Anticarcinogenic activity of blue fluorescent hexagonal boron nitride quantum dots: as an effective enhancer for DNA cleavage activity of anticancer drug doxorubicin.

Blue fluorescent hexagonal boron nitride quantum dots (h-BNQDs) of ∼10 nm size as an effective enhancer for DNA cleavage activity of anticancer drug doxorubicin (DOX) were synthesized using simple one-step hydrothermal disintegration of exfoliated hexagonal boron nitride at very low temperature âˆ¼ 120 °C. Boron nitride quantum dots (BNQDs) at a concentration of 25 µg/ml enhanced DNA cleavage activity of DOX up to 70% as checked by converting supercoiled fragment into nicked circular PBR322 DNA. The interaction of BNQDs with DOX is proportional to the concentration of BNQDs, with binding constant K b ∼0.07338 µg/ml. In addition, ab initio theoretical results indicate that DOX is absorbed on BNQDs at the N-terminated edge with binding energy -1.075 eV and prevented the normal replication mechanisms in DNA. BNQDs have been shown to kill the breast cancer cell MCF-7 extensively as compared with the normal human keratinocyte cell HaCaT. The cytotoxicity of BNQDs may be correlated with reduced reactive oxygen species level and increased apoptosis in MCF-7 cells, which may be liable to enhance the anticancerous activity of DOX. The results provide a base to develop BNQD-DOX as a more effective anticancer drug.

Urease immobilized fluorescent gold nanoparticles for urea sensing.

We report a surfactant-free synthesis of monodispersed gold nanoparticles (AuNPs) with average size of 15 nm. An approach for visual and fluorescent sensing of urea in aqueous solution based on shift in surface plasmon band (SPB) maxima as well as quench in fluorescence intensity. To enable the urea detection, we functionalized the thiol-capped gold nanoparticles with urease, the enzyme specific to urea using carbodiimide chemistry. The visible color changed of the gold colloidal solution from red to blue (or purple); this was evident from quenching in absorbance and fluorescence intensity, is the principle applied here for the sensing of urea. The solution turns blue when the urea concentration exceeds 8 mg/dL which reveals visual lower detection limit. The lower detection limits governed by the fluorescence quenching were found 5 mg/dL (R(2) = 0.99) which is highly sensitive and selective compared to shift in SPB maxima. The approach depicted here seems to be important in clinical diagnosis.

Value of histopathology, culture and guinea pig inoculation in osteoarticular tuberculosis.

Evaluation of histopathology, culture and guinea pig inoculation in 58 patients provisionally diagnosed as having osteoarticular tuberculosis in the Department of Orthopedics, P.B.M. Hospital, Bikaner is presented. The following conclusions were reached. Where facilities exist, all the investigations should be carried out in each case to obviate chances of missing the diagnosis and if possible all the pathological material available should be used. Otherwise histopathology plus guinea pig inoculation or histopathology plus culture should be mandatory. Clinical examination, radiological evidence and gross appearances of the lesion can only serve as an aid to preliminary diagnosis and/or prognosis.

Unusual manifestations of mycetoma.

Five cases of mycetoma of bone involving patella, shaft of tibia, medial malleolus, calcaneum and phalanx of great toe are presented. In all the cases bones were extensively damaged with minimal or no involvement of soft tissue, a very unusual feature. Aetiopathogenesis involvement of bone substantiated by facts, is discussed.