Maternal corticotropin-releasing hormone and habituation in the human fetus

Elevated concentrations of maternal corticotrophin-releasing hormone (CRH) during the 2nd and early 3rd trimester of human pregnancy are associated with spontaneous preterm birth, but the effects of maternal CRH on the fetus are unknown. Maternal plasma was collected for analysis of CRH concentration, m = 156.24 +/- 130.91 pg/ml, from 33 pregnant women during Weeks 31-33 of gestation. Immediately after collection of plasma, fetal heart rate (FHR) measures were obtained in response to a challenge with a series of vibroacoustic stimuli. Fetuses of mothers with highly elevated CRH did not respond significantly to the presence of a novel stimulus in a repeated series, p = 0.016. These effects on the FHR response were not related to parity, fetal gender, medical (antepartum) risk, or eventual birth outcomes. Impaired dishabituation in these fetuses of mothers with high concentrations of CRH suggests that neurological systems rich with CRH receptors that support learning and memory, such as parahippocampal regions, may be targets for maternal/placental CRH, with implications for fetal neurological development.     

Fractionation and characterization of the immunosuppressive substance in crude extracellular products released by Streptococcus intermedius.

The noncytotoxic immunosuppressive substance detected in crude extracellular products of Streptococcus intermedius (CEP-SI) was fractionated by two steps of preparative isoelectric focusing in sucrose gradients using ampholytes of pH range from 3.5 to 6 and 4 to 5, respectively. The in vitro and in vivo suppressor effects of the most highly purified fraction of CEP-Si, designated fraction 3' (F3'EP-Si), corresponded well with those of the original CEP-Si. F3'EP-Si was sensitive to the effects of alpha, gamma, and delta chymotrypsin, trypsin, and heating. It contained approximately 1% of the total amount of protein found in the original CEP-Si, corresponding to a single band on analytical isoelectric focusing, stainable by Coomassie Blue and of isoelectric point of 4.25. The absorption spectrum of F3'EP-Si had a maximum at 260 nm but its biological activity was resistant to deoxyribonuclease and ribonuclease A and it did not contain material stainable by methylene blue. It was also resistant to neuraminidase and did not contain material stainable by periodic acid schiff. We conclude that the substance responsible for the suppressor activity of CEP-Si is a protein of molecular weight approximately 90,000, which adheres to Sephadex of cellulose acetate and forms complexes with other, nonactive constituents of CEP-Si.     

复发前后多形性胶质母细胞瘤的等位基因谱分析

目的：研究多形性胶质母细胞瘤（glioblastoma multiforme,GBM)复发前后的分子遗传学变化，了解基因组范围内哪些染色体区域可能与GBM复发有关。方法：应用聚合酶链反应技术为基础的杂合性丢失（loss of heterozygosity,LOH)分析法，采用荧光标记的引物和377型DNA序列自动分析仪，检测了1例复发前后GBM所有22对常染色体上多达382个微卫星位点。相邻2个微卫星位点之间的平均距离为10cM。结果：对原发肿瘤标本的等位基因谱分析显示，染色体9p21上D9S157位点和10q21.3-26.3上D10S537、D10S185、D10S192、D10S597、D10S587、D10S217位点存在LOH。对复发肿瘤标本的研究显示，不但9p21和10q21.3-26.3上LOH的范围扩大，而且在其它多条染色体上也出现了LOH（包括1q,7p,7q,21q,20p,20q,10p,19p,19q)。结论：染色体9p和10q可能在该例GBM的发生中起着重要作用。尽管该病例复发前后的病理诊断相同，复发后GBM存在着更广泛的分子遗传学异常改变，可能伴随着更多肿瘤抑制基因的失活。     

Integration of [U-13C]glucose and 2H2O for quantification of hepatic glucose production and gluconeogenesis

Glucose metabolism in five healthy subjects fasted for 16 h was measured with a combination of [U-13C]glucose and 2H2O tracers. Phenylbutyric acid was also provided to sample hepatic glutamine for the presence of 13C-isotopomers derived from the incorporation of [U-13C]glucose products into the hepatic Krebs cycle. Glucose production (GP) was quantified by 13C NMR analysis of the monoacetone derivative of plasma glucose following a primed infusion of [U-13C]glucose and provided reasonable estimates (1.90 +/- 0.19 mg/kg/min with a range of 1.60-2.15 mg/kg/min). The same derivative yielded measurements of plasma glucose 2H-enrichment from 2H2O by 2H NMR from which the contribution of glycogenolytic and gluconeogenic fluxes to GP was obtained (0.87 +/- 0.14 and 1.03 +/- 0.10 mg/kg/min, respectively). Hepatic glutamine 13C-isotopomers representing multiply-enriched oxaloacetate and [U-13C]acetyl-CoA were identified as multiplets in the 13C NMR signals of the glutamine moiety of urinary phenylacetylglutamine, demonstrating entry of the [U-13C]glucose tracer into both oxidative and anaplerotic pathways of the hepatic Krebs cycle. These isotopomers contributed 0.1-0.2% excess enrichment to carbons 2 and 3 and approximately 0.05% to carbon 4 of glutamine.     

Type 2 diabetes gene TCF7L2 polymorphism is not associated with fetal and postnatal growth in two birth cohort studies

Background  

An inverse association between birth weight and the risk of developing type 2 diabetes (T2D) in adulthood has been reported. This association may be explained by common genetic variants related to insulin secretion and resistance, since insulin is the most important growth factor in fetal life. The objective of this study was to examine whether T2D gene polymorphism TCF7L2 rs7903146 is associated with growth patterns from fetal life until infancy.     

Impact of viral selected mutations on T cell mediated immunity in chronically evolving and self limiting acute HCV infection

The ability of HCV to mutate in response to cytotoxic T lymphocyte (CTL) pressure is increasingly recognized, but the influence of such a mechanism in viral persistence and final disease outcome has not been ascertained. In this study, we performed a detailed longitudinal analysis of cell mediated immunity and HCV evolution in two self limiting and two chronically evolving HCV acutely infected patients, one of whom transiently controlled viremia. Aminoacid mutations in immunodominant regions of viruses were observed in all patients, although they conferred viral escape from CTL responses only in chronically infected individuals. Resurgence of viremia coincided with the replacement of the original virus quasispecies with mutant viruses that had escaped recognition by primary CD8⁺ T cell responses and infection persisted in the presence of variant viruses which were less efficiently recognized by preexisting and de novo induced T cell responses.     

Role of a novel tetrodotoxin-resistant sodium channel in the nitrergic relaxation of corpus cavernosum from the South American rattlesnake Crotalus durissus terrificus

IntroductionCoitus in snakes may last up to 28 hours; however, the mechanisms involved are unknown.AimTo evaluate the relevance of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-phosphodiesterase type 5 (PDE5) system in snake corpus cavernosum reactivity.MethodsHemipenes were removed from anesthetized South American rattlesnakes (Crotalus durissus terrificus) and studied by light and scanning electronic microscopy. Isolated Crotalus corpora cavernosa (CCC) were dissected from the non-spiny region of the hemipenises, and tissue reactivity was assessed in organ baths.Main Outcome MeasuresCumulative concentration-response curves were constructed for acetylcholine (ACh), sodium nitroprusside (SNP), 5-cyclopropyl-2-[1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4-ylamine (BAY 41-2272), and tadalafil in CCC precontracted with phenylephrine. Relaxation induced by electrical field stimulation (EFS) was also done in the absence and presence of N^ω nitro-L-arginine methyl ester (L-NAME; 100 µM), 1H-[1, 2, 4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 µM) and tetrodotoxin (TTX; 1 µM).ResultsThe hemipenes consisted of two functionally concentric corpora cavernosa, one of them containing radiating bundles of smooth muscle fibers (confirmed by α-actin immunostaining). Endothelial and neural nitric oxide synthases were present in the endothelium and neural structures, respectively; whereas soluble guanylate cyclase and PDE5 were expressed in trabecular smooth muscle. ACh and SNP relaxed isolated CCC, with the relaxations being markedly reduced by L-NAME and ODQ, respectively. BAY 41-2272 and tadalafil caused sustained relaxations with potency (pEC₅₀) values of 5.84 ± 0.17 and 5.10 ± 0.08 (N = 3–4), respectively. In precontracted CCC, EFS caused frequency-dependent relaxations that lasted three times longer than those in mammalian CC. Although these relaxations were almost abolished by either L-NAME or ODQ, they were unaffected by TTX. In contrast, EFS-induced relaxations in marmoset CC were abolished by TTX.ConclusionsRattlesnake CC relaxation is mediated by the NO-cGMP-PDE5 pathway in a manner similar to mammals. The novel TTX-resistant Na channel identified here may be responsible for the slow response of smooth muscle following nerve stimulation and could explain the extraordinary duration of snake coitus. Capel RO, Mónica FZ, Porto M, Barillas S, Muscará MN, Teixeira SA, Arruda AMM, Pissinatti, L, Pissinatti A, Schenka AA, Antunes E, Nahoum C, Cogo JC, de Oliveira MA, and De Nucci G. Role of a novel tetrodotoxin-resistant sodium channel in the nitrergic relaxation of corpus cavernosum from the South American rattlesnake Crotalus durissus terrificus.     

ASC and NLRP3 impair host defense during lethal pneumonia caused by serotype 3 Streptococcus pneumoniae in mice

Streptococcus (S.) pneumoniae is the most common cause of community‐acquired pneumonia. The Nod‐like receptor family pyrin domain containing 3 (NLRP3) inflammasome, consisting of NLRP3, ASC (the adaptor apoptosis‐associated speck‐like protein containing a CARD) and caspase‐1, has been implicated in protective immunity during pneumonia induced by high doses of S. pneumoniae serotype 2. Here we investigated the role of the NLRP3 inflammasome in the host response during lethal airway infection with a low dose of serotype 3 S. pneumoniae. Mice were euthanized at predefined endpoints for analysis or observed in survival studies. In additional studies, Tlr2^?/?/Tlr4^?/? mice and Myd88^?/? mice incapable of Toll‐like receptor signaling were studied. In stark contrast with existing literature, both Nlrp3^?/? and Asc^?/? mice showed a strongly improved host defense, as reflected by a markedly reduced mortality rate accompanied by diminished bacterial growth and dissemination. Host defense was unaltered in Tlr2^?/?/Tlr4^?/? mice and Myd88^?/? mice. These results show that the NLRP3 inflammasome impairs host defense during lethal pneumonia caused by serotype 3 S. pneumoniae. Our findings challenge the current paradigm that proximal innate detection systems are indispensable for an adequate host immune response against bacteria.