Cardiac Magnetic Resonance Reveals Incipient Cardiomyopathy Traits in Adult Patients With Phenylketonuria.

Background Phenylketonuria is the most common inborn error of amino acid metabolism, where oxidative stress and collateral metabolic abnormalities are likely to cause cardiac structural and functional modifications. We aim herein to characterize the cardiac phenotype of adult subjects with phenylketonuria using advanced cardiac imaging. Methods and Results Thirty-nine adult patients with phenylketonuria (age, 30.5±8.7 years; 10-year mean phenylalanine concentration, 924±330 µmol/L) and 39 age- and sex-matched healthy controls were investigated. Participants underwent a comprehensive cardiac magnetic resonance and echocardiography examination. Ten-year mean plasma levels of phenylalanine and tyrosine were used to quantify disease activity and adherence to treatment. Patients with phenylketonuria had thinner left ventricular walls (septal end-diastolic thickness, 7.0±17 versus 8.8±1.7 mm [P<0.001]; lateral thickness, 6.1±1.4 versus 6.8±1.2 mm [P=0.004]), more dilated left ventricular cavity (end-diastolic volume, 87±14 versus 80±14 mL/m2 [P=0.0178]; end-systolic volume, 36±9 versus 29±8 mL/m2 [P<0.001]), lower ejection fraction (59±6% versus 64±6% [P<0.001]), reduced systolic deformation (global circumferential strain, -29.9±4.2 % versus -32.2±5.0 % [P=0.027]), and lower left ventricular mass (38.2±7.9 versus 47.8±11.0 g/m2 [P<0.001]). T1 native values were decreased (936±53 versus 996±26 ms [P<0.001]), with particular low values in patients with phenylalanine >1200 µmol/L (909±48 ms). Both mean phenylalanine (P=0.013) and tyrosine (P=0.035) levels were independently correlated with T1; and in a multiple regression model, higher phenylalanine levels and higher left ventricular mass associate with lower T1. Conclusions Cardiac phenotype of adult patients with phenylketonuria reveals some traits of an early-stage cardiomyopathy. Regular cardiology follow-up, tighter therapeutic control, and prophylaxis of cardiovascular risk factors, in particular dyslipidemia, are recommended.

Potential reduction of interstitial myocardial fibrosis with renal denervation.

BACKGROUND: Hypertensive cardiomyopathy is characterized by myocyte hypertrophy and interstitial fibrosis. The effects of renal denervation (RD) on the heart are poorly understood. New magnetic resonance imaging techniques (extracellular volume fraction) permit the quantitative assessment of myocardial fibrosis. Our aim was to study the effects of RD on myocardial fibrosis. METHODS AND RESULTS: Twenty­three patients with resistant hypertension undergoing RD and 5 resistant hypertensive controls were prospectively included. Cardiac magnetic resonance imaging at 1.5 T was performed before RD and at 6­month follow­up. Indexed left ventricular mass, septal extracellular volume fraction, and indexed absolute extracellular volume (a quantitative measure of extracellular matrix) were quantified. All data are reported as mean±SD deviation (median). Decreases in systolic (161.96±19.09 [160] versus 144.78±16.48 [143] mm Hg, P<0.0001) and diastolic (85.61±12.88 [83] versus 80.39±11.93 [81] mm Hg, P=0.018) blood pressures and in indexed left ventricular mass (41.83±10.20 [41.59] versus 37.72±7.44 [38.49] g/m1.7, P=0.001) were observed at follow­up only in RD patients. No significant differences in extracellular volume were found (26.24±3.92% [26.06%] versus 25.74±4.53% [25.63%], P=0.605). A significant decrease in absolute extracellular volume was observed after 6 months in RD patients exclusively (10.36±2.25 [10.79] versus 9.25±2.38 [9.79] mL/m1.7, P=0.031). This effect was observed independently of blood pressure reduction. CONCLUSIONS: RD significantly decreases left ventricular mass, while extracellular volume remains stable. Our results suggest that the observed left ventricular mass decrease was due not exclusively to a reversion of myocyte hypertrophy but also to an additional reduction in collagen content, indicating interstitial myocardial fibrosis.

CD40/CD40L interaction induces E-selectin dependent leukocyte adhesion to human endothelial cells and inhibits endothelial cell migration.

BACKGROUND: CD40 is a receptor expressed on a wide range of cells such as leukocytes and endothelial cells (EC). As a member of the tumor necrosis factor (TNF) superfamily the activation of CD40 by CD40-ligand (CD40L) plays a crucial role for the development and progression of a variety of inflammatory processes including atherosclerosis. The aim of the present study was to investigate the effect of CD40/CD40L interaction on leukocyte adhesion to the endothelium and on endothelial cell migration. METHODS AND RESULTS: Human umbilical vein endothelial cells (HUVEC) were stimulated with either stable transfectants of mouse myeloma cells expressing the CD40L or wild type cells (4 h). Subsequently adhesion of leukocytes expressing Sialyl Lewis X, the counterpart for E-selectin (HL60 cells), was measured under shear stress (2-2.6 dyne/cm(2)) using a flow chamber adhesion assay. Stimulation of CD40 led to a significant increase of E-selectin dependent adhesion of leukocytes to the endothelium. Incubation of cells with either the CD40L blocking antibody TRAP-1 or the E-selectin blocking antibody BBA2 during CD40 stimulation completely abolished adhesion of leukocytes to HUVEC. Similar results were found in human cardiac microvasculature endothelial cells (HCMEC). In contrast stimulation of CD40 had no effect on adhesion of L-selectin expressing NALM6-L cells. Furthermore, CD40/CD40L interaction abrogated VEGF-induced migration of HUVEC compared to non-stimulated controls. In comparison experiments, stimulation of endothelial cells with VEGF led to a significant phosphorylation of ERK1/2, Akt, and eNOS. Stimulation of endothelial CD40 had no effect on VEGF-induced phosphorylation of ERK1/2. However, VEGF-induced activation of Akt and eNOS was reduced to baseline levels when endothelial CD40 was stimulated. CONCLUSION: CD40/CD40L interaction induces E-selectin dependent adhesion of leukocytes to human endothelial cells and reduces endothelial cell migration by inhibiting the Akt/eNOS signaling pathway.

Chronic CRP-exposure inhibits VEGF-induced endothelial cell migration.

UNLABELLED: C-reactive protein (CRP) is a pluripotent mediator of inflammation and is present at sites of vascular injury and in atherosclerotic lesions. CRP stimulates endothelial cell adhesion molecule expression and monocyte migration, thereby contributing to the development and progression of vascular lesion formation. In addition, chronic exposure to CRP is known to inhibit angiogenesis and endothelial cell (EC) proliferation. AIM: Whether CRP also affects EC migration, however, has yet to be determined. The present study investigates how long-term exposure to CRP interacts with vascular endothelial growth factor (VEGF) -induced EC migration. METHODS AND RESULTS: Using a Transwell chamber migration assay, VEGF (20 ng/mL, 5 h incubation)-induced migration of human umbilical vein EC was significantly inhibited in cells pretreated with CRP (10 microg/mL) for 24 h by more than 75%. EC migration in response to VEGF is known to require activation of the protein kinase B (Akt)/endothelial NO synthase (eNOS)- and the extracellular signal-regulated protein kinase 1/2 (ERK1/2) pathway. We therefore investigated the long-term effects of CRP on these signalling events. Immunoblotting with phosphospecific antibodies revealed rapid and transient activation/phosphorylation of the protein kinase Akt within 20 minutes after stimulation with VEGF, which was inhibited by 86% in EC pretreated with CRP (10 microg/mL, 24 h, p<0.05). Subsequent VEGF-induced phosphorylation of eNOS downstream of Akt was completely inhibited in CRP-treated EC. In contrast, CRP-pretreatment did not affect VEGF-induced phosphorylation of ERK1/2. Interestingly, stimulation of EC with CRP for 16-24 h induced marked expression of the phosphatase and tensin homolog (PTEN), which functions as a negative regulator of phosphatidylinositol 3 kinase (PI3K) -->Akt signalling. CONCLUSION: The observed time course for CRP-mediated PTEN upregulation corresponds to the exposure time needed for inhibition of Akt phosphorylation and migration and may therefore constitute a potential mechanism by which CRP inhibits inducible Akt phosphorylation and EC migration.

High resolution magnetic resonance imaging in atherosclerotic mice treated with ezetimibe.

High field magnetic resonance imaging (MRI) was performed to investigate the long-term effect of ezetimibe (eze), a cholesterol resorption blocker, on atherosclerotic lesion formation in the thoracic aorta of apolipoprotein E-deficient mice (apoE ( -/- )) in comparison to wild type mice (WT). Fifteen-month-old apoE ( -/- ) (Western type diet), apoE ( -/-eze ) (Western type diet with eze) which received eze (5 mc/kg/day) continuously, and age-matched WT (normal chow) were studied using contrast-enhanced 3D turbo-spin-echo sequences (RARE factor 2) on a 7 Tesla scanner. Vessel parameters were analyzed in the aortic root (AR) and aortic arch (AA) and compared to those found in histology. Plasma cholesterol levels were reduced at 15 months by 71% (P < 0.01) in apoE ( -/-eze ) compared to apoE ( -/- ). Vessel wall thickness was increased in the AR and AA in apoE ( -/- ) by 189.1 and 147.2%, respectively compared to WT. ApoE ( -/-eze ) showed reduced wall thickness in the AR (127.4%) and AA (102.8%, both P < 0.05 vs. apoE ( -/- )). A significant increase in total aortic vessel area was determined in the AR and AA in apoE ( -/- ) by 134.7 and 118.3%, respectively, compared to WT. This effect was inhibited in apoE ( -/-eze ) (AR: 126.7%, AA: 86.4%, both P < 0.05). Histological analysis confirmed the effect of eze observed by MRI and demonstrated a significant correlation between the two techniques (P < 0.001). MRI demonstrates that ezetimibe significantly reduces atherosclerotic disease in apoE ( -/- ). MRI is therefore a useful technique to perform in vivo interventional studies in experimental atherosclerosis.

Anterior cruciate ligament reconstruction with Achilles tendon allografts in revisions and in patients older than 30.

We evaluated the results of anterior cruciate ligament (ACL) reconstruction using an Achilles tendon allograft in revisions and in patients older than 30. Results from 23 consecutive patients (mean age, 43 years) who underwent ACL reconstruction with fresh-frozen, irradiated (22/23) Achilles allografts were retrospectively reviewed. Seven cases were revisions. Patients were evaluated with physical examination, questionnaires, and x-rays. Twenty of the 23 patients were evaluated a mean of 28 months after surgery. There were 5 failures (21%); 3 acute failures were not evaluated at follow-up. One patient had an infection that required graft removal, 2 patients had mechanical failure of the grafts, and 2 had displacements of more than 5.5 mm as measured with a KT-1000 arthrometer. The 18 clinically successful cases had full motion, no thigh atrophy, and no effusion. Pivot shift scores were 55% A and 45% B on the International Knee Documentation Committee (IKDC) scale. Lachman scores were 40% A, 55% B, and 5% C on the IKDC scale. The KT-1000 difference was a mean of 2.9 mm at final follow-up. However, knees loosened a mean of 4.5 mm from the immediate postoperative measurements (P<.0001). Mean Lysholm and Tegner scores were 86.8 and 5.2, respectively. Tibial tunnel diameter increased by 3.1 mm on anteroposterior x-rays and 3.0 mm on lateral x-rays. Five patients developed mild medial compartment arthritis. Four of the 5 grafts with failures were from donors older than 40. Postoperative complications included deep vein thrombosis and inflammatory effusion (white blood cell count, 15,000). Twenty-one percent of ACL reconstructions with Achilles tendon allografts failed. Grafts deemed successful still had significant loosening at final follow-up. Allografts from donors older than 40 may have played a role in these failures. From the data in this study, it appears that surgeons should scrutinize the source of the allograft tissue and the age of the donor.

Monitoring therapeutical intervention with ezetimibe using targeted near-infrared fluorescence imaging in experimental atherosclerosis.

Ezetimibe (EZE), an inhibitor of cholesterol absorption, reduces atherosclerosis in apolipoprotein E-deficient (apoE(-/-)) mice. The matrix protein ED-B fibronectin (ED-B) is upregulated in atherosclerotic lesions. Using a novel conjugate for near-infrared fluorescence (NIRF) imaging targeting ED-B, we studied the effect of EZE on plaque lesion formation in apoE(-/-) mice. ApoE(-/-) mice received EZE (5 mug/kg/d) or chow up to the age of 4, 6, and 8 months. NIRF imaging of aortic lesions was performed 24 hours after intravenous application ex vivo and in vivo. Plaque lesion formation was analyzed by histology and immunohistochemistry. Aortic lesion formation detected by Sudan staining and NIRF imaging was significantly reduced at 6 and 8 months (p < .001). Plaque areas determined by NIRF imaging significantly correlated with Sudan staining (p < .001). EZE treatment resulted in a significant reduction in plaque macrophage and ED-B immunoreactivity (both p < .05) in brachiocephalic lesions. There was a significant reduction in plaque size in brachiocephalic arteries in 8-month-old mice treated with EZE compared with mice during short-term treatment (p < .05), indicating EZE plaque regression. Targeted NIRF imaging showed a correlation to histologic lesion extension during therapeutical intervention in experimental atherosclerosis.

In vivo imaging of the inflammatory receptor CD40 after cerebral ischemia using a fluorescent antibody.

BACKGROUND AND PURPOSE: Brain inflammation is a hallmark of stroke, where it has been implicated in tissue damage as well as in repair. Imaging technologies that specifically visualize these processes are highly desirable. In this study, we explored whether the inflammatory receptor CD40 can be noninvasively and specifically visualized in mice after cerebral ischemia using a fluorescent monoclonal antibody, which we labeled with the near-infrared fluorescence dye Cy5.5 (Cy5.5-CD40MAb). METHODS: Wild-type and CD40-deficient mice were subjected to transient middle cerebral artery occlusion. Mice were either intravenously injected with Cy5.5-CD40MAb or control Cy5.5-IgGMAb. Noninvasive and ex vivo near-infrared fluorescence imaging was performed after injection of the compounds. Probe distribution and specificity was further assessed with single-plane illumination microscopy, immunohistochemistry, and confocal microscopy. RESULTS: Significantly higher fluorescence intensities over the stroke-affected hemisphere, compared to the contralateral side, were only detected noninvasively in wild-type mice that received Cy5.5-CD40MAb, but not in CD40-deficient mice injected with Cy5.5-CD40MAb or in wild-type mice that were injected with Cy5.5-IgGMAb. Ex vivo near-infrared fluorescence showed an intense fluorescence within the ischemic territory only in wild-type mice injected with Cy5.5-CD40MAb. In the brains of these mice, single-plane illumination microscopy demonstrated vascular and parenchymal distribution, and confocal microscopy revealed a partial colocalization of parenchymal fluorescence from the injected Cy5.5-CD40MAb with activated microglia and blood-derived cells in the ischemic region. CONCLUSIONS: The study demonstrates that a CD40-targeted fluorescent antibody enables specific noninvasive detection of the inflammatory receptor CD40 after cerebral ischemia using optical techniques.

Cardiovascular diseases as target for imaging.

Recent pathophysiological findings have lead to new concepts to identify patients at risk for cardiovascular disease using systemic serum markers or new imaging methodology. New probe technology and progress in imaging techniques have set the base for development of molecular imaging concepts in the cardiovascular systems. The aim of these new imaging techniques is the detection of active biological processes in cardiovascular systems combining specific probes with contrast agents for MRI, SPECT or PET. There are promising strategies mostly in preclinical tests, which will prove clinical applicability in the near future.

ED-B fibronectin (ED-B) can be targeted using a novel single chain antibody conjugate and is associated with macrophage accumulation in atherosclerotic lesions.

It has been shown that ED-B fibronectin (ED-B) is a potential target for plaque imaging. The aim of this study was to test a novel modified single chain anti-ED-B antibody (scFv) conjugated for near infrared fluorescence imaging (NIRF) with tetrasulfonated carbocyanine-maleimide (TSC-scFv) and to examine the association of ED-B with the presence of macrophages in a murine model of atherosclerosis. Expression of ED-B was observed in plaque areas in apolipoprotein E-deficient (apoE(-/-)) mice which increased with age and plaque load. Robust imaging was possible after explantation of the aorta and demonstrated a strong NIRF signal intensity in focal aortic and brachiocephalic plaque lesions, whereas no signals were found in undiseased areas. Plaque lesion ED-B was expressed by smooth muscle cell and was closely associated to macrophage infiltrates. Although not expressed by the same cell type, there was a significant correlation (p<0.01) between ED-B and macrophage immunoreactivity. In vitro human coronary and mouse smooth muscle cells significantly increased ED-B expression after angiotensin II and TNF-alpha treatment. This study demonstrates that plaque NIRF imaging is feasible with a novel single chain antibody and that ED-B expression is closely associated with inflammation in experimental atherosclerosis.

Mucormycosis of the upper extremity in a patient with alcoholic encephalopathy.

UNLABELLED: Cutaneous mucormycosis is a rare opportunistic infection caused by fungi of the class Zygomycetes that can be rapidly fatal if unrecognized. The diagnosis of this infection is often made by infectious disease, dermatologic, or intensive care specialists. Lesions that affect the upper limb may require a hand surgeon to diagnose the infection. The diagnosis may be difficult to make, because these infectious lesions can be confused with ischemic pathology. We report on a rare case of cutaneous mucormycosis caused by Rhizopus arrhizus in a patient with cirrhosis and renal failure who presented with an ischemic hand. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic V.

A device for zone-II flexor tendon repair. Surgical technique.

BACKGROUND: The stainless-steel Teno Fix tendon-repair device has improved biomechanical characteristics compared with those of suture repair, and it was well tolerated in a canine model. The purpose of this study was to compare the Teno Fix with suture repair in a clinical setting. METHODS: Sixty-seven patients with isolated zone-II flexor tendon injury were randomized to be treated with a Teno Fix or a four-stranded cruciate suture repair. There were eighty-five injured digits: thirty-four were treated with the Teno Fix, and fifty-one served as controls. A modified leinert rehabilitation technique was employed, with active flexion starting at four weeks postoperatively. Patients were followed for six months by blinded observers who determined the range of motion, Disabilities of the Arm, Shoulder and Hand (DASH) score, pinch and grip strength, and pain score on a verbal scale and assessed swelling and neurologic recovery. Adverse outcomes, including device migration and rupture, were monitored at frequent intervals. RESULTS: Nine of the fifty-one suture repairs ruptured, whereas none of the Teno Fix repairs ruptured (p < 0.01). Five of the nine ruptures were caused by resistive motion against medical advice. There were no differences between the two groups in terms of range of motion, DASH score, pinch and grip strength, pain, swelling, or neurologic recovery. The Teno Fix group had slightly slower resolution of pain and swelling compared with the control group. Of the patients who were available for follow-up at six months, sixteen of the twenty-four treated with a Teno Fix repair and nineteen of the twenty-seven treated with a control repair had a good or excellent result. One Teno Fix device migrated and extruded secondary to a wound infection. Of all eighty-five digits that were operated on, four were thought to have tendons of inadequate size to accommodate the device and nine were deemed to have inadequate exposure to allow placement of the anchors. CONCLUSIONS: The Teno Fix is safe and effective for flexor tendon repair if the tendon size and exposure are sufficient. Tendon repairs with the Teno Fix have lower rupture rates and similar functional outcomes when compared with conventional repair, particularly in patients who are non-compliant with the rehabilitation protocol.

Binding of human serum amyloid P componentto L-selectin.

Serum concentrations of soluble L-selectin by far exceed those of other soluble adhesion molecules, and serum soluble L-selectin concentrations are remarkably stable upon prolonged storage. We present evidence for Ca(2+)-dependent binding interactions between human serum amyloid P (SAP), a proteolysis-resistant pentraxin glycoprotein, and L-selectin, as shown by surface plasmon resonance measurements, protein band shift assays in a native PAGE system, and after SDS-PAGE and membrane transfer. Monoclonal antibodies to L-selectin strongly reduced binding of biotinylated SAP to L-selectin-IgG chimeras immobilized on microtiter plates. As binding was reduced by prior glycopeptidase F treatment of L-selectin but not of SAP, it appears to be based on SAP lectin domain interactions with N-linked L-selectin carbohydrates. In freshly prepared human lymphocytes, SAP incubation induced expression of a beta2 integrin neoepitope associated with high-affinity binding. This was partially blocked by pre-incubation with Fab fragments of two anti-L-selectin antibodies. In flow chamber experiments, SAP inhibited the adherence of human neutrophils to activated endothelium under shear stress. Thus, SAP binds to human L-selectin and affects L-selectin-dependent leukocyte-endothelial interactions.

Wrist denervation and the anterior interosseous nerve: anatomic considerations.

PURPOSE: Wrist denervation via resection of the distal anterior interosseous nerve (AIN) and the posterior interosseous nerve (PIN) is an effective treatment for chronic wrist pain. When performing this procedure through a dorsal approach we have been impressed by anatomic variations of the AIN. This has raised concerns about potential denervation of the pronator quadratus (PQ). The purpose of this study was to elucidate the anatomy of the AIN and PIN as encountered through a dorsal distal forearm incision. METHODS: Ten fresh-frozen cadavers were dissected. Before dissection radiographs were obtained to ensure accurate localization of the proximal ulnar head with a radiopaque marker. A dorsal approach to the distal forearm was made to identify the anatomy of the PIN and AIN. The location and diameter of all AIN branches were noted by using an operating stereoscopic microscope at x 25 magnification and a precision caliper. The PIN anatomy and size also were noted. RESULTS: The anatomy of the AIN was variable. The average AIN diameter proximal to the PQ was 1.5 mm. The average number of AIN motor branches was 4.2. The largest PQ motor branch was the first motor branch and was located at an average distance of 37.9 mm from the proximal ulnar head. The last motor branch was found an average of 23.9 mm from the proximal ulnar head. In 9 of 10 specimens the sensory branch tunneled radially through the distal PQ and innervated the periosteum of the volar distal radius. In 4 of 10 specimens a separate branch to the distal radioulnar joint was present. We found an average PIN diameter of 0.87 mm. CONCLUSIONS: Resection of the AIN at a point 4 cm proximal to the proximal point of the ulnar head would denervate completely the PQ in our cadaver population. Division of the AIN 2 cm proximal to the ulnar head would spare most of the PQ motor branches.

Immunohistochemical localization of subtilisin/kexin-like proprotein convertases in human atherosclerosis.

Integrins are heterodimeric alpha/beta receptors that link the cytoskeleton with the extracellular matrix, thereby regulating several cell functions important in atherosclerosis. In vitro, the subtilisin/kexin-like proprotein convertases (PCs), namely PC5 and furin, have been shown to be responsible for the endoproteolytic activation of the alpha(v) integrin subunit. Based on their cleavage activity, these PCs are potential targets in atherosclerosis. In the present study, we investigated the localization of furin and PC5 in different stages of human atherosclerosis. Immunohistochemical analysis of furin and PC5 revealed their presence in vascular smooth-muscle cells and endothelial cells in atherosclerotic and non-atherosclerotic lesions. However, in the more advanced lesions, furin and PC5 staining was significantly expressed in macrophages/foam cells. In vitro, THP-1 derived macrophages contained furin and PC5, and maturation of monocytes to macrophages was accompanied by enhanced alpha(v)beta3 cell-surface expression. Inhibition of furin/PC5 with the specific pharmacological furin-like PC-inhibitor dec-CMK inhibited alpha(v) endoproteolytic activation but did not abolish alpha(v)beta3 cell-surface expression. This indicates that furin/PC5 is required for alpha(v) endoproteolytic activation but not for alpha(v) routing and sorting to the cell surface. In conclusion, our study demonstrates that furin and PC5 are significantly expressed in mononuclear cells in advanced human atherosclerotic lesions, where they regulate alpha(v) endoproteolytic activation.

Persistent induction of HIF-1alpha and -2alpha in cardiomyocytes and stromal cells of ischemic myocardium.

Hypoxia-inducible factor (HIF)-1alpha and -2alpha are key regulators of the transcriptional response to hypoxia and pivotal in mediating the consequences of many disease states. In the present work, we define their temporo-spatial accumulation after myocardial infarction and systemic hypoxia. Rats were exposed to hypoxia or underwent coronary artery ligation. Immunohistochemistry was used for detection of HIF-1alpha and -2alpha proteins and target genes, and mRNA levels were determined by RNase protection. Marked nuclear accumulation of HIF-1alpha and -2alpha occurred after both systemic hypoxia and coronary ligation in cardiomyocytes as well as interstitial and endothelial cells (EC) without pronounced changes in HIF mRNA levels. While systemic hypoxia led to widespread induction of HIF, expression after coronary occlusion occurred primarily at the border of infarcted tissue. This expression persisted for 4 wk, included infiltrating macrophages, and colocalized with target gene expression. Subsets of cells simultaneously expressed both HIF-alpha subunits, but EC more frequently induced HIF-2alpha. A progressive increase of HIF-2alpha but not HIF-1alpha occurred in areas remote from the infarct, including the interventricular septum. Cardiomyocytes and cardiac stromal cells exhibit a marked potential for a prolonged transcriptional response to ischemia mediated by HIF. The induction of HIF-1alpha and -2alpha appears to be complementary rather than solely redundant.

Magnetic resonance low-dose dobutamine test is superior to SCAR quantification for the prediction of functional recovery.

BACKGROUND: Low-dose dobutamine challenge (DSMR) by MRI was compared with delayed enhancement imaging with Gd-DTPA (SCAR) as a predictor of improvement of wall motion after revascularization (RECOVERY). METHODS AND RESULTS: In 29 patients with coronary artery disease (68+/-7 years of age, 2 women, 32+/-8% ejection fraction), wall motion was evaluated semiquantitatively by MRI before and 3 months after revascularization. SCAR and DSMR were performed before revascularization. The transmural extent of scar was assessed semiquantitatively. Binary prediction of RECOVERY was performed by logistic regression in 288 segments with wall motion abnormalities at rest. Receiver operating characteristic-area under curve (AUC) statistics were used to compare different models. Low-dose DSMR (AUC 0.838) was superior to SCAR (AUC 0.728) in predicting RECOVERY. SCAR did not improve accuracy of prediction by DSMR. Subgroup analysis showed superiority of DSMR for 1% to 74% transmural extent of infarction. CONCLUSIONS: Low-dose DSMR is superior to SCAR in predicting RECOVERY. This advantage is largest in segments with a delayed enhancement of 1% to 74%.

Magnetic resonance imaging in diagnosis of chronic posterolateral rotatory instability of the elbow.

Posterolateral rotatory instability of the elbow can be difficult to diagnose and requires a high degree of clinical suspicion. Cases of chronic posterolateral rotatory instability (symptoms present more than 1 year) may be an even more perplexing subgroup. This is a case report of a patient with a 30-year history of intermittent elbow instability. Clinical examination was equivocal, and magnetic resonance imaging was unable to define any ligamentous injury around the elbow. Examination under anesthesia and surgical findings were consistent with complete disruption of the lateral ulnar collateral ligament. The 12-month follow-up after surgical reconstruction showed complete resolution of symptoms. Posterolateral rotatory instability is a diagnosis largely made by examination under anesthesia. A thorough history and a high clinical suspicion are necessary to support the physician's decision to place the patient under anesthesia. Confirmation of a chronic tear of the lateral ulnar collateral ligament of the elbow with magnetic resonance imaging can be difficult and sometimes misleading.