Adenovirus multiplication: inhibition by methisazone.

Methisazone (5 to 40 microM) inhibited the multiplication of types 3, 7, 9, 11, 14, 16, 17, 21, and 28 adenovirus; SV15 (a simian adenovirus) was also inhibited. A study of adenovirus 11 under single-cycle conditions showed that multiplication of the virus, was completely inhibited by 30 microM methisazone when addition of the compound was delayed until 13 hours after infection. A survey showed that the structure-activity relations of the action of methisazone against adenoviruses and pox viruses are similar.

Reappraisal of histologic features of the acute cutaneous graft-versus-host reaction based on an allogeneic rodent model.

We employed a rat model of complete major histocompatibility complex-mismatched allogeneic bone marrow transplantation to better characterize the histologic expression of the acute cutaneous graft-versus-host reaction (GVHR), compared with changes due to the preparative regimen. Cyclosporin A abolished the development of this GVHR. Low levels of dyskeratotic cells were present in all groups (allogeneic and syngeneic transplants with and without cyclosporin A) and, alone, were insufficient to diagnose a cutaneous GVHR. A consistent histologic feature of the GVHR was significant lymphoid infiltration of the dermis. The pattern of cytotoxic folliculitis involved follicular epithelium above the entry of sebaceous glands. Immunostain for major histocompatibility complex class II, IA, and IE antigens revealed that dendritic cells within the follicle were limited to this upper region and that lower follicular epithelium did not upregulate expression with evolution of the GVHR. Based on this model, we conclude 1) that the diagnostic scheme for the acute cutaneous GVHR should include lymphoid infiltration of the dermis, 2) that the preparative regimen (including total body irradiation) induces persistent low levels of dyskeratotic cells (two to three cells/linear mm of epidermis), and 3) that the pattern of follicular involvement may relate to the distribution of dendritic cells and to an inability of lower follicular epithelium to upregulate major histocompatibility complex class II antigens.

Acyclovir treatment of experimental herpetic keratitis in the rabbit eye.

In the rabbit eye model of experimental herpetic keratitis a satisfactory cure was obtained with ointments containing 1 percent, 2 percent, and 3 percent acyclovir, and also with idoxuridine. Trifluorothymidine and vidarabine were less effective in the particular conditions of the experiment. A cure was also obtained with acyclovir sodium salt injected intravenously, thus demonstrating that a local infection of the eye can be treated systematically.

Modifications on the heterocyclic base of acyclovir: syntheses and antiviral properties.

A group of compounds was prepared in which variations of the ring portion of the acyclovir (ACV) structure were made. These modifications included monocyclic (isocytosine, triazole, imidazole), bicyclic (8-azapurine, pyrrolo[2,3-d]pyrimidine, pyrazolo[3,4-d]pyrimidine) and tricyclic (linear benzoguanine) congeners. The derivatives were evaluated against herpes simplex virus type 1 (HSV-1) by the plaque-inhibition and plaque-reduction methods with only the 8-azapurine analogue 28 showing some activity. In a test measuring the ability of these compounds to inhibit the HSV-1 thymidine kinase, 28 and the tricyclic derivative 38 exhibited competition with ACV for binding to the enzyme. The inability of the group to exert significant antiherpetic action is attributed to their lack of phosphorylation to the requisite triphosphate stage.

Multiple methicillin-resistant Staphylococcus aureus strains as a cause for a single outbreak of severe disease in hospitalized neonates.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial infection. Outbreaks of infection caused by these pathogens are generally considered to be traceable to introduction of single strains into a hospital population. A large outbreak of bacteremic disease that recently occurred in our neonatal intensive care unit (11 episodes in 10 patients) involved 9 low birth weight infants and was associated with serious infection (4 episodes of meningitis). To determine the role of a single point source in this outbreak, isolates were characterized based on phenotypic and genotypic analyses. Phenotypic analysis included assessing hemolytic activity, phage typing, antimicrobial susceptibility testing and methicillin resistance population analysis. Genotypic analysis included assessment of plasmid profiles, dot-blot hybridization, restriction enzyme fragment pattern analysis and hybridization analysis of chromosomal DNA using a panel of staphylococcal gene probes. This analysis established that at least two distinct strains of MRSA were responsible for disease during this outbreak. This experience demonstrates the potential for MRSA to cause severe disease in the neonatal intensive care unit and indicates that the epidemiology of MRSA outbreaks is more complex than the spread of a single strain of bacteria.

A novel method for detecting the antiviral activity of flavans in their vapour phase.

This report describes a new method for detecting and measuring the antiviral activity of volatile compounds. This method, the vapour phase test, is a modification of the conventional plaque reduction test, in that the compounds instead of being incorporated in the overlay medium were deposited on the inner surface of the Petri dish lid. During the incubation period, the compounds (if volatile) permeated the overlay medium before exerting their antiviral effect. Compounds which have or may come to clinical trial against rhinovirus infections were compared by normal plaque reduction assays and by means of this new technique. Flavans were shown able to exert their antiviral activity in the vapour phase and thus display an advantage over non-volatile compounds. The report also briefly shows how the technique was used to evaluate the structure-activity relationships in a series of analogous compounds.

The relative potencies of anti-influenza compounds.

The relative potencies of some standard anti-influenza compounds have been examined in vitro by plaque reduction in calf kidney cells, and in vivo by reduction in virus titers of the lungs of infected mice. Strains belonging to the four subtypes H0N1, H1N1, H2N2, and H3N2 were employed to compare the activity of amantadine hydrochloride and ribavirin. In vitro for all strains except A/NWS/OO(H0N1) amantadine hydrochloride was 3-4 times more active than ribavirin. In vivo with sensitive strains amantadine hydrochloride produced a plateau effect at higher dose levels, but at lower dose levels was marginally more active than ribavirin. The sensitivity of A/Hong Kong/1/68 (H3N2) to amantadine hydrochloride, rimantadine hydrochloride, cyclooctylamine, and ribavirin was also investigated. In vitro rimantadine hydrochloride was similar in activity to amantadine hydrochloride and ribavirin, but cyclooctylamine was considerably less active. In vivo cyclooctylamine was active only at 150 mg/kg/day, whereas rimantadine hydrochloride produced a plateau effect over a range of concentrations from 9,12-150 mg/kg/day.

Relative potencies of anti-herpes compounds.

Assessment of the relative potencies of compounds that inhibit the multiplication of herpesvirus is rendered difficult by the fact that they have been investigated by different workers who were not using comparable test systems. The relative and absolute potencies of idoxuridine, cytarabine, vidarabine, trifluorothymidine, and ara-DAP have therefore been evaluated by plaque inhibition, plaque reduction, and yield reduction tests, the most satisfactory dose-response lines being obtained by plaque reduction. The results obtained for five strains of type 1 and five of type 2 herpesvirus indicated that cytarabine was the most active compound, followed by idoxuridine and trifluorothymidine; vidarabine and ara-DAP were found to be the least active compounds. From comparisons of ED50 values derived from the dose-response lines it was found that the greater sensitivity of type 1 strains reported in the literature could only be confirmed with idoxuridine, since considerable overlaps in type sensitivity were observed with the other compounds.

Histologic comparison of autologous graft-vs-host reaction and cutaneous eruption of lymphocyte recovery.

BACKGROUND AND DESIGN: The cutaneous eruptions due to allogeneic graft-vs-host disease, autologous graft-vs-host disease, and lymphocyte recovery occur in the setting of peripheral leukocyte reconstitution after marrow aplasia. Since the eruptions of lymphocyte recovery (ELR) and autologous graft-vs-host disease develop in the presence of histocompatibility, we question whether reliable histologic differentiation is possible. To this end, we performed a retrospective, blind analysis of 38 skin biopsy specimens obtained from patients who received autologous marrow transplants or intensive chemotherapy alone for various malignant neoplasms. RESULTS: In 31% of the cases, we were unable to distinguish between an ELR and a grade 2 graft-vs-host reaction. In 40% of the ELR specimens, a significant number of dyskeratotic keratinocytes were present, leading to the false interpretation of a grade 2 graft-vs-host reaction. Satellite cell necrosis was observed in both groups. The patterns of dyskeratotic keratinocytes were similar; one ELR specimen displayed prominent follicular involvement. Most ELR specimens were consistent with grade 1 graft-vs-host reaction changes. CONCLUSIONS: These findings indicate that the presence of dyskeratotic keratinocytes is not specific for a graft-vs-host reaction and that cutaneous eruptions after autologous marrow transplantation are best considered an ELR.

Treatment of experimental herpes simplex keratitis with acycloguanosine.

Acycloguanosine, a recently developed compound with high inhibitory activity against viruses belonging to the herpes group, has been evaluated in experimental herpes simplex keratitis in rabbits in comparison with trifluorothymidine and preparations of idoxuridine and vidarabine at present in clinical use. All compunds were used in the form of ophthalmic ointments which were applied 5 times a day at intervals of 2 hours. Treatment began on the third day of infection and was continued for 4 days. Complete cure was obtained with acycloguanosine and idoxurdine; trifluorothymidine and vidarabine were considerably less effective. Acycloguanosine was equally effective when given intravenously in the form of its sodium salt, and could be detected in the tear fluid in inhibitory concentrations when given by mouth. The compound was relatively free from toxicity.

Elevated peripheral neutrophils and matrix metalloproteinase 9 as biomarkers of functional outcome following subarachnoid hemorrhage.

There is growing evidence supporting the role of inflammation in early brain injury and cerebral vasospasm following subarachnoid hemorrhage (SAH). Matrix metalloproteinases (MMPs) are released by inflammatory cells and can mediate early brain injury via disruption of the extracellular matrix and mediate vasospasm by cleaving endothelin-1 into vasoactive fragments. We hypothesize that inflammation marked by neutrophil elevation and MMP-9 release in human SAH is associated with vasospasm and with poor clinical outcome. We enrolled consecutive SAH subjects (N = 55), banked serial blood and cerebrospinal fluid (CSF) samples, and evaluated their 3-month modified Rankin scores (mRS). Vasospasm was defined as >50% vessel caliber reduction on angiography 6-8 days post-SAH. A poor outcome was defined as mRS > 2. We compared blood leukocyte and neutrophil counts during post-SAH days 0-14 with respect to vasospasm and 3-month outcome. In a subset of SAH subjects (N = 35), we compared blood and CSF MMP-9 by enzyme-linked immunosorbent assay (ELISA) on post-SAH days 0-1, 2-3, 4-5, 6-8, and 10-14 with respect to vasospasm and to 3-month outcome. Persistent elevation of blood leukocyte (p = 0.0003) and neutrophil (p = 0.0002) counts during post-SAH days 0-14 are independently associated with vasospasm after adjustment for major confounders. In the same time period, blood neutrophil count (post-SAH days 2-3, p = 0.018), blood MMP-9 (post-SAH days 4-5, p = 0.045), and CSF MMP-9 (post-SAH days 2-3, p = 0.05) are associated with poor 3-month SAH clinical outcome. Neutrophil count correlates with blood MMP-9 (post-SAH days 6-8, R = 0.39; p = 0.055; post-SAH days 10-14, R = 0.79; p < 0.0001), and blood MMP-9 correlates with CSF MMP-9 (post-SAH days 4-5, R = 0.72; p = 0.0002). Elevation of CSF MMP-9 during post-SAH days 0-14 is associated with poor 3-month outcome (p = 0.0078). Neither CSF nor blood MMP-9 correlates with vasospasm. Early rise in blood neutrophil count and blood and CSF MMP-9 are associated with poor 3-month SAH clinical outcome. In blood, neutrophil count correlates with MMP-9 levels, suggesting that neutrophils may be an important source of blood MMP-9 early in SAH. Similarly, CSF and blood MMP-9 correlate positively early in the course of SAH, suggesting that blood may be an important source of CSF MMP-9. Blood and CSF MMP-9 are associated with clinical outcome but not with vasospasm, suggesting that MMP-9 may mediate brain injury independent of vasospasm in SAH. Future in vitro studies are needed to investigate the role of MMP-9 in SAH-related brain injury. Larger clinical studies are needed to validate blood and CSF MMP-9 as potential biomarkers for SAH outcome.

The reproductive effects of beta interferon therapy in pregnancy: a longitudinal cohort.

OBJECTIVE: To determine whether interferon therapy during human pregnancy increases reproductive risks in women. METHODS: This longitudinal, controlled cohort study consisted of three groups of women: an exposed group, a disease matched unexposed group, and a healthy comparative group. Subjects were selected from women contacting the Motherisk Program regarding maternal beta interferon exposure, mostly for multiple sclerosis during pregnancy, from 1997 to 2004. After delivery all of the women were re-contacted for a follow-up interview regarding maternal health, pregnancy outcome, and neonatal health. RESULTS: The study group (n = 16 women, 23 pregnancies) were exposed to interferon beta-1a (Avonex, Rebif) and interferon-1b (Betaseron). There was a decrease in mean birth weight in the exposed group (3,189 +/- 416 g) as compared to healthy controls (3,783 +/- 412 g, p = 0.002). Women exposed to beta interferon had a higher rate of miscarriages and stillbirths (39.1%) vs healthy controls (5%) (p = 0.03), even after correction for potential confounders. There were two major malformations (abnormality in the X chromosome, Down's syndrome) among exposed fetuses. CONCLUSIONS: Beta interferon therapy in the first trimester of pregnancy appears to be associated with an increased risk for fetal loss and low birth weight.

Successful treatment of experimental B virus (Herpesvirus simiae) infection with acyclovir.

The efficacy of the new nucleoside analogue acyclovir against B virus (Herpesvirus simiae) was investigated in rabbits and Vero cells infected with 2-136 and 0.3-1.0 TCD50 of the virus respectively. In the Vero cells 1 mg of acyclovir/1 reduced the yield of virus by 90%, which was slightly less than the effect on herpes simplex virus. Results in the rabbits varied with the interval between doses, duration of treatment, and delay before starting treatment. Acyclovir controlled an otherwise lethal infection when given not less than eight-hourly for 14 days. Withdrawing treatment after 9-10 days resulted in late-onset fatal disease in some rabbits. Treatment begun within 24 hours after infection gave complete protection, and rabbits first treated up to five days after infection showed a significant reduction in mortality (p less than 0.001). The plasma half life of acyclovir is twice as long in man as in rabbits and progression of the disease is much slower. Hence acyclovir may be useful for post-exposure prophylaxis against B virus infection in man and possibly also for treatment of the disease.

9-(2-hydroxyethoxymethyl) guanine activity against viruses of the herpes group.

Of a series of nucleoside analogues synthesised, 9-(2-hydroxyethoxymethyl) guanine was found to have marked antiviral activity in animal models of herpes virus infections, associated with very low toxicity.