogen both in vitro and in vivo. We find that absence of GlmU_Mtb leads to extensive perturbation of bacterial morphology and substantial reduction in cell wall thickness under normoxic as well as hypoxic conditions. Complementation studies show that the acetyl- and uridyl- transferase activities of GlmU_Mtb are independently essential for bacterial survival in vitro, and GlmU_Mtb is also found to be essential for mycobacterial survival in THP-1 cells as well as in guinea pigs. Depletion of GlmU_Mtb from infected murine lungs, four weeks post infection, led to significant reduction in the bacillary load. The administration of Oxa33, a novel oxazolidine derivative that specifically inhibits GlmU_Mtb, to infected mice resulted in significant decrease in the bacillary load. Thus our study establishes GlmU_Mtb as a strong candidate for intervention measures against established tuberculosis infections.

The synthesis of the Mtb cell wall involves a cascade of reactions catalyzed by cytosolic and cell membrane-bound enzymes. The reaction catalyzed by GlmU_Mtb (an enzyme with acetyltransferase and uridyltransferase activities) generates UDP-GlcNAc, a central nucleotide-sugar building block of the cell wall. Apart from cell wall synthesis UDP-GlcNAc is an essential metabolite participating in other cellular processes including disaccharide linker and mycothiol biosynthesis. GlmU_Mtb shares very little sequence similarity with eukaryotic acetyltransferase and uridyltransferase enzymes. Many pathogens have alternative pathway(s) for foraging GlcNAc from the host. The present study was undertaken to see the effects of depleting GlmU_Mtb on pathogen survival in the host animal. We have generated a conditional gene replacement mutant of glmU_Mtb and find that depletion of GlmU_Mtb at any stage of bacterial growth or in mice infected with Mtb including a well-established infection, results in irreversible bacterial death due to perturbation of cell wall synthesis. We have developed a novel anti-GlmU_Mtb inhibitor (Oxa33), identified its binding site on GlmU_Mtb, and shown its specificity for GlmU_Mtb. The study demonstrates that GlmU_Mtb is a promising target for therapeutic intervention and Oxa33 can be pursued as a lead molecule.

Structure-based design of diverse inhibitors of Mycobacterium tuberculosis N-acetylglucosamine-1-phosphate uridyltransferase: combined molecular docking, dynamic simulation, and biological activity

Persistent nature of Mycobacterium tuberculosis is one of the major factors which make the drug development process monotonous against this organism. The highly lipophilic cell wall, which constituting outer mycolic acid and inner peptidoglycan layers, acts as a barrier for the drugs to enter the bacteria. The rigidity of the cell wall is imparted by the peptidoglycan layer, which is covalently linked to mycolic acid by arabinogalactan. Uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) serves as the starting material in the biosynthesis of this peptidoglycan layers. This UDP-GlcNAc is synthesized by N-acetylglucosamine-1-phosphate uridyltransferase (GlmU(Mtb)), a bi-functional enzyme with two functional sites, acetyltransferase site and uridyltransferase site. Here, we report design and screening of nine inhibitors against UTP and NAcGlc-1-P of uridyltransferase active site of glmU(Mtb). Compound 4 was showing good inhibition and was selected for further analysis. The isothermal titration calorimetry (ITC) experiments showed the binding energy pattern of compound 4 to the uridyltransferase active site is similar to that of substrate UTP. In silico molecular dynamics (MD) simulation studies, for compound 4, carried out for 10 ns showed the protein-compound complex to be stable throughout the simulation with relative rmsd in acceptable range. Hence, these compounds can serve as a starting point in the drug discovery processes against Mycobacterium tuberculosis.

Targeting NAMPT for Therapeutic Intervention in Cancer and Inflammation: Structure-Based Drug Design and Biological Screening

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate limiting enzyme that plays an important role in the synthesis of nicotinamide adenine dinucleotide (NAD) via a salvage pathway. Along with a role in bioenergetics, NAMPT regulates the activity of proteins such as SIRT-1 that utilize NAD as a cofactor. As NAD metabolism is usually high in diseased conditions, it has been hypothesized and proven that NAMPT is over expressed in various cancers and inflammatory disorders. Inhibitors targeting NAMPT could therefore be useful in treating disorders arising from aberrant NAMPT signalling. In this study, inhibitors against NAMPT were designed using an energy-based pharmacophore strategy and evaluated for efficacy in cellular assays. Besides reducing cellular pools of NAD and NMN, NAMPT inhibitors decreased concentrations of reactive oxygen species as well as mRNA levels of TNFα and IL6, thereby implicating their potential in alleviating the inflammatory process. In addition, reduced NAD levels corroborated with an induction of apoptosis in prostate cancer cell lines.

Identification of potential Mycobacterium tuberculosis topoisomerase I inhibitors: a study against active, dormant and resistant tuberculosis

Mycobacterium tuberculosis (Mtb) topoisomerase I (Topo I), involved in the relaxation of negatively supercoiled DNA, plays an important role in the viability of pathogen Mtb. Being one of the most significant enzymes; it also takes part in crucial biological pathways such as transcription and replication of the pathogen. The present study aims at the development of Mtb Topo I 3D protein structure which in turn was employed for the virtual screening of compound libraries in a process of identification of a hit molecule. The identified hit, hydroxycamptothecin, was active at 6.25 μM which was further derivatized synthetically into fifteen novel analogues. Among these, four compounds (3b, 3g, 3h and 3l) emerged to be active displaying IC50 values ranging from 2.9 to 9.3 μM against Mtb Topo I and were non-cytotoxic at 25 μM. These four compounds also proved their efficacy when tested against active, dormant and resistant forms of Mtb. The most potent inhibitor 3b was screened for in vivo anti-mycobacterial activity using zebrafish model and was found to be more effective when compared to first line anti-tubercular drugs, isoniazid and rifampicin. The binding affinity of this compound towards Mtb Topo I was analyzed by differential scanning fluorimetry which resulted in a positive shift in melting temperature when compared to the native protein thereby proving its stabilization effect over protein.

Cuckoo search algorithm based satellite image contrast and brightness enhancement using DWT-SVD

This paper presents a new contrast enhancement approach which is based on Cuckoo Search (CS) algorithm and DWT-SVD for quality improvement of the low contrast satellite images. The input image is decomposed into the four frequency subbands through Discrete Wavelet Transform (DWT), and CS algorithm used to optimize each subband of DWT and then obtains the singular value matrix of the low-low thresholded subband image and finally, it reconstructs the enhanced image by applying IDWT. The singular value matrix employed intensity information of the particular image, and any modification in the singular values changes the intensity of the given image. The experimental results show superiority of the proposed method performance in terms of PSNR, MSE, Mean and Standard Deviation over conventional and state-of-the-art techniques.

Minimally Invasive Anal Fistula Treatment (MAFT)-An Appraisal of Early Results in 416 Patients

Minimally invasive anal fistula treatment (MAFT) was introduced to minimize early postoperative morbidity, preserve sphincter continence, and reduce recurrence. We report our early experience with MAFT in 416 patients. Preoperative MRI was performed in 150 patients initially and subsequently thereafter. The technique involves fistuloscope-aided localization of internal fistula opening, examination and fulguration of all fistula tracks, and secure stapled closure of internal fistula opening within anal canal/rectum. MAFT was performed as day-care procedure in 391 patients (93.9 %). During surgery, internal fistula opening could not be located in 100 patients (24 %). Seven patients required readmission to hospital. Mean visual analog scale scores for pain on discharge and at 1 week were 3.1 (1-6) and 1.6 (0-3), respectively. Mean duration for return to normal activity was 3.2 days (2-11 days). Fistula recurrence was observed in 35/134 patients (26.1 %) at 1 year follow-up. MAFT may be performed as day-care procedure with benefits of less pain, absence of perianal wounds, faster recovery, and preservation of sphincter continence. However, long-term results from more centers are needed especially for recurrence.

[Not Available]

Spigelian hernia occurs through slit like defect in the anterior abdominal wall adjacent to the semilunar line. Most of spigelian hernias occur in the lower abdomen where the posterior sheath is deficient. The hernia ring is a well-defined defect in the transverses aponeurosis. The hernial sac, surrounded by extraperitoneal fatty tissue, is often interparietal passing through the transversus and the internal oblique aponeuroses and then spreading out beneath the intact aponeurosis of the external oblique. Spigelian hernia is in itself very rare and more over it is difficult to diagnose clinically. It has been estimated that it constitutes 0.12% of abdominal wall hernias. The spigelian hernia has been repaired by both conventional and laparoscopic approach. Laparoscopic management of spigelian hernia is well established. Most of the authors have managed it by transperitoneal approach either by placing the mesh in intraperitoneal position or by raising the peritoneal flap and placing the mesh in extraperitoneal space. There have also been case reports of management of spigelian hernia by total extraperitoneal approach. We retrospectively reviewed our experience of ten patients between 1997 and 2007. Eight patients (8/10) presented with abdominal pain and two patients (2/10) were asymptomatic. In six patients (6/10) we performed an intraperitoneal onlay IPOM repair, in two patients (2/10) transabdominal preperitoneal repair (TAPP), and in two (2/10) total extraperitoneal repair (TEP). There were no recurrences, or other morbidity at mean follow up period of 3.2 years (range 6 months to 10 years).

Iatrogenic enterotomy in laparoscopic ventral/incisional hernia repair: a single center experience of 2,346 patients over 17 years

PURPOSE

Iatrogenic enterotomy (IE) during laparoscopic ventral/incisional hernia repair (LIVHR) is reported to be associated with poorer surgical outcomes. We report our experience with diagnosis, management and complications in patients who had IE during LIVHR at our tertiary referral institute between 1994 and 2011.

METHODS

We retrospectively reviewed prospectively collected data of 2,346 patients who underwent LIVHR from 1994 to 2011. We identified 33 patients who had IE during LIVHR. All surgical procedures were performed by five consultants and fellows under supervision who followed a standardized operative protocol. Patients were followed up for 6 months to evaluate morbidity, mortality, additional surgical procedures, unplanned readmissions and hospital stay.

RESULTS

Mortality occurred in 2 patients (6 %). Complications occurred in 16 patients (48.5 %). Median hospital stay was 3 days (2-36). Unplanned readmission was required in 6 patients (18 %). In 18 patients, (55 %) additional surgical procedures were required within 6 months of LIVHR. In 5 patients, the enterotomy was recognized postoperatively. These patients had worst outcomes [mortality 40 %, additional surgical procedures were required in all patients (100 %) and median hospital stay was 12 days (range 7-36)].

CONCLUSION

Iatrogenic enterotomy is a serious complication during LIVHR. IE is associated with mortality, morbidity, additional surgical procedures, unplanned readmissions and prolonged hospital stay. In patients where IE was recognized postoperatively, the prognosis was worst.

Induction of resistance to daunorubicin in drug-sensitive leukemia p388 cells - a role of pkc-Beta-I isozyme

A role of protein kinase C (PKC) has been suggested in multidrug resistance (MDR). Because of the molecular and biochemical heterogeneity of PKC, we examined a role of PKC beta isozyme in drug sensitive murine leukemia P388 cell line. Drug sensitive P388 and MDR P388/ADR cells were treated with various concentrations of 12-deoxyphorbol-13-O-phenylacetate 20 acetate (DPPA, an agonist of PKC beta I isozyme) and examined for its effect on daunorubicin (DNR) accumulation and sensitivity to DNR. dPPA increased DNR resistance and decreased DNR accumulation in P388 cells but had no effect in P388/ADR cells. The reduced dPPA-induced DNR accumulation was due to decreased uptake without any effect on DNR efflux. Furthermore, treatment of P388 cells with dPPA was associated with translocation of PKC beta isozyme from cytosol to plasma membrane. These data suggest that PKC beta I isozyme plays a role in acquired drug resistance.

Substrate-bound crystal structures reveal features unique to Mycobacterium tuberculosis N-acetyl-glucosamine 1-phosphate uridyltransferase and a catalytic mechanism for acetyl transfer

N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmU), a bifunctional enzyme involved in bacterial cell wall synthesis is exclusive to prokaryotes. GlmU, now recognized as a promising target to develop new antibacterial drugs, catalyzes two key reactions: acetyl transfer and uridyl transfer at two independent domains. Hitherto, we identified GlmU from Mycobacterium tuberculosis (GlmU(Mtb)) to be unique in possessing a 30-residue extension at the C terminus. Here, we present the crystal structures of GlmU(Mtb) in complex with substrates/products bound at the acetyltransferase active site. Analysis of these and mutational data, allow us to infer a catalytic mechanism operative in GlmU(Mtb). In this S(N)2 reaction, His-374 and Asn-397 act as catalytic residues by enhancing the nucleophilicity of the attacking amino group of glucosamine 1-phosphate. Ser-416 and Trp-460 provide important interactions for substrate binding. A short helix at the C-terminal extension uniquely found in mycobacterial GlmU provides the highly conserved Trp-460 for substrate binding. Importantly, the structures reveal an uncommon mode of acetyl-CoA binding in GlmU(Mtb); we term this the U conformation, which is distinct from the L conformation seen in the available non-mycobacterial GlmU structures. Residues, likely determining U/L conformation, were identified, and their importance was evaluated. In addition, we identified that the primary site for PknB-mediated phosphorylation is Thr-418, near the acetyltransferase active site. Down-regulation of acetyltransferase activity upon Thr-418 phosphorylation is rationalized by the structures presented here. Overall, this work provides an insight into substrate recognition, catalytic mechanism for acetyl transfer, and features unique to GlmU(Mtb), which may be exploited for the development of inhibitors specific to GlmU.

Single port versus multiple port laparoscopic cholecystectomy-a comparative study

Single port laparoscopic cholecystectomy (SPLC) was introduced to minimize postoperative morbidity and improve cosmesis. We performed a comparative study to assess feasibility, safety and perceived benefits of SPLC. Two groups of patients (104 each) with comparable demographic characteristics were selected for SPLC and multiport laparoscopic cholecystectomy (MPLC) between May 2010 to March 2011. SPLC was performed using X cone® with 5 mm extra long telescope and 3 ports for hand instruments. MPLC was performed with traditional 4 port technique. A large window was always created during dissection to obtain the critical view of safety. Data collection was prospective. The primary end points were post-operative pain and surgical complications. Secondary end points were patient assessed cosmesis and satisfaction scores and operating time. The mean VAS scores for pain in SPLC group were higher on day 0 (SPLC 3.37 versus MPLC 2.72, p = 0.03) and equivalent to MPLC group on day 1(SPLC 1.90 versus MPLC 1.79, p = 0.06). Number of patients requiring analgesia for breakthrough pain (SPLC 21.1 % versus MPLC 26.9 %, p = 0.31) was similar. Number and nature of surgical complications was similar (SPLC 17.3 % versus MPLC 21.2 %, p =0.59). Mean patient assessed cosmesis scores (SPLC 7.96 versus MPLC 7.16, p = 0.003) and mean patient satisfaction scores (SPLC 8.66 versus MPLC 8.16, p = 0.004) were higher in SPLC group indicating better cosmesis and greater patient satisfaction. SPLC took longer to perform (61 min versus 26 min, p = 0.00). Conversion was required in 5 patients in SPLC group. SPLC appears to be feasible and safe with cosmetic benefits in selected patients. However, challenges remain to improve operative ergonomics. SPLC needs to be proven efficacious with a high safety profile to be accepted as standard laparoscopic technique.

Laparoscopic transabdominal extraperitoneal repair of lumbar hernia

Lumbar hernias need to be repaired due to the risk of incarceration and strangulation. A laparoscopic intraperitoneal approach in the modified flank position causes the intraperitoneal viscera to be displaced medially away from the hernia. The creation of a wide peritoneal flap around the hernial defect helps in mobilization of the colon, increased length of margin is available for coverage of mesh and more importantly for secure fixation of the mesh under vision to the underlying fascia. Laparoscopic lumbar hernia repair by this technique is a tensionless repair that diffuses total intra-abdominal pressure on each square inch of implanted mesh. The technique follows current principles of hernia repair and appears to confer all benefits of a minimal access approach.

Laparoscopic ventral/incisional hernia repair: a single centre experience of 1,242 patients over a period of 13 years

BACKGROUND AND PURPOSE

Laparoscopic technique is now well established for ventral/incisional hernia repair. However several issues such as optimal fixation technique, occult hernias, management of inadvertent enterotomies, postoperative seromas and recurrence require appraisal.

METHODS

A single centre retrospective review of 1,242 patients between January 1992 and June 2005 is described. All patients had laparoscopic ventral/incisional hernia repair (LVIHR) following a standardised protocol by five consultants and fellows in a dedicated minimal access surgery unit of a tertiary care hospital.

RESULTS

LVIHR was completed in 1,223 patients (98.5%). The average BMI was 32, mean defect size was 26.2 cm(2), mean operating time was 81 min and mean hospital stay was 1.9 days. The mean mesh to hernia ratio was 37.5. Occult hernias were observed in 203 (16.3%) patients and inadvertent enterotomies occurred in 21 (1.7%) patients. Mortality occurred in two patients, pulmonary embolism and cardiac dysrhythmia being the respective reasons. The most common sequel was early seroma formation (25%). Chronic pain occurred in 14.7% patients. Recurrence rate was 4.4%, which was associated with a higher BMI, use of staplers as fixation device, multiple defects and recurrent hernias. The mean follow up was 5.4 years; (range 2.4-10 years). The follow up rate was 78%.

CONCLUSION

LVIHR leads to low recurrence rates and low rates of wound and mesh infection. Occult hernias are diagnosed and optimally treated laparoscopically. However, chronic pain remains an unresolved issue.

Prospective randomized clinical trial comparing lightweight mesh and heavyweight polypropylene mesh in endoscopic totally extraperitoneal groin hernia repair

BACKGROUND

The purported advantage of lightweight large-pore meshes is improved biocompatibility that translates into lesser postoperative pain and earlier rehabilitation. However, there are concerns of increased hernia recurrence rate. We undertook a prospective randomized clinical trial to compare early and late outcome measures with the use of a lightweight (Ultrapro) mesh and heavyweight (Prolene) mesh in endoscopic totally extraperitoneal (TEP) groin hernia repair.

METHODS

A prospective study was performed on 402 patients (191 in Ultrapro and 211 in Prolene group) with bilateral groin hernias who underwent endoscopic TEP groin hernia repair from March 2006 to June 2007. All operations were performed by five consultants following a standardized operative protocol. Chronic groin pain and hernia recurrence were evaluated as primary outcome measures. Secondary outcome measure were early postoperative pain, operative time, number of fixation devices required to fix the mesh, return to normal daily activities of work, seroma, and testicular pain.

RESULTS

At 1-year follow-up, incidence in Ultrapro versus Prolene group for chronic groin pain was 1.6% vs. 4.7% (p = 0.178) and recurrence was 1.3% vs. 0.2% (p = 0.078). In Ultrapro versus Prolene group, mean visual analogue score for postoperative pain at day 7 was 1.07 vs. 1.31 (p = 0.00), mean return to normal activities was 1.82 vs. 2.09 days (p = 0.00), and mean number of fixation devices per patient required to fix the mesh was 4.22 vs. 4.08 (p = 0.043).

CONCLUSION

Lightweight meshes appear to have advantages in terms of lesser pain and early return to normal activity. However, more patients had hernia recurrence with lightweight meshes, especially for larger hernias. We surmise that the lightweight meshes have greater tendency to get displaced from their intended position during desufflation at the conclusion of endoscopic TEP repair.

Laparoscopic sleeve gastrectomy: an Indian experience-surgical technique and early results

BACKGROUND

Obesity has been observed to be on the rise in the Indian subcontinent. We report our early experience with the laparoscopic sleeve gastrectomy (LSG) for treating morbid obesity in the Indian population along with description of the surgical technique.

METHODS

The data of 75 patients who underwent LSG for the treatment of morbid obesity at the Minimal Access, Metabolic and Bariatric Surgery Centre, Sir Ganga Ram Hospital, Delhi, from November 2006 to February 2009, were retrospectively reviewed from prospective database. The gastric sleeve is created laparoscopically using sequential firings of a linear stapling device applied alongside a 36-Fr calibrating bougie. The data collected included age, gender, initial body mass index (BMI) and excess weight, the co-morbidity status, and preoperative investigations. Perioperative parameters and follow-up details [weight, BMI, excess weight loss (%EWL), resolution of co-morbidities, and postoperative investigations] were noted.

RESULTS

All procedures were completed laparoscopically. There was no major procedure-related morbidity. Hemorrhage requiring blood transfusion was observed in four patients. One patient died at 2 weeks postoperatively due to pulmonary embolism. There was a steady rise in %EWL from 31.2% at 3 months to 52.3% at 6 months, 59.13% at 1 year, and 65% at 2 years. Type II diabetes was resolved in 81.2%, hypertension in 93.75%, and dyslipidemia in 85% at 1 year.

CONCLUSION

Although long-term results are necessary to determine the benefits of the procedure, early results indicate that LSG may be a safe and feasible option for treating the morbidly obese patients.

Methotrexate bearing calcium pectinate microspheres: a platform to achieve colon-specific drug release

In the present work calcium pectinate (Ca-pectinate) microspheres were prepared to deliver methotrexate in the environment of colon. Calcium pectinate microspheres were prepared by modified emulsification method using calcium chloride as cross linker. All the formulations were evaluated for various physicochemical parameters. Particle size of the microspheres was determined using laser diffraction particle size analyzer. Encapsulation efficiency was determined by digesting with enzyme pectinase for 24 hours and swellability by equilibrium swelling in simulated gastrointestinal fluid. The in vitro drug release studies were performed in simulated gastric fluid for 2 hours and simulated intestinal fluid for 3 hours. In vitro release rate studies were also carried out in simulated colonic fluid in presence of rat caecal contents. Moreover, release rate studies were also carried out after enzyme induction by treating the rats with 1 ml of 1% w/v aqueous dispersion of pectin for 7 days. Mean particle size of the microspheres was found to be in the range of 20.82+/-1.34 to 32.26+/-1.59 microm whereas the entrapment efficiency varied from 52.28+/-0.32 to 74.01+/-3.32%. The in vitro drug release studies in simulated gastric fluid and simulated intestinal fluid showed that only 8.15+/-0.49% drug was released in 5 hours whereas most of the loaded drug was released in simulated colonic fluid containing pectinase. In vitro release rate study showed release of 69.94+/-3.46% of drug in presence of 3% rat caecal contents, which was further increased to 94.43+/-4.48% when enzyme induction was carried out for 7 days. Thus, it is concluded that calcium pectinate microspheres can be used to effectively localize the release of drug in the physiological environment of colon.

Design and development of multivesicular liposomal depot delivery system for controlled systemic delivery of acyclovir sodium

The aim of the present study was to design a depot delivery system of acyclovir sodium using multivesicular liposomes (MVLs) to overcome the limitations of conventional therapies and to investigate its in vivo effectiveness for sustained delivery. MVLs of acyclovir were prepared by the reverse phase evaporation method. The loading efficiency of the MVLs (45%-82%) was found to be 3 to 6 times higher than conventional multilamellar vesicles (MLVs). The in vitro release of acyclovir from MVL formulations was found to be in a sustained manner and only 70% of drug was released in 96 hours, whereas conventional MLVs released 80% of drug in 16 hours. Following intradermal administration to Wistar rats, the MVL formulations showed effective plasma concentration for 48 hours compared with MLVs and free drug solution (12-16 hours). C(max) values of MVL formulations were significantly less (8.6-11.4 microg/mL) than MLV and free drug solution (12.5 microg/mL). The AUC(0-48) of the MVL formulations was 1.5- and 3-fold higher compared with conventional liposomes and free drug solution, respectively. Overall, formulations containing phosphatidyl glycerol as negatively charged lipid showed better results. The MVL delivery system as an intradermal depot offers the advantage of a very high loading and controlled release of acyclovir for an extended period of time. The increase in AUC and decrease in C(max) reflects that the MVL formulations could reduce the toxic complications and limitations of conventional iv and oral therapies.

Videoendoscopically assisted combined retroperitoneal and pelvic extraperitoneal approach for aortoiliac occlusive disease

BACKGROUND

Laparoendoscopic surgery has emerged as a new method for the management of iliac and aortoiliac occlusive disease. This article describes a combined retroperitoneal and pelvic extraperitoneal approach to aorta and iliac arteries.

METHODS

A review was performed for 15 patients who underwent videoendoscopically assisted vascular bypass procedures between January 1999 and June 2003. A minimal access approach was used for access to the proximal anastomotic site (proximal common iliac or distal aorta) and creation of a tunnel for the prosthetic graft placement up to the distal anastomotic site. Altogether, 11 iliofemoral bypasses, 2 iliobifemoral bypasses and 2 aortobifemoral bypasses were performed. Patients with diffuse stenosis/long-segment occlusion and multiple lesions for whom percutaneous transluminal angioplasty with stenting proved to be unsuitable were included. The outcome parameters measured were intraoperative time, intraoperative blood loss, skin incision length, length of hospital stay, postoperative pain and analgesia requirement, and patency of graft.

RESULTS

Videoendoscopy was used to complete 14 procedures. The mean operating time was 258 +/- 49 min (range, 180-300 min) and the mean blood loss was 124 +/- 28.23 ml (range, 80-150 ml). The mean hospital stay was 6.7 +/- 4.46 days (range, 4-9 days). After a mean follow-up period of 14.4 +/- 3.55 months (range, 6-20 months), all grafts were patent.

CONCLUSION

Videoendoscopically assisted vascular surgery for iliac and aortoiliac occlusive disease by a combined retroperitoneal and pelvic extraperitoneal approach is feasible and appears to confer many advantages of minimal access surgery. However, prospective randomized trials are needed to define clearly any advantages of this approach over conventional surgery.

Solid lipid nanoparticles bearing flurbiprofen for transdermal delivery

Topical application of the drugs at the pathological sites offer potential advantages of delivering the drug directly to the site of action and thus producing high tissue concentrations of the drug. The solid lipid nanoparticles (SLN) bearing flurbiprofen were prepared by microemulsion method by dispersing o/w microemulsion in a cold aqueous surfactant medium under mechanical stirring. The SLN gel was prepared by adding SLN dispersion to polyacrylamide gel prepared by using polyacrylamide (0.5%), glycerol (10%), and water (69.5%). Shape and surface morphology was determined by scanning electron microscopy that revealed fairly spherical shape of the formulation. Percent drug entrapment was higher in SLN dispersion in comparison to SLN gel formulations. In vitro drug release, determined using cellophane membrane, showed that SLN dispersion exhibited higher drug release compared with SLN gel formulations. Both the SLN dispersion and SLN-gel formulation possessed a sustained drug release over a 24-hr period, but this sustained effect was more pronounced with SLN-gel formulations. The percent inhibition of edema after 8 hr was 55.51 +/- 0.26% in case of SLN-T4-gel, whereas flurbiprofen and SLN-T4 dispersion exhibited 28.81 +/- 0.46 and 31.89 +/- 0.82 inhibition of edema. The SLN-T4-gel not only decreased the inflammation to larger magnitude, but also sustained its effect.

Laparoscopic hepaticojejunostomy for biliary strictures: the experience of 10 patients

Hepaticojejunostomy is performed to reestablish bilioenteric continuity. During a 5-year period between July 1998 and July 2003, the authors attempted hepaticojejunostomy by a total laparoscopic approach in 10 patients with benign stricture disorders of the extrahepatic biliary tree. Six of these patients had type 1 (extrahepatic, fusiform) choledochal cyst and presented with pain, fever, and jaundice. Four of the patients had iatrogenic biliary strictures after cholecystectomy (2 patients after laparoscopic cholecystectomy and 2 patients after open cholecystectomy). These patients had a variable presentation 1 to 3 weeks after the primary procedure, with peritonitis and/or cholangitis or only progressive jaundice. For nine of the patients (90%), the procedure was completed entirely laparoscopically. The mean operative time was 326.6 min for the patients with choledochal cysts and 268 min for the patients with iatrogenic strictures. One patient with stricture after open cholecystectomy underwent conversion to an open repair because of severe anatomic distortion and fibrosis. Four patients drained bile postoperatively for 5 to 7 days. One patient with iatrogenic biliary stricture after open cholecystectomy required open revision of the anastomosis 18 months after laparoscopic hepaticojejunostomy because of recurrent cholangitis. The remaining eight patients (80%) were doing well a mean follow-up period of 3.1 years (range, 3 months to 5 years). Total laparoscopic hepaticojejunostomy is feasible for a select group of patients, but requires advanced laparoscopic skills, including intracorporeal suturing. It must be attempted only in centers well versed in advanced laparoscopic surgery.

Minimal access surgery for hydatid cyst disease: laparoscopic, thoracoscopic, and retroperitoneoscopic approach

Surgery has remained the mainstay for the treatment of hydatid cyst. The rapid development of laparoscopic techniques has encouraged surgeons to replicate principles of conventional hydatid surgery using a minimally invasive approach. Several reports have confirmed the feasibility of laparoscopic hepatic hydatid surgery. We report the use of a laparoscopic approach for cysts located in the liver, lung, and retroperitoneum. Fifteen patients with hydatid cysts, including one patient with a recurrent cyst, of various organs, including the liver, lung, and retroperitoneum, were operated on laparoscopically. Sixteen hydatid cysts were drained in a total of 15 patients. The mean operative time was 84 +/- 6 minutes (60-125 minutes). The mean duration of the hospital stay was 2.3 days (1-6 days). The mean cyst diameter was 9.2 cm (6.4-13.5 cm). No conversions to open surgery were required. One complication, a trocar-induced bowel perforation, occurred, and there was no mortality. During 3 to 44 months (mean, 27 months) of follow-up, no recurrences developed. Minimal access surgery is a safe, effective, and viable option for the management of selected patients with hydatid cysts in various locations, such as the liver, lung, and retroperitoneum.

Extraperitoneal endoscopic groin hernia repair under epidural anesthesia

We performed a prospective study to evaluate the feasibility of performing endoscopic total extraperitoneal repair of groin hernia (TEP) under epidural anesthesia in selected patients considered to be at high risk or unfit for general anesthesia. Fifty-eight endoscopic total extraperitoneal hernia repairs were performed in 36 patients between January 1997 and December 1999 under epidural anesthesia since they were considered a high risk or unfit for general anesthesia. All patients received intramuscular diclofenac sodium for preemptive analgesia. Intraoperatively, all were sedated with intravenous midazolam and fentanyl. Endoscopic TEP repair was successful under epidural anesthesia in 33 of 36 patients. In the remaining three patients, the procedure had to be converted to Lichtenstein's repair due to shoulder discomfort experienced by the patients as a result of pneumoperitoneum, which was produced by incidental peritoneal tears during extraperitoneal dissection. Intraoperatively, one patient had bleeding from the inferior epigastric artery, which was controlled with clipping of the artery. The mean operative time was 48 minutes (range, 28-72 minutes) in the TEP group and 94 minutes (range, 84-102 minutes) in the converted group. All the patients received an epidural top-up dose at the end of surgery for postoperative analgesia. All patients were ambulatory the same day. Postoperative pain was assessed by a visual analogue scale (VAS). The mean pain score was 1.2 (+/- 0.8) on discharge in the TEP group. During follow-up, seven patients developed scrotal swelling with cord induration, which was treated conservatively with scrotal support and analgesics. In all patients, resolution was observed within 6 weeks. One patient was detected to have a recurrence 4 months after surgery. Endoscopic TEP repair under epidural anesthesia appears to be safe, technically feasible, and an acceptable alternative in patients who are at high risk or unfit for general anesthesia.