Biology of retroviruses: detection, molecular biology, and treatment of retroviral infection

Detection and identification of cancerous murine fibroblasts, transformed by murine sarcoma virus in culture, using Raman spectroscopy and advanced statistical methods

BACKGROUND

Cancer is one of the leading worldwide causes of death. It may be induced by a variety of factors, including carcinogens, radiation, genetic factors, or DNA and RNA viruses. The early detection of cancer is critical for its successful therapy, which can result in complete recovery from some types of cancer.

METHODS

Raman spectroscopy has been widely used in medicine and biology. It is a noninvasive, nondestructive, and water-insensitive technique that can detect changes in cells and tissues that are caused by different disorders, such as cancer. In this study, Raman spectroscopy was used for the identification and characterization of murine fibroblast cell lines (NIH/3T3) and malignant fibroblast cells transformed by murine sarcoma virus (NIH-MuSV) cells.

RESULTS

Using principal component analysis and LDA it was possible to differentiate between the NIH/3T3 and NIH-MuSV cells with an 80-85% success rate based on their Raman shift spectra.

CONCLUSIONS

The best results for differentiation were achieved from spectra that were obtained from the rich membrane sites.

GENERAL SIGNIFICANCE

Because of its homogeneity and complete control of most factors affecting its growth, cell culture is a preferred model for the detection and identification of specific biomarkers related to cancer transformation or other cellular modifications.

Antiviral Activities of Polysaccharides from Natural Sources

The ever increasing resistance of human pathogens to current anti-infective agents is a serious medical problem, leading to the need to develop novel antibiotic prototype molecules. In the case of viruses, the search for antiviral agents involves additional difficulties, particularly due to the nature of the infectious viral agents. Thus, many compounds that may cause the death of viruses are also very likely to injure the host cell that harbours them. Natural products are increasingly appreciated as leads for drug discovery and development. Screening studies have been carried out in order to find antiviral agents from natural sources, and the occurrence of antiviral activity in extracts of plants, marine organisms and fungi is frequent. The evidence indicates that there may be numerous potentially useful antiviral phytochemicals in nature, waiting to be evaluated and exploited. In addition, other plants, not previously utilized medicinally, may also reveal antivirals. Among natural antiviral agents, recent investigations have reconsidered the interest of phyto-polysaccharides, which act as potent inhibitors of different viruses. This chapter will illustrate a variety of antiviral polysaccharides from natural sources since 1990, with the aim of making this matter more accessible to drug development

Anti-viral activity of red microalgal polysaccharides against retroviruses

Red microalgal polysaccharides significantly inhibited the production of retroviruses (murine leukemia virus- MuLV) and cell transformation by murine sarcoma virus(MuSV-124) in cell culture. The most effective inhibitory effect of these polysaccharides against both cell transformation and virus production was obtained when the polysaccharide was added 2 h before or at the time of infection. Although, addition of the polysaccharide post-infection significantly reduced the number of transformed cells, but its effect was less marked than that obtained when the polysaccharide was added before or at the time of infection.The finding that the inhibition of cell transformation by MuSV-124 was reversible after removal of the polysaccharide suggested that microalgal polysaccharides inhibited a late step after provirus integration into the host genome. In conclusion, our findings could support the possibility that the polysaccharide may affect early steps in the virus replication cycle, such as virus absorption into the host cells, in addition to its effect on a late step after provirus integration.

Novel spectral method for the study of viral carcinogenesis in vitro

Fourier transform infrared (FTIR) spectroscopy is a unique technique for the laboratory diagnosis of cellular variations based on the characteristic molecular vibrational spectra of the cells. Microscopic FTIR was used to investigate spectral differences between normal and malignant fibroblasts transformed by retrovirus infection. A detailed analysis showed significant differences between cancerous and normal cells. The contents of vital cellular metabolites were significantly lower in the transformed cells than in the normal cells. In an attempt to identify the cellular components responsible for the observed spectral differences between normal and cancerous cells, we found significant differences between DNA of normal and cancerous cells.

Studies of macromolecular prodrugs of zidovudine

The current problems in controlling severe viral infections such as AIDS as well as the lack of effective and safe therapeutic measures for such diseases have caused interest in systems such as macromolecular prodrugs potentially able to solve heavier drawbacks of conventional antiviral therapy. This review focuses on various approaches proposed in the literature in this field. Neoglycoproteins and synthetic protein-like structure polymers have been mainly proposed. In the first group, the possibility of incorporating into the polymeric structures a determined amount of sugar molecules make them interesting candidates for targeting of infected blood cells. The conjugate of zidovudine (AZT) and an anti-transferrin receptor antibody OX-26 has been proposed for brain targeting. The conjugate of AZT with alpha,beta-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) showed good release properties in a prolonged time.

Cutaneous T-cell lymphoma associated with HIV infection

BACKGROUND

Mycosis fungoides-type cutaneous T-cell lymphoma is uncommon in association with human immunodeficiency virus type 1 (HIV-1) infection. Reported patients have a high incidence of CD8+ T-cell lymphomas and erythroderma, are usually severely immunocompromised, and rapidly die. Chronic, more typical patch-plaque mycosis fungoides-type cutaneous T-cell lymphoma in association with HIV-1 infection has not been reported.

OBJECTIVE

We report two cases of stage 1B epidermotropic mycosis fungoides-type cutaneous T-cell lymphoma in HIV-1-infected men with no history of the acquired immunodeficiency syndrome.

METHODS

Clinical and laboratory data, including lesional immunophenotypic and immunogenotypic findings of two patients with HIV-1-associated cutaneous T-cell lymphoma, were studied.

RESULTS

Immunohistochemical analysis of skin determined the lesional infiltrate of one patient to be CD8+ (Leu-2+), CD7- (Leu-9-), and Leu-8- with germline lesional skin and blood T-cell receptor genes. The other was CD4- (Leu-3+), CD2- (Leu-5-), CD7- (Leu-9-), and Leu-8- with beta-chain T-cell receptor gene rearrangement in lesional skin and blood. Circulating Sézary cells were not detected in either patient. Peripheral CD4/CD8 T lymphocyte numbers did not appear to correlate with cutaneous disease activity or the predominant lesional T-cell subtype. Both patients were responsive to standard therapies and have experienced prolonged survival in excess of that generally reported for HIV-1-associated systemic peripheral and cutaneous T-cell lymphomas.

CONCLUSION

In the absence of severe immunodeficiency, HIV-1-infected patients with concomitant cutaneous T-cell lymphoma may follow a more typical slowly progressive course.

HIV and skin disease: the molecular biology of the human immunodeficiency virus

The human immunodeficiency virus (HIV) is a member of a family of retroviruses that cause chronic persistent infections in animals and in humans. The structure of this virus resembles that of other retroviruses but also contains important and complex regulatory elements. The expression of HIV can be influenced by the action of exogenous agents and cytokines. HIV has been isolated from a number of cell types, including cells in the skin, using sensitive detection methods such as the polymerase chain reaction and in situ hybridization. This article is a basic overview of the molecular biology of HIV and its presence in skin.

Peptide T improves psoriasis when infused into lesions in nanogram amounts

In each of 14 patients, two small but comparable psoriatic lesions were infused for 2 weeks with either saline or a saline solution of peptide T (as its analog D-ala1-peptide T amide) at 10(-7) mol/L with Alzet osmotic pumps worn extracorporeally. During infusion, lesions were photographed and scored for clinical features of psoriasis on a 9-point scale. After another 7 days, biopsy specimens were taken from the infused sites, and sections were scored for features of psoriasis on a 19-point scale. The differences between means for data from saline- and peptide T-infused lesions were evaluated statistically. Peptide T-infused lesions improved clinically; scores decreased from a mean of 4.35 initially to 1.57 at biopsy, whereas control lesions changed from 4.43 to 3.57 (p less than 0.01 for 1.57 vs 3.57). Histologic scores were also significantly different (5.28 for peptide T vs 10.00 for controls, 0.05 greater than p greater than 0.02). This study provides evidence that intralesionally infused peptide T demonstrates some clearing effect in psoriasis.