bluuebunny/crossref_metadata_2025 huggingface dataset:
Age-Dependent Regulation of Lipogenesis in Human and Rat Adipocytes
Authors: Kamel Ashraf F. , Norgren Svante , Strigård Karin , Thörne Anders , Fakhrai-Rad Hossein , Galli Joakim , Marcus Claude
Published: September 2004

The regulation of adipocyte metabolism is of importance for adipose tissue growth and therefore also for the development of obesity. This study was designed to investigate the regulation of basal and insulin-induced lipogenesis, glucose transport, and glucose transporter protein expression in human and rat adipocytes from different age groups.

The study included 21 infants, 21 children, nine adults, and 80 male weaned and 20 male adult Fischer rats. The lipogenesis experiments were performed under conditions at which glucose transport is rate limiting. Basal lipogenesis was approximately three times higher in infants and children than in adults, whereas insulin-induced lipogenesis was two times higher in infants than in children and adults. In rats, basal lipogenesis, insulin-induced lipogenesis, and insulin sensitivity were two times higher in weaned than in adult animals. Moreover, basal and insulin-induced glucose transport were two times higher in weaned than in adult rats. No differences were detected in GLUT1 or GLUT4 content between any of the age groups in human or in rat adipocytes.

In conclusion, basal and insulin-stimulated lipogenesis are increased in adipocytes early in life. This may promote adipose tissue growth in early age. The data indicate that age-dependent variation in basal and insulin-stimulated lipogenesis is differently regulated.
Responses of Lipolysis and Salivary Cortisol to Food Intake and Physical Activity in Lean and Obese Children
Authors: Hershberger A. M. , McCammon M. R. , Garry J. P. , Mahar M. T. , Hickner R. C.
Published: September 2004

This investigation was conducted to determine whether there were differences in lipolytic responses to feeding and physical activity between lean (LN) and obese (OB) children, and if these responses were related to cortisol. Fourteen LN and 11 OB children participated in this study of abdominal lipolysis and salivary cortisol response to breakfast and lunch with an intervening exercise session. Calculated fasting glycerol release was lower in OB than LN (0.645 ± 0.06 vs. 0.942 ± 0.11 μmol/ml; P < 0.05). Fasting adipose tissue nutritive flow was lower in OB than in LN subjects, but responses to feeding and exercise were not different. Breakfast elicited a decrease in interstitial glycerol concentration in LN (−33%; P < 0.05), but not in OB (−5%), children, although decreases in glycerol concentration in response to lunch were similar (LN, −41%; OB, −36%). An interaction was evident in the salivary cortisol response to breakfast (LN, no change; OB, increase) and exercise (LN, no change; OB, decrease), but there were no group differences in response to lunch. Alterations in salivary cortisol and lipolysis were not related. These data suggest that salivary cortisol and lipolytic responses are not necessarily linked, but are altered in obesity. Furthermore, prior exercise may improve the antilipolytic response to a meal in OB children.
Differential Cellular Handling of Defective Arginine Vasopressin (AVP) Prohormones in Cells Expressing Mutations of the AVP Gene Associated with Autosomal Dominant and Recessive Familial Neurohypophyseal Diabetes Insipidus
Authors: Christensen Jane H. , Siggaard Charlotte , Corydon Thomas J. , Robertson Gary L. , Gregersen Niels , Bolund Lars , Rittig Søren
Published: September 2004

An unusual mutation in the arginine vasopressin (AVP) gene, predicting a P26L amino acid substitution of the AVP prohormone, is associated with autosomal recessive familial neurohypophyseal diabetes insipidus (FNDI). To investigate whether the cellular handling of the P26L prohormone differed from that of the Y21H prohormone associated with autosomal dominant inheritance of FNDI, the mutations were examined by heterologous expression in cell lines. Immunoprecipitation demonstrated retarded processing and secretion of the Y21H prohormone, whereas the secretion of the P26L prohormone seemed to be unaffected. Confocal laser scanning microscopy showed accumulation of the Y21H prohormone in the endoplasmic reticulum, whereas the P26L prohormone and/or processed products were localized in secretory granules in the cellular processes. RIA analysis showed reduced amounts of immunoreactive Y21H-AVP and P26L-AVP in the cell culture medium. Thus, the recessive mutation does not seem to affect the intracellular trafficking but rather the final processing of the prohormone. Our results provide an important negative control in support of the hypothesis that autosomal dominant inheritance of FNDI is caused by mutations in the AVP gene that alter amino acid residues important for folding and/or dimerization of the neurophysin II moiety of the AVP prohormone and subsequent transport from the endoplasmic reticulum.
Increase in 6-Hydroxymelatonin Excretion in Humans during Ascent to High Altitudes
Authors: Frisch Herwig , Waldhauser Franz , Waldhör Thomas , Müllner-Eidenböck Andrea , Neupane Pritam , Schweitzer Katharina
Published: September 2004

Melatonin (MLT), the pineal gland hormone involved in the regulation of circadian rhythms, shows characteristic diurnal variation. Its physiological role in humans is not clear. Exposure to high altitudes may disrupt the circadian rhythm and lead to various endocrine changes. MLT in humans has not been studied under these conditions. Urinary 6-hydroxy-MLT sulfate (aMT6s) excretion was analyzed during the day (0700–2200 h) and night (2200–0700 h) phases. A cohort of 33 healthy volunteers, aged 19–65 yr, was studied during an ascent to a high altitude in the Himalayas on three occasions (at a lower altitude, at 3400 m, and after reaching maximal altitudes of 5600–6100 m). aMT6s excretion during the daytime remained unchanged during exposure to high altitudes. As expected, nocturnal values were higher than diurnal values at each point in time. However, there was a significant increase in nocturnal MLT excretion after the ascent to high altitudes. Ascent to high altitudes is associated with increased nocturnal excretion of aMT6s. The mechanism and physiological significance of this MLT increase are unclear.
Antiinflammatory Steroid Action in Human Ovarian Surface Epithelial Cells
Authors: Rae Michael T. , Niven Deborah , Critchley Hilary O. D. , Harlow Christopher R. , Hillier Stephen G.
Published: September 2004

The human ovarian surface epithelium (OSE) is subject to serial injury and repair during ovulation, which is a natural inflammatory event. We asked whether there is a compensatory antiinflammatory component to this process, involving steroid hormones produced locally at the time of ovulation. Quantitative RT-PCR analysis of total RNA from cultured human OSE cell monolayers showed that exposure to proinflammatory IL1α (500 pg/ml) increased mRNA levels of cyclooxygenase-2 (COX-2) (P < 0.01) at 48 h. The COX-2 mRNA response to IL1α was associated with an approximate 18-fold (P < 0.01) increase in mRNA levels of 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1), encoding the steroid dehydrogenase that reversibly reduces cortisone to antiinflammatory cortisol. Addition of cortisol to OSE cell culture medium dose-dependently suppressed the COX-2 mRNA response to IL1α (P < 0.01) but reciprocally enhanced the 11βHSD1 mRNA response (P < 0.05), with both effects strongest at 1 μm cortisol. Presence of glucocorticoid receptor-α mRNA and protein was established in OSE cell monolayers and treatment with IL1α shown to significantly up-regulate the glucocorticoid receptor-α mRNA level (P < 0.05). Glucocorticoid receptor antagonist (RU486, 10 μm) fully reversed the inhibitory effect of 1 μm cortisol on IL1α-stimulated COX-2 mRNA expression. Progesterone also suppressed IL1α-induced COX-2 mRNA expression but had no significant effect on IL1α-stimulated 11βHSD1 expression. These data provide direct evidence for antiinflammatory actions of cortisol and progesterone in human OSE cells.
Optimization of size of vehicle and flow domain for underhood airflow simulation
Authors: Huang K D , Tzeng S C
Published: September 2004

The sensitivity of the size of a model vehicle and the flow domain to the flowrate of air through the radiator has been systematically investigated. The sizes of the upstream flow domain in the x, y and z directions are determined by the front flow domain size, the top flow domain size and the side flow domain size respectively. As the size of the front, top or side domain falls below some critical value, the underhood air flowrate dramatically increases. The increase depends on the size of the front flow domain. Therefore, the front, top or side flow domain size significantly affects the underhood air flowrate only when the front, top or side domain is less than a specific length. Graphical results can be easily used to determine the size of the vehicle model and the flow domain that is required to underhood air flow simulation. Finally, the simulated vehicle flow domain sizes are compared with experimentally determined values. The comparison shows that the computed air flowrate through the radiator for the recommended vehicle and flow domain size agrees closely with the test data.
Development and test of a motor vehicle event data recorder
Authors: Lee Wonhee , Han Inhwan
Published: September 2004

A type of event data recorder (EDR) has been developed that can detect a crash automatically, and also record the motion of the vehicle and driver's actions during a predefined time period before and after the accident. The EDR consists of crash detection and vehicle motion sensors, a steering sensor, several digital input ports for detecting the driver's actions, a non-volatile memory device for recording and a microprocessor for controlling the unit. For reliable detection of accident-related crashes, it is important to understand the characteristics of the crash signal, which are very different from those of normal driving. Therefore, analytical considerations were taken in designing prefiltering circuits and selecting the appropriate parameters for identifying a crash. It is also necessary to select a proper combination of motion sensors and to design proper prefiltering circuits in order adequately to describe the motion of the vehicle. Analysis algorithms have been developed and implemented in order reliably to detect a crash, simulate precrash trajectories, and calculate velocity change, δD V, and PDOF for reconstruction analysis of crash accidents. The developed EDR was installed on passenger cars and several types of tests were conducted in order to validate the accuracy of the recorded data and usefulness of the analysis tool for reconstruction.
Acceleration support by integrated starter/alternator for automotive applications
Authors: Jayabalan R , Emadi A
Published: September 2004

The integrated starter / alternator (ISA) of high power generation capacities is able to address increasing power demands in land vehicles. This paper seeks to demonstrate that ISA's design, performance capabilities, and operating effciency indicate that its application can be extended to functionalities such as acceleration support. The incorporation of ISA in conventional vehicles with acceleration support features enables the vehicle to accelerate faster, ensures more reliable and smoother acceleration, provides enhanced manoeuvrability, lowers the stress as well as the response time of the internal combustion engine (ICE), and improves overall vehicle efficiency. Furthermore, acceleration support contributes towards improving fuel economy and the lowering of emissions. This paper presents an approach towards achieving acceleration support by ISA using ADVISOR as the design test tool.
Review of automotive brake friction materials
Authors: Chan D , Stachowiak G W
Published: September 2004

The gradual phasing-out of asbestos in automotive brake friction materials in many parts of the world has sparked the onset of extensive research and development into safer alternatives. As a result, the brake friction industry has seen the birth of different brake pads and shoes in the past decade, each with their own unique composition, yet performing the very same task and claiming to be better than others. This suggests that the selection of brake friction materials is based more on tradition and experimental trial and error rather than fundamental understanding. This review strives to eliminate the cloud of uncertainty by providing an insight into the pros and cons of the common ingredients and make-up used in contemporary dry and wet friction pads and shoes. In this paper typical brake materials are reviewed and their advantages and disadvantages in contemporary brake applications are discussed.
ACTISEAT: Active vehicle seat for acceleration compensation
Authors: Frechin M M , Ariño S B , Fontaine J
Published: September 2004

This paper describes an active vehicle seat to isolate the equipment and passengers in a vehicle from vibration and to compensate, to a certain extent, for acceleration in all directions. The main objective of this system is to reduce the negative effects of vibration and acceleration on embarked equipment and passengers. The active seat is composed of three main subsystems:

A motion sensor unit installed on the vehicle body, to acquire the main motion parameters of the vehicle: speeds, accelerations, inclinations, etc. A small motion base attached to the seat. This platform moves actively, driven by a set of actuators. A control system for the overall system command.

The seat has been extensively tested and the main results are presented.
Combustion characteristics and heat release analysis of a compression ignition engine operating on a diesel/methanol blend
Authors: Huang Z H , Lu H B , Jiang D M , Zeng K , Liu B , Zhang J Q , Wang X B
Published: September 2004

A stabilized diesel/methanol blend was developed and the combustion characteristics and heat release analysis of this blend was carried out in a compression ignition engine. The study showed that the increase in the methanol mass fraction will result in an increase in the heat release rate in the premixed burning phase and shorten the combustion duration of the diffusive burning phase. Ignition delay increases with the increase in the methanol mass fraction and the behaviour is more obvious at low engine load and high engine speed. The rapid-burn duration varies little with the methanol mass fraction and the total combustion duration decreases with the increase in the methanol mass fraction. At a low engine speed, the centre of heat release curve tends to be close to the top dead centre (TDC), with an increase in the methanol mass fraction at all engine loads and fuel delivery advance angles, the maximum rate of pressure rise and the maximum rate of heat release increase with the increase in the methanol mass fraction. At a high engine speed, the centre of the heat release curve closes to TDC at high engine load and will depart from TDC at low engine load. The maximum rate of pressure rise and heat release gives an increasing trend with the increase of methanol mass fraction at high engine loads. The maximum cylinder pressure increases with the increase of the methanol mass fraction. The presence of oxygen reduces the peak pressure, but the reduction was found to be insensitive to the proportion of oxygen within the 6–11 per cent range of testing.
Turbulence effects on accelerating turbulent premixed combustion
Authors: Liao S Y , Jiang D M , Gao J , Zeng K
Published: September 2004

A detailed research on correlation analyses of turbulent characteristic parameters against turbulent combustion is made for methane / air charges in a combustion bomb, under the moderate turbulence conditions ( u u′ / SL = 0.5-4.5). The effects of turbulence intensity, flame size, and turbulent scale on turbulent combustion have been experimentally investigated. Experimental results report that there exists a linear coefficient, C, to describe the enhancing effectiveness of turbulence on turbulent burning velocity, i.e. turbulent burning velocity can be expressed as ST/ SL = Cu u′/ SL + 1, where C is a function of flame size and turbulent length scale. It is also shown that the linear coefficient, C, increases with the increase of flame size, which indicates that the premixed flames considered are not fully developed ones. The coefficient also decreases with increasing turbulent length scale. Through summarizing the analogical works, one obtains that the coefficient C is also approximately linearly related with normalized flame radius, r / L1
The Renal Protective Effects of Angiotensin II Receptor Blockers in Type 2 Diabetes Mellitus
Authors: Coyle James D , Gardner Stephanie F , White C Michael
Published: September 2004

OBJECTIVE

To review the renal protective effects of angiotensin II receptor blockers (ARBs) in patients with type 2 diabetes mellitus.

DATA SOURCES

A MEDLINE search (1966-March 2004) was completed using irbesartan, candesartan, losartan, valsartan, eprosartan, olmesartan, telmisartan, renal protection, nephropathy, albuminuria, and type 2 diabetes mellitus as key words.

STUDY SELECTION AND DATA EXTRACTION

All identified English-language articles were reviewed. References of the identified sources were used to identify additional articles. Articles representative of the subject matter of our review were included.

DATA SYNTHESIS

ARBs have extensive data showing their renal protective benefits in hypertensive type 2 diabetic patients with microalbuminuria or proteinuria. The benefits are over and above that of blood pressure reduction alone and extend to normotensive diabetic patients as well. Maximizing the ARB dose before adding additional therapies or another renal-protecting agent (angiotensin-converting enzyme [ACE] inhibitor or non-dihydropyridine calcium-channel blocker) may be superior to adding another class of antihypertensive, even if similar blood pressures can be achieved.

CONCLUSIONS

ARBs are an important therapy for hypertensive type 2 diabetic patients and can benefit normotensive diabetic patients as well. ARB dosage optimization or the addition of a second renoprotective agent (ACE inhibitor or non-dihydropyridine calcium-channel blocker) may be important for optimal renoprotection, although further research is clearly needed in this area.
Age-Related Functional Changes of Prefrontal Cortex in Long-Term Memory: A Repetitive Transcranial Magnetic Stimulation Study
Authors: Rossi Simone , Miniussi Carlo , Pasqualetti Patrizio , Babiloni Claudio , Rossini Paolo M. , Cappa Stefano F.
Published: September 2004

Neuroimaging findings suggest that the lateralization of prefrontal cortex activation associated with episodic memory performance is reduced by aging. It is still a matter of debate whether this loss of asymmetry during encoding and retrieval reflects compensatory mechanisms or de-differentiation processes. We addressed this issue by the transient interference produced by repetitive transcranial magnetic stimulation (rTMS), which directly assesses causal relationships between performance and stimulated regions. We compared the effects of rTMS (a rapid-rate train occurring simultaneously to the presentation of memoranda) applied to the left or right dorsolateral prefrontal cortex (DLPFC) on visuospatial recognition memory in 66 healthy subjects divided in two classes of age (<45 and >50 years).

In young subjects, rTMS of the right DLPFC interfered with retrieval more than left DLPFC stimulation. The asymmetry of the effect progressively vanished with aging, as indicated by bilateral interference effects on recognition performance. Conversely, the predominance of left DLPFC effect during encoding was not abolished in elders, thus probing its causal role for encoding along the life span. Findings confirm that the neural correlates of retrieval modify along aging, suggesting that the bilateral engagement of the DLPFC has a compensatory role on the elders' episodic memory performance.
Uptake and Release of Norepinephrine by Serotonergic Terminals in Norepinephrine Transporter Knock-Out Mice: Implications for the Action of Selective Serotonin Reuptake Inhibitors
Authors: Vizi E. Sylvester , Zsilla Gabriella , Caron Marc G. , Kiss János P.
Published: September 2004

Our aim was to investigate the functional properties of the noradrenergic system in genetically modified mice lacking the norepinephrine transporter (NET). We measured the uptake and release of [3H]norepinephrine ([3H]NE) from hippocampal and cortical slices of NET-/-knock-out (KO) and NET+/+wild-type (WT) mice and investigated the presynaptic α2-adenoceptor-mediated modulation of NE releasein vitroandin vivo. The [3H]NE uptake was reduced to 12.6% (hippocampus) and 33.5% (frontal cortex) of WT control in KO mice. The neuronal component of this residual uptake was decreased by 79.4 and 100%, respectively, when a selective serotonin reuptake inhibitor (SSRI) citalopram was present during the loading. The more preserved neuronal release of [3H]NE (hippocampus, 28.1%; frontal cortex, 74.4%; compared with WT) almost completely disappeared in both regions (94.1 and 95.3% decrease compared with KO, respectively) in the presence of citalopram, suggesting that [3H]NE was taken up and released by serotonergic varicosities. This was further supported by the finding that the release of [3H]NE from hippocampal slices of KO mice was not modulated by the α2-adrenoceptor antagonist 7,8-(methylenedioxy)-14-α-hydroxyalloberbane HCl, whereas the endogenous release of NE measured by microdialysis was even more efficiently enhanced by this drug in NET-deficient mice. These experiments indicate that serotonergic varicosities can accumulate and release NE as a result of the heterologous uptake of transmitters. Because the diffusion of NE may be spatially limited by serotonin transporters, the SSRIs, despite their selectivity, might enhance not only serotonergic but also noradrenergic neurotransmission, which might contribute to their antidepressant action.
Lasting Blood-Brain Barrier Disruption Induces Epileptic Focus in the Rat Somatosensory Cortex
Authors: Seiffert Ernst , Dreier Jens P. , Ivens Sebastian , Bechmann Ingo , Tomkins Oren , Heinemann Uwe , Friedman Alon
Published: September 2004

Perturbations in the integrity of the blood-brain barrier have been reported in both humans and animals under numerous pathological conditions. Although the blood-brain barrier prevents the penetration of many blood constituents into the brain extracellular space, the effect of such perturbations on the brain function and their roles in the pathogenesis of cortical diseases are unknown.

In this study we established a model for focal disruption of the blood-brain barrier in the rat cortex by direct application of bile salts. Exposure of the cerebral cortexin vivoto bile salts resulted in long-lasting extravasation of serum albumin to the brain extracellular space and was associated with a prominent activation of astrocytes with no inflammatory response or marked cell loss. Using electrophysiological recordings in brain slices we found that a focus of epileptiform discharges developed within 4-7 d after treatment and could be recorded up to 49 d postoperatively in >60% of slices from treated animals but only rarely (10%) in sham-operated controls. Epileptiform activity involved both glutamatergic and GABAergic neurotransmission. Epileptiform activity was also induced by direct cortical application of native serum, denatured serum, or albumin-containing solution. In contrast, perfusion with serum-adapted electrolyte solution did not induce abnormal activity, thereby suggesting that the exposure of the serum-devoid brain environment to serum proteins underlies epileptogenesis in the blood-brain barrier-disrupted cortex. Although many neuropathologies entail a compromised blood-brain barrier, this is the first direct evidence that it may have a role in the pathogenesis of focal cortical epilepsy, a common neurological disease.
The Upregulated Expression of Sonic Hedgehog in Motor Neurons after Rat Facial Nerve Axotomy
Authors: Akazawa Chihiro , Tsuzuki Hayami , Nakamura Yasuko , Sasaki Yo , Ohsaki Kanae , Nakamura Shun , Arakawa Yoshihiro , Kohsaka Shinichi
Published: September 2004

Nerve injury leads to the induction of a large number of genes to repair the damage and to restore synaptic transmission. We have attempted to identify molecules whose mRNA expression is altered in response to facial nerve axotomy. Here we report that facial nerve axotomy upregulates Sonic hedgehog (Shh) and its receptor Smoothened (Smo) in facial motor neurons of adult rats, whereas facial nerve axotomy does not upregulate mRNA of Shh or Smo in neonatal rats. We tested whether overexpression of Shh in facial motor neurons of axotomized neonatal rats may promote neuronal survival. Adenovirus-mediated overexpression of Shh, but not that ofβ-galactosidase, transiently rescues axotomy-induced neuronal cell death for 3-5 d after axotomy. Finally, the pharmacological inhibitor of Shh signaling, cyclopamine, induces motor neuron death in adult rats after axotomy. These results suggest that Shh plays a regulatory role in nerve injury.
Mitochondrial α-Ketoglutarate Dehydrogenase Complex Generates Reactive Oxygen Species
Authors: Starkov Anatoly A. , Fiskum Gary , Chinopoulos Christos , Lorenzo Beverly J. , Browne Susan E. , Patel Mulchand S. , Beal M. Flint
Published: September 2004

Mitochondria-produced reactive oxygen species (ROS) are thought to contribute to cell death caused by a multitude of pathological conditions. The molecular sites of mitochondrial ROS production are not well established but are generally thought to be located in complex I and complex III of the electron transport chain. We measured H2O2production, respiration, and NADPH reduction level in rat brain mitochondria oxidizing a variety of respiratory substrates. Under conditions of maximum respiration induced with either ADP or carbonyl cyanidep-trifluoromethoxyphenylhydrazone,α-ketoglutarate supported the highest rate of H2O2production. In the absence of ADP or in the presence of rotenone, H2O2production rates correlated with the reduction level of mitochondrial NADPH with various substrates, with the exception of α-ketoglutarate. Isolated mitochondrial α-ketoglutarate dehydrogenase (KGDHC) and pyruvate dehydrogenase (PDHC) complexes produced superoxide and H2O2. NAD+inhibited ROS production by the isolated enzymes and by permeabilized mitochondria. We also measured H2O2production by brain mitochondria isolated from heterozygous knock-out mice deficient in dihydrolipoyl dehydrogenase (Dld). Although this enzyme is a part of both KGDHC and PDHC, there was greater impairment of KGDHC activity in Dld-deficient mitochondria. These mitochondria also produced significantly less H2O2than mitochondria isolated from their littermate wild-type mice. The data strongly indicate that KGDHC is a primary site of ROS production in normally functioning mitochondria.
Extreme Stretch Growth of Integrated Axons
Authors: Pfister Bryan J. , Iwata Akira , Meaney David F. , Smith Douglas H.
Published: September 2004

Large animals can undergo enormous growth during development, suggesting that axons in nerves and white matter tracts rapidly expand as well. Because integrated axons have no growth cones to extend from, it has been postulated that mechanical forces may stimulate axon elongation matching the growth of the animal. However, this distinct form of rapid and sustained growth of integrated axons has never been demonstrated. Here, we used a microstepper motor system to evaluate the effects of escalating rates of stretch on integrated axon tracts over days to weeks in culture. We found that axon tracts could be stretch grown at rates of 8 mm/d and reach lengths of 10 cm without disconnection. Despite dynamic and long-term elongation, stretched axons increased in caliber by 35%, while the morphology and density of cytoskeletal constituents and organelles were maintained. These data provide the first evidence that mechanical stimuli can induce extreme “stretch growth” of integrated axon tracts, far exceeding any previously observed limits of axon growth.
Early N-Terminal Changes and Caspase-6 Cleavage of Tau in Alzheimer's Disease
Authors: Horowitz Peleg M. , Patterson Kristina R. , Guillozet-Bongaarts Angela L. , Reynolds Matthew R. , Carroll Christopher A. , Weintraub Susan T. , Bennett David A. , Cryns Vincent L. , Berry Robert W. , Binder Lester I.
Published: September 2004

Alzheimer's disease (AD) is a progressive amnestic dementia that involves post-translational hyperphosphorylation, enzymatic cleavage, and conformational alterations of the microtubule-associated protein tau. The truncation state of tau influences many of its pathologic characteristics, including its ability to assume AD-related conformations and to assemble into filaments. Cleavage also appears to be an important marker in AD progression. Although C-terminal truncation of tau at D421 has recently been attributed to the apoptotic enzyme caspase-3, N-terminal processing of the protein remains mostly uncharacterized. Here, we report immunohistochemical staining in a cohort of 35 cases ranging from noncognitively impaired to early AD with a panel of three N-terminal anti-tau antibodies: Tau-12, 5A6, and 9G3-pY18. Of these three, the phosphorylation-independent epitope of 5A6 was the earliest to emerge in the pathological lesions of tau, followed by the appearance of the Tau-12 epitope. The unmasking of the Tau-12 epitope in more mature 5A6-positive tangles was not correlated with tau phosphorylation at tyrosine 18 (9G3-pY18). Still, later in the course of tangle evolution, the extreme N terminus of tau was lost, correlating temporally with the appearance of a C-terminal caspase-truncated epitope lacking residues 422-441. In addition, caspase-6 cleaved the N terminus of tauin vitro, preventing immunoreactivity with both Tau-12 and 5A6. Mass spectrometry confirmed that thein vitrocaspase-6 truncation site is D13, a semicanonical and hitherto undescribed caspase cleavage site in tau. Collectively, these results suggest a role for caspase-6 and N-terminal truncation of tau during neurofibrillary tangle evolution and the progression of Alzheimer's disease.
Genetically Decreased Spinal Cord Copper Concentration Prolongs Life in a Transgenic Mouse Model of Amyotrophic Lateral Sclerosis
Authors: Kiaei Mahmoud , Bush Ashley I. , Morrison Brett M. , Morrison John H. , Cherny Robert A. , Volitakis Irene , Beal M. Flint , Gordon Jon W.
Published: September 2004

Mutations in the Cu/Zn superoxide dismutase (SOD1) gene cause familial amyotrophic lateral sclerosis (FALS) by gain of an aberrant function that is not yet well understood. The role of Cu2+in mediating the toxicity of mutant SOD1 has been earnestly contested. We tested thein vivoeffects of genetically induced copper deprivation on the ALS phenotype of transgenic mice expressing G86R mutant mouse SOD1, a protein that fails to incorporate Cu2+in its active site. Genetically copper-deficient SOD1G86Rtransgenic mice were produced by mating SOD1G86Rmales to female carriers of the X-linked mottled/brindled (Mobr) mutation. We found that the Mobr allele causes a severe (∼60%) depletion of spinal cord copper levels; however, despite the burden of double genetic lesions, it lengthens the lives of SOD1G86Rtransgenic mice by 9%. These findings provide evidence supporting a role for copper in the pathogenesis of FALS linked to SOD1 mutations.
Hypothermia-Associated Loss of Dendritic Spines
Authors: Roelandse Martijn , Matus Andrew
Published: September 2004

Mechanisms of synaptic plasticity in CNS circuits are commonly investigated usingin vitropreparations such as brain slices or slice culture. During their preparation, slices are exposed to low temperatures, and electrophysiological measurements are sometimes made below physiological temperature. Because dendritic spines, which occur at the majority of excitatory synapses, are morphologically plastic, we investigated the influence of reduced temperature on their morphology and plasticity using live cell imaging of hippocampal slices from transgenic mice expressing a green fluorescent protein-based neuronal surface marker and electron microscopy of adult brain slices. Our data show that dendritic spines are highly sensitive to reduced temperature with rapid loss of actin-based motility followed at longer times by reversible loss of the entire spine structure. Thus, reduced temperature significantly affects synaptic morphology, which is in turn known to influence several key aspects of synaptic transmission. Evidence that hypothermia potentiates anesthesia and is associated with spine loss in hibernating animals further suggests that spine morphology may have a widespread influence on brain function.
Attentional Modulation of Motion Integration of Individual Neurons in the Middle Temporal Visual Area
Authors: Cook Erik P. , Maunsell John H. R.
Published: September 2004

We examined how spatially directed attention affected the integration of motion in neurons of the middle temporal (MT) area of visual cortex. We recorded from single MT neurons while monkeys performed a motion detection task under two attentional states. Using 0% coherent random dot motion, we estimated the optimal linear transfer function (or kernel) between the global motion and the neuronal response. This linear kernel filtered the random dot motion across direction, speed, and time. Slightly less than one-half of the neurons produced reasonably well defined kernels that also tended to account for both the directional selectivity and responses to coherent motion of different strengths. This subpopulation of cells had faster, more transient, and more robust responses to visual stimuli than neurons with kernels that did not contain well defined regions of integration. For those neurons that had large attentional modulation and produced well defined kernels, we found attention scaled the temporal profile of the transfer function with no appreciable shift in time or change in shape. Thus, for MT neurons described by a linear transfer function, attention produced a multiplicative scaling of the temporal integration window.
Reversible Tenso‐Resistance and Piezo‐Resistance Effects in Conductive Polymer‐Carbon Nanocomposites
Authors: Knite M. , Teteris V. , Kiploka A. , Klemenoks I.
Published: September 2004

Recently efforts have been made to obtain active polymer‐elektrically conductive particle composites the conductivity of which would be strongly dependent on external thermodynamic parameters – pressure, temperature, and other. New interesting properties are expected in case the polymer composite contains dispersed nano‐size conducting particles. The present study is focused on examining electrical resistance vs tensile strain and pressure of polyisoprene‐corbon nanocomposites near the percolation threshold to find the best composition for sensor applications.
Gas Chromatographic — Mass Spectrometric Determination of Phenylacetic Acid in Human Blood
Authors: Mangani Giovanna , Canestrari Franco , Berloni Arnaldo , Maione Michela , Pagliarani Silvia , Mangani Filippo
Published: September 2004

Phenyl acetic acid, a metabolite of 2—phenyl ethylamine, acts as a neuromodulator in the nigrostriatal dopaminergic pathway neuromodulator stimulating the release of dopamine. The evaluation of phenyl acetic acid concentration in the biological fluid reflects phenyl ethylamine levels thus allowing the assessment of the modulatory role of this endogenous substance. Changes in biological fluids levels of 2—phenylethylamine and/or in its metabolite have been reported in affective disorders, such as depression and schizophrenia. Recently, the occurrence of the “attention deficit hyperactivity syndrome” has been frequently reported in childhood population and involvement of dopaminergic dysfunction in this disease has been suspected. A fast, reliable and reproducible method for the determination of phenyl acetic acid in human blood, is therefore needed in order to have a screening tool for monitoring both healthy childhood population and suspected “attention deficit hyperactivity syndrome” patients. The gas chromatographicmass spectrometric method here described makes use of a deuterated internal standard in order to overcome problems related to the lack of reproducibility often encountered when a derivatization step is performed.
Improved Analysis of Polycyclic Aromatic Hydrocarbons in Atmospheric Particulate Matter by HPLC—Fluorescence
Authors: Bacaloni Alessandro , Cafaro Claudia , de Giorgi Loretta , Ruocco Roberta , Zoccolillo Lelio
Published: September 2004

An improved method is reported for determination of Polycyclic Aromatic Hydrocarbons (PAHs) in atmospheric particulate matter by HPLC—FLD. The sampling step (air volume collected during each sampling period varies in the range 10≑13 m3) is carried out by means of a mediumflow pumping system (15 L min—1) on a glass fiber filter (47 mm diameter) placed as collecting substrate in the samplingcassette. After sampling, the filter is extracted with 3 ml of acetonitrile in an ultrasonic bath for 30 minutes. As for extraction of PAHs from loaded filters a new criterion here is proposed to evaluate the recovery efficiency of PAHs from the sample, instead of the usual spiking method of standard solution. The extract was then reduced to 100 μL and analysed by HPLC—FLD on line spectra system. The method is rapid (about one hour for extraction and analysis), reproducible and enables to measure with good accuracy the atmospheric concentration of benzo(b) fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), benzo(ghi) perylene (BghiP), carcinogenic compounds always present in the urban airborne particulate matter. So it is useful for routine pollution studies and suitable to substitute the official method used now. Monthly average air concentrations, for the four PAHs above mentioned, measured in Rome from July 2001 to June 2002, are reported.
Biomass accumulation and clogging in trickle‐bed bioreactors
Authors: Iliuta Ion , Larachi Faïçal
Published: September 2004

Excessive biomass formation in two‐phase flow trickle‐bed bioreactors induces clogging and leads to the progressive obstruction of the bed that is accompanied with a buildup in pressure drop and flow channeling. Currently, physical models linking the two‐phase flow to the space‐time evolution of biological clogging are virtually nonexistent. An attempt has been made with this contribution to fill in this gap by developing a unidirectional dynamic multiphase flow model based on the volume‐average mass, momentum, and species balance equations. Phenol biodegradation by Pseudomonas putida as the predominant species immobilized on activated carbon was chosen as a case study to illustrate the consequences of formation of excessive amounts of biomass. Furthermore, in developing the transient model, the following basic processes were assumed to occur and have been accounted for in the mathematical model: oxygen transport from gas into liquid bulks, phenol, and oxygen transport from the liquid phase to the biofilm surface, simultaneous diffusion and reaction of phenol and oxygen within biofilm, as well as their simultaneous diffusion and adsorption within the porous supporting particles. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2541–2551, 2004
A simultaneous method for two‐ and three‐liquid–phase stability determination
Authors: Guo Minqiang , Wang Shuqing , Repke Jens‐Uwe , Wozny Günter
Published: September 2004

The methods for multiphase stability determination are generally based on Gibbs free energy minimization. However, a novel and efficient method is proposed in this work for one‐, two‐, and particularly three‐liquid‐phase stability identification in ternary mixtures. The method is designated the extended general line‐length (EGL) method, which is based on our previous GL method. Both the EGL and GL methods are equation‐solving approaches. The EGL method is easy to understand and can be performed fast. Only parameters of the thermodynamic models, such as UNIQUAC and NRTL, are required for the stability determination. The thermodynamic model applied does not influence the rapidness and validity of the EGL method. Graphical techniques and simultaneous computation are adopted in this method. Its applicability and efficiency are exemplified by three typical examples. For each example, three different phase configurations, consisting of one‐, two‐, and up to a three‐liquid phase, are tested. The results show that the EGL method can be used for the determination of multiphase stability in all liquid‐phase configurations of ternary systems. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2571–2582, 2004
Skeletal age, dental age, and the maturation of KNM‐WT 15000
Authors: Smith Shelley L.
Published: September 2004

The skeleton of theHomo erectusboy from West Lake Turkana, Kenya (KNM‐WT 15000), is remarkably complete, and this individual has thus provided a case study for several researchers examiningHomo erectusgrowth. Using data from a longitudinal study of Montreal French‐Canadian children, it is shown that while dental and skeletal ages match reasonably well at the level of a sample of children, individuals can display differences between skeletal and dental ages of 2 years or more. Furthermore, the relationship between these two markers may change over time in individual children. It is also possible to find children with patterns of dental maturation similar to KNM‐WT 15000's pattern in the Montreal sample. Therefore, neither the discrepancy between skeletal age and dental age alone nor the pattern of dental maturation as assessed by dental stages precludes a human‐like pattern of growth, including an adolescent growth spurt, for this individual. Some indicators (e.g., estimated body size for predicted age, and enamel formation) do suggest possible growth‐patterning differences from modern humans, and therefore earlier maturation is a reasonable hypothesis, but caution is warranted, given the large degree of modern human variation in developmental markers and the inherent uncertainty in precise estimation of KNM‐WT 15000's maturational parameters. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Estimation of the most likely number of individuals from commingled human skeletal remains
Authors: Adams Bradley J. , Konigsberg Lyle W.
Published: September 2004

This study examines quantification techniques applicable to human skeletal remains, and in particular the Lincoln index (LI), the minimum number of individuals (MNI), and what we refer to as the most likely number of individuals (MLNI), which is a modification of the LI by Chapman ([1951] Univ. Calif. Publ. Stat. 1:131–159). As part of the study, a test of pair‐matching between commingled homologous elements, e.g., right and left femora, was performed based on gross morphology. The results show that pair‐matching can be accurately performed, and that the MLNI is a useful technique for dealing with well‐preserved commingled remains recovered from archaeological excavations and/or forensic investigations. Our results show that it is potentially misleading to draw population conclusions based on the MNI, except in instances where recovery is near 100%. The MLNI was found to be the best method to compensate for the potential underestimates of the MNI and potential bias in the original LI estimates resulting from small sample sizes. We demonstrate the use of MLNI in estimating the number of individuals from Lodge 21 at the Larson site, a late protohistoric structure at which the inhabitants were massacred and subsequently had their skeletal elements commingled by further taphonomic processes. We also show how to calculate estimates and standard errors for the recovery probabilities of skeletal elements. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Crystalline morphology and isothermal crystallization kinetics of poly(ethylene terephthalate)/clay nanocomposites
Authors: Wan Tong , Chen Ling , Chua Yang Choo , Lu Xuehong
Published: September 2004

A poly(ethylene terephthalate) (PET)/montmorillonite clay nanocomposite was synthesized via in situ polymerization. Microscopic studies revealed that in an isothermal crystallization process, some crystallites in the nanocomposite initially were rod‐shaped and later exhibited three‐dimensional growth. The crystallites in the nanocomposite were irregularly shaped, rather than spherulitic, being interlocked together without clear boundaries, and they were much smaller than those of neat PET. With Avrami analysis, the isothermal crystallization kinetic parameters (the Avrami exponent and constant) were obtained. The rate constants for the nanocomposite demonstrated that clay could greatly increase the crystallization rate of PET. The results for the Avrami exponent were consistent with the observation of the rodlike crystallites in the PET/clay nanocomposite during the initial stage. Wide‐angle X‐ray scattering and Fourier transform infrared studies showed that, in comparison with neat PET, the crystal lattice parameters and crystallinity of the nanocomposite did not change significantly, whereas more defects may have been present in the crystalline regions of the nanocomposite because of the presence of the clay. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1381–1388, 2004
Effects of polymeric emulsifiers on the properties of acrylic emulsion pressure‐sensitive adhesives
Authors: Park Myung‐Chul , Lee Myung Cheon
Published: September 2004

A series of polymeric emulsifiers was polymerized with 2‐ethylhexyl acrylate, butyl acrylate, and acrylic acid. The polymeric emulsifiers were used to make emulsion copolymers of 2‐ethylhexyl acrylate, butyl acrylate, and acrylic acid. The average particle size of the synthesized emulsions was around 145 nm and the size distribution was very narrow. Also, the emulsions showed good freeze–thaw stability and adhesion properties. The peel strength and holding power of the emulsions were investigated by changing the composition and molecular weight of the polymeric emulsifier. The results show that the peel strength exhibits a maximum at particular molecular weight and acrylic acid content of the polymeric emulsifier, while the holding power increases with molecular weight. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1456–1460, 2004
Stem and bunch banana fibers from cultivation wastes: Effect of treatments on physico‐chemical behavior
Authors: Gañán Piedad , Cruz Javier , Garbizu Saioa , Arbelaiz Aitor , Mondragon Iñaki
Published: September 2004

Much research related to the use of natural fibers in polymeric matrix composites has been developed. The presence of OH groups in the chemical components of the natural fibers generates an important hydrophylic tendency that produces adhesion lacks with hydrophobic polymeric matrices. In this work natural fiber bundles mechanically extracted from both stem and bunch of cultivation banana wastes have been modified by both alkalization and silanization treatments. To evaluate the changes introduced by treatments on the chemical structure of fibers, Fourier‐transform infrared spectrophotometry has been employed. The evaluation of advancing dynamic contact angles along with the determination of total surface free energy by using the Owens–Wendt method indicate that the treatments allow reduction of their hydrophilic tendency by alterations on the physicochemical characteristics of the fibers. This behavior is confirmed by the reduction of moisture uptake, analyzed by thermogravimetric analysis. Small differences on noncellulosic components of stem and bunch fiber bundles have been found. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1489–1495, 2004