Simultaneous Isolation of Three Different Stem Cell Populations from Murine Skin

The skin is a rich source of readily accessible stem cells. The level of plasticity afforded by these cells is becoming increasingly important as the potential of stem cells in Cell Therapy and Regenerative Medicine continues to be explored. Several protocols described single type stem cell isolation from skin; however, none of them afforded simultaneous isolation of more than one population. Herein, we describe the simultaneous isolation and characterization of three stem cell populations from the dermis and epidermis of murine skin, namely Epidermal Stem Cells (EpiSCs), Skin-derived Precursors (SKPs) and Mesenchymal Stem Cells (MSCs). The simultaneous isolation was possible through a simple protocol based on culture selection techniques. These cell populations are shown to be capable of generating chondrocytes, adipocytes, osteocytes, terminally differentiated keratinocytes, neurons and glia, rendering this protocol suitable for the isolation of cells for tissue replenishment and cell based therapies. The advantages of this procedure are far-reaching since the skin is not only the largest organ in the body, but also provides an easily accessible source of stem cells for autologous graft.     

Immunoregulatory T-cell defects in B-cell chronic lymphocytic leukemia: cause or consequence of the disease? The contributory role of decreased availability of interleukin 2 (IL-2)

Several phenotypic and functional defects have been described within the residual T-lymphocyte population of patients with B-cell chronic lymphocytic leukemia (B-CLL), particularly in those in the more advanced stages of the disease. In this study, we review these abnormalities and discuss their possible effects on the course of the illness. Particular emphasis is devoted to the role of interleukin 2 (IL-2) in B-CLL. Evidence is provided that the IL-2 released by B-CLL T-lymphocytes may be utilized by the neoplastic B-cell clone that expresses the IL-2 receptor and that decreased availability of IL-2 may play a contributory role in some of the T-cell defects encountered in B-CLL.     

Tumour inhibition by interleukin-2 at the tumour/host interface

Until recently, lymphokines were regarded suspiciously as 'ill-defined factors'. Today, however, some of them have been clearly defined in both structural and functional terms. The interleukin-2 (IL-2) molecule and its specific membrane receptors have been the subject of particular attention. Endogenous IL-2 has proved to be an important signal for the activation and expansion of various cell-mediated immunity functions, while exogenous IL-2 has been used to activate numerous cell functions, both in vitro and in vivo, as well as in tumour immunotherapy, both alone or combined with lymphocytes previously activated in vitro (lymphokine-activated killer cells). Adoptive transfer of these cells together with high doses of IL-2 is particularly promising from the clinical standpoint, though by no means free from problems. IL-2 can also be employed in small doses locally in the presence of non-activated lymphocytes from tumour bearing mice to induce a local reaction that subsequently becomes systemic and can lead to the rejection of incipient tumours. Various host immune cells, primarily eosinophils and lymphocytes are involved in this reaction, which can also give rise to tumour-specific immune memory. In this way, the host immune system, despite its inevitable defeat in the first battle against a tumour, may acquire an important role in the long war that lies ahead.     

Heterologous sera: a target for in vitro cell-mediated cytotoxicity.

During the course of studies in inbred Strain 2 Guinea pigs on in vitro cell-mediated cytotoxicity to viral induced fibrosarcomas, it was observed that fetal calf serum in the medium in which the target cells were grown was responsible in some instances for much of the cytotoxicity observed. This fetal calf serum-specific cytotoxicity seemed mainly mediated by T cells and appeared to be independent on histocompatibility between target and killer cells.     

Effect of helium-oxygen pressure on dopamine detected in vivo in the striatum of hamsters

Free-moving hamsters chronically implanted in the striatum with carbon multifiber electrodes selective to dopamine were compressed in a helium-oxygen breathing mixture to 81 bars. Under these conditions, there was an increase in the electrochemical responses recorded from the carbon electrode by differential pulse voltammetry, which occurred during the compression and disappeared when the animals returned to the surface. This change was related to an increase in extracellular dopamine levels induced by the increase in pressure of the helium-oxygen mixture.     

Effects of sodium dodecyl sulphate on the aquatic macrophytes Azolla and Lemna

Abstract

In this work, we determined the tolerance to sodium dodecyl sulphate (SDS) of Azolla filiculoides and of Lemna minor. The presence of the detergent in the media affected growth more than the chlorophyll content. On the basis of the effect indices, Lemna is more tolerant to SDS than Azolla. The fern had a better capacity, compared with duckweed, to remove and accumulate the pollutant.     

Chromosomal diversity in two synchronopatric species of Hoffmannseggella (Orchidaceae)

Hoffmannseggella viridiflora Verola & Semir (Laeliinae, Orchidaceae) is a recently discovered species in the campos rupestres vegetation of the Espinhaço Range, MG, Brazil, in synchronopatry with H. bradei (Pabst) V. P. Castro & Chiron. Both morphological and phenological studies indicate that these species are closely related. To substantiate the differentiation of these two species we examined their chromosome numbers and morphologies. The two species had different chromosome numbers, with H. bradei having 2n = 40 and H. viridiflora having 2n = 44 chromosomes, an aneuploid number not previously documented in the genus. Meiotic behavioral studies undertaken with H. bradei revealed many abnormalities related to bivalent numbers and chromosome migration, suggesting that meiotic abnormalities could generate aneuploid gametes and perhaps aneuploid zygotes. Karyotype formulas and chromosome morphologies are quite different between the species, so H. viridiflora was not directly derived from H. bradei through simple chromosome additions. Complementary analyses are necessary to understand the process and species involved in the origin of H. viridiflora.     

Serotonin depletion produces long lasting increase in striatal glutamatergic transmission

The ability of serotonin (5-HT) to influence striatal glutamatergic transmission was examined by determining changes over time in glutamate extracellular levels, transporter expression and synaptosomal uptake in rats with lesion of serotonergic neurones. By 8 days after intraraphe injections of 5,7-dihydroxytryptamine, producing 80% decreases in striatal tissue 5-HT levels, no changes were observed in the glutamatergic transmission. When 5-HT depletion was almost complete (21 days post-lesion), high affinity glutamate uptake in striatal synaptosomal preparations was significantly increased (156% of control), although no changes in striatal GLT1, GLAST and EAAC1 mRNAs, and GLT1 protein were detected by in situ hybridization and immunohistochemistry. Meanwhile, the serotonin lesion produced large increases in basal extracellular levels of glutamate and glutamine (364% and 259%, respectively) determined in awake rats by in vivo microdialysis, whereas no change was observed in dopamine levels as compared with control rats. High potassium depolarization as well as L-trans-pyrrolidine-2,4-dicarboxylate, also induced larger increases in extracellular levels of glutamate in lesioned rats than in controls. Finally, similar changes in glutamate transmission were observed by 3 months post-lesion. These results suggest that 5-HT has a long lasting and tonic inhibitory influence on the striatal glutamatergic input, without affecting the basal dopaminergic transmission.     

A phenotypic and functional analysis of long-lived B and T lymphocytes

The lymphocyte composition of spleen, lymph nodes, bone marrow, and thymus of mice submitted to hydroxyurea treatments for four consecutive days was studied. The treatment selects for small lymphocyte populations that represent between 4 and 20% of control numbers in the various organs. Spleen and bone marrow contain the same B cell population with a low IgM, high IgD, low I-E phenotype, which respond to LPS at control clonal frequencies. The T cell compartment is equally depleted, and the lymphocytes remaining contain frequencies of clonable cells in response to mitogens and IL-2 that are comparable to those detected in normal spleen cells. Overall, the results suggest that only a minor fraction of all lymphocytes in a normal young adult mouse have life spans longer than 4 days.