Genetic Divergence of Toxoplasma gondii Strains Associated with Ocular Toxoplasmosis, Brazil

Brazilian strains of T. gondii differ from lineages in North America and Europe; these differences may underlie severe ocular disease

An assessment of the reliability of three methods used in evaluating the status of multiple sclerosis patients

The reliability of three different evaluation methods used in a cooperative clinical trial of the efficacy of ACTH in multiple sclerosis patients was evaluated in a uniformity study that used an efficient statistical design requiring only 10 patients and 5 examiners. The methods were the standard neurologic examination, a scoring system for functional grades and disability status, and a 7-day symptom score. Each patient was examined only 3 times at the beginning of the study and 3 more times 6 days later. No significant differences among the 5 examiners were observed on 82 of the 87 items used to measure neurologic function. With the exception of 1 variable, there were no significant differences among the average values of the sequence of the 3 examinations, nor among the average increments of change in the numerical scores between the first and second trials.In an additional examination in which all 5 examiners simultaneously evaluated 3 patients 1 at a time, it was found that the 5 examiners observed uniformly in all of the neurologic tests.The results of this study indicate that, by and large, the three evaluation methods appear to be reliable in the evaluation of neurologic status when used in a cooperative clinical trial where several investigators contribute data. Furthermore, investigations of reliability in cooperative studies can be performed with the use of efficient statistical designs such as the incomplete Latin-square design.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32998/1/0000382.pd

Neuropathological Findings In Chronic Relapsing Experimental Allergic Neuritis Induced In The Lewis Rat By Inoculation With Intradural Root Myelin And Treatment With Low Dose Cyclosporin A

Experimental allergic neuritis (EAN) was induced in Lewis rats by inoculation with bovine intradural root myelin and adjuvants. Rats treated with subcutaneous cyclosporin A (CsA) (4mg/kg on 3 days per week from the day of inoculation until day 29) developed a chronic relapsing course. Tissues from the spinal cord, nerve roots, dorsal root ganglia and sciatic nerve of CsA-treated rats sampled during relapses and remissions were studied during or after episodes of acute EAN. Both control and CsA-treated animals studied in the first episode of EAN had evidence of inflammation and primary demyelination of the nerve roots and dorsal root ganglia. In control and CsA-treated animals in the second episode there was severe inflammation and demyelination and remyelination in the spinal nerves and sciatic nerves and dorsal columns of the spinal cord, particularly in later stages of the disease. In later episodes there was less inflammation, but there was continuing demyelination and onion bulbs were present. In animals sampled after recovery from chronic relapsing EAN onion bulbs were present. Occasional small onion bulbs were also observed in control animals that were inoculated with higher doses of myelin. Plasma cells were present in the inflammatory lesions of later episodes. Mast cells were also observed at different stages of the disease. We conclude that the CsA form of chronic relapsing EAN has clinical and pathological similarities with the human disease, chronic inflammatory demyelinating polyradiculoneuropathy

A prospective, multi-site, cohort study to estimate incidence of infection and disease due to Lassa fever virus in West African countries (the Enable Lassa research programme)–Study protocol

Background Lassa fever (LF), a haemorrhagic illness caused by the Lassa fever virus (LASV), is endemic in West Africa and causes 5000 fatalities every year. The true prevalence and incidence rates of LF are unknown as infections are often asymptomatic, clinical presentations are varied, and surveillance systems are not robust. The aim of the Enable Lassa research programme is to estimate the incidences of LASV infection and LF disease in five West African countries. The core protocol described here harmonises key study components, such as eligibility criteria, case definitions, outcome measures, and laboratory tests, which will maximise the comparability of data for between-country analyses. Method We are conducting a prospective cohort study in Benin, Guinea, Liberia, Nigeria (three sites), and Sierra Leone from 2020 to 2023, with 24 months of follow-up. Each site will assess the incidence of LASV infection, LF disease, or both. When both incidences are assessed the LASV cohort (nmin = 1000 per site) will be drawn from the LF cohort (nmin = 5000 per site). During recruitment participants will complete questionnaires on household composition, socioeconomic status, demographic characteristics, and LF history, and blood samples will be collected to determine IgG LASV serostatus. LF disease cohort participants will be contacted biweekly to identify acute febrile cases, from whom blood samples will be drawn to test for active LASV infection using RT-PCR. Symptom and treatment data will be abstracted from medical records of LF cases. LF survivors will be followed up after four months to assess sequelae, specifically sensorineural hearing loss. LASV infection cohort participants will be asked for a blood sample every six months to assess LASV serostatus (IgG and IgM). Discussion Data on LASV infection and LF disease incidence in West Africa from this research programme will determine the feasibility of future Phase IIb or III clinical trials for LF vaccine candidates

Energy transfer in unirradiated and irradiated RbMnF3 and RbMnF3 : Er

Le transfert d'énergie joue un rôle majeur dans la plupart des processus d'up-conversion et dans certains lasers. Les impuretés et aussi les défauts induits par la radiation sont tous deux capables de modifier le transfert d'énergie dans les matières de façon soit constructive soit destructive, selon le système. Dans cette étude nous présentons, sur les propriétés optiques de RbMnF3, et de RbMnF3 : Er, des données prises par des mesures d'absorption, d'émission, d'excitation et de durée de vie. Dans une matière non irradiée les propriétés optiques peuvent être décrites par les paramètres de champ cristallin et par l'emploi des analyses de Struck et Fonger et de Flaherty et DiBartolo. Dans le cas des matières irradiées, les énormes changements de grandeur oscillante pour les ions Mn2+ situés à côté d'interstitiels induits par la radiation ou de centres F, peuvent modifier fortement le processus du transfert d'énergie.Energy transfer plays a major role in most up-conversion processes and in some lasers. Both impurities and radiation-induced defects can affect the energy transfer in materials either constructively or destructively, depending on the system. In this study we present data on the optical properties of RbMnF3 and RbMnF3 : Er from measurements of the absorption, emission, excitation and lifetimes. In unirradiated material the optical properties can be described by crystal field parameters and by the use of the analysis of Struck and Fonger, and Flaherty and DiBartolo. In the case of irradiated materials, the huge oscillator strength changes for Mn2+ ions located next to radiation-induced interstitials or F centres can strongly affect the energy transfer process

INFRARED LIGHT TO VISIBLE LIGHT UPCONVERSION IN HEAVY METAL FLUORIDE GLASSES

The efficient change of infrared light to visible light has important positive implications for optical detection and display devises. On the other hand, this process can, in some instances, such as the development of laser sources in fibers, result in unwanted effects. In this paper, the efficiency of the two photon upconversion process in heavy metal fluoride gallses and in halide crystals is reviewed. Methods for increasing or reducing the efficiency of the upconversion process as applicable to display, optical detection devices and the formation of efficient laser systems in fibers are discussed