Mitogenic activity of snake venom lectins

Five lactose-inhibitable lectins have been isolated from snake venoms. These five share certain biochemical properties but are not identical (Gartner, Stocker & Williams, 1980; Gartner & Ogilvie, 1984). In this study the lectins were tested for their ability to stimulate lymphocytes to undergo DNA synthesis. We found that three of the lectins were comparable in mitogenic activity to the T cell lectin, concanavalin A (Con A). The mitogenic activity was blocked by lactose, a sugar which also blocks the haemagglutination activity of these lectins. Although mitogenic response appeared to be due to T cells, it depended on the presence of accessory cells in the culture. This requirement for macrophages could be replaced by the phorbol ester tumour promoter, 12-o-tetradecanoylphorbol-13-acetate (TPA).     

Cyclic AMP-binding proteins in normal and virus-transformed fibroblasts.

We examined the notion that altered growth regulation in virally transformed fibroblasts is due to a biochemical lesion affecting cytosol receptor for cyclic AMP. Normal cultured fibroblasts used after two passages and transformed cells from mouse and hamster possess equivalent amounts of total cyclic AMP receptors, with similar apparent affinities for cyclic AMP and similar distribution among isoenzymic forms of cyclic AMP-dependent protein kinase. Furthermore, untransformed 3T3 cells display only a single peak of cyclic AMP-binding activity, as resolved by ion-exchange chromatography. These findings do not support the view that defective binding of cyclic AMP is essential for loss of growth control in vitro.     

Fine needle aspiration of metastatic epithelioid angiosarcoma: a report of 2 cases

BACKGROUND: Epithelioid angiosarcomas (EAs) are uncommon mesenchymal tumors occurring in the thyroid, deep-seated soft tissues, parenchymal organs and, more rarely, superficial soft tissues of the head and neck. Due to their cytologic and immunocytochemical presentation on fine needle aspiration cytology (FNAC) samples, these neoplasms may closely mimic a number of different tumors, potentially causing an erroneous cytopathologic diagnosis unless immunophenotypical markers of vascular differentiation are sought in the cellular material. CASES: A 68-year-old man with a 1-year history of total thyroidectomy for EA presented with a suspicious right neck node and underwent FNA. A 63-year-old woman with a history of recurring multiple scalp nodules diagnosed as EA ultimately developed small multiple, bilateral lymph nodes in the neck and underwent FNA. In both cases a cytopathologic diagnosis of metastatic EA was made. CONCLUSION: The cytopathologic diagnosis of EA is a challenge. Knowledge of the clinical history is of great help in diagnosing metastatic lesions. The cytopathologicpicture of metastases is a useful way for cytopathologists to gain confidence with presentaton of this rare entity in primary sites on FNAC samples. Cytopathologic hints of vascular differentiation should be sought in the cytopathologic material when a diagnosis of EA is entertained.     

Breast cancer cells induce osteoblast apoptosis: a possible contributor to bone degradation

Breast cancer cells exhibit a predilection for metastasis to bone. There, the metastases usually bring about bone loss with accompanying pain and loss of function. One way that breast cancer cells disrupt the normal pattern of bone remodeling is by activating osteoclasts, the bone degrading cells. Nevertheless, targeting the osteoclasts does not cure the disease or result in bone repair. These observations indicate that osteoblast function also may be compromised. The objective of this study was to investigate the interaction of metastatic breast cancer cells with osteoblasts. Human metastatic breast cancer cells, MDA-MB-435 or MDA-MB-231, or their conditioned media were co-cultured with a human osteoblast line hFOB1.19. The breast cancer cells caused an increase in the prevalence of apoptotic osteoblasts. Apoptotic osteoblasts detected by the TUNEL assay or by caspase activity increased approximately two to fivefold. This increase was not seen with non-metastatic MDA-MB-468 cells. In an investigation of the mechanism, it was determined that the hFOB1.19 cells expressed fas and that fas was functional. Likewise the hFOB1.19 cells were susceptible to TNF-alpha, but this cytokine was not detected in the conditioned medium of the breast cancer cells. This study indicates that osteoblasts are the target of breast cancer cell-induced apoptosis, but fas/fas-ligand and TNF-alpha, two common initiators of cell death, are probably not involved in this aspect of the metastases/bone cell axis. There are several mechanisms that remain to be explored in order to determine how breast cancer cells bring about osteoblast apoptosis. Even though the specific initiator of apoptosis remains to be identified, the results of this study suggest that the mechanism is likely to be novel.     

Visual and chemical cues affecting the detection rate of the emerald ash borer in sticky traps

Using sticky traps, we compared the efficacy of chemical and visual lures, both alone and in combination, for improving the detection of populations of the emerald ash borer (EAB), Agrilus planipennis. Ash leaflets to which EAB visual decoys were pinned and coated with sticky material were able to trap EAB with as high a rate of detection as large sticky visually unbaited ‘prism traps’ currently used in wide‐scale EAB surveillance programs in North America, in a high‐density area. Both the sticky leaf traps and prism traps captured more EAB when a point source of plant odours, either manuka or phoebe oil, was deployed with the trap. For the sticky leaf traps, the shape of the EAB visual decoy lure was found to be important in optimizing the detection rate. Either an entire dead beetle or else two elytra placed side by side to mimic a resting beetle resulted in optimal trap performance. When two elytra were placed end to end or else other body parts were deployed, the traps lost their efficacy. Small green plastic surfaces to which EAB visual decoys were pinned were found to be fairly good substitutes for live ash leaflets, but the rate of beetle detection was reduced significantly from that of the ash leaflet plus EAB decoy. Throughout all experiments, a clear male bias occurred in sticky leaf traps when EAB visual decoys were placed on the traps. The implications of these findings for developing new trapping designs for EAB and other forest buprestids are discussed.     

Sirex noctilio in North America: the effect of stem‐injection timing on the attractiveness and suitability of trap trees

• 1 Sirex noctilio Fabricius, an invasive woodwasp responsible for severe economic damage to pine industries in the southern hemisphere, is now established in the northeastern U.S.A. and portions of eastern Canada.
• 2 Parts of North America are considered to be high risk for S. noctilio invasion. Effective detection tools, including trap trees, are needed to monitor and survey S. noctilio populations.
• 3 The present study was conducted to determine the optimal time to chemically stress a tree when aiming to attract the most S. noctilio to the host substrate, as well as to determine which timing produced the most adult progeny. Both of these measures (host attraction and host suitability for development) support the main objectives of the study by offering improved methods for monitoring and management of S. noctilio.
• 4 Red pine (Pinus resinosa) and Scots pine (Pinus sylvestris) were treated with Dicamba at three time intervals. Multiple funnel lindgren traps were placed on these trees and, at the end of the flight season, the treatment trees were felled and brought into the laboratory. The number of S. noctilio caught in the traps (host attraction) and the number of S. noctilio emerged from the treated trees (host suitability) were determined.
• 5 Optimal timing of the chemical girdle was dependent on host species. Significantly more female S. noctilio were captured on trap trees prepared 1 month before flight (red pine and Scots pine) or prepared at flight (Scots pine) compared with other treatments. There were also significantly more females reared from Scots pine trap trees prepared at flight and red pine trap trees prepared 1 month before and/or at flight.
• 6 By the beginning of August, most (79%) of the S. noctilio for the flight season were caught in the traps at the trap trees. The sex ratio (males : females) was closer to 1 : 1 than previously reported in studies from other countries.
• 7 The results obtained in the present study demonstrate that timing is important when creating a trap tree with herbicide in North America, whether for the purpose of detection or as part of a biological control effort.

     

Mitogenic Activity of Snake Venom Lectins

Abstract. Five lactose-inhibitable lectins have been isolated from snake venoms. These five share certain biochemical properties but are not identical (Gartner, Stocker & Williams, 1980; Gartner & Ogilvie, 1984). In this study the lectins were tested for their ability to stimulate lymphocytes to undergo DNA synthesis. We found that three of the lectins were comparable in mitogenic activity to the T cell lectin, concanavalin A (Con A). the mitogenic activity was blocked by lactose, a sugar which also blocks the haemagglutination activity of these lectins. Although mitogenic response appeared to be due to T cells, it depended on the presence of accessory cells in the culture. This requirement for macrophages could be replaced by the phorbol ester tumour promoter, 12- o -tetradecanoylphorbol-13-acetate (TPA).     

Prolactin receptor gene expression in rat splenocytes and thymocytes during oestrous cycle, pregnancy and lactation

Much evidence suggests that prolactin (PRL) has an immunoregulatory function. Part of this evidence is that the receptors for PRL are present on lymphocytes. Probably the effects of PRL on cells of the immune system depend on the level and specific forms of PRL-R present on the target cells. Therefore, PRL-R expression at both protein and mRNA levels was examined during oestrous cycle, pregnancy and lactation using Western blotting and PCR analysis. Antibody to the long form of PRL-R detected 84 and 42 kDa protein bands in the spleen but only 84 kDa band in the thymus. The expression pattern of these two protein bands was different in the spleen, suggesting that these two isoforms of PRL-R long form are differentially regulated by the hormones of oestrous cycle. In addition, depending on the tissue, the level of mRNA for the short and long forms of PRL-R showed a significant change at different stages of oestrous cycle. Moreover, 42 and 84 kDa PRL-R bands were detected in both spleen and thymus throughout the pregnancy and lactation; however, the expression pattern of 84 kDa protein band was different between tissues. This finding suggests that each tissue exhibits differential response to hormones which affect PRL-R content.