bluuebunny/crossref_metadata_2025 huggingface dataset:
Response shift masks the treatment impact on patient reported outcomes (PROs): the example of individual quality of life in edentulous patients
Authors: Ring Lena , Höfer Stefan , Heuston Frank , Harris David , O'Boyle Ciaran A
Published: September 2005

Background

Quality of life (QoL) is now established as an important outcome for evaluating the impact of disease, and for assessing the efficacy of treatments. However, individuals change with time and the basis on which they make a QoL judgement may also change, a phenomenon increasingly referred to as response shift. Here, the individual may change his or her internal standards, values, and/or conceptualization on the target construct as a result of external factors such as a treatment or a change in health status. This has important implications for assessing the effects of treatments as a change in QoL may reflect a response shift, a treatment effect, or a complex combination of both. In this study, we used an individualised quality of life (IQoL) measure, the SEIQoL, together with a then-test to determine whether response shift would influence the measurement of treatment efficacy in edentulous patients.

Methods

Data are reported here for the first phase of a randomised controlled clinical trial designed to assess the impact, on IQoL, of implant supported dentures compared with high quality conventional dentures. IQoL was measured using the SEIQoL-DW in 117 patients (mean age 64.8; 32% male) at baseline (T1) and 3 months (T2) after receiving high quality conventional dentures. The work was carried out in dental teaching hospitals in Dublin and Belfast.

Results

Unadjusted SEIQoL index scores revealed no significant impact of treatment at three months (baseline: 75.0; 3 months: 73.2, p = .33, n.s.). However, the then-test at 3 months revealed that patients retrospectively rated their baseline IQoL as significantly lower (P < .001) than they had rated it at the time (then-test baseline: 69.2). Comparison of the 3 month scores with this readjusted baseline indicated a significant treatment effect (then-test baseline: 69.2; 3 months: 73.2, p = 0.016). 81% of patients nominated at least one different IQoL domain at 3 months.

Conclusion

The positive impact of denture treatment for edentulous patients on IQoL was seen only when response shifts were taken into consideration. The nature of the response shifts was highly complex but the data indicated a degree of re-conceptualisation and reprioritisation. Assessment of the impact of treatments using patient-generated reports must take account of the adaptive nature of patients.
Boundary effects influence velocity of transverse propagation of simulated cardiac action potentials
Authors: Sperelakis Nicholas , Kalloor Bijoy , Ramasamy Lakshminarayanan
Published: September 2005

Background

We previously demonstrated that transverse propagation of excitation (cardiac action potentials simulated with PSpice) could occur in the absence of low-resistance connections (gap – junction channels) between parallel chains of myocardial cells. The transverse transmission of excitation between the chains was strongly dependent on the longitudinal resistance of the interstitial fluid space between the chains: the higher this resistance, the closer the packing of the parallel chains within the bundle. The earlier experiments were carried out with 2-dimensional sheets of cells: 2 × 3, 3 × 4, and 5 × 5 models (where the first number is the number of parallel chains and the second is the number of cells in each chain). The purpose of the present study was to enlarge the model size to 7 × 7, thus enabling the transverse velocities to be compared in models of different sizes (where all circuit parameters are identical in all models). This procedure should enable the significance of the role of edge (boundary) effects in transverse propagation to be determined.

Results

It was found that transverse velocity increased with increase in model size. This held true whether stimulation was applied to the entire first chain of cells or only to the first cell of the first chain. It also held true for retrograde propagation (stimulation of the last chain). The transverse resistance at the two ends of the bundle had almost no effect on transverse velocity until it was increased to very high values (e.g., 100 or 1,000 megohms).

Conclusion

Because the larger the model size, the smaller the relative edge area, we conclude that the edge effects slow the transverse velocity.
A comparative study of a theoretical neural net model with MEG data from epileptic patients and normal individuals
Authors: Kotini A , Anninos P , Anastasiadis AN , Tamiolakis D
Published: September 2005

Objective

The aim of this study was to compare a theoretical neural net model with MEG data from epileptic patients and normal individuals.

Methods

Our experimental study population included 10 epilepsy sufferers and 10 healthy subjects. The recordings were obtained with a one-channel biomagnetometer SQUID in a magnetically shielded room.

Results

Using the method of x2-fitting it was found that the MEG amplitudes in epileptic patients and normal subjects had Poisson and Gauss distributions respectively. The Poisson connectivity derived from the theoretical neural model represents the state of epilepsy, whereas the Gauss connectivity represents normal behavior. The MEG data obtained from epileptic areas had higher amplitudes than the MEG from normal regions and were comparable with the theoretical magnetic fields from Poisson and Gauss distributions. Furthermore, the magnetic field derived from the theoretical model had amplitudes in the same order as the recorded MEG from the 20 participants.

Conclusion

The approximation of the theoretical neural net model with real MEG data provides information about the structure of the brain function in epileptic and normal states encouraging further studies to be conducted.
Gene Expression Profile Predicts Patient Survival of Gastric Cancer After Surgical Resection
Authors: Chen Chiung-Nien , Lin Jen-Jen , Chen Jeremy J. W. , Lee Po-Huang , Yang Ching-Yao , Kuo Min-Liang , Chang King-Jen , Hsieh Fon-Jou
Published: September 2005

Purpose

This study was conducted to characterize gene expression profile of survival in patients with surgically curable gastric cancer by using an in-house membrane microarray and developing a survival prediction model.

Materials and Methods

Data of cDNA microarrays were obtained from 18 pairs of cancerous and noncancerous gastric tissues. Nine patients who survived > 30 months were identified as good survival, and the other nine, who survived < 12 months, were identified as poor survival. Supervised analysis was performed to identify a gene expression profile by good and poor survival. Semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to confirm the microarray data in 10 patients with sufficient RNA. Using these 10 patients and another 10 patients selected randomly from 40 newly enrolled patients as the training group, the RT-PCR status of the confirmed genes was used for predicting good versus poor survival. Finally, the prediction model was tested in the remaining 30 newly enrolled gastric cancer patients.

Results

A survival prediction model consisting of three genes (CD36, SLAM, PIM-1) was developed. This model could correctly predict poor or good survival in 23 (76.7%) of 30 newly enrolled patients, and yielded a specificity of 80% and a sensitivity of 73.3%. The survival rate of the patients predicted to have good survival was significantly higher than that of those predicted to have poor survival in the test group as a whole (N = 30; P = .00531) and in stage III patients (n = 16; P = .04467).

Conclusion

The semiquantitative RT-PCR gene expression profiling of three genes extracted from microarray study can accurately predict surgery-related outcome in gastric cancer patients.
Phase I Pharmacokinetic Study of S-1 Plus Cisplatin in Patients With Advanced Gastric Carcinoma
Authors: Ajani Jaffer A. , Faust Josephine , Ikeda Kazumasa , Yao James C. , Anbe Hiroshi , Carr Kelli L. , Houghton Michele , Urrea Peter
Published: September 2005

Purpose

The conversion rate of tegafur (a component of S-1) to fluorouracil (FU) differs in Asians and whites because of polymorphic differences in the CYP2A6 gene. S-1 with cisplatin is considered highly active in Japanese gastric cancer patients. Therefore, we initiated a phase I pharmacokinetic study of this combination in our gastric cancer patients.

Patients and Methods

Patients received cisplatin intravenously on day 1 and S-1 orally, twice daily, on days 1 to 21 every 28 days. At level 1, the S-1 dose was 25 mg/m2/dose (50 mg/m2/d), but it was increased by 5 mg/m2/dose for the next level. Cisplatin was administered at 75 mg/m2 (for levels 1 and 2) but was then reduced to 60 mg/m2 (level 1A). At every level, a cohort of three patients, which could be expanded to six patients, was studied. Maximum-tolerated dose (MTD) was determined based on the dose-limiting toxicity (DLT) in the first cycle. Patients with histologic proof of gastric adenocarcinoma and near-normal organ function were studied.

Results

Sixteen patients were enrolled. No DLTs occurred at level 1. However, DLTs occurred at levels 2 and 1A. The area under the curve for FU correlated significantly with DLT (P = .006) and grade 3 to 4 diarrhea (P = .004). Six partial responses were confirmed, including three at the MTD.

Conclusion

At the established MTD of S-1 plus cisplatin, the S-1 dose (50 mg/m2/d for 21 days) is lower in our study than in the Japanese study (80 mg/m2/d for 21 days). A multi-institutional phase II study of this active combination is currently accruing patients.
Roadmap for Developing and Validating Therapeutically Relevant Genomic Classifiers
Authors: Simon Richard
Published: September 2005

Oncologists need improved tools for selecting treatments for individual patients. The development of therapeutically relevant prognostic markers has traditionally been slowed by poor study design, inconsistent findings, and lack of proper validation studies. Microarray expression profiling provides an exciting new technology for relating tumor gene expression to patient outcome, but it also provides increased challenges for translating initial research findings into robust diagnostics that benefit patients and physicians in therapeutic decision making. This article attempts to clarify some of the misconceptions about the development and validation of multigene expression signature classifiers and highlights the steps needed to move genomic signatures into clinical application as therapeutically relevant and robust diagnostics.
Testosterone Patch Increases Sexual Activity and Desire in Surgically Menopausal Women with Hypoactive Sexual Desire Disorder
Authors: Simon James , Braunstein Glenn , Nachtigall Lila , Utian Wulf , Katz Molly , Miller Sam , Waldbaum Arthur , Bouchard Celine , Derzko Christine , Buch Akshay , Rodenberg Cynthia , Lucas Johna , Davis Susan
Published: September 2005

Context: Hypoactive sexual desire disorder (HSDD) is one of the most common sexual problems reported by women, but few studies have been conducted to evaluate treatments for this condition.

Objective: The objective of this study was to evaluate the efficacy and safety of a testosterone patch in surgically menopausal women with HSDD.

Design: The design was a randomized, double-blind, parallel-group, placebo-controlled, 24-wk study (the Intimate SM 1 study).

Setting: The study was performed at private or institutional practices.

Patients: The subjects studied were women, aged 26–70 yr, with HSDD after bilateral salpingo-oophorectomy who were receiving concomitant estrogen therapy. Placebo (n = 279) or testosterone 300 μg/d (n = 283) was administered. There were 19 patients who withdrew due to adverse events in the placebo group and 24 in the 300 μg/d testosterone group.

Intervention: Testosterone (300 μg/d) or placebo patches were applied twice weekly.

Main Outcome Measure(s): The primary end point was the change in the frequency of total satisfying sexual activity at 24 wk. Secondary end points included other sexual functioning end points and safety assessments.

Results: At 24 wk, there was an increase from baseline in the frequency of total satisfying sexual activity of 2.10 episodes/4 wk in the testosterone group, which was significantly greater than the change of 0.98 episodes/4 wk in the placebo group (P = 0.0003). The testosterone group also experienced statistically significant improvements in sexual desire and a decrease in distress. The overall safety profile was similar in both treatment groups.

Conclusion: In the Intimate SM 1 study, the testosterone patch improved sexual function and decreased distress in surgically menopausal women with HSDD and was well tolerated in this trial.
PTPN11 Mutations Are Associated with Mild Growth Hormone Resistance in Individuals with Noonan Syndrome
Authors: Binder G. , Neuer K. , Ranke M. B. , Wittekindt N. E.
Published: September 2005

Context: Noonan syndrome is frequently associated with an unclear disturbance of GH secretion. Half the individuals with Noonan syndrome carry a heterozygous mutation of the nonreceptor-type protein tyrosine phosphatase, Src homology region 2-domain phosphatase-2 (SHP-2), encoded by PTPN11, which has a role in GH receptor signaling.

Objective: The objective of this study was to compare GH secretion and IGF-I/IGF-binding protein-3 (IGFBP-3) levels of the SHP-2 mutation-positive (mut+ group) vs. mutation-negative individuals (mut− group).

Design, Setting, and Patients: All children presenting to us with short stature plus at least three typical anomalies of Noonan syndrome or pulmonic stenosis during the last 5 yr (n = 29; 10 females and 19 males) were recruited. Auxological data, dysmorphic features, and cardiac morphology were documented. Hormone levels were measured by RIA. All coding exons of PTPN11 were sequenced after PCR amplification.

Intervention: A prepubertal subgroup (n = 11) was treated with recombinant human GH (rhGH) to promote growth.

Results: Sequencing yielded 11 different PTPN11 missense mutations in 16 of the 29 patients (55% mut+). Pulmonic stenosis (81 vs. 15%; P = 0.0007) and septal defects (63 vs. 15%; P = 0.02) were more frequently found in the mut+ group, whereas minor anomalies, cryptorchidism, and learning disabilities were as frequent in the mut+ group as in the mut− group. The mut+ group was younger at presentation (mean ± sd, 5.1 ± 2.7 vs. 10.3 ± 5.2 yr; P = 0.002), but not significantly shorter [−3.15 ± 0.92 vs. −3.01 ± 1.35 height sd score (SDS)]. IGF-I levels (−2.03 ± 0.69 vs. −1.13 ± 0.89 SDS; P = 0.005) and IGFBP-3 levels (−0.92 ± 1.26 vs. 0.40 ± 1.08 SDS; P = 0.006) were significantly lower in the mut+ group. In contrast, GH levels showed a tendency to be higher in the mut+ group during spontaneous secretion at night and arginine stimulation (P ≥ 0.075, not significant). The mean change in height SDS after 1 yr of rhGH therapy (0.043 mg/kg·d) was +0.66 ± 0.21 in the mut+ group (n = 8), but +1.26 ± 0.36 in the mut− group (n = 3; P = 0.007).

Conclusions: Our data suggest that SHP-2 mutations in Noonan syndrome cause mild GH resistance by a postreceptor signaling defect, which seems to be partially compensated for by elevated GH secretion. This defect may contribute to the short stature phenotype in children with SHP-2 mutations and their relatively poor response to rhGH.
The leading edge is a lipid diffusion barrier
Authors: Weisswange Ina , Bretschneider Till , Anderson Kurt I.
Published: September 2005

Actin polymerization drives many cellular events, including endocytosis, pathogen rocketing, and cell spreading. Force generation and polymerization regulation are intimately linked where an actin meshwork attaches to, and pushes against, an interface. We reasoned that interaction with actin filament plus-ends might stabilize the position of components within the plasma membrane at the leading edge, thereby slowing the diffusion of lipids within the bilayer where filament growth occurs. To test this hypothesis we focally labeled the outer membrane leaflet of migrating keratocytes and compared the initial diffusion of carbocyanine dyes in the dorsal and ventral lamellipodium membranes using sequential TIRF and epi-fluorescent imaging. Global diffusion analysis shows that lateral mobility of lipids in the outer membrane leaflet is blocked at the leading edge during protrusion. Cytochalasin treatment abolished this diffusion barrier, but we found no evidence to support the involvement of membrane microdomains. Our results demonstrate the immobilization of membrane components at the leading edge, and suggest that interaction between actin filaments and the plasma membrane is mediated by densely packed molecular complexes. We propose that actin polymerization traps regulatory proteins at the leading edge in a positive-feedback loop.
5-Azacytidine and Decitabine Monotherapies of Myelodysplastic Disorders
Authors: Kuykendall Jim R
Published: September 2005

OBJECTIVE:

To review and differentiate the pharmacology, toxicology, pharmacokinetics, and results of major clinical trials of 5-azacytidine (5-AzaC) and 5-aza-2'-deoxycytidine (decitabine) therapy of myelodysplastic disorders.

DATA SOURCES:

A PubMed/MEDLINE search was conducted (1966–October 2004) using the following terms: DNA methylation, myelodysplastic disorders, 5-azacytidine, and 5-aza-2'-deoxycytidine (decitabine). Additional data sources included bibliographies from identified articles and manufacturer information.

STUDY SELECTION AND DATA EXTRACTION:

Clinical trials for the treatment of various malignancies by hypomethylating agents were selected from data sources. All published, major clinical trials evaluating 5-AzaC or decitabine in myelodysplastic disorders and transformed myeloid leukemia treatment were included.

DATA SYNTHESIS:

Myelodysplastic disorders are a group of bone marrow stem cell hyperplasias and dysplasias that result in ineffective hematopoiesis. Myelodysplastic disorders and transformed leukemia have poor prognosis and minimal response to chemotherapy. DNA hypomethylating agents have been shown to improve overall response rates (increased neutrophil, leukocyte, and platelet counts), time to leukemic progression, and quality of life compared with supportive therapy. The incidence of the most common adverse effects (nausea, vomiting, myelosuppression) can be reduced by low-dose, continuous, or extended-interval infusion.

CONCLUSIONS:

Since appropriate dosing schedules of decitabine are being investigated, comparison of the clinical effectiveness of 5-AzaC and decitabine would be premature at this time. DNA hypomethylating agents show promise as monotherapies of myelodysplastic disorders and transformed leukemia and may be useful as a component of combination chemotherapy of various malignancies.
Successful Treatment of Corynebacterium striatum Endocarditis with Daptomycin plus Rifampin
Authors: Shah Monica , Murillo Jeremias L
Published: September 2005

OBJECTIVE:

To report a case of Corynebacterium striatum endocarditis that was treated successfully with daptomycin plus rifampin following an unsuccessful attempt at vancomycin desensitization and failure of linezolid therapy.

CASE SUMMARY:

A 46-year-old woman with hemodialysis-dependent chronic renal failure was admitted for a graft-related infection. She presented with C. striatum endocarditis that was treated with daptomycin plus rifampin due to a history of allergies to vancomycin and β-lactam antibiotics and failure of linezolid therapy. The patient received daptomycin and rifampin for a total of 6 weeks. Three months after completion of treatment, no recurrence of endocarditis was evident.

DISCUSSION:

Daptomycin is a lipopeptide antibiotic, with rapid bactericidal activity. It has demonstrated efficacy in animal models of staphylococcal, streptococcal, and enterococcal endocarditis. Case reports of its activity in methicillin-resistant Staphylococcus aureus endocarditis have also been documented.

CONCLUSIONS:

Daptomycin, which has shown in vitro activity against C. striatum, may be a viable treatment option for patients with C. striatum endocarditis who are either allergic or refractory to traditional antibiotics.
Structural Covariance in the Human Cortex
Authors: Mechelli Andrea , Friston Karl J. , Frackowiak Richard S. , Price Cathy J.
Published: September 2005

The morphology of the human cortex varies remarkably across individuals, regardless of overall brain size. It is currently unclear whether related cortical regions covary in gray matter density, as a result of mutually trophic influences or common experience-related plasticity. We acquired a structural magnetic resonance imaging scan from 172 subjects and extracted the regional gray matter densities from 12 readily identifiable regions of interest involved in sensorimotor or higher-order cognitive functions. We then used these values to predict regional densities in the remaining areas of the cortex, using voxel-based morphometry. This revealed patterns of positive and negative covariance that provide insight into the topographical organization of multiple cortical regions. We report that the gray matter density of a region is a good predictor of the density of the homotopic region in the contralateral hemisphere, with the striking exception of primary visual cortex. Whereas some regions express patterns of regional covariance that are mirror symmetrical relative to the interhemispheric fissure, other regions express asymmetric patterns of regional covariance. Finally, patterns of covariance are remarkably consistent between males and females, with the exception of the left amygdala, which is positively associated with the left and right anterior inferior temporal cortex in males and with the right angular gyrus in females. Our study establishes that the density of different cortical regions is coordinated within an individual. The coordinated variations we report are likely to be determined by both genetic and environmental factors and may be the basis for differences in individual behavior.
Genotype-Dependent Activity of Tryptophan Hydroxylase-2 Determines the Response to Citalopram in a Mouse Model of Depression
Authors: Cervo Luigi , Canetta Alessandro , Calcagno Eleonora , Burbassi Silvia , Sacchetti Giuseppina , Caccia Silvio , Fracasso Claudia , Albani Diego , Forloni Gianluigi , Invernizzi Roberto W.
Published: September 2005

Polymorphism of tryptophan hydroxylase, the rate-limiting enzyme in the synthesis of brain serotonin (5-HT), is associated with less synthesis of brain 5-HT in DBA/2J and BALB/c than in C57BL/6J and 129/Sv mice. We selected the forced swimming test, a mouse model used to assess the antidepressant potential of drugs, and neurochemical techniques to study strain differences in the response to citalopram, a selective 5-HT reuptake inhibitor. Citalopram reduced immobility time in C57BL/6J and 129/Sv mice but had no such effect in DBA/2J and BALB/c mice. The drug reduced accumulation of 5-hydroxytryptophan (5-HTP), an indicator of 5-HT synthesis, in C57BL/6J and 129/Sv mice but much less in DBA/2J and BALB/c mice. Pretreatment with tryptophan raised 5-HTP accumulation and reinstated the antidepressant-like effect of citalopram in DBA/2J and BALB/c mice, whereas pharmacological inhibition of 5-HT synthesis prevented the effect of citalopram in C57BL/6J and 129/Sv mice. Because there were no strain differences in catecholamine synthesis, locomotor activity, and brain levels of citalopram at the end of the behavioral test, the results suggest that the failure of citalopram to reduce immobility time in DBA/2J and BALB/c mice is attributable to genotype-dependent impairment of 5-HT synthesis. Interstrain comparisons could probably be a useful strategy for understanding the mechanisms underlying the response to selective serotonin reuptake inhibitors.
Synergistic Effect of Combined Temporal and Spatial Expectations on Visual Attention
Authors: Doherty Joanna R. , Rao Anling , Mesulam M. Marsel , Nobre Anna C.
Published: September 2005

We developed a naturalistic behavioral task to investigate the influence of spatial and temporal expectations on attentional orienting to moving targets. In this task, the movement of an object before its disappearance under an occluding barrier generated expectations concerning the location and/or time of its reappearance. Four different trial types were intermixed, each inducing a different state of expectation: no expectation, only spatial expectation about the location of reappearance, only temporal expectation about the moment of reappearance, and combined spatial and temporal expectation. The behavioral validity of the task was shown by the fact that all expectation conditions produced significantly shorter reaction times than the control state of no expectation. Spatial attention modulated early perceptual analysis in extrastriate areas, as demonstrated by significant enhancement of the visual P1 component. Temporal attention alone had no effect on P1 but instead modulated response-specific components. However, when spatial and temporal attention were combined, the enhancement of perceptual processing was significantly augmented, leading to a greater enhancement of the P1 component than by spatial attention alone. Perceptual analysis reflected by the P1 component correlated significantly with reaction times. In summary, event-related potentials revealed the presence of individual modulatory effects attributable to spatial and temporal expectation as well as synergistic effects indicative of an interaction of the two. This synergistic effect is likely to play a critical role in directing attention to the reappearance of a temporarily occluded moving target, a process of obvious importance in everyday situations.
Multiple Object Response Normalization in Monkey Inferotemporal Cortex
Authors: Zoccolan Davide , Cox David D. , DiCarlo James J.
Published: September 2005

The highest stages of the visual ventral pathway are commonly assumed to provide robust representation of object identity by disregarding confounding factors such as object position, size, illumination, and the presence of other objects (clutter). However, whereas neuronal responses in monkey inferotemporal cortex (IT) can show robust tolerance to position and size changes, previous work shows that responses to preferred objects are usually reduced by the presence of nonpreferred objects. More broadly, we do not yet understand multiple object representation in IT. In this study, we systematically examined IT responses to pairs and triplets of objects in three passively viewing monkeys across a broad range of object effectiveness. We found that, at least under these limited clutter conditions, a large fraction of the response of each IT neuron to multiple objects is reliably predicted as the average of its responses to the constituent objects in isolation. That is, multiple object responses depend primarily on the relative effectiveness of the constituent objects, regardless of object identity. This average effect becomes virtually perfect when populations of IT neurons are pooled. Furthermore, the average effect cannot simply be explained by attentional shifts but behaves as a primarily feedforward response property. Together, our observations are most consistent with mechanistic models in which IT neuronal outputs are normalized by summed synaptic drive into IT or spiking activity within IT and suggest that normalization mechanisms previously revealed at earlier visual areas are operating throughout the ventral visual stream.
Developmental Activation of Calmodulin-Dependent Facilitation of Cerebellar P-Type Ca2+Current
Authors: Chaudhuri Dipayan , Alseikhan Badr A. , Chang Siao Yun , Soong Tuck Wah , Yue David T.
Published: September 2005

P-type (CaV2.1) Ca2+channels are a central conduit of neuronal Ca2+entry, so their Ca2+feedback regulation promises widespread neurobiological impact. Heterologous expression of recombinant CaV2.1 channels demonstrates that the Ca2+sensor calmodulin can trigger Ca2+-dependent facilitation (CDF) of channel opening. This facilitation occurs when local Ca2+influx through individual channels selectively activates the C-terminal lobe of calmodulin. In neurons, however, such calmodulin-mediated processes have yet to be detected, and CDF of native P-type current has thus far appeared different, arguably triggered by other Ca2+sensing molecules. Here, in cerebellar Purkinje somata abundant with prototypic P-type channels, we find that the C-terminal lobe of calmodulin does produce CDF, and such facilitation augments Ca2+entry during stimulation by repetitive action-potential and complex-spike waveforms. Beyond recapitulating key features of recombinant channels, these neurons exhibit an additional modulatory dimension: developmental upregulation of CDF during postnatal week 2. This phenomenon reflects increasing somatic expression of CaV2.1 splice variants that manifest CDF and progressive dendritic targeting of variants lacking CDF. Calmodulin-triggered facilitation is thus fundamental to native CaV2.1 and rapidly enhanced during early development.
Olfactory Bulb External Tufted Cells Are Synchronized by Multiple Intraglomerular Mechanisms
Authors: Hayar Abdallah , Shipley Michael T. , Ennis Matthew
Published: September 2005

In rat olfactory bulb slices, external tufted (ET) cells spontaneously generate spike bursts. Only ET cells affiliated with the same glomerulus exhibit significant synchronous activity, suggesting that synchrony results mainly from intraglomerular interactions. The intraglomerular mechanisms underlying their synchrony are unknown. Using dual extracellular and patch-clamp recordings from ET cell pairs of the same glomerulus, we found that the bursting of ET cells is synchronized by several mechanisms. First, ET cell pairs of the same glomerulus receive spontaneous synchronous fast excitatory synaptic input that can also be evoked by olfactory nerve stimulation. Second, they exhibit correlated spontaneous slow excitatory synaptic currents that can also be evoked by stimulation of the external plexiform layer. These slow currents may reflect the repetitive release of glutamate via spillover from the dendritic tufts of other ET or mitral/tufted cells affiliated with the same glomerulus. Third, ET cells exhibit correlated bursts of inhibitory synaptic activity immediately after the synchronous fast excitatory input. These bursts of IPSCs were eliminated by CNQX and may therefore reflect correlated feedback inhibition from periglomerular cells that are driven by ET cell spike bursts. Fourth, in the presence of fast synaptic blockers, ET cell pairs exhibit synchronous slow membrane current oscillations associated with rhythmic spikelets, which were sensitive to the gap junction blocker carbenoxolone. These findings suggest that coordinated synaptic transmission and gap junction coupling synchronize the spontaneous bursting of ET cells of the same glomerulus.
Amygdalar and Prefrontal Pathways to the Lateral Hypothalamus Are Activated by a Learned Cue That Stimulates Eating
Authors: Petrovich Gorica D. , Holland Peter C. , Gallagher Michela
Published: September 2005

Experimental animals that are trained to associate a cue with food consumption when hunger prevails will subsequently consume a greater amount of food when that cue is presented under conditions of satiety. Previously, we showed that this phenomenon of conditioned potentiation of feeding is abolished by a neurotoxic lesion that encompasses the basolateral (BL), basomedial (BM), and lateral (LA) nuclei of the amygdala (AMY) and by disconnection of this region and lateral hypothalamus (LHA). Here, we combined immediate-early gene (IEG) and tract-tracing methods to map functional AMY–LHA circuitry that is engaged when potentiated feeding is produced by pavlovian conditioning. Sated rats were assessed for food consumption in the presence of a cue that was paired previously with food (CS+), or in the presence of another cue that was never paired with food (CS–), in two consecutive tests temporally arranged for activation of the effector IEGsArc(activity-regulated cytoskeletal protein) andHomer 1a. We examined the selective induction of the IEGs by tests with CS+ or CS– presentations in AMY neurons that project to LHA, as identified with the retrograde tracer FluoroGold. Using the same labeling methods, we also examined neurons in several other forebrain regions, including the prefrontal cortex and nucleus accumbens, that receive strong inputs from BL/BM/LA nuclei and, in turn, innervate the LHA. Our results indicate that a cue that has acquired the ability to promote eating in sated rats (CS+) strongly activates a functional network formed by direct pathways from the BL/BM and orbitomedial prefrontal cortex to the LHA.
Differential Amplification of Murine Bipotent Megakaryocytic/Erythroid Progenitor and Precursor Cells During Recovery from Acute and Chronic Erythroid Stress
Authors: Sanchez Massimo , Weissman Irving L. , Pallavicini Maria , Valeri Mauro , Guglielmelli Paola , Vannucchi Alessandro Maria , Migliaccio Giovanni , Migliaccio Anna Rita
Published: September 2005

Two murine bipotent erythroid/megakaryocytic cells, the progenitor (MEP) and precursor (PEM) cells, recently have been identified on the basis of the phenotypes of linnegc-kitposSca-1neg CD16/CD32lowCD34low and TER119pos4A5pos or 2D5pos, respectively. However, the functional relationship between these two subpopulations and their placement in the hemopoietic hierarchy is incompletely understood. We compared the biological properties of these subpopulations in marrow and spleen of mice with and without acute or chronic erythroid stress. MEP cells, but not PEM cells, express c-kit, respond to stem cell factor in vitro, and form spleen colonies in vivo. PEM cells comprise up to 50%–70% of the cells in BFU-E–derived colonies but are not present among the progeny of purified MEP cells cultured under erythroid and megakaryocytic permissive conditions. PEM cells increase 10- to 20-fold under acute and chronic stress, whereas MEP cell increases (21%–84%) are observed only in acutely stressed animals. These data suggest that MEP and PEM cells represent distinct cell populations that may exist in an upstream-downstream differentiation relationship under conditions of stress. Whereas the dynamics of both populations are altered by stress induction, the differential response to acute and chronic stress suggests different regulatory mechanisms. A model describing the relationship between MEP, PEM, and common myeloid progenitor cells is presented.
Management implications of coastal change in Suffolk, UK
Authors: Pontee N. I.
Published: September 2005

Rising sea levels throughout the Holocene have contributed to a predominance of erosion around many parts of the UK coastline. This paper considers three sites on the Suffolk coast where human activities have been affected by both erosion and accretion. A simple conceptual model is presented in which the erosion and alongshore transport of material leads to the partial or complete blockage of coastal inlets down-drift. This model places meso-scale changes within a macro-scale setting and integrates historical trends with contemporary beach responses and a knowledge of coastal dynamics, in order to make an assessment of future evolutionary trends. At some sites future coastal changes are likely to represent a continuation of past trends; however, at others there may be a shift to new system domains in the future. The likely impacts of these future changes for coastal settlements are compared with those that have been accommodated by coastal communities in the past. It is suggested that in the future coastal management on this stretch of coast needs to embrace natural processes, rather than working against them. However, the successful implementation of such a policy is likely to be dependent on increasing public awareness in terms of the impacts of both past and future coastal changes.
High‐Throughput Real‐Time Quantitative Reverse Transcription PCR
Authors: Bookout Angie L. , Cummins Carolyn L. , Mangelsdorf David J.
Published: August 2005

Extensive detail on the application of the real‐time quantitative polymerase chain reaction (QPCR) for the analysis of gene expression is provided in this unit. The protocols are designed for high‐throughput, 384‐well‐format instruments, such as the Applied Biosystems 7900HT, but may be modified to suit any real‐time PCR instrument. QPCR primer and probe design and validation are discussed, and three relative quantitation methods are described: the standard curve method, the efficiency‐corrected ΔCt method, and the comparative cycle time, or ΔCt method.
Regulation of Transgene Expression Using Tetracycline
Authors: Gulick James , Robbins Jeffrey
Published: August 2005

Transgenesis has proven useful in creating animal models that mimic certain disease states, providing a mechanistic approach for understanding the underlying disease mechanisms at the molecular and cellular levels. With traditional transgenics, the gene of interest is cloned behind a promoter that has the desired expression pattern, allowing the gene to be expressed in those tissues at the developmental times that the promoter is active. In order to more precisely control gene expression both in vitro and in vivo, inducible systems that use pharmacologic intervention to control transgene expression have been developed (UNIT 16.14). As previously described, the system consists of two components, an activator that is regulated by tetracycline and a responder that is dependent upon the activator. Both limbs of the system will be discussed in the context of inducible and reversible transgene expression that is cell type– or organ‐specific, with particular attention paid to the cardiovascular system.
Establishment and Culture of Human Skin Fibroblasts
Authors: Villegas Jacob , McPhaul Michael
Published: August 2005

The establishment of skin fibroblast strains provides a vehicle by which biochemical and genetic studies may be applied. In addition to providing genetic material to study the basis of disease, fibroblast cell lines established from skin biopsies may provide the investigator with a model in which to study specific disease states or normal physiology. This unit provides methods for the biopsy, establishment, and culture maintenance of skin fibroblasts to be used in further scientific study.
Flow Cytometric Screening for the HLA‐B27 Antigen on Peripheral Blood Lymphocytes
Authors: Levering Wilfried H.B.M. , Sintnicolaas Kees , Wind Henk , Hooijkaas Herbert , Gratama Jan W.
Published: August 2005

HLA‐B27 is common to the entire group of seronegative spondyloarthropathies, and assessment of HLA‐B27 is of diagnostic importance if any of these diseases are considered. Among the alternatives to traditional typing by the complement‐dependent cytotoxicity assay, flow cytometric HLA‐B27 screening is most widely used in general diagnostic laboratories, as it is simple, rapid, and cost effective. This unit describes screening for HLA‐B27 on peripheral blood lymphocytes using more than one HLA‐B27 monoclonal antibody to detect possible cross‐reactivity with non‐HLA‐B27 antigens. Screening is hampered by the lack of true monospecific anti‐HLA‐B27 monoclonal antibodies. Cross‐reactivities of anti‐HLA‐B27 with other HLA‐B antigens have been reported. The authors recommend use of GS145.2 and FD705 antibodies, as this combination avoids most false‐positive conclusions. Lyse‐and‐wash sample processing is employed. A multiparameter flow methodology is applied. Three to four parameters–forward scatter, side scatter, HLA‐B27 expression, and, in some cases CD3 or B7 expression–are acquired.
Mixing effects on performance and stability of low‐density polyethylene reactors
Authors: Wells Gary J. , Ray W. Harmon
Published: August 2005

Imperfect initiator mixing greatly affects the stability and efficiency of low density polyethylene (LDPE) autoclave reactors. A combined simulation technique utilizing compartment models and computational fluid dynamics extends previous work in the literature by providing a physically detailed picture of imperfect mixing. Analysis indicates that the effective volume for chain propagation in the autoclave reactor can expand and contract in a continuous fashion as operating conditions change. As mixing becomes poor, the effective reactive volume decreases, causing a reduction in initiator efficiency, but an expansion in the stable operation region. Examples demonstrate that accurate prediction of the effective reaction volume is crucial for predicting LDPE autoclave reactor behavior. A new mixing model that represents the feed plume by a series of interconnected tanks with geometrically increasing volumes provides a favorable tradeoff between accuracy and model complexity. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Users want more sophisticated search assistants: Results of a task‐based evaluation
Authors: Kruschwitz Udo , Al‐Bakour Hala
Published: August 2005

The Web provides a massive knowledge source, as do intranets and other electronic document collections. However, much of that knowledge is encoded implicitly and cannot be applied directly without processing into some more appropriate structures. Searching, browsing, question answering, for example, could all benefit from domain‐specific knowledge contained in the documents, and in applications such as simple search we do not actually need very “deep” knowledge structures such as ontologies, but we can get a long way with a model of the domain that consists of term hierarchies. We combine domain knowledge automatically acquired by exploiting the documents' markup structure with knowledge extracted on the fly to assist a user with ad hoc search requests. Such a search system can suggest query modification options derived from the actual data and thus guide a user through the space of documents. This article gives a detailed account of a task‐based evaluation that compares a search system that uses the outlined domain knowledge with a standard search system. We found that users do use the query modification suggestions proposed by the system. The main conclusion we can draw from this evaluation, however, is that users prefer a system that can suggest query modifications over a standard search engine, which simply presents a ranked list of documents. Most interestingly, we observe this user preference despite the fact that the baseline system even performs slightly better under certain criteria.
Comparison of properties on non‐protected fluid room temperature phosphorescence of some tetra‐ring aromatic hydrocarbons
Authors: Zhang Zhong‐Xiao , Li Long‐Di , Wu Ya‐Lan , Liu Jia‐Ming
Published: August 2005

A comparative study of the photoluminescence properties of three kinds of tetra‐ring aromatic hydrocarbon (1sodium pyrenesulphonate, benz[α]anthracene and chrysene) solution in the absence of any protecting medium is decribed. It was found that a room temperature phosphorescence signal with different intensities can be induced for these solutions, using only TlNO3 or KI as a heavy atom perturber (HAP) and Na2SO3 as a deoxygenator. An appropriate amount of organic solvent added to the systems of pyrene, benz[α]anthracene and chrysene is necessary for increasing the solubility and phosphorescence intensity, and the preferable solvent is acetonitrile. For the pyrene, pyrenesulphonate and chrysene systems, a delayed excimer fluorescence accompanied with the room temperature phosphorescence (RTP) emission can be observed, but that for benz[α]anthracene cannot. The ratio of delayed excimer fluorescence and phosphorescence signals for pyrene, pyrenesulphonate and chrysene systems can be controlled by adjusting the concentration of luminophor, kinds and amount of both organic solvents and HAP. Under the optimal conditions, the RTP signals are proportional to the concentration of the four aromatic hydrocarbons, which means that the RTP properties of the four tetra‐ring aromatic hydrocarbons can be used for quantitative analysis. Copyright © 2005 John Wiley & Sons, Ltd.
Rapid screening method for simultaneous determination of four polycyclic aromatic hydrocarbons in water samples by derivative non‐linear variable‐angle synchronous fluorescence spectrometry
Authors: Lin Dan‐Li , Zou Zhe‐Xiang , He Li‐Fang , Li Yao‐Qun
Published: August 2005

Derivative non‐linear variable‐angle synchronous fluorescence spectroscopy (D‐NLVASFS) has been developed to improve the selectivity of the fluorescence measurement without loss of sensitivity. We report a simple screening approach for the rapid and simultaneous determination of 1,2.5,6‐dibenzoanthracene (DBA), 2,3‐benzofluorene (BF), pyrene (Pyr) and 3,4‐benzopyrene (BaP) in a mixture by using first‐derivative NLVASFS. The method is efficient, fast and straightforward, and the measurement was simply based on a single spectrum via a single spectral scanning of a sample. The linear ranges 0.005–0.30, 0.02–0.30, 0.02–0.40 and 0.005–1.0 µg/mL and the detection limits 0.08, 1.14, 1.64 and 0.12 ng/mL are obtained for DBA, BF, Pyr and BaP, respectively. The method was applied to water samples spiked with the four polycyclic aromatic hydrocarbons (PAHs), with mean recoveries of 103.0% (SD 5.9%) for DBA, 96.4% (SD 4.2%) for BF, 96.2% (SD 4.0%) for Pyr and 98.2% (SD 3.0%) for BaP. Copyright © 2005 John Wiley & Sons, Ltd.
Post‐chemiluminescence behaviour of Ni2+, Mg2+, Cd2+ and Zn2+ in the potassium ferricyanide–luminol reaction
Authors: Feng Na , Lu Jiuru , He Yunhua , Du Jianxiu
Published: August 2005

A new chemiluminescence (CL) reaction was observed when Ni2+, Mg2+, Cd2+ or Zn2+ was injected into the reaction mixture after the finish of the CL reaction of alkaline luminol and potassium ferricyanide. This reaction is described as a post‐chemiluminescence (PCL) reaction. The possible mechanism for the PCL was proposed based on studies of the CL kinetic characteristic and the CL spectra. The experimental conditions of the CL reactions were optimized and the feasibility of using the reaction to analyse these metal ions was evaluated. The PCL reaction method operates in the ranges: 1 × 10−7–8 × 10−6 g/L Ni2+; 3 × 10−6–2 × 10−4 g/L Mg2+; 8 × 10−7–1 × 10−4 g/L Cd2+; and 2 × 10−4–2 × 10−3 g/L Zn2+, with detection limits of 4 × 10−8 g/mL, 1 × 10−6 g/mL, 3 × 10−7 g/mL, 8 × 10−5 g/mL, respectively. Copyright © 2005 John Wiley & Sons, Ltd.
Flow‐injection electrogenerated chemiluminescence determination of fluoroquinolones based on its sensitizing effect
Authors: Ma Hongyan , Zheng Xingwang , Zhang Zhujun
Published: August 2005

A simple and sensitive flow‐injection electrogenerated chemiluminescence (ECL) method for the determination of fluoroquinolones was developed. The method is based on the sensitizing effect of fluoroquinolones on the weak ECL signal of electrochemical oxidation of luminol on the surface of the platinum flake electrode in the medium of 0.1 mol/L Na2CO3–NaHCO3. At the optimum experimental conditions, the relative ECL intensity increased linearly with increasing fluoroquinolones concentration, in the ranges 1.0 × 10−8–2.0 × 10−4 g/mL for norfloxacin, 5.0 × 10−9–6.0 × 10−6 g/mL for oxfloxacin, 2.0 × 10−8–1.4 × 10−5 g/mL for ciprofloxacin, 1.0 × 10−8–1.4 × 10−5 g/mL for pefloxacin, and 1.0 × 10−9–1.0 × 10−5 g/mL for enoxacin, with detection limits of 4.0 × 10−9 g/mL, 2.0 × 10−9 g/mL, 1.0 × 10−8 g/mL, 8.0 × 10−9 g/mL, and 8.0 × 10−10 g/mL, respectively. The relative standard deviations were all less than 2.5% for the determination of 2.0 × 10−6 g/mL fluoroquinolones (n = 11). The method was used to determine these medicines in pharmaceutical samples with satisfactory results. Copyright © 2005 John Wiley & Sons, Ltd.