Biomedical subjects

Paul Walker

Publications and source records attributed to Paul Walker.

21 records · Page 2Linked to original sources

PubMed2003

Solids, organic load and nutrient concentration reductions in swine waste slurry using a polyacrylamide (PAM)-aided solids flocculation treatment.

Increased swine production results in concentration of wastes generated within a limited geographical area, which may lead to land application rates exceeding the local or regional assimilatory capacity. This may result in pollutant transfer through surface water or soil-groundwater systems, environmental degradation, and/or odor concerns. Existing swine waste pit storage and lagoon treatment technologies may be inadequate to store or treat waste prior to land application without these concerns resulting. Efficient swine waste solids separation may reduce environmental health concerns and generate a value-added bioresource (solids). This study evaluated the efficiency of a polyacrylamide (PAM) flocculant-aided solids separation treatment to reduce pollution indicator concentrations in raw (untreated) swine waste slurry. Swine waste slurry solids separation efficiency through gravity settling (sedimentation) was evaluated before and after the addition of a proprietary polymeric (PAM) flocculant. Results indicated that polymer amendments at concentrations of 62.5-750 mg/l improved slurry solids separation efficiency and significantly reduced concentrations of other associated aquatic pollution indicators in a majority of analyses conducted (33 of 50 total analyses conducted). Results also suggested that PAM-aided solids separation from swine waste slurry might facilitate further treatment and/or disposal and therefore reduce associated environmental degradation potential.

Acrylic Resins↗

PubMed2003

A phase II study of 13-cis retinoic acid plus interferon alpha-2a in advanced stage penile carcinoma: an Eastern Cooperative Oncology Group study (E3893).

PURPOSE: Combined biological therapy with 13-cis-retinoic acid (13-cRA) and interferon alpha-2a (IFN alpha-2a) was reported to be highly effective in squamous cell carcinoma of the cervix and skin. Squamous cell carcinoma of the penis is rare in the United States, accounting for less than 1/2% of all male malignancies. Because of the association of infection with human papillomavirus with both carcinomas of the cervix and penis and their shared squamous cell histology, we carried out a phase II study of 13-cRA and IFN alpha-2a in carcinoma of the penis. MATERIALS AND METHODS: Eighteen ambulatory patients with surgically unresectable, recurrent, and/or metastatic squamous cell carcinoma of the penis were treated with IFN alpha-2a, 3MU/day administered subcutaneously and 13-cRA, 1 mg/kg orally daily for at least eight weeks, unless intolerable toxicity occurred. RESULTS: One patient was ineligible; one patient withdrew prior to treatment. Among the 16 eligible, treated patients, there was one complete response. Fourteen patients had progressive disease as their only treatment effect. Two patients were unevaluable for tumor response because they had no follow-up tumor measurements. No unexpected treatment-related toxicities were found on study. The only common form of grade 3 toxicity was hypertriglyceridemia found in eight of the 17 patients (47%). No toxicities above grade 3 were observed. CONCLUSION: In contrast to its benefit in squamous cell carcinomas of the cervix and skin, the combination of 13-cRA and IFN alpha-2a has low efficacy in advanced carcinoma of the penis.

Adult↗

PubMed2002

Spectroscopic data following stroke reveal tissue abnormality beyond the region of T2-weighted hyperintensity.

Cerebral tissue with T2 magnetic resonance imaging (MRI) abnormalities following stroke is generally considered infarcted, while surrounding regions with normal MRI appearance are believed to be healthy. To assess whether these surrounding regions consist of normal tissue, we explored the distribution of N-acetylaspartate (NAA) and lactate within and around the hyperintense area on T2-weighted MRI using proton MR spectroscopy. The study was carried out in 25 patients with middle cerebral artery occlusion imaged between 1 and 42 days after stroke onset. NAA/choline (Cho) ratios were significantly reduced in both areas of T2 hyperintensity and in surrounding tissue. The reduction was greater in the region of T2 hyperintensity than in the surrounding region (-50% vs. -28%, respectively) and was unrelated to the delay after the ictus. Lactate/Cho ratios increased massively within the abnormal T2 area, but did not differ from control values beyond the margin of hyperintensity. Overall data indicate that T2 visible lesions on MRI do not infer the entire injured tissue.

Aspartic Acid↗