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Biomedical subjects

S Grill

Publications and source records attributed to S Grill.

27 records · Page 2Linked to original sources

Acetylenic nucleosides. 4. 1-beta-D-arabinofuranosyl-5-ethynylcytosine. Improved synthesis and evaluation of biochemical and antiviral properties.

5-Ethynyl-1-beta-D-arabinofuranosylcytosine (EAC) was prepared from 1-(2,3,5-tri-O-acetyl-beta-D-arabinofuranosyl)cytosine by iodination followed by coupling with (trimethylsilyl)acetylene and deblocking. At 50 microM, EAC was found to inhibit the in vitro replication of herpes simplex virus type 1 and type 2 by greater than 99%. EAC also showed activity against a strain of HSV-1 resistant to (E)-5-(2-bromovinyl)-2'-deoxyuridine which has an alteration of the virus-induced thymidine kinase (TK). At 100 microM, EAC did not inhibit the in vitro growth of leukemia L1210 and HeLa cells. EAC was resistant to the action of dCR-CR deaminase, its rate of deamination being approximately 2% that of dCR. The compound was a poor substrate for dCR kinase, but it was phosphorylated by HSV-1- and HSV-2-induced TKs at 50% and 30%, respectively, the rate of thymidine.

Antiviral Agents↗

Mode of action of phosphonoformate as an anti-herpes simplex virus agent.

Phosphonoformate inhibited the replication of Herpes simplex virus (HSV) type 1 and type 2 in culture. The concentration required to inhibit the replication of both types of virus by 2 logs at 28 h post-infection was approximately 150 microM. It was more potent than phosphonoacetate against the growth of both virus types. A virus mutant which is resistant to phosphonoacetate was cross-resistant to phosphonoformate. Arsonoacetate, at 300 microM, had no antivirus activity. Phosphonoformate also inhibited HeLa and KB cell growth; at a concentration of about 500 microM, cell growth was inhibited by 50%. The anti-cell growth effects of the drug were completely reversible. The antivirus effect of phosphonoformate was partially reversible, depending on the time and duration of exposure of infected cultures to the drug. To obtain the maximum antivirus effect, phosphonoformate had to be added within the first 3 h post-virus-infection and be continuously present for at least 18 h. Phosphonoformate, added at 0 h post-infection, suppressed the induction of virus-specific DNA polymerase and DNAase activities. dTMP incorporation into DNA was preferentially inhibited in nuclei isolated from infected cells compared to uninfected cells, and the degree of inhibition varied with the ionic strength of the assay. Phosphonoformate was a potent inhibitor of the purified HSV-1 and HSV-2 DNA polymerases, inhibiting DNA polymerase activity by 50% at a concentration of 3 microM and ionic strength of 0.2.

Antiviral Agents↗

Anti-herpes simplex virus and anti-human cell growth activity of E-5-propenyl-2'-deoxyuridine and the concept of selective protection in antivirus chemotherapy.

E-5-Propenyl-2'-deoxyuridine (E-5-propenyl-dUrd) inhibited the growth of herpes simplex virus (HSV) types 1 (HSV-1) and 2 in culture. The concentration of drug required to give a 2-log reduction in virus titer was 5 microM for HSV-1 and 23 microM for HSV-2. The anti-HSV-1 activity of this agent was more potent than 5-propyl-dUrd, equivalent to E-5(3,3,3-trifluoropropenyl)-dUrd, and less potent than E-5-bromovinyl-dUrd. The HSV-1 mutant (B2006) lacking the ability to induce virus-specific thymidine kinase could not be inhibited by E-5-propenyl-dUrd. The binding constants of E-5-propenyl-dUrd to HSV-1, HSV-2, varicella-zoster virus, and human mitochondrial thymidine kinases were established to be 0.2, 6.2, 0.3, and 0.8 microM, respectively. Thymidine phosphorylation catalyzed by human cytosol thymidine kinase could not be inhibited by E-5-propenyl-dUrd at a concentration 10-fold higher than the thymidine in the assay. When thymidine and E-5-propenyl-dUrd were added concomitantly at equal concentrations to virus-infected cells, the antiviral activity was not reversed in HSV-1 and only partially reversed in HSV-2. E-5-Propenyl-dUrd also inhibited the growth of human cells in culture with 50% inhibitory dose of 50 microM. Since this inhibition could be readily reversed by a lower concentration of thymidine, the idea of selective protection is proposed. This approach could avoid the cytotoxic effect of an antiviral agent with properties similar to E-5-propenyl-dUrd without sacrificing antiviral activity.

Antiviral Agents↗

Postural instability in Parkinson's disease.

Persons with Parkinson's disease are at great risk of suffering traumatic injuries from falls. Intervention with physical therapy and the use of assistive devices are helpful in preventing falls. Unfortunately, many patients are not referred for these interventions until they have already suffered traumatic injury. A simple measure of balance, which can easily be performed in an office setting, is the functional reach. This measure has been shown to be predictive of falls in the elderly. In this study, the functional reach was measured in patients with idiopathic Parkinson's disease during each visit over at least one year. Patients deemed at risk of falling were referred for physical therapy and possibly assistive devices. Those patients subsequently suffering falls were noncompliant with the recommendations.

Accidental Falls↗

[The use of buprenorphine in the postoperative period in heart surgery. Evaluation of its efficacy and tolerance].

Twenty patients were studied in the early post-operative period after cardiac surgery with sternotomy. Buprenorphine was prescribed: 0.3 mg intra-muscularly after total recovery from anaesthesia (8th hour) then every 8 hours if requested during 72 hours. The patients auto-estimated their level of analgesia, the clinical effects were measured with regard to heart rate, systolic and diastolic arterial pressure, and respiratory rate, before, 2 and 4 hours after each injection. Buprenorphine administration produces an effective, long lasting (8 to 12 hours) analgesia. No significant changes in haemodynamic or respiratory parameters were noticed. Side effects occurred rarely: 5 cases of drowsiness, reversible by verbal stimulation, 2 of nausea and sweats, 2 retentions of urine (after vesical catheter withdrawal). Parenteral buprenorphine is satisfactory for treatment of severe thoracic pain due to sternotomy, although the oral route would be safer during effective anticoagulant treatment.

Adolescent↗