Enhancing Clinical Accuracy in DIBH Pattern Detection with a Combined Ultrasonic and IR Sensor System

PURPOSE/OBJECTIVE(S)

This study aimed to develop a DIBH monitoring system using IR (Infrared- VL6180X Time of Flight) distance sensors and a microcontroller, and to demonstrate its functionality and performance in various irregular free and DIBH breathings from the left breast and lung patients.

MATERIALS/METHODS

A total of ten patients who performed DIBH breathing for treatment planning and optimized treatment delivery were randomly selected for the study. The breathing motion of the system was tested using an RPM (Real-Time Positioning Management) phantom. The IR sensors were interfaced with an Arduino microcontroller, and a body phantom was used to mimic the DIBH pattern on a CT scan. The detector holder was mounted perpendicularly between the xiphoid and umbilicus, with the ability to compensate for various patient body habitus and adapt to clinical setups. The plastic devices were 3D printed, and the sensors were mounted approximately 100mm apart to receive directed echo signals and prevent unwanted signals from scattering.

RESULTS

The IR sensor DIBH system was able to detect and record the patient's breathing pattern in real-time. The IR sensor showed better visualization of breathing rhythm with fewer fluctuations and reduced noise than the previous ultrasonic sensor system. The breathing amplitude and duration for the patients were compared to our treatment planning of Varian Eclipse and verified in TrueBeam's Breath-Hold Gating mode. The amplitude and duration from the primary study were measured to ±5mm, including 3mm sensor noise level and ±1.5 second.

CONCLUSION

The IR sensor DIBH system demonstrated better performance compared to the ultrasonic sensor, with a better visualization of breathing rhythm and reduced fluctuations and noise. It provided a clinically acceptable DIBH pattern for monitoring chest and abdominal motion in patients with irregular breathing. The findings of this study have the potential to enhance clinical accuracy in radiation therapy treatment planning and delivery for patients undergoing DIBH.

Genetic approach identifies distinct asthma pathways in overweight vs normal weight children

The pathogenesis of asthma in the context of excess body weight may be distinct from asthma that develops in normal weight children. The study's objective was to explore the biology of asthma in the context of obesity and normal weight status using genetic methodologies. Associations between asthma and SNPs in 49 genes were assessed, as well as, interactions between SNPs and overweight status in child participants of the Greater Cincinnati Pediatric Clinic Repository. Asthma was significantly associated with weight (OR = 1.38; P = 0.037). The number of genes and the magnitude of their associations with asthma were notably greater when considering overweight children alone vs normal weight and overweight children together. When considering weight, distinct sets of asthma-associated genes were observed, many times with opposing effects. We demonstrated that the underlying heterogeneity of asthma is likely due in part to distinct pathogenetic pathways that depend on preceding/comorbid overweight and/or allergy. It is therefore important to consider both obesity and asthma when conducting studies of asthma.

Matrix-dependent mechanism of neutrophil-mediated release and activation of matrix metalloproteinase 9 in myocardial ischemia/reperfusion

BACKGROUND

A key component of reperfusion of myocardial infarction is an immediate inflammatory response, which enhances tissue repair. Matrix turnover is crucial to tissue repair, and matrix metalloproteinases (MMPs) are key enzymes involved in matrix degradation. The hypothesis tested is that one inflammation-based effector of tissue repair is the secretion and activation of MMP-9 by infiltrating neutrophils.

METHODS AND RESULTS

Cardiac lymph and tissue were assayed for atent and active MMP-2 and MMP-9 by zymography and immunochemistry. Dual-labeling immunofluorescence determined the cellular source of MMP-9 protein. Isolated canine neutrophils were incubated with preischemic and postischemic cardiac lymph in the presence and absence of collagen-fibronectin pads, and the supernatants were assayed for latent and active MMP-9. MMP-9 increased during the first hours of reperfusion in both lymph supernatants and myocardial extracts, and this increase was of neutrophil origin. MMP-9 in the cardiac lymph remained latent but was activatable. In contrast, MMP-9 in the myocardium was in both latent and active forms. In situ zymography demonstrated that activated MMP-9 surrounded the infiltrated neutrophils. When postischemic cardiac lymph was incubated with neutrophils in vitro, MMP-9 secretion and activation occurred only in the presence of a collagen-fibronectin substrate; preischemic cardiac lymph did not induce significant secretion or activation.

CONCLUSIONS

Infiltrating neutrophils are an early source of MMP-9 after reperfusion, and a portion of MMP-9 in the myocardium is active. Infiltrating neutrophils may localize MMP-9 activation by secreting MMP-9 and as a source of activating proteases.

MMP inhibition as a potential therapeutic strategy for CHF

Congestive heart failure (CHF) is a leading cause of death in developed countries and its prevalence is increasing throughout the world. Progressive left ventricular dilation and contractile dysfunction cause most cases of CHF. Recent therapies have targeted the neurohumoral system, with few therapies directed toward the actual dilation process; however, emerging data indicate that certain members of the family of metalloenzymes, the matrix metalloproteinases, are not only associated with ventricular dilation, but may actually mediate the dilation process. Because these enzymes are extracellular and are pharmacologic targets, matrix metalloproteinase inhibition is a novel potential therapy for delaying or preventing heart failure.

Targeted deletion of matrix metalloproteinase-9 attenuates left ventricular enlargement and collagen accumulation after experimental myocardial infarction

Matrix metalloproteinase-9 (MMP-9) is prominently overexpressed after myocardial infarction (MI). We tested the hypothesis that mice with targeted deletion of MMP9 have less left ventricular (LV) dilation after experimental MI than do sibling wild-type (WT) mice. Animals that survived ligation of the left coronary artery underwent echocardiographic studies after MI; all analyses were performed without knowledge of mouse genotype. By day 8, MMP9 knockout (KO) mice had significantly smaller increases in end-diastolic and end-systolic ventricular dimensions at both midpapillary and apical levels, compared with infarcted WT mice; these differences persisted at 15 days after MI. MMP-9 KO mice had less collagen accumulation in the infarcted area than did WT mice, and they showed enhanced expression of MMP-2, MMP-13, and TIMP-1 and a reduced number of macrophages. We conclude that targeted deletion of the MMP9 gene attenuates LV dilation after experimental MI in mice. The decrease in collagen accumulation and the enhanced expression of other MMPs suggest that MMP-9 plays a prominent role in extracellular matrix remodeling after MI.

Magnetoelastic sensors in combination with nanometer-scale honeycombed thin film ceramic TiO2 for remote query measurement of humidity

Ribbonlike magnetoelastic sensors can be considered the magnetic analog of an acoustic bell; in response to an externally applied magnetic field impulse the sensors emit magnetic flux with a characteristic resonant frequency. The magnetic flux can be detected external to the test area using a pick-up coil, enabling query remote monitoring of the sensor. The characteristic resonant frequency of a magnetoelastic sensor changes in response to mass loads. [L.D. Landau and E. M. Lifshitz, Theory of Elasticity, 3rd ed. (Pergamon, New York, 1986). p. 100].Therefore, remote query chemical sensors can be fabricated by combining the magnetoelastic sensors with a mass changing, chemically responsive layer. In this work magnetoelastic sensors are coated with humidity-sensitive thin films of ceramic, nanodimensionally porous TiO2 to make remote query humidity sensors.

HLA-B15 peptide ligands are preferentially anchored at their C termini

Therapies to elicit protective CTL require the selection of pathogen- and tumor-derived peptide ligands for presentation by MHC class I molecules. Edman sequencing of class I peptide pools generates "motifs" that indicate that nonameric ligands bearing conserved position 2 (P2) and P9 anchors provide the optimal search parameters for selecting immunogenic epitopes. To determine how well a motif represents its individual constituents, we used a hollow-fiber peptide production scheme followed by the mapping of endogenously processed class I peptide ligands through reverse-phase HPLC and mass spectrometry. Systematically mapping and characterizing ligands from B*1508, B*1501, B*1503, and B*1510 demonstrate that the peptides bound by these B15 allotypes i) vary in length from 7 to 12 residues, and ii) are more conserved at their C termini than their N-proximal P2 anchors. Comparative peptide mapping of these B15 allotypes further pinpoints endogenously processed ligands that bind to the allotypes B*1508, B*1501, and B*1503, but not B*1510. Overlapping peptide ligands are successful in binding to B*1501, B*1503, and B*1508 because these B15 allotypes share identical C-terminal anchoring pockets whereas B*1510 is divergent in the C-terminal pocket. Therefore, endogenous peptide loading into the B15 allotypes requires that a conserved C terminus be anchored in the appropriate specificity pocket while N-proximal anchors are more flexible in their location and sequence. Queries for overlapping and allele-specific peptide ligands may thus be contingent on a conserved C-terminal anchor.

Complexity among constituents of the HLA-B*1501 peptide motif

Analysis of peptides derived from HLA class I molecules indicates that thousands of unique peptides are bound by a single molecular type, and sequence examination of the pooled constituents yields a motif which collectively defines the peptides bound by a given class I molecule. Motifs resulting from pooled sequencing are then used to infer whether particular viral and tumor protein fragments might serve as class I-presented peptide therapeutics. Still undetermined from a pooled motif is the breadth or range of peptides in the population which are brought together to form the pooled motif, and it is therefore not yet known how representative of the population a pooled motif is. By employing hollow fiber bioreactors for large-scale production of HLA class I molecules, sufficient peptides are produced to investigate individual subsets of peptides comprising a motif. Edman sequencing and mass spectrometric analysis of peptides eluted from HLA-B*1501 reveal that many peptide sequences fail to align with either the N- or C-terminal anchors predicted for the B*1501 peptide motif through whole pool sequencing. These analyses further reveal auxiliary anchors not previously detected and peptides significantly larger and smaller than the predicted nonamer, ranging from 6 to 12 amino acids in length. These results demonstrate that constituents of the B*1501 peptide pool vary markedly in comparison with one another and therefore in comparison with previously established B*1501 motifs, and such complexity indicates that many of the peptide ligands presented to CTL cannot be predicted using class I consensus motifs as search criteria.

Large-scale production of class I bound peptides: assigning a signature to HLA-B*1501

A peptide-based vaccine must be bound and presented by major histocompatibility complex class I molecules to elicit a CD8(+) T-cell response. Because class I HLA molecules are highly polymorphic, it has yet to be established how well a vaccine peptide that stimulates one individual's CD8(+) cytotoxic T lymphocytes will be presented by a second individual's different class I molecules. Therefore, to facilitate precise comparisons of class I peptide binding overlaps, we uniquely combined hollow-fiber bioreactors and mass spectrometry to assign precise peptide binding signatures to individual class I HLA molecules. In applying this strategy to HLA-B*1501, we isolated milligram quantities of B*1501-bound peptides and mapped them using mass spectrometry. Repeated analyses consistently assign the same peptide binding signature to B*1501; the degree of peptide binding overlap between any two class I molecules can thus be determined through comparison of their peptide signatures.

Relation of perioperative deaths to hospital volume among patients undergoing pancreatic resection for malignancy

OBJECTIVE

The authors examined the effect of hospital and surgeon volume on perioperative mortality rates after pancreatic resection for the treatment of pancreatic cancer.

METHODS

Discharge abstracts from 1972 patients who had undergone pancreaticoduodenectomy or total pancreatectomy for malignancy in New York State between 1984 and 1991 were obtained from the Statewide Planning and Research Cooperative System. Logistic regression analysis was used to determine the relationship between hospital and surgeon experience to perioperative outcome.

RESULTS

More than 75% of patients underwent resection at minimal-volume (fewer than 10 cases) or low-volume (10-50 cases) centers (defined as hospitals in which a minimal number of resections were performed in a given year), and these hospitals represented 98% of the institutions treating peripancreatic cancer. The two high-volume hospitals (more than 81 cases) demonstrated a significantly lower perioperative mortality rate (4.0%) compared with the minimal- (21.8%) and low-volume (12.3%) hospitals (p < 0.001). The perioperative mortality rate was 15.5% for low-volume (fewer than 9 cases) surgeons (defined as surgeons who had performed a minimal number of resections in any hospital in a given year) (n = 687) compared with 4.7% for high-volume (more than 41 cases) pancreatic surgeons (n = 4) (p < 0.001). Logistic regression analysis demonstrated that perioperative death is significantly (p < 0.05) related to hospital volume, but the surgeon's experience is not significantly related to perioperative deaths when hospital volume is controlled.

CONCLUSIONS

These data support a defined minimum hospital experience for elective pancreatectomy for malignancy to minimize perioperative deaths.

Family nurse practitioner clinical competencies in alcohol and substance use

The prevalence of substance use among patients presenting to primary health care settings mandates clinical competency in the area for nurse practitioners (NPs). An educational intervention with an evaluation component is described. The effect of incorporating substance use content into a Family Nurse Practitioner (FNP) curriculum was tested with a convenience sample of 16 FNP students and 8 practicing NPs. Students' knowledge increased significantly; however, differences in students' and practicing NPs' knowledge did not reach significance. Students' clinical competency increased significantly, as demonstrated by standardized patient clinical evaluations, and was significantly better than the practicing NPs in the skill domains of evaluation and record keeping. Educational intervention can improve NP identification of substance-abusing patients in primary health care settings.

Management of learning disability in the general hospital

Learning-disabled people need to use the same medical services as the rest of the population. Once referred to a general hospital their diagnosis and treatment must take into account any special needs generated by their disability. This article describes the way in which this can be achieved and the resource implications.

Abdominal assessment

Overall assessment of the orthopaedic patient can be enhanced when the nurse has knowledge of abdominal assessment, including an understanding of abdominal anatomy, history taking, and physical assessment. The assessment process should culminate in the appropriate documentation of the nurse's findings. This article provides a concrete, thorough overview of the nursing assessment of the abdomen.