Jak3 activation in human lymphocyte precursor cells

Although expression of the Jak3 tyrosine kinase in T lymphocytes has been thought to be restricted to mature, activated cells, mutations of Jak3 can lead to the development of a human severe combined immunodeficiency (SCID) characterized by an absence of peripheral T lymphocytes. We therefore examined in detail the expression of Jak3 throughout human T cell differentiation and show that Jak3 is in fact present throughout the entire developmental process, with high levels expressed in thymocytes. Jak3 is highly expressed in double negative (CD4⁻CD8⁻) cells, one of the earliest stages of thymocyte differentiation, and can be activated via the IL-7 receptor. IL-7 is known to stimulate thymocyte proliferation and initiate re-arrangement of the T cell receptor (TCR) β gene, suggesting that the failure of mutated Jak3 proteins to transduce this signal may be responsible for failures in T cell development. While Jak3 SCID patients possess mature peripheral B cells, we demonstrate that the Jak3 tyrosine kinase is also expressed in human pre-B cells and can be activated by the pre-B cell growth factor IL-7.     

Posttesticular development of spermatozoa of the tammar wallaby (Macropus eugenii)

Tammar wallaby spermatozoa undergo maturation during transit through the epididymis. This maturation differs from that seen in eutherian mammals because in addition to biochemical and functional maturation there are also major changes in morphology, in particular formation of the condensed acrosome and reorientation of the sperm head and tail. Of spermatozoa released from the testes, 83% had a large immature acrosome. By the time spermatozoa reached the proximal cauda epididymis 100% of sperm had condensed acrosomes. Similarly 86% of testicular spermatozoa had immature thumb tack or T shape head-tail orientation while only 2% retained this immature morphology in the corpus epididymis. This maturation is very similar to that reported for the common brush tail possum, Trichosurus vulpecula. However, morphological maturation occurred earlier in epididymal transit in the tammar wallaby. By the time spermatozoa had reached the proximal cauda epididymis no spermatozoa had an immature acrosome and thumbtack orientation. Associated with acrosomal maturation was an increase in acrosomal thiols and the formation of disulphides which presumably account for the unusual stability of the wallaby sperm acrosome. The development of motility and progressive motility of tammar wallaby spermatozoa is similar to that of other marsupials and eutherian mammals. Spermatozoa are immotile in the testes and the percentage of motile spermatozoa and the strength of their motility increases during epididymal transit. During passage through the caput and corpus epididymis, spermatozoa first became weakly motile in the proximal caput and then increasingly progressively motile through the corpus epididymis. Tammar wallaby spermatozoa collected from the proximal cauda epididymis had motility not different from ejaculated spermatozoa. Ultrastructural studies indicated that acrosomal condensation involved a complex infolding of the immature acrosome. At spermiation the acrosome of tammar wallaby spermatozoa was a relatively large flat or concave disc which projected laterally and anteriorly beyond the limits of the nucleus. During transit of the epididymal caput and proximal corpus the lateral projections folded inwards to form a cup like structure the sides of which eventually met and fused. The cavity produced by this fusion was lost as the acrosome condensed to its mature form as a small button-like structure contained within the depression on the anterior end of the nucleus. During this process the dorsal surface of the immature acrosome and its outer acrosomal membrane and overlying plasma membrane were engulfed into the acrosomal matrix. This means that the dorsal surface of the acrosomal region of the testicular tammar wallaby sperm head is a transient structure. The dorsal acrosomal surface of the mature spermatozoon appears ultrastructurally to be the relocated ventral surface of the acrosomal projections which previously extended out beyond the acrosomal depression on the dorsal surface of the nucleus of the immature spermatozoon.     

Seroprevalence of Toxoplasma gondii Infections in Pregnant Women in Gorgan City,Golestan Province,Northern Iran-2012

Background

Toxoplasma gondii is one of the most prevalent parasites of human and warm- blooded animals. Toxoplasmosis is important especially in two groups: pregnant women and immunocompromised patients. If women acquire the primary infection during the pregnancy, it would be life threatening or remains severe disorders for the fetus. This study was performed to evaluate the seroprevalence of T. gondii infection in pregnant women referred to Health Center in Gorgan City, Golestan Province, northern Iran.

Methods

Serum samples were collected from pregnant women referred to Health Center in Gorgan City, south eastern Caspian Sea. Anti- Toxoplasma IgG and IgM antibodies were determined by commercially ELISA kits and the relation of infection with socio-demographic and risk factors such as age, education, occupation, cat ownership, soil contact and some other factors was studied.

Results

From 555 tested sera of pregnant women referred to Health Center in Gorgan, 39.8% had IgG antibodies against T. gondii and 3.4% were positive for IgM antibodies. A significant correlation was seen between T. gondii infection with age and soil contact.

Conclusion

About 60% of pregnant women in Gorgan City are seronegative against T. gondii, so they should considered as at risk persons.     

Adverse Events Even after Percutaneous Coronary Intervention: Is There Any Way to Predict It?

Since its development, the frequency and indication of percutaneous coronary intervention (PCI) have been increasing tremendously. Although generally the procedure shows promising results, some patients still develop cardiovascular events even after PCI. Some risk prediction models have been developed in order to identify this group of patients who possess higher risk of developing cardiovascular events after PCI. This article discusses the available risk prediction models, the difference between risk prediction models, choosing risk prediction models, and also limitations of the available risk prediction models. (J Interven Cardiol 2010;23:86–94)