Alterations in Retinal Tyrosine and Dopamine Levels in Rats Consuming Protein or Tyrosine-Supplemented Diets

The ad libitum ingestion of casein diets varying in protein content altered serum and retinal levels of tyrosine. The serum tyrosine level rose when protein ingestion was increased from 6 to 24% casein. In rats consuming high-protein diets (40% casein), no further increase in serum tyrosine level occurred, although the levels of other large neutral amino acids, which compete with tyrosine for retinal uptake, continued to rise. The activity of the liver enzyme tyrosine aminotransferase varied directly with the percentage of protein in the diet and may partially explain the failure of chronic high-protein feeding to increase serum tyrosine levels. The retinal tyrosine concentration was significantly correlated with the serum tyrosine level and with the serum tyrosine ratio at all levels of protein intake. Retinal 3,4-dihydroxyphenylalanine synthesis and dopamine (DA) level varied in parallel with the level of the precursor, tyrosine. Addition of pure L-tyrosine (1, 2, or 4%) to normal protein diets resulted in a stepwise increase in serum and retinal tyrosine levels and retinal DA turnover. Alterations of retinal tyrosine level as a result of change in amount of dietary protein or by its addition to the normal diet can influence retinal DA synthesis and release.     

Sex‐dependent alterations in BDNF‐TrkB signaling in the hippocampus of reelin heterozygous mice: a role for sex steroid hormones

Neurodevelopmental psychiatric disorders such as schizophrenia may be caused by a combination of gene × environment, gene × gene, and/or gene × sex interactions. Reduced expression of both Reelin and Brain‐Derived Neurotrophic factor (BDNF) has been associated with schizophrenia in human post‐mortem studies. However, it remains unclear how Reelin and BDNF interact (gene × gene) and whether this is sex‐specific (gene × sex). This study investigated BDNF‐TrkB signaling in the hippocampus of male and female Reelin heterozygous (Rln^+/?) mice. We found significantly increased levels of BDNF in the ventral hippocampus (VHP) of female, but not male Rln^+/? compared to wild‐type (WT) controls. While levels of TrkB were not significantly altered, phosphorylated TrkB (pTrkB) levels were significantly lower, again only in female Rln^+/? compared to WT. This translated to downstream effects with a significant decrease in phosphorylated ERK1 (pERK1). No changes in BDNF, TrkB, pTrkB or pERK1/2 were observed in the dorsal hippocampus of Rln^+/? mice. Ovariectomy (OVX) had no effect in WT controls, but caused a significant decrease in BDNF expression in the VHP of Rln^+/? mice to the levels of intact WT controls. The high expression of BDNF was restored in OVX Rln^+/? mice by 17β‐estradiol treatment, suggesting that Rln^+/? mice respond differently to an altered estradiol state than WT controls. In addition, while OVX had no significant effect on TrkB or ERK expression/phosphorylation, OVX + estradiol treatment markedly increased TrkB and ERK1 phosphorylation in Rln^+/? and, to a lesser extent in WT controls, compared to intact genotype‐matched controls. These data may provide a better understanding of the interaction of Reelin and BDNF in the hippocampus, which may be involved in schizophrenia.     

Phase II study of vaccinia melanoma cell lysates (VMCL) as adjuvant to surgical treatment of stage II melanoma

Summary Patients with stage II melanoma were vaccinated with vaccinia virus-induced melanoma cell lysates (VMCL). The vaccine contained viable vaccinia virus, membranous fragments and no intact nuclei. A number of antigens defined by monoclonal antibodies were detected in the vaccine including the ganglioside GD3 and DR antigens. Administration of the vaccine was associated with depression of natural killer cell activity against melanoma and K562 target cells in the first 3–6 months of treatment. Leucocyte dependent antibody (LDA) activity against melanoma cells was induced or increased in titre in approximately half of the patients studied. Continued vaccination was associated in a number of patients with a decrease in LDA titres. Studies on a small sample of patients revealed that this was associated with the development of serum factors which inhibited LDA activity. LDA activity appeared directed to non-MHC antigens on melanoma cells which were of at least two specificities. One specificity which was shared with antigens on a number of non-melanoma carcinoma cells was removed by absorption on fetal brain and may be similar to oncofetal antigens described by other workers. Reactivity against melanocytes was induced in some patients and may underlie the development of vitiligo in several patients. These results suggest that vaccines prepared from VMCL may be a favourable method for increasing immune responses against melanoma.     

Culture of intramural cardiac ganglia of the newborn guinea-pig

Summary The present study describes the ultrastructure of non-neuronal cells and their interrelationships with intracardiac neurones present in cultures dissociated atria and interatrial septum from newborn guinea-pig. When compared with the in situ preparation, most of these features in culture were similar to those observed in situ, but some differences were also apparent. Both mature and immature Schwann cells were observed in culture, and as in situ, the latter were closely associated with intracardiac neurones, whilst the former were more widely separated. The ultrastructure of satellite cells was more variable in culture than in situ: three general types were distinguished on the basis of their 10-nm filament content. This variation could be due to conditions of culture. Interstitial cells were present in culture and closely resembled those described in situ, although there was less space between cultured interstitial cells and their associated cells. Many fibroblasts, some myoblasts and a few mast cells were also found in the culture preparations.     

Calcitriol enhances gemcitabine antitumor activity in vitro and in vivo by promoting apoptosis in a human pancreatic carcinoma model system

Gemcitabine is the standard care chemotherapeutic agent to treat pancreatic cancer. Previously we demonstrated that calcitriol (1, 25-dihydroxycholecalciferol) has significant anti-proliferative effects in vitro and in vivo in multiple tumor models and enhances the activity of a variety of chemotherapeutic agents. We therefore investigated whether calcitriol could potentiate the cytotoxic activity of gemcitabine in the human pancreatic cancer Capan-1 model system. Isobologram analysis revealed that calcitriol and gemcitabine had synergistic antiproliferative effect over a wide range of drug concentrations. Calcitriol did not reduce the cytidine deaminase activity in Capan-1 tumors nor in the livers of Capan-1 tumor bearing mice. Calcitriol and gemcitabine combination promoted apoptosis in Capan-1 cells compared with either agent alone. The combination treatment also increased the activation of caspases-8, -9, -6 and -3 in Capan-1 cells. This result was confirmed by substrate-based caspase activity assay. Akt phosphorylation was reduced by calcitriol and gemcitabine combination treatment compared to single agent treatment. However, ERK1/2 phosphorylation was not modulated by either agent alone or by the combination. Tumor regrowth delay studies showed that calcitriol in combination with gemcitabine resulted in a significant reduction of Capan-1 tumor volume compared to single agent treatment. Our study suggests that calcitriol and gemcitabine in combination promotes caspase-dependent apoptosis, which may contribute to increased anti-tumor activity compared to either agent alone.Key words: calcitriol, gemcitabine, pancreatic carcinoma, apoptosis, Akt, ERK1/2     

Excess biglycan causes eyelid malformation by perturbing muscle development and TGF-alpha signaling

Tissue morphogenesis during development is regulated by growth factors and cytokines, and is characterized by constant remodeling of extracellular matrix (ECM) in response to signaling molecules, for example, growth factors, cytokines, and so forth. Proteoglycans that bind growth factors are potential regulators of tissue morphogenesis during embryonic development. In this study, we showed that transgenic mice overexpressing biglycan under the keratocan promoter exhibited exposure keratitis and premature eye opening from noninfectious eyelid ulceration due to perturbation of eyelid muscle formation and the failure of meibomian gland formation. In addition, in vitro analysis revealed that biglycan binds to TGF-alpha, thus interrupting EGFR signaling pathways essential for mesenchymal cell migration induced by eyelid epithelium. The defects of TGF-alpha signaling by excess biglycan were further augmented by the interruption of the autocrine or paracrine loop of the EGFR signaling pathway of HB-EGF expression elicited by TGF-alpha. These results are consistent with the notion that under physiological conditions, biglycan secreted by mesenchymal cells serves as a regulatory molecule for the formation of a TGF-alpha gradient serving as a morphogen of eyelid morphogenesis.     

Normal human pluripotent stem cell lines exhibit pervasive mosaic aneuploidy

Human pluripotent stem cell (hPSC) lines have been considered to be homogeneously euploid. Here we report that normal hPSC--including induced pluripotent--lines are karyotypic mosaics of euploid cells intermixed with many cells showing non-clonal aneuploidies as identified by chromosome counting, spectral karyotyping (SKY) and fluorescent in situ hybridization (FISH) of interphase/non-mitotic cells. This mosaic aneuploidy resembles that observed in progenitor cells of the developing brain and preimplantation embryos, suggesting that it is a normal, rather than pathological, feature of stem cell lines. The karyotypic heterogeneity generated by mosaic aneuploidy may contribute to the reported functional and phenotypic heterogeneity of hPSCs lines, as well as their therapeutic efficacy and safety following transplantation.