1D-2D hybrids as efficient optoelectronic materials: a study on graphitic carbon nitride nanosheets wrapped with zinc oxide rods.

Zinc oxide (ZnO) nanorods (NRs) wrapped with graphitic carbon nitride (GCN) nanosheet (NS) hybrids have been synthesized by a simple chemical process. The as-prepared samples are characterized by X-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy, Fourier transformed infrared spectroscopy, UV-Vis spectroscopy and photoluminescence spectroscopy. The images obtained from the transmission electron microscopic study and the existence of C-N stretching modes as observed from Fourier transform infrared spectroscopy confirm the successful attachment of GCN NSs onto the ZnO NRs. It is seen that hybrid samples show broad photoluminescence (PL) emission with enhanced defect related emission along with a quenching effect due to the charge transfer mechanism. The results have been explained by taking into consideration the three different types of electron transitions occurring within the type-II band structure of the hybrid samples. Moreover a study on the conductivity of the samples is carried out under dark conditions and also under ultraviolet (UV) light irradiation. It is observed that the hybrid samples show significantly improved conductivity under both dark and UV irradiated conditions. The absorbance of the samples in the UV range shows better conductivity under UV conditions as compared to dark conditions.

Selection of DNA aptamers for extra cellular domain of human epidermal growth factor receptor 2 to detect HER2 positive carcinomas

Background. Human epidermal growth factor receptor 2 (Her2, an orphan receptor of ErbB family) is considered as an important biomarker as it plays a key role in the development and progression of aggressive types of breast, ovarian, stomach and gastric cancer. In the present study, we developed novel DNA aptamers against the extra-cellular domain (ECD) of Her2 protein for detection of Her2-positive carcinomas. Methods. We cloned and expressed Her2-ECD protein in E. coli system. After purification, the protein was used as a bait for screening of specific DNA aptamer candidate from a pool of 1014-15 random oligonucleotides through in vitro Systematic Evaluation of Ligands by Exponential Enrichment (SELEX) process. The aptamer-protein binding kinetics was elucidated by isothermal calorimetry. The specificity of FAM-labelled ECD_Apt1 towards Her2-positive cell lines was estimated by FACS and immunofluorescence assay. The specificity of the candidate was also verified with the tissue samples of breast cancer patients by immunohistochemistry process. Results. Among four selected candidates, ECD_Apt1 (having minimum ∆G = -3.24) showed the highest binding affinity (Kd = 6.33 ± 0.86 nM) to Her2-ECD protein. The aptamer-protein sandwich assay showed a linear rise in chemiluminescence (at 490 nm wavelength) in the dynamic range of 100−700 nM ECD_Apt1 with a detection limit of 12.5 ± 2.5 ng/mL. Biotinylated ECD_Apt1 showed stronger cytoplasmic staining in Her2-positive breast cancer cell lines (SKBR3) compared to Her2-negative cells (MDA MB 231, MCF7). In paraffin-embedded breast cancer tissue sections, it showed specific and selective localization in the cytoplasmic niche of malignant duct cancer cells without any cross-reactivity to fibroblasts, inflammatory cells and adipocytes. Conclusions. Binding assays, cytochemical and histochemical studies support ECD_Apt1 as a potential theranostic agent for Her2-positive carcinomas. ECD_Apt1 could be an effective low-cost alternative to conventional anti-Her2 antibody in solid phase immunoassays for cancer diagnosis and related applications (AU)

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Selection of DNA aptamers for extra cellular domain of human epidermal growth factor receptor 2 to detect HER2 positive carcinomas.

BACKGROUND: Human epidermal growth factor receptor 2 (Her2, an orphan receptor of ErbB family) is considered as an important biomarker as it plays a key role in the development and progression of aggressive types of breast, ovarian, stomach and gastric cancer. In the present study, we developed novel DNA aptamers against the extra-cellular domain (ECD) of Her2 protein for detection of Her2-positive carcinomas. METHODS: We cloned and expressed Her2-ECD protein in E. coli system. After purification, the protein was used as a bait for screening of specific DNA aptamer candidate from a pool of 1014-15 random oligonucleotides through in vitro Systematic Evaluation of Ligands by Exponential Enrichment (SELEX) process. The aptamer-protein binding kinetics was elucidated by isothermal calorimetry. The specificity of FAM-labelled ECD_Apt1 towards Her2-positive cell lines was estimated by FACS and immunofluorescence assay. The specificity of the candidate was also verified with the tissue samples of breast cancer patients by immunohistochemistry process. RESULTS: Among four selected candidates, ECD_Apt1 (having minimum ∆G = -3.24) showed the highest binding affinity (K d = 6.33 ± 0.86 nM) to Her2-ECD protein. The aptamer-protein sandwich assay showed a linear rise in chemiluminescence (at 490 nm wavelength) in the dynamic range of 100-700 nM ECD_Apt1 with a detection limit of 12.5 ± 2.5 ng/mL. Biotinylated ECD_Apt1 showed stronger cytoplasmic staining in Her2-positive breast cancer cell lines (SKBR3) compared to Her2-negative cells (MDA MB 231, MCF7). In paraffin-embedded breast cancer tissue sections, it showed specific and selective localization in the cytoplasmic niche of malignant duct cancer cells without any cross-reactivity to fibroblasts, inflammatory cells and adipocytes. CONCLUSIONS: Binding assays, cytochemical and histochemical studies support ECD_Apt1 as a potential theranostic agent for Her2-positive carcinomas. ECD_Apt1 could be an effective low-cost alternative to conventional anti-Her2 antibody in solid phase immunoassays for cancer diagnosis and related applications.

Comparative efficacy of furazolidone and nalidixic acid in the empirical treatment of acute invasive diarrhea: randomized clinical trial.

Efficacy of furazolidone and nalidixic acid was compared in a randomized trial involving 72 children with acute invasive diarrhea. Thirty six children received furazolidone (7.5 mg/kg/day) and 36 children received nalidixic acid (55 mg/kg/day). Clinical characteristics of the two treatment groups were comparable on admission. Of these, 34 children in furazolidone treated group and 29 children in nalidixic acid treated group completed the full course of treatment and were analyzed finally for clinical efficacy. Clinical cure was observed in 29(85.3%) children treated with furazolidone and 29(100.0%) children treated with nalidixic acid. Nalidixic acid treated group had statistically significantly higher cure rate (p = 0.039) as compared to furazolidone treated group. However, 85% cure rate in furazolidone treated group may be potentially useful for the treatment of acute invasive diarrhea because of decreasing efficacy of nalidixic acid against shigellosis in many countries.

Answers to questions in relation to oral rehydration therapy.

PIP: Oral rehydration therapy (ORT) has simplified treatment of diarrheal dehydration. Hospitals in India have diarrheal treatment and training units (DTUs) to help manage the many diarrheal cases. DTU staff keep children for 4-6 hours to correct the dehydration with ORT and feeding. Health personnel undergo training in diarrhea management at DTUs. ORT is the preferred treatment in almost all cases of acute diarrhea. It is not best for diarrheal cases which exhibit shock, profuse vomiting (3 times/hour), glucose malabsorption, abdominal distension or paralytic ileus, and high rate of purging (15 ml/kg body weight/hour). ORT successfully treats 95% cases of infantile diarrhea, even Rotavirus-caused diarrhea. Health workers should begin treating cases of severe dehydration with intravenous (IV) therapy and then administer ORT 3-4 hours later for infants and 1-2 hours later for adults. If IV therapy is not possible, the patient should receive oral rehydration solution (ORS) nasogastrically and then referred to a facility with IV therapy. WHO's ORS formula is safe for newborns and young infants. ORT is appropriate even when diarrheal cases are vomiting. ORT tends to stop vomiting 1-2 hours after initial ORS administration because it corrects acidosis. The glucose in WHO's ORS facilitates absorption of adequate sodium across the intestinal mucous membrane. ORS also restores the loss potassium ions and HCO3/citrate. If ORS is not available, sugar salt solution can be used. To achieve the optimum concentration, the amount of sucrose has to be twice that of glucose. ORS should be stored in a cool place, be covered, and used for no more than 24 hours. Antiemetics should not be given during ORT. Most diarrheas do not require any antibiotic. Sterile water is not necessary to prepare ORS. Rice gruel, coconut water, and pulse water are home available fluids which can treat dehydration. Breast feeding and regular feeding should continue during diarrheal episodes.^ieng