Ultrahigh Field fMRI Reveals Different Roles of the Temporal and Frontoparietal Cortices in Subjective Awareness

A central question in consciousness theories is whether one is dealing with a dichotomous ("all-or-none") or a gradual phenomenon. In this 7T fMRI study, we investigated whether dichotomy or gradualness in fact depends on the brain region associated with perceptual awareness reports. Both male and female human subjects performed an emotion discrimination task (fear vs neutral bodies) presented under continuous flash suppression with trial-based perceptual awareness measures. Behaviorally, recognition sensitivity increased linearly with increased stimuli awareness and was at chance level during perceptual unawareness. Physiologically, threat stimuli triggered a slower heart rate than neutral ones during "almost clear" stimulus experience, indicating freezing behavior. Brain results showed that activity in the occipitotemporal, parietal, and frontal regions as well as in the amygdala increased with increased stimulus awareness while early visual areas showed the opposite pattern. The relationship between temporal area activity and perceptual awareness best fitted a gradual model while the activity in frontoparietal areas fitted a dichotomous model. Furthermore, our findings illustrate that specific experimental decisions, such as stimulus type or the approach used to evaluate awareness, play pivotal roles in consciousness studies and warrant careful consideration.

Early visual experience refines the retinotopic organization within and across visual cortical regions

Early visual areas are retinotopically organized in human and non-human primates. Population receptive field (pRF) size increases with eccentricity and from lower- to higher-level visual areas. Furthermore, the cortical magnification factor (CMF), a measure of how much cortical space is devoted to each degree of visual angle, is typically larger for foveal as opposed to peripheral regions of the visual field. Whether this fine-scale organization within and across visual areas depends on early visual experience has yet been unknown. Here, we employed 7T functional magnetic resonance imaging pRF mapping to assess the retinotopic organization of early visual regions (i.e., V1, V2, and V3) in eight sight recovery individuals with a history of congenital blindness until a maximum of 4 years of age. Compared with sighted controls, foveal pRF sizes in these individuals were larger, and pRF sizes did not show the typical increase with eccentricity and down the visual cortical processing stream (V1-V2-V3). Cortical magnification was overall diminished and decreased less from foveal to parafoveal visual field locations. Furthermore, cortical magnification correlated with visual acuity in sight recovery individuals. The results of this study suggest that early visual experience is essential for refining a presumably innate prototypical retinotopic organization in humans within and across visual areas, which seems to be crucial for acquiring full visual capabilities.

Does the visual word form area split in bilingual readers? A millimeter-scale 7-T fMRI study

In expert readers, a brain region known as the visual word form area (VWFA) is highly sensitive to written words, exhibiting a posterior-to-anterior gradient of increasing sensitivity to orthographic stimuli whose statistics match those of real words. Using high-resolution 7-tesla functional magnetic resonance imaging (fMRI), we ask whether, in bilingual readers, distinct cortical patches specialize for different languages. In 21 English-French bilinguals, unsmoothed 1.2-millimeters fMRI revealed that the VWFA is actually composed of several small cortical patches highly selective for reading, with a posterior-to-anterior word-similarity gradient, but with near-complete overlap between the two languages. In 10 English-Chinese bilinguals, however, while most word-specific patches exhibited similar reading specificity and word-similarity gradients for reading in Chinese and English, additional patches responded specifically to Chinese writing and, unexpectedly, to faces. Our results show that the acquisition of multiple writing systems can indeed tune the visual cortex differently in bilinguals, sometimes leading to the emergence of cortical patches specialized for a single language.

[Efficacy analysis of high-sensitivity troponin I concentration and its changes in the diagnosis of acute myocardial infarction]

Objective: To explore the feasibility and accuracy of 0-1 h high sensitivity cardiac troponin I (hs-cTnI) concentration and its changes in judging non-ST segment elevation myocardial infarction (NSTEMI), and to investigate the feasibility of a simplified process. Methods: Patients with acute chest pain and suspected NSTEMI who were admitted to the emergency department of Fuwai Hospital, the First Affiliated Hospital of Sun Yat-sen University and Nanjing First Hospital from January 2017 to September 2020 were selected. Hs-cTnI test was carried out for the selected patients at the time of visit (0 h) and 1 h after visit. According to the 0-1 h hs-cTnI diagnostic process and threshold standard recommended by European Society of Cardiology (ESC) guidelines in 2015, the laboratory adjudication was determined. Cardiologists who did not participate in the project design and did not know the results of hs-cTnI test performed the clinical judgment according to the routine diagnosis and treatment process of emergency department. Taking clinical judgment as the gold standard, the diagnostic efficacy of 0-1 h hs-cTnI concentration and its change recommended by the guidelines for judging NSTEMI in Chinese population was analyzed. The guide process was simplified. Under the condition of not considering the time of chest pain, the guideline threshold was used for test and judgement, and the diagnostic efficacy of the simplified process was evaluated. Results: A total of 1 534 patients were enrolled in the study, aged (62±12) years and 952 (62.1%) patients were male. Among them, 402 patients (26.2%) were clinically diagnosed as NSTEMI and 1 132 patients (73.8%) were diagnosed as non-NSTEMI. According to the diagnosis and determination process recommended by the guidelines, NSTEMI was excluded in 672 patients (42.8%), and 464 patients (30.2%) were diagnosed as NSTEMI. The consistency rate with clinical determination reached 92.4% (1 050/1 136), the sensitivity of excluding diagnosis was 99.5% (95%CI: 98.0%-99.9%), the negative predictive value was 99.7% (95%CI: 98.8%-99.9%), and the negative likelihood ratio was 0.008 (95%CI: 0.002-0.335). The diagnostic specificity was 92.6% (95%CI: 90.9%-94.0%), the positive predictive value was 81.9% (95%CI: 78.0%-85.2%), and the positive likelihood ratio was 12.739 (95%CI: 10.356-15.670). According to the simplified process, NSTEMI was excluded in 675 patients (44.0%), and 463 patients (30.2%) were diagnosed as NSTEMI. The consistency rate with clinical judgment was 92.4% (1 051/1 138), the sensitivity of exclusion diagnosis was 99.3% (95%CI: 97.6%-99.8%), the negative predictive value was 99.6% (95%CI: 98.6%-99.9%), and the negative likelihood ratio was 0.012 (95%CI: 0.004-0.389). The diagnostic specificity was 92.6% (95%CI: 90.9%-94.0%), the positive predictive value was 81.9% (95%CI: 78.0%-85.2%), and the positive likelihood ratio was 12.705 (95%CI: 10.328-15.630). There was no significant difference in diagnostic efficacy between the simplified process and the recommended process (all P>0.05). Conclusion: The diagnostic process for judging NSTEMI according to the 0-1 h hs-cTnI concentration and its change criteria recommended by the 2015 ESC guidelines is applicable in the Chinese population and remains highly accurate in judging NSTEMI without considering the duration of chest pain at the time of presentation.

Inconsistencies in atlas-based volumetric measures of the human nucleus basalis of Meynert: A need for high-resolution alternatives

The nucleus basalis of Meynert (nbM) is the major source of cortical acetylcholine (ACh) and has been related to cognitive processes and to neurological disorders. However, spatially delineating the human nbM in MRI studies remains challenging. Due to the absence of a functional localiser for the human nbM, studies to date have localised it using nearby neuroanatomical landmarks or using probabilistic atlases. To understand the feasibility of MRI of the nbM we set our four goals; our first goal was to review current human nbM region-of-interest (ROI) selection protocols used in MRI studies, which we found have reported highly variable nbM volume estimates. Our next goal was to quantify and discuss the limitations of existing atlas-based volumetry of nbM. We found that the identified ROI volume depends heavily on the atlas used and on the probabilistic threshold set. In addition, we found large disparities even for data/studies using the same atlas and threshold. To test whether spatial resolution contributes to volume variability, as our third goal, we developed a novel nbM mask based on the normalized BigBrain dataset. We found that as long as the spatial resolution of the target data was 1.3 mm isotropic or above, our novel nbM mask offered realistic and stable volume estimates. Finally, as our last goal we tried to discern nbM using publicly available and novel high resolution structural MRI ex vivo MRI datasets. We find that, using an optimised 9.4T quantitative T₂^⁎ ex vivo dataset, the nbM can be visualised using MRI. We conclude caution is needed when applying the current methods of mapping nbM, especially for high resolution MRI data. Direct imaging of the nbM appears feasible and would eliminate the problems we identify, although further development is required to allow such imaging using standard (f)MRI scanning.

Acquired Prosopagnosia with Structurally Intact and Functional Fusiform Face Area and with Face Identity-Specific Configuration Processing Deficits

Prosopagnosia or loss of face perception and recognition is still poorly understood and rare single cases of acquired prosopagnosia can provide a unique window on the behavioural and brain basis of normal face perception. The present study of a new case of acquired prosopagnosia with bilateral occipito-temporal lesions but a structurally intact FFA and OFA investigated whether the lesion overlapped with the face network and whether the structurally intact FFA showed a face selective response. We also investigated the behavioral correlates of the neural findings and assessed configural processing in the context of facial and non-facial identity recognition, expression recognition and memory, also focusing on the face-selectivity of each specific deficit. The findings reveal a face-selective response in the FFA, despite lesions in the face perception network. At the behavioural level, the results showed impaired configural processing for facial identity, but not for other stimulus categories and not for facial expression recognition. These findings challenge a critical role of the FFA for face identity processing and support a domain-specific account of configural processing.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Being the victim of virtual abuse changes default mode network responses to emotional expressions

Recent behavioural studies have provided evidence that virtual reality (VR) experiences have an impact on socio-affective processes, and a number of findings now underscore the potential of VR for therapeutic interventions. An interesting recent result is that when male offenders experience a violent situation as a female victim of domestic violence in VR, their sensitivity for recognition of fearful facial expressions improves. A timely question now concerns the underlying brain mechanisms of these behavioural effects as these are still largely unknown. The current study used fMRI to measure the impact of a VR intervention in which participants experienced a violent aggression from the specific vantage point of the victim. We compared brain processes related to facial and bodily emotion perception before and after the VR experience. Our results show that the virtual abuse experience led to an enhancement of Default Mode Network (DMN) activity, specifically associated with changes in the processing of ambiguous emotional stimuli. In contrast, DMN activity was decreased when observing fully fearful expressions. Finally, we observed increased variability in brain activity for male versus female facial expressions. Taken together, these results suggest that the first-person perspective of a virtual violent situation impacts emotion recognition through modifications in DMN activity. Our study contributes to a better understanding of the brain mechanisms associated with the behavioural effects of VR interventions in the context of a violent confrontation with the male participant embodied as a female victim. Furthermore, this research also consolidates the use of VR embodied perspective-taking interventions for addressing socio-affective impairments.

Laser picoscopy of valence electrons in solids

Valence electrons contribute a small fraction of the total electron density of materials, but they determine their essential chemical, electronic and optical properties. Strong laser fields can probe electrons in valence orbitals^1-3 and their dynamics^4-6 in the gas phase. Previous laser studies of solids have associated high-harmonic emission^7-12 with the spatial arrangement of atoms in the crystal lattice^13,14 and have used terahertz fields to probe interatomic potential forces¹⁵. Yet the direct, picometre-scale imaging of valence electrons in solids has remained challenging. Here we show that intense optical fields interacting with crystalline solids could enable the imaging of valence electrons at the picometre scale. An intense laser field with a strength that is comparable to the fields keeping the valence electrons bound in crystals can induce quasi-free electron motion. The harmonics of the laser field emerging from the nonlinear scattering of the valence electrons by the crystal potential contain the critical information that enables picometre-scale, real-space mapping of the valence electron structure. We used high harmonics to reconstruct images of the valence potential and electron density in crystalline magnesium fluoride and calcium fluoride with a spatial resolution of about 26 picometres. Picometre-scale imaging of valence electrons could enable direct probing of the chemical, electronic, optical and topological properties of materials.

Reorganization of Sound Location Processing in the Auditory Cortex of Blind Humans

Auditory spatial tasks induce functional activation in the occipital-visual-cortex of early blind humans. Less is known about the effects of blindness on auditory spatial processing in the temporal-auditory-cortex. Here, we investigated spatial (azimuth) processing in congenitally and early blind humans with a phase-encoding functional magnetic resonance imaging (fMRI) paradigm. Our results show that functional activation in response to sounds in general-independent of sound location-was stronger in the occipital cortex but reduced in the medial temporal cortex of blind participants in comparison with sighted participants. Additionally, activation patterns for binaural spatial processing were different for sighted and blind participants in planum temporale. Finally, fMRI responses in the auditory cortex of blind individuals carried less information on sound azimuth position than those in sighted individuals, as assessed with a 2-channel, opponent coding model for the cortical representation of sound azimuth. These results indicate that early visual deprivation results in reorganization of binaural spatial processing in the auditory cortex and that blind individuals may rely on alternative mechanisms for processing azimuth position.

Looking at the face and seeing the whole body. Neural basis of combined face and body expressions

In the natural world, faces are not isolated objects but are rather encountered in the context of the whole body. Previous work has studied the perception of combined faces and bodies using behavioural and electrophysiological measurements, but the neural correlates of emotional face–body perception still remain unexplored. Here, we combined happy and fearful faces and bodies to investigate the influence of body expressions on the neural processing of the face, the effect of emotional ambiguity between the two and the role of the amygdala in this process. Our functional magnetic resonance imaging analyses showed that the activity in motor, prefrontal and visual areas increases when facial expressions are presented together with bodies rather than in isolation, consistent with the notion that seeing body expressions triggers both emotional and action-related processes. In contrast, psychophysiological interaction analyses revealed that amygdala modulatory activity increases after the presentation of isolated faces when compared to combined faces and bodies. Furthermore, a facial expression combined with a congruent body enhanced both cortical activity and amygdala functional connectivity when compared to an incongruent face–body compound. Finally, the results showed that emotional body postures influence the processing of facial expressions, especially when the emotion conveyed by the body implies danger.

The Influence of Conscious and Unconscious Body Threat Expressions on Motor Evoked Potentials Studied With Continuous Flash Suppression

The observation of threatening expression in others is a strong cue for triggering an action response. One method of capturing such action responses is by measuring the amplitude of motor evoked potentials (MEPs) elicited with single pulse TMS over the primary motor cortex. Indeed, it has been shown that viewing whole body expressions of threat modulate the size of MEP amplitude. Furthermore, emotional cues have been shown to act on certain brain areas even outside of conscious awareness. In the current study, we explored if the influence of viewing whole body expressions of threat extends to stimuli that are presented outside of conscious awareness in healthy participants. To accomplish this, we combined the measurement of MEPs with a continuous flash suppression task. In experiment 1, participants were presented with images of neutral bodies, fearful bodies, or objects that were either perceived consciously or unconsciously, while single pulses of TMS were applied at different times after stimulus onset (200, 500, or 700 ms). In experiment 2 stimuli consisted of neutral bodies, angry bodies or objects, and pulses were applied at either 200 or 400 ms post stimulus onset. In experiment 1, there was a general effect of the time of stimulation, but no condition specific effects were evident. In experiment 2 there were no significant main effects, nor any significant interactions. Future studies need to look into earlier effects of MEP modulation by emotion body stimuli, specifically when presented outside of conscious awareness, as well as an exploration of other outcome measures such as intracortical facilitation.

Influence of continuous flash suppression mask frequency on stimulus visibility

The continuous flash suppression (CFS) paradigm is increasingly used in consciousness research, but its mechanisms are still not fully understood. To better understand its temporal properties, we presented the CFS masks at 9 frequencies, and examined their influence on stimuli visibility, while taking into account the inter-individual variability and the change of CFS suppression as the experiment progressed. The frequencies consisted of fundamental frequencies of 3, 4 and 5 Hz, and their 2nd and 3rd harmonics, which included the 10 Hz frequency typically used in most of the CFS studies. We found that the suppression of stimulus awareness was stronger under 4, 6 and 8 Hz than 10 Hz. After controlling for inter-individual variability with mixed-effects analysis, we found that the number of seen trials was lower for the 4 Hz-basis frequencies than the 5 Hz ones, and was lower for the 2nd than 3rd harmonic. We propose that this may be caused by an interaction between the CFS masks and the ongoing sampling of the attentional mechanism. Examining individual data, we also found a habituation effect that the participants saw significantly more stimuli as the experiment progressed. Our results suggest that these factors need to be taken care of in future CFS studies in order to achieve optimal visual awareness suppression and ensure the generalizability of results.

Cost-effectiveness analysis of the addition of bevacizumab to chemotherapy as induction and maintenance therapy for metastatic non-squamous non-small-cell lung cancer

BACKGROUND

The BEYOND trial found that the addition of bevacizumab (B) to paclitaxel-carboplatin (PC) chemotherapy provided a significant clinical benefit to Chinese patients with metastatic non-squamous non-small-cell lung cancer (NSCLC). This study aimed to evaluate the cost-effectiveness of adding B to first-line PC induction and continuation maintenance therapy from a Chinese perspective.

METHODS

A Markov model was developed to estimate the cost and effectiveness of B + PC in the induction and maintenance therapy of patients with metastatic non-squamous NSCLC. Costs were calculated in the Chinese setting, and health outcomes derived from the BEYOND trial were measured as quality-adjusted life years (QALYs). A one-way sensitivity analysis was conducted to explore the impact of various parameters in the study.

RESULTS

The B + PC treatment was more costly ($112,943.40 versus $32,171.43) and more effective (1.07 QALYs versus 0.80 QALYs) compared with the PC treatment. Adding B to the PC regimen for non-squamous NSCLC results in an incremental cost-effectiveness ratio of $299,155.44 per QALY, which exceeded the accepted societal willingness-to-pay threshold ($23,970.00) for China. In the sensitivity analysis, the duration of progression-free survival (PFS) for the B + PC group, the cost of the PFS state for B + PC group and the price of B were considered the most sensitive factors in the model.

CONCLUSIONS

The addition of B to first-line PC induction and maintenance therapy was not determined to be a cost-effective strategy for metastatic non-squamous NSCLC in China, even when an assistance program was provided.

Looming sensitive cortical regions without V1 input: evidence from a patient with bilateral cortical blindness

Fast and automatic behavioral responses are required to avoid collision with an approaching stimulus. Accordingly, looming stimuli have been found to be highly salient and efficient attractors of attention due to the implication of potential collision and potential threat. Here, we address the question of whether looming motion is processed in the absence of any functional primary visual cortex and consequently without awareness. For this, we investigated a patient (TN) suffering from complete, bilateral damage to his primary visual cortex. Using an fMRI paradigm, we measured TN's brain activation during the presentation of looming, receding, rotating, and static point lights, of which he was unaware. When contrasted with other conditions, looming was found to produce bilateral activation of the middle temporal areas, as well as the superior temporal sulcus and inferior parietal lobe (IPL). The latter are generally thought to be involved in multisensory processing of motion in extrapersonal space, as well as attentional capture and saliency. No activity was found close to the lesioned V1 area. This demonstrates that looming motion is processed in the absence of awareness through direct subcortical projections to areas involved in multisensory processing of motion and saliency that bypass V1.

The Body as a Tool for Anger Awareness--Differential Effects of Angry Facial and Bodily Expressions on Suppression from Awareness

Emotional signals are perceived whether or not we are aware of it. The evidence so far mostly came from studies with facial expressions. Here, we investigated whether the pattern of non-conscious face expression perception is found for whole body expressions. Continuous flash suppression (CFS) was used to measure the time for neutral, fearful, and angry facial or bodily expressions to break from suppression. We observed different suppression time patterns for emotions depending on whether the stimuli were faces or bodies. The suppression time for anger was shortest for bodily expressions, but longest for the facial expressions. This pattern indicates different processing and detection mechanisms for faces and bodies outside awareness, and suggests that awareness mechanisms associated with dorsal structures might play a role in becoming conscious of angry bodily expressions.

Predictors of early treatment discontinuation in a cohort of patients treated with boceprevir-based therapy for hepatitis C infection

In this real-world cohort, 49% of patients stopped boceprevir-based hepatitis C therapy early, with only 20% stopping due to treatment futility. Having more comorbidities was significantly associated with early discontinuation. Tolerability of boceprevir-based regimens may be substantially worse than reported in clinical trials, particularly for patients with comorbidities.

Neural correlates of body and face perception following bilateral destruction of the primary visual cortices

Non-conscious visual processing of different object categories was investigated in a rare patient with bilateral destruction of the visual cortex (V1) and clinical blindness over the entire visual field. Images of biological and non-biological object categories were presented consisting of human bodies, faces, butterflies, cars, and scrambles. Behaviorally, only the body shape induced higher perceptual sensitivity, as revealed by signal detection analysis. Passive exposure to bodies and faces activated amygdala and superior temporal sulcus. In addition, bodies also activated the extrastriate body area, insula, orbitofrontal cortex (OFC) and cerebellum. The results show that following bilateral damage to the primary visual cortex and ensuing complete cortical blindness, the human visual system is able to process categorical properties of human body shapes. This residual vision may be based on V1-independent input to body-selective areas along the ventral stream, in concert with areas involved in the representation of bodily states, like insula, OFC, and cerebellum.

Abstract P4-02-08: Quantitative Characterization of 3D Vasculature Spatial Patterns Within Tumor Microenvironment of Breast Cancer Stem Cells

The sustainment characters of cancer stem cells (CSCs) such as self-renew and differentiation to other tumor cells greatly depend on the tumor microenvironment, which is composed of many components, e.g. vasculature, extracellular matrix, epithelial cells, stromal cells, as well as nutrients and oxygen. As vasculature is an important factor for the CSC and tumor development, the understanding of their spatial patterns is essential for calibrating the CSC-microenvironment interactions in mathematical modeling. In this study, we acquired the vasculature in side tumors and normal breast tissues by using two-photon fluorescence microscopy, which enables 3D in vivo imaging. We developed an advanced vasculature segmentation approach for an objective and accurate quantification of the vasculature in 3D image volumes. The approach integrates supervoxel analysis and the orientation guided hidden Markov random field (ori-HMRF) modeling together to compensate for low quality images, e.g., low signal-to-noise ratio (SNR) and uneven background. By constructing a new feature space that combines the CIELAB color space and the coordinates space, the supervoxel analysis divides an image volume into subregions with local similar intensity and restricted regular shape, boundaries of which can delineate the vasculature boundaries accurately even in low intensity contrast regions. We further designed a set of features for the separation of blood vessel regions from the background. To make use of the context information, i.e. the continuity of vasculature, the ori-HMRF model is used to incorporate the consistency of vasculatures' orientation in order to reduce the false positives and negatives. Experimental results on image volumes from both breast cancer and normal breast tissues show that the proposed method can effectively reconstruct the vasculature structure with the CSC embedded tumor microenvironment.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-02-08.

Abstract P3-06-14: Identification of Prognosis-Relevant Subgroups in Patients with Chemoresistant Triple Negative Breast Cancer

Purpose: Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. TNBC patients with pathologic complete response (pCR) have excellent survival, but those with residual disease after neoadjuvant chemotherapy have significantly worse outcome. However, some patients having extensive residual cancer burden after neoadjuvant chemotherapy do not relapse, and we hypothesize that there may be subgroups with diverse prognosis among these chemoresistant TNBC patients.

Methods: Forty-nine cases with residual cancer from 111 TNBC patients treated with neoadjuvant chemotherapy (in M.D. Anderson Cancer Center, 2000–2006) constituted the discovery cohort. Twenty-five chemoresistant samples from 47 neoadjuvant chemotherapy-treated TNBC (in Baylor College of Medicine and Methodist Hospital, 2002–2006) were chosen for validation. Extended validation was performed in 269 operable TNBC predicted to be chemoresistant (using a JAMA-published genomic predictor) from public databases.

Results: By comparing the gene expression data from cases in relapse with those from un-relapsed cases, we established a 7-gene prognostic signature (including AR, ESR2, GATA3, GBX2, KRT16, MMP28, and WNT11) using dChip and gene enrichment analyses. In the discovery cohort, the signature showed positive predictive value (PPV; i.e., cumulative relapse rate of patients predicted to relapse in 3 years) of 95.4% and negative predictive values (NPV; i.e., relapse-free survival of patients predicted not to relapse in 3 years) of 100%. In the validation cohort, the classifier predicted correctly with PPV of 75.0% and NPV of 76.9% at 3 years. Compared with patients predicted not to relapse, those predicted to relapse had a hazard ratio of 3.37 (95% CI, 1.15–9.85) for disease recurrence or death in 3 years. In an extended validation cohort of 269 patients, our signature discriminated chemoresistant TNBC in overall cohort (PPV, 52.4%; NPV, 77.7%; log rank P < 0.0001), or each subset (e.g., log rank p = 0.001 for Rotterdam set; p = 0.013 for Frankfurt set), with adjusted overall hazard ratio of 2.07 (95% CI, 1.26–3.39). This signature was the only marker that could effectively predict the relapse in patients with chemoresistant TNBC. Of note, the subgroup predicted not to relapse was characterized by high expression of luminal-like genes (AR, GATA3), while the subgroup predicted to have high possibility of relapse was characterized by high expression of cancer stem cell and epithelial-to-mesenchymal transition associated genes (WNT11, MMP28). The former corresponded to the luminal AR subtype and the latter to the mesenchymal stem-like subtype, according to Pietenpol's TNBC subtype classification.

Conclusion: We developed a clinically useful prognostic signature for chemoresistant TNBC. For these chemoresistant TNBC patients, new therapeutic strategies targeting AR-activation or cancer stem cells need to be developed.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-14.

GP88 Serum Level Is Increased in Breast Cancer Patients with Disease Progression

GP88 (progranulin) is an 88-kDa glycoprotein autocrine growth factor that plays a critical role in breast tumorigenesis. GP88 is expressed in human BC tumors in a positive correlation with their tumorigenicity. In estrogen receptor positive (ER+) cells, GP88 expression is low and is stimulated by estradiol whereas in ER negative (ER-) cells, it is constitutively overexpressed. In ER+ cells, increased GP88 expression was found to be associated with resistance to anti-estrogen therapy. In Her-2 overexpressing breast tumors, increased GP88 expression was associated with Herceptin resistance. Inhibition of GP88 expression in human breast adenocarcinoma cells resulted in a drastic reduction of tumor incidence and tumor growth in nude mice. Immunohistochemical studies carried out with 206 paraffin-embedded human breast biopsies have shown that GP88 is expressed in invasive ductal carcinomas in correlation with expression of markers of poor prognosis whereas normal tissues and benign breast lesions were negative. Importantly, high GP88 expression in tissue biopsies was accompanied by decreased disease-free and overall survival. Since GP88 contains a signal peptide for secretion, we have shown that GP88 can be found in serum. An IRB approve blood sampling study of 189 patients (Race: Caucasian- 91, African American-92, Asian-6; median age- 51 with a range from 26 to 81) established at the University of Maryland demonstrated that GP88 was measurable in serum and that GP88 serum level was statistically elevated in breast cancer patients when compared to healthy individuals. Median level of GP88 was 40.7 ng/ml (range 6.4-80) in early stage (stage 1 –3) BC pts (p- value = 0.007) and 45.3 ng/ml (range 9.8 to 158.4) in stage 4 metastatic BC patients (p-value= 0.0007). Statistically significant increase in circulating GP88 level was found in early stages as well as in metastatic disease when compared to healthy individuals.Since we have shown that GP88 tissue expression was associated with increased disease recurrence, the present study was focused on examining whether GP88 serum level was also increased in disease progression and could be used to monitor disease recurrence. Our data show that patients with disease recurrence or progression presented a 5 to 10 fold increase in their GP88 serum levels.This study identifies GP88 as a measurable biomarker for recurrence or disease progression not only at the tissue but also at the serum level.This study is supported by grants from MIPS, the Avon Foundation and from the National Cancer Institute.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6040.

A Culturally-Specific Dietary Plan To Manage Weight Gain among African American Breast Cancer Survivors: A Feasibility Study

Background. African American (AA) women are less likely to survive for five years after a breast cancer diagnosis than Caucasian women. The higher prevalence of obesity in AA women may contribute to this disparity. Weight gain following breast cancer treatment is one of the few modifiable risk factors for breast cancer recurrence and mortality. AA breast cancer survivors face unique cultural and economic barriers to adopting diets which reduce the likelihood of weight gain.Objective. To determine the feasibility of adopting and maintaining a culturally-specific low-fat eating plan in a population of low to middle income AA breast cancer survivors.Participants. AA women recruited through urban medical centers who were between 30 to 75 years old, had a confirmed diagnosis of stage 0, I, II, III, or IIIA primary breast cancer, and had incomes < $50,000 per year.Methods. A culturally-specific dietary intervention was developed, based on the Women's Intervention Nutrition Study (WINS), to reduce consumption of dietary fat to 25% of total calories, while increasing fruits and vegetables.Eligible participants were enrolled in a one-year feasibility study. Participants received the Culturally-Specific WINS Low-Fat Eating Plan (WLEP) and 8 individual nutritional counseling sessions with a trained diet technician, to help reduce and maintain their fat intake to 25% of total calories. The intervention also included bi-monthly educational group meetings and follow-up telephone contacts with diet technicians.Study Measures. Dietary patterns were assessed with 3-day food records at baseline and follow-up. Compliance with the Culturally-Specific WLEP was defined as 1) dietary fat intake ≤ 25% of total calories; and 2) at least 6 to 7 servings of fruits and vegetables per day. Psychosocial factors and dietary biomarkers were also measured at baseline and follow-up to examine their association with study outcomes. Psychosocial factors included perceived susceptibility to recurrence, quality of life, and social support. Dietary biomarkers included weight, height, waist-hip circumference, blood pressure, lipids, serum fatty acid concentrations, insulin and insulin-like growth factors, glucose, and levels of sex hormone-binding globulins.Results. A total of 9 AA breast cancer survivors are enrolled and receiving the intervention. Baseline and six-month follow-up results for the psychosocial factors and dietary biomarkers associated with dietary compliance and weight maintenance will be reported in October 2009.Conclusions. A population of low to middle income AA breast cancer survivors with limited education and resources demonstrated compliance with the Culturally-Specific WLEP, thereby reducing their risk of cancer recurrence through diet. Procedures and data from this feasibility study will be used in a multi-center clinical trial of the Culturally-Specific WLEP.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1053.

Association of serum levels of the growth factor GP88 with disease progression in breast cancer patients

e22021

Background: The autocrine growth factor GP88 is an important player in breast cancer. GP88 is expressed in human BC tumors in correlation with their tumorigenicity. Increased GP88 expression was associated with anti-estrogen therapy resistance in ER+ cells and Herceptin resistance in Her-2 overexpressing breast tumors. Inhibition of GP88 expression inhibited tumor incidence and growth in nude mice. Immunohistochemical studies have shown that GP88 is expressed in invasive ductal carcinomas (IDC) and that high GP88 expression correlated with increased recurrence and mortality. Since GP88 is found in serum, we hypothesized that GP88 was elevated in the sera of breast cancer patients compared to healthy individuals and that GP88 serum level increases with disease progression. Methods: An IRB approved prospective study was established at the University of Maryland Breast Clinic to determine the serum level of GP88 in breast cancer patients (BC pts). Approximately 5 ml of blood was drawn every three months. GP88 serum concentration was determined in triplicate by human GP88 enzyme immunoassay. 190 BC pts were accrued. Sera from healthy volunteers (HV) were obtained to establish GP88 baseline. BC patient characteristics: Caucasian- 91, African American-92, Asian-6; median age, 51 (range 29- 86), stage I - 48, II - 52, III - 26, IV - 63. Results: Median serum GP88 level was 28.7 ng/ml (range 16.6–38.2) in HV, 40.7 ng/ml (range 6.4–100) in early stage (stage 1 -3) BC pts (p- value = 0.007) and 45.3 ng/ml (range 9.8 to 158.4) in stage 4 BC patients (p- value= 0.0007). Statistically significant increase in serum GP88 level was found in early stages as well as in metastatic disease when compared to HV. In addition, patients that were initially diagnosed with early stage disease but recurred showed a 5 to 10 fold increase in their GP88 serum levels. Conclusions: GP88 serum level is significantly higher in the sera of BC than HV subjects. Moreover, GP88 serum level increased in association with disease recurrence and progression. This study identifies GP88 as a measurable biomarker for disease progression not only at the tissue but also at the serum level. These results are also interesting since GP88 is also a therapeutic target of malignant progression of breast carcinoma.

No significant financial relationships to disclose.

Elevated serum levels of the growth factor GP88 are found in breast cancer patients when compared to healthy individuals

Abstract #2006

Background: GP88 is an autocrine growth factor that plays a critical role in breast tumorigenesis. GP88 is expressed in human BC tumors in a positive correlation with their tumorigenicity. Increased GP88 expression is associated with resistance to anti-estrogen therapy in ER + cells and with herceptin resistance in Her-2 overexpressing breast tumors. Inhibition of GP88 expression in human breast adenocarcinoma inhibited tumor incidence and growth in nude mice. Immunohistochemical studies have shown that GP88 was expressed in invasive ductal carcinomas in correlation with the expression of poor prognosis markers whereas normal tissues and benign lesions were negative. High GP88 expression in tumor biopsies was accompanied by decreased disease-free survival. Since GP88 can be secreted, we have hypothesized that GP88 could be secreted in the circulation and found in serum. We examined whether GP88 could be found in the circulation and whether GP88 could be elevated in the sera of breast cancer patients when compared to healthy individuals.
 Methods: An IRB approved blood sampling study was conducted at the University of Maryland Breast Clinic to determine the serum level of GP88 in healthy volunteers (HV) and breast cancer patients (BC pts). Serum GP88 concentration was determined in triplicate by quantitative enzyme immunoassay. 189 BC pts were accrued. In addition, sera from 18 HV were obtained to establish a GP88 baseline in healthy volunteers. BC patient characteristics: Race: Caucasian- 91, African American-92, Asian-6; median age, 51 (range 29-86), stage I – 48, II - 52, III – 26, IV - 63.
 Results: Circulating GP88 was measurable in the serum. Median level of GP88 was 28.7 ng/ml (range 16.6-38.2) in HV; 40.7 ng/ml (range 6.4-100) in early stage (stage 1 –3) BC pts (p- value = 0.007) and 45.3 ng/ml (range 9.8 to 158.4) in stage 4 metastatic BC patients (p-value= 0.0007). Statistically significant increase in circulating GP88 level was found in early stages as well as in metastatic disease. Correlation studies with BC prognostic factors such as stage, tumor size, lymph node involvement, tumor grade and presence of ER and HER-2 will be presented.
 Conclusion: GP88 can be detected in the sera of HV and BC pts. Comparison between the two groups of subjects indicates that GP88 level is significantly higher in the sera of BC pts. These studies are important as they identify as a measurable circulating biomarker GP88 that is also a therapeutic target of malignant transformation or malignant progression of breast carcinoma (BC). Future studies will examine whether there is any correlation between the serum level of GP88 and therapeutic response to systemic therapy in breast cancer patients.
 This study was supported by grant from MIPS, the Avon Foundation and 1R43 CA 124179-01A1 from the National Institutes of Health.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2006.

Serum protein signatures detect early radiographic osteoarthritis

OBJECTIVE

To test the hypothesis that early knee and hand osteoarthritis (OA) development is characterized by detectable changes in serum proteins relevant to inflammation, cell growth, activation, and metabolism several years before OA becomes radiographically evident.

METHODS

Using microarray platforms that simultaneously test 169 proteins relevant to inflammation, cell growth, activation and metabolism, we conducted a case-control study nested within the Baltimore Longitudinal Study of Aging (BLSA). Subjects included 22 incident cases of OA and 66 age-, sex- and body mass index (BMI)-matched controls. Serum samples tested were obtained at the time of radiographic classification as either case or control, and up to 10 years earlier at a time when all participants were free of radiographic OA. Proteins with mean signal intensities fourfold higher than background were compared between cases and controls using multivariate techniques.

RESULTS

Sixteen proteins were different between OA cases compared to controls. Four of these proteins [matrix metalloproteinase (MMP)-7, interleukin (IL)-15, plasminogen activator inhibitor (PAI)-1 and soluble vascular adhesion protein (sVAP)-1] were already different in samples obtained 10 years before radiographic classification and remained different at the time of diagnosis. Six additional proteins were only associated with subsequent OA development and not with established OA.

CONCLUSIONS

Changes in serum proteins implicated in matrix degradation, cell activation, inflammation and bone collagen degradation products accompany early OA development and can precede radiographic detection by several years.

Clinical significance of pleural lavage cytology in non-small cell lung cancer: A meta-analysis

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Background: The clinical significance of pleural lavage cytology (PLC) in non-small-cell lung cancer (NSCLC) remains controversial. This study was performed to estimate the associations of positive PLC with the main clinicopathological characteristics, and its prognostic value. Methods: PLC studies were identified on Medline, supplemented by manual search of bibliographies and proceedings. Authors were contacted for updated information. The quality of the studies was evaluated, and the data were extracted. Pooled odds ratios (ORs) and pooled hazard ratios (HRs) with confidence intervals [95% CIs] were calculated to evaluate the association of positive PLC with clinico-pathological characteristics and survival respectively. Results: Nineteen articles assessing PLC in NSCLC were selected for this study after exclusion of repeated publications or reports with little clinical detail. Positive PLC was diagnosed in 10.2% (516) of a total of 5073 patients. Positive PLC was strongly associated with lymphatic permeation (OR 4.96 [3.29, 7.54]), pleural invasion (OR 4.38 [2.16, 8.89], and vascular involvement (OR 2.94 [1.99, 4.35]). It was also found to be associated with advanced T stage, N stage, and TNM stage. Positive PLC was more frequent in adenocarcinoma than in squamous cell carcinoma (OR 2.32, [1.51, 3.52]). It was relatively more common in moderately- and poorly-differentiated tumors than in well-differentiated tumors (OR 1.89 [0.86, 4.16]). No association was found between positive PLC and fine needle aspiration cytology (OR 1.04 [0.58, 1.81]). Positive PLC was associated with high overall recurrence (OR 2.51 [1.79, 3.53]), as well as high local recurrence (OR 3.85 [1.57, 9.44]) and distant recurrence (2.58 [1.76, 3.76]). In analysis of survival, the overall HR for mortality was 2.43 [1.87, 3.16], suggesting significantly poorer survival for patients with positive PLC. Conclusions: Positive PLC in NSCLC is strongly associated with several existing poor prognosticators including pleural invasion, lymphatic spread, and vascular involvement. It may indicate locally advanced disease with high risk of recurrence and poor survival. We recommend that the PLC test be included in future clinical trials of adjuvant therapy for patients with NSCLC.

No significant financial relationships to disclose.

Transcriptional profiling suggests that Barrett's metaplasia is an early intermediate stage in esophageal adenocarcinogenesis

To investigate the relationship between Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC), we determined gene expression profiles of discrete pathological stages of esophageal neoplasia using a sequence-verified human cDNA microarray. Fifty one RNAs, comprising 24 normal esophagi (NE), 18 BEs, and nine EACs were hybridized to cDNA microarrays. Five statistical analyses were used for the data analysis. Genes showing significantly different expression levels among the three sample groups were identified. Genes were grouped into functional categories based on the Gene Ontology Consortium. Surprisingly, the expression pattern of BE was significantly more similar to EAC than to NE, notwithstanding the known histopathologic differences between BE and EAC. The pattern of NE was clearly distinct from that of EAC. Thirty-six genes were the most differentially modulated, according to these microarray data, in BE-associated neoplastic progression. Twelve genes were significantly differentially expressed in cancer-associated BE's plus EAC (as a single combined tissue group) vs noncancer-associated BE's. These genes represent potential biomarkers to diagnose EAC at its early stages. Our results demonstrate that molecular events at the transcriptional level in BE are remarkably similar to BE's-associated adenocarcinoma of the esophagus. This finding alarmingly implies that BE is biologically closer to cancer than to normal esophagus, and that the cancer risk of BE is perhaps higher than we had imagined. These findings suggest that changes modulated at the molecular biologic level supervene earlier than histologic changes, and that BE is an early intermediate stage in the process of EAC.

Interferon-beta-1a induces increases in vascular cell adhesion molecule: implications for its mode of action in multiple sclerosis

We investigated soluble vascular cell adhesion molecule-1 (sVCAM) levels and MRI lesions over 24 weeks in 15 Relapsing Remitting MS (RRMS) patients randomized prospectively to receive once-weekly (qw) IFN-beta-1a 30 mug intramuscularly (IM) (Group I, 8 patients) or three-times-weekly (tiw) IFN-beta-1a 44 mug subcutaneously (SC) (Group II, 7 patients). Both groups demonstrated a significant increase in sVCAM during treatment when compared to pre-treatment levels. Patients on IFN-beta-1a 44 mug SC tiw had a significant (p<0.0001) mean increase in sVCAM of 321.9 ng/ml which was significantly greater (p<0.0001) than with IFN-beta-1a 30 mug IM qw (68.6 ng/ml). There was a negative correlation between combined unique (CU) MRI lesions and sVCAM levels within the IFN-beta-1a 44 mug SC tiw group (slope=-0.00106, p=0.009). We postulate that the mode of action of IFN-beta therapy in MS may involve the induction of an increase in sVCAM. sVCAM could bind VLA-4 on T-cells and intercept their adhesion to the blood brain barrier (BBB). This mechanism is consistent with the observed clinical effect of IFN-beta in reducing MRI contrast enhancing lesions.

Epidemiology of capsular and surface polysaccharide in Staphylococcus aureus infections complicated by bacteraemia

Staphylococcus aureus is a leading cause of serious hospital- and community-acquired infections. The discovery of serologically distinct capsular polysaccharides on the surface of clinical isolates has allowed the development of vaccines and passive protective immunity. We have studied patient characteristics, infection characteristics and the surface and capsular polysaccharide serotype distribution in patients with S. aureus infections complicated by bacteraemia admitted to VA hospitals in Maryland between 1995 and 2000. Nine hundred and ninety-three blood cultures from 331 patients were positive for S. aureus. Thirty-eight percent of patients had diabetes, 11% had end-stage renal failure, and 23% were injection drug users. Forty-two percent of infections were caused by methicillin-resistant strains (MRSA), and 60% were acquired during hospitalization. Serotyping of the first available isolate per patient (N=234 isolates) using polyclonal antibodies showed three major phenotypes--42%, type 8 (T8) capsule; 50%, type 5 (T5) capsule; and 8%, 336 polysaccharide. MRSA isolates were significantly more likely to be T5 than methicillin-susceptible isolates (66% vs. 39%, P<0.001). The proportion of T5 MRSA increased significantly (years 1-2: 41%; years 3-4: 65%; years 5-6: 90%, P<0.001). This large sample of patients with serious S. aureus infection confirms that capsular polysaccharides T5 and T8 cause most human infections, and together with serotype 336, account for nearly all those with bacteraemia.

Phosphatidylinositide 3-kinase/AKT in radiation responses

Ionizing or ultraviolet radiation-induced cellular survival signaling pathways induce development of cancer and insensitivity of tumor cells to radiation therapy. Accumulating evidence suggests that the phosphatidylinositide 3-kinase (PI3K)/AKT signal pathway is a major contributor to radioresistance. In many cell types PI3K/AKT signaling is a key cytoprotective response downstream of the EGFR family receptors and mediated carcinogenesis. Cytokines, such as HGF, IGF-I, and IL-6 also protects cells against apoptosis induced by radiation through PI3K/AKT pathway. The mechanics by which PI3K/AKT signaling functions in radiation responses may include its regulation of mitochondrial proteins, transcription factors, translation machinery, and cell-cycle progression. In addition, cross-talk between the PI3K/AKT pathway and mitogen-activated protein kinases, protein kinase A, and protein kinase C signal pathway may also play an important role.

Signalling mechanisms of anoikis

Apoptosis following loss of cell anchorage ('anoikis') is of relevance for development, tissue homeostasis and disease. Integrins regulate cell viability through their interaction with the extracellular matrix and they can sense mechanical forces arising from the matrix and convert these stimuli to chemical signals capable of modulating intracellular signal transduction. Recently it has been shown that protein kinase signalling pathways and apoptosis-related molecular control anoikis both positively and negatively. Focal adhesion kinase, when activated by integrins, can suppress anoikis. Phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase may mediate the anoikis-suppressing effects of cells. Conversely, the stress-activated protein kinase/Jun amino-terminal kinase pathway promotes anoikis. In addition, certain bcl-2 and bcl-2-related proteins may also participate in the regulating of anoikis. In this review, molecular mechanisms of signal pathway inducing and perpetuating detachment-induced apoptosis will be discussed with special emphasis on the role of integrins, focal adhesion kinase, phosphatidylinositol 3-kinase/Akt, mitogen-activated protein kinase and bcl-2 family members.

Wild type p53 sensitizes soft tissue sarcoma cells to doxorubicin by down-regulating multidrug resistance-1 expression

BACKGROUND

p53 mutations occur in almost half of all soft tissue sarcomas (STS) and may contribute to multidrug resistance (MDR) in patients with STS. Doxorubicin (Dox) is one of the most active single agents in STS but is less effective in STS with p53 mutations. The effect of reintroducing wild type (wt) p53 into STS cells harboring p53 mutations on the cytotoxicity of DOX in vitro and in vivo was studied.

METHODS

The following cell lines were used in this study: SKLMS-1 STS cells, which do not express wt p53; two wt p53 stable transfectant cells derived from SKLMS-1 cells; and SKLMS-1 transfectant cells from a p53 temperature-sensitive mutant that expresses wt p53 at 32 degrees C and mutant p53 at 38 degrees C. The cytotoxicity of Dox was examined by [3-(4,5-dimethylthiazzol-2-yl)-2,5-diphenltetrazolium] (MTT) and clonogenetic assay, and the effect of reintroducing wt p53 on tumor suppression by Dox was evaluated with a tumorigenicity assay. DNA fragmentation was used to detect apoptosis. MDR-1 P-glycoprotein (P-gp) expression was detected by Western blot and immunohistochemical analyses of protein levels and by Northern blot analysis of mRNA levels, respectively. The intracellular accumulation of Dox was detected by flow cytometric analysis.

RESULTS

The 50% inhibitory concentration (IC(50)) of Dox for the SKLMS-1 wt p53 transfectants decreased 16-fold compared with SKLMS-1 parental cells expressing mutant p53. Colony formation of SKLMS-1 cells after Dox treatment also was inhibited by wt p53 reintroduction. The tumorigenicity of SKLMS-1 cells was inhibited by wt p53 reintroduction alone or by Dox treatment alone and was inhibited further when p53 introduction was combined with Dox treatment in severe combined immunodeficient mice. Although no difference in DNA fragmentation, Bax expression, or Bcl-2 expression was detected among wt p53 transfectants and parental SKLMS-1 cells after Dox treatment, MDR-1 P-gp expression was decreased in wt p53 transfectants compared with parental SKLMS-1 cells. Furthermore, higher intracellular accumulations of Dox were found in wt p53 transfectants than that in SKLMS-1 cells.

CONCLUSIONS

Reintroduction of wt p53 into STS cells harboring p53 mutations can enhance their chemosensitivity to Dox through the inhibition of MDR-1 P-gp expression. Thus, the combination of p53 gene therapy and chemotherapy may increase the therapeutic efficacy in the treatment of patients with STS.

Phase locking in on-off intermittency

Dynamical behavior of on-off intermittency around chaos synchronization-desynchronization bifurcation parameter line is investigated in coupled identical chaotic oscillators. Along this parameter line, we find that on-off intermittency can transit from phase-unlocking status to phase-locking one in the phase space of variable differences, which can be regarded as a codimension-two bifurcation, i.e., combinative bifurcations of desynchronization and phase locking. In the phase-locking case, the motions of all oscillators are chaotic and they show on-off intermittency with respect to the synchronous manifold, however, spatial phase order of variable differences is clearly established.

Wild type p53 sensitizes soft tissue sarcoma cells to doxorubicin by down-regulating multidrug resistance-1 expression

BACKGROUND

p53 mutations occur in almost half of all soft tissue sarcomas (STS) and may contribute to multidrug resistance (MDR) in patients with STS. Doxorubicin (Dox) is one of the most active single agents in STS but is less effective in STS with p53 mutations. The effect of reintroducing wild type (wt) p53 into STS cells harboring p53 mutations on the cytotoxicity of DOX in vitro and in vivo was studied.

METHODS

The following cell lines were used in this study: SKLMS-1 STS cells, which do not express wt p53; two wt p53 stable transfectant cells derived from SKLMS-1 cells; and SKLMS-1 transfectant cells from a p53 temperature-sensitive mutant that expresses wt p53 at 32 degrees C and mutant p53 at 38 degrees C. The cytotoxicity of Dox was examined by [3-(4,5-dimethylthiazzol-2-yl)-2,5-diphenltetrazolium] (MTT) and clonogenetic assay, and the effect of reintroducing wt p53 on tumor suppression by Dox was evaluated with a tumorigenicity assay. DNA fragmentation was used to detect apoptosis. MDR-1 P-glycoprotein (P-gp) expression was detected by Western blot and immunohistochemical analyses of protein levels and by Northern blot analysis of mRNA levels, respectively. The intracellular accumulation of Dox was detected by flow cytometric analysis.

RESULTS

The 50% inhibitory concentration (IC(50)) of Dox for the SKLMS-1 wt p53 transfectants decreased 16-fold compared with SKLMS-1 parental cells expressing mutant p53. Colony formation of SKLMS-1 cells after Dox treatment also was inhibited by wt p53 reintroduction. The tumorigenicity of SKLMS-1 cells was inhibited by wt p53 reintroduction alone or by Dox treatment alone and was inhibited further when p53 introduction was combined with Dox treatment in severe combined immunodeficient mice. Although no difference in DNA fragmentation, Bax expression, or Bcl-2 expression was detected among wt p53 transfectants and parental SKLMS-1 cells after Dox treatment, MDR-1 P-gp expression was decreased in wt p53 transfectants compared with parental SKLMS-1 cells. Furthermore, higher intracellular accumulations of Dox were found in wt p53 transfectants than that in SKLMS-1 cells.

CONCLUSIONS

Reintroduction of wt p53 into STS cells harboring p53 mutations can enhance their chemosensitivity to Dox through the inhibition of MDR-1 P-gp expression. Thus, the combination of p53 gene therapy and chemotherapy may increase the therapeutic efficacy in the treatment of patients with STS.

[Measurement of the absorption coefficient of barium using cavity ringdown spectroscopy]

An apparatus for cavity ringdown spectroscopy was constructed and used for atomic absorption measurement. The transition probability for 6s6p1P1<--6s6s1S0 transition of barium atoms was obtained in the self-made apparatus. The relation between atomic absorption coefficient and atomic oven temperature was also analysed.

Generalized splay state in coupled chaotic oscillators induced by weak mutual resonant interactions

Dynamic behavior of coupled chaotic oscillators is investigated. A transition from high-dimensional hyperchaos to a generalized periodic splay state is found for extremely weak coupling. Chaotic nature of a single oscillator and mutual resonant interactions are regarded to be responsible for this self-organized ordering. The functional phase distribution of the generalized splay state, which is essentially different from the equal-phase-separation distribution of the conventional splay states, can be well predicted by analyzing a single periodically forced oscillator.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

[Preliminary study on pathogenicity of hepatitis G virus]

OBJECTIVE

To study the clinical, enzymatic and liver pathological changes in patients with hepatitis G virus (HGV) infection.

METHODS

RT- nested PCR was applied to detect HGV RNA in 368 patients with hepatic diseases. The liver biopsy tissue from one liver cirrhosis patient with simple HGV infection was examined.

RESULTS

Simple HGV RNA positive were found in 7 cases of 71 acute hepatitis jaundice, in 22 cases of 155 chronic hepatitis and in 3 cases of 51 liver cirrhosis. The immunohistochemistry of the liver biopsy tissue from a liver cirrhosis patient showed HGV NS5 antigen positive. However, HGV infection might occur simply or in combination with hepatitis B or C virus or super infected.

CONCLUSIONS

HGV RNA could be detected in acute hepatitis jaundice, chronic hepatitis, hepatitis B or C carriers, liver cirrhosis and hepatocellular carcinoma. HGV is proved to be a hepatotropic virus by pathological examination and immunohistochemistry, the virus located in the cytoplasm of the liver cells. It may cause chronic hepatitis and even liver cirrhosis, so HGV is pathogenic to liver tissue.