Biomedical subjects

Mark Wells

Publications and source records attributed to Mark Wells.

2 recordsLinked to original sources

PubMed2003

Does cerclage location influence perinatal outcome?

OBJECTIVE: The study was undertaken to measure cerclage location within the cervix and to determine whether placement closer to the internal os is related to perinatal outcome. STUDY DESIGN: We analyzed data collected during a randomized trial of cervical cerclage versus no cerclage that was conducted at Lehigh Valley Hospital between May 1998 and June 2001 in women with ultrasound findings of short cervix less than 25 mm or funneling between 16 and 24 weeks' gestation. Women who were randomly assigned to the cerclage arm had cervical measurements performed before cerclage, including dilation of the internal os, depth of membrane prolapse into the endocervical canal, cervical length below any funnel (distal length), and total cervical length (including any funnel). Measurements obtained after cerclage placement included the distance from external os to cerclage (A), and a repeat of the same four measurements. The distance from the external os to the cerclage (A) was divided by the total cervical length (B) and a cerclage to cervical length ratio (A/B) was calculated. The relationship between these measurements and gestational age at birth was assessed by linear regression analysis. RESULTS: Of 150 patients enrolled, 74 received a McDonald cerclage suture. Mean distal cervical length was 1.9+/-0.9 cm before and 2.9+/-1.0 cm after cerclage (P=.001). The mean distance between the cerclage and external os (A) was 1.8+/-0.6 cm; the total cervical length after cerclage (B) was 3.6+/-0.9 cm. The mean cerclage to cervical length ratio (A/B) was 0.5+/-0.1. Linear regression analysis did not demonstrate a correlation between either the cerclage to external os measurement (A) or the cervical length ratio (A/B) and gestational age at birth (R(2)=0.0006 and 0.008, P=.8 and.6, respectively). CONCLUSION: The length of the cervix below the level of cerclage is not related to duration of pregnancy in women treated with cerclage because of ultrasound evidence of cervical effacement.

Adult↗

PubMed2002

Rescue of hematopoietic stem cells following high-dose radiation injury using ex vivo culture on endothelial monolayers.

Military personnel are at significant risk for potentially lethal myeloablative injury secondary to nuclear accident, nuclear attack, or chemical weapons attack. In an attempt to develop culture conditions in which hematopoietic stem cells might be rescued from the effects of radiation, we irradiated (1,000 cGy split dose) 6-week-old C57BL/6 (Ly 5.1) and syngeneic C57BL/6 (Ly 5.2) mice and tested whether bone marrow mononuclear cells (MNCs) harvested postirradiation could be rescued via coculture in porcine microvascular endothelial cell (PMVEC) monolayers. We found that a subpopulation of bone marrow MNCs exposed to 1,000 cGy could be maintained and expanded over 10 days in a PMVEC culture (3.8-fold expansion), whereas liquid suspension culture did not maintain a significant number of hematopoietic cells postirradiation. Colony-forming assays demonstrated that murine MNCs exposed to 1,000 cGy did not give rise to granulocyte/macrophage colony-forming units (CFU-GM), erythroid burst-forming units (BFU-e), or CFU-Mix in 14-day cultures, whereas irradiated MNCs that were subsequently cultured in PMVEC-generated CFU-GM, BFU-e, and CFU-Mix at cloning efficiencies of 1.3%, 0.2%, and 0.2%, respectively. In survival studies, we found that 78% of mice that were irradiated and then transplanted with irradiated/PMVEC-expanded MNCs were alive at day 50, compared with 18% of irradiated control mice (p < 0.05). We also observed that mice transplanted with irradiated/PMVEC-expanded MNCs showed complete hematologic recovery. At 8 weeks post-transplant, we found evidence of Ly 5.1 donor cells in both the bone marrow and the spleen of the transplanted animals, but the levels of engraftment were low (range, 0-5.1%; mean, 1.9%). These results demonstrate that a subpopulation of bone marrow stem cells are capable of surviving the effects of high-dose radiation if these cells are placed in coculture with endothelial cell monolayers.

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