bluuebunny/crossref_metadata_2025 huggingface dataset:
A production inventory model with deteriorating items and shortages
Authors: Samanta G.P. , Roy Ajanta
Published: November 2006

A continuous production control inventory model for deteriorating items with shortages is developed. A number of structural properties of the inventory system are studied analytically. The formulae for the optimal average system cost, stock level, backlog level and production cycle time are derived when the deterioration rate is very small. Numerical examples are taken to illustrate the procedure of finding the optimal total inventory cost, stock level, backlog level and production cycle time. Sensitivity analysis is carried out to demonstrate the effects of changing parameter values on the optimal solution of the system.
Decision making in reverse logistics using system dynamics
Authors: Georgiadis P. , Vlachos D.
Published: November 2006

Reverse logistics is a modern field of consideration, research and study, providing helpful information on the operation of the closed-loop supply chain. Although the starting point of this field is traced back to the early 90?s, no standard method has been suggested, neither prevailed. The purpose of this paper is to introduce a new approach on the study of reverse logistics. It is actually a review on how System Dynamics (SD) can be a helpful tool when it is used in the reverse logistics field. The paper explains the basic theory of the system modeling and next it utilizes the reverse logistics model. Finally, an illustrative example shows how SD modeling can be used to produce a powerful long-term decision-making tool.
A parametric visualization software for the assignment problem
Authors: Papamanthou Charalampos , Paparrizos Konstantinos , Samaras Nikolaos
Published: November 2006

In this paper we present a parametric visualization software used to assist the teaching of the Network Primal Simplex Algorithm for the assignment problem (AP). The assignment problem is a special case of the balanced transportation problem. The main functions of the algorithm and design techniques are also presented. Through this process, we aim to underline the importance and necessity of using such educational methods in order to improve the teaching of Computer Algorithms.
Production inventory policy under a discounted cash flow
Authors: Su Chao-Ton , Lin Cheng-Wang
Published: November 2006

This paper presents an extended production inventory model in which the production rate at any instant depends on the demand and the inventory level. The effects of the time value of money are incorporated into the model. The demand rate is a linear function of time for the scheduling period. The proposed model can assist managers in economically controlling production systems under the condition of considering a discounted cash flow. A simple algorithm computing the optimal production-scheduling period is developed. Several particular cases of the model are briefly discussed. Through numerical example, sensitive analyses are carried out to examine the effect of the parameters. Results show that the discount rate parameter and the inventory holding cost have a significant impact on the proposed model.
Laguerre-like methods for the simultaneous approximation of polynomial multiple zeros
Authors: Petkovic Miodrag , Rancic Lidija , Milosevic Dusan
Published: November 2006

Two new methods of the fourth order for the simultaneous determination of multiple zeros of a polynomial are proposed. The presented methods are based on the fixed point relation of Laguerre's type and realized in ordinary complex arithmetic as well as circular complex interval arithmetic. The derived iterative formulas are suitable for the construction of modified methods with improved convergence rate with negligible additional operations. Very fast convergence of the considered methods is illustrated by two numerical examples.
Multi-item fuzzy inventory problem with space constraint via geometric programming method
Authors: Mandal Kumar , Roy Kumar , Maiti Manoranjan
Published: November 2006

In this paper, a multi-item inventory model with space constraint is developed in both crisp and fuzzy environment. A profit maximization inventory model is proposed here to determine the optimal values of demands and order levels of a product. Selling price and unit price are assumed to be demand-dependent and holding and set-up costs sock dependent. Total profit and warehouse space are considered to be vague and imprecise. The impreciseness in the above objective and constraint goals has been expressed by fuzzy linear membership functions. The problem is then solved using modified geometric programming method. Sensitivity analysis is also presented here.
Spatial infrastructure and productivity in Sweden
Authors: Sarafoglou Nikias , Andersson Arne , Holmberg Ingvar , Ohlsson Olle
Published: November 2006

Infrastructure consists of durable resources that are classified as "collective goods" generating external effects. The purpose of this paper is to analyze the role of spatial infrastructure on the industrial productivity in Sweden by utilizing two complementary approaches: A non-parametric approach - Data Envelopment Analysis and a parametric approach - Production Function. These approaches are applied to a cross-section data set of regions in Sweden. These approaches show that metropolitan regions have relatively low road efficiencies in comparison with other regions in Sweden. On the other hand the northern regions are more efficient than the southern regions.
Organizing transportation on a double-track line under conditions of major overhaul on one track
Authors: Boskovic Branislav , Ivic Milos , Markovic Aleksandar
Published: November 2006

The problem of traffic organization on a railway line during the execution of civil works on super and sub-structures maintenance under the present conditions is becoming more and more difficult to solve, above all, due to the increased traffic intensity. In order to make decisions on indispensable measures to be taken under such circumstances, one needs information on train compositions and their delays, line capacity, facilities, etc. In order to obtain such information, it is necessary to use a computer simulation which significantly enhances the range of the problem to be solved and offers answers to the questions that cannot be solved by analytical models alone. The paper presents a simulation model of the trains? movement on a double-track line when one track is closed to traffic due to the work executions. Such model will provide a better quality of decision-making in the process of traffic organization under given circumstances.
Detection of low‐level mosaicism by array CGH in routine diagnostic specimens
Authors: Ballif Blake C. , Rorem Emily A. , Sundin Kyle , Lincicum Matt , Gaskin Shannon , Coppinger Justine , Kashork Catherine D. , Shaffer Lisa G. , Bejjani Bassem A.
Published: November 2006

The advent of microarray‐based comparative genomic hybridization (array CGH) promises to revolutionize clinical cytogenetics because of its ability to rapidly screen the genome at an unprecedented resolution. Yet, the ability of array CGH to detect and evaluate low‐level mosaicism is not known. Our laboratory has analyzed over 3,600 clinical cases with the SignatureChip® which we developed for the detection of microdeletions, microduplications, aneuploidy, unbalanced translocations, and subtelomeric and pericentromeric copy number alterations. Here, we report 18 cases of mosaicism detected by array CGH in a routine diagnostic setting, 14 of which were not known to us at the time of the analysis. These 14 cases represent ∼8% of all abnormal cases identified in our laboratory. For each case, fluorescence in situ hybridization (FISH) analysis was performed on PHA‐stimulated cultures after mosaic chromosome abnormalities were suspected by array CGH. In all cases, FISH confirmed the mosaic chromosome abnormalities which included a variety of marker chromosomes, autosomal trisomies, terminal and interstitial deletions, and derivative chromosomes. Interestingly, confirmatory FISH analyses on direct blood smears indicated that the percentage of abnormal cells in unstimulated cultures was in some cases different than that found in PHA‐stimulated cells. We also report the detection of a previously unsuspected case of an isochromosome 12p (associated with Pallister–Killian syndrome) by array CGH using genomic DNA extracted from peripheral blood. These results support a growing body of data that suggests that stimulated peripheral blood cultures likely distort the percentage of abnormal cells and may, for some chromosome abnormalities, make their detection unlikely by conventional analysis. Thus, array CGH, which is based on genomic DNA extracted directly from uncultured peripheral blood, may be more likely to detect low‐level mosaicism for unbalanced chromosome abnormalities than traditional cytogenetic techniques. © 2006 Wiley‐Liss, Inc.
Paralysis elicited by spinal cord injury evokes selective disassembly of neuromuscular synapses with and without terminal sprouting in ankle flexors of the adult rat
Authors: Burns Anthony S. , Jawaid Sabiha , Zhong Hui , Yoshihara Hiroyuki , Bhagat Srishti , Murray Marion , Roy Roland R. , Tessler Alan , Son Young‐Jin
Published: November 2006

Neuromuscular junctions (NMJs) innervated by motor neurons below spinal cord injury (SCI) have been reported to remain intact despite the interruption of supraspinal pathways and the resultant loss of activity. Here we report notably heterogeneous NMJ responses to SCI that include overt synapse disassembly. Complete transection of the thoracic spinal cord of adult rats evoked massive sprouting of nerve terminals in a subset of NMJs in ankle flexors, extensor digitorum longus, and tibialis anterior. Many of these synapses were extensively disassembled 2 weeks after spinal transection but by 2 months had reestablished synaptic organization despite continuous sprouting of their nerve terminals. In contrast, uniform and persistent loss of acetylcholine receptors (AChRs) was evident in another subset of NMJs in the same flexors, which apparently lacked terminal sprouting and largely maintained terminal arbors. Other synapses in the flexors, and almost all the synapses in the ankle extensors, medial gastrocnemius, and soleus, remained intact, with little pre‐ or postsynaptic alteration. Additional deafferentation of the transected animals did not alter the incidence or regional distribution of either type of the unstable synapses, whereas cycling exercise diminished their incidence. The muscle‐ and synapse‐specific responses of NMJs therefore reflected differential sensitivity of the NMJs to inactivity rather than to differences in residual activity. These observations demonstrate the existence of multiple subpopulations of NMJs that differ distinctly in pre‐ and postsynaptic vulnerability to the loss of activity and highlight the anatomical instability of NMJs caudal to SCI, which may influence motor deficit and recovery after SCI. J. Comp. Neurol. 500:116–133, 2007. © 2006 Wiley‐Liss, Inc.
Motor neuron degeneration in amyotrophic lateral sclerosis mutant superoxide dismutase‐1 transgenic mice: Mechanisms of mitochondriopathy and cell death
Authors: Martin Lee J. , Liu Zhiping , Chen Kevin , Price Ann C. , Pan Yan , Swaby Jason A. , Golden W. Christopher
Published: November 2006

The mechanisms of human mutant superoxide dismutase‐1 (mSOD1) toxicity to motor neurons (MNs) are unresolved. We show that MNs in G93A‐mSOD1 transgenic mice undergo slow degeneration lacking similarity to apoptosis structurally and biochemically. It is characterized by somal and mitochondrial swelling and formation of DNA single‐strand breaks prior to double‐strand breaks occurring in nuclear and mitochondrial DNA. p53 and p73 are activated in degenerating MNs, but without nuclear import. The MN death is independent of activation of caspases‐1, ‐3, and ‐8 or apoptosis‐inducing factor within MNs, with a blockade of apoptosis possibly mediated by Aven up‐regulation. MN swelling is associated with compromised Na,K‐ATPase activity and aggregation. mSOD1 mouse MNs accumulate mitochondria from the axon terminals and generate higher levels of superoxide, nitric oxide, and peroxynitrite than MNs in control mice. Nitrated and aggregated cytochrome c oxidase subunit‐I and α‐synuclein as well as nitrated SOD2 accumulate in mSOD1 mouse spinal cord. Mitochondria in mSOD1 mouse MNs accumulate NADPH diaphorase and inducible nitric oxide synthase (iNOS)‐like immunoreactivity, and iNOS gene deletion extends significantly the life span of G93A‐mSOD1 mice. Prior to MN loss, spinal interneurons degenerate. These results identify novel mechanisms for mitochondriopathy and MN degeneration in amyotrophic lateral sclerosis (ALS) mice involving blockade of apoptosis, accumulation of MN mitochondria with enhanced toxic potential from distal terminals, NOS localization in MN mitochondria and peroxynitrite damage, and early degeneration of α‐synuclein+ interneurons. The data support roles for oxidative stress, protein nitration and aggregation, and excitotoxicity as participants in the process of MN degeneration caused by mSOD1. J. Comp. Neurol. 500:20–46, 2007. © 2006 Wiley‐Liss, Inc.
Visual system of calliphorid flies: Organization of optic glomeruli and their lobula complex efferents
Authors: Strausfeld Nicholas J. , Okamura Jun‐Ya
Published: November 2006

Reconstructions of silver‐stained brains revealed 27 optic glomeruli that occupy a major volume of the lateral protocerebrum. Axons from different morphological types of columnar output neurons from the lobula complex sort out to specific glomeruli. Glomeruli are partially enwrapped by glial processes and are invaded by the dendrites and terminals of local interneurons that connect different glomeruli in a manner analogous to local interneurons in the antennal lobes. Each type of columnar neuron contributes to a palisade‐like ensemble that extends across the whole or a circumscribed area of the retinotopic mosaic. A second class of outputs from the lobula comprises wide‐field neurons, the dendrites of which interact with planar fields or column‐like patches of retinotopic inputs from the medulla. These neurons also send their axons to optic glomeruli. Dye fills demonstrate that lobula complex neurons supplying glomeruli do not generally terminate directly on descending neurons. Local interneurons and projection neurons provide integrative circuitry within and among glomeruli. As exemplified by the anterior optic tubercle, optic glomeruli can also have elaborate internal architectures. The results are discussed with respect to the identification of motion‐ and orientation‐selective neurons at the level of the lobula and lateral protocerebrum and with respect to the evolutionary implications raised by the existence of neural arrangements serving the compound eyes, which are organized like neuropils serving segmental ganglia equipped with appendages. J. Comp. Neurol. 500:166–188, 2007. © 2006 Wiley‐Liss, Inc.
Mash1 regulates the development of C cells in mouse thyroid glands
Authors: Kameda Yoko , Nishimaki Toshiyuki , Miura Masaaki , Jiang Shin‐Xu , Guillemot François
Published: November 2006

In mammals, the ultimobranchial body derived from the fourth pharyngeal pouch gives rise to thyroid C cells. The C cells of newborn mice are immunoreactive for calcitonin, calcitonin gene–related peptide (CGRP), protein gene product (PGP) 9.5 and NeuroD, and transiently exhibit the neuronal markers TuJ1 and somatostatin during fetal development. The basic helix‐loop‐helix (bHLH) transcription factor Mash1 plays a role in the differentiation of autonomic neurons. We show that in wild‐type mouse embryos, Mash1 is expressed in the ultimobranchial body at embryonic day (E) 12.5, when the body is located close to the great arch arteries. It is also expressed in the ultimobanchial body fused with the thyroid lobe at E 13.5. Targeted disruption of Mash1 resulted in the absence of C cells in the mouse thyroid glands, since cells displaying the C‐cell markers and expressing NeuroD were not detected during fetal development or at birth. The failure of C‐cell formation in the null mutant thyroids was also confirmed by electron microscopy. While the formation and migration of the ultimobranchial body were not affected in the Mash1 null mutants, at E 12.5–E 13.5 both the ultimobranchial body located close to the arteries and the organ populating the thyroid lobe exhibited a marked increase in apoptotic cell numbers. Thus, in the mutant mice, the ultimobranchial body fails to complete its differentiation program and finally dies. These results indicate that Mash1 enhances survival of the C‐cell progenitors by inhibiting apoptosis. Developmental Dynamics 236:262–270, 2007. © 2006 Wiley‐Liss, Inc.
Relationships between regulatory T cells and CD8+ effector populations in patients with squamous cell carcinoma of the head and neck
Authors: Chikamatsu Kazuaki , Sakakura Koichi , Whiteside Theresa L. , Furuya Nobuhiko
Published: November 2006

Background

Homeostasis of circulating T cells is regulated in complex ways that have not yet been well defined. The balance between type 1 and type 2 T‐cell subsets in cancer patients is thought to modulate antitumor immunity. Meanwhile, CD4+CD25+ regulatory T cells (Treg), which are potent inhibitors of antitumor immune responses, also play an invaluable role in maintaining immune homeostasis.

Methods

Peripheral blood was obtained from 42 patients with squamous cell carcinoma of the head and neck (SCCHN) and 24 healthy age‐selected donors. The percentages of T‐cell subsets and their cytokine profiles expressed in response to ex vivo stimulation were studied by multicolor flow cytometry.

Results

Although patients with SCCHN had a lower percentage (p < .05) of circulating CD4+ T cells than healthy donors, CD4+CD25+ regulatory T cells (Treg) were increased in the patients (p < .01). A significant increase in Th1 and Th2 CD4+ T cells was observed in the patients after ex vivo stimulation with phorbol 12‐myristate 13‐acetate /ionomycin. The percent of Treg inversely correlated with that of total CD8+ T cells (p < .05), CD8+IFN‐γ+ (Tc1) cells (p < .05), and CD8+IL‐4+ (Tc2) cells (p < .01). There was a highly significant correlation between Tc1 and Tc2 CD8+ T cells (p < .0001) in SCCHN patients but not in controls.

Conclusions

Treg are increased in proportion in the circulation of patients with SCCHN. These cells appear to downregulate cytokine expression in both Tc1 and Tc2 subsets of CD8+ effector T cells, which may be responsible for antitumor responses. © 2006 Wiley Periodicals, Inc. Head Neck 2007
Numerical investigation on the temperature effect on the transport of soil solute
Authors: Fan A.W. , Liu W. , Xu G.L.
Published: November 2006

In the present paper, a mathematical model called the TE‐Model has been built to describe the simultaneous transport of heat, water, gas, and solute in soil, in which the temperature effects on the transports of soil water and soil solute were taken in account. When the temperature effect was neglected, we call it the NTE‐Model. Taking NaCl as an example, numerical calculations under constant environmental factors have been carried out to investigate the temperature effect on the transport of soil solute, which showed that the concentrations of NaCl in deep soil layers rose rapidly at the initial stage and then the upward movements slowed down. However, there was a large hysteresis in the concentration variation of soil solute in the shallow layers. After the initial stage, the concentration of NaCl rose almost linearly with time. Furthermore, the concentrations calculated through the TE‐Model was larger than those calculated through the NTE‐Model. At the conclusion of the 5‐year calculating process, relative deviations in soil solute concentration at 10 different depths have been found to reach 61.5%, 59.6%, 54.7%, 49.2%, 44.5%, 40.9%, 37.5%, 34.1%, 29.8%, and 23.0%, respectively. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(8): 539–552, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20137
Electronic structure and bonding studies on triple‐decker sandwich complexes with a P6 middle ring
Authors: Rani Dandamudi Usha , Prasad Dasari L. V. K. , Nixon John F. , Jemmis Eluvathingal D.
Published: November 2006

DFT and hybrid HF‐DFT studies of structure and bonding of CpMP6MCp triple‐decker sandwich complexes, ranging from 18–28 valence electrons (VE) with M = Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, show that the middle P6 ring complexes adopt symmetric planar (28 valence electron count [VEC]), asymmetric planar (26 VEC), and puckered (24 VEC) geometries. According to the mno Rule, 50 skeletal electrons are needed for these triple‐decker cluster frameworks. For 28 VEC, this corresponds to 10 electrons more than the 50 electrons of the mno Rule if all VE of the metal are included. These additional electrons control the distortion of a P6 middle ring and other finer structural details. Completely filled 2a* and 2b* orbitals in 28 VE complexes lead to a planar symmetrical P6 middle ring, while the occupancy in either 2a* or 2b* alone explains the in‐plane distortions (asymmetric) in 26 VE complexes. In comparison with 28 VE complexes, the puckering of P6 middle ring in 24 VE complexes is due to the greater stabilization of 5a and the extra stabilization of the +4 oxidation state of Ti. The quintet state of 22 VE complexes is planar as 2a* and 2b* are half filled. Similar geometrical and bonding patterns of CpScP6ScCp and C2P3H2ScC3P3H3ScC2P3H2 support the carbon–phosphorus analogy further. The 18 VE systems, CpScC3B3H6ScCp+ and CpScP3B3H3ScCp+, have the 50 skeletal electrons as stipulated by the mno Rule. Corresponding anions have 52 skeletal electrons (20 VE); the middle rings here are distorted in the plane. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2007
Influence of plant matrix on microwave‐assisted extraction process. The case of diosgenin extracted from fenugreek (Trigonella foenum‐graecum L.)
Authors: Kaufmann Béatrice , Rudaz Serge , Cherkaoui Samir , Veuthey Jean‐Luc , Christen Philippe
Published: November 2006

A focused microwave‐assisted extraction method was developed for the extraction of diosgenin from fenugreek (Trigonella foenum‐graecum) seeds, air‐dried and fresh leaves and air‐dried roots. Several experimental parameters were studied, including extraction time, microwave power applied and percentage of 2‐propanol in the extraction mixture as well as their interactions, in order to optimize the extraction efficiency. The two latter parameters were found to be the most important. Response surface modelling was used to predict the extraction yield of diosgenin in selected matrices. The analysis of diosgenin in crude extracts was carried out by capillary gas chromatography–mass spectrometry (GC‐MS). Copyright © 2006 John Wiley & Sons, Ltd.
Supramolecular aggregations through the inclusion complexation of cyclodextrins and polymers with bulky end groups
Authors: Chan Shih‐Chi , Kuo Shiao‐Wei , She Hwo‐Shuenn , Lin Ho‐May , Lee Hsin‐Fang , Chang Feng‐Chih
Published: November 2006

Mono‐polyhedral oligomeric sillsesquioxane‐end capped poly(ε‐caprolactone) (mPPCL) can form inclusion complexes (ICs) with α‐ and γ‐cyclodextrins (CDs) but not with β‐CD. These CD ICs have been characterized with X‐ray diffraction, solid‐state 13C cross‐polarization/magic‐angle‐spinning NMR spectroscopy, 1H NMR spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. The poly(ε‐caprolactone) (PCL) chain of mPPCL is included within the channel provided by the CDs to form a columnar, crystalline structure. The PCL/CD ratios determined by 1H NMR spectroscopy for the ICs with α‐ or γ‐CDs are higher than the stoichiometries because of the steric hindrance of the bulky polyhedral oligomeric silsesquioxane chain end and result in a fraction of the ε‐caprolactone units free from complexation with the CDs. On the basis of these analyses, we propose some possible structures for these CD/mPPCL ICs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 125–135, 2007
Effect of palm oil carotene on breat cancer tumorigenicity in nude mice
Authors: Nesaretnam Kalanithi , Radhakrishnan Ammu , Selvaduray Kanga Rani , Reimann Karin , Pailoor Jayalakshmi , Razak Ghazali , Mahmood Mina Mustafa , Dahliwal Jasbir Singh
Published: November 2006

Biological therapies are new additions to breast cancer treatment. Among biological compounds, β‐carotene has been reported to have immune modulatory effects, in particular, enhancement of natural killer cell activity and tumor necrosis factor‐alpha production by macrophages. The objective of this study was to investigate the effect of palm carotene supplementation on the tumorigenicity of MCF‐7 human breast cancer cells injected into athymic nude mice and to explore the mechanism by which palm carotenes suppress tumorigenesis. Forty‐eight 4‐wk‐old mice were injected with 1×106 MCF‐7 cells into their mammary fat pad. The experimental group was supplemented with palm carotene whereas the control group was not. Significant differences were observed in tumor incidence (P<0.001) and tumor surface area and metastasis to lung (P<0.005) between the two groups. Natural killer (NK) cells and B‐lymphocytes in the peripheral blood of carotene‐supplemented mice were significantly increased (P<0.05 and P<0.001, respectively) compared with controls. These results suggest that palm oil carotene is able to modulate the immune system by increasing peripheral blood NK cells and B‐lymphocytes and suppress the growth of MCF‐7 human breast cancer cells.
Transfer of lipids between hemolymph and hepatopancreas in the shrimp Macrobrachium borellii
Authors: García Fernando , González‐Baró María , Pollero Ricardo
Published: November 2006

Crustancean lipids are transported in the hemolymph by an HDL. The hepatopancreas is the most important and active organ regarding lipid metabolism, so we studied the interchange of FA and acylglycerols between both components of the hepatopancreas‐hemolymph system in the decapod crustacean Macrobrachium borellii. The hepatopancreas and a sole plasma lipoprotein were labeled by in vivo incubations with 14C palmitic acid injected into the hemolymph. Then they were incubated in vitro with unlabeled hepatopancreas and hemolymph, and the transfer of lipids between them was measured by radiochromatographic techniques. It was determined in vivo that more than 80% of the circulating palmitic acid was taken up by the hepatopancreas and incorporated into PC and TAG. Both classes of lipids, but mainly PC, were transferred back from tissues to the hemolymph. Lipid transfer was also demonstrated in vitro. The transfer of PC (30% of labeling) as well as that of FFA (48% of labeling) from hemolymph to hepatopancreas was determined. On the other hand, FFA were released more efficiently than the acylglycerols from intact hepatopancreas to hemolymph, and they were the only lipid transferred when the hepatopancreas had been previously washed.
Effects of dietary conjugated linoleic acid on the expression of uncoupling proteins in mice and rats
Authors: Ealey Kafi N. , El‐Sohemy Ahmed , Archer Michael C.
Published: November 2006

CLA inhibits mammary cancer and reduces body fat accumulation in rodents. It is not known whether uncoupling proteins (UCP), which are modulators of energy balance and metabolism, play a role in these actions of CLA. To determine the effects of dietary CLA on the expression of UCP in various tissues, 5‐wk‐old Sprague‐Dawley rats and C57BI/6 mice were fed diets containing 1% CLA for 3 wk. CLA treatment reduced adipose depot weights in both rats and mice but had no significant effects on body weight. There was a species‐specific effect of CLA on the expression of UCP. Whereas CLA did not affect the expression of UCP in most tissues in rats, mice fed CLA had increased expression of UCP2 in the mammary gland, brown adipose tissue (BAT), and white adipose tissue (WAT). Furthermore, UCP1 and UCP3 mRNA and protein levels in BAT were significantly lower in CLA‐fed mice compared to controls. Skeletal muscle UCP3 mRNA was unchanged, but UCP3 protein levels were significantly increased in mice, suggesting translational or posttranslational regulation of this protein. Results from this study suggest that alterations in the expression of UCP in mice may be related to the previously reported effects of dietary CLA in lowering adiposity and increasing FA oxidation. In rats, however, induction of UCP is not likely to be responsible for fat reduction or for the inhibitory action of CLA on mammary carcinogenesis.
Lipids and Δ6‐desaturase activity alterations in rat liver microsomal membranes induced by fumonisin B1
Authors: Gelderblom W. C. A. , Moritz W. , Swanevelder S. , Smuts C. M. , Abel S.
Published: November 2006

Alterations in the membrane structure and function of hepatocyte membranes by fumonisin B1 (FB1) have been proposed to play an important role in the disruption of growth regulatory effects and hence in the cancer‐promoting ability of the mycotoxin. Detailed analyses of lipids in liver microsomal fractions of rats exposed to different dietary levels of FB1 over a period of 21 d indicated an increase in PC, PE, PI, and cholesterol (Chol). These changes decreased the PC/PE and increased the total phospholipid/Chol ratios. When considering FA content, the quantities of total FA increased (P<0.05) in the major phospholipid fractions as a result of the increased phospholipid levels. However, when considering the relative levels (mg/100 mg of the total FA) of specific FA, the monounsaturated FA (16∶1n−7 and 18∶1n−9) and 18∶2n−6 increased (P<0.05), whereas the long‐chain PUFA decreased (P<0.05) in the main phospholipid fractions. Enzyme analyses indicated that the activity of the Δ6‐desaturase was significantly reduced in liver microsomal preparations in a dose‐dependent manner. An increase in the 20∶3n−6/20∶4n−6 ratio also suggested a decrease in the activity of the Δ5‐desaturase. Disruption of microsomal lipid metabolism at different levels by FB1 could play an important role in the alteration of growth regulatory effects in the liver.
Destabilizing effects of fructose‐1,6‐bisphosphate on membrane bilayers
Authors: Ehringer William D. , Su Susan , Chiang Benjamin , Stillwell William , Chien Sufan
Published: November 2006

Fructose‐1,6‐bisphosphate (FBP) is a high‐energy glycolytic intermediate that decreases the effects of ischemia; it has been used successfully in organ perfusion and preservation. How the cells utilize external FBP to increase energy production and the mechanism by which the molecule crosses the membrane bilayer are unclear. This study examined the effects of FBP on membrane bilayer permeability, membrane fluidity, phospholipid packing, and membrane potential to determine how FBP crosses the membrane bilayer. Large unilamellar vesicles composed of egg phosphatidylcholine (Egg PC) were made and incubated with 50 mM FBP spiked with 14C‐FBP at 30°C. Uptake of FBP was significant (P<0.05) and dependent on the lipid concentration, suggesting that FBP affects membrane, bilayer permeability. With added calcium (10 mM), FBP uptake by lipid vesicles decreased significantly (P<0.05). Addition of either 5 or 50 mM FBP led to a significant increase (P<0.05) in Egg PC carboxyfluorescein leakage. We hypothesized that the membrane‐permeabilizing effects of FBP may be due to a destabilization of the membrane bilayer. Small unilamellar vesicles composed of dipalmitoyl pC (DPPC) were made containing either diphenyl‐1,3,5‐hexatriene (DPH) or trimethylammmonia‐DPH (TMA‐DPH) and the effects of FBP on the fluorescence anisotropy (FA) of the fluorescent labels examined. FBP caused a significant decrease in the FA of DPH in the liquid crystalline state of DPPC (P<0.05), had no effect on FA of TMA‐DPH in the liquid crystalline state of DPPC, but increased the FA of TMA‐DPH in the gel state of DPPC. From phase transition measurements with DPPC/DPH or TMA‐DPH, we calculated the slope of the phase transition as an indicator of the cooperativity of the DPPC molecules. FBP significantly decreased the slope, suggesting a decrease in fatty acyl chain interaction (P<0.05). The addition of 50 mM FBP caused a significant decrease (P<0.05) in the liquid crystalline/gel state fluorescence ratio of merocyanine 540, indicating increased head‐group packing. To determine what effects these changes would have on cellular membranes, we labeled human endothelial cells with the membrane potential probe 3,3′‐dipropylthiacarbocyanine iodide (DiSC3) and then added FBP. FBP caused a significant, dose‐dependent decrease in DiSC3 fluorescence, indicating membrane depolarization. We suggest that FBP destabilizes membrane bilayers by decreasing fatty acyl chain interaction, leading to significant increases in membrane permeability that allow FBP to diffuse into the cell where it can be used as a glycolytic intermediate.
Simultaneous determination by GC‐MS of epoxy and hydroxy FA as their methoxy derivatives
Authors: Wilson R. , Lyall K.
Published: November 2006

We report on a capillary GC‐MS method for the quantitative analysis of hydroxy and epoxy FA. Catalytic hydrogenation of lipid extracts produces stable saturated lipids. Saponification followed by methylation with boron trifluoride in the presence of methanol converts FA to methyl esters and epoxy groups to methoxy‐hydroxy groups. These compounds are purified from nonoxidized methyl esters using solid phase extraction. Derivatization of the hydroxy group using tetramethylammonium hydroxide forms methoxy and vicinal dimethoxy FAME. When subjected to El‐MS, fragmentation gives two characteristic ion fragments for each epoxy and hydroxy positional isomer. Quantitative measurements were achieved using uniformly labeled hydroxy and epoxy 13C FA as internal standards. Epoxy and hydroxy FA were identified in both plasma and adipose tissue of men, and the levels of hydroxy and epoxy in these tissues were related. The levels of hydroxy isomers were typical of oxidation of linoleic acid, whereas epoxy isomers were characteristic of oxidation of oleic acid.
Apolipoproteins A‐I and A‐II downregulate neutrophil functions
Authors: Furlaneto Cristiane Jaciara , Ribeiro Fernanda Pereira , Hatanaka Elaine , Souza Glaucia Mendes , Cassatella Marco A. , Campa Ana
Published: November 2006

This work reports the effect of the apolipoproteins A‐I and A‐II (apoA‐I and apoA‐II) on the release of tumor necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐8, and IL‐1 receptor antagonist (IL‐1Ra) and on the oxidative burst of human neutrophils. By themselves, apoA‐I and apoA‐II do not affect the basal liberation of these cytokines, whereas apoA‐I affects the release of IL‐1β from lipopolysaccharide (LPS)‐stimulated neutrophils and apoA‐II affects IL‐8 released from LPS‐stimulated neutrophils. ApoA‐II also decreases the production of IL‐8 released by neutrophils stimulated with the acute phase apolipoprotein serum amyloid A. Both apoA‐I and apoA‐II exerted ∼30% inhibition on the oxidative burst of neutrophils stimulated by opsonized zymosan, as revealed by the luminol‐enhanced chemiluminescence assay. These findings give additional support to the idea that the role of human plasma lipoproteins and apolipoproteins goes beyond their function in lipid transport and metabolism. HDL apolipoproteins appear to be a class of mediators that can participate in the regulation of the activity of neutrophils.
Purification of lipoxygenase from Chlorella: Production of 9‐ and 13‐hydroperoxide derivatives of linoleic acid
Authors: Nuñez Alberto , Savary Brett J. , Foglia Thomas A. , Piazza George J.
Published: November 2006

Oxygenation of linoleic acid by the enzyme lipoxygenase (LOX) that is present in the microalga Chlorella pyrenoidosa is known to produce the corresponding 9‐and 13‐hydroperoxide derivatives of linoleic acid (9‐ and 13‐HPOD, respectively). Previous work with this microalga indicated that partially purified LOX, present in the 30–45 and 45–80% saturated (NH4)2SO4 precipitate fractions, produced both HPOD isomers but in different ratios. It was not clear, however, if the observed activity in the two isolates represented the presence of one or more isozymes. In the present work, LOX isolated from the intracellular fraction of Chlorella by (NH4)2SO4 precipitation (35–80% saturated) was purified by ion exchange and hydrophobic interaction chromatography to apparent homogeneity. Analysis of the purified protein by SDS‐PAGE and subsequent native size exclusion chromatography demonstrated that LOX in Chlorilla is a single monomeric protein with a molecular mass of approximately 47 kDa. The purified LOX produced both the 9‐HPOD and 13‐HPOD isomers from linoleic acid in equal amounts, and the isomer ratio was not altered over the pH range of 6 to 9. Optimal activity of LOX was at pH 7.5.
Olive oil phenolics protect LDL and spare vitamin E in the hamster
Authors: Wiseman Sheila A. , Tijburg Lilian B. M. , van de Put Frans H. M. M.
Published: November 2006

An animal feeding trial was conducted to investigate whether olive oil phenolics can act as functional antioxidants in vivo. To this end, hamsters were exposed for a period of 5 wk to a dietary regime with either a phenol‐rich extra virgin olive oil or extra virgin olive oil from which phenols were removed by ethanol/water‐washing. The original oil used in the high olive phenol diet was also used for the preparation of the low phenol diet in order to keep the FA compositions exactly the same. In addition, the vitamin E content was kept identical in both diets. This careful preparation of the diets was undertaken in order to prevent these factors from influencing the antioxidative status in plasma and LDL. Removal of olive oil phenols was shown to reduce both the vitamin E level in plasma and the resistance of LDL to ex vivo oxidation. The results of this study support the idea that extra virgin olive oil phenols improve the antioxidant defense system in plasma by sparing the consumption of vitamin E under normal physiological circumstances.
FA composition of cholesteryl esters and phospholipids in maternal plasma during pregnancy and at delivery and in cord plasma at birth
Authors: De Vriese S. R. , Dhont M. , Christophe A. B.
Published: November 2006

The purpose of this study was to assess the FA composition of both cholesteryl esters (CE) and phospholipids (PL) in maternal plasma during pregnancy and at delivery and in umbilical plasma at birth. A longitudinal study of 32 normal pregnant women was carried out with three cutoff points during pregnancy (first, second, and third trimester) and at delivery. Few significant differences occurred in the FA profile of maternal CE: 18∶1n−9 increased, 18∶2n−6 dropped slightly, and 18∶3n−3 decreased with progressing gestation. In maternal PL, long‐chain highly unsaturated FA concentrations dropped and were replaced by saturated FA as gestation progressed. Additionally, changes in saturated FA in PL occurred: Shorter‐chain 16∶0 was higher whereas longer‐chain 18∶0 was lower at delivery compared to early pregnancy. The FA profile of umbilical venous plasma was strikingly different from that of maternal plasma at delivery. Cord plasma CE contained more saturated and monounsaturated FA than maternal CE. The polyunsaturates 18∶2n−6 and 18∶3n−3 are lower in umbilical CE than in maternal CE whereas 20∶4n−6 and 22∶6n−3 are twice as high in umbilical CE. Cord plasma PL have a higher content of long‐chain highly unsaturated FA than maternal plasma PL at delivery. In contrast to maternal plasma PL, 16∶0 was lower and longer‐chain saturated FA were higher in cord plasma PL. The FA profile of umbilical plasma at birth shows preferential accumulation of 20∶4n−6 and 22∶6n−3, with low concentrations of 18∶2n−6 and 18∶3n−3 in CE and PL, indicating a preferential supply of the fetus with long‐chain highly unsaturated FA needed for fetal development.
Acute elevations of medium‐and long‐chain fatty acids have different impacts on endothelium‐dependent vasodilation in humans
Authors: Steer Peter , Basu Samar , Lithell Hans , Vessby Bengt , Berne Christian , Lind Lars
Published: November 2006

It has previously been shown that acute elevation of long‐chain fatty acids (LCFA) impairs endothelium‐dependent vasodilation (EDV) in humans. In this study, we tested the hypothesis that an elevation of both medium‐chain fatty acids (MCFA) and LCFA affects the endothelium differently from LCFA elevation alone. Ten healthy volunteers received an intravenous infusion of Structolipid≿ (structured TG, MCFA/LCFA ratio 1∶1) and heparin for 2 h, while another 10 subjects received an infusion of Intralipid≿ (LCFA only) and heparin. EDV and endothelium‐independent vasodilation (EIDV) were studied in the forearm after local administration of methacholine chloride (2 and 4 μg/min) and sodium nitroprusside (5 and 10 μg/min). Forearm blood flow was determined by venous occlusion plethysmography. Intralipid and heparin increased circulating FA levels from 0.2±0.1 to 1.4±0.5 mmol/L (P<0.001) and reduced EDV by 20% (P<0.01). Although Structolipid and heparin increased circulating FA levels to a similar extent (from 0.4±0.1 to 1.8±0.4 mmol/L after 2 h), EDV was not significantly changed. EIDV increased slightly during both interventions (P<0.05). In conclusion, an acute elevation of LCFA attenuated EDV, whereas an elevation of both MCFA and LCFA did not influence EDV. Thus, FA composition seems to be of importance for EDV in healthy humans.
Very long chain PUFA in murine testicular triglycerides and cholesterol esters
Authors: Furland Natalia E. , Maldonado Eduardo N. , Aveldaño Marta I.
Published: November 2006

Very long chain (VLC) PUFA of the n−6 and n−3 series are known to occur in mammalian testis. The aim of this work was to characterize further two testicular lipid classes with VLCPUFA, cholesterol esters (CE) and total triglycerides (TG) in rat and mouse testis. The VLCPUFA predominating in these lipids were a series of n−6 pentaenes and tetraenes with 24 to 32 carbons, including small amounts of odd‐chain PUFA, 28∶5n−6 and 24∶5n−6 prevailing in CE and TG, respectively. Most of the VLCPUFA of TG were concentrated in a small fraction of TG, made up by 1‐O‐alkyl‐2,3‐DAG. This TG subclass was absent altogether from the TG of sexually immature testis. The TG and the CE with VLCPUFA only occurred in testis of adult fertile animals. The proportion of VLCPUFA in total TG and CE was higher in rodents than in other mammals. In the n−6 PUFA‐rich adult mouse testis, the amounts of testicular triacylglycerols decreased significantly after consumption of fish oil for 2 wk. Whereas 18∶2n−6 was significantly reduced, the amounts of 22∶5n−6 and longer n−6 PUFA were less affected in all mamor testicular lipids including PC and PE, where they were unchanged. The 1‐O‐alkyl‐2,3‐DAG and their n−6 VLCPUFA were virtually unaffected by the diet. The VLCPUFA‐containing molecular species of CE and TG may represent a form of storage of cholesterol and polyenoic FA required to sustain spermatogenesis. Via chain‐shortening, VLCPUFA stored in the neutral lipids may serve as precursors of the major C22 PUFA typical of cell membrane glycerophospholipids, protecting testicular cells against shifts in FA composition induced by dietary changes.
Phospholipid FA from indian ocean tunicates Eudistoma bituminis and Cystodytes violatinctus
Authors: Viracaoundin I. , Barnathan G. , Gaydou E. M. , Aknin M.
Published: November 2006

Two tunicates (Fudistoma bituminis and Cystodytes violatinctus, family Polycitoridae) were investigated for the FA content of their phospholipids. GC‐MS analysis of their methyl esters and N‐acyl pyrrolidides revealed 40 FA in E. bituminis, and 26 in C. violatinctus. In both cases, the most abundant FA were the saturated ones (C10 to C18). Cystodytes violatinctus contained considerable oleic acid (20%). Both E. bituminis and C. violatinctus contained phytanic acid and Δ10‐unsaturated FA, which had not previously been found in such organisms. The two tropical tunicates contained only trace amounts of PUFA, which are usually predominant in this phylum.
Cloning of an alkaline lipase gene from Penicillium cyclopium and its expression in Escherichia coli
Authors: Wu Minchen , Qian Zhikang , Jiang Peihong , Min Taishan , Sun Chongrong , Huang Weida
Published: November 2006

The gene encoding an alkaline lipase of Penicillium cyclopium PG37 was cloned with four steps of PCR amplification based on different principles. The cloned gene was 1,480 nucleotides in length, consisted of 94 bp of promoter region, and had 6 exons and 5 short introns ranging from 50 to 70 nucleotides. The open reading frame encoded a protein of 285 amino acid residues consisting of a 27‐AA signal peptide and a 258‐AA mature peptide, with a conserved motif of Gly‐X‐Ser‐X‐Gly shared by all types of alkaline lipases. However, this protein had a low homology with lipases of P. camembertii (22.9%), Humicola lanuginosa (25.6%), and Rhizomucor miehei (22.3%) at the amino acid level. The mature peptide‐encoding cDNA was cloned and expressed in Escherichia coli on pET‐30a for confirmation. A distinct band with a M.W. of 33 kDa was detected on SDS‐PAGE. Results of a Western blot analysis and an enzyme activity assay verified the recombinant 33‐kDa protein as an alkaline lipase. Its catalytic properties were not changed when compared with its natural counterpart.
Antioxidant action of a lipophilic nitroxyl radical, cyclohexane‐1‐spiro‐2′‐(4′‐oxyimidazolidine‐1′‐oxyl)‐5′‐spiro‐1″‐cyclohexane, against lipid peroxidation under hypoxic conditions
Authors: Shimakawa Shuichi , Yoshida Yasukazu , Niki Etsuo
Published: November 2006

Nitroxyl radicals are known to act as radical scavenging antioxidants. In the present study, a lipophilic nitroxyl radical, cyclohexane‐1‐spiro‐2′‐(4′‐oxyimidazolidine‐1′‐oxyl)‐5′‐spiro‐1″‐cyclohexane (nitroxyl radical I) was synthesized and its antioxidant capacity was assessed in comparison with a hydrophilic nitroxyl radical, 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl (Tempol). Both nitroxyl radical I and Tempol inhibited methyl linoleate oxidation induced by free radicals, and the efficacy increased with decreasing partial pressure of oxygen, the effect being more pronounced for nitroxyl radical I than Tempol. Their hydroxylamines inhibited lipid peroxidation more effectively than their corresponding parent nitroxyl radicals. In liposomal membranes, a synergistic effect was observed in the combination of nitroxyl radical I with ascorbic acid, whereas only an additive effect was observed between Tempol and ascorbic acid. The present study suggests that nitroxyl radical I and its hydroxylamine may act as potent antioxidants, especially in combination with ascorbic acid under hypoxic conditions.