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Biomedical subjects

G Gupta

Publications and source records attributed to G Gupta.

202 records · Page 12Linked to original sources
PubMedDate not supplied

Attenuation of methyl tert-butyl ether in water using sunlight and a photocatalyst.

The use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in increasing pollution of groundwater. Most of the conventional treatment technologies are inefficient or costly when the initial concentration of MTBE is low (< 200 microg/L). To find an ecology friendly and inexpensive method for MTBE remediation, we used solar radiation with titanium dioxide (TiO2) as a photocatalyst. For synthetic samples, almost complete degradation (99+%) of MTBE was observed at the end of 5-hour test run with 0.05 g/L of slurry TiO2. Intermediate products detected were tertiary butyl formate, tertiary butyl alcohol, and trace amounts of acetone. Studies conducted using contaminated groundwater samples with TiO2 and sunlight showed that aromatic organic species benzene, toluene, ethylbenzene, and xylenes (BTEX) were degraded up to a factor of 10 times faster than MTBE. However, dissolved metals (Fe2+) and chloride ions in contaminated waters decreased the photo-activity of TiO2 for the degradation of MTBE. Reducing the pH of the groundwater samples increased the MTBE degradation rate threefold. Photocatalysis accelerates the solar degradation of MTBE and reduces its half-life by more than 3 orders of magnitude. The study indicated that solar degradation is a low-cost and effective alternative to attenuate MTBE in drinking water supplies.

Carcinogens↗
PubMedDate not supplied

High-risk human papillomavirus, tumor suppressor protein p53 and mitomycin-C in invasive squamous cell carcinoma cervix.

BACKGROUND: Clinical data relating to human papillomavirus (HPV) infection and p53 status in cervical cancer has been sparse and confusing. AIM: To evaluate high-risk HPV and expression of tumor suppressor protein p53 in squamous cell carcinoma of cervix and to assess response to mitomycin-C in neo-adjuvant chemotherapy. SETTING AND DESIGN: Teaching College Hospital; Gynecologic Oncology Unit and Department of Pathology. Prospective, randomized. MATERIALS AND METHODS: Expression of p53 protein was assessed, using immunohistochemistry with mouse monoclonal antibody in 30 consecutive patients undergoing radical hysterectomy or admitted for neo-adjuvant chemotherapy. Human papillomavirus DNA (HPV DNA) was assessed using hybrid capture II technology. Patients eligible for chemotherapy were randomized into vincristine, bleomycin and cisplatin (VBP) group and VBP with mitomycin C group. STATISTICAL ANALYSIS: Chi-square test, one-way ANOVA, Pearson's correlation; Mann-Whitney, McNemar and Fischer's exact tests were used for statistical analysis. RESULTS: All patients with cancer cervix were positive for high-risk HPV DNA having relative light units/cut off values ranging from 3.4-2389.21 (P value = 0.006). High viral load of high risk HPV DNA was seen in advanced stages (P = 0.05) and an association of viral load with tumor volume was also seen (r = 0.361, P = 0.05). Analysis of p53 protein in cervical carcinoma patient showed expression in 50% of cancer specimens (P value < 0.001). McNemar's and Fischer's exact test showed no change in p53 status post-chemotherapy; however 66% of stage II B patients in VBP-M group became operable. CONCLUSION: High-risk HPV was universally present in all cases of cancer cervix and viral load was associated with stage and tumor volume while p53 protein was expressed in 50% of cases suggesting deregulation. More studies using mitomycin-C in cervical cancer treatment protocols are needed.

Adolescent↗