Posterior Field Research Articles

Auditory steady-state responses in primary and non-primary regions of the auditory cortex in neonatal ventral hippocampal lesion rats.

Auditory steady-state responses (ASSRs) represent the electrophysiological activity of the auditory nervous system in response to a periodic acoustic stimulus. Spectrogram analysis can reveal the frequency and phase information entrained in ASSRs. Clinically, the ASSR is used to detect abnormalities in electroencephalographs obtained from schizophrenia patients, who show reduced power and phase locking of ASSRs. The neonatal ventral hippocampal lesion (NVHL) rat is a widely used model to investigate the neurodevelopmental mechanisms of schizophrenia. It has been established that NVHL rats exhibit several schizophrenia-like behavioral and molecular abnormalities. However, no clear abnormalities in ASSRs have been reported to date. The present study compared ASSRs of adult NVHL and sham-operated rats. We inserted microelectrodes into the primary auditory cortex (A1) or posterior auditory field (PAF) and recorded the local field potential (LFP) in response to 40- and 80-Hz click train stimuli. Spectrogram analysis was performed to obtain the mean trial power (MTP) and phase-locking factor (PLF) of the click train-evoked LFPs. We found that in the control animals, A1 showed a stronger MTP and PLF of ASSR than PAF, and NVHL operation mainly impaired the ASSR in PAF. Analysis of spike activity also indicated that NVHL operation extended the duration of tone-evoked responses in PAF neurons. Our results reveal, for the first time, that NVHL may distinctly influence the neural activities of primary and non-primary fields of the auditory cortex.

Classifying Heterotaxy Syndrome

Heterotaxy syndrome is a complex set of abnormalities related to abnormal left–right axis patterning. Although rare (occurring in just over 1 in 10 000 live births1), congenital heart defects associated with heterotaxy syndrome carry a disproportionate burden of morbidity and mortality.2,3 Despite numerous investigations on the genetic underpinning, epidemiology, anatomic pathology, diagnostic imaging, and management, agreement regarding the best method to classify patients with heterotaxy continues to elude our field.4 Specifically, a growing body of experience has noted that the 2 most common methods of classifying patients with heterotaxy—based on the status of the spleen or on the morphology of the atrial appendages—is frequently incongruent with the expected pattern of cardiac and noncardiac anomalies,5 is difficult to ascertain clinically, and may not be helpful in guiding clinical management.2–4 See Article by Yim et al In this issue of Circulation: Cardiovascular Imaging , Yim et al6 provide further evidence that the prevailing classification schemes used in heterotaxy syndrome are flawed. In a retrospective analysis of noninvasive imaging data from 114 patients with heterotaxy, they noted that the classic pattern of isomerism was breached in 1 of every 5 patients. Furthermore, they documented the limited clinical utility of relying on atrial appendage morphology or the status of the spleen and …

TomoDirect: an efficient means to deliver radiation at static angles with tomotherapy.

The TomoTherapy Hi-Art II system is able to deliver dynamic intensity-modulated radiation therapy within a helical geometry providing robust conformality and modulation, abrupt dose falloff, and reliable accuracy. A new upgrade named TomoDirect was introduced recently, allowing delivery of radiation at discrete angles with a fixed gantry. We present our preliminary clinical experience with TomoDirect. Three specific clinical contexts were chosen for the implementation of TomoDirect, namely palliation of bone metastasis pain (BP), whole brain radiation therapy for intracranial secondary lesions (WBRT), and adjuvant whole breast radiation therapy after conservative surgery for early stage breast cancer (AWBRT). After appropriate positioning, planning CT, contouring, and plan generation, all patients were treated with the TomoDirect upgrade of the TomoTherapy Hi-Art II system with different doses and fractionation according to clinical decision-making. Between May and December 2010, 41 patients were treated with TomoDirect. Eighteen patients were treated for BP (mainly vertebral metastases) with a predominant posterior field arrangement. Seven patients were treated for WBRT (multiple brain lesions) with a parallel-opposed latero-lateral approach and 16 patients were treated for conventionally fractionated AWBRT mainly with a 2-field tangential approach. Radiation treatments were generally well tolerated and the acute toxicity was mild. While helical tomotherapy allows the delivery of very sophisticated treatment plans, in certain anatomical sites and clinical contexts where the number of beam directions is constrained and supposed not to affect plan quality, TomoDirect might be an efficient means to deliver radiation at static angles with consistent dosimetric and clinical results.

Gata6 restricts Isl1 to the posterior of nascent hindlimb buds through Isl1 cis-regulatory modules

Isl1 is required for two processes during hindlimb development: initiation of the processes directing hindlimb development in the lateral plate mesoderm and configuring posterior hindlimb field in the nascent hindlimb buds. During these processes, Isl1 expression is restricted to the posterior mesenchyme of hindlimb buds. How this dynamic change in Isl1 expression is regulated remains unknown. We found that two evolutionarily conserved sequences, located 3’ to the Isl1 gene, regulate LacZ transgene expression in the hindlimb-forming region in mouse embryos. Both sequences contain GATA binding motifs, and expression pattern analysis identified that Gata6 is expressed in the flank and the anterior portion of nascent hindlimb buds. Recent studies have shown that conditional inactivation of Gata6 in mice causes hindlimb-specific pre-axial polydactyly, indicating a role of Gata6 in anterior-posterior patterning of hindlimbs. We studied whether Gata6 restricts Isl1 in the nascent hindlimb bud through the cis-regulatory modules. In vitro experiments demonstrate that GATA6 binds to the conserved GATA motifs in the cis-regulatory modules. GATA6 repressed expression of a luciferase reporter that contains the cis-regulatory modules by synergizing with Zfpm2. Analyses of Gata6 mutant embryos showed that ISL1 levels are higher in the anterior of nascent hindlimb buds than in wild type. Moreover, we detected a greater number of Isl1-transcribing cells in the anterior of nascent hindlimb buds in Gata6 mutants. Our results support a model in which Gata6 contributes to repression of Isl1 expression in the anterior of nascent hindlimb buds.

Induced cortical responses require developmental sensory experience.

Sensory areas of the cerebral cortex integrate the sensory inputs with the ongoing activity. We studied how complete absence of auditory experience affects this process in a higher mammal model of complete sensory deprivation, the congenitally deaf cat. Cortical responses were elicited by intracochlear electric stimulation using cochlear implants in adult hearing controls and deaf cats. Additionally, in hearing controls, acoustic stimuli were used to assess the effect of stimulus mode (electric versus acoustic) on the cortical responses. We evaluated time-frequency representations of local field potential recorded simultaneously in the primary auditory cortex and a higher-order area, the posterior auditory field, known to be differentially involved in cross-modal (visual) reorganization in deaf cats. The results showed the appearance of evoked (phase-locked) responses at early latencies (<100 ms post-stimulus) and more abundant induced (non-phase-locked) responses at later latencies (>150 ms post-stimulus). In deaf cats, substantially reduced induced responses were observed in overall power as well as duration in both investigated fields. Additionally, a reduction of ongoing alpha band activity was found in the posterior auditory field (but not in primary auditory cortex) of deaf cats. The present study demonstrates that induced activity requires developmental experience and suggests that higher-order areas involved in the cross-modal reorganization show more auditory deficits than primary areas.

Morphological and molecular characterization of two new species of Andracantha (Acanthocephala: Polymorphidae) from New Zealand shags (Phalacrocoracidae) and penguins (Spheniscidae) with a key to the species.

Two new species of Andracantha (Polymorphidae) are described from the intestine of the shags Leucocarbo chalconotus (Gray) and Phalacrocorax punctatus (Sparrman), and the penguin Eudyptula minor (Forster) from southern South Island, New Zealand. Andracantha leucocarboi n. sp. is distinguished from its congeners by having no genital or ventral trunk spines, but possessing a scattering of small spines between the anterior fields of spines. This is the first record of a species of Andracantha from a penguin. Circumbursal papillae are illustrated in a scanning electron micrograph for the first time in the polymorphids. Andracantha sigma n. sp. is distinguished by the sigmoid shape of its largest proboscis hook, hook VIII, and having the ventral field separated from the posterior disc field by an aspinous gap. A Maximum Likelihood tree from cox1 and large ribosomal subunit (LSU) data shows A. leucocarboi n. sp. to be more closely related to A. gravida than A. sigma n. sp. and the genus Andracantha as sister to Corynosoma spp. Genetic distances between species of Andracantha are comparatively large. A key to the species of Andracantha is provided.

Early Interim Results of a Phase 2Clinical Trial of Brachytherapy With Single-Channel Applicator for Cervical Carcinoma

To evaluate whether a single-channel intracavitary applicator ( China Patent number:200710050108.1) which transformed from a traditional tandem applicator with a oval-shaped shield maded of high density alloy has the same clinical efficacy and safety as the standard Fletcher-type applicator in the high-dose-rate(HDR) brachytherapy for carcinoma of the cervix. From December 1st 2011 to December 1st 2014, 112 patients with cervix cancer were randomly assigned to the Patent applicator group (n=54) and the Fletcher applicator group(n=58). All but seven patients with early stage were treated with concurrent cisplatin chemotherapy and external beam radiotherapy (EBRT) followed by HDR brachytherapy. Whole pelvis irradiation was given with 6-MV photons via a four-field box variants or anterior and posterior parallel fields. The standard prescribed dose was 46 to 50 Gy, consisting of 23 to 25 fractions 5 to 6 weeks apart. Five to six fractions with a dose of 7 Gy per fraction of intracavitary brachytherapy at point A once a week were designed for all patients after the third week of pelvic irradiation.This regimen gives a total equivalent dose in 2-Gy fractions (EQD2) of 80-90 Gy to Point A. Chemotherapy was given with intravenous cisplatin 40 mg/m2 once a week during the EBRT. The acute toxicities and the late toxicities were evaluated according to the RTOG grading scale. The Kaplan-Meier analysis was used to compare the overall survival (OS), the progression-Free-Survival (PFS) and the local control (LC). The 2-year OS rate in the two groups was 72.4% in the Fletcher group and 83.2% in the Patent group, respectively. The 2-year PFS rate was 69.0% in the Fletcher group and 79.4% in the Patent group. The 2-year LC rate was 72.4% in the Fletcher group and 79.4% in the Patent group. The seriousness of acute treatment-related toxicities was similar in the two groups. 34 (58.6%) patients in the Fletcher group and 29 (53.7%) in the Patent group had Grade 3–4 hematologic toxicity. No Grade 4 nonhematologic toxicity was observed in the two groups. 5 (8.6%) patients in the Fletcher group and 10 (18.5%) in the Patent group had Grade 3 acute gastrointestinal toxicity. Grade 3 acute rectal reaction and genitourinary effect for the Fletcher group was both 1.7%, and for the Patent group was both 1.9%. The cumulative rate of late rectal complications for Grade 3–4 in the Fletcher group and the Patent group was 5.2% and 1.9%, respectively. The bladder late complications rate of Grade 3–4 was 1.7% for the Fletcher group, and no patients in the Patent group had serious bladder late complications． The early interim results of our study have shown that the patent single-channel intracavitary applicator may be able to provide a protection for the rectum and bladder, and has the same clinical efficacy as the standard Fletcher type three-channel applicator in the HDR brachytherapy for carcinoma of the cervix. Further studies are needed to assess long-term outcomes and associated toxicities.

Effectiveness and toxicity of conventional radiotherapy treatment for painful spinal metastases: a detailed course of side effects after opposing fields versus a single posterior field technique

BackgroundConventional radiotherapy for painful spinal metastases can be delivered with a single posterior-anterior (PA) or two opposed anterior-posterior (APPA) fields. We studied the effectiveness and toxicity of both techniques and studied whether treatment technique was predictive for abdominal and skin toxicity.Patients and methodsWithin the Dutch Bone Metastasis Study, 343 patients received 8 Gray in a single fraction or 24 Gray in six fractions for painful spinal metastases. Treatment technique was not randomized. At baseline and weekly during follow-up, patients reported pain and other physical complaints. Any complaint increasing within 4 weeks after treatment was noted as a side effect. Pain response was calculated according to international standards, taking into account changes in pain score and medication. Repeated measurement analyses and multivariate logistic analyses were performed.ResultsPatients were mainly treated on the thoracic (34%) and lumbar (53%) spine and 73% received a PA field. Pain response was similar between both techniques (74%). In patients treated at the thoraco-lumbar and lumbar spine, with multiple fractions, significantly more abdominal complaints were noticed. In multivariate analysis, radiotherapy technique did not predict for side effects.ConclusionConventional radiotherapy of painful spinal metastases provides limited toxicity. Radiotherapy technique is not an independent predictor of abdominal and skin toxicity of irradiation.

Constraining a terrestrial biosphere model with remotely sensed atmospheric carbon dioxide

We present two novel earth observation products derived from the BESD and EMMA XCO2 products which were respectively retrieved from SCIAMACHY and GOSAT observations within the GreenHouse Gas project of ESA's Climate Change Initiative (GHG-CCI). These products are inferred by a Carbon Cycle Data Assimilation System (CCDAS) and consist of net and gross biosphere-atmosphere fluxes of carbon dioxide on a global 0.5° grid. As a further dataset provided by the CCI, the burnt area product developed by its Fire忌i project was used in the CCDAS to prescribe the emission component from biomass burning. The new flux products are provided with per-pixel uncertainty ranges. Fluxes with uncertainty ranges can also be provided aggregated in space and time, e.g. over given regions or as annual means. For both, posterior flux fields inferred from BESD and EMMA products, transport model simulations show reasonable agreement with the atmospheric carbon dioxide concentration observed at flask sampling stations. This means that the information provided by the terrestrial and transport models, the respective GHG ECV product, the burnt area ECV product, a product of the Fraction of Absorbed Photosynthetically Active Radiation used to drive the model, and the atmospheric flask samples is largely consistent.The most prominent feature in the posterior net flux is the tropical source of CO2 inferred from both products. But for the EMMA product this release, especially over South America, is with 300gC/m2/year much more pronounced than for BESD. This confirms findings by a recent intercomparison of transport inversions using GOSAT data by Houweling et al. (2015). The reason for the larger net flux is increased heterotrophic respiration. For both products the posterior 2010 sink over Europe (without Russia) is in the range of a recent compilation of European flux estimates by Reuter et al. (2016b). The posterior 2010 uptake of Australia (including Oceania) inferred from the EMMA product is 1.3 ± 0.2PgC/year and appears to confirm the high sink also derived from GOSAT by Detmers et al. (2015) over a slightly different period and area. While for some regions (USA, Canada, Europe, Russia, Asia) the one standard deviation uncertainty ranges derived from BESD and EMMA do overlap, for some other regions (Brazil, Africa, Australia) this is not the case. It is not clear yet whether this is due to the uncertainty specifications in the respective products or the handling of uncertainty in the assimilation chain. Assumptions on correlation of observational uncertainty in space and time have a considerable impact on the inferred flux fields (≈ 60gC/m2/year). The effect of adding an uncertainty that approximates the error in the retrieval system is of similar size.

Type III Cells in Anterior Taste Fields Are More Immunohistochemically Diverse Than Those of Posterior Taste Fields in Mice.

Activation of Type III cells in mammalian taste buds is implicated in the transduction of acids (sour) and salty stimuli. Several lines of evidence suggest that function of Type III cells in the anterior taste fields may differ from that of Type III cells in posterior taste fields. Underlying anatomy to support this observation is, however, scant. Most existing immunohistochemical data characterizing this cell type focus on circumvallate taste buds in the posterior tongue. Equivalent data from anterior taste fields-fungiform papillae and soft palate-are lacking. Here, we compare Type III cells in four taste fields: fungiform, soft palate, circumvallate, and foliate in terms of reactivity to four canonical markers of Type III cells: polycystic kidney disease 2-like 1 (PKD2L1), synaptosomal associated protein 25 (SNAP25), serotonin (5-HT), and glutamate decarboxylase 67 (GAD67). Our findings indicate that while PKD2L1, 5-HT, and SNAP25 are highly coincident in posterior taste fields, they diverge in anterior taste fields. In particular, a subset of taste cells expresses PKD2L1 without the synaptic markers, and a subset of SNAP25 cells lacks expression of PKD2L1. In posterior taste fields, GAD67-positive cells are a subset of PKD2L1 expressing taste cells, but anterior taste fields also contain a significant population of GAD67-only expressing cells. These differences in expression patterns may underlie the observed functional differences between anterior and posterior taste fields.

Magnetic Resonance Imaging Patterns of Post-Operative Spinal Infection: Relationship between the Clinical Onset of Infection and the Infection Site.

ObjectiveTo investigate the magnetic resonance imaging (MRI) findings and the patterns of postoperative spinal infection according to the passage of time.MethodsInstitutional review board approval was obtained, and informed consent was not obtained for the retrospective review of patients’ medical records. A total of 43 patients (27 men and 16 women; mean age, 64) diagnosed with postoperative spinal infection were included in this study. We retrospectively reviewed the MRI findings and the medical records and categorized the infection sites based on MRI, i.e., anterior, posterior, and both parts. The duration of the clinical onset from surgery was divided, i.e., acute (≤2 weeks), subacute (2–4 weeks), and late (>4 weeks).ResultsPostoperative spinal infection was involved in the posterior part in 31 (72%), anterior part in two (4.7%), and both parts in 10 patients (23.3%). Abscess or phlegmon in the back muscles and laminectomy site were the most common MRI findings. The number of patients with acute, subacute, and late clinical onset were 35, two, and six, respectively (mean, 33.4 days; range, 1–730 days). The mean duration of the clinical onset was 12 days in the posterior part, 15.2 days in both parts, and 456.5 days in the anterior part.ConclusionPostoperative spinal infection usually occurred within four weeks in the posterior part and over time the infection was considered to spread into the anterior part. For the evaluation of postoperative spinal infection, the posterior surgical field was more important than the vertebral body or the disc space on MRI.

Retinal ganglion cell topography and spatial resolving power in the river hippopotamus (Hippopotamus amphibius).

The river hippopotamus (Hippopotamus amphibius), one of the closest extant relatives to cetaceans, is a large African even-toed ungulate (Artiodactyla) that grazes and has a semiaquatic lifestyle. Given its unusual phenotype, ecology, and evolutionary history, we sought to measure the topographic distribution of retinal ganglion cell density using stereology and retinal wholemounts. We estimated a total of 243,000 ganglion cells of which 3.4% (8,300) comprise alpha cells. The topographic distribution of both total and alpha cells reveal a dual topographic organization of a temporal and nasal area embedded within a well-defined horizontal streak. Using maximum density of total ganglion cells and eye size (35 mm, axial length), we estimated upper limits of spatial resolving power of 8 cycles/deg (temporal area, 1,800 cells/mm2 ), 7.7 cycles/deg (nasal area, 1,700 cells/mm2 ), and 4.2 cycles/deg (horizontal streak, 250 cells/mm2 ). Enhanced resolution of the temporal area toward the frontal visual field may facilitate grazing, while resolution of the horizontal streak and nasal area may help the discrimination of objects (predators, conspecifics) in the lateral and posterior visual fields, respectively. Given the presumed role of alpha cells to detect brisk transient stimuli, their similar distribution to the total ganglion cell population may facilitate the detection of approaching objects in equivalent portions of the visual field. Our finding of a nasal area in the river hippopotamus retina supports the notion that this specialization may enhance visual sampling in the posterior visual field to compensate for limited neck mobility as suggested for rhinoceroses and cetaceans.

Hydrogen Assisted Cracking in Pearlitic Steel Rods: The Role of Residual Stresses Generated by Fatigue Precracking.

Stress corrosion cracking (SCC) of metals is an issue of major concern in engineering since this phenomenon causes many catastrophic failures of structural components in aggressive environments. SCC is even more harmful under cathodic conditions promoting the phenomenon known as hydrogen assisted cracking (HAC), hydrogen assisted fracture (HAF) or hydrogen embrittlement (HE). A common way to assess the susceptibility of a given material to HAC, HAF or HE is to subject a cracked rod to a constant extension rate tension (CERT) test until it fractures in this harsh environment. This paper analyzes the influence of a residual stress field generated by fatigue precracking on the sample’s posterior susceptibility to HAC. To achieve this goal, numerical simulations were carried out of hydrogen diffusion assisted by the stress field. Firstly, a mechanical simulation of the fatigue precracking was developed for revealing the residual stress field after diverse cyclic loading scenarios and posterior stress field evolution during CERT loading. Afterwards, a simulation of hydrogen diffusion assisted by stress was carried out considering the residual stresses after fatigue and the superposed rising stresses caused by CERT loading. Results reveal the key role of the residual stress field after fatigue precracking in the HAC phenomena in cracked steel rods as well as the beneficial effect of compressive residual stress.

Linear energy transfer distributions in the brainstem depending on tumour location in intensity-modulated proton therapy of paediatric cancer

Background: For tumours near organs at risk, there is concern about unintended increase in biological dose from elevated linear energy transfer (LET) at the distal end of treatment fields. The objective of this study was therefore to investigate how different paediatric posterior fossa tumour locations impact LET and biological dose to the brainstem during intensity-modulated proton therapy (IMPT).Material and methods: Multiple IMPT plans were generated for four different simulated tumour locations relative to the brainstem for a five-year-old male patient. A prescribed dose of 59.4 Gy(RBE) was applied to the planning target volumes (PTVs). Plans with two lateral and one posterior non-coplanar fields were created, along with plans with modified field arrangements. The dose-averaged LET (LETd) and the physical dose × RBELET (D × RBELET), where RBELET=1+c × LETd, were calculated using the FLUKA Monte Carlo code. A scaling parameter c was applied to make the RBELET represent variations in the biological effect due to LET.Results: High LETd values surrounded parts of the PTV and encompassed portions of the brainstem. Mean LETd values in the brainstem were 3.2–6.6 keV/μm. The highest absolute brainstem LETd values were seen with the tumour located most distant from the brainstem, whereas lower and more homogeneous LETd values were seen when the tumour invaded the brainstem. In contrast, the highest mean D × RBELET values were found in the latter case (54.0 Gy(RBE)), while the case with largest distance between tumour and brainstem had a mean D × RBELET of 1.8 Gy(RBE).Conclusions: Using IMPT to treat posterior fossa tumours may result in high LETd values within the brainstem, particularly if the tumour volume is separated from the brainstem. However, the D × RBELET was greater for tumours that approached or invaded the brainstem. Changing field angles showed a reduction of LETd and D × RBELET in the brainstem.

Engaging in a tone-detection task differentially modulates neural activity in the auditory cortex, amygdala, and striatum

The relationship between attention and sensory coding is an area of active investigation. Previous studies have revealed that an animal’s behavioral state can play a crucial role in shaping the characteristics of neural responses in the auditory cortex (AC). However, behavioral modulation of auditory response in brain areas outside the AC is not well studied. In this study, we used the same experimental paradigm to examine the effects of attention on neural activity in multiple brain regions including the primary auditory cortex (A1), posterior auditory field (PAF), amygdala (AMY), and striatum (STR). Single-unit spike activity was recorded while cats were actively performing a tone-detection task or passively listening to the same tones. We found that tone-evoked neural responses in A1 were not significantly affected by task-engagement; however, those in PAF and AMY were enhanced, and those in STR were suppressed. The enhanced effect was associated with an improvement of accuracy of tone detection, which was estimated from the spike activity. Additionally, the firing rates of A1 and PAF neurons decreased upon motor response (licking) during the detection task. Our results suggest that attention may have different effects on auditory responsive brain areas depending on their physiological functions.

Upstream regulation for initiation of restricted Shh expression in the chick limb bud.

The organizing center, which serves as a morphogen source, has crucial functions in morphogenesis in animal development. The center is necessarily located in a certain restricted area in the morphogenetic field, and there are several ways in which an organizing center can be restricted. The organizing center for limb morphogenesis, the ZPA (zone of polarizing activity), specifically expresses the Shh gene and is restricted to the posterior region of the developing limb bud. The pre-pattern along the limb anteroposterior axis, provided by anterior Gli3 expression and posterior Hand2 expression, seems insufficient for the initiation of Shh expression restricted to a narrow, small spot in the posterior limb field. Comparison of the spatiotemporal patterns of gene expression between Shh and some candidate genes (Fgf8, Hoxd10, Hoxd11, Tbx2, and Alx4) upstream of Shh expression suggested that a combination of these genes' expression provides the restricted initiation of Shh expression. Taken together with results of functional assays, we propose a model in which positive and negative transcriptional regulatory networks accumulate their functions in the intersection area of their expression regions to provide a restricted spot for the ZPA, the source of morphogen, Shh. Developmental Dynamics 246:417-430, 2017. © 2017 Wiley Periodicals, Inc.

Lung sound analysis helps localize airway inflammation in patients with bronchial asthma.

PurposeAirway inflammation can be detected by lung sound analysis (LSA) at a single point in the posterior lower lung field. We performed LSA at 7 points to examine whether the technique could identify the location of airway inflammation in patients with asthma.Patients and methodsBreath sounds were recorded at 7 points on the body surface of 22 asthmatic subjects. Inspiration sound pressure level (ISPL), expiration sound pressure level (ESPL), and the expiration-to-inspiration sound pressure ratio (E/I) were calculated in 6 frequency bands. The data were analyzed for potential correlation with spirometry, airway hyperresponsiveness (PC20), and fractional exhaled nitric oxide (FeNO).ResultsThe E/I data in the frequency range of 100–400 Hz (E/I low frequency [LF], E/I mid frequency [MF]) were better correlated with the spirometry, PC20, and FeNO values than were the ISPL or ESPL data. The left anterior chest and left posterior lower recording positions were associated with the best correlations (forced expiratory volume in 1 second/forced vital capacity: r=−0.55 and r=−0.58; logPC20: r=−0.46 and r=−0.45; and FeNO: r=0.42 and r=0.46, respectively). The majority of asthmatic subjects with FeNO ≥70 ppb exhibited high E/I MF levels in all lung fields (excluding the trachea) and V50%pred <80%, suggesting inflammation throughout the airway. Asthmatic subjects with FeNO <70 ppb showed high or low E/I MF levels depending on the recording position, indicating uneven airway inflammation.ConclusionE/I LF and E/I MF are more useful LSA parameters for evaluating airway inflammation in bronchial asthma; 7-point lung sound recordings could be used to identify sites of local airway inflammation.

Radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma: dosimetric comparison and risk assessment of solid secondary cancer.

PurposeTo determine the optimal radiotherapy technique for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), we compared the dosimetric parameters and the risk of solid secondary cancer from scattered doses among anterior-posterior/posterior-anterior parallel-opposed fields (AP/PA), anterior, posterior, right, and left lateral fields (4_field), 3-dimensional conformal radiotherapy (3D-CRT) using noncoplanar beams, and intensity-modulated radiotherapy composed of 7 coplanar beams (IMRT_co) and 7 coplanar and noncoplanar beams (IMRT_non).Materials and MethodsWe retrospectively generated 5 planning techniques for 5 patients with gastric MALToma. Homogeneity index (HI), conformity index (CI), and mean doses of the kidney and liver were calculated from the dose-volume histograms. Applied the Biological Effects of Ionizing Radiation VII report to scattered doses, the lifetime attributable risk (LAR) was calculated to estimate the risk of solid secondary cancer.ResultsThe best value of CI was obtained with IMRT, although the HI varied among patients. The mean kidney dose was the highest with AP/PA, followed by 4_field, 3D-CRT, IMRT_co, and IMRT_non. On the other hand, the mean liver dose was the highest with 4_field and the lowest with AP/PA. Compared with 4_field, the LAR for 3D-CRT decreased except the lungs, and the LAR for IMRT_co and IMRT_non increased except the lungs. However, the absolute differences were much lower than <1%.ConclusionTailored RT techniques seem to be beneficial because it could achieve adjacent organ sparing with very small and clinically irrelevant increase of secondary solid cancer risk compared to the conventional techniques.

Auditory-visual integration in fields of the auditory cortex

While multimodal interactions have been known to exist in the early sensory cortices, the response properties and spatiotemporal organization of these interactions are poorly understood. To elucidate the characteristics of multimodal sensory interactions in the cerebral cortex, neuronal responses to visual stimuli with or without auditory stimuli were investigated in core and belt fields of guinea pig auditory cortex using real-time optical imaging with a voltage-sensitive dye. On average, visual responses consisted of short excitation followed by long inhibition. Although visual responses were observed in core and belt fields, there were regional and temporal differences in responses. The most salient visual responses were observed in the caudal belt fields, especially posterior (P) and dorsocaudal belt (DCB) fields. Visual responses emerged first in fields P and DCB and then spread rostroventrally to core and ventrocaudal belt (VCB) fields. Absolute values of positive and negative peak amplitudes of visual responses were both larger in fields P and DCB than in core and VCB fields. When combined visual and auditory stimuli were applied, fields P and DCB were more inhibited than core and VCB fields beginning approximately 110 ms after stimuli. Correspondingly, differences between responses to auditory stimuli alone and combined audiovisual stimuli became larger in fields P and DCB than in core and VCB fields after approximately 110 ms after stimuli. These data indicate that visual influences are most salient in fields P and DCB, which manifest mainly as inhibition, and that they enhance differences in auditory responses among fields.

Effects of multiple breath hold reproducibility on treatment localization and dosimetric accuracy in radiotherapy of left-sided breast cancer with voluntary deep inspiration breath hold technique

The purpose of this study was to investigate the effects of breath hold reproducibility on positional and dosimetric errors in radiotherapy of patients with left-sided breast cancer (LSBC) treated with voluntary deep inspiration breath hold (vDIBH) technique. Clinical data from 2 groups of patients with LSBC were retrospectively investigated: (1) those irradiated for the whole breast only (WB group, n = 20) using typically from 3 to 5 breath holds per treatment session and (2) those irradiated simultaneously also for supraclavicular lymph nodes (WB + SLN group, n = 27) using from 7 to 9 breath holds per fraction. Setup and field images (n = 1365) from tangential breast fields, and anterior and posterior lymph node fields were analyzed to obtain total, inter-, and intrafractional residual positional errors of the chest wall and clavicle. The dosimetric effect of intrafractional positional errors was investigated at the abutment level of breast and lymph node fields. The total systematic setup error in the longitudinal (superior-inferior [SI]) direction was 1.4 and 1.9 mm (1 standard deviation, p = 0.049) for the WB and WB + SLN groups, respectively, whereas in the anterior/lateral direction, the error was 1.2 mm for both groups. In the SI direction, the systematic intrafractional error was also larger in the WB + SLN group (1.9 vs 1.1 mm, p = 0.003). The latter positional errors correlated moderately (ρ = 0.51) with the number of breath holds. Mean intrafractional errors of at least 2 mm were observed for 38% of the patients in the WB + SLN group. These errors resulted in a dosimetric error from 8.3% to 10.1% (1 cc). The total localization errors and needed setup margins were wider for the WB + SLN group, due to increased amount of breath holds in treatment session. Mean intrafraction movements ≥ 2 mm were shown to occur with this patient group in the SI direction, requiring intrafractional positional monitoring and corrective actions in daily practice.