Clinical review of retinotopy

Two observations made 29 years apart are the cornerstones of this review on the contributions of Dr Gordon T. Plant to understanding pathology affecting the optic nerve. The first observation laid the anatomical basis in 1990 for the interpretation of optical coherence tomography (OCT) findings in 2009. Retinal OCT offers clinicians detailed in vivo structural imaging of individual retinal layers. This has led to novel observations which were impossible to make using ophthalmoscopy. The technique also helps to re-introduce the anatomically grounded concept of retinotopy to clinical practise. This review employs illustrations of the anatomical basis for retinotopy through detailed translational histological studies and multimodal brain-eye imaging studies. The paths of the prelaminar and postlaminar axons forming the optic nerve and their postsynaptic path from the dorsal lateral geniculate nucleus to the primary visual cortex in humans are described. With the mapped neuroanatomy in mind we use OCT-MRI pairings to discuss the patterns of neurodegeneration in eye and brain that are a consequence of the hard wired retinotopy: anterograde and retrograde axonal degeneration which can, within the visual system, propagate trans-synaptically. The technical advances of OCT and MRI for the first time enable us to trace axonal degeneration through the entire visual system at spectacular resolution. In conclusion, the neuroanatomical insights provided by the combination of OCT and MRI allows us to separate incidental findings from sinister pathology and provides new opportunities to tailor and monitor novel neuroprotective strategies

Periodic Host Absence Can Select for Higher or Lower Parasite Transmission Rates

This paper explores the effect of discontinuous periodic host absence on the evolution of pathogen transmission rates by using Ro maximisation techniques. The physiological consequence of an increased transmission rate can be either an increased virulence, i.e. there is a transmission-virulence trade-off or ii) a reduced between season survival, i.e. there is a transmission-survival trade-off. The results reveal that the type of trade-off determines the direction of selection, with relatively longer periods of host absence selecting for higher transmission rates in the presence of a trade-off between transmission and virulence but lower transmission rates in the presence of a trade-of between transmission and between season survival. The fact that for the transmission-virulence trade-off both trade-off parameters operate during host presence whereas for the transmission-survival trade-off one operates during host presence (transmission) and the other (survival) during the period of host absence is the main cause for this difference in selection direction. Moreover, the period of host absence seems to be the key determinant of the pathogens transmission rate. Comparing plant patho-systems with contrasting biological features suggests that airborne plant pathogen respond differently to longer periods of host absence than soil-borne plant pathogens

What an endoscopist should know about immunoglobulin-G4-associated disease of the pancreas and biliary tree

Autoimmune pancreatitis (AIP) and IgG4-associated cholangitis (IAC) are the recently recognized pancreatobiliary manifestations of IgG4-associated systemic disease (ISD). Clinically, ISD of the pancreas and/or biliary tree may mimic pancreatic cancer, sclerosing cholangitis, or cholangiocarcinoma. Patients often present with abdominal pain, weight loss, jaundice, itch, and biochemical signs of pancreatitis and cholestasis. Tomography may reveal enlargement of the pancreas or may mimic malignant pancreatic lesions, and cholangiopancreatography may disclose irregularities of the pancreatic duct and stenoses of the distal and/or proximal common bile duct and intrahepatic bile ductules. Serum immunoglobu-lin G4 (IgG4) is elevated in most patients but, unlike tissue IgG4-loaded plasma cell infiltrates, is not diagnostic of the disease. The application of consensus diagnostic criteria for laboratory investigations, imaging, and histologic findings can identify patients who qualify for corticosteroid treatment. The excellent response to immunosuppressive therapy suggests an immune-mediated etiology of the disease, but the exact pathophysiological mechanisms are still under investigation. Relapse may occur after tapering down of corticosteroids, which supports the rationale of maintenance immunosuppression after remission has been induce

Exposure to occupational antigens might predispose to IgG4-related disease

Evidence is mounting that the immune system of patients with IgG4-related disease (IgG4-RD) shows indications of chronic antigenic stimulation. Hypothesizing a possible role for occupational antigenic exposure, we observed in two independent cohorts of patients with IgG4-RD that the majority had had a career in blue collar occupations with prolonged exposures to potentially hazardous occupational antigens. We postulate that the chronic antigenic load associated with 'dirty' jobs could be one of the factors contributing to the development of IgG4-related disease. (Hepatology 2014;

Temporal Relationship of Sex Risk Behaviors and Substance Use Severity Among Men in Substance Use Treatment

Sex risk behaviors and substance use are intertwined. Many men continue to engage in high-risk sexual behaviors even when enrolled in substance use disorder (SUD) treatment. We hypothesized that changes in sex risk behaviors would coincide with changes in drug/alcohol use severity among men in SUD treatment. During an HIV risk-reduction trial, men in methadone maintenance and outpatient drug-free treatment (N = 359) completed assessments at baseline and six months after. We assessed changes in sex risk and substance use severity, using the Addiction Severity Index-Lite (ASI-Lite), controlling for treatment condition. In multinomial logistic regressions, decreased alcohol severity was significantly associated with decreases in reported sex partners, and increased alcohol severity was significantly associated with increases in reported sex partners. Increasing drug use severity was significantly associated with maintaining and initiating sex with a high-risk partner, while decreasing alcohol use severity was significantly associated with discontinuing sex under the influence. However, changes in drug/alcohol use severity were not associated with changes in unprotected sex. Substance use reductions may decrease HIV risk behaviors among male substance users. Our findings highlight the importance of integrating interventions in SUD treatment settings that address the intersection of sex risk behaviors and substance use

Molecular Targets for the Treatment of Fibrosing Cholangiopathies

Emerging pathophysiologic insights are leading to novel approaches to treating fibrosing cholangiopathies. The current treatment, using ursodeoxycholic acid (UDCA), may slow the progression of some chronic cholangiopathies but cannot heal them. Apart from immunosuppressive interventions aimed at minimizing immune-mediated damage, the use of specific modifiers of hepatobiliary secretory and cytoprotective mechanisms may eventually give rise to a new class of disease-modifying anticholangiofibrotic drug