Multiscale analyses reveal native-like lamellar bone repair and near perfect bone-contact with porous strontium-loaded bioactive glass

The efficient healing of critical-sized bone defects using synthetic biomaterial-based strategies is promising but remains challenging as it requires the development of biomaterials that combine a 3D porous architecture and a robust biological activity. Bioactive glasses (BGs) are attractive candidates as they stimulate a biological response that favors osteogenesis and vascularization, but amorphous 3D porous BGs are difficult to produce because conventional compositions crystallize during processing. Here, we rationally designed a porous, strontium-releasing, bioactive glass-based scaffold (pSrBG) whose composition was tailored to deliver strontium and whose properties were optimized to retain an amorphous phase, induce tissue infiltration and encourage bone formation. The hypothesis was that it would allow the repair of a critical-sized defect in an ovine model with newly-formed bone exhibiting physiological matrix composition and structural architecture. Histological and histomorphometric analyses combined with indentation testing showed pSrBG encouraged near perfect bone-to-material contact and the formation of well-organized lamellar bone. Analysis of bone quality by a combination of Raman spectral imaging, small-angle X-ray scattering, X-ray fluorescence and focused ion beam-scanning electron microscopy demonstrated that the repaired tissue was akin to that of normal, healthy bone, and incorporated small amounts of strontium in the newly formed bone mineral. These data show the potential of pSrBG to induce an efficient repair of critical-sized bone defects and establish the importance of thorough multi-scale characterization in assessing biomaterial outcomes in large animal models.

Functional organ preservation with definitive chemoradiotherapy for T4 laryngeal squamous cell carcinoma

BACKGROUND

Randomized trials established chemoradiotherapy as standard treatment for advanced laryngeal cancer. Patients with large-volume T4 disease (LVT4) were excluded from these trials. The purpose of this study was to report T4 laryngeal cancer patient outcome, including those with LVT4 disease, treated with chemoradiotherapy.

PATIENTS AND METHODS

This study is a retrospective subset analysis of 32 patients with T4 laryngeal carcinoma including LVT4 tumors treated on three consecutive protocols investigating paclitaxel (Taxol), 5-fluorouracil, hydroxyurea, and 1.5-Gy twice daily (BID) radiotherapy (TFHX).

RESULTS

Median follow-up is 43 months. Four-year locoregional control (LRC), disease-free survival (DFS), overall survival (OS), and laryngectomy-free survival (LFS) was 71%, 67%, 53%, and 86%, respectively. Four patients required laryngectomy for recurrent or persistent disease. Of disease-free patients with >or=1 year follow-up, 90% demonstrated normal or understandable speech. None required laryngectomy for complications. Among LVT4 patients, 4-year LRC, DFS, OS, and LFS was 71%, 65%, 56%, and 81%, respectively. Induction chemotherapy improved 4-year LRC (90% versus 46%, P = 0.03) and DFS (84% versus 42%, P = 0.03).

CONCLUSIONS

Promising control and functional outcomes are achieved with TFHX for T4 laryngeal patients. LVT4 disease had outcomes similar to patients with less advanced disease treated on Radiation Therapy Oncology Group 91-11. Induction chemotherapy improved outcomes, warranting further investigation.

Effect of HCl on the doping and shape control of silicon nanowires

The introduction of hydrogen chloride during the in situ doping of silicon nanowires (SiNWs) grown using the vapor-liquid-solid (VLS) mechanism was investigated. Compared with non-chlorinated atmospheres, the use of HCl with dopant gases considerably improves the surface morphology of the SiNWs, leading to extremely smooth surfaces and a greatly reduced tapering. Variations in the wire diameter are massively reduced for boron doping, and cannot be measured at 600 °C for phosphorous over several tens of micrometers. This remarkable feature is accompanied by a frozen gold migration from the catalyst, with no noticeable levels of gold clusters observed using scanning electron microscopy. A detailed study of the apparent resistivity of the NWs reveals that the dopant incorporation is effective for both types of doping. A graph linking the apparent resistivity to the dopant to silane dilution ratio is built for both types of doping and discussed in the frame of the previous results.

Identification of glutamate ABC-Transporter component in Clostridium perfringens as a putative drug target

Clostridium perfringens is an anaerobic pathogen known to cause vast number of diseases in mammals and birds. Various toxins and hydrolysing enzymes released by the organism are responsible for the necrosis of soft tissues. Due to serious safety issues associated with current vaccines against C. perfringens, there is a need for new drug or vaccine targets. C. perfringens is extremely dependent on its host for nutrition which can be targeted for vaccine development or drug design. Therefore, it is of interest to identify the unique transport systems used by C. perfringens involved in uptake of essential amino acids that are synthesized by the host, so that therapeutic agents can be designed to target the specific transport systems. Use of bioinformatics tools resulted in the identification of a protein component of the glutamate transport system that is not present in the host. Analysis of the conservation profile of the protein domain indicated it to be a glutamate binding protein which also stimulates the ATPase activity of ATP Binding Cassettes (ABC) transporters. Homology modelling of the protein showed two distinct lobes, which is a characteristic of substrate binding proteins. This suggests that the carboxylates of glutamate might be stabilized by electrostatic interactions with basic residues as is observed with other binding proteins. Hence, the homology model of this potential drug target can be employed for in silico docking studies by suitable inhibitors.

Clostridium perfringens beta toxin DNA prime-protein boost elicits enhanced protective immune response in mice

Clostridium perfringens beta toxin (CPB) is the primary pathogenic factor responsible for necrotic enteritis in sheep, cattle and humans. Owing to rapid progression of the disease, vaccination is the only possible recourse to avoid high mortality in animal farms and huge economic losses. The present study reports evaluation of a cpb gene-based DNA vaccine encoding the beta toxin of C. perfringens with homologous as well as heterologous booster strategy. Immunization strategy employing heterologous booster with heat-inactivated rCPB mounted stronger immune response when compared to that generated by homologous booster. Antibody isotyping and cytokine ELISA demonstrated the immune response to be Th1-biased mixed immune response. While moderate protection of immunized BALB/c and C57BL/6 mice against rCPB challenge was observed with homologous booster strategy, heterologous booster strategy led to complete protection. Thus, beta toxin-based DNA vaccine using the heterologous prime-boosting strategy was able to generate better immune response and conferred greater degree of protection against high of dose rCPB challenge than homologous booster regimen, making it an effective vaccination approach against C. perfringens beta toxin.

Immunization with recombinant fusion of LTB and linear epitope (40-62) of epsilon toxin elicits protective immune response against the epsilon toxin of Clostridium perfringens type D

Epsilon toxin (Etx) produced by Clostridium perfringens types B and D, a major causative agent of enterotoxaemia causes significant economic losses to animal industry. Conventional vaccines against these pathogens generally employ formalin-inactivated culture supernatants. However, immunization with the culture supernatant and full length toxin subjects the animal to antigenic load and often have adverse effect due to incomplete inactivation of the toxins. In the present study, an epitope-based vaccine against Clostridium perfringens Etx, comprising 40-62 amino acid residues of the toxin in translational fusion with heat labile enterotoxin B subunit (LTB) of E. coli, was evaluated for its protective potential. The ability of the fusion protein rLTB.Etx_40-62 to form pentamers and biologically active holotoxin with LTA of E. coli indicated that the LTB present in the fusion protein retained its biological activity. Antigenicity of both the components in the fusion protein was retained as anti-fusion protein antisera detected both the wild type Etx and LTB in Western blot analysis. Immunization of BALB/c mice with the fusion protein resulted in a significant increase in all isotypes, predominantly IgG1, IgG2a and IgG2b. Anti-fusion protein antisera neutralized the cytotoxicity of epsilon toxin both in vitro and in vivo. Thus, the results demonstrate the potential of rLTB.Etx_40-62 as a candidate vaccine against C. perfringens.

Electrostatically Doped Silicon Nanowire Arrays for Multispectral Photodetectors

Nanowires have promising applications as photodetectors with superior ability to tune absorption with morphology. Despite their high optical absorption, the quantum efficiencies of these nanowire photodetectors remain low due to difficulties in fabricating a shallow junction using traditional doping methods. As an alternative, we report nonconventional radial heterojunction photodiodes obtained by conformal coating of an indium oxide layer on silicon nanowire arrays. The indium oxide layer has a high work function which induces a strong inversion in the silicon nanowire and creates a virtual p-n junction. The resulting nanowire photodetectors show efficient carrier separation and collection, leading to an improvement of quantum efficiency up to 0.2. In addition, by controlling the nanowire radii, the spectral responses of the In₂O₃/Si nanowire photodetectors are tuned over several visible light wavelengths, creating a multispectral detector. Our approach is promising for the development of highly efficient wavelength-selective photodetectors.

Cerebral venous congestion during cardio-pulmonary bypass: role of bispectral index monitoring

A 58-year-old male patient was posted for double valve replacement under hypothermic cardiopulmonary bypass (CPB). During aortic cross-clamp (AXC), the central venous pressure (CVP) was found to have increased to 22 mmHg. After 4 minutes of sustained increase in CVP, burst suppression (SR) started increasing. After 5 min of increase in SR, bispectral index (BIS) declined rapidly to 17. Propofol infusion was stopped and re-evaluation of signs of facial congestion showed changes to that effect. The perfusionist noted steadily decreasing venous return. As soon as the superior vena cava (SVC) cannula was withdrawn by 3 cm, CVP immediately declined to 6 mmHg. The venous return in the CPB reservoir normalized and BIS returned to 42 after a transient rise to a maximum of 58 and SR decreased to 0 within 2 min of repositioning of the venous cannula. The patient was successfully extubated after 7 hours without any sequelae.

Dynamic selection of visible wavelengths using resonant TiO2 nanostructures

All-dielectric nanoarrays have strong electromagnetic resonances with various interesting applications and are tuned by adjusting their geometrical parameters. However, their optical properties are permanently encoded during fabrication. This study presents robust dynamically tunable all-dielectric nanoresonators for controllable, reversible, and reproducible color filtering. Our design uses an array of TiO2 nanodiscs embedded in a transparent, stretchable polydimethylsiloxane (PDMS) membrane and exhibits a narrow spectral response due to Mie magnetic and electric dipole resonances hybridized with the TiO2 nanodiscs lattice modes. By mechanically stretching the PDMS membrane, the pitch of the TiO2 nanodiscs was increased and the spectral location of the resonances was altered. Additionally, an optically asymmetric structure was fabricated by partially embedding TiO2 nanodiscs in PDMS. Thus, the magnitude of the Rayleigh anomaly diffraction, which could interrupt the dipole resonances, was reduced. Our design has sharp, frequency-tunable resonances in the visible spectrum, and we demonstrated dynamic tunability by stretching the metasurfaces.

Molecular docking analysis of Clostridium perfringens beta toxin model with potential inhibitors from the ZINC database

Beta toxin from Clostridium perfringens after being secreted in gut is capable of causing necrotic enteritis in humans and several other animal species and does not respond to routinely used antibiotics. Therefore, there is a need to design an effective inhibitor for the Clostridium perfringens beta toxin (CPB) using cutting edge drug discovery technologies. Hence, potential CPB inhibitors were identified using computer aided screening of compounds from the ZINC database. Further, we document the molecular docking analysis of Clostridium perfringens beta toxin model (that revealed 4 binding pockets, A-D) with the identified potential inhibitors. We show that ZINC291192 [N-[(1-methylindol-3-yl) methyl eneamino]-7,10-dioxabicyclo[4.4.0]deca-2,4,11-triene-8- carboxamide] has optimal binding features with calculated binding energy of -10.38 kcal/mol and inhibition constant of 24.76 nM for further consideration.

A simple synthetic liquid medium for development of yeast and mycelial form of pathogenic species of Candida

Thirty two known strains of Candida species were used for evaluation of glucose, serine, ornithine, methionine, GSOM medium and its comparison with Lee's medium for the production of yeast and mycelial phase at different temperatures and on prolonged incubation. No mycelial form was observed when various Candida species in GSOM and Lee's medium were incubated at 25 degrees C up to 72 hours. Percentage of mycelial forming cells of Candida species were more in GSOM medium than Lee's medium in 48 hours at 37 degrees C. Among various species of Candida, albicans and C. parapsilosis showed maximum mycelium formation. GSOM medium can be used for growing Candida species particularly C. albicans in mycelial phase.

Use of Tranexamic Acid in SARS-COV-2: Boon or Bane?

The devastating pandemic of SARS-CoV-2 (COVID-19) began in Wuhan, China, and spread rapidly through most parts of the world in the second half of 2020. The air droplet spread of SARS-CoV-2 is of great global health concern as it is potentially fatal. Various drugs and treatment modalities have been tried to date, but none have been found to be definitive. Tranexamic acid (TXA) is commonly used in pigmentary disorders in dermatology due to its ability to reduce melanocyte tyrosinase activity. It also possesses anti-fibrinolytic and anti-inflammatory properties, which have been observed to suppress the cytokine storm and modulate coagulopathy in patients suffering from COVID-19. TXA, when administered early, has been effective in decreasing the severity of symptoms in COVID-19 patients, but on the contrary, it has also been associated with life-threatening thrombosis when given as a single drug.

Morphological identification of Candida species on glucose agar, rice extract agar and corn meal agar with and without Tween-80

A comparative study for the identification of 32 known strains of Candida species on the basis of morphology on glucose agar, rice extract agar and corn meal agar with and without Tween 80 revealed that when Tween 80 is incorporated in the media identification is possible for 96.8% of the species within 48 hours on rice extract agar and for 96.8% of the species within 48 hours on rice extract agar and for 90.6% of the species on glucose agar. The germ tubes and chlamydospores were also produced more on rice extract agar than on 0.1% glucose agar. Rice extract agar with Tween 80 can be used as single medium for morphologic identification of Candida species. The inoculated medium is first incubated at 37 degrees C for 3 hours and examined for germ tube formation and then incubated at 25 degrees C for 24 to 72 hours and examined for appearance of chlamydospores and mycelial morphology.

High Dose Methylprednisolone: Effective in Pregnancy Associated Post-splenectomy Refractory Chronic Immune Thrombocytopenic Purpura

We present a case of 23 years multigravid woman (G2P0+1) with chronic idiopathic thrombocytopenic purpura (ITP), refractory to treatment in forms of oral steroid, dapsone, azathioprine and splenectomy. She presented to the hospital in third trimester of pregnancy, with reduced platelet counts and purpuric rashes over abdomen and both upper extremeties. There was a past history of spontaneous abortion at 18 weeks. The patient responded to intravenous high dose methylprednisolone (HDMP) infusion leading to delivery of full term male baby. The baby also required treatment for thrombocytopenia with intravenous immunoglobulin (IVIG). This case lays down the importance of HDMP in form of using it effectively in managing acute crisis of low platelet counts in pregnant patients with ITP refractory to splenectomy. DOI: http://dx.doi.org/10.3126/njog.v9i1.11192 NJOG 2014 Jan-Jun; 2(1):64-66

Clinicomycological study of tinea capitis in desert district of Rajasthan

The clinicomycological study was conducted on 200 cases of Tinea capitis in Jodhpur. Incidence of tinea capitis among superficial mycoses was 4.43 and male to female ratio being 1.8:1. Majority of patients were from urban area (88%) and positive family history of dermatophytoses was present in 29% of cases. Majority of patients attended hospital OPD from July to October (39.%%) and January to April (49%). Persons using mustard oil as hair applicant had single or less lesions as compared to individual using other oil. Endothrix involvement of hair was seen in 78% cases and Trichophyton violaceum was predominant fungus (88.5%) recovered on culture.

Demonstration of IgG subclass (IgG1 and IgG3) in patients with positive direct antiglobulin tests

Serologic characterization of autoantibodies helps in the management and monitoring of the course of autoimmune hemolytic anemia (AIHA). The purpose of this study was to evaluate gel centrifugation test (GCT) cards for immunoglobulin G (IgG) titer and determination of IgG subclasses IgG1 and IgG3 and their influence on hemolysis. Eighty direct antiglobulin test (DAT)-positive patients were examined with the help of GCT cards for IgG titer and IgG subclasses. The results were correlated with the presence and absence of hemolysis. A statistically significant (p < 0.005) association of hemolysis with increasing anti-IgG titer was observed. When IgG titer was 30 or less, 28 (50.91%) patients had no hemolysis, whereas 15 (93.75%) patients had features of hemolysis when titer was at least 300. Statistically significant (p < 0.005) association of subclass of IgG (IgG1, IgG3) coating the red blood cells with intravascular hemolysis was also seen. Twenty-nine (80.56%) patients had evidence of hemolysis when IgG1 or IgGl-IgG3 both were present. Gel technology is helpful to demonstrate red blood cell-bound autoantibodies and their characterization with regard to class, subclass, and titer. This information is useful to identify patients with AIHA who are at risk of severe hemolysis with adverse prognosis.

Molecular docking analysis of P2X7 receptor with the beta toxin from Clostridium perfringens

Clostridium perfringens beta-toxin (CPB) is linked to necrotic enteritis (over proliferation of bacteria) in several species showing cytotoxic effect on primary porcine endothelial and human precursor immune cells. P2X7 receptor on THP-1 cells is known to bind CPB. This is critical to understand the mechanism of pore formation for effective drug design. The structure of CPB and P2X7 receptor proteins were modeled using standard molecular modeling procedures (I-TASSER and Robetta server). This is followed by protein-protein docking (HADDOCK server) to study their molecular interaction. Interacting residues (19 residues from CPB and 21 residues from P2X7) were identified using the PISA server. Thus, we document the molecular docking analysis of P2X7 receptor with the beta toxin from Clostridium perfringens towards drug design and development of drugs to control necrotic enteritis.