scholarly journals EXPERIMENTAL CONGENITAL TOXOPLASMOSIS

1950 ◽  
Vol 92 (5) ◽  
pp. 417-429 ◽  
Author(s):  
David Cowen ◽  
Abner Wolf
Keyword(s):  
Congenital Toxoplasmosis ◽  
Congenital Infection ◽  
Human Infant ◽  
Time Interval ◽  
Vaginal Route ◽  
Individual Offspring ◽  
The Individual ◽  
Portal Of Entry ◽  
Degrees Of Severity ◽  
Young Mice

A study has been made of congenital toxoplasmosis in the offspring of mice infected with Toxoplasma by the vaginal route during pregnancy. Some of the young mice were retarded in postnatal development, and some became ill or died in the 2nd to 4th weeks of life while the majority remained symptom-free in spite of the presence of toxoplasmic lesions of varying degrees of severity. Congenital toxoplasmosis developed only in offspring whose mothers had been infected on the 7th to 9th day of pregnancy. Infection of the offspring without active toxoplasmosis in the mother was not observed. The highest incidence of congenital infection (57.6 per cent) was obtained by giving 2 vaginal instillations of Toxoplasma-infected mouse brain on the 8th and 9th days of pregnancy. Mice infected before the 7th day developed placental toxoplasmosis but rarely delivered viable young. When the mother was infected after the 9th day, the offspring were normal. When congenital toxoplasmosis occurred in a litter, a majority or all of the individual offspring were usually infected. Although pathologic changes were not present in the suckling mice at birth, and did not appear before the 9th postnatal day, reasons are stated for excluding the possibility of postnatal contact or milk-borne infection. It cannot be assumed from the experimental disease that the vagina is a portal of entry of Toxoplasma in human congenital toxoplasmosis. Any route of infection leading to a maternal parasitemia during pregnancy might result in toxoplasmosis of the placenta and transmission of the disease to the offspring before birth. Unlike the restricted time interval effective in the mouse, there is a long period during the later months of pregnancy in the human being in which transplacental passage of the infection may occur. When transmission to the fetus takes place shortly before parturition, evidence of disease in the human infant, as in the mouse, may not become manifest until several weeks postpartum, and the prenatal origin of the infection may not be apparent. When the fetus becomes infected well before parturition, symptoms of congenital toxoplasmosis may be present at birth. The asymptomatic character of the infection in many of the young mice would appear to have a counterpart in certain instances of human congenital toxoplasmosis.

scholarly journals EXPERIMENTAL CONGENITAL TOXOPLASMOSIS

1950 ◽  
Vol 92 (5) ◽  
pp. 403-416 ◽  
Author(s):  
David Cowen ◽  
Abner Wolf
Keyword(s):  
Congenital Toxoplasmosis ◽  
Blood Stream ◽  
Vaginal Wall ◽  
Essential Factor ◽  
Vaginal Route ◽  
Normal Test ◽  
Pregnant Mice ◽  
Placental Blood ◽  
Portal Of Entry ◽  
Syncytial Trophoblast

Pregnant mice infected with Toxoplasma by the vaginal route have been found to transmit toxoplasmosis to the placentas and fetuses in utero. The microorganism entered the blood stream of the mother from primary foci of infection in the vaginal wall and produced disseminated lesions in the labyrinth of the allantoic placenta at the same time as other peripheral maternal tissues were involved. Placental lesions were observed in mice infected with Toxoplasma by vagina between the 3rd and the 9th day of pregnancy. They consisted of microscopic foci of degeneration, without inflammation, in the syncytial trophoblast, and parasites undergoing multiplication were readily identified in them. Here Toxoplasma gained access to the fetal circulation. Following the vaginal instillation of Toxoplasma on the 8th day of pregnancy, subinoculation of test animals revealed the parasites in the maternal peripheral and placental blood on the 13th day and later, while the first histopathologic changes in the placenta were found on the 17th day. Toxoplasma could be demonstrated in suspensions of fetal tissues on and after the 17th day by the injection of normal test animals. However, no lesions of toxoplasmosis, or Toxoplasma, were found in histologic sections of fetuses 11 to 21 days old removed at autopsy from vaginally infected mothers. It is concluded that before birth the parasites were confined to the fetal blood. The experiments provide the first direct histological demonstration of placental toxoplasmosis. The possible bearing of the experimental disease on human placental and fetal toxoplasmosis is briefly considered. It is probable that a maternal parasitemia during the latter part of pregnancy, whatever the portal of entry may be, is an essential factor in the pathogenesis of human congenital toxoplasmosis and that this occurs shortly after exposure to Toxoplasma rather than in a later chronic stage of the infection. The suggestion is offered that some instances of spontaneous abortion or fetal death in man, as in the mouse, may be due to inapparent toxoplasmosis.

LONG‐TIME RESPONSE PREDICTED BY EXACT ELASTIC RAY THEORY

Geophysics ◽  
1965 ◽  
Vol 30 (3) ◽  
pp. 363-368 ◽  
Author(s):  
T. W. Spencer
Keyword(s):  
Formal Solution ◽  
Intermediate Stage ◽  
Time Limit ◽  
Time Interval ◽  
Individual Response ◽  
Axially Symmetric ◽  
Long Time ◽  
The Difference ◽  
The Individual ◽  
Significant Figures

The formal solution for an axially symmetric radiation field in a multilayered, elastic system can be expanded in an infinite series. Each term in the series is associated with a particular raypath. It is shown that in the long‐time limit the individual response functions produced by a step input in particle velocity are given by polynomials in odd powers of the time. For rays which suffer m reflections, the degree of the polynomials is 2m+1. The total response is obtained by summing all rays which contribute in a specified time interval. When the rays are selected indiscriminately, the difference between the magnitude of the partial sum at an intermediate stage of computation and the magnitude of the correct total sum may be greater than the number of significant figures carried by the computer. A prescription is stated for arranging the rays into groups. Each group response function varies linearly in the long‐time limit and goes to zero when convolved with a physically realizable source function.

Time Estimation Performance Before, during and after Physical Activity

1988 ◽  
Vol 32 (15) ◽  
pp. 985-989 ◽  
Author(s):  
T. Mihaly ◽  
P.A. Hancock ◽  
M. Vercruyssen ◽  
M. Rahimi
Keyword(s):  
Interval Estimation ◽  
Time Estimation ◽  
Cycle Ergometer ◽  
Estimation Accuracy ◽  
Physical Work ◽  
Time Interval ◽  
Individual Subject ◽  
Knowledge Of Results ◽  
The Individual ◽  
Experimental Findings

An experiment is reported which evaluated performance on a 10-sec time interval estimation task before, during and after physical work on cycle ergometer at intensities of 30 and 60% VO2max, as scaled to the individual subject. Results from the eleven subjects tested indicate a significant increase in variability of estimates during exercise compared to non-exercise phases. Such a trend was also seen in the mean of estimates, where subjects significantly underestimated the target interval (10 seconds) during exercise. Subjects also performed more accurately with information feedback than without knowledge of results, but they were still not able to overcome the effects of exercise. As suggested by the experimental findings, decreased estimation accuracy and increased variability can be expected during physical work and is part of a body of evidence which indicates that exercise and its severity has a substantive impact on perceptual and cognitive performance.

scholarly journals Growth Hormone Deficiency in Congenital Toxoplasmosis

2018 ◽  
Vol 08 (01) ◽  
pp. e43-e45
Author(s):  
Juma Natsheh ◽  
Bassam Abu-Libdeh ◽  
Abdulsalam Abu-Libdeh
Keyword(s):  
Growth Hormone ◽  
Growth Hormone Deficiency ◽  
Congenital Toxoplasmosis ◽  
Congenital Infection ◽  
Failure To Thrive ◽  
Female Infant ◽  
Pituitary Function ◽  
Hormone Deficiency ◽  
Neurological Abnormalities

AbstractCongenital toxoplasmosis represents the second most commonly recognized congenital infection. Ocular and neurological abnormalities are considered the most frequent sequelae. Endocrinological manifestations are rare and have received little attention. We report a 3.5-month-old female infant who presented with failure to thrive and recurrent hypoglycemic attacks, diagnosed as growth hormone deficiency due to sequelae of congenital toxoplasmosis. Although endocrinological sequelae of congenital toxoplasmosis are uncommon, they represent potentially treatable conditions. Here, we stress on the importance of monitoring pituitary function and growth in children in particular, with congenital toxoplasmosis, keeping in mind other possible, potentially treatable, endocrinological manifestations.

scholarly journals An algorithm for the estimation of road traffic space mean speeds from double loop detector data

2016 ◽  
Author(s):  
Margarita Martínez-Díaz ◽  
Ignacio Pérez Pérez
Keyword(s):  
Traffic Management ◽  
Road Traffic ◽  
Time Interval ◽  
Double Loop ◽  
Negative Effects ◽  
Loop Detectors ◽  
The Common ◽  
Log Normal ◽  
The Individual ◽  
Log Normal Distribution

Most algorithms trying to analyze or forecast road traffic rely on many inputs, but in practice, calculations are usually limited by the available data and measurement equipment. Generally, some of these inputs are substituted by raw or even inappropriate estimations, which in some cases come into conflict with the fundamentals of traffic flow theory. This paper refers to one common example of these bad practices. Many traffic management centres depend on the data provided by double loop detectors, which supply, among others, vehicle speeds. The common data treatment is to compute the arithmetic mean of these speeds over different aggregation periods (i.e. the time mean speeds). Time mean speed is not consistent with Edie’s generalized definitions of traffic variables, and therefore it is not the average speed which relates flow to density. This means that current practice begins with an error that can have negative effects in later studies and applications. The algorithm introduced in this paper enables easily the estimation of space mean speeds from the data provided by the loops. It is based on two key hypotheses: stationarity of traffic and log-normal distribution of the individual speeds in each time interval of aggregation. It could also be used in case of transient traffic as a part of any data fusion methodology.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3208 

A PROPOSED FORMULA FOR HORIZONTAL REVENUE ALLOCATION IN NIGERIA

2012 ◽  
Vol 29 (06) ◽  
pp. 1250033
Author(s):  
VIRTUE U. EKHOSUEHI ◽  
AUGUSTINE A. OSAGIEDE
Keyword(s):  
Optimal Control ◽  
Federal Government ◽  
Optimal Control Theory ◽  
Fixed Time ◽  
Tax Revenue ◽  
Time Interval ◽  
Fixed Time Interval ◽  
Hypothetical Data ◽  
Revenue Allocation ◽  
The Individual

In this study, we have applied optimal control theory to determine the optimum value of tax revenues accruing to a state given the range of budgeted expenditure on enforcing tax laws and awareness creation on the payment of the correct tax. This is achieved by maximizing the state's net tax revenue over a fixed time interval subject to certain constraints. By assuming that the satisfaction derived by the Federal Government of Nigeria on the ability of the individual states to generate tax revenue which is as near as the optimum tax revenue (via the state's control problem) is described by the logarithmic form of the Cobb–Douglas utility function, a formula for horizontal revenue allocation in Nigeria in its raw form is derived. Afterwards, we illustrate the use of the proposed horizontal revenue allocation formula using hypothetical data.

scholarly journals Maternal and Congenital Toxoplasmosis: Diagnosis and Treatment Recommendations of a French Multidisciplinary Working Group

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 24 ◽  
Author(s):  
François Peyron ◽  
Coralie L’ollivier ◽  
Laurent Mandelbrot ◽  
Martine Wallon ◽  
Renaud Piarroux ◽  
...  
Keyword(s):  
Working Group ◽  
Congenital Toxoplasmosis ◽  
Congenital Infection ◽  
Before And After ◽  
Multidisciplinary Working ◽  
Neurological Alterations ◽  
Multidisciplinary Group ◽  
Toxoplasmosis During Pregnancy

Women infected with toxoplasmosis during pregnancy do not present symptoms in most cases, but the consequences of the congenital infection may be severe for the unborn child. Fetal damage can range from asymptomatic to severe neurological alterations to retinal lesions prone to potential flare up and relapses lifelong. Despite the possible severity of outcome, congenital toxoplasmosis (CT) is a neglected disease. There is no consensus regarding screening during pregnancy, prenatal/postnatal treatment or short or medium term follow-up. Since 1992, France has offered systematic serological testing to non-immune pregnant women, monthly until delivery. Any maternal infection is thus detected; moreover, diagnosis of congenital infection can be made at birth and follow-up can be provided. “Guidelines” drawn up by a multidisciplinary group are presented here, concerning treatment, before and after birth. The recommendations are based on the regular analysis of the literature and the results of the working group. The evaluation of the recommendations takes into account the robustness of the recommendation and the quality of the evidence.

scholarly journals RHΔgra17Δnpt1 Strain of Toxoplasma gondii Elicits Protective Immunity Against Acute, Chronic and Congenital Toxoplasmosis in Mice

2020 ◽  
Vol 8 (3) ◽  
pp. 352 ◽  
Author(s):  
Qin-Li Liang ◽  
Li-Xiu Sun ◽  
Hany M. Elsheikha ◽  
Xue-Zhen Cao ◽  
Lan-Bi Nie ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Cellular Response ◽  
Protective Efficacy ◽  
Interleukin 2 ◽  
Congenital Toxoplasmosis ◽  
Congenital Infection ◽  
Dense Granule ◽  
Lethal Challenge ◽  
Double Deletion ◽  
Brain Cysts

In the present study, a dense granule protein 17 (gra17) and novel putative transporter (npt1) double deletion mutant of Toxoplasma gondii RH strain was engineered. The protective efficacy of vaccination using RHΔgra17Δnpt1 tachyzoites against acute, chronic, and congenital toxoplasmosis was studied in a mouse model. Immunization using RHΔgra17Δnpt1 induced a strong humoral and cellular response, as indicated by the increased levels of anti-T. gondii specific IgG, interleukin 2 (IL-2), IL-10, IL-12, and interferon-gamma (IFN-γ). Vaccinated mice were protected against a lethal challenge dose (103 tachyzoites) of wild-type homologous (RH) strain and heterologous (PYS and TgC7) strains, as well as against 100 tissue cysts or oocysts of Pru strain. Vaccination also conferred protection against chronic infection with 10 tissue cysts or oocysts of Pru strain, where the numbers of brain cysts in the vaccinated mice were significantly reduced compared to those detected in the control (unvaccinated + infected) mice. In addition, vaccination protected against congenital infection with 10 T. gondii Pru oocysts (administered orally on day 5 of gestation) as shown by the increased litter size, survival rate and the bodyweight of pups born to vaccinated dams compared to those born to unvaccinated + infected dams. The brain cyst burden of vaccinated dams was significantly lower than that of unvaccinated dams infected with oocysts. Our data show that T. gondii RHΔgra17Δnpt1 mutant strain can protect mice against acute, chronic, and congenital toxoplasmosis by balancing inflammatory response with immunogenicity.

scholarly journals Incidence of congenital toxoplasmosis in southern Brazil: a prospective study

2003 ◽  
Vol 45 (3) ◽  
pp. 147-151 ◽  
Author(s):  
Liége Mozzatto ◽  
Renato Soibelmann Procianoy
Keyword(s):  
Toxoplasma Gondii ◽  
Gestational Age ◽  
Newborn Infants ◽  
Congenital Toxoplasmosis ◽  
Congenital Infection ◽  
First Trimester ◽  
Laboratory Diagnosis ◽  
Anthropometric Measures ◽  
Maternal Characteristics ◽  
The Town

The study aimed to determine the incidence of congenital infection by Toxoplasma gondii and to describe neonatal and maternal characteristics regarding newborn infants treated at a teaching hospital in the town of Passo Fundo, State of Rio Grande do Sul, Brazil. Cord blood samples collected from 1,250 live newborns were analyzed. The laboratory diagnosis was established by the detection of Toxoplasma gondii IgM using an enzyme linked fluorescent assay. Gestational age, intrauterine growth, anthropometric measures, and prenatal characteristics were assessed. The incidence of congenital toxoplasmosis at birth was 8/10,000 (95%CI 0.2-44.5). Mean birthweight was 3,080 ± 215.56 grams and mean gestational age was 38.43 ± 1.88 weeks. With regard to prenatal care, 58% of the pregnant patients visited their doctors five times or more and 38.9% were serologically tested for toxoplasmosis in the first trimester of pregnancy. The incidence of congenital toxoplasmosis was similar to that found in most studies conducted in our country and abroad. Our study sample is representative of the town of Passo Fundo and therefore it is possible to consider the frequency observed as the prevalence of the disease in this town during the study period.

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