Acyclovir is an effective antiviral drug that selectively inhibits herpes virus replication. It is phosphorylated by viral thymidine kinase to a triphosphate, which inhibits the DNA polymerase and thus the formation of viral DNA. Host cells are not significantly affected by acyclovir. Herpes simplex viruses are more sensitive to acyclovir than are varicella-zoster viruses. Resistant herpes viruses, that lack the thymidine kinase, have been observed almost exclusively in immunocompromised subjects (Collins et al. 1989).

The effect that prenatal exposure of rats to acyclovir has on immune system development was examined by Stahlmann et al. (1992). Pregnant Wistar rats were exposed to 100 mg acyclovir/kg body wt either with one or three (i.e., 1x100 and 3x100, respectively) s.c. injections on GD 10. There was considerable mortality during the first week after birth of pups from dams given 3x100 mg acyclovir/kg. Body weights of 12-week-old offspring born to dams exposed to 3x100 were reduced by 12.5 to 18.8% compared to controls for males and females respectively. Thymus and liver weights were also reduced by 22.1% to 35.5% and 8.8% to 11.6%, respectively, in both male and female offspring compared with controls.

Offspring were infected with T. spiralis at 6 weeks of age and assessed for host resistance to this parasitic nematode. Host resistance was evaluated by titration of Ig isotype antibody responses to T. spiralis antigen in offspring as well as determination of muscle T. spiralis larvae burdens. IgG, IgA and IgE anti-T. spiralis antibody titers were suppressed in 8- to 12-week-old 3x100 prenatally acyclovir-exposed offspring. The number of T. spiralis larvae in tongue muscle was significantly increased compared to that of controls. These results indicate that prenatal acyclovir exposure results in a long lived or "persistent" decrease in T. spiralis-specific Ig isotype antibodies and decreased resistance to T. spiralis infection (Stahlmann et al. 1992).

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Free Yourself from Panic Attacks

Free Yourself from Panic Attacks

With all the stresses and strains of modern living, panic attacks are become a common problem for many people. Panic attacks occur when the pressure we are living under starts to creep up and overwhelm us. Often it's a result of running on the treadmill of life and forgetting to watch the signs and symptoms of the effects of excessive stress on our bodies. Thankfully panic attacks are very treatable. Often it is just a matter of learning to recognize the symptoms and learn simple but effective techniques that help you release yourself from the crippling effects a panic attack can bring.

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