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1.
Anaesthesia ; 78(2): 170-179, 2023 02.
Article in English | MEDLINE | ID: mdl-36314355

ABSTRACT

The opioid crisis remains a major public health concern. In ambulatory surgery, persistent postoperative opioid use is poorly described and temporal trends are unknown. A population-based retrospective cohort study was undertaken in Ontario, Canada using routinely collected administrative data for adults undergoing ambulatory surgery between 1 January 2013 and 31 December 2017. The primary outcome was persistent postoperative opioid use, defined using best-practice methods. Multivariable generalised linear models were used to estimate the association of persistent postoperative opioid use with prognostic factors. Temporal trends in opioid use were examined using monthly time series, adjusting for patient-, surgical- and hospital-level variables. Of 340,013 patients, 44,224 (13.0%, 95%CI 12.9-13.1%) developed persistent postoperative opioid use after surgery. Following multivariable adjustment, the strongest predictors of persistent postoperative opioid use were pre-operative: utilisation of opioids (OR 9.51, 95%CI 8.69-10.39); opioid tolerance (OR 88.22, 95%CI 77.21-100.79); and utilisation of benzodiazepines (OR 13.75, 95%CI 12.89-14.86). The time series model demonstrated a small but significant trend towards decreasing persistent postoperative opioid use over time (adjusted percentage change per year -0.51%, 95%CI -0.83 to -0.19%, p = 0.003). More than 10% of patients who underwent ambulatory surgery experienced persistent postoperative opioid use; however, there was a temporal trend towards a reduction in persistent opioid use after surgery. Future studies are needed that focus on interventions which reduce persistent postoperative opioid use.


Subject(s)
Analgesics, Opioid , Opioid-Related Disorders , Adult , Humans , Analgesics, Opioid/therapeutic use , Ambulatory Surgical Procedures , Pain, Postoperative/drug therapy , Pain, Postoperative/epidemiology , Retrospective Studies , Incidence , Risk Factors , Drug Tolerance , Opioid-Related Disorders/epidemiology , Opioid-Related Disorders/etiology , Ontario/epidemiology
2.
Annu Rev Cell Dev Biol ; 34: 189-215, 2018 10 06.
Article in English | MEDLINE | ID: mdl-30296390

ABSTRACT

We review what is currently understood about how the structure of the primary solid component of mucus, the glycoprotein mucin, gives rise to the mechanical and biochemical properties of mucus that are required for it to perform its diverse physiological roles. Macroscale processes such as lubrication require mucus of a certain stiffness and spinnability, which are set by structural features of the mucin network, including the identity and density of cross-links and the degree of glycosylation. At the microscale, these same features affect the mechanical environment experienced by small particles and play a crucial role in establishing an interaction-based filter. Finally, mucin glycans are critical for regulating microbial interactions, serving as receptor binding sites for adhesion, as nutrient sources, and as environmental signals. We conclude by discussing how these structural principles can be used in the design of synthetic mucin-mimetic materials and provide suggestions for directions of future work in this field.


Subject(s)
Glycoproteins/chemistry , Mucin-1/chemistry , Mucus/chemistry , Structure-Activity Relationship , Animals , Glycoproteins/genetics , Glycosylation , Humans , Mucin-1/genetics , Mucus/metabolism , Permeability , Rheology
3.
Sci Rep ; 8(1): 814, 2018 01 16.
Article in English | MEDLINE | ID: mdl-29339831

ABSTRACT

Antimicrobial resistance (AMR) is a global health issue. In an effort to minimize this threat to astronauts, who may be immunocompromised and thus at a greater risk of infection from antimicrobial resistant pathogens, a comprehensive study of the ISS "resistome' was conducted. Using whole genome sequencing (WGS) and disc diffusion antibiotic resistance assays, 9 biosafety level 2 organisms isolated from the ISS were assessed for their antibiotic resistance. Molecular analysis of AMR genes from 24 surface samples collected from the ISS during 3 different sampling events over a span of a year were analyzed with Ion AmpliSeq™ and metagenomics. Disc diffusion assays showed that Enterobacter bugandensis strains were resistant to all 9 antibiotics tested and Staphylococcus haemolyticus being resistant to none. Ion AmpliSeq™ revealed that 123 AMR genes were found, with those responsible for beta-lactam and trimethoprim resistance being the most abundant and widespread. Using a variety of methods, the genes involved in antimicrobial resistance have been examined for the first time from the ISS. This information could lead to mitigation strategies to maintain astronaut health during long duration space missions when return to Earth for treatment is not possible.


Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Enterobacter/isolation & purification , Environmental Microbiology , Spacecraft , Staphylococcus haemolyticus/isolation & purification , Disk Diffusion Antimicrobial Tests , Enterobacter/drug effects , Enterobacter/genetics , Genes, Bacterial , Staphylococcus haemolyticus/drug effects , Staphylococcus haemolyticus/genetics , Whole Genome Sequencing
4.
Urol Pract ; 5(2): 113-119, 2018 Mar.
Article in English | MEDLINE | ID: mdl-37300202

ABSTRACT

INTRODUCTION: The influence of multispecialty guidelines on practice patterns in the emergency department is unknown. We documented practice patterns in our emergency department among patients presenting with acute renal colic. METHODS: We identified practice patterns in the treatment of nephrolithiasis in our emergency department via a retrospective chart review of 469 patients from 2013 to 2015. We compared practice patterns to available guidelines over the domains of 1) diagnostic and imaging studies, 2) medications and 3) referral to urology. RESULTS: There was a slight preference toward noncontrast computerized tomography (29%) as a single modality imaging study compared to renal ultrasound (26%). Overall 74% of renal ultrasounds were completed at bedside by emergency department physicians. Alpha blockers were used for medical expulsive therapy in 47% of patients. However, 133 patients with ureteral stones did not receive medical expulsive therapy. Only 34% of the total cohort received a urology consultation in the emergency department or subsequent outpatient referral. CONCLUSIONS: We noted variability in practice patterns for patients presenting with nephrolithiasis in the emergency department compared to guidelines provided by several professional organizations. There is inconsistent use of imaging studies, underuse of medical expulsive therapy and underuse of urology, highlighting a need for collaborative standardization of a diagnostic and treatment protocol to enhance quality of care.

6.
Vet Rec ; 180(6): 148, 2017 Feb 11.
Article in English | MEDLINE | ID: mdl-28077756

ABSTRACT

This paper examines farmer attitudes towards the development of a voluntary risk-based trading scheme for cattle in England as a risk mitigation measure for bovine tuberculosis (bTB). The research reported here was commissioned to gather evidence on the type of scheme that would have a good chance of success in improving the information farmers receive about the bTB risk of cattle they buy. Telephone interviews were conducted with a stratified random sample of 203 cattle farmers in England, splitting the interviews equally between respondents in the high-risk area and low-risk area for bTB. Supplementary interviews and focus groups with farmers were also carried out across the risk areas. Results suggest a greater enthusiasm for a risk-based trading scheme in low-risk areas compared with high-risk areas and among members of breed societies and cattle health schemes. Third-party certification of herds by private vets or the Animal and Plant Health Agency were regarded as the most credible source, with farmer self-certification being favoured by sellers, but being regarded as least credible by buyers. Understanding farmers' attitudes towards voluntary risk-based trading is important to gauge likely uptake, understand preferences for information provision and to assist in monitoring, evaluating and refining the scheme once established.


Subject(s)
Commerce/methods , Farmers/psychology , Health Knowledge, Attitudes, Practice , Tuberculosis, Bovine/prevention & control , Voluntary Programs/organization & administration , Animals , Cattle , England , Humans , Program Development , Qualitative Research , Risk Assessment
7.
S. Afr. j. child health (Online) ; 11(3): 117-121, 2017. ilus
Article in English | AIM (Africa) | ID: biblio-1270306

ABSTRACT

Background. Autism spectrum disorder (ASD) is a neurodevelopmental disorder that appears before the age of 3 years. Symptoms reflect delayed or abnormal social interaction and communication skills, with restricted or repetitive behaviour warranting the need for early intensive treatment.Methods. The aim of the study was to investigate the knowledge and views of parents regarding treatments for their children, aged between 5 and 9 years old with ASD, in eThekwini Metropolitan Municipality, South Africa. An embedded mixed methods research design was utilised. Nonrandom purposive sampling was used to select 46 parents of children with ASD. A 42-item questionnaire was used and the data were interpreted using descriptive statistics and thematic analysis.Results. More than half of the parents (53%) were unfamiliar with or had only heard of treatments in question, while 13.4% had a practical understanding of the treatments. Of all the treatments, parents rated their knowledge of speech-language therapy (SLT) most highly. The majority (68%) stated that they had difficulties accessing ASD treatment facilities and healthcare professionals, and perceived treatments as being costly. Even so, 74% of parents reported that they had a good relationship with their healthcare professional.Conclusion. The above findings should be viewed as motivation for health professionals to share information regarding the range of ASD treatments. They can assist parents in accessing appropriate facilities, recommend treatments that are supported by research, and update their knowledge on advances in ASD treatment


Subject(s)
Autistic Disorder , Child of Impaired Parents , Neurodevelopmental Disorders , South Africa , Speech-Language Pathology
9.
Br Poult Sci ; 55(5): 559-68, 2014.
Article in English | MEDLINE | ID: mdl-25350726

ABSTRACT

High standards of biosecurity are known to reduce the risk of disease outbreaks; however, uptake of advice and implementation of biosecurity measures are dependent on many factors. This study assessed the uptake of targeted biosecurity advice by 60 laying hen farms provided during biosecurity audit visits. Advice was provided as bullet point cards focusing on specific areas identified as benefitting from improvement. These covered site entrance, site tidiness, vaccination, boot hygiene, hand hygiene, house tidiness, rodent control, fly control, red mite control and cleaning and disinfection between flocks. Background knowledge of Salmonella and biosecurity and farmers' willingness and intent to implement additional measures were assessed. About 50% of the principal decision-makers had basic background knowledge of Salmonella, with 22% considered well informed; almost all agreed that biosecurity could impact on Salmonella control and many appeared willing to implement additional biosecurity measures. Sixty-three per cent of study farms were categorised using the Defra Farmer Segmentation Model as Modern Family Businesses (MFBs), with 7-11% of farms being categorised as Custodian, Lifestyle Choice, Pragmatist or Challenged Enterprise; however, categorisation, did not determine uptake of advice. The most frequently used advice cards were boot hygiene, red mite control, hand hygiene, site entrance and cleaning and disinfection; uptake of advice ranged from 54 to 80% depending on the advice card. Uptake of advice by the farmers was encouraging, especially considering it was being provided by people other than their usual source of biosecurity information. Those who did not implement the recommended measures cited cost, difficulty of enforcement and practicality as the main reasons. However, the positive uptake of advice and implementation of recommended measures by many farmers demonstrates that targeted advice, discussed face to face with farmers, on a small number of key areas, is a potentially effective method of providing biosecurity information to complement more lengthy formal advisory reports.


Subject(s)
Animal Husbandry/methods , Chickens , Health Knowledge, Attitudes, Practice , Poultry Diseases/prevention & control , Salmonella Infections, Animal/prevention & control , Salmonella/physiology , Security Measures , Animals , England , Female , Humans , Poultry Diseases/microbiology , Salmonella Infections, Animal/microbiology , Socioeconomic Factors , Surveys and Questionnaires , Wales
11.
Physiol Meas ; 35(7): 1425-37, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24875387

ABSTRACT

In this paper an investigation of the gain, delay, and time-constant parameters of the transfer function describing the relation between fraction of inspired oxygen (FiO2) and oxygen saturation in the blood (SpO2) in preterm infants is presented. The parameters were estimated following FiO2 adjustments and goodness of fit was used to assess the validity of the model when using an assumed first-order transfer function. For responses identified to be first-order, the estimated parameters were then clustered to identify areas where they tended to be concentrated. Each group described an operating region of the transfer function; thus, predicting the right operating region could potentially assist a range-based robust inspired oxygen controller to provide more optimal control by adapting itself to different clusters. Accordingly, the samples were assigned labels based on their cluster associations and 14 features available at the time of each adjustment were used as inputs to an artificial neural network to classify the clustered samples. The validity study suggested that 37% of the adjustments were followed by first-order responses. Prediction studies on the first-order responses indicated that the clusters could be predicted with an average accuracy of 64% when the parameters were divided into two groups.


Subject(s)
Continuous Positive Airway Pressure , Diagnostic Techniques, Cardiovascular , Infant, Premature/physiology , Oxygen/blood , Signal Processing, Computer-Assisted , Algorithms , Cluster Analysis , Databases, Factual , Humans , Infant , Inhalation , Neural Networks, Computer
12.
Clin Toxicol (Phila) ; 51(9): 879-85, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24059251

ABSTRACT

CONTEXT: On October 29, 2012, Hurricane Sandy made landfall and devastated New York's metropolitan area, causing widespread damage to homes and the utility infrastructure. Eight days later, snow and freezing temperatures from a nor'easter storm delayed utility restoration. OBJECTIVE: To examine carbon monoxide (CO) exposures in the 2 weeks following Hurricane Sandy. Methods. This was a retrospective review of prospectively collected, standardized, and de-identified data sets. CO exposures and poisonings identified from two electronic surveillance systems, the New York City Poison Control Center (NYCPCC) and New York City's Syndromic Surveillance Unit, were compared with CO exposures from identical dates in 2008-2011. Data collected from the poison center included exposure type, CO source, poisoning type, treatment, and outcomes. Data collected from the Syndromic Surveillance Unit cases, which were identified by CO-related chief complaints presenting to NYC hospitals, included visit date and time, and patient demographics. RESULTS: Four hundred thirty-seven CO exposures were reported to the NYCPCC, 355 from NYC callers, and the remainder from surrounding counties, which represented a significant increase when compared with CO exposures from identical dates in the preceding 4 years (p < 0.001). The total cases that were reported to the NYCPCC in 2008, 2009, 2010, and 2011 were 18, 13, 24, and 61, respectively. Excluding a single apartment fire that occurred (n = 311), the more common sources of CO were grilling indoors (26.2%) and generators (17.5%). Syndromic surveillance captured 70 cases; 6 cases were captured by both data sets. CONCLUSIONS: CO exposures following weather-related disasters are a significant public health concern, and the use of fuel-burning equipment is a clear source of storm-related morbidity and mortality. Multiple real-time epidemiologic surveillance tools are useful in estimating the prevalence of CO exposure and poisoning and are necessary to assist public health efforts to prevent CO poisoning during and after disasters.


Subject(s)
Carbon Monoxide Poisoning/epidemiology , Carbon Monoxide/toxicity , Cyclonic Storms , Disasters , Inhalation Exposure/adverse effects , Air Pollution, Indoor/adverse effects , Air Pollution, Indoor/prevention & control , Carbon Monoxide Poisoning/physiopathology , Carbon Monoxide Poisoning/prevention & control , Carbon Monoxide Poisoning/therapy , Cooking , Databases, Factual , Electric Power Supplies/adverse effects , Emergency Service, Hospital , Epidemiological Monitoring , Female , Humans , Inhalation Exposure/prevention & control , Male , New York City/epidemiology , Poison Control Centers , Prevalence , Retrospective Studies , Snow
13.
Biomed Sci Instrum ; 48: 470-7, 2012.
Article in English | MEDLINE | ID: mdl-22846321

ABSTRACT

NASA’s extra-vehicular activities (EVAs) involve exposure to high energy photons while breathing 100% oxygen. Using previously verified mouse models, our laboratory is studying whether low dose irradiation under these hyperoxic conditions could lead to an increase in carcinogenic potential. To simulate the environment astronauts encounter during an EVA, enclosed chambers were constructed that allowed for mouse movement, controlled gas conditions, and uniform radiation dose delivery. Custom-built gas chambers with input/output gas valves and dividers that allowed for uniform gas flow were used to keep 6 unanesthetized mice separated while they were irradiated. The chambers were supplied with 100% oxygen or air using ball valves linked together with T-splitters. A calibrated ion chamber was used to verify the radiation dose distribution across an entire chamber. Mice were placed in the gas environments for 0.5 h, irradiated with a 10 or 18 MV photon beam from a medical linear accelerator, and left in their gas environment for 2 h post-irradiation. We irradiated 200 mice (5 different doses between 0-1000 mGy) under normoxic or 100% oxygen conditions. For the next step of this research, these mice will be euthanized 9 months post-irradiation, and lung tumors will be counted and sized to determine if hyperoxia increases the carcinogenic effect for this model.

14.
J Perinatol ; 32(2): 111-6, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21637192

ABSTRACT

OBJECTIVE: The objective of this study is to compare the effects of back-up ventilation rates (BURs) on triggered inflations and patient cardiorespiratory stability during assist-control/volume guarantee ventilation (AC/VG). STUDY DESIGN: This study is a randomized crossover trial conducted in a neonatal unit in an Australian tertiary NICU. In all, 26 stable preterm infants on AC/VG ventilation were studied at BUR settings of 30, 40 and 50 min(-1). Inflation rate, triggering and cardiorespiratory measures of patient stability were compared during 20 min epochs with 10 min washout periods. RESULT: The 26 infants studied were median (inter-quartile range) gestational age 27 (26, 30) weeks, birth weight 0.84 (0.75, 1.14) kg and FiO(2) 0.24 (0.21, 0.31) and age 6 (4, 19) days. At BURs of 30, 40 and 50, the proportions of inflations, which were triggered, were mean (s.d.) 85% (11), 75% (19) and 61% (25); P<0.01 for all comparisons. Total delivered inflation rates were 56 (8), 58 (9) and 62 (8) min(-1), respectively. Cardiorespiratory parameters did not vary between the settings. CONCLUSION: Using a lower BUR allows greater triggering of ventilator inflations. Cardiorespiratory parameters including CO(2) levels were stable at all rates.


Subject(s)
Infant, Premature , Respiration, Artificial/instrumentation , Respiratory Insufficiency/therapy , Tidal Volume/physiology , Australia , Birth Weight , Cross-Over Studies , Female , Follow-Up Studies , Gestational Age , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Male , Pulmonary Gas Exchange , Respiration, Artificial/methods , Respiratory Insufficiency/diagnosis , Respiratory Mechanics , Risk Assessment , Time Factors , Treatment Outcome , Ventilator Weaning , Ventilators, Mechanical/statistics & numerical data
15.
Br J Cancer ; 105(12): 1940-8, 2011 Dec 06.
Article in English | MEDLINE | ID: mdl-22146831

ABSTRACT

BACKGROUND: In neuroblastoma (NB), the presence of segmental chromosome alterations (SCAs) is associated with a higher risk of relapse. METHODS: In order to analyse the role of SCAs in infants with localised unresectable/disseminated NB without MYCN amplification, we have performed an array CGH analysis of tumours from infants enrolled in the prospective European INES trials. RESULTS: Tumour samples from 218 out of 300 enroled patients could be analysed. Segmental chromosome alterations were observed in 11%, 20% and 59% of infants enroled in trials INES99.1 (localised unresectable NB), INES99.2 (stage 4s) and INES99.3 (stage 4) (P<0.0001). Progression-free survival was poorer in patients whose tumours harboured SCA, in the whole population and in trials INES99.1 and INES99.2, in the absence of clinical symptoms (log-rank test, P=0.0001, P=0.04 and P=0.0003, respectively). In multivariate analysis, a SCA genomic profile was the strongest predictor of poorer progression-free survival. CONCLUSION: In infants with stage 4s MYCN-non-amplified NB, a SCA genomic profile identifies patients who will require upfront treatment even in the absence of other clinical indication for therapy, whereas in infants with localised unresectable NB, a genomic profile characterised by the absence of SCA identifies patients in whom treatment reduction might be possible. These findings will be implemented in a future international trial.


Subject(s)
Chromosome Aberrations , Neuroblastoma/pathology , Nuclear Proteins/genetics , Oncogene Proteins/genetics , Humans , Infant , N-Myc Proto-Oncogene Protein , Neuroblastoma/genetics , Prognosis , Prospective Studies , Recurrence , Survival Analysis
16.
J Perinatol ; 31(12): 799-801, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22124516

ABSTRACT

Management of atelectasis and lung collapse in ventilated neonates remains a common challenge in the neonatal intensive care unit. Recombinant human DNase (rhDNase) is an established treatment of atelectasis in cystic fibrosis and its use is also reported in the management of asthma, respiratory syncitial virus bronchiolitis and bronchiectasis to liquefy sputum and aid its clearance from the lungs. We report the use of rhDNase in a subgroup of ventilated neonates with severe end-stage respiratory failure and atelectasis. Three of the four patients showed clinical improvement. A previously undiagnosed lung anomaly was subsequently identified in the fourth patient. Future randomized studies could examine any potential benefits of this emerging therapy.


Subject(s)
Deoxyribonuclease I/administration & dosage , Pulmonary Atelectasis/therapy , Respiration, Artificial , Aerosols , Female , Humans , Infant, Newborn , Male , Pulmonary Atelectasis/complications , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy , Sepsis/complications , Trachea
17.
J Perinatol ; 31(9): 575-85, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21760587

ABSTRACT

A recent systematic review and meta-analysis shows that volume-targeted ventilation (VTV) compared with pressure-limited ventilation (PLV) reduce death and bronchopulmonary dysplasia, pneumothorax, hypocarbia and severe cranial ultrasound abnormalities. In this paper, we present published research and our experience with volume guarantee (VG) ventilation, a VTV mode available on the Dräger Babylog 8000plus and VN500 ventilators. The VG algorithm measures the expired tidal volume (V(T)) for each inflation and adjusts the peak inflating pressure for the next inflation to deliver a V(T) set by the clinician. The advantage of controlling expired V(T) is that this is less influenced by endotracheal tube leak than inspired V(T). VG ventilation can be used with an endotracheal tube leak up to ∼50%. Initial set V(T) for infants with respiratory distress syndrome should be 4.0 to 5.0 ml kg(-1). The set V(T) should be adjusted to maintain normocapnoea. Setting the peak inflating pressure limit well above the working pressure is important to enable the ventilator to deliver the set V(T), and to avoid frequent alarms. This paper provides a practical guide on how to use VG ventilation.


Subject(s)
Respiration, Artificial/methods , Respiratory Distress Syndrome, Newborn/therapy , Ventilators, Mechanical , Humans , Infant, Newborn , Practice Guidelines as Topic , Respiration, Artificial/instrumentation
18.
Acta Paediatr ; 100(1): 67-70, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20712839

ABSTRACT

BACKGROUND: Ventilator frequency is one of the determinants of tidal volume delivery during high-frequency ventilation. Clinicians increasingly use data on ventilator displays to inform their decisions. AIM: To measure the frequencies delivered by the Dräger Babylog 8000plus ventilator when used in high-frequency mode. METHODS: Ventilator waveforms using a test lung were recorded at the full range of settings 5-20 Hz using Spectra software at 1000 Hz. The changes in frequency produced by a 1-Hz change in set frequency were calculated. Actual and displayed frequencies were compared. RESULTS: For settings up to 12 Hz, median (range) difference between set and delivered frequencies was 0 (-0.4 to +0.1) Hz. Above 12 Hz, delivered frequency varied by -0.3 (-1.9 to +0.3) Hz. For 1-Hz changes in frequency settings, in the range 5-12 Hz, 1-Hz changes produced a change in delivered frequency of 1.0 (0.6-1.4) Hz. Above 12 Hz, the corresponding changes were 0.7 (0-2.9) Hz. The ventilator displays the set frequency during operation rather than the delivered frequency. CONCLUSION: At 12 Hz and below, the differences between set and delivered frequencies were relatively small compared with those at 13 Hz and higher. Above 13 Hz, the difference between set and delivered frequencies was up to 2.9 Hz. Some frequency setting changes did not result in a change in delivered frequency.


Subject(s)
Equipment and Supplies, Hospital , High-Frequency Ventilation/standards , Intensive Care Units, Neonatal , Ventilators, Mechanical/standards , Calibration/standards , Data Display , Equipment Design , Humans , Infant, Newborn , Tidal Volume
19.
J Microsc ; 238(3): 189-99, 2010 Jun 01.
Article in English | MEDLINE | ID: mdl-20579257

ABSTRACT

Preparation and sectioning of bacterial spores by focused ion beam and subsequent high resolution secondary ion mass spectrometry analytical imaging is demonstrated. Scanning transmission electron microscopy mode imaging in a scanning electron microscope is used to show that the internal structure of the bacterial spore can be preserved during focused ion beam sectioning and can be imaged without contrast staining. Ion images of the sections show that the internal elemental distributions of the sectioned spores are preserved. A rapid focused ion beam top-sectioning method is demonstrated to yield comparable ion images without the need for sample trenching and section lift-out. The lift-out and thinning method enable correlated transmission electron microscopy and high resolution secondary ion mass spectrometry analyses. The top-cutting method is preferable if only secondary ion mass spectrometry analyses are performed because this method is faster and yields more sample material for analysis; depth of useful sample material is approximately 300 nm for top-cut sections versus approximately 100 nm for electron-transparent sections.


Subject(s)
Bacillus/chemistry , Bacillus/ultrastructure , Image Processing, Computer-Assisted/methods , Spectrometry, Mass, Secondary Ion/methods , Spores/chemistry , Spores/ultrastructure , Microscopy, Electron, Transmission/methods
20.
Eur Spine J ; 18(9): 1272-8, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19479285

ABSTRACT

Percutaneous vertebroplasty, comprising an injection of polymethylmethacrylate (PMMA) into vertebral bodies, is a practical procedure for the stabilization of osteoporotic compression fractures as well as other weakening lesions. Cement leakage is considered to be one of the major and most severe complications during percutaneous vertebroplasty. The viscosity of the material plays a key role in this context. In order to enhance the safety for the patient, a rheometer system was developed to measure the cement viscosity intraoperatively. For this development, it is of great importance to know the proper viscosity to start the procedure determined by experienced surgeons and the relation between the time period when different injection devices are used and the cement viscosity. The purpose of the study was to investigate the viscosity ranges for different injection systems during conventional vertebroplasty. Clinically observed viscosity values and related time periods showed high scattering. In order to get a better understanding of the clinical observations, cement viscosity during hardening at different ambient temperatures and by simulation of the body temperature was investigated in vitro. It could be concluded, that the direct viscosity assessment with a rheometer during vertebroplasty can help clinicians to define a lower threshold viscosity and thereby decrease the risk of leakage and make adjustments to their injection technique in real time. Secondly, the acceleration in hardening of PMMA-based cements at body temperature can be useful in minimizing leakages by addressing them with a short injection break.


Subject(s)
Bone Cements/chemistry , Polymethyl Methacrylate/chemistry , Postoperative Complications/prevention & control , Spinal Fractures/surgery , Vertebroplasty/methods , Aged , Aged, 80 and over , Bone Cements/therapeutic use , Female , Humans , Injections/instrumentation , Injections/methods , Male , Polymers/chemistry , Polymers/therapeutic use , Polymethyl Methacrylate/therapeutic use , Postoperative Complications/etiology , Postoperative Complications/physiopathology , Pulmonary Embolism/etiology , Pulmonary Embolism/physiopathology , Pulmonary Embolism/prevention & control , Time Factors , Viscosity
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