Spatial and temporal variability in concentration and characteristics of aerosols at Visakhapatnam (east) and Goa (west) coasts of India

Knowledge on the variability in quantity and compositions of various size groups of aerosols is important to understand their sources and their role in biogeochemical and climate processes. Here, we studied total suspended particles (TSP), PM₁₀ and PM_2.5 for their quantitative and water soluble compositional (F^-, Cl^-, SO₄^2-, NO₃^-, NH₄⁺, Na⁺, K⁺, Ca²⁺, and Mg²⁺) distributions, and to understand their nature and potential sources at Goa and Visakhapatnam on the west and east coasts, respectively, of India. While the mean concentrations of TSP were found to be 117 ± 44 and 85 ± 51 μg/m³ its maximal levels occurred in spring intermonsoon (SIM; 141 ± 52) and winter monsoon (WM; 155 ± 145 μg/m³) seasons at Goa and Visakhapatnam, respectively. PM₁₀ and PM_2.5 exhibited higher ranges at Visakhapatnam than Goa. The increase in PM_2.5 abundance from WM to SIM at Visakhapatnam seems to occur in coincidence with decrease in TSP favored by topography and ambient meteorological conditions. Locally released and seasonally transported (from land and sea) constituents contributed to the observed variability in aerosol compositions. Sulphate dominated the aerosol composition at both Goa (57-64%) and Visakhapatnam (43-55%) followed by NO₃^- (5-16% and 6-18%, respectively) where the former component was higher in PM₁₀ and PM_2.5. The NO₃^- was more in TSP. Relations between SO₄^2- and NH₄⁺ suggested possible presence of NH₄HSO₄. Examination of ionic ratios and balance suggested near neutrality in PM₁₀ and PM_2.5 while TSP was acidic at the both locations. Notable relations between Ca²⁺ and NO₃^-, particularly in PM₁₀ at Goa, indicated their release from mining related activities.

Custom Mega Prosthesis in Metachronous Osteosarcoma

Background: The objective of the current study was to determine the incidence, clinical and pathologic characteristics, and outcome of patients with conventional osteosarcoma who developed metachronous tumours and treated by limb salvage surgery with Custom Mega Prosthesis.

Methods: Among 1198 osteosarcoma patients who were treated with limb salvage surgery and implantation of custom mega prosthesis, 6 patients were found to have metachronous lesions. The absence of pulmonary metastases was confirmed by chest radiographs and computed tomography while radionuclide bone scan and biopsy were used to confirm the absence of skeletal metastases. The patients were treated by limb salvage surgery with custom mega prosthesis for the metachronous tumour and functional outcome was evaluated by MSTS scores.

Results: Index primary tumours involved the femur (n=3) and the tibia (n=3) and were treated with limb salvage surgery using endoprosthetic reconstruction. Single metachronous tumours developed in the all of these patients with the interval between identification of the primary tumour to development of the metachronous tumours varying from 18 months to 41 months. All metachronous tumours were treated with neoadjuvant chemotherapy and limb salvage surgery. We obtained excellent functional outcome for primary tumours and good functional outcome for metachronous tumours. Two patients succumbed to disease due to pulmonary and cerebral metastasis during follow-up.

Conclusions: With advances in survival rate in the multidrug chemotherapy era in the post tumoursresection period, advanced diagnostic modalities help in diagnosing metachronous osteosarcoma. It should be recognized as important sequelae in long-term survivors. Meticulous follow-up is required to permit early detection and successful therapeutic intervention. Limb salvage surgery has provided consistent good results in metachronous osteosarcoma patients.

Gene therapy as a potential tool for treating neuroblastoma-a focused review

Neuroblastoma, a solid tumor caused by rapid division of undifferentiated neuroblasts, is the most common childhood malignancy affecting children aged <5 years. Several approaches and strategies developed and tested to cure neuroblastoma have met with limited success due to different reasons. Many oncogenes are deregulated during the onset and development of neuroblastoma and thus offer an opportunity to circumvent this disease if the expression of these genes is restored to normalcy. Gene therapy is a powerful tool with the potential to inhibit the deleterious effects of oncogenes by inserting corrected/normal genes into the genome. Both viral and non-viral vector-based gene therapies have been developed and adopted to deliver the target genes into neuroblastoma cells. These attempts have given hope to bringing in a new regime of treatment against neuroblastoma. A few gene-therapy-based treatment strategies have been tested in limited clinical trials yielding some positive results. This mini review is an attempt to provide an overview of the available options of gene therapy to treat neuroblastoma.

Sub-hourly changes in biogeochemical properties in surface waters of Zuari estuary, Goa

Processes in natural waters are highly variable in time and space. Although changes are expected in short-time scales, how short one could get to measure reliably is subjective to sampling strategies and methodologies. Here, we show that sub-hourly changes in surface waters dissolved oxygen, nutrients, and pigments are measurable and significant in an estuarine system. Tidal circulation has been found to strongly influence the observed changes and has implications to material fluxes in and out of estuaries.

Spatial variations of DMS, DMSP and phytoplankton in the Bay of Bengal during the summer monsoon 2001

Data on the distribution of dimethylsulphide (DMS) and dimethylsulphoniopropionate (DMSP) in relation to phytoplankton abundance in different oceanic environments is important to understand the biogeochemistry of DMS, which plays an important role in the radiation balance of the earth. During the summer monsoon of 2001 measurements were made for DMS and DMSPt (total DMSP) together with related biological parameters in the Bay of Bengal. Both DMS and DMSPt were restricted to the upper 40 m of the water column. Diatoms accounted for more than 95% of the phytoplankton and were the major contributors to the DMS and DMSPt pool. The mean concentration of DMS in the upper 40 m was observed to be around 1.8+/-1.9 nM in the study area, while DMSPt concentrations varied between 0.7 nM and 40.2 nM with a mean of 10.4+/-8.2 nM. The observed lower DMSPt in the northern Bay in spite of higher mean primary productivity, chlorophyll a and phytoplankton cell counts seemed to result from grazing. Though salinity divides the Bay into different biogeochemical provinces there is no relation between salinity and DMS or DMSPt. On the other hand DMS was linearly related to chlorophyll a:phaeopigments ratio. The results suggest the need for deeper insight into the role of diatoms in the biogeochemical cycling of DMS.