Drugs online research references








Antiviral Res. 1995 Jun;27(3):271-9.
Inhibitory action of acyclovir (ACV) and penciclovir (PCV) on plaque formation and partial cross-resistance of ACV-resistant varicella-zoster virus to PCV.

Hasegawa T, Kurokawa M, Yukawa TA, Horii M, Shiraki K.

Department of Virology, Toyama Medical and Pharmaceutical University, Japan.

Penciclovir has potent antiviral activity against varicella-zoster virus (VZV). We have characterized the inhibitory effects of penciclovir and acyclovir on the plaque formation of cell-free VZV and cross-resistance of acyclovir-resistant VZV to penciclovir. The apparent effective concentration for 50% plaque reduction (EC50) of penciclovir determined on the third day was significantly lower than that determined on the fourth or fifth day. The size of plaques was smaller in the presence of penciclovir than in the presence of acyclovir. The effective concentrations for 50% reduction of the number of infected cells per plaque were 1.40 and 5.00 micrograms/ml for penciclovir and acyclovir, respectively. Thus penciclovir suppressed spread of infection within developing plaques more efficiently than acyclovir. Five acyclovir-resistant VZV strains with altered DNA polymerase selected by acyclovir were examined for cross-resistance to penciclovir. They were 11- to 18-fold more resistant to ACV than the parent strain, but only 4- to 5-fold more resistant to PCV. Penciclovir-triphosphate carrying the 3'-hydroxyl group of 2'-deoxyribose might have better affinity to the altered viral DNA polymerase than acyclovir-triphosphate without the 3'-hydroxyl group.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8540749&dopt=Abstract




Zhonghua Yi Xue Za Zhi. 2001 Aug 25;81(16):1004-7.
[Anti-hepatitis B virus effects of lamivudine and other five drugs in vitro]

[Article in Chinese]

Cao H, Tao P.

Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China.

OBJECTIVE: To find out reliable index for evaluating the anti-hepatitis B virus (HBV) effects in vitro of lamivudine (3TC) and other five anti-HBV drugs. METHODS: The contents of human hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus DNA (HBV DNA) in the culture supernatant of 2.2.15 cell line transfected with hepatitis B virus gene were tested after the six anti-hepatitis B virus drugs were added respectively, and the accordance of different indexes was compared. RESULTS: All six drugs, within a certain range, exercised only weak or no inhibitive effect on extracellular HBsAg and HBeAg secreted by 2.2.15 cell line. Lamivudine and 2 3-dideoxy-3-fluoroguanosine (FLG) significantly inhibited the level of HBV DNA, with the 50% inhibition concentration(IC50) of 0.31 mumol/L and 0.53 mumol/L respectively. Acyclovir (ACV) and interferon-alpha(IFN-alpha) also inhibited the HBV DNA with the IC50 of 0.33 mmol/L and 96.18 U/ml respectively. Phosphonoformate (PFA) and ribavirin (RBV) showed none effect on HBV DNA content even at the maximum non-toxic concentrations. CONCLUSION: There is not accordance between the expression activities of proteins of HBsAg and HBeAg and the inhibition of HBV DNA level. HBV DNA level better reflexes the inhibitive effect of different drugs and can be used as an important index for evaluation of anti-HBV effect in vitro.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11718074&dopt=Abstract




Invest Ophthalmol Vis Sci. 1993 Nov;34(12):3459-65.
Prophylactic acyclovir effectively reduces herpes simplex virus type 1 reactivation after exposure of latently infected mice to ultraviolet B.

Blatt AN, Laycock KA, Brady RH, Traynor P, Krogstad DJ, Pepose JS.

Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110.

PURPOSE. To determine the potential efficacy and anatomic sites of action of prophylactic oral acyclovir using a murine model of ultraviolet-B-induced reactivation of herpes simplex 1 keratitis. METHODS. Latent infection with herpes simplex 1 (McKrae) was established in 80 National Institutes of Health inbred strain of mice. Forty of the mice were given acyclovir orally and the other 40 latently infected mice served as controls. Mice were exposed to 250 mJ/cm2 of ultraviolet-B radiation and killed on days 1, 2, 3, and 4 after ultraviolet-B radiation. Trigeminal ganglia and eyes from these mice were homogenized and incubated on Vero cell monolayers for recovery of reactivated virus. RESULTS. Based on the recovery of infectious virus after ultraviolet-B in treated versus control groups, acyclovir effectively reduced detectable viral reactivation at both the ocular level (P = 0.003) and the ganglionic level (P = 0.025). The numbers of viral culture-positive eye and trigeminal ganglia homogenates in the control group were 11 and 6 out of 40, respectively, compared to 1 and 0 out of 40 culture-positive eye and trigeminal ganglia homogenates in the acyclovir treated mice. Therapeutic serum levels of acyclovir were confirmed by high performance liquid chromatography. In the acyclovir-tested group, the single case of viral break-through at the ocular surface was not an acyclovir-resistant mutant. CONCLUSION. Prophylactic acyclovir effectively reduces the incidence of herpes simplex virus-1 reactivation after ultraviolet-B-induced reactivation in National Institutes of Health inbred strain of mice.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8225880&dopt=Abstract












online pharmacies || Hair Million herbal formula for hair loss and hair growth || Tramadol || Antibiotics and prescription medications online literature || Antibiotics