Griseofulvin Radiosensitizes Non-Small Cell Lung Cancer Cells and Activates cGAS

Extra copies of centrosomes are frequently observed in cancer cells. To survive and proliferate, cancer cells have developed strategies to cluster extra-centrosomes to form bipolar mitotic spindles. The aim of this study was to investigate whether centrosome clustering (CC) inhibition (CCi) would preferentially radiosensitize non-small cell lung cancer (NSCLC). Griseofulvin (GF; FDA-approved treatment) inhibits CC, and combined with radiation treatment (RT), resulted in a significant increase in the number of NSCLC cells with multipolar spindles, and decreased cell viability and colony formation ability in vitro. In vivo, GF treatment was well tolerated by mice, and the combined therapy of GF and radiation treatment resulted in a significant tumor growth delay. Both GF and radiation treatment also induced the generation of micronuclei (MN) in vitro and in vivo and activated cyclic GMP-AMP synthase (cGAS) in NSCLC cells. A significant increase in downstream cGAS-STING pathway activation was seen after combination treatment in A549 radioresistant cells that was dependent on cGAS. In conclusion, GF increased radiation treatment efficacy in lung cancer preclinical models in vitro and in vivo. This effect may be associated with the generation of MN and the activation of cGAS. These data suggest that the combination therapy of CCi, radiation treatment, and immunotherapy could be a promising strategy to treat NSCLC.

The impact of mitotic errors on cell proliferation and tumorigenesis

This review by Levine and Holland reviews the sources of mitotic errors in human tumors and their effect on cell fitness and transformation. They discuss new findings that suggest that chromosome missegregation can produce a proinflammatory environment and impact tumor responsiveness to immunotherapy and survey the vulnerabilities exposed by cell division errors and how they can be exploited therapeutically.

Mitosis is a delicate event that must be executed with high fidelity to ensure genomic stability. Recent work has provided insight into how mitotic errors shape cancer genomes by driving both numerical and structural alterations in chromosomes that contribute to tumor initiation and progression. Here, we review the sources of mitotic errors in human tumors and their effect on cell fitness and transformation. We discuss new findings that suggest that chromosome missegregation can produce a proinflammatory environment and impact tumor responsiveness to immunotherapy. Finally, we survey the vulnerabilities exposed by cell division errors and how they can be exploited therapeutically.

Centrosome Amplification Is Sufficient to Promote Spontaneous Tumorigenesis in Mammals

Centrosome amplification is a common feature of human tumors, but whether this is a cause or a consequence of cancer remains unclear. Here, we test the consequence of centrosome amplification by creating mice in which centrosome number can be chronically increased in the absence of additional genetic defects. We show that increasing centrosome number elevated tumor initiation in a mouse model of intestinal neoplasia. Most importantly, we demonstrate that supernumerary centrosomes are sufficient to drive aneuploidy and the development of spontaneous tumors in multiple tissues. Tumors arising from centrosome amplification exhibit frequent mitotic errors and possess complex karyotypes, recapitulating a common feature of human cancer. Together, our data support a direct causal relationship among centrosome amplification, genomic instability, and tumor development.

Polo-like kinase 4 shapes up

Polo-like kinase 4 (Plk4) is a master regulator of centriole duplication and targets to centrioles through the association of its cryptic polo box domain with centriole receptors. In this issue of Structure, Shimanovskaya and colleagues unveil a new dimeric architecture of Plk4's cryptic polo box that reveals a conserved mechanism for centriole targeting of the kinase.

Alterations in corticostriatal synaptic plasticity in mice overexpressing human alpha-synuclein

Most forms of Parkinson's disease (PD) are sporadic in nature, but some have genetic causes as first described for the alpha-synuclein gene. The alpha-synuclein protein also accumulates as insoluble aggregates in Lewy bodies in sporadic PD as well as in most inherited forms of PD. The focus of the present study is the modulation of synaptic plasticity in the corticostriatal pathway of transgenic (Tg) mice that overexpress the human alpha-synuclein protein throughout the brain (ASOTg). Paired-pulse facilitation was detected in vitro by activation of corticostriatal afferents in ASOTg mice, consistent with a presynaptic effect of elevated human alpha-synuclein. However basal synaptic transmission was unchanged in ASOTg, suggesting that human alpha-synuclein could impact paired-pulse facilitation via a presynaptic mechanism not directly related to the probability of neurotransmitter release. Mice lacking alpha-synuclein or those expressing normal and A53T human alpha-synuclein in tyrosine hydroxylase-containing neurons showed, instead, paired-pulse depression. High-frequency stimulation induced a presynaptic form of long-term depression solely in ASOTg striatum. A presynaptic, N-methyl-d-aspartate receptor-independent form of chemical long-term potentiation induced by forskolin (FSK) was enhanced in ASOTg striatum, while FSK-induced cAMP levels were reduced in ASOTg synaptoneurosome fractions. Overall the results suggest that elevated human alpha-synuclein alters presynaptic plasticity in the corticostriatal pathway, possibly reflecting a reduction in glutamate at corticostriatal synapses by modulation of adenylyl cyclase signaling pathways. ASOTg mice may recapitulate an early stage in PD during which overexpressed alpha-synuclein dampens corticostriatal synaptic transmission and reduces movement.

Gastric bezoars: reassessment of clinical and radiographic findings in 19 patients

The aim of this study was to reassess the clinical and radiographic findings in a series of patients with gastric bezoars. Radiology files revealed 19 patients with bezoars; 10 patients had CT and 10 had endoscopy before or after the barium studies. 11 patients (58%) had risk factors for gastroparesis and 6 (32%) had had previous gastric surgery, including 3 having had a gastric bypass or vertical banded gastroplasty. 18 patients (95%) had symptoms; in 10 of those patients, symptoms were present for 1 week or less (53%). On barium studies, the bezoars were round or ovoid in 17 patients (89%) and irregular in 2 (11%); mottled in 10 (53%) and homogeneous in 9 (47%); and mobile in 15 (79%) and immobile in 4 (21%). Gastroparesis was observed at fluoroscopy in 8 (62%) out of 13 patients without gastric surgery. Symptoms improved/resolved in 12 (67%) out of 18 patients. Follow-up CT or endoscopy showed resolution of the bezoars in 8 (80%) out of 10 patients; the mean interval to resolution was 12 days. Our experience suggests that gastroparesis is the single most common cause of bezoars, accounting for the majority of cases. Partial gastric resection or bariatric surgery should also be recognized as a cause of bezoar formation. These lesions may be manifested on barium studies by a spectrum of findings, appearing as mottled or homogeneous, mobile or immobile masses, sometimes filling the gastric pouch after bariatric surgery. Affected individuals often have an acute clinical presentation with symptoms for 1 week or less, and some bezoars resolve rapidly on conservative medical treatment.

Extensive early motor and non-motor behavioral deficits are followed by striatal neuronal loss in knock-in Huntington's disease mice

Huntington's disease is a neurodegenerative disorder, caused by an elongation of CAG repeats in the huntingtin gene. Mice with an insertion of an expanded polyglutamine repeat in the mouse huntingtin gene (knock-in mice) most closely model the disease because the mutation is expressed in the proper genomic and protein context. However, few knock-in mouse lines have been extensively characterized and available data suggest marked differences in the extent and time course of their behavioral and pathological phenotype. We have previously described behavioral anomalies in the open field as early as 1 month of age, followed by the appearance at 2 months of progressive huntingtin neuropathology, in a mouse carrying a portion of human exon 1 with approximately 140 CAG repeats inserted into the mouse huntingtin gene. Here we extend these observations by showing that early behavioral anomalies exist in a wide range of motor (climbing, vertical pole, rotarod, and running wheel performance) and non-motor functions (fear conditioning and anxiety) starting at 1-4 months of age, and are followed by progressive gliosis and decrease in dopamine and cyclic AMP-regulated phosphoprotein with molecular weight 32 kDa (DARPP32) (12 months) and a loss of striatal neurons at 2 years. At this age, mice also present striking spontaneous behavioral deficits in their home cage. The data show that this line of knock-in mice reproduces canonical characteristics of Huntington's disease, preceded by deficits which may correspond to the protracted pre-manifest phase of the disease in humans. Accordingly, they provide a useful model to elucidate early mechanisms of pathophysiology and the progression to overt neurodegeneration.

Gastritis from NSAIDS to Helicobacter pylori

Gastritis is a histologic diagnosis. To understand gastritis, the radiologist must have some working knowledge of gastric histology and pathology. Therefore, this article first describes normal histologic and radiologic anatomy. The pathology of gastritis is then presented to give the radiologist a basis for understanding the radiologic findings. Finally, gastritis is discussed from a clinical and radiologic perspective.

Early behavioral deficits in R6/2 mice suitable for use in preclinical drug testing

Huntington's disease (HD) is a neurodegenerative disorder caused by an elongated glutamine repeat in huntingtin. Improved understanding of the molecular effects of the mutation opens new avenues for treatment. High-throughput automated behavioral tests that produce well-defined markers of disease progression are necessary for in vivo drug screening. We have identified early behavioral deficits in tests of motor function that are amenable to cost effective automated analysis in a mouse model of HD. Running wheel activity and climbing behavior were reduced in R6/2 HD transgenics from as early as 4.5 weeks of age, at a time when rotarod performance and grip strength were still normal. Power calculations showed that the running wheel test was appropriate for efficient, high-throughput drug screening at this early age. Furthermore, the data extend the range of behavioral deficits observed in 1-month-old R6/2 mice, an age when synaptic dysfunction can already be detected in the striatum.

Pediatric Cortical Dysplasia: Correlations between Neuroimaging, Electrophysiology and Location of Cytomegalic Neurons and Balloon Cells and Glutamate/GABA Synaptic Circuits

Seizures in cortical dysplasia (CD) could be from cytomegalic neurons and balloon cells acting as epileptic 'pacemakers', or abnormal neurotransmission. This study examined these hypotheses using in vitro electrophysiological techniques to determine intrinsic membrane properties and spontaneous glutamatergic and GABAergic synaptic activity for normal-pyramidal neurons, cytomegalic neurons and balloon cells from 67 neocortical sites originating from 43 CD patients (ages 0.2-14 years). Magnetic resonance imaging (MRI), (18)fluoro-2-deoxyglucose positron emission tomography (FDG-PET) and electrocorticography graded cortical sample sites from least to worst CD abnormality. Results found that cytomegalic neurons and balloon cells were observed more frequently in areas of severe CD compared with mild or normal CD regions as assessed by FDG-PET/MRI. Cytomegalic neurons (but not balloon cells) correlated with the worst electrocorticography scores. Electrophysiological recordings demonstrated that cytomegalic and normal-pyramidal neurons displayed similar firing properties without intrinsic bursting. By contrast, balloon cells were electrically silent. Normal-pyramidal and cytomegalic neurons displayed decreased spontaneous glutamatergic synaptic activity in areas of severe FDG-PET/MRI abnormalities compared with normal regions, while GABAergic activity was unaltered. In CD, these findings indicate that cytomegalic neurons (but not balloon cells) might contribute to epileptogenesis, but are not likely to be 'pacemaker' cells capable of spontaneous paroxysmal depolarizations. Furthermore, there was more GABA relative to glutamate synaptic neurotransmission in areas of severe CD. Thus, in CD tissue alternate mechanisms of epileptogenesis should be considered, and we suggest that GABAergic synaptic circuits interacting with cytomegalic and normal-pyramidal neurons with immature receptor properties might contribute to seizure generation.

Transient failure of opening of the lower oesophageal sphincter on upright oesophagrams: radiographic and clinical findings

The purpose of our study was to determine the frequency, radiographic features, and clinical importance of transient failure of opening of the lower oesophageal sphincter (LOS) on upright double-contrast views of the oesophagus. A computerized search of radiology records identified 16 patients who had transient failure of opening of the LOS on upright views from biphasic oesophagrams or upper gastrointestinal tract examinations using high-density barium but normal opening of the LOS on prone views using low-density barium. The radiographic findings were reviewed and correlated with the clinical and manometric findings. In all cases, barium studies revealed tapered, beaklike narrowing of the distal oesophagus on upright double-contrast views, with a normal-appearing distal oesophagus, normal opening of the LOS, and intact peristalsis on prone single-contrast views. Only seven patients (44%) had dysphagia. Five of these patients had clinical follow-up, and the dysphagia improved or resolved without specific treatment for LOS dysfunction in four. The remaining patient had persistent dysphagia, but this individual had polymyositis as the likely cause for his dysphagia. Manometry revealed incomplete relaxation of the LOS in two patients and normal relaxation in one. Our experience suggests that failure of opening of the LOS may be observed as a transient finding of little clinical importance on upright double-contrast views of the oesophagus using high-density barium, with normal opening of the LOS on prone single-contrast views using low-density barium. It is important to be aware of this finding, so that it is not mistaken for achalasia or other abnormalities of the distal oesophagus.

Barrett esophagus: update for radiologists

Barrett esophagus is a well-recognized entity in which there is progressive columnar metaplasia of the lower esophagus due to longstanding gastroesophageal reflux and reflux esophagitis [1]. This condition is important because it is associated with an increased risk of developing esophageal adenocarcinoma by a well-established sequence from dysplasia to carcinoma [2]. During the past decade, however, an explosion of new data has dramatically affected our understanding of Barrett esophagus. Not only have revised histopathologic criteria been developed for this condition, but it is currently believed that patients with Barrett esophagus should be classified as having "short-segment" or "long-segment" disease based on the extent of columnar metaplasia in the distal esophagus. This distinction has important implications for the risk of developing esophageal adenocarcinoma and subsequent need for endoscopic surveillance. The purpose of this article is to present these new concepts about Barrett esophagus and provide radiologists with a more current framework for diagnosing this condition.

Laparoscopic Heller myotomy and fundoplication: findings and predictive value of early postoperative radiographic studies

BACKGROUND

We describe the findings on esophagography, the frequency and appearance of leaks after laparoscopic Heller myotomy and fundoplication, and the utility of early postoperative studies for predicting clinical outcome.

METHODS

Our study group consisted of 40 patients who underwent laparoscopic Heller myotomy and fundoplication in whom radiographic studies were performed during the early postoperative period. The radiographic reports and images were reviewed to determine the esophageal diameter, visualization or nonvisualization of the wrap, and the presence or absence of a leak. The esophageal diameter subsequently was correlated with the clinical findings to determine whether this was a useful parameter for predicting clinical outcome.

RESULTS

Two patients (5%) had small, sealed-off leaks on radiographic studies, and four (10%) had pseudo-leaks resulting from trapping of contrast material alongside the fundoplication wrap. Twelve (60%) of 20 patients with a dilated esophagus had esophageal symptoms on short-term follow-up versus three (15%) of 20 with a normal-caliber esophagus (p = 0.008), and five (56%) of nine patients with a dilated esophagus had symptoms on long-term follow-up versus six (43%) of 14 with a normal-caliber esophagus (p = 0.68).

CONCLUSION

Radiographic studies are useful for showing leaks after laparoscopic Heller myotomy and fundoplication, but radiologists should differentiate true leaks from trapping of contrast material alongside the fundoplication wrap. The caliber of the esophagus on early postoperative studies is also a useful parameter for predicting short-term clinical outcome in these patients.

Endogenous opioids mediate basal hedonic tone independent of dopamine D-1 or D-2 receptor activation

Exogenously administered opiates are recognized as rewarding and the involvement of dopamine systems in mediating their apparent pleasurable effects is contentious. The aversive response to naloxone administration observed in animal studies suggests the presence of an endogenous opioid tone regulating hedonic state. We sought evidence for the requirement for dopamine systems in mediating this action of endogenous opioids by determining whether mice deficient in dopamine D-1 or D-2 receptors were able to display conditioned place aversion to naloxone. Mice received saline in the morning in one chamber and either saline or naloxone (10 mg/kg, s.c.) in the afternoon in another chamber, each day for 3 days. On the test day they were given free access to the testing chambers in the afternoon. Similar to their wild-type littermates, D-1 and D-2 receptor knockout mice receiving naloxone in the afternoon spent significantly less time on the test day in the compartment in which they previously received naloxone, compared with animals receiving saline in the afternoon. The persistence of naloxone-conditioned place aversion in D-1 and D-2 knockout mice suggests that endogenous opioid peptides maintain a basal level of positive affect that is not dependent on downstream activation of dopamine systems involving D-1 or D-2 receptors.

Ionotropic Glutamate Receptor Expression and Dopaminergic Modulation in the Developing Subthalamic Nucleus of the Rat: An Immunohistochemical and Electrophysiological Analysis

Using standard immunohistochemical procedures, we investigated the changes in the expression of ionotropic glutamate receptor (GluR) subunits, GluRl, GluR5/6/7, and NMDAR1, in the subthalamic nucleus of developing rats. The general sequence of development for each subunit was the same. At early postnatal ages, there was dense neuropil staining and cellular clustering which progressed to decreased neuropil staining and an even distribution of conspicuous cells in the later postnatal ages and in the adult. GluR5/6/7 displayed the earliest maturation, while GluR1 exhibited the slowest maturation. These morphological changes suggest a different time course for the functionality of GluR subtypes in the developing subthalamic nucleus. Correlative electrophysiological studies demonstrated functional GluRs as early as 16 days of age. All neurons tested displayed robust responses to kainate and N-methyl-D-aspartate, and these responses were modulated by dopamine.

Detection of reflux esophagitis on double-contrast esophagrams and endoscopy using the histologic findings as the gold standard

The purpose of our study was to determine the accuracy of double-contrast barium studies and endoscopy for detecting reflux esophagitis, using the endoscopic biopsy findings as the gold standard. A review of radiology, endoscopy, and pathology files showed 37 patients with reflux symptoms who underwent double-contrast barium studies and endoscopy with biopsy specimens from the esophagus. The radiographic images were reviewed in a blinded fashion and correlated with the endoscopic and histologic findings to determine the radiographic and endoscopic accuracies for detecting reflux esophagitis, using the endoscopic biopsy specimens as the gold standard. Double-contrast barium studies and endoscopy had low but comparable accuracies for detecting reflux esophagitis, with sensitivities of 35% and 39%, specificities of 79% and 71%, positive predictive values of 73% and 69%, and negative predictive values of 42% and 41%, respectively. When mucosa granularity was evaluated as an individual sign of esophagitis on double-contrast studies, this finding had a sensitivity of 35%, a specificity of 93%, a positive predictive value of 89%, and a negative predictive value of 46% for detecting reflux esophagitis. Our experience suggests that double-contrast barium studies and endoscopy have limited ability to detect reflux esophagitis, in particular mild esophagitis, when using the histologic findings as the gold standard. When radiographic abnormalities are detected, however, mucosal granularity is the single best sign of reflux esophagitis on double-contrast studies.

Calcium modulates dopamine potentiation of N-methyl-D-aspartate Responses: Electrophysiological and imaging evidence

In the striatum, dopamine (DA) exerts a major modulatory influence on voltage- and ligand-gated currents. Previously we have shown that DA modulates glutamatergic neurotransmission and that the direction of this modulation depends on, among other factors, the glutamate and DA receptor subtypes activated. These effects also involve DA-induced alterations in voltage-gated Ca(2+) currents. In the present experiments, the effects of Ca(2+) channel blockers on DA and D1 receptor-dependent potentiation of N-methyl-D-aspartate (NMDA) responses were examined in vitro in striatal slices using current clamp recording techniques. DA or D1 receptor agonists consistently enhanced NMDA responses. Cadmium and the more selective L-type Ca(2+) channel antagonists nifedipine and methoxyverapamil reduced the potentiation of NMDA responses by DA or D1 receptor activation. Furthermore, studies using Ca(2+) imaging with Fluo-3 in cultured cortical or dissociated striatal neurons demonstrated that DA and D1 agonists increased intracellular Ca(2+) transients induced by NMDA. These as well as previous findings indicate that in striatal neurons at least two mechanisms contribute to the enhancement of NMDA responses by DA receptor activation, facilitation of voltage-gated Ca(2+) currents and D1 receptor activation of the cAMP-protein kinase A cascade. The existence of multiple mechanisms leading to a similar outcome allows a certain degree of redundancy in the consequences of DA modulation.

Radiographically diagnosed antral gastritis: findings in patients with and without Helicobacter pylori infection

The purpose of this study was to characterize the radiographic findings of antral gastritis and to determine whether there are differences in the appearance of antral gastritis in patients with and without Helicobacter pylori infection. A search of radiology, endoscopy and pathology files revealed 90 patients with antral gastritis on double contrast upper gastrointestinal tract studies who had endoscopy with testing for H. pylori. The barium studies were evaluated to further characterize the findings of antral gastritis without knowledge of the H. pylori status of the patients or of the endoscopy or pathology findings. The radiographic findings of antral gastritis included thickened folds in 67 patients (74%), polypoid antral gastritis (a subset of patients with thickened folds) in 6 (9%), antral erosions in 21 (23%), enlarged areae gastricae in 14 (16%), crenulation of the lesser curvature in 4 (4%), mucosal nodularity in 2 (2%), a hypertrophied antral-pyloric fold in 2 (2%) and antral striae in 1 (1%). 43 patients (48%) with antral gastritis were H. pylori positive and 47 patients (52%) were H. pylori negative. Thickened folds were detected in 39 H. pylori-positive patients (91%) with antral gastritis vs 28 H. pylori-negative patients (60%) (p<0.001); polypoid gastritis in 6 H. pylori-positive patients (14%) vs 0 H. pylori-negative patients (p<0.05); enlarged areae gastricae in 14 H. pylori-positive patients (33%) vs 0 H. pylori-negative patients (p<0.0001); and antral erosions in 2 H. pylori-positive patients (5%) vs 19 H. pylori-negative patients (40%) (p<0.0001). Our experience suggests that antral gastritis caused by H. pylori infection is associated with characteristic features on double contrast studies (including thickened folds, polypoid gastritis and enlarged areae gastricae) and that this condition is rarely associated with antral erosions. Thus, radiologists can often suggest whether the patient's gastritis is caused by H. pylori on the basis of radiographic findings.

Delayed postnatal development of NMDA receptor function in medium-sized neurons of the rat striatum

During early postnatal development, the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor plays a dominant role in excitatory amino acid-mediated synaptic transmission in essentially every brain region that has been examined. In contrast, we have found that in the rat striatum, NMDA receptor-mediated current develops later in the medium-sized neurons (MSNs) than currents mediated by activation of non-NMDA receptors. MSNs were identified using infrared video microscopy, and voltage-clamped in a slice preparation using the whole-cell patch-clamp technique. Intrastriatal stimulation was used to evoke excitatory synaptic currents from slices in animals ranging in age from postnatal day (PND) 5 to 60. Though most cells from animals younger than PND 10 failed to respond to synaptic stimulation, postsynaptic responses were occasionally evoked in cells as young as PND 5. Synaptic currents from cells between PNDs 5 and 7 had a significant contribution due to activation of non- NMDA receptors, as evidenced by sensitivity to the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione and rapidly rising and falling response components. The relative contribution of NMDA receptors increased approximately twofold from the first to the third postnatal week; no further change was observed through PND 60. At the same ages that the NMDA receptors contributed maximally to the synaptic current, the decay time constant of the NMDA receptor-mediated current decreased significantly. The increasing weight of NMDA receptor-mediated current may reflect a change in the number of functional receptors at the synapse since there was no apparent change in the voltage dependence of the current. To more completely examine receptor function early in postnatal development, NMDA and kainate were applied either iontophoretically or in the bath. Iontophoretic application of NMDA onto cells obtained from rats between PNDs 3 and 5 only occasionally evoked current, provided that the membrane was held at depolarized potentials to remove the Mg(2+) block. In contrast, application of kainate consistently evoked a response from cells of the same age group. Bath application of the same agonists provided similar results. Taken together, the present experiments demonstrate that striatal non-NMDA receptor-mediated currents are more mature than NMDA receptor-mediated currents early in development.

Electrophysiological and morphological changes in striatal spiny neurons in R6/2 Huntington's disease transgenic mice

We examined passive and active membrane properties and synaptic responses of medium-sized spiny striatal neurons in brain slices from presymptomatic (approximately 40 days of age) and symptomatic (approximately 90 days of age) R6/2 transgenics, a mouse model of Huntington's disease (HD) and their age-matched wild-type (WT) controls. This transgenic expresses exon 1 of the human HD gene with approximately 150 CAG repeats and displays a progressive behavioral phenotype associated with numerous neuronal alterations. Intracellular recordings were obtained using standard techniques from R6/2 and age-matched WT mice. Few electrophysiological changes occurred in striatal neurons from presymptomatic R6/2 mice. The changes in this age group were increased neuronal input resistance and lower stimulus intensity to evoke action potentials (rheobase). Symptomatic R6/2 mice exhibited numerous electrophysiological alterations, including depolarized resting membrane potentials, increased input resistances, decreased membrane time constants, and alterations in action potentials. Increased stimulus intensities were required to evoke excitatory postsynaptic potentials (EPSPs) in neurons from symptomatic R6/2 transgenics. These EPSPs had slower rise times and did not decay back to baseline by 45 ms, suggesting a more prominent component mediated by activation of N-methyl-D-aspartate receptors. Neurons from both pre- and symptomatic R6/2 mice exhibited reduced paired-pulse facilitation. Data from biocytin-filled or Golgi-impregnated neurons demonstrated decreased dendritic spine densities, smaller diameters of dendritic shafts, and smaller dendritic fields in symptomatic R6/2 mice. Taken together, these findings indicate that passive and active membrane and synaptic properties of medium-sized spiny neurons are altered in the R6/2 transgenic. These physiological and morphological alterations will affect communication in the basal ganglia circuitry. Furthermore, they suggest areas to target for pharmacotherapies to alleviate and reduce the symptoms of HD.

Changes in cortical and striatal neurons predict behavioral and electrophysiological abnormalities in a transgenic murine model of Huntington's disease

Neurons in Huntington's disease exhibit selective morphological and subcellular alterations in the striatum and cortex. The link between these neuronal changes and behavioral abnormalities is unclear. We investigated relationships between essential neuronal changes that predict motor impairment and possible involvement of the corticostriatal pathway in developing behavioral phenotypes. We therefore generated heterozygote mice expressing the N-terminal one-third of huntingtin with normal (CT18) or expanded (HD46, HD100) glutamine repeats. The HD mice exhibited motor deficits between 3 and 10 months. The age of onset depended on an expanded polyglutamine length; phenotype severity correlated with increasing age. Neuronal changes in the striatum (nuclear inclusions) preceded the onset of phenotype, whereas cortical changes, especially the accumulation of huntingtin in the nucleus and cytoplasm and the appearance of dysmorphic dendrites, predicted the onset and severity of behavioral deficits. Striatal neurons in the HD mice displayed altered responses to cortical stimulation and to activation by the excitotoxic agent NMDA. Application of NMDA increased intracellular Ca(2+) levels in HD100 neurons compared with wild-type neurons. Results suggest that motor deficits in Huntington's disease arise from cumulative morphological and physiological changes in neurons that impair corticostriatal circuitry.

NMDA receptor function in mouse models of Huntington disease

Huntington disease (HD) is an autosomal dominant disorder in which degeneration of medium-sized spiny striatal neurons occurs. The HD gene and the protein it encodes, huntingtin, have been identified but their functions remain unknown. Transgenic mouse models for HD have been developed and we examined responses of medium-sized striatal neurons recorded in vitro to application of N-methyl-D-aspartate (NMDA) in two of these. The first model (R6/2) expresses exon 1 of the human HD gene with approximately 150 CAG repeats. In the R6/2 an enhancement of currents induced by selective activation of NMDA receptors as well as an enhancement of intracellular Ca(2+) flux occurred in both presymptomatic and symptomatic mice. These alterations appeared specific for the NMDA receptor because alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor-mediated currents were reduced in symptomatic R6/2s. In R6/2 animals there were parallel increases in NMDA-R1 and decreases in NMDA-R2A/B subunit proteins as established by immunohistochemistry. The second model (YAC72) contains human genomic DNA spanning the full-length gene and all its regulatory elements with 72 CAG repeats. The phenotypical expression of the disorder develops more gradually than in the R6/2. In YAC72 mice we found similar but less marked increases in responses of medium-sized striatal neurons to NMDA. These findings indicate that alterations in NMDA receptor function may predispose striatal neurons to excitotoxic damage, leading to subsequent neuronal degeneration and underscore the functional importance of NMDA receptors in HD.

Radiographic findings and complications after surgical or endoscopic repair of Zenker's diverticulum in 16 patients

OBJECTIVE

The purpose of our study was to reassess the radiographic findings and complications associated with surgical or endoscopic repair of Zenker's diverticulum.

MATERIALS AND METHODS

Sixteen patients who underwent various procedures for repair of Zenker's diverticulum (diverticulectomy and cricopharyngeal myotomy in [n = 8], diverticulopexy and cricopharyngeal myotomy [n = 4], endoscopic stapling diverticulotomy [n = 3], and cricopharyngeal myotomy alone [n = 1]) had radiographic studies with water-soluble contrast material, barium, or both during the early postoperative period (n = 7), late postoperative period (n = 4), or both (n = 5). The radiologic reports and images were reviewed to determine the postoperative findings and complications associated with surgical or endoscopic repair of Zenker's diverticulum.

RESULTS

Radiographic studies revealed leaks during the early postoperative period in three (27%) of 11 patients after surgical repair of Zenker's diverticulum and in zero of three patients after endoscopic diverticulotomy. Pharyngeal dysfunction (pharyngeal paresis, decreased epiglottic tilt, laryngeal penetration, or tracheobronchial aspiration) was detected in seven (54%) of 13 patients after surgery and in one (33%) of three patients after endoscopic diverticulotomy; five of these eight patients had follow-up barium studies during the late postoperative period, and all five showed marked improvement in pharyngeal function. An extrinsic cricopharyngeal impression was detected in six (38%) of these 16 patients, a remnant diverticulum in four (25%), and mucosal beaking in three (19%). A suspended or inverted diverticulum was detected in one of the four patients who underwent surgical diverticulopexy.

CONCLUSION

Radiologists should be aware of the various postoperative findings and complications associated with surgical or endoscopic repair of Zenker's diverticulum so that appropriate interventions can be taken in patients with this condition.

Cervical esophageal webs: association with gastroesophageal reflux

BACKGROUND

We investigated whether there is a significant association between cervical esophageal webs and gastroesophageal reflux on pharyngoesophagography.

METHODS

We studied 50 patients with cervical esophageal webs on pharyngoesophagrams and 50 control subjects. The control group was matched to the webs group for age, sex, and symptomatology. Patients with cervical esophageal webs and controls were compared to determine the prevalence of gastroesophageal reflux, hiatal hernias, reflux esophagitis, and abnormal esophageal motility. Pearson's chi-square test was used to determine any statistically significant differences in the frequencies of these findings between groups.

RESULTS

Thirty-nine (78%) of 50 patients with cervical esophageal webs versus 27 (54%) of 50 patients in the control group had gastroesophageal reflux (p = 0.01). When patients were classified based on degree of gastroesophageal reflux, 22 (44%) of 50 patients with cervical esophageal webs versus 21 (42%) of 50 controls had mild reflux (p = 0.84), whereas 17 (34%) of 50 patients with webs versus six (12%) of 50 controls (p < 0.009) had moderate/marked reflux. Thus, the prevalence of moderate/marked gastroesophageal reflux was significantly greater in patients with webs than in the controls. However, no significant differences were found in the prevalence of mild gastroesophageal reflux, hiatal hernias, reflux esophagitis, or abnormal esophageal motility.

CONCLUSION

We found a significant association between cervical esophageal webs and gastroesophageal reflux independent of age, sex, or symptomatology. Radiologists should be aware of this association, so that patients with cervical esophageal webs on pharyngoesophagography are evaluated for gastroesophageal reflux at the time of the barium study or advised to undergo further testing for gastroesophageal reflux disease.

Differential sensitivity of medium- and large-sized striatal neurons to NMDA but not kainate receptor activation in the rat

Infrared videomicroscopy and differential interference contrast optics were used to identify medium- and large-sized neurons in striatal slices from young rats. Whole-cell patch-clamp recordings were obtained to compare membrane currents evoked by application of N-methyl-d-aspartate (NMDA) and kainate. Inward currents and current densities induced by NMDA were significantly smaller in large- than in medium-sized striatal neurons. The negative slope conductance for NMDA currents was greater in medium- than in large-sized neurons and more depolarization was required to remove the Mg2+ blockade. In contrast, currents induced by kainate were significantly greater in large-sized neurons whilst current densities were approximately equal in both cell types. Spontaneous excitatory postsynaptic currents occurred frequently in medium-sized neurons but were relatively infrequent in large-sized neurons. Excitatory postsynaptic currents evoked by electrical stimulation were smaller in large- than in medium-sized neurons. A final set of experiments assessed a functional consequence of the differential sensitivity of medium- and large-sized neurons to NMDA. Cell swelling was used to examine changes in somatic area in both neuronal types after prolonged application of NMDA or kainate. NMDA produced a time-dependent increase in somatic area in medium-sized neurons whilst it produced only minimal changes in large interneurons. In contrast, application of kainate produced significant swelling in both medium- and large-sized cells. We hypothesize that reduced sensitivity to NMDA may be due to variations in receptor subunit composition and/or the relative density of receptors in the two cell types. These findings help define the conditions that put neurons at risk for excitotoxic damage in neurological disorders.

Fecal impaction: a cause of isolated small bowel dilatation on abdominal radiographs

OBJECTIVE

The purpose of this study was to assess the frequency of isolated small bowel dilatation on abdominal radiographs in patients with colonic fecal impaction and also to elucidate the cause of this finding.

METHODS

A computerized search of radiology files revealed 515 patients with colonic fecal impaction on abdominal radiographs. The radiologic reports described isolated small bowel dilatation not related to other known causes of ileus or obstruction in 18 (3.5%) of the 515 patients. The films were reviewed to determine the distribution of fecal impaction and the degree and extent of small bowel dilatation. In 16 cases, medical records were reviewed to determine the clinical presentation, treatment, and course. Finally, follow-up radiographs were reviewed in four cases to determine the response to treatment of the impaction.

RESULTS

All 16 patients with available medical records had abdominal symptoms. The average diameter of the dilated small bowel on abdominal radiographs was 3.7 cm. Fourteen patients (78%) had a diffuse colonic fecal impaction (nine) or a predominantly right-sided fecal impaction (five) that involved the cecum, and the remaining four (22%) had a left-sided colonic fecal impaction. All 12 patients with clinical follow-up had resolution of symptoms and all four with follow-up radiographs had resolution of small bowel dilatation after treatment of the underlying impaction.

CONCLUSION

Fecal impaction should be considered in the differential diagnosis of small bowel dilatation on abdominal radiographs, as treatment of the underlying impaction usually produces a dramatic clinical response with resolution of the small bowel dilatation on follow-up radiographs.

Visualization of areae gastricae on double-contrast upper gastrointestinal radiography: relationship to age of patients

OBJECTIVE

The purpose of this study was to determine whether the frequency of visualization of areae gastricae on double-contrast upper gastrointestinal tract examinations is related to a patient's age.

MATERIALS AND METHODS

A total of 141 double-contrast upper gastrointestinal tract examinations with normal findings were reviewed for the presence or absence of areae gastricae on double-contrast images of the stomach. All images were evaluated by two radiologists who were blinded to the age of the patients. The data were then analyzed to determine if the frequency of visualization of areae gastricae on double-contrast studies was significantly related to the age of patients.

RESULTS

The frequency of visualization of areae gastricae increased significantly with increasing age (p = 0.008). The youngest age group (20--29 years old) exhibited areae gastricae in only four (19%) of 21 cases, whereas the oldest age group (> or = 70 years old) exhibited areae gastricae in 19 (76%) of 25 cases. On average, the rate of visualization of areae gastricae on double-contrast studies increased by 9% per decade.

CONCLUSION

Our data show that the frequency of visualization of areae gastricae on double-contrast upper gastrointestinal tract examinations increases significantly with increasing patient age. It is important for radiologists to be aware of the effect of aging on the delineation of areae gastricae on double-contrast studies.

Killian-Jamieson diverticula: radiographic findings in 16 patients

OBJECTIVE

The purpose of this study was to reassess the findings of Killian-Jamieson diverticula (i.e., proximal lateral cervical diverticula) on pharyngoesophagograms and to compare the prevalence, clinical findings, and radiographic findings of Killian-Jamieson diverticula with those of Zenker's diverticulum.

MATERIALS AND METHODS

A computerized search of radiology files revealed 16 patients with Killian-Jamieson diverticula and 26 patients with a Zenker's diverticulum. The double-contrast pharyngoesophagograms and medical records were reviewed retrospectively.

RESULTS

Only three (19%) of 16 patients with Killian-Jamieson diverticula had symptoms attributable to the diverticula (suprasternal dysphagia in two and cough in one), and none had aspiration pneumonia. In contrast, 16 (62%) of 26 patients with a Zenker's diverticulum had suprasternal dysphagia and three patients (12%) had aspiration pneumonia. Twenty Killian-Jamieson diverticula were detected on pharyngoesophagograms in 16 patients, including 12 (75%) with unilateral left-sided diverticula and four (25%) with bilateral diverticula. The Killian-Jamieson diverticula had an average maximal dimension of 1.4 cm. Zenker's diverticulum was nearly four times as common as Killian-Jamieson diverticula and had an average maximal dimension of 2.5 cm. Three patients (11%) with a Zenker's diverticulum had reflux of barium from the diverticula into the hypopharynx with overflow aspiration. Finally, gastroesophageal reflux was detected in nearly twice as many patients with a Zenker's diverticulum as with Killian-Jamieson diverticula.

CONCLUSION

Killian-Jamieson diverticula are less common and smaller than Zenker's diverticulum. Killian-Jamieson diverticula are less likely to cause symptoms and are less likely to be associated with overflow aspiration or gastroesophageal reflux than is Zenker's diverticulum.

Lymphoid hyperplasia of the stomach: radiographic findings in five adult patients

OBJECTIVE

The purpose of our study was to report the radiographic findings of biopsy-proven lymphoid hyperplasia of the stomach in five adult patients.

CONCLUSION

Lymphoid hyperplasia of the stomach is characterized by distinctive findings on double-contrast upper gastrointestinal tract barium examinations; all five patients had innumerable tiny (1--3 mm in diameter) round frequently umbilicated nodules that carpeted the mucosa of the gastric antrum or antrum and body. Three of these five patients had associated Helicobacter pylori gastritis. The diagnosis of gastric lymphoid hyperplasia, therefore, can be suggested on the basis of the radiographic findings.

Dopamine D4 receptor-deficient mice display cortical hyperexcitability

The dopamine D(4) receptor (D(4)R) is predominantly expressed in the frontal cortex (FC), a brain region that receives dense input from midbrain dopamine (DA) neurons and is associated with cognitive and emotional processes. However, the physiological significance of this dopamine receptor subtype has been difficult to explore because of the slow development of D(4)R agonists and antagonists the selectivity and efficacy of which have been rigorously demonstrated in vivo. We have attempted to overcome this limitation by taking a multidimensional approach to the characterization of mice completely deficient in this receptor subtype. Electrophysiological current and voltage-clamp recordings were performed in cortical pyramidal neurons from wild-type and D(4)R-deficient mice. The frequency of spontaneous synaptic activity and the frequency and duration of paroxysmal discharges induced by epileptogenic agents were increased in mutant mice. Enhanced synaptic activity was also observed in brain slices of wild-type mice incubated in the presence of the selective D(4)R antagonist PNU-101387G. Consistent with greater electrophysiological activity, nerve terminal glutamate density associated with asymmetrical synaptic contacts within layer VI of the motor cortex was reduced in mutant neurons. Taken together, these results suggest that the D(4)R can function as an inhibitory modulator of glutamate activity in the FC.

CtBP-dependent activities of the short-range Giant repressor in the Drosophila embryo

There are at least three short-range gap repressors in the precellular Drosophila embryo: Krüppel, Knirps, and Giant. Krüppel and Knirps contain related repression motifs, PxDLSxH and PxDLSxK, respectively, which mediate interactions with the dCtBP corepressor protein. Here, we present evidence that Giant might also interact with dCtBP. The misexpression of Giant in ventral regions of transgenic embryos results in the selective repression of eve stripe 5. A stripe5-lacZ transgene exhibits an abnormal staining pattern in dCtBP mutants that is consistent with attenuated repression by Giant. The analysis of Gal4-Giant fusion proteins identified a minimal repression domain that contains a sequence motif, VLDLS, which is conserved in at least two other sequence-specific repressors. Removal of this sequence from the native Giant protein does not impair its repression activity in transgenic embryos. We propose that Giant-dCtBP interactions might be indirect and mediated by an unknown bZIP subunit that forms a heteromeric complex with Giant. We also suggest that the VLDLS motif recruits an as yet unidentified corepressor protein.

Short-segment Barrett's esophagus: findings on double-contrast esophagography in 20 patients

OBJECTIVE

The purpose of this study was to determine the findings of short-segment Barrett's esophagus on double-contrast esophagography.

MATERIALS AND METHODS

A review of pathology and endoscopy data revealed 142 patients with short-segment Barrett's esophagus, which was defined as columnar epithelium in the distal esophagus extending 3 cm or less above the gastroesophageal junction at endoscopy with histopathologic confirmation of intestinal metaplasia. Twenty of these patients underwent double-contrast esophagography. These 20 patients comprised our study group. The original radiology reports and images were reviewed to determine the findings on double-contrast esophagography. Medical records were also reviewed to determine the clinical findings and treatment.

RESULTS

Double-contrast esophagrams revealed hiatal hernias in 18 patients (90%), gastroesophageal reflux in 16 (80%), reflux esophagitis in seven (35%), peptic scarring or strictures in 11 (55%), and a reticular mucosal pattern in none. A total of 14 patients (70%) had morphologic findings of reflux disease with esophagitis alone (three patients), peptic scarring or strictures alone (seven patients), or both (four patients), but the remaining six (30%) had hiatal hernias or gastroesophageal reflux as the only radiographic finding.

CONCLUSION

Double-contrast esophagography revealed morphologic findings of reflux disease with esophagitis, peptic scarring or strictures, or both in 70% of patients with short-segment Barrett's esophagus. Thus, the absence of esophagitis or peptic scarring or strictures on double-contrast esophagography does not exclude the possibility of short-segment Barrett's esophagus.

Congenital esophageal stenosis in adults: clinical and radiographic findings in seven patients

OBJECTIVE

The purpose of this study was to determine the clinical and radiographic findings in seven adults with congenital esophageal stenosis.

CONCLUSION

In young or middle-aged individuals, particularly men with long-standing dysphagia, an upper or mid esophageal stricture with multiple ringlike constrictions is a characteristic appearance of congenital esophageal stenosis on double-contrast esophagography.

Metabotropic glutamate receptors mGluR1alpha and mGluR2/3 display dynamic expression patterns in developing rat striatum

The developmental expression of two metabotropic glutamate receptors (mGluR), mGluR1alpha and mGluR2/3 was evaluated in the rat striatum from birth to adulthood. The mGluR1alpha receptor subtype displayed a patchy organization perinatally that became more homogeneous after the first postnatal week. The adult pattern of receptor expression consisted of homogeneous punctate profiles spread throughout the striatum. The mGluR2/3 receptor subtype exhibited a unique pattern of ontogenic expression, being associated exclusively with fibers of the internal capsule that penetrate the striatum, during the perinatal period. The protein localization for this subtype spread into the striatal neuropil after the first postnatal week, in parallel to the development of afferent terminations and arborizations to the nucleus. Unlike the ionotropic GluR subunits that are associated with somata and dendrites, neither subtype of metabotropic receptor was associated with neuronal cell bodies within the striatum.

Facilitated glutamatergic transmission in the striatum of D2 dopamine receptor-deficient mice

Dopamine (DA) receptors play an important role in the modulation of excitability and the responsiveness of neurons to activation of excitatory amino acid receptors in the striatum. In the present study, we utilized mice with genetic deletion of D2 or D4 DA receptors and their wild-type (WT) controls to examine if the absence of either receptor subtype affects striatal excitatory synaptic activity. Immunocytochemical analysis verified the absence of D2 or D4 protein expression in the striatum of receptor-deficient mutant animals. Sharp electrode current- and whole cell patch voltage-clamp recordings were obtained from slices of receptor-deficient and WT mice. Basic membrane properties were similar in D2 and D4 receptor-deficient mutants and their respective WT controls. In current-clamp recordings in WT animals, very little low-amplitude spontaneous synaptic activity was observed. The frequency of these spontaneous events was increased slightly in D2 receptor-deficient mice. In addition, large-amplitude depolarizations were observed in a subset of neurons from only the D2 receptor-deficient mutants. Bath application of the K+ channel blocker 4-aminopyridine (100 microM) and bicuculline methiodide (10 microM, to block synaptic activity due to activation of GABA(A) receptors) markedly increased spontaneous synaptic activity in receptor-deficient mutants and WTs. Under these conditions, D2 receptor-deficient mice displayed significantly more excitatory synaptic activity than their WT controls, while there was no difference between D4 receptor-deficient mice and their controls. In voltage-clamp recordings, there was an increase in frequency of spontaneous glutamate receptor-mediated inward currents without a change in mean amplitude in D2 receptor-deficient mutants. In WT mice, activation of D2 family receptors with quinpirole decreased spontaneous excitatory events and conversely sulpiride, a D2 receptor antagonist, increased activity. In D2 receptor-deficient mice, sulpiride had very little net effect. Morphologically, a subpopulation of medium-sized spiny neurons from D2 receptor-deficient mice displayed decreased dendritic spines compared with cells from WT mice. These results provide evidence that D2 receptors play an important role in the regulation of glutamate receptor-mediated activity in the corticostriatal or thalamostriatal pathway. These receptors may function as gatekeepers of glutamate release or of its subsequent effects and thus may protect striatal neurons from excessive excitation.

Portal hypertensive gastropathy: radiographic findings in eight patients

OBJECTIVE

The purpose of our study was to determine the findings of portal hypertensive gastropathy on barium studies in eight patients and whether there are useful radiographic criteria for diagnosing this condition.

CONCLUSION

Our experience suggests that portal hypertensive gastropathy may manifest on barium studies as thickened nodular folds in the gastric fundus. Although varices or various forms of gastritis can also produce thickened gastric folds, portal hypertensive gastropathy should be suspected when this finding is detected in patients with known portal hypertension.

CT findings in patients with esophagitis

OBJECTIVE

The purpose of our study was to determine the CT findings in patients with esophagitis.

MATERIALS AND METHODS

A search of medical and radiology files revealed 29 patients with esophagitis in whom thoracic CT was performed within 1 month of the diagnosis. The CT scans were reviewed retrospectively for esophageal wall thickening, a target sign, or other abnormalities. The thickness of the esophageal wall was also measured on CT in these 29 patients and compared with a control group of 85 patients.

RESULTS

We found that 16 patients (55%) with esophagitis had abnormal findings on CT, including a thickened esophageal wall (using 5 mm as the threshold for wall thickening) in all 16 (55%) and a target sign in five (17%). The overall mean esophageal wall thickness was 4.7 mm (standard deviation [SD], 2 mm; 95% confidence interval [CI], 0.7-8.7 mm) in patients with esophagitis versus a mean wall thickness of 2.9 mm (SD, 0.8 mm; 95% CI, 1.3-4.5 mm) in controls (p <.001). Using the same 5-mm threshold for wall thickening, we found that only three (4%) of 85 controls had a thickened esophageal wall on CT.

CONCLUSION

The majority of patients with esophagitis had abnormalities on CT, including a thickened esophageal wall (> or =5 mm) in 55% and a target sign in 17%. Although barium studies and endoscopy are more sensitive modalities for detecting this condition, the CT finding of a relatively long segment of circumferential esophageal wall thickening, with or without a target sign, should suggest the diagnosis of esophagitis in the proper clinical setting.

Giant hyperplastic polyps in the stomach: radiographic findings in seven patients

OBJECTIVE

We reassessed the radiographic findings of giant hyperplastic polyps in the stomach on double-contrast upper gastrointestinal examinations in seven patients.

CONCLUSION

Giant hyperplastic polyps in the stomach may be manifested by distinctive findings on double-contrast barium studies, appearing as polypoid lesions with multiple lobulated components that form a conglomerate mass. Nevertheless, endoscopy and biopsy are required to rule out a polypoid carcinoma as the cause of these findings.

Inactivation of Hdh in the brain and testis results in progressive neurodegeneration and sterility in mice

Inactivation of the mouse homologue of the Huntington disease gene (Hdh) results in early embryonic lethality. To investigate the normal function of Hdh in the adult and to evaluate current models for Huntington disease (HD), we have used the Cre/loxP site-specific recombination strategy to inactivate Hdh expression in the forebrain and testis, resulting in a progressive degenerative neuronal phenotype and sterility. On the basis of these results, we propose that huntingtin is required for neuronal function and survival in the brain and that a loss-of-function mechanism may contribute to HD pathogenesis.

Neurons recorded from pediatric epilepsy surgery patients with cortical dysplasia

PURPOSE

Cortical dysplasia (CD) is a common pathological substrate in patients with early-onset childhood epilepsy. In CD tissue, little is known about the mechanisms responsible for cellular hyperexcitability. In this study, we report initial electrophysiological and morphological observations from normal and dysmorphic cells in pediatric CD patients.

METHODS

Neocortical "most" and "least" epileptogenic areas were sampled based on neuroimaging and electrocorticography from 15 CD patients (ages 0.3 to 14 years). Whole-cell voltage clamp recordings combined with infrared videomicroscopy sampled abnormal cells (cytomegalic neurons, cells with bifurcated dendrites, disoriented pyramidal cells, etc.) compared with normal-appearing neurons from the same patient. Cells were filled with biocytin, and adjacent tissue blocks were stained for neuronal and glial markers.

RESULTS

About 15% of the 161 recorded cells were abnormal in appearance. Abnormal cells showed electrophysiological irregularities ranging from intrinsic cellular hyperexcitability to hyposensitivity after application of ionotropic receptor agonists. Other findings included increased excitatory postsynaptic currents and alterations in gamma-aminobutyric acid reversal potentials.

CONCLUSIONS

In pediatric CD tissue, these preliminary results indicate that abnormal-appearing cells showed abnormalities in electrophysiological measures compared with normal-appearing neurons. The abnormalities varied from hyperexcitability to hypoexcitability. More detailed results and conclusions will be forthcoming as additional patient material is analyzed.

Dopamine and N-methyl-D-aspartate receptor interactions in the neostriatum

This review examines dopamine (DA) and glutamate receptor interactions in the neostriatum (NS) primarily from a neurophysiological perspective. Historically, a clear understanding of the function of DA in the NS has been difficult because it was considered a classical neurotransmitter with either excitatory or inhibitory actions and because many of the data were obtained by use of varying methodologies. When DA is considered a neuromodulator whose role is to alter how NS cells respond to glutamatergic inputs, many of its actions can be accounted for and predicted with great accuracy within a model of receptor subtype. In this model, DA via activation of D1 receptors potentiates responses mediated by activation of N-methyl-D-aspartate (NMDA) receptors. DA via activation of D2 receptors attenuates responses mediated by activation of non-NMDA receptors. Outcomes of combinations of NMDA and D2 and non-NMDA and D1 receptors are not as predictable. The mechanisms underlying the D1-NMDA receptor interactions appear to involve alterations in cell excitability mediated by activation of Ca2+ conductances and/or phosphorylation of NMDA receptors. Less is known about mechanisms underlying the D2-non-NMDA receptor interaction. The functional implications of this model in setting membrane potentials, signal-to-noise ratio, plasticity and excitotoxicity are discussed.

Small flat umbilicated tumors of the colon: radiographic and pathologic findings

OBJECTIVE

We describe the radiographic and pathologic findings of small flat umbilicated tumors of the colon detected on double-contrast barium enema examinations performed in a Western population.

CONCLUSION

Unlike those reported by Japanese authors, the small flat umbilicated tumors of the colon in our patients were usually hyperplastic polyps, previously called "inverted hyperplastic polyps." Nevertheless, colonoscopy with excisional biopsy is warranted for such tumors detected on double-contrast barium enema examinations because of the small possibility that these tumors represent adenoma or even early adenocarcinoma.

Adynamic ileus after caesarean section mimicking intestinal obstruction: findings on abdominal radiographs

The purpose of this study was to determine the spectrum of findings and the frequency of apparent distal colonic obstruction on abdominal radiographs in women with obstructive symptoms following Caesarean section. A search of radiology files yielded 21 patients who had abdominal radiographs because of obstructive symptoms during the early post-operative period. The radiographs were reviewed retrospectively to characterize the bowel gas patterns in these patients. Medical records were also reviewed to determine the treatment and patient course. Abdominal radiographs showed findings suggestive of distal colonic obstruction in 15 patients (71%), small bowel obstruction in 2 (10%), adynamic ileus in 3 (14%) and a normal bowel gas pattern in 1 (5%). In all 15 patients with apparent distal colonic obstruction, there was minimal or no gas in the rectosigmoid, with an associated pelvic mass representing the enlarged post-partum uterus, which compressed the rectosigmoid and prevented it from filling with gas. All 21 patients had rapid clinical or radiographic improvement on conservative management, indicating a transient post-operative ileus. Radiologists should be aware of the limitations of abdominal plain radiographs following Caesarean section so that a post-operative ileus is not mistaken for a distal colonic obstruction and conservative measures can be undertaken to decompress the bowel until the ileus resolves.

Combined dietary and exercise intervention for control of serum cholesterol in the workplace

PURPOSE

To elucidate a potential combined dietary and exercise intervention affect on cardiovascular risk reduction of the National Aeronautics and Space Administration Headquarters employees.

DESIGN

A nonexperimental, longitudinal, clinical-chart review study (1987 to 1996) of an identified intervention group and a reference (not a control) group.

SETTING

The study group worked in an office environment and participated in the annual medical examinations.

SUBJECTS

An intervention group of 858 people with initially elevated serum cholesterol, and a reference group of 963 people randomly sampled from 10% of the study group.

MEASURES

Serum cholesterol data were obtained for both groups, respectively, from pre- and postintervention and annual examinations. The reference group was adjusted by statistical exclusion of potential intervention participants. Regression equations (cholesterol vs. study years) for the unadjusted/adjusted reference groups were tested for statistical significance.

INTERVENTION

An 8-week individualized, combined dietary and exercise program was instituted with annual follow-ups and was repeated where warranted.

RESULTS

Only the unadjusted (but not the adjusted) reference group with initial mean total serum cholesterol levels above 200 mg/dL shows a significant 9-year decline trend and significant beta coefficient tests. An intervention effect is suggested. Mean high density lipoprotein cholesterol rose slightly in the intervention group but was maintained in the reference group.

CONCLUSION

With potential design limitations, the NASA intervention program focusing on a high risk group may be associated to some degree, if not fully, with an overall cardiovascular risk profile improvement.

Diagnosis of primary versus secondary achalasia: reassessment of clinical and radiographic criteria

OBJECTIVE

Our purpose was to reassess the usefulness of barium studies and various clinical parameters for differentiating primary from secondary achalasia.

MATERIALS AND METHODS

Radiology files from 1989 through 1999 revealed 29 patients with primary achalasia and 10 with secondary achalasia (caused by carcinoma of the esophagus in three, of the gastric cardia in three, of the lung in three, and of the uterus in one) who met our study criteria. The radiographs were reviewed to determine the morphologic features of the narrowed distal esophageal segment and gastric cardia and fundus. Medical records were also reviewed to determine the clinical presentation; endoscopic, manometric, and surgical findings; and treatment.

RESULTS

The mean patient age was 53 years in primary achalasia versus 69 years in secondary achalasia (p = 0.03). The mean duration of dysphagia was 4.5 years in primary achalasia versus 1.9 months in secondary achalasia (p <0.0001). The narrowed distal esophageal segment had a mean length of 1.9 cm in primary achalasia versus 4.4 cm in secondary achalasia (p < 0.0001), and the esophagus had a mean diameter of 6.2 cm in primary achalasia versus 4.1 cm in secondary achalasia (p <0.0001). The narrowed segment was eccentric or nodular or had abrupt proximal borders in only four of 10 patients with secondary achalasia, and evidence of tumor was present in the gastric fundus in only three.

CONCLUSION

When findings of achalasia are present on barium studies, a narrowed distal esophageal segment longer than 3.5 cm with little or no proximal dilatation in a patient with recent onset of dysphagia should be considered highly suggestive of secondary achalasia, even in the absence of other suspicious radiographic findings.