Biomedical subjects

Mitchell Weaver

Publications and source records attributed to Mitchell Weaver.

3 recordsLinked to original sources

PubMed2006

Adventitial delivery of dominant-negative p67phox attenuates neointimal hyperplasia of the rat carotid artery.

Several essential components of NADPH oxidase, including p22phox, gp91phox (nox2) and its homologs nox1 and nox4, p47phox, p67phox, and rac1, are present in the vasculature. We previously reported that p67phox is essential for adventitial fibroblast NADPH oxidase O2- production. Thus we postulated that inhibition of adventitial p67phox activity would attenuate angioplasty-induced hyperplasia. To test this hypothesis, we treated the adventitia of carotid arteries with a control adenovirus (Ad-control), a virus expressing dominant-negative p67phox (Ad-p67dn), or a virus expressing a competitive peptide (gp91ds) targeting the p47phox-gp91phox interaction (Ad-gp91ds). Common carotid arteries (CCAs) from male Sprague-Dawley rats were transfected with Ad-control, Ad-p67dn, or Ad-gp91ds in pluronic gel. After 2 days, a 2-F (Fogarty) catheter was used to injure CCAs in vivo. After 14 days, CCAs were perfusion-fixed and analyzed. In 13 experiments, digital morphometry suggested a reduction of neointimal hyperplasia with Ad-p67dn compared with Ad-control; however, the reduction did not reach statistical significance (P = 0.058). In contrast, a significant reduction was achieved with Ad-gp91ds (P = 0.006). No changes in medial area or remodeling were observed with either treatment. Moreover, adventitial fibroblast proliferation in vitro was inhibited by Ad-gp91ds but not by Ad-p67dn, despite confirmation that Ad-p67dn inhibits NADPH oxidase in fibroblasts. These data appear to suggest that a multicomponent vascular NADPH oxidase plays a role in neointimal hyperplasia. However, inhibition of p47phox may be more effective than inhibition of p67phox at attenuating neointimal growth.

Animals↗

PubMed2004

Evaluation of gastrointestinal stromal tumors for recurrence rates and patterns of long-term follow-up.

Retrospective chart review of 33 patients with gastrointestinal stromal tumors (GISTs) over the past 14 years was performed. Clinicopathologic variables were analyzed for patterns affecting tumor recurrence and need for long-term follow-up. No recurrence was found in the benign group and tumors <5 cm. In the malignant group, recurrence rate was 53 per cent with a mean follow-up of 34 months. Mean time to diagnosis of recurrence was 16 months. Eighty per cent of recurrences occurred within 2 years of surgical resection. Sixty per cent of recurrences were asymptomatic. Systematic follow-up consisted of physical examination and CT scans at 6-month intervals for 2 years after surgery. Time to diagnosis of a recurrence after surgery was 13 months for systematic follow-up and 18 months for sporadic follow-up. Mean survival was 24 months in both groups. Most recurrences occur within 2 years of surgical resection. Symptomatology does not provide early diagnosis. Patients who had systematic follow-up were diagnosed sooner with recurrence. Therefore, we recommend systematic follow-up after surgical resection of a malignant GIST to include physical examination and CT scan at 6-month intervals for up to 2 years after surgery with repeat CT scan at 3 years.

Adult↗

PubMed2003

Partial splenectomy using a coupled saline-radiofrequency hemostatic device.

BACKGROUND: Partial splenectomy is indicated for benign tumors and cysts of the spleen, as well as, operative management of splenic trauma limited to one pole of the spleen. Despite improved technique, bleeding from the cut surface of the spleen still remains an obstacle. METHODS: We describe our technique for partial splenectomy using a new device based on coupling saline with radiofrequency energy to achieve hemostasis while dividing the splenic parenchyma. RESULTS: Use of this technique has led to blood loss of less than 50 cc, while achieving splenic preservation.

Blood Loss, Surgical↗