Biomedical subjects

A W Philipp

Publications and source records attributed to A W Philipp.

4 recordsLinked to original sources

PubMed2003

Epigallocatechin gallate can significantly decrease free oxygen radicals in the reperfusion injury in vivo.

OBJECTIVE: There is experimental evidence that oxygen-derived free radicals (Superoxide (O(2)(-))) play a key role in tissue damage in ischemia-reperfusion injury. Among various antioxidants tested in vitro, natural polyphenols like Epigallocatechine gallate (EGCG) show a 164-fold higher scavenging activity for O(2)(-) than ascorbic acid We therefore conducted an animal study in order to investigate the impact of EGCG on O(2)(-) production during reperfusion after defined periods of ischemia in the muscle tissue of the rat, using a recently developed cytochrome c-based biosensor for on-line in vivo monitoring of O(2)(-). MATERIALS AND METHODS: Femoral artery and vein were dissected below the inguinal ligament in male Wistar rats. The cytochrome c-based biosensor was placed in the gastrocnemius muscle. Ischemia was induced by clamping the femoral vessels. Ischemia times were either 60 (n = 14) or 120 (n = 14) minutes. Six animals in each group received 4 mg/kg body weight EGCG intravenously at the time of reperfusion, another six animals in each group served as controls (no treatment). Additionally, two animals in each group received the same volume of saline instead of EGCG. The current response of the biosensor corresponding to the O(2)(-) concentrations in vivo was recorded on a PC. The gastrocnemius muscles were harvested for histological evaluation. RESULTS: The average maximum O(2)(-) concentration after 60 minutes of ischemia was 188, 18 nmol/L (23 pA) compared to 90 nmol/L (11 pA) (P <.01) with EGCG application. The mean O(2)(-) value after 120 minutes was 220 nmol/L (27 pA) versus 135 nmol/L (16.5 pA) (P <.01) with EGCG, respectively. Histological analysis showed advanced muscle cell injury and neutrophil infiltration in the group without EGCG. No O(2)(-) reduction could be verified administering saline instead of EGCG. CONCLUSION: For the first time the scavenging activity of an antioxidant was verified in vivo on-line. EGCG significantly diminished O(2)(-) tissue concentrations after 60 or 120 minutes of ischemia by an average of nearly 50%, suggesting its therapeutic potential.

Animals↗

PubMed2003

In a pig model ePTFE grafts will sustain for 6 weeks a confluent endothelial cell layer formed in vitro under shear stress conditions.

OBJECTIVE: to investigate in a pig model whether small diameter ePTFE grafts will sustain a confluent endothelial cell layer formed in vitro under shear stress conditions. MATERIALS AND METHODS: thirteen ePTFE (4 mm) grafts were implanted end to end in the right femoral artery of; 8 grafts had been endothelialized in vitro. Grafts were left in situ for 6 weeks then evaluated with ultrasound and histology. RESULTS: seven endothelialized graft were patent with confluent endothelial cell lining. None of the control grafts were patent or showed evidence of an endothelial lining. CONCLUSION: in this pig model ePTFE grafts sustained for 6 weeks a confluent endothelial cell layer formed in vitro under shear stress.

Animals↗

PubMed2002

[Leflunomide reduces the angiogenesis score and tumor growth of subcutaneously implanted colon carcinoma cells in the mouse model].

BACKGROUND: The inhibition of tumorangiogenesis may be of importance in the additive treatment of various cancers. Leflunomide, a drug which has been approved in Germany for the therapy of rheumatoid arthritis, inhibits the activity of several growth factors in vitro. The aim of this study was to investigate the effects of the drug on tumor angiogenesis in a nude mouse model. MATERIALS AND METHODS: A total of 40 nude mice were injected with human colon carcinoma cells. Following randomization in 4 groups, therapy started on day five. Group 1 was treated daily with orally administered Leflunomide (35 mg/kg) dissolved in 1.5% Carboxymethylcellulose (CMC). Group 2 served as a control group and received 1 ml CMC orally per day. The animals of group 3 were treated daily with 35 mg Leflunomide/kg KG and 500 mg Uridine/kg dissolved in 1 ml Nacl 0.9% intraperitoneally. The 4th group again served as a control group and received only 500 mg Uridine/kg intraperitoneally each day. The main outcome criterion was the angiogenesis score (AS). In addition, the tumor volume and tumor weight were also assessed. The AS was determined by immunohistochemistry using an antibody against factor VIII related antigen. RESULTS: All animals tolerated the procedure well. In the Leflunomide and the Leflunomide/Uridine group the angiogenesis score (p < 0.01), the tumor volume (p < 0.01) and the tumor weight (p < 0.01) were lower compared to the respective control groups. CONCLUSION: The administration of Leflunomide leads to a significant reduction of tumor weight and tumor volume following subcutaneous injection of human colon carcinoma cells in a nude mouse model. This could be due to the reduction of tumor angiogenesis. Following further experimental and clinical studies, Leflunomide may come to play a role in the additive treatment of colonic carcinoma.

Administration, Oral↗

PubMed2002

Long-term survival of a patient with small-cell lung cancer (SCLC) following treatment with thalidomide and combination chemotherapy.

Thalidomide, an angiogenesis inhibitor is currently used in clinical trials in the US and Europe in combination with chemotherapy for the treatment of various solid tumors. The prognosis of patients suffering from small-cell lung cancer (SCLC) is poor. A 73-year-old female with extensive disease of SCLC was given six courses of chemotherapy with adriamycine, cyclophasphamide and oncovine, which led to complete remission of the disease. Following written informed consent, the patient has been treated with thalidomide 200 mg orally on a daily basis for 2 years and 5 months. There has been no sign of tumor recurrence during the follow-up. This case underlines the possible role of additional treatment with angiogenesis inhibitors in combination with traditional chemotherapy in the therapy of SCLC. Although there is no proof that thalidomide contributed to this good outcome and no conclusions can be drawn from this treatment in a single patient, further studies may determine the role of thalidomide as an adjuvant antiangiogenic agent in the therapy of SCLC.

Aged↗