Fiber-connectorized ultrafast-laser-inscribed K-band integrated optics beam combiner for the CHARA telescope array.

A fiber-connectorized K-band integrated-optics two-telescope beam combiner was developed for long-baseline interferometry at the CHARA telescope array utilizing the ultrafast laser inscription (ULI) technique. Single-mode waveguide insertion losses were measured to be ∼1.1d B over the 2-2.3 µm window. The development of asymmetric directional couplers enabled the construction of a beam combiner that includes a 50:50 coupler for interferometric combination and two ∼75:25 couplers for photometric calibration. The visibility of the bare beam combiner was measured at 87% and then at 82% after fiber-connectorization by optimizing the input polarization. These results indicate that ULI technique can fabricate efficient fiber-connectorized K-band beam combiners for astronomical purposes.

Rapid diagnosis of TB using Aptamer-based assays for Mycobacterium tuberculosis antigens in children and adolescents.

Background: Despite advances establishing microbiological evidence of tuberculosis (TB) is still a concern in children due to the limitation of availability of sample and predominance of extrapulmonary TB, there is unmet need for diagnostic tests which are low cost, rapid and sensitive and specific. Methods: This study evaluated the utility of aptamer-based assay for detecting mycobacterium tuberculosis antigens HspX and MPT 64 in rapid diagnosis of TB in children up to 18 years of age in a tertiary medical college. A total of 100 children were sequentially enrolled with presumptive pulmonary (n = 52 and extrapulmonary n = 48) TB based on clinico-radiological characteristics. The samples were evaluated with ALISA technique for TB antigens and compared with the results of ZN microscopy, GeneXpert and mycobacterial culture MGIT. Results: The enrolled children had mean age (11.7 + 4.4 years) with both pulmonary (n = 52) and extrapulmonary TB (n = 48). Our study results concluded poor results of smears (11% positivity, sensitivity: 17.7%, NPV: 42.7%) and better of GeneXpert (positivity: 42%, sensitivity of 67.4%, NPV: 65.5%) and culture (positivity 57%, sensitivity 91.9%, NPV 88.3%). HspX antigen by ALISA had comparable results (positivity: 49%, sensitivity: 62.9%; NPV: 54.9%). MPT 64 antigen by ALISA also had similar results (positivity: 45%, sensitivity: 58% and NPV 52, 3%). Sensitivity and specificity were higher in pulmonary TB compared to EPTB for both antigens. HspX antigen assay by ALISA and MPT 64 ALISA over existing microbiological diagnostic methods had additional of 13%. Conclusion: ALISA technique for mycobacterium antigens HspX and MPT 64 was rapid, low-cost test (1-3$/test) high sensitivity and specificity and comparable to currently available methods.

Recent Advances and a Roadmap to Aptamer-Based Sensors for Bloodstream Infections.

The present review is intended to describe bloodstream infections (BSIs), the major pathogens responsible for BSIs, conventional tests and their limitations, commercially available methods used, and the aptamer and nanomaterials-based approaches developed so far for the detection of BSIs. The advantages associated with aptamers and the aptamer-based sensors, the comparison between the aptamers and the antibodies, and the various types of aptasensors developed so far for the detection of bloodstream infections have been described in detail in the present review. Also, the future outlook and roadmap toward aptamer-based sensors and the challenges associated with the aptamer development have also been concluded in this review.

An Aptamer Linked Immobilized Sorbent Assay (ALISA) to Detect Circulatory IFN-α, an Inflammatory Protein among Tuberculosis Patients.

Dysregulation of IFN-α is the basis for pathogenesis of autoimmune as well as infectious diseases. Identifying inflammatory signatures in peripheral blood of patients is an approach for monitoring active infection. Hence, estimation of type I IFNs as an inflammatory biomarker to scrutinize disease status after treatment is useful. Accordingly, an Aptamer Linked Immobilized Sorbent Assay (ALISA) for the detection of IFN-α in serum samples was developed. Sixteen aptamers were screened for their ability to bind IFN-α. Aptamer IFNα-3 exhibited specificity for IFN-α with no cross-reactivity with interferons ß and γ and human serum albumin. The disassociation constant (Kd) was determined to be 3.96 ± 0.36 nM, and the limit of detection was ∼2 ng. The characterized IFNα-3 aptamer was used in ALISA to screen tuberculosis (TB) patients' sera. An elevated IFN-α level in sera derived from untreated TB patients (median = 0.31), compared to nontuberculous household contacts (median = 0.13) and healthy volunteers (median = 0.12), and further a decline in IFN-α level among treated patients (median = 0.13) were seen. The ALISA assay facilitates direct estimation of inflammatory protein(s) in circulation unlike mRNA estimation by real time PCR. Designing of aptamers similar to the IFNα-3 aptamer provides a novel approach to assess other inflammatory protein(s) in patients before, during, and after completion of treatment and would denote clinical improvement in successfully treated patients.

Phytochemicals as Dynamic Surface Ligands To Control Nanoparticle-Protein Interactions.

The rapid formation of the protein corona on to the nanoparticle (NP) surface is the key that confers biological identity to NPs and subsequently dictates their fate both in vitro and in vivo. Despite significant efforts, the inability to control the spontaneous interaction of serum proteins with the administered NPs remains a major constraint in clinical translation of nanomedicines. The ligands present on the NP surface offer promise in controlling their biological interactions; however, their influence on the NP-protein interaction is not well-understood. The current study investigates the potential of phytochemical-capped silver nanoparticles (AgNPs) toward allowing a control over NP interactions with the human serum albumin (HSA), the most abundant protein in the biological fluids. Specifically, we demonstrate the ability of curcumin (Cur) and epigallocatechin-3-gallate (EGCG) to independently act as reducing agents to produce phytochemical-capped AgNPs that show biologically desirable interactions with HSA. The key finding of our study is that the phytochemical-capped AgNPs initially interact with HSA more strongly compared to the citrate-stabilized AgNPs; however, the resultant NP-HSA complexes are less stable in the case of the former, which causes a lesser degree of changes in the protein conformation during interactions. Further, the choice of the phytochemical allows control over NP-HSA interactions, such that Cur- and EGCG-capped AgNPs interacted with HSA in a static versus dynamic manner, respectively. The diversity of the functional groups present in natural phytochemicals and their potential as in situ capping ligands during synthesis offer new opportunities in controlling the interactions of NPs with complex biological fluids, with implications in nanodiagnostics and nanomedicine.

Simple Methods and Rational Design for Enhancing Aptamer Sensitivity and Specificity.

Aptamers are structured nucleic acid molecules that can bind to their targets with high affinity and specificity. However, conventional SELEX (Systematic Evolution of Ligands by EXponential enrichment) methods may not necessarily produce aptamers of desired affinity and specificity. Thus, to address these questions, this perspective is intended to suggest some approaches and tips along with novel selection methods to enhance evolution of aptamers. This perspective covers latest novel innovations as well as a broad range of well-established approaches to improve the individual binding parameters (aptamer affinity, avidity, specificity and/or selectivity) of aptamers during and/or post-SELEX. The advantages and limitations of individual aptamer selection methods and post-SELEX optimizations, along with rational approaches to overcome these limitations are elucidated in each case. Further the impact of chosen selection milieus, linker-systems, aptamer cocktails and detection modules utilized in conjunction with target-specific aptamers, on the overall assay performance are discussed in detail, each with its own advantages and limitations. The simple variations suggested are easily available for facile implementation during and/or post-SELEX to develop ultrasensitive and specific assays. Finally, success studies of established aptamer-based assays are discussed, highlighting how they utilized some of the suggested methodologies to develop commercially successful point-of-care diagnostic assays.

Homocysteine Metabolism and Hematological Parameters in Early Stage of Phenytoin Treated Epileptic Children.

BACKGROUND: Long-term antiepileptic drug (AED) therapy has been associated with metabolic consequences that lead to an increase in risk of atherosclerosis in patients with epilepsy. Earlier published studies showed conflicting results about the levels of hematological parameters, serum homocysteine, folate, and vitamin B12, in epileptics treated with phenytoin monotherapy. Therefore, we evaluated homocysteine metabolism and hematological parameters in early stage of phenytoin treated epileptic children. METHODS: A total of 64 newly diagnosed epileptic children with mean age 10.09 ± 2.56 years were enrolled at the start of study. However, after 3 months follow up, the final total sample size was only 50 epileptic children. Fourteen children dropped out of study due to poor follow up. Serum homocysteine levels were measured by enzyme immunoassay method. Serum folate and vitamin B12 levels were estimated by Competitive Chemiluminescent Enzyme Immunoassay method. Hematological parameters were analysed by an automated hematology analyzer (Cell counter), Sysmex XT-1800i, using commercially available reagents. RESULTS: In our study the anthropometric and hematological parameters did not show any significant difference after phenytoin monotherapy as compared to before therapy in epileptic children. The serum homocysteine level in epileptic children was found to be significantly increased after phenytoin (PHT) monotherapy as compared to before therapy. Moreover, a highly significant decrease was observed in the serum folate and vitamin B12 levels after phenytoin monotherapy as compared to before therapy in epileptic children. CONCLUSIONS: Phenytoin monotherapy may cause a significant increase in the levels of serum homocysteine and a significant decrease in the serum folate and vitamin B12 levels in children with epilepsy, and the significant changes in above mentioned parameters occur early in the course of treatment. This could be responsible for a higher prevalence of cardiovascular incidents in epileptic children taking phenytoin monotherapy. Therefore, it may be useful to do early screening and treatment of increased serum homocysteine levels in epileptic children under phenytoin monotherapy to prevent atherosclerosis and its complications. Hematological parameters should also be strictly monitored regularly in individuals administered with PHT monotherapy. If there are persistent alterations, the administration of the drugs should be discontinued.

Natural Antioxidant Vitamins Status in Pregnancies Complicated with Intrauterine Growth Restriction.

BACKGROUND: The weight of the infant at birth is a powerful predictor of infant growth and survival and is dependent on maternal health and nutrition during pregnancy. Pregnant women have a defense mechanism against increased oxidative stress composed of antioxidant enzymes and natural antioxidant vitamins like vitamin C and E. Therefore, we evaluated whether differences exist in serum levels of vitamin C and E in pregnant women complicated with intrauterine growth restriction (IUGR). METHODS: This study was done in 180 pregnant women admitted in hospital for delivery. Blood samples were collected and stored at -70°C until analysis. Among 180 pregnant women 150 were identified as IUGR pregnant women according to the weight of the infant and the remaining 30 normal healthy pregnant women as controls. Blood hemoglobin and serum vitamin C and E levels were measured in both groups. RESULTS: The mean hemoglobin concentration was significantly decreased (p< 0.001) in IUGR pregnant women (8.92 ± 1.35 g/dL) as compared to the normal healthy pregnant women (10.51 ± 1.04 g/dL) in our study. The serum concentration of vitamin C in the group of pregnant women with IUGR was 0.54 ± 0.15 mg/dL, whereas in the group of normal healthy pregnant women it was 0.91 ± 0.23 mg/dL. The serum vitamin E level in the normal healthy pregnant women group was 1.22 ± 0.35 mg/dL and 0.65 ± 0.24 mg/dL in IUGR pregnant women group. The serum vitamin C and E level in IUGR pregnant women group was found to be significantly decreased as compared to the normal healthy pregnant women group. CONCLUSIONS: The study indicates the importance of natural antioxidants vitamin C and E against increased oxidative stress in pregnancies complicated with IUGR. Therefore, it may be useful to measure serum vitamin C and E levels in IUGR pregnant women. This study suggests further research to investigate the role of these natural antioxidant vitamins in fetal growth at various gestation stages.

Serum Homocysteine, Folate, and Vitamin B12 Levels in Carbamazepine Treated Epileptic Children.

BACKGROUND: Antiepileptic drugs (AEDs) have been associated with metabolic consequences that lead to an increase in risk of atherosclerosis in patients with epilepsy. Therefore, we evaluated whether differences exist in homocysteine, folate, and vitamin B12 levels in children receiving carbamazepine (CBZ) monotherapy. METHODS: A total of 58 newly diagnosed epileptic children with ages ranging from 2 to 15 years were enrolled at the start of study. However, after 3 months follow up, the final total sample size was only 50 epileptic children. Eight children dropped out of the study due to poor follow up. Serum homocysteine levels were measured by enzyme immunoassay method. Serum folate and vitamin B12 levels were estimated by Competitive Chemiluminescent Enzyme Immunoassay method. RESULTS: The serum homocysteine level in epileptic children was found to be significantly increased after carbamazepine (CBZ) monotherapy as compared to before therapy. Moreover, a highly significant decrease was observed in the serum folate and vitamin B12 levels, after carbamazepine monotherapy as compared to before therapy in epileptic children. CONCLUSIONS: Carbamazepine monotherapy may cause a significant increase in the levels of homocysteine and a significant decrease in the levels of serum folate and vitamin B12 in children with epilepsy, significant changes in above mentioned parameters occurring early in the course of treatment. The atherogenic effect of increased serum homocysteine level is well established, and patients under carbamazepine monotherapy should be monitored for possible atherogenic effects. Therefore, it may be useful to measure serum homocysteine, folate, and vitamin B12 concentrations routinely in children with epilepsy taking carbamazepine monotherapy and be treated when their levels are found to be disturbed.

A study on metabolic prowess of Pseudomonas sp. RPT 52 to degrade imidacloprid, endosulfan and coragen.

A bacterial strain identified as Pseudomonas sp. RPT 52, was isolated from an agricultural field by soil enrichment technique. The bacterial strain was able to metabolize three different chlorinated pesticides; imidacloprid, endosulfan and coragen (belonging to neonicotinoid, organochlorine and anthranillic diamide categories, respectively). RPT 52 was able to degrade 46.5%, 96.6%, 92.7% and 80.16% of 0.5 mM of imidacloprid, endosulfan α, endosulfan ß and coragen, respectively, in minimal medium over a period of 40 h, when provided as sole source of carbon and energy. Degradation kinetics showed that imidacloprid, endosulfan α and endosulfan ß followed first order kinetics whereas coragen followed zero order kinetics. Toxicity studies show reduction in toxicity of the parent compound when degraded by RPT 52. Laboratory scale, soil microcosm studies showed that strain RPT 52 is a suitable candidate for bioremediation of endosulfan and coragen contaminated sites. Thus, RPT 52 holds potential for toxicity reduction in the affected environment.

Moving forward in plant food safety and security through NanoBioSensors: Adopt or adapt biomedical technologies?

Plant-based foods are integral part of our day-to-day diet. Increasing world population has put forth an ever increasing demand for plant-based foods, and food security remains a major concern. Similarly, biological, chemical, and physical threats to our food and increasing regulatory demands to control the presence of foreign species in food products have made food safety a growing issue. Nanotechnology has already established its roots in diverse disciplines. However, the food industry is yet to harness the full potential of the unique capabilities offered by this next-generation technology. While there might be safety concerns in regards to integration of nanoproducts with our food products, an aspect of nanotechnology that can make remarkable contribution to different elements of the food chain is the use of nanobiosensors and diagnostic platforms for monitoring food traceability, quality, safety, and nutritional value. This brings us to an important question that whether existing diagnostic platforms that have already been well developed for biomedical and clinical application are suitable for food industry or whether the demands of the food industry are altogether different that may not allow adoption/adaptation of the existing technology. This review is an effort to raise this important "uncomfortable" yet "timely" question.

Status of leptin in MBCR-ABL p210 positive chronic myeloid leukemia patients before and after imatinib therapy: a conflicting scenario.

BACKGROUND: Chronic myelogenous leukemia (CML), a myeoloproliferative disorder, is characterized by the presence of the fusion gene BCR-ABL in hematopoietic cells. Leptin, considered a link between cancer and obesity, has been reported to be actively involved in hemopoiesis and pathophysiology of CML. There are few and conflicting reports about the status of serum leptin levels and recently alteration in leptin has been reported due to imatinib mesylate. METHODS: Leptin and CRP were estimated in 30 (male: 20; female: 10) newly diagnosed and confirmed MBCR- ABL p210 positive CML patients before and after 3 months of therapy by commercial enzyme linked immunosorbent assays. Leptin levels were compared with 30 (male: 20; female: 10) age matched healthy controls accounting for the differences due BMI and gender. RESULTS: Leptin/BMI ratio was significantly raised in both male and female chronic phase patients as compared to controls (p < 0.001, p = 0.048) and accelerated phase patients as compared to controls (males, p < 0.001; females, p < 0.001). The normal gender difference and dependence on BMI was lost in patients. In patients, who failed to achieve hematological baseline, leptin/BMI was higher only in male patients (p = 0.012). Leptin/BMI also correlat- ed with TLC and blast percentage (TLC, R2 = 0.412, p = 0.001; Blast %, R2 = 0.408, p < 0.001). There was no correlation between leptin and CRP levels. Levels decreased significantly after complete hematological remission in both males and females (p = 0.001, p = 0.028). Levels after 3 months of imatinib therapy were significantly higher than controls in all patients not in remission (males, p < 0.001; females, p = 0.018) but only in male patients in re- mission (p = 0.002). CONCLUSIONS: Leptin levels were increased in CML patients. The findings suggest a possible role of leptin in patho- genesis of CML or disease progression independent of inflammatory state or reactionary rise. Imatinib itself may increase leptin levels, and, as leptin plays an active role in the pathophysiology of CML, this conflicting scenario needs further investigation. Alterations in leptin need to be investigated cautiously accounting for confounding and differences due to BMI and gender.

Robust suppression of HIV replication by intracellularly expressed reverse transcriptase aptamers is independent of ribozyme processing.

RNA aptamers that bind human immunodeficiency virus 1 (HIV-1) reverse transcriptase (RT) also inhibit viral replication, making them attractive as therapeutic candidates and potential tools for dissecting viral pathogenesis. However, it is not well understood how aptamer-expression context and cellular RNA pathways govern aptamer accumulation and net antiviral bioactivity. Using a previously-described expression cassette in which aptamers were flanked by two "minimal core" hammerhead ribozymes, we observed only weak suppression of pseudotyped HIV. To evaluate the importance of the minimal ribozymes, we replaced them with extended, tertiary-stabilized hammerhead ribozymes with enhanced self-cleavage activity, in addition to noncleaving ribozymes with active site mutations. Both the active and inactive versions of the extended hammerhead ribozymes increased inhibition of pseudotyped virus, indicating that processing is not necessary for bioactivity. Clonal stable cell lines expressing aptamers from these modified constructs strongly suppressed infectious virus, and were more effective than minimal ribozymes at high viral multiplicity of infection (MOI). Tertiary stabilization greatly increased aptamer accumulation in viral and subcellular compartments, again regardless of self-cleavage capability. We therefore propose that the increased accumulation is responsible for increased suppression, that the bioactive form of the aptamer is one of the uncleaved or partially cleaved transcripts, and that tertiary stabilization increases transcript stability by reducing exonuclease degradation.

Type 2 diabetes mellitus without vascular complications and ischemia modified albumin.

Ischemia modified albumin (IMA) is a proven cardiac marker but its role in type 2 diabetes mellitus without vascular complications has not been reported yet. Therefore, IMA was estimated in 60 newly diagnosed patients of type 2 diabetes mellitus and 30 healthy controls along with HbA1c and other investigations (to rule out vascular complications). There was no significant change in IMA levels in type 2 diabetic patients as compared to controls. No correlation could be found between IMA levels and HbA1c. We conclude that IMA levels are not affected in type 2 diabetes mellitus before the onset of vascular complications.

Vitreous loss during phacoemulsification in glaucoma patients: long-term intraocular pressure control.

PURPOSE: To assess the long-term effect of vitreous loss during phacoemulsification on intraocular pressure (IOP) control in glaucoma patients. SETTING: Birmingham and Midland Eye Centre, City Hospital, Birmingham, United Kingdom. METHODS: In this study, 26 glaucoma cases with vitreous loss during phacoemulsification were identified from operative room records. The cases were performed from January 1999 to December 2001. Minimum follow-up was 12 months. Postoperative IOP control in eyes with vitreous loss (Group 1) was assessed and compared with that in stable fellow eyes (Group 2), which served as controls. Another control group (Group 3) comprised patients with primary open-angle glaucoma who had successful phacoemulsification. Case notes of 22 patients from the same period fulfilled these criteria. RESULTS: The 3 groups were comparable in age, sex, laterality, ethnicity, mean IOP, and mean number of medications preoperatively. Twelve months after surgery, 43.2% in Group 1, 23.1% in Group 2 (P<.05) and 4.5% in Group 3 had significantly worse IOP; the differences between Group 1 and Groups 2 and 3 were statistically significant (P<.05). Intraocular pressure control was significantly better in Group 3 than in Group 2 (P<.05). CONCLUSIONS: Vitreous loss during cataract surgery in glaucoma patients adversely affected IOP control in the long term. Results suggest that uneventful cataract surgery in glaucoma patients improves IOP control.