The Accuracy of Colorectal Cancer Detection by Computed Tomography in the Unprepared Large Bowel in a Community-Based Hospital.

PURPOSE: This retrospective study examined the performance of general radiologists in a community-based hospital in detecting colorectal cancer (CRC) with computed tomography (CT) in the unprepared large bowel. METHODS: The pathology database at a community hospital over the past 7 years (2009-2015) was retrospectively analysed for pathologically proven CRC (924 cases). The provincial hospital information profile for these patients was reviewed to determine if they had an abdominal CT for any reason in the year prior to biopsy. Metrics such as age, sex, time between the CT and biopsy or surgery, whether CRC was initially detected by the radiologist, and if this was an emergency presentation was evaluated. In the cases where CRC was not identified, the CT scans were reanalysed to determine if the CRC was identifiable in retrospect. The sensitivity of detecting CRC by CT scan in the unprepared large bowel was calculated. RESULTS: Of the 924 biopsy proven CRC cases, 22% (207 of 924) of the patients had a CT prior to biopsy. Of these cases, 47% (97 of 207) presented on an emergency basis. Of the cases with imaging in the year prior, about 60% (125 of 207) had cancer prospectively detected by the radiologist. Upon re-examination of the cases in which CRC was not initially detected, 59% were visualized in retrospect. CONCLUSIONS: Community general radiologists can successfully detect CRC with a high degree of accuracy. Reformatted images, bowel wall thickening when regional nodes are prominent, and minimizing oral contrast were helpful in improving detection.

Post-vaccination myositis and myocarditis in a previously healthy male.

BACKGROUND: The immunological literature has been redefining clinical phenomena as hypotheses emerge regarding causal links between triggers, immunologic manifestations, and their specific inflammatory cascades. Of late, autoimmune manifestations that appear to be caused by an external adjuvant have been grouped into a complex syndrome referred to as autoimmune/inflammatory syndrome induced by adjuvants (ASIA). This syndrome may present with diverse clinical problems, which may include neurocognitive impairment, inflammatory musculoskeletal changes, and constitutional symptoms. There is evidence in the literature linking vaccines to different auto-immune manifestations. Vaccines have not traditionally been reported to trigger ASIA, although reports are emerging linking the human papilloma virus and hepatitis B vaccines to it. CASE PRESENTATION: We report the first suspected case of ASIA in a previously healthy patient who received the Fluad seasonal influenza vaccine, which contains the MF59 adjuvant. He presented to hospital with profound weakness and was diagnosed with severe rhabdomyolysis. He also had elevated troponin-I and extensive cardiac investigations enabled the diagnosis of myocarditis. His infectious and rheumatologic work-ups were negative. He responded well to conservative management and did not require immune suppressive therapy. CONCLUSION: Given the benefits of the influenza vaccine, and the low incidence of clinically significant complications, we encourage ongoing seasonal influenza immunization. However, ongoing surveillance is required to evaluate the occurrence of rare adverse events, including ASIA.

Pancreatic and Extrapancreatic Features in Autoimmune Pancreatitis.

Autoimmune pancreatitis (AIP) accounts for approximately 5% of chronic pancreatitis cases and is an important consideration in the differential diagnosis of pancreatic pathologies. The underlying pathophysiology of AIP is thought to involve lymphocyte infiltration and associated sclerosis. Although AIP is a benign condition that is treatable with corticosteroids, it can have imaging and clinical findings indistinguishable from pancreatic cancer. As such, the radiologist plays an important management role in distinguishing AIP from more sinister conditions. In addition, there are several extrapancreatic imaging findings in the context of AIP that have been recently described. This pictorial review outlines both the pancreatic and extrapancreatic imaging features in AIP and the response to steroid therapy. Important imaging features that allow AIP to be differentiated from other pancreatic pathology, including adenocarcinoma, lymphoma, and acute pancreatitis will be discussed.

Cerebral ischemic injury is enhanced in a model of oculodentodigital dysplasia.

Oculodentodigital dysplasia (ODDD) is a rare autosomal dominant disease that results in visible developmental anomalies of the limbs, face, eyes and teeth. Recently analysis of human connexin43 (Cx43) DNA sequences has revealed a number of different missense, duplication and frame shift mutations resulting in this phenotype. A mouse model of this disorder has been created with a missense point mutation of the glycine amino acid at position 60 to serine (G60S). Heterozygote +/G60S mice exhibit a similar ODDD phenotype as observed in humans. In addition to the malformations listed above, ODDD patients often have neurological findings. In the brain, Cx43 is highly expressed in astrocytes and has been shown to play a role in neuroprotection. We were interested in determining the effect of the +/G60S mutation following stroke. Four days after middle cerebral artery occlusion the volume of infarct was larger in mice with the +/G60S mutation. In astrocyte-neuron co-cultures, exposure to glutamate also resulted in greater cellular death in the +/G60S mutants. Protein levels of Cx43 in the mutant mouse were found to be reduced when compared to the normal tissue. Cx43 protein was observed as a continual line of small punctate aggregates in the plasma membrane with increased intracellular localization, which is distinct from the larger plaques seen in the normal mouse astrocytes. Functionally, primary +/G60S astrocytes exhibited reduced gap junctional coupling and increased hemichannel activity, which may underlie the mechanism of increased damage during stroke. This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'.

Inhibition of cytokine-induced connexin43 hemichannel activity in astrocytes is neuroprotective.

Astrocytes express high levels of connexin43, a protein that forms two types of channels: gap junction channels for direct intercellular communication, and hemichannels for exchanges with the extracellular space. Inflammation induces connexin43 hemichannel activation, which has been proposed to be involved in neuroglial interactions. Here, we investigated the contribution of connexin43 to NMDA-induced excitotoxicity in neuron/astrocyte co-cultures, after treatment with a pro-inflammatory cytokine mixture, containing TNF-alpha and IL1-beta (Mix), that stimulated astroglial connexin43 hemichannel activity. Interestingly, NMDA treatment induced a higher amount of neurotoxicity in Mix-treated co-cultures than in untreated ones, whereas this extent of neurotoxicity was absent in enriched neuron cultures or in co-cultures with connexin43 knock-out astrocytes. Furthermore, application of connexin43 hemichannel blockers or a synthetic cannabinoid prevented the Mix-induced potentiated NMDA neurotoxicity. Altogether, these data demonstrate that inflammation-induced astroglial hemichannel activation plays a critical role in neuronal death and suggest a neuroprotective role of connexin43 hemichannel blockade.

Temporary sequestration of potassium by mitochondria in astrocytes.

Increases in extracellular potassium concentration ([K(+)](o)), which can occur during neuronal activity and under pathological conditions such as ischemia, lead to a variety of potentially detrimental effects on neuronal function. Although astrocytes are known to contribute to the clearance of excess K(+)(o), the mechanisms are not fully understood. We examined the potential role of mitochondria in sequestering K(+) in astrocytes. Astrocytes were loaded with the fluorescent K(+) indicator PBFI and release of K(+) from mitochondria into the cytoplasm was examined after uncoupling the mitochondrial membrane potential with carbonyl cyanide m-chlorophenylhydrazone (CCCP). Under the experimental conditions employed, transient applications of elevated [K(+)](o) led to increases in K(+) within mitochondria, as assessed by increases in the magnitudes of cytoplasmic [K(+)] ([K(+)](i)) transients evoked by brief exposures to CCCP. When mitochondrial K(+) sequestration was impaired by prolonged application of CCCP, there was a robust increase in [K(+)](i) upon exposure to elevated [K(+)](o). Blockade of plasmalemmal K(+) uptake routes by ouabain, Ba(2+), or a mixture of voltage-activated K(+) channel inhibitors reduced K(+) uptake into mitochondria. Also, reductions in mitochondrial K(+) uptake occurred in the presence of mito-K(ATP) channel inhibitors. Rises in [K(+)](i) evoked by brief applications of CCCP following exposure to high [K(+)](o) were also reduced by gap junction blockers and in astrocytes isolated from connexin43-null mice, suggesting that connexins also play a role in K(+) uptake into astrocyte mitochondria. We conclude that mitochondria play a key role in K(+)(o) handling by astrocytes.

The connexin43 C-terminal region mediates neuroprotection during stroke.

Connexin43 plays an important role in neuroprotection in experimental stroke models; reducing the expression of this gap junction protein in astrocytes enhances injury upon middle cerebral artery occlusion (MCAO). Because the C-terminal region of connexin43 isimportant for channel activity, we carried out MCAO stroke experiments in mice expressing a truncated form of connexin43 (Cx43DeltaCT mice). Brain sections were analyzed for infarct volume, astrogliosis, and inflammatory cell invasion 4 days after MCAO. Adult cortices and astrocyte cultures were examined for connexin43 (Cx43) expression by immunohistochemistry and Western blot. Cultured astrocytes were also examined for dye coupling, channel conductance, hemichannel activity, and Ca wave propagation. The Cx43DeltaCT mice exhibit enhanced cerebral injury after stroke. Astrogliosis was reduced and inflammatory cell invasion was increased inthe peri-infarct region in these mice compared with controls; Cx43 expression was also altered. Lastly, cultured astrocytes from Cx43DeltaCT mice were less coupled and displayed alterations in channel gating, hemichannel activity, and Ca wave properties. These results suggest that astrocytic Cx43 contributed to the regulation of cell death after stroke and support the view that the Cx43 C-terminal region is important in protection in cerebral ischemia.

Galanin modulates neuronal and synaptic properties in the rat supraoptic nucleus in a use and state dependent manner.

The magnocellular neurons of the hypothalamic supraoptic nucleus (SON) synthesize and secrete oxytocin (OXT) and vasopressin (AVP) from their dendrites. These peptides, and several other neurotransmitters, have been shown to modulate afferent glutamatergic neurotransmission in the SON. The neuropeptide, galanin (GAL) is also localized in SON magnocellular neurons and in afferent fibers in the nucleus. We show that GAL dose-dependently reduces evoked excitatory postsynaptic currents (eEPSCs), alters paired pulse ratio and decreases mEPSC frequency, but not amplitude or decay kinetics in both OXT and AVP neurons. GAL therefore modulates excitatory neurotransmission at a likely presynaptic receptor. Neither OXT/AVP, GABA(B) nor cannabinoid antagonists blocked this effect. A GAL2/3 agonist mimicked GAL's action while GAL1 antagonist did not block GAL's effect, suggesting that GAL2/3 receptors mediate the presynaptic effect. In nondehydrated rats GAL causes a small postsynaptic response, as assessed by input resistance measurements. When the rats were water deprived for 2 days the presynaptic response to GAL was unaltered; however, the postsynaptic decrease in input resistance and hyperpolarization was increased, an effect consistent with a previously described increase in GAL1 receptor expression in dehydration. A GAL1 receptor antagonist blocked the postsynaptic effects. Last, when a train of eEPSCs was elicited, GAL was found to inhibit the earlier events in a train but not the latter. This indicates that GAL may modulate a single synaptic event more effectively than trains of synaptic inputs, thereby acting as a high-pass filter.

Vasopressin differentially modulates non-NMDA receptors in vasopressin and oxytocin neurons in the supraoptic nucleus.

Magnocellular neurons of the supraoptic nucleus release the neuropeptides oxytocin and vasopressin from their dendrites to regulate their synaptic inputs. This study aims to determine the cellular mechanism by which vasopressin modulates excitatory synaptic transmission. Presumably by electroporation through perforated patch, we were able to successfully introduce biocytin into cells in which we performed an electrophysiological study. This method enabled us to determine that roughly half of the recorded neurons were immunoreactive to oxytocin-associated neurophysin and showed two characteristic features: an inward rectification and a sustained outward rectification. The remaining half showed a linear voltage-current relationship and was immunoreactive to vasopressin-associated neurophysin. Using these electrophysiological characteristics and post hoc immunohistochemistry to identify vasopressin or oxytocin neurons, we found that vasopressin decreased evoked EPSCs in vasopressin neurons while increasing EPSCs in oxytocin neurons. In both types of neurons, EPSC decay constants were not affected, indicating that desensitization of non-NMDA receptors did not underlie the EPSC amplitude change. In vasopressin neurons, both vasopressin and a V1a receptor agonist, F-180, decreased AMPA-induced currents, an effect blocked by a V1a receptor antagonist SR49059. In oxytocin neurons, AMPA-induced currents were facilitated by vasopressin, whereas F-180 had no effect. An oxytocin receptor antagonist blocked the facilitatory effect of vasopressin. Thus, we conclude that vasopressin inhibits EPSCs in vasopressin neurons via postsynaptic V1a receptors, whereas it facilitates EPSCs in oxytocin neurons through oxytocin receptors.