PubMed · 8657231
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S D Shafran. 1996-07-18. Herpes simplex encephalitis.. https://doi.org/10.1056/nejm199607183350316
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The sugar moiety of nucleosides in solution is known to exist in a rapid dynamic equilibrium between extreme Northern and Southern conformations as defined in the pseudorotational cycle. In the present work, we describe how the bicyclo[3.1.0]hexane template fixes the ring pucker of 2'-deoxy-methanocarba-nucleosides 1-5 and 12 to values corresponding to either one of these two extreme conformations that are typical of nucleosides. The syntheses of the fixed Northern conformers 1-5 were performed by Mitsunobu coupling of the heterocyclic bases with the chiral carbocyclic alcohol 6 [(1R,2S,4R,5S)-1-[(benzyloxy)methyl]-2-(tert-butyloxy)-4-hydrox ybicyclo[3.1.0]hexane], while the synthesis of the Southern conformer, (S)-methanocarba-T (12), was reported earlier. Carbocyclic thymidine (carba-T, 13) was used as a reference, flexible carbocyclic nucleoside. Antiviral evaluation of these compounds revealed a very potent antiherpetic activity associated with the Northern thymidine analogue 2, which was more powerful than the reference standard acyclovir against both HSV-1 and HSV-2. (N)-Methanocarba-T (2) was further evaluated as a component of a short oligodeoxynucleotide (ODN) phosphorothioate (5'-CTTCATTTTTTCTTC-3') where all thymidines were replaced by 2. The expected thermodynamic stability resulting from the preorganization of the pseudosugar rings into a Northern conformation, typical of A-DNA, was evident by the increase in Tm of the corresponding DNA/RNA heteroduplex. However, the rigid A-tract ODN caused loss of RNase H recruitment. A detailed conformational analysis of (N)-methanocarba-T (2) and (S)-methanocarba-T (12), as representative examples of conformationally rigid pseudorotational antipodes, revealed that in addition to their different forms of ring pucker, (S)-methanocarba-T appears to be a rather stiff molecule with fewer low-energy conformational states available compared to (N)-methanocarba-T. The syn/anti-energy barrier for these nucleoside analogues is 5-6 kcal/mol higher than for common nucleosides.
OBJECTIVE: To determine the effect of acyclovir and prednisone treatment of herpes zoster on chronic pain and quality-of-life outcomes. DESIGN: Randomized, double-blind, placebo-controlled study with a 2 x 2 factorial design. SETTING: 15 university hospitals or affilliated clinics. PATIENTS: 208 immunocompetent patients older than 50 years of age who had localized herpes zoster that developed less than 72 hours before study enrollment. INTERVENTION: Acyclovir or a matched placebo was administered orally, 800 mg five times daily, for 21 days. Prednisone or a matched placebo was administered orally at 60 mg/d for the first 7 days, 30 mg/d for days 8 to 14, and 15 mg/d for days 15 to 21. The four treatments regimens given were acyclovir plus prednisone; acyclovir plus prednisone placebo; prednisone plus acyclovir placebo; and placebos for both acyclovir and prednisone. MEASUREMENTS: Patients were monitored daily for the first 28 days for lesion healing, resolution of pain, return to usual activity, and return to uninterrupted sleep. Monitoring was then done monthly for 6 months. Patients documented analgesic requirements each day, and adverse events and laboratory abnormalities were recorded at each clinical visit. An intention-to-treat analysis was used. RESULTS: Patients were randomly allocated to receive one of the four regimens. Demographic characteristics were similar for each group. Time to total crusting and healing was accelerated for patients receiving acyclovir plus prednisone compared with patients receiving two placebos; the risk ratios were 2.27 (95% Cl, 1.46 to 3.55) for total crusting and 2.07 (Cl, 1.26 to 3.38) for healing. Similarly, compared with the placebo group, patients receiving acyclovir plus prednisone had accelerated time to cessation of acute neuritis (risk ratio, 3.02 [Cl, 1.42 to 6.41]), time to return to uninterrupted sleep (risk ratio, 2.12 [Cl, 1.25 to 3.58]); time to return to usual daily activity (risk ratio, 3.22 [Cl, 1.92 to 5.40]); and time to cessation of analgesic therapy (risk ratio, 3.15 [Cl, 1.69 to 5.89]). In the acyclovir plus prednisone group, resolution of pain during the 6 months after disease onset did not statistically differ from that in the other groups. No important clinical or laboratory adverse events occurred in any group. CONCLUSIONS: In relatively healthy persons older than 50 years of age who have localized herpes zoster, combined acyclovir and prednisone therapy can improve quality of life.
These recommendations represent the first statement by the Advisory Committee on Immunization Practices (ACIP) on the use of live, attenuated varicella virus vaccine--VARIVAX--manufactured by Merck and Company, Inc. and licensed in March 1995 for use in healthy persons > or = 12 months of age. In addition to presenting information regarding vaccine, this statement updates previous recommendations concerning the use of varicella zoster immune globulin (VZIG) as prophylaxis against varicella (MMWR 1984; 33:84-90, 95-100).