Space-Time Structured Plasma Waves

Electrostatic waves play a critical role in nearly every branch of plasma physics from fusion to advanced accelerators, to astro, solar, and ionospheric physics. The properties of planar electrostatic waves are fully determined by the plasma conditions, such as density, temperature, ionization state, or details of the distribution functions. Here we demonstrate that electrostatic wave packets structured with space-time correlations can have properties that are independent of the plasma conditions. For instance, an appropriately structured electrostatic wave packet can travel at any group velocity, even backward with respect to its phase fronts, while maintaining a localized energy density. These linear, propagation-invariant wave packets can be constructed with or without orbital angular momentum by superposing natural modes of the plasma and can be ponderomotively excited by space-time structured laser pulses like the flying focus.

Does the SORG Machine-learning Algorithm for Extremity Metastases Generalize to a Contemporary Cohort of Patients? Temporal Validation From 2016 to 2020

BACKGROUND

The ability to predict survival accurately in patients with osseous metastatic disease of the extremities is vital for patient counseling and guiding surgical intervention. We, the Skeletal Oncology Research Group (SORG), previously developed a machine-learning algorithm (MLA) based on data from 1999 to 2016 to predict 90-day and 1-year survival of surgically treated patients with extremity bone metastasis. As treatment regimens for oncology patients continue to evolve, this SORG MLA-driven probability calculator requires temporal reassessment of its accuracy.

QUESTION/PURPOSE

Does the SORG-MLA accurately predict 90-day and 1-year survival in patients who receive surgical treatment for a metastatic long-bone lesion in a more recent cohort of patients treated between 2016 and 2020?

METHODS

Between 2017 and 2021, we identified 674 patients 18 years and older through the ICD codes for secondary malignant neoplasm of bone and bone marrow and CPT codes for completed pathologic fractures or prophylactic treatment of an impending fracture. We excluded 40% (268 of 674) of patients, including 18% (118) who did not receive surgery; 11% (72) who had metastases in places other than the long bones of the extremities; 3% (23) who received treatment other than intramedullary nailing, endoprosthetic reconstruction, or dynamic hip screw; 3% (23) who underwent revision surgery, 3% (17) in whom there was no tumor, and 2% (15) who were lost to follow-up within 1 year. Temporal validation was performed using data on 406 patients treated surgically for bony metastatic disease of the extremities from 2016 to 2020 at the same two institutions where the MLA was developed. Variables used to predict survival in the SORG algorithm included perioperative laboratory values, tumor characteristics, and general demographics. To assess the models' discrimination, we computed the c-statistic, commonly referred to as the area under the receiver operating characteristic (AUC) curve for binary classification. This value ranged from 0.5 (representing chance-level performance) to 1.0 (indicating excellent discrimination) Generally, an AUC of 0.75 is considered high enough for use in clinical practice. To evaluate the agreement between predicted and observed outcomes, a calibration plot was used, and the calibration slope and intercept were calculated. Perfect calibration would result in a slope of 1 and intercept of 0. For overall performance, the Brier score and null-model Brier score were determined. The Brier score can range from 0 (representing perfect prediction) to 1 (indicating the poorest prediction). Proper interpretation of the Brier score necessitates a comparison with the null-model Brier score, which represents the score for an algorithm that predicts a probability equal to the population prevalence of the outcome for each patient. Finally, a decision curve analysis was conducted to compare the potential net benefit of the algorithm with other decision-support methods, such as treating all or none of the patients. Overall, 90-day and 1-year mortality were lower in the temporal validation cohort than in the development cohort (90 day: 23% versus 28%; p < 0.001, and 1 year: 51% versus 59%; p<0.001).

RESULTS

Overall survival of the patients in the validation cohort improved from 28% mortality at the 90-day timepoint in the cohort on which the model was trained to 23%, and 59% mortality at the 1-year timepoint to 51%. The AUC was 0.78 (95% CI 0.72 to 0.82) for 90-day survival and 0.75 (95% CI 0.70 to 0.79) for 1-year survival, indicating the model could distinguish the two outcomes reasonably. For the 90-day model, the calibration slope was 0.71 (95% CI 0.53 to 0.89), and the intercept was -0.66 (95% CI -0.94 to -0.39), suggesting the predicted risks were overly extreme, and that in general, the risk of the observed outcome was overestimated. For the 1-year model, the calibration slope was 0.73 (95% CI 0.56 to 0.91) and the intercept was -0.67 (95% CI -0.90 to -0.43). With respect to overall performance, the model's Brier scores for the 90-day and 1-year models were 0.16 and 0.22. These scores were higher than the Brier scores of internal validation of the development study (0.13 and 0.14) models, indicating the models' performance has declined over time.

CONCLUSION

The SORG MLA to predict survival after surgical treatment of extremity metastatic disease showed decreased performance on temporal validation. Moreover, in patients undergoing innovative immunotherapy, the possibility of mortality risk was overestimated in varying severity. Clinicians should be aware of this overestimation and discount the prediction of the SORG MLA according to their own experience with this patient population. Generally, these results show that temporal reassessment of these MLA-driven probability calculators is of paramount importance because the predictive performance may decline over time as treatment regimens evolve. The SORG-MLA is available as a freely accessible internet application at https://sorg-apps.shinyapps.io/extremitymetssurvival/ .Level of Evidence Level III, prognostic study.

Erratum: Dephasingless Laser Wakefield Acceleration [Phys. Rev. Lett. 124, 134802 (2020)]

This corrects the article DOI: 10.1103/PhysRevLett.124.134802.

Analytical Bayesian approach for the design of surveillance and control programs to assess pest-eradication success

Large invasive species eradication programs are undertaken to protect native biodiversity and agriculture. Programs are typically followed by a series of surveys to assess the likelihood of eradication success and, when residual pests are detected, small-scale control or 'mop-ups' are implemented to eliminate these infestations. Further surveys follow to confirm absence with 'freedom' declared when a target probability of absence is reached. Such biosecurity programs comprise many interacting processes - stochastic biological processes including growth, and response and control interventions - and are an important component of post-border biosecurity. Statistical frameworks formulated to contribute to the design and efficiency of these surveillance and control programs are few and, those available, rely on the simulation of the component processes. In this paper we formulate an analytical Bayesian framework for a general biosecurity program with multiple components to assess pest-eradication success. Our model incorporates stochastic growth and detection processes, and several pest control mechanisms. Survey results and economic considerations are also taken into account to support a range of biosecurity management decisions. Using a case study we demonstrate that solutions match published simulation results and extend the available analysis. Principally, we show how analytical solutions can offer a powerful tool to support the design of effective and cost-efficient biosecurity systems, and we establish some general principles that guide and contribute to robust design.

Periprosthetic knee infection after benign tumor excision complicated by carbapenem resistant Enterobacteriaceae: A case report

Introduction

Periprosthetic joint infection (PJI) is a major complication after total knee arthroscopy. Enterobacter is a rare cause of PJI.

Case presentation

We present a 65 year old Caucasian man who presented with acute right knee PJI with Carbapenem-resistant Enterobacteriaceae (CRE) two months after undergoing right knee intra-articular mass removal with endoprosthetic reconstruction. The periprosthetic joint infection (PJI) was treated with revision with 1-stage static spacer and IV meropenem.

Discussion

CRE is an uncommon cause of PJI, but when it does occur, it commonly infects patients who are immunosuppressed or have specific risk factors. For an immunocompetent patient with CRE PJI, we suggest further workup for other systemic disease.

Conclusion

This case demonstrates the importance of early diagnosis and treatment of CRE joint infections and the need for a multidisciplinary approach that includes aggressive surgical intervention and tailored antimicrobial therapy.

•

We present a case of acute right knee periprosthetic joint infection with Carbapenem-resistant Enterobacteriaceae (CRE) after patient underwent intra-articular mass removal with endoprosthetic reconstruction.

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Further workup for systemic disease is strongly recommended in immunocompetent patients presenting with CRE joint infection.

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Management of CRE joint infections is complicated and requires a multidisciplinary approach with aggressive surgical intervention and focused antimicrobial therapy.

Nonlinear Thomson scattering with ponderomotive control

In nonlinear Thomson scattering, a relativistic electron reradiates the photons of a laser pulse, converting optical light to x rays or beyond. While this extreme frequency conversion offers a promising source for probing high-energy-density materials and driving uncharted regimes of nonlinear quantum electrodynamics, conventional nonlinear Thomson scattering has inherent trade-offs in its scaling with laser intensity. Here we discover that the ponderomotive control afforded by spatiotemporal pulse shaping enables regimes of nonlinear Thomson scattering that substantially enhance the scaling of the radiated power, emission angle, and frequency with laser intensity. By appropriately setting the velocity of the intensity peak, a spatiotemporally shaped pulse can increase the power radiated by orders of magnitude. The enhanced scaling with laser intensity allows for operation at significantly lower electron energies or intensities.

Analytical Bayesian models to quantify pest eradication success or species absence using zero-sighting records

It is not possible to establish the absence of a population with certainty using imperfect zero-sighting records, but absence can be inferred. In this paper we use Bayesian methods to formulate analytical inferred distributions and statistics. When such formulations are available, they offer a highly efficient and powerful means of analysis. Our purpose is to provide accessible and versatile formulations to support an assessment of population absence for management decisions, using data from a series of regular and targeted surveys with zero-sightings. The stochastic processes considered here are prior population size, growth and imperfect detection, which are combined into a single distribution with sufficient flexibility to accommodate alternative distributions for each of the driving processes. Analytical solutions formulated include the inferred mean and variance for population size or number of infested survey-units, the probability of absence, the probability of a series of negative surveys conditional on presence, and the probability a population is first detected in a given survey, although we also formulate other statistics and provide explicit thresholds designed to support management decisions. Our formulation and results are straightforward to apply and provide insight into the nonlinear interactions and general characteristics of such systems. Although motivated by an assessment of population absence following a pest eradication program, results are also relevant to the status of threatened species, to 'proof-of-freedom' requirements for trade, and for inferring population size when a population is first detected.

Vacuum acceleration of electrons in a dynamic laser pulse

A planar laser pulse propagating in vacuum can exhibit an extremely large ponderomotive force. This force, however, cannot impart net energy to an electron: As the pulse overtakes the electron, the initial impulse from its rising edge is completely undone by an equal and opposite impulse from its trailing edge. Here we show that planarlike "flying focus" pulses can break this symmetry, imparting relativistic energies to electrons. The intensity peak of a flying focus-a moving focal point resulting from a chirped laser pulse focused by a chromatic lens-can travel at any subluminal velocity, forward or backward. As a result, an electron can gain enough momentum in the rising edge of the intensity peak to outrun and avoid the trailing edge. Accelerating the intensity peak can further boost the momentum gain. Theory and simulations demonstrate that these dynamic intensity peaks can backwards accelerate electrons to the MeV energies required for radiation and electron diffraction probes of high energy density materials.

Dephasingless Laser Wakefield Acceleration

Laser wakefield accelerators (LWFAs) produce extremely high gradients enabling compact accelerators and radiation sources but face design limitations, such as dephasing, occurring when trapped electrons outrun the accelerating phase of the wakefield. Here we combine spherical aberration with a novel cylindrically symmetric echelon optic to spatiotemporally structure an ultrashort, high-intensity laser pulse that can overcome dephasing by propagating at any velocity over any distance. The ponderomotive force of the spatiotemporally shaped pulse can drive a wakefield with a phase velocity equal to the speed of light in vacuum, preventing trapped electrons from outrunning the wake. Simulations in the linear regime and scaling laws in the bubble regime illustrate that this dephasingless LWFA can accelerate electrons to high energies in much shorter distances than a traditional LWFA-a single 4.5 m stage can accelerate electrons to TeV energies without the need for guiding structures.

The PTPN13 Y2081D (T>G) (rs989902) polymorphism is associated with an increased risk of sporadic colorectal cancer

AIM

Colorectal cancer (CRC) is one of the most common cancers worldwide and, although the majority of cases are sporadic, its development and progression depends on a range of factors: environmental, genetic and epigenetic. A variety of genetic pathways have been described as being crucial in CRC, including protein tyrosine phosphatases (PTPs). PTPN13 (also called FAP-1) is a non-receptor PTP and interacts with a number of important components of growth and apoptosis pathways. It is also involved in the inhibition of Fas-induced apoptosis.

METHOD

The single nucleotide polymorphism genotype at Y2081D (T>G) (rs989902) of PTPN13 exon 39 was determined in DNA extracted from blood samples from 174 sporadic CRC patients and 176 healthy individuals. Also, a meta-analysis was performed based on three articles accessed via the PubMed and ResearchGate databases.

RESULTS

The risk of CRC was 2.087 times greater for patients with the GG genotype than for those with the TT genotype (P = 0.0475). In the meta-analysis, a significantly increased risk of cancer associated with the G allele was observed in the squamous cell carcinoma of the head and neck subgroup (TT vs GG+GT, OR 1.23, 95% CI [1.02, 1.47], P = 0.0258), and a significantly decreased risk in the breast cancer subgroup (TT vs GG+GT, OR 0.63, 95% CI [0.41, 0.96], P = 0.0334) and in the CRC subgroup (GT+TT vs GG, OR 0.51, 95% CI [0.41, 0.95], P = 0.0333).

CONCLUSION

PTPN13 rs989902 is significantly associated with the risk of CRC in the Polish population. Given that this report provides the first evidence of an association of PTPN13 rs989902 with the risk of CRC in a Caucasian population, further large scale studies are necessary to confirm this finding.

Physical activity and the risk of Barrett's esophagus

Physical activity either directly or through influencing body fat may affect the risk of Barrett's esophagus (BE). However, the effect of physical activity on the risk of developing BE has not been examined. We conducted a case-control study among consecutive eligible patients either scheduled for elective endoscopy or recruited from primary care clinics to undergo a study endoscopy. Study participants completed the International Physical Activity Questionnaire (IPAQ) short form that measures physical activity during the past 7 days. We categorized level of physical activity by low, moderate, or high and estimated metabolic equivalent minutes per week (MET min/week). We calculated odds ratios (ORs) using logistic regression models and adjusted for age, sex, race, gastroesophageal reflux disease symptoms, Helicobacter pylori infection, body mass index, and waist-to-hip ratio. There were 307 cases with BE and 1724 controls (1262 from endoscopy and 462 from the primary care clinic) with IPAQ information. BE cases were more likely to be in the high-category physical activity category than controls (14.3% vs. 11.5% P = 0.08). However, there were no differences in the overall average MET min/week for walking between BE cases and controls (909 vs. 561; P = 0.16), with similar findings among those with moderate activity (1094 vs. 755, P = 0.18) or vigorous activity (784 vs. 826, P = 0.93). In multivariable logistic regression, physical activity level was not significantly associated with BE (OR = 1.19, 95% confidence interval: 0.82-1.73). Recent amount and intensity of physical activity are not associated with a reduction in the risk of BE. Studies are required to examine the long-term effects of physical activity.

Effectiveness of 0.05% oxymetazoline (Vicks Sinex Micromist®) nasal spray in the treatment of objective nasal congestion demonstrated to 12 h post-administration by magnetic resonance imaging

INTRODUCTION

This study aimed to assess the qualitative and quantitative utility of MRI imaging to illustrate the magnitude and duration of the effect of a standard 100 μg dose of oxymetazoline in a commercially available formulation that also contains aromatic oils.

METHODS

This was a randomized, open label, single dose, parallel group study in 21 adult male and female subjects who reported moderate to severe nasal congestion due to acute upper respiratory tract infection or hay fever. MRI scans were acquired using a 3T Philips Achieva scanner with a 16 channel head receive coil. High resolution MRI scans of the nasal turbinates were obtained immediately prior to dosing (baseline) and at approximately 1, 8, 10, 11, and 12 h after dosing. The efficacy variables of primary interest were inferior turbinate total volume at 8 and 12 h post-dosing. The secondary efficacy variables analysed were inferior turbinate total volume at 1, 10, and 11 h post-dosing, middle turbinate total volume at 1, 8, 10, 11, and 12 h post-dosing.

RESULTS

Changes from baseline volumes measured for the inferior and middle turbinates of subjects receiving the oxymetazoline formulation showed significant (P < 0.05) decreases at all times up to and including 12 h post-administration. No significant decreases from baseline were detected in subjects receiving a sham 'spray' (untreated control - spray bottles with no spray solution). Statistical ANCOVA results of inferior and middle turbinate volume indicated significant differences (P < 0.05) at all measurement points up to and including 12 h post-administration between the oxymetazoline treatment group and the untreated control with the only exception the middle turbinate volume at 10 h (P = 0.0896). The significant changes were likely to be clinically relevant though this was not measured in the study. No AEs were reported during this study and no other safety evaluations were made.

CONCLUSIONS

This study showed that MRI assessment of nasal congestion in human volunteers is a robust, repeatable and viable measurement technique. The application of a 100 μg Vicks Sinex Micromist(®) nasal decongestant (0.05% oxymetazoline solution) delivered a highly significant reduction in inferior and middle turbinate volumes compared with the application of a control, measurable by the MRI method up to and including a 12 h post-dose scan.

Randomised clinical trial: delayed-release oral mesalazine 4.8 g/day vs. 2.4 g/day in endoscopic mucosal healing--ASCEND I and II combined analysis

BACKGROUND

Recent studies have focused on the importance of mucosal healing in ulcerative colitis (UC). However, it was still unclear whether higher doses of delayed-release mesalazine (mesalamine) could provide additional benefit.

AIM

To examine how two doses of delayed-release mesalazine (4.8 g/day and 2.4 g/day) from ASCEND I and II compare in their relative ability to heal colonic mucosa over time.

METHODS

Primary data from two prospective 6-week, double-blind, randomised studies in patients with mildly to moderately active UC were pooled and analysed retrospectively. The mucosal healing analysis focuses on moderately active UC patients (n=391), comprising a majority of patients (84%). Additional analyses examined the relationship between mucosal healing and dose, clinical response to therapy and patient quality of life (Inflammatory Bowel Disease Questionnaire, IBDQ).

RESULTS

At week 3, mucosal healing (endoscopy subscore of 0 or 1) was achieved in 65% of moderately active UC patients on 4.8 g/day and 58% of patients on 2.4 g/day (P=0.219). At week 6, this increased to 80% for 4.8 g/day and 68% for 2.4 g/day (P=0.012). Healing rates with the higher dose were also greater across all extents of disease and in patients with prior steroid use. At 6 weeks, clinical response to therapy and mucosal healing were found to be well correlated (kappa=0.694). Likewise, the change in IBDQ at week 6 showed a significant relationship with mucosal healing (P<0.0001).

CONCLUSION

Mucosal healing rates in UC achieved at 6 weeks were statistically significantly higher with delayed-release mesalazine at 4.8 g/day vs. 2.4 g/day.

Alterations in damage processes in dense cancellous bone following gamma-radiation sterilization

Structurally intact cancellous bone allograft is an attractive tissue form because its high porosity can provide space for delivery of osteogenic factors and also allows for more rapid and complete in-growth of host tissues. Gamma radiation sterilization is commonly used in cancellous bone allograft to prevent disease transmission. Commonly used doses of gamma radiation sterilization (25-35 kGy) have been shown to modify cortical bone post-yield properties and crack propagation but have not been associated with changes in cancellous bone material properties. The purpose of this study was to determine the effects of irradiation on the elastic and yield properties and microscopic tissue damage processes in dense cancellous bone. Cancellous bone specimens (13 control, 14 irradiated to 30 kGy) from bovine proximal tibiae were tested in compression to 1.3% apparent strain and examined for microscopic tissue damage. The yield strain in irradiated specimens (0.93+/-0.11%, mean+/-SD) did not differ from that in control specimens (0.90+/-0.11%, p=0.44). No differences in elastic modulus were observed between groups after accounting for differences in bone volume fraction. However, irradiated specimens showed greater residual strain (p=0.01), increased number of microfractures (p=0.02), and reduced amounts of cross-hatching type damage (p<0.01). Although gamma radiation sterilization at commonly used dosing (30 kGy) does not modify elastic or yield properties of dense cancellous bone, it does cause modifications in damage processes, resulting in increased permanent deformation following isolated overloading.

The effect of mesalazine therapy on quality of life in patients with mildly and moderately active ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) has a major impact on the quality of life (QoL) of affected patients. Patient-reported outcomes have not been thoroughly evaluated in patients with UC receiving oral mesalazine (mesalamine).

AIM

To examine the effect of mesalazine on QoL of patients with mildly and moderately active UC and assess the time course of change, baseline disease severity, mesalazine dose and responder status on QoL parameters.

METHODS

Inflammatory Bowel Disease Questionnaire (IBDQ) data were combined from two double-blind, randomized, multicentre, active-controlled trials assessing 2.4 and 4.8 g/day oral delayed-release mesalazine in 687 patients. Mean score changes from baseline were compared at 3 and 6 weeks and effects of baseline severity, mesalazine dose and response to therapy were examined.

RESULTS

Mesalazine significantly improved IBDQ scores at 3 and 6 weeks (mean increase, 29.6 and 39.7 points, respectively; P < 0.0001 for both). Improvement was greater for patients with moderate disease. Greater week 6 changes occurred in clinical responders than nonresponders (50.1 vs. 23.6 points, respectively; P < 0.0001).

CONCLUSIONS

Delayed-release oral mesalazine produces significant clinical and statistical improvements in QoL of patients with UC by 3 weeks, with further improvement at 6 weeks.

'Perimeteritis' and rural health in Manitoba, Canada: perspectives from rural healthcare managers

INTRODUCTION

Rural areas in many parts of the world are facing issues such as economic restructuring, environmental degradation, aging, and depopulation. These issues impact the health and wellbeing of the people living in rural communities. The purpose of this study was to assess rural healthcare managers' understanding of rural community wellbeing. Specifically, definitions were sought for rural, community, health, wellbeing, and healthy rural community.

METHODS

The research reported in this article is based on a set of interviews with each of the 20 healthcare professionals who either managed healthcare centres or administered specialized programs in the rural health care centres in the Assiniboine Regional Health Authority in southwestern Manitoba, Canada.

RESULTS

Capitalizing on the open-ended structure of the interviews, respondents were thoughtful and philosophical in their responses. This produced a rich array of definitions of rural, community, health, wellbeing, and healthy rural community. In doing so, the struggles for rural communities in southwestern Manitoba were highlighted. The findings also illustrated that definitions of health and wellbeing do not fit standard biomedical or health determinant models alone.

CONCLUSIONS

This study was a follow up to another study that employed focus groups to obtain rural resident perceptions of rural, community, wellbeing, and health in southwestern Manitoba. The study reported on here argued that the specific views of healthcare managers were necessary to further illustrate the complexities in understanding definitions of community and condition. The results are consistent with previous research on this topic in southern Manitoba and the recent literature in that there are no universally accepted definitions of rural, community, wellbeing, or health. Further, the study illustrated that professionals charged with managing healthcare services in rural Manitoba maintain very broad definitions of health and wellbeing. Most significantly, the determinants of health and wellbeing were central to defining individual and community condition and quality of life.

Prospects for the future: is there a role for virally vectored immunocontraception in vertebrate pest management?

Virally vectored immunocontraception (VVIC) has been studied and promoted as an alternative to lethal methods for vertebrate pest control in Australia and New Zealand. Virally vectored immunocontraception offers a potentially humane and species-specific control method with potential for a good benefit–cost outcome, but its applicability for broad-scale management remains unknown. We present case studies for the house mouse, European rabbit, red fox and common brushtail possum and describe the current status of research into the use of VVIC as a broad-scale pest-management tool. All case studies indicated that there are significant problems with delivery and efficacy. The current state of development suggests that VVIC is not presently a viable alternative for the management of these vertebrate pests, and it is highly unlikely that this will change in the foreseeable future. An absence of benefit–cost data also hinders decision-making, and until benefit–cost data become available it will not be clear if there are short- or long-term benefits resulting from the use of VVIC for broad-scale pest management.

Prognostic role of c-met tyrosine kinase receptor expression in breast carcinoma

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Background: Hepatocyte growth factor is a pleotropic growth factor that regulates cell proliferation, survival, tumor angiogenesis and metastasis. Its biological effects are mediated through interaction with its receptor: c-met protein.In this study, we evaluated c-met expression in the homogenous group of 99 patients diagnosed with stage II ductal breast carcinomas (G2, G3). We analyzed 5 and 10-years overall (OS) and disease free survival (DFS). Methods: Microscopic studies were performed on formalin-fixed, paraffin-embedded tumor tissue, obtained during surgery and stained routinely with haematoxylin and eosin. Expression of c-met was evaluated using a standard immunoperoxidase technique and percentage of cells with protein expression was counted. Survival was estimated using Kaplan-Meier method. Results: The expression of c-met was found in 37 (37.37%) tumors, with the strong expression of c-met observed only in 7 (7.07%) specimens. The 5-year DFS in patients with overexpression of c-met was statistically significantly worse (p =0.00493) compared with the group with low or no expression (recurrent rates: 57.14% vs 20.65%). Also with a time horizon of 10 years, high values of c-met expression were associated with the higher rate of recurrences (71.43% vs 30.77%, p = 0.01351). The 5-years OS rate in patients with c-met overexpression was 71.43% compared with 84.78% in the group with low or no expression, but this result did not reach statistical significance (p = 0.30345). Comparable tendency was seen in 10-years OS, which was 42.86% in patients with overexpression and 73.63% with low or no expression (p = 0.06154). Conclusions: The results of the study suggest that c-met overexpression is associated with shorter disease-free survival and it may be a useful prognostic indicator of more aggressive disease in patients with breast carcinoma.

No significant financial relationships to disclose.

Correlation between vascular endothelial growth factor and c-met expressions in breast carcinoma

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Background: Vascular endothelial growth factor (VEGF) is a specific mitogen and survival factor for endothelial cells and a key promoter of angiogenesis. This cytokine selectively induces cells proliferation and migration, increases permeability of microvessels and activates proteolitic enzymes involved in tumor invasiveness. C-met is tyrosine kinase receptor; its activation can increase tumorigenicity, induce cell motility and enhance invasiveness and metastasis. This protein can increase production of protease and urokinase which are associated with membrane degradation crucial for metastasis. The relationships between both cytokines are not clearly identified. In this study, we evaluated VEGF and c-met expression in homogenous group of 99 patients with stage II ductal breast carcinomas and analyzed correlations between both markers. Methods: Microscopic studies were performed on formalin-fixed, paraffin-embedded cancer tissues, obtained during surgery and stained routinely with haematoxylin and eosin. Expression of VEGF and c-met was evaluated using a standard immunoperoxidase technique and area with molecule expression, intensity of color reaction and product of both findings were counted. Association between markers expressions was tested by Spearman Correlation Coefficient. Results: Expression of c-met was found in 37 (37.37%) breast tumors, while expression of VEGF was observed in 67 (67.67%) cases. There were strong correlations between expressions of both cytokines. The relationships were found between area with molecules’ expression (p = 0.0438) and intensity of reaction (p = 0.0461), also in the product of both findings (p = 0.0229). Conclusions: The results of our study confirms hypothesis that c-met may act as an indirect angiogenic factor by inducing expression of VEGF.

No significant financial relationships to disclose.

Prevention of percutaneous endoscopic gastrostomy site infections caused by methicillin-resistant Staphylococcus aureus

Percutaneous endoscopic gastrostomy (PEG) is widely used to maintain enteral nutrition in patients who are unable to swallow. Peristomal wound infection is the most common complication of this procedure. In a hospital endemic for methicillin-resistant Staphylococcus aureus (MRSA), MRSA can be the most common organism associated with these infections. We have evaluated a strategy consisting of screening, skin decontamination and glycopeptide prophylaxis for preventing PEG-site infections. None of the 34 patients who received the decontamination protocol and glycopeptide prophylaxis (Group A) developed PEG-site infections within one month of surveillance. Two patients were infected with MRSA after that period. One of seven patients who received the decontamination protocol alone (Group B) was infected within the period of surveillance, while another patient was infected after that period. Both were infected with MRSA. None of nine patients who received glycopeptide prophylaxis alone (Group C) were infected. The results suggest that the strategy of screening, decontamination and glycopeptide prophylaxis is effective in the prevention of PEG-site infections with MRSA. Further trials are necessary to confirm these findings.

Impairment of MLH1 and CDKN2A in oncogenesis of laryngeal cancer

Our study aimed at elucidating which genetic alterations tend to form a network and could be applied as molecular markers of larynx squamous cell carcinoma (LSCC). A panel of genes involved in tumorigenesis was investigated. To search for the possible mechanisms of gene silencing, loss of heterozygosity (LOH) was analysed followed by testing DNA methylation and protein expression for those genes found with the highest frequency of LOH (CDKN2A (55.4%), MLH1 (46.0%), RB1 (35.7%)). A correlation of both LOH and hypermethylation with the loss of expression for CDKN2A and MLH1 was found. Disrupted Rb pathway (loss of expression of RB1 and/or of CDKN2A) in 55.9% of analysed cases confirmed the hypothesis that RB1 pathway is altered in head and neck squamous cell carcinomas, with CDKN2A (45%), rather than RB1 (11.8%) being more frequently inactivated. In LSCC, LOH tends to occur together in gene pairs or triplets. The pair MLH1/CDKN2A and triplets MLH1/TSG on 8p22/CDKN2A and MLH1/CDKN2A/RB1 are related to staging and grading. LOH in MLH1 correlates with lower and LOH in CDKN2A with higher grades of LSCC. It can be concluded that MLH1 and CDKN2A play an important role in LSCC development and progression.

Impact of bovine tuberculosis on a population of brushtail possums (Trichosurus vulpecula Kerr) in the Orongorongo Valley, New Zealand

Brushtail possums are the main wildlife vectors of bovine tuberculosis (Tb) in New Zealand. Possum–Tb models form the basis of possum control aimed at eradicating the disease, and yet competing models show different behaviour, and are highly sensitive to parameters about which there is considerable uncertainty. One area of great uncertainty is the impact of the disease on possum populations. We investigated the impact of Tb on a local population of brushtail possums in the Orongorongo Valley, Wellington. Bovine Tb was first detected in 1997 at one site within an intensively studied population, but has not been detected in another intensively studied population 3 km away since the early 1980s. Using a Before-After-Control-Impact (BACI) analysis, detection of Tb coincided with a 42% (95% CI = 23–56%) reduction in the odds of apparent yearly survival of a possum >17 months of age, i.e. a decrease in yearly survival from 0.85 to 0.77 in 'good' years, and a decrease from 0.71 to 0.60 in 'bad' years. This suggests that Tb had a significant impact on overall survival. However, there was no impact on local population density in September each year due to compensatory recruitment.

Mortality rate and movements of brushtail possums with clinical tuberculosis (Mycobacterium bovisinfection)

AIM

To describe the mortality rate and movements of brushtail possums (Trichosurus vulpecula) with clinical tuberculosis (Mycobacterium bovis) from a site in native podocarp/hardwood forest, in the Orongorongo Valley, Wellington.

METHODS

Possums with clinical tuberculosis (Tb) were identified through routine trapping on live capture grids and were fitted with radio-collars, and located at approximately monthly intervals for 2.5 years. The survival times of radio-collared tuberculous and non-diseased possums were used to estimate the instantaneous additional mortality rate due to clinical Tb. The spatial behaviour of clinically tuberculous possums was compared with that of non-diseased possums, using both den and trap locations. The frequency of long-distance movements of both tuberculous and non-diseased possums was also determined. A possum was defined as having undertaken along-distance movement when it moved at least 200 m from the centre of its activity range and then returned to its established activity range or died.

RESULTS

The mean survival time of clinically tuberculous possums was 4.7 (SE 0.79) months. The instantaneous additional mortality rate due to clinical Tb was estimated to be between 1.08 year-1 and 2.38 year-1, with the lower figure including an unknown portion of the incubation period in the estimate. Estimates of denning and activity ranges of tuberculous possums were approximately 22-30% larger, on average, than the ranges of non-diseased possums, but the differences were not significant. Both tuberculous and non-diseased possums undertook long-distance movements up to 700 m from the centre of their activity range. However, the majority of tuberculous possums died within or near their established activity range.

CONCLUSIONS

This study estimated the mortality rate during the clinical stages of Tb and, as such, did not represent a true estimate of the disease-induced mortality rate (alpha) used in most epidemiological models of possums and Tb. However, the lower estimate of the additional mortality rate due to clinical disease could be considered an approximation to alpha. The movement patterns of clinically tuberculous possums were, overall, not substantially different from non-diseased possums. The occurrence of long-distance movements by tuberculous possums sometimes coincided with the advanced stage of clinical disease. However, the majority of tuberculous possums died within their established activity area. Long-distance movements by resident possums during the terminal stages of disease represent a direct risk for transmission of Tb to livestock on farms within approximately 1 km of infected possum populations.

Time course of pulmonary response of rats to inhalation of crystalline silica: histological results and biochemical indices of damage, lipidosis, and fibrosis

Previous studies have determined that alpha-quartz (crystalline silica) can cause pulmonary inflammation, damage, and fibrosis. However, the temporal relationship between silica inhalation and pulmonary inflammation, damage, and fibrosis has not been fully examined. To address this gap in our knowledge of silica-induced pulmonary fibrosis, a chronic inhalation study using rats was designed. Specifically, rats were exposed to a silica aerosol (15 mg/m3 silica, 6 h/d, 5 d/wk, 116 d), and measurements of pulmonary inflammation, damage, and fibrosis were monitored throughout the study. We report (1) data demonstrating that the silica aerosol generation and exposure system produced a consistent silica aerosol of respirable size particles; (2) the time course of silica deposition in the lung; (3) calculations that demonstrate that the rats were not in pulmonary overload; (4) histopathological data demonstrating time-dependent enhancement of silica-induced alveolitis, epithelial hypertrophy and hyperplasia, alveolar lipoproteinosis, and pulmonary fibrosis in the absence of overload; and (5) biochemical data documenting the development of lipidosis, lung damage, and fibrosis.

Eplerenone suppresses constrictive remodeling and collagen accumulation after angioplasty in porcine coronary arteries

BACKGROUND

Coronary artery angioplasty triggers healing that causes constrictive remodeling. Because collagen accumulation correlates with constrictive remodeling and aldosterone has been implicated in collagen accumulation, we examined how aldosterone and the mineralocorticoid receptor antagonists spironolactone and eplerenone affect remodeling and collagen in porcine coronary and iliac arteries after angioplasty.

METHODS AND RESULTS

Twenty-four pigs were allocated into 4 treatment groups: oral eplerenone (100 mg/d), oral spironolactone (200 mg/d), subcutaneous aldosterone (400 microgram/d), or no treatment. Twenty-eight days after angioplasty of the coronary arteries, eplerenone increased total vessel area by 30% (P<0.05) and luminal area by nearly 60% (P<0.05) compared with the no-treatment group, without affecting neointima size. These effects were accompanied by a 65% reduction in neointimal and medial collagen density (both P<0.05). Spironolactone was less effective, and aldosterone tended to exert opposite effects on coronary artery structure after angioplasty. These effects were not observed in angioplastied iliac arteries.

CONCLUSIONS

Eplerenone attenuates constrictive remodeling after coronary artery angioplasty by mechanisms involving reduction in collagen accumulation, which thus appears to be an important contributor to constrictive remodeling of angioplastied coronary arteries.

Do "conditions contributing to the death" clarify the predictors of infant mortality in Texas?

Predictors of infant mortality are usually based on the underlying causes reported on infant death certificates. Death certificates also contain space for "Other significant conditions contributing to the death but not resulting in the underlying cause." We investigated whether these "contributing conditions" might clarify the predictors of infant death in Texas or interventions that might reduce deaths from the underlying causes. A "multiple cause of death" file converted the underlying causes and contributing conditions associated with each infant death in 1996 into International Classification of Diseases codes. We ranked the major underlying causes, the conditions contributing to those causes, the conditions contributing to all infant deaths, and the effect of combining the underlying causes with contributing conditions to determine the main predictors of infant mortality. We found that extreme immaturity was the most common condition, causing or contributing to 604 of the 2081 deaths in 1996. We conclude that the underlying causes provide a misleading perception of the major predictors of infant death in Texas; combining them with the conditions contributing to those deaths provides a clearer picture. Given the powerful predictive value of preterm birth for infant mortality, the limited current ability to prevent preterm birth, and the cost of its complications, expanded efforts to improve understanding of its causal processes and develop preventive strategies should be top national and state priorities.

Effect of silica inhalation on the pulmonary clearance of a bacterial pathogen in Fischer 344 rats

Silica inhalation predisposes workers to bacterial infection and impairments in pulmonary defense function. In this study, we evaluated the effect of pre-exposure to silica on lung defense mechanisms by use of a rat pulmonary Listeria monocytogenes infection model. Male Fischer 344 rats were exposed by inhalation to filtered air or silica (15 mg/m3 x 6 h/day x 5 days/wk). After 21 or 59 days of silica exposure, the rats were inoculated intratracheally with 5 x 10(3) L. monocytogenes. At 0 (noninfected controls), 3, and 7 days after infection, the left lungs were removed, homogenized, and the number of viable L. monocytogenes was counted after an overnight culture at 37 degrees C. Bronchoalveolar lavage (BAL) was performed on the right lungs. Alveolar macrophages (AM) were collected, and the AM production of chemiluminescence (CL), an index of reactive oxygen species generation, was measured. The number of lavagable neutrophils (PMNs) and acellular BAL lactate dehydrogenase (LDH) activity were determined as indices of inflammation and injury, respectively. Pre-exposure to silica for 59 days caused substantial increases in PMN number and LDH activity compared with the air controls, whereas silica inhalation for both 21 and 59 days significantly enhanced the pulmonary clearance of L. monocytogenes compared with air controls. Dramatic elevations were also observed in zymosan- and phorbol myristate acetate (PMA)-stimulated CL production by lung phagocytes recovered from rats pre-exposed to silica for 59 days. These results demonstrate that short-term exposure to inhaled silica particles activates lung phagocytes, as evidenced by increases in reactive oxygen species. This up-regulation in the production of antimicrobial oxidants is likely responsible for the enhancement in pulmonary clearance of L. monocytogenes observed with short-term silica inhalation.

Response to balloon injury is vascular bed specific: a consequence of de novo vessel structure?

Relative contributions of remodelling and neointimal hyperplasia to restenosis after coronary angioplasty have been inferred from studies using iliofemoral arteries, despite differences in structure/function and smooth muscle cell lineage. We compared the response to balloon overstretch injury of coronary arteries (C, n = 16) and similar sized branches of the iliac arteries (I, n = 18) using preinjury vessel diameter (P). inflated balloon size in vivo (B) and the manufacturer predicted inflated size (M) to examine arterial compliance, as well as resulting injury and morphology in perfusion fixed vessels. Despite similar degrees of oversizing (M/P) in the coronary and iliac arteries (C, 1.44 +/- 0.04; I, 1.51 +/- 0.02), the compliance to overstretch (B-P/M-P) was significantly greater in the coronary than the iliac arteries (C, 0.71 +/- 0.05; I, 0.51 +/- 0.03) (P <0.05) and was associated with a higher injury score (C, 1.64 +/- 0.31; I, 0.39 +/- 0.18 P < 0.05)--only 5/18 iliac vessels had rupture of the IEL compared with 13/16 in the coronary bed. In a subgroup of animals whose vessels (C:n = 7; I:n = 8) were perfusion fixed 28 days after injury, coronary arteries had greater intimal area (C:1.03 +/- 0.42; I:0.10 +/- 0.03 mm2, P < 0.05) but larger luminal area (C:1.61 +/- 0.71; 1:0.76 +/- 0.51, P < 0.05) due to greater area within EEL (C:3.38 +/- 0.49;1:] .49 +/- 0.54, P < 0.05) or less inward remodelling. The injuries resulting from similar strategies of balloon overstretch in the coronary and the iliac arteries are different and affect healing responses--iliac arteries remodel more while coronary arteries develop more intimal hyperplasia. These results indicate that caution is warranted when extrapolating results from the iliac to the coronary artery when investigating restenosis after angioplasty.

Greater stroke rate during hospitalization for acute heart disease among Mexican Americans than non-Hispanic whites

BACKGROUND AND PURPOSE

This study compared the risk for stroke during acute myocardial infarction (AMI), percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) between Mexican Americans (MAs) and non-Hispanic whites.

METHODS

We examined the age-specific rate ratios (RR) of acute stroke during hospitalization for AMI, CABG and PTCA in a population-based study in Corpus Christi, Tex. by searching the cardiac surveillance data for ICD-9 codes for stroke (430-437). ICD-9 stroke codes were validated by comparing medical chart abstraction with ICD-9 discharge diagnoses.

RESULTS

Stroke codes were found in 220 of the 5,697 admissions for AMI, CABG and PTCA. In the 45- to 59-year age-group MAs had a RR of 2.66 (95% CI 1.36-5.23) relative to non-Hispanic whites. In the 60- to 74-year age-group the RR was 1.52 (95% CI 1.11-2.08). There were no significant differences in the 25- to 44-year age-group. These ethnic relationships were found in nondiabetics but not in diabetics. Women in the 45- to 59-year age-group had a RR of 1.88 (95% CI 1.09-3.25) compared with men, but there were no significant sex differences in the 25- to 44- or 59- to 74-year age-groups. Stroke ICD-9 codes have a poor positive predictive value for acute stroke ranging from 10 to 76%. The stroke misclassifications were nondifferential with respect to ethnicity or sex.

CONCLUSIONS

MAs have a higher stroke rate complicating acute heart disease in Corpus Christi. A rigorous stroke surveillance project is needed to study the burden of stroke in MAs, the United States' largest Hispanic population.

Comparison of reported symptoms of acute myocardial infarction in Mexican Americans versus non-Hispanic whites (the Corpus Christi Heart Project)

This study examines whether there are differences between Mexican Americans and non-Hispanic whites in reported symptoms of acute myocardial infarction (AMI). The symptoms experienced by patients identified in a community-based surveillance program were examined to determine whether between-group differences existed by ethnicity, gender, and diabetic status. Data were available regarding the symptoms of 589 patients, between the ages of 25 and 74 years, who were hospitalized and diagnosed as either having definite or possible AMI in special care units at 1 of 7 hospitals in Corpus Christi, Texas. The most frequently reported symptoms were chest pain (83.2%), chest pressure or discomfort (67.6%), sweating (64.2%), fatigue (62.6%), dyspnea (60.3%), and arm or jaw pain (58.2%). After adjusting for age, diabetes mellitus, and gender, and relative to non-Hispanic whites, Mexican Americans were more likely to report chest pain, upper back pain, and palpitations, and less likely to report arm or jaw pain. Likewise, relative to men, women were more likely to report fatigue, dyspnea, dizziness, upper back pain, palpitations, and cough, and were less likely to report chest pain. Significant differences were also observed when older patients' symptoms were compared with younger patients' symptoms.

Association between the severity of chronic lung disease and first-year outcomes of very low birth weight infants

OBJECTIVE

The objective of this study was to determine if there is an association between the severity of chronic lung disease in very low birth weight infants (as assessed by the duration of supplemental oxygen requirements in the neonatal period) and first-year neurodevelopmental, sensory, and growth outcomes as well as duration of neonatal hospitalization and first-year hospital readmissions.

STUDY DESIGN

Retrospective chart review with matched subject groups.

METHODS

The subjects of this study were very low birth weight infants born between 1987 and 1991 in a 17-county perinatal region of North Carolina. Infants were categorized into one of three groups on the basis of duration of supplemental oxygen requirements. Infants who were breathing room air by 28 days were classified as having no chronic lung disease; infants who required supplemental oxygen at 28 days but not at 36 weeks postmenstrual age were classified as having mild chronic lung disease; and infants who required supplemental oxygen at 36 weeks postmenstrual age were classified as having severe chronic lung disease. Infants were matched for birth weight, sex, and race. The matched groups (n = 174) were compared with respect to the incidence of first year adverse neurodevelopmental and sensory outcomes, growth patterns, and hospital readmissions during the first year. Results were analyzed with general linear models and logistic regression analyses.

RESULTS

The incidence of any adverse neurodevelopmental or sensory outcome increased as severity of chronic lung disease increased from none (3.6%) to mild (21.4%) to severe (31.6%, p < 0.001). Growth patterns were similar in infants with no and mild chronic lung disease, but infants with severe chronic lung disease were significantly lighter (p < 0.01) and shorter (p < 0.005) at 40 weeks postmenstrual age and significantly lighter at 1 year adjusted age (p < 0.05). The duration of the initial hospitalization increased with chronic lung disease severity (p < 0.001). Infants with severe chronic lung disease were readmitted to the hospital significantly more often (p < 0.005) than infants with no chronic lung disease or mild chronic lung disease.

CONCLUSIONS

Very low birth weight infants who required supplemental oxygen at or beyond 28 days were at increased risk for adverse neurodevelopmental and sensory outcomes, but only those infants who continued to require supplemental oxygen at 36 weeks were at increased risk for poor growth and readmission to the hospital.

Local anesthesia for infrainguinal arterial reconstruction

PURPOSE

Perioperative cardiac complications occur in 4% to 6% of patients undergoing infrainguinal revascularization under general, spinal, or epidural anesthesia. The risk may be even greater in patients whose cardiac disease cannot be fully evaluated or treated before urgent limb salvage operations. Prompted by these considerations, we investigated the feasibility and results of using local anesthesia in these high-risk patients.

METHODS

From January 1, 1994, through August 30, 1996, 86 infrainguinal reconstructions were performed under local infiltration anesthesia (0.5% or 1.0% lidocaine). Supplementary intravenous sedation with propofol or other agents was given as needed for patients comfort. Most patients had arterial lines but Swan Ganz catheters were used infrequently. Postoperatively, continuous electrocardiographic monitoring was continued in the intermediate or intensive care units. Patients ranged in age from 37 to 86 years (mean 68 +/- 12); 47% were diabetic, 69% had severe coronary artery disease, and 14% had end-stage renal disease.

RESULTS

Operations included 7 femoral-femoral, 21 femoral-popliteal, 16 femoral-tibial and 13 popliteal-tibial bypass grafts, 9 pseudoaneurysms, and 20 distal graft revisions (+/- thrombectomy). Autogenous vein was used in eight of the femoral-popliteal and all of the femoral-tibial and popliteal-tibial bypass grafts. There were two postoperative deaths. One patient died of a stroke (1.2%) on postoperative day (POD) 2 and one died on POD 27 of unknown cause. Two other (2%) patients had nonfatal subendocardial myocardial infarctions. Conversion to general anesthesia was required in four (5%) operations, three because patients became agitated and one because a long segment of vein had to be harvested from the opposite leg. Otherwise, patients tolerated the procedures well and postanesthetic recovery problems were minimized.

CONCLUSIONS

Limb salvage operations can be done under local anesthesia with acceptable complication rates. In selected patients with high-risk coronary artery disease, local anesthesia has theoretic and practical advantages and should be considered an alternative to general or regional anesthesia.

Malignant rhabdoid tumor of brain: an aggressive clinical entity

OBJECTIVE

We report three patients with malignant rhabdoid tumor (MRT) of the brain, two children and an adult. There were three purposes to this report: to describe the clinical course in an adult with MRT; to describe the interesting histopathological metamorphosis of one of the tumors; and to report the outcome of the treatment regimens we used in order to help guide future treatment. Since these tumors are quite rare it is important to continue to try new regimens in the search for effective therapy rather than to repeat ineffective ones.

METHOD

Report of three patients.

RESULTS

The clinical course in all three patients was typical of these aggressive neoplasms in that chemotherapy and radiotherapy were ineffective in modifying the rapid deterioration leading to death.

CONCLUSIONS

MRT can occur in adults. Autopsy in one patient showed that the tumor seemed to undergo an evolution in appearance when compared with the original pathology specimen from craniotomy. Administration of systemic therapy should be prompt and include intrathecal chemotherapy.

An assessment of the validity of ICD Code 410 to identify hospital admissions for myocardial infarction: The Corpus Christi Heart Project

BACKGROUND

The identification of myocardial infarction (MI) is typically based on finding events designated by a nosologist with the appropriate International Classification of Diseases (ICD) code, currently code 410. These codes are applied based on review of medical records or death certificates. However, other factors, including reimbursement considerations, may influence the coding process, especially for hospitalizations. Thus, the validity of using ICD code 410 to identify MI must be assessed.

METHODS

The Corpus Christi Heart Project (CCHP) is a population-based surveillance programme for hospitalized MI. Patients were identified using concurrent ascertainment in coronary care units and retrospective review of medical records. Events were validated as definite or possible MI using data regarding chest pain, electrocardiographic changes and cardiac enzymes. The validity of using ICD code 410 to identify cases of MI was assessed by calculating the sensitivity, specificity, predictive values and efficiency of ICD code 410 versus the CCHP 'gold standard'.

RESULTS

Use of ICD code 410 identified 80.9% (401/496) of definite MI, but only 19.0% (243/1280) of possible MI. Only 12.3% (90/734) of discharges with an ICD 410 code received a 'no MI' designation based on the 'gold standard'. The efficiency of ICD code 410 for identifying MI was 92.0% for definite MI and 77.1% for definite and possible MI.

CONCLUSIONS

The use of ICD code 410 to identify hospitalized cases of MI results in a modestly biased overestimate of the number of definite MI hospitalizations; however, this approach warrants consideration due to the expense of validation procedures.