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Biomedical subjects

R E Foster

Publications and source records attributed to R E Foster.

At least 19 recordsLinked to original sources
PubMed2001

Progressive outer retinal necrosis syndrome in a lymphoma patient with good visual outcome.

PURPOSE: To report an HIV-negative lymphoma patient who developed progressive outer retinal necrosis syndrome and who had a good visual outcome after treatment with two-drug antiviral therapy and intravenous immunoglobulin. METHODS: Case report. RESULTS: A 43-year-old man with small lymphocytic lymphoma was diagnosed with progressive outer retinal necrosis in his left eye. Treatment was initiated with intravenous foscarnet and ganciclovir as well as intravenous gammaglobulin at a dose of 0.5 gm/kg per day for 5 days. On the second hospital day he was started on decadron 4 mg orally four times daily. No further posterior retinitis progression was observed despite severe immunosuppression. Visual acuity remained stable at 20/30 with 10 months' follow-up. CONCLUSIONS: The benefit of using gammaglobulin in progressive outer retinal necrosis is unknown. Given the rapid improvement seen in this patient's retinitis, it may be reasonable to consider the use of gammaglobulin in other cases of infectious retinitis in immunocompromised patients.

Adult↗
PubMed2001

Indocyanine green-assisted peeling of the retinal internal limiting membrane during vitrectomy surgery for macular hole repair.

OBJECTIVE: To determine the efficacy and safety of indocyanine green (ICG)-assisted retinal internal limiting membrane (ILM) peeling during macular hole repair. DESIGN: Interventional, noncomparative, prospective case series. PARTICIPANTS: Twenty-four consecutive patients (24 eyes) with stage 3 or 4 macular holes. INTERVENTION: All eyes underwent a pars plana vitrectomy, including peeling of the posterior cortical hyaloid when necessary. Indocyanine green dye (0.5%) was instilled into the posterior vitreous cavity over the macula and left in place for 3 to 5 minutes. After removal of the ICG, the retinal ILM was peeled. Medium- to long-acting gas tamponade was used in all cases, and all patients were asked to position face down for 1 to 2 weeks. MAIN OUTCOME MEASURES: Intraoperative staining properties of ICG, technical ease of peeling of the retinal ILM, postoperative anatomic results, visual acuity, and complications were recorded. RESULTS: Indocyanine green stained the retinal ILM, but did not stain the underlying retina. Indocyanine green staining greatly facilitated the surgeons' ability to visualize and peel the ILM in each case. Peeled tissue was sent for both light and electron microscopic studies, which confirmed that the ICG-stained tissue was truly retinal ILM. Patients were observed after surgery for an average of 123 days (range, 23-195 days). Anatomic closure of the macular hole was achieved in 21 eyes (88%) with a single surgery. Visual acuity improved in 23 of 24 patients (96%) after surgery. There were no intra- or postoperative complications related to ICG use, and there was no clinical or fluorescein angiographic evidence of ICG toxicity. CONCLUSIONS: Indocyanine green stains the retinal ILM. This property facilitates ILM peeling by providing a stark contrast between the stained ILM and the unstained retina. Indocyanine green staining of the ILM appears to be a safe and useful adjunct in vitreous surgery for macular hole repair.

Adult↗
PubMed2000

Echographic features of medulloepithelioma.

PURPOSE: To evaluate the echographic features of medulloepithelioma that may assist in establishing the diagnosis. METHODS: Retrospective review identified four eyes with medulloepithelioma studied with echography. Clinical records, echographic findings, histopathologic tumor features, and the clinical course were reviewed. RESULTS: The initial preoperative diagnosis of medulloepithelioma was uncertain, based on clinical findings alone in three cases but was accurate when echographic findings were combined with clinical findings in all four cases. Cysts posterior to the iris were detected on clinical examination in only two cases, but were revealed on echography in all four cases. Additional echographic findings included irregular high internal reflectivity (n = 4), irregular tumor surface (n = 3), molding around intraocular structures (n = 3), and internal vascularity (n = 2). CONCLUSIONS: The diagnosis of medulloepithelioma is not always apparent on clinical examination alone. Echographic findings of a highly reflective, irregularly structured tumor with associated cystic changes involving the ciliary body region may help establish a presumed diagnosis of medulloepithelioma.

Anterior Eye Segment↗
PubMed2000

Indocyanine green-assisted peeling of the retinal internal limiting membrane.

OBJECTIVE: To determine whether indocyanine green (ICG) stains and facilitates peeling of the retinal internal limiting membrane (ILM). To investigate the different staining properties of the posterior cortical hyaloid, retinal ILM, and the retina after ILM removal. DESIGN: Autopsy eye study. MATERIALS: Eleven human cadaveric eyes. METHODS: Open sky vitrectomy including removal of the posterior cortical vitreous was performed. A 0.5% ICG solution was then injected into the posterior vitreous cavity over the macula. The dye was allowed to settle on the macula for 5 minutes and was then removed by mechanical aspiration. Peeling of the ILM was initiated with a bent needle and completed with intraocular forceps. Specimens were submitted for light and electron microscopy. MAIN OUTCOME MEASURES: Staining properties and ease of peeling of retinal ILM were evaluated. Retinal ILM removal was confirmed by histopathologic and electron microscopic examination. RESULTS: ICG contact with the retinal surface resulted in bright green staining of the ILM. This stain greatly facilitated ILM peeling by improving direct visualization of the membrane. The underlying retina did not stain, thus providing a clear distinction between the stained ILM and the unstained retina. Continuous circular peeling of the ILM was easily completed with this technique. Light microscopic and ultrastructural studies confirmed removal of the ILM. CONCLUSIONS: ICG solution distinctly stains the nearly invisible retinal ILM in human cadaveric eyes. ICG staining greatly facilitates ILM peeling by providing a stark contrast between the stained ILM and the unstained retina.

Basement Membrane↗
PubMed2000

Management of glaucoma implants occluded by vitreous incarceration.

PURPOSE: To review the authors' experience in the management of aphakic or pseudophakic patients without an intact posterior capsule who had undergone glaucoma implant surgery complicated by vitreous incarceration in the tube, resulting in increased intraocular pressure or combined rhegmatogenous and tractional retinal detachment. METHODS: Retrospective review of the clinical features, treatment, and outcomes of eight patients who had vitreous incarceration in a glaucoma implant drainage tube. In each patient, a model 425 (7 patients) or model 350 (1 patient) Baerveldt glaucoma implant was used. RESULTS: Vitreous incarceration in the tube was first diagnosed 1 day to 49 weeks after surgery (mean, 7.5 weeks; median, 1 week). The interval between glaucoma implant surgery and pars plana vitrectomy ranged from 22 to 365 days (mean, 125 days). Before management with pars plana vitrectomy or neodymium:yttrium-aluminum-garnet laser vitreolysis, intraocular pressure ranged from 25 to 62 mm Hg (mean, 40 mm Hg). Four patients were initially treated with neodymium:yttrium-aluminum-garnet laser vitreolysis, which was successful in only one patient. Six patients were successfully treated with pars plana vitrectomy, and one patient declined surgery. Follow-up after treatment of the incarceration ranged from 5 weeks to 15 months (mean, 8.3 months). After pars plana vitrectomy, intraocular pressure ranged from 9 to 24 mm Hg (average, 14 mm Hg). Postoperative visual acuity remained within one line of the preoperative visual acuity in each of the six patients undergoing pars plana vitrectomy. CONCLUSIONS: Pars plana vitrectomy is effective in managing vitreous incarceration in glaucoma implant tubes. Previous anterior vitrectomy does not prevent incarceration.

Adult↗
PubMed2000

Effect of insecticides on the diamondback moth (Lepidoptera: Plutellidae) and its parasitoid Diadegma insulare (Hymenoptera: Ichneumonidae).

Studies were conducted to evaluate the toxicity of insecticides to adult Diadegma insulare (Cresson) and its host the diamondback moth, Plutella xylostella (L.). Leaf-dip and direct-dip bioassays for diamondback moth larvae and residual bioassays for adults of diamondback moth and D. insulare were used to assess mortalities. Larval mortalities at field rates were significantly higher with carbaryl, permethrin, spinosad, and tebufenozide when compared with Bacillus thuringiensis, or imidacloprid in the larval-dip bioassay 72 h after treatment. In the leaf-dip and residual bioassays, both permethrin and spinosad caused 100% mortalities to diamondback moth larvae and adults, respectively, 72 h after treatment. Of all the materials tested, only B. thuringiensis and tebufenozide were not toxic to D. insulare 24 h after treatment. Spinosad was not toxic to D. insulare 30 min after treatment. However, 100% mortality was observed 8 h after treatment.

Animals↗
PubMed1998

Development of a multiple-drug delivery implant for intraocular management of proliferative vitreoretinopathy.

A prototype multiple-drug delivery implant has been developed for the intraocular management of proliferative vitreoretinopathy (PVR). Because of the recurrent nature of the disease, PVR causes blindness in approximately 7% of patients who have undergone retinal re-attachment surgery. The poly(dl-lactide-co-glycolide) 50/50 (PLGA) implant consists of three cylindrical segments, each of which contains one of the following drugs: 5-fluorouridine (5FUrd, an antimetabolite), triamcinolone (Triam, a corticosteroid), and human recombinant tissue plasminogen activator (t-PA, a thrombolytic agent). The device can be inserted through a 20-gauge syringe needle into the vitreous body of the eye. The implant also possesses a PLGA coating over the t-PA-containing terminal segment, which creates a lag-time to deliver t-PA when most needed and to decrease the risk of postoperative bleeding. Two methods of cylinder fabrication were investigated: heat and solvent extrusion. The release behavior of several drugs was examined as a function of the processing variables including: extrusion method, drug loading, polymer molecular weight, and drug particle size. The presence of either the organic solvent (acetone) during processing or a highly water-soluble drug (5FUrd) in the formulation increased the polymer porosity, which in turn, increased the drug release-rate. Drug loading effects were consistent with percolation concepts, and a low-molecular-weight PLGA (e.g., Mw=42000 for inherent viscosity=0.58 dl/g) was desirable to produce controlled release close to one month. Based on pharmacological and pharmacokinetic data of these compounds and our clinical experience with this disease, several design criteria for a combined implant were devised. Optimal cylindrical segments from the formulation studies were selected and combined in series to form a contiguous implant. After successful combination and coating procedures were developed, prototype implants were prepared. From the 3-drug prototype, 5FUrd and Triam were released approximately 1 microgram/day for over 4 weeks and 10-190 microgram/day over 2 weeks, respectively. The solvent-extrusion procedure did not significantly alter the stability of the encapsulated t-PA (>94+/-5% serine protease activity after preparation). After a lag-time of approximately 2 days, t-PA was released active at a rate of approximately 0.2-0.5 microgram/day in approximately 2 weeks. The release characteristics from the combined implant largely met our initial design criteria. Hence, controlled-release implants of this kind may have potential use for intraocular treatment of PVR.

Chromatography, High Pressure Liquid↗
PubMed1998

Evaluation of hibernating myocardium in patients with ischemic heart disease.

Patients with ischemic heart disease and significant left ventricular dysfunction are often difficult to manage medically. Revascularization procedures may improve left ventricular function and prognosis in this population if hypocontractile yet viable myocardium (hibernating myocardium) is demonstrated. Nuclear cardiology studies (single photon and positron methods), two-dimensional echocardiography, and magnetic resonance imaging studies have been utilized to identify hibernating myocardium. If thallium-201 studies are performed, the use of reinjection of thallium and repeat imaging improves the sensitivity of these studies for the detection of viable myocardium. Dobutamine echocardiographic studies may have a higher specificity and positive predictive value for the subsequent improvement of regional systolic left ventricular function after revascularization than the nuclear techniques. However, thallium studies have an excellent negative predictive value. Positron emission tomography (PET) allows the simultaneous assessment of perfusion and metabolic activity; however, these studies are expensive and not widely available. Functional evaluation with PET is in its infancy. Functional cardiac magnetic resonance imaging (MRI), although not widely available yet, provides the most accurate evaluation of regional ventricular function. MRI spectroscopy may be utilized to assess myocardial viability. As acquisition times improve and "real-time" imaging becomes a reality, MRI and MRI spectroscopy will likely become very accurate tools for assessing functional reserve and metabolic activity. The selection of the most appropriate method for assessment of myocardial viability will include consideration of a patient's characteristics, the presence of coronary arterial tree amenable to revascularization techniques, the techniques available to the clinician to assess viability, and local revascularization experience in this population. The result of an individual patient's evaluation is relevant to the consideration of coronary revascularization, or if this is not possible, cardiac transplantation.

Echocardiography↗
PubMed1998

Long-term follow-up of extracapsular cataract extraction and posterior chamber intraocular lens implantation in patients with uveitis.

OBJECTIVE: The objective of the study was to determine the long-term outcome of patients with uveitis who underwent extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens (PCIOL) implantation. DESIGN: Retrospective review. PARTICIPANTS: Twenty-eight patients (36 eyes). INTERVENTION: Extracapsular cataract extraction and PCIOL implantation. MAIN OUTCOME MEASURES: Level of best-corrected Snellen visual acuity, change in visual acuity, length of follow-up, long-term findings, and complications. RESULTS: In long-term follow-up (mean, 81.4 months), 94% of eyes had visual acuity improvement compared with preoperative levels. Average change in visual acuity for all eyes was an improvement of 6.4 Snellen lines; 75% of eyes were 20/40 or better. The prevalences of cystoid macular edema (CME), epiretinal membrane (ERM), and posterior capsule opacification (PCO) were 56%, 56%, and 58%, respectively. CONCLUSIONS: Patients with uveitis who are treated with ECCE with PCIOL implantation can have successful visual results in long-term follow-up despite the prevalence of PCO or macular abnormalities such as CME and ERM.

Cataract↗
PubMed1998

Changes in left ventricular mass and volumes in patients receiving angiotensin-converting enzyme inhibitor therapy for left ventricular dysfunction after Q-wave myocardial infarction.

OBJECTIVES: We evaluated global and segmental left ventricular (LV) mass and LV mass/volume ratio in patients with LV dysfunction receiving angiotensin-converting enzyme (ACE) inhibitor therapy after acute myocardial infarction (MI). BACKGROUND: ACE inhibitors attenuate LV dilatation and compensatory hypertrophy after acute MI in animal models. However, LV remodeling in patients after acute MI has been largely defined on the basis of changes in chamber volume alone. METHODS AND RESULTS: Twenty-nine patients with LV ejection fraction <40% received the ACE inhibitor ramipril (range 2.5 to 20 mg/day) within 5 days of their first Q-wave MI. Magnetic resonance imaging was performed at baseline and at 3 months, providing global and regional LV volumes and mass from summated serial short-axis slices. Mean arterial blood pressure was unchanged from baseline to 3-month follow-up (89 +/- 10 to 92 +/- 17 mm Hg). LV mass decreased (90 +/- 25 to 77 +/- 21 gm/m2, p < 0.0005) as LV end-diastolic volumes increased (65 +/- 13 to 73 +/- 22 ml/m2, p < 0.01). Global LV mass to volume ratio decreased from 1.40 +/- 0.28 to 1.08 +/- 0.18 gm/ml (p < 0.0001), as did circumferential wall thickness to volume ratio of noninfarcted myocardium at the base of the LV (0.06 +/- 0.02 to 0.05 +/- 0.02 mm/ml, p < 0.001). LV ejection fraction increased from 35 +/- 6 to 40 +/- 9% (p < 0.001) in the presence of an increase in calculated end-systolic wall stress (185 +/- 57 to 227 +/- 54 gm/cm2, p < 0.01). CONCLUSIONS: ACE inhibitor therapy was associated with improved LV function in the face of a decrease in mass to volume ratio of the LV as well as a decrease in wall thickness to volume ratio of noninfarcted myocardium. Whether ACE inhibitor therapy had direct or indirect effects on these changes in LV mass and function are open questions that require further investigation.

Adult↗
PubMed1997

Rapid cardiac imaging with turbo BRISK.

A variety of variable and constant rate, sparse sampling strategies have previously been proposed to rapidly image dynamically changing objects. The majority of these strategies compile a k-space data set for any given time point by substituting k-space data from the most recently sampled time positions (extracted from the sparsely sampled set). The BRISK technique, is a variable rate, sparse sampling technique which additionally incorporates an interpolation scheme to more accurately represent k-space data at positions which were not directly sampled. Here, strategies are introduced that allow tubo concepts to be incorporated with BRISK. Simulations are conducted to compare the efficacy of the turbo BRISK acquisition and processing strategy against a constant rate, sparse sampling strategy with direct substitution of the most recently acquired k-space lines. It is shown that turbo BRISK generates images of similar quality in approximately half the time as the uniform sampling rate, sparse sampling strategy. Data from turbo BRISK acquisitions of multicardiac phase image sets, obtained on a normal volunteer and cardiac patients are presented.

Heart↗
PubMed1997

Common k-space acquisition: a method to improve myocardial grid-tag contrast.

A current limitation of many myocardial tag acquisitions employing SPAMM encoding is the relatively rapid loss of tag contrast over the cardiac cycle. Acquisition schemes that apply line tags produce prolonged tag contrast compared with directly excited grid tags. However, a grid-tag series can be generated by combining two orthogonal line-tag series. To be time efficient, each line-tag series can be acquired with the read gradient oriented perpendicular to the line-tag direction. There are several disadvantages associated with this approach, including the requirement to avoid signal fold-over and that fat shift artifacts appear in different directions in each line-tag series. Presented here is a method of applying separate line tags that does not require interchanging the read and phase encoding gradients and does not extend the scan time compared with a conventional grid-tag acquisition. Additionally, the means of generating grid tags results in a doubling of the tag contrast to noise ratio compared a line-tag set. Computer simulations are presented along with phantom and volunteer scans.

Heart↗
PubMed1997

Leukocoria caused by occult penetrating trauma in a child.

PURPOSE: To report a child with leukocoria caused by occult penetrating trauma. METHODS: Case report. The clinical findings and surgical repair of acquired leukocoria of the right eye in a 2-year-old boy are presented. RESULTS: In the right eye, slit-lamp examination disclosed a retrolenticular cyclitic membrane and moderately severe (3+) cells and flare anterior chamber reaction. The eye was hypotonous, and B scan showed that the membrane was associated with a retinal detachment. Surgery was performed to repair the retinal detachment and to remove the retrolenticular membrane. Two months before initial examination, the patient had been attacked by a rooster. CONCLUSION: Occult penetrating trauma should be considered in the differential diagnosis of pediatric leukocoria.

Animals↗
PubMed1997

Angiotensin-converting enzyme inhibitor therapy affects left ventricular mass in patients with ejection fraction > 40% after acute myocardial infarction.

OBJECTIVES: We tested the hypothesis that angiotensin-converting enzyme (ACE) inhibitor therapy decreases left ventricular (LV) mass in patients with a left ventricular ejection fraction (LVEF) > 40% and no evidence of heart failure after their first acute Q wave myocardial infarction (MI). BACKGROUND: Recently, ACE inhibitor therapy has been shown to have an early mortality benefit in unselected patients with acute MI, including patients without heart failure and a LVEF > 35%. However, the effects on LV mass and volume in this patient population have not been studied. METHODS: Thirty-five patients with a LVEF > 40% after their first acute Q wave MI were randomized to titrated oral ramipril (n = 20) or conventional therapy (control, n = 15). Magnetic resonance imaging (MRI) performed an average of 7 days and 3 months after MI provided LV volumes and mass from summated serial short-axis slices. RESULTS: Left ventricular end-diastolic volume index did not change in ramipril-treated patients (62 +/- 16 [SD] to 66 +/- 17 ml/m2) or in control patients (62 +/- 16 to 68 +/- 17 ml/m2), and stroke volume index increased significantly in both groups. However, LV mass index decreased in ramipril-treated patients (82 +/- 18 to 73 +/- 19 g/m2, p = 0.0002) but not in the control patients (77 +/- 15 to 79 +/- 23 g/m2). Systolic arterial pressure did not change in either group at 3-month follow-up. CONCLUSIONS: In patients with a LVEF > 40% after acute MI, ramipril decreased LV mass, and blood pressure and LV function were unchanged after 3 months of therapy. Whether the decrease in mass represents a sustained effect that is associated with a decrease in morbid events requires further investigation.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Acute posterior multifocal placoid pigment epitheliopathy after acute group A streptococcal infection.

PURPOSE: We studied a case of acute posterior multifocal placoid pigment epitheliopathy in a 40-year-old man who had had an acute febrile illness. METHODS: The medical record was reviewed for clinical manifestations, course of disease, and laboratory findings, including results of fluorescein and indocyanine green angiography. RESULTS: The patient had the typical clinical course of acute posterior multifocal placoid pigment epitheliopathy with spontaneous resolution of posterior pole lesions and improvement in visual acuity from 20/60 to 20/20. The laboratory evaluation was remarkable for a rise in the anti-DNAse B antibody titer between initial and convalescent-phase serum samples, providing evidence of recent group A streptococcal infection. CONCLUSION: Although acute posterior multifocal placoid pigment epitheliopathy is often attributed to a postviral condition, this syndrome may also develop after an acute group A streptococcal infection.

Acute Disease↗
PubMed1996

Treatment of clinically resistant cytomegalovirus retinitis with combined intravitreal injections of ganciclovir and foscarnet.

PURPOSE: To determine the efficacy of combined ganciclovir and foscarnet intravitreal injections in controlling clinically resistant cytomegalovirus retinitis in a 37-year-old man with the acquired immunodeficiency syndrome who refused systemic therapy. METHODS: The patient refused systemic therapy and was treated with intravitreal injections of ganciclovir and foscarnet, which were then combined when the retinitis became resistant to either drug alone. RESULTS: The retinitis was initially controlled with bilateral intravitreal ganciclovir injections. After reactivation of retinitis in the left eye, intravitreal foscarnet was effective until recurrent retinitis threatened the center of the fovea. The retinitis continued to progress until combined intravitreal injections of ganciclovir and foscarnet were administered. CONCLUSIONS: Combined intravitreal injections of ganciclovir and foscarnet may be effective in treating cytomegalovirus retinitis when the infection is clinically resistant to either intravitreal drug alone. Intravitreal injections can be effective in controlling cytomegalovirus retinitis in patients who are intolerant of or refuse systemic therapy.

AIDS-Related Opportunistic Infections↗