Chronic relapsing thrombotic thrombocytopenic purpura in adult onset Still's disease.

We report the first known case of chronic relapsing thrombotic thrombocytopenic purpura associated with adult-onset Still's disease. The patient presented with diffuse arthralgias, sore throat, and a maculopapular rash involving the trunk and extremities; she was hospitalized with fever and confusion. Thrombocytopenia, renal failure, and microangiopathic hemolytic anemia developed within several days. After a diagnosis of thrombotic thrombocytopenic purpura was made, she responded well to a series of plasma exchanges. Evaluation for infection, autoimmune disorders, and malignancy was negative. She was discharged to home in good condition, with normal renal function and normal platelet count. Two more episodes of TTP developed 7 and 9 months after the first hospitalization. The diagnosis of adult-onset Still's disease was then determined on the basis of clinical and laboratory criteria. She was successfully treated with plasma exchange, prednisone, and azathioprine. She later had splenectomy and has subsequently been without recurrence of thrombotic thrombocytopenic purpura for 2 years.

Frequency of serum low-density lipoprotein cholesterol measurement and frequency of results < or=100 mg/dl among patients who had coronary events (Northwest VA Network Study).

This population-based, cross-sectional analysis targeted all veterans with coronary heart disease (CHD) who were active patients in primary care or cardiology clinics in the Veterans Health Administration Northwest Network from July 1998 to June 1999. We report guideline compliance rates, including whether low-density lipoprotein (LDL) was measured, and if measured, whether the LDL was < or=100 mg/dl. In addition, we utilized multivariate logistic regression to determine patient characteristics associated with LDL measurements and levels. Of 13,891 active patients with CHD, 5,552 (40.0%) did not have a current LDL measurement. Of those with LDL measurements, 39.1% were at the LDL goal of < or =100 mg/dl, whereas 26.5% had LDL > or =130 mg/dl. Male gender, younger age, history of angioplasty or coronary artery bypass grafting, current hypertension, diabetes mellitus, and angina pectoris were associated with increased likelihood of LDL measurement. Older age and current diabetes and angina were associated with increased likelihood of LDL being < or =100 mg/dl, if measured. Although these rates of guideline adherence in the CHD population compare well to previously published results, they continue to be unacceptably low for optimal clinical outcomes. Attention to both LDL measurement and treatment (if elevated) is warranted.

A mutation in the Lunatic fringe gene suppresses the effects of a Jagged2 mutation on inner hair cell development in the cochlea.

Recent studies have demonstrated that the Notch signaling pathway regulates the differentiation of sensory hair cells in the vertebrate inner ear [1] [2] [3] [4] [5] [6] [7] [8] [9]. We have shown previously that in mice homozygous for a targeted null mutation of the Jagged2 (Jag2) gene, which encodes a Notch ligand, supernumerary hair cells differentiate in the cochlea of the inner ear [7]. Other components of the Notch pathway, including the Lunatic fringe (Lfng) gene, are also expressed during differentiation of the inner ear in mice [6] [7] [8] [9] [10]. In contrast to the Jag2 gene, which is expressed in hair cells, the Lfng gene is expressed in non-sensory supporting cells in the mouse cochlea [10]. Here we demonstrate that a mutation in the Lfng gene partially suppresses the effects of the Jag2 mutation on hair cell development. In mice homozygous for targeted mutations of both Jag2 and Lfng, the generation of supernumerary hair cells in the inner hair cell row is suppressed, while supernumerary hair cells in the outer hair cell rows are unaffected. We also demonstrate that supernumerary hair cells are generated in mice heterozygous for a Notch1 mutation. We suggest a model for the action of the Notch signaling pathway in regulating hair cell differentiation in the cochlear sensory epithelium.

Iliac arteriovenous fistula secondary to iliac aneurysm rupture associated with pulmonary embolism and anuria.

We present a case of iliac aneurysm rupture that started with high-output cardiac failure and anuria and later presented as a pulmonary embolism that needed a preoperatory filter for the cava vein.

Apical plasma membrane proteins and endolyn-78 travel through a subapical compartment in polarized WIF-B hepatocytes.

We studied basolateral-to-apical transcytosis of three classes of apical plasma membrane (PM) proteins in polarized hepatic WIF-B cells and then compared it to the endocytic trafficking of basolaterally recycling membrane proteins. We used antibodies to label the basolateral cohort of proteins at the surface of living cells and then followed their trafficking at 37 degreesC by indirect immunofluorescence. The apical PM proteins aminopeptidase N, 5'nucleotidase, and the polymeric IgA receptor were efficiently transcytosed. Delivery to the apical PM was confirmed by microinjection of secondary antibodies into the bile canalicular-like space and by EM studies. Before acquiring their apical steady-state distribution, the trafficked antibodies accumulated in a subapical compartment, which had a unique tubulovesicular appearance by EM. In contrast, antibodies to the receptors for asialoglycoproteins and mannose-6-phosphate or to the lysosomal membrane protein, lgp120, distributed to endosomes or lysosomes, respectively, without accumulating in the subapical area. However, the route taken by the endosomal/lysosomal protein endolyn-78 partially resembled the transcytotic pathway, since anti-endolyn-78 antibodies were found in a subapical compartment before delivery to lysosomes. Our results suggest that in WIF-B cells, transcytotic molecules pass through a subapical compartment that functions as a second sorting site for a subset of basolaterally endocytosed membrane proteins reaching this compartment.

Localization of integral membrane peptidylglycine alpha-amidating monooxygenase in neuroendocrine cells.

Peptidylglycine alpha-amidating monooxygenase (PAM) catalyzes the amidation of glycine-extended peptides in neuroendocrine cells. At steady state, membrane PAM is accumulated in a perinuclear compartment. We examined the distribution of membrane PAM in stably transfected AtT-20 cells and compared its localization to markers for the trans-Golgi network (TGN), endosomes, and lysosomes. At the light microscopic level, the distribution of membrane PAM does not overlap extensively with lysosomal markers but does overlap with TGN38 and with SCAMP, a component of post-Golgi membranes involved in recycling pathways. By immunoelectron microscopy, membrane PAM is present in tubulovesicular structures which constitute the TGN; some of these PAM-containing tubulovesicular structures are more distal to the Golgi stacks and do not contain TGN38. While some POMC-derived peptides are present in tubulovesicular structures like those that contain membrane PAM, the majority of the POMC-derived peptides are present in secretory granules. There is little overlap between the steady state distribution of membrane PAM and internalized FITC-transferrin in the early endosomes. Few of the perinuclear PAM-containing structures are labeled with HRP or WGA-HRP even following long incubations. Therefore, membrane PAM is localized to perinuclear tubulovesicular structures which are partially devoid of TGN38 and are not all endosomal in origin.

Comparison of myocardial ATP, blood flow, and cytosolic adenosine in demand ischemia and coronary occlusion.

To investigate the relationship between flow and energy metabolism during coronary underperfusion, regional myocardial ATP content, cytosolic adenosine concentrations, and blood flow were measured during segmental coronary artery occlusion (complete ligation, n = 10) and demand ischemia (catecholamines plus atrial pacing with subtotal stenosis, n = 6) in halothane anesthetized open-chest dogs. During coronary occlusion or demand ischemia, L-homocysteine thiolactone was infused for 20 min, after which left ventricular tissue was rapidly frozen and analyzed for regional blood flow (microspheres) and content of ATP and S-adenosylhomocysteine (SAH), an index of cytosolic adenosine. In nonischemic regions, ATP and SAH contents in both groups were the same as in unstimulated control animals with intact coronary circulation (n = 7), indicating that adrenergic stimulation during unrestricted flow had no effect on ATP or cytosolic adenosine. In the ischemic regions of both groups, there were decreases in regional flow, ATP content, and systolic wall thickening, and increases in SAH content. To compare the indexes of energy metabolism in tissue regions receiving equal blood flow, tissue samples were grouped into intervals of equal blood flow (ml.min-1.g-1). At every level of flow, ATP content in demand ischemia was 25-39% higher than in coronary occlusion. Estimates of cytosolic adenosine concentrations (using a mathematical model) in the lowest flow interval averaged 5 microM in demand ischemia, approximately twice as high as in coronary occlusion. It is concluded that in tissue regions receiving equal blood flow, ATP was better maintained and cytosolic adenosine was higher in demand ischemia than in coronary occlusion. The differences in ATP content and cytosolic adenosine were not due to different blood flows but rather to more favorable energy metabolism in demand ischemia.

Comparison of fluorine-18-fluorodeoxyglucose and tritiated fluoromisonidazole uptake during low-flow ischemia.

UNLABELLED: Fluorine-18-fluoromisonidazole (FMISO) is trapped in hypoxic but viable canine myocardium. Because of the potential for its use as a marker of myocardial viability, we compared FMISO activity to [18F]fluorodeoxyglucose (FDG) activity in the same myocardial samples from eight dogs subjected to 3 hr of moderate regional myocardial ischemia. METHODS: Tritiated FMISO was injected 15-30 min after onset of regional ischemia (40%-70% reduction in systolic wall thickening) which was maintained for 3 hr. FDG was injected after 2 hr of ischemia. Myocardial blood flow (MBF) was measured by the radiolabeled microsphere technique at the time of each radiotracer injection. At 3 hr of ischemia, the heart was excised and cut into short-axis slices. One slice encompassing both ischemic and normal tissue was cut into 64 samples. FMISO and FDG activity in each sample were normalized to the mean normal zone activity and further expressed as a function of regional MBF. RESULTS: FMISO uptake was consistently greater than FDG uptake, although this was significantly different only for MBF, between 40%-60% of normal. When analyzed relative to endocardial-epicardial location, endocardial FMISO uptake was significantly greater in all hypoperfused samples. CONCLUSION: These results suggest that FMISO is as sensitive as FDG for detecting myocardial ischemia and could be used for identification of viable myocardium.

Regional myocardial flow and capillary permeability-surface area products are nearly proportional.

Analyses of data on the transcapillary exchange and cellular uptake in the normal heart have generally been based on the assumption that local membrane conductances and volumes of distribution are everywhere the same. The question is whether such an assumption is justified in view of the marked (sixfold) heterogeneity of local blood flows per gram tissue. The method was to estimate both flow and capillary membrane permeability-surface area products (PS) locally in the heart. For each of five dogs running on a sloped treadmill, the deposition of tracer microspheres and of [131I]iodophenylpentadecanoic acid (IPPA), after left atrial injection, was determined in 256 pieces of left ventricular myocardium by killing the animals at approximately 100 s after radiotracer injection. A hydraulic occluder stopped the flow to a portion of the myocardium supplied by the left circumflex coronary artery 30 s before tracer injection. Regional flows ranged from 0.1 to 7.0 ml.g-1.min-1. IPPA extractions ranged from 20 to 49%. Using the known flows, we assumed the applicability of an axially distributed blood-tissue exchange model to estimate the PS for the capillary (PSc) and the parenchymal cell. It was impossible to explain the data if the PSc values for membrane transport were uniform throughout the organ. Rather, the only reasonable descriptors of the data required that local PSc values increase with local flow, almost in proportion. Current methods of analysis using data based on deposition methods need to be revised to take into account the near proportionality of PS to flow for at least some substrates.

Steady-state catecholamine stimulation does not increase cytosolic adenosine in canine hearts.

Myocardial adenosine production increases transiently during the onset of catecholamine stimulation; however, there is conflicting evidence regarding whether cytosolic adenosine concentrations are increased during sustained steady-state stimulation. If cytosolic adenosine is not elevated during steady-state stimulation, then adenosine produced in the cytosol does not play a role in mediating the sustained increase in myocardial blood flow. The purpose of the present study was to determine whether cytosolic adenosine concentrations in the anesthetized dog heart are increased during steady-state stimulation with norepinephrine, epinephrine, and atrial pacing. Regional cytosolic adenosine concentrations were assessed by measuring myocardial content of S-adenosyl-L-homocysteine (SAH) after 20 min of intravenous administration of L-homocysteine thiolactone. Excess homocysteine causes myocardial accumulation of SAH at a rate dependent on the cytosolic concentration of adenosine. Steady-state metabolic stimulation caused more than twofold increases in myocardial blood flow and oxygen consumption, but there was no increase in left ventricular content of SAH in the stimulation group [6.3 +/- 0.9 nmol/g (SE); n = 6] relative to a parallel unstimulated control group (6.4 +/- 0.9 nmol/g; n = 6). The transmural distribution of SAH was nearly uniform, and there was no correlation between regional measurements of blood flow and myocardial content of SAH or ATP either during metabolic stimulation or under control conditions. In separate experiments, myocardial ischemia caused fivefold increases in SAH content, confirming the sensitivity of the SAH method for increased cytosolic adenosine.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of iodovinylmisonidazole as a marker for myocardial hypoxia.

Misonidazole and related compounds are metabolically trapped in viable cells as a function of reduced cellular pO2. [18F]fluoromisonidazole has been used to detect hypoxia in the heart and in tumors noninvasively with positron emission tomography. The purpose of this study was to characterize the uptake of the iodinated misonidazole congener iodovinylmisonidazole (IVM) in ischemic myocardium. In six open chest dogs (Group 1), the left anterior descending (LAD) coronary artery was partially occluded and in four dogs (Group 2), demand ischemia was produced by the combination of atrial pacing and catecholamine infusion in the presence of a LAD stenosis. [131I]IVM (5-15 microCi/kg, i.v.) was given following the onset of ischemia. Tracer deposition was measured by postmortem tissue sampling 4 hr postinjection and compared to microsphere myocardial blood flow (MBF) measurements made at baseline and at 2 hr postinjection. In Group 1, regional IVM deposition in heart samples within the ischemic area was inversely related to MBF with maximum tissue:blood ratios of 3.2. For a given level of reduced blood flow, IVM uptake was higher in the subendocardium indicating a greater vulnerability of the subendocardium to reductions in oxygen delivery. In Group 2, enhanced IVM deposition was detected as a result of demand ischemia, even in some regions where absolute flow was normal or increased from baseline, indicating that flow per se is not the principal determinant of tracer uptake. We conclude that IVM is a promising marker for myocardial hypoxia with potential clinical application using gamma camera imaging.

Noninvasive detection of hypoxic myocardium using fluorine-18-fluoromisonidazole and positron emission tomography.

Fluoromisonidazole (FMISO) is metabolically trapped in viable cells as a function of reduced cellular pO2. Therefore [18F]-FMISO is potentially useful for evaluating patients with hypoxic but viable myocardium. The goal of this study was to investigate [18F]FMISO uptake in ischemic myocardium non-invasively using positron emission tomography (PET). Studies were performed in 10 open-chest dogs subjected to either complete (Group 1, n = 5) or partial (Group 2, n = 5) occlusion of the left anterior descending coronary artery. The tracer was administered by intravenous bolus following the onset of ischemia and serial PET images were acquired for the next 4 hr. In Group 1, viability was assessed using histochemical staining (nitroblue tetrazolium, NBT) and 99mTc-pyrophosphate (Tc-PYP). In Group 2, viability was assessed using measurements of regional wall motion, histochemical staining and histology (two animals). In each study, PET images obtained at times between 2 and 4 hr postinjection showed specific enhancement of tracer activity in the distal anterior wall and apex of the left ventricle. At 4 hr, the tissue-to-blood pool count ratio was significantly higher in ischemic regions; 1.8 +/- 0.4 for Group 1 and 1.6 +/- 0.2 for Group 2 versus 1.0 +/- 0.1 in nonischemic regions. Postmortem tissue sampling of Group 1 hearts showed significant FMISO retention in samples without evidence for infarction, either by NBT or Tc-PYP deposition, as well as in more severely ischemic regions. In Group 2 animals, FMISO was retained in myocardial regions with reduced blood flow (microspheres), which exhibited improved contraction following reperfusion. We conclude that PET imaging of [18F]FMISO is a promising technique for the noninvasive identification of viable hypoxic myocardium.

Synthesis of an (iodovinyl)misonidazole derivative for hypoxia imaging.

Nitroimidazoles undergo a bioreduction in viable hypoxic tissue, resulting in trapping within these tissues, as demonstrated by misonidazole. A radioiodinated analogue of misonidazole (IVM, (E)-5-(2-Nitroimidazolyl)-4-hydroxy-1-iodopent-1-ene, 3) has been synthesized by halodestannylation, for evaluation as an imaging agent for hypoxia. A key step in the synthetic sequence involves the use of the Lewis acid BF3.Et2O to promote the nucleophilic ring opening of glycidyl tosylate with (E)-1-lithio-2-(tributylstannyl)ethylene. Direct comparison of IVM versus F-MISO (2) another misonidazole type hypoxic cell marker, in several in vitro cell culture studies, indicates that IVM behaves in analogous fashion to F-MISO and has promise as a hypoxia imaging agent for SPECT.

Fluoromisonidazole. A metabolic marker of myocyte hypoxia.

Fluoromisonidazole is metabolically trapped in viable hypoxic cells in vitro. This property is the basis for the hypothesis that [18F]fluoromisonidazole can be used to detect hypoxic tissues noninvasively using positron emission tomography. To assess the potential usefulness of this compound as a marker for hypoxic myocardium, we measured the accumulation of [3H]fluoromisonidazole in isolated adult rat myocytes under normoxic, hypoxic (5,000 ppm O2), and anoxic conditions. Both anoxia and hypoxia caused a marked increase in [3H]fluoromisonidazole accumulation. Relative to uptake during normoxia, uptake during anoxia was increased by 8.4-fold at 60 minutes and 26.5-fold at 180 minutes (p less than 0.001). During hypoxia, uptake was increased by 4.4-fold at 60 minutes and by 15.3-fold at 180 minutes (p less than 0.0001) and occurred in the absence of significant cell injury as measured by release of creatine kinase and changes in cell morphology. Additional studies demonstrated a slow oxygen-insensitive efflux of fluoromisonidazole or labeled metabolite(s) from myocytes reincubated in drug-free medium. We conclude that fluoromisonidazole is avidly retained in hypoxic myocytes and thus may be suitable for noninvasive detection of hypoxic myocardium using positron emission tomography.

Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion.

Imaging 123I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 +/- 0.43) was similar to that for microspheres (0.94 +/- 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

Enhanced binding of the hypoxic cell marker [3H]fluoromisonidazole in ischemic myocardium.

The 2-nitroimidazole fluoromisonidazole is metabolically trapped in viable hypoxic cells in inverse proportion to PO2. This attribute suggests that [18F]fluoromisonidazole may be useful for imaging hypoxic tissue using positron emission tomography. To examine this potential, we studied the pharmacokinetics and biodistribution of [3H]fluoromisonidazole in six open chest dogs. In two normal dogs, plasma and urine samples were collected over a 4-hr period following i.v. injection of the drug. In four animals, regional myocardial ischemia was produced 2 hr prior to drug injection by occlusion of the circumflex coronary artery and maintained during the 4-hr sampling period. In all animals, postmortem samples of myocardium and other organs were obtained and tissue, plasma, and urine tritium activity were determined by liquid scintillation counting. In areas of reduced flow, [3H]fluoromisonidazole accumulated in myocardium in inverse proportion to myocardial blood flow measured by microspheres, indicating enhanced binding in hypoxic tissues. Maximum tissue concentrations in ischemic myocardium were two- to three-fold greater than in normal myocardium and plasma. Plasma clearance data indicate the drug is rapidly distributed into the total-body water, clears from the body with a half-life of 275 +/- 50 min, and undergoes minimal metabolism by 4 hr. We conclude [18F]fluoromisonidazole may be a suitable agent for radionuclide imaging of hypoxic myocardium.

Intravenous streptokinase for acute myocardial infarction. Effects on global and regional systolic function.

The Western Washington Intravenous Streptokinase Trial randomized 368 patients with acute myocardial infarction to receive either intravenous streptokinase or standard therapy. The ventriculograms and coronary angiograms obtained in 170 patients 10.4 +/- 7.4 days after infarction were analyzed to evaluate the effects of thrombolytic therapy on global and regional systolic function. Streptokinase treatment resulted in a higher patency rate of the infarct-related artery (68.5%) than did standard therapy (44.8%) (p = 0.003). Ejection fraction was higher in streptokinase-treated patients (54% vs. 51%, p = 0.056), and the difference was most marked in patients with anterior myocardial infarction (53% vs. 44%, p = 0.03). Regional wall motion was measured by the centerline method and expressed in mean +/- SD motion in 52 normal subjects. There was a trend toward better function of the infarct zone in streptokinase-treated patients (SD, -2.48 vs. -2.70, p = 0.24). Additionally, streptokinase-treated patients had significantly better wall motion of noninfarct areas (SD, 0.36 vs. -0.08, p = 0.02). Treatment effects on function of noninfarct regions were most apparent in the subset of patients with multivessel disease. Thus, intravenous streptokinase preserves left ventricular function in patients with acute myocardial infarction. This benefit includes favorable effects on the function of regions remote from the site of infarction.