The distribution of Nematospiroides dubius within the small intestine of laboratory mice

1976 ◽  
Vol 50 (3) ◽  
pp. 163-171 ◽  
Author(s):  
J. W. Lewis ◽  
V. Bryant

AbstractAnalyses of primary infections of Nematospiroides dubius in male and female laboratory mice show that on days 4–6 post-infection worms occupy up to 50% of the small intestine but as the age of the infection increases worm populations are highly aggregated in relation to the anterior sections of the small intestine. Individual worms are also shown to be aggregated with respect to each other. Between days 42 and 60 postinfection, although the pattern of distribution of N. dubius along the small intestine does not significantly change, survival of worms is influenced by both age and sex of ASH/CSI S.P.F. mice, reasons for which are discussed in the light of previous work on primary infections of N. dubius in other strains of laboratory mice

2000 ◽  
Vol 34 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Paul F. Brain ◽  
Tahia A. Maimanee ◽  
Maria Andrade

Juvenile and adult male and female Swiss mice in metabolism cages were fed one of four specially-formulated, pelleted diets containing respectively 8% saturated vegetable fat, 8% soya oil, 8% olive oil and 2% soya oil. The identities of the diets were hidden from the experimenter. Subjects were individually housed in metabolism cages and their consumption of food, growth and eliminative activities were measured. Clearly, these non-isocaloric diets differed in palatability, producing complex effects on growth as well as metabolic measures. Many indices were influenced by age, sex, and the duration of dietary exposure. Interactions between factors were common. Dietary fats appear to have subtle effects on the physiology and behaviour of rodents and may account for some differences between studies.


1980 ◽  
Vol 54 (2) ◽  
pp. 87-91 ◽  
Author(s):  
R. Beckett ◽  
A. W. Pike

ABSTRACTIncidence of mating pairs in 40 worm infections in 5 week old female CBA mice increased up to day 30 post infection. By this time, and thereafter until the experiment ended on day 70, approximately 60% of the worm population occurred as mating pairs. Mating began during the ontogenetic migration of the worms. There was no difference between the percentage of worms mating in the more highly populated anterior sections of the small intestine as compared to the less densely populated more posterior sections. Significantly more female than male worms were recovered between days 8 and 20 post infection (p<0.02 to 0.001) and there was a significant decline in overall recoveries during the experimental period (r = −0.77, p<0.01). Low intensity infections, with 4 to 16 worms per mouse, demonstrated that a larger percentage of worms in the infection were mating at an earlier time post infection than in the 40 worm infections. Ontogenetic migration was reduced in low intensity infections because the initial distribution of worms was more restricted.


Author(s):  
Maria Fitzgerald ◽  
Michael W. Salter

The influence of development and sex on pain perception has long been recognized but only recently has it become clear that this is due to specific differences in underlying pain neurobiology. This chapter summarizes the evidence for mechanistic differences in male and female pain biology and for functional changes in pain pathways through infancy, adolescence, and adulthood. It describes how both developmental age and sex determine peripheral nociception, spinal and brainstem processing, brain networks, and neuroimmune pathways in pain. Finally, the chapter discusses emerging evidence for interactions between sex and development and the importance of sex in the short- and long-term effects of early life pain.


Genetics ◽  
1984 ◽  
Vol 106 (1) ◽  
pp. 109-122
Author(s):  
Leif Andersson ◽  
Kaj Sandberg

ABSTRACT n the present study an extensive amount of data, comprising more than 30,000 offspring in total, was analyzed to evaluate the influence of age and sex on the recombination frequency in the K-PGD segment of the equine linkage group (LG) I and the influence of age, breed and sex on recombination in the Al-Es segment of LG II. A highly significant sex difference is reported for both segments. Male and female recombination values in the K-PGD segment were estimated at 25.8 ± 0.8 and 33.3 ± 2.5%, respectively. Similarly, recombination was less frequent in the male (36.6 ± 0.7%) than in the female (46.6 ± 1.2%) in the Al-Es segment. Comparison of data from two Swedish horse breeds revealed no significant breed differences in either sex for recombination in the Al-Es segment. No evidence of an age effect was found in any segment or sex. The distribution of individual male recombination estimates was also investigated, and a significant heterogeneity among stallions was revealed in the K-PGD segment. The results are discussed in relation to previous studies on factors affecting recombination in mammals.


2011 ◽  
Vol 88 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Sonia A. Cavigelli ◽  
Kerry C. Michael ◽  
Sheila G. West ◽  
Laura Cousino Klein

2011 ◽  
Vol 4 (2) ◽  
pp. 198 ◽  
Author(s):  
Sara Hashemi Shahraki ◽  
Abbass Eslami Rasekh

Slang usage in modern age Iran is a popular phenomenon among most male and female teenagers. How pervasive this variation of language use is among various age and sex groups in Iran has been a question of debate given the significance of religion in a theological system of social structure. The work presented in this study aims to investigate the effect of age and sex on variability of slang usage. Sixty Iranian participants were selected, and then were divided into three age groups (i.e. primary school, high school, and senior university students) each group consisting of ten males and ten females. A self-made questionnaire in the form of Discourse Completion Test (DCT) describing nine situations of friendly conversations was given to the participants. They were asked to make their choice on the responses, which ranged from formal to very informal style (common teenage slang expressions), or to write down what they wish to say under each circumstance. The results of the chi–square tests indicated that slang usage among high school students is more frequent as compared with other age groups. Unlike the popular belief suggesting that slang is used by boys rather than girls, the findings suggested that young Iranians both male and female use slang as a badge of identity showing their attachment to the social group they wish to be identified with.


2014 ◽  
Vol 24 (58) ◽  
pp. 197-204
Author(s):  
Juliana Carnevalli Siqueira Nery ◽  
Fabián Javier Marín Rueda

In this study, the relation of age and sex with visuospatial reasoning assessed by the Cube Test was investigated. In addition, a comparative study was conducted between this study sample and the normative group of the test with regard to visuospatial reasoning performance results. Six hundred and eighty-four students participated in this study, from the city of Belo Horizonte (State of Minas Gerais, Brazil), aged between 15 and 57 years old, both male and female. The results showed both age and sex differences, where younger students showed a significantly higher performance than older students and men showed significantly higher averages than women in every test comparison. In the study with the normative sample, men showed higher averages than women throughout every age group and in the overall result of both studies. The results obtained reflect those found in the literature and highlight the influence of age and sex on visuospatial reasoning.


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