Micrometer-sized negative-ion accelerator based on ultrashort laser pulse interaction with transparent solids

We report here energetic (>100 keV) negative hydrogen ions (H(-)) generated in the interaction of moderately intense (10(18) W cm(-2)) ultrashort laser pulses (45 fs) with transparent hydrogen containing solid targets. An unambiguous and consistent detection of negative hydrogen ions, with a flux of 8×10(11)H(-) ions/sr, has been observed in every single laser shot, using a Thomson parabola ion spectrograph. Simple estimates based on charge transfer cross sections match well with experimental observations. Our method offers the implementation of an intense, ultrashort laser based negative-ion source at a higher repetition rate, which can be important for various applications.

Calibration-free 2f WMS with in situ real-time laser characterization and 2f RAM nulling

This Letter demonstrates a new calibration-free 2f wavelength modulation spectroscopy (WMS) technique to measure gas concentration and pressure without the need for laser precharacterization. A 1650-nm laser diode is used for methane concentration and pressure measurements for pressures up to 4 bar and for a modulation index (m) of 2.2. All laser parameters such as the intensity, linear and nonlinear intensity modulation (IM), frequency modulation (FM) characteristics, the phase difference ψ1 between the FM and the linear IM, and the phase difference ψ2 between the FM and the nonlinear IM are accurately estimated in situ and in real time. This technique accounts for variations in these parameters that arise due to scanning of the laser's center wavelength, laser temperature variations, and aging of the laser. The laser is modulated at its phase quadrature frequency at which the linear IM and the FM are orthogonal to each other (ψ1=90°). This ensures that the two linear IM-dependent distorting Fourier components are orthogonal to the detection axis, and the undistorted 2f signal is recovered. This simplifies the simulation and gas parameter-extraction process. Finally, 2f RAM nulling is implemented to remove the significant absorption-independent 2f residual amplitude-modulation (RAM) signal that is seen to cause significant distortion of the 2f signal and detector saturation.

Transient expression in HEK 293 cells: an alternative to E. coli for the production of secreted and intracellular mammalian proteins

Transient transfection of human embryonic kidney cells (HEK 293) enables the rapid and affordable lab-scale production of recombinant proteins. In this chapter protocols for the expression and purification of both secreted and intracellular proteins using transient expression in HEK 293 cells are described.

Role of target material in proton acceleration from thin foils irradiated by ultrashort laser pulses

We report on the proton acceleration studies from thin metallic foils of varying atomic number (Z) and thicknesses, investigated using a 45 fs, 10 TW Ti:sapphire laser system. An optimum foil thickness was observed for efficient proton acceleration for our laser conditions, dictated by the laser ASE prepulse and hot electron propagation behavior inside the material. The hydrodynamic simulations for ASE prepulse support the experimental observation. The observed maximum proton energy at different thicknesses for a given element is in good agreement with the reported scaling laws. The results with foils of different atomic number Z suggest that a judicious choice of the foil material can enhance the proton acceleration efficiency, resulting into higher proton energy.

Comparative genomic analysis reveals 2-oxoacid dehydrogenase complex lipoylation correlation with aerobiosis in archaea

Metagenomic analyses have advanced our understanding of ecological microbial diversity, but to what extent can metagenomic data be used to predict the metabolic capacity of difficult-to-study organisms and their abiotic environmental interactions? We tackle this question, using a comparative genomic approach, by considering the molecular basis of aerobiosis within archaea. Lipoylation, the covalent attachment of lipoic acid to 2-oxoacid dehydrogenase multienzyme complexes (OADHCs), is essential for metabolism in aerobic bacteria and eukarya. Lipoylation is catalysed either by lipoate protein ligase (LplA), which in archaea is typically encoded by two genes (LplA-N and LplA-C), or by a lipoyl(octanoyl) transferase (LipB or LipM) plus a lipoic acid synthetase (LipA). Does the genomic presence of lipoylation and OADHC genes across archaea from diverse habitats correlate with aerobiosis? First, analyses of 11,826 biotin protein ligase (BPL)-LplA-LipB transferase family members and 147 archaeal genomes identified 85 species with lipoylation capabilities and provided support for multiple ancestral acquisitions of lipoylation pathways during archaeal evolution. Second, with the exception of the Sulfolobales order, the majority of species possessing lipoylation systems exclusively retain LplA, or either LipB or LipM, consistent with archaeal genome streamlining. Third, obligate anaerobic archaea display widespread loss of lipoylation and OADHC genes. Conversely, a high level of correspondence is observed between aerobiosis and the presence of LplA/LipB/LipM, LipA and OADHC E2, consistent with the role of lipoylation in aerobic metabolism. This correspondence between OADHC lipoylation capacity and aerobiosis indicates that genomic pathway profiling in archaea is informative and that well characterized pathways may be predictive in relation to abiotic conditions in difficult-to-study extremophiles. Given the highly variable retention of gene repertoires across the archaea, the extension of comparative genomic pathway profiling to broader metabolic and homeostasis networks should be useful in revealing characteristics from metagenomic datasets related to adaptations to diverse environments.

Ochratoxin A induces cytotoxicity, DNA damage and apoptosis in rat hepatocyte primary cell culture at nanomolar concentration

Ochratoxin A (OTA), a mycotoxin produced by several species of Aspergillus and Penicillum, is widely found as a contaminant of food. OTA exhibits a wide range of toxic activities, including nephro- and hepatotoxicity. Although the mechanisms of its genotoxicity and carcinogenicity have been studied before, many controversial results have been published. In addition, the studies were mostly conducted with kidney cells. Therefore, the present study used a primary culture of Wistar rat hepatocytes incubated with increasing concentrations of OTA (2.0-6.0 nanomolar). OTA treatment showed dose-dependent cytotoxicity and DNA damage. Further, flow cytometric analysis of hepatocytes showed dose-dependent apoptosis, suggesting that OTA-induced hepatotoxicity is, may be partly, mediated by apoptosis. Vascular endothelial growth factor gene, a potent pro-angiogenic in hepatocellular carcinoma and responsible for hepatocyte regeneration, did not show any change with OTA treatment, as analysed by reverse transcription polymerase chain reaction. Thus, the present data indicated OTA-induced rat hepatotoxicity in vitro at nanomolar concentration, which inferred a major possible target other than kidney cells.

K/B×N serum transfer arthritis is delayed and less severe in leukaemia inhibitory factor (LIF)-deficient mice

This study is investigating the role of leukaemia inhibitory factor (LIF) in the development of inflammation and joint damage in the mouse K/B×N serum transfer arthritis model. LIF knock-out (LIF(-/-)) mice were generated by mating heterozygote females (LIF(+/-)) with heterozygote males. Arthritis was induced in 8-20-week-old LIF knock-out mice (LIF(-/-)) by intraperitoneal injection of pooled K/B×N sera (50 µl) on days 0 and 2. Clinical disease was scored daily for 6 days. Safranin-O and haematoxylin-stained sections were scored for synovitis, joint space exudate, cartilage degradation and bone damage. RNA was extracted from ankle joints and used to investigate gene expression levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1, LIF, LIF receptor, oncostatin M (OSM), OSM receptor, IL-6 and their common receptor subunit gp130 by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results show that wild-type mice developed severe clinically overt polyarthritis. In contrast, LIF(-/-) mice showed a more than 50% reduction in clinical arthritis severity. Significantly lower histological scores were observed in LIF(-/-) mice compared to wild-type disease controls. LIF(-/-) mice had histopathological scores that were similar to normal healthy mice. IL-6 subfamily cytokine and receptor subunit expression remained unchanged. The expression levels for IL-6 were reduced significantly in all the diseased mice, whether wild-type or LIF(-/-) mice (P < 0·001), compared to healthy wild-type mice. We conclude that LIF contributes to the development of disease in the K/B×N serum transfer model of arthritis. These results provide further evidence for the role of LIF in inflammation and cartilage bone resorption and provide impetus to test the effects of LIF blockade as a therapeutic strategy in rheumatoid arthritis.

Phase velocity and particle injection in a self-modulated proton-driven plasma wakefield accelerator

It is demonstrated that the performance of the self-modulated proton driver plasma wakefield accelerator is strongly affected by the reduced phase velocity of the plasma wave. Using analytical theory and particle-in-cell simulations, we show that the reduction is largest during the linear stage of self-modulation. As the instability nonlinearly saturates, the phase velocity approaches that of the driver. The deleterious effects of the wake's dynamics on the maximum energy gain of accelerated electrons can be avoided using side-injections of electrons, or by controlling the wake's phase velocity by smooth plasma density gradients.

Immunomodulatory efficacy of nisin--a bacterial lantibiotic peptide

Nisin is a peptide bacteriocin, grouped under the category of lantibiotics. It is naturally produced by Lactococcus lactis to eliminate other competing gram-positive bacteria from its vicinity. Moreover under certain conditions it is reported to be effective against a broad range of gram-negative bacteria as well. Thus, it has been widely used as a safe food preservative especially in the dairy industry. Because of its wide-scale consumption, its effect on eukaryotic cells should be of great concern. Here we examine the immunomodulatory efficacy of nisin in vitro. MTT-based cytotoxicity assay demonstrated nisin's cytotoxicity on human T-cell lymphoma Jurkat cells, Molt-4 cells and freshly cultured human lymphocytes at over 200 µM concentration (IC(50) 225 µM). The cell death mechanism induced by nisin in all these lymphocyte types was independent of oligonucleosomal DNA fragmentation, as analyzed by agarose gel electrophoresis and comet assay. Additionally, scanning electron microscope and fluorescence microscopy demonstrated the ability of nisin to activate human PMNs in vitro. Nisin-activated neutrophils extruded intact nuclear chromatin to form NETs, well known for neutralization of virulence factors and extermination of bacterial pathogens. Nisin's presence also elevated neutrophil intracellular superoxide levels, normally produced by activated NADPH oxidase and prerequisite to NET formation. These nisin-induced responses in cellular representatives of two separate branches of human immune system-adaptive and innate-although leading to cell death, did not include DNA fragmentation. From these findings, we propose that nisin might trigger similar AICD mechanisms in lymphocytes and neutrophils, different from conventional apoptosis which involves DNA fragmentation.

A structural basis for Staphylococcal complement subversion: X-ray structure of the complement-binding domain of Staphylococcus aureus protein Sbi in complex with ligand C3d

The structure of the complement-binding domain of Staphylococcus aureus protein Sbi (Sbi-IV) in complex with ligand C3d is presented. The 1.7Å resolution structure reveals the molecular details of the recognition of thioester-containing fragment C3d of the central complement component C3, involving interactions between residues of Sbi-IV helix α2 and the acidic concave surface of C3d. The complex provides a structural basis for the binding preference of Sbi for native C3 over C3b and explains how Sbi-IV inhibits the interaction between C3d and complement receptor 2. A second C3d binding site on Sbi-IV is identified in the crystal structure that is not observed in related S. aureus C3 inhibitors Efb-C and Ehp. This binding mode perhaps hints as to how Sbi-IV, as part of Sbi, forms a C3b-Sbi adduct and causes futile consumption of C3, an extraordinary aspect of Sbi function that is not shared by any other known Staphylococcal complement inhibitor.

Ferritin concentrations in synovial fluid are higher in osteoarthritis patients with HFE gene mutations (C282Y or H63D)

OBJECTIVES

In view of the clinical similarities between polyarticular osteoarthritis (POA) with metacarpophalangeal (MCP) joint involvement and the arthropathy that occurs in hereditary haemochromatosis (HH), it was hypothesized that osteochondral damage in both disorders may be due to localized iron overload. Accordingly, it was predicted that the concentration of ferritin in synovial fluid (SF) would be higher in OA patients with HFE gene mutations than in HFE wild-type (wt) OA patients. The aim of this study was to test this proposition.

METHODS

Sequential patients with physician-diagnosed OA and, for comparison, diverse inflammatory diseases of the joints, who required diagnostic or therapeutic arthrocentesis, were studied. Participants underwent HFE genotyping. SF samples were assayed for ferritin and also for selected cytokines and matrix metalloproteinases (MMPs).

RESULTS

Seventy-three patients with diverse rheumatic disorders were recruited. Of the 29 patients who had knee OA, 15 were wt and 14 were heterozygous for HFE mutations (C282Y or H63D). Mean SF ferritin concentrations in the wt and heterozygous OA groups were 273 and 655 ng/mL, respectively (p = 0.0146).

CONCLUSIONS

A predicted difference in SF ferritin concentrations in patients with knee OA was confirmed. Concentrations of ferritin in the SF were found to be two- to threefold higher in knee OA patients with HFE gene mutations compared to wt patients. This finding is consistent with the possibility that, in OA patients with HFE gene mutations, localized iron overload may contribute either directly or indirectly to osteochondral damage, possibly in a similar way to that which occurs in the arthropathy that complicates HH.

Photorhabdus adhesion modification protein (Pam) binds extracellular polysaccharide and alters bacterial attachment

BACKGROUND

Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts.

RESULTS

A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28 degrees C) and human (37 degrees C) temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS)-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR) binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora.

CONCLUSIONS

We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect through mediation of EPS properties. Despite its abundance and conservation in the genus, we find no evidence for a role of Pam in either virulence or symbiosis.

A unique lipoylation system in the Archaea. Lipoylation in Thermoplasma acidophilum requires two proteins

Members of the 2-oxoacid dehydrogenase multienzyme complex family play a key role in the pathways of central metabolism. Post-translational lipoylation of the dihydrolipoyl acyltransferase component of these complexes is essential for their activity, the lipoyllysine moiety performing the transfer of substrates and intermediates between the different active sites within these multienzyme systems. We have previously shown that the thermophilic archaeon, Thermoplasma acidophilum, has a four-gene cluster encoding the components of such a complex, which, when recombinantly expressed in Escherichia coli, can be assembled into an active multienzyme in vitro. Crucially, the E. coli host carries out the required lipoylation of the archaeal dihydrolipoyl acyltransferase component. Because active 2-oxoacid dehydrogenase multienzyme complexes have never been detected in any archaeon, the question arises as to whether Archaea possess a functional lipoylation system. In this study, we report the cloning and heterologous expression of two genes from Tp. acidophilum whose protein products together show significant sequence identity with the single lipoate protein ligase enzyme of bacteria. We demonstrate that both recombinantly expressed Tp. acidophilum proteins are required for lipoylation of the acyltransferase, and that the two proteins associate together to carry out this post-translational modification. From the published DNA sequences, we suggest the presence of functional transcriptional and translational regulatory elements, and furthermore we present preliminary evidence that lipoylation occurs in vivo in Tp. acidophilum. This is the first report of the lipoylation machinery in the Archaea, which is unique in that the catalytic activity is dependent on two separate gene products.

Sclerotherapy for hydrocele revisited: a prospective randomised study

PURPOSE

A prospective randomised trial to study the efficacy and safety of hydrocele sclerotherapy with phenol and polidocanol.

METHODS

Eighty-six patients with unilateral primary vaginal hydroceles were randomised into three groups: group 1 (phenol sclerotherapy) - 29 patients, group 2 (polidocanol sclerotherapy) - 29 patients and group 3 (operative treatment) - 28 patients. Sclerotherapy was performed on outpatient basis using either 5-10 ml of 5% phenol or 2-4 ml of 1% polidocanol, while patients in group 3 underwent surgical repair of hydrocele (Jaboulay's procedure). Statistical analysis was performed using ANOVA.

RESULTS

The cure rates in group 1, 2 and 3 were 96.5%, 51.7% and 100%, respectively. The pain scores (visual analogue scale) in group 1, 2 and 3 at 1 week and 1 month were 14.5 and 1.8; 10.1 and 1.3; 64.0 and 10.6, respectively. There was significant difference among the three groups in mean hospital stay (1.8, 1.5 and 9.7 hours, respectively) and time to work resumption (1.3, 1.1 and 12.7 days, respectively). Statistically significant differences in pain scores and complications were observed between sclerotherapy and operative groups.

CONCLUSION

Five percent phenol is a better sclerosant than 1% polidocanol and is as efficacious as operative treatment, with lesser morbidity and similar safety profile.

Structure-function analysis of the C3 binding region of Staphylococcus aureus immune subversion protein Sbi

Among the recently discovered Staphylococcus aureus immune evasion proteins, Sbi is unique in its ability to interact with components of both the adaptive and innate immune systems of the host. Sbi domains I and II (Sbi-I and Sbi-II) bind IgG. Sbi domain IV (residues 198-266) binds the central complement protein C3. When linked to Sbi-III, Sbi-IV induces a futile consumption of complement via alternative pathway activation, whereas isolated Sbi-IV specifically inhibits the alternative pathway without complement consumption. Here we have determined the three-dimensional structure of Sbi-IV by NMR spectroscopy, showing that Sbi-IV adopts a three-helix bundle fold similar to those of the S. aureus complement inhibitors Efb-C, Ehp, and SCIN. The (1)H-(15)N HSQC spectrum of Sbi-III indicates that this domain, essential for futile complement consumption, is natively unfolded, at least when isolated from the rest of Sbi. Sbi-IV and Sbi-III-IV both bind C3dg with 1:1 stoichiometry and submicromolar affinity. Despite low overall sequence identity, Sbi possesses the same residues as Efb at two positions essential for Efb-C binding to C3d. Mutation to alanine of either of these residues, Arg-231 and Asn-238, abolishes both Sbi-IV binding to C3dg and Sbi-IV alternative pathway inhibition. The almost complete conservation of Sbi-III and Sbi-IV amino acid sequences across more than 30 strains isolated from human and animal hosts indicates that the unique mechanism of Sbi in complement system subversion is a feature of infections of both humans and economically important animals.

Characterization of a new isolate of Pseudomonas fluorescens strain Psd as a potential biocontrol agent

AIMS

Evaluation of a new isolate of Pseudomonas fluorescens for its biocontrol properties.

METHODS AND RESULTS

Strain Psd identified as Ps. fluorescens, produces secondary metabolites that are toxic to some plant-pathogenic fungi. Inhibition of fungal growth of Fusarium oxysporum and Verticillium dahliae in the presence of bacterial culture filtrate provided the first clue to its biocontrol properties. In order to determine the basis for antifungal properties, antibiotics were extracted and analysed by TLC. Both pyrrolnitrin and phenazines could be detected in the culture of Psd. Presence of response regulator gene gacA of the two component regulatory system (GacS/GacA) was established by PCR amplification and sequencing. Sequence comparison of gacA justified the taxonomic position of this strain among the known members of Pseudomonadaceae. Synthesis of other compounds like toxic lipodepsipeptide, siderophores, and HCN was also confirmed by appropriate biochemical tests.

CONCLUSION

Characterization of strain Psd by various biochemical/plate tests followed by chromatographic identification of antibiotics, demonstrates its multifunctional biocontrol property. Response regulator gene gacA provides an additional genetic marker for the phylogenetic studies.

SIGNIFICANCE AND IMPACT OF THE STUDY

Ps. fluorescens strain Psd with its multifunctional biocontrol property can be used to bioprotect the crop plants from phytopathogens.

The 2-oxoacid dehydrogenase multi-enzyme complex of the archaeon Thermoplasma acidophilum - recombinant expression, assembly and characterization

The aerobic archaea possess four closely spaced, adjacent genes that encode proteins showing significant sequence identities with the bacterial and eukaryal components comprising the 2-oxoacid dehydrogenase multi-enzyme complexes. However, catalytic activities of such complexes have never been detected in the archaea, although 2-oxoacid ferredoxin oxidoreductases that catalyze the equivalent metabolic reactions are present. In the current paper, we clone and express the four genes from the thermophilic archaeon, Thermoplasma acidophilum, and demonstrate that the recombinant enzymes are active and assemble into a large (M(r) = 5 x 10(6)) multi-enzyme complex. The post-translational incorporation of lipoic acid into the transacylase component of the complex is demonstrated, as is the assembly of this enzyme into a 24-mer core to which the other components bind to give the functional multi-enzyme system. This assembled complex is shown to catalyze the oxidative decarboxylation of branched-chain 2-oxoacids and pyruvate to their corresponding acyl-CoA derivatives. Our data constitute the first proof that the archaea possess a functional 2-oxoacid dehydrogenase complex.

Laparoscopic management of a nonobstetric emergency in the third trimester of pregnancy

BACKGROUND

Laparoscopic management of nonobstetric acute abdominal pain during pregnancy remains controversial. A gestational age of 26 to 28 weeks has been considered the upper limit for laparoscopy by some authors. A case series of nonobstetric surgery in advanced pregnancy is reported.

METHODS

Third-trimester patients who underwent surgery between 1997 and 2006 were reviewed.

RESULTS

Laparoscopic surgery was performed for nonobstetric emergencies during the third trimester for 11 patients. Four patients underwent open surgery. The laparoscopic surgery group included five cholecystectomies, four appendectomies, and two adenexal surgeries. The laparoscopic surgery procedure was successfully completed for 10 patients. Of these 10 patients, 9 had no complications and went on to deliver a healthy term infant. One patient went into preterm labor after a laparoscopic appendectomy for perforated acute appendicitis with purulent peritonitis and delivered a viable infant at 34 weeks. Another patient at 29 weeks of gestation underwent a diagnostic laparoscopy for abdominal pain. Adenexal torsion of a large multicystic ovarian mass led to a laparotomy (obstetrician preference) and right salpingo-oophrectomy. Her postoperative course was complicated by an episode of sudden syncope, hypotension, and fetal distress on postoperative day 3. An emergent laparotomy showed hemoperitoneum attributable to bleeding from the ovarian pedicle. A cesarean section delivery of a preterm infant requiring neonatal resuscitation was performed. The open surgery group included four patients. Two of the patients underwent appendectomies at 35 and 33 weeks, respectively, followed by a term delivery. The remaining two patients underwent emergent colectomies with a cesarean section delivery at 31 and 38 weeks, respectively.

CONCLUSIONS

This study demonstrated that laparoscopic surgery in the third trimester of pregnancy is feasible and can be performed safely with an acceptable risk to the fetus and the mother. Access to the pregnant abdomen is easily obtained. Space generally is not a problem, and there is minimal uterine manipulation.

Characterisation of receptor binding by the chemotaxis inhibitory protein of Staphylococcus aureus and the effects of the host immune response

The chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) is reported to bind to the receptors for C5a and formylated peptides and has been proposed as a promising lead for the development of new anti-inflammatory compounds. Here we have examined the receptor specificity and mode of action of recombinant CHIPS_28–149 and also the immune response to CHIPS_28–149 in patients with S. aureus infections and in uninfected controls. Recombinant CHIPS_28–149 bound with high affinity to the human C5a receptor (C5aR), but had low affinity for the second C5a receptor, C5L2, and the formyl peptide receptor, FPR. Although ligand binding to C5aR was potently inhibited, CHIPS_28–149 had much weaker effects on ligand binding to C5L2 and FPR. Similarly, CHIPS_28–149 potently inhibited the ligand-induced activation of C5aR but was less potent at inhibition via FPR. NMR studies showed that CHIPS_28–149 bound directly to the N-terminus of C5aR but not C5L2, and CHIPS_28–149 residues involved in the interaction were identified by chemical shift analysis. All human sera examined contained high titres of IgG and IgA reactivity against CHIPS_28–149, and no correlation was observed between infection status at the time of serum collection and antibody titre. Individual serum samples promoted or inhibited the binding of CHIPS_28–149 to C5aR, or had no effect. IgG depletion of serum samples abrogated the effects on CHIPS binding, demonstrating that these were antibody mediated. Sera from infected individuals were more likely to inhibit CHIPS_28–149 binding than sera from healthy controls. However, high antibody titres correlated well with both inhibition and enhancement of CHIPS_28–149 binding to C5aR; this suggests that the inhibitory effect relates to epitope specificity rather than greater antibody binding. We conclude that CHIPS is likely to be too immunogenic to be used as an anti-inflammatory treatment but that some antibodies against CHIPS may be useful in the treatment of S. aureus infections.

Congenital stridor due to bilateral vocal cord palsy

Congenital stridor is one of the rare presentations of respiratory distress at birth. The commonest cause of congenital stridor is laryngomalacia, which accounts for 60% of the causes. The other common causes are congenital subglottic stenosis and vocal cord palsy (VCP). VCP is usually unilateral and most often linked with birth trauma, and is temporary. Bilateral palsy can be associated with other congenital anomalies. The current report describes a case of congenital bilateral VCP, not related to birth trauma and severe enough to require tracheostomy.

Delayed internal fixation of fractures of the neck of the femur in young adults. A prospective, randomised study comparing closed and open reduction

We have compared the results and complications after closed and open reduction with ternal fixation in young adults with displaced intracapsular fractures (Garden grades III and IV) of the neck of the femur. We also studied the risk factors which influenced nonunion and the development of avascular necrosis (AVN). A total of 102 patients aged between 15 and 50 years was randomised to receive either closed or open reduction. Both groups were compared for age, gender, time to surgery and posterior comminution as well as for union and complications. Using univariate and multivariate analysis the factors influencing nonunion and AVN were assessed. Of the 102 patients, 92 were available for review. There was no significant difference between the groups in terms of union (p = 0.93) and AVN at two years (p = 0.85). Posterior comminution, poor reduction and improper placement of the screws were the major factors contributing to nonunion. The overall incidence of AVN was 16.3% (15 of 92 patients) and it was not influenced by these factors. A delay of more than 48 hours before surgery did not influence the rate of union or the development of AVN when compared with operation within 48 hours of injury.

Structural analysis of Salmonella enterica effector protein SopD

Salmonella outer protein D (SopD) is a type III secreted virulence effector protein from Salmonella enterica. Full-length SopD and SopD lacking 16 amino acids at the N-terminus (SopDDeltaN) have been expressed as fusions with GST in Escherichia coli, purified with a typical yield of 20-30 mg per litre of cell culture and crystallized. Biophysical characterization has been carried out mainly on SopDDeltaN. Analytical size exclusion chromatography shows that SopDDeltaN is monomeric and probably globular in aqueous solution. The secondary structure composition, calculated from the CD spectrum, is mixed (38% alpha-helix and 26% beta-strand). Sequence analysis indicates that SopD contains a coiled coil motif, as found in numerous other type III secretion system-associated proteins. This suggests that SopD has the potential for one or more heterotypic protein-protein interactions. Limited trypsin digestion of SopDDeltaN, monitored by both one-dimensional proton NMR spectroscopy and SDS-PAGE, shows that the protein has a large, protease-resistant core domain of 286 amino acid residues. This single-domain architecture suggests that SopD lacks a cognate chaperone. In crystallization trials, SopDDeltaN produced better crystals than either full-length SopD or trypsin-digested SopDDeltaN. Diffraction to 3.0 A resolution has so far been obtained from crystals of SopDDeltaN.

Biophysical characterization of the catalytic domain of guanine nucleotide exchange factor BopE from Burkholderia pseudomallei

BopE is a type III secreted protein from Burkholderia pseudomallei, the aetiological agent of melioidosis. Like its Salmonella homologues SopE and SopE2, BopE is a guanine nucleotide exchange factor for Rho GTPases. It is thought that, in order to be secreted by the type III system, proteins must be unfolded or only partially folded. As part of a study of B. pseudomallei virulence proteins, we have expressed, purified and characterized the catalytic domain of BopE (amino acids 78-261). Analytical ultracentrifugation experiments in conjunction with analytical size exclusion chromatography show that BopE(78-261) is monomeric in aqueous solution. CD spectroscopy indicates that the protein is predominantly alpha-helical, with predicted secondary structure composition of 59% alpha-helix and 7% beta-strand. NMR spectroscopy confirms that BopE(78-261) adopts a single, stable conformation. In differential scanning calorimetry experiments, thermal denaturation of BopE(78-261) (T(m) 52 degrees C) is reversible. Also, the secondary structure composition of BopE(78-261) changes little over a range of pH values from 3.5 to 10.5. BopE may therefore fold spontaneously to a functional form upon secretion into the host cell cytoplasm, and retains a native or native-like fold in varied environments. These properties are likely to be advantageous for a secreted bacterial effector protein.

Analgesic effect of expressed breast milk in procedural pain in term neonates: a randomized, placebo-controlled, double-blind trial

AIM

To assess the effectiveness of expressed breast milk (EBM) in reducing pain due to venepuncture, in term neonates, as measured by behavioural and physiological observations.

METHODS

This randomized, placebo-controlled, double-blind trial involved 81 full-term neonates, up to 4 wk of postnatal age, who needed venepuncture for blood investigations. Two minutes before the venepuncture, in the intervention arm, 40 babies received 5 ml of EBM, while 41 babies in control group received 5 ml of distilled water (DW) as placebo. Two observers who were blinded to the intervention recorded the physiological (heart rate and oxygen saturation) and behavioural parameters [duration of crying and modified Neonatal Facial Coding Scores (NFCS)] after the venepuncture.

RESULTS

There was no difference in the baseline characteristics of the neonates in the two groups. The duration of crying was significantly shorter in babies fed EBM [median 38.5 s, interquartile range (IQR) 9.5-57.5 s] than in those fed DW (median 90 s, IQR 28-210 s). The mean duration of crying in EBM group was shorter by 70.7 (95% confidence interval 36.6-104.9) s. The modified NFCS at 0, 1 and 3 min was significantly lower (p < 0.01) in the EBM than in the DW group. The change in heart rate and oxygen saturation was significantly lower in the EBM group and returned to baseline values sooner than in the DW group.

CONCLUSION

Feeding 5 ml of EBM before venepuncture is effective in reducing symptoms due to pain in term neonates.

Efficacy of antibodies against Escherichia coli expressed chimeric recombinant protein encompassing multiple epitopes of zona pellucida glycoproteins to inhibit in vitro human sperm-egg binding

To minimize ovarian dysfunction subsequent to immunization with zona pellucida (ZP) glycoproteins, synthetic peptides encompassing the antigenic B cell epitopes as immunogens have been proposed. In this study, attempts have been made to clone and express a recombinant chimeric protein encompassing the epitopes corresponding to bonnet monkey (Macaca radiata) ZP glycoprotein-1 (bmZP1, amino acid residues 132-147), ZP glycoprotein-2 (bmZP2, amino acid residues 86-113), and ZP glycoprotein-3 (bmZP3, amino acid residues 324-347). The above chimeric recombinant protein (r-bmZP123) was expressed as a polyhistidine fusion protein in Escherichia coli. Immunoblot with murine monoclonal antibody, MA-813, generated against recombinant bmZP1 revealed a major band of approximately 10 kDa. The r-bmZP123 was purified on nickel-nitrilotriacetic acid resin under denaturing conditions. The female rabbits immunized with purified r-bmZP123 conjugated to diphtheria toxoid (DT) generated antibodies that reacted with r-bmZP123 and DT in an ELISA. In addition, the immune sera also reacted with E. coli expressed recombinant bmZP1, bmZP2, and bmZP3. In an indirect immunofluorescence assay, the antibodies against r-bmZP123 recognized native ZP of bonnet monkey as well as human. The immune sera also inhibited, in vitro, the binding of human spermatozoa to the human zona in the hemizona assay (HZA). These studies, for the first time, demonstrate the feasibility of assembling multiple epitopes of different ZP glycoproteins as a recombinant protein that elicit antibodies which are reactive with native zona and also inhibit, in vitro, human sperm-oocyte binding.

Native zona pellucida reactivity and in-vitro effect on human sperm-egg binding with antisera against bonnet monkey ZP1 and ZP3 synthetic peptides

In mammals, zona pellucida glycoprotein-3 (ZP3) is the putative ligand for primary sperm binding and induces the acrosome reaction. Recent evidence suggests that zona pellucida glycoprotein-1 (ZP1) also play an important role, in some species, during fertilization. In order to identify synthetic peptide immunogens capable of inducing antibodies reactive with native zona and inhibiting sperm-oocyte interaction, peptide encompassing the amino acid (aa) residues 334-343 of bonnet monkey ZP3 (bmZP3) was synthesized co-linearly with a 'promiscuous' T-cell epitope of circumsporozoite protein (CSP, 378-398 aa) of Plasmodium falciparum. In addition, four peptides corresponding to bonnet monkey ZP1 (bmZP1((58-79 aa)), bmZP1((136-153 aa)), bmZP1((212-228 aa)) and bmZP1((251-273 aa))) were synthesized. The synthetic peptides corresponding to bmZP1 were conjugated with diphtheria toxoid. Immunization of female BALB/cJ mice with the above conjugates and CSP-bmZP3((334-343 aa)) peptide led to the generation of an adequate antibody response against the respective zona peptide. Antibodies against bmZP1((251-273 aa)) and CSP-bmZP3((334-343 aa)) recognized bonnet monkey and human zona pellucida in an indirect immunofluorescence assay. Further, these antibodies when tested independently or in combination also significantly inhibited the binding of human spermatozoa to zona pellucida in a hemizona assay. These studies will further help in the design of synthetic peptide immunogens comprising of multiple B cell epitope from different zona proteins for better immunocontraceptive efficacy.

Seizures in the newborn

Seizures in the newborn period constitute a medical emergency. Subtle seizures are mild paroxysmal alterations in motor or autonomic activity and are unique to the neonatal period. They are likely to be missed or confused with benign movements observed commonly in preterm children. Focal clonic seizures have a better prognosis as compared to myoclonic seizures for long-term neuro-developmental outcome. Seizures due to sub-arachnoid hemorrhage and late onset hypocalcemia carry a better prognosis as compared to seizures due to hypoglycemia, meningitis and cerebral malformations. Hypoglycemia and hypocalcemia are common causes and should be excluded in all neonates with seizures. Multiple etiologies can co-exist in neonatal seizures and a comprehensive approach for management of neonatal seizures has been described.

Palladium-catalyzed heteroannulation leading to heterocyclic structures with two heteroatoms: a highly regio- and stereoselective synthesis of (Z)-4-alkyl-2-alkyl(aryl)idene-3,4-dihydro-2H-1,4-benzoxazines and (Z)-3-alkyl(aryl)idene-4-tosyl-3,4-dihydro-2H-1,4-benzoxazines

A highly convenient method has been developed for the synthesis of (Z)-4-alkyl-2-alkyl(aryl)idene-3,4-dihydro-2H-1,4-benzoxazines 9 and (Z)-3-alkyl(aryl)idene-4-tosyl-3,4-dihydro-2H-1,4-benzoxazines 34-38 through palladium-copper-catalyzed reactions. Aryl halides 7 reacted with 2-[N-alkyl(benzyl)-N-prop-2'-ynyl]aminophenyl tosylate 6 in the presence of (PPh3)2PdCl2 (3 mol %), CuI(5 mol %) in triethylamine at room temperature to yield 2-[N-alkyl(benzyl)-N-(3-aryl-prop-2'-ynyl)]-aminophenyl tosylates 8 in extremely good yields (72-96%). The latter could then be cyclized with KOH in ethanol-water to Z-9 in a highly regio- and stereoselective manner. Similarly, palladium-copper-catalyzed reaction of 2-(prop-2'-ynyloxy)aniline (21) with aryl iodides 7 led to 22-26 which after tosylation and cyclization with cuprous iodide in CH3CN in the presence of K2CO3 and Bu4-NBr led to the (Z)-3-alkyl(aryl)idene-4-tosyl 3,4-dihydro-2H-1,4-benzoxazines 34-38 in good overall yields. The Z-stereochemistry of the products was established from 1H NMR spectra, 3JCH values (between vinylic proton and methylenic carbon of the heterocyclic ring), NOE experiments, and X-ray analysis. The method was also found to be suitable for the synthesis of bis(benzoxazinylated) derivatives 17, 39, and 2-alkyl-3,4-dihydro-2H-1,4-benzoxazines 18. Our method for the synthesis of 3,4-dihydro-2H-1,4-benzoxazines is highly efficacious, using easily available starting materials under very mild conditions. Also the synthesis of some novel 5-substituted uracil derivatives 40 and 41 containing the benzoxazinyl moiety and of potential biological interest is being reported.

Megalourethra: a report of four cases and review of the literature

Megalourethra is a rare congenital anomaly characterized by severe dilatation of the penile urethra. Four cases of congenital megalourethra were seen at Sir Padampat Mother and Child Health Institute, Jaipur, during the last 10 years. Three cases of scaphoid megalourethra had no other associated congenital anomalies and were treat-ed successfully without any complications, while one patient with a fusiform megalourethra had severe associated congenital anomalies and died. These cases are reported with a review of the literature.