Chemoprotective effect of Spirulina (Arthrospira) against cyclophosphamide-induced mutagenicity in mice.

The aim of this study was to investigate the antimutagenic effects of Spirulina (SP) on male and female mice by the dominant lethal test using cyclophosphamide (CP) as a mutagen. Animals of both sex were given SP orally at 0, 200, 400 or 800 mg/kg body weight (b.w.) for 2 weeks prior to starting the CP treatment. CP was i.p. injected daily for 5 days at 40 mg/kg b.w. For the male-dominant lethal test, each male was caged with untreated females per week for 3 weeks. For the female-dominant lethal test the above doses and schedule treatments were used and treated females were caged for one week with untreated males (1-2). On days 13-15 after breeding was |started all the females were evaluated for incidence of pregnancy, total corpora lutea, total implants and pre- and post-implant losses. In the male-dominant lethal test, the CP induced pre- and post-implant losses in untreated females were inhibited at all SP doses. In the female-dominant lethal test only post-implantation losses were prevented at the same doses. Semen examination of a separate group of mice showed that SP improved its quality. Our results illustrate protective effects of SP in relation to CP-induced genetic damage to germ cells.

[Molecular biology of pathogenesis by herpesvirus]. / Biología molecular de la patogénesis por herpesvirus.

A distinguishing feature of Herpes simplex virus (HSV) infections is the ability of these viruses to persist for long periods in their host in nonreplicative or latent state. The study of pathogenesis of herpesvirus infections can be divided in: acute viral replication, establishment of latency, maintenance of latency and reactivation. In this paper we analyzed the viral genetic information which was identified as essential or very important for such events.

Effect of dsRNA from phi 6 bacteriophage on herpetic infection in cell culture and an animal model.

The double-stranded (ds) RNA from phi 6 bacteriophage inhibited herpes simplex virus type 1 (HSV-1) and HSV-2 infection in MA-104 cells but not in Vero cells. HSV-2 was more sensitive to this effect than HSV-1, with the HSV-2 ED50 being 0.25 micrograms/ml and the HSV-1 ED50 1.68 micrograms/ml. On genital infection by HSV-2 in guinea pigs, phi 6 dsRNA was more effective by intravaginal (P less than 0.05) than by intraperitoneal administration. A single dose of dsRNA of 600 micrograms/kg by intravaginal route modified favorably the natural course of the genital herpes in the treated animals (p less than 0.001). Compared with the infected controls, they showed a faster recovery with better healing of lesions; and the number and severity of recurrence was low. No mortality was observed and the control infected animals showed a mortality of 39%. Sera from dsRNA-treated animals showed antiviral activity with a 50% plaque-depressing dose (PDD50) of 10(1.5)/150 microliters; no antiviral activity was found in sera either from control infected or uninfected animals. No adverse effect was observed on the rate of growth of uninfected dsRNA-treated controls.

Short electropherotype rotaviruses isolated longitudinally from a cohort of Mexican infants.

Stool specimens obtained longitudinally during the first year of life of a cohort of 75 rural infants were tested for the presence of rotavirus with an enzyme-linked immunosorbent assay. Thirty four infants showed the presence of rotaviruses during the first year of life. Only 41% of these episodes were associated with diarrhea. Extraction of rotavirus RNA was still possible in 12 of 34 stool samples, ten of them obtained during episodes of associated-diarrhea. Electropherotyping of these rotavirus showed that nine had a short electropherotype. One diarrheal and two asymptomatic samples had a long electropherotype. Subgrouping the viruses with monoclonal antibodies showed that five of the nine rotaviruses with short electropherotype belonged to subgroup I, and two of the three with long electropherotype belonged to subgroup II. The rest of rotaviruses could not be subgrouped. This study confirms the prevalence of only few rotavirus strains in any defined geographic region over a specific period of time, in this case, a rotavirus with a short electropherotype.

A 65-kDa trypsin-sensible membrane cell protein as a possible receptor for dengue virus in cultured neuroblastoma cells.

Dengue virus infects primary neurons in mouse experimental model and tissue culture cells of the central nervous system (CNS). In the present work, a mouse neuroblastoma cell line (N1E-115) and a human neuroblastoma cell line (SK-N-SH), susceptible to dengue virus infection were used to study the presence of cell membrane receptor for dengue-2. By day 5 postinfection (pi), viral antigen was detected by immunofluorescence in the cytoplasm and surrounding the nucleus of N1E-115 cells, while on day 7 pi, it was also present along neural extensions. Infection of N1E-115 cells was diminished with trypsin treatment but not with neuraminidase or endoglycosidase H. Partially purified cell membrane proteins from neuroblastoma cells were analyzed by the Virus Overlay Protein Blot Assay (VOPBA), and a single band migrating at 65 kDa was detected in mouse and human neuroblastoma cells but not in C6, a non-susceptible rat glial cell line which was included as a negative control. The 65 kDa protein was eliminated only when nitrocellulose membranes were treated with trypsin. Analysis of neuronal cell infection by dengue virus provides a useful tool to understand the nature of cellular receptors and mechanisms involved in the infection of the nervous system by dengue viruses.