third larval instar stage, suggesting that larval musculature is intact and that parkin is required only in pupal and adult muscle. parkin flies do not show an age-dependent dopaminergic neuron loss in the brain, even after aging adults for 3 weeks. Nevertheless, degeneration of IFMs demonstrates the importance of parkin in maintaining specific cell groups, perhaps those with a high-energy demand and the concomitant production of high levels of free radicals. parkin mutants will be a valuable model for future analysis of the mechanisms of cell and tissue degeneration.
Multilayer nanofilms, formed by the layer-by-layer (LbL) adsorption of positively and negatively charged polyelectrolytes, are promising substrates for tissue engineering. We investigate here the attachmemt and function of hepatic cells on multilayer films in terms of film composition, terminal layer, rigidity, charge, and presence of biofunctional species. Human hepatocellular carcinoma cells (HepG2), adult rat hepatocytes (ARH), and human fetal hepatoblasts (HFHb) are studied on films composed of the polysaccharides chitosan (CHI) and alginate (ALG), the polypeptides poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA), and the synthetic polymers poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS). The influence of chemical cross-linking following LbL assembly is also investigated. We find HepG2 to reach confluence after seven days of culture on only 2 of 18 candidate multilayer systems: (PAH-PSS)n (i.e. n PAH-PSS bilayers) and cross-linked (PLL-ALG)n-PLL. These two systems, as well as cross-linked (PLL-PGA)n-PLL, support attachment and function (in terms of albumin production) of ARH, provided collagen is adsorbed to the top of the film. (PAH-PSS)n, cross-linked (PLL-ALG)n, and cross-linked (PLL-PGA)n-PLL films all support attachment, layer confluence, and function of HFHb, with the latter film promoting the greatest level of function at 8 days. Overall, film composition, terminal layer, and rigidity are key variables in promoting attachment and function of hepatic cells, while film charge and biofunctionality are somewhat less important. These studies reveal optimal candidate multilayer biomaterials for human liver tissue engineering applications.
Background Disulfiram has been an effective cocaine addiction pharmacotherapy, and one of its possible mechanisms of efficacy is through copper chelation and inhibition of an enzyme involved in catecholamine metabolism, dopamine β-hydroxylase (DβH), which converts dopamine to norepinephrine. A variant in the gene encoding DβH leads to reduced DβH activity and as such, disulfiram may not be an effective treatment of cocaine dependence for individuals with this variant. This study explored that potential matching. Methods Seventy-four cocaine and opioid co-dependent (DSM-V) subjects were stabilized on methadone for two weeks and subsequently randomized into disulfiram (250 mg/day, N =34) and placebo groups (N =40) for 10 weeks. We genotyped the DBH gene polymorphism, −1021C/T (rs1611115), that reduces DβH enzyme levels and evaluated its role for increasing cocaine free urines with disulfiram. Results Using repeated measures analysis of variance, corrected for population structure, disulfiram pharmacotherapy reduced cocaine positive urines from 80% to 62% (p = .0001), and this disulfiram efficacy differed by DBH genotype group. Patients with the normal DβH level genotype dropped from 84% to 56% on disulfiram (p = .0001), while those with the low DBH level genotype showed no disulfiram effect. Conclusions This study indicates that a patient’s DBH genotype could be used to identify a subset of individuals for which disulfiram treatment may be an effective pharmacotherapy for cocaine dependence.
Immunodeficient mice bearing components of a human immune system present a novel approach for studying human immune responses. We investigated the number, phenotype, developmental kinetics and function of developing human immune cells following transfer of CD34+ hematopoietic stem cell (HSC) preparations, originating from second trimester human fetal liver (HFL), umbilical cord blood (UCB), or granulocyte colony-stimulating factor-mobilized adult blood (G-CSF-AB) delivered via intrahepatic injection into sublethally irradiated neonatal NOD-scid/γc −/− , Balb/cRag1 −/− γc −/− , and C.B-17-scid/bg mice. HFL and UCB HSC provided the greatest number and breadth of developing cells. NOD-scid/γc −/− and Balb/c-Rag1 −/− γc −/− harbored human B and dendritic cells as well as human platelets in peripheral blood, whereas NOD-scid/γc −/− mice harbored higher levels of human T cells. NOD-scid/γc −/− mice engrafted with HFL CD34+ HSC demonstrated human immunological competence evidenced by white pulp expansion and increases in total human immunoglobulin following immunization with T-dependent antigens, and delayed type hypersensitivity-infiltrating leukocytes in response to antigenic challenge. In conclusion, we describe an encouraging base system for studying human hematopoietic lineage development and function utilizing human HFL or UCB HSC-engrafted NOD-scid/γc −/− mice that is well suited for future studies toward the development of a fully competent humanized mouse model.
Patterning of sensory organs requires precise regulation of neural induction and repression. The neurocrystalline pattern of the adult Drosophila compound eye is generated by ordered selection of single founder photoreceptors (R8s) for each unit eye or ommatidium. R8 selection requires mechanisms that restrict R8 potential to a single cell from within a group of cells expressing the proneural gene atonal (ato). One model of R8 selection suggests that R8 precursors are selected from a three-cell ‘R8 equivalence group’ through repression of ato by the homeodomain transcription factor Rough (Ro). A second model proposes that lateral inhibition is sufficient to select a single R8 from an equipotent group of cells called the intermediate group (IG). Here, we provide new evidence that lateral inhibition, but not ro, is required for the initial selection of a single R8 precursor. We show that in ro mutants, ectopic R8s develop from R2,5 photoreceptor precursors independently of ectopic Ato and hours after normal R8s are specified. We also show that Ro directly represses the R8 specific zinc-finger transcription factor senseless (sens) in the developing R2,5 precursors to block ectopic R8 differentiation. Our results support a new model for R8 selection in which lateral inhibition establishes a transient pattern of selected R8s that is permanently reinforced by a repressive bistable loop between sens and ro. This model provides new insight into the strategies that allow successful integration of a repressive patterning signal, such as lateral inhibition, with continued developmental plasticity during retinal differentiation.
This paper reviews current scientific information about the duration of immunity induced in dogs by infection or vaccination. It describes the shortcomings of the methods used to measure the immune responses of dogs, and explains the need for basic studies on the nature of protective humoral and cellular responses, and standardised assays for the long-term duration of immunity to pathogens other than rabies. The information is inadequate to warrant uniform recommendations on the ideal intervals for vaccination; each vaccine must be evaluated on the basis of its own merits and the characteristics of the disease it is intended to guard against.
Foxp3 is a key transcription factor for differentiation and function of regulatory T (Treg) cells that is critical for maintaining immunological self-tolerance. Therefore, increasing Treg function by Foxp3 transduction to regulate an inflammatory immune response is an important goal for the treatment of autoimmune and allergic diseases. Here we have generated a cell-permeable Foxp3 protein by fusion with the unique human HHph-1-PTD (protein transduction domain), examined its regulatory function in T cells, and characterized its therapeutic effect in autoimmune and allergic disease models. HHph-1-Foxp3 was rapidly and effectively transduced into cells within 30 min and conferred suppressor function to CD4 + CD25 − T cells as well as directly inhibiting T-cell activation and proliferation. Systemic delivery of HHph-1 Foxp3 remarkably inhibited the autoimmune symptoms of scurfy mice and the development of colitis induced by scurfy or wild-type CD4 T cells. Moreover, intranasal delivery of HHph-1-Foxp3 strongly suppressed ovalbumin-induced allergic airway inflammation. These results demonstrate the clinical potential of the cell-permeable recombinant HHph-1-Foxp3 protein in autoimmune and hypersensitive allergic diseases.
Background Nearly half of all infiltrating leukocytes in rejecting human allografts are macrophages, yet, in comparison with T cells, much less is known about the contribution of this cell type to rejection. Our laboratory has previously described models of rejection of human skin or artery grafts in immunodeficient mouse hosts mediated by adoptively transferred allogeneic T cells. However, mature human monocyte/macrophages have consistently failed to engraft in these animals. Here, we describe the introduction of human CD68+ macrophages into irradiated immunodeficient mice by transplantation of enriched CD34+ hematopoietic stem-cells isolated from peripheral blood of G-colony-stimulating factor pretreated adults. Methods We investigated strains of immunodeficient mice bearing human tissue grafts (skin and artery) inoculated with 1×106 human CD34+ adult hematopoietic stem cells, peripheral blood monuclear cells autologous to the CD34 donor, or both for human cell engraftment. Results In the absence of T cells, CD68+ CD14+ macrophages infiltrate allogeneic human skin but produce little injury or thrombosis. Both responses are enhanced when combined with adoptive transfer of T cells autologous to the hematopoietic stem cells as exemplified by the induction of the macrophage activation marker CD163. CD68+ macrophages also infiltrate allogeneic arterial interposition grafts, producing intimal expansion and calcification in the absence of T cells. Conclusions These new models may be used to study the role of human macrophages in transplant rejection and other pathologies in vivo.
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