Pseudoaromatase in circulating lymphocytes

A variety of data suggesting a relationship between estrogens and the immune system prompted a study of aromatase activity in blood lymphocytes. A tritiated water aromatase assay detected activity of 1.9 to 25.1 pmol/g protein/h in 14 samples of human lymphocytes. To confirm these results, additional tritiated water and product isolation assays were performed on a large pool of lymphocytes obtained from 4 U of blood. An assay using [1β-³H]androstenedione generated high apparent aromatase activity, 943 pmol/g protein/h, but this activity could not be blocked by the aromatase inhibitor, CGS 16949A. More direct methods of evaluation yielded the following results: (1) PCR demonstrated no aromatase mRNA production in lymphocytes; (2) direct product isolation using [1,2,6,7-³H]androstenedione yielded insignificant production of estrone and estradiol; (3) immunostaining of fixed lymphocyte smears with a polyclonal antibody to aromatase yielded equivocal results. These data suggest the presence of pseudoaromatase in blood lymphocytes. Since circulating lymphocyte pseudoaromatase levels can be correlated with various factors in patients, such as age, menopausal status, and glucose ingestion, further studies of this activity are warranted.     

Effect of the tumor promoter TPA on the distribution of PHA-stimulated human lymphocytes by cell cycle phases

Patterns of the cell cycle distribution in human peripheral blood lymphocytes, stimulated by PHA alone and PHA plus 12-o-tetradecanoylphorbol-13-acetate (TPA), were studied using DNA cytometry in different times after PHA stimulation. In the first period (nearly 3 days after PHA stimulation) TPA induces no significant differences in the characters under consideration, but in the later period, when the proliferation of the cultures stimulated by PHA alone is reducing, in other cultures stimulated by PHA plus TPA the percentage of cells in S-phase does not reduce, whereas the percentage of cells in G2-phase is rising, which may suggest that this phase is blocked. Concurrently the tetraploid cells are appearing. Accumulation of cells in G2-phase can be overcome by the application of chlorpromazine, which is known to inhibit the membrane-associated protein kinase C.     

The promise of circulating tumor cell analysis in cancer management

Enumeration and molecular characterization of circulating tumor cells isolated from peripheral blood of patients with cancer can aid selection of targeted therapy for patients, monitoring of response to therapies and optimization of drug development, while also providing valuable information about intratumoral heterogeneity.     

Effects of flowing RBCs on adhesion of a circulating tumor cell in microvessels

Adhesion of circulating tumor cells (CTCs) to the microvessel wall largely depends on the blood hydrodynamic conditions, one of which is the blood viscosity. Since blood is a non-Newtonian fluid, whose viscosity increases with hematocrit, in the microvessels at low shear rate. In this study, the effects of hematocrit, vessel size, flow rate and red blood cell (RBC) aggregation on adhesion of a CTC in the microvessels were numerically investigated using dissipative particle dynamics. The membrane of cells was represented by a spring-based network connected by elastic springs to characterize its deformation. RBC aggregation was modeled by a Morse potential function based on depletion-mediated assumption, and the adhesion of the CTC to the vessel wall was achieved by the interactions between receptors and ligands at the CTC and those at the endothelial cells forming the vessel wall. The results demonstrated that in the microvessel of \(15\,\upmu \hbox {m}\) diameter, the CTC has an increasing probability of adhesion with the hematocrit due to a growing wall-directed force, resulting in a larger number of receptor–ligand bonds formed on the cell surface. However, with the increase in microvessel size, an enhanced lift force at higher hematocrit detaches the initial adherent CTC quickly. If the microvessel is comparable to the CTC in diameter, CTC adhesion is independent of Hct. In addition, the velocity of CTC is larger than the average blood flow velocity in smaller microvessels and the relative velocity of CTC decreases with the increase in microvessel size. An increased blood flow resistance in the presence of CTC was also found. Moreover, it was found that the large deformation induced by high flow rate and the presence of aggregation promote the adhesion of CTC.     

Numerical study on the adhesion of a circulating tumor cell in a curved microvessel

Biomechanics and Modeling in Mechanobiology - The adhesion of a circulating tumor cell (CTC) in a three-dimensional curved microvessel was numerically investigated. Simulations were first performed...     

Effect of chemotherapy on human tumor heterografts and lymphocytes in athymic mice

Sensitivity of human serially transplanted tumours (melanoma, hepatoma, lung, stomach and bladder cancer) to monochemotherapy was studied in nude mice. The following groups of nude mice were examined: intact and those with human xenografts (control and mice treated with alkylating agents). Changes in peripheral blood morphology have been revealed and functional activity of the energetic enzymes (SDH and alpha-GPDH) has been cytochemically discovered.     

Stimulation of endothelial cell binding of lymphocytes by tumor necrosis factor

Lymphokines and monokines have been reported to affect endothelial cell (EC) morphology and function. In experiments here described, we have demonstrated that recombinant tumor necrosis factor (TNF) stimulates the adhesion of T lymphocytes to confluent monolayers of human umbilical vein EC. The increase in adhesion induced by TNF was EC-specific inasmuch as preincubation of the lymphocytes with TNF did not alter binding, and preincubation of human dermal fibroblasts with TNF did not increase their inherently low adhesiveness for lymphocytes. Stimulation of T-EC binding occurred after treatment of the EC with as little as 0.01 U/ml (1 pg/ml) of TNF. In kinetic experiments, preincubation of EC with TNF for 4 hr resulted in optimal adhesion. TNF-treated EC retained their increased adhesiveness after fixation with paraformaldehyde, suggesting that TNF stimulated binding by increasing the expression or accessibility of EC surface receptors for lymphocytes. Although antibodies to the lymphocyte function-associated antigen 1 alpha- or beta-chains on the T cell markedly inhibited unstimulated T-EC binding, such antibodies had no effect on the increase in EC adhesiveness induced by TNF, indicating that the increased binding resulted from the generation of an alternate binding receptor on the EC membrane. These findings provide additional evidence that cytokines participate in the mobilization of mononuclear cells in the chronic inflammatory reaction by stimulation of the adhesiveness of endothelium for circulating lymphocytes.     

Effect of low inoculation density in the scale-up of insect cell cultures

The scale-up of insect cell cultures and the production of baculovirus with these cultures is dependent on the inoculation density applied. The effect of applying a low inoculation on the specific growth rate and on the duration of the lag phase was tested. Three different cell lines, HzAm1, Ha2302, and Sf21 were tested in a total of five cell line/medium combinations. Growth in suspension culture was examined, and data obtained were fitted with the Gompertz equation. A significant decline in specific growth rate with decreasing inoculation density was observed in all cell line/medium combinations, except for HzAm1. No critical inoculation density, below which no growth would occur, was found. In suspension culture in shake flasks, an inoculation density of 5 x 10(4) cells/mL is achievable, without severely influencing the overall growth rate. A lower inoculation density in suspension culture results in less steps in the scale-up process and might be a tool in bypassing the viral passage effect.     

Effect of inoculation density on potato micropropagation

The in vitro microplant growth of two potato genotypes viz., Kufri Jyoti and Kufri Chandramukhi was affected by inoculation density. After 2 weeks of culture, maximum microshoot length and number of roots/microplant were observed at an inoculation density of five single node cuttings per culture tube. There was difference in response between the genotypes for mean number of nodes/microplant. The number of explants cultured per tube did not significantly change microplant growth produced over 4 weeks of culture.     

Genetic influence on the levels of circulating CD5 B lymphocytes

By using sensitive two- and three-color immunofluorescence analyses, we readily detect CD5B cells (Leu 1 B cells) in the peripheral blood of normal adults. These circulating CD5 B lymphocytes coexpress B cell differentiation antigens CD20, CD21, CD19, sIgM and sIgD, and HLA-DR. Unlike CD5-negative B cells from most adults, however, these cells co-express CD11, a finding also noted for malignant CD5 B cells from several patients with CLL. Between normal volunteers, there exists heterogeneity in the proportion of PBL that co-express CD5 and B cell surface antigens, such cells representing between 0 and 6% of peripheral lymphocytes. Despite such heterogeneity between unrelated individuals, analyses of repeated blood samples from the same person reveal that the proportions of CD5 B lymphocytes are constant over time. Examination of blood samples from related family members, monozygotic twins, and triplets indicate that the relative proportion of circulating CD5 B cells may be genetically regulated. This is apparent even for monozygotic twins discordant for rheumatoid arthritis. Four sets of such twins are examined, each set having one individual with clinically active, seropositive rheumatoid arthritis and another without detectable rheumatoid factor or clinical pathology. Despite such noted differences, twins from each set share identical proportions of circulating CD5 B cells. In summary, our studies indicate that the level of CD5 B lymphocytes is a rather stable phenotypic trait that is under genetic control.     

Syrian hamster sensitivity to tumor cell inoculation in the period of pregnancy and nursing the cubs

The influence of pregnancy and lactation on the sensitivity of females to the transplantation of tumor cells was studied in experiments with Syrian hamsters. During the first days of the joint keeping of males and females (1--6 days before pregnancy) the latter ones were shown to be more resistant to the transplantation of tumor cells as compared with unbearing females. However, days 1--8 of pregnancy and during lactation no subtantial differences were revealed between animal groups compared in the sensitivity to the transplantation of tumor cells.     

淋巴细胞合成的内源性儿茶酚胺对T细胞增殖功能的影响

目的：提供淋巴细胞合成儿茶酚胺（CAs）的证据,并探讨淋巴细胞合成的内源性CAs对淋巴细胞自身功能的影响及其受体介导机制。方法：用RT-PCR技术检测CAs合成的限速酶酪氨酸羟化酶（TH）mRNA在大鼠肠系膜淋巴结细胞内的表达。用单胺氧化酶（CAs降解酶）的抑制剂优降宁及α1、α2、β1和β2肾上腺素受体（AR）的拮抗剂作用于淋巴细胞．然后用四唑蓝比色法测定淋巴细胞对刀豆蛋白A（ConA）刺激的增殖反应。结果：大鼠肠系膜淋巴结细胞具有,TH mRNA的表达,并且淋巴细胞在用ConA刺激活化后,其TH mRNA的表达明显上调。10^-6和10^-5mol／L优降宁能显著抑制ConA诱导的T淋巴细胞增殖,而10^-7mol／L优降宁不能明显降低T淋巴细胞的增殖反应。β2-AR拮抗剂ICI 118551（10^-7和10^-6mol／L）可完全阻断优降宁（10^-5mol／L）对T细胞增殖的抑制作用;α1-AR拮抗剂柯喃因和α2-AR拮抗剂育亨宾部分阻断优降宁抑制T细胞增殖的作用;而β1-AR拮抗剂阿替洛尔不能阻断优降宁的抑制作用。结论：淋巴细胞具有合成CAs的能力,这种合成能力随着淋巴细胞的激活而明显增强。淋巴细胞合成的内源性CAs可能通过自分泌或／和旁分泌路径主要激活淋巴细胞上的β2-AR,从而抑制T细胞的增殖反应。     

Human CD5 protects circulating tumor antigen-specific CTL from tumor-mediated activation-induced cell death

We previously characterized several tumor-specific T cell clones from PBL and tumor-infiltrating lymphocytes of a lung cancer patient with identical TCR rearrangements and similar lytic potential, but with different antitumor response. A role of the TCR inhibitory molecule CD5 to impair reactivity of peripheral T cells against the tumor was found to be involved in this process. In this report, we demonstrate that CD5 also controls the susceptibility of specific T cells to activation-induced cell death (AICD) triggered by the tumor. Using a panel of tumor-infiltrating lymphocytes and PBL-derived clones expressing different levels of CD5, our results indicate that T lymphocyte AICD in response to the cognate tumor is inversely proportional to the surface expression level of CD5. They also suggest a direct involvement of CD5 in this process, as revealed by an increase in tumor-mediated T lymphocyte AICD following neutralization of the molecule with specific mAb. Mechanistically, our data indicate that down-regulation of FasL expression and subsequent inhibition of caspase-8 activation are involved in CD5-induced T cell survival. These results provide evidence for a role of CD5 in the fate of peripheral tumor-specific T cells and further suggest its contribution to regulate the extension of CTL response against tumor.