谷氨酸诱导体外培养的鸡胚脊髓神经细胞释放NO

用鸡胚脊髓神经细胞的原代培养,测定细胞中亚硝酸盐的含量,研究了谷氨酸(Glu)对原代培养神经细胞中NO的影响。结果表明,谷氨酸作用于原代培养的鸡胚脊髓神经细胞,在诱导神经细胞释放乳酸脱氢酶(LDH)的同时,还可诱导细胞释放一氧化氮(NO)。如先用NO合成酶抑制剂L-NOARG作用细胞,再加入Glu,则发现L-NOARG能降低Glu导致的培养液中LDH活性升高。提示NO可能参与介导Glu的神经毒性作用。     

Predicting the experience of dentinal caries or restorative dental treatment in adolescents using D1 and D3 visual caries assessments

Standardised epidemiological caries assessments used in oral health surveys have been shown to be poor at predicting whether a tooth surface will be treated restoratively when a patient visits a dentist. However, it has been argued that oral health surveys may be more relevant in determining needs at the level of an individual or groups of individuals. The objective of this study was to determine the discriminatory power of visual caries assessments at two thresholds (D₁ & D₃) in adolescents of average age 12.1 years to predict experience of dentinal caries 3 years later or the experience of restorative treatment (not re‐treatment) during the 3‐year period. The data was derived from a prospective 3‐year longitudinal study in which the dental care provided by 41 dentists for 403 adolescents was monitored. Dental caries experience was monitored by annual standardised assessments of caries undertaken by a single trained examiner. ROC analysis showed that caries assessed visually at the D₁ threshold in 12‐year‐olds was a better predictor (P < 0.001) of experiencing some dentinal caries after 3 years (Az = 0.781) than was caries assessed visually at D₃ threshold in 12‐year‐olds (Az = 0.670). Assessing caries visually at either the D₁ or the D₃ threshold had no discriminatory power for predicting whether an individual would experience some restorative treatment during the ensuing 3‐year period (Az for D₁ = 0.507; Az for D₃ = 0.518).     

The fourth genus in the Orthomyxoviridae: sequence analyses of two Thogoto virus polymerase proteins and comparison with influenza viruses

The tick-borne Thogoto virus (THOV) is the type species of a newly recognized fourth genus, Thogotovirus, in the family Orthomyxoviridae. Because of the distant relationship of THOV with the influenza viruses, determination of its genomic information can potentially be used to identify important domains in influenza virus proteins. We have determined the complete nucleotide sequence of the second longest RNA segment of THOV. The molecule comprises 2212 nucleotides with a single large open reading frame encoding a protein of 710 amino acids, estimated M_r 81 284. The protein shares 77% amino acid similarity with the PB1-like protein of Dhori virus, a related tick-borne virus, and 50–53% with the PB1 polymerase proteins of influenza virus A, B and C. All the motifs characteristic of RNA-dependent polymerases were identified including the SSDD motif common to all RNA-dependant RNA polymerases, indicating that the THOV protein is functionally analogous to the influenza virus PB1 proteins and involved in chain elongation. We also report the corrected sequence of the third longest RNA segment of THOV, encoding a protein which shares 44–47% amino acid similarity with the PA-like polymerase proteins of influenza virus A, B and C. The biological significance of conserved domains in these orthomyxovirid proteins is discussed.     

Insulin and epinephrine effects on heart glycogen synthase and phosphorylase activity.

The effect of intravenous epinephrine on heart glycogen synthase and phosphorylase systems in control and insulin-pretreated rats was studied. The percent of synthase in the I form decreased rapidly after epinephrine treatment but the change was small and sometimes not significant. In insulin-pretreated rats in which the percent synthase I was increased, epinephrine produced a definate and highly significant decrease. There was a simultaneous increase in percent phosphorylase a in both groups. The synthase and phosphorylase responses were statiscally significant at 2.5 mug epinephrine/kgor more. These data are compatible with a mechanism in which protein kinase is activated by an increased cAMP concentration and affects both the synthase and phosphorylasesystems simultaneously. Propranolol blocked the epinephrine effects on cAMP, synthase I, and phosphorylase a. Although insulin had little effect on the response ofthe synthase and phosphorylase systems to epinephrine, it nealry completely blocked glycogen degradation. The mechanism is unknown, but it appears to be due to an inhibition of phosphorylase a catalytic activity in vivo. Acetylcholine had no effect on synthase I, phosphorylase a, or cAMP in control or in insulin-pretreated animals.     

Maternal serum alpha-fetoprotein and altitude

Maternal serum alpha-fetoprotein (MS-alphaFP) testing is widely used to screen for fetal defects. MS-alphaFP concentrations are affected by a number of variables such as gestational age, maternal weight, number of fetuses, race, and insulin-dependent diabetes. Undefined geographic factors may also influence MS-alphaFP. We have examined the effect of altitude in a sample of 1063 MS-alphaFP results selected to span a range of altitudes. The study sample was subjected to linear regression with and without a term for altitude, and multiple-of-the-median (MoM) values were calculated before and after adjusting for altitude. The median MS-alphaFP was found to decrease an average of 1 ng/mL for every 1100 ft increase in altitude, a change approximately equivalent to that seen with an increase in maternal weight of 6 lb. Adjusting for altitude resulted in the reclassification of 36 of 1063 patient results (3.4%), although the clinical utility of this adjustment remains unexamined.     

Ribosome display and affinity maturation: from antibodies to single V-domains and steps towards cancer therapeutics

Vascular endothelium is an important site for a wide array of immunological processes such as inflammation, atherosclerosis and allograft rejection. Culture methods of mouse vascular endothelium would provide an important in vitro correlate to immunological murine in vivo models. We describe a simple method to culture mouse vascular endothelium from thoracic aorta. Our cultured cells express typical phenotypic (CD105, CD31, CD106), morphological and ultrastructural (intercellular junctions, Weibel-Palade bodies) markers of vascular endothelium. They also possess functional receptors for uptake and processing of acetylated low-density lipoproteins. The mouse vascular endothelium within our system expresses high levels of MHC class I and MHC class II after activation with IFN-gamma. In addition, these cells express the accessory molecules CD80 and CD54, while they lack constitutive expression of CD86 and CD40, providing them the means to function as antigen presenting cells. Alloreactive CD4(+) and CD8(+) T lymphocytes demonstrate evidence of DNA synthesis after co-culture with activated vascular endothelium indicating their commitment to proliferation. In conclusion, we describe a simple culture system to isolate and grow mouse vascular endothelium, which provides a powerful tool to study biological interactions in vitro.     

Direct current pulse elicits basilar membrane vibration in guinea pigs

Since the lagos, the elec~lity of the cochleahas attheted much attention. It has been demonshatedthat the outer air cells (OHCs) Play a key role in theeleC~hty of the COChiea. EvanS et al if] found thatthe OHCs exhiliited in cairo length change in a Voltagedependent manner upon electric stimulation, applying thatOHCs assess electIO~mecbocal ~sduchon ability,which motivates the intwry into the causality betWeenOHC electIDmotility and basilar membrane (BM) vibrationand fulther, into th…