Biomedical subjects

M C Samson

Publications and source records attributed to M C Samson.

4 recordsLinked to original sources

PubMed2005

Development of a peptide nucleic acid polymerase chain reaction clamping assay for semiquantitative evaluation of genetically modified organism content in food.

In the present study a peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping method was developed and applied to the detection of genetically modified organisms (GMO), to test PCR products for band identity and to obtain a semiquantitative evaluation of GMO content. The minimal concentration of PNA necessary to block the PCR was determined by comparing PCRs containing a constant amount of DNA in the presence of increasing concentration of target-specific PNA. The lowest PNA concentration at which specific inhibition took place, by the inhibition of primer extension and/or steric hindrance, was the most efficient condition. Optimization of PCR clamping by PNA was observed by testing five different PNAs with a minimum of 13 bp to a maximum of 15 bp, designed on the target sequence of Roundup Ready soybean. The results obtained on the DNA extracted from Roundup Ready soybean standard flour were verified also on DNA extracted from standard flours of maize GA21, Bt176, Bt11, and MON810. A correlation between the PNA concentration necessary for inducing PCR clamping and the percentage of the GMO target sequence in the sample was found.

DNA Primers↗

PubMed2005

Multiplex polymerase chain reaction and ligation detection reaction/universal array technology for the traceability of genetically modified organisms in foods.

A multiplex polymerase chain reaction (PCR) system was developed for the simultaneous detection of target sequences in genetically modified soybean (Roundup Ready) and maize (MON810, Bt176, Bt11, and GA21). Primer pairs were designed to amplify the junction regions of the transgenic constructs analyzed and the endogenous genes of soybean (lectin) and maize (zein) were included as internal control targets to assess the efficiency of all reactions. This multiplex PCR has constituted the basis for an efficient platform for genetically modified organism traceability based on microarray technology. In particular, the ligation detection reaction combined to a universal array approach, using the multiplex PCR as target, was applied. High specificity and sensitivity were obtained.

DNA, Plant↗

PubMed1998

Dorsalis pedis flap donor site: acceptable or not?

The dorsalis pedis flap has been used successfully for 20 years, both as a pedicled transfer for local foot reconstruction and as a free microvascular transfer. Proponents cite the reliable vascularity, versatility, ease of harvest, and thinness. Although significant donor-site morbidity has been recognized previously, published reports have inadequately documented the long-term effects of dorsalis pedis flap harvest. The purpose of the present study was to obtain long-term follow-up data regarding the donor site on a total of 10 male patients who underwent dorsalis pedis flap harvest during the period from 1982 to 1984. Standardized questionnaires and chart reviews were completed, and physical examinations and photographs of each patient were carried out when possible. Eight patients were reviewed, and seven of them were examined and photographed (mean follow-up 13 years). All patients had initially experienced delayed donor-site healing (mean 18 months; range 3 to 36 months). In addition, soft-tissue infections (five of eight cases), osteomyelitis (one of eight cases), wound breakdown (seven of eight cases), scarring and contracture (four of seven cases), pain or other uncomfortable sensations in the foot (six of seven cases), and requirement for reoperation (three of eight cases) were significant complications of the procedure. Most patients were able to attain their preoperative level of physical activity (five of eight cases). Although generally favorable reconstructive results were obtained in this series, the long-term follow-up of donor-site healing indicates that this flap should be used with caution. In particular, delayed donor-site healing, need for wound revision, and long-term and possibly permanent donor-site symptoms are common.

Adult↗

PubMed1997

A comparative, randomized trial of UFT and 5-fluorouracil in combination with cyclophosphamide and doxorubicin in the treatment of advanced breast cancer patients at The Philippines General Hospital.

A comparative, randomized trial was conducted to determine the efficacy of oral UFT (Tegafur and Uracil) versus 5-fluorouracil (5-FU) in combination with cyclophosphamide and doxorubicin in patients with metastatic breast cancer. Of 62 evaluable patients, 31 received UFT (350 mg/m2/day orally x 14 days), doxorubicin (50 mg/m2 intravenously [I.V.] day 1) and cyclophosphamide (500 mg/m2 I.V. day 1). The other 31 patients received 5-FU (500 mg/m2 I.V. days 1 and 8), doxorubicin (50 mg/m2 I.V. day 1), and cyclophosphamide (500 mg/m2 I.V. day 1). Regimens were repeated for a total of six cycles. The two groups were comparable in terms of age, gender, performance status, menopausal status, and number and sites of metastases. No statistical difference in overall response rates was seen (UFT arm, 48.4% vs. 5-FU arm, 35 %; p = 0.30). Median response duration was 16 weeks (range, 4-30) for both arms. The toxicity profile (alopecia, anemia, leukopenia, thrombocytopenia, diarrhea) was similar in both groups and both regimens were well tolerated. Anemia and stomatitis were significantly more common in the 5-FU arm (p = 0.02). Thus, oral UFT has response rates and duration of response that are comparable to 5-FU in a combination regimen for advanced breast cancer.

Administration, Oral↗