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Biomedical subjects

Susan Schneider

Publications and source records attributed to Susan Schneider.

26 records · Page 2Linked to original sources
PubMed2003

Visualizing vitreous using Kenalog suspension.

We developed and evaluated a method of visualizing vitreous gel in the anterior segment. In this study, 0.2 mL of injectable triamcinolone (Kenalog) 40 mg/mL was captured in a 5 microm filter and rinsed with 2 mL of balanced salt solution (BSS). It was then resuspended in 5 mL of BSS and recaptured to thoroughly remove the preservative. The Kenalog particles were ultimately resuspended in 2 mL of BSS and injected into the anterior chamber through a 27-gauge cannula. Kenalog particles were trapped on and within the vitreous gel, making it clearly visible. The visualization provided direct observation of vitreous behavior in various experimental settings and assisted surgeons intraoperatively in the identification and removal of vitreous in the anterior segment.

Acetates↗
PubMed2003

Indocyanine green staining of anteriorly placed zonules.

The anatomy of the capsules and zonules varies with each patient, particularly in the zonule-free zone. We present a case in which indocyanine green dye highlighted the anterior lens capsule and centrally encroaching zonular fibers within a 2.0 mm zonule-free zone. We suggest technique modifications to reduce the risk for capsule extensions and related complications.

Adult↗
PubMed2003

Effects of leukocyte depletion filters on matrix metalloproteinase activation in an extracorporeal circulation circuit.

Matrix metalloproteinases (MMPs) are a family of endopeptidases that function to remodel tissue during both normal physiology and pathology. Research performed by the Medical University of South Carolina found an increased release of several MMP species during cardiopulmonary bypass (CPB), including the subtype MMP-9, but whether and to what degree the extracorporeal circulation circuit (ECC) induces the release of MMPs has yet to be determined. Human bank whole blood scheduled for discard was obtained and exposed to an ECC. The first set of studies (N = 8) was performed with a loop circuit using a standard arterial line filter. A leukoreduction filter was incorporated during the first 30 min of the pump run for the second set of trials; the leukoreduction filter was then bypassed and a standard arterial filter used for the remaining 60 minutes on pump (N = 8). Blood samples were drawn at four time points for analysis (baseline, 30, 60, and 90 min). Data were analyzed using repeated measures analysis of variance with between-subjects factors, and a p value of less than .1 was considered statistically significant. The MMP-9 level increased by 130.44% at 90 min on pump in the standard arterial filter group and decreased by 34.62% at 90 min on pump in the leukoreduction group. There was a significant difference between the baseline MMP-9 level and the MMP-9 concentrations at 30, 60, and 90 min for both groups (p = .0348); there was a significant difference in MMP-9 levels between the two filter groups (p = .0611). The present study found a significant increase in MMP-9 levels when blood was exposed to an ECC with a standard arterial filter. The use of a leukoreduction filter significantly reduced MMP-9 concentrations as compared to baseline levels in this study. Leukocyte depletion filtration may serve to benefit CPB patients by attenuating the inflammatory response and disrupting pathways that govern such mediators as the MMPs.

Enzyme Activation↗
PubMed2002

Diagnostic transvitreal fine-needle aspiration biopsy of small melanocytic choroidal tumors in nevus versus melanoma category.

PURPOSE: To report an experience with fine-needle aspiration biopsy of selected small melanocytic choroidal tumors during the interval from April 13, 1983, through January 19, 2001. METHODS: Retrospective descriptive case series report of 34 patients with a small melanocytic choroidal tumor (maximal diameter, < or = 10 mm; thickness, > or = 1.5 mm but < or = 3 mm) evaluated diagnostically by transvitreal fine-needle aspiration biopsy prior to treatment. None of the tumors had invasive features at the time of biopsy. RESULTS: Patients ranged in age from 26 to 73 years (mean, 50.9 years). The evaluated choroidal tumors had a mean maximal basal diameter of 8.0 mm and a mean maximal thickness of 2.4 mm. Eighteen of the 34 tumors (52.9%) had been documented to enlarge prior to biopsy. Biopsy was performed in all cases using a 25-gauge hollow lumen needle and a transvitreal approach via a pars plana puncture site. The biopsy yielded a sufficient aspirate for cytodiagnosis in 22 of 34 cases (64.7%). In these cases, the tumor was classified as malignant melanoma in 16 (47.1% of total), intermediate lesion in 4 (11.8%), and benign nevus in 2 (5.9%). The 12 tumors that yielded an insufficient aspirate and the four lesions that yielded intermediate cells continued to be classified as "nevus versus melanoma" and were monitored periodically for growth or other changes. Four of the 12 tumors that yielded an insufficient aspirate for cytodiagnosis and all four lesions that yielded intermediate cells were eventually reclassified as small choroidal melanomas and treated. The remaining eight tumors that yielded an insufficient aspirate and the two tumors that yielded benign nevus cells were classified as benign nevi at the most recent follow-up evaluation. CONCLUSIONS: Fine-needle aspiration biopsy showed that a substantial proportion of small melanocytic choroidal tumors likely to be classified clinically as small choroidal melanomas in many centers were in fact benign nevi or intermediate lesions.

Adult↗
PubMedDate not supplied

Gefitinib (Iressa, ZD1839) and tyrosine kinase inhibitors: the wave of the future in cancer therapy.

Targeted therapies are one of the latest innovative trends in cancer therapy. The epidermal growth factor receptor (EGFR) is a target found in high concentrations in several solid tumors including lung, breast, colorectal, and brain. Tyrosine kinase inhibitors, such as gefitinib (Iressa, ZD1839), block the EGFR. As a result, there is inhibition of cellular proliferation, promotion of apoptosis, and inhibition of anti-angiogenesis. Gefitinib has demonstrated significant efficacy in non-small-cell lung cancer (NSCLC), leading to FDA approval for treatment of this refractory disease. Phase 2 trials with gefitinib for platinum refractory NSCLC reported disease response and symptom improvement. Early results of phase 2 studies of gefitinib, combined with standard chemotherapy in colorectal cancer, showed a 75% response rate compared with 55% with standard therapy alone. Gefitinib, combined with flutamide, produced an additive growth inhibition in prostate cancer. A phase 2 trial of gefitinib in first-relapse glioblastoma multiforme demonstrated median overall survival from treatment start of 39.4 weeks compared with 40 weeks with standard chemotherapy. Gefitinib is an oral agent with a mild toxicity profile, and thus, may be an optimal addition to chemotherapeutic regimens for some solid tumors. Gefitinib is potentially a vital and useful weapon in the arsenal of cancer therapies.

Administration, Oral↗
PubMedDate not supplied

Pseudomonas aeruginosa endogenous endophthalmitis with choroidal abscess in a patient with cystic fibrosis.

PURPOSE: To describe the clinical presentation, management, and outcome of a case of endogenous intraocular infection due to Pseudomonas aeruginosa in a patient with cystic fibrosis (CF). METHODS: The authors describe a case of an adult patient with CF who developed an intraocular infection by P. aeruginosa. RESULTS: Diagnosis was confirmed by culture of purulent fluid obtained by transcleral incision and drainage. The infection persisted in spite of aggressive surgical intervention including extensive endoresection of the visibly affected retina and choroid and multiple administrations of appropriate intraocular, subconjunctival, and systemic antibiotics. Eventually, the eye became blind and painful and was enucleated. CONCLUSIONS: Endogenous intraocular infection by P. aeruginosa can occur in patients with CF who have not undergone lung transplantation. An infection of this type may be impossible to eradicate by aggressive surgical intervention and appropriate antibiotic therapy.

Abscess↗
PubMedDate not supplied

Peribulbar oncocytoma: high-frequency ultrasound with histopathologic correlation.

The clinical, ultrasonographic, and histopathologic characteristics of an oncocytoma of the conjunctiva are described. A 49-year-old woman presented with a red-orange lesion adjacent to the caruncle in her left eye. A clinical examination including high-frequency ultrasound was performed prior to excisional biopsy of her tumor. High-frequency ultrasound demonstrated an epibulbar tumor with low internal reflectivity and a cystic component. There was no involvement of the underlying sclera. Multiple hypoechoic components of the tumor stroma were correlated to multiple cystic glandular structures on histopathologic evaluation. The excised tumor was diagnosed to be an oncocytoma.

Adenoma, Oxyphilic↗