Isopods as indicators of the copper content of soil and litter

Summary In two species of isopods (mainlyTracheoniscus rathkei, plus a fewOniscus asellus) total copper content as well as the amount of copper extractable with zinc-dibenzyldithiocarbamate in CCl₄ (CTC) were determined. Both copper fractions show near perfect relationship with total copper concentration of the litter collected in the isopods' habitats. Between copperrich and copper-poor sites in Tirol, Austria, mean total copper content of the isopods varies by a factor of 7, mean CTC-extracted copper by a factor of 140 (Table 2). With the exception of one, particularly impoverished, site the concentration of copper in the CTC-extracted compartment reflects the total copper concentration of the food of the animals. Both copper fractions increase with the weight of animals, but the proportionality factor of the increase is three times larger for total copper than for CTC-extracted copper.A simplified geological map of Tirol is given in which the relationship between copper content of soil and litter and of the isopods at selected sites is indicated.     

Contact-dependent inhibition of growth of normal diploid human fibroblasts by plasma membrane glycoproteins

Homeostasis in vivo is maintained by a highly complex network of positive and negative signals. At the cellular level, this regulatory microenvironment can be divided, in a simplified fashion, into two major compartments: the humoral compartment, including compounds such as hormones, growth factors and nutrients, and the contact-environment compartment, including cell-cell and cell-matrix interactions. At least in cultures of diploid, non-transformed cells, cell-cell and cell-matrix interactions have been shown to be of major importance for the regulation of growth as well as of differentiation. Although until now the glycoprotein involved in the contact-dependent inhibition of growth has not been fully characterized, our studies give evidence for the involvement of a plasma membrane glycoprotein with an apparent molecular weight of approximately 80 kDa in the growth regulation of diploid human fibroblasts. The important characteristic of this glycoprotein is: the biologically active determinant resides in terminal, beta-glycosidically linked galactose residues on N-glycosidically linked glycans. From our studies, a receptor has to be postulated which, in addition to the galactose residues, has additional structural requirements for the specific binding of this glycoprotein, since other glycoproteins carrying terminal, beta-glycosidically linked galactose-residues are without biological activity. The postulated receptor is suggested to be defective in tumor cells, since these cells are no longer able to respond to cell-cell contacts with stopped proliferation, although they are able to inhibit growth of non-transformed cells. The inability of a tumor cell to recognize and to bind to the specific glycoprotein would result in a release from growth inhibition, leading to clonal growth of these cells. Further detailed studies on the structure and the regulation of the glycoprotein, as well as an attempt to isolate the postulated receptor, should lead to a better understanding of the complex pattern of growth regulation of normal cells.     

The role of stereotactic amygdalotomy in the treatment of temporal lobe epilepsy associated with behavioral disorders

The efficacy of bilateral stereotactic amygdalotomy for the treatment of aggressive behavioral disorders has been evaluated in a retrospective study of 67 cases. In addition 4 cases with complex partial seizures accompanied by aggressive outbursts revealing a unilateral epileptogenic focus in the amygdala or periamygdala region during preoperative stereoelectroencephalographic (SEEG) evaluation received a unilateral stereotactic amygdalotomy. Long-term follow-up of these 4 cases shows that 3 patients had considerable improvement in seizure frequency and severity as well as behavioral disturbances. The results in the remaining patients evaluated by surface EEG were inconclusive.