Comparative specialization of intrinsic cardiac neurons in humans, mice, and pigs

Intrinsic cardiac neurons (ICNs) play a crucial role in the proper functioning of the heart; yet a paucity of data pertaining to human ICNs exists. We took a multidisciplinary approach to complete a detailed cellular comparison of the structure and function of ICNs from mice, pigs, and humans. Immunohistochemistry of whole and sectioned ganglia, transmission electron microscopy, intracellular microelectrode recording and dye filling for quantitative morphometry were used to define the neurophysiology, histochemistry, and ultrastructure of these cells across species. The densely packed, smaller ICNs of mouse lacked dendrites, formed axosomatic connections, and had high synaptic efficacy constituting an obligatory synapse. At Pig ICNs, a convergence of subthreshold cholinergic inputs onto extensive dendritic arbors supported greater summation and integration of synaptic input. Human ICNs were tonically firing, with synaptic stimulation evoking large suprathreshold excitatory postsynaptic potentials like mouse, and subthreshold potentials like pig. Ultrastructural examination of synaptic terminals revealed conserved architecture, yet small clear vesicles (SCVs) were larger in pigs and humans. The presence and localization of ganglionic neuropeptides was distinct, with abundant VIP observed in human but not pig or mouse ganglia, and little SP or CGRP in pig ganglia. Action potential waveforms were similar, but human ICNs had larger after-hyperpolarizations. Intrinsic excitability differed; 93% of human cells were tonic, all pig neurons were phasic, and both phasic and tonic phenotypes were observed in mouse. In combination, this publicly accessible, multimodal atlas of ICNs from mice, pigs, and humans identifies similarities and differences in the evolution of ICNs.

Heterogeneous cardiac sympathetic innervation gradients promote arrhythmogenesis in murine dilated cardiomyopathy

Ventricular arrhythmias (VAs) in heart failure are enhanced by sympathoexcitation. However, radiotracer studies of catecholamine uptake in failing human hearts demonstrate a proclivity for VAs in patients with reduced cardiac sympathetic innervation. We hypothesized that this counterintuitive finding is explained by heterogeneous loss of sympathetic nerves in the failing heart. In a murine model of dilated cardiomyopathy (DCM), delayed PET imaging of sympathetic nerve density using the catecholamine analog [11C]meta-Hydroxyephedrine demonstrated global hypoinnervation in ventricular myocardium. Although reduced, sympathetic innervation in 2 distinct DCM models invariably exhibited transmural (epicardial to endocardial) gradients, with the endocardium being devoid of sympathetic nerve fibers versus controls. Further, the severity of transmural innervation gradients was correlated with VAs. Transmural innervation gradients were also identified in human left ventricular free wall samples from DCM versus controls. We investigated mechanisms underlying this relationship by in silico studies in 1D, 2D, and 3D models of failing and normal human hearts, finding that arrhythmogenesis increased as heterogeneity in sympathetic innervation worsened. Specifically, both DCM-induced myocyte electrical remodeling and spatially inhomogeneous innervation gradients synergistically worsened arrhythmogenesis. Thus, heterogeneous innervation gradients in DCM promoted arrhythmogenesis. Restoration of homogeneous sympathetic innervation in the failing heart may reduce VAs.

Electrophysiology and Arrhythmogenesis in the Human Right Ventricular Outflow Tract

BACKGROUND

Right ventricular outflow tract (RVOT) is a common source of ventricular tachycardia, which often requires ablation. However, the mechanisms underlying the RVOT's unique arrhythmia susceptibility remain poorly understood due to lack of detailed electrophysiological and molecular studies of the human RVOT.

METHODS

We conducted optical mapping studies in 16 nondiseased donor human RVOT preparations subjected to pharmacologically induced adrenergic and cholinergic stimulation to evaluate susceptibility to arrhythmias and characterize arrhythmia dynamics.

RESULTS

We found that under control conditions, RVOT has shorter action potential duration at 80% repolarization relative to the right ventricular apical region. Treatment with isoproterenol (100 nM) shortened action potential duration at 80% repolarization and increased incidence of premature ventricular contractions (P=0.003), whereas acetylcholine (100 μM) stimulation alone had no effect on action potential duration at 80% repolarization or premature ventricular contractions. However, acetylcholine treatment after isoproterenol stimulation reduced the incidence of premature ventricular contractions (P=0.034) and partially reversed action potential duration at 80% repolarization shortening (P=0.029). Immunolabeling of RVOT (n=4) confirmed the presence of cholinergic marker VAChT (vesicular acetylcholine transporter) in the region. Rapid pacing revealed RVOT susceptibility to both concordant and discordant alternans. Investigation into transmural arrhythmia dynamics showed that arrhythmia wave fronts and phase singularities (rotors) were relatively more organized in the endocardium than in the epicardium (P=0.006). Moreover, there was a weak but positive spatiotemporal autocorrelation between epicardial and endocardial arrhythmic wave fronts and rotors. Transcriptome analysis (n=10 hearts) suggests a trend that MAPK (mitogen-activated protein kinase) signaling, calcium signaling, and cGMP-PKG (protein kinase G) signaling are among the pathways that may be enriched in the male RVOT, whereas pathways of neurodegeneration may be enriched in the female RVOT.

CONCLUSIONS

Human RVOT electrophysiology is characterized by shorter action potential duration relative to the right ventricular apical region. Cholinergic right ventricular stimulation attenuates the arrhythmogenic effects of adrenergic stimulation, including increase in frequency of premature ventricular contractions and shortening of wavelength. Right ventricular arrhythmia is characterized by positive spatial-temporal autocorrelation between epicardial-endocardial arrhythmic wave fronts and rotors that are relatively more organized in the endocardium.

A single cell transcriptomics map of paracrine networks in the intrinsic cardiac nervous system

We developed a spatially-tracked single neuron transcriptomics map of an intrinsic cardiac ganglion, the right atrial ganglionic plexus (RAGP) that is a critical mediator of sinoatrial node (SAN) activity. This 3D representation of RAGP used neuronal tracing to extensively map the spatial distribution of the subset of neurons that project to the SAN. RNA-seq of laser capture microdissected neurons revealed a distinct composition of RAGP neurons compared to the central nervous system and a surprising finding that cholinergic and catecholaminergic markers are coexpressed, suggesting multipotential phenotypes that can drive neuroplasticity within RAGP. High-throughput qPCR of hundreds of laser capture microdissected single neurons confirmed these findings and revealed a high dimensionality of neuromodulatory factors that contribute to dynamic control of the heart. Neuropeptide-receptor coexpression analysis revealed a combinatorial paracrine neuromodulatory network within RAGP informing follow-on studies on the vagal control of RAGP to regulate cardiac function in health and disease.

Innervation and Neuronal Control of the Mammalian Sinoatrial Node a Comprehensive Atlas

[Figure: see text].

Immunohistochemical analysis of the mouse celiac ganglion: An integrative relay station of the peripheral nervous system

Celiac ganglia are important sites of signal integration and transduction. Their complex neurochemical anatomy has been studied extensively in guinea pigs but not in mice. The goal of this study was to provide detailed neurochemical characterization of mouse celiac ganglia and noradrenergic nerves in two target tissues, spleen and stomach. A vast majority of mouse celiac neurons express a noradrenergic phenotype, which includes tyrosine hydroxylase (TH), vesicular monoamine transporter 2, and the norepinephrine transporter. Over 80% of these neuron also express neuropeptide Y (NPY), and this coexpression is maintained by dissociated neurons in culture. Likewise, TH and NPY were colocalized in noradrenergic nerves throughout the spleen and in stomach blood vessels. Somatostatin was not detected in principal neurons but did occur in small, TH-negative cells presumed to be interneurons and in a few varicose nerve fibers. Cholinergic nerves provided the most abundant input to the ganglia, and small percentages of these also contained nitric oxide synthase or vasoactive intestinal polypeptide. A low-to-moderate density of nerves also stained separately for the latter markers. Additionally, nerve bundles and varicose nerve fibers containing the sensory neuropeptides, calcitonin gene-related polypeptide, and substance P, occurred at variable density throughout the ganglia. Collectively, these findings demonstrate that principal neurons of mouse celiac ganglia have less neurochemical diversity than reported for guinea pig and other species but receive input from nerves expressing an array of neurochemical markers. This profile suggests celiac neurons integrate input from many sources to influence target tissues by releasing primarily norepinephrine and NPY.

Spectroscopic evidence of silica-lignin complexes: implications for treatment of non-wood pulp wastewater

This research examined the hypothesis that lignin compounds form aqueous complexes with silica increasing its solubility, thereby inhibiting its precipitation. An experimental program using four lignin model compounds was conducted to test the hypothesis. Laser Raman spectroscopy (LRS) was used to characterize, qualitatively, the interaction between lignin and aqueous silica, and to identify the possibility of silica-lignin complexation. Solubility studies were then performed by analyzing the solubility of silica in presence and absence of lignin within the relevant pH range to confirm the results of LRS, and to obtain a quantitative assessment of the relative solubility. The findings have established the formation of silica-ferulic, silica-vanillic, and silica-4-methoxycinnamic acid complexes, but no evidence was detected for the formation of silica-veratryl alcohol complex. In fact, the black liquor undoubtedly contains much more complex lignin materials than the simple model compounds used in this work. The more complex lignin compounds are likely to have an even greater tendency to form silica complexes, thus contributing to the initial hypothesis. This finding provides a fundamental understanding as to why previous efforts to precipitate silica by lowering the pH from 10-11 (for black liquor) to less than 9 did not achieve satisfactory silica separation, and why alternative strategies need to be investigated.

Recommended design for more accurate duplication of natural conditions in salt marsh creation

Construction of 653 ha of salt marsh habitat from dredged material near the Aransas National Wildlife Refuge, Texas, has been proposed, with the goal of increasing the area of habitat available to endangered whooping cranes ( Grus americana). We assessed prototype created wetlands, and their similarity to natural reference sites, in terms of topography, vegetation, and hydrology. The created sites were steeply sloped relative to natural sites and were dominated by monotypic stands of Spartina alterniflora. Natural sites were dominated by vegetation more tolerant of desiccation and hypersalinity and by unvegetated salt pans. Differences in vegetation communities and distributions of habitat types resulted from efforts to enhance habitat diversity in created marsh cells through manipulation of marsh topography. However, the scale at which this diversity occurred in natural marsh of the study area was not considered. When constructing wetlands in cellular configurations, we recommend creation of large complexes of adjoining, hydrologically linked, cells wherein the desired habitat diversity is created at the scale of the entire complex, rather than within a single cell. Suggested design modifications would increase the similarity of created marshes to natural reference sites, potentially improving habitat function.

Simple mass balance approach for assessment of flood control sumps in an urban watershed: case study of heavy metal loading

Levee sump systems are used by many riverine communities for temporary storage of urban wet weather flows. The complex hydraulics and transport of stormwater pollutants in sump systems, however, have not been systematically studied. The objective of this work is to present a case study, utilizing a relatively simple and low-cost methodology, for assessing the hydraulic performance of flood control sumps in an urban watershed. Two sumps of highly variable physical and hydraulic characteristics were selected for analysis. HEC-1 software was used to estimate the flow hydrograph for each outfall to a sump as part of the overall flow balance, resulting in a total runoff hydrograph for a precipitation event. To validate HEC-1 results, a water balance was used to estimate the total runoff using sump operational data. The results suggest that HEC-1 calculation provide a satisfactory estimate of the total runoff and its time-distribution to the sump. The hydraulic model was then used to estimate nonpoint loads of selected heavy metals to the sump and to the river. Although flow of stormwater through a sump system is regulated solely by flood-control requirements, these sumps may function as sedimentation basins that provide purification of stormwater. An example calculation of removal of heavy metals in a sump using a mass balance approach is presented.

Improved experimental limits on the production of magnetic monopoles

We present new limits on low mass accelerator-produced pointlike Dirac magnetic monopoles trapped and bound in matter surrounding the D0 collision region of the Tevatron at Fermilab (experiment E-882). In the context of a Drell-Yan mechanism, we obtain cross section limits for the production of monopoles with magnetic charge values of 1, 2, 3, and 6 times the minimum Dirac charge of the order of picobarns, some 100 times smaller than found in similar previous Fermilab searches. Mass limits inferred from these cross section limits are presented.

Heavy metal contaminants removal by soil washing

The feasibility of soil washing for decontaminating a silty sand spiked with cadmium, chromium, lead, and zinc was evaluated in laboratory-scale batch and column experiments. Soil samples were subjected to chelant extraction using a solution of disodium salt of ethylenediaminetetraacetic acid (Na(2)EDTA), sodium metabisulfite (Na(2)S(2)O(5)) solution (an inexpensive reducing reagent), and a solution containing a mixture of the two reagents. Batch and column washing of the contaminated soil with deionized water (DI water) revealed that approximately 70% of the cadmium in the sample is weakly bound and readily mobilized in aqueous solution at neutral pH, followed by approximately 25%-30% of zinc, approximately 20%-25% chromium, and only approximately 10% of lead. Of the washing reagents tested, Na(2)EDTA solutions were generally more effective than Na(2)S(2)O(5) for removing heavy metals from the soil samples. Na(2)EDTA preferentially extracted lead over zinc and cadmium but exhibited little impact on chromium removal. Cadmium and, especially zinc, removal by a 0.01-M Na(2)EDTA solution were enhanced considerably by inclusion of 0.1 M Na(2)S(2)O(5), suggesting that a mixture of the two reagents may provide an economically optimum solution for certain contaminated soils.

5-HT induces cAMP production in crypt colonocytes at a 5-HT4 receptor

Previous studies demonstrate that both 5-hydroxytryptamine (5-HT) and cyclic AMP (cAMP) induce chloride efflux from crypt colonocytes in the rat distal colon; antagonist studies suggest that the 5-HT response is mediated primarily by the 5-HT4 receptor. Since this receptor is known to be positively coupled to adenylate cyclase, we postulated that 5-HT should induce generation of cAMP, which should be inhibited by 5-HT4 antagonists. Method. Mucosal cells from rat distal colon were taken by a sequential calcium chelation technique for enrichment of crypt cells. Cytokeratin stains demonstrated that >99% of cells were colonocytes. [3H]Thymidine uptake studies demonstrate a fivefold increased incorporation in this cell preparation compared to earlier fractions. 3-Isobutyl-l-methylxanthine (IBMX, 100 microM) was added to all cell suspensions in order to prevent cAMP metabolism. Cell suspensions were incubated for 2 min at 37 degreesC with different concentrations of 5-HT (n = 7). cAMP was measured by enzyme immunoassay. In another series of experiments, 5-HT (0.3 microM) stimulation of cAMP was similarly measured in the presence and absence of 5-HT receptor antagonists: 10 microM 5-HTP-DP (5-HT1P; n = 4), 0.1 microM ketanserin (5-HT2A; n = 4), 0.3 microM ondansetron (5-HT3; n = 4), 3 microM tropisetron (5-HT3 and 5-HT4; n = 4), and 10 nM GR-113808 (5-HT4; n = 5). Results. 5-HT produced a dose-dependent increase in cAMP. The increase was significant at concentrations >/=0.3 microM when compared to cells incubated with IBMX alone. In the second series of experiment, 5-HT-induced generation of cAMP at a dose of 0.3 microM was significantly inhibited in the presence of GR-113808 and tropisetron. Conclusion. 5-HT acts at a 5-HT4 receptor to induce production of cAMP in rat distal crypt colonocytes.

Ambient but not incremental oxidant generation effects intercellular adhesion molecule 1 induction by tumour necrosis factor alpha in endothelium

Proinflammatory cytokines upregulate endothelial adhesion molecule expression, thereby initiating the microvascular inflammatory response. We re-evaluated the reported role of reactive oxygen metabolites (ROMs) in signalling upregulation of intercellular adhesion molecule 1 (ICAM-1) on endothelial cells by tumour necrosis factor alpha (TNF-alpha) in vitro. TNF-alpha upregulation of endothelial-cell ICAM-1 expression was inhibited by the cell-permeable antioxidants, or by the adenovirus-mediated intracellular overexpression of Cu,Zn-superoxide dismutase, but not by the exogenous (extracellular) administration of the cell-impermeable antioxidants, superoxide dismutase and/or catalase. This ICAM-1 upregulation was also inhibited by inhibitors of NADH dehydrogenase, cytochrome bc1 complex and NADPH oxidase. However, a measurable increase in net cellular ROM generation in response to TNF-alpha was not seen using four disparate sensitive ROM assays. Moreover, the stimulation of exogenous or endogenous ROM generation did not upregulate ICAM-1, nor enhance ICAM-1 upregulation by TNF-alpha. These findings suggest that an ambient background flux of ROMs, generated intracellularly, but not their net incremental generation, is necessary for TNF-alpha to induce ICAM-1 expression in endothelium in vitro.

Protein tyrosine phosphorylation mediates TNF-induced endothelial-neutrophil adhesion in vitro

Proinflammatory cytokines initiate the vascular inflammatory response via the upregulation of adhesion molecules on the luminal endothelial surface. We investigated directly the role of protein tyrosine phosphorylation in the upregulation of the endothelial adhesion molecules, intercellular adhesion molecule 1 (ICAM-1) and E-selectin, and the consequent adhesion of neutrophils, after tumor necrosis factor (TNF)-alpha-stimulation of human aortic endothelial cells in vitro. Time- and dose-dependent TNF-alpha-stimulated ICAM-1 and E-selectin upregulation and neutrophil adhesion each were suppressed by tyrosine kinase inhibitors, including genistein (200 microM), but not genistein, its isoflavone analog without tyrosine kinase inhibitory activity. Tyrphostin AG 126, a synthetic selective tyrosine kinase inhibitor, also suppressed ICAM-1 and E-selectin upregulation and neutrophil adhesion, each in a dose-dependent manner, whereas tyrphostin AG 1288 had no effect. Tyrosine phosphorylation of two proteins (85 and 145 kDa in the cytoskeleton fraction) found minutes after TNF-alpha-stimulation was also inhibited by genistein. These findings suggest that, in endothelial cells, TNF-alpha upregulates ICAM-1 and E-selectin expression and consequent neutrophil adhesion via protein tyrosine phosphorylation.

Role of reactive oxygen metabolites in murine peritoneal macrophage phagocytosis and phagocytic killing

This study was designed to quantify the role of reactive oxygen metabolites (ROMs) in two distinct components of murine peritoneal macrophage activity, phagocytosis and killing, and to discriminate quantitatively the degree to which each component is dependent on NADPH oxidase and/or xanthine oxidase. A fluorochromatic vital staining technique was modified to simultaneously quantify phagocytosis and microbicidal activity of macrophages incubated with Candida parapsilosis targets. To determine the role of ROMs, macrophages were preincubated with free radical scavengers [superoxide dismutase (SOD) and/or catalase] or with selective inhibitors of xanthine oxidase (XO, e.g., allopurinol) or NADPH oxidase [diphenyleneiodonium (DPI)]. Phagocytosis was not affected by treatment of macrophages with SOD, catalase, allopurinol, or DPI. Candidacidal activity, however, was inhibited by SOD, allopurinol, or DPI. The inhibitory effects of DPI and allopurinol were additive. Histochemical and biochemical assays demonstrated substantial quantities of XO in murine peritoneal macrophages. The findings suggest that the generation of ROMs by XO- and NADPH oxidase-dependent pathways are each important for phagocytic killing by murine peritoneal macrophages.

Identification of a 5-hydroxytryptamine (5-HT2) receptor on guinea pig small intestinal crypt cells

Radioligand labeling of [3H]ketanserin was examined in suspensions of dispersed guinea pig small intestinal mucosal cells prepared by modification of the EDTA-chelation method described by M. M. Weiser (J. Biol. Chem. 248: 2536-2541, 1973). Preferential incorporation of [3H]thymidine was used to confirm that suspensions were enriched in crypt cells. At 25 degrees C, binding of [3H]ketanserin to dispersed enterocytes was rapid, maximal by 5 min, saturable (dissociation constant = 1.5 nM), 65 +/- 5% specific, stable, and reversible. The maximal number of binding sites per cell was 92,000 (range 86,000-105,500). Binding was temperature dependent, with maximal binding at 37 degrees C, and was inhibited by 5-hydroxytryptamine (5-HT) (half-maximal inhibition of [3H]ketanserin binding observed in response to 1 microM 5-HT) and ketanserin (half-maximal inhibition of [3H]ketanserin binding observed in response to 1 nM ketanserin) but not by the 5-HT1P antagonist N-acetyl-5-hydroxytryptophyl 5-hydroxytryptophan amide (5-HTP-DP) or the 5-HT3 antagonist 3-tropanyl-indole-3-carboxylate methiodide (ICS-205-930). The second messenger system coupled to the putative mucosal 5-HT2 receptor was examined. 5-HT stimulated a concentration-dependent production of inositol 1,4,5-trisphosphate (IP3) in the dispersed enterocytes. This was maximal at 1 min and was inhibited in a concentration-dependent manner by ketanserin. 5-HTP-DP and ICS-205-930 had no effect on 5-HT-stimulated production of IP3. These data provide evidence for the existence of a mucosal 5-HT2 receptor located on guinea pig small intestinal crypt cells.

Induction of heat shock response leads to apoptosis in endothelial cells previously exposed to endotoxin

The homeostatic response of complex eukaryotes to the challenge of environmental stress includes the induction of several programs of gene expression; among them are those for the acute phase genes and those for the heat shock genes. In some systems, the heat shock response, which is often elicited by more severe stimuli, preempts the acute phase response, which is seen in response to less severe challenges, as well as constitutive gene expression. Nevertheless, each response appears to provide a natural selective advantage for survival of the organism in a toxic environment. However, when cultured porcine endothelial cells were exposed first to a nonlethal level of bacterial endotoxin lipopolysaccharide (LPS), an inducer of the acute phase response, and then, simultaneously to standard stimuli, which normally elicit a salutary heat shock response, the cells died manifesting a pattern of DNA fragmentation (nucleolysis) characteristic of programmed cell death (apoptosis). The treatment of LPS-exposed cells with cycloheximide to block protein synthesis reproduced the lethal apoptosis that had been elicited by the induction of heat shock gene expression. Therefore, the preemption of other programs of stress gene expression by the prioritized expression of heat shock genes is associated with apoptosis.

Synthesis and use of the n-bromododecane-1,12-diols as conformational probes for general anesthetic target sites

The n-bromododecane-1,12-diols with bromine on carbons 2, 3, 5, and 6, respectively, were synthesized and found to be potent general anesthetics. They were also found to be potent inhibitors of firefly luciferase, a protein model for the primary target sites underlying general anesthesia. However, their effects on lipid bilayers were small, lowering the chain-melting phase transition temperature by less than 1 degree C at their EC50 concentrations for general anesthesia. A large dependence upon the position of the bromine atom was found for both n-hexadecane/water partition coefficients and inhibition constants for firefly luciferase; a much smaller positional dependence was found for induction of general anesthesia and for disrupting lipids. These results are consistent with the bulky bromine atom inhibiting the conformational flexibility of the diol hydrocarbon chain, making these bromo diols useful probes for ascertaining the shapes of apolar binding sites. In particular, our measurements suggest that these novel anesthetics produce general anesthesia by binding to long and relatively narrow apolar target sites in the central nervous system.

A double-blind, multicenter comparison of 0.05% halobetasol propionate ointment and 0.05% clobetasol propionate ointment in patients with chronic, localized plaque psoriasis

In a double-blind, parallel-group, multicenter trial in 134 patients with severe, localized, plaque psoriasis, the success rate (described as "healed" or "marked improvement") at the end of the study was 96% in the halobetasol propionate group and 91% in the clobetasol propionate group. A significantly larger proportion of patients treated with halobetasol had no disease or mild disease after 14 days compared with those treated with clobetasol (86% versus 70%, p = 0.023). Healing within 24 days of starting treatment was noted in 69% and 56% of patients treated with halobetasol and clobetasol, respectively. Adverse effects were reported in a smaller percentage of patients treated with halobetasol propionate ointment than in those treated with clobetasol propionate ointment (7% versus 12%). Cosmetic acceptability and ease of application were recorded as "very good" in a larger percentage of patients treated with halobetasol propionate ointment than in the group treated with clobetasol propionate (90% versus 80%).

Complications of percutaneous abdominal fine-needle biopsy. Review

To determine whether the increasing use of percutaneous fine-needle biopsy of abdominal lesions is associated with an increase in serious complications, the author updated a literature search and evaluated a questionnaire (distributed among selected hospitals in the United States in 1986 and 1987) that followed up a questionnaire distributed in 1983. The updated literature review revealed a total of 24 deaths and 20 needle tract seedings. The updated questionnaire revealed five deaths after 16,381 biopsies (0.031%), whereas the previous questionnaire had shown four deaths after 63,108 biopsies (0.006%). Two similar European questionnaires revealed mortality rates of 0.008% and 0.018%, respectively. Of the total of 33 deaths, 21 involved biopsies of liver lesions; six involved pancreatic biopsies. Seventeen of the 21 deaths after liver biopsies were secondary to hemorrhage; five of the six deaths after pancreatic biopsies were due to pancreatitis. Of the 23 instances of needle tract seeding, 10 occurred after biopsies of pancreatic malignancies. The frequencies of needle tract seeding in the four questionnaires were 0.005%, 0.006%, 0.003%, and 0.009%, respectively. Although infrequent, serious complications may be associated with this procedure. The author makes suggestions that may help minimize them.

Complications of percutaneous abdominal fine-needle biopsy. Review

To determine whether the increasing use of percutaneous fine-needle biopsy of abdominal lesions is associated with an increase in serious complications, the author updated a literature search and evaluated a questionnaire (distributed among selected hospitals in the United States in 1986 and 1987) that followed up a questionnaire distributed in 1983. The updated literature review revealed a total of 24 deaths and 20 needle tract seedings. The updated questionnaire revealed five deaths after 16,381 biopsies (0.031%), whereas the previous questionnaire had shown four deaths after 63,108 biopsies (0.006%). Two similar European questionnaires revealed mortality rates of 0.008% and 0.018%, respectively. Of the total of 33 deaths, 21 involved biopsies of liver lesions; six involved pancreatic biopsies. Seventeen of the 21 deaths after liver biopsies were secondary to hemorrhage; five of the six deaths after pancreatic biopsies were due to pancreatitis. Of the 23 instances of needle tract seeding, 10 occurred after biopsies of pancreatic malignancies. The frequencies of needle tract seeding in the four questionnaires were 0.005%, 0.006%, 0.003%, and 0.009%, respectively. Although infrequent, serious complications may be associated with this procedure. The author makes suggestions that may help minimize them.

CT of the pancreas with a fat-density oral contrast regimen

Visualization of the head of the pancreas by CT was prospectively evaluated in two groups of 100 patients who did not have pancreatic disease. Patients were given either a fat-density oral contrast material (12.5% corn-oil emulsion and metoclopramide) or a conventional high-density oral contrast material (barium suspension or iodinated solution). There was no statistically significant difference in the subjects' tolerance to the two regimens. There was, however, a significant improvement in ability to distinguish the head of the pancreas from the duodenal C-loop when the fat-density contrast material was given. When pancreaticoduodenal discrimination was graded, patients given corn-oil emulsion and metoclopramide received an average score of 0.94, whereas those given the high-density agent received an average score of 0.74, with 1.00 being the highest possible score (p less than .005). These data suggest that for routine CT evaluation of the head of the pancreas, a combination of corn-oil emulsion and metoclopramide may be superior to the conventional high-density oral contrast agents given without metoclopramide.

Beta-adrenoceptors on duodenal mucosal cells mediate venous serotonin release

We have previously documented predominant intraluminal release of serotonin (5-HT) following activation of muscarinic receptors on enterochromaffin cells. Gronstad et al. reported that portal venous release of 5-HT in response to vagal stimulation was mediated by beta-adrenergic receptors. The purpose of this study was to determine whether 5-HT release induced by the beta-adrenergic agonist, isoproterenol, is mediated by enteric nerves or is a direct action at the enterochromaffin cell level. We mounted rabbit duodenal mucosal sheets stripped of muscularis in modified Ussing chambers and measured release of 5-HT in response to 10(-5) M isoproterenol, in the presence and absence of the neural conduction blocker tetrotoxin, 10(-6) M. Serotonin was measured in the buffer bathing the mucosal and submucosal surfaces by HPLC. In the presence of isoproterenol, total (mucosal and submucosal) 5-HT release (21.0 +/- 4.9 ng/cm2/45 min) was significantly (P less than 0.05) greater than that in untreated controls (7.8 +/- 2.7 ng/cm2/45 min); release was predominantly toward the submucosal surface. In the presence of tetrodotoxin alone, net 5-HT release was significantly (P less than 0.05) increased to 12.8 +/- 2.8 ng/cm2/45 min. In tetrodotoxin-treated mucosa, isoproterenol increased 5-HT release to 28.6 +/- 5.3 ng/cm2/45 min which was significantly greater (P less than 0.05) than that with tetrodotoxin alone. Since 5-HT release was increased even in the presence of neural blockade, these results suggest that activation of beta-adrenergic receptors on or near enterochromaffin cells induces release of 5-HT predominantly toward the submucosal surface.

Clinicians' appraisal of sonography

The perceived efficacy of sonography in making diagnostic and management decisions in clinical practice was determined through a questionnaire survey of physicians who had recently referred patients to a university radiology department. Of 2,178 questionnaires sent, 1,611 were returned (74%). Sensitivity and specificity of sonography, corrected for verification bias, were 72% and 84%. Referring physicians considered the studies to be of value in arriving at the final diagnosis and in the clinical management of patients in approximately two-thirds of the cases. Results were considered of no value and misleading in 4% of the cases. Sonography was more accurate and was reported to be valuable by approximately 10% more physicians when a specific indication for an examination could be identified rather than when indications were vague and when sonographic findings were abnormal rather than normal (P less than .005). In general, sonography was of equal value to both specialists and nonspecialists. The results of this study suggest that sonography is, and is perceived by clinicians to be, an accurate and valuable clinical diagnostic modality.

Fat-density oral contrast agent for abdominal CT

To overcome the problem of inadequate mixing of gastrointestinal (GI) tract contents with conventional high-density oral contrast agents in abdominal computed tomography (CT), a flavored 12.5% corn oil emulsion (COE) was tested as an oral contrast agent in 62 patients. The results were compared with those obtained from 105 patients who received high-density oral contrast agents. A simple patient preparation regimen for the COE was developed, which appears to be reasonably well tolerated by the patients and yields diagnostic studies comparable to those obtained with conventional agents. Use of the COE resulted in consistent discrimination of the GI tract and depiction of the GI wall. Preliminary data suggest that it may be particularly useful for CT evaluation of the stomach, duodenum, and pancreas; in patients suspected of having solid tumors; and in thin people.

Computed tomography of life-threatening complications of abdominal aortic aneurysm. The disrupted aortic wall

A localized disruption of the conspicuity of the wall of the aorta was noted on intravenous contrast-enhanced computed tomography (CT) scans of ten patients with ruptured abdominal aortic aneurysm (n = 6) or aortoenteric fistula (n = 4). Subsequently, we reviewed 84 scans of patients with uncomplicated aneurysm (n = 70) or aneurysm graft repair (n = 14) to determine if a disrupted wall has diagnostic implications. In this control group, the wall of the aneurysm was conspicuous throughout in 95% of 64 patients who received iodinated contrast material intravenously and in 55% of 20 patients who did not. In the proper clinical setting, CT scans performed with intravenous administration of iodinated contrast material can provide direct evidence of disruption of the wall of an abdominal aortic aneurysm. In selected cases, this may be important for the diagnosis of rupture. Disrupted conspicuity of the wall, in combination with effacement of the fat plane between an aneurysm and the juxtaposed intestine, increases the accuracy of CT for the diagnosis of aortoenteric fistula.

Imaging of the bowel wall. Computed tomography and fat density oral-contrast agent in an animal model

In this study, we reassessed the problems encountered in computed tomographic (CT) examinations performed with conventional bowel preparations, and developed a fat density oral contrast in dogs. Conventional high-density agents, water, fat (negative) density, and air were administered using a nasogastric tube to eight dogs (25 separate CT scans). Optimal and consistent identification of the gastrointestinal (GI) tract and mural visualization were achieved with 400 ml of 12.5% to 50% corn oil emulsions administered in four hourly divided doses. Mild diarrhea was observed with the 50% concentration only, but no untoward effect was noted clinically with 25% and 12.5% emulsions. Mixing the negative (fat) density oral contrast with the GI contents produced conditions optimal for high-CT contrast resolution of the GI wall. Standard intravenous administration of iodinated contrast agent enhanced mural visualization and, in conjunction with dynamic scanning, time density curves. This suggests that vascular perfusion could be portrayed. This animal model may be used for the experimental evaluation of a number of GI abnormalities, including ischemic, neoplastic, and inflammatory conditions.

Bile-duct dilatation after laparotomy: a potential effect of intestinal hypomotility

Dilatation of unobstructed extrahepatic bile ducts was observed in patients with conditions associated with intestinal hypomotility. For further investigation of this association, a prospective study was undertaken in which the common hepatic duct was measured in 15 patients before and 1 day after laparotomy, when all patients had postoperative paralytic ileus. A statistically significant (p less than 0.01) increase in the mean diameter of the hepatic duct was observed postoperatively. When compared with the preoperative measurement, the mean diameter of the duct almost doubled, from 3.3 to 5.9 mm. This phenomenon may be due to persistent contraction of the sphincter of Oddi that occurs when intestinal hypomotility eliminates the stimuli for cholecystokinin release.

Chronic acalculous gallbladder disease: multiimaging evaluation with clinical-pathologic correlation

Despite the recent advances in hepatobiliary imaging, the diagnosis of chronic acalculous gallbladder disease remains difficult. A retrospective study was undertaken to assess the value of a multiimaging approach in detecting chronic acalculous gallbladder disease and in predicting which patients would obtain symptomatic relief after cholecystectomy. Of 199 patients with chronic cholecystitis, 26 (13%) had no gallstones. Of these 26, only 17 (65%) had symptoms related to chronic cholecystitis; in the remainder, the histologic diagnosis was made incidentally. After cholecystectomy, 13 (76%) of the 17 symptomatic patients obtained long-term symptomatic relief, while in four, the symptoms recurred. Among patients with histologic changes of chronic cholecystitis, biliary scintigraphy was the most sensitive technique (sensitivity, 89%). The sensitivity of sonography and oral cholecystography was 61.5% and 66%, respectively. However, for identifying symptomatic patients who may obtain long-term symptomatic relief after cholecystectomy, the accuracy of sonography, oral cholecystography, and biliary scintigraphy was 82%, 86%, and 38%, respectively. When two tests were in agreement the accuracy was 88%. For chronic acalculous cholecystitis, more than one study must be performed in order to make the correct diagnosis and to predict good results from cholecystectomy.

The effect of time and cholecystectomy on experimental biliary tree dilatation. A multi-imaging evaluation

The changes of the biliary tree following distal bile duct obstruction and its release were confirmed by biliary scintigraphy and monitored by serial ultrasonography, computed tomography, and values of serum bilirubin and alkaline phosphatase in 14 mongrel dogs. The degree and rate of biliary dilatation were independent of cholecystectomy. The most rapid rate of extrahepatic dilatation occurred within the first 48 hours, while dilated intrahepatic ducts were first recognized three to six days after obstruction. Following release of the obstruction, the degree and rate of resolution of the biliary dilatation were independent of the duration of ligation (one vs. two weeks) and cholecystectomy. The dilatation resolved slowly. Dilated intrahepatic ducts were recognized for as long as eight to 13 days, while extrahepatic biliary dilatation was still present for 13 weeks, at which time the experiment was terminated. It is postulated that the extrahepatic biliary dilatation will approach a plateau approximately one month after total biliary obstruction. It appears that if the obstruction lasts more than one week, it results in irreversible damage to the elasticity of the extrahepatic ducts. Thus, after release of the obstruction, serial biliary imaging is indicated until a new baseline of the biliary tree diameter has been established.

Sarcoid dactylitis in black South African patients

Six black South Africans with sarcoid dactylitis are described. By the term sarcoid dactylitis we mean sarcoid involvement of the bone and soft tissue of the fingers. Three of the six patients developed dactylitis during the course of chronic sarcoid. These patients had multisystem disease. In all three patients dactylitis developed after the diagnosis of sarcoid was established. However, in the other three patients dactylitis was the presenting feature of sarcoidosis, and none of these patients had evidence of chronic fibrotic sarcoid elsewhere. This finding is at variance with the observation that bony sarcoid is always a feature of chronic, poor prognosis, fibrotic sarcoid of all organ systems; these patients may form a sub-group with bony involvement and good prognosis. The significance, however, of this latter localized presentation of sarcoid is that clinically and histologically it is easily confused with tuberculoid leprosy and has been misdiagnosed.

The hazards of fine-needle aspiration biopsy

Review of the literature and the results of the hospital survey substantiate the widely held belief that fine-needle aspiration biopsy is a very safe procedure. However, serious and even fatal complications, although rare, can and do occur and it is important to be aware of the possibility and to take all the appropriate precautions in order to reduce their incidence.

Pyoderma gangrenosum and ulcerative colitis in black South Africans. Case reports

Two patients with pyoderma gangrenosum and ulcerative colitis are described. To our knowledge this is the first report of such an association in Blacks. The unusual vesicopustular form of pyoderma gangrenosum was well demonstrated by one patient who also responded remarkably to clofazimine. The associations, pathological findings and therapy are briefly reviewed. Colectomy may ameliorate the skin lesions when conventional therapy is unsuccessful.

Pityriasis rotunda. A cutaneous sign of malignant disease in two patients

The term pityriasis rotunda refers to strikingly circular scaly lesions, with the histologic appearance of ichthyosis vulgaris. Pityriasis rotunda has been described in the Japanese, South African blacks, and West Indian blacks. The condition occurs only in association with certain serious systemic illnesses, usually tuberculosis, or malignant neoplasms or less severe diseases of the female genital tract (eg, fibroids, ovarian cyst). We describe two South African blacks with pityriasis rotunda and neoplasms. The cutaneous lesions cleared when the primary neoplasm was treated.

Diagnosis of peritoneal mesothelioma: computed tomography, sonography, and fine-needle aspiration biopsy

The diagnosis of peritoneal mesothelioma was made prospectively and noninvasively in four patients with the use of sonography, computed tomography, and sonographically guided fine-needle aspiration biopsy. The imaging methods revealed information similar to the operative findings, with clear superiority of computed tomography over sonography. These noninvasive methods may be used as screening tools, especially among groups or in regional areas with a high risk for asbestos exposure. The findings included soft-tissue masses with invariable involvement of the omentum; small intraperitoneal nodules; thickened peritoneum, mesentery, and bowel wall; pleural plaques; and usually minimal, if any, ascites. Since the differential diagnosis from peritoneal carcinomatosis may be difficult, sonographically (or CT) guided aspiration biopsy is needed to produce diagnostic cytologic specimens. The use of this type of biopsy should obviate surgical exploration.

Ultrasound in the diagnosis of a palpable abdominal mass. A prospective study of 107 patients

In 107 consecutive patients referred to the ultrasound laboratory for investigation of a palpable abdominal mass, the examination was performed without knowledge of clinical history, laboratory findings, or the results of other examinations. In 101 of the patients the correct diagnosis was subsequently verified, and 29 different ultrasonic diagnoses were reached. In 98 (97%) of the patients the ultrasonic diagnoses were correct. Two uterine leiomyomas were erroneously diagnosed as ovarian in origin, and a massive adrenal carcinoma was misdiagnosed as a hepatic tumor. It is suggested that ultrasonic scanning is the method of choice in evaluating patients with a palpable abdominal mass.

Pulmonary complications of chemotherapy regimens containing bleomycin

Twenty patients with pulmonary complications associated with combination chemotherapy regimens containing bleomycin were studied to determine common patterns of pulmonary radiographic abnormalities. All patients were receiving bleomycin on one of two different regimens of combination chemotherapy. Ten patients with non-Hodgkin lymphoma received a relatively low dose (22-64 mg total) and 10 patients with testicular cancer received a higher dose (360 mg total). The high-dose group showed subclinical radiographic lung toxicity changes in eight (80%) patients during and after therapy. Chronic pulmonary abnormalities were seen in nine (90%) patients in the high-dose group but in only three (30%) patients in the low-dose group. These was no significant difference in the pattern and distribution of lung infiltrates in these two groups. Infiltrates involving mainly the costophrenic triangle were seen in 18 (90%) patients; in six (33%) of these the changes were confined to the costophrenic triangles bilaterally and nearly symmetrically. Five (25%) patients had infiltrates at the periphery of the lungs. Elevation of the diaphragm was seen in 16 (80%) patients. A pleural reaction without gross effusion was seen in nine (45%) patients, of whom five (55%) demonstrated thickening of the interlobar fissures. Chronic lung changes were mostly confined to the bases in the form of failure of reexpansion of the costophrenic triangle (55%), persistent elevation of the diaphragm (35%), and a reticular meshwork of fibrosis at the costophrenic triangles (25%). Minimal lung disease was manifest as ground glass appearance at the lung bases and as fine, linear or reticulonodular densities that involved the costophrenic triangles.

Ultrasonographic-pathologic correlation of malignant hepatic masses

Characterization of the source of hepatic malignancy would be useful in directing a patient's workup, saving time and expense. We attempted to correlate the echographic appearance of malignant hepatic masses with the pathologic (44 patients) or clinical (1 patient) diagnosis in 45 consecutive patients scanned to evaluate this problem. In 31 patients the lesions were hyperechoic (28) or predominantly hyperechoic with central lucency. Of these lesions, 25 represented metastases from adenocarcinoma of the colon (17), pancreas (6), or unknown origin (2). Six patients with metastatic adenocarcinoma had predominantly echolucent lesions. Of the 14 malignancies of other histologic types, 6 were largely hyperechoic and could not be distinguished from adenocarcinoma metastases. No correlations could be drawn between the ultrasound patterns and the tumor source in this diverse group fo malignancies. In eight patients receiving chemotherapy, sequential examinations failed to reveal any alteration in the echographic patterns of their lesions. These results indicate that the ultrasound appearance of hepatic malignancy lacks specificity in defining the organ of origin. Such factors as homogeneity, vascularity, or desmoplastic response may be more important than cell type in producing the echographic pattern.