bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative stress and ozone: perception, signalling and response
Authors: BAIER MARGARETE , KANDLBINDER ANDREA , GOLLDACK DORTJE , DIETZ KARL‐JOSEF
Published: July 2005

The primary site of ozone interaction with plant cells is the extracellular matrix where ozone challenges the antioxidant protection of the cells. Accordingly, ozone sensitivity generally correlates with the ascorbate status of the apoplast, which is an important signal initiation point. In addition, ozone sensing takes place by covalent modification of redox‐sensitive components of the plasma membrane, for example ion channels like the plasma membrane Ca2+‐channels. Subsequent intracellular signal transduction is an intriguing network of hormone, Ca2+ and MAPK signalling pathways, significantly overlapping with oxidative burst‐induced pathogen signalling. Comparison of recent transcriptome analysis revealed that in addition to genes generally induced by all kinds of oxidative stress, for example, transcripts for PR‐proteins and most antioxidant enzymes, approximately one‐third of the responsive transcripts are ozone specific, indicating jasmonic acid, salicylic acid and ethylene‐independent redox signalling triggered by extracellular redox sensing.
Oxidant and antioxidant signalling in plants: a re‐evaluation of the concept of oxidative stress in a physiological context
Authors: FOYER CHRISTINE H. , NOCTOR GRAHAM
Published: July 2005

While the chemical nature of reactive oxygen species (ROS) dictates that they are potentially harmful to cells, recent genetic evidence suggests that in planta purely physicochemical damage may be much more limited than previously thought. The most potentially deleterious effect of ROS under most conditions is that at high concentrations they trigger genetically programmed cell suicide events. Moreover, because plants use ROS as second messengers in signal transduction cascades in processes as diverse as mitosis, tropisms and cell death, their accumulation is crucial to plant development as well as defence. Direct ROS signal transduction will ensue only if ROS escape destruction by antioxidants or are otherwise consumed in a ROS cascade. Thus, the major low molecular weight antioxidants determine the specificity of the signal. They are also themselves signal‐transducing molecules that can either signal independently or further transmit ROS signals. The moment has come to re‐evaluate the concept of oxidative stress. In contrast to this pejorative or negative term, implying a state to be avoided, we propose that the syndrome would be more usefully described as ‘oxidative signalling’, that is, an important and critical function associated with the mechanisms by which plant cells sense the environment and make appropriate adjustments to gene expression, metabolism and physiology.
Crop responses to ozone: uptake, modes of action, carbon assimilation and partitioning
Authors: FISCUS EDWIN L. , BOOKER FITZGERALD L. , BURKEY KENT O.
Published: July 2005

The inhibitory effects of tropospheric O3on crop photosynthesis, growth, and yield have been documented in numerous studies over the past 35 years. In large part, the results of this research supported governmental regulations designed to limit tropospheric O3levels to concentrations that affected crop production at economically acceptable levels. Recent studies have brought into question the efficacy of these concentration‐based O3standards compared with flux‐based approaches that incorporate O3uptake along with environmental and biotic factors that influence plant responses. In addition, recent studies provide insight into the biochemical mechanisms of O3injury to plants. Current interpretations suggest that upon entry into the leaf intercellular space O3rapidly reacts with components of the leaf apoplast to initiate a complex set of responses involving the formation of toxic metabolites and generation of plant defence responses that constitute variably effective countermeasures. Plant species and cultivars exhibit a range of sensitivity to O3, evident as heritable characteristics, that must reflect identifiable biochemical and molecular processes that affect sensitivity to O3injury, although their exact makeup remains unclear. Ozone clearly impairs photosynthetic processes, which might include the effects on electron transport and guard cell homeostasis as well as the better‐documented effects on carbon fixation via decreased Rubisco activity. Translocation of photosynthate could be inhibited by O3exposure as well. Further, the influence of tropospheric O3needs to be considered when assessing potential effects of rising concentrations of atmospheric CO2on crop production. Advances in O3flux modelling and improved understanding of biochemical and molecular effects of O3on photosynthetic gas exchange and plant defence processes are leading to more complete, integrated assessments of O3impacts on crop physiology that continue to support the rationale for maintaining or improving current O3air quality standards as well as providing a basis for development of more O3‐tolerant crop lines.
Introduction of picture archiving and communication system at The Townsville Hospital
Authors: Jackson PE , Langlois SLeP
Published: July 2005

The performance of a medical imaging department (MID) can be judged by the timing and availability of an image and its report to the treating physician, as this can impact on the patient's treatment, as well as the length and cost of a patient's hospitalization. The use of digital imaging has dramatically improved report turnaround time. In October 2001, The Townsville Hospital (TTH) was opened as a 460 bed greenfield site and as part of the installation a picture archiving and communication system, including web distribution of images and reports to wards and clinics, was included. This retrospective analysis of the MID at TTH is the first data on departmental productivity and individual workload and how these have changed since the hospital's opening 2 years ago, with some ideas for further improvement.
Complementary role of adjunctive breast magnetic resonance imaging and scintimammography in patients of all ages undergoing breast cancer surgery
Authors: Howarth D , Slater S , Lau P , Booker J , Clark D , Sillar R
Published: July 2005

The aims of this study were to assess breast MRI and scintimammography (SMM) for the detection of breast cancer, and to determine any complementary role of these tests to each other and conventional imaging. Seventy‐two patients (age 35–81 years) with a suspicious breast mass were investigated by mammography, breast ultrasound, breast MRI and SMM before undergoing surgical excision of the breast mass. Sensitivity, specificity and area under receiver operator characteristic curves were calculated for each test. Of the 72 patients, there were 66 proven malignant tumours, including two patients with bilateral breast cancer. When comparing the diagnostic sensitivity of breast MRI and SMM for lesion size, both tests showed higher sensitivities for lesions >25 mm in size, particularly for SMM. When these tests were compared for patient age, patients less than 51 years showed higher sensitivities for both tests. This was statistically significant for breast MRI. The overall respective diagnostic sensitivities for mammography, mammography with breast ultrasound, breast MRI and SMM were 56, 67, 86 and 85%. The differences were significant between mammography, mammography/ultrasound and both breast MRI and SMM. Breast MRI and SMM offer incremental diagnostic advantage in the diagnosis of breast cancer. Although improved diagnostic accuracy is seen in patients of all ages, those patients less than 51 years of age receive the greatest diagnostic benefit.
Adrenal metastases of malignant melanoma: Characteristic computed tomography appearances
Authors: Rajaratnam A , Waugh J
Published: July 2005

Malignant melanoma is an extremely aggressive form of cancer. Adrenal metastases are found in 50% of cases of malignant melanoma, and are most often clinically and biochemically silent. Clinical presentation varies, and the diagnosis of adrenal metastases is often made incidentally, and frequently years after treatment of the primary lesion. An adrenal mass lesion seen on a CT scan, greater than 5 cm in diameter, with central or irregular areas of necrosis/haemorrhage (and no lipomatous component) is characteristic of a metastasis from malignant melanoma, in the setting of normal gland function. If these features are bilateral, they are pathognomonic. Oval, low‐attenuation (on CT) adrenal masses less than 3 cm in diameter should not be considered benign in a patient with any prior history of melanoma. Careful imaging review of the adrenal glands should be undertaken in all patients with malignant melanoma. Early diagnosis of these distant metastases has important prognostic and therapeutic implications. The four cases presented illustrate the spectrum of presentations and clinical course of adrenal metastases from malignant melanoma. The accompanying CT images show the characteristic appearances of adrenal metastases.
Ultrasound detection of a subperiosteal abscess secondary to coalescent otomastoiditis
Authors: Grant RL , Piotto L
Published: July 2005

We report the unusual ultrasound appearance of coalescent otomastoiditis with subperiosteal abscess in a 3‐month‐old boy with a 1‐week history of an enlarging lump behind the left ear. Ultrasound examination of the lump revealed subcutaneous oedema with an abscess extending from a defect in the cranial vault as a result of extension of the inflammatory process. We believe that this sonographic appearance has not been previously described in the published literature.
Retroperitoneal plexiform neurofibroma mimicking psoas abscesses
Authors: Kalra N , Vijayanadh O , Lal A , Khandelwal N , Mukherjee KK , Suri S
Published: July 2005

Retroperitoneal plexiform neurofibroma is a rare finding in neurofibromatosis type I, or von Recklinghausen's disease. A case of retroperitoneal plexiform neurofibroma mimicking psoas abscesses is reported here with its CT and MRI findings.
Intratesticular varicocele
Authors: Browne RFJ , Geoghegan T , Ahmed I , Torreggiani WC
Published: July 2005

Extratesticular varicocele is a common clinical condition, occurring in up to 20% of the normal adult male population. It is characterized by dilatation of the veins of the spermatic cord and has well‐described sonographic appearances. Intratesticular varicocele is characterized by dilated intratesticular veins and is extremely rare. It usually, but not always, occurs in association with an ipsilateral extratesticular varicocele. We describe the sonographic and colour Doppler appearances of this poorly described entity in a middle‐aged man referred for evaluation of a painful left testicular swelling.
Peritoneo–scrotal communication: Demonstration by 99mtechnetium sulphur colloid scintigraphy
Authors: Bhattacharya A , Mittal BR
Published: July 2005

Continuous ambulatory peritoneal dialysis is a widely used and convenient alternative to haemodialysis in patients with renal failure. Occasionally, a scrotal swelling may develop during this procedure because of fluid passing through a patent processus vaginalis. We present a case report to illustrate the diagnostic use of radionuclide scintigraphy in this group of patients.
Contrast column interruption artefact in computed tomography pulmonary angiography
Authors: Tay KL , Ridley LJ
Published: July 2005

Interruption of the contrast column during inspiration can lead to non‐diagnostic CT pulmonary angiograms. The importance of this artefact will increase with more CT studies being performed for pulmonary embolism on multidetector row CT. We describe here an instance of such an artefact and discuss its aetiology.
Endovascular management of pseudoaneurysms of the splenic artery: experience with six patients
Authors: Venkatesh SK , Kumar S , Baijal SS , Phadke RV , Kathuria MK , Gujral RB
Published: July 2005

The purpose of this paper was to describe our experience with the endovascular management of splenic artery pseudoaneurysms (SAPA). Seven patients with documented SAPA on CT and/or angiography were considered for endovascular treatment. The pseudoaneurysms were located in the main splenic artery (n = 4) or its branches (n = 3). In one patient in whom the pseudoaneurysm was located in a hilar branch, selective catheterization of splenic artery failed. Metallic coils (n = 1), gelfoam and hydrogel particles (n = 1), metallic coils and gelfoam (n = 2), metallic coil, gelfoam and acrylic glue (n = 2) were used as embolization material in the remaining six patients. These patients were followed for a mean period of 11.3 months. Transcatheter embolization was successful in five patients with no procedure‐related complications. In one patient, embolization was incomplete and the patient underwent surgery, but died on the 10th postoperative day because of irreversible shock. Another patient, after successful embolization, underwent surgery for management of an associated pseudocyst. Endovascular treatment is a safe and effective method of management of SAPA.
Patient satisfaction with doctor–patient interaction in a radiotherapy centre during the severe acute respiratory syndrome outbreak
Authors: Tang JI , Shakespeare TP , Zhang XJ , Lu JJ , Liang S , Wynne CJ , Mukherjee RK , Back MF
Published: July 2005

An outpatient radiotherapy department assessed how precautions implemented during the severe acute respiratory syndrome (SARS) outbreak affected patient satisfaction with doctor–patient interaction and explored variables potentially influencing satisfaction. The information obtained would help prepare us for future infectious disease outbreaks. Outpatients seen during the outbreak completed a validated questionnaire assessing satisfaction with doctor–patient interaction. Additional items assessed included patients’ perception of SARS measures and patient demographics. Of 149 patients, 97% had heard of SARS, 92% believed SARS precautions necessary, and 54% believed contracting SARS was possible despite the precautions. Patients were satisfied with doctors wearing masks (97%), temperature checks (97%), and patients wearing masks (96%). Despite the high satisfaction levels with SARS precautions, 24% believed it had adversely affected doctor–patient interaction. With regards to doctor–patient interaction, 94% of patients were satisfied. Patients were most satisfied with the ‘information exchange’ domain (mean score 3.23 out of 4) compared to other domains (P < 0.0001, 100.00% confidence) and were less satisfied with the ‘empathy’ domain compared to other domains (P < 0.0001, 100.00% confidence). Patients were most satisfied with understanding their treatment plan (100%), doctor being honest (97%) and being understood (96%). Patients were least satisfied with information about caring for their illness (61%), that the visit could be better (59%), and the doctor showing more interest (58%). On multivariate analysis, patients who were less satisfied with SARS measures were significantly less satisfied with doctor–patient interaction (P = 0.0001). Dissatisfaction with SARS measures was associated with significant dissatisfaction for questions in all domains. Older age and non‐breast cancer patients were also less satisfied with doctor–patient interaction. Most (94%) of patients were satisfied with doctor–patient interaction, despite implementation of infectious disease prevention measures. However, patients who were dissatisfied with the SARS precautions had poorer satisfaction. In particular, physician empathy appeared to be most adversely affected. The results have relevance to any radiotherapy department preparing contingency plans in the event of infectious disease outbreaks.
Importance of radiation time and dose factors on outcome for childhood medulloblastoma*
Authors: Back M , Ahern V , Berry M , Borg M , Sexton M , Cameron F , Stevens G , Allison R , Childs J , Barton M
Published: July 2005

The purpose of this study was to investigate the relationship of posterior fossa radiation therapy duration (PFRTD) and relapse‐free survival (RFS) following adjuvant craniospinal RT for childhood medulloblastoma. A retrospective audit was performed assessing all children aged <18 years managed with adjuvant craniospinal RT for medulloblastoma in Australia and New Zealand in 1980–1993. Children receiving prolonged (>180 days) pre‐RT chemotherapy were excluded. Data were obtained for potential prognostic factors in domains of patient, tumour and treatment factors. Radiation therapy time factors assessed were PFRTD and time interval from surgery to commencement of RT (SRTD). The end‐point assessed was RFS and analysis was performed using Cox regression and Kaplan–Meier survival. One hundred and eighty‐nine children were identified from 10 oncology units, with data available from 182 children for analysis. Median follow up was 5.3 years. Seventy‐three per cent of children presented with disease confined to the cerebellum; 13% had initial neuraxis disease. Macroscopic resection was described in 54%; 42% received adjuvant chemotherapy. Median RT dose and RT duration to PF was 55 Gy and 45 days, respectively. Seventy‐eight relapses occurred with a 10‐year actuarial RFS of 58.2% (standard error ± 4%). On univariate analysis, increasing PF dose (P = 0.002), age >5 years (P = 0.006), and more thorough extent of surgical resection (P = 0.043) were associated with improved RFS; PFRTD (P = 0.20) and SRTD (P = 0.51) were not associated with RFS. On multivariate analysis, although both PF dose (P = 0.004) and extent of surgery (P = 0.045) remained strongly significant, RT duration was now associated with RFS (P = 0.049). Other factors assessed that did not reach significance were patient age, local tumour extent, presence of internal shunt and use of chemotherapy. The importance of local treatment factors was confirmed in this audit with established prognostic factors such as primary tumour macroscopic resection and adequate PF RT dose being associated with RFS. A treatment time effect is weakly suggested, although less significant than RT dose delivered.
Carbohydrates in xenotransplantation
Authors: Ezzelarab Mohamed , Ayares David , Cooper David KC
Published: July 2005

The success of allotransplantation has led to an increasing shortage of human organs from deceased donors. This crisis could be resolved by the use of organs from an anatomically suitable animal, such as the pig. The pig and human have, however, been evolving differently for approximately 80 million years, and numerous immunological and physiological barriers have developed that need to be overcome. Differences in carbohydrate epitopes on pig and human cells have been found to play a major role in some of the immunological barriers that have been identified to date. The rejection caused by the presence of galactose‐α1,3‐galactose (Gal) on the pig vascular endothelium and of natural anti‐Gal antibodies in humans has recently been prevented by the breeding of pigs that do not express Gal, achieved by knocking out the gene for the enzyme α1,3‐galactosyltransferase, which was made possible by the introduction of nuclear transfer/embryo transfer techniques.N‐glycolylneuraminic acid (the so‐called Hanganutziu‐Deicher antigen) has been identified as another carbohydrate antigen present in pigs that may need to be deleted if xenotransplantation is to be successful, although some doubt remains regarding its importance. There remain other antipig antibodies against hitherto unidentified antigenic targets that may well be involved in graft destruction; their possible carbohydrate target epitopes are discussed.
Expression of chemokines on the surface of different human endothelia
Authors: Hillyer Philippa , Male David
Published: July 2005

Expression of chemokines at the endothelial surface depends on their rate of synthesis, the capacity of the endothelium to bind chemokines and the rate of clearance from the surface. The aim of this study was to establish how these factors depend on the chemokine and the tissue of origin of the endothelium. Human lung and dermal microvascular endothelium, saphenous and umbilical vein endothelium, and a bone marrow endothelial line were assayed in vitro. Chemokine expression, localization and transport was measured by immunoassay and confocal microscopy. All endothelia bound CCL3 (MIP‐1α), CCL5 (RANTES) and CXCL10 (IP‐10). CCL3 and CCL5 bound at high levels, and CXCL10 bound less strongly. However, the profile of chemokine expression varied between endothelia, and different chemokines were shown to bind to the endothelial surface by distinct mechanisms. The half‐life of CCL3 and CCL5 at the cell surface was approximately 30 min and chemokines were cleared primarily by endocytosis into caveolae. Endothelia from different tissues synthesize distinctive sets of chemokines, but the profile of surface‐expressed chemokines also depends on the distinctive characteristics of each endothelia. These two mechanisms may contribute to the differential recruitment of leucocyte subsets to different tissues.
Liver inflammation and cytokine production, but not acute phase protein synthesis, accompany the adult liver progenitor (oval) cell response to chronic liver injury
Authors: Knight Belinda , Matthews Vance B , Akhurst Barbara , Croager Emma J , Klinken Elizabeth , Abraham Lawrence J , Olynyk John K , Yeoh George
Published: July 2005

Oval cells are facultative liver progenitor cells, which are invoked during chronic liver injury in order to replenish damaged hepatocytes and bile duct cells. Previous studies have observed inflammation and cytokine production in the liver during chronic injury. Further, it has been proposed that inflammatory growth factors may mediate the proliferation of oval cells during disease progression. We have undertaken a detailed examination of inflammation and cytokine production during a time course of liver injury and repair, invoked by feeding mice a choline‐deficient, ethionine‐supplemented (CDE) diet. We show that immediately following initial liver injury, B220‐expressing leucocytes transiently infiltrate the liver. This inflammatory response occurred immediately before oval cell numbers began to expand in the liver, suggesting that the two events may be linked. Two waves of liver cytokine production were observed during the CDE time course. The first occurred shortly following commencement of the diet, suggesting that it may represent a hepatic acute phase response. However, examination of acute phase marker expression in CDE‐fed mice did not support this hypothesis. The second wave of cytokine expression correlated with the expansion of oval cell numbers in the liver, suggesting that these factors may mediate oval cell proliferation. No inflammatory signalling was detected following withdrawal of the injury stimulus. In summary, our results document a close correlation between inflammation, cytokine production and the expansion of oval cells in the liver during experimental chronic injury.
Immune response to Thomsen–Friedenreich disaccharide and glycan engineering
Authors: Irazoqui Fernando J , Sendra Victor G , Lardone Ricardo D , Nores Gustavo A
Published: July 2005

Cancer‐associated mucins show frequent alterations of their oligosaccharide chain profile, with a switch to unmask normally cryptic O‐glycan backbone and core regions. Epithelial tumour cells typically show overexpression of the uncovered Galβ1‐3GalNAcα‐O‐Ser/Thr (Core 1) structure, known as the T antigen or the Thomsen–Friedenreich antigen, the oligosaccharide chain of which is called the Thomsen–Friedenreich disaccharide (TFD). T antigen expression has been associated with immunosuppression, metastasis dissemination, and the proliferation of cancer cells. Several different strategies have been used to trigger a specific immune response to TFD. Natural T antigen and synthetic TFD residues have low immunodominance. In the T antigen, flexibility of the glycosidic bond reduces the immunogenicity of the sugar residue. Enhanced rigidity should favour certain glycan conformations and thereby improve TFD immunotargeting. We propose the term ‘glycan engineering’ for this approach. Such engineering of TFD should reduce the flexibility of its glycan moiety and thereby enhance its stability, rigidity and immunogenicity.
CYTOTOXINS AND IMMUNOTOXINS FOR CANCER THERAPY: CLINICAL APPLICATIONS
Authors: Pietersz Geoffrey
Published: July 2005

Immunology and Cell Biology (2005) 83, 450; doi:10.1111/j.1440‐1711.2005.01360.x
Blood brothers: Carbohydrates in xenotransplantation and cancer immunotherapy
Authors: Ramsland Paul A
Published: July 2005

Carbohydrate antigens have a central role in the hyperacute rejection of animal‐to‐human organ grafts (xenotransplantation) and they are emerging in importance in the immunotherapy of cancer. This article traces the historical origins of the discovery of key carbohydrate antigens and explores the future impact of recent technological advances of the field of glycobiology as it relates to xenotransplantation and cancer.
Event‐related potentials as an index of similarity between words and pictures
Authors: Watson Todd D. , Azizian Allen , Berry Stephen , Squires Nancy K.
Published: July 2005

This report examines the ERP correlates of processing nontarget stimuli that are conceptually, but not perceptually, similar to a target. In two studies, the P300 component was examined in healthy adults during a multistimulus oddball paradigm. The stimuli were pictures of five objects and their five corresponding names. Participants were required to keep a mental count of number of target presentations. In Experiment 1, the target was the word “globe.” Both the word target and the nontarget picture of the globe elicited large P300s, though the P300 to the picture was smaller in amplitude. No other stimulus elicited a prominent P300. In Experiment 2, the target was the picture of the globe, and the word was considered to be the related nontarget. Again, the target elicited a large P300. However, in this case the related nontarget stimulus failed to elicit a P300. The relevance of the data to theories of word/picture processing is discussed.
Effects of perceptual processing demands on startle eyeblink modification
Authors: Rissling Anthony J. , Dawson Michael E. , Schell Anne M. , Nuechterlein Keith H.
Published: July 2005

Startle eyeblink modification was measured during a continuous performance test (CPT) with either clearly focused stimuli or visually degraded stimuli to measure the effects of early perceptual processing demands on startle modification. A startling noise was presented either 120, 240, or 1200 ms following target and nontarget CPT stimuli. In the degraded stimulus CPT, startle inhibition at 240 ms was greater following targets than nontargets and was as great during targets at 240 ms as at 120 ms, whereas in the clearly focused CPT, inhibition declined significantly from 120 to 240 ms. The results indicate that maximum prepulse inhibition is extended in time when the task involves discrimination of degraded visual stimuli and when early perceptual processing demands are high. At 1200 ms, targets and nontargets produced nondifferential inhibition during both CPTs, suggesting that modality‐specific attention occurred equally for the two tasks.
Positive difference in ERPs reflects independent processing of visual changes
Authors: Kimura Motohiro , Katayama Jun'ichi , Murohashi Harumitsu
Published: July 2005

To elucidate the nature of the processing of visual stimulus changes, ERPs were recorded while 12 participants performed an S1–S2 matching task with multifeature stimuli. Each trial consisted of two sequentially presented stimuli (S1–S2), where S2 was either the same as S1, different from S1 only in color, different only in shape, or different in both color and shape. The four trial types were presented in random order with equal probability, and participants responded to one of these types in separate blocks. Relative to the no‐change stimuli, the change stimuli elicited posterior positivity with different topography according to changing features ranging from 100 to 180 ms in all tasks. The amplitude and topography of the positivity in response to the both changes were the respective sums of those to changes in the corresponding single features. These results suggest that a feature‐specific change detection system exists in the human visual system.
Age differences in attentional control: An event‐related potential approach
Authors: Kray Jutta , Eppinger Ben , Mecklinger Axel
Published: July 2005

We examined age differences in event‐related potentials (ERPs) associated with attentional control of task‐set selection and response interference by means of a cue‐based switching paradigm in which participants performed the color or word Stroop task. The results of ERPs in the cue interval indicated that P3 latencies were slowed for older adults, suggesting age‐related slowing in updating currently relevant task sets. Older adults also showed a larger CNV under switching than nonswitching conditions, indicating age differences in maintaining task sets over longer periods of time. The results of target‐locked ERPs revealed a negativity to incompatible Stroop trials (Ni) that was prolonged for older adults, suggesting age differences in early conflict processing. Response‐locked ERPs showed a negative deflection to incompatible Stroop trials (CRN) only for younger adults, suggesting age differences also in response‐related conflict processing.
Distinct M50 and M100 auditory gating deficits in schizophrenia
Authors: Hanlon Faith M. , Miller Gregory A. , Thoma Robert J. , Irwin Jessica , Jones Aaron , Moses Sandra N. , Huang Mingxiong , Weisend Michael P. , Paulson Kim M. , Edgar J. Christopher , Adler Lawrence E. , Cañive Jose M.
Published: July 2005

The time course of the schizophrenia auditory gating deficit may provide clues to mechanisms of impaired cognition. Magnetoencephalography was recorded during a standard paired‐click paradigm. Using source strength of the M50 and M100 components for each click, calculated from dipole locations identified as underlying each component for the first click, a ratio of the second divided by the first was used to measure gating. Patients showed a left‐hemisphere gating deficit in M50 and a bilateral gating deficit in M100. Hypothesizing that an early deficit may affect later processing, hierarchical regression was used to examine variance shared between the components. A left‐hemisphere M100 gating deficit was coupled with the left M50 gating deficit. In contrast, a right‐hemisphere M100 gating deficit was unrelated to M50 gating in either hemisphere. Investigations of interhemisphere gating relations may clarify group differences in regional connectivity and their role in gating.
Parametric exploration of the fear‐inhibited light reflex
Authors: Hourdaki Eugenia , Giakoumaki Stella G. , Grinakis Vangelis , Theou Katerina , Karataraki Maria , Bitsios Panos
Published: July 2005

The effect of various parameters on the mediation of the fear‐inhibited light reflex was examined. The light reflexes of 16 healthy men were measured across four light probe intensities, either in the presence of white noise alone or when the white noise was associated with the threat of either an electric shock or an acoustic sound blast. The white noise alone did not affect the light reflex amplitude. Both types of threat were subjectively anxiogenic and inhibited the light reflex across all light probe intensities, the threat of shock being more potent than the threat of sound blast. Importantly, the effect of either type of threat on the light reflex amplitude was found to increase with increasing light probe intensity, suggesting that brighter light probes may become more relevant motivationally in the threat condition, thus attracting greater allocation of attentional/cognitive resources.
Context modulation of memory for fear extinction in humans
Authors: Milad Mohammed R. , Orr Scott P. , Pitman Roger K. , Rauch Scott L.
Published: July 2005

Distinct memories are formed during fear conditioning and subsequent extinction. In animals, the expression of the latter is gated by the context. The recall of extinction memory after a long delay, and the contextual modulation thereof, has not been directly tested in humans. Mentally healthy volunteers underwent a 2‐day fear conditioning and extinction protocol that examined the recall of extinction memory and its relationship to context. Conditioned stimuli were paired with an aversive electric shock in one visual context and extinguished in a different context. Extinction recall and renewal were examined 24 h after training. We found that skin conductance responses were small when the conditioned stimulus was presented in the extinction context, but responses were renewed when the conditioned stimulus was presented in the conditioning context. This finding demonstrates context dependency of extinction recall in humans.
ERPs of metaphoric, literal, and incongruous semantic processing in schizophrenia
Authors: Iakimova Galina , Passerieux Christine , Laurent Jean‐Paul , Hardy‐Bayle Marie‐Christine
Published: July 2005

The ability of schizophrenia patients to access metaphorical meaning was studied on the basis of psycholinguistic models of metaphor processing. ERPs were recorded from 20 schizophrenic and 20 control participants who were asked to read metaphorical, literal, and incongruous sentences and to judge their meaningfulness. In all participants, incongruous endings to sentences evoked the most negative N400 amplitude, whereas literal endings evoked more negative N400 amplitude than metaphorical ones, consistent with the direct model of metaphor processing. Although the patients had ERPs patterns that were similar to controls, they exhibited a more negative N400 amplitude for all sentences, LPC amplitude reduction, and latency delay in both components. The results suggest that schizophrenics have no specific anomalies in accessing the meaning of metaphors but are less efficient in integrating the semantic context of all sentences—both figurative and literal.
Prepulse inhibition of the acoustic startle reflex and oculomotor control
Authors: Ettinger Ulrich , Hejda Sylvia , Flak Vanja , Corr Philip J.
Published: July 2005

Prepulse inhibition and the suppression of reflexive saccades on the antisaccade task are thought to tap inhibitory function. Reports of a lack of association between these measures suggest that they reflect different facets of inhibition. This study aimed to reexamine this relationship in a large sample and investigate the association of prepulse inhibition with oculomotor tasks that require inhibition of a reflexive saccade with lower concurrent processing demands than antisaccades, namely the oculomotor delayed response and fixation with distractors tasks. One hundred and seven healthy volunteers took part. Prepulse inhibition was uncorrelated with oculomotor performance. The error rate was highest for antisaccades, intermediate for the delayed response task, and lowest for fixation with distractors, and was correlated across tasks. These findings provide no evidence of a relationship between prepulse inhibition and oculomotor inhibition. Failure in suppressing reflexive saccades toward a peripheral target may represent a common inhibitory component underlying these oculomotor tasks.
Use of an Immediate Provisional Implant   to Support a Full‐Arch Interim Restoration: A Clinical Report
Authors: Lee Jae‐Hoon , Frias Val , Lee Keun‐woo
Published: July 2005

The use of provisional implants as the sole or adjunct mean of stabilization for interim fixed partial dentures has gained popularity in implant prosthodontic treatment. These implants can be used between submerged implants during the healing phase to provide support for interim fixed or removable partial dentures. In this clinical report, a provisional implant used to provide support for a full‐arch fixed interim restoration is described. Positioned between adjacent conventional implants, the provisional implant was placed during the same surgical procedure. As a result, an immediate acrylic fixed partial denture supported by natural teeth and the provisional implant provided a comfortable and esthetic interim restoration during the osseointegration period.
The Wetting of Surface‐Treated Silicone Impression Materials by Gypsum Mixes Containing Disinfectants and Modifiers
Authors: Abdelaziz Khalid M. , Combe Edward C. , Hodges James S.
Published: July 2005

Purpose:
This work evaluated wettability of silicone impression surfaces by gypsum mixes containing disinfectants.

Materials and Methods:
Two types of dental stone were modified by mixing with aqueous solutions of either sodium hypochlorite or povidone iodine. These materials were subjected to further modification by adding a mixture of 1% gum arabic and 0.132% calcium hydroxide to reduce the water requirement of the hemihydrate. Mix consistency tests were carried out to determine the effect of the disinfectants and the modifying additives on the mix fluidity. Contact angles of the mixed materials were measured when they were poured against a polyvinylsiloxane impression material that had undergone the following treatments (1) no treatment (control), (2) surfactant treated, (3) disinfectant treated, and (4) treated with both surfactant and disinfectant. One‐way analysis of variance (ANOVA) was carried out using Dunnett's method to determine if experimental groups were significantly different from the control.

Results:
Gypsum mix consistency was reduced by the presence of combined gum arabic and calcium hydroxide additives. Contact angle data showed that the additives and disinfectants incorporated into the gypsum had, in general, no beneficial effect on the wetting of an untreated silicone surface, or a surface treated with surfactant. In some instances, better wetting was obtained with disinfectant‐treated surfaces, and surfaces that had been disinfected and treated with surfactant.

Conclusions:
Fluidity of the mixed gypsum was affected by the modifying additives. Chemical disinfectants incorporated in gypsum have little effect on the wetting behavior of dental gypsum. Modifying dental stone powders with gum arabic and calcium hydroxide additives (before mixing at the manufacturers' recommended liquid/powder ratios), improved the wetting behavior of the mixed materials in some cases, but results were not consistent.
The Effect of a New Denture Adhesive on Bite Force Until Denture Dislodgement
Authors: Özcan Mutlu , Kulak Yasemin , De Baat Cees , Arikan Ayla , Ucankale Mert
Published: July 2005

Purpose:
Denture adhesives are used to improve the denture retention and comfort of complete denture wearers. The purpose of this investigation was to establish the effect of a new denture adhesive on maximum bite force until denture dislodgement (BFDD) after adhesive application.

Materials and Methods: Fifteen denture‐wearing patients (7 female, 8 male, mean age: 64 years) were involved in the study. The BFDD measurements were performed using a disposable gnathometer with a 1 to 10 scale. During one of the treatment sessions, the maximum BFDD with the pre‐existing maxillary dentures using denture adhesive were measured. The measurements were also made at the baseline without adhesive and after the 1st, 2nd, 4th, and 6th hours following the application of the denture adhesive. The same procedure was applied to the new dentures about 2 weeks after the delivery of the dentures. The data were collected and statistically analyzed using ANOVA and Student's t‐test.

Results: Consistent improvement was observed in BFDD when adhesive was used for all time intervals from the baseline (mean: 1.54 units, 3.20 units) to 6 hours (mean: 3.99 units, 4.60 units) for both pre‐existing dentures (p= 0.003) and new dentures (p= 0.05), respectively.

Conclusions: The results of this in vivo study suggest that the denture adhesive tested could effectively increase BFDD for up to 6 hours after application.
Trypanosome Alternative Oxidase is Regulated Post‐transcriptionally at the Level of RNA Stability
Authors: CHAUDHURI MINU , SHARAN RITA , HILL GEORGE C.
Published: July 2005

ABSTRACTIn the bloodstream form of African trypanosomes, trypanosome alternative oxidase (TAO), the non‐cytochrome ubiquinol:oxidoreductase, is the only terminal oxidase of the mitochondrial electron transport system. TAO is developmentally regulated during mitochondrial biogenesis in this parasite. During in vitro differentiation ofTrypanosoma bmceifrom the bloodstream to the procyclic form, the overall rate of oxygen consumption decreased about 80%. The mode of respiration changed over a 2‐ to 3‐wk period from a cyanide‐insensitive, SHAM‐sensitive pathway to a predominantly cyanide‐sensitive pathway. The TAO protein level gradually decreased to the level present in the procyclic forms during this 3‐wk period. However, within the first week of differentiation, the TAO transcript level decreased about 90% and then in the following weeks it reached the level present in the established procyclic form, that is about 20% of that in bloodstream forms. Like other trypanosomatid genes TAO transcript synthesis remains unaltered in fully differentiated bloodstream and procyclic trypanosomes. The half‐life of the TAO mRNA was about 3.2 h in the procyclic trypanosomes, whereas the TAO transcript level remained unaltered even after 4 h of incubation with actinomycin D in bloodstream forms. Inhibition of protein synthesis resulted in about a four‐fold accumulation of the TAO transcript in the procyclic trypanosomes, comparable to the level present in the bloodstream forms. Thus, TAO is regulated at the level of mRNA stability and de novo protein synthesis is required for the reduction of the TAO mRNA pool in the procyclic form.
Infectivity and Virulence of Leishmania donovani Promastigotes+a Role for Media, Source, and Strain of Parasite
Authors: DEY TUHINA , AFRIN FARHAT , ANAM KHAIRUL , ALI NAHID
Published: July 2005

ABSTRACT. Transformation of promastigotes of Leishmania donovani strain AG83 from amastigotes derived from an infected animal was studied in three media, Schneider's Drosophila medium (SDM), Medium 199 (M199), and biphasic M199 (B‐M199) with 10% fetal bovine serum. The media, SDM and B‐M199, both supported a more efficient transformation of promastigotes in comparison with M199. Infectivity studies in hamsters and BALB/c mice showed that promastigotes isolated in B‐M199 were several folds more infective than those obtained from M199. Comparison of the infectivity and virulence of promastigotes of AG83, with a recent isolate of kalaazar, SL94, harvested under similar conditions, revealed greater infectivity of SL94 for both macrophages and animal models. The present study demonstrates that the medium used for the conversion of amastigotes to promastigotes plays a major role in determining the infectivity of the freshly transformed L. donovani promastigotes in hamsters and BALB/c mice. The source and the strain of the parasite also influence the outcome of L. donovani infection.
Electrokaryotypes of Macronuclei of Several Paramecium Species
Authors: RAUTIAN MARIA S. , POTEKHIN ALEXEY A.
Published: July 2005

ABSTRACT
A comparative study of macronuclear DNA molecules from the following Paramecium species+the P. aurelia complex, P. caudatum, P. bursaria, P. putrinum and P. multimicronucleatum was performed using pulsed‐fleld gel electrophoresis. The electrophoretic pattern was constant and unique for each species, and is referred to herein as its electrokaryotype. Large differences were observed between Paramecium species according to the range and major size of macronuclear DNA fragments, while different strains of the same species, even belonging to different syngens, were characterized by the same electrokaryotype. In this respect sibling species from the P. aurelia complex are as similar as syngens in other Paramecium species, but are unlike conventional species. The principles and value of electrokaryotype analysis for application to ciliates are discussed.
Two Forms of Membrane‐Bound Sphingosine Kinase in Tetrahymena and Activity Changes During Growth and the Cell Cycle
Authors: WANG SHULIN , BANNO YOSHIKO , NOZAWA YOSHINORI
Published: July 2005

ABSTRACT
Sphingosine kinase is responsible for the formation of sphingosine‐1‐phosphate, a sphingolipid mediator with important roles in numerous physiological processes. The sphingosine kinase activity of Tetrahymena pyriformis was recovered predominantly in the particulate fraction and it could be solubilised in 1%β‐octylglucoside. Anion‐exchange chromatography resolved the β‐ocrylglu‐ coside‐solubilised sphingosine kinase activity into two peaks corresponding to proteins of Mr 140,000 and 80,000 respectively, as determined by subsequent size exclusion chromatography on Superdex 200.N,N‐dimethylsphingosine did not inhibit the sphingosine kinase activity in either fraction, whereas D,l‐threo‐dihydrosphingosine inhibited sphingosine phosphorylation by the Mr 80,000 kinase but had no effect on the Mr 140,000 kinase activity. The activities also showed different stimulatory responses to Triton X‐100 or NaCl. Overall, the results suggest the existence in Tetrahymena of two distinct membrane‐associated sphingosine kinases. The kinase activity determined at the different culture stages showed a transient elevation at the mid‐logarithmic phase. Further, the sphingosine kinase activity was examined during the synchronous cell division induced by cyclic heat treatments in T. pyriformis. We report for the first time that the sphingosine kinase activity greatly increased at 30 to 45 min after the end of heat treatment prior to the synchronous cell division (75 min), suggesting that the activity changes were associated with the cell cycle and that the up‐regulated sphingosine kinase activity would be required for the initiation of the oncoming synchronous cell division in Tetrahymena cells.
Tolerance of Soil Flagellates to Increased NaCl levels
Authors: EKELUND FLEMMING
Published: July 2005

ABSTRACT. The ability of heterotrophic flagellates to survive and adapt to increasing salinities was investigated in this study. Whole soil samples were subjected to salinities corresponding to marine conditions and clonal cultures were used to perform growth and adaptation experiments at a wide range of different salinities (0–50 ppm). More morphotypes tolerant to elevated NaCl levels were found in road verge soil that was heavily exposed to de‐icing salt than in less exposed soils, though there were fewer tolerant than intolerant morphotypes in all soils examined. Heterotrophic flagellates isolated on a freshwater medium from a non‐exposed soil were unable to thrive at salinities above 15 ppt, and showed reduced growth rates even at low salt salinities (1–5 ppt). The findings suggest that heterotrophic soil flagellates are less tolerant to NaCl than their aquatic relatives, possibly due to their long evolutionary history in soil, and support the idea that identical morphospecies may differ considerably with respect to physiology
Isolation of Purified Oocyst Walls and Sporocysts from Toxoplasma gondii
Authors: EVERSON WILLIAM V. , WARE MICHAEL W. , DUBEY J. P. , LINDQUIST H. D. ALAN
Published: July 2005

ABSTRACT
Toxoplasma gondii oocysts are environmentally resistant and can infect virtually all warm‐blooded hosts, including humans and livestock. Little is known about the biochemical basis for this resistance of oocysts, and mechanism for excystation of T. gondii sporozoites. The objective of the present study was to evaluate different methods (mechanical fragmentation, gradients, flow cytometry) to separate and purify T. gondii oocyst walls and sporocysts. Oocyst walls were successfully separated and purified using iodixanol gradients. Sporocysts were successfully separated and purified using iodixanol and Percoll gradients. Purification was also achieved by flow cytometry. How cytometry with fluorescence‐activated cell sorting (FACS) yielded analytical quantities of oocyst walls and intact sporocysts. Flow cytometry with FACS also proved useful for quantitation of purity obtained following iodixanol gradient fractionation. Methods reported in this paper will be useful for analytical purposes, such as proteomic analysis of components unique to this life cycle stage, development of detection methods, or excystation studies.