Development of a novel method to determine very low density lipoprotein kinetics

Isotopic tracer methods of determining triglyceride-rich lipoprotein (TRL) kinetics are costly, time-consuming, and labor-intensive. This study aimed to develop a simpler and cost-effective method of obtaining TRL kinetic data, based on the fact that chylomicrons compete with large VLDL (VLDL(1); S(f) = 60-400) for the same catalytic pathway. Ten healthy subjects [seven men; fasting triglyceride (TG), 44.3-407.6 mg/dl; body mass index, 21-35 kg/m(2)] were given an intravenous infusion of a chylomicron-like TG emulsion (Intralipid; 0.1 g/kg bolus followed by 0.1 g/kg/h infusion) for 75-120 min to prevent the clearance of VLDL(1) by lipoprotein lipase. Multiple blood samples were taken during and after infusion for separation of Intralipid, VLDL(1), and VLDL(2) by ultracentrifugation. VLDL(1)-apolipoprotein B (apoB) and TG production rates were calculated from their linear increases in the VLDL(1) fraction during the infusion. Intralipid-TG clearance rate was determined from its exponential decay after infusion. The production rates of VLDL(1)-apoB and VLDL(1)-TG were (mean +/- SEM) 25.4 +/- 3.9 and 1,076.7 +/- 224.7 mg/h, respectively, and the Intralipid-TG clearance rate was 66.9 +/- 11.7 pools/day. Kinetic data obtained from this method agree with values obtained from stable isotope methods and show the expected relationships with indices of body fatness and insulin resistance (all P < 0.05). The protocol is relatively quick, inexpensive, and transferable to nonspecialist laboratories.     

Characterization of insulin/IGF hybrid receptors: contributions of the insulin receptor L2 and Fn1 domains and the alternatively spliced exon 11 sequence to ligand binding and receptor activation

The IR (insulin receptor) and IGFR (type I insulin-like growth factor receptor) are found as homodimers, but the respective pro-receptors can also heterodimerize to form insulin-IGF hybrid receptors. There are conflicting data on the ligand affinity of hybrids, and especially on the influence of different IR isoforms. To investigate further the contribution of individual ligand binding epitopes to affinity and specificity in the IR/IGFR family, we generated hybrids incorporating both IR isoforms (A and B) and IR/IGFR domain-swap chimaeras, by ectopic co-expression of receptor constructs in Chinese hamster ovary cells, and studied ligand binding using both radioligand competition and bioluminescence resonance energy transfer assays. We found that IR-A-IGFR and IR-B-IGFR hybrids bound insulin with similar relatively low affinity, which was intermediate between that of homodimeric IR and homodimeric IGFR. However, both IR-A-IGFR and IR-B-IGFR hybrids bound IGF-I and IGF-II with high affinity, at a level comparable with homodimeric IGFR. Incorporation of a significant fraction of either IR-A or IR-B into hybrids resulted in abrogation of insulin- but not IGF-I-stimulated autophosphorylation. We conclude that the sequence of 12 amino acids encoded by exon 11 of the IR gene has little or no effect on ligand binding and activation of IR-IGFR hybrids, and that hybrid receptors bind IGFs but not insulin at physiological concentrations regardless of the IR isoform they contained. To reconstitute high affinity insulin binding within a hybrid receptor, chimaeras in which the IGFR L1 or L2 domains had been replaced by equivalent IR domains were co-expressed with full-length IR-A or IR-B. In the context of an IR-A-IGFR hybrid, replacement of IR residues 325-524 (containing the L2 domain and part of the first fibronectin domain) with the corresponding IGFR sequence increased the affinity for insulin by 20-fold. We conclude that the L2 and/or first fibronectin domains of IR contribute in trans with the L1 domain to create a high affinity insulin-binding site within a dimeric receptor.     

Transfer of PR1-specific T-cell clones from donor to recipient by stem cell transplantation and association with GvL activity

BACKGROUND: The curative effects of GvL following transfer of donor-derived T cells during allogeneic stem cell transplantation (SCT) are well established. However, little is known about the nature, origin and kinetics of the anti-leukemic T-cell responses involved. METHODS: We used quantitative real-time PCR (qRT-PCR) for interferongamma mRNA production (IFN-gamma) and PR1/HLA-A*0201 tetramer staining to detect PR1-specific CD8+ T-cell activity in a donor and a patient with CML. Unbiased strand switch anchored RT-PCR was used to further characterize specific clones in PR1 sorted CD8+ T-cell populations. RESULTS: We identified PR1-specific CD8(+) T-cell clones from a donor pre-transplant, and demonstrated their transfer in the recipient's blood post-SCT using molecular tracking of Ag-specific T-cell receptors. PR1-specific CD8(+) T-cell populations were polyclonal, with a range of functional avidities for cognate Ag, and displayed predominantly effector memory phenotype early post-SCT, suggesting active stimulation in vivo. Expansion of these PR1-specific CD8(+) T-cell clones in the recipient was followed by complete remission of CML. DISCUSSION: This report represents the first direct demonstration that PR1-specific CD8(+) T-cell clones can be transferred during SCT, and supports the feasibility of pre-transplant vaccination strategies that aim to boost the number of anti-leukemic T cells in the graft.     

Demographic parameters of wrinkling aphid of pistachio leaf, Forda hirsuta Mordv. (Hem.:Pemphigidae) insitu of Rafsanjan's orchards

Wrinkling aphid of pistachio leaf, Forda hirsuta Mordv. (Hem.:Pemphigidae) is one of the pests of pistachio trees. This aphid caused the shrinkage, thickening, and changing the color of the pistachio leaves. Since insect feeds from leave edges, the thick and rolled upward wrinkles were formed, which its green color turned into red. Therefore, its economical damages are out of direct feeding from plant extraction, twisting pistachio leaves, and the decrease of photosynthesis. In this research two orchards and 10 trees that each of them were selected in Rafsanjan region and 58 fundatrix galls, 120 nymphal galls were marked and the demographic parameters for apterus parthenogenesis female of this aphid were calculated via daily observations. The results indicated that intrinsic rates of increase (r) for 1, 2 and 3 generations were 0.01, 0.0638 and 0.0575 femal/femal/days respectively, Doubling time (DT) were 69.31, 10.52 and 12.04 days, respectively, net fecundity rates were 1.71, 11.5 and 7.37 femal/femal/days, respectively, Net fertility rates were 1.11, 8.87 and 5.01 days, respectively, and mean generation times (Tc) were calculated to be 31.5, 32.2 and 31.87 days, respectively. Other reproductive parameters such as gross hatch rate, gross fecundity rate, gross fertility rate, mean age gross fecundity and fertility, mean age net fecundity and fertility, mean age hatch, finite rate of increase (lambda), intrinsic birth rate (b) intrinsic death rate (d) and daily reproductive rate were also calculated. The results revealed that population parameters especially r in the first and second generations were lowest and highest, respectively and mean longevity of fundatrix was 30 days and the born nymphs made separate galls in the edge of pistachio leaves.     

Regulation of DAPK1 by Natural Products: An Important Target in Treatment of Stroke

Neurochemical Research - Stroke is a sudden neurological disorder that occurs due to impaired blood flow to an area of the brain. Stroke can be caused by the blockage or rupture of a blood vessel...     

Fingerling production and stock enhancement of Mahisefid (Rutilus frisii kutum) lessons for others in the south of Caspian Sea

Rutilus frisii kutum (Kamensky 1901) is one of the economically important fishes that migrate for spawning to rivers in the Caspian Sea. However, the fish populations have slowly decreased in recent years. The declining of these resources has resulted from some activities by the Iranian Fisheries Organization (IFO is responsible for stock enhancement) to catch some broodstocks of Rutilus frisii kutum from their natural spawning rivers. The broodstocks are caught for artificial propagation of the fish. Artificial propagations are carried out every year to produce fingerlings to be released into the rivers in the Caspian Sea. In recent years, total catch of this fish have greatly fluctuated due to the disruption of the natural spawning grounds and over fishing. The substantial reduction to 1,298 metric tons, the lowest total catch reported in 1984–1985, could be due to over-exploitation of the fishery resources. However, the total catch has increased after the fingerlings release programs started in 1979. The total numbers of Rutilus frisii kutum fingerlings released had increased from 12 million to 225 million in 2002, to 155 million pieces in 2003, to 179 million pieces in 2004, 229 million pieces in 2005, 174 million pieces in 2006, 262 million pieces in 2007 and 187.1 in 2008. The total catch was also increased from 6,417 metric ton to 8,984 metric ton, to 7,036 metric ton, to 9,631 metric ton and 16,117, 17,196, 14,835 in years 2002, 2003, 2004, 2005, 2006, 2007 and 2008, respectively.     

Salt-stress induced physiological and proteomic changes in tomato (Solanum lycopersicum) seedlings

Soil salinity is one of the major abiotic stress limiting crop productivity and the geographical distribution of many important crops worldwide. To gain a better understanding of the salinity stress responses at physiological and molecular level in cultivated tomato (Solanum lycopersicum. cv. Supermarmande), we carried out a comparative physiological and proteomic analysis. The tomato seedlings were cultivated using a hydroponic system in the controlled environment growth chamber. The salt stress (NaCl) was applied (0, 50, 100, 150 and 200?mM), and maintained for 14 days. Salt treatment induced a plant growth reduction estimated as fresh-dry weight. Photosynthetic pigments (chlorophyll a, b) content of NaCl-treated tomato plants was significantly decreased as the salinity level increased. Proline accumulation levels in leaf and root tissues increased significantly with increasing NaCl concentration. Relative electrolyte leakage known as an indicator of membrane damage caused by salt stress was increased proportionally according to the NaCl concentrations. Roots of control and salt-stressed plants were also sampled for phenol protein extraction. Proteins were separated by two-dimensional gel electrophoresis (2-DGE). Several proteins showed up- and downregulation during salt stress. MALDI-TOF/MS analysis and database searching of some of the identified proteins indicated that the proteins are known to be in a wide range of physiological processes, that is, energy metabolism, ROS (reactive oxygen species) scavenging and detoxification, protein translation, processing and degradation, signal transduction, hormone and amino acid metabolism, and cell wall modifications. All proteins might work cooperatively to reestablish cellular homeostasis under salt stress, water deficiency, and ionic toxicity.