A critical role for inducible nitric oxide synthase in host survival following coxsackievirus B4 infection

Coxsackieviral infections have been linked etiologically to multiple diseases. The serotype CB4 is associated with acute pancreatitis and autoimmune type 1 diabetes. To delineate the mechanisms of host survival after an acute infection with CB4 (strain E2), we have investigated the role of nitric oxide (NO), generated by the inducible form of nitric oxide synthase (NOS2), in viral clearance and pancreatic beta-cell maintenance. Mice deficient in NOS2 (NOS2-/- mice) and their wild-type (wt) counterparts were injected with CB4, after which both groups developed severe pancreatitis, hepatitis, and hypoglycemia within 3 days. Within 4 to 7 days postinfection (p.i.), most of the NOS2-/- mice died and at a strikingly higher mortality rate than wt mice. Histological examination of pancreata from both infected NOS2-/- and infected wt mice revealed early and complete destruction of the pancreatic acinar tissue, but intact, insulin-stained islets. When examined up to 8 weeks p.i., neither surviving NOS2-/-mice nor surviving wt mice developed hyperglycemia. However, the clearance of infectious CB4 was different between the mice. The spleens of NOS2-/- survivors were cleared of infectious virus with kinetics similar to that of wt mice, but the livers, pancreata, kidneys, and hearts of the NOS2-/- groups cleared virus more slowly than those of the wt group. This delayed clearance was particularly prominent in the livers of infected NOS2-/- mice, which also showed prolonged histopathological features of viral hepatitis. Taken together, this outcome suggests that NOS2 (and NO) is not required for the prevention of pancreatic beta-cell depletion after CB4 infection. Instead the critical actions of NOS2 apparently occur early in the host immune response, allowing mice to survive and clear virus. Moreover, the data support the existence of an organ-specific dependency on NO for a rapid clearance of CB4.     

Toxicity of copper on marine diatoms,Chaetoceros calcitrans and Nitzchia closterium from Cochin estuary,India

The effects of copper (Cu) toxicity on the growth, pigments, protein, carbohydrate, lipid and antioxidant enzyme activities of two endemic microalgae, Chaetoceros calcitrans and Nitzchia closterium from Cochin estuary were studied and compared. The 96?h median inhibition concentration (IC₅₀) of Cu for C. calcitrans was 143.8?µg?L^?1 and that for N. closterium was 204.5?µg?L^?1. No observable effect concentration (NOEC), lowest observable effect concentration (LOEC) and chronic value of Cu on C. calcitrans were 17.93?µg?L^?1, 31.91?µg?L^?1and 24.92?µg?L^?1 respectively, whereas that for N. closterium were 18.35?µg?L^?1, 36.04?µg?L^?1 and 27.2?µg?L^?1 respectively. Chlorophyll a and c showed significant variation from the control at NOEC in both species. Carotenoid content showed significant increase at LOEC. The chlorophyll a/c ratio significantly decreased at NOEC and LOEC of N. closterium. In N. closterium catalase (CAT) activity showed significant increase at NOEC and LOEC, but in C. calcitrans it varied significantly above LOEC. Protein content showed a significant decrease at NOEC of C. calcitrans. No significant variation was observed for N. closterium. Carbohydrate showed significant variation between the species at NOEC. Lipid content varied significantly at NOEC of C. calcitrans. Chaetoceros calcitrans was observed to be more sensitive to copper toxicity than N. closterium. The metal stress tolerance mechanism of N. closterium and its bioremediation capacity can be established in further studies. This study also provides an insight on the biochemical changes that happened at NOEC.

     

A chemically labeled cytotoxic agent: Two-photon fluorophore for optical tracking of cellular pathway in chemotherapy

Chemotherapy is commonly used in the treatment of cancers. However, the mechanism of action of many of these agents is not well understood. We present the synthesis of a two-photon fluorophore (C625) and its biological application when chemically linked to a chemotherapeutic agent (AN-152). By using two-photon laser-scanning microscopy, the drug:fluorophore conjugate can be observed directly as it interacts with receptor-positive cell lines. The results of this project visually show the receptor-mediated entry of AN-152 into the cell cytoplasm and subsequently into the nucleus. These observations will allow for better understanding of the drug's therapeutic mechanism, which is a subject of ongoing research aimed at improving present methods for cancer therapy.     

Masked comparison of trypan blue stain and potassium hydroxide with calcofluor white stain in the microscopic examination of corneal scrapings for the diagnosis of microbial keratitis

Purpose:To evaluate the efficacy of trypan blue in direct microscopic examination of corneal scrapings in the diagnosis of non-viral microbial keratitis.Methods:In a prospective, interventional, masked study, 82 consecutive patients were investigated. Direct microscopic examination of the corneal scrapings involved three smears stained with potassium hydroxide with calcofluor white (KOH + CFW), Gram stain (not analyzed), and trypan blue stain and culture for bacteria, fungus, and Acanthamoeba. While KOH + CFW stained slides were examined under a fluorescence microscope, trypan blue-stained slides were examined by two microbiologists (masked to KOH + CFW and culture results) under normal light microscopy. Thirty samples were reexamined for interobserver and intraobserver variability.Results:Out of 82 samples, fungal/fungus-like elements were seen in 48 (58.5%) in KOH + CFW and 38 (46.3%) in trypan blue stain. One microsporidial case, detected in KOH + CFW was negative in trypan blue stain (culture not done). Fungal growth was positive in 23 out of 81 (28.3%) cases cultured, single bacterial species in 18 (22.2%), Pythium insidiosum in three, mixed bacteria and fungus/Pythium in 7 (8.6%), Acanthamoeba in none and 30 (37.0%) samples were sterile. With culture as gold standard, the respective sensitivity (84.9%, 75.7%) and specificity (90.9%, 68.2%) of KOH + CFW stain and trypan blue stain were comparable (p = 0.16, P = 0.06). The interobserver linear weighted kappa score between the two microbiologists was 1.00 while it was 0.86 for intraobserver agreement.Conclusion:Trypan blue stain, an easily available dye to ophthalmologists, is highly efficacious in the diagnosis of fungal keratitis.     

Repeatability and agreement of central corneal thickness measurement with non-contact methods: a comparative study

Purpose

To compare the central corneal thickness (CCT) measurements and reliability of RTVue XR-100 anterior segment optical coherence tomography (AS-OCT), AL-scan optical biometer and Schwind Sirius anterior segment analysis system.

Methods

The CCT was measured in one hundred and twenty-seven eyes of 127 healthy subjects with AS-OCT, AL-scan and Sirius system. Mean CCT was compared among the instruments, and the level of agreement was assessed using Bland–Altman plots. One eye each of 30 subjects was randomly assigned for intrasession intraoperator and interoperator repeatability which was assessed using coefficient of variation and intraclass correlation coefficient.

Results

Mean CCT with AS-OCT, AL-scan and Sirius system was 496.72 ± 32.75, 507.43 ± 33.54 and 512.08 ± 33.1 µm, respectively. There was no statistically significant difference between AL-scan and Sirius system (p = 0.26). Significant difference was found between AS-OCT/AL-scan (p = 0.01) and AS-OCT/Sirius system (p < 0.0001). Bland–Altman analysis showed a high level of agreement between AL-Scan/Sirius system (Mean difference ?4.6 µm) and a low level of agreement between AS-OCT/AL-scan (Mean difference ?10.7 µm) and OCT/Sirius system (Mean difference ?15.4 µm).

Conclusions

AS-OCT underestimated CCT measurements when compared to other two devices in healthy subjects. Hence, one must be cautious when analyzing the results from different machines and should be aware that the measurement values are not interchangeable.

     

Self Tapping Screws v/s Erich Arch Bar for Inter Maxillary Fixation: A Comparative Clinical Study in the Treatment of Mandibular Fractures

Introduction and Objective  

Numerous methods have been described for achievement of Intermaxillary fixation in the treatment of fractures of facial skeleton. Conventional methods like Erich arch bars and eyelet wires are currently most common methods for achieving intermaxillary fixation (IMF), but they have their own disadvantages. Since 1989, IMF using intraoral self tapping IMF screws has been introduced for treatment of mandibular fractures. The aim of this work was to compare the efficacy, advantages, disadvantages indications and potential complications associated with Erich archbar v/s self tapping IMF screws in the management of mandibular fractures.     

Microwave-mediated synthesis of triazolothiadiazoles as anti-inflammatory,analgesic, and anti-oxidant agents

Efficient approach to the synthesis of a series of triazolothiadiazole analogs of ibuprofen has been carried out using microwave energy. Thus a series of 1,2,4-triazolo[3,4-b]-thiadiazoles 5 were synthesized starting from 4-amino-3-[1-(4-isobutylphenyl)ethyl]-5-mercapto-1,2,4-triazole 3 and different aromatic acids using phosphorous oxychloride as cyclizing agent by microwave and conventional method. Microwave irradiation reduces both time and reaction endeavors along with reduced amount of phosphorous oxychloride. In addition, preliminary results of the biological evaluation of these compounds are also reported and they found to exhibit significant antioxidant, anti-inflammatory, and analgesic activities with reduced ulcerogenicity.     

Association of endothelial nitric oxide synthase gene T-786C promoter polymorphism with gastric cancer

AIM: To investigate the role of endothelial nitric oxide synthase -786T > C promoter polymorphism in the etiology of gastric cancer (GC).METHODS: A total of 150 GC patients and 150 control subjects were included in the study. The information on demographic features was elicited with an informed consent from all the patients and control subjects using a structured questionnaire. Helicobacter pylori (H. pylori) infectivity status was tested in antral biopsies from all the subjects by rapid urease test following the method of Vaira et al. Genomic DNA was isolated from whole blood samples following the salting out method of Lahiri et al. Genotype analysis of the rs2070744 polymorphism was carried out by allele-specific polymerase chain reaction method. The genotypes were determined based on the appearance of bands on an agarose gel stained with ethidium bromide under ultraviolet gel documentation with the help of 100 bp ladder. Odds ratios and corresponding 95%CIs were determined using java stat online software.RESULTS: There was a significant difference in the distribution of C allele (C vs T; P = 0.000, OR = 5.038) in patient group compared to the control subjects exhibiting a fivefold increased risk for GC. When the T/T and C/C genotypes were compared, there was an enhanced GC risk for individuals with C/C genotype (T/T vs C/C; P = 0.000). Among the demographic factors, smoking and alcoholism were the common risk factors in patients compared to the control subjects (P < 0.05). Patients with smoking and alcoholism developed cancer even in heterozygous T/C condition (smoking: P = 0.020 and alcoholism: P = 0.005). Individuals with H. pylori infection showed seven fold increased risk for cancer. All the patients with C/C genotype revealed a significant association between H. pylori infection and GC. Among the patients 2.4% of them revealed familial incidence of GC. No significant difference was noticed between cases and controls with regard to consanguinity (P = 0.473).CONCLUSION: The Present data suggest that eNOS-786 C/C genotype and C allele may be considered as potential risk factors in patients with GC.