Therapeutic ultrasound to noninvasively create intracardiac communications in an intact animal model

OBJECTIVE

To determine if pulsed cavitational ultrasound therapy (histotripsy) can accurately and safely generate ventricular septal defects (VSDs) through the intact chest of a neonatal animal, with the eventual goal of developing a noninvasive technique of creating intra-cardiac communications in patients with congenital heart disease.

BACKGROUND

Histotripsy is an innovative ultrasonic technique that generates demarcated, mechanical tissue fractionation utilizing high intensity ultrasound pulses. Previous work has shown that histotripsy can create atrial septal defects in a beating heart in an open-chest canine model.

METHODS

Nine neonatal pigs were treated with transcutaneous histotripsy targeting the ventricular septum. Ultrasound pulses of 5-μsec duration at a peak negative pressure of 13 MPa and a pulse repetition frequency of 1 kHz were generated by a 1 MHz focused transducer. The procedure was guided by real-time ultrasound imaging.

RESULTS

VSDs were created in all pigs with diameters ranging from 2 to 6.5 mm. Six pigs were euthanized within 2 hrs of treatment, while three were recovered and maintained for 2-3 days to evaluate lesion maturation and clinical side effects. There were only transient clinical effects and pathology revealed mild collateral damage around the VSD with no significant damage to other cardiac or extra-cardiac structures.

CONCLUSIONS

Histotripsy can accurately and safely generate VSDs through the intact chest in a neonatal animal model. These results suggest that with further advances, histotripsy can be a useful, noninvasive technique to create intracardiac communications, which currently require invasive catheter-based or surgical procedures, to clinically stabilize newborn infants with complex congenital heart disease.

When it's time for a change: failures to track context in schizophrenia

INTRODUCTION

Reduction of P300 event-related potential amplitude in schizophrenia is perhaps the most replicated biological reflection of the illness. P300 is typically elicited by infrequent deviant events that are imbedded in a series of identical frequent standard events. Deviants have features that explicitly distinguish them from standards, whereas standards can be distinguished from each other based on their local sequential probabilities within the stimulus series. The improbable occurrence of a standard should generate a P300, but only if the implicit local context generated by the recent stimulus history is processed.

METHOD

To assess the ability of schizophrenia patients to process this implicit contextual information, ERPs were elicited from 22 controls and 16 schizophrenia patients during an auditory oddball task containing infrequent target tones (15%) and novel distracter sounds (15%) imbedded pseudo-randomly in a series of standard tones (70%). Consecutively presented standards following deviant stimuli varied in sequential probability from p=1.0 for the 1st standard to p=0.16 for the 4th consecutive standard.

RESULTS

Patients compared to controls demonstrated smaller P300 (P3a) to the fourth consecutive standard. However, in controls but not patients a contingent negative variation (CNV) was observed prior to the fourth standard, and an N2b/mismatch negativity (MMN) was observed following it.

CONCLUSIONS

These outcomes suggest that patients are deficient in using the implicit context established by recent stimulus history to anticipate that an otherwise standard stimulus was unlikely and its occurrence unexpected.

Neurophysiological Distinction between Schizophrenia and Schizoaffective Disorder

Schizoaffective disorder (SA) is distinguished from schizophrenia (SZ) based on the presence of prominent mood symptoms over the illness course. Despite this clinical distinction, SA and SZ patients are often combined in research studies, in part because data supporting a distinct pathophysiological boundary between the disorders are lacking. Indeed, few studies have addressed whether neurobiological abnormalities associated with SZ, such as the widely replicated reduction and delay of the P300 event-related potential (ERP), are also present in SA. Scalp EEG was acquired from patients with DSM-IV SA (n = 15) or SZ (n = 22), as well as healthy controls (HC; n = 22) to assess the P300 elicited by infrequent target (15%) and task-irrelevant distractor (15%) stimuli in separate auditory and visual "oddball" tasks. P300 amplitude was reduced and delayed in SZ, relative to HC, consistent with prior studies. These SZ abnormalities did not interact with stimulus type (target vs. task-irrelevant distractor) or modality (auditory vs. visual). Across sensory modality and stimulus type, SA patients exhibited normal P300 amplitudes (significantly larger than SZ patients and indistinguishable from HC). However, P300 latency and reaction time were both equivalently delayed in SZ and SA patients, relative to HC. P300 differences between SA and SZ patients could not be accounted for by variation in symptom severity, socio-economic status, education, or illness duration. Although both groups show similar deficits in processing speed, SA patients do not exhibit the P300 amplitude deficits evident in SZ, consistent with an underlying pathophysiological boundary between these disorders.

Qualitative effects of fresh and dried plum ingredients on vacuum-packaged, sliced hams

Boneless ham muscles (Semimembranosus+Adductor) were injected (20% w/w) with a curing brine containing no plum ingredient (control), fresh plum juice concentrate (FP), dried plum juice concentrate (DP), or spray dried plum powder (PP) at 2.5% or 5%. Hams were cooked, vacuum-packaged, stored at<4°C and evaluated at 2-week intervals over 10 week. Evaluations were performed on sliced product to determine cook loss, vacuum-package purge, Allo-Kramer shear force, 2-thiobarbituric acid-reactive substances (TBARS), proximate analysis, objective color, sensory panel color and sensory attributes. FP, DP and 2.5% PP increased (P<0.05) cook loss by 2% to 7% depending on treatment and level, but the highest cook loss (17.7%) was observed in hams with 5% PP. Shear force values increased as the level of plum ingredient increased (P<0.05) from 2.5% to 5%, and the highest shear values were observed in hams containing 5% FP. There were no differences (P>0.05) in lipid oxidation among treatments as determined by TBARS and sensory evaluation. FP and PP ham color was similar to the control, but DP had a more intense atypical color of cured ham. Minimal changes in physical, chemical and sensory properties were observed during storage of all treatments.

Temporal changes in C and N stocks of restored prairie: implications for C sequestration strategies

The recovery of ecosystem C and N dynamics after disturbance can be a slow process. Chronosequence approaches offer unique opportunities to use space-for-time substitution to quantify the recovery of ecosystem C and N stocks and estimate the potential of restoration practices for C sequestration. We studied the distribution of C and N stocks in two chronosequences that included long-term cultivated lands, 3- to 26-year-old prairie restorations, and remnant prairie on two related soil series. Results from the two chronosequences did not vary significantly and were combined. Based on modeling predictions, the recovery rates of different ecosystem components varied greatly. Overall, C stocks recovered faster than N stocks, but both C and N stocks recovered more rapidly for aboveground vegetation than for any other ecosystem component. Aboveground C and N reached 95% of remnant levels in only 13 years and 21 years, respectively, after planting to native vegetation. Belowground plant C and N recovered several decades later, while microbial biomass C, soil organic C (SOC), and total soil N recovered on a century timescale. In the cultivated fields, SOC concentrations were depleted within the surface 25 cm, coinciding with the depth of plowing, but cultivation apparently led to redistribution of soil C, increasing SOC stocks deeper in the soil profile. The restoration of prairie vegetation was effective at rebuilding soil organic matter (SOM) in the surface soil. Accrual rates were maintained at 43 g C x m(-2) x yr(-1) and 3 g N x m(-2) x yr(-1) in the surface 0.16 Mg/m2 soil mass during the first 26 years of restoration and were predicted to reach 50% of their storage potential (3500 g C/m2) in the first 100 years. We conclude that restoration of tallgrass prairie vegetation can restore SOM lost through cultivation and has the potential to sequester relatively large amounts of SOC over a sustained period of time. Whether restored prairies can retain the C apparently transferred to the subsoil by cultivation practices remains to be seen.

Isoform-specific effects of ApoE on HSV immediate early gene expression and establishment of latency

Alzheimer's disease (AD) is a common and devastating neurodegenerative disease in which most cases are of unknown, sporadic origin. In addition to age, the most prevalent known risk factor for developing AD is carriage of the epsilon4 allele of Apolipoprotein E (ApoE). Carriage of the epsilon2 or epsilon3 allele of ApoE confers protection or no change in risk for AD, respectively. Latent herpes simplex virus type 1 (HSV-1) infection in the brain concurrent with ApoE4 carriage exacerbates risk for AD, suggesting that these two factors interact to promote neuronal dysfunction and degeneration in selective brain areas. Indeed, HSV-1 DNA has been found in regions primarily affected by AD, such as the temporal lobes, hippocampus, and neocortex. We hypothesize that HSV-1 infection in the background of ApoE4, but not ApoE2 or ApoE3, promotes an environment more conducive to neuronal degeneration. To investigate this idea, we have utilized transgenic mice that express human ApoE2, 3, or 4 alleles from astrocytes in a murine ApoE -/- background. We find that carriage of the different ApoE alleles dramatically affects HSV-1 immediate early gene expression as well as the establishment of latency. Both of these factors are poised to impact neuronal viability, inflammation, and viral spread. Our data support the concept that HSV-1 and ApoE4 interact to provide an environment conducive to the development and/or spread of AD.

Memories and anticipations control responding by rats (Rattus norvegicus) in a Pavlovian procedure

In Experiment 1 each rat received two different fixed series of three trials each. The unconditioned stimulus occurred on Trial 1 of one series and on Trial 3 of the other series, all other trials being nonreinforced. Previous Pavlovian investigations have shown that rats can remember the immediately prior reward outcome and anticipate the immediately subsequent reward outcome. Experiment 1 demonstrated that rats could remember and anticipate even more remote reward outcomes. In Experiment 2 two groups received a series of two nonrewarded trials followed by a rewarded trial. It was demonstrated that a change in the conditioned stimulus (CS) from Trial 2 to Trial 3, which occurred in one group, produced weaker responding than in the other group that did not experience such CS change. On the basis of these findings it was suggested that the rats organized the trials of a series into a unit or chunk. This was concluded for two reasons. First, remembering and anticipating remote reward outcomes strongly suggests that responding is being controlled by events extending beyond the current trial. Secondly, the experimental manipulations employed in the Pavlovian situation here are similar to those used in prior human learning and animal instrumental learning investigations concerned with chunking. Thus, it would appear that chunking is a ubiquitous phenomenon appearing in human serial learning (e.g., Bower and Winzenz 1969; Crowder 1976), in animal instrumental learning (e.g., Capaldi 1992; Hulse and Dorsky 1977; Terrace 1987), and now in Pavlovian learning.

CCS/CAR/CANM/CNCS/CanSCMR joint position statement on advanced noninvasive cardiac imaging using positron emission tomography, magnetic resonance imaging and multidetector computed tomographic angiography in the diagnosis and evaluation of ischemic heart disease--executive summary

BACKGROUND

Over the past few decades, advanced imaging modalities with excellent diagnostic capabilities have emerged. The aim of the present position statement was to systematically review existing literature to define Canadian recommendations for their clinical use.

METHODS

A systematic literature review to 2005 was conducted for positron emission tomography (PET), multidetector computed tomographic angiography and magnetic resonance imaging (MRI) in ischemic heart disease. Papers that met the criteria were reviewed for accuracy, prognosis data and study quality. Recommendations were presented to primary and secondary panels of experts, and consensus was achieved.

RESULTS

Indications for PET include detection of coronary artery disease (CAD) with perfusion imaging, and defining viability using fluorodeoxyglucose to determine left ventricular function recovery and/or prognosis after revascularization (class I). Detection of CAD in patients, vessel segments and grafts using computed tomographic angiography was considered class IIa at the time of the literature review. Dobutamine MRI is class I for CAD detection and, along with late gadolinium enhancement MRI, class I for viability detection to predict left ventricular function recovery. Imaging must be performed at institutions and interpreted by physicians with adequate experience and training.

CONCLUSIONS

Cardiac imaging using advanced modalities (PET, multidetector computed tomographic angiography and MRI) is useful for CAD detection, viability definition and, in some cases, prognosis. These modalities complement the more widespread single photon emission computed tomography and echocardiography. Given the rapid evolution of technology, initial guidelines for clinical use will require regular updates. Evaluation of their integration in clinical practice should be ongoing; optimal use will require proper training. A joint effort among specialties is recommended to achieve these goals.

Temporal evolution of mouse striatal gene expression following MPTP injury

The gradual loss of striatal dopamine and dopaminergic neurons residing in the substantia nigra (SN) causes parkinsonism characterized by slow, halting movements, rigidity, and resting tremor when neuronal loss exceeds a threshold of approximately 80%. It is estimated that there is extensive compensation for several years prior to symptom onset, during which vulnerable neurons asynchronously die. Recent evidence would argue that much of the compensatory response of the nigrostriatal system is multimodal including both pre-synaptic and striatal mechanisms. Although parkinsonism may have multiple causes, the classic syndrome, Parkinson's disease (PD), is frequently modeled in small animals by repeated administration of the selective neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Because the MPTP model of PD recapitulates many of the known behavioral and pathological features of human PD, we asked whether the striatal cells of mice treated with MPTP in a semi-chronic paradigm enact a transcriptional program that would help elucidate the response to dopamine denervation. Our findings reveal a time-dependent dysregulation in the striatum of a set of genes whose products may impact both the viability and ability to communicate of dopamine neurons in the SN.

Mycorrhizal mediated feedbacks influence net carbon gain and nutrient uptake in Andropogon gerardii

•  The carbon sink strength of arbuscular mycorrhizal fungi (AMF) was investigated by comparing the growth dynamics of mycorrhizal and nonmycorrhizal Andropogon gerardii plants over a wide range of equivalent tissue phosphorus : nitrogen (P : N) ratios. •  Host growth, apparent photosynthesis (A_net ), net C gain (C_n ) and P and N uptake were evaluated in sequential harvests of mycorrhizal and nonmycorrhizal A. gerardii plants. Response curves were used to assess the effect of assimilate supply on the mycorrhizal symbiosis in relation to the association of C with N and P. •  Mycorrhizal plants had higher C_n than nonmycorrhizal plants at equivalent shoot P : N ratios even though colonization did not affect plant dry mass. The higher C_n in mycorrhizal plants was related to both an increase in specific leaf area and enhanced photosynthesis. The additional carbon gain associated with the mycorrhizal condition was not allocated to root biomass. The C_n in the mycorrhizal plants was positively related to the proportion of active colonization in the roots. •  The calculated difference between C_n values in mycorrhizal and nonmycorrhizal plants, C_diff , appeared to correspond to the sink strength of the AMF and was not an indirect result of enhanced nutrition in mycorrhizal plants.

Behavior and Misbehavior of the Horse

For decades after the discipline of psychiatry had been established as an accepted specialty, many medical schools continued to fail to train their students in the fundamentals of this discipline. Medical students all have at least cursory exposure to psychiatric principles and basic psychology. Unfortunately, the veterinary profession has lagged behind human medicine in this regard. Until recently, veterinary students received no training in animal behavior, and there were no available residencies within our schools for developing board-certified behavioral specialists.

Coping with metastatic melanoma: the last year of life

BACKGROUND

Few longitudinal studies have concurrently investigated cognitive appraisal, coping and psychological adjustment in patients with terminal cancer. This study aimed to (i) consider patterns of change in these variables during the last year of life and (ii) consider covariates associated with patients' psychological adjustment.

METHODS AND PATIENTS

Questionnaires were sent to a cohort of stage IV melanoma patients seen at the Sydney Melanoma Unit between 1991 and 1996, approximately every 3 months, for up to 2 years. A sub-sample of 110 patients completed at least one questionnaire in the last year of life. Repeated measures linear regression was used to model cognitive appraisal, coping and psychological adjustment.

RESULTS

In the last year of life, patients' cognitive appraisal of their disease remained relatively stable, whereas their use of active coping strategies increased (p=0. 04). There was some deterioration in psychological adjustment, particularly in patients' ability to minimize the impact of cancer on daily life (p=0.03), but this effect did not remain significant when patients' level of tiredness was included in the model. Cognitive appraisal, coping style and quality of life indicators were all associated with psychological adjustment.

CONCLUSION

These findings suggest that while patients work hard to actively cope with their disease, they experience increasing levels of tiredness, and deterioration in their mood and ability to function in their daily lives.

Thrombosed giant coronary artery aneurysm presenting as an intracardiac mass

Giant coronary artery aneurysms are rare in adults and are usually found in association with Kawasaki's disease arising in childhood. We report a case of a thrombosed giant right coronary artery aneurysm presenting as an intracardiac mass detected after inferior wall myocardial infarction. Histologic analysis indicated that fibromuscular dysplasia was the underlying cause of the aneurysm.

Advances in the management of dysphagia caused by stroke

This article reviews the advancements that have occurred, primarily in the last decade, in the management and treatment of swallowing disorders related to stroke. An overview of swallowing physiology is given, and interventions, both indirect and direct, are explored. Expanding knowledge, applying techniques from other scientific disciplines, and developing new technologies provide hope for stroke patients who experience dysphagia.

Mycorrhizal status of the genus Carex (Cyperaceae)

The Cyperaceae have generally been considered nonmycorrhizal, although recent evidence suggests that mycotrophy may be considerably more widespread among sedges than was previously realized. This study surveyed 23 species of Carex occurring in upland and wetland habitats in northeastern Illinois. Mycorrhizal infection by arbuscular fungi was found in the roots of 16 species of Carex and appears to occur in response to many factors, both environmental and phylogenetic. While some species appear to be obligately nonmycorrhizal, edaphic influences may be responsible for infection in others. In five of the seven Carex species that were nonmycorrhizal, a novel root character, the presence of bulbous-based root hairs, was identified. The taxonomically patchy distribution of the distinctive root hair trait suggests that these structures may have evolved several times within the genus. Evidence of multiple independent origins of the root hair trait lends support to the hypothesis that root hairs represent an adaptation to nonmycotrophy. Although taxonomic position does seem to be of importance in determining the mycorrhizal dependence of sedges, the pattern may be a patchwork of both mycorrhizal clades and clades that have adapted to the nonmycorrhizal state.

Stroke: current concepts of care

Despite the approval of the use of tissue plasminogen activator for the treatment of acute stroke, less than 10% of all patients with stroke are able to reach a medical facility in time to receive the treatment. This article reviews the current concepts of stroke management and emphasizes the importance of public awareness for the signs and symptoms of stroke and the need for immediate attention when a stroke is suspected.

Benign hypergammaglobulinaemic purpura of Waldenström associated with lymphoid interstitial pneumonitis

A 31-year-old female is described who developed benign hypergammaglobulinaemic purpura and lymphoid interstitial pneumonitis concomitantly. High titre anti-nuclear antibodies were also noted. Several years previously, the patient had developed myasthenia gravis and multiple sclerosis. The present case is an example of multiple medical disorders characterized by immune dysregulation and represents the first reported associated of hypergammaglobulinaemic purpura with lymphoid interstitial pneumonitis.

X-ray imaging and microspectroscopy of plants and fungi

X-ray fluorescence microscopy and microspectroscopy with micrometre spatial resolution and unprecedented capabilities for the study of biological and environmental samples are reported. These new capabilities are a result of both the combination of high-brilliance synchrotron radiation and high-performance X-ray microfocusing optics and the intrinsic advantages of X-rays for elemental mapping and chemical-state imaging. In this paper, these capabilities are illustrated by experimental results on hard X-ray phase-contrast imaging, X-ray fluorescence (XRF) imaging and microspectroscopy of mycorrhizal plant roots and fungi in their natural hydrated state. The XRF microprobe is demonstrated by the simultaneous mapping of the elemental distributions of P, S, K, Ca, Mn, Fe, Ni, Cu and Zn with a spatial resolution of approximately 1 x 3 micron and with an elemental sensitivity of approximately 500 p.p.b. Microspectroscopy with the same spatial resolution is demonstrated by recording near-edge X-ray absorption (XANES) spectra of Mn at a concentration of approximately 3 p.p.m.