Metabolic abnormalities in children of non-insulin dependent diabetics.

Non-insulin dependent diabetes appears to be an inherited condition. A study of young offspring of non-insulin dependent diabetics was conducted to determine whether metabolic abnormalities could be found at a young age before clinical diabetes developed. Thirteen patients with non-insulin dependent diabetes were selected who fulfilled the following criteria: they had a sibling who also had non-insulin dependent diabetes, their spouse was non-diabetic, and the offspring were aged between 12 and 45 years, not diabetic, and available for study. All 32 offspring had a 75 g oral glucose tolerance test, and results in 13 of them, one randomly selected from each family, were compared with 13 controls of similar age, sex, and weight. The offspring had significantly higher fasting concentrations of glucose, higher proportions of haemoglobin A1, and higher concentrations of insulin, C peptide, and glucagon. After glucose challenge the increases in both glucose and C peptide concentrations were significantly greater in the offspring. These differences were maintained in all 32 offspring when compared with 18 controls of similar age, sex, and weight; seven of the 32 offspring had impaired glucose tolerance. These results indicate that young offspring of selected non-insulin dependent diabetics can show extensive metabolic changes including impaired glucose tolerance. These changes are associated with hyperinsulinaemia and hyperglucagonaemia.     

Sticky anaphase aberrations after G2-phase arrest of gamma-irradiated human skin fibroblasts: TP53 independence of formation and TP53 dependence of consequences

We have studied the impact of TP53 status on the extent and nature of chromosome damage seen in human skin fibroblasts after gamma irradiation beyond the G1-phase checkpoint but prior to the G2-phase checkpoint. Mitotic cells were examined in the absence and presence of treatment with nocodazole and the yield of aberrations was scored as a function of time postirradiation. The results revealed substantially greater damage in the absence of nocodazole, indicating that damage was being masked in its presence. While metaphase aberrations were seen exclusively in the presence of nocodazole, anaphase aberrations were seen principally in its absence. Furthermore, these were mostly of an unseparated, or "sticky", type that showed separation of the chromatids in the centromeric region, indicating normal degradation of cohesin, with retention of adhesion further out on the chromatid arms. Using postirradiation BrdU labeling and the absence of nocodazole, we were able to identify mitotic figures up to the third postirradiation mitosis. Analysis of the data revealed that in cells wild-type for TP53 the aberrant anaphases were lost after the first postirradiation mitosis, although they were still found in gradually decreasing amounts into the second and third postirradiation mitoses in E6-expressing cells. The data indicate that the formation of these sticky anaphases is independent of TP53 status, an observation that is consistent with the TP53 independence of transient G2-phase arrest. However, the consequences of the formation of these lesions appear to be very different. In the case of cells wild-type for TP53 this is chronic G1-phase arrest, while in E6 cells it is anaphase catastrophe.     

P450 BM3: the very model of a modern flavocytochrome

Flavocytochrome P450 BM3 is a bacterial P450 system in which a fatty acid hydroxylase P450 is fused to a mammalian-like diflavin NADPH-P450 reductase in a single polypeptide. The enzyme is soluble (unlike mammalian P450 redox systems) and its fusion arrangement affords it the highest catalytic activity of any P450 mono-oxygenase. This article discusses the fundamental properties of P450 BM3 and how progress with this model P450 has affected our comprehension of P450 systems in general.     

Cell death shapes embryonic lineages of the central complex in the grasshopper Schistocerca gregaria

We have investigated cell death in identified lineages of the central complex in the embryonic brain of the grasshopper Schistocerca gregaria. Progeny from these lineages lie in the pars intercerebralis and direct projections to the protocerebral bridge and then the central body via the w, x, y, z tracts. Osmium‐ethyl gallate staining reveals pycnotic cells exclusively in cortical regions, and concentrated specifically within the lineages of the W, X, Y, Z neuroblasts. Minimal cell death occurs in a sporadic, nonpatterned manner, in other protocerebral regions. Immunohistochemistry reveals pycnotic cells express the enzyme cleaved Caspase‐3 in their cytoplasm and are therefore undergoing programmed cell death (apoptosis). The number of pycnotic bodies in lineages of the pars intercerebralis varies with age: small numbers are present in the Y, Z lineages early in embryogenesis (42%), the number peaks at 67–80%, and then declines and disappears late in embryogenesis. Cell death may encompass up to 20% of a lineage at mid‐embryogenesis. Peak cell death occurs shortly after maximum neurogenesis in the Y, Z lineages, and is maintained after neurogenesis has ceased in these lineages. Cell death within a lineage is patterned. Apoptosis is more pronounced among older cells and almost absent among younger cells. This suggests that specific subsets of progeny will be culled from these lineages, and we speculate about the effect of apoptosis on the biochemical profile of such lineages. J. Morphol. 271:949–959, 2010. © 2010 Wiley‐Liss, Inc.     

In vitro induction of mucosa-type dendritic cells by all-trans retinoic acid

Efficient induction of mucosal immunity usually employs nasal or oral vaccination while parenteral immunization generally is ineffective at generating mucosal immune responses. This relates to the unique ability of resident mucosal dendritic cells (DC) to induce IgA switching and to imprint mucosa-specific homing receptors on lymphocytes. Based on the well-established plasticity of the DC system, this study sought to investigate whether peripheral DC could be modulated toward "mucosa-type" DC by treatment with immunomodulatory, and therefore potentially adjuvant-like, factors. In this study, we show that monocyte-derived DCs pretreated with the vitamin A derivative all-trans retinoic acid (RA) indeed acquired several attributes characteristic of mucosal DC: secretion of TGF-beta and IL-6 and the capacity to augment mucosal homing receptor expression and IgA responses in cocultured lymphocytes. Addition of a TGF-beta-neutralizing Ab to cocultures significantly inhibited alpha4beta7 integrin, but not CCR9 mRNA expression by the lymphocytes. Both alpha4beta7 integrin and CCR9 mRNA expression, but not IgA production, were suppressed in the presence of a RA receptor antagonist. None of the observed effects on the lymphocytes were influenced by citral, a retinal dehydrogenase inhibitor, arguing against a role for de novo-synthesized RA. Collectively, our findings identified a novel role for RA as a mucosal immune modulator targeting DC. Our results further demonstrate that DC can act as efficient carriers of RA at least in vitro. Consequently, RA targeting of DC shows potential for promoting vaccine-induced mucosal immune responses via a parenteral route of immunization.     

A comparison of catecholamine-induced internalization of beta-adrenergic receptors and receptor-mediated endocytosis of epidermal growth factor in human astrocytoma cells. Inhibition by phenylarsine oxide

The ligand-induced internalization of beta-adrenergic receptors and the receptor-mediated internalization of epidermal growth factor were blocked, under similar conditions, by phenylarsine oxide (PAO) in human astrocytoma cells (1321N1). The inhibition was not prevented or reversed by monofunctional sulfhydryl agents such as 2-mercaptoethanol or glutathione; however, the inhibitory action of PAO was blocked and reversed by bifunctional thiols such as 2,3-dimercaptoethanol or dithiothreitol. The results are consistent with the interaction of PAO with vicinal sulfhydryl groups to form a stabile ring structure. PAO did not prevent isoproterenol-induced uncoupling (desensitization) of beta-adrenergic receptors even though receptor internalization was completely blocked. The effects of PAO on receptor internalization could not be explained by any action of the trivalent arsenical to lower ATP levels. Ligand binding to both receptors was not detectably altered by PAO under conditions selective for inhibition for endocytosis. The results suggest a common mechanism for internalization of beta-adrenergic receptors and epidermal growth factor by a process that involves vicinal sulfhydryl groups.     

Presence of the major progesterone-induced proteins of the sheep endometrium in fetal fluids

Allantoic and amniotic fluids were collected on Days 60 (n = 3), 100 (n = 4), and 140 (n = 3) of pregnancy. The presence of uterine milk proteins (UTM-proteins) in these samples was evaluated by Ouchterlony immunodiffusion and enzyme-linked immunoabsorbant assay (ELISA). Eight of ten samples of allantoic fluid and three of ten samples of amniotic fluid produced one or two immunoprecipitin bands against antiserum to UTM-proteins. Each band fused with immunoprecipitin bands from UTM-proteins purified from uterine fluid. Data from a semi-quantitative ELISA indicated that allantoic fluid from all ewes and amniotic fluid from six of ten ewes contained immunoreactive UTM-proteins. Concentrations of UTM-proteins in these fluids were not statistically affected by day of gestation (p greater than 0.10), but tended to decline as gestation advanced. Greater concentrations of UTM-proteins were detected in allantoic fluid than in amniotic fluid (p less than 0.05). The physical characteristics of the immunoreactive material in allantoic and amniotic fluids were examined by polyacrylamide gel electrophoresis and Western blotting. The immunoreactive material was found to possess pIs and molecular weights identical to UTM-proteins. These results indicate that fetal fluids contain material that reacts with antiserum to UTM-proteins and has physical properties similar to UTM-proteins. It is likely, therefore, that the UTM-proteins are transported across the placenta during gestation, perhaps to serve some function in the fetal compartment.