bluuebunny/crossref_metadata_2025 huggingface dataset:
Afferent Input Modulates Neurotrophins and Synaptic Plasticity in the Spinal Cord
Authors: Gómez-Pinilla Fernando , Ying Zhe , Roy Roland R. , Hodgson John , Edgerton V. Reggie
Published: November 2004

The effects of eliminating or decreasing neuromuscular activity on the expression of neurotrophins and associated molecules in the spinal cord and subsequent effects on spinal cord plasticity were determined. Spinal cord isolation (SI), which eliminates any supraspinal and peripheral monosynaptic input to the lumbar region but maintains the motoneuron-muscle connectivity, decreased the levels of brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) mRNA and protein in the isolated segments. Synapsin I, an important mediator for the effects of BDNF on synaptic plasticity, also was lower in the lumbar region of SI rats. In contrast, the levels of BDNF, synapsin, and growth-associated protein (GAP-43) were increased in the cervical spinal cord enlargement rostral to the isolated region, most likely reflecting an increased use of the forelimbs in the SI rats. GAP-43 levels were also increased in the lumbar spinal cord region, probably associated with compensatory mechanisms related to the deafferentation. In a separate set of experiments, the soleus muscle was paralyzed unilaterally via intramuscular botulinum toxin type A (BTX-A) injection to determine the effects of reducing the propioceptive input, of this normally highly active muscle on neurotrophin expression in the spinal cord. BDNF and synapsin I mRNAs were lower and NT-3 levels were higher in the lumbar hemicord ipsilateral to the BTX-A injection. Combined, these results indicate that the level of supraspinal and muscle afferent input plays an important role in modulating the levels of BDNF and NT-3 in the spinal cord.
On extended type I generalized logistic distribution
Authors: Olapade A. K.
Published: November 2004

We consider a form of generalized logistic distribution which is
called extended type I generalized logistic distribution.
Some theorems that relate the distribution to some other
statistical distributions are established. A possible application
of one of the theorems is included.
Lower and upper bounds of shortest paths in reachability graphs
Authors: Mishra P. K.
Published: November 2004

We prove the following property for safe marked
graphs, safe conflict‐free Petri nets, and live and safe extended
free‐choice Petri nets. We prove the following three results.
If the Petri net is a marked graph, then the length of the
shortest path is at most
(|T| − 1) · |T|/2.
If the Petri net is conflict free, then the length
of the shortest path is at most
(|T| + 1) · |T|/2.
If the petrinet is live and extended free choice, then
the length
of the shortest path is at most
|T| · |T + 1| · |T + 2|/6,
where T is the set of transitions of the net.
BACE1 and Presenilin: Two Unusual Aspartyl Proteases Involved in Alzheimer’s Disease
Authors: Dominguez Diana-Ines , Hartmann Dieter , De Strooper Bart
Published: November 2004

Two enzymatic activities are required to generate the pathogenic β-amyloid (Aβ) peptide that accumulates in the brain of Alzheimer’s disease patients. Both activities are carried out by two unusual aspartyl proteases known as β- and γ-secretase. Their therapeutic inhibition appears, therefore, a promising strategy to treat the disease. Transgenic mouse models in which the genes encoding the secretases have been ablated offer an invaluable tool, on the one hand, to gain more insights into the biological function of these proteases and, on the other hand, to predict the consequences that might be associated with enzyme inhibition in vivo.
Voxel-Based Morphometry in Tau-Positive and Tau-Negative Frontotemporal Lobar Degenerations
Authors: Whitwell Jennifer L. , Warren Jason D. , Josephs Keith A. , Godbolt Alison K. , Revesz Tamas , Fox Nick C. , Rossor Martin N.
Published: November 2004

Background: The identification of specific, diagnostically useful predictors of protein dysfunction in the frontotemporal lobar degenerations (FTLD) is a problem of great clinical and biological interest. Correlations between regional patterns of tissue loss and specific proteinopathies have not been established. Objective: Specific brain imaging correlates of protein tau dysfunction were sought using voxel-based morphometry in FTLD subgroups with and without tau pathology. Methods: Seventeen patients with pathologically or genetically confirmed diagnoses of FTLD who had undergone volumetric brain magnetic resonance imaging (MRI) were identified retrospectively and tau-positive (n = 9) and tau-negative (n = 8) subgroups were defined. MRI data were compared with healthy age- and sex-matched controls using voxel-based morphometry implemented in a statistical parametric mapping software package. Results: Compared with controls, tau-positive and tau-negative subgroups had extensive common areas of regional brain atrophy predominantly affecting the frontal and anterior temporal lobes. No specific brain imaging features were identified for either subgroup. Conclusion: Patterns of frontotemporal atrophy do not predict the presence or absence of tau pathology; conversely, different immunohistochemical profiles are associated with similar patterns of regional vulnerability to neuronal loss in FTLD.
A Retrospective Analysis of the Role of Transvaginal Sonography in the Evaluation of Patients with Abnormal Postmenopausal Bleeding
Authors: Gibbs Vivien , Henson John , Hawkins Karen
Published: November 2004

Post-menopausal bleeding is an increasingly common reason for referral to a gynaecology department. Whilst the bleeding could be attributable to a number of different reasons, these patients are more at risk of endometrial cancer than pre-menopausal women. As it is not possible to exclude endometrial carcinoma on clinical assessment alone, further investigative techniques are required. The role of diagnostic ultrasound in the evaluation of these patients varies within different hospitals; however, it is generally accepted that ultrasound is an appropriate first-line procedure to exclude the presence of endometrial pathology. This paper looks at 103 patients undergoing transvaginal ultrasound, hysteroscopy and biopsy investigations. The aim of the study was to correlate the hysteroscopy and biopsy findings with the appearances reported following the ultrasound scan, in order to determine the sensitivity and specificity of transvaginal scanning in detecting endometrial pathology.
Waveband Selection for Determination of Nitrate in Soil Using Mid-Infrared Attenuated Total Reflectance Spectroscopy
Authors: Linker Raphael
Published: November 2004

This paper investigates the possibility of determining nitrate concentration in soil pastes using spectral absorbance at several fixed wavebands. A three-step procedure for determining the most appropriate wavebands, as well as their width, is described. This procedure is applied to a dataset that includes eleven soils with various nitrate concentrations ranging from 0 to approximately 150 mg [N]/kg [dry soil]. The results show that nitrate concentration can be determined quite acceptably using only four 12 cm−1 wide wavebands, centered at 1280, 1330, 1379, and 1430 cm−1. The prediction errors range from approximately 1.5 to 14.0 mg [N]/kg [dry soil], depending on soil composition and moisture content, with the lighter and more vulnerable (pollution-wise) soils having errors inferior to 10 mg [N]/kg [dry soil]. These results are similar to results obtained by applying partial least square to the ‘continuous' spectrum, and indicate that the development of a soil nitrate attenuated total reflectance (ATR) sensor based on a few fixed mid-infrared (MIR) wavebands could be considered.
Forensic Analysis of Poly(Ethylene Terephthalate) Fibers by Infrared Spectroscopy
Authors: Causin Valerio , Marega Carla , Guzzini Giuseppe , Marigo Antonio
Published: November 2004

Poly(ethylene terephthalate) (PET) is one of the most commonly employed polymers in the textile industry. Its relevance as a source of evidence in the reconstruction of criminal cases is nevertheless very limited because the properties and morphologies of fibers from different producers tend to be very similar. By integrating bands, obtained on single fibers by infrared (IR) microscopy, associated with trans and gauche conformation and to the O–H end-groups of the molecules, a method is proposed that can discriminate otherwise similar PET fibers. The absorbancies at 1370 and at 846 cm−1 relative, respectively, to the gauche and trans conformation, were measured and ratioed. The end-group content was evaluated by ratioing the absorbancies of the signals at 3440 and at 874 cm−1. Relative standard deviation (R.S.D.) was 1% for repetitive analyses on the same location of the same single fiber. Precision was reduced if the ratios were measured along the length of a single fiber (R.S.D. = 3%) and even further when different fibers of the same sample were examined (R.S.D. varied from 2 to 10%). This simple method can greatly enhance the evidential value of PET fibers by subclassifying them, thus helping the Court to better assess their significance.
Modification of Derivatives for Resolution Enhancement of Bands in Overlapped Spectra
Authors: Buslov Dmitrii K.
Published: November 2004

A method for obtaining modified derivatives based on the multiplication of the Fourier image of a normal derivative of degree n by the function (– iSign( x)) n has been considered. The thus-obtained modified derivatives of even, odd, and fractional degrees of symmetric functions are also even functions, which permits one to use them for obtaining spectra with a better resolution of individual bands. Also, the use of derivatives of various degrees makes it possible to considerably widen the set of functions suitable for resolving individual bands in overlapped spectra. The results of the application of modified derivatives to synthetic and experimental spectra have been considered. The conclusion has been drawn that practical application of such derivatives permits more flexible variation of the resolution in the resulting spectrum compared to the normal derivatives of only even orders.
Real-Time Monitoring of High-Temperature Corrosion in Stainless Steels by Open-Path Laser-Induced Plasma Spectrometry
Authors: García P. L. , Vadillo J. M. , Laserna J. J.
Published: November 2004

Open-path laser-induced plasma spectrometry (OP-LIPS) represents an appealing alternative for the real-time monitoring of high-temperature processes due to its inherent non-invasive and remote capabilities. In this work, stainless steel samples have been analyzed at 10 meters from the laser source. The effect of the high-temperature conditions to the protective anti-corrosion layer have been analyzed, as well as additional factors such as the type of steel and the exposure time. The number of pulses required to ablate the alteration layer has been found to follow a linear relationship with the square root of the exposure time, in excellent agreement with the off-line thermogravimetric measurements described in the literature.
Mid-Ultraviolet Light-Emitting Diode Detects Dipicolinic Acid
Authors: Li Qingyang , Dasgupta Purnendu K. , Temkin Henryk , Crawford M. H. , Fischer A. J. , Allerman A. A. , Bogart K. H. A. , Lee S. R.
Published: November 2004

Dipicolinic acid (DPA, 2,6-pyridinedicarboxylic acid) is a substance uniquely present in bacterial spores such as that from anthrax ( B. anthracis). It is known that DPA can be detected by the long-lived fluorescence of its terbium chelate; the best limit of detection (LOD) reported thus far using a large benchtop gated fluorescence instrument using a pulsed Xe lamp is 2 nM. We use a novel AlGaN light-emitting diode (LED) fabricated on a sapphire substrate that has peak emission at 291 nm. Although the overlap of the emission band of this LED with the absorption band of Tb-DPA (λmax doublet: 273, 279 nm) is not ideal, we demonstrate that a compact detector based on this LED and an off-the-shelf gated photodetection module can provide an LOD of 0.4 nM, thus providing a basis for convenient early warning detectors.
Non-Resonant Multiphoton Photoacoustic Spectroscopy for Noninvasive Subsurface Chemical Diagnostics
Authors: Chandrasekharan Nirmala , Gonzales Benjamin , Cullum Brian M.
Published: November 2004

This paper describes the development and validation of a novel noninvasive spectroscopic subsurface chemical detection technique, non-resonant multiphoton photoacoustic spectroscopy (NMPPAS). In this technique, non-resonant multiphoton excitation is used to provide subsurface excitation of chemical constituents in a sample followed by the subsequent detection of an acoustic signal using a piezoelectric transducer. Because NMPPAS relies on non-radiative relaxation of the absorbing species, it is capable of monitoring both fluorescent and non-fluorescent species. Moreover, since the majority of the energy imparted to most molecules upon the absorption of light is released through non-radiative pathways, sensitive measurements of even fluorescent molecules can be performed. In this paper, demonstration of proof-of-principle of this novel technique has been shown using test samples of common fluorescent dyes and biomarkers including rhodamine 6G, tryptophan, and NADH in solution and gelatin tissue phantoms. From these studies, it was found that detection limits of these chromophores are in the subnanomolar concentration regime. In addition, preliminary results on excised tumor and healthy tissue samples have demonstrated significant differences between the tumorous and non-tumorous tissues at 740 nm and 950 nm wavelengths. From this work, it was found that NMPPAS has a great deal of potential for subsurface chemical diagnostics in the field of biomedical research.
Multiple Time Scales of Adaptation in Auditory Cortex Neurons
Authors: Ulanovsky Nachum , Las Liora , Farkas Dina , Nelken Israel
Published: November 2004

Neurons in primary auditory cortex (A1) of cats show strong stimulus-specific adaptation (SSA). In probabilistic settings, in which one stimulus is common and another is rare, responses to common sounds adapt more strongly than responses to rare sounds. This SSA could be a correlate of auditory sensory memory at the level of single A1 neurons. Here we studied adaptation in A1 neurons, using three different probabilistic designs. We showed that SSA has several time scales concurrently, spanning many orders of magnitude, from hundreds of milliseconds to tens of seconds. Similar time scales are known for the auditory memory span of humans, as measured both psychophysically and using evoked potentials. A simple model, with linear dependence on both short-term and long-term stimulus history, provided a good fit to A1 responses. Auditory thalamus neurons did not show SSA, and their responses were poorly fitted by the same model. In addition, SSA increased the proportion of failures in the responses of A1 neurons to the adapting stimulus. Finally, SSA caused a bias in the neuronal responses to unbiased stimuli, enhancing the responses to eccentric stimuli. Therefore, we propose that a major function of SSA in A1 neurons is to encode auditory sensory memory on multiple time scales. This SSA might play a role in stream segregation and in binding of auditory objects over many time scales, a property that is crucial for processing of natural auditory scenes in cats and of speech and music in humans.
Chronic Back Pain Is Associated with Decreased Prefrontal and Thalamic Gray Matter Density
Authors: Apkarian A. Vania , Sosa Yamaya , Sonty Sreepadma , Levy Robert M. , Harden R. Norman , Parrish Todd B. , Gitelman Darren R.
Published: November 2004

The role of the brain in chronic pain conditions remains speculative. We compared brain morphology of 26 chronic back pain (CBP) patients to matched control subjects, using magnetic resonance imaging brain scan data and automated analysis techniques. CBP patients were divided into neuropathic, exhibiting pain because of sciatic nerve damage, and non-neuropathic groups. Pain-related characteristics were correlated to morphometric measures. Neocortical gray matter volume was compared after skull normalization. Patients with CBP showed 5-11% less neocortical gray matter volume than control subjects. The magnitude of this decrease is equivalent to the gray matter volume lost in 10-20 years of normal aging. The decreased volume was related to pain duration, indicating a 1.3 cm3loss of gray matter for every year of chronic pain. Regional gray matter density in 17 CBP patients was compared with matched controls using voxel-based morphometry and nonparametric statistics. Gray matter density was reduced in bilateral dorsolateral prefrontal cortex and right thalamus and was strongly related to pain characteristics in a pattern distinct for neuropathic and non-neuropathic CBP. Our results imply that CBP is accompanied by brain atrophy and suggest that the pathophysiology of chronic pain includes thalamocortical processes.
Memory Consolidation and Reconsolidation in the Rat Pup Require Protein Synthesis
Authors: Gruest Nadège , Richer Paulette , Hars Bernard
Published: November 2004

Little is known about the ontogenesis of memory, whether it appears with its full characteristics or whether they emerge progressively with development. In the adult, basic characteristics of memory processing are consolidation of memory after acquisition and reconsolidation after retrieval. Here, using a conditioned aversion paradigm and postlearning or postreactivation injection of a protein synthesis inhibitor, we show that memory acquired by rat pups as early as postnatal day 3 requires time-dependent protein synthesis after both learning and reactivation. These results present the first evidence suggesting that consolidation and reconsolidation are original properties of memory function.
PHCCC, a Specific Enhancer of Type 4 Metabotropic Glutamate Receptors, Reduces Proliferation and Promotes Differentiation of Cerebellar Granule Cell Neuroprecursors
Authors: Canudas A. M. , Di Giorgi-Gerevini V. , Iacovelli L. , Nano G. , D'Onofrio M. , Arcella A. , Giangaspero F. , Busceti C. , Ricci-Vitiani L. , Battaglia G. , Nicoletti F. , Melchiorri D.
Published: November 2004

Exposure of immature rat cerebellar granule cell cultures to the type 4 metabotropic glutamate (mGlu4) receptor enhancerN-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC) reduced [3H]thymidine incorporation. Its action was sensitive to the growth conditions and was attenuated by two mGlu4 receptor antagonists. An antiproliferative action of PHCCC was also seen in cultures from wild-type, but not mGlu4, knock-out mice. At least in rat cultures, PHCCC was not neurotoxic and enhanced neuritogenesis. Although PHCCC reduced the increase in cAMP formation and phospho-AKT levels induced by forskolin, none of these transduction pathways significantly contributed to the reduction of [3H]thymidine incorporation. Interestingly, PHCCC reduced the expression of Gli-1, a transcription factor that mediates the mitogenic action of Sonic hedgehog. Finally, we treated newborn rats with PHCCC either intracerebrally (infusion of 5 nmol/2 μl in the cerebellar region once every other day) or systemically (5 mg/kg, i.p., once daily) from postnatal days 3-9. Local infusion of PHCCC induced substantial changes in the morphology of the developing cerebellum. In contrast, systemic injection of PHCCC induced only morphological abnormalities of the cerebellar lobule V, which became visible 11 d after the end of the treatment. These data suggest that mGlu4 receptors are involved in the regulation of cerebellar development.
Evolutionary Mechanisms of Fear and Anxiety
Authors: Hofmann Stefan G. , Moscovitch David A. , Heinrichs Nina
Published: November 2004

This article examines evolutionary mechanisms in human fear and anxiety, with a particular focus on specific phobias and social phobia. The contribution of evolutionary factors to the development of specific phobias has led to refinements and modifications of earlier conditioning theories. Evolutionary mechanisms further affect cognitive factors of fear and anxiety, such as self-related processes and social comparisons, as in the case of social phobia. Although not without controversy, an evolutionary theory of human fear and anxiety adds a unique perspective that could potentially lead to improved psychopathology models, nosological systems, and treatment strategies for anxiety disorders.
The Relationship of Maladaptive Beliefs to Personality and Behavioral Adjustment Among Incarcerated Women
Authors: Loper Ann Booker
Published: November 2004

This study examined the relationship between schema domains (Young, 1999) and adjustment in a sample of female prison inmates (N= 116). Participants completed the Early Maladaptive Schema Questionnaire—Revised, the SCID-II Screen, the Brief Symptom Inventory, and the Prison Violence Inventory. Institutional records provided information concerning documented behavioral infractions. The Impaired Limits domain score, representing entitlement and poor self-control themes, was associated with screening scores for paranoid, antisocial, borderline, histrionic, and narcissistic personality disorders, as well as hostility symptoms, institutional misconduct, and self-reported violence perpetration and victimization. The Disconnection/ Rejection domain score was associated with a wide array of self-reported mental illness symptoms. A significant relationship between the Impaired Autonomy domain scale and dependent personality disorder (SCID-II Screen) was also observed. Results indicate that domains of belief are plausibly related to specific dysfunction in personality and behavioral adjustment. Results also suggest the potential benefit of using cognitive therapy with incarcerated women.
A Comparison of Pain Measures Used With Patients With Fibromyalgia
Authors: Bigatti Silvia M. , Cronan Terry A.
Published: November 2004

The objective of the present study was to evaluate instruments used to assess pain in patients with fibromyalgia (FMS). Participants were 602 patients with FMS. Pain was measured with five scales: a visual analog scale (VAS), the Pain Rating, Present Pain, and Number of Words Chosen Indexes from the McGill Pain Questionnaire; and intensity of pain obtained from a manual tender point exam. The VAS had the highest correlations with other measures of pain and with self-efficacy for pain, physical functioning, fatigue, and stiffness. The correlations between the VAS and fatigue and stiffness were significantly higher than those of other pain measures (p< .01). Our findings suggest that the easy-to-administer VAS may be the most useful measure of pain with patients with FMS.
Assessing Data Adequacy for Clinical Research: Reliability and Validity of a Surgical Database
Authors: Bezanson Judy L. , Strickland Ora L. , Kinney Marguerite R. , Weintraub William S.
Published: November 2004

As clinical databases are utilized more frequently for clinical research, it is essential that researchers assess the quality of databased information. While researchers have begun to report strategies to measure accuracy of databased information, knowledge remains limited. The purpose of this study was to assess the reliability and validity of databased information among selected study variables contained within a computerized coronary artery surgery clinical database using the written patient medical record as an external standard. Both reliability (N= 400) and validity (N= 100) samples were randomly selected from a databased sampling frame of 548 Medicare subjects who underwent coronary artery bypass grafting surgery in 1998. Reliability assessed by consistency rates were age (95%), race (94%), gender (99%), congestive heart failure (CHF) (60.5%), angina (91.5%), renal insufficiency (82%), hypertension (91.7%), diabetes mellitus (93.7%), chronic obstructive pulmonary disease (COPD) (75.5%), clinical status (97%), American Society of Anesthesiologists classification (99%), prior peripheral vascular surgery (15.5%), prior CABGS (99%), and duration of mechanical ventilation (87.5%). These percentages reflected a large portion of missing data for CHF, COPD, and prior peripheral vascular surgery. Validity assessed by sensitivity and specificity analyses were all greater than 80%. The majority of computerized databased information among selected study variables was the same information recorded in the written patient medical record. Using the same external standard to assess both reliability and validity was a significant limitation of this study, which resulted in the same measure of data adequacy by utilizing differing statistical methods.
Toxicity and chemistry of aspen wood leachate to aquatic life: Field study
Authors: Taylor Barry R. , Carmichael N. Bruce
Published: November 2004

A dark, toxic leachate has been observed around woodpiles of trembling aspen (Populus tremuloides Michx.) cut in winter for pulp or structural lumber. We measured production of leachate from 18 m3 of harvestable aspen logs stacked in an open field near Dawson Creek, British Columbia, Canada. The logpile began producing leachate during the first winter thaw and continued to do so for the duration of the two-year study (mean, 250 L/collection). Aspen leachate was characterized by dark color, acidic pH (5.0-6.5), elevated conductivity (200-500 μS/cm), high to very high biochemical oxygen demand (500-5,000 mg/L) and total organic carbon concentrations (500-2,000 mg/L), variable levels of phenolic compounds (2-27 mg/L), and low dissolved oxygen tensions (<2 mg/L). In tests with rainbow trout (Oncorhynchus mykiss), Daphnia magna, and luminescent bacteria, the leachate varied from weakly toxic (median lethal concentration, >10%) to very toxic (median lethal concentration, <1%). The volume of leachate generated by the logpile was correlated with total precipitation (rain or snow) since the last collection. Loads of chemical constituents or toxicity (lethal concentration × volume) in the leachate did not decline over the duration of the study. Less than 10% of the total mass of leachable material in the aspen logs was removed during two years of exposure.
Effects of ammonia on juvenile unionid mussels (Lampsilis cardium) in laboratory sediment toxicity tests
Authors: Newton Teresa J. , Allran John W. , O'Donnell Jonathan A. , Bartsch Michelle R. , Richardson William B.
Published: November 2004

Ammonia is a relatively toxic compound generated in water and sediments by heterotrophic bacteria and accumulates in sediments and pore water. Recent data suggest that unionid mussels are sensitive to un-ionized ammonia (NH3) relative to other organisms. Existing sediment exposure systems are not suitable for ammonia toxicity studies with juvenile unionids; thus, we modified a system to expose juveniles to ammonia that was continuously infused into sediments. This system maintained consistent concentrations of ammonia in pore water up to 10 d. Juvenile Lampsilis cardium mussels were exposed to NH3 in pore water in replicate 96-h and 10-d sediment toxicity tests. The 96-h median lethal concentrations (LC50s) were 127 and 165 μg NH3-N/L, and the 10-d LC50s were 93 and 140 μg NH3-N/L. The median effective concentrations (EC50s) (based on the proportion affected, including dead and inactive mussels) were 73 and 119 μg NH3-N/L in the 96-h tests and 71 and 99 μg NH3-N/L in the 10-d tests. Growth rate was substantially reduced at concentrations between 31 and 76 μg NH3-N/L. The lethality results (when expressed as total ammonia) are about one-half the acute national water quality criteria for total ammonia, suggesting that existing criteria may not protect juvenile unionids.
Stress status of gudgeon (Gobio gobio) from rivers in Switzerland with and without input of sewage treatment plant effluent
Authors: Faller Patrick , Kobler Bernd , Peter Armin , Sumpter John P. , Burkhardt-Holm Patricia
Published: November 2004

To assess the importance of sewage treatment plant effluents on fish health, we studied gudgeon in two rivers in the Swiss midlands (Canton Lucerne). Both rivers receive pollution from diffuse sources, while one also receives the effluent of a sewage treatment plant. Male and female gudgeon during and outside of the spawning season were compared with respect to reproductive parameters and health status across both rivers as well as upstream and downstream of the STP. Several biomarkers were studied, including cytochrome P4501A, 7-ethoxyresorufin-O-deethylase, plasma vitellogenin, ovotestis, lipid, liver histology, condition factor, gonadosomatic index, splenosomatic index, parasites of spleen and liver, population structure, and species diversity. Gudgeons of both rivers exhibited signs of a moderately impaired health status. By a stepwise backward analysis, the cytochrome P4501A content, the splenosomatic index, and the incidence of parasites in the liver were found to provide the best discrimination of the three sampling sites. Evidence of a significant elevation in response to the sewage treatment plant effluent was found neither in vitellogenin concentration nor in the ovotestis rate. While population structure was analyzed upstream and downstream of the sewage treatment plant, only gudgeons of the latter site revealed a disturbed population structure, most probably caused by a former nitrite discharge.
Integrating enzymatic responses to organic chemical exposure with total oxyradical absorbing capacity and dna damage in the european eel Anguilla anguilla
Authors: Regoli Francesco , Winston Gary W. , Gorbi Stefania , Frenzilli Giada , Nigro Marco , Corsi Ilaria , Focardi Silvano
Published: November 2004

In this work, susceptibility to oxidative stress was analyzed under laboratory conditions in the European eel Anguilla anguilla. Eels were treated with increasing concentrations of benchmark environmental pollutants, namely, benzo[a]pyrene ([BaP], at 0, 0.1, 1, 10, and 50 mg/kg), β-naphthoflavone ([BNF], at 0, 0.1, 1, 10, and 50 mg/kg), Arochlor® 1254 (at 0, 0.1, 1, 10, and 50 mg/kg), and 2,3,7,8-tetrachlorodibenzo p-dioxin ([TCDD], at 0, 0.01, 0.1, 1, and 2 μg/kg). The integral relationships were analyzed between induction of ethoxyresorufin O-deethylase (EROD) activity, its involvement in perturbing oxyradical metabolism, and the role of cytochrome P450 and/or oxidative stress in mediating genotoxic effects. To reveal whether the oxidative status in exposed organisms was altered as a result of chemical exposure, measurements of the main endogenous antioxidant defenses were integrated with the measurement of total oxyradical scavenging capacity (TOSC) toward peroxyl radicals and hydroxyl radicals (·OH). This approach permits discriminating the resistance of a tissue toward different forms of oxyradicals, thereby indicating a differential role for specific reactive oxygen species (ROS) in perturbing the balance between prooxidant and antioxidant mechanisms. All the analyzed chemicals promoted EROD induction (reflective of CYP1A) and altered either the levels or the activities of the antioxidants studied, which might be anticipated to exert alterations in oxyradical metabolism. Analysis of TOSC suggested the prevalence of metabolic oxidative pathways leading to the more reactive ·OH on exposure to the chemicals studied. Of these chemicals, enhanced EROD activity correlated with genotoxic damage only in the cases of the nonhalogenated hydrocarbons BaP and BNF. The highest degree of genotoxic damage was consistently observed in organisms in which the capacity to absorb or scavenge ·OH was lowest. These data suggests a general relationship between oxidative stress and loss of DNA integrity in juvenile eels exposed to the chemicals studied herein.
Exposure patterns of perfluorooctane sulfonate in aquatic invertebrates from the Western Scheldt estuary and the southern North Sea
Authors: Van de Vijver Kristin I. , Hoff Philippe T. , Van Dongen Walter , Esmans Eddy L. , Blust Ronny , De Coen Wim M.
Published: November 2004

Over the past decades little research has been conducted on the environmental behavior and effects of fluorinated organochemicals (FOCs). Recently it has been reported that perfluorooctane sulfonic acid (PFOS) is occurring worldwide. Little is known about the PFOS levels in organisms originating from the southern North Sea and the Western Scheldt estuary. In this study, we determined, for the first time, the PFOS-exposure levels in Crangon crangon, Carcinus maenas, and Asterias rubens from these ecosystems. Concentrations on a wet-weight basis in soft tissues of shrimp, crab, and starfish ranged from 19 to 520 ng/g, from 24 to 877 ng/g, and from 9 to 176 ng/g, respectively. These results show the existence of a PFOS pollution gradient in organisms along the Western Scheldt estuary, with the highest concentrations near Antwerp. The range of PFOS levels in shrimp and crab are slightly higher in coastal regions compared with sampling sites in open water. This study shows widespread distribution of PFOS in the Belgian and Dutch marine and estuarine environment at rather high concentrations.
Effect of declining toxicant concentrations on algal bioassay endpoints
Authors: Simpson Stuart L. , Roland Marie G. E. , Stauber Jenny L. , Batley Graeme E.
Published: November 2004

Sorption, degradation, volatilization, and uptake by test organisms cause concentrations of many toxicants to decline during toxicity testing. Despite the recognition of this occurring, nominal, measured initial or time-averaged concentrations are commonly used for the calculation of inhibitory or effect concentrations from toxicity test data. Because a premise of constant exposure is assumed but not met in these calculations, the toxicity of the test water may be significantly underestimated. Laboratory experiments using a 72-h algal growth inhibition bioassay and copper as a toxicant are used to demonstrate that calculated inhibitory concentrations will often be underestimated twofold if losses of copper occurring over the 72-h test duration are not considered. A simple model is presented for toxicant concentration decline and for the relationship between algal growth rate and toxicant concentration. This model is used to demonstrate the magnitude that calculated inhibitory concentrations may be underestimated if concentration declines are not considered for a series of different concentration decline scenarios. For a toxicant whose concentration declines exponentially to less than 5% of its original value within 36 h of a 72-h test, the inhibitory concentration is shown to be underestimated by a factor of 50.
A review and comparison of models for predicting dynamic chemical bioconcentration in fish
Authors: Barber M. Craig
Published: November 2004

Over the past 20 years, a variety of models have been developed to simulate the bioconcentration of hydrophobic organic chemicals by fish. These models differ not only in the processes they address but also in the way a given process is described. Processes described by these models include chemical diffusion through the gill's interlamellar water, epithelium, and lamellar blood plasma; advective chemical transport to and from the gill by ventilation and perfusion, respectively; and internal chemical deposition by thermodynamic partitioning to lipid and other organic phases. This article reviews the construction and associated assumptions of 10 of the most widely cited fish bioconcentration models. These models are then compared with respect to their ability to predict observed uptake and elimination rates using a common database for those model parameters that they have in common. Statistical analyses of observed and predicted exchange rates reveal that rates predicted by these models can be calibrated almost equally well to observed data. This fact is independent of how well any given model is able to predict observed exchange rates without calibration. The importance of gill exchange models and how they might by improved are also discussed.
Effect of pH and release® on two life stages of four anuran amphibians
Authors: Edginton Andrea N. , Stephenson Gerald R. , Sheridan Patrick M. , Thompson Dean G. , Boermans Herman J.
Published: November 2004

Using three native Canadian and one exotic anuran species, the interactive toxicity of pH and the forestry usedherbicide Release® (triclopyr [3,5,6-trichloro-2-pyridl-oxyacetic acid]) was assessed. Embryonic and larval (Gosner 25) stages of Rana pipiens, Rana clamitans, Bufo americanus, and Xenopus laevis were exposed to treatments for at least 96 h in a staticrenewal system using a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach to obtain confidence intervals. Consistent trends of greater toxicity with lower pH were observed, with the majority of models (five of seven models) showing significant (p < 0.05) inverse relations. Larval lethal concentration estimates were eight to twenty-three times less than those observed for embryos, indicating that the larval stages were more sensitive to treatments. Further, the median lethal concentration (LC50) values for the larvae were below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities for Release. Species sensitivity was similar, with an average larval 96-h LC50 of 0.89 mg acid equivalents (AE)/L at pH =.5 and 1.6 mg AE/L at pH 7, suggesting that X. laevis is a reasonable surrogate for native amphibians in laboratory toxicity testing. For the embryo tests, R. pipiens were slightly less sensitive in comparison with the other three species. Based on a hazard quotient analysis (EEC/LC50 > 1) for the most sensitive larval life stages, higher tier ecotoxicological testing under more realistic environmental conditions is strongly recommended.
Comparison of toxicity of zinc for soil microbial processes between laboratory-contamined and polluted field soils
Authors: Smolders Erik , Mcgrath Steve P. , Lombi Enzo , Karman Chris C. , Bernhard Roland , Cools Danielle , Van den Brande Karen , van Os Bertil , Walrave Nicolai
Published: November 2004

Soil microbial processes are readily disturbed by added zinc (Zn) in laboratory ecotoxicity tests. This study compares Zn toxicity between freshly spiked soils and soils that have been contaminated with Zn in the field. Soils were sampled in three transects (<80 m) toward galvanized electricity transmission towers (pylons). The soil total Zn concentrations gradually increased in each transect from background values (25-82 mg Zn/kg) to elevated Zn concentrations near the pylon (226-595 mg Zn/kg). Soil samples taken at the furthest distance from the Zn source were spiked with ZnCl2 to a range of total Zn concentrations similar to those in the transect. Nitrification, respiration, and N-mineralization rates were significantly reduced by added Zn in laboratoryspiked soils and were 9 to 95% (mean 32%) of the control values at largest doses depending on soil type and the microbial process. In contrast, these processes were either unaffected by soil Zn (p > 0.05) or increased significantly with soil Zn concentrations in the transect soils. These increases could not be explained by soil pH or%soil organic carbon. Leaching soils after spiking significantly lowered the toxic effects of Zn on nitrification or on substrate-induced respiration. The soil solution Zn concentrations of field soils were always smaller than in spiked soils at equivalent total Zn. Highest soil solution Zn concentrations were always lower than the soil-solution EC50s of spiked soils. It is concluded that there is a large discrepancy in microbial responses to elevated Zn between spiked soils (unleached) and field-contaminated soils and there is a need to explain this discrepancy in terms of Zn availability, adaptation processes, and additional soil factors controlling the microbial processes.
Productivity of American robins exposed to polychlorinated biphenyls, Housatonic River, Massachusetts, USA
Authors: Henning Miranda H. , Robinson Scott K. , Mckay Kelly J. , Sullivan Joseph P. , Bruckert Heather
Published: November 2004

American robins (Turdus migratorius) breeding in the Housatonic River (MA, USA) watershed were studied in the field in 2001 to determine whether productivity was adversely affected by exposure to polychlorinated biphenyls (PCBs), as would be suggested by extrapolation from laboratory studies on other avian species. The study involved identifying nests within the Housatonic River floodplain (target area) and in reference areas beyond foraging distance of the floodplain, monitoring clutch size and number hatched and fledged, collecting eggs and nestlings for analysis for PCBs, and testing for differences in productivity between populations. One hundred and six active robin nests were monitored. Although concentrations of PCBs in target specimens were more than two orders of magnitude greater than in reference specimens, the only statistically significant differences in productivity were inconsistent with an exposure-related effect. First-generation productivity of exposed robins was within the range of natural background variation. Bioequivalence tests confirmed that first-generation productivity was statistically and biologically equivalent in target and reference robins. These findings contrast with extrapolations from laboratory studies of other avian species.
Polychlorinated biphenyls and organochlorine pesticides in baltic and atlantic gray seal (Halichoerus grypus) pups
Authors: Sørmo Eugen G. , Skaare Janneche U. , JÜSsi Ivar , JÜSsi Mart , Jenssen BjØRn M.
Published: November 2004

Organochlorine pollutants (OCs), such as polychlorinated biphenyls (PCBs), DDT, chlordanes (CHLs), hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs) were determined in blubber biopsies from free-ranging Baltic and Atlantic gray seal (Halichoerus grypus) pups. Well-fed pups from the Baltic Sea had concentrations of DDT, PCBs, and HCHs that were 2 to 10 times higher than in corresponding pups from populations in the Atlantic Ocean. The OC pattern in the Baltic seals differed significantly from that of their Atlantic relatives, reflecting the predominance of regional point source inputs into the Baltic Sea and long-range atmospheric inputs into the Atlantic Ocean. The differences in the pattern of the compounds also indicated an enhanced metabolism of the more metabolizable compounds in the more contaminated Baltic seals. Surprisingly, the proportions of the high chlorinated and low-volatile PCB congeners (>6 Cl atoms) were comparable or lower in the Baltic pups as compared to the Atlantic pups. This difference might be due to Baltic seals occupying a lower trophic level than Atlantic seals and/or to the eutrophication situation in the Baltic Sea, which causes sedimentation of these PCB congeners. Significantly higherOCconcentrations were found in starved and/or abandoned Baltic pups as compared to well-fed pups. The most contaminated Baltic seal pups in the present study had PCB concentrations that are comparable or higher than those reported to impair the immune systems and vitamin A dynamics in phocids.
Hydroxylated and methylsulfone-containing metabolites of polychlorinated biphenyls in the plasma and blubber of bowhead whales (Balaena mysticetus)
Authors: Hoekstra Paul F. , Letcher Robert J. , O'Hara Todd M. , Backus Sean M. , Solomon Keith R. , Muir Derek C. G.
Published: November 2004

Bowhead whale (Balaena mysticetus) blubber (n = 20) and plasma (n = 19) samples were collected during the 1997 to 2000 Inuit subsistence harvests in Barrow, Alaska, USA, to quantify the concentrations of methylsulfone (MeSO2)-containing and hydroxylated (OH) polychlorinated biphenyl (PCB) metabolites in this cetacean. The distribution of MeSO2-PCBs in blubber was dominated by 4-MeSO2-substituted congeners, the most abundant being 4-MeSO2-CB-70, 3ǐ-MeSO2-CB-132, and 4-MeSO2CB-64. Mean (±1 standard error) sum (Σ) MeSO2-PCBs concentrations in blubber were low (6.23 ± 0.81 ng g−1 lipid normalized) compared to concentrations previously reported in other marine mammals. However, similar ratios of MeSO2-PCB metabolites to parent PCB congeners among marine mammals suggest that cytochrome P450 2B-like biotransformation and other necessary enzymemediated processes and mechanisms that influence the formation and clearance of MeSO2-PCBs exist in the bowhead whale. Pentachlorophenol was the most abundant halogenated phenolic compound quantified in bowhead plasma (1.55 ± 0.19 ng g−1 wet wt). Despite indirect evidence for arene epoxidation of the biphenyl moiety inferred from MeSO2-PCB formation, ΣOH-PCB concentrations in bowhead plasma were low (1.52 ± 0.31 ng g−1 wet wt) compared to humans and marine mammals and were comprised of only two detectable OH-PCB congeners (4ǐ-OH-CB-130 and 4-OH-CB-187). Further research is required to elucidate the toxicokinetics and distribution of OH-PCBs in this cetacean.
INDO
/
S
Authors: Voityuk Alexander A , Rösch Notker
Published: November 2004

The semiempirical method
INDO/S
is reviewed with regard to its role as a computational tool for calculating spectroscopic properties of molecular systems ranging from organic and biological molecules to nanoparticles. The theoretical background and the parameterization of the method as well as its accuracy and limitations are discussed. A brief overview of typical applications, comprising examples from organic, inorganic, and organometallic chemistry as well as biochemistry and material science, illustrates the performance of the
INDO/S
scheme in computational studies on excited‐state properties of molecules.
Survival of patients with periampullary carcinoma is predicted by lymph node 8a but not by lymph node 16b1 status
Authors: Connor S , Bosonnet L , Ghaneh P , Alexakis N , Hartley M , Campbell F , Sutton R , Neoptolemos J P
Published: November 2004

Background

The aim of this study was to assess the impact of metastatic disease in lymph nodes 8a and 16b1 (as defined by the Japanese Pancreas Society) on survival in patients with periampullary malignancy.

Methods

Patients undergoing resection for primary pancreatic ductal adenocarcinoma or intrapancreatic bile duct adenocarcinoma were identified from a prospective database (September 1997–May 2003).

Results

Thirteen of 54 and ten of 44 evaluable patients had metastatic involvement of lymph nodes 8a and 16b1 respectively. Metastatic involvement of lymph node 8a was associated with a significantly shorter median survival (197 versus 470 days; P = 0·003) but metastatic involvement of lymph node 16b1 did not affect survival (457 versus 503 days; P = 0·185). Multivariate analysis showed lymph node 8a status to be the strongest predictor of outcome (P = 0·006). Median survival of those with metastatic lymph node 8a was not significantly different from that of 81 patients with overt metastatic periampullary cancer at the time of diagnosis (98 days; P = 0·072)

Conclusion

Lymph node 8a was an independent prognostic factor in patients with periampullary malignancy, but lymph node 16b1 was not. Survival in those with metastatic lymph node 8a was not significantly different from that in patients with metastatic disease at presentation. Preoperative determination of lymph node 8a status may have important implications in selecting patients for treatment.