An experimental model for study of sialoglycoproteins of human immunodeficiency virus 1 epitope structures.

Sialic acid (SA) molecules located terminally on retrovirus glycoproteins (gps) play a key role in virus-cell interactions. The specificity of sialylation of Human immunodeficiency virus 1 (HIV-1) gps has not yet been studied. Looking for a convenient and reproducible experimental virus-cell model for studying the problem mentioned above we compared viral sialoglycoprotein (Sgp) patterns in H9/HTLV III B cells chronically infected with laboratory-adapted HIV-1LAI and MT-2 cells acutely infected with the same virus. Cytosols (CSs) and supernatant concentrates (SNs) from these cells and cell cultures, respectively, following N-acetyl-D-[U-14C]-mannosamine ([14C]NAcMan) labeling were subjected to preparative isoelectrofocusing and the obtained fractions were assayed for 14C-incorporation, reverse transcriptase (RT) activity and protein content. Sgp patterns in CSs from the two types of infection were similar. Highly sialylated peaks clustered mainly in the acidic region where the highest 14C-incorporation, RT activity and protein content were found. The 14C-incorporation was higher in CS than in SN. Analysis of CS from MT-2 cells infected with HIV-1 for the markers described above seems to be the experimental approach and model of choice for clinical isolates of HIV-1.

Some parameters of cell-mediated immunity in colon cancer patients.

16 colon cancer patients in the second clinical stage (according to the TNM classification), aged 34 to 71 years were studied before and 14 days after radical surgery. The in vitro cell-mediated immunity was evaluated using the rosette-forming test and blastogenic reactivity of blood lymphocytes to PHA. The percentage of total rosette-forming cells (T-cells) before and after surgery did not alter significantly (p less than 0.1). At the same time there was no significant difference between the number of rosette-forming cells in cancer patients compared to donors (p less than 0.1). Blastogenic reactivity of lymphocytes to PHA expressed as a stimulation index (S. I.) showed a significant decrease of that parameter in patients compared to donors (p less than 0.001). The S. I. was lower in patients 14 days after surgery than prior to treatment (p less than 0.01).

In vitro cell-mediated immune reactivity in colon cancer patients.

147 colon and/or rectum cancer patients in all clinical stages (according to TNM classification) aged 34 to 71 years were studied before radical surgery and 14, 45 and 90 days after it. The in vitro cell-mediated immunity was evaluated using the blastogenic transformation of blood lymphocytes to phytohemagglutinin (PHA), fast and total E rosettes. The immunosuppression observed in all clinical stages in comparison to donors becomes deeper 14 days after operation. 45 and 90 days after operation all three parameters studied increase but only in the clinical stage II (localized disease), the values reach and even surpass their initial level. Based on the obtained data conclusions were made in regard to the correlation of the lymphocyte functions to the clinical stage. In the localized (disseminated) stages a good (bad) ability of the immune system to recover is suggested.

Adsorption of ectyma contagiosum virus to cultured calf testis cells.

The adsorption of ectyma contagiosum virus (ECV) to calf testis cells was examined by attachment of 3H-thymidine-labelled ECV to calf testis cell monolayers and endpoint titration. The adsorption rate for ECV was calculated to be 5 X 10(-7) cm3 X min-1 X cell-1. ECV absorption was almost complete within 30 min though never exceeded more than 70% of the virus input.

Structure-Activity Relationships of Synthetic Coumarins as HIV-1 Inhibitors.

HIV/AIDS pandemics is a serious threat to health and development of mankind, and searching for effective anti-HIV agents remains actual. Considerable progress has been made in recent years in the field of drug development against HIV. A lot of structurally different coumarins were found to display potent anti-HIV activity. The current review demonstrates the variety of synthetic coumarins having unique mechanism of action referring to the different stages of HIV replication. Recent studies based on the account of various synthetic coumarins seem to indicate that some of them serve as potent non-nucleoside RT-inhibitors, another as inhibitors of HIV-integrase or HIV-protease. The merits of selecting potential anti-HIV agents to be used in rational combination drugs design and structure-activity relationships are discussed.The scientific community is looking actively for new drugs and combinations for treatment of HIV infection effective for first-line treatment, as well as against resistant mutants. The investigation on chemical anti-HIV agents gives hope and optimism about it. This review article describes recent progress in the discovery, structure modification, and structure-activity relationship studies of potent anti-HIV coumarin derivatives.

[Biochemical characteristics of a calf leukemia virus in chronically infected cells]. / Biokhimichna kharakteristika na levkozen virus ot teleta v khronichno zarazeni kletki.

Studied were the conditions of cultivation of FLK cells chronically infected with a calf leucosis virus. The gradient values of density were compared to those of the murine sarcoma virus--1.14--1.15 vs, 1.17--1.18/cm3. Established were the parameters of the reverse transcriptase reaction for the calf leukosis virus (Magnesium-dependent reverse transcriptase). Data showed that the calf leucosis virus may not resolutely be referred either to the B- or the the C-type of retroviruses.

[Kinetics of proliferation of a mouse tumor cell line originating in the fetal large intestine]. / Kinetika na proliferatsiia na kletuchna liniia ot mishi tumor, proizkhozhdasht ot fetalno debelo chervo

The authors examine the kinetics of cellular proliferation of the cellular line STS, originating from adenocarcinoma, obtained after "spontaneous" malignization of a fragment from fetal colon. The cells of STS grow as a single layer and reach exponential phase on the 48th hour, but stationary phase-on the 96th hour of the culture. Time for doubling the number of the cells TD at the exponential phase of growth is 12 hours. The mitotic index varies from 7% at the exponential phase to 1,3% at the stationary. Time of cellular cycle and its phases, estimated by the curves of the marked mitosis, shows the following values: TGi=5.3 hours, Ts=6 hours, TG2=0.5 hour, TM=1,2 hour, and TC=13 hours. The authors discuss the differences in the data of TC and TD.