Magnetic resonance mapping demonstrates benefits of VEGF-induced myocardial angiogenesis.

Coronary occlusive disease is the leading cause of death in industrial nations and affects one in four adults. Although heart attacks are caused by occlusion of a coronary artery, some patients have occlusions without infarction because they have sufficient collateral vessels providing an alternate pathway for blood supply. Vascular endothelial growth factor (VEGF) is an angiogenic peptide that can stimulate collateral vessel development in the ischaemic myocardium. We used magnetic resonance imaging (MRI) and image processing to identify and quantify non-invasively the benefits related to VEGF infusion on collateral development in the heart. This was accomplished as a placebo-controlled study in the porcine model of chronic ischaemia that most closely mimics the human pathophysiology of progressive coronary occlusion. Image series converted to a space-time map demonstrated that with treatment the ischaemic zone was smaller and the contrast arrival delay was less, which resulted in better ejection fraction and regional wall thickening. These findings demonstrate in a manner applicable to humans, that VEGF improves collateral blood supply, resulting in improved cardiac global and regional function after and in spite of coronary artery occlusion.

Decreased expression of myotonin-protein kinase messenger RNA and protein in adult form of myotonic dystrophy.

The myotonic dystrophy mutation has recently been identified; however, the molecular mechanism of the disease is still unknown. The sequence of the myotonin-protein kinase gene was determined, and messenger RNA spliced forms were identified in various tissues. Antisera were developed for analytical studies. Quantitative reverse transcription-polymerase chain reaction and radioimmunoassay were used to demonstrate that decreased levels of the messenger RNA and protein expression are associated with the adult form of myotonic dystrophy.

Expression of the murine Duchenne muscular dystrophy gene in muscle and brain.

Complementary DNA clones were isolated that represent the 5' terminal 2.5 kilobases of the murine Duchenne muscular dystrophy (Dmd) messenger RNA (mRNA). Mouse Dmd mRNA was detectable in skeletal and cardiac muscle and at a level approximately 90 percent lower in brain. Dmd mRNA is also present, but at much lower than normal levels, in both the muscle and brain of three different strains of dystrophic mdx mice. The identification of Dmd mRNA in brain raises the possibility of a relation between human Duchenne muscular dystrophy (DMD) gene expression and the mental retardation found in some DMD males. These results also provide evidence that the mdx mutations are allelic variants of mouse Dmd gene mutations.

Local perivascular delivery of basic fibroblast growth factor in patients undergoing coronary bypass surgery: results of a phase I randomized, double-blind, placebo-controlled trial.

BACKGROUND: Angiogenesis is a promising treatment strategy for patients who are not candidates for standard revascularization, because it promotes the growth of new blood vessels in ischemic myocardium. METHODS AND RESULTS: We conducted a randomized, double-blind, placebo-controlled study of basic fibroblast growth factor (bFGF; 10 or 100 microg versus placebo) delivered via sustained-release heparin-alginate microcapsules implanted in ischemic and viable but ungraftable myocardial territories in patients undergoing CABG. Twenty-four patients were randomized to 10 microg of bFGF (n=8), 100 microg of bFGF (n=8), or placebo (n=8), in addition to undergoing CABG. There were 2 operative deaths and 3 Q-wave myocardial infarctions. There were no treatment-related adverse events, and there was no rise in serum bFGF levels. Clinical follow-up was available for all patients (16.0+/-6.8 months). Three control patients had recurrent angina, 2 of whom required repeat revascularization. One patient in the 10-microg bFGF group had angina, whereas all patients in the 100-microg bFGF group remained angina-free. Stress nuclear perfusion imaging at baseline and 3 months after CABG showed a trend toward worsening of the defect size in the placebo group (20.7+/-3.7% to 23.8+/-5.7%, P=0.06), no significant change in the 10-microg bFGF group, and significant improvement in the 100-microg bFGF group (19.2+/-5.0% to 9.1+/-5.9%, P=0.01). Magnetic resonance assessment of the target ischemic zone in a subset of patients showed a trend toward a reduction in the target ischemic area in the 100-microg bFGF group (10.7+/-3.9% to 3. 7+/-6.3%, P=0.06). CONCLUSIONS: This study of bFGF in patients undergoing CABG demonstrates the safety and feasibility of this mode of therapy in patients with viable myocardium that cannot be adequately revascularized.

Phase I trial to determine the safety, pharmacodynamics, and pharmacokinetics of RSR13, a novel radioenhancer, in newly diagnosed glioblastoma multiforme.

PURPOSE: To determine the safety, pharmacokinetics, and pharmacodynamic effect of 2-[4-(3, 5-dimethylanilino)carbonyl]methyl]phenoxy]-2-methylproprionic++ + acid (RSR13) 100 mg/kg/d with radiation therapy (RT) for glioblastoma multiforme (GBM). RSR13, a synthetic allosteric modifier of hemoglobin (HgB), is a novel radioenhancing agent that noncovalently binds to HgB, thereby reducing oxygen binding affinity and increasing tissue oxygen release to hypoxic tissues. PATIENTS AND METHODS: In this multi-institutional, dose frequency-seeking trial, 19 adult patients with newly diagnosed GBM received RSR13 100 mg/kg every other day or daily along with cranial RT (60 Gy/30 fractions). RSR13 was given over 1 hour by central venous access with 4 L/min of O(2 )by nasal cannula, followed by RT within 30 minutes. Pharmacokinetic (PK) and pharmacodynamic (PD) determinations were performed. The PD end point was shift in P50, the oxygen half-saturation pressure of HgB. RESULTS: Grade 3 dose-limiting toxicity occurred in none of the patients with every-other-day dosing and in two of the 10 patients with daily dosing. Grade 2 or greater toxicity occurred in three out of nine and six out of 10, respectively. PK and PD data demonstrate that a substantial PD effect was reliably achieved, that PD effect was related to RBC RSR13 concentration, and that there was no significant drug accumulation even with daily dosing. The mean shift in P50 was 9.24 +/- 2.6 mmHg (a 34% increase from baseline), which indicates a substantial increase in tendency toward oxygen unloading. CONCLUSION: Daily RSR13 (100 mg/kg) during cranial RT is well tolerated and achieves the desired PD end point. A phase II trial of daily RSR13 for newly diagnosed malignant glioma is currently accruing patients within the New Approaches to Brain Tumor Therapy Central Nervous System Consortium to determine survival outcome.

Survival of patients with newly diagnosed glioblastoma multiforme treated with RSR13 and radiotherapy: results of a phase II new approaches to brain tumor therapy CNS consortium safety and efficacy study.

PURPOSE: The objectives of this phase II study were to determine survival, safety, pharmacokinetics (PK), and pharmacodynamics (PD) of 2,4-[[(3,5-dimethylanilino)carbonyl]methyl]phenoxy]-2-methylpropionic acid (RSR13, efaproxiral) 100 mg/kg per day administered with standard cranial radiotherapy (RT) for the treatment of glioblastoma multiforme (GBM). RSR13, a synthetic allosteric modifier of hemoglobin, is a radiation-enhancing agent that noncovalently binds to hemoglobin, reduces oxygen-binding affinity, and increases oxygen unloading to hypoxic tissue. PATIENTS AND METHODS: Fifty patients with newly diagnosed GBM (Karnofsky performance status >or= 60) were enrolled onto this multicenter phase II study. Patients received daily RSR13 100 mg/kg intravenously infused for 30 minutes immediately before cranial RT (60 Gy in 30 fractions). Supplemental oxygen was given during RSR13 infusion and continued until after the RT treatment was completed. RT was given within 30 minutes of the end of RSR13 infusion. PK and PD determinations were performed. RESULTS: The median survival for the RSR13-treated patients was 12.3 months with 1-year and 18-month survival rates of 54% and 24%, respectively. Twenty-four percent of patients had greater than grade 2 toxicity, which was generally transient and self-limited. A significant PD effect on hemoglobin-oxygen binding affinity was demonstrated for most patients. CONCLUSION: RSR13 (100 mg/kg) administered immediately before cranial RT is well tolerated and is pharmacodynamically active. Median survival in excess of 1 year is favorable.

Limits of normal left ventricular dimensions in growth and development: analysis of dimensions and variance in the two-dimensional echocardiograms of 268 normal healthy subjects.

The majority of studies generating normal echocardiographic reference values for left ventricular dimensions have been based on blindly performed M-mode measurements, and there are no previous reports based on two-dimensional echocardiography that provide a comprehensive analysis of the two-dimensional measurements from infancy to old age. This report presents the results of analyzing the left ventricular internal dimensions from cross-sectional echocardiographic studies on 268 normal healthy subjects (none were hospitalized for any reason) whose ages ranged from 6 days to 76 years. The mean data are reported as functions of body surface area and, in addition, the variance is modeled as a function of body surface area to provide an accurate and clinically useful determination of normal limits and to model changes in the cardiac dimensions and in their variance representing normal growth and development. The data fit well to the exponential growth model (r values 0.85 to 0.95). Variance about the central values also depended significantly on body size; that relation is represented effectively by a quadratic function of body surface area (r values 0.82 to 0.98). The model parameters allow calculation of normal limits at any desired level of confidence. Areas determined by hand planimetry have significantly greater variance compared with variance of linear dimensions, and also compared with variance of cross-sectional area using ellipses generated from the anteroposterior and mediolateral dimensions. This implies that either biologic variations in the amount of infolding or errors in freehand planimetry constitute a significant source of variance; this may be remedied by filtering out high frequency oscillations of contour. There is no significant difference in midnormal values and confidence limits for corresponding dimensions measured from orthogonal views. Furthermore, the anteroposterior and mediolateral dimensions of the left ventricle superimpose at each body size, consistent with circular cross section for normal subjects throughout growth and development. The data presented should comprise a useful set of reference standards for interpretation of cross-sectional echocardiograms.

Echocardiographic definition of the left ventricular centroid. I. Analysis of methods for centroid calculation from a single tomogram.

Quantitation of myocardial contraction requires a frame of reference. Most investigators have sought a single reference frame per image, centered in some manner with respect to the mass of myocardium. Because there is no anatomic marker for the center of the heart, many different approaches have been pursued to identify a centroid of the left ventricle. The issue of whether the reference should be fixed throughout the cardiac cycle or float from image to image has been addressed in previous studies, but the more fundamental question of how a centroid can best be defined has not been answered. This study examines this basic issue by analysis of variance from observer to observer, cycle to cycle, animal to animal and method to method. Both endocardial and epicardial borders were digitized twice by each of two observers at 1/30 s intervals spanning the cardiac cycle for each of three cardiac cycles in six normal dogs. The left ventricular centroid was calculated by six methods: center of endocardial coordinates, center of epicardial coordinates, center of mid-myocardial (average) coordinates, center of endocardial area, center of epicardial area and center of mid-myocardial (average) area. The path of each centroid was correlated between observers and correlation coefficients were transformed for analysis of variance. This analysis indicates a best approach to centroid definition through distinct minimization of the variance: the best of the six methods proved to be center of endocardial area.

Echocardiographic definition of the left ventricular centroid. II. Determination of the optimal centroid during systole in normal and infarcted hearts.

Although two-dimensional echocardiography is widely used in both clinical and experimental evaluations of regional cardiac wall motion, there is no established clinical method for quantitative analysis of the wall motion, not even for the normal radial motion observed in short-axis images. Measurement of radial wall motion requires determination of a centroid from which the radii emanate. Depending on its definition, the centroid is variously affected throughout systole by cardiac translation, regional wall motion and any shift of the subject position or transducer. A floating centroid is defined relative to the ventricular walls frame by frame, whereas a fixed centroid never moves with respect to the transducer. Evaluation of the best approach to definition of a centroid was previously presented (part I, this issue). The next question is how to use the centroid. This study examines which of four centroid applications provides the best reference for quantifying regional wall motion during systole. Method 1 is a floating centroid (defined separately for every image frame), method 2 uses the end-diastolic centroid as a fixed reference for all image frames, method 3 uses the end-systolic centroid as a fixed reference and method 4 uses the average as a fixed reference. Wall motion was measured with respect to each of these centroids by determining radial wall motion from end-diastole to end-systole and correlating radial motion throughout the cardiac cycle with that in normal control hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Left atrial dimensions in growth and development: normal limits for two-dimensional echocardiography.

Reference values for normal left atrial dimensions have been based primarily on blind M-mode measurements, with no reports based on two-dimensional echocardiography to provide a comprehensive analysis of the two-dimensional measurements from infancy to old age. This report analyzes the left atrial dimensions from two-dimensional echocardiographic studies in 268 normal healthy subjects to determine normal limits and relations among linear, area and volume measurements of the left atrium. The group mean values change with body size, fitting well to the exponential growth model (r = 0.78 to 0.92). The variance about the mean (which determines normal limits) is represented effectively by a quadratic function of body surface area (r = 0.84 to 0.99). The variables determined by this modeling simplify evaluation of normal limits for any body size at any desired level of confidence, and the data are useful reference standards for interpretation of two-dimensional echocardiograms.

Intracoronary basic fibroblast growth factor (FGF-2) in patients with severe ischemic heart disease: results of a phase I open-label dose escalation study.

OBJECTIVES: Evaluate the safety, tolerability and preliminary efficacy of intracoronary (IC) basic fibroblast growth factor (bFGF, FGF-2). BACKGROUND: FGF-2 is a heparin-binding growth factor capable of inducing functionally significant angiogenesis in animal models of myocardial ischemia. METHODS: Phase I, open-label dose-escalation study of FGF-2 administered as a single 20-min infusion in patients with ischemic heart disease not amenable to treatment with CABG or PTCA. RESULTS: Fifty-two patients enrolled in this study received IC FGF-2 (0.33 to 48 microg/kg). Hypotension was dose-dependent and dose-limiting, with 36 microg/kg being the maximally tolerated dose. Four patients died and four patients had non-Q-wave myocardial infarctions. Laboratory parameters and retinal examinations showed mild and mainly transient changes during the 6-month follow-up. There was an improvement in quality of life as assessed by Seattle Angina Questionnaire and improvement in exercise tolerance as assessed by treadmill exercise testing (510+/-24 s at baseline, 561+/-26 s at day 29 [p = 0.023], 609+/-26 s at day 57 (p < 0.001), and 633+/-24 s at day 180 (p < 0.001), overall p < 0.001). Magnetic resonance (MR) imaging showed increased regional wall thickening (baseline: 34+/-1.7%, day 29: 38.7+/-1.9% [p = 0.006], day 57: 41.4+/-1.9% [p < 0.001], and day 180: 42.0+/-2.3% [p < 0.001], overall p = 0.001) and a reduction in the extent of the ischemic area at all time points compared with baseline. CONCLUSIONS: Intracoronary administration of rFGF-2 appears safe and is well tolerated over a 100-fold dose range (0.33 to 0.36 microk/kg). Preliminary evidence of efficacy is tempered by the open-label uncontrolled design of the study.

VEGF administration in chronic myocardial ischemia in pigs.

OBJECTIVE: Previous investigations have shown the effectiveness of sustained intra- or extravascular administration of vascular endothelial growth factor (VEGF) in chronic myocardial ischemia in improvement of left ventricular function. The present investigations were undertaken in order to evaluate efficacy of a single bolus or local intracoronary delivery. METHODS: Yorkshire pigs underwent placement of a left circumflex artery ameroid occluder. Three weeks later the animals were randomized to treatment with VEGF (20 micrograms) accomplished by local intracoronary delivery system (InfusaSleeve, n = 10), intracoronary bolus infusion (n = 7) or by epicardial implantation of an osmotic delivery system (n = 7). An additional group of animals received intracoronary administration of saline and served as a control (n = 9). Three weeks after initiation of therapy, the animals were evaluated with regard to myocardial perfusion and global as well as regional ventricular function. RESULTS: All three VEGF treatment groups but not the control animals demonstrated a significant increase in the left-to-left (but not right-to-left) collateral index, myocardial blood flow (pre-therapy LCX vs. LAD (average of all groups): 0.76 +/- 0.35 vs. 0.96 +/- 0.38 ml*min-1*g-1, p = 0.03; post-therapy: LCX vs. LAD: 1.16 +/- 0.39 vs. 1.15 +/- 0.28 ml*min-1*g-1, p = NS) and coronary vasodilatory reserve 3 weeks after growth factor administration. The observed increase in VEGF-induced perfusion correlated with improvement in regional ventricular function in all VEGF-treated groups (pre-therapy vs. post-therapy: i.c. VEGF 20 +/- 5.1 vs. 33 +/- 4.8; local VEGF 16 +/- 2.8 vs. 33.6; pump VEGF 17 +/- 3.8 vs. 34 +/- 4.9 p < 0.05 for all) but not control animals (21 +/- 3.3 vs. 27 +/- 5.8, p = NS). CONCLUSION: Single intracoronary delivery (intravascular bolus or local delivery) of VEGF is effective in stimulating physiologically significant angiogenesis in porcine model of chronic myocardial ischemia.

Sensitivity of human glioma U-373MG cells to radiation and the protein kinase C inhibitor, calphostin C.

We assessed the radiosensitivity of the grade III human glioma cell line U-373MG by investigating the effects of radiation and the specific protein kinase C inhibitor, calphostin C on the cell cycle and cell proliferation. Irradiated glioma U-373MG cells progressed through G1-S and underwent an arrest in G2-M phase. The radiosensitivity of U-373MG cells to graded doses of either photons or electrons was determine by microculture tetrazolium assay. The data was fitted to the linear-quadratic model. The proliferation curves demonstrated that U-373MG cells appear to be highly radiation resistant since 8 Gy was required to achieve 50% cell mortality. Compared to radiation alone, exposure to calphostin C (250 nM) 1 h prior to radiation decreased the proliferation of U-373MG by 76% and calphostin C provoked a weakly synergistic effect in concert with radiation. Depending on the time of application following radiation, calphostin C produced an additive or less than additive effect on cell proliferation. We postulate that the enhanced radiosensitivity observed when cells are exposed to calphostin C prior to radiation may be due to direct or indirect inhibition of protein kinase C isozymes required for cell cycle progression.

Accumulation of fluoxetine and norfluoxetine in human brain during therapeutic administration.

In vivo 19fluorine nuclear magnetic resonance spectroscopy was used to measure the brain concentration of fluoxetine and norfluoxetine in five patients with obsessive-compulsive disorder and three with major depression. The mean brain:plasma ratio of the parent drug plus the metabolite was significantly elevated to 2.6 (SD = 1.0) (95% confidence interval = 1.9-3.3). This accumulation may have implications for understanding both the therapeutic and the toxic effects of fluoxetine.

Troponin T is capable of binding dystrophin via a leucine zipper.

Using genetic and physical assays for protein-protein interactions, we identified a fast isoform of troponin T that binds to dystrophin. Troponin T specifically bound to the first of two highly conserved leucine zipper motifs in the carboxy terminus of dystrophin [1,2]. Single amino acid changes in the zipper predicted to disrupt alpha-helix formation or cause steric hindrance abolished this binding. These data support the hypothesis that dystrophin couples the contractile apparatus to the sarcolemma and indicate that leucine zipper mediated protein-protein interactions are functionally important in the cytoskeleton as well as the nucleus.

Heterogeneity of guanylyl cyclase C expressed by human colorectal cancer cell lines in vitro.

In humans, guanylyl cyclase C (GCC) is expressed by mucosal cells lining the intestine, from the duodenum to the rectum, but not by extraintestinal tissues. Expression of GCC persists after mucosal cells undergo neoplastic transformation, and this protein has been identified in all primary and metastatic colorectal tumors examined to date, suggesting that GCC may be a highly specific biomarker for colorectal cancer. The utility of GCC as a diagnostic biomarker and therapeutic target is predicated, in part, on defining the variability of its expression in colorectal cancer cells. Similarly, the utility of this biomarker to define tumor burden in diagnosing, staging, and postoperative surveillance of patients is predicated on quantifying GCC expression in cancer cells in tissues and blood. The present studies examined the heterogeneity of GCC expression in eight human colorectal carcinoma cell lines in vitro representing the full spectrum of cytological differentiation. Quantification of GCC expression by ligand binding and stimulation of cGMP accumulation demonstrated that functional GCC expression is heterogeneous in different colorectal cancer cell lines. Qualitative reverse transcription (RT)-PCR demonstrated that all colorectal cancer cells examined expressed GCC mRNA. However, GCC expression varied 100-fold in different colorectal cancer cell lines, determined by a novel quantitative RT-PCR assay. Functional and molecular expressions of GCC were unrelated to the differentiation state of cancer cells. These studies suggest that GCC is heterogeneously expressed by colorectal cancer cells in vitro and suggest a role for quantitative RT-PCR analysis in the development of diagnostic tests using GCC as a biomarker for metastatic colorectal cancer.

Chagas' disease in northern California. No longer an endemic diagnosis.

Chagas' disease has long been considered a diagnosis endemic to South and Central America, with over 10 million seropositive cases in Brazil alone, and over 25 percent of infants in rural Brazil with demonstrable parasitemia. In northern California, progressive biventricular heart failure developed in a 75-year-old woman with a history of right bundle branch block, sinus bradycardia, and ventricular dysrhythmias. Echocardiography showed a characteristic pattern of inferoposterior hypokinesis with relatively intact septal motion. Complement fixation titers for Trypanosoma cruzi were diagnostic. The chronic forms of Chagas' disease may not be manifest until 30 years after the insect bite. It is this factor of prolonged latency, in relation to modern migration and relocations, that makes Chagas' disease no longer an endemic diagnosis.

Development of a head and neck companion module for the quality of life-radiation therapy instrument (QOL-RTI)

PURPOSE/OBJECTIVE: A review of available head and neck quality of life (QOL) instruments reveals them to inadequately address important radiation related side effects, or to be too cumbersome for routine use. The purpose of this study was to develop a head and neck disease specific module as a companion to the previously developed quality of life - radiation therapy instrument (QOL-RTI). The goal was to create a more complete, yet concise, head and neck site-specific module geared toward patients receiving radiation therapy for head and neck cancer. METHODS AND MATERIALS: This exploratory study included 34 consecutive patients undergoing definitive radiotherapy over a 6-7 week course (60-79.8 Gy). We developed and administered a 14-item questionnaire to all eligible patients treated with radiotherapy for head and neck cancer who were not already registered in another research study assessing quality of life (e.g., RTOG). During the treatment period, the QOL-RTI general tool and the head and neck (H&N) module were administered as follows: at baseline, at week four (for test-retest), and at the end of the treatment period. For validation purposes the QOL-RTI/H&N was compared to the functional assessment cancer tool head and neck (FACT-H&N) questionnaire. The FACT-H&N was administered one time at week 4, on the same day as the QOL-RTI/H&N. This report includes the treatment phase of the study (during the course of radiation). RESULTS: Mean age was 62 years (range 40-75). Internal consistency of the module was satisfactory (Chronbach's alpha = 0.85). Test-retest yielded a correlation coefficient of 0.90 (p < 0.001). Concurrent validity, established by comparing the module to the FACT/H&N , yielded a correlation coefficient of 0.85. Significant changes in quality of life scores during a course of radiation was noted for both general quality of life tool and the site specific module. For the head and neck module, the difference in the mean baseline (7.17) and end of treatment scores (4.20) was 2.94, or 42% change (p < 0.0001). A smaller, yet still significant, difference in scores was seen in the general QOL tool (22 % change, p = 0.001). Item analysis of the module revealed statistically significant (p < 0.05) worsening in quality of life scores in the following areas: pain in throat, swallowing difficulty (meat/bread and liquids), changes in mucous and saliva, changes in taste, difficulty chewing, trouble with coughing, and speech difficulties. Items that were not significant were pain in the mouth, and appearance. CONCLUSION: These initial results suggest that the H&N companion module to the QOL-RTI is a valid and reliable tool that is responsive to changes in QOL during a course of H&N radiation therapy. This tool differs from existing H&N tools by including specific assessments of mucous, saliva, taste, cough, and local pain in a concise format. Significant changes in QOL scores were noted in all of these items. Evaluation of the tool in the post-treatment period (follow-up) is ongoing.

A new method of culturing and transferring iris pigment epithelium.

PURPOSE: To optimize a culture technique and transfer iris pigment epithelial (IPE) cells for cellular studies in vitro. METHODS: Porcine iris tissues were obtained, and IPE cells were isolated and cultured at high densities by plating them in the form of drops. Spherically shaped structures containing a high concentration of cells were formed after 7 to 10 days of culture. Cells were subcultured by transferring spheres to new culture dishes without employing enzymatic dissociation. The purity of IPE cells was determined by pigmentation and cytokeratin labeling. Proliferation was assessed by incorporation of 5-bromo-2'-deoxyuridine. Cellular structure was analyzed under the light and electron microscopes and function was assayed by rod outer segment phagocytosis. RESULTS: Iris pigment epithelial cells, when cultured at high densities, tended to form elevated spherical structures containing viable cells. The cultured cells were pigmented and showed positive labeling with a monoclonal cytokeratin antibody. The IPE cells proliferated and migrated from the spheres to form monolayers. Cells originating from the transferred spheres also continued to proliferate and to migrate in a similar manner to the originally cultivated cells to form monolayers after 7 to 10 days. These cells were able to phagocytose rod outer segments. CONCLUSIONS: This new method provides a simple method of culturing a large quantity of IPE cells. The high yield of pure IPE cells and the ease of transfer provide an ideal means to study them at the cellular level.

Diagnostic value for coronary artery disease of chest pain during dipyridamole-thallium stress testing.

Intravenous dipyridamole with thallium imaging permits stress testing for coronary artery disease (CAD) without exercise. Chest pain may occur with dipyridamole-thallium testing, but its diagnostic significance is uncertain. Forty-five patients who had coronary angiography, no revascularization and chest pain during dipyridamole-thallium testing were identified. These patients were matched blindly by sex and age to 45 patients who had coronary angiography, no revascularization and no chest pain reported during the dipyridamole-thallium test. In the groups with versus without chest pain, 9 versus 24% had no CAD, 16 versus 16% had 1-vessel disease, 38 versus 29% had 2-vessel CAD and 38 versus 29% had 3-vessel CAD. These differences did not achieve statistical significance. Also, there were no evident differences in the severity of angiographic CAD by vessel or by percent of stenosis (p greater than 0.50). There was only a moderate association with ischemic ST changes (40 versus 16%, p less than 0.02). Chest pain with concurrent ischemic ST changes also failed to predict any difference in distribution or severity of angiographic stenoses. We conclude that chest pain during dipyridamole-thallium testing is not closely related to the severity of CAD and has little diagnostic value.