Comparative proteomic analysis of supportive and unsupportive extracellular matrix substrates for human embryonic stem cell maintenance.

Human embryonic stem cells (hESCs) are pluripotent cells that have indefinite replicative potential and the ability to differentiate into derivatives of all three germ layers. hESCs are conventionally grown on mitotically inactivated mouse embryonic fibroblasts (MEFs) or feeder cells of human origin. In addition, feeder-free culture systems can be used to support hESCs, in which the adhesive substrate plays a key role in the regulation of stem cell self-renewal or differentiation. Extracellular matrix (ECM) components define the microenvironment of the niche for many types of stem cells, but their role in the maintenance of hESCs remains poorly understood. We used a proteomic approach to characterize in detail the composition and interaction networks of ECMs that support the growth of self-renewing hESCs. Whereas many ECM components were produced by supportive and unsupportive MEF and human placental stromal fibroblast feeder cells, some proteins were only expressed in supportive ECM, suggestive of a role in the maintenance of pluripotency. We show that identified candidate molecules can support attachment and self-renewal of hESCs alone (fibrillin-1) or in combination with fibronectin (perlecan, fibulin-2), in the absence of feeder cells. Together, these data highlight the importance of specific ECM interactions in the regulation of hESC phenotype and provide a resource for future studies of hESC self-renewal.

Double-free, flow-through flap reconstruction for complex scalp defects: a case report.

This case report describes the use of a double-free, flow-through flap as a valuable tool in reconstruction following oncological resection of a large, fungating, squamous cell carcinoma extending through the scalp, forehead, skull, and dura. An anterolateral thigh flap was utilized to supply: soft tissue for the forehead reconstruction, vascularized fascia lata for the dural repair, and to act vascular conduit to supply a distally placed latissmus dorsi flap for total scalp reconstruction. We believe this is the first time this combination of double-free, flow-through flap design has been published for the reconstruction of complex, composite scalp and calvarial defects.

Vancomycin for the treatment of methicillin-resistant staphylococcal and enterococcal infections in 15 horses.

We retrospectively reviewed the cases of 15 foals and adult horses in which vancomycin was used, alone or in combination with an aminoglycoside, to treat methicillin-resistant staphylococcal and enterococcal infections. Signalment, presenting complaint, history (including history of treatment for the current complaint), results of bacterial culture and antimicrobial susceptibility testing, treatment, and outcome were reviewed. The average vancomycin dosage was 7.5 mg/kg q8h, administered by intravenous infusion over 30 min. The infection resolved in all 7 horses with soft tissue infections and in 6 of the 8 horses with infections involving a bone or a joint, or both. No adverse effects of vancomycin therapy were noted. Although the number of cases is small, our findings suggest that vancomycin, alone or in combination with an aminoglycoside, is safe and effective for the treatment of resistant staphylococcal and enterococcal infections in horses and foals. However, owing to the importance of staphylococci and enterococci in human medicine and the problems with emerging resistance, we recommend that the use of vancomycin in horses be limited to cases in which culture and susceptibility results clearly indicate that this agent is likely to be effective and in which there is no reasonable alternative.

Odds of moderate or severe gastric ulceration in racehorses receiving antiulcer medications.

OBJECTIVE: To determine the odds of moderate or severe gastric ulceration in racehorses treated with various antiulcer medications. DESIGN: Unmatched case-control study. ANIMALS: 798 horses in active race training (252 Thoroughbreds and 546 Standardbreds). Only horses that had been receiving a single antiulcer medication or no antiulcer medication for at least 2 weeks prior to examination were included. PROCEDURE: Gastroscopy was performed on each horse by a single individual who was not aware of the horses' antiulcer treatments, and severity of gastric ulceration was scored. Signalment and medication history were recorded. Logistic regression was used to determine whether identification of moderate or severe ulceration was associated with treatment, age, breed, or sex. Treatments were grouped as no treatment, buffer, sucralfate, histamine type 2 receptor antagonist, compounded omeprazole, proprietary omeprazole at a low dosage, and proprietary omeprazole at a high dosage. RESULTS: Only proprietary omeprazole was associated with significantly lower odds of moderate or severe ulceration, compared with no treatment. Risks of moderate or severe gastric ulceration in horses receiving a buffer, sucralfate, a histamine type 2 receptor antagonist, or compounded omeprazole were not significantly different from risks in horses receiving no antiulcer medication. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the proprietary formulation of omeprazole was associated with a significantly lower risk of moderate or severe gastric ulceration, compared with no treatment, in racehorses in active race training, whereas other antiulcer medications were not.