Autoimmune islet destruction in spontaneous type 1 diabetes is not beta-cell exclusive

Pancreatic islets of Langerhans are enveloped by peri-islet Schwann cells (pSC), which express glial fibrillary acidic protein (GFAP) and S100beta. pSC-autoreactive T- and B-cell responses arise in 3- to 4-week-old diabetes-prone non-obese diabetic (NOD) mice, followed by progressive pSC destruction before detectable beta-cell death. Humans with probable prediabetes generate similar autoreactivities, and autoantibodies in islet-cell autoantibody (lCA) -positive sera co-localize to pSC. Moreover, GFAP-specific NOD T-cell lines transferred pathogenic peri-insulitis to NOD/severe combined immunodeficient (NOD/SCID) mice, and immunotherapy with GFAP or S100beta prevented diabetes. pSC survived in rat insulin promoter Iymphocytic choriomeningitis virus (rip-LCMV) glycoprotein/CD8+ T-cell receptor(gp) double-transgenic mice with virus-induced diabetes, suggesting that pSC death is not an obligate consequence of local inflammation and beta-cell destruction. However, pSC were deleted in spontaneously diabetic NOD mice carrying the CD8+/8.3 T-cell receptor transgene, a T cell receptor commonly expressed in earliest islet infiltrates. Autoimmune targeting of pancreatic nervous system tissue elements seems to be an integral, early part of natural type 1 diabetes.     

Increasing intracellular cAMP and cGMP inhibits cadmium-induced oxidative stress in rat submandibular saliva

The effect of cadmium on induction of oxidative stress in rat submandibular saliva and protective role of increasing intracellular cAMP and cGMP by use of specific phosphodiesterase inhibitors, theophylline and sildenafil were investigated. Pure submandibular saliva was collected intraorally by micro polyethylene cannula from anaesthetized rats using pilocarpine as secretagogue. Acute administration of cadmium (10 mg/kg) caused significant oxidative stress by increasing lipid peroxidation by-products (thiobarbituric reactive substances, TBARS) and decreasing total thiols and total antioxidant power of the saliva. Concurrent therapy of rats by theophylline (25 mg/kg) and sildenafil (5 mg/kg) prevented cadmium-induced oxidative stress in saliva. Theophylline and sildenafil inhibited cadmium-induced increase in lipid peroxidation and decrease in total thiols and antioxidant power. It is concluded that cadmium administration results in oxidative stress in rat submandibular saliva, which can be protected by concurrent administration of specific cyclic nucleotide phosphodiesterase inhibitors.     

Comparison of the Four Proposed Apgar Scoring Systems in the Assessment of Birth Asphyxia and Adverse Early Neurologic Outcomes

Objectives

To compare the Conventional, Specified, Expanded and Combined Apgar scoring systems in predicting birth asphyxia and the adverse early neurologic outcomes.

Methods

This prospective cohort study was conducted on 464 admitted neonates. In the delivery room, after delivery the umbilical cord was double clamped and a blood samples was obtained from the umbilical artery for blood gas analysis, meanwhile on the 1- , 5- and 10- minutes Conventional, Specified, Expanded, and Combined Apgar scores were recorded. Then the neonates were followed and intracranial ultrasound imaging was performed, and the following information were recorded: the occurrence of birth asphyxia, hypoxic Ischemic Encephalopathy (HIE), intraventricular hemorrhage (IVH), and neonatal seizure.

Results

The Combined-Apgar score had the highest sensitivity (97%) and specificity (99%) in predicting birth asphyxia, followed by the Specified-Apgar score that was also highly sensitive (95%) and specific (97%). The Expanded-Apgar score was highly specific (95%) but not sensitive (67%) and the Conventional-Apgar score had the lowest sensitivity (81%) and low specificity (81%) in predicting birth asphyxia. When adjusted for gestational age, only the low 5-minute Combined-Apgar score was independently associated with the occurrence of HIE (B = 1.61, P = 0.02) and IVH (B = 2.8, P = 0.01).

Conclusions

The newly proposed Combined-Apgar score is highly sensitive and specific in predicting birth asphyxia and also is a good predictor of the occurrence of HIE and IVH in asphyxiated neonates.     

Inhibition of oxidative stress-induced amyloid β formation in NT2 neurons by culture filtrate of a strain of Streptomyces antibioticus

Actinomycetes isolated from Iran soil habitats were tested for the capacity to produce compounds which can protect neurons from cell death generated by oxidative stress in NT2 neurons. Confirmation of our initial hit was accomplished via the determination of amyloid β level using the enzyme-linked immunosorbent assay test. The most interesting amyloid β formation inhibitor discovered in our study was a secondary metabolite which was produced by strain HM45. This bioactive strain was identified as a strain of Streptomyces antibioticus DSM 40234 using polyphasic approach. The strain HM45 was deposited in Deutsche Sammlung von Mikroorganismen und Zellkulturen as S. antibioticus DSM 41955 and University of Tehran Microorganisms Sollection as S. antibioticus UTMC 00105. This work is the first report on efficiency of an actinomycete metabolite in prohibition of neurons death caused by amyloid β formation.     

Physiological responses to NaCl stress in three wild species of potato in vitro

In this study, responses of wild species of potato to NaCl stress were investigated in vitro. In S. stoloniferum and S. bulbosum, length of the shoot, fresh and dry weight, photosynthetic pigments, K⁺ concentration, K⁺/Na⁺ ratio, ascorbate pool, anthocyanin, and phenolic and flavonoid compounds were decreased in response to salinity. In these species, salinity increased the level of Na⁺, lipid peroxidation, proline and ion leakage percentage. In S. acaule, the length of the shoot, and fresh and dry weight were not affected by salinity. Photosynthetic pigments, Na⁺ concentration, proline, flavonoid and phenolic compounds quantities were increased and K⁺/Na⁺ ratio were decreased. K⁺ concentration, lipid peroxidation, ascorbate pool, anthocyanin and ion leakage were not changed by NaCl stress. Superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase and catalase activities were increased in all species. The results suggest that the non-enzymatic antioxidant capacity in S. acaule (salt tolerant) is more important than the enzymatic antioxidant capacity in comparison with the other species.     

Increased expression of recombinant human tissue plasminogen activator in Leishmania tarentolae

Recombinant tissue plasminogen activator (rt-PA) is one of the most important thrombolytic agents for treating cardiovascular obstructions such as stroke. Glycoprotein rt-PA is a serine protease, consisting of 527 amino acids of which 35 are cysteine residues. A variety of recombinant protein expression systems have been developed for heterologous gene expression in prokaryotic and eukaryotic hosts. In recent years, Leishmania tarentolae has been considered because of its safety aspects and special attributes in expression of complex proteins. In this study, two expression cassettes, each one including two copies of t-PA cDNA, were used for integration into the L. tarentolae genome by electroporation. Transformed clones were selected in the presence of appropriate antibiotics. Expression of active rt-PA was confirmed by Western blot and Zymography tests. Real-time PCR analysis was applied to investigate the presence of multiple t-PA gene copies in the parasite genome. Correlation of t-PA gene dosage and production rate was confirmed with real-time PCR. It was shown that the expression level of rt-PA in L. tarentolae is at least 480 IU/mL of culture media. This concentration of rt-PA is seven times higher than what was reported in previous studies in L. tarentolae and some other eukaryotic systems.     

Long-term stability of marker gene expression in Prunus subhirtella: a model fruit tree species

Transgenic trees currently are being produced by Agrobacterium-mediated transformation and biolistics. Since trees are particularly suited for long-term evaluations of the impact of the technology, Prunus subhirtella autumno rosa (PAR) was chosen as model fruit tree species and transformed with a reporter gene (uidA) under the control of the 35S promoter. Using Southern and GUS fluorometric techniques, we compared transgene copy numbers and observed stability of transgene expression levels in 34 different transgenic plants, grown under in vitro, greenhouse and screenhouse conditions, over a period of 9 years. An influence of grafting on gene expression was not observed. No silenced transgenic plant was detected. Overall, these results suggest that transgene expression in perennial species, such as fruit trees, remains stable in time and space, over extended periods and in different organs, confirming the value of PAR as model species to study season-dependent regulation in mature stone fruit tissues. While the Agrobacterium-derived Prunus transformants contained one to two copies of the transgenes, 91% of the transgenic events also contained various lengths of the bacterial plasmid backbone, indicating that the Agrobacterium-mediated transformation is not as precise as previously perceived. The implications for public acceptance and future applications are discussed.     

Distinct functions of the Drosophila Nup153 and Nup214 FG domains in nuclear protein transport

The phenylanine-glycine (FG)-rich regions of several nucleoporins both bind to nuclear transport receptors and collectively provide a diffusion barrier to the nuclear pores. However, the in vivo roles of FG nucleoporins in transport remain unclear. We have inactivated 30 putative nucleoporins in cultured Drosophila melanogaster S2 cells by RNA interference and analyzed the phenotypes on importin alpha/beta-mediated import and CRM1-dependent protein export. The fly homologues of FG nucleoporins Nup358, Nup153, and Nup54 are selectively required for import. The FG repeats of Nup153 are necessary for its function in transport, whereas the remainder of the protein maintains pore integrity. Inactivation of the CRM1 cofactor RanBP3 decreased the nuclear accumulation of CRM1 and protein export. We report a surprisingly antagonistic relationship between RanBP3 and the Nup214 FG region in determining CRM1 localization and its function in protein export. Our data suggest that peripheral metazoan FG nucleoporins have distinct functions in nuclear protein transport events.