Pediatric arteriovenous malformation: University of Toronto experience using stereotactic radiosurgery

Introduction and background Arteriovenous malformations (AVMs) are congenital vascular lesions of the brain, which behave differently in pediatric population compared to adults. Treatment of pediatric AVMs includes a combination of microsurgery, embolization and radiation therapies. However, the role of radiosurgery in the treatment of pediatric AVMs is not fully accepted because of concerns regarding the long-term effects of radiation on the pediatric brain. Discussion In this study, we review our experience at the University of Toronto with treating pediatric AVMs using linear accelerator-based (LINAC) radiosurgery over the past 15 years. We report our results, obliteration rates, and complications on a total of 40 patients. In addition, we provide a review of series published to date combined with our own results to determine whether radiosurgery is a safe and reasonable treatment modality for pediatric AVMs.     

Melasma: Successful treatment with pidobenzone 4% (K5®lipogel)

ABSTRACT:  Melasma (a term derived from the Greek word "melas" meaning black) is an acquired blotchy, irregularly patterned, brown or sometimes gray brown hypermelanosis of the face and occasionally the neck. Its etiology is poorly understood but mainly related to sunlight and genetic predisposition. Melasma seems to be more frequent in darker skinned people, especially women. Its treatment is always difficult and the condition usually relapses. The treatment with pidobenzone 4% (K5^® lipogel), twice per day for 16 weeks has proved to be safe and effective. Pidobenzone 4% lipogel, according to the present study, seems also to represent a useful, reliable, and safe treatment of the different types of melasma.     

Impact of Gastrointestinal Bacillus anthracis Infection on Hepatic B Cells

Ingestion of Bacillus anthracis results in rapid gastrointestinal (GI) infection, known as GI anthrax. We previously showed that during GI anthrax, there is swift deterioration of intestinal barrier function leading to translocation of gut-associated bacteria into systemic circulation. Additionally, we described dysfunction in colonic B cells. In concordance with our previous studies, here, we report early migration of the Sterne strain of B. anthracis along with other gut-resident bacteria into the infected murine liver. Additionally, despite a global decrease in the B cell population, we observed an increase in both B-1a and marginal zone (MZ)-like B cells. Both of these cell types are capable of producing immunoglobulins against common pathogens and commensals, which act as a general antibody barrier before an antigen-specific antibody response. Accumulation of these cells in the liver was associated with an increase in chemokine expression. These data suggest that the presence of Sterne and other commensals in the liver trigger migration of MZ-like B cells from the spleen to the liver to neutralize systemic spread. Further research is required to evaluate the possible cause of their failure to clear the infection within the liver, including the potential role of dysfunctional mitogen-activated protein kinase (MAPK) signaling.     

Exosomes and their role in CNS viral infections

Exosomes are small membrane-bound vesicles that carry biological macromolecules from the site of production to target sites either in the microenvironment or at distant sites away from the origin. Exosomal content of cells varies with the cell type that produces them as well as environmental factors that alter the normal state of the cell such as viral infection. Human DNA and RNA viruses alter the composition of host proteins as well as incorporate their own viral proteins and other cargo into the secreted exosomes. While numerous viruses can infect various cell types of the CNS and elicit damaging neuropathologies, few have been studied for their exosomal composition, content, and function on recipient cells. Therefore, there is a pressing need to understand how DNA and RNA viral infections in CNS control exosomal release. Some of the more recent studies including HIV-1, HTLV-1, and EBV-infected B cells indicate that exosomes from these infections contain viral miRNAs, viral transactivators, and a host of cytokines that can control the course of infection. Finally, because exosomes can serve as vehicles for the cellular delivery of proteins and RNA and given that the blood-brain barrier is a formidable challenge in delivering therapeutics to the brain, exosomes may be able to serve as ideal vehicles to deliver protein or RNA-based therapeutics to the brain.     

Treatment and follow up of disseminated and late Lyme disease

The aim of this review was to analyze the current strategies of treatment and follow-up of disseminated and late Lyme borreliosis. A comprehensive search was performed using the Medline database. Only relevant reviews, expert guidelines and randomized controlled clinical trials were selected and, if necessary, open trials. Major drugs used in these studies were amoxicillin, doxycycline, penicillin G, and ceftriaxone. Oral administration of antibiotics was preferred in Lyme arthritis whereas parenteral drugs were mostly used in neuroborreliosis. The treatment duration usually ranged from 14 to 30 days. Prolonged antibiotic courses recommended by some authors in post-Lyme syndromes were not validated by several randomized placebo controlled studies. Follow up patterns were analyzed in order to determine possible prognosis parameters allowing to distinguih active Borrelia burgdorferi infection from a sequel of infection.