J

J. V. Prabhakar

Regional Cancer Center, Thiruvananthapuram

Publishes on Edible Oils Quality and Analysis, Food Chemistry and Fat Analysis, Health, Medicine and Society. 75 papers and 1.3k citations.

75Publications
1.3kTotal Citations

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Clinical Breast Examination: Preliminary Results from a Cluster Randomized Controlled Trial in India
Rengaswamy Sankaranarayanan, K. Ramadas, S. Thara et al.|JNCI Journal of the National Cancer Institute|2011
Cited by 243Open Access

A cluster randomized controlled trial was initiated in the Trivandrum district (Kerala, India) on January 1, 2006, to evaluate whether three rounds of triennial clinical breast examination (CBE) can reduce the incidence rate of advanced disease incidence and breast cancer mortality. A total of 275 clusters that included 115,652 healthy women, aged 30-69 years, were randomly allocated to intervention (CBE; 133 clusters; 55,844 women) or control (no screening; 142 clusters; 59,808 women) groups. Performance characteristics (sensitivity, specificity, false-positive rate, and positive predictive value) of CBE were evaluated. An intention-to-treat analysis was performed for comparison of incidence rates between the intervention and control groups. Preliminary results for incidence are based on follow-up until May 31, 2009, when the first round of screening was completed. Of the 50,366 women who underwent CBE, 30 breast cancers were detected among 2880 women with suspicious findings in CBE screening that warranted further investigations. Sensitivity, specificity, false-positive rate, and positive predictive value of CBE were 51.7% (95% confidence interval [CI] = 38.2% to 65.0%), 94.3% (95% CI = 94.1% to 94.5%), 5.7% (95% CI = 5.5% to 5.9%), and 1.0% (95% CI = 0.7% to 1.5%), respectively. The age-standardized incidence rates for early-stage (stage IIA or lower) breast cancer were 18.8 and 8.1 per 100,000 women and for advanced-stage (stage IIB or higher) breast cancer were 19.6 and 21.7 per 100,000 women, in the intervention and control groups, respectively.

Drug-induced Senescence Generates Chemoresistant Stemlike Cells with Low Reactive Oxygen Species
Santhi Achuthan, T.R. Santhoshkumar, J. V. Prabhakar et al.|Journal of Biological Chemistry|2011
Cited by 205Open Access

Tumor recurrence after chemotherapy or radiation remains a major obstacle to successful cancer treatment. A subset of cancer cells, termed cancer stem cells, can elude conventional treatments and eventually regenerate a tumor that is more aggressive. Despite the large number of studies, molecular events that govern the emergence of aggressive therapy-resistant cells with stem cell properties after chemotherapy are poorly defined. The present study provides evidence for the rare escape of tumor cells from drug-induced cell death, after an intermediate stay in a non-cycling senescent stage followed by unstable multiplication characterized by spontaneous cell death. However, some cells appear to escape and generate stable colonies with an aggressive tumor stem cell-like phenotype. These cells displayed higher CD133 and Oct-4 expression. Notably, the drug-selected cells that contained low levels of reactive oxygen species (ROS) also showed an increase in antioxidant enzymes. Consistent with this in vitro experimental data, we observed lower levels of ROS in breast tumors obtained after neoadjuvant chemotherapy compared with samples that did not receive preoperative chemotherapy. These latter tissues also expressed enhanced levels of ROS defenses with enhanced expression of superoxide dismutase. Higher levels of Oct-4 and CD133 were also observed in tumors obtained after neoadjuvant chemotherapy. Further studies provided evidence for the stabilization of Nrf2 due to reduced 26 S proteasome activity and increased p21 association as the driving signaling event that contributes to the transition from a high ROS quiescent state to a low ROS proliferating stage in drug-induced tumor stem cell enrichment.

A simple chemical method for stabilization of rice bran
J. V. Prabhakar, K. V. L. Venkatesh|Journal of the American Oil Chemists Society|1986
Cited by 93

Abstract A new simple chemical method for stabilization of rice bran is described. The process, based on the principle that lipase activity will be low at low pH, uses hydrochloric acid at 40 l/ton of bran for lowering the pH of rice bran from 6.9–6.0 to 4.0. The acid can be applied easily by sprinkling or spraying. The operation on small lots can be done by hand mixing of bran, but it is more efficient and effective if mechanical mixing, like a rotary or a trough mixer, is used. This simple method, which takes less than 4 min for a batch of 15 kg, will be useful for stabilization of rice bran in rice mills or where steam or electricity is unavailable. The process is being evaluated in commercial trials.

Oryzanol content of Indian rice bran oil and its extraction from soap stock.
Seetharamaiah, G. S., J. V. Prabhakar|CFTRI Institutional Repository|1986
Cited by 61

Oryzanol content of commercial rice bran oil was 1.34-1.95%, hexane extracted oil 1.12-1.38%, and chloroform:methanol (2:1) extracted oil 2.55-2.61%. The soap stock obtained by alkali refining of the oil contained 1.3-3.1% oryzanol. Optimum pH (levels tested 8.0-10.5) for extraction from soap stock was approx. 9.5. Diethyl ether was a better solvent than acetone. The oryzanol concn. could be upgraded by alumina column chromatography and recrystallization using methanol and methanol-acetone (2:1). The recrystallized material had an m.p. of 133-139 degree C and absorption maxima at 314, 290 and 230 nm in petroleum ether.

Lipid composition of rice (<i>Oryza sativa</i> L.) bran
J. Hemavathy, J. V. Prabhakar|Journal of the American Oil Chemists Society|1987
Cited by 60

Abstract The composition of lipids of bran from three varieties of rice is reported. Lipids extracted amounted to 21.9–23.0% of the bran dry weight and consisted of 88.1–89.2% neutral lipids, 6.3–7.0% glycolipids and 4.5–4.9% phospholipids. Neutral lipids consisted mostly of triacylglycerols (83.0–85.5%), monoacylglycerols (5.9–6.8%) and small amounts of diacylglycerols, sterols and free fatty acids. Three glycolipids and eight phospholipids were separated and characterized. Acylated steryl glucoside and digalactosyldiacylglycerol were the main glycolipids, while monogalactosylmonoacylglycerol was present in small amounts. The major phospholipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidic acid. Phosphatidylglycerol, lysophosphatidylcholine, lysophosphatidylethanolamine and acyl‐phosphatidylethanolamine were present in small quantities.