Low-dose radiation decreases Lrrk2 levels in the striatum of large mammalian brains: New venues to treat Parkinson's disease?

INTRODUCTION: Among gene mutations and variants linked to an increased risk of PD, mutations of leucine-rich repeat kinase 2 gene (LRRK2) are among the most frequently associated with early- and late-onset PD. Clinical and neuropathological characteristics of idiopathic-PD (iPD) and LRRK2-PD are similar, and these similarities suggest that the pathomechanisms between these two conditions are shared. LRRK2 mutations determine a gain-of-function and yield higher levels of lrrk2 across body tissues, including brain. On another side, recent animal studies supported the potential use of low dose radiation (LDR) to modify the pathomechanisms of diseases such as Alzheimer's disease (AD). METHODS: We assessed if a single total-body LDR (sLDR) exposure in normal swine could alter expression levels of the following PD-associated molecules: alpha-synuclein (α-syn), phosphorylated-α-synuclein (pα-syn), parkin, tyrosine hydroxylase (th), lrrk2, phosphorylated-lrrk2 (pS935-lrrk2), and some LRRK2 substrates (Rab8a, Rab12) across different brain regions. These proteins were measured in frontal cortex, hippocampus, striatum, thalamus/hypothalamus, and cerebellum of 9 radiated (RAD) vs. 6 sham (SH) swine after 28 days from a sLDR of 1.79Gy exposure. RESULTS: Western Blot analyses showed lowered lrrk2 levels in the striatum of RAD vs. SH swine (p < 0.05), with no differences across the remaining brain regions. None of the other protein levels differed between RAD and SH swine in any examined brain regions. No lrrk2 and p-lrrk2 (S935) levels differed in the lungs of RAD vs. SH swine. CONCLUSIONS: These findings show a specific striatal lrrk2 lowering effect due to LDR and support the potential use of LDR to interfere with the pathomechanisms of PD.

Chronic traumatic encephalopathy pathognomonic lesions occurring in isolation adjacent to infiltrative and non-infiltrative white matter lesions.

Chronic traumatic encephalopathy (CTE) is defined by perivascular neuronal phosphorylated-tau accumulation at cortical sulcal depths. CTE has been mainly described in the context of repetitive, impact-type traumatic brain injury (rTBI), principally from contact sports. Rarely, CTE has been associated with single TBIs, including in relationship to healed leucotomy sites in brains from formerly institutionalized psychiatric patients without documented rTBI. Given that leucotomy principally involves severing of white matter, this could suggest involvement of axonal injury in CTE pathophysiology. We present three cases wherein isolated CTE pathology was identified adjacent to distinct white matter lesions. Case 1 is a 41-year-old man with history of hereditary hemorrhagic telangiectasia and resection of a cerebral arteriovenous malformation (AVM). Case 2 is a 46-year-old man with glioblastoma. Case 3 is a 52-year-old man with a remote cerebral infarct. Isolated CTE lesions were found adjacent to the aforementioned pathologies in each case. Additional CTE lesions were not identified despite extensive sampling. Multiple age-related tau astrogliopathy (ARTAG)-like lesions were also identified at other sulcal depths near the AVM resection site in Case 1. These cases may provide insights regarding the pathophysiology of the CTE pathognomonic lesion and the development of ARTAG-like pathology adjacent to long-standing mass lesions.

Proteomic changes in the hippocampus of large mammals after total-body low dose radiation.

There is a growing interest in low dose radiation (LDR) to counteract neurodegeneration. However, LDR effects on normal brain have not been completely explored yet. Recent analyses showed that LDR exposure to normal brain tissue causes expression level changes of different proteins including neurodegeneration-associated proteins. We assessed the proteomic changes occurring in radiated vs. sham normal swine brains. Due to its involvement in various neurodegenerative processes, including those associated with cognitive changes after high dose radiation exposure, we focused on the hippocampus first. We observed significant proteomic changes in the hippocampus of radiated vs. sham swine after LDR (1.79Gy). Mass spectrometry results showed 190 up-regulated and 120 down-regulated proteins after LDR. Western blotting analyses confirmed increased levels of TPM1, TPM4, PCP4 and NPY (all proteins decreased in various neurodegenerative processes, with NPY and PCP4 known to be neuroprotective) in radiated vs. sham swine. These data support the use of LDR as a potential beneficial tool to interfere with neurodegenerative processes and perhaps other brain-related disorders, including behavioral disorders.

Brain tumors in United States military veterans.

BACKGROUND: Comprehensive analysis of brain tumor incidence and survival in the Veteran population has been lacking. METHODS: Veteran data were obtained from the Veterans Health Administration (VHA) Medical Centers via VHA Corporate Data Warehouse. Brain tumor statistics on the overall US population were generated from the Central Brain Tumor Registry of the US data. Cases were individuals (≥18 years) with a primary brain tumor, diagnosed between 2004 and 2018. The average annual age-adjusted incidence rates (AAIR) and 95% confidence intervals were estimated per 100 000 population and Kaplan-Meier survival curves evaluated overall survival outcomes among Veterans. RESULTS: The Veteran population was primarily white (78%), male (93%), and between 60 and 64 years old (18%). Individuals with a primary brain tumor in the general US population were mainly female (59%) and between 18 and 49 years old (28%). The overall AAIR of primary brain tumors from 2004 to 2018 within the Veterans Affairs cancer registry was 11.6. Nonmalignant tumors were more common than malignant tumors (AAIR:7.19 vs 4.42). The most diagnosed tumors in Veterans were nonmalignant pituitary tumors (AAIR:2.96), nonmalignant meningioma (AAIR:2.62), and glioblastoma (AAIR:1.96). In the Veteran population, survival outcomes became worse with age and were lowest among individuals diagnosed with glioblastoma. CONCLUSIONS: Differences between Veteran and US populations can be broadly attributed to demographic composition differences of these groups. Prior to this, there have been no reports on national-level incidence rates and survival outcomes for Veterans. These data provide vital information that can drive efforts to understand disease burden and improve outcomes for individuals with primary brain tumors.

Low-dose brain radiation: lowering hyperphosphorylated-tau without increasing DNA damage or oncogenic activation.

Brain radiation has been medically used to alter the metabolism of cancerous cells and induce their elimination. Rarely, though, brain radiation has been used to interfere with the pathomechanisms of non-cancerous brain disorders, especially neurodegenerative disorders. Data from low-dose radiation (LDR) on swine brains demonstrated reduced levels of phosphorylated-tau (CP13) and amyloid precursor protein (APP) in radiated (RAD) versus sham (SH) animals. Phosphorylated-tau and APP are involved in Alzheimer's disease (AD) pathogenesis. We determined if the expression levels of hyperphosphorylated-tau, 3R-tau, 4R-tau, synaptic, intraneuronal damage, and DNA damage/oncogenic activation markers were altered in RAD versus SH swine brains. Quantitative analyses demonstrated reduced levels of AT8 and 3R-tau in hippocampus (H) and striatum (Str), increased levels of synaptophysin and PSD-95 in frontal cortex (FCtx), and reduced levels of NF-L in cerebellum (CRB) of RAD versus SH swine. DNA damage and oncogene activation markers levels did not differ between RAD and SH animals, except for histone-H3 (increased in FCtx and CRB, decreased in Str), and p53 (reduced in FCtx, Str, H and CRB). These findings confirm the region-based effects of sLDR on proteins normally expressed in larger mammalian brains and support the potential applicability of LDR to beneficially interfere against neurodegenerative mechanisms.

Alpha-methyltyrosine reduces the acute cardiovascular and behavioral sequelae in a murine model of traumatic brain injury.

BACKGROUND: Increased catecholamines contribute to heightened cardiovascular reactivity and behavioral deficits after traumatic brain injury (TBI); adrenergic receptor blockade has limited success in reducing adverse sequelae of TBI. Injury-induced increases in the synthesis of catecholamines could contribute to adverse outcomes in TBI. Inhibition of catecholamine synthesis with alpha-methyltyrosine (αMT) could offer a benefit after TBI. METHODS: Original research trial in mice randomized to αMT (50 mg·kg -1 ·d -1 ) or vehicle for 1 week after TBI induced by controlled cortical impact. Primary outcomes of cardiovascular reactivity and behavioral deficits were assessed after 1 week. Secondary outcomes included blood brain barrier permeability and quantification of gene transcription whose products determine intraneuronal chloride concentrations, the release of catecholamines, and activation of the sympathetic nervous system. These genes were the alpha-2 adrenergic receptor ("Adra2c"), the sodium-potassium-chloride cotransporter ("Nkcc1"), and the potassium chloride cotransporter ("Kcc2"). We also assessed the effect of TBI and αMT on the neuronal chloride/bicarbonate exchanger ("Ae3"). RESULTS: Traumatic brain injury-induced increases in blood pressure and cardiac reactivity were blocked by αMT. Inhibition of catecholamine synthesis decreased blood brain barrier leakage and improved behavioral outcomes after TBI. Traumatic brain injury diminished the transcription of Adra2c and enhanced expression of Nkcc1 while reducing Kcc2 transcription; αMT prevented the induction of the Nkcc1 by TBI without reversing the effects of TBI on Kcc2 expression; αMT also diminished Ae3 transcription. CONCLUSION: Traumatic brain injury acutely increases cardiovascular reactivity and induces behavioral deficits in an αMT-sensitive manner, most likely by inducing Nkcc1 gene transcription. Alpha-methyltyrosine may prove salutary in the treatment of TBI by attenuating the enhanced expression of Nkcc1, minimizing blood brain barrier leakage, and diminishing central catecholamine and sympathetic output. We also found an unreported relationship between Kcc2 and the chloride/bicarbonate exchanger, which should be considered in the design of trials planned to manipulate central intraneuronal chloride concentrations following acute brain injury.

Aß Deposits in the Neocortex of Adult and Infant Hypoxic Brains, Including in Cases of COVID-19.

The brain of a 58-year-old woman was included as a civilian control in an ongoing autopsy study of military traumatic brain injury (TBI). The woman died due to a polysubstance drug overdose, with Coronavirus Disease 2019 (COVID-19) serving as a contributing factor. Immunohistochemical stains for ß-amyloid (Aß), routinely performed for the TBI study, revealed numerous, unusual neocortical Aß deposits. We investigated the autopsied brains of 10 additional young patients (<60 years old) who died of COVID-19, and found similar Aß deposits in all, using two different Aß antibodies across three different medical centers. The deposits failed to stain with Thioflavin-S. To investigate whether or not these deposits formed uniquely to COVID-19, we applied Aß immunostains to the autopsied brains of COVID-19-negative adults who died with acute respiratory distress syndrome and infants with severe cardiac anomalies, and also biopsy samples from patients with subacute cerebral infarcts. Cortical Aß deposits were also found in these cases, suggesting a link to hypoxia. The fate of these deposits and their effects on function are unknown, but it is possible that they contribute to the neurocognitive sequelae observed in some COVID-19 patients. Our findings may also have broader implications concerning hypoxia and its role in Aß deposition in the brain.

Mild respiratory COVID can cause multi-lineage neural cell and myelin dysregulation.

COVID survivors frequently experience lingering neurological symptoms that resemble cancer-therapy-related cognitive impairment, a syndrome for which white matter microglial reactivity and consequent neural dysregulation is central. Here, we explored the neurobiological effects of respiratory SARS-CoV-2 infection and found white-matter-selective microglial reactivity in mice and humans. Following mild respiratory COVID in mice, persistently impaired hippocampal neurogenesis, decreased oligodendrocytes, and myelin loss were evident together with elevated CSF cytokines/chemokines including CCL11. Systemic CCL11 administration specifically caused hippocampal microglial reactivity and impaired neurogenesis. Concordantly, humans with lasting cognitive symptoms post-COVID exhibit elevated CCL11 levels. Compared with SARS-CoV-2, mild respiratory influenza in mice caused similar patterns of white-matter-selective microglial reactivity, oligodendrocyte loss, impaired neurogenesis, and elevated CCL11 at early time points, but after influenza, only elevated CCL11 and hippocampal pathology persisted. These findings illustrate similar neuropathophysiology after cancer therapy and respiratory SARS-CoV-2 infection which may contribute to cognitive impairment following even mild COVID.

Mild respiratory SARS-CoV-2 infection can cause multi-lineage cellular dysregulation and myelin loss in the brain.

Survivors of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection frequently experience lingering neurological symptoms, including impairment in attention, concentration, speed of information processing and memory. This long-COVID cognitive syndrome shares many features with the syndrome of cancer therapy-related cognitive impairment (CRCI). Neuroinflammation, particularly microglial reactivity and consequent dysregulation of hippocampal neurogenesis and oligodendrocyte lineage cells, is central to CRCI. We hypothesized that similar cellular mechanisms may contribute to the persistent neurological symptoms associated with even mild SARS-CoV-2 respiratory infection. Here, we explored neuroinflammation caused by mild respiratory SARS-CoV-2 infection - without neuroinvasion - and effects on hippocampal neurogenesis and the oligodendroglial lineage. Using a mouse model of mild respiratory SARS-CoV-2 infection induced by intranasal SARS-CoV-2 delivery, we found white matter-selective microglial reactivity, a pattern observed in CRCI. Human brain tissue from 9 individuals with COVID-19 or SARS-CoV-2 infection exhibits the same pattern of prominent white matter-selective microglial reactivity. In mice, pro-inflammatory CSF cytokines/chemokines were elevated for at least 7-weeks post-infection; among the chemokines demonstrating persistent elevation is CCL11, which is associated with impairments in neurogenesis and cognitive function. Humans experiencing long-COVID with cognitive symptoms (48 subjects) similarly demonstrate elevated CCL11 levels compared to those with long-COVID who lack cognitive symptoms (15 subjects). Impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss in subcortical white matter were evident at 1 week, and persisted until at least 7 weeks, following mild respiratory SARS-CoV-2 infection in mice. Taken together, the findings presented here illustrate striking similarities between neuropathophysiology after cancer therapy and after SARS-CoV-2 infection, and elucidate cellular deficits that may contribute to lasting neurological symptoms following even mild SARS-CoV-2 infection.

Reduction of pTau and APP levels in mammalian brain after low-dose radiation.

Brain radiation can occur from treatment of brain tumors or accidental exposures. Brain radiation has been rarely considered, though, as a possible tool to alter protein levels involved in neurodegenerative disorders. We analyzed possible molecular and neuropathology changes of phosphorylated-Tau (pTau), all-Tau forms, ß-tubulin, amyloid precursor protein (APP), glial fibrillary acidic protein (GFAP), ionized calcium binding adaptor molecule 1 (IBA-1), myelin basic protein (MBP), and GAP43 in Frontal Cortex (FC), Hippocampus (H) and Cerebellum (CRB) of swine brains following total-body low-dose radiation (1.79 Gy). Our data show that radiated-animals had lower levels of pTau in FC and H, APP in H and CRB, GAP43 in CRB, and higher level of GFAP in H versus sham-animals. These molecular changes were not accompanied by obvious neurohistological changes, except for astrogliosis in the H. These findings are novel, and might open new perspectives on brain radiation as a potential tool to interfere with the accumulation of specific proteins linked to the pathogenesis of various neurodegenerative disorders.

Chronic elevation of plasma vascular endothelial growth factor-A (VEGF-A) is associated with a history of blast exposure.

Mounting evidence points to the significance of neurovascular-related dysfunction in veterans with blast-related mTBI, which is also associated with reduced [18F]-fluorodeoxyglucose (FDG) uptake. The goal of this study was to determine whether plasma VEGF-A is altered in veterans with blast-related mTBI and address whether VEGF-A levels correlate with FDG uptake in the cerebellum, a brain region that is vulnerable to blast-related injury 72 veterans with blast-related mTBI (mTBI) and 24 deployed control (DC) veterans with no lifetime history of TBI were studied. Plasma VEGF-A was significantly elevated in mTBIs compared to DCs. Plasma VEGF-A levels in mTBIs were significantly negatively correlated with FDG uptake in cerebellum. In addition, performance on a Stroop color/word interference task was inversely correlated with plasma VEGF-A levels in blast mTBI veterans. Finally, we observed aberrant perivascular VEGF-A immunoreactivity in postmortem cerebellar tissue and not cortical or hippocampal tissues from blast mTBI veterans. These findings add to the limited number of plasma proteins that are chronically elevated in veterans with a history of blast exposure associated with mTBI. It is likely the elevated VEGF-A levels are from peripheral sources. Nonetheless, increasing plasma VEGF-A concentrations correlated with chronically decreased cerebellar glucose metabolism and poorer performance on tasks involving cognitive inhibition and set shifting. These results strengthen an emerging view that cognitive complaints and functional brain deficits caused by blast exposure are associated with chronic blood-brain barrier injury and prolonged recovery in affected regions.

Early-Onset Dementia in War Veterans: Brain Polypathology and Clinicopathologic Complexity.

The neuropathology associated with cognitive decline in military personnel exposed to traumatic brain injury (TBI) and chronic stress is incompletely understood. Few studies have examined clinicopathologic correlations between phosphorylated-tau neurofibrillary tangles, ß-amyloid neuritic plaques, neuroinflammation, or white matter (WM) lesions, and neuropsychiatric disorders in veterans. We describe clinicopathologic findings in 4 military veterans with early-onset dementia (EOD) who had varying histories of blunt- and blast-TBI, cognitive decline, behavioral abnormalities, post-traumatic stress disorder, suicidal ideation, and suicide. We found that pathologic lesions in these military-EOD cases could not be categorized as classic Alzheimer's disease (AD), chronic traumatic encephalopathy, traumatic axonal injury, or other well-characterized clinicopathologic entities. Rather, we observed a mixture of polypathology with unusual patterns compared with pathologies found in AD or other dementias. Also, ultrahigh resolution ex vivo MRI in 2 of these 4 brains revealed unusual patterns of periventricular WM injury. These findings suggest that military-EOD cases are associated with atypical combinations of brain lesions and distribution rarely seen in nonmilitary populations. Future prospective studies that acquire neuropsychiatric data before and after deployments, as well as genetic and environmental exposure data, are needed to further elucidate clinicopathologic correlations in military-EOD.

Traumatic microbleeds suggest vascular injury and predict disability in traumatic brain injury.

Traumatic microbleeds are small foci of hypointensity seen on T2*-weighted MRI in patients following head trauma that have previously been considered a marker of axonal injury. The linear appearance and location of some traumatic microbleeds suggests a vascular origin. The aims of this study were to: (i) identify and characterize traumatic microbleeds in patients with acute traumatic brain injury; (ii) determine whether appearance of traumatic microbleeds predict clinical outcome; and (iii) describe the pathology underlying traumatic microbleeds in an index patient. Patients presenting to the emergency department following acute head trauma who received a head CT were enrolled within 48 h of injury and received a research MRI. Disability was defined using Glasgow Outcome Scale-Extended ≤6 at follow-up. All magnetic resonance images were interpreted prospectively and were used for subsequent analysis of traumatic microbleeds. Lesions on T2* MRI were stratified based on 'linear' streak-like or 'punctate' petechial-appearing traumatic microbleeds. The brain of an enrolled subject imaged acutely was procured following death for evaluation of traumatic microbleeds using MRI targeted pathology methods. Of the 439 patients enrolled over 78 months, 31% (134/439) had evidence of punctate and/or linear traumatic microbleeds on MRI. Severity of injury, mechanism of injury, and CT findings were associated with traumatic microbleeds on MRI. The presence of traumatic microbleeds was an independent predictor of disability (P < 0.05; odds ratio = 2.5). No differences were found between patients with punctate versus linear appearing microbleeds. Post-mortem imaging and histology revealed traumatic microbleed co-localization with iron-laden macrophages, predominately seen in perivascular space. Evidence of axonal injury was not observed in co-localized histopathological sections. Traumatic microbleeds were prevalent in the population studied and predictive of worse outcome. The source of traumatic microbleed signal on MRI appeared to be iron-laden macrophages in the perivascular space tracking a network of injured vessels. While axonal injury in association with traumatic microbleeds cannot be excluded, recognizing traumatic microbleeds as a form of traumatic vascular injury may aid in identifying patients who could benefit from new therapies targeting the injured vasculature and secondary injury to parenchyma.

Imaging Features Associated With Failure of Nonoperative Management of Intraabdominal Abscesses in Crohn Disease.

BACKGROUND: Intraabdominal abscess management decisions in the treatment of Crohn disease (CD) can be challenging. Our aim was to determine the effect of clinical, medication use, and imaging disease characteristics on the need for future surgical management. METHODS: A retrospective chart review was performed in patients with CD hospitalized for abscess confirmed by imaging between 2008 and 2016. Selection criteria included nonoperative management with intravenous antibiotics at the index hospitalization and a minimum of 2 years of follow up. Demographic, disease, and medication history were extracted from electronic medical records. Radiographic disease features were assessed by an expert abdominal radiologist, blinded to clinical data. The primary outcome was resection of the bowel segment involving the abscess within 2 years of index hospitalization. Cox proportional hazards regression and statistical methods were performed using SAS 9.4. RESULTS: Of the 121 patients meeting the selection criteria, 36.4% avoided surgery after 2 years of follow up. On adjusted multivariable analysis, disease-activity factors including bowel wall thickness (HR 3.08, 95% CL 1.20-6.21), disease length (HR 2.67, 95% CL 1.40-6.20), bowel dilation (HR 2.19, 95% CL 1.02-4.68), and abscess size of greater than 6 cm (HR 2.47, 95%CL 1.17-5.21) were independent risk factors for future surgery in patients not undergoing immediate bowel resection for abscess management. Biologic use and percutaneous drainage were not risk factors for ultimate surgical management. CONCLUSIONS: Radiographic CD features and abscess size over 6 cm are predictors of ultimately requiring bowel resection. Radiographic measures may help stratify patients to immediate surgery or conservative management for intraabdominal CD-related abscesses.

Endoscopic capacity in West Africa.

BACKGROUND: Levels of endoscopic demand and capacity in West Africa are unclear. OBJECTIVES: This paper aims to: 1. describe the current labor and endoscopic capacity, 2. quantify the impact of a mixed-methods endoscopy course on healthcare professionals in West Africa, and 3. quantify the types of diagnoses encountered. METHODS: In a three-day course, healthcare professionals were surveyed on endoscopic resources and capacity and were taught through active observation of live cases, case discussion, simulator experience and didactics. Before and after didactics, multiple-choice exams as well as questionnaires were administered to assess for course efficacy. Also, a case series of 23 patients needing upper GI endoscopy was done. RESULTS: In surveying physicians, less than half had resources to perform an EGD and none could perform an ERCP, while waiting time for emergency endoscopy in urban populations was at least one day. In assessing improvement in medical knowledge among participants after didactics, objective data paired with subjective responses was more useful than either alone. Of 23 patients who received endoscopy, 7 required endoscopic intervention with 6 having gastric or esophageal varices. Currently the endoscopic capacity in West Africa is not sufficient. A formal GI course with simulation and didactics improves gastrointestinal knowledge amongst participants.

In vivo classification of colorectal neoplasia using high-resolution microendoscopy: Improvement with experience.

BACKGROUND AND AIMS: High-resolution microendoscopy (HRME) is a novel, low-cost "optical biopsy" technology that allows for subcellular imaging. The study aim was to evaluate the learning curve of HRME for the differentiation of neoplastic from non-neoplastic colorectal polyps. METHODS: In a prospective cohort fashion, a total of 162 polyps from 97 patients at a single tertiary care center were imaged by HRME and classified in real time as neoplastic (adenomatous, cancer) or non-neoplastic (normal, hyperplastic, inflammatory). Histopathology was the gold standard for comparison. Diagnostic accuracy was examined at three intervals over time throughout the study; the initial interval included the first 40 polyps, the middle interval included the next 40 polyps examined, and the final interval included the last 82 polyps examined. RESULTS: Sensitivity increased significantly from the initial interval (50%) to the middle interval (94%, P = 0.02) and the last interval (97%, P = 0.01). Similarly, specificity was 69% for the initial interval but increased to 92% (P = 0.07) in the middle interval and 96% (P = 0.02) in the last interval. Overall accuracy was 63% for the initial interval and then improved to 93% (P = 0.003) in the middle interval and 96% (P = 0.0007) in the last interval. CONCLUSIONS: In conclusion, this in vivo study demonstrates that an endoscopist without prior colon HRME experience can achieve greater than 90% accuracy for identifying neoplastic colorectal polyps after 40 polyps imaged. HRME is a promising modality to complement white light endoscopy in differentiating neoplastic from non-neoplastic colorectal polyps.

Diagnosis of neoplasia in Barrett's esophagus using vital-dye enhanced fluorescence imaging.

The ability to differentiate benign metaplasia in Barrett's Esophagus (BE) from neoplasia in vivo remains difficult as both tissue types can be flat and indistinguishable with white light imaging alone. As a result, a modality that highlights glandular architecture would be useful to discriminate neoplasia from benign epithelium in the distal esophagus. VFI is a novel technique that uses an exogenous topical fluorescent contrast agent to delineate high grade dysplasia and cancer from benign epithelium. Specifically, the fluorescent images provide spatial resolution of 50 to 100 µm and a field of view up to 2.5 cm, allowing endoscopists to visualize glandular morphology. Upon excitation, classic Barrett's metaplasia appears as continuous, evenly-spaced glands and an overall homogenous morphology; in contrast, neoplastic tissue appears crowded with complete obliteration of the glandular framework. Here we provide an overview of the instrumentation and enumerate the protocol of this new technique. While VFI affords a gastroenterologist with the glandular architecture of suspicious tissue, cellular dysplasia cannot be resolved with this modality. As such, one cannot morphologically distinguish Barrett's metaplasia from BE with Low-Grade Dysplasia via this imaging modality. By trading off a decrease in resolution with a greater field of view, this imaging system can be used at the very least as a red-flag imaging device to target and biopsy suspicious lesions; yet, if the accuracy measures are promising, VFI may become the standard imaging technique for the diagnosis of neoplasia (defined as either high grade dysplasia or cancer) in the distal esophagus.

In vivo diagnostic accuracy of high-resolution microendoscopy in differentiating neoplastic from non-neoplastic colorectal polyps: a prospective study.

OBJECTIVES: High-resolution microendoscopy (HRME) is a low-cost, "optical biopsy" technology that allows for subcellular imaging. The purpose of this study was to determine the in vivo diagnostic accuracy of the HRME for the differentiation of neoplastic from non-neoplastic colorectal polyps and compare it to that of high-definition white-light endoscopy (WLE) with histopathology as the gold standard. METHODS: Three endoscopists prospectively detected a total of 171 polyps from 94 patients that were then imaged by HRME and classified in real-time as neoplastic (adenomatous, cancer) or non-neoplastic (normal, hyperplastic, inflammatory). RESULTS: HRME had a significantly higher accuracy (94%), specificity (95%), and positive predictive value (PPV, 87%) for the determination of neoplastic colorectal polyps compared with WLE (65%, 39%, and 55%, respectively). When looking at small colorectal polyps (less than 10 mm), HRME continued to significantly outperform WLE in terms of accuracy (95% vs. 64%), specificity (98% vs. 40%) and PPV (92% vs. 55%). These trends continued when evaluating diminutive polyps (less than 5 mm) as HRME's accuracy (95%), specificity (98%), and PPV (93%) were all significantly greater than their WLE counterparts (62%, 41%, and 53%, respectively). CONCLUSIONS: In conclusion, this in vivo study demonstrates that HRME can be a very effective modality in the differentiation of neoplastic and non-neoplastic colorectal polyps. A combination of standard white-light colonoscopy for polyp detection and HRME for polyp classification has the potential to truly allow the endoscopist to selectively determine which lesions can be left in situ, which lesions can simply be discarded, and which lesions need formal histopathologic analysis.

Encephalitozoon cuniculi-Associated Equine Encephalitis: A Case Report.

A case of encephalitis of unknown origin in the horse was investigated. Postmortem examination findings revealed a nonsuppurative granulomatous meningoencephalitis in the right hemisphere of the cerebral cortex. Testing for West Nile virus, equine herpes virus, equine infectious anemia, Toxoplasma gondii, Neospora caninum, and Sarcocystis neurona were negative. The horse had a titer for Encephalitozoon cuniculi, and sections from the affected area of the brain tested positive for the organism using both polymerase chain reaction (PCR) and immunohistochemistry. Amplicons generated using PCR were sequenced, and E. cuniculi genotype II was identified. This is the first case of E. cuniculi genotype II associated with encephalitis in the horse.

The role of the pathologist in translational and personalized medicine.

Over the years, pathologists have served to make morphologic diagnoses for clinicians when provided with a biopsy or surgically resected tissue specimen. Traditionally, pathologists have used a series of morphologic techniques and relied on the microscopic appearance of resected tissues to determine a pathologic diagnosis and, with respect to neoplastic lesions, provide predictions of the potential growth pattern that might be anticipated. With the introduction of the techniques of molecular biology in medicine, the role of the pathologist has changed as have the tools available for characterizing pathologic specimens. With the pathologist's unique perspective on disease processes and access to tissue specimens from the operating room, he has become a key player in the area of translational and personalized medicine and the development of new approaches to diagnosis and translational research.