bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of silenced transgene expression in neural precursor cell lines by inhibitors of histone deacetylation
Authors: Rosenqvist Nina , Hård af Segerstad Caroline , Samuelsson Christofer , Johansen Jens , Lundberg Cecilia
Published: October 2002

Background

Ex vivo gene therapy in the central nervous system (CNS) holds great promise for diseases such as the neurodegenerative disorders. However, achieving stable, long‐term transgene expression in grafted cells has proven problematic. This study reports the establishment of an in vitro model of transgene down‐regulation in cells grafted to the CNS using the immortalized neural progenitor cell lines HiB5 and RN33B.

Methods

Neural cell lines were transduced at 33°C with different GFP constructs, both viral and non‐viral, containing either viral or non‐viral promoters. Cell differentiation in vitro was obtained by culturing the cells at 37°C in serum‐free defined media, which halts cell division, and GFP‐expression was analysed by FACS. As early as day 3 of culture at 37°C, the transgene expression decreased markedly in most cell lines. To validate the assay, the same clones were grafted to the adult rat striatum and the down‐regulation of GFP‐expression was evaluated.

Results

The temporal pattern of down‐regulation was found to be similar in vitro and in vivo. Using this assay, it was shown that addition of inhibitors of histone deacetylation, but not an inhibitor of DNA methylation, reversed the silencing of GFP in quiescent neural progenitors by up to 308% of control values.

Conclusion

These results suggest that the same mechanisms controlling gene transcription of the host cell's genome are active in controlling transgene expression and that this should be taken into account when constructing vectors for gene therapy. The assay reported in this study could be used as a screening method to evaluate new vectors. Copyright © 2002 John Wiley & Sons, Ltd.
Somatic gene transfer into the lactating ovine mammary gland
Authors: Düchler Markus , Pengg Margret , Schüller Susanne , Pfneisl Franz , Bugingo Christoph , Brem Gottfried , Wagner Ernst , Schellander Karl , Müller Mathias
Published: October 2002

Background

Somatic gene therapy requires safe and efficient techniques for the gene transfer procedure. The ovine mammary gland is described as a model system for the evaluation of somatic gene transfer methods.

Methods

Different gene delivery formulations were retrogradely injected into the mammary gland of lactating sheep. The efficiency of the gene transfer was subsequently measured by the detection of the secreted transgene products in the milk. To counteract the milk flow in the lactating gland caused by the permanent milk production, a newly developed pretreatment of the mammary gland with hyperosmotic solutions was applied. In addition, in vivo electroporation of DNA into the mammary gland is described.

Results

Gene transfer using naked DNA or simple complexes of DNA with polycations did not result in traceable amounts of reporter gene products. However, utilizing the complex cationic lipid DOSPER, a peak expression of about 400 ng/ml was observed 6 days after transfection. Maximum expression rates of more than 1 µg/ml were obtained by combining hyperosmotic pretreatment and receptor‐mediated gene transfer. For the in vivo electroporation, the proof of principle for this technique in the mammary gland is reported.

Conclusions

The ovine mammary gland turned out to be a very well suited as a model system for evaluation and optimization of various gene transfer protocols. Copyright © 2002 John Wiley & Sons, Ltd.
Intracellular processing and stability of DNA complexed with histidylated polylysine conjugates
Authors: Gonçalves Christine , Pichon Chantal , Guérin Brigitte , Midoux Patrick
Published: October 2002

Background

Glycosylated polylysines and histidylated polylysines complexed with plasmid DNA (pDNA) were proposed to develop polymer‐based gene delivery systems. The present work has been undertaken in two steps to study the uptake and the intracellular processing of pDNA, which are still poorly understood in the polyfection pathway.

Methods and results

The kinetics of the uptake and the intracellular processing of pDNA complexed with lactosylated polylysine, histidylated polylysine or histidylated polylysine bearing lactosyl residues (polyplexes) into a CF human airway epithelial cell line were assessed by flow cytometry and confocal microscopy. Complexes formed from histidylated polylysine, even though they were less taken up by cells, show better transfection efficiency with compared with lactosylated complexes. Lactosylated polymers segregated more rapidly when compared with non‐lactosylated polymers into compartments different from those containing pDNA on internalization. Intracellular location and pH measurements indicated that polymers ended up in compartments of pH ∼6.2 while pDNA reached less acidic compartments of pH ∼6.6. These compartments did not contain the LAMP‐1 lysosomal marker.

Conclusions

The present study exhibits that, upon internalization, pDNA and polylysine conjugates underwent segregation with a rate depending on the polylysine substitution and polymer degradation. The better transfection efficiency of polyplexes with histidylated polylysine can be ascribed to their prolonged stability inside the endocytic vesicles that likely favored the pDNA escape in the cytosol. Copyright © 2002 John Wiley & Sons, Ltd.
Interactive body magnetic resonance fluoroscopy using modified single‐shot half‐Fourier rapid acquisition with relaxation enhancement (RARE) with multiparameter control
Authors: Makki Malek , Graves M.J. , Lomas D.J.
Published: October 2002

Purpose

To develop a technique for interactive fluoroscopic abdominal magnetic resonance imaging (MRI) based on a single‐shot half‐Fourier rapid acquisition and relaxation‐enhanced sequence.

Materials and Methods

The sequence was modified by incorporating inner‐volume excitation, driven‐equilibrium signal enhancement, and reduced flip angle refocusing pulses. Contrast control was provided by integrating “on‐the‐fly” selection of phase encoding view order, fat suppression, and section thickness. The resulting sequence was evaluated with phantom experiments to quantify the signal‐to‐noise ratio (SNR) effects of the modifications and in healthy volunteers for imaging the bile ducts, stomach, and duodenum using water and gaseous contrast media.

Results

Observed SNR relating to driven‐equilibrium and flip angle scaling matched theoretical predictions. Volunteer examinations demonstrated the ability of the modified sequence to provide interactive, artifact‐free imaging of the abdomen, including switching between conventional proton density‐weighted, T2‐weighted imaging and “hydrographic” projection imaging.

Conclusion

Refinement of this technique may provide an abdomino‐pelvic imaging capability similar in concept to real‐time ultrasound, but with the advantages of MRI. J. Magn. Reson. Imaging 2002;16:85–93. © 2002 Wiley‐Liss, Inc.
Applications of neural network analyses to in vivo 1H magnetic resonance spectroscopy of Parkinson disease patients
Authors: Axelson David , Bakken Inger Johanne , Susann Gribbestad Ingrid , Ehrnholm Benny , Nilsen Gunnar , Aasly Jan
Published: October 2002

Purpose

To apply neural network analyses to in vivo magnetic resonance spectra of controls and Parkinson disease (PD) patients for the purpose of classification.

Materials and Methods

Ninety‐seven in vivo proton magnetic resonance spectra of the basal ganglia were recorded from 31 patients with (PD) and 14 age‐matched healthy volunteers on a 1.5‐T imager. The PD patients were grouped as follows: probable PD (N = 15), possible PD (N = 11), and atypical PD (N = 5). Total acquisition times of approximately five minutes were achieved with a TE (echo time) of 135 msec, a TR (repetition time) of 2000 msec, and 128 scan averages. Neural network (back propagation, Kohonen, probabilistic, and radial basis function) and related (generative topographic mapping) data analyses were performed.

Results

Conventional data analysis showed no statistically significant differences in metabolite ratios based on measuring signal intensities. The trained networks could distinguish control from PD with considerable accuracy (true positive fraction 0.971, true negative fraction 0.933). When four classes were defined, approximately 88% of the predictions were correct. The multivariate analysis indicated metabolic changes in the basal ganglia in PD.

Conclusion

A variety of neural network and related approaches can be successfully applied to both qualitative visualization and classification of in vivo spectra of PD patients. J. Magn. Reson. Imaging 2002;16:13–20. © 2002 Wiley ‐Liss, Inc.
A method for the direct electrical stimulation of the auditory system in deaf subjects: A functional magnetic resonance imaging study
Authors: Alwatban Adnan Z. , Ludman Catherine N. , Mason Steve M. , O'Donoghue Gerard M. , Peters Andrew M. , Morris Peter G.
Published: October 2002

Purpose

To develop a safe functional magnetic resonance imaging (fMRI) procedure for auditory assessment of deaf subjects.

Materials and Methods

A gold‐plated tungsten electrode has been developed which has zero magnetic susceptibility. Used with carbon leads and a carbon reference pad, it enables safe, distortion‐free fMRI studies of deaf subjects following direct electrical stimulation of the acoustic nerve. Minor pickup of the radio frequency (RF) pulses by the electrode assembly is difficult to eliminate, and a SPARSE acquisition sequence is used to avoid any effects of unintentional auditory nerve stimulation.

Results

The procedure is demonstrated in a deaf volunteer. Activation is observed in the contralateral but not the ipsilateral primary auditory cortex. This is in sharp contrast to studies of auditory processing in hearing subjects, but consistent with the small number of previous positron emission tomography (PET) and MR studies on adult deaf subjects.

Conclusion

The fMRI procedure is able to demonstrate whether the auditory pathway is fully intact, and may provide a useful method for preoperative assessment of candidates for cochlear implantation. J. Magn. Reson. Imaging 2002;16:6–12. © 2002 Wiley‐Liss, Inc.
Passive catheter tracking using MRI: Comparison of conventional and magnetization‐prepared FLASH
Authors: Green Jordin D. , Omary Reed A. , Finn J. Paul , Tang Richard , Li Yongzhong , Carr James , Li Debiao
Published: October 2002

Purpose

To compare a magnetization‐prepared gradient‐echo (GRE) sequence with a conventional GRE sequence for visualizing contrast agent‐filled catheters.

Materials and Methods

Passive visualization of endovascular catheters using MRI was compared between two imaging sequences: 1) inversion recovery (IR)‐fast low angle shot (FLASH), and 2) conventional FLASH. Two‐dimensional projection images of the catheters filled with 4% diluted contrast agent in a phantom and the aorta of swine were obtained with each sequence with a temporal resolution of two frames per second. We compared background suppression and catheter visibility using the catheter‐to‐background signal ratio and the ratings of two radiologists.

Results

In the phantom, IR‐FLASH allowed for a 200% increase in catheter‐to‐background ratio (p < 0.01) and improved depiction of catheters over conventional FLASH. In swine, the IR‐FLASH images showed a statistically significant improvement of 80% (p < 0.001) over conventional FLASH in all comparisons of the catheter‐to‐background signal ratio, and an improvement of 160% (p < 0.05) in comparison with the radiologists' observations.

Conclusion

This study shows that IR‐FLASH is a better technique for passive tracking of contrast agent‐filled catheters than conventional FLASH. J. Magn. Reson. Imaging 2002;16:104–109. © 2002 Wiley‐Liss, Inc.
Optimal post‐contrast timing of breast MR image acquisition for architectural feature analysis
Authors: Nunes Linda White , Englander Sarah A. , Charafeddine Riad , Schnall Mitchell D.
Published: October 2002

Purpose

To define a post‐contrast imaging time span during which diagnostic accuracy of breast magnetic resonance (MR) architectural feature analysis is maintained.

Materials and Methods

Seventy‐five patients with mammographically‐visible or palpable findings underwent MR examination. Three sequential post‐contrast, fat‐saturated, three‐dimensional gradient‐echo imaging runs were acquired spanning 0–90, 90–180, and 180–270 seconds after contrast injection. Five readers independently predicted the malignant potential of the MR abnormalities.

Results

Receiver‐operator characteristics (ROC) curves were our primary measure of diagnostic accuracy. The accuracy of four readers was unchanged over the three post‐contrast runs. One reader was slightly more accurate using the second and third runs than using the first.

Conclusion

For most readers, a single post‐contrast run performed at any point during the first four minutes and 30 seconds following injection should yield an equivalent diagnostic accuracy. If any time period is less optimal, it is that of our first run, performed between 0–90 seconds after contrast injection. J. Magn. Reson. Imaging 2002;16:42–50. © 2002 Wiley‐Liss, Inc.
TLM models of bending transients and their application to the deformation of thin walled ceramic shapes
Authors: Newton H. R. , Pulko S. H. , Wilkinson A. J.
Published: October 2002

A transmission line matrix model of viscous bending under gravity is devised. This is initially extended to a two‐component, parallel, dashpot‐spring model corresponding to a Kelvin solid, and then to a three‐component model comprising an initial elastic deflection followed by a slow viscoelastic deformation. This three‐component model is used to predict the deformation of thin walled ceramic shapes during firing. Predicted deformations and those observed in fired ceramic pieces are compared for three types of ceramic shape; bars supported as cantilevers, vertical hoops and three‐dimensional ‘mushroom’ shaped shells. Copyright © 2002 John Wiley & Sons, Ltd.
γ‐aminobutyric acid transporter (BGT‐1) expressed in human astrocytoma U373 MG cells: Pharmacological and molecular characterization and phorbol ester‐induced inhibition
Authors: Ruiz‐Tachiquín M.‐E. , Sánchez‐Lemus E. , Soria‐Jasso L.‐E. , Arias‐Montaño J.‐A. , Ortega A.
Published: October 2002

The properties of a transport system specific for γ‐aminobutyric acid (GABA) expressed in human U373 MG astrocytoma cells were examined. The uptake of [3H]GABA was dependent on both extracellular Na+ and Cl– ions and was inhibited by (±)‐nipecotic acid, guvacine, and β‐alanine, with a pharmacological profile corresponding to that reported for the human homologue of the GABA/betaine transporter (BGT‐1). Accordingly, [3H]GABA uptake was also inhibited by betaine, and reverse transcriptase‐polymerase chain reaction (RT‐PCR) analysis of total RNA from U373 MG cells with specific BGT‐1 primers resulted in the amplification of a 440 bp fragment that was further characterized by restriction analysis and sequencing. In addition, Western blot analysis with anti‐BGT‐1 antiserum revealed the presence of a characteristic 60 kDa band. The primary structure of the human BGT‐1 protein predicts two putative phosphorylation sites for the Ca2+/diacylglicerol‐dependent protein kinase (PKC), and treatment of U373 MG cells with the PKC activator phorbol 12‐myristate‐13‐acetate (TPA) led to a concentration‐ and time‐dependent decrease in [3H]GABA uptake. The maximal effect was detected at 2 hr of incubation, to disappear after 4 hr. TPA‐induced reduction in [3H]GABA uptake was reversed by preincubation with staurosporine. Taken together, these results indicate that U373 MG cells express a GABA transporter of the BGT‐1 subtype whose function is regulated by phosphorylation events through PKC. © 2002 Wiley‐Liss, Inc.
Expression of inducible nitric oxide synthase and cyclooxygenase‐2 after excitotoxic damage to the immature rat brain
Authors: Acarin Laia , Peluffo Hugo , González Berta , Castellano Bernardo
Published: October 2002

It is well established that after adult brain damage the enzymes cyclooxygenase‐2 (COX‐2) and inducible nitric oxide synthase (iNOS) play an important role in the inflammatory processes and oxidative stress, which are considered to be the leading factors contributing to delayed cell death. The contribution of these enzymes to postnatal brain damage, however, is poorly understood. In our study, excitotoxic lesions were induced by the injection of N‐methyl‐D‐aspartate in the cortex of postnatal day 9 rats. After different survival times ranging from 4 hr to 7 days post‐lesion, brain sections were processed for the immunocytochemical demonstration of COX‐2 and iNOS and double labeling with neuronal, glial and neutrophil markers. First and maximal de novo induction of iNOS and COX‐2 expression was found at 10 hr post‐lesion. Expression of both enzymes started to diminish at 24 hr, reaching basal levels at day 3. iNOS‐expressing cells were mainly identified as infiltrated neutrophils as well as highly ramified protoplasmic astrocytes closely associated with blood vessels. Moreover, scattered iNOS‐positive neurons were found at the lesion borders. In contrast, COX‐2 was mainly observed in reactive microglial cells and neuronal cells. COX‐2‐positive neurons were found within the degenerating area at 10 hr and at the borders of the lesion later on. This study shows that maximal iNOS and COX‐2 expression precedes the period of massive neuronal death observed at 24 hr post‐lesion, and may therefore contribute to the evolution of the inflammatory response and the neurodegenerative process after an excitotoxic lesion to the postnatal brain. © 2002 Wiley‐Liss, Inc.
GeneChip® analysis shows altered mRNA expression of transcripts of neurotransmitter and signal transduction pathways in the cerebral cortex of portacaval shunted rats
Authors: Song Guoqing , Dhodda Vinay K. , Blei Andres T. , Dempsey Robert J. , Rao Vemuganti L. Raghavendra
Published: October 2002

Identifying the gene expression changes induced by hepatic encephalopathy (HE) leads to a better understanding of the molecular mechanisms of HE‐induced neurological dysfunction. Using GeneChip® and real‐time PCR, the present study evaluated the gene expression profile of rat cerebral cortex at 4 weeks after portacaval shunting. Among 1,263 transcripts represented on the chip, mRNA levels of 31 transcripts were altered (greater than twofold; 16 increased and 15 decreased) in the portacaval shunted (PCS) rat compared to sham control. Changes observed by GeneChip® analysis were confirmed for 20 transcripts (8 increased, 7 decreased, and 5 unchanged in PCS rat brain) by real‐time PCR. Neurotransmitter receptors, transporters, and members of the second messenger signal transduction are the major groups of genes altered in PCS rat brain. Of importance was that the increased heme oxygenase‐1 and decreased Cu,Zn‐superoxide dismutase expression observed raise the possibility of oxidative stress playing a pathogenic role in chronic HE. © 2002 Wiley‐Liss, Inc.
Immunoglobulin Fcγ receptor promotes immunoglobulin uptake, immunoglobulin‐mediated calcium increase, and neurotransmitter release in motor neurons
Authors: Mohamed Habib A. , Mosier Dennis R. , Zou Ling L. , Siklós László , Alexianu Maria E. , Engelhardt Jozsef I. , Beers David R. , Le Wei‐dong , Appel Stanley H.
Published: October 2002

Receptors for the Fc portion of immunoglobulin G (IgG; FcγRs) facilitate IgG uptake by effector cells as well as cellular responses initiated by IgG binding. In earlier studies, we demonstrated that amyotrophic lateral sclerosis (ALS) patient IgG can be taken up by motor neuron terminals and transported retrogradely to the cell body and can alter the function of neuromuscular synapses, such as increasing intracellular calcium and spontaneous transmitter release from motor axon terminals after passive transfer. In the present study, we examined whether FcγR‐mediated processes can contribute to these effects of ALS patient immunoglobulins. F(ab′)2 fragments (which lack the Fc portion) of ALS patient IgG were not taken up by motor axon terminals and were not retrogradely transported. Furthermore, in a genetically modified mouse lacking the γ subunit of the FcR, the uptake of whole ALS IgG and its ability to enhance intracellular calcium and acetylcholine release were markedly attenuated. These data suggest that FcγRs appear to participate in IgG uptake into motor neurons as well as IgG‐mediated increases in intracellular calcium and acetylcholine release from motor axon terminals. © 2002 Wiley‐Liss, Inc.
Neuroprotection of glial cell line‐derived neurotrophic factor in damaged spinal cords following contusive injury
Authors: Cheng Henrich , Wu Jey‐Pei , Tzeng Shun‐Fen
Published: October 2002

Glial cell line‐derived neurotrophic factor (GDNF) acts as a potent survival factor for many neuronal populations, including spinal motoneurons, indicating the therapeutic promise of GDNF for neurological disorders. Injury to spinal cord (SCI) triggers processes destructive to ascending sensory and descending motor conduction and extends tissue loss, thereby leading to permanent behavioral dysfunction. In this study, we attempted to examine whether GDNF protects neurons from SCI and subsequently lessens locomotor deficit in SCI rats. We utilized the NYU weight‐drop device developed at New York University to induce spinal cord contusion at the T9–10 spinal segment. After SCI, GDNF was administrated into the cord 1–2 mm rostral and caudal to the epicenter. Animals receiving GDNF treatment showed significant improvement over phosphate‐buffered saline (PBS)‐treated controls on the Basso Beattie Bresnahan (BBB) locomotor rating scale (P < 0.01‐0.001). GDNF treatment increased the remaining neuronal fibers with calcitonin gene‐related peptide, neurofilament, and growth‐associated protein 43 immunoreactivity in injured spinal tissues compared with PBS‐treated controls. Moreover, treatment with GDNF caused approximately 50% cell survival in the contused spinal cord tissues. Examination of signal transduction triggered by GDNF indicated that GDNF injection transiently induced activation of the mitogen‐activated protein (MAP) kinase pathway in the spinal cord. Additionally, an up‐regulation of anti‐apoptotic Bcl‐2 levels in the contusive center of the damaged spinal cord was observed 24 hr post‐GDNF injection. Together our results show that GDNF exerts behavioral and anatomic neuroprotection following SCI. Additionally, GDNF‐activated MAP kinase and Bcl‐2 signaling may contribute to neuronal survival after spinal cord contusion. © 2002 Wiley‐Liss, Inc.
Neural (N‐) cadherin, a synaptic adhesion molecule, is induced in hippocampal mossy fiber axonal sprouts by seizure
Authors: Shan Weisong , Yoshida Mika , Wu Xi‐Ru , Huntley George W. , Colman David R.
Published: October 2002

Aberrant mossy fiber sprouting and synaptic reorganization are plastic responses in human temporal lobe epilepsy, and in pilocarpine‐induced epilepsy in rodents. Although the morphological features of the hippocampal epileptic reaction have been well documented, the molecular mechanisms underlying these structural changes are not understood. The classic cadherins, calcium‐dependent cell adhesion molecules, are known to function in development in neurite outgrowth, synapse formation, and stabilization. In pilocarpine‐induced status epilepticus, the expression of N‐cadherin mRNA was sharply upregulated and reached a maximum level (1‐ to 2.5‐fold) at 1– to 4 weeks postseizure in the granule cell layer and the pyramidal cell layer of CA3. N‐cadherin protein was correspondingly increased and became concentrated in the inner molecular layer of the dentate gyrus, consistent with the position of mossy fiber axonal sprouts. Moreover, N‐cadherin labeling was punctate; colocalized with definitive synaptic markers, and partially localized on polysialated forms of neural cell adhesion molecule (PSA‐NCAM)‐positive dendrites of granule cells in the inner molecular layer. Our findings show that N‐cadherin is likely to be a key factor in responsive synaptogenesis following status epilepticus, where it functions as a mediator of de novo synapse formation. © 2002 Wiley‐Liss, Inc.
Neurons overexpressing mutant presenilin‐1 are more sensitive to apoptosis induced by endoplasmic reticulum‐Golgi stress
Authors: Terro Faraj , Czech Christian , Esclaire Françoise , Elyaman Wassim , Yardin Catherine , Baclet Marie‐Claire , Touchet Nathalie , Tremp Günter , Pradier Laurent , Hugon Jacques
Published: October 2002

Most early‐onset cases of familial Alzheimer's disease (FAD) are linked to mutations in two related genes, ps1 and ps2. FAD‐linked mutant PS1 alters proteolytic processing of the amyloid precursor protein and increases vulnerability to apoptosis induced by various cell stresses. In transfected cell lines, mutations in ps1 decrease the unfolded‐protein response (UPR), which is the response to the increased amounts of unfolded proteins that accumulate in the endoplamic reticulum (ER), indicating that these mutations may increase vulnerability to ER stress by altering the UPR signalling pathway. Here we report that, in primary cultured neurons from cortices of transgenic mice, overexpression of mutated PS1 (M146L mutation) but not PS1 wild‐type (wt) enhanced spontaneous neuronal apoptosis that involved oxidative stress and caspase activation. In PS1M146L cultures, neurons displaying immunoreactivity for human PS1 were threefold more vulnerable to spontaneous apoptosis than the overall neuronal population. In addition, PS1M146L transgenic neurons were more sensitive to apoptosis induced by various stresses, including two ER‐Golgi toxins, nordihydroguaiatric acid and brefeldin A (also known to induce UPR), as well as staurosporine. In contrast, PS1 wt transgenic neurons were resistant to apoptosis induced by Golgi‐ER toxins but displayed a comparable vulnerability to staurosporine. Our study demonstrates that, as previously reported, overexpression of FAD‐linked mutant PS1 enhances neuronal vulnerability to spontaneous and induced apoptosis. In addition, we show that this vulnerability was correlated with mutant PS1 protein expression and that PS1 wt overexpression selectively prevented ER‐Golgi stress‐induced apoptosis. These data indicate that PS1 interferes with a specific apoptotic pathway that results from a dysfunction of the ER‐Golgi compartment. © 2002 Wiley‐Liss, Inc.
Re‐evaluation of trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999
Authors: Türkeş Murat , Sümer Utku M. , Demi̇r İsmai̇l
Published: October 2002

Mean, maximum and minimum surface air temperatures recorded at 70 climatological stations in Turkey during the period from 1929 to 1999 were analysed to reveal spatial and temporal patterns of long‐term trends, change points, significant warming (cooling) periods and linear trend rates per decade. Annual, winter and spring mean temperatures have tended to increase, particularly over the southern regions of Turkey, whereas summer and particularly autumn mean temperatures have decreased over the northern and continental inner regions. Annual, winter, spring and summer maximum temperatures have indicated a positive trend at many stations, except those in the Central Anatolia and Black Sea regions and partly in the Eastern Anatolia region. Autumn maximum temperatures, however, have decreased slightly over much of Turkey, except for the Aegean region. The majority of the urbanized and rapidly urbanizing stations in Turkey have been experiencing an apparent night‐time warming, especially during the warm and dry period of the year. Minimum temperatures have shown a statistically significant positive trend at 31 stations annually, 30 stations in spring and 33 stations in summer; most are significant at the 0.01 level. Winter and autumn minimum temperatures have indicated a general negative trend in some portions of the Marmara, Black Sea and Eastern Anatolia regions, whereas a general positive trend has been seen over much of Turkey along with the significant trends in the Mediterranean region of the country.

Summer night‐time warming rates are generally larger than in spring and autumn night‐time temperatures. On the other hand, the night‐time warming rates of spring and summer are generally stronger than those in spring and summer daytime temperatures. By considering the marked increasing trends in spring, summer and annual minimum temperatures of urban stations, we have recognized that this is a clear and significant indication for the existence of a strong night‐time urban warming in Turkey. Copyright © 2002 Royal Meteorological Society.
Weichselian sediments at Foss‐Eikeland, Jæren (southwest Norway): sea‐level changes and glaciation history
Authors: Raunholm S. , Larsen E. , Sejrup H. P
Published: October 2002

The Jæren area in southwestern Norway has experienced great changes in sea‐levels and sedimentary environments during the Weichselian, and some of these changes are recorded at Foss‐Eikeland. Four diamictons interbedded with glaciomarine and glaciofluvial sediments are exposed in a large gravel pit situated above the post‐glacial marine limit. The interpretation of these sediments has implications for the history of both the inland ice and the Norwegian Channel Ice Stream. During a Middle Weichselian interstadial, a large glaciofluvial delta prograded into a shallow marine environment along the coast of Jæren. A minor glacial advance deposited a gravelly diamicton, and a glaciomarine diamicton was deposited during a following marine transgression. This subsequently was reworked by grounded ice, forming a well‐defined boulder pavement. The boulder pavement is followed by glaciomarine clay with a lower, laminated part and an upper part of sandy clay. The laminated clay probably was deposited under sea‐ice, whereas more open glaciomarine conditions prevailed during deposition of the upper part. The clay is intersected by clastic dykes protruding from the overlying, late Weichselian till. Preconsolidation values from the marine clay suggest an ice thickness of at least 500 m during the last glacial phase. The large variations in sea‐level probably are a combined effect of eustasy and glacio‐isostatic changes caused by an inland ice sheet and an ice stream in the Norwegian Channel. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of controlled atmosphere (CA) storage on pectinmethylesterase (PME) activity and texture of ‘Rocha’ pears
Authors: Galvis Sánchez Andrea C , Morais Alcina M M B
Published: October 2002

Firmness and pectinmethylesterase (PME) activity were evaluated in pears (cv Rocha) after 9 months of storage in controlled atmosphere (CA) followed by various periods of exposure to air at room temperature. The free calcium content was also evaluated in tissues. Fruit firmness decreased with increasing time of air exposure for all four different CA storage conditions tested. After 9 days of air exposure, fruits stored in 2% O2 + 1.5% CO2 were less firm than control fruits (stored in air) and showed higher PME activity. In spite of normal textural changes being observed with increasing time of exposure to air at room temperature, the underlying metabolism might have been affected by CA storage.

© 2001 Society of Chemical Industry
Nephelometric study of salivary protein–tannin aggregates
Authors: Freitas Victor de , Mateus Nuno
Published: October 2002

Grape seed procyanidins were fractionated through different degrees of polymerisation, and human saliva was purified and separated into two fractions: one was mostly α‐amylase and the other was essentially proline‐rich proteins (PRPs). The interaction of these proteins with the procyanidin compounds was assayed using nephelometry, and the influence of several factors was investigated, such as degree of polymerisation, pH and concentrations of both protein and tannin. The same experiments were performed with bovine serum albumin (BSA). The amount of insoluble aggregates, resulting from the formation of polyphenol–protein aggregates, increased quickly up to a maximum value which thereafter remained practically unchanged. pH was set at 5.0 for all further assays, since it was the nearest value to that encountered in human saliva (pH 5.6–7.9), where proteins were stable and had a maximum ability to bind and precipitate procyanidin oligomers. These proteins were shown to have a strong affinity for procyanidin oligomers and were unable to resolubilise the polyphenol–protein aggregates when present in excess. PRPs required a much lower content to bind all the tannins (400 µg of procyanidin oligomers) than BSA and especially α‐amylase (48, 60 and 132 µg respectively). The procyanidin's ability to bind PRPs, BSA and α‐amylase increased with its average molecular weight. This ability increased regularly for PRPs up to 4500 Da, whereas the ability to bind the globular proteins decreased beyond 3400 Da.

© 2001 Society of Chemical Industry
Effect of various dietary fats and proteins on serum cholesterol level in rats
Authors: Hanczakowski Piotr , Szymczyk Beata , Furgał‐Dierżuk Iwona
Published: October 2002

A 60 day experiment on growing rats was performed to evaluate the effect of two protein sources (casein and soybean protein isolate) and four fats (olive oil, OO; evening primrose oil, EO; linseed oil, LO; and butter, B) on plasma lipoprotein fractions: total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol (LDL‐C) and triacylglycerol (TAG) levels. The different protein and fat sources had no influence on body weight gain of rats. Fats had no significant effect on TC and LDL‐C. Significant differences were found only in HDL‐C. OO gave the lowest (43.3 mg dl−1) and EO the highest (54.4 mg dl−1) value. Proteins had a significant influence on all lipids analysed. Soybean protein caused higher TC (78.5 vs 67.9 mg dl−1), HDL‐C and TAG levels but significantly lowered LDL‐C in the plasma of rats. These results suggest that protein has a stronger effect on cholesterol level than fat.

© 2002 Society of Chemical Industry
Phenolic compounds, lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)
Authors: Martínez‐Valverde Isabel , Periago María J , Provan Gordon , Chesson Andrew
Published: October 2002

Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p‐coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59 mg kg−1 fresh weight, while naringenin levels were lower than 12.55 mg kg−1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32 mg kg−1 fresh weight, followed by caffeic acid, while p‐coumaric and ferulic acids showed similar concentrations lower than 5 mg kg−1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50 mg kg−1 fresh weight), while the concentration in the other varieties was between 50 and 30 mg kg−1, with the exception of Liso (less than 20 mg kg−1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid.

© 2002 Society of Chemical Industry
Influence of harvest time on citrus pectin and its in vitro inhibition of fibroblast growth factor signal transduction
Authors: Liu Yan , Ahmad Hassan , Luo Yongde , Gardiner Duane T , Gunasekera Richard S , McKeehan Wallace L , Patil Bhimanagouda S
Published: October 2002

Seasonal changes in pectin content and chemical composition were studied in three anatomical layers of ‘Rio Red’ grapefruit (Citrus paradisi Macf), a currently popular cultivar in the Rio Grande Valley in Texas, USA. Fruits were harvested at intervals between August 1998 and May 1999. Pectin content in flavedo decreased throughout the season, while in albedo and segment membrane the pectin content was lowest in mid‐season (November and January). In all three layers the anhydrogalacturonic acid (AGA) content of pectin was highest in mid‐season. While the methoxyl content (MC) of pectin increased, the total neutral sugar (TNS) content of pectin decreased in all three layers throughout the season. The in vitro effect of grapefruit pectin on fibroblast growth factor (FGF)–FGF receptor (FGFR) interaction was also investigated. The strong interdependence of heparin on factor–receptor interaction provides means for identifying new antagonists of growth factor activity and thus for treatment of various diseases. Our results showed that grapefruit pectin significantly inhibited the binding of FGF‐1 to FGFR1 in the presence of 0.1 µg ml−1 heparin. Pectin of albedo from grapefruits harvested in January was the most potent inhibitor. The in vitro inhibitory activity was significantly correlated with the percentage of rhamnose. Kinetic studies revealed a competitive nature of pectin on FGF signal transduction with heparin. The observation that the biological activity of heparin can be antagonised by citrus pectin suggests that pectins should be investigated further as anti‐growth factor agents for potential health benefits.

© 2002 Society of Chemical Industry
Sensory characterisation of ewe's milk cheeses using direct and indirect similarity measures: a comparison
Authors: Bárcenas Pedro , Pérez Elortondo Francisco J , Salmerón Jesús , Albisu Marta
Published: October 2002

The purpose of the present study is to compare several direct and indirect (profile and hedonic scores) similarity measures. Moreover, the main relationships among assessors, sensory attributes and ewe's milk cheeses have been explored using different statistical techniques. For this purpose, visual inspection and correlation coefficients among cheese sample sensory dimensions have been considered. All the solutions lead to very similar spatial configurations, except for preference data. In this case the considered techniques are very useful tools in the study of sensory attributes. Individual differences among assessors have been demonstrated to be quite high. Thus it is clear that methods that consider this variability in the data should be used, to which end, assessors should undergo specific training depending on the tests to be performed.

© 2002 Society of Chemical Industry
Factor analysis of physicochemical properties of 63 rice varieties
Authors: Tan Yifang , Corke Harold
Published: October 2002

A set of 63 Chinese‐adapted non‐waxy rice varieties of the indica and japonica subspecies was measured to extract simple indicators for rice quality evaluation. Approximate methods including amylose content (AC), gel consistency (GC), gelatinisation temperature (as measured by alkali spreading value, ASV), protein content, etc and instrumental methods including differential scanning calorimetry (DSC), viscoamylography (with a Rapid Visco‐Analyser, RVA) and texture profile analysis were adopted. Four sets of data, ie ordinary testing, flour pasting property, texture of the cooled flour gel, and visual appearance of whole milled grain and flour, were obtained and analysed for mutual relationships. Wide variations were observed in most of the measurements, eg AC (ranging from 6.3 to 28.2%), gelatinisation temperature (Tp, 65.8–83.0 °C), protein content (7.2–13.5%), pasting (peak viscosity, 92–319 RVU) and texture (hardness, 2.5–24.4 g) properties and grain appearance (grain length, 4.8–8.4 mm), to mention a few. Significant correlations were also detected among the four sets of data of the rice varieties, such as AC versus SB (setback viscosity) with a correlation coefficient of −0.73, AC versus HRD (gel hardness) of 0.73, HRD versus FRC (gel fracturability) of 0.99, etc. Generally, the instrumental measurements including DSC, pasting and texture properties were highly correlated with the three ordinarily used indicators of rice quality, ie AC, GC and ASV. However, there was a lack of correlation between pasting properties and textural parameters, implying effects on gel texture of retrogradation of starch after cooling of the paste. Six factors were computed by principal component factor analysis that explained 80% of the variation in the traits, among which amylose content‐related (30.8%), gelatinisation temperature‐related (14.9%) and grain appearance‐related (11.1%) factors were most important. Gel pasting properties evaluated by RVA, and flour colour played less important roles in explaining total variation (accounting for a combined 23% of the eigenvalue loading). This report can be used to identify predictive parameters for rapid screening of rice genotypes for eating quality.

© 2002 Society of Chemical Industry
Identification of odour‐active compounds in muscle of brown trout (Salmo trutta) as affected by dietary lipid sources
Authors: Sérot Thierry , Regost Christelle , Arzel Jacqueline
Published: October 2002

The effect of fatty acid composition on odour‐active compounds in brown trout (Salmo trutta) muscle was evaluated. The fillets were obtained from three groups of fish fed experimental diets containing either fish oil (FO), soybean oil (SO) or linseed oil (LO). Muscle fatty acid composition was shown to be influenced by diet. Thirty‐one odorous compounds were detected by gas chromatography/olfactometry (frequency‐of‐detection method). Most of these compounds were formed by the oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐pentenal, (E)‐2‐pentenol and (E)‐2‐hexenol contribute strongly to the odour of brown trout. (E,Z)‐2,4‐Heptadienal was detected with high frequency in fish fed diets containing high levels of n‐3 PUFAs (FO and LO groups). Hexanal, (E)‐2‐hexenal and 2‐nonanol seem to contribute most to the odour of fish fed diets containing vegetable oils. Many odorous compounds were derived from the oxidation of mono‐ and di‐unsaturated fatty acids, which could be promoted by high levels of PUFAs.

© 2002 Society of Chemical Industry
Analysis of vicilin (7S)‐class globulin in cocoa cotyledons from various genetic origins
Authors: Amin I , Jinap S , Jamilah B , Harikrisna K , Biehl B
Published: October 2002

Cocoa cotyledons contain vicilin (7S)‐class globulin (VCG), a major storage protein. It is the native source of oligopeptides and free amino acids which have been identified as precursors of cocoa‐specific aroma and are formed through proteolysis during fermentation. High‐resolution electrophoresis of native proteins isolated from ripe, unfermented cocoa cotyledons harvested from different cultivars was used to determine genetic differences of the genotypes. Flavour differences have been reported to exist after standard fermentation in cocoa beans harvested from various genotypes. In this paper, SDS‐PAGE and 2D IEF/SDS‐PAGE polypeptide separation patterns are shown which were separately isolated from cotyledons of various genetic origins. Cotyledons from three cultivars belonging to genetically distant varieties and a hybrid, Criollo, Forastero and Trinitario, did not reveal any analytical identity differences of VCG subunit polypeptide bands. Additionally, proteins of cotyledons harvested from three of those clones which were reported to produce genotype‐specific flavour differences in raw cocoa after standard fermentation, SCA 12, UIT1 and PBC 140, when analysed in the same way, did not indicate differences. Thus the cotyledon storage proteins from various genetically different cocoa trees are, within methodological limits, the same. We conclude that aroma differences in raw cocoa harvested from various genotypes are the result of other genetic, physiological or curing‐related factors, but are not due to genetic differences of aroma precursors derived from storage proteins.

© 2002 Society of Chemical Industry
Modified atmosphere packaging of filleted rainbow trout
Authors: Giménez Begoña , Roncalés Pedro , Beltrán Jose A
Published: October 2002

Shelf‐lives of filleted rainbow trout (Oncorhynchus mykiss) packaged in over‐wrap, vacuum and gas mixture conditions and stored at 1 ± 1 °C were compared by measurement of pH, total volatile bases (TVB), hypoxanthine content, lipid oxidation (TBARS value), superficial counts of aerobic psychrotrophic flora and sensory analysis (colour, odour and flavour). The gas mixtures evaluated were 10% O2 + 50% CO2 + 40% N2, 10% O2 + 50% CO2 + 40% Ar, 20% O2 + 50% CO2 + 30% N2, 20% O2 + 50% CO2 + 30% Ar, 30% O2 + 50% CO2 + 20% N2 and 30% O2 + 50% CO2 + 20% Ar. Sensory quality deterioration was delayed and bacterial growth as well as increases in pH, TVB and hypoxanthine levels were reduced by modified atmosphere packaging (MAP). Lipid oxidation was higher in gas packages with 20 and 30% O2 than in those with 10% O2. Vacuum‐packed fillets presented the lowest TBARS values. In summary, MAP gave rise to a significant extension of shelf‐life when compared with vacuum and over‐wrap packaging. No significant differences were found between the packages containing either N2 or Ar. The best evaluated atmosphere consisted of 10% O2 + 50%CO2 + 40% N2/Ar.

© 2002 Society of Chemical Industry
Simultaneous quantification of the main organic acids and carbohydrates involved in tomato flavour using capillary zone electrophoresis
Authors: Roselló Salvador , Galiana‐Balaguer Luis , Herrero‐Martínez José Manuel , Maquieira Angel , Nuez Fernando
Published: October 2002

A capillary zone electrophoresis (CZE) procedure for the simultaneous determination of the major organic acids (oxalate, malate and citrate) and carbohydrates (fructose, glucose and sucrose) in Lycopersicon fruits is reported. Comparison of this method with routine HPLC methods indicates that the CZE method offers several attractive features (speed, resolution, sensitivity and cost) which significantly improve the determination of these compounds. Detection limits were better than 1.6 µg ml−1 for organic acids and from 13 to 24 µg ml−1 for carbohydrates; repeatabilities were better than 2.1% for migration times and between 1.4 and 7.3% for peak areas. The proposed protocol is very useful to characterise large series of tomato samples not only in breeding programmes but also in systematic and routine analysis in the tomato industry.

© 2002 Society of Chemical Industry
Effects of maize grain size, shape and hardness on drying rate and the occurrence of stress cracks
Authors: Kim Tae Hoon , Hampton John G , Opara Linus U , Hardacre Allan K , Mackay Bruce R
Published: October 2002

The effects of maize (Zea mays L) grain hardness, morphological factors (grain size and shape), drying rate and the development of stress cracking over time were investigated for four hybrids (Hmv565 − 3 × E1386, CF06, CF05 and Furio). The re‐parametrised Morgan–Mercer–Flodin (MMF) model successfully predicted the rate (κ) and maximum value (α) of percentage checked stress cracking (checking) in various sizes, shapes and hardnesses of grains with time after drying. The maximum percentage checking (α) was significantly correlated with grain length (r = −0.707), thickness (r = 0.620), roundness (r = 0.703) and the shortest diffusion pathway (r = 0.627). The rate (κ) of percentage checking with time after drying was significantly correlated with grain bulk density (r = −0.564), hardness ratio (r = −0.611) and drying rate (r = 0.551) and, to a lesser extent, with grain size parameters including hundred‐grain weight, grain length and width. Removing small and round grains could reduce checked stress cracking by up to 50% in some dent maize hybrids.

© 2002 Society of Chemical Industry