Biomedical subjects

P Somasundar

Publications and source records attributed to P Somasundar.

3 recordsLinked to original sources

PubMed2002

Vitamin E and the Y4 agonist BA-129 decrease prostate cancer growth and production of vascular endothelial growth factor.

BACKGROUND: A biologically active form of vitamin E, alpha-tocopherol succinate (ATS), has been shown to induce apoptosis of hormone-refractory prostate cancer in vitro and inhibit cell growth in vivo. The gastrointestinal hormone peptide YY (PYY) has growth inhibitory activity against multiple cancer cell lines and is synergistic with ATS against breast and pancreatic cancer growth. BA-129, a specific Y4 receptor agonist, has growth inhibitory effects on pancreatic cancer in vitro. We investigated the effects of BA-129 and ATS on prostate cancer growth and evaluated their effects on vascular endothelial growth factor (VEGF) production. METHODS: A hormone-refractory human prostate cancer cell line, PC-3, was treated with ATS alone at 10 pg/ml, PYY or BA-129 alone at doses of 75 and 500 pmol/ml, or a combination of the two agents. Cell growth was measured by MTT assay and hemocytometry using trypan blue. Quantitative measurement of VEGF was performed by ELISA. Statistical analysis was achieved by ANOVA. RESULTS: ATS exhibited significant (P < 0.05) growth inhibitory effects in prostate cancer cells. PYY also inhibited growth (P < 0.05). ATS treatment reduced VEGF production (P < 0.05). PYY treatment increased VEGF. When ATS was given in combination with BA-129, VEGF production was further reduced (P < 0.05). CONCLUSIONS: Both PYY and ATS inhibit growth in hormone-refractory prostate cancer, with augmentation when used in combination. VEGF production is inhibited by vitamin E, but increased by PYY. ATS abolishes the augmented VEGF response to PYY. Our data suggest that PYY is involved in the regulation of VEGF production and prostate cancer growth.

Antineoplastic Agents↗

PubMed2000

Paragangliomas-- a decade of clinical experience.

BACKGROUND AND OBJECTIVES: This study is a review of 14 patients with paragangliomas between 1986 and 1996. The purpose was to determine the sites of origin, clinical manifestations and analyze the benefits of different treatment modalities. METHODS: There were 20 tumors in 14 patients. Three (21.0%) of the patients had familial history. There were 7 (50%) females and 7 (50%) males. Anatomically 14 (70%) tumors were in head and neck, 5 (25%) were in the retroperitoneum, one (5%) was in the heart. Of the head and neck tumors 9 (64.25%) were in the carotid body, 3 (21.42%) were found in the vagus, and 2(14.33%) were found in the middle ear. The tumor found in the heart was in the atrial septum. The clinical behavior of paragangliomas is determined by cellular characteristics, secreting capabilities and tumor location. The symptoms and signs depend on the site of origin and the stage at which it presents. The clinically functioning tumors were 3 (17%) in our experience and they typically present with uncontrolled hypertension. The carotid body and mediastinal tumors usually manifested as asymptomatic masses. The intravagal tumors presented with paresis of the nerve. Malignancy rarely occurs and is defined by the existence of metastasis rather than by histology. In our series 2 (10%) of the patients presented with metastasis to lymph nodes, and the vertebrae. The diagnoses in our patients were established by CT and MRI scanning. Angiography was performed in 5 patients with carotid body tumor, two of whom underwent therapeutic embolization to reduce the tumor size. The mainstay of treatment was surgical removal, though radiation has been advocated for patients who cannot undergo surgery. RESULTS: All patients underwent successful surgical resection of the tumor after appropriate preoperative preparation. Late mortality occurred in two (12.5%) patients at 3 and 5 years from unrelated etiology. Four (25%) patients were lost to follow-up. Three (18.7%) patients developed new primaries, two of them at two years and one after 8 years. One (6%) patient developed recurrent paraganglioma after remaining disease free for 20 years. CONCLUSION: In conclusion, paragangliomas are rare with multicentricity being more common in patients with familial history. The malignant potential of the tumor is determined by metastasis as there are no characteristic cellular change. Aggressive surgery is mandatory to obtain disease free survival with low morbidity and mortality. Recurrences can also be successfully operated with low morbidity.

Adolescent↗

PubMedDate not supplied

Persantine improves acute pancreatitis in vitro.

Persantine combined with TNF-a enhances antiproliferative activity in human tumor cells. We hypothesized that the vasodilator persantine would ameliorate acute pancreatitis (AP) in vitro. Rat pancreatic ductal cells were cultured using standard techniques. Acute pancreatitis was induced by adding cerulein (10(-9) M) or TNF-a (200 ng/ml). AP was verified by increased amylase production. Persantine was added at concentrations from 0.1 uM to 100 uM post cerulein or TNF-a treatment. Statistical analysis was achieved by ANOVA. Amylase production was significantly increased (p < 0.05) compared with control upon stimulation with either cerulein or TNF-a. When persantine was added in graded concentrations from 0.1 uM to 100 uM to cerulein treated cells, it decreased amylase production significantly (p < 0.05) at 100 uM. However, when persantine was added to TNF-a treated cells, it decreased amylase production (p < 0.05) at the lower concentrations of 0.1 uM and 1 uM. We have shown for the first time that AP, resulting from either mild (cerulein) or severe (TNF-a) stimulation, is significantly improved by treatment with persantine.

Acute Disease↗